九州大学 研究者情報
論文一覧
岡安 崇史(おかやす たかし) データ更新日:2020.06.16

准教授 /  農学研究院 環境農学部門 生産環境科学講座


原著論文
1. Koichi Nomura, Akihiro Takada, Hirosato Kunishige, Yukio Ozaki, Takashi Okayasu, Daisuke Yasutake, Masaharu Kitano, Long-term and continuous measurement of canopy photosynthesis and growth of spinach, Environmental Control in Biology, 10.2525/ecb.58.21, 58, 2, 21-29, 2020.01, [URL], To understand long-term association between canopy-scale photosynthesis and growth, we continuously and simultaneously measured the net photosynthetic rate (Ac) and leaf area index (LAI) of a spinach canopy from transplantation to harvesting. This long-term measurement was enabled by combining an open-type flux chamber method and image analysis of top-of-view canopy photographs. The photosynthetic photon flux density (PPFD) was the major determinant of Ac during a short-term period, but the change in Ac was significantly amplified by an increase in LAI during a long-term period. LAI, measured with reliable accuracy from gap fractions (projected non-leaf areas) of top-of-view photographs, increased exponentially through the growth period. These results indicate a positive feedback loop between photosynthesis and growth (i.e., the growth of leaves amplifies photosynthesis, and the amplified photosynthesis further accelerates the growth of leaves). Consequently, a linearity was found between cumulative canopy net photosynthesis (ΣAc) and LAI, implying that throughout the growth period, a fixed proportion of dry matter was partitioned to the leaves and that the leaf area was expanded in proportion to the partitioned dry matter. This linearity between ΣAc and LAI also suggests that growth of a leafy vegetable canopy can be predicted from canopy photosynthesis..
2. Koichi Nomura, Akihiro Takada, Hirosato Kunishige, Yukio Ozaki, Takashi Okayasu, Daisuke Yasutake, Masaharu Kitano, Long-term and continuous measurement of canopy photosynthesis and growth of spinach, Environmental Control in Biology, 10.2525/ecb.58.21, 58, 2, 21-29, 2020.01, [URL], To understand long-term association between canopy-scale photosynthesis and growth, we continuously and simultaneously measured the net photosynthetic rate (Ac) and leaf area index (LAI) of a spinach canopy from transplantation to harvesting. This long-term measurement was enabled by combining an open-type flux chamber method and image analysis of top-of-view canopy photographs. The photosynthetic photon flux density (PPFD) was the major determinant of Ac during a short-term period, but the change in Ac was significantly amplified by an increase in LAI during a long-term period. LAI, measured with reliable accuracy from gap fractions (projected non-leaf areas) of top-of-view photographs, increased exponentially through the growth period. These results indicate a positive feedback loop between photosynthesis and growth (i.e., the growth of leaves amplifies photosynthesis, and the amplified photosynthesis further accelerates the growth of leaves). Consequently, a linearity was found between cumulative canopy net photosynthesis (ΣAc) and LAI, implying that throughout the growth period, a fixed proportion of dry matter was partitioned to the leaves and that the leaf area was expanded in proportion to the partitioned dry matter. This linearity between ΣAc and LAI also suggests that growth of a leafy vegetable canopy can be predicted from canopy photosynthesis..
3. Aulia Rizkiana, Andri Prima Nugroho, Muhammad Abiyyu Irfan, Lilik Sutiarso, Takashi Okayasu, Crop growth prediction model at vegetative phase to support the precision agriculture application in plant factory, International Conference on Science and Applied Science 2019, ICSAS 2019
International Conference on Science and Applied Science, ICSAS 2019
, 10.1063/1.5141717, 2019.12, [URL], Plant factory is an extensive cultivation that produce vegetable under a controllable environment. The concept of Precision Agriculture has been introduced to enhance the plant factory production by monitoring of crop growth intensively. Crop growth can be estimated using a mathematical model to determine the state of the plant during the growth period. However, the application of a crop growth model in plant factory has several challenges because every plant has a specific model to be observed. The objective of this study was to construct a crop growth prediction model for vegetative development phase. The activity covers the development of mathematical model and model validation using Chili (Capsicum frutescens) as a preliminary experiment. Four samples (S1, S2, S3, S4) of Chili with age of five weeks after planting were used and measured daily for 30 days to get the actual height (cm). Three crop height observation data set (S1, S1, S3), were used to develop a mathematical model and the rest dataset was for model validation and evaluation. Linear and polynomial model were applied to obtain the appropriate prediction. The model was validated and evaluated using the Root Mean Squared Error (RMSE) and Mean Absolute Percentage Error (MAPE). As a result, Determination coefficient (R2) of the Linear model was 0.9667, and the RMSE was 2.16; The Polynomial model shows R2 0.98755, and RMSE RMSE 1.68. The result of the model that is suitable for the Chili crop during the vegetative phase is the polynomial model with error rate of 1,68%..
4. Dian Fatmawati, Andri Prima Nugroho, Arifin Widiyatmoko, Lilik Sutiarso, Takashi Okayasu, Design and performance evaluation of multi-camera for continuous plant motion monitoring system, International Conference on Science and Applied Science 2019, ICSAS 2019
International Conference on Science and Applied Science, ICSAS 2019
, 10.1063/1.5141716, 2019.12, [URL], Circadian rhythm is a biological rhythm that has a period of 24 hours. Leaf movement is one of physical indicator that commonly used to detect the circadian rhythms in the plant. In its application, it is required to design a plant motion monitoring system that can work automatically and continuously to estimate the period of plant motion and quantify the circadian rhythm. Generally, a plant monitoring system uses a top view projection to monitor plant activity. To extend its functionality, the side view projection was also important to monitor the plant behavior from a horizontal point of view. The objective of this study was to design and evaluate the performance of the Top and Side view projection as multi-camera for continuous plant motion monitoring system. The system composed of two IR LED cameras with Top and Side view projection and connected to the microcomputer (Raspberry Pi3 B+). The data were analyzed by Optical Flow method using OpenCV Library applying Shi-Tomasi and Lucas Kanade. Estimation of circadian rhythms was using the FFT (Fast Fourier Transform) method. The multi-camera system was evaluated to monitor the motion of Chili (Capsicum annum L.) by observing the time series of circadian rhythm, Period, Amplitude, and Phase. As a result, the system could be used to monitor the circadian rhythm for both Top and Side view projection. The Frequency and Period have the same value 0,00001157 and 24-hour. The Top view projection has higher amplitude means, for the same object motion it could represent clear motion..
5. Anggit Wijanarko, Andri Prima Nugroho, Lilik Sutiarso, Takashi Okayasu, Development of mobile RoboVision with stereo camera for automatic crop growth monitoring in plant factory, International Conference on Science and Applied Science 2019, ICSAS 2019
International Conference on Science and Applied Science, ICSAS 2019
, 10.1063/1.5141713, 2019.12, [URL], Plant Factory is a large-scale vegetable production method with limited, closed, and controlled space. This system is endeavored to support the sustainability of agricultural production system by applying the concept of precision agriculture. This concept is implemented to observe plant growth effectively and efficiently. Currently, in the conventional way monitoring carried out one by one, using the computer vision technology will help accelerate plant growth monitoring in the Plant Factory. However, in the application in a Plant Factory, it requires many cameras to be used for growth monitoring for each crop to support the precise measurement. So, it is necessary to have a system that supports the mobility of the camera module inside the plant factory. The objective of this study was to design the Mobile RoboVision using the stereo camera for automatic Crop Growth Monitoring. The system consists of three modules: Stereo camera positioning system using M1 Computer Numerical Control (1000mm x 1000mm of size) equipped with x and y motor for flexible movement; Image acquisition system using Raspberry Pi B+ as microcomputer unit installed Stereo Camera standard with quad IR Illuminator and sensors; Data collection system using Cloud Storage. The camera positioning system manages the position of the camera module to stop in every crop in specified coordinate C1..n = {(x1, y1), (x2, y2), ..(xn, yn)} and capture stereo images automatically. The captured image will be managed in a data collection system using Cloud System to provide flexible and convenient access for further analysis..
6. Siti Maghfiroh, Andri Prima Nugroho, Adetya Raya Putra, Lilik Sutiarso, Takashi Okayasu, Implementation of leaf motion monitoring system to study plant behavior with variations of the lighting interval in Capsicum annuum L., International Conference on Science and Applied Science 2019, ICSAS 2019
International Conference on Science and Applied Science, ICSAS 2019
, 10.1063/1.5141715, 2019.12, [URL], Circadian rhythm is a biological rhythm in a plant that has a 24-hour period, which affects the plant activities, such as metabolism processes, physiology processes, and plant behavior. Generally, Circadian rhythm has two factors affecting the synchronizing the biological clock: Light and temperature cycle. In our previous studies, plant motion monitoring systems based on leaf movement have been developed to determine the circadian rhythms of a regular plant under the normal condition. However, the performance of the system to monitor the plant rhythm under abnormal conditions relating to the biological clock, lighting interval treatment, does not establish yet. The objective of this study was to implement a plant motion monitoring system to study plant behavior with 16-hour and 12-hour lighting interval treatment. The plant's motion of Chili (Capsicum annum L.) was observed in a growth chamber equipped with an infrared camera and raspberry pi, which is used to take pictures continuously at certain intervals using top projection view. Periode of circadian rhythms phase, the amplitude of the plant were analyzed and compared. As a result, plant motion monitoring system could be used to monitor the circadian rhythm on Chili (Capsicum annum L.) with the variation of lighting interval (12-h and 16-h). The amplitude of 16-hour lighting has higher and the period shift indicated late oscilation comparing the 12-hour lighting. The higher amplitude and late in oscilation is accordance with previous studies that environmental cues, such as light, can reset the clock and can also affect the rhythm output clock..
7. A. P. Nugroho, L. Sutiarso, T. Okayasu, Appropriate adaptation of precision agriculture technology in open field cultivation in tropics, 3rd International Symposium on Agricultural and Biosystem Engineering, ISABE 2019
IOP Conference Series: Earth and Environmental Science
, 10.1088/1755-1315/355/1/012028, 355, 1, 2019.11, [URL], Tropical agriculture production is profoundly affected by the uncontrollable environmental condition. To obtain good agricultural products, farmers manage their farm to fit with the variation of weather and season. The farming managements are generally determined according to farmers personal knowledge, gained from the long-term experience from preceding years. Nowadays, climate change intensifies unpredictable weather and its unstable distribution. Consequently, conventional farming management considering the climate change factor should be considered. The farming management should face the dynamic change of weather condition as well as improve the farmer's knowledge towards the implementation of precision agriculture approach. The objective of this study was to introduce an appropriate adaptation of precision agriculture technology by the utilization of information and communication technology (ICT) to improve conventional farming management in tropical agriculture production. The framework is implementing cloud technology as a backbone, which can be extended with various knowledge such as data science, plant biology, plant physiology, biophysical, and biomechanical. The appropriate adaptation of precision agriculture represented by the improvement of the conventional farming method using the technological aspect by fostering their knowledge to adopt modern agriculture empowered with Information and Communication Technology (ICT). Learning process from data-information-knowledge on the application of precision agriculture will be documented at the PA Knowledge Management System..
8. M. S. Hidayat, A. P. Nugroho, L. Sutiarso, T. Okayasu, Development of environmental monitoring systems based on LoRa with cloud integration for rural area, 3rd International Symposium on Agricultural and Biosystem Engineering, ISABE 2019
IOP Conference Series: Earth and Environmental Science
, 10.1088/1755-1315/355/1/012010, 355, 1, 2019.11, [URL], Wireless Sensor Network (WSN) is widely used in field environmental monitoring recently, because of its ease of use and being able to simplify the complexity installation in real application. Indonesia is an agricultural country with more than 16.5 million of farming land, most of the farming land is located in a rural area. The problems on the implementation of IoT-based environmental monitoring system in a rural area is the limited signal and energy. Accordingly, the objective of this study was to develop an Environmental Monitoring System based on LoRa in a rural area with the implementation of the Local Management Subsystem (LMS) and Global Management Subsystem (GMS) framework to optimize the existing development of the Environmental Monitoring System with focused on optimum distance by measuring the RSSI, signal strength and packet loss. The research was conducted in Bulaksumur Universitas Gadjah Mada, Yogyakarta, with four zones and various obstacles. As the result, Zone D with line of sight was the best result for getting the affordable distance for data transmission. This Zone can reach over 800 m distance with only 20% packet loss..
9. 木次谷 一平, 伊藤壱記, 中村貴久, 石川達也, 岡安崇史, 下負荷面モデルを用いた繰返し載荷を受けた道床バラストの弾塑性変形挙動の検討, 土木学会論文集E1(舗装工学), 75(2), I_105-I_113, 2019.11.
10. Wu, ZB., Xie, B., Li, Z., Mitsuoka, M., Inoue, E., Okayasu, T., Hirai, Y. , dSPACE based Hardware in the loop Testing Platform for Powertrain Management Unit of Electric Tractor, Journal of the Faculty of Agriculture Kyushu University, 64(2), 309-317, 2019.10.
11. Zhongbin Wu, Bin Xie, Zhen Li, Ruijuan Chi, Zhiyong Ren, Yuefeng Du, Eiji Inoue, Mitsuoka Muneshi, Takashi Okayasu, Hirai Yasumaru, Modelling and verification of driving torque management for electric tractor
Dual-mode driving intention interpretation with torque demand restriction, Biosystems Engineering, 10.1016/j.biosystemseng.2019.04.002, 182, 65-83, 2019.06, [URL], A torque management model (TMM) focused on the close matching of driving requirements and operating conditions for electric tractors was developed. The TMM used the accelerator pedal output signal to establish the torque demand to adapt for two conditions – field traction and road driving. Further, the TMM uses the limitations of a time-based torque ramp, maximum motor torque at the current speed, and battery state of charge. To verify the performance of the TMM, a tractor control unit (TCU) to support the TMM was designed, and a test bench comprising both driving and loading devices was built. The bench provided the TMM/TCU with the necessary operating states needed as inputs to determine the torque demand. Experiments were performed under five specific manoeuvring cases. The test results showed that the TMM was capable of accurately converting pedal manipulations into torque demands both in the field traction and road driving conditions. The torque changes during testing were properly smoothed by limiting the rising and falling time of the target torque, which was favourable for eliminating impacts due to torque fluctuations. Overloading operations that would occur in case of excessive torque request were avoided by the torque capacity limitation both in the field traction and road acceleration tests. When the bus voltage was deliberately adjusted below the alarm threshold, the TMM could scale down the torque demand in real time according to the deviation between the actual voltage and the threshold, and therefore, it always kept the voltage above the safe level..
12. Zhongbin Wu, Bin Xie, Zhen Li, Ruijuan Chi, Zhiyong Ren, Yuefeng Du, Eiji Inoue, Muneshi Mitsuoka, Takashi Okayasu, Yasumaru Hirai, Modelling and verification of driving torque management for electric tractor
Dual-mode driving intention interpretation with torque demand restriction, Biosystems Engineering, 10.1016/j.biosystemseng.2019.04.002, 182, 65-83, 2019.06, [URL], A torque management model (TMM) focused on the close matching of driving requirements and operating conditions for electric tractors was developed. The TMM used the accelerator pedal output signal to establish the torque demand to adapt for two conditions – field traction and road driving. Further, the TMM uses the limitations of a time-based torque ramp, maximum motor torque at the current speed, and battery state of charge. To verify the performance of the TMM, a tractor control unit (TCU) to support the TMM was designed, and a test bench comprising both driving and loading devices was built. The bench provided the TMM/TCU with the necessary operating states needed as inputs to determine the torque demand. Experiments were performed under five specific manoeuvring cases. The test results showed that the TMM was capable of accurately converting pedal manipulations into torque demands both in the field traction and road driving conditions. The torque changes during testing were properly smoothed by limiting the rising and falling time of the target torque, which was favourable for eliminating impacts due to torque fluctuations. Overloading operations that would occur in case of excessive torque request were avoided by the torque capacity limitation both in the field traction and road acceleration tests. When the bus voltage was deliberately adjusted below the alarm threshold, the TMM could scale down the torque demand in real time according to the deviation between the actual voltage and the threshold, and therefore, it always kept the voltage above the safe level..
13. Rin Ichiro Taniguchi, Daisaku Arita, Atsushi Shimada, Masanori Yamada, Yoshiko Goda, Ryota Yamamoto, Takashi Okayasu, Integrated contextual learning environments with sensor network for crop cultivation education
Concept and design, 16th International Conference on Cognition and Exploratory Learning in Digital Age, CELDA 2019
16th International Conference on Cognition and Exploratory Learning in Digital Age, CELDA 2019
, 242-248, 2019.01, This paper presents an outline of our project, in which we develop an observation framework for integrating lecture and contextual learning in the field of crop cultivation. Specifically, we will use multi sensing of learners' activities in classrooms, and contextual learning in fieldwork, farm planting, and farming environments. The motivation for our project is twofold: First, crop cultivation provides a powerful illustration of educational technology. It requires both explicit knowledge (from lectures) and implicit knowledge (from contextual learning outside of class). Second, from a practical viewpoint, the number of Japanese farmers is shrinking due to low income and to aging population. Thus, in order to maintain crop yields, farming skills must be transferred efficiently to novice farm workers. Herein, the major features of our framework will be described..
14. Yoshiki Hashimoto, Daisaku Arita, Atsushi Shimada, Takashi Yoshinaga, Takashi Okayasu, Hideaki Uchiyama, Rin-Ichiro Taniguchi, Yield visualization based on farm work information measured by smart devices, Sensors (Switzerland), 10.3390/s18113906, 18, 11, 2018.11, [URL], This paper proposes a new approach to visualizing spatial variation of plant status in a tomato greenhouse based on farm work information operated by laborers. Farm work information consists of a farm laborer’s position and action. A farm laborer’s position is estimated based on radio wave strength measured by using a smartphone carried by the farm laborer and Bluetooth beacons placed in the greenhouse. A farm laborer’s action is recognized based on motion data measured by using smartwatches worn on both wrists of the farm laborer. As experiment, harvesting information operated by one farm laborer in a part of a tomato greenhouse is obtained, and the spatial distribution of yields in the experimental field, called a harvesting map, is visualized. The mean absolute error of the number of harvested tomatoes in each small section of the experimental field is 0.35. An interview with the farm manager shows that the harvesting map is useful for intuitively grasping the states of the greenhouse..
15. Yoshiki Hashimoto, Daisaku Arita, Atsushi Shimada, Takashi Yoshinaga, Takashi Okayasu, Hideaki Uchiyama, Rin Ichiro Taniguchi, Yield visualization based on farm work information measured by smart devices, Sensors (Switzerland), 10.3390/s18113906, 18, 11, 2018.11, [URL], This paper proposes a new approach to visualizing spatial variation of plant status in a tomato greenhouse based on farm work information operated by laborers. Farm work information consists of a farm laborer’s position and action. A farm laborer’s position is estimated based on radio wave strength measured by using a smartphone carried by the farm laborer and Bluetooth beacons placed in the greenhouse. A farm laborer’s action is recognized based on motion data measured by using smartwatches worn on both wrists of the farm laborer. As experiment, harvesting information operated by one farm laborer in a part of a tomato greenhouse is obtained, and the spatial distribution of yields in the experimental field, called a harvesting map, is visualized. The mean absolute error of the number of harvested tomatoes in each small section of the experimental field is 0.35. An interview with the farm manager shows that the harvesting map is useful for intuitively grasping the states of the greenhouse..
16. T. Okayasu, D. Arita, T. Yoshinaga, A. Shimada, R. Taniguchi, E. Inoue, Y. Hirai, and M. Mitsuoka, Development of plant phenotyping platform using affordable devices and sensors, Proc. AFITA/WCCA2018
, 4 pages, CD-ROM, 2018.10.
17. Nugroho A.P., Sutiarso, L., Masithoh, R.E., Okayasu, T., Development of Plant Motion Monitoring System to Study The Circadian Rhythms Based on Leaf Motion Implementing the Optical Flow Method, Proceedings of the 9th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB), 1-7, 2018.05.
18. Okayasu, T., Arita, D., Yoshinaga, T., Taniguchi, R., Inoue, E., Hirai, Y., Mitsuoka, M., Development of Monorail-type Mobile Robot for Field Environment and Plant Status Monitoring, Proceedings of the 9th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB), 1-6, 2018.05.
19. Yoshizak, R., Hirai, Y., Mitsuoka, M., Inagaki, S., Inoue, E., Okayasu, T., Relationships between Mass and Porosity of Rough Rice Piled in a Combine Grain Tank, Proceedings of the 9th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB), 1-6, 2018.05.
20. Ibrahim, M.N.R., Okayasu, T., Yoshimura, A., Yamagata, Y., Furuya, N, Inoue, E., Hirai, Y., Mitsuoka, M., Early Disease Detection of Bacterial Leaf Blight on Rice Plant by using Hyperspectral Imaging, Proceedings of the 9th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB), 1-5, 2018.05.
21. Shin, S., Inoue, E., Mitsuoka, M., Okayasu, T., Hirai, Y., Matsui, M., Investigation of Terrain Slope Information and Tractor Driving Simulation on Reconstructed Ground, Proceedings of the 9th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB), 1-5, 2018.05.
22. Borin Khem, Hirai Yasumaru, Takeo Yamakawa, Yuki Mori, Eiji Inoue, Takashi Okayasu, Mitsuoka Muneshi, Effects of different application methods of fertilizer and manure on soil chemical properties and yield in whole crop rice cultivation, Soil Science and Plant Nutrition, 10.1080/00380768.2018.1443399, 64, 3, 406-414, 2018.05, [URL], Whole crop rice (WCR) is expected to establish a cultivation method using manure produced from animal wastes. Meanwhile, application methods of fertilizer and manure in the WCR cultivation are affected by availability of manure, available time for its application, and field drainage, and low market price of WCR. This raises concerns about soil fertility deterioration and yield reduction in the WCR cultivation. The objectives of this study were to investigate how different application methods of fertilizer and manure affected soil chemical properties and yield in the WCR cultivation. Field surveys were conducted in 2013 and 2014 at 10 fields cultivated by five different farmers in the Itoshima region, Fukuoka Prefecture, Japan. The surveyed fields included two application methods of manure (M) alone and chemical fertilizer (CF) alone. Clay plus silt content was significantly correlated with total nitrogen (TN), total phosphorus (TP), and exchangeable potassium (Exch. K), which indicated that soil texture partly contributed to the variations of these soil chemical properties. Meanwhile, clear gaps of TN, TP, Exch. K, K saturation degree, and available N between CF and M at around 40% of clay plus silt content strongly suggested that manure application contributed to increases in the soil chemical properties. Yearly differences of available N had relatively large negative values in CF fields. This result suggested a possible decrease in mineralizable part of soil TN in the WCR cultivation with CF alone, which needs to be clarified through long-term study. Significant relationships between potential N supply and straw weight (r = 0.698, p < 0.05 for 2013; r = 0.873, p < 0.01 for 2014) or yield of whole crop (r = 0.852, p < 0.01 for 2014) indicated that N mineralized from soil, which was enhanced by manure application, increased straw weight, resulting in an increase in yield of whole crop. However, excessive amounts of manure applied in surveyed fields can cause groundwater and surface water pollution. Thus, nutrient balances in a paddy field need to be analyzed further to determine an appropriate application amount of manure..
23. Wan Soo Kim, Yeon Soo Kim, Yong Joo Kim, Chang Hyun Choi, Eiji Inoue, Takashi Okayasu, Analysis of the load of a transplanter PTO shaft based on the planting distance, Journal of the Faculty of Agriculture, Kyushu University, 63, 1, 97-102, 2018.02, The purpose of this study was to analyze the load of a transplanter PTO shaft during transplanting operations with respect to planting distances. To measure the loads on the PTO shaft of a transplanter, a load measurement system was constructed using a torque sensor and an embedded system. Field experiments were conducted at planting distances of 26,35,43, and 80 cm in a field with similar soil conditions. The load measured was converted from the time domain to the frequency domain using the rain-flow counting and SWT methods. The damage level of the transplanter to the working load with respect to the planting distance was calculated using Miner's rule, and the damage level was represented by ratio of the damage sum to the smallest damage sum among the planting distances. The damage level was increased by 199,493, and 708% when the planting distance gradually decreased from 80 to 43,35, and 26 cm, respectively. The results show that a shorter planting distance has a stronger effect on the transplanter PTO shaft than a longer planting distance. Therefore, it is known that transplanter PTO shafts should be designed while considering working loads with respect to planting distance..
24. Nur Iman Muztahidin, Daisuke Yasutake, Kota Hidaka, Yuta Miyoshi, Ayami Yoneda, Koyo Nagao, Kitano Masaharu, Takashi Okayasu, Characteristics of low-light LED as supplemental lighting and its effects on leaf gas exchange in strawberry, Journal of the Faculty of Agriculture, Kyushu University, 63, 1, 139-142, 2018.02, The aim of this study was to analyze the fundamental lighting characteristics (spectrum distribution and light intensity) of a low-light LED unit and its effect on gas exchange in strawberry leaves. This unit was newly developed to provide low-cost supplemental lighting for greenhouses. The low-light LED unit was made using 24 LED module chips, each of which were 1 m in length and 43.2 W. The electricity consumption of this unit was only 55% of that of the high-light LED previously reported by Hidaka et al. (2013). The spectrum characteristics of low-light LED were measured using a portable spectro-radiometer. The photosynthetic photon flux density (PPFD) was measured using a photon sensor, and its distribution was measured at five different heights from a reference plane (110 cm x 150 cm). Gas exchange in strawberry leaves under low-light LED (Low LED treatment) supplemental lighting and no lighting (Control treatment) were measured using a leaf chamber system. The results demonstrated that the spectrum distribution patterns of the low-light LED and the high-light LED were similar; we found that the relative light intensity of both LEDs peaked once near a wavelength of 450 nm and again near a wavelength of 550 nm. The PPFD and its horizontal distribution showed that, as the height of the light source increased, the PPFD and lighting regions decreased and increased, respectively. On the other hand, as the height of 20 cm, PPFD under supplemental lighting with the low-light LED increased by 2.1 times than natural condition. As a result, stomatal conductance and transpiration rate increased by 1.5 times and 1.2 times, respectively; further photosynthetic rate increased by 2.2 times. Thus, the low-light LED was demonstrated to have suitable wavelength for crop production. Furthermore, applying supplemental lighting with the low-light LED significantly improved light intensity and accelerated photosynthesis in strawberry..
25. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Zhongxiang Zhu, Zhenghe Song, Enrong Mao, Identification of configurational effectiveness on improvement of tractor stability on uneven roads, Journal of the Faculty of Agriculture, Kyushu University, 63, 1, 113-117, 2018.02, It has been identified that tractor stability can be affected by multiple factors, including configurational and environmental parameters. To improve tractor stability and enhance the resistance of the tractorimplement system to exterior disturbs, three tractor physical parameters were selected as the key control factors to examine their statistical significances and to find out the corresponding desired levels. In this study, a scaled experimental system consisting of a scaled tractor-implement model, force-sensing system, random road surfaces was developed. The tractor was operated to travel forward passing over two classes of rough road. Various tractor configuration patterns were assigned following the L27 orthogonal array according to the Taguchi design of experiment. Adopting the concept of lateral-load transfer ratio, the output voltage signals of the force sensing resistors were calculated for the stability indexes basing on tractor front and rear axles. Results showed that the type of tractor front tire and the ballast weight significantly varied the ground contact condition of the front tires, while the rear track width of the tractor predominantly determined the rear-axle-based vehicle stability..
26. Yeon Ju Jo, Young Sun Kang, Ju Seok Nam, Jung Seob Choe, Eiji Inoue, Takashi Okayasu, Dae Cheol Kim, Performance analysis for a card cleaner type separating system of pepper harvester, Journal of the Faculty of Agriculture, Kyushu University, 63, 1, 103-111, 2018.02, This study conducted a factorial experiment with an experimental bench to analyze the separation performance of a card cleaner type separating system of pepper harvesters. The factors used for this study were the card arrangement (inline and staggered), slope angle (5° and 15°), and rotational speed (35, 50, and 65 rpm) of the card cleaner. The separation efficiency of peppers was influenced by the slope and rotational speed of the card cleaner in both types of card arrangement. In the inline arrangement, the mixing ratio of foreign materials was influenced by slope angle but not influenced by the rotational speed of the card cleaner. In the staggered arrangement, the mixing ratio of foreign materials was influenced by slope angle and the rotational speed of the card cleaner. The high separation efficiency in the staggered arrangement was obtained under the conditions of a slope of 5° and a rotational speed of 50 rpm. However, the mixing ratio of foreign materials was also high in this condition. The high separation efficiency in the inline arrangement was obtained under the conditions of a slope of 15° and a rotational speed of 50 rpm, and the mixing ratio of foreign materials was relatively low in this condition. Thus, the inline arrangement with a slope angle of 15°was recommended for a separating system of self-propelled pepper harvesters..
27. Ken ichiro Yasuba, Hidehito Kurosaki, Takehiko Hoshi, Takashi Okayasu, Yoshiyuki Tanaka, Tanjuro Goto, Yuichi Yoshida, Development of program library using an open-source hardware for implementation of low-cost greenhouse environmental control system, Environmental Control in Biology, 10.2525/ecb.56.107, 56, 3, 107-112, 2018.01, [URL], A program library for use on open-source hardware was developed in order to construct a low-cost environmental control system for greenhouses. The library facilitated the development of environmental sensing and control devices that conform to the protocols of the Ubiquitous Environment Control System (UECS). The open-source hardware used was the “Arduino Ethernet” and the “Arduino Mega 2560 with Ethernet Shield” microcontroller boards. UECS is a system for controlling greenhouse environments that communicates information via a local area network, and devices utilizing the library that we developed can perform the UECS defined communication tasks automatically. With the help of this library, device developers no longer need to program the communications aspects of the device and can concentrate on programming setting and control logic of the device. The library occupies about 29 kilobytes of the read only memory area of the target board. The library and associated open-source microcontroller boards are powerful tools for developing low-cost environmental control systems..
28. Okayasu, T., Nugroho, A.P., Sakai, A., Arita, D., Yoshinaga, T., Taniguchi, R., Horimoto, M., Inoue, E., Hirai, Y., Mitsuoka, M., Affordable Field Environmental Monitoring and Plant Growth Measurement System for Smart Agriculture, 11th International Conference on Sensing Technology (ICST), 10.1109/ICSensT.2017.8304486, 1-4, 2017.12.
29. Uchiyama, H., Sakurai, S., Hashimoto, Y., Hanasaki, A., Arita, D., Okayasu, T., Shimada, A., Taniguchi R., Sensing technologies for advanced smart agricultural systems, 11th International Conference on Sensing Technology (ICST), 10.1109/ICSensT.2017.8304451, 1-4, 2017.12.
30. Uchiyama, H., Sakurai, S., Mishima, M., Arita, D., Okayasu, T., Shimada, A., Taniguchi, R., An Easy-to-Setup 3D Phenotyping Platform for KOMATSUNA Dataset, 2017 IEEE International Conference on Computer Vision Workshops (ICCVW), 10.1109/ICCVW.2017.239, 2038 - 2045, 2017.10.
31. Hirai Yasumaru, K. Tanaka, T. Nakanishi, T. Shikanai, Eiji Inoue, Takashi Okayasu, Mitsuoka Muneshi, Measurement accuracy of the area of combine-harvested field sections corresponding to a truckload of grain received at a grain elevator, Engineering in Agriculture, Environment and Food, 10.1016/j.eaef.2017.05.001, 10, 4, 272-281, 2017.10, [URL], Measuring the area of combine-harvested field sections corresponding to a truckload of grain received at a grain elevator (LHA: load harvest area) allows the estimation of brown rice yield. The objective of this study was to evaluate the accuracy of LHA measured based on combine movement traces when the traces were recorded by a GPS or a GPS + Quasi-Zenith Satellite System (QZSS) receiver. For the measurements using a GPS receiver, the mean and standard deviation of relative errors of LHA were 4.7% and 8.1%. The center of the relative error distribution shifted toward positive because positioning errors of a GPS receiver shifted outer edges of harvested sections outward and resulted in measuring larger harvested area than a true value. For the measurements using a GPS + QZSS receiver, the mean and standard deviation of relative errors of LHA were 0.5% and 4.8%. The center of the relative error distribution was around 0% for its better positioning accuracy. The relative errors of LHA tended to be large when an LHA was measured from a field section where only the outer-part of a field is harvested or several small harvested sections. These cases of LHA measurements increased the sum of the perimeter of harvested sections and resulted in deteriorating the measurement accuracy. This result indicated that measurement accuracy of LHA can be further improved by correcting error, which can be estimated based on positioning errors and the perimeter of harvested sections..
32. Jung Seob Choe, Kohei Takata, Eiji Inoue, Tae Wook Kim, Mitsuoka Muneshi, Takashi Okayasu, Hirai Yasumaru, Judging the abnormalities of agricultural machinery by using Mahalanobis' distance, Journal of the Faculty of Agriculture, Kyushu University, 62, 2, 469-476, 2017.09, This study calculated the Mahalanobis' distance, which is a multidimensional space distance with correlations, from the time-series data of 3-axis translational acceleration and 3-axis rotational angular speed, and examined whether this could be used in judging the abnormalities of the agricultural machineries. As the result, using the Mahalanobis' distance to determine the abnormality of the data was not possible for the changes in not-so-big behaviors, such as turning and temporary stop, but determining the abnormality of the data using the Mahalanobis' distance was clearly possible for sudden changes to the operating status of the equipment, such as a roll over and passing obstacles through an experiment using the model car. We hypothesized in the beginning that the distribution of the Mahalanobis' distance at the signal space could be separated with the distribution of the Mahalanobis' distance at the unit space. However, unless there is a large-scale change to the behavior, such as a roll over, etc., complete separation is difficult in reality, and we determined realistically that conducting the abnormality determination from the significant difference viewpoint by placing a threshold value to the normalized distribution of the Mahalanobis' distance at the unit space is possible..
33. Takashi Okayasu, Andri Prima Nugroho, Daisaku Arita, Takashi Yoshinaga, Yoshiki Hashimoto, Rin ichiro Tachiguchi, Sensing and visualization in agriculture with affordable smart devices, Smart Sensors at the IoT Frontier, 10.1007/978-3-319-55345-0_12, 299-325, 2017.05, [URL].
34. Koichiro Fukami, Toshifumi Mukunoki, Keiko Nakano, Naoki Matsuo, Takashi Okayasu, Water leakage control by using vibratory roller on a dry-seeded rice field in southwestern Japan, Soil and Tillage Research, 10.1016/j.still.2016.09.011, 166, 138-146, 2017.03, [URL], Dry-seeded rice cultivation is an effective low-cost cultivation method in Japan, but preventing water leakage from cultivated rice fields remains a challenge. Here we assessed the efficiency of using a vibratory roller in a dry-seeded rice field for preventing water leakage. The tests were conducted at two different soil-water contents (WC: 32 and 39%) before roller compaction. We measured the acceleration response of the vibrating roller by using a micro-electro mechanical system (MEMS) accelerometer, and we determined the volume of water leakage from the field by using a rapid leakage capacity tester. We analyzed the changes in the soil structure by using a micro-focused X-ray CT scanner. We analyzed all of the resulting data to identify any correlation. We observed that water leakage from the field was sufficiently prevented when prior to roller compaction, soil moisture content was 39%. The shape of the soil pores that could efficiently prevent water leakage was flatter than that of the inefficiently compacted soil. In addition, the total porosity decreased, but the small-sized pore fraction increased. The vibration acceleration of the roller significantly increased with the decrease in the volume of water leakage. Thus, in addition to assessing the efficiency of vibratory rollers in reducing water leakage, our data suggest that it is to some extent possible to estimate the water leakage prevention effect from the acceleration response of a vibrating roller..
35. Mansur Ahmed, Akinori Ozaki, Dipok K. Choudhury, Kazuo Ogata, Shoichi Ito, Ikuo Miyajima, Ashir Ahmed, Takashi Okayasu, Amin Nayeen Al, Chemical Free Vegetable Cultivation and Outcomes in Winter Season in Bangladesh
A case study on BOP farmers in five districts, Journal of the Faculty of Agriculture, Kyushu University, 62, 1, 255-262, 2017.02, In Bangladesh the demand of chemical free vegetables is increasing due to health hazards of conventional vegetables. However, the awareness of the farmers and supply of such vegetables are not sufficient. In this research, therefore, we focused on why agrochemical free vegetable production including marketing has been underdeveloped in Bangladesh as a growing business compared to conventional vegetable production. In order to collect the information, which can argue these reality of chemical free vegetable production, distribution and marketing in Bangladesh, we especially focused on widely cultivated winter vegetables such as cabbage, cauliflower and tomato. Data were collected targeting the activities of SENSE (Support to establish a new society of BOP farmers by using the power of ICT) project regarding production and marketing. The results indicated that the production of chemical free cauliflower and tomato were substandard compare to the cabbage. The reasons for getting substandard production were unavailability of proper production inputs such as appropriate organic pesticides, quality compost and lack of timely execution of the farming activities. Moreover, the selling results indicated that farmers got higher income from tomato compare to cabbage and cauliflower. Additionally, revenue (per kg) of the products sold in Dhaka market was more than the local markets. The differences of revenue (per kg) between Dhaka and locally sold cabbage, cauliflower and tomato were BDT 6.02, BDT 6.63 and BDT 10.22, respectively. However, the average selling percentage of cabbage, cauliflower and tomato in Dhaka market (10.06%) and local market (89.94%) indicated that chemical free vegetable production had high potential by selling more products in Dhaka market for high income generation of the resource poor farmers..
36. Mansur Ahmed, Akinori Ozaki, Dipok K. Choudhury, Kazuo Ogata, Shoichi Ito, Ikuo Miyajima, Ashir Uddin Ahmed, Takashi Okayasu, Nayeen Aamin, Chemical free vegetable cultivation and outcomes in winter season in Bangladesh
A case study on BOP farmers in five districts, Journal of the Faculty of Agriculture, Kyushu University, 62, 1, 255-262, 2017.02, In Bangladesh the demand of chemical free vegetables is increasing due to health hazards of conventional vegetables. However, the awareness of the farmers and supply of such vegetables are not sufficient. In this research, therefore, we focused on why agrochemical free vegetable production including marketing has been underdeveloped in Bangladesh as a growing business compared to conventional vegetable production. In order to collect the information, which can argue these reality of chemical free vegetable production, distribution and marketing in Bangladesh, we especially focused on widely cultivated winter vegetables such as cabbage, cauliflower and tomato. Data were collected targeting the activities of SENSE (Support to establish a new society of BOP farmers by using the power of ICT) project regarding production and marketing. The results indicated that the production of chemical free cauliflower and tomato were substandard compare to the cabbage. The reasons for getting substandard production were unavailability of proper production inputs such as appropriate organic pesticides, quality compost and lack of timely execution of the farming activities. Moreover, the selling results indicated that farmers got higher income from tomato compare to cabbage and cauliflower. Additionally, revenue (per kg) of the products sold in Dhaka market was more than the local markets. The differences of revenue (per kg) between Dhaka and locally sold cabbage, cauliflower and tomato were BDT 6.02, BDT 6.63 and BDT 10.22, respectively. However, the average selling percentage of cabbage, cauliflower and tomato in Dhaka market (10.06%) and local market (89.94%) indicated that chemical free vegetable production had high potential by selling more products in Dhaka market for high income generation of the resource poor farmers..
37. Dae Hyun Lee, Yong Joo Kim, Chang Hyun Choi, Sun Ok Chung, Eiji Inoue, Takashi Okayasu, Development of a parallel hybrid system for agricultural tractors, Journal of the Faculty of Agriculture, Kyushu University, 62, 1, 137-144, 2017.02, The purpose of this study was to develop parallel hybrid tractor. The hybrid tractor was constructed by adding major components of a hybrid driving system on a tractor. The tractor has 71 kW engine power and the major components included an EMG (electric motor/generator), an inverter, batteries, a battery management system (BMS), and a hybrid control unit (HCU). The hybrid tractor had three control modes: idle, power assist, and battery charge and it were determined by the workload which estimated by measuring engine rotational speed. Performance of the hybrid tractor was evaluated through the field tests of plowing. Performance tests were conducted by comparing the hybrid tractor and the conventional one, and one hybrid tractor was used for the experiment. The hybrid tractor used the hybrid system for the control of EMG, and the conventional tractor was driven by the engine not using the hybrid system. Performances of the hybrid tractor and the conventional tractor were similar at M2 which is low speed condition and it could work with low load, but the performance of the hybrid tractor was better than one of the conventional tractor at higher load condition (M3, M4). Fuel efficiency of the hybrid tractor at M2 was similar with the one of the conventional tractor, but it was lower at M3 and M4 than the one of the conventional tractor by 74%. Considering all results of this study, the developed parallel hybrid tractor is feasible to improve plowing performance of the conventional tractor..
38. Yuta Miyoshi, Kota Hidaka, Takashi Okayasu, Daisuke Yasutake, Kitano Masaharu, Application of the constant soil temperature layer for energy-saving control in the local environment of greenhouse crops II. Application to strawberry cultivation during the winter season, Environmental Control in Biology, 10.2525/ecb.55.37, 55, 1, 37-40, 2017.01, [URL], For stable year-round production of greenhouse crops with sustainability and high profitability, it is essential to establish a system that encompasses energy-saving and year-round environmental control via the application of renewable energy resources. One such renewable energy resource is the constant soil temperature layer, which is widespread and easily accessible in agricultural fields. However, owing to the low heat capacity and conductivity of media such as soil and air, heat exchange with the constant soil temperature layer has been considered insufficient for temperature control of the entire air volume inside a greenhouse. Therefore, we utilized a novel local temperature control system based on heat exchange between the constant soil temperature layer and the ambient air surrounding greenhouse crops. In the present study, we applied this system to the elevated bed system of strawberry crops with no-heating culture during the winter season. The system, that control the ambient air temperature of strawberry crops, increased fruits yield compared with no-heating, and was estimated 45% reduction of heating load to maintain 8°C or more..
39. Yuta Miyoshi, Tomomi Hidaka, Kota Hidaka, Takashi Okayasu, Daisuke Yasutake, Kitano Masaharu, Dynamics of photosynthate loading in strawberries affected by light condition on source leaves, Environmental Control in Biology, 10.2525/ecb.55.53, 55, 1, 53-58, 2017.01, [URL], In greenhouse production of strawberries (Fragaria×ananassa×Duch.) during winter season in Japan, unsuitable climate condition (low solar radiation, low temperature, etc.) for strawberry growth causes serious problems such as yield depression and low quality of fruits. For sustainable production with high profitability, it is keenly desired to establish a system for efficient environmental control based on physiological functions of crops. Translocation of photosynthate from leaves to fruits is a major physiological determinant for size and sugar content of strawberries. It is therefore essential to clarify the response of photosynthate loading to surrounding environment. In this study, we focused on light condition which strongly influences the photosynthesis, and analyzed effects of irradiation on dynamics of photosynthate loading. Furthermore, aiming at the estimation of dynamics of photostnthate loading in cultivation field, we simulated daily amount of photosynthate loading by kinetic model using a saturable Michaelis-Menten component in combination with an unsaturable component obeying first-order kinetics..
40. Yuta Miyoshi, Kota Hidaka, Takashi Okayasu, Daisuke Yasutake, Kitano Masaharu, Effects of local CO2 enrichment on strawberry cultivation during the winter season, Environmental Control in Biology, 10.2525/ecb.55.165, 55, 4, 165-170, 2017.01, [URL], In strawberry production, carbon dioxide (CO2) enrichment is widely used to promote crop photosynthesis and to improve growth and yield of strawberry fruits. However, a standard CO2 enrichment method has not been established clearly. For sustainable strawberry production with high profitability, it is essential to establish an efficient system for CO2 enrichment. Therefore, in this study, we newly propose a local CO2 enrichment system. The system enriches CO2 only ambient to strawberry crops, not a whole greenhouse, and thereby enables efficient control of CO2 concentration. We applied this system in a strawberry cultivation greenhouse with ventilating windows and examined the performance of system. During the daytime on clear days with opened greenhouse ventilation windows, the proposed system stabilized the ambient CO2 concentration to strawberry crops at 800 ppm. Furthermore, when the day after CO2 enrichment was begun, strawberry crop photosynthesis and photosynthate translocation from source leaves were promoted as the effects of short-term CO2 enrichment. Nevertheless, the yields and quality of fruits was not affected by the system. It is considered that long-term CO2 enrichment thickened source leaves and thereby caused down-regulation of photosynthesis. Further consideration will be needed on effect of long-term CO2 enrichment on physiological function of crops..
41. 星 岳彦,越智眞之助,松山智紀,安場健一郎,黒崎秀仁,岡安崇史, 温室環境計測機器のための低コスト相対湿度センサの耐候性評価, 農業情報研究, 25 (3) 79-85, 2016.10.
42. Andri Prima Nugroho, Takashi Okayasu, Masafumi Horimoto, Daisaku Arita, Takehiko Hoshi, Hidehito Kurosaki, Ken-ichiro Yasuba, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka and Lilik Sutiarso, Development of a field environmental monitoring node with over the air update function, 農業情報研究, 25(3), 86-95, 2016.10.
43. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Zhongxiang Zhu, Parameter sensitivity for tractor lateral stability against Phase I overturn on random road surfaces, Biosystems Engineering, 10.1016/j.biosystemseng.2016.07.004, 150, 10-23, 2016.10, [URL], Statistics show that lateral overturns are the most frequent fatal accidents involving tractors. There is thus much research interest in improving tractor lateral stability. Previous research has discovered the effects of various factors on tractor dynamic responses. While these factors have been analysed separately, their relative significance with respect to other factors remain uncertain. Furthermore, the practical limits of what operators can do have not been considered. The present study assumed a possible case that a tractor operator has several spare tyres of different types and service condition. Additionally, the ballast weight, track width, and implement position can usually be controlled before operation. A scale model tractor was thus developed allowing changes to these factors. The model tractor was designated to pass over typical farming road surfaces. Moreover, the tractor lateral stability was evaluated in terms of the roll angle, lateral-load transfer ratio, and Phase I overturn index. Employing the Taguchi method, we arranged experiments and assessed the applicability of the three kinds of indexes regarding tractor Phase I overturn. Results revealed that the roll angle did not well reflect the initiations of overturns. Compared with the lateral-load transfer ratio, the Phase I overturn index had more convincing factorial effects on tractor stability. Further investigation of the suggested tractor configuration supported this conclusion by comparing predicted and experimental results. In practical cases, this approach may provide a reference for engineers to help operators improve driving safety with limited spare parts..
44. Koichiro Fukami, Toshifumi Mukunoki, Keiko Nakano, Naoki Matsuo, Takashi Okayasu, Water leakage control by using vibratory roller on a dry-seeded rice field in southwestern Japan, Soil and Tillage Research, 166, 138–146, 2016.09.
45. Md Shaha Nur Kabir, Sun Ok Chung, Yong Joo Kim, Geung Joo Lee, Seung Hwa Yu, Kyeong Hwan Lee, Takashi Okayasu, Eiji Inoue, Sensor comparison for grass growth estimation, Journal of the Faculty of Agriculture, Kyushu University, 61, 2, 367-374, 2016.09, Precision agriculture has been implemented in various cultivation operations for various crops. Recently, autonomous mower tractor with variable rate fertilization has been tried. Variable rate fertilization requires quantification of grass growth level. Objective of this study was to compare the performance of potential sensors under different growth levels and sensor operation conditions. A CCD camera, an ultrasonic module, and an optical reflectance sensor (i.e., Crop Circle) were tested at fields with different grass growth levels. Effects of sensor mounting height and angle were investigated. Effects of vehicle (i.e., mower tractor) vibration and traveling were also investigated: under static, vibration and no traveling, and vibration with traveling conditions. Results showed that sensor mounting height had a little effect on the sensor performance, and grass growth level was successfully quantified. Camera angle of 90° showed the best performance with less noise. The ultrasonic sensor could work with less deviation under static condition, whereas, CCD camera proved the applicability under all operating conditions. Operation condition of the optical reflectance sensor showed a little effect on the grass growth detection results. This study would provide information useful for automated grass growth mapping and variable fertilization recommendation..
46. Je Lim, Myoung Ho Kim, Seong Min Kim, Jung Seob Choe, Eiji Inoue, Takashi Okayasu, Dae Cheol Kim, Transport performance simulation of separating system for self-propelled peanut harvester using edem software, Journal of the Faculty of Agriculture, Kyushu University, 61, 2, 361-365, 2016.09, This study evaluated a DEM (Discrete Element Method) model through test results and analysis results for the simulation of the conveying performance of the separating system in a peanut harvester. With the validated DEM model, analysis under three conditions of slope angle of separating system compare with horizon (-7°, 0°, and 7°) was also conducted to examine the conveying performance. From the comparison between the test results and simulation results, the conveying performances of 0° and 7° were observed to be the same at the initial period and completion period; however, the gradient of 0° and 7° from the simulation were higher than the ones from the test by 8.9% (0°) and 9.2% (7°). The higher gradient means that the transport performance is better. The gradient of -7° from the simulation was higher than the one from the test by 3.6%, and the amount of the peanuts from the simulation was larger than the test by 500 g at the initial period of 5 seconds. The higher gradient of the simulation was due to the losses at the collecting part as 3.4% (0°), 3.1% (7°), and 2.0% (-7°). The error in the amount of the peanuts (500 g) at the initial period of 5 seconds with -7° was due to the initial input difference between the test and simulation..
47. Andri Prima Nugroho, Takashi Okayasu, Rin-ichiro Taniguchi, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka and Lilik Sutiarso, Quantification of 2D Lateral Leaf Motion on Mature Plants Foliage using Optical Flow to Study the Circadian Rhythms, Proceesings of the 2nd International Symposium on Agricultural and Biosystem Engineering, 2016.08.
48. Andri, P. N., Okayasu, T., Hoshi, T., Inoue, E., Hirai, Y., Mitsuoka, aM., Lilik, S., Development of a remote environmental monitoring and control framework for tropical horticulture and verification of its validity under unstable network connection in rural area, Computers and Electronics in Agriculture, 10.1016/j.compag.2016.04.025, 124, 325–339, 2016.06.
49. Andri Prima Nugroho, Takashi Okayasu, Takehiko Hoshi, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, and Lilik, Sutiarso:Development of a remote environmental monitoring and control framework for tropical horticulture and verification of its validity under unstable network connection in rural area, Computers and Electronics in Agriculture, 124, 325–339, 2016.06.
50. Hashimoto, Y., Arita, D., Shimada, A., Yoshinaga, T., Okayasu, T., Uchiyama, H., Taniguchi, R., Measurement and Visualization of Farm Work Information, Proc. CIGR-AgEng conference 2016, 2016.06.
51. Iwasaka, S., Hirai, Y., Yamakawa, T., Inoue, E., Okayasu, T., Mitsuoka, M., Accuracy of rice straw weight and rough grain yield predicted by a modified crop growth model based on sucros1, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 592-596, 2016.05.
52. Ogata, M., Hirai, Y., Nakanishi, T., Shikanai, T., Inoue, E., Okayasu, T., Mitsuoka, M., Accuracy evaluation of a method to compute the area of combine-harvested field sections, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 598-602, 2016.05.
53. Okayasu, T., Tanaka, D., Sakai, A., Sakai, Y., Shimada, K., Awai, K., Inoue, E., Hirai, Y., Mitsuoka, M., Plant growth evaluation for leaf vegetables using simple field monitoring system, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 2016.05.
54. Nugroho, A. P., Okayasu, T., Sakai, A., Inoue, E., Hirai, Y., Mitsuoka, M., Sutiarso, L., Automatic leaf motion analysis using optical flow to diagnose plant behavior in response to environmental changes, roceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 2016.05.
55. Sakai, A., Okayasu, T., Yoshinaga, T., Nugroho, A. P., Arita, D., Inoue, E., Hirai, Y., Mitsuoka, M., Effective investigation of 3D feature value extraction for plant body surface using rgb-d sensor, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 2016.05.
56. Hashimoto, Y., Arita, D., Shimda, A., Okayasu, T., Uchiyama, H., Taniguchi, R., Farmer position estimation in a tomato plant green house with smart devices, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 2016.05.
57. Hirai, T., Nakamura, Y., Sakai, A., Okayasu, T., Inoue, E., Mitsuoka, M., Evaluation of a method to estimate light-intercepting characteristics of a rice hill using a RGB-Depth sensor, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 2016.05.
58. Momanyi J. Simanto, M. J., Mitsuoka, M., Inoue, E., Okayasu, T., Hirai, Y., Investigation of the mechanical threshing characteristics of sorghum, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 2016.05.
59. Mitsuoka, M., Takata, K., Inoue, E., Okayasu, T., Hirai, Y., Correlation anomaly detection by using time series data of agricultural machinery, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2016, 2016.05.
60. 安場 健一郎, 多根 知周, 田中 義行, 後藤 丹十郎, 吉田 裕一, 黒崎 秀仁, 岡安 崇史, 星 岳彦, 低コスト環境制御システム構築のためのプログラムライブラリの開発, 農業情報研究, 25(1),12-18, 2016.04.
61. 黒崎 秀仁, 安場 健一郎, 岡安 崇史, 星 岳彦, Arduinoで構成したユビキタス環境制御システム対応ノードのパケット処理能力, 農業情報研究, 25(1), 19-28, 2016.04.
62. Dae–Hyun Lee, Chang–Hyun Choi, Sun–Ok Chung, Yong–Joo Kim, Eiji Inoue and Takashi Okayasu, Evaluation of Tractor Fuel Efficiency using Dynamometer and Baler Operation Cycle, 九州大学大学院農学研究院紀要, 61(1), 173-182, 2016.02.
63. Ju–Seok NAM, Sang–Gon MOON, Sang–Hun PARK, Eiji INOUE, Takashi OKAYASU and Dae–Cheol KIM, Design Parameter Optimization for Tillage Blade of Crank–type Rotavators considering Strength and Weight, 九州大学大学院農学研究院紀要, 61(1), 165-172, 2016.02.
64. Zhen LI, Muneshi MITSUOKA, Eiji INOUE, Takashi OKAYASU, and Yasumaru HIRAI, Effect of Geometric Configuration on Tractor Stability Characteristics, 九州大学大学院農学研究院紀要, 61(1), 153-156, 2016.02.
65. Zhen LI, Muneshi MITSUOKA, Eiji INOUE, Takashi OKAYASU, and Yasumaru HIRAI, Modeling Agricultural Tractor Motion on Sloping Ground Considering Longitu–dinal and Lateral Gradients, 九州大学大学院農学研究院紀要, 61(1), 147-152, 2016.02.
66. Ju Seok Nam, Sang Gon Moon, Sang Hun Park, Eiji Inoue, Takashi Okayasu, Dae Cheol Kim, Design parameter optimization for tillage blade of crank-type rotavators considering strength and weight, Journal of the Faculty of Agriculture, Kyushu University, 61, 1, 165-172, 2016.02, This study conducted design parameter optimization for tillage blade of a crank-type rotavator (45 kW rated power, eight blades). Load, stress, and mass of the blade were obtained from field tests and a commercial program, and design parameter optimization was carried out with them. Selected design parameters were the heights of front and rear ribs, and thickness of the blade. And objective function was minimizing the mass of the blade. Optimization for the nominal tillage blade was conducted considering two different cases of thickness profile: constant thickness of tillage blade in the length direction and inclined thickness. In addition, it was conducted in two different cases of safety factor to consider the changes of tillage load depending on the soil characteristics: higher safety factor on the stress than the nominal tillage blade and lower safety factor. From the results of the optimization for the nominal tillage blade, the mass of the blade reduced by 3.2% under the same safety factor condition. And results of the optimizations with various conditions showed that higher safety factor increased the mass of the blade. The inclined blade also increased the mass of the blade to have the same safety factor. The results of the sensitivity analysis provided that the design parameter affected most on the stress and mass of the blade was thickness of the blade. Therefore, determining appropriate safety factor and thickness of the blade is important in designing the tillage blade. Design parameters of this study do not affect on the surface area of the blade, which is the important influence factor for the tillage performance. Thus, the process used in this study will contribute to the design of tillage blade in minimizing the mass while having similar tillage performance. Further studies on optimization of the shape of the frame and optimization of geometrical structure of the blade will be needed..
67. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Effect of geometrie configuration on tractor stability characteristics, Journal of the Faculty of Agriculture, Kyushu University, 61, 1, 153-156, 2016.02, In this study, tractor stability was discussed from the aspects of rollover initiation, vertical and lateral vibration characteristics considering tractor dynamics in Phase I overturn. As two of the key geometric parameters of a tractor, track width ratio and wheel base ratio were intro-duced into the mathematical model developed earlier as the independent variables. Results showed that both factors greatly reduced the risk of initializing tractor rollover with their in-creasing values. Higher track width ratios were found to generally enhance the contact condition between the sensitive tire and the ground, while higher wheel base ratios showed an effect of stabilizing the vehicle more rapidly after a disturbance. However, no obvious changes in tractor bounce acceleration were observed with the variation in track width ratio, nor were the changes in lateral acceleration found with different values of wheel base ratio..
68. Dae Hyun Lee, Chang Hyun Choi, Sun Ok Chung, Yong Joo Kim, Eiji Inoue, Takashi Okayasu, Evaluation of tractor fuel efficiency using dynamometer and baler operation cycle, Journal of the Faculty of Agriculture, Kyushu University, 61, 1, 173-182, 2016.02, The purpose of this study was to evaluate fuel efficiency of tractor using working cycle. First, baler operation was conducted in Italian ryegrass farmlands and engine torque and fuel consumption were measured as field data. Second, baler operation cycle was developed using the field data. The arbitrary working cycles were generated by randomly selected micro-trips, ininimum working patterns. Some of the arbitrary working cycles were selected and baler operation cycle was determined considering sum of squared difference (SSD). The baler operation cycle was evaluated using performance value (PV) comparing with driving cycles. The results showed that PVs of the driving cycles were 67 - 109% of the baler operation cycle. Third, fuel efficiency of the baler operation was evaluated by dynamometer test using dynamometer system and the baler operation cycle. The fuel consumption and engine power were measured while the engine acted on the baler operation cycle and fuel efficiency was evaluated. The results of t-test showed no significant difference between fuel efficiency by the dynamometer test and fuel efficiency of each farmland by the field test. Considering all results of this study, the baler operation cycle is feasible to apply to evaluate fuel efficiency of tractor with dynamometer system..
69. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Modeling agricultural tractor motion on sloping ground considering longitu-dinal and lateral gradients, Journal of the Faculty of Agriculture, Kyushu University, 61, 1, 147-152, 2016.02, Tractor overturning or rollover is a serious accident owing to its high fatality rate. Reviews of farm tractor rollover incidents indicate that overturns account for over 50% of all tractor-related deaths. To understand a tractor's performance on uneven terrain, a three-dimensional (3D) mathematical model describing the general bouncing and pitching motions of a tractor would be very useful. In this study, we design a rigid-body tractor system with the tires modeled as spring-damper units. To predict the tractor's motion on undulating surfaces, a half sine wave bump is adopted for the front and rear wheels on both the longitudinal and transverse slopes. The tractor's dimensional parameters and physical properties are taken from the work of Takeda et al. (2010). The passing over process is divided into four detailed phases and the attitude of the tractor is obtained by capturing the motion of the vehicle's center of gravity (COG). The displacement, pitch angle, and accelerations of the COG are numerically analyzed by applying the Runge-Kutta method. We introduce in this study three coordinates for the vehicle, slope and horizontal ground-based observations. The results are presented as factors of forward velocity, bump height, and slope gradient. Predictions show that there is a decrease in stability and an increase in danger at higher velocities, higher bump heights, and steep inclines. The specific cases indicating dangerous situations for the tractor are pointed out according to the results..
70. Mansur Ahmed, Akinori Ozaki, Kazuo Ogata, Shoichi Ito, Ikuo Miyajima, Ashir Uddin Ahmed, Takashi Okayasu, Dipok K. Choudhury, Nayeen Al Amin, Poor farmer, entrepreneurs and ICT relation in production & marketing of quality vegetables in Bangladesh, Journal of the Faculty of Agriculture, Kyushu University, 61, 1, 241-250, 2016.02, Bangladesh is a country where people mostly depend on agriculture. The crop sub-sector of agriculture mainly depends on extensive agrochemicals to increase production and to ensure the national food security. Although, farmers have been using agrochemicals, the production was still found not to increase significantly due to the lack of knowledge about proper and modern cultivation technology. In addition, farmers are getting less income from agriculture compared to another profession, because of the inconsistent price of agricultural produces between the rural and urban area. In order to improve the situation, Kyushu University has conducted JICA (Japan International Cooperation Agency) grassroots technical cooperation project which aims at income generation for BOP (Bottom of Pyramid) farmers by producing and marketing the chemical free quality vegetables using ICT (Information and Communication Technology). The project has been conducted in five rural areas in Bangladesh. Here, the farmers are producing vegetables under a quality vegetable management center (QVMC) which is well equipped with ICT tools, and a quality vegetable entrepreneur (QVE) is helping them regularly to get the desired production and also ensuring the marketing of such vegetables. The project has targeted 100 farmers for producing chemical free vegetables and already got 42 interested farmers in 1.5 years of time. It is observed that farmers get better production under this QVMC in the winter season (called "Rabi" in Bangladesh) than summer season (called "Kharif-1" in Bangladesh)..
71. 境 淳成,岡安崇史,吉永 崇,有田大作,三好悠太,北野雅治, 井上英二,平井康丸,光岡宗司, RGB-Dセンサを用いた植物体情報の計測とその精度評価, 農業食料工学会九州支部誌, 64, 15-20, 2015.08.
72. Li, Z., Mitsuoka, M., Inoue, E., Okayasu, T., Hirai, Y., Development of stability indicators for dynamic Phase I overturn of conventional farm tractors with front axle pivot, Biosystems Engineering, 134, 55-67, 2015.06.
73. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Development of stability indicators for dynamic Phase I overturn of conventional farm tractors with front axle pivot, Biosystems Engineering, 10.1016/j.biosystemseng.2015.03.016, 134, 55-67, 2015.06, [URL], Tractor overturns are serious potential hazards for operators. While rollover protective structures (ROPS) protect operators passively, greater protection can be achieved through theoretical prediction of a potential overturn. Given effective warning, an operator can act to correct a tractor's motion when a tyre is about to lose contact with the ground. Such a loss of contact is associated with the initiation of a Phase I tractor overturn. However, it remains unclear how the initiation of tractor overturn is influenced by certain factors. Furthermore, the current mathematical models for tractors should be further extended for general utilisation. This study was conducted to develop stability indicators based on a more general model for dynamic Phase I tractor overturn. We considered practical tractor configurations and motion characteristics in a three-dimensional (3D) reference frame in formulating the mathematical model. Tractor stability indicators for overturn and sideslip were derived from force calculations. A parametric study was conducted using an example tractor. The tractor speed and slope angle were found to affect the overturning stability significantly. The coefficient of maximum static friction was found to be the main factor contributing to tractor sideslip. Critical tractor speeds for various ground conditions were identified by considering the zero values of the tractor stability indicators. The critical tractor speed was determined as a function of the maximum static friction and the slope angle. By providing a display device based on ergonomics principles, the results of this study can be further implemented in the form of guidance to operators..
74. Bong-Jin KIM, Young-Sun Kang, Hong-Gon KIM , Eiji INOUE ,Takashi OKAYASU, Dae-Cheol KIM, Analysis of the Separating Performance of Peanut Harvester Sorting System, Journal of the Faculty of Agriculture Kyushu University, 2015.02.
75. 田中大介,岡安崇史,永尾宏臣,坂井佑輔,粟井一勝,井上英二,平井康丸,光岡宗司 , 農作業履歴収集の電子化とその利活用技術の開発, 九州大学大学院農学研究院学芸雑誌 , 70(1), 15-20, 2015.02.
76. Bong Jin Kim, Young Sun Kang, Hong Gon Kim, Eiji Inoue, Takashi Okayasu, Dae Cheol Kim, Analysis of the separating performance of peanut harvester sorting system, Journal of the Faculty of Agriculture, Kyushu University, 60, 1, 209-214, 2015.01, This study examined the performance of the separating system of a self-propelled peanut harvester by analyzing the relationship between a shaking screen and rotational speeds of winnowing. The shaking screen was manufactured to have rotational speeds of 370, 470, 570 rpm and winnowing was manufactured to have rotational speeds of 1,500, 1,760, 2,020 rpm by adjusting the pitch circle diameter of each pulley. The sample was prepared based on the yields of an actual self-propelled peanut harvester and analyzed with Statistical Analysis Software after measuring the weight of peanuts and stems. The stem separation ratio was high as 95.3% when rotational speeds were 570 rpm (shaking screen) and 2,020 rpm (winnowing). The peanut loss ratio was low as 0% when rotational speeds were 370 rpm (shaking screen) and 1,500 rpm (winnowing). The results indicated that the stem separation ratio was improved with high rotational speeds of shaking screen and winnowing; the peanut loss ratio was reduced with low rotational speeds of shaking screen and winnowing. However, the rotational speed of winnowing did not influence on the peanut loss ratio; as a result, separation performance was improved with low rotational speed of shaking screen and high rotational speed of winnowing. Low rotational speed of shaking screen, however, may cause congestion during process, thus follow-up studies are needed..
77. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Zhongxiang Zhu, Modification of a tractor dynamic model considering the rotatable front end, Journal of the Faculty of Agriculture, Kyushu University, 60, 1, 219-224, 2015.01, A mathematical model for tractor dynamics was expanded by considering the rotatable tractor front end. The fundamental shortcoming of the simplified model was revealed by the loss of contact of the tire with a rigid horizontal surface in an obstacle-passing case. Further shortcomings of the simplified model arise from aspects of the motion and vibration characteristics. The improved model provides a better and more realistic representation of the tire-ground contact condition and is applicable to tractors on lateral slopes. The independent roll motions of the two main tractor parts (the front end and main body) significantly reduce the motions of the tractor and thus increase its stability. Furthermore, the effects of the forward tractor speed and obstacle height were studied for a tractor on a 10° lateral slope. By analyzing the motion amplitude and tire-ground contact condition, the tractor speed and obstacle height parameters associated with danger and risk were evaluated. The results suggest the greater capability of the improved model to predict tractor dynamic response in Phase I overturn..
78. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Zhongxiang Zhu, Prediction of tractor sideslipping behavior using a quasi-static model, Journal of the Faculty of Agriculture, Kyushu University, 60, 1, 215-218, 2015.01, Tractor stability predominantly determines operator's safety. For a tractor parking on lateral slopes, overturning accidents have been frequently discussed using mathematical models. While the existing static models remarkably contribute tractor overturning mechanisms, few of them have considered the stability from the perspective of tractor sideslip. In our study, a relatively precise quasi-static model presented recently was adopted as the base model. We expanded it by introducing potential tractor sideslips. While the original model pointed out the lateral slope angle as the main factor influencing tractor overturns, we investigated tractor slipping stability under the influences of the slope angle and the coefficient of friction. The dimensional parameters of the example tractor for simulation were set the same as those in the original work. It was found that the allowable friction forces of both the front and rear tires primarily depended on the coefficient of friction rather than the slope angle. By comparing the surfaces of the allowable friction forces and the corresponding friction forces, tractor slipping thresholds for the front and rear tires were identified. Caution areas implying certain ground conditions that will definitely cause tractor sideslip were marked accordingly. The results shown in this study provide a relatively comprehensive way to understand tractor static stability when both tractor sideslip and overturn are concerned..
79. Borin Khem, Hirai Yasumaru, Takeo Yamakawa, Yuki Mori, Eiji Inoue, Takashi Okayasu, Mitsuoka Muneshi, Production of rice for whole crop silage using manure in Itoshima Region, Fukuoka prefecture, Journal of the Faculty of Agriculture, Kyushu University, 60, 1, 65-71, 2015.01, The cultivation area of rice for whole crop silage (WCS) has rapidly increased in the last decade in Japan due to increasing demand for domestic livestock feed as well as a measure for the use of redundant paddy field. On the other hand, the production cost of rice for WCS is largely supported by subsidy now, so it is required to reduce the production cost. Manure application is a prospective way to reduce the cost of fertilizer and to sustain soil fertility. Thus, we investigated the production of rice for WCS using manure in Itoshima region, Fukuoka Prefecture, Japan, from the aspects of soil fertility, plant growth, and dry matter weight. The fields where manure was applied showed relatively high TN contents in soil whereas fields where manure was not applied showed low TN contents. This result indicated that soil fertility can be deteriorated by the continuous production of rice for WCS when organic matter is not supplied by manure and other materials. Plant length (r=0.748) and tiller number (r=0.891∗∗) at panicle initiation stage were closely correlated with TN content in soil whereas SPAD readings (r=0.846∗∗) at the same stage was closely correlated with mineralized N in soil. Dry matter weight was positively correlated with TN content in soil (r=0.767∗∗). Fields where manure was not applied had small dry matter weight although nitrogen was supplied from fertilizer. These results indicated that dry matter weight was significantly affected by soil fertility..
80. Takashi Okayasu, Takahisa Nakamura, Katsumi Muramoto, Yoshitsugu Momoya, Elastoplastic deformation behavior for ballast under monotonic and cyclic loading conditions, Proceedings of International Conference on International Society for Terrain-Vehicle Systems, 2014.09.
81. Jung Seob Choe, Eiji Inoue, Muneshi Mitusoka, Takashi Okayasu, Hirai Yasumaru, Performance of measuring vibration of MEMS sensor, Journal of the Faculty of Agriculture, Kyushu University, 59, 2, 351-358, 2014.08, The purpose of this study is to examine the usefulness of an MEMS sensor for measuring vibration of agricultural vehicle by obtaining serial data of vibration acceleration of agricultural vehicle using an MEMS sensor and translational accelerometer and thereby calculating RMS and PSD for comparison and analysis as a step before construction of measuring system which can identify operating conditions of agricultural packaging machinery at all times. Although there are differences between vertical acceleration RMS and pitching angular acceleration measured by an MEMS sensor and translational accelerometer due to disturbance factors and computation errors, both measurements obtained by the two methods typically increase as vehicle body moves faster. For PSD, likewise RMS, there were differences in measurements, but peak frequencies were almost matched between the two methods, so it was confirmed that an MEMS sensor could exactly detect vibration characteristics. Therefore, it was considered that instead of large and costly translational accelerometer, an MEMS sensor which can measure both translational acceleration (back-and-forth, lateral, and vertical) and angular acceleration (rolling, pitching, and yawing) only with a single unit could be properly used in identifying vibration characteristics of agricultural packaging machinery..
82. Andri Prima Nugroho, Takashi Okayasu, Sribudi Astuti, Muneshi Mitsuoka, Eiji Inoue, Yasumaru Hirai, Lilik Sutiarso, Deployment of agricultural information system – installation and utilization of field monitoring system on agricultural production in Yogyakarta, Indonesia, Proceesings of The International Conference on Sustainable Innovation (ICOSI) 2013, 10.13140/2.1.1643.8401, 2014.06.
83. Muneshi Mitsuoka, Yuki Kimoto, Kohei Takata, Eiji Inoue, Takashi Okayasu, Yasumaru Hirai, Abnormal detection of agricultural machineries using multi-time series, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2014, 2014.05.
84. Satoru Umeno, Eiji Inoue, Muneshi Mitsuoka, Takashi Okayasu, Yasumaru Hirai, Study on noise reduction in cabin of agricultural machineries using active noise control method, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2014, 2014.05.
85. Takashi Okayasu, Toshihisa Fukuda, Keita Tsuchiya, Koichiro Fukami, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, Development of soil tillage simulator using fem-dem quasi-coupling method, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2014, 2014.05.
86. Takashi Okayasu, Daisaku Arita, Andri Prima Nugroho, Takehiko Hoshi, Takashi Yoshinaga, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, Effectiveness evaluation on utilization of two snss in japan agriculture, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2014, 2014.05.
87. Yasumaru Hirai, Kodai Tanaka, Tsuneo Nakanishi, Takeshi Shikanai, Eiji Inoue, Akira Fukuda, Takashi Okayasu, Muneshi Mitsuoka, Evaluation of measurement accuracy of the harvest area corresponding to each shipment to country elevator using GPS and QZSS, Proceedings of International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2014, 2014.05.
88. 尾﨑彰則・緒方一夫・アシル アハメッド・宮島郁夫・岡安崇史・大杉卓三・田中祥子, バングラデシュにおけるICTを用いた農業情報支援による貧困層農家の所得向上, 農学国際協力, 13, 2014.04.
89. 丸居篤・藤堂乃夫宏・岡安崇史・後藤貴文・衛藤哲次・塩塚雄二・高橋秀之, 放牧による耕作放棄地解消がイノシシの行動に及ぼす影響, 日本暖地畜産学会報, 2014.04.
90. 平井康丸・西本琢人・猿田恵輔・田中恒大・井上 英二・岡安 崇史・光岡 宗司, 植物面積指数および葉緑素計値に基づく複数の水稲生育指標の推定法,, システム農学, 30, 2, 49-60, 2014.04.
91. 田中恒大・平井康丸・猿田恵輔・井上 英二・岡安 崇史・光岡 宗司, 水稲の収量・品質決定要因解析手法としての回帰木の適用, 日作紀, 83, 2, 143-154, 2014.04.
92. Yuko Ueka, Masami Matsui, Eiji Inoue, Muneshi Mitsuoka, Takashi Okayasu, Shape model of grain and straw using coupling elements and flight simulation of threshing unit of combine by discrete element method, Engineering in Agriculture Environment and Food, 2014.02.
93. 田中恒大・平井康丸・鹿内健志・井上 英二・岡安 崇史・光岡 宗司, GPS記録計を用いた精玄米収量計測法, 九大農学芸誌, 69, 1, 1-7, 2014.02.
94. Kodai Tanaka, Hirai Yasumaru, Keisuke Saruta, Eiji Inoue, Takashi Okayasu, Mitsuoka Muneshi, Application of a regression tree to analysis of rice yield and quality determinants, Japanese Journal of Crop Science, 10.1626/jcs.83.143, 83, 2, 143-154, 2014.01, [URL], In recent years, it is becoming important to collect and utilize different data on rice production to achieve a high yield and high quality, and to transfer the skill to the next generation. The objective of this study was to investigate the validity of a regression tree for analysis of yield and quality determinants. Determinants of grain yield (yield), 1000-grain weight, and protein content of brown rice (protein) were analyzed by focusing on explanatory variables for the meteorological environment and conditions of rice growth and nutrition after the heading period. The spikelet number/m2 was identified as a yield determinant by a regression tree and multiple regression analysis. However, the predictive accuracy was higher in multiple regression analysis due to a strong linear correlation between yield and spikelet number/m2. For the analysis of the 1000-grain weight with nonlinear data structure, no reasonable determinant was identified in multiple regression analysis, while a regression tree implied the 1000-grain weight determinant by clarifying its relationship with SPAD readings about 20-d after heading (SPAD20). The SPAD20 was also identified as a protein determinant. Furthermore, it was indicated for data under the condition with high SPAD readings that protein was lowered by the high temperature during 5 to 30 days period after heading. A regression tree can clarify the relationship among parts of data by splitting data hierarchically, but multiple regression analysis can not..
95. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Dynamic analysis of agricultural wheel tractor driving on uneven surface under the influences of speed and slope angle, Journal of the Faculty of Agriculture, Kyushu University, 59, 2, 339-343, 2014.01, A dynamic three-dimensional model of a tractor travelling through a half sine wave obstacle was developed considering bouncing, pitching, and rolling motions. Compared with the case of bouncing on a level road, setting the obstacle on a sideways slope under the upper side of the forwarding tractor could stimulates a much more dangerous scenario, which may lead to tractor overturn. In this model, the tractor was considered as a rigid body, except for the tires, which were regarded as spring-damper units. The entire passing-over process was divided into four periods as done by Yamamoto and Shimada (1957), and Takeda et al. (2010) for dissecting the influence of each specific travelling period on the tractor. Basic dimensional parameters and physical properties of the objective tractor, used as input parameters in our simulation, were cited directly from the work of Takeda et al. (2010). Dynamic behavior of the tractor was described by capturing the motion of its center of gravity, which includes vertical displacement, angle, and angular acceleration for the pitching and rolling phenomena. Using the Runge-Kutta method, the desired mathematical model was numerically simulated through programming in Visual Basic Application language within Microsoft Excel. Tractor dynamic predictions were presented as factors of forward constant speed and lateral slope. The simulation results show fluctuations and increase in danger levels owing to higher velocities and steep lateral slopes. Therefore, this model enables us to explore potential overturning judgment standards..
96. Takashi Okayasu, Takahisa Nakamura, Katsumi Muramoto, Yoshitsugu Momoya, Elastoplastic deformation behavior for ballast under monotonic and cyclic loading conditions, 18th International Conference of the International Society for Terrain-Vehicle Systems, ISTVS 2014
18th International Conference of the ISTVS
, 2014.01, Various constitutive models for soils and gravels have been developed in the last century. Among them unconventional plasticity theory is a key and necessary approach for describing cyclic deformation behavior of materials. The "subloading surface model" proposed by Hashiguchi, which belongs to the unconventional plasticity framework, does not assume a purely-elastic domain inside a yield surface and premises that an inelastic strain is induced by stress changes inside the yield surface. It is able to describe the mechanical behavior of materials such as not only smooth elastoplastic transition but also cyclic loading behavior. Thus, elastoplastic constitutive models for various materials based on this model have been developed up to present. Moreover computational analysis methods such as a finite element method (FEM) incorporating this constitutive model have been utilized for solving problems in geotechnical engineering fields. On the other hand, gravel such as ballast causes elastoplastic deformation in the proportional loading process. However the accumulation of the plastic deformation under a cyclic loading condition is smaller than that for typical soils such as sand and clay in general since the elastic property of ballast particle is high and the slip between each ballast is remarkably suppressed by the particles' packing. In this study, the subloading surface model is modified by assuming an existence of the elastic domain surface inside the subloading surface so as to realistically describe the inelastic deformation behavior of ballast including monotonic and cyclic loading conditions. The validity of the model is verified by the comparison with large-scale triaxial compression test data for both loading conditions..
97. Zhen Li, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, Lateral slope effect on tipping behavior of a tractor encountering an obstacle (model development), Journal of the Faculty of Agriculture, Kyushu University, 59, 2, 345-349, 2014.01, A three-dimensional mathematical model of tractor on lateral slopes was developed in this study. The model considers the nonlinear geometric relationships of the arms of the ground supporting forces when the tractor passes over a half sine curve obstacle. It is subsequently ap-phcable to large rotations of a tractor. Meanwhile, the change of the direction of a supporting force due to the interaction between tractor pitch and roll motions and its result in corresponding tire deformation are the concern of this study. Given the transformation matrix, the tractor translations and rotational motions were observed in a global coordinate. According to the de-veloped model, one can obtain the tractor bounce displacement, the pitch angle, and the accel-eration characteristics. Furthermore, the supporting and lateral friction forces can be examined since they predominantly determine the tractor lateral rollover and sideslip which affect tractor safety to a great extent. Therefore, the lateral slope effect on these forces was investigated con-sidering a tractor speed of 0.5 m/s and an obstacle height of 0.08 m. Results showed that as the slope angle increases, both the supporting and lateral friction forces put the tractor to a situation closer to danger. In particular, a specific slope angle of 25' was highlighted as a warning parameter because the onset of rollover as well as tractor sideslip were discovered. It is also found that a tractor is more susceptible to sideslip than rollover along with the slope increasing..
98. Yuko Ueka, Masami Matsui, Eiji Inoue, Mitsuoka Muneshi, Takashi Okayasu, Shape model of grain and straw using coupling elements and flight simulation of threshing unit of combine by discrete element method, Engineering in Agriculture, Environment and Food, 10.1016/j.eaef.2013.12.006, 7, 1, 34-39, 2014.01, [URL], The threshing unit of a combine comprises a multiphase flow; therefore, it is essential to consider it on the basis of the flow model. In this study, flight simulation by DEM with fixed wind velocity was carried out. The grain and straw were considered to be ellipsoidal and cuboidal, respectively. A two-dimensional model coupling with a circle element was constructed. Each flight trajectory was reproduced in terms of the initial conditions and changes in winnowing velocity. The average flight velocity of the grain was 0.2 m/s higher than that measured in the experiment. It can simulate to closer phenomenon by mixing different particle mass and straw, analyzing the increase in particles and linking it with fluid analysis..
99. Hirai Yasumaru, Takeo Yamakawa, Yuki Mori, Teruaki Nanseki, Eiji Inoue, Takashi Okayasu, Mitsuoka Muneshi, 7-1-6 パターン認識を用いた水稲の収量・タンパク質含有率予測モデル(7-1 肥料および施肥法,2014年度東京大会), 日本土壌肥料学会講演要旨集, 10.20710/dohikouen.60.0_117_3, 60, 0, 117, 2014, [URL].
100. Keisuke Saruta, Yasumaru Hirai, Kodai Tanaka, Eiji Inoue, Takashi OKAYASU, Muneshi Mitsuoka, Predictive models for yield and protein content of brown rice using support vector machine, Computers and Electronics in Agriculture, http://dx.doi.org/10.1016/j.compag.2013.09.003, 99, 93-100, 2013.11, Rice production in Japan is facing problems of yield and quality instability owing to recent climate changes, aging of farmers, and a decrease in the farmer population. Thus, it is becoming important to develop an improved rice production technology that utilizes collected data about rice production rather than relying on the conventional technology that is based on the experience and knowledge of individual farmers. We developed predictive models for yield and protein content of brown rice that can provide useful knowledge to support farmer’s management decision-making, utilizing data sets from 47 paddy fields where rice was produced under various environments and management styles. Support vector machines (SVMs) were applied to build the predictive models based on explanatory variables representing the growth and nutrition conditions after the heading stage and the meteorological environment after the late spikelet initiation stage. The models achieved quantitative accuracy that was within approximately 1 t ha−1 in yield for 85.1% of the total data sets and within 0.8% in protein content for 76.6% of the total data sets, respectively. Further, patterns of explanatory variables classified in three classes of yield and protein content, which were visualized by the predictive models, were reasonable in terms of knowledge of crop science. We found that the predictive models using SVMs had the potential to describe a relation between yield or protein content and multiple explanatory variables that reflected diverse rice production in actual fields, and could provide useful knowledge for decision-making of topdressing and basal fertilization.

Keywords
Rice production; Yield; Protein content; Predictive model; Support vector machine; Pattern recognition.
101. 岡安 崇史, Andri Prima Nugroho, 尾﨑 彰則, 光岡 宗司, 南石 晃明, 井上 英二, 平井 康丸, 変化点分析法を用いた圃場環境情報の特徴量抽出とその妥当性の検証, 農業情報研究, 22, 3, 174-182, 2013.10, 圃場に設置された簡易モニタリング装置を用いて計測・収集される環境データは,作物の生育状況,病害虫の発生等の把握・予測のみならず,播種・移植,潅水,施肥,防除,収穫等の種々の農作業の最適化のための重要な情報となる.しかしながら,モニタリング装置の設置台数,さらには各装置に接続されたセンサー数の増加に伴い,データベースに保管されるた計測データは急速に増大していくすることが予想される.このため,これら膨大なデータの中から農業生産に必要なデータを効率的かつ迅速に抽出するための技術の開発が求められるている.本稿では,まず,圃場環境の常時監視,農業生産工程の最適化,農家間での生産情報の共有等を目的に著者らが開発を行ったハウス内環境の簡易モニタリングシステムについて概説する.次に,特異スペクトル変換と称される時系列データ解析手法に基づく特徴量抽出プログラムを開発し,同モニタリングシステムで計測されたハウス内環境情報の変化点の抽出,さらには,抽出した変化点情報と農作業履歴データとの比較・照査を行い,本解析手法ならびに自動検出された変化点情報の妥当性について検討を行った..
102. 川村富輝,中野恵子,光岡宗司,井上英二,岡安崇史, 部分浅耕播種法がコムギの品質・収量および播種の省力化に及ぼす影響, 農作業研究, 48, 3, 111-120, 2013.09.
103. Takashi OKAYASU, Andri Prima Nugroho, Daisaku Arita, Akinori Ozaki, Mitsuoka Muneshi, Teruaki NANSEKI, Eiji Inoue, Hirai Yasumaru, Environmental Change Point Analysis and Its Application to Agriculture, Proceedings of International conference on Instrumentation, Control, Information Technology and System Integration, 2013.09, Field environmental information such as air temperature, humidity, and solar radiation would be important not only for evaluation of crop growth progress, status and quality or the occurrence of pests and diseases, but also for optimization of agricultural production processes such as plating, irrigation, fertilization, pest control, and harvesting. However, measured data stored in an agricultural information database, would be vast data with the increase in the number of monitoring devices and sensors installed in such devices. Thus, in order to extract feature values from such vast data, it is necessary to develop some numerical technologies and methods. In this study, the change point analysis based on Singular Spectrum Transformation (SST) was applied for extracting the difference of cultivation environmental conditions in each the tomato greenhouse. The change point scores were detected from the change of CO2 concentration data clearly. They agreed well with the farm work history recorded by a corporative farmer..
104. Dae Chun Kim, Ju Seok Nam, Myoung Ho Kim, Jung Seob Choe, Eiji Inoue, Takashi Okayasu, Dae Cheol Kim, Analysis of the tillage and power consumption characteristics of a crank-type rotavator according to the tillage blade shape, Journal of the Faculty of Agriculture, Kyushu University, 58, 2, 319-328, 2013.09, In this study, the effects of tillage blade shape on tillage and power consumption characteristics were investigated for a crank-type rotavator. Three types of tillage blades were applied, i.e. standard blade, endsloped blade and narrow blade for the purpose of the study. Tillage operations were carried out using each blade with the same prime mover tractor and rotavator platforms in two different soil and Power Take-Off (PTO) speed conditions. During the operations, PTO speed and torque, soil pulverizing ratio and inversion ratio, actual work speed, and rotavating width and depth were measured, and the required power of the PTO shaft, field capacity and flow of tilled soil were calculated to compare the characteristics according to the tillage blade shape. Experimental results show that the rotavating width, actual work speed, field capacity, flow of tilled soil and soil inversion ratio were independent of the blade shape, whereas the rotavating depth and soil pulverizing ratio were influenced by the blade shape according to the soil condition. In the most commonly used tractor gear conditions of L2 and L3, the PTO power of the end-sloped blade and narrow blade were almost the same as each other, and significantly lower than the standard blade in the paddy field, whereas there were no significant differences among blades in the dry field. It can be concluded that if an adequate blade shape suitable for specific soil conditions is applied to the crank-type rotavator, power efficiency and good tillage performance operation can be achieved at the same time. Further research is needed to determine the optimal shape of tillage blade with certain soil properties..
105. Hyuck Joo Kim, Myoung Ho Kim, Eiji Inoue, Takashi Okayasu, Dae Cheol Kim, Ergonomic study for comfort operating the pedals of the agricultural tractors, Journal of the Faculty of Agriculture, Kyushu University, 58, 2, 329-338, 2013.09, Aging and feminization of farming population are a major burden on current agricultural sector, and some measures are demanding to adjust this trend. The agricultural mechanization has relieved farmers of most of the hard physical labor, but still work environments are poor, and there are a lot of harmful factors affecting human health. Therefore, improvement of safety and comfort in agricultural machinery is needed. In case of the most commonly used domestic agricultural machinery, agricultural tractors, operation device location and operating force are regulated by international rules such as ISO 4253, but the rule is not sufficient for domestic operators, since it was not developed for operator's comfort and was drawn out based on the westerners. In this study, we developed a technique that evaluates the conformability of tractor driving operation device for all Korean farmers including senior and women farmers. We also established evaluation equipments and inspection method of tractor operation conformability to promote dissemination of tractors that suit for Korean farmers' physique. In the future, the result allows tractor manufacturers to propose design guidelines for proper location and operating force of tractor operating device. It also allows domestic agriculture manufacturers to develop agricultural machinery that considered the conformability of farmers from the design stage..
106. Andri Prima NUGROHO, Takashi OKAYASU, Mitsuoka Muneshi, Eiji Inoue, Lilik SUTIARSO, Hirai Yasumaru, Development of Web-based Change Point Analysis for Field Environmental Information in Agriculture, Proceedings of International Symposium on Agricultural and Biosystem Engineering 2013, 2013.08.
107. Takahisa FUKUDA, Takashi OKAYASU, Keita TSUCHIYA, Eiji Inoue, Hirai Yasumaru, Mitsuoka Muneshi, Modeling and Prediction of the Mechanical Interaction between Soil and Tillage Tool by DEM, Proc. 11th Int. Conf. Anal. Discontinuous Deformation, 2013.08, Tillage is one of important operations to improve and maintain top soil condition in farmland. The soil condition is different according to soil types and region in general. Various kinds of the tillage methods and tools have been developed up to present. However, their developments have been often conducted by experience and sense using trial and error methods. From these backgrounds, developments of numerical analysis method have been tried to clarify the mechanism for soil-tillage interaction phenomena and to reduce the developing time and costs. In this study, the soil-tillage interaction simulation was established by a three-dimensional geometry of a disk plow and soil layer modeled by using discrete element method (DEM). Trac-tion resistances acting on the disk plow and soil cutting phenomena were estimated in the simulation. They were compared with the experimental results. The simulated results agreed qualitatively with the experimental results..
108. Yuta Miyoshi, Kota Hidaka, Takashi Okayasu, Osamu Hirano, Daisuke Yasutake, Kitano Masaharu, Application of the constant soil temperature layer for energy-saving control of the local environment of greenhouse crops. I. Local control of the ambient environment of strawberry, Environmental Control in Biology, 10.2525/ecb.51.89, 51, 2, 89-94, 2013.08, [URL], In a farmer's strawberry greenhouse, seasonal changes in solar radiation and air conditions (temperature, humidity, and CO2 concentration) were measured, and it became clear that the stable year-round production of strawberry was depressed by low temperature and low solar radiation in the cold season and by excessively high temperature in early autumn. Furthermore, dew formations during the nighttime and inappropriate application of CO2 enrichment were also related to the depression of stable production. Therefore, a local environmental control system was newly developed for strawberry crops based on air circulation and heat exchange between the constant soil temperature layer and the ambient air. The system consisted of an underground air pipe (UAP) and perforated inter-row air ducts (IAD) connected to the UAP; the UAP was set at a depth of 1.5 m, where soil temperature remained suitable for year-round strawberry growth. The greenhouse air was drawn into the UAP, and the air flowing through the UAP exchanged heat with the constant soil temperature layer and was dispersed to the ambient environment of the strawberry crops through the perforated IAD. In the nighttime during the cold season, air flowing through the system was heated by 8°C, and a heating effect of 3°C was observed in the ambient air. The proposed system of applying the constant soil temperature layer can be expected to reduce the nighttime heating load by 50% and enable energy-saving environmental control..
109. 川村富輝,小田原孝治,光岡宗司,井上英二,岡安崇史, 転換畑における部分浅耕播種法がダイズの生育・収量に及ぼす影響, 農作業研究, 48, 2, 49-59, 2013.06, [URL].
110. Yuta MIYOSHI, Kota HIDAKA, Takashi OKAYASU, Osamu HIRANO, Daisuke YASUTAKE, KITANO Masaharu, Application of the Constant Soil Temperature Layer for Energy-saving Control of the Local Environment of Greenhouse Crops. I. Local Control of the Ambient Environment of Strawberry, Environ. Control Biol., 51, 2, 89-94, 2013.05.
111. Miyoshi, Y., Hidaka, K., Okayasu, T., Hirano, O., Yasutake, D., Kitano, M., Approach to Local Enviroment Control for Stable Production of Stawberry, Proc. IFAC2013 Bio Robotics Conf., Web(4 pages), 2013.03.
112. Andri, N.P., Okayasu, T., Inoue, E., Hirai, Y. and Mitsuoka, M., Development of Actuation Framework for Agricultural Informatization Supporting System, Proc. IFAC2013 Bio Robotics Conf., C-16(6 pages), 2013.03.
113. Saengprachatanarug, K., Ueno, M., Taira, E., Takashi OKAYASU, Modeling of soil displacement and soil strain distribution under a traveling wheel, Journal of Terramechanics, http://dx.doi.org/10.1016/j.jterra.2012.06.001, 50, 1, 5-16, 2013.02, The empirical Gaussian-based mathematical model of the soil displacement increment under a traveling wheel was extended to be applicable to any depth of soil layer under the ground contact surface of the wheel. The unknown coefficients were obtained by least mean-square fitting with the soil displacement curve measured through a sophisticated laboratory soil bin test. Those coefficients were then re-derived as a function of depth. The movement of soil particles at the ground contact surface was modeled by dividing movement into two kinds; first, the free movement of soil particles before contact with the wheel and the movement of the particles after they are separated from the wheel surface and, second, soil movement during attachment to the wheel surface. By combining the models for the ground contact surface of the wheel with that for all soil layers, an extended model that can describe soil displacement increment in both vertical and horizontal directions using one equation was established. The predicted results obtained using the extended model fitted quite well with the measured values. The predicted strain increment distributions also show the same trends as the measured distributions..
114. Jong Min Park, Ghi Seok Kim, Soon Hong Kwon, Sung Won Chung, Soon Goo Kwon, Won Sik Choi, Jong Soon Kim, Muneshi Mitusoka, Eiji Inoue, Takashi Okayasu, Development of Post-harvest bulk handling system of onions (I) - Characteristics of friction and airflow resistance, Journal of the Faculty of Agriculture, Kyushu University, 58, 1, 87-92, 2013.02, Onion is one of the major vegetables and is also the number one crop from the perspective of storage amount in South Korea. However, the postharvest processing for onions has been accomplished mainly with net package, causing high cost and low efficiency. Thus, development of a continuous and integrated processing system is required to ensure buyer satisfaction and marketing success. The objective was to determine factional properties and airflow resistance of onion, which are very important to understand the behavior of onions in developing its bulk handling system. Frictional properties of onions, friction coefficient and rolling resistance, were determined by the method of inclined surface. Those values were investigated on three different surfaces (rubber, plywood, and galvanized steel) for four size grades (extra-large, large, medium, small). The airflow resistance, or static pressure drop, was measured with different mixing rate of onion sizes, and equations were developed for prediction of pressure drop in bulk state. The static-friction coefficient ranged from 0.35 to 0.46 for all experiment condition. The highest value was obtained on the plywood surface (0.46+0.06) followed by the rubber (0.41±0.03) and galvanized steel surface (0.35±0.03). This friction coefficient decreased with the onion bulb size. The static-rolling resistance ranged from 8.4' to 17.6° for all sizes, and, unlike the friction coefficient, increased with the onion bulb size. The highest values of rolling angles were obtained on the rubber surface (15.43±4.78) followed by the plywood (13.77±3.77) and galvanized steel surface (10.84±4.26). The airflow resistance increased as the onion size decreased, and a low porosity produced a higher pressure drop in all mixing rate of onion size. The pressure drop in stacked onion was also proportional to the superficial air velocity. Equation developed for prediction of pressure drop with superficial air velocity (SV) and stacking depth (SD) (r2=0.99) was better than one with stacking depth (SD) (r2=0.95) only. These results are invaluable to design post-harvest bulk handling system of onions..
115. Jung Seob Choe, Muneshi Mitusoka, Eiji Inoue, Takashi Okayasu, Hirai Yasumaru, K. I.M. Tae Wook, Soon Goo Kwon, Jong Min Park, Measuring inclination angle of Semi-crawler tractors using MEMS sensor, Journal of the Faculty of Agriculture, Kyushu University, 58, 1, 79-85, 2013.02, In this study, we established a method to calculate inclination angle of moving vehicles from acceleration and angular velocity measured by microelectromechanical systems (MEMS) sensor, which is becoming popular recently due to its ultra-small size and low manufacturing cost. We applied the technique to measure inclination angle of semi-crawler tractor to validate its usefulness. Results from various methods to calculate inclination angle of a vehicle from acceleration and angular velocity data showed that moving average acceleration method and wavelet acceleration method produced results that significantly deviated from the actual inclination angle, while results from angular velocity method and acceleration-angular velocity method were close to the actual inclination angle. Inclination angle calculated by acceleration method in a static state was very similar to the measurement from inclination sensor and was highly accurate, but did not demonstrate sufficient accuracy in dynamic state as the estimated inclination angle was at maximum 10' smaller at inclination angle of 75". In the meanwhile, the inclination angle calculated by angular velocity method showed only small deviation from the sensor measurement even at dynamic state. As a result of measuring inclination of semi-crawler type tractor using MEMS sensor, it was determined that the angular velocity method is the most versatile of the four methods tested as it can not only produce very accurate time series of inclination angle but also be used to easily obtain angular displacement from the angular velocity data obtained. However, error of integration was shown to increase with longer measurement times and it must be addressed by an appropriate solution. Acceleration-angular velocity method also produced similar results as experiments were performed indoors where disturbance factors were few. The inclination angle measurement system using MEMS sensor established in this study can be applied to agricultural vehicles such as tractors as well as to almost all construction and general vehicles with drive system. We expect the system to contribute to development of a safety system that can prevent rollover accidents and quickly respond to them..
116. Jung Seob Choe, Eiji Inoue, Muneshi Mitusoka, Takashi Okayasu, Hirai Yasumaru, Statistical analysis of threshing characteristics of Impact-type rice plant threshing device, Journal of the Faculty of Agriculture, Kyushu University, 58, 1, 69-78, 2013.02, An impact-type threshing device that applies perpendicular force to rice ear was developed in this study. Threshing experiment was performed for a single ear and to a bundle of rice plants. Crop properties and collision conditions were used as input parameters in this experiment to perform multiple regression analysis, thereby estimating threshing rate and percentage of grains with rachis branch. Optimal regression model for estimating threshing rate and percentage of grains with rachis branch was obtained for both single ear and bundle of rice plants. Although all four regression models had low analytical error and verification error, but relative error was high due to insufficient number of datasets and accuracy was low as a result. However, certain extent of estimation was possible for threshing rate. Observing that threshing rate was highly correlated with transverse threshing force and transverse displacement, it was inferred that threshing of rice plant by impact-type threshing device is from perpendicular force acting on rice ears. Although estimation of percentage of grains with rachis branch had low absolute error, accuracy was low because of relative error that is enlarged due to low rate of occurrence. Since percentage of grains with rachis branch was negatively correlated with net's mesh size, we concluded that the mesh size must be made as low as possible to reduce percentage of grains with rachis branch..
117. Sung Won Chung, Yu Shin Ha, Kim Yung Lee, Jong Soon Kim, Jong Min Park, Soon Goo Kwon, Won Sik Choi, Soon Hong Kwon, Muneshi Mitusoka, Eiji Inoue, Takashi Okayasu, Sterilization in hydroponic recycling system using visible light-reactive titanium dioxide photocatalysts, Journal of the Faculty of Agriculture, Kyushu University, 58, 1, 93-98, 2013.02, This research was aimed at developing a hydroponie recycling system using a visible light- reactive titanium dioxide (TiO
2
) photocatalyst. We made a sterilization system for the nutrient solution by utilizing the features of the filters coated with visible light-reactive titanium dioxide photocatalyst. The system is composed of a photocatalyst filter (300×300×20 mm), a 4-tier stair type processing channel (305 mm wide, 2,100 mm long, 30 mm high), a supply tank, a catchment tank, a water pump, a circulation control facility, an insolation sensor, and a data log. We also evaluated the sterilization performance using a number of filters, the initial density of spores in the nutrient solution, the species of spores, flow rates, and the amount of insolation. In the experiment with 20 filters, sterilization performance per 1 filter was 20.3% higher than one per 5 filters. Sterilization performance at a low initial density of spores (26 counts/0.9 mm3) is 23.9% higher than at a high initial density of spores (440.3 counts/0.9 mm3). Colletotrichum was more sensitive to the photocatalyst than Fusarium, and the slow flow rate (0.5 L/min) has more sterilization effects (9.0%) than the fast flow rate (1.0 L/min). The logarithmic relation of the average insolation and lethal intensity of unit spore density is correlated as 0.926 of the coefficient of determination (R2). These results provide valuable information for TlO
2
photocatalytic treatment of waste nutrient solutions under solar light irradiation..
118. Yuta Miyoshi, Kota Hidaka, Takashi Okayasu, Osamu Hirano, Daisuke Yasutake, Kitano Masaharu, Approach to local environment control for stable production of strawberry, IFAC-PapersOnLine, 1, PART 1, 2013.01, In a farmer's strawberry greenhouse, seasonal changes in solar radiation and air conditions (temperature, humidity and CO2 concentration) were measured, and it became clear that the stable yearround production of strawberry was depressed by low temperature and low solar radiation in the cold season and excessively high daytime temperature in the warm season. Furthermore, dew formation in the nighttime, excessively low humidity in the fair daytime and the inappropriate application of CO2 enrichment were also concerned with the depression of stable production. Therefore, a local environment control system was newly developed on the basis of the air circulation and the heat exchange between the constant soil temperature layer and strawberry inter-rows. The system was composed of an underground air pipe (UAP) and inter-row air ducts (IAD) connected to UAP, and UAP was set at a depth of 1.5m where the soil temperature is kept around a temperature suitable for the strawberry growth all the year round. The system can be expected to enable the energy-saving and local control of the ambient air condition of strawberry crops for the stable year-round production..
119. Andri Prima Nugroho, Takashi Okayasu, Eiji Inoue, Hirai Yasumaru, Mitsuoka Muneshi, Development of actuation framework for agricultural informatization supporting system, IFAC-PapersOnLine, 1, PART 1, 2013.01, Agriculture faces many challenges in the production system, such as climate and weather, field conditions, crop types, soils types and conditions, and so on. Farmers consider many aspects to optimize the "on-farm" process by their long-term experiences. Various informatization agricultural supporting systems have been developed using ICT (Information and Communication Technologies) to improve agricultural productivity. Authors have developed the ICT-based agricultural supporting system called the "Agri-eye" in which a field monitoring, crop growth and quality evaluation, work recording, and online data offering and sharing sub-systems were incorporated. On the other hand, an actuation subsystem for controlling and managing agricultural facilities in a greenhouse such as a heater, water pumps, circulation fans, a CO2 generator, etc. has been introduced. In this study, an actuation framework is developed as a useful method for monitoring and controlling local facilities and machineries. The method can be used for controlling particular device with adjusting parameter from Agri-eye server to meet the cultivation requirement. Furthermore, the validity of the developed framework was verified to monitor and control air temperature in laboratory test box..
120. Yasumaru Hira, Keisuke Saruta, Hirohiko Shuto, Takeo Yamakawa, Toshihiro Mochizuki, Eiji Inoue, Takashi Okayasu, Mitsuoka Muneshi, Evaluation of the effects of maturity acceleration of rice straw and nitrogen fertilizer on application of aerobically fermented liquid fertilizer in rice production, Japanese Journal of Crop Science, 10.1626/jcs.82.325, 82, 4, 325-336, 2013.01, [URL], There is growing concern to promote the use of aerobically fermented liquid fertilizer produced from human waste and sludge to reduce the cost, environmental load, and energy consumption in rice production. We tested the maturity accelerating effects on rice straw and effects as a nitrogen fertilizer by applying liquid fertilizer in 2009 and 2010. The maturity accelerating effects were not significant in terms of dry weight, total nitrogen content (T-N), and nitrogen uptake. When liquid fertilizer, which had an ammonium nitrogen (NH4-N) ratio of approximately 70%, was incorporated into the plow layer of the soil as a basal fertilizer, the nitrogen fertilizer effect and panicle number were equivalent to those for chemical fertilizers. However, when liquid fertilizer with a low NH4-N ratio was applied, the dry weight, T-N, and nitrogen uptake were lowered resulting in reduced panicle number. When applied as a top-dressing on the soil surface, nitrogen uptake decreased because of NH4-N loss through volatilization. This decrease in nitrogen uptake may have reduced spikelet number. Nitrogen uptake slowed under the low NH4-N ratio, and nitrogen nutrition conditions deteriorated during the ripening period. This may have lowered 1000-grain weight under the high average temperature conditions in 2010 (26.7°C during the 20-d period after heading). The yield tended to be low because of these reductions in yield components. Nitrogen fertilizer effects were affected by NH4-N ratio, whose fluctuation is considered problematic..
121. Khwantri Saengprachatanarug, Masami Ueno, Eizo Taira, Takashi Okayasu, Modeling of soil displacement and soil strain distribution under a traveling wheel, Journal of Terramechanics, 10.1016/j.jterra.2012.06.001, 50, 1, 5-16, 2013.01, [URL], The empirical Gaussian-based mathematical model of the soil displacement increment under a traveling wheel was extended to be applicable to any depth of soil layer under the ground contact surface of the wheel. The unknown coefficients were obtained by least mean-square fitting with the soil displacement curve measured through a sophisticated laboratory soil bin test. Those coefficients were then re-derived as a function of depth. The movement of soil particles at the ground contact surface was modeled by dividing movement into two kinds; first, the free movement of soil particles before contact with the wheel and the movement of the particles after they are separated from the wheel surface and, second, soil movement during attachment to the wheel surface. By combining the models for the ground contact surface of the wheel with that for all soil layers, an extended model that can describe soil displacement increment in both vertical and horizontal directions using one equation was established. The predicted results obtained using the extended model fitted quite well with the measured values. The predicted strain increment distributions also show the same trends as the measured distributions..
122. Keisuke Saruta, Hirai Yasumaru, Kodai Tanaka, Eiji Inoue, Takashi Okayasu, Mitsuoka Muneshi, Predictive models for yield and protein content of brown rice using support vector machine, Computers and Electronics in Agriculture, 10.1016/j.compag.2013.09.003, 99, 93-100, 2013.01, [URL], Rice production in Japan is facing problems of yield and quality instability owing to recent climate changes, aging of farmers, and a decrease in the farmer population. Thus, it is becoming important to develop an improved rice production technology that utilizes collected data about rice production rather than relying on the conventional technology that is based on the experience and knowledge of individual farmers. We developed predictive models for yield and protein content of brown rice that can provide useful knowledge to support farmer's management decision-making, utilizing data sets from 47 paddy fields where rice was produced under various environments and management styles. Support vector machines (SVMs) were applied to build the predictive models based on explanatory variables representing the growth and nutrition conditions after the heading stage and the meteorological environment after the late spikelet initiation stage. The models achieved quantitative accuracy that was within approximately 1tha-1 in yield for 85.1% of the total data sets and within 0.8% in protein content for 76.6% of the total data sets, respectively. Further, patterns of explanatory variables classified in three classes of yield and protein content, which were visualized by the predictive models, were reasonable in terms of knowledge of crop science. We found that the predictive models using SVMs had the potential to describe a relation between yield or protein content and multiple explanatory variables that reflected diverse rice production in actual fields, and could provide useful knowledge for decision-making of topdressing and basal fertilization..
123. Takashi Okayasu, Prima Nugroho Andri, 尾崎 彰則, Mitsuoka Muneshi, Teruaki Nanseki, Eiji Inoue, Hirai Yasumaru, 変化点分析法を用いた圃場環境情報の特徴量抽出とその妥当性の検証, 農業情報研究, 10.3173/air.22.174, 22, 3, 174-182, 2013, [URL], Environmental data are measured and collected by simple monitoring devices installed in agricultural fields. These data are very important not only for understanding and predicting factors such as the growth of crops and the occurrence of pests and diseases, but also for optimizing agricultural production processes such as planting, irrigation, fertilization, pest control, and harvesting. However, the amount of data stored in agricultural information databases is rapidly increasing owing to an increase in the number of monitoring devices and sensors installed in such devices. To properly detect characteristic values from such a vast amount of data, it is necessary to develop new numerical technologies and methods. We developed a simple field monitoring system to establish field observations, production optimization, and information sharing between farmers. We also developed and applied a change point analysis program based on the singular spectrum transformation to conduct change point analyses of the field environmental data measured by the monitoring devices. The calculated change point values were then verified through a comparison with farm data recorded by a corporative farmer in the feasibility study..
124. Okayasu, T., Mitsuoka, M., Andri, P.N., Yoshida, H., Nanseki, T. and Inoue, E, Change Point Analysis for Environmental Information in Agriculture, Proc. AFITA/WCCA2012, Seminar20-03(6 pages), 2012.09.
125. Andri, P.N., Okayasu, T., Fushihara, H., Mitsuoka, M. and Inoue, E., Development of Intelligent Control System for Greenhouse, Proc. AFITA/WCCA2012, Seminar16-04(7 pages), 2012.09.
126. Yusaku Yamauchi, Hirai Yasumaru, Keisuke Saruta, Takeo Yamakawa, Eiji Inoue, Takashi Okayasu, Mitsuoka Muneshi, Evaluation of a multiple linear regression model for the prediction of panicle number in rice, Journal of the Faculty of Agriculture, Kyushu University, 57, 2, 421-426, 2012.09, In Japan, rice production technology must be developed to meet stable yield and quality targets. This objective is important because of the demand for high quality rice by consumers, the necessity of enhancing Japan's international competitive power, and a declining trend in the production of first grade rice. To achieve stable yield and quality, it is important to control panicle number appropriately since it is a primary factor to determine rice yield and quality. In this study, a multiple linear regression model was built to predict panicle number, which can support the decision-making process of farmers in agricultural practice. Surveys of 33 paddy fields were conducted in the Fukuoka Prefecture in 2010-2011. Data regarding influential factors on panicle number, such as solar radiation, water temperature, and exchangeable ammonium (eNHJ content in the soil, were collected and used for building the model as candidates of the explanatory variable. As the results, eNH, content in the soil at the beginning of tillering stage and accumulated amount of daily solar radiation during the tillering stage were selected as explanatory variables. The adjusted coefficient of determination was 0.448 and RMSECV was 2.49. In the prediction model, eNH, content in the soil at the beginning of the tillering stage was selected as an explanatory variable to represent inorganic nitrogen supply. In comparison, this variable does not reflect the inorganic nitrogen supplied throughout the tillering stage. This difference resulted in a large error in the field with organic fertilizer application, as the manner of inorganic nitrogen release is different to that of typical fields in the survey area that are subject-ed to chemical fertilizer application..
127. Okayasu, T., Yoshida, H., Andri, P.,N., Mitsuoka, M., Inoue, E., Feasibility Study on Informatization Agricultural Supporting System and Evaluation of its Validity, CIGR-AgEng2012, Web(6 pages), 2012.07.
128. Okayasu, T., Morishita, K., Terao, H., Muneshi, M., Inoue, E., Fukami, K., Modeling and prediction of soil cutting behavior by a plow, CIGR-AgEng2012, C2290(6 pages), 2012.07.
129. Okayasu, T., Andri, P.,N., Fushihara, Hirano, O., Yoshida, H., Inoue, E., Development of intelligent irrigation system for greenhouse, Proc. 6th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM(6 pages), 2012.06.
130. Terao, H., Okayasu, T., Fkuda, K. Fukami, K., Mitsuoka, M., Inoue, E., Strength evaluation of bearing in sidedisk for cutting small ditches by finite element method, Proc. 6th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM(6 pages), 2012.06.
131. Okayasu, T. Mitsuoka, M., Andri P.N., Inoue, E., Application of Change Point Analysis for Long-term Environmental Monitoring Data, Proceeding on International Workshop on ICT in Geo-Engineering, 147-153, 2012.05.
132. Soetiarso, L. Goenadi, S., Andri P.N., Okayasu, T., Monitoring of Hydraulic Gradient in Agricultural Land-use using Grid Wireless Sensor Network, Proceeding on International Workshop on ICT in Geo-Engineering, 117-124, 2012.05.
133. 大庭裕史,岡安崇史,寺尾悠希,深見公一郎,渡辺輝夫,光岡宗司,井上英二, 小明渠作溝用サイドディスク設計のための有限要素法の適用性に関する研究, 農業機械学会誌, 74(3),207-212, 2012.05.
134. Jongmin PARK, Ghiseok KIM, Soonhong KWON, Sungwon CHUNG, Soongoo KWON, Wonsick CHOI, Muneshi Mitsuoka, Eiji INOUE, Takashi OKYASU, Jungseob CHOE., Finite Element Analysis of Corrugated Board under Bending Stress, Journal of the Faculty of Agriculture Kyushu University, 57(1), 181-188, 2012.02.
135. Jongmin Park, Ghiseok Kim, Soonhong Kwon, Sungwon Chung, Soongoo Kwon, Wonsick Choi, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Jungseob Choe, Finite element analysis of corrugated board under bending stress, Journal of the Faculty of Agriculture, Kyushu University, 57, 1, 181-188, 2012.02, Corrugated board is an engineering structure, whose strength characteristics depend on the cross-section geometry and the material properties of liner and corrugated medium. Therefore, the board combination (combination of material for preparing corrugated board) of corrugated boards should be optimized with considering the quality characteristics of corrugated board demanded to achieve the optimum packaging design. The board combinations of corrugated boards can be determined by employing the configuration method for the paperboard stiffness and the basis weight. The results of board combinations can greatly affect the buckling resistance and compression strength of the box. 11,15 In order to analyze the effect of the configuration method for the board stiffness and the basis weight on the flexural stiffness of corrugated board, we performed experiments based on cost- and time-consuming procedures. However, by using a simulation method such as finite element analysis (FEA) has the advantages such as saving of the time and cost in experiments and sample production as well as detailed analysis by adjusting several parameters. In the case of the simulation method, the estimation of reliability and reproducibility of the results should be strongly considered. In this study, we observed the strength-optimal design conditions for the corrugated board combinations by analyzing the flexural stiffness index (FSI). The FEA method was used in the study using the four-point loading conditions. We found that the difference between the FEA result and the test results were approximately 18-31%. However, it was estimated that the variations in FSI estimated by using both methods are similar. Therefore, we expect that the flexural balance for different board combinations would be successfully analyzed on the basis of the qualitative comparison of FSI values corresponding to the combinations when the stiffness for each of the liner and the corrugating medium are assumed to be with 2-3 levels..
136. 宮嵜朋浩,岡安崇史,杉本知史,井上英二, 農用車両走行による諫早湾干拓土壌の構造と力学特性の変化, 農作業研究, 47(1),11-17, 2012.01.
137. Takashi Fukushima, Eiji Inoue, Mitsuoka Muneshi, Takashi Okayasu, Kunio Sato, Collision vibration characteristics with interspace in knife driving system of combine harvester, Engineering in Agriculture, Environment and Food, 10.1016/S1881-8366(12)80024-3, 5, 3, 115-120, 2012.01, [URL], It is necessary to develop a design theory of the knife driving system of combine harvesters in order to derive the control parameters of the balance weights used for vibration reduction. A collision vibration model of the knife driving system that is equipped with a slider-crank mechanism was constructed in order to examine the influence of the interspace that arises at the joint of the drive knife and the end of the link arm. The simulation result revealed that the harmonic frequency components varied with an increase in the width of the interspace although the highest harmonic frequency in the simulation without the interspace was three times the crank wheel rotation frequency. However, the vibration reduction by the balance weight was not dependent on the width of the interspace..
138. Yuko Ueka, Masami Matsui, Eiji Inoue, Ken Mori, Takashi Okayasu, Mitsuoka Muneshi, Turbulent flow characteristics of the cleaning wind in combine harvester, Engineering in Agriculture, Environment and Food, 10.1016/S1881-8366(12)80022-X, 5, 3, 102-106, 2012.01, [URL], The flight of separated straws is thought to affect the cleaning wind of a combine harvester. To comprehend the turbulent flow characteristics of the cleaning wind and its passage through the grains, the cleaning wind velocity is measured by particle image velocimetry and laser Doppler velocimetry. The flow of the cleaning wind is blocked by the grains, and therefore the distribution of wind velocity changes. It is found that the energy loss of the cleaning wind is not a result of turbulent flow. The wall friction and the pressure change observed as a result of the shape and the friction loss in the grains are the main considerations while calculating the energy loss of the cleaning wind in combine harvester..
139. Eiji Aoki, Ken Kudo, Akira Fukuda, Tsuneo Nakanishi, Shigeaki Tagashira, Takashi Okayasu, Naoyuki Tsuruda, Satoru Yamasaki, Yasuhito Imura, Study on knowledge management platform about the field of agricultural infomatization, 2012 6th International Conference on Complex, Intelligent, and Software Intensive Systems, CISIS 2012
Proceedings - 2012 6th International Conference on Complex, Intelligent, and Software Intensive Systems, CISIS 2012
, 10.1109/CISIS.2012.149, 705-710, 2012, [URL], In the region of Japan, broadband network and informatization have spread. However the field of agriculture has not come willingly. The infrastructure that has not been enough in mountainous areas, but various initiatives of computerization are being started using production and distribution as the subjects. Since this began in reality, there are still insufficient matters that have been resolved in regards to the technical validations and cost effectiveness. Therefore necessitates pouring in a tremendous amount of expertise, possibility is ICT and its related technologies of sensors. In our research and developments, we create demo hardware for the experiment using in the farm collected data. On the other hand, making study group with farmers for accumulation of data and experience. That visualized information configure to the platform of knowledge management..
140. Jongmin PARK, Ghiseok KIM, Hakjin KIM, Soongoo KWON, Muneshi Mitsuoka, Eiji INOUE, Takashi OKYASU, Jungseob CHOE., Characteristics of Vibration Transmissibility for Corrugated Paperboard, Journal of the Faculty of Agriculture Kyushu University, 56(2), 327-333, 2011.11.
141. M. A. Rabbani, T. Tsujimoto, Mitsuoka Muneshi, Eiji Inoue, Takashi Okayasu, Prediction of the vibration characteristics of half-track tractor considering a three-dimensional dynamic model, Biosystems Engineering, 10.1016/j.biosystemseng.2011.07.013, 110, 2, 178-188, 2011.10, [URL], A dynamic three-dimensional model was constructed for a half-track tractor that considers its bounce, pitch, and roll motions in order to clarify the tractor's vibration characteristics. Driving experiments were conducted in which the tractor was driven on a solid asphalt road surface in order to investigate its vibration characteristics and to verify the validity of an analysis based on motion equations that were formulated from the proposed dynamic model. The experiments were conducted with a half-track tractor apparatus equipped with twelve accelerometers for the measurement of 6 DOF of acceleration of the tractor's centre of gravity. The discrete time series of the measured data was resolved and reconstructed by wavelet analysis. The model was verified using the fixed lug phase difference between the left and the right crawler systems for each combination of three location arrangements of the track rollers and seven levels of tractor speed. Results showed that the acceleration of the centre of gravity for the bounce, pitch, and roll motions was at a minimum when the track rollers were set equidistant from one another. The acceleration caused by the bounce and pitch motions decreased with an increase in the lug phase difference, while the acceleration caused by the roll motion increased with an increase in the lug phase difference. The results further suggested that the proposed three-dimensional dynamic model could be improved by incorporating into it the lug phase differences that change during actual tractor driving, instead of a constant lug phase difference..
142. M.A. Rabbani, T. Tsujimoto, M. Mitsuoka, E. Inoue, T. Okayasu, Prediction of the vibration characteristics of half-traced tractor condering a three-dimensional dynamic model, Biosystems Enginering, 110(2), 178-188, 2011.09.
143. Okayasu, T., Yoshida, H., Afroja, K., Ozaki, A., Mitsuoka, M., Inoue, E., Development of Simple Field Monitoring System for Agriculture and Evaluation of its Validity, Proc. Int. Conf. Env. Aspects Bangladesh, 205-207, 2011.09.
144. Jongmin Park, Ghiseok Kim, Hakjin Kim, Soongoo Kwon, Muneshi Mitusoka, Eiji Inoue, Takashi Okayasu, Characteristics of vibration transmissibility for corrugated paperboard, Journal of the Faculty of Agriculture, Kyushu University, 56, 2, 327-333, 2011.09, Corrugated fiberboard are typically lightweight and inexpensive with high stiffness-to-weight and strength-to-weight ratios as an environmental-friendly packaging materials. In order to optimize the application of corrugated paperboard for packaging cushioning materials, it is essential that both a vibration transmissibility test and drop shock test be completed for the transmissibility-frequency curve and dynamic cushion curve respectively. This paper deals with the characterization of properties of corrugated paperboard relevant to its application for protective packaging in transportation, such as vibration transmissibility, resonant frequency, damping ratio, and maximum dynamic stress. The main feature of the paper is the evaluation on the vibration transmissibility of corrugated paperboard with corrugation shape and the equilibrium atmospheric conditions by a sinusoidal sweep vibration test. Additionally, damping ratio and maximum dynamic stress were evaluated by linear vibration theory. All the works provide basic data relevant to its application for protective packaging in transportation..
145. 光岡宗司, 武岡達, 辻本規, 井上英二, 岡安崇史, 崔重燮, 転輪とゴム履帯との非線形作用特性を考慮したセミクローラ式トラクタの力学モデル, 農業機械学会九州支部誌, 60, 1-6, 2011.08.
146. 吉田博通,岡安崇史,平野修,小野聖一朗,安部貞昭,清水宣雄,光岡宗司,井上英二,崔 重燮, 情報化農業支援システムのハウス栽培いちごの生産管理への応用に関する基礎的研究, 農業機械学会九州支部誌, 60, 7-12, 2011.08.
147. Okayasu, T., Yoshida, H., Miyazaki, T., Nanseki, T., Mitsuoka, M., Inoue, E., Feasibility Study on Field Monitoring and Work Recording System in Agriculture, Proc. ASABE2011, Web, 2011.08.
148. Miyazaki, T., Okayasu, T., Inoue, E., Prediction of compaction behavior of heavy clayey soil beneath an off-road vehicle, Proc. ASABE2011, Web, 2011.08.
149. 大庭裕史,岡安崇史,寺尾悠希,深見公一郎,渡辺輝夫,光岡宗司,井上英二, 小明渠作溝用サイドディスク設計への有限要素法の適用に関する基礎的研究, 農業機械学会九州支部誌, 59, 1-5, 2011.03.
150. Takashi Okayasu, Hiromichi Yoshida, Tomohiro Miyazaki, Teruaki Nanseki, Mitsuoka Muneshi, Eiji Inoue, Feasibility study on field monitoring and work recording system in agriculture, American Society of Agricultural and Biological Engineers Annual International Meeting 2011
American Society of Agricultural and Biological Engineers Annual International Meeting 2011, ASABE 2011
, 2, 1652-1662, 2011, Simple field monitoring system for optimizing and improving agricultural production process and management is developed by the built-in mail sender data logger unit with some weather and field monitoring sensors. In this monitoring system, all the monitoring data are once transferred and stored to mail servers. Thereafter the data are transferred periodically to the agricultural information database system. The database system was fully developed using open software such as apache (web server), MySQL, PHP, Java, CMS (Contents Management System) and so on. The stability of the monitoring system was verified using more than 20 monitoring units at four test sites where weather, crop type and farm size are different. On the other hand, work recording system to manage and optimize current production process was also developed and integrated to the developed database system. A list of farming processes and schedules was arranged flexibly by a farmer thorough a web browser. All the process data were entered into the information database by using mobile device and/or PC. The availability and validity of the developed recording system were verified by feasibility studies in the real farming sites..
151. Khwantri Saengprachatanarug, Masami Ueno, Eizo Taira, Takashi Okayasu, Modeling of soil displacement and soil strain distribution under the traveling wheel, 17th International Conference of the International Society for Terrain Vehicle Systems 2011, ISTVS 2011
17th International Conference of the International Society for Terrain Vehicle Systems 2011, ISTVS 2011
, 12-24, 2011, The empirical Gaussian-based mathematical model of soil displacement increment under the traveling wheel was extended to be applicable to any depth of soil layer under the ground contact surface of the wheel. The unknown coefficients were obtained by least mean-square fitting with the soil displacement curve measured through laboratory sophisticated soil bin test. Then those coefficients were re-derived as a function of depth. The movement of soil particles at the ground contact surface was modeled by dividing into 2 kinds; first, the free movement of soil particles before contact with the wheel and the movement of the particles after they are separated from the wheel surface and the second type represent soil movement during attachment to the wheel surface. By combining the models for the ground contact surface of the wheel with that for all soil layers, the extended model that can describe soil displacement increment in both the vertical and horizontal directions using one equation was established. The predicted results obtained using the extended model fitted quite well with the measured values. The predicted strain increment distributions show the same trends as the measured distributions..
152. Tomohiro Miyazaki, Takashi Okayasu, Eiji Inoue, Prediction of compaction behavior of heavy clayey soil beneath an off-road vehicle, American Society of Agricultural and Biological Engineers Annual International Meeting 2011
American Society of Agricultural and Biological Engineers Annual International Meeting 2011, ASABE 2011
, 4, 2666-2675, 2011, Soil compaction is one of the major subjects in a well-mechanized modern agricultural system. In order to reduce the risk of soil compaction, the mechanical impacts to topsoil and subsoil during agricultural machinery operations have to be controlled. Soil compaction test using an off-road vehicle was conducted in the reclamation farmland at Isahaya bay, Nagasaki, Japan. The farmland was formed by sedimentary heavy clayey soil having high water-holding capacity and strong cohesion. In all the tests, the penetration resistance (cone index) of the soil and the bulk density before and after the vehicle running was measured in the field. The detail of soil mechanical properties was obtained from typical soil tests such as the standard compression, oedometer and triaxial compression test, respectively. On the other hand, an unconventional elastoplastic constitutive model for soils having the structure and cohesion was proposed by the superloading-yield/subloading surface model with Hashiguchi and Mase concept (2007). The validity of the model was evaluated by comparisons with the test data mentioned above..
153. 上村巧,岡安崇史,加利屋義広,岡勝,鹿島潤,井上英二, 受口切りの不一致やツル幅の不均一が伐倒方向と作業の安全性に及ぼす影響, 森林利用学会, 25(4), 207-214, 2010.10.
154. RABBANI, M.A., TAKEOKA, S., MITSUOKA, M., INOUE, E., FUKUSHIMA, T., OKAYASU, T., Simulation for Vertical Dynamic Loading Forces on Track Rollers of the Half-tracked Tractor Based on Nonlinear Voigt's Model, (EAEF) ,Vol.3 ,(4) ,119-126,2010.11., Engineering in Agriculture Environment and Food, 119-126, 2010.10.
155. Okayasu, T., Kamitsuji, N., Murakami, T., Miyazaki, T., Mitsuoka, M., Inoue, E., Fukami, K., Soil Compaction Analysis on Structured Cohesive Soft Ground, Proc. 9th Asia-Pacific Conf. ISTVS, CD-ROM, 2010.09.
156. Ueka, Y., Matsui, M., Inoue, E., Mori, K., Okayasu, T., Fluid Analysis of Cleaning Wind in Combine Harvester, Proc. 5th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2010.04.
157. Fukami, K. Watanabe, T., Sasaki, Y., Tanio, M., Tsutiya, S., Tasaka, K., Okayasu, T., Inoue, E., Ohba, H., Kamitsuzi, N., Study on Durability Improvement of the Shallow Tillage Seeding Machine with Cutting Small Ditches - Measurement of an acting force on the bearing part of the side disk to cut small ditch, Proc. 5th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2010.04.
158. Ashik, R.M., Mitsuoka, M., Takeoka, S., Inoue, E., Fukushima, T., Okayasu T., Dynamic Model of Half-Tracked Tractor Considering the Nonlinear Voigt Model, Proc. 5th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2010.04.
159. Miyazaki, T., Okayasu, T., Inoue, E., Tractor Running Tests at Isahaya Bay Reclamation, Proc. 5th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2010.04.
160. Okayasu,T., Yamabe, N., Marui, A., Miyazaki, T., Mitsuoka, M., Inoue, E., Development of Field Monitoring and Work Recording System in Agriculture, Proc. 5th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2010.04.
161. Mitsuoka, M., Tsuzimoto, T., Ashik, R.M., Inoue , E., Fukushima, T., Okayasu, T., Three Dimension Model of Vibration Characteristics of the Half-tracked Tractor, Proc. 5th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2010.04.
162. Nakano, K., Takahashi, C., Oba, S., Shimazu, T., Okayasu, T., Investigation of Chilling Sensitivity and Effect of Instant Water Soaking Treatment on the Quality of Amaranth Leaves, Proc. 5th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2010.04.
163. 宮嵜朋浩・岡安崇史・山田寧直・井上英二, 諫早湾干拓土壌におけるトラクタ走行で生じる踏圧現象, 農作業研究, 45(1), 29-35, 2010.02.
164. M. A. Rabbani, Susumu Takeoka, Mitsuoka Muneshi, Eiji Inoue, Takeshi Fukushima, Takashi Okayasu, Simulation for vertical dynamic loading forces on track rollers of the half-tracked tractor based on nonlinear Voigt's model, Engineering in Agriculture, Environment and Food, 10.1016/S1881-8366(10)80003-5, 3, 4, 119-126, 2010.01, [URL], Experiments to measure the vertical dynamic loading forces acting on the track rollers of a half-tracked tractor were conducted by using strain gauges. In addition, a driving simulation model was constructed to predict the vertical dynamic loading forces acting on the track rollers as the tractor ran on an asphalt road surface. A twodimensional model to evaluate the vibration characteristics of the half-tracked tractor is discussed. It was modified and improved by considering the linear and nonlinear interactions of the rubber crawler with the track roller as well as the roller's location arrangement..
165. Okayasu, T., Yamabe,N. Mrui, A. Mitsuoka, M., Inoue, E., Development of simple field monitoring system for agricultural production and management, IWABE2009, 320-327, 2009.12.
166. Okayasu, T., Miyazaki, T., Kamitsuji, N., Mitsuoka, M., Inoue, E., Fukami, K., Numerical Soil Compaction Analysis on Structured Soft Ground, ISTRO2009, Izmir, T4-011, 1-8, 2009.06.
167. Fukami, K., Watanabe, T., Tanio, M., Masuda, K., Okayasu, T. Inoue, E., Kamitsuji, N., Ohba, H., Study on Durability Improvement of the Shallow Tillage Seeding Machine with Cutting Small Ditches, ISTRO2009, Izmir, T1-017, 1-5, 2009.06.
168. 上村巧,岡安崇史,鹿島潤,佐々木達也,岡勝,加利屋義広,井上英二, 倒伏初期における追口高さが内部応力に与える影響, 森林利用学会, 24(1), 2009.04.
169. Mistsuoka, M., Inaba, S., Inoue, E., Fukushima, T., Okayasu, T., Mori, K., Dynamic model of an agricultural rubber crawler vehicle with nonlinear spring (part 1) -Investigation of the nonlinear interaction between a track roller and an agricultural rubber crawler, J. JSAM, 70(5), 48-54, 2008.09.
170. Mistsuoka, M., Inaba, S., Inoue, E., Fukushima, T., Hara, S., Okayasu, T., Mori, K., Prediction and evaluation of vibration characteristics of an agricultural rubber crawler vehicle equipped with movable track rollers, J. JSAM, 70(5), 41-47, 2008.09.
171. 平田真理,岡安崇史,羽田野梨絵,山邉信利,安武隼人,内田 進,稲葉繁樹,光岡宗司,井上英二, ハイパースペクトルカメラ画像を用いた水稲の生育診断・品質評価に関する研究, 農業機械学会九州支部誌, 57, 13-18, 2008.08.
172. 松浦大海・古野裕子・松井正実・井上英二・森 健・岡安崇史, 乱流モデルを導入した選別風の数値流体解析, 農業機械学会九州支部誌, 57, 7-12, 2008.08.
173. Yamagata, Y., Okayasu, T., Eguchi, H., Sinkai, S., Furuno, Y., Mitsuoka, M., Inoue, E., Imamura, E., Application of Discrete Element Method to Solve Shaking Separation Mechanisms in Head-Feeding Combine Harvester, Proc. 4th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2008.05.
174. Okayasu, T., Matsuda, H., Furuno, Y., Kamitsuji, N., Mitsuoka, M., Inoue, E., Ueno, M., Fukami, K., Computational Mechanical Consideration on Soil Compaction Behavior due to Wheel Traffics after Tillage, Proc. 4th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), CD-ROM, 2008.05.
175. 江口 寛,岡安崇史,山形友佑,新開聡,光岡宗司,井上英二,今村英一, 自脱型コンバイン揺動選別部の性能向上のための数値解析法の開発, 九州大学農学芸誌, 63(1), 47-56, 2008.03.
176. 羽田野梨絵,岡安崇史,平田真理,山邉信利,中司 敬,光岡宗司,井上英二, 営農支援のための圃場気象環境情報モニタリングシステムの開発に関する基礎的研究, 九州大学農学芸誌, 63(1), 57-63, 2008.03.
177. Furuno, Y., Matsui, M., Inoue, E., Mori, K., Okayasu, T. Fukata, R., Analysis of Winnorw Mechanism on the Basis of Particle-Particle/Particle-Airflow Interaction (Part 1)-Dispersion Characteristics of Paddy Grains/Straws-, J. Jpn. Soc. Agr. Mach., 70(1), 65-71, 2008.01.
178. Okayasu, T., Matsuda, H., Furuno, Y., Mitsuoka, M., Inoue, E., Hashiguchi, K., Elastoplastic deformation analysis on soil compaction by wheel traffics, Plasticity 2008, 373-375, 2008.01.
179. S. Ozaki, K. Hashiguchi, Takashi Okayasu, D. H. Chen, Finite element analysis of particle assembly-water coupled frictional contact problem, CMES - Computer Modeling in Engineering and Sciences, 18, 2, 101-119, 2007.04, In order to analyze precisely not only the elastoplastic deformation phenomenon of saturated particle assembly such as soils, grains, powdered and tablet medicines or three dimensional cellular materials, but also the frictional sliding phenomenon between saturated particle assembly and other bodies, a particle assembly-water coupled finite element program, that incorporates both the subloading surface and the subloading-friction models, is developed. Subsequently, simulations of the compaction behavior of saturated particle assembly under strain rate control are performed. It is revealed by the numerical experiment adopting the finite element program that the frictional sliding behavior of the contact boundary influences both the deformation behavior and the pore water flow behavior in the saturated particle assembly..
180. Okayasu, T., Hadano, R., Hirata, M., Yamabe, N., Yasutake, H., Nakaji, K., Mitsuoka, M., Inoue, E., Utilization of Hyperspectral Imaging Technique for Low Protein Rice Production in Kasuya, Fukuoka, Int. S. Agr. Struct. Agr. Engng. 2007, 259-265, 2007.01.
181. Okayasu, T., Matsuda, H., Furuno, Y., Mitsuoka, M., Inoue, E., Hashiguchi, K., Ueno, M., Fukami, K., Elastoplastic finite element analysis on soil compaction phenomena by wheel traffics, Int. WS Agri. Biosy. Engng., 2007.01.
182. 岡安崇史,大山将史,古野裕子,光岡宗司,井上英二,橋口公一, 構造を有する地盤の転圧現象に関する弾塑性有限要素解析, 応用力学論文集(土木学会), 10, 323-300, 2007.01.
183. Ozaki, S., Hashiguchi, K., Okayasu, T. and Chen, D.H., Finite Element Analysis of Particle Assembly-water Coupled Frictional Contact Problem, CMES, 18, 2, 101-119, 2007.01.
184. Fukami, K., Ueno, M., Hashiguchi, K., Okayasu, T., Mathematical models for soil displacement under a rigid wheel, J. Terramech., 43, 287-301, 2007.01.
185. 橋口公一,岡安崇史,尾崎利行, 超過応力テンソル導入による接線粘塑性ひずみ速度を考慮した超過応力モデル, 日本機械学會論文集A編, 73(725),151-158, 2007.01.
186. Koichi Hashiguchi, Takashi Okayasu, Toshiyuki Ozaki, Overstress model with tangential-viscoplastic strain rate by incorporation of overstress tensor, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 73, 1, 151-158, 2007.01, The elastoplastic stress is first defined as the stress which evolves as the actual strain rate is induced in an imaginary quasi-static process of elastoplastic deformation, while internal variables evolve with the viscoplastic strain rate calculated by the viscoplastic constitutive equation. Further, the novel variable "overstress tensor" reaching the current stress from the elastoplastic stress is defined. Then, the overstress model is extended so as to describe also the tangential viscoplastic strain rate induced by the overstress tensor component tangential to the yield surface. Furthermore, the viscoplastic strain rate due to the change of stress inside the yield surface is incorporated by adopting the concept of the subloading surface which falls within the framework of the unconventional elastoplasticity describing the smooth elastic-plastic transition fulfilling the smoothness and continuity conditions..
187. M. Hira, K. Hashiguchi, M. Ueno, Takashi Okayasu, Deformation behavior of Shirasu soil by the extended subloading surface model, Lowland Technology International, 8, 1, 37-46, 2006.06, This study is aimed at evaluation of the deformation behavior of Shirasu soil (volcanic sandy soil) for reclamation and embankment construction, using elastoplastic constitutive equation based on the subloading surface model with the rotational hardening. Test results for isotropic consolidation and monotonic/cyclic loading-unloading compression with several lateral stresses under the drained conditions for various initial void ratios are reported. Further, the simulation by the constitutive equation based on the extended subloading surface model is compared with the test results. High applicability of the constitutive equation for the prediction of mechanical behavior of Shirasu soil for a geo-material at the lowland in the southern Kyushu is verified by the comparison..
188. 福島崇志,岡田淳,井上英二,光岡宗司,稲葉繁樹,岡安崇史, セミクローラ式トラクタの転動抵抗を考慮した振動解析モデルとその評価, 農業機械学会誌, 68(5), 71-77, 2006.01.
189. Fukushima, T., Inoue, E., Mitsuoka, M., Matsui, M., Okayasu, T., Vibration Characteristics and Modeling of Knife Driving System of Combine Harvester(Part3)-A Dynamic Model of the Knife Driving System-, J. Jpn. Soc. Agr. Mach., 68(5), 65-70, 2006.01.
190. Fukushima, T., Inoue, E., Mitsuoka, M., Matsui, M., Okayasu, T., Vibration Characteristics and Modeling of Knife Driving System of Combine Harvester(Part2)-Recurrence Plots and Trajectory Considering Frequency Components-, J. Jpn. Soc. Agr. Mach., 68(5), 59-64, 2006.01.
191. Fukushima, T., Inoue, E., Mitsuoka, M., Matsui, M., Okayasu, T., Vibration Characteristics and Modeling of Knife Driving System of Combine Harvester(Part1)-Frequency Resolution of Time Series by Wavelet Analysis-, J. Jpn. Soc. Agr. Mach., 68(5), 52-58, 2006.01.
192. 古野裕子,松井正実,井上英二,森健,岡安崇史, 選別風を受ける藁の飛散範囲シミュレーション., 農業機械学会誌, 68(3), 53-60, 2006.01.
193. Okayasu T., Ozaki, T., Hashiguchi, K., Inoue, E., Elastoplastic finite element analysis on uplift problem of ground anchor subject to repeated loading, Proc. 4th Asian-Joint Sympo. Geotech. & Geoenviron. Engng. (JS-Dalian 2006), (in press), 2006.01.
194. Okayasu, T., KInoshita, K., Shimomura, T. Hashiguchi, K., Inoue, E.., Finite element analysis on deformation behavior of metallic body, Proc. 35th Solid Mech. Conf., 165-166, 2006.01.
195. Setouchi, H., Hashiguchi, K., Shikanai, T., Okayasu, T., Extended tangential-subloading surface model for general loading behavior of soils: application to nonproportional loadings, Soils and Foundations., 46(4), 449-464, 2006.01.
196. Hideki Setouchi, Koichi Hashiguchi, Takeshi Shikanai, Takashi Okayasu, Extended tangential-subloading surface model for general loading behavior of soils
Application to nonproportional loadings, Soils and Foundations, 10.3208/sandf.46.449, 46, 4, 449-463, 2006.01, [URL], The conventional elastoplastic model premising that the interior of yield surface is a purely elastic domain is incapable of describing the plastic deformation by the rate of stress inside the yield surface. Thus, it is inapplicable to the description of cyclic loading behavior. Besides, the traditional elastoplastic model is independent of the stress rate component tangential to the yield surface. Therefore, it predicts an unrealistically high stiffness modulus for non- v proportional loading process deviating significantly from proportional one. The extended tangential-subloading surface model proposed by Hashiguchi and Tsutsumi (2001) would be capable of describing the cyclic loading behavior and the inelastic strain rate induced by the stress rate component tangential to the subloading surface. In this article, the extended tangential-subloading surface model is applied to the prediction of deformation behavior of sands subjected to various loading ranging from proportional to cyclic nonproportional loading. The validity is verified by comparing with the various test data. Then, it is revealed that the incorporation of the strain rate due to the stress rate component tangential to the subloading surface is of importance for the description of nonproportional loading behavior..
197. Koichiro Fukami, Masami Ueno, Koichi Hashiguchi, Takashi Okayasu, Mathematical models for soil displacement under a rigid wheel, Journal of Terramechanics, 10.1016/j.jterra.2005.05.005, 43, 3 SPEC. ISS., 287-301, 2006.01, [URL], Soil-wheel interaction especially soil deformation caused by the wheel motion was investigated experimentally using a sophisticated soil bin test apparatus and an on-line measurement system for soil displacement. Based on these test results, characteristics of soil deformation were summarized focusing on the behavior and distribution of displacement increment vectors. Mathematical models were examined in order to describe the displacements of soil particles. Properties of the displacement loci are described. The magnitude of the displacement increment vector, its horizontal and vertical components are discussed, and characteristics of these distributions with respect to the relative horizontal distance from the vertical centerline of the wheel to the target point are clarified. Shapes of these distribution curves were closely similar to those of the derivatives of a Gaussian function. A distribution curve of the horizontal displacement increment had two peaks and that of the vertical one had three peaks. Based on the results, mathematical models for those displacement increments were proposed by employing a Gaussian function through multiplication of a linear function and a quadratic function. Predicted distributions and displacement loci of the models agreed with high accuracy to the measured values. The mathematical models were extended taking into consideration the wheel slip. The predicted distributions according to test conditions agreed very well to the measured results..
198. K. Hashiguchi, Takashi Okayasu, K. Saitoh, Rate-dependent inelastic constitutive equation
The extension of elastoplasticity, International Journal of Plasticity, 10.1016/j.ijplas.2004.04.001, 21, 3, 463-491, 2005.03, [URL], A rate-dependent inelastic constitutive equation is formulated by extending the elastoplastic constitutive equation so as to retain the latter's mathematical structure and thus reduce to the latter equation at an infinitesimal rate of deformation. That structure differs substantially from that of the over-stress model, the best-known rate-dependent inelastic constitutive model. The proposed constitutive model is a type of superposition model, which is premised on the additive decomposition of the inelastic strain rate into the plastic and creep strain rates. The plastic strain rate is formulated so as to become suppressed as the rate of deformation increases but is induced even at the infinite rate of deformation. This is the distinguishing features of this model from the existing superposition models. The present model can describe realistically the rate-dependent inelastic deformation for a wide range of strain rates. On the other hand, the over-stress model cannot predict appropriately the difference of mechanical response due to the rate of deformation, especially being inapplicable to the description of deformation at high rate of deformation as known from the unrealistic prediction of the infinite strength at an infinite rate of deformation. The proposed model is applied to various metals, and its adequacy is verified through comparisons with various test data under a wide variety of strain rates and temperatures..
199. K. Hashiguchi, S. Ozaki, Takashi Okayasu, Unconventional friction theory based on the subloading surface concept, International Journal of Solids and Structures, 10.1016/j.ijsolstr.2004.08.006, 42, 5-6, 1705-1727, 2005.03, [URL], A constitutive model for the description of friction phenomena is formulated by incorporating the concept of the subloading surface [Hashiguchi, K., 1978. Plastic constitutive equations of granular materials. In: Proc. US-Japan Seminar Continuum Mech. Stast. Appr. Mech. Granular Materials, Sendai, pp. 321-329; Hashiguchi, K., 1980. Constitutive equations of elastoplastic materials with elastic-plastic transition. J. Appl. Mech. (ASME) 47 (1980) 266-272; Hashiguchi, K., 1989. Subloading surface model in unconventional plasticity. Int. J. Solids Struct. 25 (1989) 917-945] falling within the framework of unconventional plasticity [Drucker, D.C., 1988. Conventional and unconventional plastic response and representation. Appl. Mech. Rev. (ASME) 41 (1988) 151-167], which excludes the premise that the interior of a yield surface is a purely elastic domain. It describes the nonlinear relationship between the normal and tangential tractions on a contact surface. Furthermore, it predicts the gradual progress of sliding displacement with an increase in traction, and thus a judgment regarding the fulfillment of the sliding condition is not necessary. This is in contrast to a conventional friction model with a sliding surface enclosing an elastic domain, in which such gradual progress cannot be described and the judgment is required. Thus, a rough numerical calculation with large loading steps even in the explicit numerical method is allowed in the present friction model. In addition, typical friction boundary value problems are analyzed by the finite element method incorporating the present friction model..
200. K. Hashiguchi, Takashi Okayasu, K. Saitoh, Rate-dependent inelastic constitutive equation
The extension of elastoplasticity, International Journal of Plasticity, 10.1016/j.ijplas.2004.04.001, 21, 3, 463-491, 2005.03, [URL], A rate-dependent inelastic constitutive equation is formulated by extending the elastoplastic constitutive equation so as to retain the latter's mathematical structure and thus reduce to the latter equation at an infinitesimal rate of deformation. That structure differs substantially from that of the over-stress model, the best-known rate-dependent inelastic constitutive model. The proposed constitutive model is a type of superposition model, which is premised on the additive decomposition of the inelastic strain rate into the plastic and creep strain rates. The plastic strain rate is formulated so as to become suppressed as the rate of deformation increases but is induced even at the infinite rate of deformation. This is the distinguishing features of this model from the existing superposition models. The present model can describe realistically the rate-dependent inelastic deformation for a wide range of strain rates. On the other hand, the over-stress model cannot predict appropriately the difference of mechanical response due to the rate of deformation, especially being inapplicable to the description of deformation at high rate of deformation as known from the unrealistic prediction of the infinite strength at an infinite rate of deformation. The proposed model is applied to various metals, and its adequacy is verified through comparisons with various test data under a wide variety of strain rates and temperatures..
201. K. Hashiguchi, S. Ozaki, Takashi Okayasu, Unconventional friction theory based on the subloading surface concept, International Journal of Solids and Structures, 10.1016/j.ijsolstr.2004.08.006, 42, 5-6, 1705-1727, 2005.03, [URL], A constitutive model for the description of friction phenomena is formulated by incorporating the concept of the subloading surface [Hashiguchi, K., 1978. Plastic constitutive equations of granular materials. In: Proc. US-Japan Seminar Continuum Mech. Stast. Appr. Mech. Granular Materials, Sendai, pp. 321-329; Hashiguchi, K., 1980. Constitutive equations of elastoplastic materials with elastic-plastic transition. J. Appl. Mech. (ASME) 47 (1980) 266-272; Hashiguchi, K., 1989. Subloading surface model in unconventional plasticity. Int. J. Solids Struct. 25 (1989) 917-945] falling within the framework of unconventional plasticity [Drucker, D.C., 1988. Conventional and unconventional plastic response and representation. Appl. Mech. Rev. (ASME) 41 (1988) 151-167], which excludes the premise that the interior of a yield surface is a purely elastic domain. It describes the nonlinear relationship between the normal and tangential tractions on a contact surface. Furthermore, it predicts the gradual progress of sliding displacement with an increase in traction, and thus a judgment regarding the fulfillment of the sliding condition is not necessary. This is in contrast to a conventional friction model with a sliding surface enclosing an elastic domain, in which such gradual progress cannot be described and the judgment is required. Thus, a rough numerical calculation with large loading steps even in the explicit numerical method is allowed in the present friction model. In addition, typical friction boundary value problems are analyzed by the finite element method incorporating the present friction model..
202. K. Hashiguchi, Takashi Okayasu, K. Saitoh, Rate-dependent inelastic constitutive equation
The extension of elastoplasticity, International Journal of Plasticity, 10.1016/j.ijplas.2004.04.001, 21, 3, 463-491, 2005.03, [URL], A rate-dependent inelastic constitutive equation is formulated by extending the elastoplastic constitutive equation so as to retain the latter's mathematical structure and thus reduce to the latter equation at an infinitesimal rate of deformation. That structure differs substantially from that of the over-stress model, the best-known rate-dependent inelastic constitutive model. The proposed constitutive model is a type of superposition model, which is premised on the additive decomposition of the inelastic strain rate into the plastic and creep strain rates. The plastic strain rate is formulated so as to become suppressed as the rate of deformation increases but is induced even at the infinite rate of deformation. This is the distinguishing features of this model from the existing superposition models. The present model can describe realistically the rate-dependent inelastic deformation for a wide range of strain rates. On the other hand, the over-stress model cannot predict appropriately the difference of mechanical response due to the rate of deformation, especially being inapplicable to the description of deformation at high rate of deformation as known from the unrealistic prediction of the infinite strength at an infinite rate of deformation. The proposed model is applied to various metals, and its adequacy is verified through comparisons with various test data under a wide variety of strain rates and temperatures..
203. K. Hashiguchi, S. Ozaki, Takashi Okayasu, Unconventional friction theory based on the subloading surface concept, International Journal of Solids and Structures, 10.1016/j.ijsolstr.2004.08.006, 42, 5-6, 1705-1727, 2005.03, [URL], A constitutive model for the description of friction phenomena is formulated by incorporating the concept of the subloading surface [Hashiguchi, K., 1978. Plastic constitutive equations of granular materials. In: Proc. US-Japan Seminar Continuum Mech. Stast. Appr. Mech. Granular Materials, Sendai, pp. 321-329; Hashiguchi, K., 1980. Constitutive equations of elastoplastic materials with elastic-plastic transition. J. Appl. Mech. (ASME) 47 (1980) 266-272; Hashiguchi, K., 1989. Subloading surface model in unconventional plasticity. Int. J. Solids Struct. 25 (1989) 917-945] falling within the framework of unconventional plasticity [Drucker, D.C., 1988. Conventional and unconventional plastic response and representation. Appl. Mech. Rev. (ASME) 41 (1988) 151-167], which excludes the premise that the interior of a yield surface is a purely elastic domain. It describes the nonlinear relationship between the normal and tangential tractions on a contact surface. Furthermore, it predicts the gradual progress of sliding displacement with an increase in traction, and thus a judgment regarding the fulfillment of the sliding condition is not necessary. This is in contrast to a conventional friction model with a sliding surface enclosing an elastic domain, in which such gradual progress cannot be described and the judgment is required. Thus, a rough numerical calculation with large loading steps even in the explicit numerical method is allowed in the present friction model. In addition, typical friction boundary value problems are analyzed by the finite element method incorporating the present friction model..
204. Ozaki, S., Hashiguchi, K., Okayasu, T., Chen, D.H., Finite Element Analysis of the Wheel Traveling Phenomenon by the Subfriction Surface Model, International Conference on Computational & Experimental Engineering and Sciences 2005, 2005.01.
205. Ozaki, S., Hashiguchi, K., Okayasu, T., Chen, D.H., Subfriction Surface Model", International Conference on Computational & Experimental Engineering and Sciences 2005, 1422-1427, 2005.01.
206. Ozaki, T., Hashiguchi, K., Okayasu, T., Elastoplastic finite element analysis of footing problem on soil ground by the subloading surface model, International Conference on Computational & Experimental Engineering and Sciences 2005, 1428-1433, 2005.01.
207. Okayasu, T., Takabayashi, R., Hashiguchi, K., Inoue, E.., Proposal of elasto-viscoplastic constitutive model based on subloading surface concept and its application to metal material, International Conference on Computational & Experimental Engineering and Sciences 2005, 1440-1445, 2005.01.
208. 尾崎伸吾,岡安崇史,橋口公一,陳玳, すべり摩擦現象を考慮した圧密試験の土-水連成有限要素解析, 応用力学論文集(土木学会), 8, 349-359, 2005.01.
209. 岡安崇史, PIV法(粒子画像流速測定法), 地盤工学会誌(土と基礎), 53(2), 31-32, 2005.01.
210. Hashiguchi, K., Ozaki, S. and Okayasu, T., Unconventional friction theory based on the subloading surface concept, Int. J. Solids Struct., 41, 1705-1727, 2005.01.
211. Okayasu T., Hashiguchi, K., Yajima, D., Ozaki, T., Ozaki, S., Finite element analysis on uplift problem of ground anchor, Dislocations, Dislocations, Plasticity and Metal Forming (Proc. Plasticity ’05: 11th Int. Symp. Plasticity and its Application), 289-290, 2005.01.
212. Ozaki, T., Okayasu T., Hashiguchi, K. , Yajima, D., Deformation behavior analysis in tunnel excavation by elastoplastic finite element method based on subloading surface model, Dislocations, Plasticity and Metal Forming (Proc. Plasticity ’05: 11th Int. Symp. Plasticity and its Application), 292-294, 2005.01.
213. Yoshimaru, T., Okayasu T., Hashiguchi, K., Sakajo, S., A basic research of the strength to the solidification soil on the soft ground, Dislocations, Plasticity and Metal Forming (Proc. Plasticity ’05: 12th Int. Symp. Plasticity and its Application), 304-306, 2005.01.
214. Hira, M., Hashiguchi, K., Okayasu, K., Elastoplastic constitutive equation of volcanic sandy soil “SHIRASU” based on the subloading surface model, Dislocations, Plasticity and Metal Forming (Proc. Plasticity ’05: 11th Int. Symp. Plasticity and its Application), 262-264, 2005.01.
215. Shingo Ozaki, Koichi Hashiguchi, Takashi Okayasu, Naoki Hotta, Finite element analyses of frictional contact problems by the subloading-friction model, Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 70, 7, 995-1002, 2004.07, The subloading-friction model is the unconventional elastoplastic friction model which allows the slip displacement due to the contact stress below the sliding surface. It is capable of describing the nonlinear relationship between the normal and the tangential stress on the contact surface and a gradual progress of relative tangential displacement with the increase of the contact stress. In this paper, the compression problem of rectangular block, the indentation problem of circular rigid roller and the cyclic friction problem for the elastic body under the plane strain condition are analyzed by the finite element program incorporating the subloading-friction model. It is revealed that the distribution of contact stress is predicted appropriately and the accumulation of relative displacement due to the cyclic loading of contact tangential traction below the sliding condition can be described. Besides, the computation time is shortened by the present finite element program compared with programs with the conventional friction model..
216. Shingo Ozaki, Koichi Hashiguchi, Takashi Okayasu, Naoki Hotta, Finite element analyses of frictional contact problems by the subloading-friction model, Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 70, 7, 995-1002, 2004.07, The subloading-friction model is the unconventional elastoplastic friction model which allows the slip displacement due to the contact stress below the sliding surface. It is capable of describing the nonlinear relationship between the normal and the tangential stress on the contact surface and a gradual progress of relative tangential displacement with the increase of the contact stress. In this paper, the compression problem of rectangular block, the indentation problem of circular rigid roller and the cyclic friction problem for the elastic body under the plane strain condition are analyzed by the finite element program incorporating the subloading-friction model. It is revealed that the distribution of contact stress is predicted appropriately and the accumulation of relative displacement due to the cyclic loading of contact tangential traction below the sliding condition can be described. Besides, the computation time is shortened by the present finite element program compared with programs with the conventional friction model..
217. Shingo Ozaki, Koichi Hashiguchi, Takashi Okayasu, Naoki Hotta, Finite element analyses of frictional contact problems by the subloading-friction model, Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 70, 7, 995-1002, 2004.07, The subloading-friction model is the unconventional elastoplastic friction model which allows the slip displacement due to the contact stress below the sliding surface. It is capable of describing the nonlinear relationship between the normal and the tangential stress on the contact surface and a gradual progress of relative tangential displacement with the increase of the contact stress. In this paper, the compression problem of rectangular block, the indentation problem of circular rigid roller and the cyclic friction problem for the elastic body under the plane strain condition are analyzed by the finite element program incorporating the subloading-friction model. It is revealed that the distribution of contact stress is predicted appropriately and the accumulation of relative displacement due to the cyclic loading of contact tangential traction below the sliding condition can be described. Besides, the computation time is shortened by the present finite element program compared with programs with the conventional friction model..
218. 瀬戸内秀規,橋口公一,鹿内健志,岡安崇史, 下負荷面モデルによる繰返し円形応力負荷を受ける砂の変形挙動の予測および接線応力速度の効果, 応用力学論文集(土木学会), 7, 625-634, 2004.01.
219. 岡安崇史,橋口公一,尾崎利行,矢嶋泰基,尾崎伸吾,木下和典, 繰返し荷重を受けるアンカー周辺地盤の変形挙動に関する弾塑性有限要素解析, 応用力学論文集(土木学会), 7, 713-721, 2004.01.
220. 尾崎利行,岡安崇史,橋口公一,矢嶋泰基, 下負荷面モデルを導入した有限要素法による降下床実験のシミュレーション, 応用力学論文集(土木学会), 7, 693-702, 2004.01.
221. 吉丸哲司,橋口公一,岡安崇史,阪上最一, 盛土施工に伴う過圧密地盤に関する基礎的研究, 応用力学論文集(土木学会), 7, 617-624, 2004.01.
222. 尾崎伸吾,橋口公一,岡安崇史, 下負荷面摩擦モデルを用いた地盤-杭間の相互作用の弾塑性有限要素解析, 応用力学論文集(土木学会), 7, 579-587, 2004.01.
223. 尾崎伸吾,橋口公一,岡安崇史,堀田直岐, 下負荷面摩擦モデルを用いた接触・摩擦問題の有限要素解析, 日本機械学会論文集A編, 70, 995-1002, 2004.01.
224. 岡安崇史,橋口公一,尾崎利行,矢嶋泰基,尾崎伸吾, サイロ内紛粒体層の流動現象に関する弾塑性有限要素解析, 農業機械学会誌, 66(4), 57-64, 2004.01.
225. Hashiguchi, K., Ozaki, S., Okayasu, T. and Zaigo, T., Proposal of a phenome-nological friction model incorporating the subloading surface concept, Terramechanics, 24,37-42., 2004.01.
226. 岡安崇史,橋口公一,尾崎伸吾,武部和之,川口史郎,上野正実,深見公一郎, PIVによる地盤変形挙動の計測と地盤内応力予測に関する研究, テラメカニックス, 24, 43-48, 2004.01.
227. 岡安崇史,橋口公一,尾崎利行,矢島泰基,尾崎伸吾, Trap-Door問題に関する弾塑性有限要素解析, テラメカニックス, 24, 49-54, 2004.01.
228. Hashiguchi, K., Okayasu, T. and Saitoh, K., Rate-dependent inelastic constitutive equation: The extension of elastoplasticity, Int. J. Plasticity, 20, 463-491, 2004.01.
229. Okayasu, T., Hashiguchi, K., Ozaki, T, Yajima, D., Ozaki, S., Finite element simulation on uplift problem of ground anchor, Proc. Int. Conf. Comput. Exper. Eng. Sci., 806-811, 2004.01.
230. Ozaki, T., Okayasu, T., Hashiguchi, K. Yajima, D., Elastoplastic finite element analysis of the trapdoor problem, Proc. Int. Conf. Comput. Exper. Eng. Sci., 812-817, 2004.01.
231. Yoshimaru, T., Hashiguchi, K., Okayasu T., Sakajo, S., Deformation analysis of cohesive soft grounds with solidified surface under fill construction, Proc. Int. Conf. Comput. Exper. Eng. Sci., 854-859, 2004.01.
232. Koichi Hashiguchi, Takashi Okayasu, Shingo Ozaki, Friction theory based on the subloading surface concept, Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 69, 2, 295-301, 2003.02, A constitutive model for the description of friction phenomenon is formulated by incorporating the subloading surface concept proposed for the formulation of the unconventional plastic constitutive equation. It describes the nonlinearity of the relationship between the normal and the tangential forces on the contact boundary. Further, it describes the smooth relation of the contact force and the sliding distance, i.e. the smooth elastic-plastic transition and the thus the judgment for the fulfillment of friction condition is not needed, which is required in the conventional friction theory. Thus, a rough numerical calculation with large loading steps is allowed in the present model..
233. Takashi Okayasu, Koichi Hashiguchi, Generalized rate-dependent inelastic constitutive equation (application to metals), Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A, 69, 2, 288-294, 2003.02, The rate-dependent inelastic constitutive equation was formulated by extending the subloading model such that the plastic strain rate is suppressed with the increase of strain rate and incorporating the creep strain rate in the previous article. It retains the mathematical structure of the subloading surface model and thus reduces to the model itself at infinitesimal strain rate. It belongs to the superposition model premising on the additive decomposition of the inelastic strain rate into the plastic and the creep strain rates. It is applied to metals, and its adequacy is verified comparing with various test data at a wide variety of strain rates and temperatures..
234. 深見公一郎,上野正実,橋口公一,岡安崇史, 砂地盤における剛性車輪下の土の変形(第2報), 農業機械学会誌, 65, 3, 100-106, 2003.01.
235. 深見公一郎,上野正実,橋口公一,岡安崇史, 砂地盤における剛性車輪下の土の変形(第1報), 農業機械学会誌, 65, 3, 93-99, 2003.01.
236. 橋口公一,岡安崇史,尾崎伸吾, 下負荷面の概念に基づく摩擦理論, 日本機械学会論文集A編, 69, 678, 295-301, 2003.01.
237. 岡安崇史,橋口公一, 一般化速度依存性非弾性構成式(金属への適用), 日本機械学会論文集A編, 69, 678, 288-294, 2003.01.
238. 岡安崇史,橋口公一,尾崎利行,竹添亮, アンカー引抜時の地盤の変形挙動に関する弾塑性有限要素解析, 応用力学論文集(土木学会), 6,541-550, 2003.01.
239. Hashiguchi, K., Okayasu, T., Ozaki, T., Extended friction theory based on the subloading surface model, Discolations, Proc. Plasticity ’03: 10th Int. Symp. Plasticity and its Application, 531-533, 2003.01.
240. Setouchi, H., Hashiguchi, K., Shikanai, T., Okayasu, T., Tangential stress-rate effect in soils subjected to cyclic circular stress path in the deviatoric stress plane, Proc. Int. Conf. Comput. Exper. Eng. Sci., 830-835, 2003.01.
241. Mizuki Hira, Koichi Hashiguchi, Takashi Okayasu, Koichi Miwa, Deformation behavior of "Shirasu" and its prediction by the subloading surface model, Soils and Foundations, 42, 5, 37-46, 2002.10, The description of the deformation behavior of Shirasu (volcanic sandy soil) by the elastoplastic constitutive equation is studied adopting a subloading surface model with rotational hardening. Also, test results for isotropic consolidation and triaxial compression with several lateral stresses under the drained and the undrained conditions for various initial void ratios are reported. Further, simulation by the constitutive equation is compared with the test results. High ability of the constitutive equation for the prediction of mechanical behavior of Shirasu is verified by the comparison..
242. 岡安崇史,尾崎伸吾,武田敏, 新しい土の変位計測法, 農業機械学会誌, 64, 2, 14-17, 2002.01.
243. Hashiguchi, K., Saitoh, K., Okayasu, T. and Tsutsumi, S., Evaluation of typical conventional and unconventional plasticity models for prediction of softening behavior of soils, Geotechnique, 52, 561-573, 2002.01.
244. Hira, M., Hashiguchi, K., Okayasu, T. and Miwa, K., Deformation behavior of Shirasu and its prediction by the subloading surface model, Soils and Foundations, 42, 5, 37-46, 2002.01.
245. Tsutsumi, S., Hashiguchi, K., Okayasu, T., Saitoh, K., Peculiar response of plastically compressive materials with associated and non-associated flow rule, Plasticity, Damage and Fracture at Macro, Micro and Nano Scales (Proc. Plasticity ’02: 9th Int. Symp. Plasticity and its Application, 84-86, 2002.01.
246. Tsutsumi, S., Hashiguchi, K., Sugimoto, M., Takezoe, R., Okayasu, T., Dependency of inelastic flow directions on stress rate directions, Plasticity, Plasticity, Damage and Fracture at Macro, Micro and Nano Scales (Proc. Plasticity ’02: 9th Int. Symp. Plasticity and its Application), 750-752, 2002.01.
247. K. Hashiguchi, K. Saitoh, Takashi Okayasu, S. Tsutsumi, Evaluation of typical conventional and unconventional plasticity models for prediction of softening behaviour of soils, Geotechnique, 10.1680/geot.2002.52.8.561, 52, 8, 561-578, 2002.01, [URL], Conventional elastoplasticity is based on the idealisation that the interior of the yield surface is a purely elastic domain. This idealisation would not lead to unrealistic prediction of hardening behaviour, but would cause unrealistic prediction of softening behaviour, which is observed typically in overconsolidated soils, whereas metals and normally consolidated soils exhibit hardening behaviour. By contrast, unconventional elastoplasticity that does not use this idealisation makes it possible to describe the plastic deformation due to the change of stress inside the yield surface exhibiting a smooth elastic-plastic transition, and is thus expected to describe softening behaviour more accurately. In this paper the capabilities of conventional and unconventional elastoplasticity for describing softening behaviour are examined, comparing the Drucker-Prager model as the conventional one and the subloading surface model as the unconventional one for predicting the deformation behaviour of overconsolidated soils. It is concluded that unconventional elastoplasticity has to be adopted for predicting softening behaviour..
248. Koichi Hashiguchi, Alexander Y. Protasov, Takashi Okayasu, Post-localization analysis by the subloading surface model with tangential stress rate effect, Materials Science Research International, 7, 4, 265-272, 2001.12, Various constitutive models have been applied to the analyses of localized deformation of solids. However, most of them fall within the framework of the conventional plasticity premising that the interior of yield surface is an elastic domain and obeys the plastic potential theory in which the plastic stretching is independent of the stress rate component tangential to the yield surface. Therefore, they predict a stiff elastic response until the stress reaches the yield state and further a stiff elastoplastic response after yielding. On the other hand, the subloading surface model falling within the unconventional plasticity would be only the model capable of describing pertinently the plastic deformation induced by the rate of stress within the yield surface in general loading process including the unloading, reloading and inverse loading. Further, the numerical calculation by this model is quite efficient disusing the special algorism, e.g. the mean normal method and the radial return method in order to make the stress lie just on the yield surface in the plastic loading process since it contains the controlling function to make the stress approach automatically the yield surface in the plastic loading process. Further, this model is recently extended so as to describe the tangential stress rate effect, i.e. the inelastic deformation induced by the stress rate component tangential to the subloading surface. In this article the post-localized deformation of metal due to the shear band formation is analyzed by the finite element method incorporating the subloading surface model with the tangential stress rate effect. Thus, the influence of the tangential stress rate effect on the shear band formation is discussed exhibiting several examples of the deformation patterns..
249. 岡安崇史・橋口公一・尾崎伸吾, 弾塑性学に関するインターネット教育の一提案, 地盤工学会誌(土と基礎), 49, 11, 4-6, 2001.01.
250. 橋口公一・齊藤公志郎・岡安崇史・堤成一郎, 古典塑性論および非古典塑性論の軟化挙動予測特性, 応用力学論文集(土木学会), 4, 357-366, 2001.01.
251. 岡安崇史・橋口公一・堤成一郎・尾崎伸吾・上野正実, 繰返し負荷を受ける平板下の地盤の弾塑性有限要素解析, 農業機械学会誌, 63, 3, 67-73, 2001.01.
252. Okayasu, T. and Hashiguchi, K., Time-dependent elastoplastic constitutive equation of soils and its application to FEM implementation, Lowland Tech. Int., 3, 2, 66-83, 2001.01.
253. Hashiguchi, K., Protasov, A. Y. and Okayasu, T., Post-localization analysis by the subloading surface model with tangential stress rate effect, Materials Sci. Res. Int., 7, 4, 265-272, 2001.01.
254. Tsutsumi S., Hashiguchi K., Okayasu T., Saitoh K. and Sugimoto M., Mechanical response of the subloading surface model with tangential stretching, J. App. Mech. (JSCE), 4, 375-382, 2001.01.
255. Fukami, K., Ueno, M., Hashiguchi, K., Okayasu, T., Effects of traveling speed of a wheel on the soil deformation, Proc. 6th Asia-Pacific Reg. Conf. Terrain Vechicle System, 99-106, 2001.01.
256. Fukami, K., Ueno, M., Hashiguchi, K., Okayasu, T., Changes in soil deformation by the frictional property of a wheel with repetition travel, Proc. 6th Asia-Pacific Reg. Conf. Terrain Vechicle Systems, 114-121, 2001.01.
257. Hashiguchi, K., Tsutsumi, S., Okayasu, T., Saitoh, K., Subloading surface model with tangential stress rate effect and its application to soils, Bifurcation and Localization Theory Geomech. (IWBL'99), 201-207, 2001.01.
258. 橋口公一,堤成一郎,岡安崇史,斎藤公志郎, 接線応力速度を考慮した地盤材料の弾塑性構成式によるせん断帯発生の理論的考察, 農業機械学会誌, 62, 4, 71-80, 2000.01.
259. 橋口公一,堤成一郎,岡安崇史,斎藤公志郎, 接線応力速度を考慮した弾塑性構成式の提案および地盤材料への適用, 農業機械学会誌, 62, 3, 68-75, 2000.01.
260. 橋口公一,岡安崇史,堤成一郎,上野正実, 拡張下負荷面モデルを導入した有限変形・土-水連成有限要素解析プログラムの開発, 農業機械学会誌, 62, 1, 11-19., 2000.01.
261. 井上英二,平井康丸,橋口公一,岡安崇史, 稲稈の周波数応答特性に関する理論的考察, 農業機械学会誌, 62, 2, 73-80, 2000.01.
262. Hashiguchi, K. and Okayasu, T., Time-dependent elastoplastic constitutive equation Based on subloading surface model and its application to soils, Soils and Foundations., 40, 3, 21-36, 2000.01.
263. Shikanai T., Hashiguchi K., Nohse Y., Ueno M., and Okayasu T., Precise measurement of soil deformation and fluctuation in drawbar pull for steel and rubber-coated rigid wheels, J. Terramech., 37, 12, 21-39, 2000.01.
264. Fukami, K., Ueno, M., Hashiguchi, K. , Okayasu, T., Fluctuation of the drawbar pull of a wheel due to the inhomogeneous soil deformation, Proc. Int. Conf. Agr. Eng., 42-49, 2000.01.
265. Fukami, K., Ueno, M., Hashiguchi, K., Okayasu, T., Analysis of soil deformation beneath a wheel in the repetition travel, Proc. CIGR2000, 1499-1503, 2000.01.
266. Hashiguchi K., Saitoh K., Okayasu T., Tsutsumi S., Comparison of Drucker-Prager’s and subloading surface models for prediction of soil deformation behavior, Proc. Int. Symp. Plasticity 2000 (Proc. Eighth Int. Symp. Plasticity and Its Current Applications), 297-299, 2000.01.
267. Hashiguchi, K., Tsutsumi, S., Okayasu, T., Saitoh, K., Shear band analysis in soils by elastoplastic constitutive equation with tangential stress rate effect, Proc. Int. Symp. Plasticity 2000 (Proc. Eighth Int. Symp. Plasticity and Its Current Applications, 300-302, 2000.01.
268. Okayasu, T., Hashiguchi, K., Tsutsumi, S., Deformation behavior of shallow foundation beneath footing subjected to cyclic load, Proc. Int. Symp. Plasticity 2000 (Proc. Eighth Int. Symp. Plasticity and Its Current Applications), 309-401, 2000.01.
269. T. Shikanai, K. Hashiguchi, Y. Nohse, M. Ueno, Takashi Okayasu, Precise measurement of soil deformation and fluctuation in drawbar pull for steel and rubber-coated rigid wheels, Journal of Terramechanics, 10.1016/S0022-4898(99)00011-7, 37, 1, 21-39, 2000.01, [URL], The travelling performance of rigid wheels on sand stratum is measured using two kinds of surface material, i.e. steel and steel coated with rubber. A new method for measuring the displacement of soil beneath the wheel has been developed using small polyester film markers. The trajectories of soil particles beneath the wheels are approximated by an exponential function and the fluctuations in the drawbar pull are represented by a sinusoidal function. The amplitude and basic wavelength of the fluctuation in the drawbar pull are discussed for both types of wheels..
270. Koichi Hashiguchi, Takashi Okayasu, Time-dependent elastoplastic constitutive equation based on the subloading surface model and its application to soils, Soils and Foundations, 10.3208/sandf.40.4_19, 40, 4, 19-36, 2000.01, [URL], Various constitutive models for the description of time-dependent deformation behavior have been proposed. However, it is first verified in this article that a pertinent model applicable to the description of deformation for a wide range of stress below and over the elastic limit, i.e. the yield stress, has not been found up to the present. It should be noted that a stress goes out over the yield surface at a high rate of deformation, only elastic deformation being induced. The subloading surface model does not premise that a stress exists on the yield surface even in the plastic loading process and thus describes the plastic deformation induced by the rate of stress within the yield surface, exhibiting the smooth elastic-plastic transition. In this article the subloading surface model is extended so as to describe the time-dependence for a wide range of deformation rates by allowing the stress to go out from the yield surface based on the physical interpretation that a plastic deformation due to the mutual slip between microstructures is suppressed for the deformation at a high rate causing the increase of viscous resistance acting between the microstructures. Further, based on this, a time-dependent elastoplastic constitutive equation of soils is formulated by incorporating the secondary-consolidation phenomenon, and its ability to predict deformation behavior of soils is verified by comparisons with test data on fundamental time-dependent behavior with various deformation rates, creep and stress relaxation under the undrained condition..
271. 上野正実,岡安崇史,橋口公一,鹿内健志,大嶺政朗, 砂地盤上の剛性車輪のけん引変動に関する力学的考察, 農業機械学会誌, 61, 4, 75-84, 1999.01.
272. 上野正実,大嶺政朗,鹿内健志, 橋口公一,岡安崇史, 砂地盤上における剛性車輪の走行性高精度予測モデル, 農業機械学会誌, 61, 2, 101-110, 1999.01.
273. Hashiguchi, K., Wu, X., Okayasu, T., Time-dependent constitutive equation of soil, Proc. Int. Symp. Plasticity '99 (Proc. 7th Int. Symp. Plasticity & its Current Appl., 569-572, 1999.01.
274. 橋口公一,岡安崇史,上野正実,鹿内健志, 画像処理による土の変位のオンライン計測に関する研究, 農業機械学会誌, 60, 5, 3-10, 1998.01.
275. 井上英二,金暎根,橋口公一,岡安崇史,鹿島潤, 稲稈の力学的特性に関する一考察, 農業機械学会誌, 60, 2, ,97-102, 1998.01.
276. Hashiguchi, K., Wu, X., Okayasu, T. and Tsutsumi, S.,, Time-dependent elastoplastic constitutive model, Metals and Materials, 4, 345-349, 1998.01.
277. Ueno, M., Oomine, M., Shikanai, T., Hashiguchi, K., Okayasu, T., Precise prediction of the traveling performance for a rigid wheel, Proc. 5th Asia-Pacific Reg. Conf. Terrain Vechicle Systems, 374-383, 1998.01.
278. Ueno, M., Fukami, K., Shikanai, T., Hashiguchi, K., Okayasu, T., Waveform analysis of drawbarpull of a rigid wheel by FFT, Proc. 5th Asia-Pacific Reg. Conf. Terrain Vechicle Systems, 384-392, 1998.01.
279. Koichi Hashiguchi, Xianan Wu, Takashi Okayasu, Seiichiro Tsutsumi, Time-dependent elastoplastic constitutive model, Metals and Materials International, 4, 3, 345-349, 1998, The subloading surface model does not premise that the stress exists on the yield surface and thus describes a plastic deformation even when the stress exists inside the yield surface. The measure describing the degree that the stress approaches the yield surface or goes out from the surface is involved in this model. It is extended so as to describe the time-dependent deformation behavior of materials by allowing the stress to go out from the yield surface and considering the fact that a plastic deformation requires time to occur, although an elastic deformation is induced momentarily. Further, based on it, the constitutive equation of soils is formulated by taking the secondary consolidation phenomenon into account..
280. Koichi Hashiguchi, Takashi Okayasu, Seiichiro Tsutsumi, The Extended Elastoplastic Constitutive Equation with Tangential Stress Rate Effect, Journal of the Faculty of Agriculture, Kyushu University, 42, 1-2, 225-235, 1997.12, The extension of the elastoplastic constitutive equation so as to describe the plastic stretching due to the stress rate component tangential to the yield or loading surface has been one of the most pressing problems in the elastoplasticity. To this aim, various models have been proposed in the past. However, a pertinent model applicable to a general loading process has not previously been proposed. In this article, the elastoplastic constitutive equation extended so as to describe a plastic stretching due to a stress rate component tangential to a yield or loading surface is formulated keeping a single and smooth yield surface. It would be a pertinent one which fulfills the mechanical requirements for elastoplastic constitutive equation and which is applicable to an arbitrary loading process. Based on this equation, a constitutive equation of metals with the isotropic-kinematic hardening is formulated..
281. 鹿内健志,上野正実,橋口公一,能勢行則,岡安崇史, 走行車輪下の土の変形の精密計測, 農業機械学会誌, 59, 2, 3-12, 1997.01.
282. Hashiguchi, K., Okayasu, T., Sakajo, S., On the general flow rule, On the general flow rule, Proc. 6th Int. Symp. Numer. Models Geomech., pp.87-92, 1997., 87-92, 1997.01.
283. Ueno, M., Shikanai, T., Okayasu, T., Hashiguchi, K., Nohse, Y., Gotoh, M., Uchiyama, K., Walking motion of the soil reaction on a whee, Proc. 4th Asia-Pacific Regional Conf. Terrain Vechicle Systems, 199-206, 1995.01.
284. Ueno, M., Shikanai, T., Okayasu, T., Hashiguchi, K., Nohse, Y., Gotoh, M, Uchiyama, K., Soil deformation beneath a rigid wheel, Proc. 4th Asia-Pacific Regional Conf. Terrain Vechicle Systems, 133-140, 1995.01.

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