Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Takashi OKAYASU Last modified date:2021.06.17

Associate Professor / Bioproduction Environmental Sciences / Department of Agro-environmental Sciences / Faculty of Agriculture


Presentations
1. Ko, K. M. M. , Hirai Y. , Yamakawa, T. , Inoue, E., Okayasu, T., Mitsuoka, M., Effects of unflooded periods and growth stage on nitrogen mineralization of green manure (hairy vetch) under flooded conditions, International Symposium on Agriculture, Food, Environmental and Life Science in Asia 2019, 2019.11.
2. Hamidah, A., Okayasu, T., Hoshino, Y., Inoue, E., Yasumaru, H., Mitsuoka, M., Nugroho, A.P., Sutiarso, L., Accuracy Evaluation of Low-cost Weight Measurement Sensor for Plants, International Symposium on Agriculture, Food, Environmental and Life Science in Asia 2019, 2020.11.
3. Okayasu T., Smart Agriculture Utilizing Affordable IoT Devices, International Symposium on Agriculture, Food, Environmental and Life Science in Asia 2019, 2019.11.
4. 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, 2019.12, 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%..
5. 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, 2019.12, 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..
6. 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, 2019.12, 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..
7. 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, 2019.12, 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..
8. 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, 2019.11, 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..
9. 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, 2019.11, 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..
10. Nayeen Al Amin, Takashi Okayasu, Masafumi Horimoto, Hideto Kurosaki Takehiko Hoshi, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, Development of Irrigation Management System Based on LPWAN-UECS for Distributed Open Fields, 2019年度農業情報学会年次大会, 2019.05.
11. Astriati Hamidah, Takashi Okayasu, Yu Hoshino, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, Andri Prima Nugroho and Lilik Sutiarso, Plant Weight Measurement Using Low Cost Load Cell and Its Accuracy Evaluation, 2019年度農業情報学会年次大会, 2019.05.
12. 内山美咲・岡安崇史・政井隆之・田中泰洋・前田衡・安武大輔・井上英二・平井康丸・光岡宗司, 深層学習で得られたイチゴ生育特徴量の利用に関する研究, 2019年度農業情報学会年次大会, 2019.05.
13. 長浜義典,野田龍一,野村浩一,安武大輔,岩尾忠重,北野雅治,井上英二,岡安崇史, RGB-D センサを用いた植物生育特徴量の計測とその精度評価, 2019年度農業情報学会年次大会, 2019.05.
14. Nayeen Al Amin, Takashi Okayasu, Masafumi Horimoto, Hideto Kurosaki Takehiko Hoshi, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, Development of Irrigation Management System Based on LPWAN-UECS for Distributed Open Fields, 2019年度農業情報学会年次大会, 2019.05.
15. Astriati Hamidah, Takashi Okayasu, Yu Hoshino, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, Andri Prima Nugroho and Lilik Sutiarso, Plant Weight Measurement Using Low Cost Load Cell and Its Accuracy Evaluation, 2019年度農業情報学会年次大会, 2019.05.
16. Akinori Ozaki, Panitan Kaewjantawee, Monton Anongponyoskul, Nguyen Van Thinh, Masaru Matsumoto, Masayoshi Harada, Kunihiko Hamagami, Takashi Okayasu, Heat storage induced by salinity stratification in tropical saline aquaculture ponds, 2019 ASABE Annual International Meeting, 2019.01, In saline aquaculture ponds in the tropics, intermittent rainfall during the rainy season can cause salinity stratification, and strong solar radiation can cause thermal stratification. The combination of these factors may result in thermohaline convection in the ponds. Thermohaline convection in a closed saline water body can in turn induce heat storage in these ponds. Heat storage in saline aquaculture ponds strongly influences the water environment and consequently affects the quality and yield of aquaculture products from these ponds. We investigated how heat storage in experimental saline aquaculture ponds was influenced by the variation in the weather and water properties during the rainy season. If the pond stratifies into three layers with a salinity gradient in the middle layer, heat storage can occur. The salinity gradient prevents heat from escaping from the lower layer by effectively insulating it from nighttime radiative cooling. When the salinity gradient is perturbed by rainfall, solar radiation, or wind, the heat stored in the pond can begin to dissipate. We explain how the stratification stability and the heat balance in the ponds account for the occurrence of heat storage in the ponds..
17. Akinori Ozaki, Panitan Kaewjantawee, Monton Anongponyoskul, Nguyen Van Thinh, Masaru Matsumoto, Masayoshi Harada, Kunihiko Hamagami, Takashi Okayasu, Heat storage induced by salinity stratification in tropical saline aquaculture ponds, 2019 ASABE Annual International Meeting, 2019.01, In saline aquaculture ponds in the tropics, intermittent rainfall during the rainy season can cause salinity stratification, and strong solar radiation can cause thermal stratification. The combination of these factors may result in thermohaline convection in the ponds. Thermohaline convection in a closed saline water body can in turn induce heat storage in these ponds. Heat storage in saline aquaculture ponds strongly influences the water environment and consequently affects the quality and yield of aquaculture products from these ponds. We investigated how heat storage in experimental saline aquaculture ponds was influenced by the variation in the weather and water properties during the rainy season. If the pond stratifies into three layers with a salinity gradient in the middle layer, heat storage can occur. The salinity gradient prevents heat from escaping from the lower layer by effectively insulating it from nighttime radiative cooling. When the salinity gradient is perturbed by rainfall, solar radiation, or wind, the heat stored in the pond can begin to dissipate. We explain how the stratification stability and the heat balance in the ponds account for the occurrence of heat storage in the ponds..
18. 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, 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..
19. 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, AFITA/WCCA2018, 2018.10.
20. SHINSOYOUNG, 井上英二, 光岡宗司, 岡安崇史, 平井康丸, 3-Dimensional Reconstruction of Traveling Terrain and Prediction of Rollover Risk of Agricultural Machinery, 農業環境工学関連学会2018年合同大会, 2018.09.
21. Takashi Okayasu, Masami Katayama, Takahisa Nakamura, Ippei Kijiya and Tatsuya Ishikawa, Development of a web-based data sharing and management platform to improve accuracy and reliability of elastoplastic constitutive model, Fourth International Conference on Railway Technology: Research, Development and Maintenance, 2018.09.
22. AminNayeen Al, OkayasuTakashi, InoueEiji , (Kyushu University), HiraiYasumaru (Kyushu University), MitsuokaMuneshi (Kyushu University), HoshiTakehiko (Kindai University), HorimotoMasafumi () Holly & Co. Ltd), Smart irrigation management system to enhance agriculture in Bangladesh using UECS and LPWAN, 第72回農業食料工学会九州支部例会, 2018.08.
23. Nayeen Al Amin, Takashi Okayasu, Masafumi Horimoto, Takehiko Hoshi, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, Investigation of communication networking protocol for UECS using IM920 and its validity, 2018年度農業情報学会年次大会, 2018.05.
24. Takashi Okayasu, Andri Prima Nugroho, Atsushige Sakai, Disaku Arita, Takashi Yoshinaga, Rin-Ichiro Taniguchi, Masafumi Horimoto, Eiji Inoue, Hirai Yasumaru, Mitsuoka Muneshi, Affordable field environmental monitoring and plant growth measurement system for smart agriculture, 11th International Conference on Sensing Technology, ICST 2017, 2018.02, Nowadays, various affordable sensors and devices have been developed and utilized in a wide area of sectors. Needless to say, agriculture sector is no exception. They have already been applied to improve agricultural production in terms of advancing the knowledge and techniques of farming, reducing production costs, and improving the quality of agricultural produce. This paper introduces the current situation and example of the affordable sensors and devices for field environment monitoring and plant growth measurement in smart agriculture..
25. Hideaki Uchiyama, Shunsuke Sakurai, Yoshiki Hashimoto, Atsutoshi Hanasaki, Daisaku Arita, Takashi Okayasu, Atsushi Shimada, Rin-Ichiro Taniguchi, Sensing technologies for advanced smart agricultural systems, 11th International Conference on Sensing Technology, ICST 2017, 2018.02, We introduce our sensing technologies to acquire agricultural information, such as image-based plant phenotyping, harvest quantity data, and localization information using a camera in a greenhouse. Commercial systems exist that support agriculture, but many unresolved issues remain regarding optimization of farming sustainability and productivity. Therefore, we intend to apply state-of-the-art information and communication technology (ICT) to tackle these agricultural issues and to investigate their limitations for developing advanced smart agricultural systems..
26. Hideaki Uchiyama, Shunsuke Sakurai, Masashi Mishima, Daisaku Arita, Takashi Okayasu, Atsushi Shimada, Rin-Ichiro Taniguchi, An Easy-to-Setup 3D Phenotyping Platform for KOMATSUNA Dataset, 16th IEEE International Conference on Computer Vision Workshops, ICCVW 2017, 2018.01, We present a 3D phenotyping platform that measures both plant growth and environmental information in small indoor environments for plant image datasets. Our objective is to construct a compact and complete platform by using commercial devices to allow any researcher to begin plant phenotyping in their laboratory. In addition, we introduce our annotation tool to manually but effectively create leaf labels in plant images on a pixel-by-pixel basis. Finally, we show our RGB-D and multiview datasets containing images in the early growth stages of the Komatsuna with leaf annotation..
27. Hideaki Uchiyama, Shunsuke Sakurai, Toshiki Hashimoto and Atsutoshi Hanasaki, Daisaku Arita, Takashi Okayasu, Atsushi Shimada and Rin-ichiro Taniguchi, Sensing Technologies for Advanced Smart Agricultural Systems, International Symposium on Agricultural, Food, Environmental and Life Sciences in Asia, 2017 (AFELiSA 2017), 2017.12.
28. Takashi Okayasu, Andri Prima Nugroho, Atsushige Sakai, Disaku Arita, Takashi Yoshinaga, Rin-ichiro Taniguchi, Masafumi Horimoto, Eiji Inoue, Yasumaru Hirai, and Muneshi Mitsuoka, Affordable Field Environmental Monitoring and Plant Growth Measurement System for Smart Agriculture, International Symposium on Agricultural, Food, Environmental and Life Sciences in Asia, 2017 (AFELiSA 2017), 2017.12.
29. Muhammad Naufal Rauf Ibrahim, Takashi Okayasu, Atsushi Yoshimura, Yoshiyuki Yamagata, Naruto Furuya, Eiji Inoue, Yasumasu Hirai, Muneshi Mitsuoka, Identification and Evaluation of Bacterial Leaf Blight on Rice Field Using Hyperspectral Imaging, International Symposium on Agricultural, Food, Environmental and Life Sciences in Asia, 2017 (AFELiSA 2017), 2017.11.
30. Takashi Okayasu, ICT Application in Agriculture with Affordable Sensors and Devices, 2nd International Conference on Tropical Agriculture, 2017.10.
31. SHIN SOYOUNG,光岡宗司,井上英二,岡安崇史,平井康丸, Terrain Reconstruction Using Stereo Vision Camera forTractor Rollover Estimation, 第76回農業食料工学会年次大会, 2017.09.
32. Takashi OKAYASU, IT: an enabling technology for small- and medium-scale farmers in Japan, Conference on Smart Agriculture for Sustainable, Inclusive Productivity, 2017.09.
33. Takashi OKAYASU, Measurement and Visualization of Agricultural Information by Using ICT, Forum “Math-for-Industry” 2016 –Agriculture as a metaphor for creativity in all human endeavor- in QUT, Brisbane, Australia. , 2016.11.
34. Soyoung SHIN, Eiji INOUE, Muneshi MITSUOKA, Takashi OKAYASU, Yasumaru HIRAI, Investigation of Tire Air Pressure of Tractor with Tire Pressure Monitoring System, 第70回農業食料工学会九州支部例会, 2016.09.
35. Andri Prima Nugroho, Takashi Okayasu, Eiji Inoue, Yasumaru Hirai, Muneshi Mitsuoka, Lilik Sutiarso, Smart Agriculture Framework and Its Implementation to Open-Field Tropical Horticulture Production, 第70回農業食料工学会九州支部例会, 2016.09.
36. 岡安 崇史, ICT application for typical small- and medium-scale farmers in Japan Agriculture, Conference on State-of-the-Art Technology to Drive Agriculture Productivity in the Next Quarter of the Century, 2016.06, 中小規模農業経営におけるICT応用に関する課題やその具体的導入方法について解説した。.
37. 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, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05.
38. 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, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05, We have proposed an automatic leaf motion analysis based on Infrared (IR) photography. The proposed system allows continuous, high-resolution time-lapse imaging, independent of the present of visible light, and based on open source platform. The utilization of microcomputer as a capturing unit might increase the simplicity and flexibility. The IR camera positioned above the plant as top view projection to capture the foliage images. As the motion tracking, the Optical Flow method was adopted, implementing the Lucas-Kanade technique with Shi-Tomasi corner detection. Optical flow is one of the motion detection methods to analyze the motion between two consecutive images by differentiating the constraint. Displacement distance and direction angle were used as a parameter for evaluation with regards to circadian rhythm. As the result, the proposed automatic leaf motion analysis could perform a continuous IR time-lapse photography and analyze the lateral 2D motion using the Optical Flow method. The highest probability of displacement distance observed at 6px (48%) and the direction angle was at 180° (39.2%). According to the visual appearance of time series data, the motion displacement seems to have a regular pattern resembles the circadian rhythm with regards to environmental changes although the noise also appears. To verify the relation between displacement distance, motion angle and circadian rhythm, analysis of phase and amplitude of data using a Fast Fourier Transform Nonlinear Least Squares (FFT-NLS) method will be in our future works..
39. 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, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05.
40. Momanyi J. Simanto, M. J., Mitsuoka, M., Inoue, E., Okayasu, T., Hirai, Y., Investigation of the mechanical threshing characteristics of sorghum, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05.
41. Hashimoto, Y., Arita, D., Shimda, A., Okayasu, T., Uchiyama, H., Taniguchi, R., Farmer position estimation in a tomato plant green house with smart devices, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05.
42. 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, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05.
43. 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, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05.
44. 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, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05.
45. Mitsuoka, M., Takata, K., Inoue, E., Okayasu, T., Hirai, Y., Correlation anomaly detection by using time series data of agricultural machinery, 8th International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) , 2016.05.
46. Okayasu, T., Trials on ICT application for typical small and medium scale farmers in Japan agriculture, AWSSS2016, 2016.03.
47. OKAYASU, T., Agricultural informatics in Japan -For typical small and medium scale farmers-, THE 11TH INTERNATIONAL WORKSHOP ON NONDESTRUCTIVE QUALITY EVALUATION OF AGRICULTURAL, LIVESTOCK AND FISHERY PRODUCTS, 2015.11.
48. Okayasu, T., Tsuchiya, K., Fukami, K., Inoue, E., Hirai, Y., Mitsuoka, M., Soil tillage simulation using FEM-DEM quasi-coupling method, ISTVS 13th European Conference, 2015.10.
49. Takashi OKAYASU, Takahisa NAKAMURA, Katsumi MURAMOTO, Yoshitsugu MOMOYA, Cyclic elastoplastic deformation analysis on Ballasted railway track, The Second Workshop of Ballasted Track between Japan & the UK Cedar Suite, 2014.10.
50. Daisaku Arita, Takashi Okayasu, Andri Prima Nugroho, Takashi Yoshinaga, Nobushige Doi, Atsushi Shimada, Rin-ichiro Taniguchi, Agricultural information sensing and visualization for farmer-consumer communication, Joint Workshop on Machine Perception and Robotics, 2014.10.
51. Takashi Okayasu, Takahisa Nakamurab, Katsumi Muramoto, Yoshitsugu Momoya, Elastoplastic deformation behavior for ballast under monotonic and cyclic loading conditions, International Conference on International Society for Terrain-Vehicle Systems, 2014.09.
52. 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, International Symposium on Innovation Technology for Natural Resource Exploitation Toward Sustainable Environment, 2014.06.
53. 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, International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2014, 2014.05.
54. 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, International Symposium on Machinery and Mechatronics for Agriculture and Biosystems Engineering (ISMAB) 2014, 2014.05.
55. Daisaku Arita, Takashi Okayasu, Andri Prima Nuguroho, Takashi Yoshinaga, Agri-sensing for farmer-consumer communication, Asian Workshop on Smart Sensor Systems, 2014.03.
56. 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, 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..
57. Takashi Okayasu, Utilization of two SNSs in Japan agriculture, 2013 International Symposium on ICT Convergence in the Food and Agriculture, 2013.12.
58. Takashi Okayasu, Atsushige Sakai, Disaku Arita, Takashi Yoshinaga, Rin-ichiro Taniguchi, Eiji Inoue, Yasumaru Hirai, and Muneshi Mitsuoka, Development of Plant Growth Feature Measurement System Using Affordable Devices, International Symposium on Agricultural, Food, Environmental and Life Sciences in Asia, 2017 (AFELiSA 2017), 2013.11.
59. Takashi Okayasu, What is informatization agriculture?, International Symposium on Agricultural, Food, Environmental and Life Sciences in Asia, 2013 (AFELiSA 2013), 2013.11.
60. Takashi OKAYASU, Katsumi MURAMOTO, Takahisa NAKAMURA, Elastoplastic deformation analysis on ballasted track under repeated loading condition, Workshop on Ballasted Track Maintenance between Japan and the United Kingdom, 2013.11.
61. T. Fukuda, Takashi Okayasu, K. Tsuchiya, Eiji Inoue, Hirai Yasumaru, Mitsuoka Muneshi, H. Terao, Modeling and prediction of the mechanical interaction between soil and tillage tool by DEM, 11th International Conference on Analysis of Discontinuous Deformation, ICADD 2013, 2013.10, 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). Traction 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..
62. T. Fukuda, Takashi Okayasu, K. Tsuchiya, Eiji Inoue, Hirai Yasumaru, Mitsuoka Muneshi, H. Terao, Modeling and prediction of the mechanical interaction between soil and tillage tool by DEM, 11th International Conference on Analysis of Discontinuous Deformation, ICADD 2013, 2013.10, 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). Traction 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..
63. Takashi Okayasu, Andri Prima Nugroho, Daisaku Arita, Akinori Ozaki, Muneshi Mitsuoka, Teruaki Nanseki, Eiji Inoue, Yasumaru Hirai, Environmental Change Point Analysis and Its Application to Agriculture,Proceedings of International conference on Instrumentation, Control, Information Technology and System Integration, 2013.09.
64. Takashi OKAYASU, Informatization Agriculture in Japan, The International Symposium on Agricultural and Biosystem Engineering (ISABE) 2013, 2013.08, Agriculture is dependent on climate, weather, soil conditions, and crop types. Therefore, farmers have tried to develop and improve their own cultivation techniques and senses during the long-term experiences so as to fit the peripheral field environment. Information Communication Technology (ICT) is currently applied in several fields of agriculture to improve the agricultural productivity and cultivation skills. There are many kinds of ICT-agriculture applications that already used for supporting the agricultural production such as environmental monitoring, precision agriculture including spatial data collection, precision irrigation and supplying data to farmers, facility automation including greenhouse control and animal-feeding facility (Wang, 2006).
On the other hand, authors have tried to develop the informatization agricultural supporting system called “Agri-eye” to optimize the agricultural production system (Okayasu et al., 2010). This system is composed of field environmental monitoring and acquisition, crop growth diagnosis and quality evaluation, work history recording, data analysis and visualization, and communication tools, and so on. The field environmental monitoring devices above 50 have been installed in the fields above 10 mainly in the Fukuoka and the Oita prefectures. The work recording system has been also distributed over the Internet and can be utilized through the web browsers on personal computers, mobile phones, and smartphones. The validity of the systems has been verified by the feasibility studies up to present.
In this article, several application examples of the informatization agriculture in Japan will be introduced here..
65. Takahisa FUKUDA, Takashi OKAYASU, Keita TSUCHIYA, Eiji INOUE, Yasumaru HIRAI, Muneshi MITSUOKA, Modeling and Prediction of the Mechanical Interaction between Soil and Tillage Tool by DEM, 11th Int. Conf. Anal. Discontinuous Deformation, 2013.08.
66. Andri Prima NUGROHO, Takashi OKAYASU, Muneshi MITSUOKA, Eiji INOUE, Lilik SUTIARSO, Yasumaru HIRAI, Development of Web-based Change Point Analysis for Field Environmental Information in Agriculture, International Symposium on Agricultural and Biosystem Engineering 2013, 2013.08.
67. Takashi Okayasu, Soil-tool interaction analysis using fem & dem coupling method, International Seminar Program in Chonbuk National University, 2013.05.
68. Miyoshi, Y., Hidaka, K., Okayasu, T., Hirano, O., Yasutake, D., Kitano, M., Approach to Local Enviroment Control for Stable Production of Stawberry, IFAC2013 Bio Robotics Conf., 2013.03.
69. Andri, N.P., Okayasu, T., Inoue, E., Hirai, Y. and Mitsuoka, M., Development of Actuation Framework for Agricultural Informatization Supporting System, IFAC2013 Bio Robotics Conf., 2013.03.
70. 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, 2013 52nd Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2013, 2013.01, 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..
71. 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, 2013 52nd Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2013, 2013.01, 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..
72. Ozaki, A., Okayasu, T., Rahman, M.A., Choudhury, D.K., Ogata, K., Miyajima, I., Ahmed, A., Ohsugi, T., Inoue, E., Potential of Informatization Agriculture in Bangladesh-Installation and Utilization of Field Monitoring System in Agriculture-, ICEAB2012, 2012.11.
73. Okayasu, T., Utilization of Field Monitoring Information to Agriculture - Potential of Informatization Agriculture in Bangladesh, ICEAB2012, 2012.11.
74. Okayasu, T., Mitsuoka, M., Andri, P.N., Yoshida, H., Nanseki, T. and Inoue, E, Change Point Analysis for Environmental Information in Agriculture, AFITA/WCCA2012, 2012.09.
75. Andri, P.N., Okayasu, T., Fushihara, H., Mitsuoka, M. and Inoue, E., Development of Intelligent Control System for Greenhouse, AFITA/WCCA2012, 2012.09.
76. Andri P,N., Okayasu, T., Mitsuoka, M., Inoue, E., Development of field monitoring and intelligent actuating system in agriculture, 農業機械学会九州支部第66回九州支部例会, 2012.08.
77. 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, 2012.07.
78. Okayasu, T., Morishita, K., Terao, H., Muneshi, M., Inoue, E., Fukami, K., Modeling and prediction of soil cutting behavior by a plow, CIGR-AgEng2012, 2012.07.
79. 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, 2012.07, 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..
80. 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, 6th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), 2012.06.
81. Okayasu, T., Andri, P.,N., Fushihara, Hirano, O., Yoshida, H., Inoue, E., Development of intelligent irrigation system for greenhouse, 6th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), 2012.06.
82. Okayasu, T. Mitsuoka, M., Andri P.N., Inoue, E., Application of Change Point Analysis for Long-term Environmental Monitoring Data, International Workshop on ICT in Geo-Engineering, 2012.05.
83. Soetiarso, L. Goenadi, S., Andri P.N., Okayasu, T., Monitoring of Hydraulic Gradient in Agricultural Land-use using Grid Wireless Sensor Network, International Workshop on ICT in Geo-Engineering, 2012.05.
84. 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, 2011.11, 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..
85. Okayasu, T., Yoshida, H., Miyazaki, T., Nanseki, T., Mitsuoka, M., Inoue, E., Feasibility Study on Field Monitoring and Work Recording System in Agriculture, ASAE2011, 2011.08.
86. Miyazaki, T., Okayasu, T., Inoue, E., Prediction of compaction behavior of heavy clayey soil beneath an off-road vehicle, ASAE2011, 2011.08.
87. 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, 2011.08, 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..
88. 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, 2011.08, 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..
89. Okayasu, T., Kamitsuji, N., Murakami, T., Miyazaki, T., Mitsuoka, M., Inoue, E., Fukami, K., Soil Compaction Analysis on Structured Cohesive Soft Ground, 9th Asia-Pacific Conference of the ISTVS, 2010.09.
90. Okayasu,T., Yamabe, N., Marui, A., Miyazaki, T., Mitsuoka, M., Inoue, E., Development of Field Monitoring and Work Recording System in Agriculture, ISMAB2010, 2010.04.
91. Miyazaki, T., Okayasu, T., Inoue, E., Tractor Running Tests at Isahaya Bay Reclamation, ISMAB2010, 2010.04.
92. Ashik, R.M., Mitsuoka, M., Takeoka, S., Inoue, E., Fukushima, T., Okayasu T., Dynamic Model of Half-Tracked Tractor Considering the Nonlinear Voigt Model, ISMAB2010, 2010.04.
93. 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, ISMAB2010, 2010.04.
94. Ueka, Y., Matsui, M., Inoue, E., Mori, K., Okayasu, T., Fluid Analysis of Cleaning Wind in Combine Harvester, ISMAB2010, 2010.04.
95. 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, ISMAB2010, 2010.04.
96. Mitsuoka, M., Tsuzimoto, T., Ashik, R.M., Inoue , E., Fukushima, T., Okayasu, T., Three Dimension Model of Vibration Characteristics of the Half-tracked Tractor, ISMAB2010, 2010.04.
97. Okayasu, T., Yamabe,N. Mrui, A. Mitsuoka, M., Inoue, E., Development of simple field monitoring system for agricultural production and management, IWABE2009, 2009.12.
98. Okayasu, T., Miyazaki, T., Kamitsuji, N., Mitsuoka, M., Inoue, E., Fukami, K., Numerical Soil Compaction Analysis on Structured Soft Ground, ISTRO2009, 2009.06.
99. 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, 2009.06.
100. Muneshi MITSUOKA, Yasutaka OKUDA, Kazuki MATSUMOTO, Takashi FUKUSHIMA, Takashi OKAYASU, Eiji INOUE, INVESTIGATION OF NONLINEAR VIBRATION CHARACTERISTICS OF THE HALF TRACKED TRACTOR, 4th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), 2008.05.
101. Eiji INOUE, Muneshi MITSUOKA, Norio OKURA, Takashi FUKUSHIMA, Takashi OKAYASU, INVESTIGATION OF NONLINEAR VIBRATION CHARACTERISTICS OF AGRICULTURAL RUBBER CRAWLER VEHICLES, 4th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), 2008.05.
102. 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, 4th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), 2008.05.
103. 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, 4th Int. Symp. Mach. Mech. Agr. Biosys. Engng. (ISMAB), 2008.05.
104. Muneshi Mitsuoka, Eiji Inoue, Takashi Fukushima, Takashi Okayasu, INVESTIGATION OF THE VIBRATION CHARACTERISTIC OF THE HALF TRACKED TRACTOR, Int. WS Agri. Biosy. Engng., 2007.12.
105. 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., 2007.12.
106. Muneshi Mitsuoka, Eiji INOUE*, Takashi Fukushima, Takashi Okayasu, Noiro Okura, INVESTIGATION OF VIBRATION CHARACTERISTICS OF AGRICULTURAL RUBBER CRAWLER VEHICLES, Int. S. Agr. Struct. Agr. Engng. 2007, 2007.12.
107. 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, 2007.12.
108. 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, 2005.12.
109. 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, 2005.12.
110. Okayasu T., Hashiguchi, K., Yajima, D., Ozaki, T and Ozaki, S., Finite element analysis on uplift problem of ground anchor, Plasticity ’05: 11th Int. Symp. Plasticity and its Application, 2005.01.
111. Hira, M., Hashiguchi, K. and Okayasu, K., Elastoplastic constitutive equation of volcanic sandy soil “SHIRASU” based on the subloading surface model, Plasticity ’05: 11th Int. Symp. Plasticity and its Application, 2005.01.
112. Ozaki, T., Okayasu T., Hashiguchi, K. and Yajima, D., Deformation behavior analysis in tunnel excavation by elastoplastic finite element method based on subloading surface model, Plasticity ’05: 11th Int. Symp. Plasticity and its Application, 2005.01.
113. Yoshimaru, T., Okayasu T., Hashiguchi, K. and Sakajo, S., A basic research of the strength to the solidification soil on the soft ground, Plasticity ’05: 11th Int. Symp. Plasticity and its Application, 2005.01.
114. Yoshimaru, T., Hashiguchi, K. Okayasu, T. and Sakajo, S., Deformation Analysis of Cohesive Soft Ground with Solidified Surface under Fill Construction, International Conference on Computational & Experimental Engineering and Sciences 2004, 2004.09.
115. Okayasu, T., Hashiguchi, K.., Ozaki, T., Yajima, D. and Ozaki, S., Finite Element Simulation on Uplift Problem of Ground Anchor, International Conference on Computational & Experimental Engineering and Sciences 2004, 2004.09.
116. Ozaki,T., Okayasu T., Hashiguchi K. and Yajima D., Elastoplastic Finite Element Analysis of the Trapdoor Problem, International Conference on Computational & Experimental Engineering and Sciences 2004, 2004.09.
117. Setouchi, H. Hashiguchi, K., Okayashu, T. and Shikanai, T., Tangential Stress-rate Effect in Soils Subjected to Cyclic Circular Stress Path in the Deviatoric Stress Plane, International Conference on Computational & Experimental Engineering and Sciences 2004, 2004.09.
118. HASHIGUCHI, K., KHOJASTEHPOUR, M., OKAYASU, T. and OZAKI, S., Symmetric Bifurcation Analysis by the Subloading Surface Model with Tangential Stretching, 第62回農業機械学会年次大会, 2003.04.
119. HASHIGUCHI, K. KHOJASTEHPOUR, M., OKAYASU, T. and OZAKI S.:, Elastoplastic Finite Element Analysis of Soil Beneath a Rigid Wheel, 第61回農業機械学会年次大会, 2002.09.