|野上 大史（のがみ ひろふみ）||データ更新日：2019.06.23|
|1.||Hirofumi Nogami, Wataru Iwasaki, Nobutomo Morita, Ryo Takigawa, Relationship between AC/DC Ratio and Light-blocking Structure
for Reflective Photoplethysmographic Sensor, Sensors and Materials, 30, 12, 3021-3028, 2018.12, Photoplethysmographic (PPG) sensors are suitable for wearable devices, and they can
provide a wide range of information such as stress level (calculated from the heart rate
interval), respiration rate, heart rate, and blood vessel stiffness. Of particular importance is that
reflective PPG sensors can be easily attached anywhere on the body with low wearer constraint.
However, PPG sensors are susceptible to body motion artifacts. The output signal of PPG
sensors is composed of alternating current (AC), originating from the heart cycle, and direct
current (DC), originating from veins and stationary tissue. Motion artifacts affect DC signals,
making it difficult to detect AC signals. Thus, it is important to reduce DC signals and increase
the AC/DC ratio. In this study, we investigated the effect of a light-blocking structure on the
AC/DC ratio. In addition, the AC/DC ratio was estimated when the gap between the light
source (LED) and the photodetector was small (3.2 mm) and large (8.0 mm). In this experiment,
the measurement part was a fingertip, and the AC/DC ratio was estimated when AC had the
highest output with the force from step-by-step contact. As a result, the AC/DC ratio of the
light-blocking structure was 2.4%, and the AC/DC of the non-light-blocking type was 0.9%.
Also, the AC/DC of the small-gap PPG sensor was 2.4%, and the AC/DC of the large-gap sensor
was 7.5%. Thus, the light-blocking structure was effective in increasing the AC/DC ratio, and a
larger distance between the LED and photodetector was useful..
|2.||Nogami Hirofumi, Shozo Arai, Hironao Okada, Lan Zhan, Toshihiro Itoh, Minimized Bolus-Type Wireless Sensor Node with a Built-In Three-Axis Acceleration Meter for Monitoring a Cow’s Rumen Conditions, Sensors, 10.3390/s17040687, 17, 4, 687, 2017.03.|
|3.||Hirofumi Nogami, Hironao Okada, Toru Miyamoto, Ryutaro Maeda, Toshihiro Itoh, Wearable wireless temperature sensor nodes appressed to base of a calf's tail, Sensors and Materials, 26, 8, 539-545, 2014.01, Respiratory diseases in calves are the primary cause of infantile death since calves have low resistance to viruses or bacteria and are vulnerable to respiratory diseases such as pneumonia. An effective method used successfully for the early detection of respiratory diseases is to measure the rectal temperature of a calf using a thermometer. However, this method can only be conducted infrequently since it requires significant time and effort from farmers during group feeding. In order to minimize the time and effort required, we developed wearable wireless sensor nodes to automatically measure the body temperature of a calf. In our previous study, we succeeded in measuring the body temperature via wireless sensor nodes attached to a calf's tail, and correlated it with the rectal temperature. However, the wireless sensor nodes developed in that study would often indicate a lower temperature. The cause was due to a gap, which was attributed to the 7 mm thickness of the sensor nodes, between the measurement location on the calf and the temperature sensor. In order to address these problems, we designed new sensor nodes that were best suited to measure the temperature of the base of a calf's tail. As a result, we could accomplish measurement stability for the temperature sensor..|
|4.||Hirofumi Nogami, Hironao Okada, Seiichi Takamatsu, Takeshi Kobayashi, Ryutaro Maeda, Toshihiro Itoh, Unique activity-meter with piezoelectric poly(vinylidene difluoride) films and self weight of the sensor nodes, Japanese journal of applied physics, 10.7567/JJAP.52.09KD15, 52, 9 PART2, 2013.09, [URL], We have developed piezoelectric switches for application in ultra low-power wireless sensor nodes to monitor the health condition of chickens. Using Pb(Zr0.52,Ti0.48)O3 (PZT) thin films, we have developed S-shaped PZT cantilevers with proof masses. Since the resonant frequency of PZT devices is approximately 24 Hz, we have utilized their superharmonic resonance to detect chicken movements with frequencies as low as 5- 15 Hz. By attaching sensor nodes to chickens, we successfully measured the activity of chickens. However, the PZT devices of other sensor nodes broke down. S-shaped PZT devices are adequate for low vibrations, but are beset by the structural problems of fragmentation upon impact. To address these problems, we examine a method of utilizing poly(vinylidene difluoride) (PVDF) films, which are tough and generate high piezoelectric output voltages under a large stress, as piezoelectric switches. We suggest that the self-weight of sensor nodes be used as the mass of the cantilevers of the PVDF films. One end of a PVDF film is fixed to the case of a sensor node, and the other end is attached to the sensor node. Since PVDF films are subjected to force generated by the self-weight of sensor nodes, high output voltages are expected. A result of measuring output voltages, we confirm the output voltages to be approximately the same as those of PZT devices below 15Hz at 0.5 m/s2 vibration, which is close to chicken movements. Thus, we consider that we have successfully fabricated a tough wireless sensor node for chickens, utilizing the features of PVDF films..|
|5.||Hirofumi Nogami, T. Kobayashi, H. Okada, N. Makimoto, R. Maeda, T. Itoh, Piezoelectric MEMS switch to activate event-driven wireless sensor nodes, Smart Materials and Structures, 10.1088/0964-1726/22/9/095001, 22, 9, 2013.09, [URL], We have developed piezoelectric microelectromechanical systems (MEMS) switches and applied them to ultra-low power wireless sensor nodes, to monitor the health condition of chickens. The piezoelectric switches have 'S'-shaped piezoelectric cantilevers with a proof mass. Since the resonant frequency of the piezoelectric switches is around 24 Hz, we have utilized their superharmonic resonance to detect chicken movements as low as 5-15 Hz. When the vibration frequency is 4, 6 and 12 Hz, the piezoelectric switches vibrate at 0.5 m s -2 and generate 3-5 mV output voltages with superharmonic resonance. In order to detect such small piezoelectric output voltages, we employ comparator circuits that can be driven at low voltages, which can set the threshold voltage (Vth) from 1 to 31 mV with a 1 mV increment. When we set Vth at 4 mV, the output voltages of the piezoelectric MEMS switches vibrate below 15 Hz with amplitudes above 0.3 m s-2 and turn on the comparator circuits. Similarly, by setting Vth at 5 mV, the output voltages turn on the comparator circuits with vibrations above 0.4 m s-2. Furthermore, setting Vth at 10 mV causes vibrations above 0.5 m s-2 that turn on the comparator circuits. These results suggest that we can select small or fast chicken movements to utilize piezoelectric MEMS switches with comparator circuits..|
|6.||Hirofumi Nogami, Hironao Okada, Toru Miyamoto, Ryutaro Maeda, Toshihiro Itoh, Wearable and compact wireless sensor nodes for measuring the temperature of the base of a calf's tail, Sensors and Materials, 25, 9, 577-582, 2013.08, Calves have low resistance to viruses or bacteria and are predisposed to respiratory diseases such as pneumonia. Respiratory disease is the number-one cause of death in calves. An effective method for the early detection of respiratory diseases is to measure the rectal temperature with a thermometer. However, this cannot be frequently conducted because it requires too much time and effort of the farmers. As a method requiring minimal time and effort, we have developed wireless sensor nodes to automatically measure the body surface temperature of a calf. The sensor nodes are designed to be compact by using a 3-axis accelerometer with a temperature-sensing function and a chip antenna, which can measure any body surface of a calf. The fabricated sensor nodes, which can measure both temperature and acceleration, are 18×18×7 mm 3 and weigh 6.5 g including batteries. Their primary advantages are light weight and small size. Thus, we can easily attach the sensor nodes to the base of the calf's tail, which is one of the slimmest parts, and successfully measure the body surface temperature..|
|7.||Hirofumi Nogami, Takeshi Kobayashi, Hironao Okada, Takashi Masuda, Ryutaro Maeda, Toshihiro Itoh, Impact of reflow on the output characteristics of piezoelectric microelectromechanical system devices, Japanese journal of applied physics, 10.1143/JJAP.51.09LD11, 51, 9 PART 2, 2012.09, [URL], An animal health monitoring system and a wireless sensor node aimed at preventing the spread of animal-transmitted diseases and improving pastoral efficiency which are especially suitable for chickens, were developed. The sensor node uses a piezoelectric microelectromechanical system (MEMS) device and an event-driven system that is activated by the movements of a chicken. The piezoelectric MEMS device has two functions: a) it measures the activity of a chicken and b) switches the micro-control unit (MCU) of the wireless sensor node from the sleep mode. The piezoelectric MEMS device is required to produce high output voltages when the chicken moves. However, after the piezoelectric MEMS device was reflowed to the wireless sensor node, the output voltages of the piezoelectric MEMS device decreased. The main reason for this might be the loss of residual polarization, which is affected by the thermal load during the reflow process. After the reflow process, we were not able to apply a voltage to the piezoelectric MEMS device; thus, the piezoelectric output voltage was not increased by repoling the piezoelectric MEMS device. To address the thermal load of the reflow process, we established a thermal poling treatment, which achieves a higher temperature than the reflow process. We found that on increasing the thermal poling temperature, the piezoelectric output voltages did not decreased low significantly. Thus, we considered that a thermal poling temperature higher than that of the reflow process prevents the piezoelectric output voltage reduction caused by the thermal load..|
|8.||Hirofumi Nogami, W. Iwasaki, T. Abe, Y. Kimura, A. Onoe, E. Higurashi, S. Takeuchi, Makiko Nakahara, Masutaka Furue, Renshi Sawada, Use of a simple arm-raising test with a portable laser Doppler blood flow meter to detect dehydration, Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 10.1243/09544119JEIM727, 225, 4, 411-419, 2011.04, [URL], Using micro electromechanical systems (MEMS) technologies, the authors have developed the world's smallest, lightest, and least power-consuming laser Doppler blood flow meter. Unlike commercial fibre-type blood flow instruments, the new blood flow meter is invulnerable to any movements of the person wearing it and has a wireless transmitter. Utilizing the characteristics of the blood flow meter, the authors attempted to detect dehydration by having a subject simply raise an arm (arm-raising test) with the flow meter attached to a fingertip. Healthy young volunteers (20 men and two women, mean age 22.9, age range 21-27 years) were instructed to perspire in a sauna until they became dehydrated. The target dewatering ratio was 2 per cent, which was calculated from the body weight measured using a weight scale. Four markers were compared: mean blood flow (MBF) before arm-raising, MBF during arm-raising, maximum amplitude (MA) of the pulse wave during arm-raising, and inclination of reflex (IR) wave calculated from the recorded blood flow data for the non-dehydrated (before sauna) and dehydrated (3h after sauna) states in the arm-raising test. Each of the mean total markers (MBF during arm-raising, MA, and IR) was significantly lower (P < 0.05) during the dehydrated state than the non-dehydrated. These results suggest that three markers could detect dehydration and the blood flow meter devised has the potential to be used as a portable device for detecting dehydration..|
|1.||Hirofumi Nogami, Kosuke Komatsutani, Tomoki Hirata, Renshi Sawada, Integrated laser Doppler blood flowmeter combining optical contact force, ICEP2019, 2019.04, Laser Doppler blood flowmeter (LDF) is a non-invasive method for measuring micro circulation, and has been developed since 1977. It is necessary to control contact force between a LDF and measurement part (skin surface), in order to obtain accurate blood flow. We suggest new multifunctional sensor modules which can measure both blood flow and contact force. A sensor module has a multi-layer ceramic chip with vertical cavity surface emitting laser (VCSEL), photo diodes, and op-amp circuits, and a hollow shell with a mirror and a lug. Some of incident light penetrates into a finger, and the scattering light, which have biological signal (blood flow) are detected by one photodiode. On the other hand, a photodiode can detect reflecting light from a mirror, which is displaced by a contact force. In this paper, we fabricate multifunctional sensor module and attempt to simultaneously measure the blood flow and contact force..|
|2.||Hirofumi Nogami, MEMS sensor and its application to animal health monitoring system, Joint Workshop between Dalian University of Technology (DUT) and Kyushu University (KU), 2019.04.|
|3.||Hirofumi Nogami, Renshi Sawada, MEMS sensor and its application for health monitoring system, KAIST-Kyushu Univ. 9 th Joint Workshop, 2018.10, To achieve the goal of creating a safer and more secure society, wireless sensor network systems are being used increasingly in applications such as structural health monitoring, human health monitoring, agricultural field monitoring, and animal health monitoring. Structural health monitoring can improve the safety and reliability of buildings, bridges, tunnels, and express highways by detecting damage before it reaches a critical state. This damage is sensed by wireless sensor nodes installed on the structure. Human health monitoring detects sleep disorders, Parkinson's disease, etc., by the logging of a person’s daily walking movements and posture using Global Positioning System (GPS) devices, triaxial accelerometers, and angular velocity sensors. These technologies have also been introduced in agricultural field monitoring, including animal health monitoring. It is believed that wireless sensor nodes attached to animals, in conjunction with wireless health-monitoring systems, can achieve early detection and prevention of diseases, and thus reduce economic losses..|
|4.||野上大史、関友貴, ウシの健康管理のための低消費電力の尾根部装着型脈波センサ, 2018年度精密工学会秋季大会, 2018.09.|
|5.||Hirofumi Nogami, Ryo Inoute, Yuma Hayashida, Renshi Sawada, Integrated micro-displacement sensor and its application to photoplethysmographic sensor, 28th International Symposium on Micro-NanoMechatronics and Human Science, MHS 2017, 2017.12, [URL], Photoplethysmography (PPG) has been widely and commonly used, as it has a wide range of information such as stress level, heart rate interval, respiration rate, blood vessel hardness etc. It is necessary to control contact force between a PPG sensor and measurement part (skin surface), in order to obtain accurate PPG signal. We suggest new sensor module which can measure both pulse wave and contact force. A sensor module has a micro integrated displacement sensor chip with optical source, photo diodes, and op-amp circuits, and a gum flame with a mirror. One photodiode can detect reflecting light from a mirror and measure gum flame displacement, which is displaced by a contact force. On the other hand, some of the incident light penetrates into a finger, and the scattering light, which have biological signal (pulse wave) are detected by one photodiode. In this paper, we fabricate multifunctional sensor module and attempt to simultaneously measure the pulse wave and contact force..|
|6.||Hirofumi Nogami, Ryo Inoue, Yuma Hayashida, Hideyuki Ando, Takahiro Ueno, Renshi Sawada, Multifunctional optical sensor module integrated optical micro displacement sensor and its application to a photoplethysmographic sensor with measuring contact force, 11th International Conference on Biomedical Electronics and Devices, BIODEVICES 2018 - Part of 11th International Joint Conference on Biomedical Engineering Systems and Technologies, BIOSTEC 2018, 2018.01, Photoplethysmography (PPG) is widely and commonly used, as it produces a wide range of information, such as stress level, heart rate interval, respiration rate, blood vessel hardness, etc. It is necessary to control the contact force between a PPG sensor and the measurement location (the skin surface), in order to obtain an accurate PPG signal. We propose new multifunctional sensor modules that can measure both pulse waves and contact force. The sensor module has a micro integrated displacement sensor chip with an optical source, photo diodes, and op-amp circuits, and a gum frame with a mirror. Some incident light penetrates into a finger, and the scattered light, which contains a biological signal (a pulse wave), is detected by one photodiode. The photodiode can also detect reflected light from a mirror, which is displaced by a contact force. In this paper, we fabricate a multifunctional sensor module and attempt to simultaneously measure the pulse wave and contact force..|
|7.||Hirofumi Nogami, Ryo Inoue, Ryuta Shiraishi, Yuki Seki, and Renshi Sawada, Stress monitoring of cows using an integrated optical photoplethysmographic sensor, BIO4APPS2017, 2017.12, Detecting the stress level of cows is one of the important purposes for a cow health monitoring system. This is because high stress causes not only lowered resistance to illnesses but also estrus failure. Both electrocardiographic monitors and photoplethysmographic (PPG) sensors can measure stress intensity. The electrocardiographic monitors, which can accurately measure the rate and rhythm of heartbeats, are useful to detect stress intensity. However, long-term usage is not suitable due to its operating with electrodes. On the other hand, PPG sensors can be attached to the cow’s tail for long term monitoring. Thus, we have developed wearable type PPG sensors and attempted to detect stress intensity..|
|8.||野上大史、野崎太貴、澤田廉士, Wearable Devices for Healthcare, 1stSino-JapanSeminar on Micro/Nano Systems for Biomedical Applications, 2017.03, For the purpose of increased safety and security, wireless sensor network systems are being used increasingly in applications such as structural health monitoring, human health monitoring, agricultural field monitoring, and animal health monitoring [1–4]. Animal health monitoring system can achieve early detection and prevention of diseases and thus reduce economic losses. The wireless sensor nodes attached to animals, in conjunction with a wireless health-monitoring system, detect initial fever, abnormal activity, or stress level of the animals. In this study, we have focused on developing wireless pulse wave sensor to detect stress levels..|
|9.||野上大史、白石隆太、井ノ上涼、永友 康隆、澤田廉士, Stress monitoring of cow by using pulse wave, BIO4APPS2016, 2016.12, Stress monitoring of cow by using pulse wave.|
|10.||野上大史、野崎太貴、澤田廉士, 多層セラミックスパッケージを用いたオペアンプ内蔵超小型ＭＥＭＳ血流量センサの開発, 第8回集積化MEMSシンポジウム, 2016.10, The authors propose a new sensor structure for an integrated laser Doppler blood flow sensor using the multi-layered ceramic substrate. The sensor consisted of a vertical-cavity surface-emitting laser (VCSEL), a photodiode (PD), an Op-amp, a resistor, and a capacitor. Signal of PD was amplified in sensor element, which enabled to decrease reduction of electrical noise. .|
|11.||野上大史、白石隆太、井ノ上涼、澤田廉士, Laser Doppler blood flowmeter for animal health monitoring system, The 7th Japan-China-Korea Joint Conference on MEMS/NEMS2016, 2016.09, The estrus intensity detection of the cow is one of the important purposes for animal health monitoring system. During the time of estrus the engorged vagina can be observed from the outside. The engorged vagina is possible to cause blood flow change. To detect the estrus intensity, we have developed the laser Doppler blood flowmeter sensor element. The sensor element is 3.5 x 5.5 x 1.8mm, which is enable to fabricate wearable wireless sensor node. Using the sensor nodes, we could measure blood flow of the cow in short time. However, measurement of the blood flow was not stable in long term. The cause of the unstable measurement was that the blood flow was sensitive to the contact force between cow’s skin and sensor. The contact force easily changed depending on method of mounting or wagging cow’s tail. In this paper, we incorporated the laser Doppler blood flowmeter sensor element with the force sensor to simultaneously measure the blood flow and the contact force. As a result, we could observe stable measured value of the blood flow and pulse wave at the stable contact pressure. At the unstable contact pressure, the measured value of underwent a lot of changes. In addition, the pulse wave couldn’t be observed. Thus, we propose that the measurement of the blood flow need to correct for the influence of the contact force..|
|12.||野上 大史, 三浦 亮太郎, 岡田 宏尚, 前田 龍太郎, 伊藤 寿浩, Wireless temperature sensor nodes in the Appressed Base of a Calf’s tail, BIO4APPS2015, 2015.12.|
|13.||野上 大史, 新井 鐘蔵, 岡田 宏尚, 伊藤 寿浩, 牛のルーメンモニタリングシステムのための3軸加速度無線センサ端末の開発, 2015年精密工学会秋, 2015.09, We successfully fabricated a minimized wireless sensor node capable of monitoring long term (>600 days) rumen conditions. Rumen conditions had been evaluated by wireless sensor nodes having pH measurements..|
|14.||野上 大史, Temperature sensor for an early diagnosis system of pneumonia in calves, The 3rd Singapore-Japan Research Exchange Seminar, 2014.12, Calves are less able to fight virus or bacterium, and predisposed to respiratory disease such as pneumonia. The death and disease accidents caused by respiratory disease are the highest in all accidents. The effective means for early detection of the respiratory disease are to measure rectal temperature with a thermometer. However the mean cannot be frequently conducted on account of spending too effort in the farm. As a means of requiring little effort, we have developed wireless sensor nodes. The primary advantages of the sensor nodes are flexible and slightly temperature sensor pats. The temperature sensor was mounted on the flexible substrate, and the thickness was 0.8 mm. Thus, we can easily attach the sensor nodes to the base of the calf’s tail, which is one of the highest skin temperature parts, and success to measure the skin temperature..|
|15.||野上 大史, 岡田 宏尚, 新井 鐘蔵, 前田 龍太郎, 伊藤 寿浩, Minimize Wireless Sensor Node Built-in 3-Axis Acceleration Meter for cow’s Rumen Monitoring System, IEEE SENSORS, 2014.11, [URL], We succeed to fabricate minimize wireless sensor node which can monitor rumen condition for long term (600 days over). In previous work, to monitor rumen condition, the wireless sensor node can evaluate the rumen condition with pH measurement system. But the sensor nodes cannot be used for two or three months limited by the volume of the internal liquid of the reference electrode. Also, the sensor nodes are very big along of the internal liquid, which can be though given by mouth of the cow. Thus, we work a new method to monitor rumen
condition with 3-axis acceleration meter. We fabricate the wireless sensor nodes built into 3-axis acceleration meter. Using the sensor nodes, we compare the rumen motility of the force transducer measurement with the 3-axis acceleration data of our sensor nodes. As a result, our sensor nodes can detect sign of the
ruminal typany. In addition, the optimum frequency of the measurement and transmitting turns out 5 seconds. Then, the power consumption is 0.18mA, and the theoretically period of use is 600 days over. Thus, we succeed to develop the wireless sensor nodes which can detect rumen sickness for long term..
|16.||野上 大史, 超小型MEMS血流量センサとその応用例, ２０１４年度日本生理人類学会夏季セミナー, 2014.09.|
|17.||野上 大史, 岡田 宏尚, 宮本 亨, 前田 龍太郎, 伊藤 寿浩, Wearable wireless sensor nodes for an animal health monitoring system, IUMRS-ICA 2014, 2014.08, [URL], To achieve the goal of creating a safer and more secure society, wireless sensor network technology has been a promising approach for a variety of applications, such as structural health monitoring, human body monitoring and animal health monitoring. Animal health monitoring system can achieve early detection and prevention of diseases and thus reduce economic losses. The wireless sensor nodes attached to animals, in conjunction with a wireless health-monitoring system, detect initial fever or abnormal activity of the animals. In this study, we have focused on developing the toughness activity sensors for chickens and the flexible temperature sensors for calves..|
2019.12.18～2019.12.20, BIO4APPS2019, Local chair.
2019.02.08～2019.02.09, 第7回バイオメカニクス研究センター＆エレクトロニクス実装学会九州支部 合同研究会, 司会（Moderator）.
2019.11.19～2019.11.21, 第36回「センサ・マイクロマシンと応用システム」シンポジウム, 論文委員.
2018.03.02～2018.03.02, 第6回バイオメカニクス研究センター＆エレクトロニクス実装学会九州支部 合同研究会, 司会（Moderator）.
2017.03.03～2017.03.03, 第５回バイオメカニクス研究センター＆エレクトロニクス実装学会九州支部 合同研究会, 司会（Moderator）.
2016.09.12～2016.09.14, 日本機械学会 2016年度年次大会, 実行委員補助業務.
2015.12.18～2015.12.20, BIO4APPS2015, Local chair.
2015.10.02～2015.10.03, 日本機械学会 第26回バイオフロンティア講演会, 座長（Chairmanship）.
2015.02.06～2015.02.07, 第3回バイオメカニクス研究センター＆エレクトロニクス実装学会九州支部 合同研究会, 座長（Chairmanship）.
2015.09.14～2015.09.15, 戦略的イノベーション創造プログラム（次世代農林水産業創造技術） 「生体センシング技術を活用した次世代精密家畜個体管理システム」 平成27年度 第1回現地検討会, 現地検討会責任者.
2015.10.02～2015.10.03, 日本機械学会 第26回バイオフロンティア講演会, 実行委員.
2015.12.09～2015.12.11, BIO4APPS2015, Conference Secritariat.
2015.02.06～2015.02.07, バイオメカニクス研究センター＆エレクトロニクス実装学会九州支部, 実行委員.
2017年度～2018年度, 2017年度旭硝子財団研究助成金, 代表, 子牛の気管支炎・肺炎の早期発見を目的とした、呼吸数・心拍数計測システムのための高感度な受光部構造の低消費電力脈波センサの開発.
QIR 九州大学学術情報リポジトリ システム情報科学研究院
- A Proposal on Road Evaluation Method Considering the Effect of Shortening Emergency Medical ...
- Study on Station Square Development at Hub Stations
- Feasibility and Quantification Analysis of Floodwater Utilization
- The Critical Behavior of 1-dimensional Spin System with Infinite Long-range Interaction ...
- A Comparison of Analysis Methods for Estimating Directional Wave Spectrum from HF Ocean Radar