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Elliptic Curves Over A p-adic Field With Fake Ordinary Good Reduction
Get PDFWe investigate the structure of the kernel of the Albanese map for a product of curves over a p-adic field. Specifically, we prove that the kernel becomes p-divisible when the ramification of the base field is sufficiently small.departmental bulletin pape
Development of a rimless wheel robot with telescopic legs for step adaptability
Get PDFIn this study, we developed a rimless wheel robot with elastic telescopic legs that can overcome steps. Numerical studies have shown that a rimless wheel robot with elastic telescopic legs has high adaptability to steps. However, rimless wheel robots that can walk in environments with steps have not yet been developed. To develop a rimless wheel robot that could overcome the steps, we initially developed a three-dimensional model of the robot through Unity software and simulated its walking on level ground and surfaces with steps. Then, we determined the optimal elasticity of the elastic telescopic legs through numerical simulation and constructed a model with optimized parameters. Finally, we conducted the walking experiments employing the developed robot. The robot can walk on level ground and surfaces with steps.journal articl
Recognizing Nursing Activities in Endotracheal Suction: Utilizing Multiple Readouts Reservoir Computing and Large Language Models
Get PDFIdentifying nursing activity during critical procedures, such as endotracheal suction (ES), is crucial for ensuring patient safety and the quality of received treatment. The expansion of home care requires an increase in the number of certified professionals who can perform endotracheal procedures and provide monitoring during these activities. To fulfill these needs, this study aims to develop an algorithm that is able to recognize ES activities that have the potential to be implemented on edge devices and perform real-time processing of nurse’s pose keypoint extracted from the video using YOLOv7, which is represented in x and y coordinates. The edge device implementation is crucial for health care for ensuring security and privacy, and reducing cost network congestion and latency. In this study, we introduce a combination of a reservoir computing (RC)-based recognition model and large language models (LLMs) to identify nursing activities related to endotracheal suction. RC is suitable for edge device implementation because of its low computational cost requirement and processes temporal features necessary for recognizing nursing activity in real-time. To enhance the performance of RC, we introduce a reservoir computing model with multiple readouts for the recognition model, called RCMRO. The proposed model, which uses LLMs to analyze keypoint data and generate synthetic training data to improve the performance of RCMRO, shows promising performance in distinguishing between various nursing activities. This tool provided healthcare professionals with a prospective method to monitor and evaluate nursing activity in real-time and achieved an accuracy of 70.5% and an F1 score of 68.1% when evaluated by using a test dataset.journal articl
Characterization of Catheter-Type Tactile Sensor Using Polyvinylidene Fluoride (PVDF) Film
Get PDFTo enable quantitative palpation in vivo, we previously developed a catheter-type tactile sensor with an outer diameter of 2 mm composed of a polyvinylidene fluoride (PVDF) film for minimally invasive surgery. However, our previous studies did not evaluate the effect of the PVDF film shape on the sensor output. In this study, we fabricated three types of prototype sensors with different PVDF film shapes and sizes using a simple cutting method. One of the films had the same shape as that used in one of our previous studies. We also prepared two types of PVDF film with a wide base and a narrow tip because we assumed that the deformation of the sensor gradually decreases from the root to the tip, similar to the first mode of the natural frequency. We evaluated the frequency response of the proposed sensors by vibrating the sensor tip and compared the results with the theoretical values. It was confirmed that the sensor output increased with PVDF film size. Although this tendency was observed for both the measured and theoretical values, the measured values were smaller than the theoretical values. Moreover, the effect of film size was larger than that of film shape. Improvements in the sensor structure and the theoretical equation and better evaluation methods are required in order to optimize the film shape and size.journal articl
Static Hand Gesture Recognition Based on Multi-Feature Extraction with Context for User Intension
Get PDFDressing is a critical component of Activity of Daily Living (ADLs). The development of assistive technology for dressing tasks is urgently needed from the viewpoint of privacy, for example, to prevent the wearer from being seen in the nude. Despite their importance, these technologies are underutilized in garment donning compared to other ADLs. The reasons for the lack of utilization of assistive technology are that the task is complex, as it involves handling individuals with large individual differences in height and symptoms and requires manipulation of flexible clothing. Addressing these variances presents a formidable academic challenge. Our previous study identified periodic patterns in human movements during robot-assisted dressing and noted individual variability in these patterns. Capitalizing on this finding, we propose a novel control strategy for a robot that adapts to individual needs during dressing, employing the "Assist-As-Needed" (AAN) principle from physical therapy. The proposed control method uses Central Pattern Generators (CPG) that can be synchronously controlled in response to external forces, enabling model-free control without human modeling.
We utilize the Rowat-Selverston CPG model, which is recognized for its adaptive response to human motions in human-robot interactions such as with handshaking robots. A simulator of the Rowat-Selverston CPG was created. The output of the CPG was confirmed by inputting the data set obtained in previous studies, and the parameters were adjusted. The CPG output was then applied to the recorded target joint trajectory for the dressing assistance. We prepared a replay of the default trajectory, a trajectory with simple harmonic motion applied, and a trajectory with CPG output applied, and confirmed whether individual adaptation according to the AAN was possible through subject experiments. The experimental results showed that the Rowat-Selverston CPG control method enables individual adaptive dressing assistance according to the AAN principle. This study summarizes these methods and results and contributes to the realization of an individually adaptive system that follows the AAN principle, especially in developing assistive technology.journal articl
Effect of freeze-thaw history on reinforcement effect of vegetation work using Phalaris arundinacea L.
Get PDF本研究では，在来種のクサヨシ（Phalaris arundinacea L.）を生育させた供試体を凍上性の高い砂質土で作製し，凍結融解履歴を与えた上で低鉛直応力の定圧一面せん断試験を実施した。試験結果から，クサヨシの根系を含む土供試体のせん断抵抗は凍結融解履歴を受けて幾分低下するものの，地盤補強効果そのものは失われていないことがわかった。特に，既往研究で確認された大きなせん断変位においてせん断抵抗が増加する延性的な挙動は，凍結融解履歴を受けた後でも維持されていることが確認できた。以上の成果から，クサヨシは積雪寒冷地において植生工を行う際に用いる地域性種苗として，極めて有望であることがわかった。In this study, specimens grown with reed canary grass (Phalaris arundinacea L.) were prepared using highly frost-susceptible sandy soil. These specimens were subjected to a freeze-thaw history, and then subjected to constant-pressure direct shear tests at low vertical stress. The test results showed that the shear resistance of the soil specimen containing the root system of reed canary grass decreased somewhat owing to the freeze-thaw history, but the soil reinforcement effect itself was not lost. In particular, the ductile behavior of the shear resistance increasing at a large shear displacement observed in previous studies was maintained after freeze-thaw history. These results indicate that reed canary grass is a very promising seed or seedling for use in vegetation work in snowy and cold regions.journal articl
Spatio-temporal analysis of sand-density distribution beneath traveling wheel based on particle image velocimetry
Get PDFThis paper proposes a spatio-temporal analysis of sand-density distribution beneath a traveling wheel based on a particle image velocimetry (PIV) method. With the advancement of image processing technology and the higher resolution of commercially available digital cameras, the PIV methods have been widely used to directly visualize the sand flow field without tracer particles. They can output the numerous sand velocity vectors at a moment in time. By continuously connecting sand flow fields obtained, we can surmise their spatio-temporal changes, though, each flow field is obtained as a spatio-temporally independent feature. Thus, we attempt to propose a PIV-based spatio-temporal analysis accumulating the sand flow vectors, and thereby show a spatio-temporal change of the sand-density distributions beneath the traveling wheel, where the sand density is represented by the relative density. Although the method requires some assumptions, it can represent the spatio-temporal behavior of the sandy terrain, which has not been shown before.conference pape
Рассмотрение японо-советского академического обмена в Научном совете Японии (1955–1964)
Get PDFThis paper aims to clarify the circumstances surrounding the resumption of scientific exchange between Japan and the Soviet Union in the 1950s. The first official academic exchanges between the two countries after the World War II began in May 1955, when 15 members of the Science Council of Japan (SCJ), a representative academic institution in Japan, accepted an invitation from the USSR Academy of Sciences and visited Russia on a scientific inspection tour. Following this visit, interest in Russian studies grew in Japanese academia. In October 1956 the Japan-Soviet Joint Declaration was issued and diplomatic relations were restored. Under these circumstances, the plan to invite Soviet scientists to Japan became a pressing issue. However, it was not until March 1964 that Soviet scientific delegates, including M.V. Keldysh, finally visited Japan. During the moratorium period of about 10 years, the SCJ continued to discuss the invitation of scientists from the Soviet Union at every General Assembly, but the invitation plan progressed very slowly due to the rejection of the budget request required for the invitation and the lack of a cultural exchange agreement between the two countries. This paper uses the stenographic records of the General Assembly of the SCJ (unpublished documents) to shed light on some of the background to the efforts to resume scientific exchange between the two countries.Целью данной статьи является выяснение обстоятельств возобновления научного обмена между Японией и Советским Союзом в 1950-х гг. Первые официальные академические обмены между двумя странами после Второй мировой войны начались в мае 1955 г., когда 15 членов Научного совета Японии (SCJ), представительного академического учреждения в Японии, приняли приглашение Академии наук СССР и посетили Россию с научным обзором. После этого визита в японских академических кругах возрос интерес к изучению России. В октябре 1956 г. была опубликована Совместная японо-советская декларация и восстановлены дипломатические отношения. В этих обстоятельствах план приглашения советских ученых в Японию стал насущным вопросом. Однако только в марте 1964 г. советская научная делегация, куда в том числе входил М.В. Келдыш, наконец посетила Японию. В течение периода моратория, длившегося около 10 лет, Научный совет продолжал обсуждать приглашение ученых из Советского Союза на каждой Генеральной ассамблее, но план приглашения продвигался очень медленно из-за отклонения запросов средств, необходимых для приглашения, и отсутствия соглашения о культурном обмене между двумя странами. В этой статье используются стенографические записи Генеральной ассамблеи Верховного суда (неопубликованные документы), чтобы пролить свет на некоторые предпосылки усилий по возобновлению научного обмена между двумя странами.journal articl
Performance Evaluation for the Impact of TCP Congestion Control Algorithms in Low Earth Orbit Satellite Communication
Get PDF米国SpaceX社が提供するサービスである，Starlinkは，地球の低軌道に通信衛星を配置する低軌道衛星通信であり，広範囲に高速で安定したインターネットアクセスを提供している. 通信インフラが整備されていない遠隔地や地域においても利用可能であり，農村部や開発途上国での利用が期待されている．しかし，このような低軌道衛星通信システムは，地上のインターネットと比べて変動が大きい通信環境であることから，固有の問題も抱えている．従来のインターネットにおけるエンドツーエンド通信では，TCPにより経路中の輻輳状態に応じて適切なレートでデータを送信する．しかし、低軌道衛星通信システムにおいては低軌道衛星と基地局間の通信を要するため，輻輳制御アルゴリズムによっては通信性能に影響を与える可能性がある．そこで本研究では，低軌道衛星通信回線の一つであるStarlink のBusiness とResidentialの2つの回線を用いて，異なる輻輳制御アルゴリズムを用いた場合における通信性能を評価する．Starlink, which is provided by the American company SpaceX provides a satellite internet constellation using Low-Earth orbit (LEO) satellite. The Starlink can achieve high-speed and stable internet access over the world. However, such a LEO satellite communication system have various challenges due to large delay variation compared to traditional ground-based internet. In conventional end-to-end communication over the Internet, TCP adjusts the data transmission rate appropriately based on congestion states in the network. However, since LEO satellite communication systems require communication between the satellites and base stations, some congestion control algorithms may affect communication performance. Therefore, this study aims to evaluate the communication performance with different congestion control algorithms using the Starlink.電子情報通信学会 インターネットアーキテクチャ研究会（IA）, 2024年3月12日-14日, 宮古島市未来創造センターjournal articl