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Model-free method for LQ mean-field social control problems with one-dimensional state space

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Control Theory and Technology 2024年第3期22卷 479-486页

作者： Zhenhui Xu Tielong Shen School of Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan Department of Engineering and Applied Sciences Sophia UniversityTokyo 102-8554Japan

This paper presents a novel model-free method to solve linear quadratic(LQ)mean-field control problems with one-dimensional state space and multiplicative *** focus is on the infinite horizon LQ setting,where the conditions for solution either stabilization or optimization can be formulated as two algebraic Riccati equations(AREs).The proposed approach leverages the integral reinforcement learning technique to iteratively solve the drift-coefficient-dependent stochastic ARE(SARE)and other indefinite ARE,without requiring knowledge of the system dynamics.A numerical example is given to demonstrate the effectiveness of the proposed algorithm.

关键词： Mean-field control Social optima Infinite horizon Reinforcement learning

Optimization of body configuration and joint-driven attitude stabilization for transformable spacecraft under solar radiation pressure

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Astrodynamics 2024年第1期8卷 47-60页

作者： Yuki Kubo Toshihiro Chujo Institute of Space and Astronautical Science Japan Aerospace Exploration AgencyKanagawa252-5210Japan Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo152-8550Japan

The solar sail is one of the most promising space exploration systems due to its theoretically infinite specific impulse achieved through solar radiation pressure(SRP).Recently,researchers have proposed“transformable spacecraft”capable of actively reconfiguring their body configurations using actuatable *** spacecraft,if used similarly to solar sails,are expected to significantly enhance orbit and attitude control capabilities owing to their high redundancy in control degrees of ***,controlling them becomes challenging due to their large number of inputs,leading previous researchers to impose strong constraints to limit their potential control *** study focuses on novel attitude control techniques for transformable spacecraft under *** developed two methods,namely,joint angle optimization to obtain arbitrary SRP force and torque,and momentum damping control driven by joint angle *** proposed methods are formulated in a general manner and can be applied to any transformable spacecraft comprising front faces that can predominantly receive the SRP on each *** validity of our proposed method is confirmed through numerical *** study contributes to making most of the high control redundancy of transformable spacecraft without the need for expendable propellants,thus significantly enhancing the orbit and attitude control capabilities.

关键词： solar sail transformable spacecraft attitude-joint coupled motion attitudestabilization

Non-Kramers doublet ground state in a quaternary cubic compound PrRu_(2)In_(2)Zn_(18) investigated by ultrasonic measurements

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Chinese Physics B 2024年第6期33卷 405-411页

作者：张化远 Kazuhei Wakiya Mitsuteru Nakamura Masahito Yoshizawa Yoshiki Nakanish Graduate School of Science and Engineering Iwate UniversityMorioka 020-8551Japan

We performed ultrasonic measurements on a quaternary cubic compound PrRu_(2)In_(2)Zn_(18) to explore the ground state properties derived from non-Kramers Γ_(3) doublet of Pr^(3+).PrRu_(2)In_(2)Zn_(18) is a quaternary derivative of the ternary compound PrRu_(2)Zn_(20) that exhibits a structural phase transition at T_S=138 *** PrRu_(2)In_(2)Zn_(18),the Zn atoms at the 16c site in PrRu_(2)Zn_(20) are selectively replaced by In atoms.A monotonic increase was observed in the temperature dependence of elastic constants C_L=(C_(11)+2C_(12)+4C_(44))/3 and C_(T)=(C_(11)-C_(12)+C_(44))/3 in the temperature range around T_(S) to which an elastic softening was observed in(C_(11)-C_(12))/2 for PrRu_(2)Zn_(20).The disappearance of the softening indicates that the structural transition in PrRu_(2)Zn_(20) is suppressed by the substitution of Zn ions by In ones with a larger ionic ***,the C_(T) of PrRu_(2)In_(2)Zn_(18) exhibits a precursor Curie-type elastic softening toward low temperatures being responsible for the non-Kramers Γ_(3) ground *** discuss the ground state and the evolution of the elastic properties of the different single-crystal samples of PrRu_(2)In_(2)Zn_(18) grown under different conditions.

关键词： ultrasonic measurements non-Kramers doublet structural phase transition crystalline electric field effect

Controlling a peristaltic robot inspired by inchworms

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Biomimetic Intelligence & Robotics 2024年第1期4卷 88-96页

作者： Yanhong Peng Hiroyuki Nabae Yuki Funabora Koichi Suzumori Department of Information and Communication Engineering Graduate School of EngineeringNagoya UniversityNagoya 464-8601Japan Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan

This study presents an innovative approach in soft robotics,focusing on an inchworm-inspired robot designed for enhanced transport *** explore the impact of various parameters on the robot’s performance,including the number of activated sections,object size and material,supplied air pressure,and command execution *** a series of controlled experiments,we demonstrate that the robot can achieve a maximum transportation speed of 8.54 mm/s and handle loads exceeding 100 g,significantly outperforming existing models in both speed and load *** findings provide valuable insights into the optimization of soft robotic design for improved efficiency and adaptability in transport *** research not only contributes to the advancement of soft robotics but also opens new avenues for practical applications in areas requiring precise and efficient object *** study underscores the potential of biomimetic designs in robotics and sets a new benchmark for future developments in the field.

关键词： McKibben artificial muscles Bionics Soft robotics Soft actuator Bio-inspired robotics

Impacts of different pancreatic resection ranges on endocrine function in Suncus murinus

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World Journal of Gastrointestinal Surgery 2024年第7期16卷 2308-2318页

作者： Ru-Jia Li Ting Yang Yu-Hao Zeng Yutaro Natsuyama Ke Ren Jun Li Yuichi Nagakawa Shuang-Qin Yi Department of Frontier Health Sciences Graduate School of Human Health SciencesTokyo Metropolitan UniversityTokyo 116-8551Japan Faculty of Physical Education Qujing Normal UniversityQujing 655000Yunnan ProvinceChina School of Medicine Shanghai Cancer InstituteShanghai Jiao Tong UniversityShanghai 200240China Department of Gastrointestinal and Pediatric Surgery Tokyo Medical UniversityTokyo 160-0023Japan

BACKGROUND Surgical intervention involving the pancreas can lead to impaired glucose tolerance and other types of endocrine *** scope of pancreatectomy and whether it includes the ventral pancreas are the key factors in the development of postoperative *** ventral and dorsal pancreases are almost separated in Suncus murinus(***).AIM To investigate the effects of different extents of pancreatic resection on endocrine function in *** Eight-week-old male *** shrews were randomly divided into three experimental groups according to different pancreatic resection ranges as follows:ventral pancreatectomy(VPx)group;partial pancreatectomy(PPx)group;subtotal pancreatectomy(SPx)group;and a sham-operated *** serum insulin,glucagon-like peptide-1(GLP-1),pancreatic polypeptide(PP),and somatostatin(SST)levels,as well as food intake,weight,blood glucose,and glucose tolerance were regularly measured for each *** *** treated with PPx and SPx suffered from varying degrees of impaired glucose tolerance,but only a small proportion of the SPx group developed *** *** in the SPx group showed a significant decrease in food intake accompanied by severe weight loss,as well as a significant increase in postprandial serum GLP-1 *** serum PP levels decreased in both the VPx and PPx groups,but not in the SPx *** serum SST levels decreased in both VPx and PPx groups,but the decrease was *** Severe weight loss after pancreatectomy may be related to loss of appetite caused by compensatory elevation of *** and GLP-1 may play a role in resisting blood glucose imbalance.

关键词： Pancreatectomy Glucose homeostasis Endocrine dysfunction Glucagon-like peptide-1 Pancreatic polypeptide

Computer-controlled ultra high voltage amplifier for dielectric elastomer actuators

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Biomimetic Intelligence & Robotics 2024年第1期4卷 14-23页

作者： Ardi Wiranata Zebing Mao Yu Kuwajima Yuya Yamaguchi Muhammad Akhsin Muflikhun Hiroki Shigemune Naoki Hosoya Shingo Maeda Department of Mechanical and Industrial Engineering University of Gadjah MadaYogyakarta 55281Indonesia Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan Department of Engineering and Science Shibaura Institute of TechnologyTokyo 135-8548Japan Department of Electrical Engineering Shibaura Institute of TechnologyTokyo 135-8548Japan Department of Engineering Science and Mechanics Shibaura Institute of TechnologyTokyo 135-8548Japan Living Systems Materialogy(LiSM)Research Group International Research Frontiers Initiative(IRFI)Tokyo Institute of TechnologyYokohama 226-8501Japan

Soft robotics is a breakthrough technology to support human-robot *** soft structure of a soft robot can increase safety during human and robot *** of the promising soft actuators for soft robotics is dielectric elastomer actuators(DEAs).DEAs can operate silently and have an excellent energy *** simple structure of DEAs leads to the easy fabrication of soft *** simplicity combined with silent operation and high energy density make DEAs interesting for soft robotics *** actuation follows the Maxwell-pressure *** pressure produced in the DEAs actuation depends much on the voltage *** DEAs requires high voltage to gain an *** the power consumption of DEAs is in the milli-Watt range,the current needed to operate the DEAs can be *** commercially available DC-DC converters can convert the volt range to the kV *** order to get a voltage in the 2-3 kV range,the reliable DC-DC converter can be pricy for each *** problem hinders the education of soft actuators,especially for a newcomer laboratory that works in soft electric *** paper introduces an entirely do-it-yourself(DIY)Ultrahigh voltage amplifier(UHV-Amp)for education in soft ***-Amp can amplify 12 V to at a maximum of 4 kV *** a demonstration,we used this UHV-Amp to test a single layer of powdered-based *** strategy to build this educational type UHV-Amp was utilizing a Cockcroft-Walton circuit structure to amplify the voltage range to the kV *** its current state,the UHV-Amp has the potential to achieve approximately 4 *** created a simple platform to control the UHV-Amp from a personal *** near future,we expect this easy control of the UHV-Amp can contribute to the education of soft electric actuators.

关键词： Dielectric elastomer actuators Electric amplifier Soft actuators Soft robotics Soft actuator education

A Review of Contact Electrification at Diversified Interfaces and Related Applications on Triboelectric Nanogenerator

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Nano-Micro Letters 2024年第1期16卷 106-130页

作者： Jun Hu Mitsumasa Iwamoto Xiangyu Chen CAS Center for Excellence in Nanoscience Beijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 100083People’s Republic of China School of Nanoscience and Engineering University of Chinese Academy of SciencesBeijing 100049People’s Republic of China Department of Physical Electronics Tokyo Institute of Technology2‑12‑1 S3‑33 O‑OkayamaMeguro‑KuTokyo 152‑8552Japan

The triboelectric nanogenerator(TENG)can effectively collect energy based on contact electrification(CE)at diverse interfaces,including solid–solid,liquid–solid,liquid–liquid,gas–solid,and gas–*** enables energy harvesting from sources such as water,wind,and *** this review,we provide an overview of the coexistence of electron and ion transfer in the CE *** elucidate the diverse dominant mechanisms observed at different interfaces and emphasize the interconnectedness and complementary nature of interface *** review also offers a comprehensive summary of the factors influencing charge transfer and the advancements in interfacial modification ***,we highlight the wide range of applications stemming from the distinctive characteristics of charge transfer at various ***,this review elucidates the future opportunities and challenges that interface CE may *** anticipate that this review can offer valuable insights for future research on interface CE and facilitate the continued development and industrialization of TENG.

关键词： Contact electrification Interfaces Triboelectric nanogenerators Diversified applications

TendiffPure:a convolutional tensor-train denoising diffusion model for purification

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Frontiers of Information Technology & Electronic Engineering 2024年第1期25卷 160-169页

作者： Mingyuan BAI Derun ZHOU Qibin ZHAO RIKEN AIP Tokyo 1030027Japan School of Environment and Society Tokyo Institute of TechnologyTokyo 1528550Japan

Diffusion models are effective purification methods,where the noises or adversarial attacks are removed using generative approaches before pre-existing classifiers conducting classification ***,the efficiency of diffusion models is still a concern,and existing solutions are based on knowledge distillation which can jeopardize the generation quality because of the small number of generation ***,we propose TendiffPure as a tensorized and compressed diffusion model for *** the knowledge distillation methods,we directly compress U-Nets as backbones of diffusion models using tensor-train decomposition,which reduces the number of parameters and captures more spatial information in multi-dimensional data such as *** space complexity is reduced from O(N^(2))to O(NR^(2))with R≤4 as the tensor-train rank and N as the number of *** results show that TendiffPure can more efficiently obtain high-quality purification results and outperforms the baseline purification methods on CIFAR-10,Fashion-MNIST,and MNIST datasets for two noises and one adversarial attack.

关键词： Diffusion models Tensor decomposition Image denoising

Navigating reflux disease after achalasia treatments:Balancing risks and benefits

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World Journal of Gastroenterology 2024年第21期30卷 2740-2743页

作者： Ewen A Griffiths Enoch Wong Department of Upper Gastrointestinal Surgery University Hospitals Birmingham NHS Foundation TrustBirmingham B152GWWest MidlandsUnited Kingdom Department of Immunology and Immunotherapy University of BirminghamBirmingham B152TTWest MidlandsUnited Kingdom

The peroral endoscopic myotomy(POEM)procedure has revolutionized the management of achalasia in many centres around the world as it offers patients a minimally invasive endoscopic solution to their dysphagia caused by *** its success in alleviating dysphagia,concerns regarding postoperative gastroesophageal reflux disease have emerged as a pertinent issue which are not fully *** this study,Nabi et al have comprehensively reviewed the topic of the prediction,prevention and management of gastroesophageal reflux after *** is a purely endoscopic procedure which is usually performed without any anti-reflux *** patients may be better served by a laparoscopic Heller’s myotomy and fundoplication and it is important that gastroenterologists and surgeons provide comprehensive risks and benefits of each achalasia treatment option so that patients can decide what treatment is best for *** article by Nabi et al provides a comprehensive review of the current status of this issue to allow these discussions to occur.

关键词： Achalasia Gastro-esophageal reflux disease Laparoscopic heller’s myotomy Peroral endoscopic myotomy Fundoplication