检索结果-内蒙古大学图书馆

The effect of circular cylinder diameter installed the side of advancing blade to savonius water turbine performance by means of myring blade formula for n=1

学校读者我要写书评

暂无评论

AIP Conference Proceedings 2023年第1期2510卷

作者： P. A. Setiawan M. Santoso N. Ariwiyono R. Indarti T. Yuwono W. A. Widodo P. P. S. Lukitadi A. Fuad Marine Engineering Department Politeknik Perkapalan Negeri Surabaya Surabaya Indonesia Marine Electrical Engineering Department Politeknik Perkapalan Negeri Surabaya Surabaya Indonesia Mechanical Engineering Department Institut Teknologi Sepuluh Nopember Surabaya Indonesia Center of Excellence in Automotive Control & System Institut Teknologi Sepuluh Nopember Surabaya Indonesia Student of Marine Engineering Department Politeknik Perkapalan Negeri Surabaya Surabaya Indonesia

This study will analyze the performance of savonius water turbines by using blades with the Myring equation n = 1 and adding a circular cylinder on the side of advancing which is simulated in flowing tank with a height of 800 mm and width of 1100 mm with a current speed of 0.22 m/s. The diameter variation of the circular cylinder used is ds/D = 0.2, 0.3, and 0.4. The numerical analysis uses 2D analysis and CFD method in ANSYS-Fluent software. The results obtained from these variations in torque coefficient values and power coefficient. The results of this study indicate that modifying the myring equation n of 1 and adding a circular cylinder on the advancing side can improve the performance of the Savonius. Savonius water turbine test results on variations of myring n = 1 with cylinder diameter ds/D = 0.4 get the highest power coefficient.

关键词：

Contrast detection is enhanced by deterministic, high-frequency transcranial alternating current stimulation with triangle and sine waveform.

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Potok, Weronika van der Groen, Onno Sivachelvam, Sahana Bächinger, Marc Fröhlich, Flavio Kish, Laszlo B. Wenderoth, Nicole Neural Control of Movement Lab Department of Health Sciences and Technology Zurich8093 Switzerland University of Zurich Federal Institute of Technology Zurich University and Balgrist Hospital Zurich Zurich8057 Switzerland 138602 Singapore Neurorehabilitation and Robotics Laboratory School of Medical and Health Sciences Edith Cowan University Joondalup6027 Australia Department of Psychiatry University of North Carolina at Chapel Hill Chapel HillNC United States Carolina Center for Neurostimulation University of North Carolina at Chapel Hill Chapel HillNC United States Department of Neurology University of North Carolina at Chapel Hill Chapel HillNC United States Department of Cell Biology and Physiology University of North Carolina at Chapel Hill Chapel HillNC United States Department of Biomedical Engineering University of North Carolina at Chapel Hill Chapel HillNC United States Neuroscience Center University of North Carolina at Chapel Hill Chapel HillNC United States Department of Electrical & Computer Engineering Texas A&M University TAMUS 3128 College StationTX77843-3128 United States

Stochastic Resonance (SR) describes a phenomenon where an additive noise (stochastic carrier-wave) enhances the signal transmission in a nonlinear system. In the nervous system, nonlinear properties are present from the level of single ion channels all the way to perception and appear to support the emergence of SR. For example, SR has been repeatedly demonstrated for visual detection tasks, also by adding noise directly to cortical areas via transcranial random noise stimulation (tRNS). When dealing with nonlinear physical systems, it has been suggested that resonance can be induced not only by adding stochastic signals (i.e., noise) but also by adding a large class of signals that are not stochastic in nature which cause "deterministic amplitude resonance" (DAR). Here we mathematically show that high-frequency, deterministic, periodic signals can yield resonance-like effects with linear transfer and infinite signal-to-noise ratio at the output. We tested this prediction empirically and investigated whether non-random, high-frequency, transcranial alternating current stimulation applied to visual cortex could induce resonance-like effects and enhance performance of a visual detection task. We demonstrated in 28 participants that applying 80 Hz triangular-waves or sine-waves with tACS reduced visual contrast detection threshold for optimal brain stimulation intensities. The influence of tACS on contrast sensitivity was equally effective to tRNS-induced modulation, demonstrating that both tACS and tRNS can reduce contrast detection thresholds. Our findings suggest that a resonance-like mechanism can also emerge when deterministic electrical waveforms are applied via tACS. Copyright © 2023, The Authors. All rights reserved.

关键词： Stochastic systems

MyoPS: A Benchmark of Myocardial Pathology Segmentation Combining Three-Sequence Cardiac Magnetic Resonance Images

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Li, Lei Wu, Fuping Wang, Sihan Luo, Xinzhe Martín-Isla, Carlos Zhai, Shuwei Zhang, Jianpeng Liu, Yanfei Zhang, Zhen Ankenbrand, Markus J. Jiang, Haochuan Zhang, Xiaoran Wang, Linhong Arega, Tewodros Weldebirhan Altunok, Elif Zhao, Zhou Li, Feiyan Ma, Jun Yang, Xiaoping Puybareau, Elodie Oksuz, Ilkay Bricq, Stephanie Li, Weisheng Punithakumar, Kumaradevan Tsaftaris, Sotirios A. Schreiber, Laura M. Yang, Mingjing Liu, Guocai Xia, Yong Wang, Guotai Escalera, Sergio Zhuang, Xiahai School of Data Science Fudan University Shanghai China School of Biomedical Engineering Shanghai Jiao Tong University Shanghai China Departament de Matemàtiques & Informàtica Universitat de Barcelona Barcelona Spain Computer Vision Center Universitat Autònoma de Barcelona Spain School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Chengdu China School of Computer Science and Engineering Northwestern Polytechnical University Xi'An China College of Electrical and Information Engineering Hunan University Changsha China National Engineering Laboratory for Robot Visual Perception and Control Technology Changsha China College of Physics and Information Engineering Fuzhou University Fuzhou China Comprehensive Heart Failure Center Wuerzburg University Hospitals Wuerzburg Germany School of Engineering University of Edinburgh Edinburgh United Kingdom School of Robotics Xi'an Jiaotong-Liverpool University Suzhou China Department of Electrical and Computer Engineering University of California Los Angeles United States Department of Radiology and Diagnostic Imaging University of Alberta Edmonton Canada Chongqing Key Laboratory of Image Cognition Chongqing University of Posts and Telecomm-Unications Chongqing China ImViA Laboratory Université Bourgogne Franche-Comté Dijon France Computer Engineering Department Istanbul Technical University Istanbul Turkey Le Kremlin-Bicêtre France Department of Mathematics Nanjing University of Science and Technology Nanjing China Department of Mathematics Nanjing University Nanjing China

Assessment of myocardial viability is essential in diagnosis and treatment management of patients suffering from myocardial infarction, and classification of pathology on myocardium is the key to this assessment. This work defines a new task of medical image analysis, i.e., to perform myocardial pathology segmentation (MyoPS) combining three-sequence cardiac magnetic resonance (CMR) images, which was first proposed in the MyoPS challenge, in conjunction with MICCAI 2020. The challenge provided 45 paired and pre-aligned CMR images, allowing algorithms to combine the complementary information from the three CMR sequences for pathology segmentation. In this article, we provide details of the challenge, survey the works from fifteen participants and interpret their methods according to five aspects, i.e., preprocessing, data augmentation, learning strategy, model architecture and post-processing. In addition, we analyze the results with respect to different factors, in order to examine the key obstacles and explore potential of solutions, as well as to provide a benchmark for future research. We conclude that while promising results have been reported, the research is still in the early stage, and more in-depth exploration is needed before a successful application to the clinics. Note that MyoPS data and evaluation tool continue to be publicly available upon registration via its homepage (***/zhuangxiahai/0/myops20/). © 2022, CC BY-NC-SA.

关键词： Magnetic resonance imaging

Strategies for Defending a Coastline Against Multiple Attackers 58

学校读者我要写书评

暂无评论

Strategies for Defending a Coastline Against Multiple Attack...

58th IEEE Conference on Decision and control, CDC 2019

作者： Garcia, Eloy Moll, Alexander Von Casbeer, David W. Pachter, Meir Wright-Patterson AFB Control Science Center of Excellence Air Force Research Laboratory OH45433 United States Wright-Patterson AFB Department of Electrical Engineering OH45433 United States

ISBN: (纸本)9781728113982

A scenario is considered where a coastline or border is coming under attack by two aircraft. The maritime border is guarded by a faster defender bent on intercepting both aircraft in sequence. A differential game is formulated where the defender sequentially pursues both aircraft and tries to capture them as far as possible from the border. The two aircraft cooperate and try to minimize their combined distance to the border at the moment when each one is intercepted by the defender. In this paper, the regular solution of this differential game is obtained and the game's singular surfaces are identified. © 2019 IEEE.

关键词： Aircraft

The complete differential game of active target defense

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Garcia, Eloy Casbeer, David W. Pachter, Meir Control Science Center of Excellence Air Force Research Laboratory Wright-Patterson AFBOH45433 Department of Electrical Engineering Air Force Institute of Technology Wright-Patterson AFBOH45433

In the Target-Attacker-Defender (TAD) differential game, an Attacker missile strives to capture a Target aircraft. The Target tries to escape the Attacker and is aided by a Defender missile which aims at intercepting the Attacker before the latter manages to close in on the Target. The conflict between these intelligent adversaries has been suitably modeled as a zero-sum differential game. Optimal strategies have been synthesized covering the region of the state space where the Target/Defender team is able to win the game. However, the Game of Degree in the Attacker's region of win has not been fully addressed. Preliminary attempts at designing the players' strategies have not been proven to be optimal in the differential game sense. The main results of the paper present the optimal strategies of the Game of Degree in the Attacker's winning region of the state space. It is proven that the obtained strategies provide the saddle-point solution of the game;the Value function is obtained and it is shown to be continuous and continuously differentiable. It is also demonstrated that it is the solution of the Hamilton-Jacobi-Isaacs (HJI) equation. Finally, the obtained strategies are compared to recent results addressing the TAD differential game in [22]. It is shown by counterexample that the strategies proposed in [22] are not optimal. The unique regular solution of this differential game that actually provides a semipermeable Barrier surface is synthesized and verified in this paper. Copyright © 2020, The Authors. All rights reserved.

关键词： Game theory

Model-based event-triggered control over lossy networks

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Garcia, Eloy Antsaklis, Panos J. Control Science Center of Excellence Air Force Research Laboratory Wright-Patterson AFB OH45433 United States Department of Electrical Engineering University of Notre Dame Notre DameIN46556 United States

The event-triggered control problem over lossy communication networks is addressed in this paper. Although packet dropouts have been considered in the implementation of event-triggered controllers, the assumption of protocols that employ acknowledgement messages persists. This paper provides an approach that relaxes such assumption. An event-based controller is implemented at the sensor node of the networked and uncertain system and it transmits feedback measurements to the controller node at asynchronous time instants. The transmitted packets of information are subject to dropouts by the lossy network. We show that the uncertain system can be asymptotically stabilized, that a positive minimum inter-event time exists, and that the proposed approach does not require acknowledgement messages. Copyright © 2020, The Authors. All rights reserved.

关键词： controllers

A differential game approach for beyond visual range tactics

学校读者我要写书评

暂无评论

arXiv 2020年

作者： Garcia, Eloy Casbeer, David W. Tran, Dzung Pachter, Meir Control Science Center of Excellence Air Force Research Laboratory Wright-Patterson AFB OH45433 United States Department of Electrical Engineering Air Force Institute of Technology Wright-Patterson AFB OH45433 United States

An operational relevant conflict between teams of autonomous vehicles in the Beyond Visual Range domain is addressed in this paper. Optimal strategies are designed in order for a team of air interceptors to protect a high value asset and block the attacking team at a safe distance from such asset. The attacking agents take specific roles of leader and wingman and also devise their own optimal strategies in order to launch an attack as close as possible from the asset. The problem is formulated as a zero-sum differential game between players with different speed over two stages: the attack and the retreat stages. For each stage the state-feedback optimal strategies of each player are derived in analytical form. Copyright © 2020, The Authors. All rights reserved.

关键词： Optimal systems

A Two-team Linear Quadratic Differential Game of Defending a Target

学校读者我要写书评

暂无评论

A Two-team Linear Quadratic Differential Game of Defending a...

American control Conference

作者： Eloy Garcia David W. Casbeer Meir Pachter Jess W. Curtis Emily Doucette Control Science Center of Excellence Air Force Research Laboratory Wright-Patterson AFB OH Department of Electrical Engineering Air Force Institute of Technology Wright-Patterson AFB OH Munitions Directorate AFRL Eglin AFB FL

ISBN: (数字)9781538682661

ISBN: (纸本)9781538682678

In this paper we consider the operational scenario where two missiles (attackers) are launched against a stationary target. Two interceptor missiles are fired in order to intercept the attackers. A non-homogeneous scenario is considered where the two attackers represent different levels of threat to the target and it it desired to be able to redirect an interceptor accordingly. The problem is posed as a Linear Quadratic Differential Game (LQDG) with several representative terminal weights and where the players also consider their energy expenditure. The closed-form solution to this zero-sum differential game which can be implemented in a state feedback form is provided in this paper. This type of solution is highly desirable in differential games since only by implementing closed-loop state feedback strategies the players are able to exploit non-optimal plays by the opponent and shift the Value of the game in their favor.

关键词： differential games Attackers Linear quadratic Players Energy Expenditure State feedback Zero

Robust Impedance control for Dual User Haptic Training System

学校读者我要写书评

暂无评论

Robust Impedance Control for Dual User Haptic Training Syste...

RSI/ISM International Conference on robotics and Mechatronics (ICROM)

作者： R. Heidari M. Motaharifar H. D. Taghirad Advanced Robotics and Automated Systems (ARAS) Industrial Control Center of Excellence (ICCE) Faculty of Electrical Engineering K.N. Toosi University of Technology Tehran Iran

ISBN: (数字)9781728166049

ISBN: (纸本)9781728166056

In this paper, an impedance controller with switching parameters for a dual-user haptic training system is introduced. The trainer and the trainee are connected through their haptic consoles, and the trainee performs the surgical procedure on the environment. The trainer can intervene in the procedure by pressing a mechanical pedal; thus, the control parameters are switched to transfer the authority over the task from the trainee to the trainer. The stability of each subsystem and the closed-loop stability of the overall system are investigated. The simulation results verify the performance of the proposed controller.

关键词： Haptic interfaces Impedance Surgery Training Mathematical model Stability analysis Force