检索结果-南通市图书馆

Learning the optimal state-feedback via supervised imitation learning

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Astrodynamics 2019年第4期3卷 361-374页

作者： Dharmesh Tailor Dario Izzo advanced concepts team European Space AgencyNoondwijk2201 AZthe Netherlands

Imitation learning is a control design paradigm that seeks to learn a control policy reproducing demonstrations from expert *** substituting expert demonstrations for optimal behaviours,the same paradigm leads to the design of control policies closely approximating the optimal *** approach requires training a machine learning algorithm(in our case deep neural networks)directly on state-control pairs originating from optimal *** have shown in previous work that,when restricted to low-dimensional state and control spaces,this approach is very successful in several deterministic,non-linear problems in *** this work,we refine our previous studies using as a test case a simple quadcopter model with quadratic and time-optimal objective *** describe in detail the best learning pipeline we have developed,that is able to approximate via deep neural networks the state-feedback map to a very high *** introduce the use of the softplus activation function in the hidden units of neural networks showing that it results in a smoother control profile whilst retaining the benefits of *** show how to evaluate the optimality of the trained state-feedback,and find that already with two layers the objective function reached and its optimal value differ by less than one *** later consider also an additional metric linked to the system asymptotic behaviour-time taken to converge to the policy’s fixed *** respect to these metrics,we show that improvements in the mean absolute error do not necessarily correspond to better policies.

关键词： optimal control deep learning imitation learning G&CNET

Target selection for a small low-thrust mission to near-Earth asteroids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Astrodynamics 2018年第3期2卷 249-263页

作者： Alessio Mereta Dario Izzo advanced concepts team European Space Research and Technology CenterNoordwijk 12201 AZNetherlands

The preliminary mission design of spacecraft missions to asteroids often involves,in the early phases,the selection of candidate target *** final result of such an analysis is a list of asteroids,ranked with respect to the necessary propellant to be used,that the spacecraft could potentially *** this paper we investigate the sensitivity of the produced asteroids rank to the employed trajectory model in the specific case of a small low-thrust propelled spacecraft beginning its journey from the Sun–Earth L2 Lagrangian point and heading to a rendezvous with some near-Earth *** consider five increasingly complex trajectory models:impulsive,Lambert,nuclear electric propulsion,nuclear electric propulsion including the Earth’s gravity,solar electric propulsion including the Earth’s gravity and we study the final correlation between the obtained target *** find that the use of a lowthrust trajectory model is of great importance for target selection,since the use of chemical propulsion surrogates leads to favouring less attractive options 19%of times,a percentage that drops to 8%already using a simple nuclear electric propulsion model that neglects the Earth’s gravity effects and thrust dependence on the solar *** also find that for the study case considered,a small interplanetary CubeSat named M-ARGO,the inclusion of the Earth’s gravity in the considered dynamics does not affect the target selection significantly.

关键词： low-thrust asteroid selection near-Earth asteroids mission analysis

Biomimetics of Campaniform Sensilla:Measuring Strain from the Deformation of Holes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2007年第2期4卷 63-76页

作者： Julian F. V. Vincent Sally E. Clift Carlo Menon Department of Mechanical Engineering The University of BathBath BA2 7AYUK advanced concepts team European Space Agency2201 AZ NoordwijkThe Netherlands

We present a bio-inspired strategy for designing embedded strain sensors in space structures. In insects, the campaniform sensillum is a hole extending through the cuticle arranged such that its shape changes in response to loads. The shape change is rotated through 90° by the suspension of a bell-shaped cap whose deflection is detected by a cell beneath the cuticle. It can be sensitive to displacements of the order of 1 nm. The essential morphology, a hole formed in a plate of fibrous composite mate- rial, was modelled by Skordos et al. who showed that global deformation of the plate （which can be flat, curved or a tube） induces higher local deformation of the hole due to its locally higher compliance. Further developments reported here show that this approach can be applied to groups of holes relative to their orientation. , The morphology of the sensillum in insects suggests that greater sensitivity can be achieved by arranging several holes in a regular pattern; that if the hole is oval it can be ＂aimed＂ to sense specific strain directions; and that either by controlling the shape of the hole or its relationship with other holes it can have a tuned response to dynamic strains. We investigate space applications in which novel bio-inspired strain sensors could successfully be used.

关键词： campaniform sensillum strain displacement compliance hole remote sensing fibrous composite

Tendril-Based Climbing Plants to Model, Simulate and Create Bio-Inspired Robotic Systems

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2015年第2期12卷 250-262页

作者： Renato Vidoni Tanja Mimmo Camilla Pandolfi Faculty of Science and Technology Free University of Bolzano Piazza universith 3 91 O0 Bolzano Italy European Space Agency-advanced concepts team Estec Noordwjik Netherlands

Bioinspiration can be considered one of the keys for future smart and versatile robotic systems. Plants could be an im- portant source of ideas despite the fact that they have not yet been deeply observed and considered. In this paper, climbing tendril-bearer plants that, by means of irritable filiform organs called tendrils, search for a support, grasp it and climb to gain height, have been used to study and develop an effective climbing robot. The study aimed first to evaluate the main movements and behaviors of the tendril from a biomimetic point of view. The tendril complexity was then simplified, a robotic model was developed and a kinematic simulator was designed and implemented to visualize and evaluate the chosen system. Finally, based on the biological, technical and numerical evaluations, the main tendril behaviors were replicated by proof of concept devices made of smart materials to move towards a practical realization and to replicate the simulated results. The designed proof of concept prototypes showed food repeatability and feasibility.

关键词： climbing plants robotic tendril kinematic model Shape-Memory-Alloy (SMA) grasping

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Back to Earth

The Innovation 2023年第3期4卷 83-83页

作者： Matteo Cerri Jurgen Bereiter-Hahn Gerhard Heldmaier Alexander Choukér Leopold Summerer Department of Biomedical and Neuromotor Sciences University of BolognaBolognaItaly Institute for Cell Biology and Neurosciences Department of BiologyGoethe University FrankfurtFrankfurtGermany Laboratory of Translational Research’Stress and Immunity’ Department of AnesthesiologyLMU HospitalLudwig-Maximilian-UniversityMunichGermany Department of Anesthesiology LMU University HospitalMunichGermany advanced concepts and Studies Office European Space AgencyNoordwijkthe Netherlands

On behalf of the Topical team Hibernation of the European Space Agency,we would like to provide some comments on the recently published article"Primate preoptic neurons drive hypothermia and cold defense"by Zhang and colleagues.1 We read the manuscript with high interest and acknowledge that the authors were able to conduct their experiment on non-human primates,a challenging model for both practical and ethical reasons,hereby striving to expand the validity of many experiments in rodents.

关键词： behalf Earth knowledge

Stochastic geometry based analysis for heterogeneous networks: a perspective on meta distribution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2020年第12期63卷 230-250页

作者： Xinlei YU Qimei CUI Yuanjie WANG Na LI Xiaofeng TAO Mikko VALKAMA National Engineering Laboratory for Mobile Network Technologies Beijing University of Posts and Telecommunications National Computer Network Emergency Response Technical team/Coordination Center of China (CNCERT/CC) Department of Electrical Engineering Tampere University

The meta distribution as a new performance metric can provide much more fine-grained information about the individual link reliability, and is of great value for the analysis and design of the future cellular networks. In this paper, we investigate the stochastic geometry based analysis for heterogeneous networks from the perspective on the meta distribution. The comprehensive overview for the fundamental framework of the meta distribution is provided, which involves the concepts of the meta distribution and its related performance metric(e.g., mean local delay and spatial outage capacity) and the efficient calculation methods of the meta distribution. The insights of the meta distribution are also stated by the comparison with standard success probability. The various applications of the meta distribution to heterogeneous networks are summarized and categorized by different types of technologies. Furthermore, some open issues and future work are discussed to promote the development and application of the meta distribution.

关键词： meta distribution stochastic geometry heterogeneous network success probability per-link reliability

TOUCH AND DESIGN （T’ND） A EUROPEAN FUNDED PROJECT

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

TOUCH AND DESIGN （T’ND） A EUROPEAN FUNDED PROJECT

Effect of herbal medicines with bitter taste on the inhibition of whole blood aggregation

The 7th International Conference on Computer-Aided Industrial Design and Conceptual Design (CAID&CD’2006)

作者： Patrick Bosinco Nicolas Rejneri Alain Massabo think3 advanced research and development team 36 Parc club du Golf 13799 Aix en ProvenceCedex 3 FRANCE

Gestures, besides speech, represent the mostly used means of expression by humans. For that regards the product design field, designers have multiple ways for communicating their ideas and concepts. One of them concerns the model making activity, where designers make explicit their concepts by using some appropriate tools and specific hand movements on plastic material with the intent of obtaining a shape. Some studies have demonstrated that visual, tactile and kinesthetic feedbacks are equally important in the shape creation and evaluation process. Moreover current computer aided tools aimed at supporting the conceptual phase of product design are not intuitive to use, and do not exploit designers’ skill and creativity. This paper presents the results of a research work aiming at integrating user-friendly and effective ways of interaction based on ad-hoc haptic interfaces into free-form shape modeling systems. The European project "Touch and Design" （T’nD） proposes the implementation of an innovative virtual clay modeling system based on novel haptic interaction modality oriented to industrial designers. In order to develop an intuitive and easy-to-use system, a study of designers’ hand modeling activities has been carried out by the project industrial partners supported by cognitive psychologists. The users’ manual operators and tools have been translated into corresponding haptic tools and multimodal interaction modalities in the virtual free-form shape modeling system. The paper presents the project research activities, the results achieved so far and the future related work.

关键词： Haptic interfaces Product design Shape Prototypes Space technology Research and development Product development Speech Humans Plastics

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Effect of herbal medicines with bitter taste on the inhibiti...

IoTFLiP： IoT-based flipped learning platform for medical education

第11次中国实验血液学会议

作者： Won Kyung Jeon Sun Ok Park Bo Kyung Yoo Yeong Eun Kim Mi Young ke Sun Min Park Byoung-Seob Ko Department of Herbal Resources Research Korea Institute of Oriental MedicineDaejeon 305-811Korea Herbal Quality Control team Korea Institute of Oriental MedicineDaejeon 305-811Korea Herbal Quality Control team Korea Institute of Oriental MedicineDaejeon 305-811Korea Herbal Quality Control team Korea Institute of Oriental MedicineDaejeon 305-811Korea Herbal Quality Control team Korea Institute of Oriental MedicineDaejeon 305-811Korea Department of Food and Nutrition Hoseo UniversityAsanChubgnam 336-795Korea Herbal Quality Control team Korea Institute of Oriental MedicineDaejeon 305-811Korea

＜正＞For a correlation to study the Five Tastes Theory and efficacies in oriental medicine concepts,we used a traditional classified bitter taste herbal medicines and experimental *** this study,we have tested the in vitro effect of typical 20 kinds of herbal medicines with hitter taste on platelet aggregation in- duced by collagen in human whole blood using the impedance method of *** them,3 kinds of hot water extracts and 2 kinds of 70% etha-

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Digital Communications and Networks 2017年第3期3卷 188-194页

作者： Maqbool Ali Hafiz Syed Muhammad Bilal Muhammad Asif Razzaq Jawad Khan Sungyoung Lee Muhammad Idris Mohammad Aazam Taebong Choi Soyeon Caren Han Byeong Ho Kang Department of Computer Science and Engineering Kyung Hee University Yongin 446-701 Republic of Korea IT4BI Universite Libre de Bruxelles Belgium Carleton University Canada Hanwha Systems as Senior Manager Communication PM Team Seongnam 13524 Republic of Korea School of Engineering and ICT Uniuersity of Tasmania Hobart Tasmania 7005 Australia

Case-Based Learning (CBL) has become an effective pedagogy for student-centered learning in medical education, which is founded on persistent patient cases. Flippped learning and Internet of Things (IoTs) concepts have gained significant attention in recent years. Using these concepts in conjunction with CBL can improve learning ability by providing real evolutionary medical cases. It also enables students to build confidence in their decision making, and efficiently enhances teamwork in the learing environment. We propose an IoT-based Flip Learning Platform, called IoTFLiP, where an IoT infrastructure is exploited to support flipped case-based learning in a cloud environment with state of the art security and privacy measures for personalized medical data. It also provides support for application delivery in private, public, and hybrid approaches. The proposed platform is an extension of our Interactive Case-Based Flipped Learning Tool (ICBFLT), which has been developed based on current CBL practices. ICBFLT formulates summaries of CBL cases through synergy between students' and medical expert knowledge. The low cost and reduced size of sensor device, support of IoTs, and recent flipped learning advancements can enhance medical students' academic and practical experiences. In order to demonstrate a working scenario for the proposed IoTFLiP platform, real-time data from IoTs gadgets is collected to generate a real-world case for a medical student using ICBFLT.

关键词： Internet of things Cloud environment Flipped learning Case-based learning Medical education