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Unidirectional phase singularity in ultrathin metamaterials at exceptional points

Physical Review A 2014年第6期89卷 065801-065801页

作者： Ming Kang Hai-Xu Cui Teng-Fei Li Jing Chen Weiren Zhu Malin Premaratne College of Physics and Materials Science Tianjin Normal University Tianjin 300387 China MOE Key Laboratory of Weak-Light Nonlinear Photonics School of Physics Nankai University Tianjin 300071 China Advanced Computing and Simulation Laboratory (AχL) Department of Electrical and Computer Systems Engineering Monash University Clayton Victoria 3800 Australia

Scattering properties of light in metamaterials are similar to those in open quantum systems. Here we propose an ultrathin tailored metamaterial designed to show that one-way zero reflection yielding to topologically stable phase dislocation is responsible for the exceptional point, one of the most important degeneracies in the non-Hermitian Hamiltonian. In order to bridge the exotic macroscopic optical phenomenon occurring in metamaterials, a phenomenological model under microscopic view is developed and good agreement with the full-blown numerical simulation is found. Our investigation uncovers the capabilities of metamaterials to exhibit extreme optical properties and to provide us with many potential applications such as the suppression of undesired scattering signals in the spectral band ranging from microwaves to visible light.

关键词： QUANTUM phase transitions LIGHT -- Scattering TOPOLOGY METAMATERIALS PHENOMENOLOGICAL theory (Physics) MICROWAVES

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Investigation of Mechanical Properties, Microstructure and Wear Rate of High Leaded Tin Bronze after Multidirectional Forging

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Procedia Materials Science 2014年 5卷 1081-1089页

作者： Rahul Gupta Sanjay Srivastava G.V. Preetham Kumar Sanjay K. Panthi Ph.D Research Scholar Department of Material Science & Metallurgical Engineering Maulana Azad National Institute of Technology Bhopal 462003 India Associate Professor Department of Material Science & Metallurgical Engineering Maulana Azad National Institute of Technology Bhopal 462003 India Assistant Professor Department of Metallurgical & Materials Engineering National Institute of Technology Karnataka Surathkal Mangalore 575025 India Scientist Computer Simulation & Design Center Advanced Materials and Processes Research Institute (AMPRI) Near Habibganj Naka Hoshangabad Road Bhopal 462064 India

In this work, the change in mechanical properties, microstructure and wear rate of high leaded tin bronze material was studied after multidirectional forging (MDF) process. The total equivalent strain of 0.75 was applied during MDF process result in the improvement of ultimate tensile strength, yield strength, hardness and wear rate along with maintained ductility with the increase in the number of MDF pass. The initial average grain size of 120 nm was refined to the final grain size of 37 nm. The transmission electron microscope, scanning electron microscope and optical microscope was used for the microstructure study of the undeformed, MDForged and wear worn surfaces.

关键词： Multidirectional forging high leaded tin bronze mechanical properties microstructure wear

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Power-optimized stiffness and nonlinear position control of an actuator with Variable Torsion Stiffness

Power-optimized stiffness and nonlinear position control of ...

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2013 IEEE/ASME International Conference on Advanced Intelligent Mechatronics: Mechatronics for Human Wellbeing, AIM 2013

作者： Beckerle, P. Wojtusch, J. Schuy, J. Strah, B. Rinderknecht, S. Stryk, O.V. Institute for Mechatronic Systems Department of Mechanical Engineering Technische Universität Darmstadt Darmstadt Germany Simulation Systems Optimization and Robotics Group Department of Computer Science Technische Universität Darmstadt Darmstadt Germany

ISBN: (纸本)9781467353199

Introducing compliant actuation to robotic joints is an approach to ensure safety in closer human-machine interaction. Further, the possibility to adjust stiffness can be benificial considering energy storage and the power consumption required to track certain trajectories. The subject of this paper is the stiffness and position control of the Variable Torsion Stiffness (VTS) actuator for application in compliant robotic joints. For the realization of a variable rotational stiffness, the active length of a torsional elastic element in serial configuration between drive and link is adjusted in VTS. After the deduction of an extended drive train model, this paper gives an advanced power analysis clarifying power-optimal settings from previous basic models and identifying additional settings that allow for a more versatile operation. Based on these results that can be generalized to other variable elastic actuator concepts, an optimized strategy for setting stiffness is determined considering the whole system dynamics including natural frequencies as well as antiresonance effects. For position control of VTS in a prototypical implementation, a nonlinear position controller is designed by means of feedback linearization. Although the system is modified significantly by changing drive train stiffness, the stiffness adaptation of the controller ensures the required tracking performance. © 2013 IEEE.

关键词： Stiffness

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Analysis and compensation of radial motion effect on stepped frequency signal

Analysis and compensation of radial motion effect on stepped...

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2nd International Conference on Mechanical engineering, Industrial Electronics and Informatization, MEIEI 2013

作者： Zhang, Yao Tian Liu, Jia Jia Zhang, Yu Xian Liu, Miao Department of Electrical Engineering Beihang University Beijing 100191 China Automatic Control and Computer Simulation Liaoning 125001 China 142 mail boxes on the 1st 205 points Beijing 100854 China

ISBN: (纸本)9783037858905

Stepped frequency signal is an important high distance resolution signal, this property is realized by combining several pulse signal, so it is easy to be effected by target's radial motion. Here we analyzed how target's radial motion affects the synthesis HRRP, then a method of velocity measurement is provided, then compensation using the predicted velocity. © (2013) Trans Tech Publications, Switzerland.

关键词： Motion compensation

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Service oriented movie-based programming environment

Service oriented movie-based programming environment

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IEEE International Conference on Intelligent Software Methodologies, Tools and Techniques (SoMeT)

作者： Ruth Cortez Hayato Tan Alexander Vazhenin Dmitry Vazhenin Department of Computer Science and Engineering University of Aizu Fukushima Japan Simulation Corporation Yokohama Japan

ISBN: (纸本)9781479904181

Movie-based (MB) programming environment is a visual programming platform for creating algorithms and programs applying animation frames with computational and sensible operations. It facilitates the user's understanding and debugging of a program by coloring correlated areas of structures, introducing appropriate computational formulas as well as specifying algorithmic and logical behavior of those areas. The goal of the presented work is adapting the current system to Service-oriented Architecture in order to organize a sharable storage and server-based execution of MB-programs and algorithms. Therefore, the MB-programs/algorithms could be shared and reused by different developers. In this paper, features of MB-programming paradigm and the corresponding software are presented, which are used to enhance capabilities for data/knowledge and execution management. In the framework of Virtual-MVC design pattern, the MB-management architecture, component's design steps and a prototype of service-oriented MB-programming environment are discussed, including concepts and examples of usage.

关键词： Programming Visualization Programming environments Libraries Engines Heuristic algorithms Motion pictures

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Learning social calculus with genetic programing

Learning social calculus with genetic programing

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26th International Florida Artificial Intelligence Research Society Conference, FLAIRS 2013

作者： Khan, Saad Ahmad Streater, Jonathan Bhatia, Taranjeet Singh Fiore, Steve Bölöni, Ladislau Department of Electrical Engineering and Computer Science University of Central Florida Orlando FL 32816 United States Institute of Simulation and Training University of Central Florida 4000 Central Florida Blvd Orlando FL 32816 United States

ISBN: (纸本)9781577356059

Physical or simulated agents sharing an environment with humans must evaluate the impact of their own and other agents' actions in the specific social and cultural context. It is desirable that this social calculus aligns itself with the models developed in sociology and psychology - however, it needs to be expressed in an operational, algorithmic form, suitable for implementation. While we can develop the framework of social calculus based on psychological theories of human behavior, the actual form of the algorithms can only be acquired from the knowledge of the specific culture. In this paper we consider social calculus based on culture-sanctioned social values (CSSMs). A critical component of this model is the set of action-impact functions (AIFs), which describe how the actions of the agents change the CSSMs in specific settings. We describe a technique to evolve the AIFs using genetic programming based on a limited set of data pairs which can be obtained by surveying humans immersed in the specific culture. We describe the proposed model through a scenario involving a group of soldiers and a robot acting on a peacekeeping mission. Copyright © 2013, Association for the Advancement of Artificial Intelligence. All rights reserved.

关键词： Genetic programming

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ChronoLeap: The great world's fair adventure

ChronoLeap: The great world's fair adventure

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5th International Conference on Virtual, Augmented and Mixed Reality: Designing and Developing Augmented and Virtual Environments, VAMR 2013, Held as Part of 15th International Conference on Human-computer Interaction, HCI International 2013

作者： Walters, Lori C. Hughes, Darin E. Barrio, Manuel Gértrudix Hughes, Charles E. Institute for Simulation and Training University of Central Florida Orlando FL United States Faculty of Communication Universidad Rey Juan Carlos Madrid Spain Department of Electrical Engineering and Computer Science University of Central Florida Orlando FL United States

ISBN: (纸本)9783642394195

ChronoLeap: The Great World's Fair Adventure utilizes the educational potential of immersive 3D virtual venues for children and early adolescents between 9 and 13. Virtual reality environments transport the mind beyond the 2D bounds of text or photographs;they engage the imagination and can be a powerful tool for conveying educational content [1]. ChronoLeap leverages these innate qualities and weaves together the individual threads of single disciplines into a multi-disciplinary tapestry of web-based exploration through the 1964/65 New York World's Fair. Through their myriad of pavilions and exhibits, World Fairs offer links to science, technology, engineering, mathematics, art and humanities topics. ChronoLeap provides an immersive 3D environment with highly accurate and detailed models, and merges it with games and themes designed to provide users an educational STEAM environment. The project is a collaborative effort between the University of Central Florida, Queens Museum of Art and New York Hall of Science. © 2013 Springer-Verlag Berlin Heidelberg.

关键词： Virtual reality

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DNS and les of excited rectangular jets 8

DNS and les of excited rectangular jets

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8th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013

作者： Tyliszczak, Artur Geurts, Bernard J. Department of Mechanical Engineering and Computer Science Institute of Thermal Machinery Czestochowa University of Technology Al. Armii Krajowej 21 Czestochowa42-200 Poland Department of Applied Mathematics Multiscale Modeling and Simulation University of Twente P.O. Box 217 AE Enschede7500 Netherlands

The paper presents results of numerical studies devoted to an active flow control method applied to jet flow and focusses on rectangular jets with aspect ratio Ar = 1, 2 and 3. Square and rectangular jets are more unstable than their circular counterparts, which is expressed by an increased intensity of mixing. It is shown that the application of a suitable excitation (forcing) at the jet nozzle can qualitatively alter the character of the flow, resulting in an increased spreading rate of passive tracer. The excitation is obtained from a superposition of axial and helical forcing terms. We study the mixing in the flow upon varying parameters such as the frequency of the excitations and possible phase shifts between components. The numerical results are obtained applying LES and DNS based on a high-order compact difference code for the incompressible flows.

关键词： Aspect ratio

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Introducing tangible objects into motion controlled gameplay using Microsoft® Kinect™

Introducing tangible objects into motion controlled gameplay...

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作者： Bozgeyikli, Gamze Bozgeyikli, Evren Işler, Veysi Informatics Institute Middle East Technical University Ankara Turkey Game and Animation Technologies Research Laboratory Modeling and Simulation Research and Development Center Middle East Technical University Ankara Turkey Department of Computer Engineering Middle East Technical University Ankara Turkey

Improvements in ways of game controlling in recent years yielded higher level of interaction. Release of motion controller devices changed conventional ways of controlling games that have been used so far. Microsoft®;Kinect™ (Microsoft Corporation, WA, USA) recognizes motions of the players as game controlling inputs. Although touchless interaction is perceived to be attractive, games mimicking real life activities may benefit from hand-held tangible objects for the player to get more involved into game. In this study, a tangible gameplay interaction method is developed using Microsoft®;Kinect™ that senses hand-held objects with their dimensions and incorporates them into gameplay. Proposed algorithm is implemented on an experimental game, and a user study is performed to measure effects of tangible interaction on Kinect gameplay experience. Results revealed that an improved gameplay with more natural and accurate motion controlling is achieved. Copyright © 2013 John Wiley & Sons, Ltd.

关键词： Human computer interaction

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Mixed reality space travel for physics learning

Mixed reality space travel for physics learning

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作者： Hughes, Darin E. Sabbagh, Shabnam Lindgren, Robb Moshell, J. Michael Hughes, Charles E. Institute for Simulation and Training University of Central Florida Orlando FL United States School of Visual Arts and Design University of Central Florida Orlando FL United States Department of Electrical Engineering and Computer Science University of Central Florida Orlando FL United States

ISBN: (纸本)9783642394195

In this paper we describe research being conducted on a mixed reality simulation called MEteor that is designed for informal physics learning in science centers. MEteor is a 30 x 10 foot floor area where participants use their bodies to interact with projected astronomical imagery. Participants walk and run across the floor to simulate how objects move in space, and to enact basic physics principles. Key to the success of this learning environment is an interface scheme that supports the central metaphor of "child as asteroid." Using video data collected in our studies we examine the extent to which feedback mechanisms and interface conventions strengthened the metaphorical connection, and we describe ways the interaction design can be improved for future iterations. © 2013 Springer-Verlag Berlin Heidelberg.

关键词： Mixed reality

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