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Holographic optical beam combining, splitting and cross-coupling: Numerical analysis and experimental investigation

Journal of Holography and Speckle 2009年第2期5卷 197-209页

作者： Yum, H.N. Hemmer, P.R. RenuTripathi Shahriar, M.S. Department of Electrical Engineering Texas A and M University College Station TX 77843 United States Department of Physics and Pre-Engineering Center for Research and Education in Optical Sciences and Applications Delaware State University Dover DE 19901 United States Department of Electrical Engineering and Computer Science Northwestern University Evanston IL 60208 United States

In this paper, we present the coupled-wave analysis for multiple thick holographic gratings for optical beam combining. Starting with the basic model of incoherently superimposed multiple gratings used to form the beam-combiner, we derive equations that describe wave propagation in a holographic substrate containing angular multiplexed gratings with either sinusoidal refractive index or absorption modulation including the off-Bragg matched condition. Numerical results are presented for multiple thick holographic gratings in three different geometries: the beam-splitter mode, the beam-combiner mode, and the cross-coupled mode. The effect of non-equal beam intensities and phased angle variation on the efficiency of beam combiner have been investigated. Experiment is performed to create an efficient six beam splitter-combiner using a thick photopolymer based holographic material. The experimental measurement for efficiency in beam combining compares well with the predicted value from our theoretical model. Copyright © 2009 American Scientific Publishers All rights reserved.

关键词： Efficiency

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Team AnnieWAY's autonomous system for the DARPA Urban Challenge 2007

Team AnnieWAY's autonomous system for the DARPA Urban Challe...

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作者： Kammel, Sören Ziegler, Julius Pitzer, Benjamin Werling, Moritz Gindele, Tobias Jagzent, Daniel Schöder, Joachim Thuy, Michael Goebl, Matthias Von Hundelshausen, Felix Pink, Oliver Frese, Christian Stiller, Christoph Institute for Measurement and Control University of Karlsruhe Karlsruhe 76131 Germany Institute for Applied Computer Science/Automation University of Karlsruhe Karlsruhe 76128 Germany Industrial Applications of Informatics and Microsystems University of Karlsruhe Karlsruhe 76131 Germany Institute for Distributed Measurement Systems Technical University of Munich Munich 80290 Germany Institute for Institute for Real-Time Computer Systems Technical University of Munich Munich 80290 Germany Department of Aerospace Engineering University of the Federal Armed Forces Neubiberg 85577 Germany

ISBN: (纸本)9783642039904

This paper reports on AnnieWAY, an autonomous vehicle that is capable of driving through urban scenarios and that has successfully entered the finals of the 2007 DARPA Urban Challenge competition. After describing the main challenges imposed and the major hardware components, we outline the underlying software structure and focus on selected algorithms. Environmental perception mainly relies on a recent laser scanner which delivers both range and reflectivity measurements. While range measurements are used to provide 3D scene geometry, measuring reflectivity allows for robust lane marker detection. Mission and maneuver planning is conducted using a concurrent hierarchical state machine that generates behavior in accordance with California traffic laws. We conclude with a report of the results achieved during the competition. © 2009 Springer-Verlag Berlin Heidelberg.

关键词： Reflection

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Virtual Worlds as a Tool for Enterprise Services

Virtual Worlds as a Tool for Enterprise Services

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Consumer Communications and Networking Conference, CCNC IEEE

作者： Sameer Vijaykar Muthukkumar S. Kadavasal Krishna K. Dhara Xiaotao Wu Venkatesh Krishnaswamy Department of Computer Science and Engineering Indian Institute of Technology Mumbai India Virtual Reality Applications Center Iowa State University Ames IA USA Avaya Laboratories Research Lincroft NJ USA

Online virtual worlds offer exciting new opportunities for enterprises or businesses. To exploit these opportunities enterprises need to find a way to integrate virtual world services with their real-world services, and to exploit virtual worlds rich collaboration environment to offer new or enhanced services. However, there are many challenges to realizing these goals, such as resolving virtual and real identifications, controlling communication sessions between real and virtual world entities, and managing resources in both worlds. In this paper, we study these issues and propose a framework for integrating virtual worlds into enterprise service work flow. We implemented a customer service in a VW contact center that is integrated with corresponding enterprise services. We also present a novel mechanism in virtual worlds that allow users to bring their own resources, along with the contact center resources, and share the resources with other customers or agents to resolve customer issues. Further, we present experiences from our prototype.

关键词： Virtual reality Data processing Sensor systems Data mining Laboratories Sensor systems and applications Hardware Virtual environment Noise measurement Time measurement

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Hand posture recognition using Hidden Conditional Random Fields

Hand posture recognition using Hidden Conditional Random Fie...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： Te-Cheng Liu Ko-Chih Wang Augustine Tsai Chieh-Chih Wang Department of Computer Science and Information Engineering National Taiwan University Taipei Taiwan Graduate Institute of Networking and Multimedia National Taiwan University Taipei Taiwan Institute for Information Industry Innovative Digitech-Enabled Applications and Services Institute Taipei Taiwan Department of Computer Science and Information Engineering and the Graduate Institute of Networking and Multimedia National Taiwan University Taipei Taiwan

Body-language understanding is essential to human robot interaction, and hand posture recognition is one of the most important components in a body-language recognition system. The existing hand posture recognition approaches based on robust local features such as SIFT can be invariant to background noise and in-plane rotation. However the ignorance of the relationships among local features is a fundamental issue. The part-based models argue that objects of the same category share the same part-structure which consists of parts and relationships among parts. In this paper, a discriminative part-based model, hidden conditional random fields (HCRFs), is used to recognize hand postures. Although the existing global locations of features have been used to consider large scale dependency among parts in the HCRFs framework, the results are not invariant to in-plane rotation. New features by the distance to the image center are proposed to encode the global relationship as well as to perform in-plane rotation-invariant recognition. The experimental results demonstrate that the proposed approach is in-plane rotation-invariant and outperforms the approach using AdaBoost with SIFT.

关键词： Face detection Detectors Human robot interaction Face recognition Background noise Image recognition Cameras Noise robustness Large-scale systems Skin

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A Framework for Personalized Health Trend Analysis

A Framework for Personalized Health Trend Analysis

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International Symposium on Parallel Architectures, Algorithms and Networks (ISPAN)

作者： Guo-Cheng Lan Chao-Hui Lee Jin-Shang Wu Huan-Chung Li Shing-Hua Ho Vincent S. Tseng Department of Computer Science and Information Engineering National Cheng Kung University Tainan County Taiwan Department of Family Medicine National Cheng Kung University Tainan County Taiwan Institute for Information Industry Innovative Digitech-Enabled Applications and Services Institute Taipei Taiwan Institute for Information Industry Innovative Digitech-Enabled Applications and Services Institute Kaohsiung Taiwan Institute of Computer Science and Information Engineering and Institute of Medical Informatics National Cheng Kung University Tainan County Taiwan

In recent years, with the development of the economy and the advancement of the national income, personal healthcare has been becoming an important issue. Since the health examination can help people understand their own health conditions clearly, many people make regularly health examinations to avoid missing the best treatment time. So the health examination is an important role for people's health statuses. However, people only get aware of the result of health examination report but they are not clear whether their health trends are high-risk or not. In this paper, we proposed a novel framework for discovering health risk patterns and the relationships between the patterns and a target disease by mining historic health examination data. Moreover, a prediction model for the target disease can be constructed effectively by the discovered information. Through the framework, the physicians can early provide health alerts and medical treatments for people to effectively increase the quality of disease prevention.

关键词： Cardiac disease Data mining Cardiovascular diseases Information analysis computer science Biomedical engineering Application software computer industry Medical services Predictive models

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High Aspect ratio metamaterials for enhanced tunability and sensitivity

High Aspect ratio metamaterials for enhanced tunability and ...

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Conference on Lasers and Electro-Optics, CLEO 2009

作者： Chiam, Sher-Yi Bahou, Mohammed Moser, Herbert O. Gu, Jianqiang Singh, Ranjan Zhang, Weili Han, Jiaguang Bettiol, Andrew A. Center for Ion Beam Applications Department of Physics National University of Singapore Singapore Singapore Synchrotron Light Source National University of Singapore 5 Research Link 117603 Singapore School of Electrical and Computer Engineering Oklahoma State University Stillwater OK 74078 United States Center for Terahertz waves and College of Precision Instrument and Optoelectronics Engineering Tianjin University The Ministry of Education The Key Laboratory of Opto-electronics Information and Technical Science Tianjin 300072 China

Using a proton beam based lithography process, we fabricate and study high aspect ratio metamaterials, revealing distinct 3-dimensional resonances. Increased aspect ratio also leads to enhanced tunability and sensitiv... 详细信息

ISBN: (纸本)9781557528698

关键词： Metamaterials

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Stent graft change detection after endovascular abdominal aortic aneurysm repair

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10th International Conference on Intelligent Data engineering and Automated Learning, IDEAL 2009

作者： Maiora, Josu García, Guillermo Tapia, Arantxa MacÍa, Iván Legarreta, Jon Haitz Paloc, Céline Graña, Manuel De Blas, Mariano Electronics and Telecomunications Department Technical University School University of the Basque Country Donostia-San Sebastián Spain Engineering Systems and Automatic Department Technical University School University of the Basque Country Donostia-San Sebastián Spain Biomedical Applications Department VICOMTech Donostia-San Sebastián Spain Computational Intelligence Group Computer Science Faculty University of the Basque Country Donostia-SanSebastián Spain Interventional Radiology Service Donostia Hospital Donostia-SanSebastián Spain

ISBN: (纸本)3642043933

The use of the endovascular prostheses in Abdominal Aortic Aneurysm (EVAR) has proven to be an effective technique to reduce the pressure and rupture risk of aneurysm. Nevertheless, in a long term perspective different complications such as prostheses displacement or leaks inside the aneurysm sac (endoleaks) could appear causing a pressure elevation and increasing the danger of rupture consequently. At present computed tomographic angiography (CTA) is the most commonly used examination for imaging surveillance for stent graft monitoring. However, endoleak complications can not always be detected by visual inspection on CTA scans. The purpose of this work was to study the application of image registration techniques to the detection of changes in the stent graft. Previously we segment the lumen using semi-automatic methods. © 2009 Springer Berlin Heidelberg.

关键词： Stents

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Scaling Genetic Algorithms Using MapReduce

Scaling Genetic Algorithms Using MapReduce

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International Conference on Intelligent Systems Design and applications (ISDA)

作者： Abhishek Verma Xavier Llorà David E. Goldberg Roy H. Campbell Department of Computer Science University of Illinois Urbana-Champaign IL USA National Center for Supercomputing Applications (NCSA) University of Illinois Urbana-Champaign IL USA Department of Industrial and Enterprise Systems Engineering University of Illinois Urbana-Champaign IL USA

Genetic algorithms (GAs) are increasingly being applied to large scale problems. The traditional MPI-based parallel GAs require detailed knowledge about machine architecture. On the other hand, MapReduce is a powerful abstraction proposed by Google for making scalable and fault tolerant applications. In this paper, we show how genetic algorithms can be modeled into the MapReduce model. We describe the algorithm design and implementation of GAs on Hadoop, an open source implementation of MapReduce. Our experiments demonstrate the convergence and scalability up to 10 5 variable problems. Adding more resources would enable us to solve even larger problems without any changes in the algorithms and implementation since we do not introduce any performance bottlenecks.

关键词： Genetic algorithms Large-scale systems Scalability Application software Fault tolerance Concurrent computing Evolutionary computation Intelligent systems computer science computer industry

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Computing the Casimir energy using the point-matching method

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Physical Review D 2009年第6期80卷 065018-065018页

作者： F. C. Lombardo F. D. Mazzitelli M. Vázquez P. I. Villar Departamento de Física Juan José Giambiagi FCEyN University of Buenos Aires Facultad de Ciencias Exactas y Naturales Ciudad Universitaria Pabellón I 1428 Buenos Aires Argentina Computer Applications on Science and Engineering Department Barcelona Supercomputing Center (BSC) 29 Jordi Girona 08034 Barcelona Spain

We use a point-matching approach to numerically compute the Casimir interaction energy for a two perfect-conductor waveguide of arbitrary section. We present the method and describe the procedure used to obtain the numerical results. At first, our technique is tested for geometries with known solutions, such as concentric and eccentric cylinders. Then, we apply the point-matching technique to compute the Casimir interaction energy for new geometries such as concentric corrugated cylinders and cylinders inside conductors with focal lines.

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C-band scatterometer measurements of multiyear sea ice before fall freeze-up in the Canadian arctic

C-band scatterometer measurements of multiyear sea ice befor...

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作者： Isleifson, Dustin Langlois, Alexandre Barber, David G. Shafai, Lotfollah Department of Electrical and Computer Engineering University of Manitoba Winnipeg MB R3T 5V6 Canada Centre d'Applications et de Recherches en Télédection Département de Géomatique Appliquée Université de Sherbrooke Sherbrooke QC J1K 2R1 Canada Centre for Earth Observation Science Faculty of Enviroment University of Manitoba Winnipeg MB R3T 2N2 Canada

Backscatter signatures of multiyear sea ice (MYI) during the late summer and early fall season before the fall freeze-up in the Canadian Arctic Archipelago (CAA) have been obtained through the use of a ship-based polarimetric scatterom-eter. The device operates in C-band, and measurements were conducted in swaths from incidence angles of 20-60. Three characteristic sites on MYI floes were investigated in the high Arctic and the central Arctic regions. In situ snow and sea-ice thermophysical data were collected at each site in conjunction with local scatterometer measurements. The thermophysical data were subsequently analyzed using dielectric modeling techniques and coupled with the backscattering measurements (

关键词： Sea ice

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