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作者： Nery, Alexandre S. Nedjah, Nadia França, Felipe M.G. LAM - Computer Architecture and Microeletronics Laboratory Systems Engineering and Computer Science Program COPPE Universidade Federal Do Rio de Janeiro Rio de Janeiro RJ Brazil Department of Electronics Engineering and Telecommunications Faculty of Engineering Universidade Do Estado Do Rio de Janeiro Rio de Janeiro RJ Brazil

Real time rendering of three-dimensional scenes in high photorealistic details is a hard task, such as in the ray tracing rendering algorithm. In general, the performance achieved by a sequential software-based implementation of ray tracing is far from satisfactory. However, parallel implementations of ray tracing have been enabling reasonable real time performance, as the algorithm is embarrassingly parallel. Thus, a custom parallel design in hardware is likely to achieve an even higher performance. In this paper, we propose a hardware parallel architecture capable of dealing with the main desirable features of ray tracing, such as shadows and reflection effects, imposing low area cost and a promising rendering performance. Such architecture, called GridRT, is based on the Uniform Grid acceleration structure and is intended to deliver massive parallelism through parallel ray-triangle intersection tests as well as parallel processing of many rays. A hardware implementation of the proposed architecture is presented, together with some performance results and resources requirements. The rendering is reduced by 80% using a grid configuration of eight processing elements. © Springer Science+Business Media, LLC 2011.

关键词： Field programmable gate arrays (FPGA)

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A sensor positioning algorithm for the EMMON large scale Wireless Sensor Network architecture

A sensor positioning algorithm for the EMMON large scale Wir...

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IEEE International Conference on Industrial Technology (ICIT)

作者： Theodoros Fronimos Loukas Petrou George Hassapis Department of Electrical and Computer Engineering Laboratory of Computer Systems Architecture Aristotle University of Thessaloniki Thessaloniki Greece Department of Electrical and Computer Engineering Aristotle University of Thessaloniki Thessaloniki Greece

In this paper a sensor positioning scheme is proposed for the EMMON architecture of Wireless Sensor Networks (WSN). This is a recently developed new multi - tiered hierarchical structure imposing the need for a distributed, low - complexity positioning algorithm. In this work we developed an integrated positioning scheme which involves an on-line calibration phase and a subsequent assessment of the parameters of a fuzzy inference system used to generate distance approximations based on RSSI values. In the calibration phase a sensor node is placed arbitrarily in a number of known positions and collects RSSI measurements from all anchor nodes. A data set consisting of RSSI values vs. distance is created and is used as training data set of the fuzzy inference system. Finally experimental results are presented which show the improvement achieved in the accuracy of the proposed scheme against other range-based schemes.

关键词： Wireless sensor networks computer architecture Internet Protocols Estimation Position measurement

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Combining gait research of the quadruped/biped reconfigurable walking chair with parallel leg mechanism

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4th International Conference on Social Robotics, ICSR 2012

作者： Hu, Xing Wang, Hongbo Sang, Lingfeng Gu, Qifang Yuan, Lin School of Mechanical and Electrical Engineering Xi'an University of Architecture and Technology Xi'an Shanxi 710055 China Ministry of Education Key Laboratory of Advanced Forging Technology and Science Hebei Province Key Laboratory of Parallel Robot and Mechatronics Systems Yanshan University Qinhuangdao Hebei 066004 China Department of Computer Wuxi City College of Vocational Technology Wuxi 214063 China

ISBN: (纸本)9783642341021

The quadruped/biped reconfigurable walking robot with parallel leg mechanism can realize not only the quadruped walking, but also the biped walking. The converting process from the quadruped to the biped includes locking the vertical revolute pair hinged with the upper platform and combining the corresponding lower platforms. Based on the previous study, the combining schemes of walking chair are researched in this paper, and then the correctness of the combining schemes is analyzed by using the position workspace of the swing leg and the body mechanism in different states which are obtained by the MATLAB software and anti-solution search method. Compared with the stability margin and the adjustment coordination of the body in the different combining schemes, the optimal combining gaits of walking chair are selected, which lays the theoretical foundation for the quadruped/biped converting control of walking chair. © 2012 Springer-Verlag.

关键词： MATLAB

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A multi-lead ECG classification based on random projection features

A multi-lead ECG classification based on random projection f...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Iva Bogdanova Francisco Rincón David Atienza Embedded Systems Laboratory (ESL) Ecole Polytechnique Fédérale de Lausanne Switzerland Department of Computer Architecture and Automation Complutense University of Madrid Spain

This paper presents a novel method for classification of multi-lead electrocardiogram (ECG) signals. The feature extraction is based on the random projection (RP) concept for dimensionality reduction. Furthermore, the classification is performed by a neuro-fuzzy classifier. Such a model can be easily implemented on portable systems for practical applications in both health monitoring and diagnostic purposes. Moreover, the RP implementation on portable systems is very challenging featuring both energy efficiency and feasibility. The proposed method is tested on a 12-lead ECG database consisting of 20 beats during normal sinus rhythm, 20 beats with myocardial infarction and 20 beats showing cardiomyopathy for 60 different subjects. The experiments give a recognition rate of 100% for a small number of RP coefficients (only 25), i.e. after a considerable dimensionality reduction of the input ECG signal. The results are very promising, not only from the classification performance point of view, but also while targeting a low-complexity feature extraction in terms of computation requirements and memory usage for real-time operation on a wireless wearable sensor platform.

关键词： Electrocardiography Feature extraction Databases Pragmatics Wireless sensor networks Wireless communication computer architecture

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A generic agent-oriented model used fordesigning a collaborative information system

A generic agent-oriented model used fordesigning a collabora...

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World Conference on Complex systems (WCCS)

作者： Sara Maalal Malika Addou Wafaa Dachry Brahim Aghezzaf Team of Systems'Architecture Laboratory of computing Systems and Renewable Energy National and High School of Electricity and Mechanic Casablanca Morocco Department of Mathematics and Computer Faculty of sciences Hassan II University Casablanca Morocco

Faced with new environmental constraints, firms decide to collaborate in collective entities and adopt new patterns of behavior. So, this firms' collaboration becomes an unavoidable approach. This collaboration can be represented by many agents collaboration within a multi agent system. Indeed, agent technology is a software paradigm that permits to implement large and complex distributed applications [1]. In order to assist analyzing, conception and development or implementation phases of multi-agent systems, we've tried to present a practical application of a generic and scalable method of a MAS with a component-oriented architecture and agent-based approach that allows MDA to generate source code from a given model. We have designed a generic class diagram as a class meta-model of different agents of a MAS. Then we have applied it on a collaborative platform based on MAS supply chain which ensures cooperation and information logging and sharing between partners in real time. We have finally generated the model source code developed using an open source tool called AndroMDA. This agent-based and evolutive approach enhances the modularity and genericity developments and promotes their reusability in future developments.

关键词： Unified modeling language Collaboration Object oriented modeling Multiagent systems Computational modeling Software Complexity theory

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Delay-bounded Sink Mobility in Wireless Sensor Networks

Delay-bounded Sink Mobility in Wireless Sensor Networks

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IEEE International Conference on Communications

作者： Yu Gu Yusheng Ji Jie Li Biao Han Baohua Zhao Information Systems Architecture Science Research Division National Institute of Informatics Department of Computer Science University of Tsukuba Tsukuba Science City State Key Laboratory of Networking and Switching Technology

ISBN: (纸本)9781457720529

This paper exploits sink mobility to prolong the network lifetime in wireless sensor networks (WSNs) where the information delay caused by moving the sink should be bounded. We build a unified framework for analyzing this joint sink mobility and routing problem. We offer a mathematical modeling that is general and captures diversified issues, e.g. sink mobility, routing, delay, etc. We discuss the induced subproblems and present efficient solutions for them. Then, we generalize these solutions and propose a polynomial-time optimal algorithm for the origin problem. In simulations, we show the benefits of involving a mobile sink. We also show that the impact of the delay bound on the network lifetime.

关键词： Sinks Wireless sensor networks Routing Problem mobility mathematical modeling

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Design and Performance Issues of Cholesky and LU Solvers Using UPCBLAS

Design and Performance Issues of Cholesky and LU Solvers Usi...

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International Symposium on Parallel and Distributed Processing with Applications, ISPA

作者： Jorge Gonz'lez-Domínguez Osni A. Marques María J. Martín Guillermo L. Taboada Juan Touriño Universidade da Coruna A Coruna Galicia ES Computational Research Division Lawrence Berkeley National Laboratory CA USA Computer Architecture Group Department of Electronics and Systems University of A Coruña Spain

Partitioned Global Address Space (PGAS) languages offer programmers a shared memory view that increases their productivity and allow locality exploitation to obtain good performance on current large-scale distributed memory systems. UPCBLAS is a parallel numerical library for dense matrix computations using the PGAS Unified Parallel C (UPC) language. The interface of this library exploits the characteristics of the PGAS memory model and thus it is easier to use than MPI-based libraries. This paper addresses the implementation of solvers of systems of equations through Cholesky and LU factorizations in UPC using UPCBLAS. The developed codes are experimentally evaluated and compared to the MPI versions using ScaLAPACK. Parallel solvers of equations are present in many parallel numerical applications and they have been traditionally developed in MPI. This work shows that UPCBLAS can be considered as a good alternative to the MPI-based libraries for increasing the productivity of numerical application developers.

关键词： Libraries Message systems Instruction sets Electronics packaging Equations Vectors Arrays

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Fault mitigation schemes for future spaceflight multicore processors

Fault mitigation schemes for future spaceflight multicore pr...

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AIAA Infotech at Aerospace Conference and Exhibit 2012

作者： Alexander, James W. Clement, Bradley J. Gostelow, Kim P. Lai, John Y. Jet Propulsion Laboratory California Institute of Technology GN and C Hardware and Testbed Development Group 4800 Oak Grove Drive MS 198-235 Pasadena CA 91109 United States Jet Propulsion Laboratory California Institute of Technology Cyber Defense and Information Architecture Group 4800 Oak Grove Drive MS 301-285 Pasadena CA 91109 United States Jet Propulsion Laboratory California Institute of Technology Advanced Computer Systems and Technologies Group 4800 Oak Grove Drive MS 321-151 Pasadena CA 91109 United States

ISBN: (数字)9781600869396

ISBN: (纸本)9781600869396

Future planetary exploration missions demand significant advances in on-board computing capabilities over current avionics architectures based on a single-core processing element. The state-of-the-art multi-core processor provides much promise in meeting such challenges while introducing new fault tolerance problems when applied to space missions. Software-based schemes are being presented in this paper that can achieve system-level fault mitigation beyond that provided by radiation-hard-by-design (RHBD). For mission and time critical applications such as the Terrain Relative Navigation (TRN) for planetary or small body navigation, and landing, a range of fault tolerance methods can be adapted by the application. The software methods being investigated include Error Correction Code (ECC) for data packet routing between cores, virtual network routing, Triple Modular Redundancy (TMR), and Algorithm-Based Fault Tolerance (ABFT). A robust fault tolerance framework that provides fail-operational behavior under hard real-time constraints and graceful degradation will be demonstrated using TRN executing on a commercial Tilera® processor with simulated fault injections. © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

关键词： Fault tolerance

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BOFAR: Buffer occupancy factor based adaptive router for mesh NoCs

BOFAR: Buffer occupancy factor based adaptive router for mes...

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4th International Workshop on Network on Chip architectures, NoCArc 2011, in Conjunction with the 44th Annual IEEE/ACM International Symposium on Microarchitecture, MICRO44

作者： Jose, John Shankar, J. Shiva Mahathi, K.V. Kumar, Damarla Kranthi Mutyam, Madhu Computer Architecture and Systems Laboratory Department of Computer Science and Engineering Indian Institute of Technology Madras Chennai-36 India

ISBN: (纸本)9781450309479

If the route computation operation in an adaptive router returns more than one output channels, the selection strategy chooses one from them based on the congestion metric used. The effectiveness of a selection strategy depends on what metric is used to identify congestion and how precisely that metric captures the actual congestion. The number of cycles a flit stays in a router is a direct indication of the contention level of the output port it desires to move out. We propose buffer Occupancy Factor based Adaptive Router (BOFAR), wherein the history of cycles spent by flits in buffers is used as the congestion metric. BOFAR outperforms the baseline architectures built on minimal odd-even adaptive router model with conventional selection strategies like count of free downstream virtual channels at reachable neighbors, and fluidity of buffers in downstream neighbors. Our experiments on 4x4 mesh NoC with various synthetic traffic patterns show that BOFAR exceeds the performance of best baseline adaptive router with 21% average and 78% maximum latency reduction at saturation load. The reduced average packet latency, increased buffer fluidity fairness, and increased saturation point of BOFAR with minimal overhead in area, power, and wiring makes it a promising alternative to existing adaptive routers in mesh NoCs. © 2011 ACM.

关键词： Network-on-chip

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Theoretical Treatment of Target Coverage in Wireless Sensor Networks

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Journal of computer Science & Technology 2011年第1期26卷 117-129页

作者：谷雨赵保华计宇生李颉 School of Computer Science University of Science and Technology of China State Key Laboratory of Networking and Switching Technology Information Systems Architecture Science Research Division National Institute of InformaticsTokyoJapan Department of Computer Science University of TsukubaTsukuba Science CityIbarakiJapan

The target coverage is an important yet challenging problem in wireless sensor networks, especially when both coverage and energy constraints should be taken into account. Due to its nonlinear nature, previous studies of this problem have mainly focused on heuristic algorithms; the theoretical bound remains unknown. Moreover, the most popular method used in the previous literature, i.e., discretization of continuous time, has yet to be justified. This paper fills in these gaps with two theoretical results. The first one is a formal justification for the method. We use a simple example to illustrate the procedure of transforming a solution in time domain into a corresponding solution in the pattern domain with the same network lifetime and obtain two key observations. After that, we formally prove these two observations and use them as the basis to justify the method. The second result is an algorithm that can guarantee the network lifetime to be at least （1 - ε） of the optimal network lifetime, where ε can be made arbitrarily small depending on the required precision. The algorithm is based on the column generation （CG） theory, which decomposes the original problem into two sub-problems and iteratively solves them in a way that approaches the optimal solution. Moreover, we developed several constructive approaches to further optimize the algorithm. Numerical results verify the efficiency of our CG-based algorithm.

关键词： target coverage wireless sensor networks time-dependent solution pattern-based solution column generation

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