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CIE International Conference on Radar (RADAR)

作者： Yang, Minglei Wang, Jing Chen, Baixiao Wang, Yi Xidian Univ Natl Lab Radar Signal Proc Xian Peoples R China

ISBN: (纸本)9781509048281

To solve the shortcomings of the Very High Frequency (VHF) radar, such as wide beam-width, low angular resolution and weak transportability, we propose a novel distributed VHF radar which consists of two identical VHF digital array radars. The system scheme of the experimental system and the main functions of the subsystems are given in this paper. We also design the signal processing method for the real data of the distributed VHF radar. The results of the real data show that the beam width of the distributed array is much narrower than that of the sub-arrays. And the accuracy of the angle estimation is around 1/10 that of the sub-arrays. Therefore, the proposed system can reach a high angle estimation accuracy with a relatively low cost and high transportability.

关键词： distributed array distributed aperture coherence-synthesizing radar Digital array module Experimental system Angle estimation

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Empirical Comparison of Three Versioning Architectures

Empirical Comparison of Three Versioning Architectures

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IEEE International Conference on Cluster Computing (CLUSTER)

作者： Fujita, Hajime Iskra, Kamil Balaji, Pavan Chien, Andrew A. Univ Chicago Dept Comp Sci 1100 East 58th St Chicago IL 60637 USA Argonne Natl Lab Math & Comp Sci Div Argonne IL 60439 USA

ISBN: (纸本)9781467365987

Future supercomputer systems will face serious reliability challenges. Among failure scenarios, latent errors are some of the most serious and concerning. Preserving multiple versions of critical data is a promising approach to deal with such errors. We are developing the Global View Resilience (GVR) library, with multi-version global arrays as one of the key features. This paper presents three array versioning architectures: flat array, flat array with change tracking, and log-structured array. We use a synthetic workload comparing the three array architectures in terms of runtime performance and memory requirements. The experiments show that the flat array with change tracking is the best architecture in terms of runtime performance, for versioning frequencies of 10(-5) ops(-1) or higher matching the second best architecture or beating it by over 8 times, whereas the log-structured array is preferable for low memory usage, since it saves up to 88% of memory compared with a flat array.

关键词： software architecture software libraries software reliability GVR library global view resilience library supercomputer system reliability three array versioning architecture arrays Benchmark testing Libraries Memory management Resilience Runtime Global View Resilience change tracking distributed array log-based data structures multi-versioning Benchmark testing Software libraries Store management Runtime Software reliability Software architecture arrays Resilience Libraries runtime performance ARCHITECTURE FLAT

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Versioning Architectures for Local and Global Memory 21

Versioning Architectures for Local and Global Memory

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21st IEEE International Conference on Parallel and distributed Systems ICPADS

作者： Fujita, Hajime Iskra, Kamil Balaji, Pavan Chien, Andrew A. Intel Corp Santa Clara CA 95051 USA Univ Chicago Chicago IL 60637 USA Argonne Natl Lab Argonne IL 60439 USA

ISBN: (纸本)9780769557854

Future supercomputer systems will face serious reliability challenges. Among failure scenarios, latent errors are some of the most serious and concerning. Preserving multiple versions of critical data is a promising approach to deal with such errors. We are developing the Global View Resilience (GVR) library, with multi-version global arrays as one of the key features. This paper presents three array versioning architectures: flat array, flat array with change tracking, and log-structured array. We use a synthetic workload that mimics the memory access patterns of radix sort, N-body simulation, and matrix multiplication, comparing the three array architectures in terms of runtime performance, memory requirements, and version restoration costs. The experiments show that the flat array with change tracking is the best architecture in terms of runtime performance, for versioning frequencies of 10 (5) ops (1) or higher matching the second best architecture or beating it by up to 23 times, whereas the log-structured array is preferable for low memory usage, since it saves up to 98% of memory compared with a flat array.

关键词： Global View Resilience multi-versioning distributed array change tracking log-based data structures

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PATH UNCERTAINTY ROBUST BEAMFORMING 22

PATH UNCERTAINTY ROBUST BEAMFORMING

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22nd European Signal Processing Conference (EUSIPCO)

作者： Stanton, Richard Brookes, Mike Imperial Coll London London England

ISBN: (纸本)9780992862619

Conventional beamformer design assumes that the phase differences between the received sensor signals are a deterministic function of the array and source geometry. In fact however, these phase differences are subject to random variations arising both from source and sensor position uncertainties and from fluctuations in sound velocity. We present a framework for modelling these uncertainties and show that improved beamformers are obtained when they are taken into account.

关键词： robust beamforming distributed array SNR beamformer steering vector mismatch

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PATH UNCERTAINTY ROBUST BEAMFORMING

PATH UNCERTAINTY ROBUST BEAMFORMING

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European Signal Processing Conference

作者： Richard Stanton Mike Brookes Imperial College London

ISBN: (纸本)9781479946037

关键词： Robust beamforming distributed array SNR beamformer Steering vector mismatch

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Design and Qualitative/Quantitative Analysis of Multi-Agent Spatial Simulation Library

Design and Qualitative/Quantitative Analysis of Multi-Agent ...

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作者： Chuang, Timothy University of Washington

学位级别：Master's

Integrating sensor networks in cloud computing gives new opportunities of using as many cloud-computing nodes as necessary to analyze real-time sensor data on the fly. However, most cloud services for parallelization such as OpenMP, MPI, and MapReduce are not always suitable for on-the-fly sensor-data analyses that are implemented as model-based, entity-based, and multi-agent simulations. To address this semantic gap between analyzing algorithms and their actual implementations, we have designed and implemented MASS: a library for multi-agent spatial simulation that composes of a user application of distributed array elements and multi-agents, each representing an individual simulation place or an active entity. All computation is enclosed in each of elements and agents that are automatically distributed over different computing nodes. Their communication is then scheduled as periodic data exchanges among those entities using their logical indices. This thesis presents the design, implementation and evaluation of the MASS library.

关键词： distributed array Multi-Agent Multi-Process Multi-Threaded Parallel Computing Spatial Data Analysis Computer science

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distributed Interference Cancellation for Cognitive Radios Using Periodic Signals of the Primary System

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2011年第9期10卷 2971-2981页

作者： Nishimori, Kentaro Yomo, Hiroyuki Popovski, Petar Niigata Univ Fac Engn Nishi Ku Niigata 2390847 Japan Aalborg Univ Dept Elect Syst DK-9220 Aalborg Denmark Kansai Univ Fac Engn Sci Suita Osaka 5648680 Japan

This paper considers secondary usage of spectrum resources that are allocated to frequency division duplexing (FDD)-based cellular systems. We propose an interference cancellation technique using the concept of distributed antenna array. We show that the interference from the primary cellular system can be cancelled at a secondary node equipped with single antenna by introducing a helper that decodes the interference and transfers it to the secondary node. Interference is forwarded during the time periods in which training signals are transmitted within the primary cellular system. Since the duration of those intervals is short relative to periods for data transmission in the primary system, we introduce a scheme by which the helper compresses the interference before forwarding it. The performance advantage of our scheme is verified by computer simulation, where both analytical and measured channel models are used. The measurement data used in evaluations have been obtained through outdoor experiments while assuming a short-range secondary system. The results indicate that the proposed method for distributed interference cancellation leads to performance benefit, in particular under heterogeneous path loss conditions between the helper and the primary/secondary nodes.

关键词： Secondary spectrum usage periodic training signal FDD systems distributed array interference information transfer

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Performance analysis for collaborative decoding with least-reliable-bits exchange on AWGN channels

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IEEE TRANSACTIONS ON COMMUNICATIONS 2008年第1期56卷 58-69页

作者： Li, Xin Wong, Tan F. Shea, John M. Univ Florida Dept Elect & Comp Engn Wireless Informat Networking Grp Gainesville FL 32611 USA

Collaborative decoding is an approach that can achieve diversity and combining gain by exchanging decoding information among a cluster of physically separated receivers. On AWGN channels, the least-reliable-bits (LRB) exchange scheme can achieve performance close to equal-gain combining (EGC) of all received symbols from all receivers, while reducing the amount of information that must be exchanged. In this paper, we analyze the error performance of collaborative decoding with the LRB exchange scheme when nonrecursive convolutional codes are used. The analysis is based on the observation that the extrinsic information generated in the collaborative decoding of these convolutional codes can be approximated by Gaussian random variables. A density-evolution model based on a single maximum a posteriori decoder is used to obtain the statistical characteristics of the extrinsic information. With the statistical knowledge of the extrinsic information, we develop an approximate upper bound for the error performance of the collaborative decoding process. Numerical results show that our analysis gives very good predictions of the bit error rate for collaborative decoding with LRB exchange. At high signal-to-noise ratios collaborative decoding with properly chosen parameters can achieve the same error performance as EGC of all received symbols from all receiving nodes.

关键词： collaborative decoding distributed array density evolution iterative decoding analysis

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Transmission Equation for Multiple Cooperative Transmitters and Collective Beamforming

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2008年 7卷 606-608页

作者： Jenn, David C. USN Dept Elect & Comp Engn Postgrad Sch Monterey CA 93943 USA

A general transmission equation is derived for multiple simultaneous transmitters of arbitrary phase coherence. A closed form result is obtained by examining the expected value of the power at the output of the receiv... 详细信息

关键词： Beamforming distributed array Friis equation

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distributed interference cancellation for dynamic spectrum sharing

Distributed interference cancellation for dynamic spectrum s...

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IEEE International Conference on Communications (ICC 2008)

作者： Nishimori, Kentaro Yomo, Hiroyuki Popovski, Petar Takatori, Yasushi Prasad, Ramjee Kubota, Shuji NTT Corp NTT Network Innovat Labs 1-1 Hikari No Oka Yokosuka Kanagawa 2390847 Japan Aalborg Univ Dept Elect Syst DN-9220 Aalborg Denmark

ISBN: (纸本)9781424420742

This paper proposes a novel interference cancellation technique using the concept of a distributed array, for the secondary use of the frequency resources in frequency division duplexing (FDD) based cellular systems. In order to achieve efficient distributed interference cancellation, the secondary system exploit intervals for periodic training signals transmitted by FDD-time division multiple access (TDMA) based cellular systems. We show that an efficient interference cancellation can be achieved by introducing helpers that decode the interference and transfer it to the secondary nodes. We take advantage of the high-speed links within the secondary system and devise a data compressing scheme that reduces time for transferring the decoded interference. We clarify the effectiveness of the proposed scheme by using computer simulation. As a parameter, the transmission quality between the helper and secondary nodes is varied. The results indicate that the proposed distributed interference cancellation is effective compared to a conventional adaptive array using a zero forcing algorithm, when the signal to noise ratio between the helper and the target secondary node is greater than 20 dB.

关键词： secondary spectrum usage periodic tracing signal FDD systems distributed array interference information transfer

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