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Good Tradeoff (good + tradeoff)
Selected AbstractsThe Neutralizer: a self-configurable failure detector for minimizing distributed storage maintenance costCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 2 2009Zhi Yang Abstract To achieve high data availability or reliability in an efficient manner, distributed storage systems must detect whether an observed node failure is permanent or transient, and if necessary, generate replicas to restore the desired level of replication. Given the unpredictability of network dynamics, however, distinguishing permanent and transient failures is extremely difficult. Though timeout-based detectors can be used to avoid mistaking transient failures as permanent failures, it is unknown how the timeout values should be selected to achieve a better tradeoff between detection latency and accuracy. In this paper, we address this fundamental tradeoff from several perspectives. First, we explore the impact of different timeout values on maintenance cost by examining the probability of their false positives and false negatives. Second, we propose a self-configurable failure detector called the Neutralizer based on the idea of counteracting false positives with false negatives. The Neutralizer could enable the system to maintain a desired replication level on average with the least amount of bandwidth. We conduct extensive simulations using real trace data from a widely deployed peer-to-peer system and synthetic traces based on PlanetLab and Microsoft PCs, showing a significant reduction in aggregate bandwidth usage after applying the Neutralizer (especially in an environment with a low average node availability). Overall, we demonstrate that the Neutralizer closely approximates the performance of a perfect ,oracle' detector in many cases. Copyright © 2008 John Wiley & Sons, Ltd. [source] Iterative channel estimation and data detection in frequency-selective fading MIMO channels,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2004Maja Lon Signals transmitted through multiple-input multiple-output (MIMO) wireless channels suffer from multiple-access interference (MAI), multipath propagation and additive noise. Iterative multiuser receiver algorithms mitigate these signal impairments, while offering a good tradeoff between performance and complexity. The receiver presented in this paper performs channel estimation, multiuser detection and decoding in an iterative manner. The estimation of the frequency selective, block-fading channel is initiated with the pilot symbols. In subsequent iterations, soft decisions of all the data symbols are used in an appropriate way to improve the channel estimates. This approach leads to significant improvement of the overall receiver performance, compared to other schemes. The bit-error-rate (BER) performance of the receiver is evaluated by simulations for different parameter setups. Copyright © 2004 AEI. [source] The Gauss-Seidel fast affine projection algorithm for multichannel active noise control and sound reproduction systemsINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 2-3 2005Martin Bouchard Abstract In the field of adaptive filtering, the fast implementations of affine projection algorithms are known to provide a good tradeoff between convergence speed and computational complexity. Such algorithms have recently been published for multichannel active noise control systems. Previous work reported that these algorithms can outperform more complex recursive least-squares algorithms when noisy plant models are used in active noise control systems. This paper proposes a new fast affine projection algorithm for multichannel active noise control or sound reproduction systems, based on the Gauss,Seidel solving scheme. The proposed algorithm has a lower complexity than the previously published algorithms, with the same convergence speed and the same good performance with noisy plant models, and a potential for better numerical stability. It provides the best performance/cost ratio. Details of the algorithm and its complexity are presented in the paper, with simulation results to validate its performance. Copyright © 2004 John Wiley & Sons, Ltd. [source] Ruthenium (II) tris-bathophenanthroline disulfonate is well suitable for Tris-Glycine PAGE but not for Bis-Tris gelsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 4 2007Jan Moebius Abstract Pre-cast bis(2-hydroxyethyl)iminotris(hydroxymethyl)methane (Bis-Tris) gels have proven to be very suitable for pre-fractionation for LC-MS/MS analysis due to high reliability and long stability. To visualize proteins within gels fluorescence dyes proved to be a good tradeoff between sensitivity and MS-compatibility. The custom-made ruthenium dye represents a low-cost alternative regarding fluorescence-based protein visualization with high sensitivity. We demonstrate, that this dye is incompatible with Bis-Tris gels, while using Tris-Glycine gels a competitive sensitivity to commercially available stains can be achieved. [source] | ||||||||||