This paper concerns active noise control (ANC) of impulsive noise modeled using non-Gaussian stable processes. The most famous filtered-x least mean square (FxLMS) algorithm for ANC systems is based on minimization of...
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This paper concerns active noise control (ANC) of impulsive noise modeled using non-Gaussian stable processes. The most famous filtered-x least mean square (FxLMS) algorithm for ANC systems is based on minimization of variance of error signal. For the impulse noise, the FxLMS algorithm becomes unstable, as second-order moments do not exist for non-Gaussian processes. Among the existing algorithms for ANC of impulsive noise, one is based on minimizing least mean p-power (LMP) of the error signal, resulting in FxLMP algorithm. The other is based on modifying, on the basis of statistical properties, the reference signal in update of FxLMS algorithm. In this paper, the proposed algorithm is an extension of the later approach. Extensive simulations are carried out, which demonstrate the effectiveness of the proposed algorithm. It achieves the best performance among the existing algorithms, and at the same computational complexity as that of FxLMS algorithm. (C) 2009 Elsevier Ltd. All rights reserved.
BECAUSE CONVENTIONAL SOFTWARE-BASED PACKET INSPECTION algorithms HAVE NOT KEPT PACE WITH HIGH-SPEED NETWORKS, INTEREST HAS TURNED TO USING HARDWARE TO PROCESS NETWORK DATA QUICKLY. STRING SCANNING WITH BLOOM FILTERS C...
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BECAUSE CONVENTIONAL SOFTWARE-BASED PACKET INSPECTION algorithms HAVE NOT KEPT PACE WITH HIGH-SPEED NETWORKS, INTEREST HAS TURNED TO USING HARDWARE TO PROCESS NETWORK DATA QUICKLY. STRING SCANNING WITH BLOOM FILTERS CAN SCAN ENTIRE PACKET PAYLOADS FOR PREDEFINED SIGNATURES AT MULTI-GIGABIT-PER-SECOND LINE SPEEDS.
In semi-online scheduling problems, we always assume that some partial additional information is exactly known in advance. This may not be true in some application. This paper considers semi-online problems on identic...
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In semi-online scheduling problems, we always assume that some partial additional information is exactly known in advance. This may not be true in some application. This paper considers semi-online problems on identical machines with inexact partial information. Three problems are considered, where we know in advance that the optimal value, or the largest job size are in given intervals, respectively, while their exact values are unknown. We give both lower bounds of the problems and competitive ratios of algorithms as functions of a so-called disturbance parameter r is an element of [1, infinity). We establish for which r the inexact partial information is useful to improve the performance of a semi-online algorithm with respect to its pure online problem. Optimal preemptive semi-online algorithms are then obtained.
Texture and color information as important characters of video objects have been widely used in the detection of moving objects. A detection algorithm based on texture may cause detection errors in regions of blank te...
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Texture and color information as important characters of video objects have been widely used in the detection of moving objects. A detection algorithm based on texture may cause detection errors in regions of blank texture and heterogeneous texture, and a detection algorithm based on color is easily influenced by illumination changes and shadows. In this paper, a new detection and fusion algorithm is proposed. At the detection stage based on texture, the background texture is classified according to the steering kernel. At the fusion stage, for the moving objects detected on the basis of texture and color respectively, a scheme based on a boundary selection strategy is proposed for combining the different detection objects. A relatively smooth boundary is selected as the true boundary, and the shadow detection is carried out to assist the boundary selection. Experimental results verify the advantages of the proposed algorithm as compared to the existing state-of-the-art algorithms. (C) 2012 Elsevier Ltd. All rights reserved.
Service-oriented computing is revolutionizing the modern computing paradigms with its aim to boost software reuse and enable business agility. Under this paradigm, new services are fabricated by composing available se...
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Service-oriented computing is revolutionizing the modern computing paradigms with its aim to boost software reuse and enable business agility. Under this paradigm, new services are fabricated by composing available services. The problem arises as how to effectively and efficiently compose heterogeneous services facing the high complexity of service composition. Based on environment ontology, this paper introduces a requirement-driven service composition approach. We propose the algorithms to decompose the requirement, the rules to deduct the relation between services, and the algorithm for composing service. The empirical results and the comparison with other services' composition methodologies show that this approach is feasible and efficient.
This paper proposes a new real-time communication scheme for 802.11e wireless networks. This scheme is called Group Sequential Communication (GSC). The GSC improves the efficiency of the Hybrid Coordination Function C...
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This paper proposes a new real-time communication scheme for 802.11e wireless networks. This scheme is called Group Sequential Communication (GSC). The GSC improves the efficiency of the Hybrid Coordination Function Controlled Channel Access (HCCA) mechanism by reducing the protocol overheads of the 802.11e amendment. The GSC approach eliminates the polling scheme used in traditional scheduling algorithm, by means of a virtual token passing procedure among members of the real-time group to whom is granted a high-priority and sequential access to communication medium. In order to improve the reliability of the proposed scheme, it is also proposed an error recovery mechanism based on block acknowledgment. The GSC was implemented in network simulator software and the performance results were compared to HCCA scheme, showing the efficient of the proposed approach when dealing with traditional industrial communication scenarios. (C) 2012 Elsevier Ltd. All rights reserved.
Shared counters are among the most basic coordination structures in distributed computing. Known implementations of shared counters are either blocking, non-linearizable, or have a sequential bottleneck. We present th...
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Shared counters are among the most basic coordination structures in distributed computing. Known implementations of shared counters are either blocking, non-linearizable, or have a sequential bottleneck. We present the first counter algorithm that is both linearizable, non-blocking, and can provably achieve high throughput in k-synchronous executions-executions in which process speeds vary by at most a constant factor k. The algorithm is based on a novel variation of the software combining paradigm that we call bounded-wait combining (BWC). It can thus be used to obtain implementations, possessing the same properties, of any object that supports combinable operations, such as a stack or a queue. Unlike previous combining algorithms where processes may have to wait for each other indefinitely, in the BWC algorithm, a process only waits for other processes for a bounded period of time and then "takes destiny in its own hands". In order to reason rigorously about the parallelism attainable by our algorithm, we define a novel metric for measuring the throughput of shared objects, which we believe is interesting in its own right. We use this metric to prove that our algorithm achieves throughput of Omega(N/ log N) in k-synchronous executions, where N is the number of processes that can participate in the algorithm. Our algorithm uses two tools that we believe may prove useful for obtaining highly parallel non-blocking implementation of additional objects. The first are "synchronous locks", locks that are respected by processes only in k-synchronous executions and are disregarded otherwise;the second are "pseduo-transactions"aEuro"a weakening of regular transactions that allows higher parallelism.
Existing methods on structural controllability of networked systems are based on critical assumptions such as nodal dynamics with infinite time constants and availability of input signals to all nodes. In this paper, ...
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Existing methods on structural controllability of networked systems are based on critical assumptions such as nodal dynamics with infinite time constants and availability of input signals to all nodes. In this paper, we relax these assumptions and examine the structural controllability for practical model of networked systems. We explore the relationship between structural controllability and graph reachability. Consequently, a simple graph-based algorithm is presented to obtain the minimum driver nodes. Finally, simulation results are presented to illustrate the performance of the proposed algorithm in dealing with large-scale networked systems.
The unified power flow controller (UPFC) is a tool in the implementation of Flexible AC Transmission Systems (FACTS), It provides for the equivalent of static VAr compensation and series injection using back-to-back f...
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The unified power flow controller (UPFC) is a tool in the implementation of Flexible AC Transmission Systems (FACTS), It provides for the equivalent of static VAr compensation and series injection using back-to-back force commutated converters, This paper proposes a control strategy to extend UPFC operation to allow for the isolation of harmonics due to nonlinear loads. Simulation results based on the Electromagnetic Transients Program (EMTP) are used to illustrate device performance in a power system environment. Experimental results based on a single phase laboratory implementation verify the proposed control algorithm.
In this work, modulo 2(n) + 1 fused architectures of dot product and generalized multiply-add units for operands in the weighted representation are proposed. According to our algorithm, the partial products and the ad...
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In this work, modulo 2(n) + 1 fused architectures of dot product and generalized multiply-add units for operands in the weighted representation are proposed. According to our algorithm, the partial products and the additive operands are efficiently added using inverted end around carry-save adder trees. This approach results to large savings on delay, area and power compared to using discrete units. Optimization techniques and implementation results for units with practical interest are also given. The proposed modulo 2(n) + 1 arithmetic units can be utilized in all applications where the residue number system is used for the implementation of digital signal processing and cryptography algorithms. (C) 2012 Elsevier Ltd. All rights reserved.
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