The Experts below are selected from a list of 24894 Experts worldwide ranked by ideXlab platform
Weihua Zhuang - One of the best experts on this subject based on the ideXlab platform.
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channel precoding with small envelope variations for spl pi 4 qpsk and msk over frequency selective slow fading channels
IEEE Transactions on Vehicular Technology, 2003Co-Authors: Weihua ZhuangAbstract:This paper presents channel precoding schemes to combat intersymbol interference (ISI) over a frequency-selective slow fading channel in wireless communication systems using /spl pi//4 shifted quadrature phase-shift keying or minimum shift keying. Based on the dimension Partitioning Technique, the precoders predistort the phase of the transmitted symbol in the forward link to combat ISI, keeping the transmitted symbol amplitude constant. The proposed schemes can ensure the stability of the precoder even in equalizing a nonminimum-phase channel, combat ISI without increasing the complexity of portable unit receivers, and reduce the envelope variations of transmitted signals such that power-efficient nonlinear amplifiers can be used for the precoded signals without causing a significant undue distortion. Theoretical analysis and simulation results are presented to demonstrate the effectiveness of the proposed channel precoding schemes.
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channel precoding for spl pi 4 dqpsk and msk over frequency selective slow fading channels
Vehicular Technology Conference, 2000Co-Authors: Weihua ZhuangAbstract:This paper presents channel precoding schemes to combat intersymbol interference (ISI) over a frequency-selective slow fading channel in wireless communication systems using /spl pi//4 differential quadrature phase shift keying (/spl pi//4-DQPSK) or minimum shift keying (MSK). Based on the dimension Partitioning Technique, the precoders predistort the phase of the transmitted signals in the forward link to combat ISI, keeping the transmitted signal amplitude constant. The precoding schemes can (i) ensure the stability of the precoders even in equalizing a non-minimum-phase channel, (ii) achieve ISI-free transmission without increasing the complexity of the portable unit receiver and (iii) reduce the envelope variations of transmitted signals such that a power efficient nonlinear amplifier can be used without causing undue distortion. Theoretical and simulation results are presented to demonstrate that the proposed channel precoders can outperform DFE when the ISI is severe and the precoding scheme for /spl pi//4-DQPSK can achieve a smaller envelope variation than the standard /spl pi//4-DQPSK.
Minesh B. Amin - One of the best experts on this subject based on the ideXlab platform.
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a scalable parallel formulation of the backpropagation algorithm for hypercubes and related architectures
IEEE Transactions on Parallel and Distributed Systems, 1994Co-Authors: Vipin Kumar, Shashi Shekhar, Minesh B. AminAbstract:We present a new Technique for mapping the backpropagation algorithm on hypercube and related architectures. A key component of this Technique is a network Partitioning scheme called checkerboarding. Checkerboarding allows us to replace the all-to-all broadcast operation performed by the commonly used vertical network Partitioning scheme, with operations that are much faster on the hypercubes and related architectures. Checkerboarding can be combined with the pattern Partitioning Technique to form a hybrid scheme that performs better than either one of these schemes. Theoretical analysis and experimental results on nCUBE and CM5 show that our scheme performs better than the other schemes, for both uniform and nonuniform networks. >
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a scalable parallel formulation of the backpropagation algorithm for hypercubes and related architectures
IEEE Transactions on Parallel and Distributed Systems, 1994Co-Authors: Vipin Kumar, Shashi Shekhar, Minesh B. AminAbstract:We present a new Technique for mapping the backpropagation algorithm on hypercube and related architectures. A key component of this Technique is a network Partitioning scheme called checkerboarding. Checkerboarding allows us to replace the all-to-all broadcast operation performed by the commonly used vertical network Partitioning scheme, with operations that are much faster on the hypercubes and related architectures. Checkerboarding can be combined with the pattern Partitioning Technique to form a hybrid scheme that performs better than either one of these schemes. Theoretical analysis and experimental results on nCUBE and CM5 show that our scheme performs better than the other schemes, for both uniform and nonuniform networks. >
Jean-paul Tillement - One of the best experts on this subject based on the ideXlab platform.
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Comparative binding of etretinate and acitretin to plasma proteins and erythrocytes.
Biochemical pharmacology, 1992Co-Authors: Saïk Urien, Pascal Claudepierre, Joseph Meyer, Roger Brandt, Jean-paul TillementAbstract:Abstract The interactions of etretinate and its main metabolite acitretin with human plasma proteins have been investigated in vitro by an erythrocyte Partitioning Technique that allows a quantitative estimation of the plasma and erythrocyte binding. Etretinate was extensively lipoprotein-bound (75% of plasma etretinate), with a binding constant for its main low density lipoprotein carrier of 40 × 10 6 M −1 , accounting for 48% of the total plasma-bound drug. Acitretin was mainly albumin-bound (91% of plasma acitretin), with a binding constant of 0.7 × 10 6 M −1 . The total plasma binding of both drugs was > 99% and, in blood, the fractions associated with erythrocytes were 14.5 and 8.1% of the total amount for etretinate and acitretin, respectively.
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Binding of a new vinca alkaloid derivative, S12363, to human plasma proteins and platelets. Usefulness of an erythrocyte Partitioning Technique
Investigational New Drugs, 1992Co-Authors: Saïk Urien, Gérard Bastian, J P Bizzari, Catherine Lucas, Jean-paul TillementAbstract:The interactions of S12363 with human plasma proteins have been investigated in vitro by an erythrocyte Partitioning Technique that allows a quantitative estimation of the plasma and erythrocytes binding. S12363 was 85–95% plasma-bound and 97–98% blood-bound. The main binding protein in plasma was alpha-acid glycoprotein, with a binding constant of 0.6·10^6 M^−1, accounting for 70% of total S12363 in plasma. Owing to extensive binding to platelets (40–50% of total blood amount), S12363 was mainly distributed in the non plasma blood compartment, with blood-to-plasma concentrations ratio of 1.2–1.4. These results indicate that, in vivo , the fraction of blood S12363 available for tissue diffusion, i.e., the free drug fraction in blood, should depend on both alpha_1-acid glycoprotein concentration in plasma and blood platelet count.
Anthony Ephremides - One of the best experts on this subject based on the ideXlab platform.
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Using Bandwidth-Space Partitioning to Improve Cell Coverage and Near-Far Unfair Access Problem in a Noise-Limited CDMA Cellular Network
Wireless Networks, 2005Co-Authors: Shih-tsung Yang, Anthony EphremidesAbstract:This paper concerns CDMA cellular networks equipped with conventional matched filter receivers. For this type of cellular networks, two problems exist. One is the inverse relationship between the coverage and capacity, and the other one is the near-far unfair access problem. To resolve these two problems, a bandwidth-space Partitioning Technique is adopted. Several admission control schemes based on the bandwidth-space Partitioning Technique are proposed, and their performances are evaluated based on the simulation.
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resolving the cdma cell breathing effect and near far unfair access problem by bandwidth space Partitioning
Vehicular Technology Conference, 2001Co-Authors: Shih-tsung Yang, Anthony EphremidesAbstract:This paper concerns CDMA cellular networks equipped with conventional matched filter receivers. For this type of cellular networks, both the cell breathing effect and near-far unfair access problem exist. The cell breathing effect is an effect that the cell coverage will shrink when supporting more users. The near-far unfair access problem means that the near users will have a lower blocking probability than far users. To solve these two problems, a bandwidth-space Partitioning Technique is adopted. Several admission control/subband assignment schemes, based on the bandwidth-space Partitioning Technique, are proposed for solving the above two problems.
Vipin Kumar - One of the best experts on this subject based on the ideXlab platform.
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divide and conquer approach for efficient pagerank computation
International Conference on Web Engineering, 2006Co-Authors: Prasanna Desikan, Nishith Pathak, Jaideep Srivastava, Vipin KumarAbstract:PageRank is a popular ranking metric for large graphs such as theWorld Wide Web. Current research Techniques for improving computational efficiency of PageRank have focussed on improving the I/O cost, convergence and parallelizing the computation process. In this paper, we propose a divide and conquer strategy for efficient computation of PageRank. The strategy is different from contemporary improvements in that itcan be combined with any existing enhancements to PageRank, giving way to an entire class of more efficient algorithms. Wepresent a novel graph-Partitioning Technique for dividing thegraph into subgraphs, on which computation can be performed independently. This approach has two significant benefits. Firstly, since the approach focuses on work-reduction, it can be combined with any existing enhancements to PageRank. Secondly, the proposed approach leads naturally into developing an incremental approach for computation of such ranking metrics given that these large graphs evolve over a period of time. The Partitioning Technique is both lossless and independent of the type (variant) ofPageRank computation algorithm used. The experimental results for a static single graph (graph at a single time instance) as well as for the incremental computation in case of evolving graphs, illustrate the utility of our novel Partitioning approach. The proposed approach can also be applied for the computation of anyother metric based on first order Markov chain model.
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a scalable parallel formulation of the backpropagation algorithm for hypercubes and related architectures
IEEE Transactions on Parallel and Distributed Systems, 1994Co-Authors: Vipin Kumar, Shashi Shekhar, Minesh B. AminAbstract:We present a new Technique for mapping the backpropagation algorithm on hypercube and related architectures. A key component of this Technique is a network Partitioning scheme called checkerboarding. Checkerboarding allows us to replace the all-to-all broadcast operation performed by the commonly used vertical network Partitioning scheme, with operations that are much faster on the hypercubes and related architectures. Checkerboarding can be combined with the pattern Partitioning Technique to form a hybrid scheme that performs better than either one of these schemes. Theoretical analysis and experimental results on nCUBE and CM5 show that our scheme performs better than the other schemes, for both uniform and nonuniform networks. >
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a scalable parallel formulation of the backpropagation algorithm for hypercubes and related architectures
IEEE Transactions on Parallel and Distributed Systems, 1994Co-Authors: Vipin Kumar, Shashi Shekhar, Minesh B. AminAbstract:We present a new Technique for mapping the backpropagation algorithm on hypercube and related architectures. A key component of this Technique is a network Partitioning scheme called checkerboarding. Checkerboarding allows us to replace the all-to-all broadcast operation performed by the commonly used vertical network Partitioning scheme, with operations that are much faster on the hypercubes and related architectures. Checkerboarding can be combined with the pattern Partitioning Technique to form a hybrid scheme that performs better than either one of these schemes. Theoretical analysis and experimental results on nCUBE and CM5 show that our scheme performs better than the other schemes, for both uniform and nonuniform networks. >
