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50
Mobility increases the capacity of adhoc wireless networks
 IEEE/ACM TRANSACTIONS ON NETWORKING
, 2002
"... The capacity of adhoc wireless networks is constrained by the mutual interference of concurrent transmissions between nodes. We study a model of an adhoc network where n nodes communicate in random sourcedestination pairs. These nodes are assumed to be mobile. We examine the persession throughpu ..."
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Cited by 1218 (6 self)
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The capacity of adhoc wireless networks is constrained by the mutual interference of concurrent transmissions between nodes. We study a model of an adhoc network where n nodes communicate in random sourcedestination pairs. These nodes are assumed to be mobile. We examine the persession throughput for applications with loose delay constraints, such that the topology changes over the timescale of packet delivery. Under this assumption, the peruser throughput can increase dramatically when nodes are mobile rather than fixed. This improvement can be achieved by exploiting node mobility as a type of multiuser diversity.
Genetic Algorithms, Tournament Selection, and the Effects of Noise
 Complex Systems
, 1995
"... Tournament selection is a useful and robust selection mechanism commonly used by genetic algorithms. The selection pressure of tournament selection directly varies with the tournament size  the more competitors, the higher the resulting selection pressure. This article develops a model, based on ..."
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Cited by 132 (14 self)
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Tournament selection is a useful and robust selection mechanism commonly used by genetic algorithms. The selection pressure of tournament selection directly varies with the tournament size  the more competitors, the higher the resulting selection pressure. This article develops a model, based on order statistics, that can be used to quantitatively predict the resulting selection pressure of a tournament of a given size. This model is used to predict the convergence rates of genetic algorithms utilizing tournament selection. While tournament selection is often used in conjunction with noisy (imperfect) fitness functions, little is understood about how the noise affects the resulting selection pressure. The model is extended to quantitatively predict the selection pressure for tournament selection utilizing noisy fitness functions. Given the tournament size and noise level of a noisy fitness function, the extended model is used to predict the resulting selection pressure of tournament...
LoadSharing in Heterogeneous Systems via Weighted Factoring
 in Proceedings of the 8th Annual ACM Symposium on Parallel Algorithms and Architectures
, 1997
"... We consider the problem of scheduling a parallel loop with independent iterations on a network of heterogeneous workstations, and demonstrate the effectiveness of a variant of factoring, a scheduling policy originating in the context of shared addressspace homogeneous multiprocessors. In the new s ..."
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Cited by 42 (0 self)
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We consider the problem of scheduling a parallel loop with independent iterations on a network of heterogeneous workstations, and demonstrate the effectiveness of a variant of factoring, a scheduling policy originating in the context of shared addressspace homogeneous multiprocessors. In the new scheme, weighted factoring, processors are dynamically assigned decreasing size chunks of iterations in proportion to their processing speeds. Through experiments on a network of SUN Sparc workstations we show that weighted factoring significantly outperforms variants of a workstealing loadbalancing algorithm and on certain applications dramatically outperforms factoring as well. We then study weighted work assignment analytically, giving upper and lower bounds on its performance under the assumption that the processor iteration execution times can be modeled as weighted random variables. Department of Computer Science, Polytechnic University, Brooklyn, NY, 11201. Research supported by AR...
Parameter Estimation for the Truncated Pareto Distribution
 Journal of the American Statistical Assoc
, 2006
"... The Pareto distribution is a simple model for nonnegative data with a power law probability tail. In many practical applications, there is a natural upper bound that truncates the probability tail. This paper derives estimators for the truncated Pareto distribution, investigates their properties, a ..."
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Cited by 23 (4 self)
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The Pareto distribution is a simple model for nonnegative data with a power law probability tail. In many practical applications, there is a natural upper bound that truncates the probability tail. This paper derives estimators for the truncated Pareto distribution, investigates their properties, and illustrates a way to check for fit. We illustrate these methods with applications from finance, hydrology and atmospheric science.
On the optimality of spectral compression of mesh data
 ACM Trans. Graph
, 2005
"... Spectral compression of the geometry of triangle meshes achieves good results in practice, but there has been little or no theoretical support for the optimality of this compression. We show that, for certain classes of geometric mesh models, spectral decomposition using the eigenvectors of the symm ..."
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Cited by 17 (0 self)
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Spectral compression of the geometry of triangle meshes achieves good results in practice, but there has been little or no theoretical support for the optimality of this compression. We show that, for certain classes of geometric mesh models, spectral decomposition using the eigenvectors of the symmetric Laplacian of the connectivity graph is equivalent to principal component analysis on that class, when equipped with a natural probability distribution. Our proof treats connected oneand twodimensional meshes with fixed convex boundaries, and is based on an asymptotic approximation of the probability distribution in the twodimensional case. The key component of the proof is that the Laplacian is identical, up to a constant factor, to the inverse covariance matrix of the distribution of valid mesh geometries. Hence, spectral compression is optimal, in the mean square error sense, for these classes of meshes under some natural assumptions on their distribution.
Downlink Scheduling Schemes in Cellular Packet Data Systems of MultipleInput MultipleOutput Antennas
 in Proc. IEEE GLOBECOM
, 2004
"... Highspeed cellular data systems demand fast downlink scheduling algorithms and MultipleInput MultipleOutput (MIMO) techniques. The associated multiuser diversity and antenna diversity play a central role in achieving high system throughput and fair resource allocation among multiple users. For su ..."
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Cited by 14 (2 self)
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Highspeed cellular data systems demand fast downlink scheduling algorithms and MultipleInput MultipleOutput (MIMO) techniques. The associated multiuser diversity and antenna diversity play a central role in achieving high system throughput and fair resource allocation among multiple users. For such systems we evaluate the crosslayer interactions between channeldependent scheduling schemes and MIMO techniques, such as SpaceTime Block Coding (STBC) or Bell Labs Layered SpaceTime (BLAST), and propose a new scheduling algorithm named the AlphaRule. The evaluation shows that the STBC/MIMO provides reliable channel but at certain cost of spectral efficiency. Comparatively BLAST/MIMO provides larger capacity and enables higher scheduling throughput. Thus BLAST/MIMO may be a more suitable technique for highrate packet data transmission at the physical layer. At the medium access control (MAC)layer, the AlphaRule is shown to be more flexible or efficient to exploit the diversity gains than the exiting maxC/I or Proportionally Fair (PF) scheduling schemes. It enables online tradeoff between aggregate throughput, peruser throughput, and peruser resource allocation.
Gene selection criterion for discriminant microarray data analysis based on extreme value distributions
 In RECOMB ’03: Proceedings of the Seventh Annual International Conference on Research in Computational Molecular Biology
, 2003
"... An important issue commonly encountered in the analysis of microarray data is to decide which and how many genes should be selected for further studies. For discriminant microarray data analyses based on statistical models, such as the logistic regression model, this gene selection can be accomplish ..."
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Cited by 9 (0 self)
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An important issue commonly encountered in the analysis of microarray data is to decide which and how many genes should be selected for further studies. For discriminant microarray data analyses based on statistical models, such as the logistic regression model, this gene selection can be accomplished by a comparison of the maximum likelihood of the model given the real data, ˆL(DM), and the expected maximum likelihood of the model given an ensemble of surrogate data, ˆ L(D0M). Typically, the computational burden for obtaining ˆ L(D0M) is immense, often exceeding the limits of available resources by orders of magnitude. Here, we propose an approach that circumvents such heavy computations by mapping the simulation problem to an extreme value problem, which can be easily solved by numerical simulation. We choose three classification problems from two publicly available microarray datasets to illustrate that approach.
Large system performance of interference alignment in singlebeam MIMO networks
 in Proc. IEEE Global Telecommun. Conf., (GLOBECOM
, 2010
"... Abstract—We consider a network of K interfering transmitterreceiver pairs, where each node has N antennas and at most one beam is transmitted per user. We investigate the asymptotic performance of different beamforming strategies, as characterized by the slope and yaxis intercept (or offset) of t ..."
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Cited by 6 (0 self)
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Abstract—We consider a network of K interfering transmitterreceiver pairs, where each node has N antennas and at most one beam is transmitted per user. We investigate the asymptotic performance of different beamforming strategies, as characterized by the slope and yaxis intercept (or offset) of the high signaltonoiseratio (SNR) sum rate asymptote. It is known that a slope (or multiplexing gain) of 2N − 1 is achievable with interference alignment. On the other hand, a strategy achieving a slope of only N might allow for a significantly higher offset. Assuming that the number of fully aligned beamformer sets that achieve a slope of 2N − 1 is finite for a given channel realization, we approximate the average offset when the best out of a large number L of these sets is selected. We also derive a simple large system approximation for the sum rate of a successive beam allocation scheme when K = N. We show that both approximations accurately predict simulated results for moderate system dimensions and characterize the largesystem asymptotes for different relationships between L and N. I.
Bounds on the distribution of a sum of correlated lognormal random variables and their application
 IEEE Trans. Commun
, 2008
"... Abstract—The cumulative distribution function (cdf) of a sum of correlated or even independent lognormal random variables (RVs), which is of wide interest in wireless communications, remains unsolved despite long standing efforts. Several cdf approximations are thus widely used. This letter derives ..."
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Cited by 5 (1 self)
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Abstract—The cumulative distribution function (cdf) of a sum of correlated or even independent lognormal random variables (RVs), which is of wide interest in wireless communications, remains unsolved despite long standing efforts. Several cdf approximations are thus widely used. This letter derives bounds for the cdf of a sum of 2 or 3 arbitrarily correlated lognormal RVs and of a sum of any number of equallycorrelated lognormal RVs. The bounds are singlefold integrals of readily computable functions and extend previously known bounds for independent lognormal summands. An improved set of bounds are also derived which are expressed as 2fold integrals. For correlated lognormal fading channels, new expressions are derived for the moments of the output SNR and amount of fading for maximal ratio combining (MRC), selection combining (SC) and equal gain combining (EGC) and outage probability expressions for SC. Index Terms—Amount of fading, cochannel interference, lognormal distribution, diversity combining.