In this paper we present a framework to analyze the asymptotic behavior of two timescale stochastic approximation algorithms including those with set-valued mean fields. This paper builds on the works of Borkar and Pe...
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In this paper we present a framework to analyze the asymptotic behavior of two timescale stochastic approximation algorithms including those with set-valued mean fields. This paper builds on the works of Borkar and Perkins & Leslie. The framework presented herein is more general as compared to the synchronous two timescale framework of Perkins & Leslie, however the assumptions involved are easily verifiable. As an application, we use this framework to analyze the two timescale stochasticapproximation algorithm corresponding to the Lagrangian dual problem in optimization theory.
stochastic approximation algorithms have been the subject of an enormous body of literature, both theoretical and applied. Recently, Laruelle and Pages [Ann. Appl. Probab. 23 (2013) 1409-1436] presented a link between...
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stochastic approximation algorithms have been the subject of an enormous body of literature, both theoretical and applied. Recently, Laruelle and Pages [Ann. Appl. Probab. 23 (2013) 1409-1436] presented a link between the stochasticapproximation and response-adaptive designs in clinical trials based on randomized urn models investigated in Bai and Hu [stochastic Process. Appl. 80 (1999) 87-101;Ann. Appl. Probab. 15 (2005) 914-940], and derived the asymptotic normality or central limit theorem for the normalized procedure using a central limit theorem for the stochasticapproximation algorithm. However, the classical central limit theorem for the stochasticapproximation algorithm does not include all cases of its regression function, creating a gap between the results of Laruelle and Pages [Ann. Appl. Probab. 23 (2013) 1409-1436] and those of Bai and Hu [Ann. Appl. Probab. 15 (2005) 914-940] for randomized urn models. In this paper, we establish new central limit theorems of the stochasticapproximation algorithm under the popular Lindeberg condition to fill this gap. Moreover, we prove that the process of the algorithms can be approximated by a Gaussian process that is a solution of a stochastic differential equation. In our application, we investigate a more involved family of urn models and related adaptive designs in which it is possible to remove the balls from the urn, and the expectation of the total number of balls updated at each stage is not necessary a constant. The asymptotic properties are derived under much less stringent assumptions than those in Bai and Hu [stochastic Process. Appl. 80 (1999) 87-101;Ann. Appl. Probab. 15 (2005) 914-940] and Laruelle and Pages [Ann. Appl. Probab. 23 (2013) 1409-1436].
Smoothed functional gradient algorithm with perturbations distributed according to the Gaussian distribution is considered for stochastic optimization problem with additive noise. A stochasticapproximation algorithm ...
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Given a finite connected graph G, place a bin at each vertex. Two bins are called a pair if they share an edge of G. At discrete times, a ball is added to each pair of bins. In a pair of bins, one of the bins gets the...
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Given a finite connected graph G, place a bin at each vertex. Two bins are called a pair if they share an edge of G. At discrete times, a ball is added to each pair of bins. In a pair of bins, one of the bins gets the ball with probability proportional to its current number of balls raised by some fixed power >0. We characterize the limiting behavior of the proportion of balls in the bins. The proof uses a dynamical approach to relate the proportion of balls to a vector field. Our main result is that the limit set of the proportion of balls is contained in the equilibria set of the vector field. We also prove that if <1 then there is a single point v=v(G,) with non-zero entries such that the proportion converges to v almost surely. A special case is when G is regular and 1. We show e.g. that if G is non-bipartite then the proportion of balls in the bins converges to the uniform measure almost *** (c) 2013 Wiley Periodicals, Inc. Random Struct. Alg., 46,614-634, 2015
This paper considers a Markov-modulated duplication-deletion random graph where at each time instant, one node can either join or leave the network;the probabilities of joining or leaving evolve according to the reali...
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This paper considers a Markov-modulated duplication-deletion random graph where at each time instant, one node can either join or leave the network;the probabilities of joining or leaving evolve according to the realization of a finite state Markov chain. Two results are presented. First, motivated by social network applications, the asymptotic behavior of the degree distribution is analyzed. Second, a stochasticapproximation algorithm is presented to track empirical degree distribution as it evolves over time. The tracking performance of the algorithm is analyzed in terms of mean square error and a functional central limit theorem is presented for the asymptotic tracking error. Also, a Hilbert-space-valued stochasticapproximation algorithm that tracks a Markov-modulated probability mass function with support on the set of nonnegative integers is analyzed.
作者:
Chen, JunCALTECH
Div Humanities & Social Sci Pasadena CA 91125 USA
We consider two particles' repelling random walks on complete graphs. In this model, each particle has higher probability to visit the vertices which have been seldom visited by the other one. By a dynamical appro...
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We consider two particles' repelling random walks on complete graphs. In this model, each particle has higher probability to visit the vertices which have been seldom visited by the other one. By a dynamical approach we prove that the two particles' occupation measure asymptotically has small joint support almost surely if the repulsion is strong enough.
We obtain new transport-entropy inequalities and, as a by-product, new deviation estimates for the laws of two kinds of discrete stochasticapproximation schemes. The first one refers to the law of an Euler like discr...
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We obtain new transport-entropy inequalities and, as a by-product, new deviation estimates for the laws of two kinds of discrete stochasticapproximation schemes. The first one refers to the law of an Euler like discretization scheme of a diffusion process at a fixed deterministic date and the second one concerns the law of a stochasticapproximation algorithm at a given time-step. Our results notably improve and complete those obtained in [10]. The key point is to properly quantify the contribution of the diffusion term to the concentration regime. We also derive a general non-asymptotic deviation bound for the difference between a function of the trajectory of a continuous Euler scheme associated to a diffusion process and its mean. Finally, we obtain non-asymptotic bound for stochasticapproximation with averaging of trajectories, in particular we prove that averaging a stochasticapproximation algorithm with a slow decreasing step sequence gives rise to optimal concentration rate.
Pricing is an effective tool to control congestion and achieve quality of service (QoS) provisioning for multiple differentiated levels of service. In this paper, we consider the problem of pricing for congestion cont...
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Pricing is an effective tool to control congestion and achieve quality of service (QoS) provisioning for multiple differentiated levels of service. In this paper, we consider the problem of pricing for congestion control in the case of a network of nodes with multiple queues and multiple grades of service. We present a closed-loop multi-layered pricing scheme and propose an algorithm for finding the optimal state dependent price levels for individual queues, at each node. This is different from most adaptive pricing schemes in the literature that do not obtain a closed-loop state dependent pricing policy. The method that we propose finds optimal price levels that are functions of the queue lengths at individual queues. Further, we also propose a variant of the above scheme that assigns prices to incoming packets at each node according to a weighted average queue length at that node. This is done to reduce frequent price variations and is in the spirit of the random early detection (RED) mechanism used in TCP/IP networks. We observe in our numerical results a considerable improvement in performance using both of our schemes over that of a recently proposed related scheme in terms of both throughput and delay performance. In particular, our first scheme exhibits a throughput improvement in the range of 67-82% among all routes over the above scheme. (C) 2011 Elsevier B.V. All rights reserved.
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