Papers by Arpan Mukhopadhyay
Ieee Transactions on Systems Man and Cybernetics Part B Cybernetics a Publication of the Ieee Systems Man and Cybernetics Society, Feb 1, 2011
The theoretical analysis of evolutionary algorithms is believed to be very important for understa... more The theoretical analysis of evolutionary algorithms is believed to be very important for understanding their internal search mechanism and thus to develop more efficient algorithms. This paper presents a simple mathematical analysis of the explorative search behavior of a recently developed metaheuristic algorithm called harmony search (HS). HS is a derivative-free real parameter optimization algorithm, and it draws inspiration from the musical improvisation process of searching for a perfect state of harmony. This paper analyzes the evolution of the populationvariance over successive generations in HS and thereby draws some important conclusions regarding the explorative power of
2015 27th International Teletraffic Congress, 2015
We consider the job assignment problem in a multi-server system consisting of N parallel processo... more We consider the job assignment problem in a multi-server system consisting of N parallel processor sharing servers, categorized into M (≪ N ) different types according to their processing capacity or speed. Jobs of random sizes arrive at the system according to a Poisson process with rate N λ. Upon each arrival, a small number of servers from each type is sampled uniformly at random. The job is then assigned to one of the sampled servers based on a selection rule. We propose two schemes, each corresponding to a specific selection rule that aims at reducing the mean sojourn time of jobs in the system.
This paper presents a simple mathematical analysis of some features of the Harmony Search algorit... more This paper presents a simple mathematical analysis of some features of the Harmony Search algorithm (HS). HS is a recently developed derivative-free optimization algorithm, which draws inspiration from the musical process of searching for a perfect state of harmony. This work analyses the evolution of the population-variance over successive generations in HS and thereby draws some important conclusions regarding the explorative power of HS. Experimental results have been provided to validate the theoretical treatment. A simple modification of the classical HS has been proposed in the light of the mathematical analysis undertaken here.
Performance Evaluation, 2015
2014 26th International Teletraffic Congress (ITC), 2014
We analyze randomized dynamic load balancing schemes for multi-server processor sharing systems w... more We analyze randomized dynamic load balancing schemes for multi-server processor sharing systems when the number of servers in the system is large and the servers have heterogeneous service rates. In particular, we focus on the classical power-of-two load balancing scheme and a variant of it in which a newly arrived job is assigned to the server having the least instantaneous Lagrange shadow cost among two randomly chosen servers. The instantaneous Lagrange shadow cost at a server is given by the ratio of the number of unfinished jobs at the server to the capacity of the server. Two different approaches of analysis are presented for each scheme. For exponential job length distribution, the analysis is done using the mean field approach and for more general job length distributions the analysis is carried out assuming an asymptotic independence property. Analytical expressions to compute mean sojourn time of jobs are found for both schemes. Asymptotic insensitivity of the schemes to the type of job length distribution is established. Numerical results are presented to validate the theoretical results and to show that, unlike the homogeneous scenario, the power-of-two type schemes considered in this paper may not always result in better behaviour in terms of the mean sojourn time of jobs.
2012 IEEE Global Communications Conference (GLOBECOM), 2012
ABSTRACT Multi-packet reception (MPR), in which a receiver can decode multiple simultaneous trans... more ABSTRACT Multi-packet reception (MPR), in which a receiver can decode multiple simultaneous transmissions, significantly improves the uplink throughput of wireless local area networks (WLANs). However, the medium access control (MAC) layer must be redesigned to encourage, and not avoid, simultaneous transmissions. Asynchronous MPR MAC protocols, in which nodes independently access the channel so long as the number of ongoing transmissions is less than a threshold, are promising solutions for enabling MPR in IEEE 802.11-based WLANs. In this paper, we highlight the problem of acknowledgment (ACK) delays that arises in asynchronous MPR when multiple nodes transmit in succession without the channel becoming idle. We propose a novel asynchronous MAC protocol that reduces the ACK delays, increases throughput, and retains the distributed nature of the 802.11 distributed coordination function (DCF). An accurate renewal theoretic fixed-point analysis that leads to general analytical expressions for the saturation throughput is also developed.
2008 Third International Conference on Digital Information Management, 2008
This paper presents a simple mathematical analysis of some features of the Harmony Search algorit... more This paper presents a simple mathematical analysis of some features of the Harmony Search algorithm (HS). HS is a recently developed derivative-free optimization algorithm, which draws inspiration from the musical process of searching for a perfect state of harmony. This work analyses the evolution of the population-variance over successive generations in HS and thereby draws some important conclusions regarding the explorative power of HS. Experimental results have been provided to validate the theoretical treatment. A simple modification of the classical HS has been proposed in the light of the mathematical analysis undertaken here.
IEEE Transactions on Wireless Communications, 2000
ABSTRACT Multi-packet reception (MPR) promises significant throughput gains in wireless local are... more ABSTRACT Multi-packet reception (MPR) promises significant throughput gains in wireless local area networks (WLANs) by allowing nodes to transmit even in the presence of ongoing transmissions in the medium. However, the medium access control (MAC) layer must now be redesigned to facilitate — rather than discourage — these overlapping transmissions. We investigate asynchronous MPR MAC protocols, which successfully accomplish this by controlling the node behavior based on the number of ongoing transmissions in the channel. The protocols use the backoff timer mechanism of the distributed coordination function, which makes them practically appealing. We first highlight a unique problem of acknowledgment delays, which arises in asynchronous MPR, and investigate a solution that modifies the medium access rules to reduce these delays and increase system throughput in the single receiver scenario. We develop a general renewal-theoretic fixed-point analysis that leads to expressions for the saturation throughput, packet dropping probability, and average head-of-line packet delay. We also model and analyze the practical scenario in which nodes may incorrectly estimate the number of ongoing transmissions.
IEEE Transactions on Systems, Man, and Cybernetics, Part B (Cybernetics), 2000
The theoretical analysis of evolutionary algorithms is believed to be very important for understa... more The theoretical analysis of evolutionary algorithms is believed to be very important for understanding their internal search mechanism and thus to develop more efficient algorithms. This paper presents a simple mathematical analysis of the explorative search behavior of a recently developed metaheuristic algorithm called harmony search (HS). HS is a derivative-free real parameter optimization algorithm, and it draws inspiration from the musical improvisation process of searching for a perfect state of harmony. This paper analyzes the evolution of the populationvariance over successive generations in HS and thereby draws some important conclusions regarding the explorative power of
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Papers by Arpan Mukhopadhyay