Eitan Altman

Asymptotic Optimization of a Nonlinear Hybrid System Governed by a Markov Decision Process

We consider in this paper a continuous time stochastic hybrid control system with finite time horizon. The objective is to minimize a nonlinear function of the state trajectory. The state evolves according to a nonlinear dynamics. The parameters of the dynamics of the system may change at discrete times

RADIO PLANNING IN MULTIBEAM GEOSTATIONARY SATELLITE NETWORKS

l\epsilon

SLOT ALLOCATION IN A TDMA SATELLITE SYSTEM: SIMULATED ANNEALING APPROACH

,

Dynamic Admission Game into an M/M/1 Queue

l=0,1,...

Dynamic Games for Analyzing Competition in the Internet and in On-Line Social Networks

, according to a controlled Markov chain which has finite state and action spaces. Under the assumption that

Finite Improvement Property in a Stochastic Game Arising in Competition over Popularity in Social Networks

\epsilon

An asymptotic simplex method for parametric linear programming

is a small parameter, we justify an averaging procedure allowing us to establish that our problem can be approximated by the solution of some deterministic optimal control problem.

Queueing analysis of simple FEC schemes for 1P Telephony

We consider the problem of how a geostationary satellite should assign bandwidth to several service providers (operators) so as to meet some minimum requirements, on one hand, and to perform the allocation in a fair way, on the other hand. In the paper, we firstly address practical issues (such as integrity constraints), whereafter we provide a computational method for obtaining an optimal fair allocation in polynomial time taking the practical issues into account.

The effect of router buffer size on the TCP performance

We consider in this paper the uplink slot assignment problem in a multi-spot geostationary satellite. Radio interference impose constraints on the slots that can simultaneously be assigned in difierent cells that have the same frequency. The problem is shown to be an NP-complete one, which motivates us to search for a heuristic solution approach. We describe here a heuristic solution based on simulated annealing. We further investigate how to improve the performance of the simulated annealing and the rate of convergence of the annealing. Numerical experimentations are provided to test our proposed improvements.

Cooperative and Non-Cooperative Control in IEEE 802.11 WLANs

Around 50 years ago, P. Naor has derived the optimal social and individual admission rules to an M/M/1 queue. In both cases, the optimal policies were identified to be of a pure threshold type: admit if and only if the number queued upon arrival is below some threshold. The value of the threshold in the individual optimal case was shown to be larger than the one for the social optimal criterion. We make the observation that admitting according to a threshold policy requires only the information of whether the queue is above or below a threshold. We call these “red” and “green” light, respectively, associated with a threshold, say L. The question that we pose in this paper is: what happens if one restricts to the above information pattern but let the threshold level L be chosen by the system which signals to arrivals whether the queue is above or below the threshold. Can one find a choice of a threshold that will induce an equilibrium that performs better than in the case that full information is available? We also examine the question of what is the threshold that maximizes the revenue for the queue. We show that the choice of threshold that maximizes the system’s performance at equilibrium is the same as under the full information case if the service in the queue follows the FIFO discipline.