Nonlinear non-stationary large scale (NNLS) systems such as power system networks, telecommunication networks, financial and transportation systems are difficult to control and manage. Mathematical models of such systems are typically derived based on linear techniques, and wide margins of safety are allowed in order to ensure stable operation. In the era of a deregulated electricity industry, ...

Today’s society relies greatly upon an array of complex national and international infrastructure networks, such as transportation, utilities, telecommunication, and even financial networks. While modeling and simulation tools have provided insight into the behavior of individual infrastructure networks, a far less understood area is that of the interrelationships between multiple networks. Spe...

A typical polling system consists of a number of queues, attended by a single server in a fixed order. The vast majority of papers on polling systems focusses on Poisson arrivals, whereas very few results are available for general arrivals. The current study is the first one presenting simple closed-form approximations for the mean waiting times in polling systems with renewal arrival processes...

—It is a well-known fact that today a nation's telecommunication networks, critical infrastructure, and information systems are vulnerable to growing number of attacks in cyberspace. Cyber space contains very different problems involving various sets of threats, targets and costs. Cyber security is not only problem of banking, communication or transportation. It also threatens core systems of a...

Mathematical Programming (MP) is a technique for finding the minimum or the maximum of (i.e., optimizing) a given function, referred to as the objective function, by systematically choosing real or integer values of the function’s variables from a value domain defined by a set of constraints. We are interested in MP problems in which (1) the objective function is linear, and (2) all constraints...

Given a graph G with a label (color) assigned to each edge (not necessarily properly) we look for an hamiltonian cycle of G with the minimum number of different colors. The problem has several applications in telecommunication networks, electric networks, multimodal transportation networks, among others, where one aims to ensure connectivity or other properties by means of limited number of dif...

In transportation and telecommunication systems, the performance of the underlying network can often be improved by upgrading some of the arcs in the network. If an arc is upgraded, the travel time along this arc is reduced by a discount factor α, 0 ≤ α < 1. With respect to different minimax network objectives, we define a series of problems that involve finding the best q arcs in a network to ...

In the context of logistics and transportation, this paper discusses how simheuristics can be extended by adding a fuzzy layer that allows us to deal with complex optimization problems both stochastic uncertainty. This hybrid approach combines simulation, metaheuristics, logic generate near-optimal solutions large scale NP-hard typically arise in many transportation activities, including vehicl...

Purpose – The aim of this study is to examine relation between employees’ participation in the organizations decisions making and their psychological empowerment in Iran Telecommunication Company subsidiary of Mazanderan Province. Design / methodology /approach- 250 employees from the Iran Telecommunication Company subsidiary of Mazanderan Province participated in this study. A Spearman's cor...

purpose – the aim of this study is to examine relation between employees’ participation in the organizations decisions making and their psychological empowerment in iran telecommunication company subsidiary of mazanderan province. design / methodology /approach- 250 employees from the iran telecommunication company subsidiary of mazanderan province participated in this study. a spearman's cor...