We solve the vertex p-centre problem optimally using an exact method that considers both upper and lower bounds as part of its search engine. Tight upper bounds are generated quickly via an efficient three-level heuristic, which are then used to derive potential ‘lower bounds’ accordingly. These two pieces of information when used together make our chosen exact method more efficient at obtaining optimal solutions relatively quickly. The proposed implementation produced excellent results when tested on the OR Library data set.

This paper is concerned with the optimal control of a production inventory system with time-varying deteriorating items. It is assumed that the deterioration rate follows the two parameters generalized exponential distribution. The continuous review policy is investigated. The optimality conditions are derived using Pontryagin maximum principle. The optimal total cost, the optimal inventory level, and the optimal production are derived. The sensitivity analysis of the system will be analyzed against the monetary and non-monetary parameters.

In this paper we will discuss the stochastic analysis of a three state semi-Markov reliability model. Maximum likelihood procedure will be used to obtain the estimators of the parameters included in this reliability model. Based on the assumption that the lifetime and repair time of the system units are generalized linear failure rate random variables, the reliability function of this system is obtained. Also, the distribution of the first passage time of this system will be derived. Some important special cases are discussed.

We present an efficient metaheuristic based on Simulated Annealing
for solving the p-Median problem. These ideas are tested on the well
known OR-Lib set of problems with excellent results

This paper studies the chaos and control of a continuous time food