iran is one f the biggest oil producer and exporter of the world. due to the special administrative and constitutional structure of the country, i.e. economic, social and political reasons, the government budget and revenues depend heavily on oil exports. the aim of this article is to suggest a theoretical proposal on the optimum level of non-oil exports such that it will clear up the idea of e...

The increase number of mobile users in wireless environment affects query access time substantially. To minimise the query access time, one possible way is to employ data broadcasting strategy. In this paper, we propose cost models for both query access time over broadcast channel and on-demand channel. We examine the cost models to find optimum number of broadcast items in a channel while util...

Constraint logic programming with linear constraints over nite integer domains, CLP(FD), has been established as a practical tool for solving discrete scheduling problems. A scheduling problem can be suitably modelled in terms of a set of constraints. To generate a solution, however, a search is neccessary, and the choice of an adequate strategy is a problem. The goal of our investigations is t...

One of the most complicated and time-consuming process in ship production is to determine the optimum route of piping. The automatic system to generate optimum collision free routes for pipes is presented in this paper. In the past, research has been primarily focused on the use of only deterministic or only nondeterministic optimization techniques to find the optimal route. In this paper, the ...

This paper summarizes the implementation and performance of Nondominated Sorting Genetic algorithm (NSGA-II) [2] for feature selection of remotely sensed hyperspectral imagery. Two step processes have been followed. In first step, a feature subset is selected with optimum spectral and texture information content resulting in a smaller space to be searched in the next step. In the second step, a...

The basic ant colony algorithm is easy to fall into local optimum and its convergent speed is slow for solving multiple QoS multicast routing problems. Therefore, a crowding ant colony algorithm is proposed in this paper to solve the problems. Crowded degree in artificial fish swarm algorithm is used to adjust nodes transition strategy dynamically according to the congestion of nodes. Stagnatio...

We present two models for phenotypic-dependent interspecific competition. In both cases the survivorship of individuals of one population depends on the entire phenotypic distribution of the other species. The first model considers a continuously varying metric trait, with assortative or random mating; the second model examines a character controlled by two alleles at a single locus. Pursuing t...

This paper attempts to improve the computational efficiency of the well known particle swarm optimization (PSO) algorithm for tackling discrete sizing optimization problems of steel frame structures. It is generally known that, in structural design optimization applications, PSO entails enormously time-consuming structural analyses to locate an optimum solution. Hence, in the present study it i...