Many engineering design problems must optimize multiple objectives. While many objectives are explicit and can be mathematically modeled, some goals are subjective and cannot be included in a mathematical model of the optimization problem. A set of alternative non-dominated fronts that represent multiple optima for problem solution can be identified to provide insight about the decision space a...

A hybrid local-global and deterministic-evolutionary strategy is proposed for the reduction of objective function calls when Pareto Optimal front approximation is considered in multiobjective optimization problems arising from electromagnetic shape design. Both analytical and real-life test cases are discussed stressing the key-point of switching criteria.

Diversity maintenance of solutions is an essential part in multi-objective optimization. Existing techniques are suboptimal either in the sense of obtained distribution or execution time. This paper proposes an effective and relatively fast method for pruning a set of non-dominated solutions. The proposed method is based on a crowding estimation technique using nearest neighbors of solutions in...

In a previous paper we have written down equations describing steady-state, optically thin, advection-dominated accretion onto a Kerr black hole (Gammie & Popham (1997), hereafter Paper I). In this paper we survey the numerical solutions to these equations. We find that the temperature and density of the gas in the inner part of the accretion flow depend strongly on the black hole spin paramete...

A haptotaxis-dominated model of cell invasion is considered for small cell diffusion and fast protease adjustment to the cell–collagen matrix interaction. A simplified limit model has travelling wave cell invasion profiles that are blunt, that is end with a ‘shock-like’ step, and that evolve stably from initial data that lie to one side of some initial plane. In common with diffusiondominated s...

We consider the question: given a multi-objective optimization problem and a search algorithm for generating solutions to it, which non-dominated solutions should be kept, assuming at most N of them can be stored at any time? One would like the points (the images of the solutions in the objective space) stored to form a well-distributed approximation of the Pareto front of the sequence of point...

In this article, we utilize spline wavelets to establish an adaptive multilevel numerical scheme for timedependent convection-dominated diffusion problems within the frameworks of Galerkin formulation and Eulerian-Lagrangian localized adjoint methods (ELLAM). In particular, we shall use linear Chui-Quak semiorthogonal wavelets, which have explicit expressions and compact supports. Therefore, bo...

the aim of this paper is to present an efficient method for a rail freight car fleet sizing problem. this problem is modeled mathematically as a multi-period, dynamic and multi-objective, in which the rail freight wagons are assumed to be heterogeneous. demands for different wagons and all travel times are assumed deterministic. in order to increase the utilization of the available wagons in th...

The problem of maximal hub covering as a challenging problem in operation research. Transportation programming seeks to find an optimal location of a set of hubs to reach maximum flow in a network. Since the main structure's parameters of the problem such as origin-destination flows, costs and travel time, change periodically in the real world applications, new issues arise in handling it. In t...