Jorge Amaya

Application of a Particle Swarm Algorithm to the Capacitated Open Pit Mining Problem

In the Capacitated Open Pit Mining Problem, we consider the sequential extraction of blocks in order to maximize the total discounted profit under an extraction capacity during each period of the horizon. We propose a formulation closely related to the Resource-Constrained Project Scheduling Problem (RCPSP) where the genotype representation of the solution is based on a priority value encoding. We use a GRASP procedure to generate an initial population (swarm) evolving according to a Particle Swarm Procedure to search the feasible domain of the representations. Numerical results are introduced to analyse the impact of the different parameters of the procedures.

Duality for inexact linear programming problems

We propose a notion of dual problem for the inexact linear programming problem in general form. Weak and strong duality relations are discussed

Duality for inexact semi-infinite linear programming

The aim of this work is to generalize strong duality theorems for inexact linear programming and to derive duality results for inexact semi-infinite programming problems. We give a detailed proof of the general result, using the Dubovitskii–Milyutin approach. The last section contains applications to inexact problems and a few comments for further developments.

Strong duality for inexact linear programming

In this paper, we apply the Dubovitskii-Milyutin approach to derive strong duality theorems for inexact linear programming problems. Inexact linear programming deals with the standard linear problem in which the data is not well known and it is supposed to lie in certain given convex sets. The case of parametric dependence of the data is particularly analyzed and relations with semi-infinite and semi-definite programming are also commented.

A continuous framework for open pit mine planning

This paper proposes a new mathematical framework for the open pit mine planning problem, based on continuous functional analysis. The main challenge for engineers is to determine a sequence of nested profiles maximizing the net present value of the mining operation. The traditional models for this problem have been constructed by using binary decision variables, giving rise to large-scale combinatorial and Mixed Integer Programming problems. Instead, we use a continuous approach which allows for a refined imposition of slope constraints associated with geotechnical stability. The framework introduced here is posed in a suitable functional space, essentially the real-valued functions that are Lipschitz continuous on a given two dimensional bounded region. We derive existence results and investigate qualitative properties of the solutions.

Component based approach using OMNeT++ for train communication modeling

This paper reports on our experience in using OMNeT++ to develop a network simulator focused on railway environments. Common design problems are analyzed, making emphasis on radio communication models. Scalability issues are raised when modeling the large topologies that are associated with railway communications. Our conclusions point out that model reusability must be reinforced and that a component-based design must be adopted in order to build a tool for generating valuable performance results.

On the stability of linear systems with an exact constraint set

AbstractThis paper deals with the stability of the intersection of a given set

On the convergence of curvilinear search algorithms in unconstrained optimization

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