Given an increase in consumer demand for product quality, companies need to continually improve their means of production. The use computational resources assists choose ordering system that best suits reality. In this sense, the present study aims analyze and compare performance Paired-cell Overlapping Loops Cards with Authorization (POLCA) system, according pre-established parameters a real a...

in this paper, a robust model presented is developed for hub covering flow problem in which hubs have capacity. this problem has two objective functions converting to a single-objective problem by using weighting method. firstly, the problem will be formulated in a certain case. then, by considering the demand as a non-random variable, it will be modeled by robust optimization. finally, by usin...

this paper presents a fuzzy decision-making approach to deal with a clustering supplier problem in a supply chain system. during recent years, determining suitable suppliers in the supply chain has become a key strategic consideration. however, the nature of these decisions is usually complex and unstructured. in general, many quantitative and qualitative factors, such as quality, price, and fl...

in recent years, soft computing methods have generated a large research interest. the synthesis of the fuzzy logic and the evolutionary algorithms is one of these methods. a particular evolutionary algorithm (ea) is differential evolution (de). as for any ea, de algorithm also requires parameters tuning to achieve desirable performance. in this paper tuning the perturbation factor vector of de ...

We study hardness of approximating several minimaximal and maximinimal NP-optimization problems related to the minimum linear ordering problem (MINLOP). MINLOP is to find a minimum weight acyclic tournament in a given arc-weighted complete digraph. MINLOP is APX-hard but its unweighted version is polynomial time solvable. We prove that, MIN-MAX-SUBDAG problem, which is a generalization of MINLO...

In this paper we consider a two-stage ordering problem with a buyer’s minimum commitment quantity contract. Under the contract the buyer is required to give a minimum-commitment quantity. Then the manufacturer has the obligations to supply the minimum-commitment quantity and to provide a shortage compensation policy to the buyer. We formulate a dynamic optimization model to determine the manufa...

This paper studies the computation of order up to levels for a stochastic programming inventory problem of a perishable product. Finding a solution is a challenge as the problem enhances a perishable product, fixed ordering cost and non-stationary stochastic demand with a service level constraint. An earlier study [6] derived order-up-to values via an MILP approximation. We consider a computati...

s of the Presentations Solving inconsistencys preserving the zero-structure Paula Amaral, Joaquim Júdice and Hanif Sherali, University of Coimbra In this talk we describe an nonlinear optimization model for correcting an inconsistent linear system. By correction we mean a perturbation of both the matrix of coefficients and right-hand-side of the linear system of inequalities. Inconsistency of a...

We show, under some assumption on the signature, that the 9 8 fragment of the theory of a lexicographic path ordering is undecidable, both in the partial and in the total precedence cases. Our result implies in particular that the simpliication rule of ordered completion is undecidable.

the markowitz’s optimization problem is considered as a standard quadratic programming problem that has exact mathematical solutions. considering real world limits and conditions, the portfolio optimization problem is a mixed quadratic and integer programming problem for which efficient algorithms do not exist. therefore, the use of meta-heuristic methods such as neural networks and evolutionar...