in many real world assembly line systems which the work-piece is of large size more than one worker work on the same work-piece in each station. this type of assembly line is called multi-manned assembly line (mal). in the classical multi-manned assembly line balancing problem (malbp) the objective is to minimize the manpower needed to manufacture one product unit. apart from the manpower, othe...

In this research, we investigate a three-stage supply chain with one supplier, several manufacturers and multiple retailers where the supplier provides a common raw material to each manufacturer, who in turn uses a single stage production facility to convert it into final products that are delivered at fixed lot sizes to retailers. An integrated economic procurement, production, and delivery mo...

The Linear Ordering Problem (LOP) is an NP-hard combinatorial optimization problem that arises in a variety of applications and several algorithmic approaches to its solution have been proposed. However, few details are known about the search space characteristics of LOP instances. In this article we develop a detailed study of the LOP search space. The results indicate that, in general, LOP in...

The Robust Coloring Problem (RCP) is a generalization of the well-known Graph Coloring Problem where we seek for a solution that remains valid when extra edges are added. The RCP is used in scheduling of events with possible last-minute changes and study frequency assignments of the electromagnetic spectrum. This problem has been proved as NP-hard and in instances larger than 30 vertices, meta-...

This paper investigates a capacitated planar location-allocation problem with facility fixed cost. A zonebased fixed cost which consists of production and installation costs is considered. A nonlinear and mixed integer formulation is first presented. A powerful three stage Cross Entropy meta-heuristic with novel density functions is proposed. In the first stage a covering location problem provi...

This article addresses a challenging industrial problem known as the unrelated parallel machine scheduling (UPMSP) with sequence-dependent setup times. In UPMSP, we have set of machines and group jobs. The goal is to find optimal way schedule jobs for execution by one several available machines. UPMSP has been classified an NP-hard optimisation and, thus, cannot be solved exact methods. Meta-he...

Many numerical computations reported in the literature show an only small diierence between the optimal value of the one-dimensional cutting stock problem (1CSP) and that of its corresponding linear programming relaxation. Moreover, theoretical investigations have proven that this difference is smaller than 2 for a wide range of subproblems of the general 1CSP. In this paper we give a branch&bo...