This paper introduces a new shortest path simplex pivot rule choosing a subset of non-basic arcs to simultaneously enter into the basis. The term multiple pivot for this operation is used. From this concept, a generic shortest path simplex algorithm with multiple pivots is described. In addition, a simplex multiple pivot rule is provided to design a shortest path simplex algorithm requiring O(n...

In the real word, there are many problems which have linear programming models and sometimes it is necessary to formulate these models with parameters of uncertainty. Many numbers from these problems are linear programming problems with fuzzy variables. Some authors considered these problems and have developed various methods for solving these problems. Recently, Mahdavi-Amiri and Nasseri (2007...

In this paper, we study the primal and dual simplex algorithms for the maximum flow problem. We show that aVny primal simplex algorithm for the maximum flow problem can be converted into a dual simplex algorithm that performs the same number of pivots and runs in the same time. The converse result is also true though in a somewhat weaker form.

for any agency dealing with the design of the water distribution network, an economic design will be an objective. in this research, central force optimization (cfo) and differential evolution (de) algorithm were used to optimize ismail abad water distribution network. optimization of the network has been evaluated by developing an optimization model based on cfo and de algorithm in matlab and ...

The evolution of encryption algorithms have led to the development of very complicated and highly versatile algorithms that sacrifice efficiency for better and harder to decrypt results. But by the application of a genetic schema to the encryption of data, a new structure can be created. Genetic methods and procedures are lethal in the way they handle and manipulate data. The RAmM algorithm use...

In this study, inventory planning in logistics networks of modular products is investigated in a multi-period and multi-echelon setting. It is shown that this optimization problem can be converted to another problem which is briefly called modular proportional flow problem. This later problem is a minimum cost network flow problem with side constraints. The whole network consists of several dis...