Pub. online:15 Oct 2020Type:Research ArticleOpen Access
Volume 31, Issue 4 (2020), pp. 681–706
This paper deals with the two-stage transportation problem with fixed charges, denoted by TSTPFC. We propose a fast solving method, designed for parallel environments, that allows solving real-world applications efficiently. The proposed constructive heuristic algorithm is iterative and its primary feature is that the solution search domain is reduced at each iteration. Our achieved computational results were compared with those of the existing solution approaches. We tested the method on two sets of instances available in literature. The outputs prove that we have identified a very competitive approach as compared to the methods than one can find in literature.
Pub. online:1 Jan 2015Type:Research ArticleOpen Access
Volume 26, Issue 3 (2015), pp. 407–417
The concept of stratified graph introduces some method of representation which can be embedded with an interpretation mechanism in order to obtain objects from some knowledge domain based on the considered symbolic graph-based representations. As it was defined in the literature, the inference process uses the paths of the stratified graphs, an order between the elementary arcs of a path and some results of universal algebras. The order is defined by considering a structured path instead of a regular path. In a previous paper the concept of system of knowledge representation was defined. It includes a stratified graph G, a partial algebra Y of objects, an injective mapping that embeds the nodes of G into objects of Y and a set of algorithms that takes pairs of objects from Y to get some other object of Y. In this paper the inference process defined for such a system of knowledge considers the interpretation of the symbolic elements of a stratified graph as formal language constructions. The concepts introduced in this paper can initiate a possible research line concerning the automatic generation mechanism for formal languages.