We approximate the objective function of the fixed charge network flow problem (FCNF) by a piecewise linear one, and construct a concave piecewise linear network flow problem (CPLNF). A proper choice of parameters in the CPLNF problem guarantees the equivalence between those two problems. We propose a heuristic algorithm for solving the FCNF problem, which requires solving a sequence of CPLNF p...

We consider the single-commodity single-origin fixed-charge network flow problem (SSFNP) defined on a directed network G = (V,A), where V is the node set and A is the arc set, with each arc a represented by the ordered pair of head and tail nodes (h(a), t(a)). The node set includes a single origin (with no incoming arc), multiple destinations (with no outgoing arc) and transshipment nodes (with...

Network problems concern the selection of arcs in a graph in order to satisfy, at minimum cost, some flow requirements, usually expressed in the form of node–node pair demands. Benders decomposition methods, based on the idea of partitioning of the initial problem to two sub-problems and on the generation of cuts, have been successfully applied to many of these problems. This paper presents a n...

In highly adaptive irregular problems such as many Particle-In-Cell (PIC) codes and Direct Simulation Monte Carlo (DSMC) codes, data access patterns may vary from time step to time step. This uctuation may hinder eecient utilization of distributed memory parallel computers because of the resulting overhead for data redistribution and dynamic load balancing. To eeciently parallelize such adap-ti...

objectives: the needs and problems of students with physical-motor disabilities should be properly identified in order to solve them. the main purpose of this research was to determine the needs and problems of iranian male students with physical-motor disabilities in the education and employment dimensions.  methods: this was a descriptive study. all the male students with physical-motor disab...