The Gale-Hoffman inequalities characterize feasible external flow in a (capacitated) network. Among these inequalities, those that are redundant can be identified through a simple arc-connectedness criterion.

this paper examines the effect of the poor road transportation network on crop production in one of the rural agrarian local government of kwara state, nigeria. a well-structured interview schedule was conducted to elicit information from 120 crop farmers using a two-stage sampling technique. findings from the study revealed that the poor road transportation network in their area had led to a r...

This paper presents a routing optimization model for wide range of waste collection problems which allows multiple depots with homogeneous, capacitated vehicles, intermediate stops at processing facilities, and pick-ups per location. By minimizing vehicle investment costs, the estimates total transportation costs given network design volumes to be collected different demand points. The number f...

This paper focuses on a generic model for service network design, which includes asset positioning and utilization through constraints on asset availability at terminals. We denote these relations as “design-balance constraints” and focus on the design-balanced capacitated multi-commodity network design model, a generalization of the capacitated multi-commodity network design model generally us...

In this article we present an algorithm for converting a network problem with several sources and several sinks including several transfer nodes and condition of supplying the demand of any sink from a particular source to the transportation problem.  Towards this end, and considering the very special structure of transportation algorithm, after implementing the shortest path algorithm or ...

This paper presents a multi-objective mixed-integer non-linear programming model for congested multiple-server discrete facility location problem with uniformly distributed demands along the network edges. Regarding capacity of each and maximum waiting time threshold, developed aims to determine number locations established facilities their corresponding assigned servers such that traveling dis...

Flow cover inequalities are among the most effective valid inequalities for capacitated fixed-charge network flow problems. These valid inequalities are based on implications for the flow quantity on the cut arcs of a two-partitioning of the network, depending on whether some of the cut arcs are open or closed. As the implications are only on the cut arcs, flow cover inequalities can be obtaine...

We consider two types of path selection problems for arc capacitated network. Given an arc capacitated network and a set of commodities, one problem is to find a subset of commodities to be routed and an assignment of them to the paths so that profit is maximized. The other problem is to route all given commodities in the network so that cost is minimized. Bifurcation of flow is not allowed in ...

in this paper, a novel multi-objective bus stop location model is proposed, which considers not only the coverage of demand and minimization of access time but also the necessities of suitable stops for transit network design phase. three objective functions are considered including minimizing (i) sum of the total access distance (time), (ii) the weighted combination of stops, and (iii) the num...