the heterogeneous fixed fleet open vehicle routing problem (hffovrp) is one of the most significant extension problems of the open vehicle routing problem (ovrp). the hffovrp is the problem of designing collection routes to a number of predefined nodes by a fixed fleet number of vehicles with various capacities and related costs. in this problem, the vehicle doesn’t return to the depot after se...

a considerable problem in competitive trade world is choosing the best supply chain. as a result in much more serious circumstances of competitions looking for the best supplier for manufacturing, for preparing raw material, is very significant. meantime suppliers have different scenarios to be fulfilled, such as changing selection variables like lead-time, transportation cost and transportatio...

network location models comprise one of the main categories of location models. these models have various applications in regional and urban planning as well as in transportation, distribution, and energy management. in a network location problem, nodes represent demand points and candidate locations to locate the facilities. if the links network is unchangeably determined, the problem will be ...

It has been shown that mixed integer programming methods can e ectively support minimal model, stable model and well-founded model semantics for ground deductive databases. Recently, a novel approach called partial instantiation has been developed which, when integrated with mixed integer programming methods, can handle non-ground logic programs. The goal of this paper is to explore how this in...

This paper presents a novel, multi-objective model of a parallel machines scheduling problem that minimizes the number of tardy jobs and total completion time of all jobs. In this model, machines are considered as unrelated parallel units with different speeds. In addition, there is some precedence, relating the jobs with non-identical due dates and their ready times. Sequence-dependent setup t...

We consider a class of non-linear mixed integer programs with n integer variables and k continuous variables. Solving instances from this class to optimality is an NP-hard problem. We show that for the cases with k = 1 and k = 2, every optimal solution is integral. In contrast to this, for every k ≥ 3 there exist instances where every optimal solution takes non-integral values.

Constraint integer programming (CIP) is a novel paradigm which integrates constraint programming (CP), mixed integer programming (MIP), and satisfiability (SAT) modeling and solving techniques. In this paper we discuss the software framework and solver SCIP (Solving Constraint Integer Programs), which is free for academic and non-commercial use and can be downloaded in source code. This paper g...

Solving mixed integer linear programming (MILP) problems is a difficult task due to the parallel use of both integer and non-integer values. One of the most widely used solution is to solve the problem in the real space and they apply additional iteration steps (so-called cutting-plane algorithms or Gomory’s cuts) to narrow down the solution to the optimal integer solution. The ABS class of alg...

We consider the mixed integer version of bipartite vertex cover. This is equivalent to the mixed integer network dual model, recently introduced in [2], that generalizes several mixed integer sets arising in production planning. We derive properties of inequalities that are valid for the convex hull of the mixed integer bipartite covers by projecting an extended formulation onto the space of th...