The travelling salesman problem (TSP) is one of combinatorial optimization problems huge importance to practical applications. However, the TSP in its “pure” form may lack some essential issues for a decision maker—e.g., time-dependent conditions. Among those shortcomings, there also possibility not visiting nodes network—e.g., thanks existence more cost-efficient means transportation. In this ...

In this paper we study the problem of finding placement tours for pick-and-place robots, also known as the printed circuit board assembly problem with m positions on a board, n bins containing m components and n locations for the bins. In the standard model where the working time of the robot is proportional to the distances travelled, the general problem appears as a combination of the travell...

In this work, we study two special cases of the metric Travelling Salesman Problem, Graph TSP and TSP(1,2). At rst, we show that dense instances of TSP(1,2) and Graph TSP are essentially as hard to approximate as general instances of TSP(1,2). Next, we present an NC algorithm for TSP(1,2) that produces a tour of length at most n plus the cardinality of the Maximum Independent Set of the input g...

Abstract This paper introduces a computational method for generating metric Travelling Salesman Problem (TSP) instances having large integrality gap. The is based on the solution of an integer programming problem, called IH-OPT, that takes as input fractional Subtour Elimination (SEP) TSP instance and computes gap larger than or equal to first instance. decision variables IH-OPT are entries cos...

This work aims at selecting the operating conditions and designing screws that optimize the performance of single-screw and co-rotating twin-screw extruders, which are machines widely used by the polymer processing industry. A special MOEA, denoted as Reduced Pareto Set Genetic Algorithm, RPSGAe, is presented and used to solve these multiobjective combinatorial problems. Twin screw design is fo...

We introduce a new method to estimate the Java object activity in a distributed context of irregular applications. This method uses an observation mechanism which is itself a part of a more global load balancing system. It predicts the tendencies of the communication between the objects of the distributed application. To illustrate the behaviour of this mechanism we applied it to the “Travellin...

In ad hoc wireless networks, nodes are typically powered by batteries. Therefore saving energy has become a very important objective, and different algorithms have been proposed to achieve power efficiency during the routing process. Directional antenna has been used to further decrease transmission energy as well as to reduce interference. In this paper, we discuss five algorithms for routing ...

In the Traveling Salesman Problem (TSP), a salesman wants to visit set of cities and return home. There is cost $$c_{ij}$$ traveling from city i j, which same in either direction for Symmetric TSP. The objective each exactly once, minimizing total travel costs. Graphical TSP, may be visited more than necessary on sparse graph. We present new integer programming formulation TSP requiring only tw...