In this paper, we handle the bottleneck problem of ZigBee-based networks. The bottleneck problem occurs at the nodes near the ZigBee coordinator since they have too many data to deliver during the data gathering process. This is a fundamental problem which reduces network throughput and prolongs transmission delay. A possible solution is to schedule each node’s transmission/receiving time prope...

Although the general class of most scheduling problems is NP-hard in worst-case complexity, in practice, domain-specific techniques frequently solve problems in much better than exponential time. Unfortunately, constructing special-purpose systems is a knowledge–intensive and time-consuming process that requires a deep understanding of the domain and problem-solving architecture. The goal of ou...

The paper deals with the problem of defining the territories for I68 sales agents of a German manufacturer of consumer goods. About 1400 postal areas constitute the basic geographical units. The problem is solved by means of a location-allocation approach involving a standard code of a primal network algorithm as well as a new heuristic for resolving split areas. Numerical results and the imple...

The Capacitated Arc Routing Problem (CARP) stands among the hardest combinatorial problems to solve or to find high quality solutions. This becomes even more true when dealing with large instances. This paper investigates methods to improve on lower and upper bounds of instances on graphs with over two hundred vertices and three hundred edges, dimensions that, today, can be considered of large ...

The RAND Corporation in the early 1950s contained “what may have been the most remarkable group of mathematicians working on optimization ever assembled” [6]: Arrow, Bellman, Dantzig, Flood, Ford, Fulkerson, Gale, Johnson, Nash, Orchard-Hays, Robinson, Shapley, Simon, Wagner, and other household names. Groups like this need their challenges. One of them appears to have been the traveling salesm...

We discuss the problem of large scale grammatical inference in the context of the Tenjinno competition, with reference to the inference of deterministic finite state transducers, and discuss the design of the algorithms and the design and implementation of the program that solved the first problem. Though the OSTIA algorithm has good asymptotic guarantees for this class of problems, the amount ...

We study a variant of dynamic vehicle routing problem with pickups and deliveries where a vehicle is allocated to each service (i.e., trip) request immediately upon the arrival of the request. Solutions to this problem can be characterized as dynamic policies that define how each customer is handled by operating a fleet of vehicles. Evaluation of such policies is beyond the grasp of analytical ...

In this paper, we are interested in routing vehicles to service large-scale emergencies, such as natural disasters and terrorist attacks. We first analyze the characteristics of the routing problem for large-scale emergencies. We then survey the stochastic Vehicle Routing Problems (VRPs) and some variants of VRPs that are relevant to emergency response. We propose and discuss a mathematical for...

This paper presents iterated local search and great deluge trajectory metaheuristics for the linear ordering problem (LOP). Both metaheuristics are based on the TREE local search method introduced in Sakuraba and Yagiura, 2010 (Efficient local search algorithms for the linear ordering problem, International Transactions in Operational Research 17, pp. 711–737) that is the only method ever appli...

This paper provides a means for comparing various computer codes for solving large scale mixed complementarity problems. We discuss inadequacies in how solvers are currently compared, and present a testing environment that addresses these inadequacies. This testing environment consists of a library of test problems, along with GAMS and MATLAB interfaces that allow these problems to be easily ac...