This research proposes a bi-level model for the mixed network design problem (MNDP). The upper level problem involves redesigning the current road links' directions, expanding their capacity, and determining signal settings at intersections to optimize the reserve capacity of the whole system. The lower level problem is the user equilibrium traffic assignment problem. By proving that the optima...

Scatter Search es un método metaheurístico para resolver problemas de optimización. Aunque fue originalmente introducido en los años setenta, recientemente es cuando ha sido probado en numerosos problemas difíciles con gran éxito. Pertenece a la familia de los llamados Algoritmos Evolutivos, los cuales se distinguen por estar basados en la combinación de un conjunto de soluciones. Aunque presen...

This paper presents a hybrid metaheuristic algorithm which is Harmony-Scatter Search (HSS). The HSS provides Scatter Search (SS) with random exploration for search space of problem and more of diversity and intensification for promising solutions. The SS and HSS have been tested on Traveling Salesman Problem. A computational experiment with benchmark instances is reported. The results demonstra...

The cutwidth minimization problem consists of finding a linear layout of a graph so that the maximum linear cut of edges is minimized. This NP-hard problem has applications in network scheduling, automatic graph drawing and information retrieval. We propose a heuristic method based on the Scatter Search (SS) methodology for finding approximate solutions to this optimization problem. This metahe...

Scatter search is an evolutionary method that has been successfully applied to hard optimization problems. The fundamental concepts and principles of the method were first proposed in the 1970s and were based on formulations, dating back to the 1960s, for combining decision rules and problem constraints. The combination strategy was devised with the belief that information could be exploited mo...

University exam timetabling refers to scheduling exams into predefined days, time periods and rooms, given a set of constraints. Exam timetabling is a computationally intractable optimization problem, which requires heuristic techniques for producing adequate solutions within reasonable execution time. For large numbers of exams and students, sequential algorithms are likely to be time consumin...

The feature selection problem in the field of classification consists of obtaining a subset of variables to optimally realize the task without taking into account the remainder variables. This work presents how the search for this subset is performed using the Scatter Search metaheuristic and is compared with two traditional strategies in the literature: the Forward Sequential Selection (FSS) a...

In this paper we present an algorithm to assign proctors to exams. This NPhard problem is related to the generalized assignment problem with multiple objectives. The problem consists of assigning teaching assistants to proctor final exams at a university. We formulate this problem as a multiobjective integer program (IP) with a preference function and a workload-fairness function. We then consi...

An objective function often is only a rough approximation of the actual goals of the organization and its stakeholders. Consequently, an optimal solution may be no more interesting than other solutions that provide good values. Beyond this, a set of “good” solutions whose members have diverse characteristics can be significantly more valuable for practical analysis and planning than any single,...

Abs t r ac t -We address the problem of board-level multiterminal net assignment in FPGA-based logic emulation. We present a novel mathematical model for this problem. A powerful metaheuristic approach, called scatter search, is adopted. Effective heuristics are incorporated for accelerating the optimization search process. Experimental results demonstrate the promising performance of our appro...