Local search algorithms for combinatorial optimization problems are in general of pseudopolynomial running time and polynomial-time algorithms are often not known for finding locally optimal solutions for NP-hard optimization problems. We introduce the concept of epsilon-local optimality and...

We consider neighborhood search defined on combinatorial optimization problems. Suppose that N is a neighborhood for combinatorial optimization problem X. We say that N' is LO-equivalent (locally optimal) to N if for any instance of X, the set of locally optimal solutions with respect to N and...

In this paper, we study dynamic shortest path problems that determine a shortest path from a specified source node to every other node in the network where arc travel times change dynamically. We consider two problems: the minimum time walk problem and the minimum cost walk problem. The minimum...

This paper presents a very large scale neighborhood (VLSN) search algorithm for the capacitated facility location problem with single-source constraints. The neighborhood structures are induced by customer multi-exchanges and by facility moves. We consider both single-customer multi-exchanges,...

The fleet-assignment model (FAM) for an airline assigns fleet types to the set of flight legs that satisfies a variety of constraints and minimizes the cost of the assignment. A through connection at a station is a connection between an arrival flight and a departure flight at the station, both...