Forward-chaining heuristic search is a well-established and popular paradigm for planning. It is, however, characterised by two key weaknesses. First, search is guided by a domain-independent heuristic which although applicable in a wide range of domains, can often give poor guidance. Second, the metaheuristics used to control forward-chaining planning are often weak, using simple local-search ...

The problem of assigning gates to arriving and departing flights is one of the most important problems in airport operations. We take into account the real multi-criteria nature of the problem by optimizing a total of nine gate allocation objectives that are oriented both on convenience for airport/airline services and passenger comfort. As far as we are aware, this is the largest number of obj...

Static-list scheduling algorithms are constructive heuristics with a low complexity and highly useful for design space exploration. In this paper, we present a static-list scheduling algorithm that incorporates a novel topological clustering heuristic. Based on the clustering heuristic, we have developed a simple operation selection function and a combination of two cost functions to determine ...

The Technician Routing and Scheduling Problem (TRSP) consists in routing staff to serve requests for service, taking into account time windows, skills, tools, and spare parts. Typical applications include maintenance operations and staff routing in telecoms, public utilities, and in the health care industry. In this paper, we present a formal definition of the TRSP, discuss its relation with th...

In this paper we develop an adaptive memory programming method for solving the capacitated vehicle routing problem called Solutions’ Elite PArts Search (SEPAS). This iterative method, .rst generates initial solutions via a systematic diversi.cation technique and stores their routes in an adaptive memory. Subsequently, a constructive heuristic merges route components (called elite parts) from th...

This article considers the problem of scheduling preemptive open shops to minimize total tardiness. The problem is known to be NP-hard. An efficient constructive heuristic is developed for solving large-sized problems. A branch-and-bound algorithm that incorporates a lower bound scheme based on the solution of an assignment problem as well as various dominance rules are presented for solving me...

The set covering problem (SCP) is central in a wide variety of practical applications for which finding good feasible solutions quickly (often in real-time) is crucial. Surrogate constraints normalization is a classical technique used to derive appropriate weights for surrogate constraint relaxations in mathematical programming. This framework remains the core of the most effective one-pass con...

We introduce the minimum labelling spanning bi-connected subgraph problem (MLSBP) replacing connectivity by bi-connectivity in the well known minimum labelling spanning tree problem (MLSTP). A graph is bi-connected if, for every two vertices, there are, at least, two vertex-disjoint paths joining them. The problem consists in finding the spanning bi-connected subgraph or block with minimum set ...

Order picking deals with the retrieval of articles from their storage locations in order to satisfy customer requests. A major issue in manual order picking systems concerns of the transformation and consolidation of customer orders into picking orders (order batching). In practice, customer orders have to be completed by certain due dates in order to avoid delay in the shipment to customers or...

This paper studies a new generalization of the regular permutation flowshop scheduling problem (PFSP) referred to as the distributed permutation flowshop scheduling problem or DPFSP. Under this generalization, we assume that there are a total of identical factories or shops, each one with machines disposed in series. A set of n available jobs have to be distributed among the factories and then ...