Jose M. Framinan

Review: Review and classification of hybrid flow shop scheduling problems from a production system and a solutions procedure perspective

In this paper, an extensive review of recently published papers on hybrid flow shop (HFS) scheduling problems is presented. The papers are classified first according to the HFS characteristics and production limitations considered in the respective papers. This represents a new approach to the classification of papers in the HFS environment. Second, the papers have been classified according to the solution approach proposed. These two classification categories give a comprehensive overview on the state of the art of the problem and can guide the reader with respect to future research work.

A review and classification of heuristics for permutation flow-shop scheduling with makespan objective

Stinson and Smith Cuv 1⁄4 Pm i1⁄42 jpiu pi 1;vj Cuv 1⁄4 Pm i1⁄42 fpiu pi 1;vg Cuv 1⁄4 Pm i1⁄42 jminfpiu pi 1;v þ minfðpi 1;v pi 2;vÞ; 0g; 0gj Cuv 1⁄4 Pm i1⁄42 jpiu pi 1;v þ minfðpi 1;v pi 2;vÞ; 0gj Cuv 1⁄4 Pm i1⁄42 fpiu pi 1;v þ minfðpi 1;v pi 2;vÞ; 0gg Cuv 1⁄4 Pm i1⁄42 maxfðpiu pi 1;vÞ; 0g þ 2jminfðpiu pi 1;vÞ; 0gj Widmer and Hertz Cuv 1⁄4 p1u þ Pm i1⁄41 ðm iÞjpiu pi 1;vj þ pmv Moccellin Cuv1⁄4UBX(m)uv, where UBX(1)uv1⁄4 0, and UBX(kþ 1)uv1⁄4max{0;UBX(k)uvþ (pkv pkþ 1,u)} Journal of the Operational Research Society (2005) 56, 351 r 2005 Operational Research Society Ltd. All rights reserved. 0160-5682/05

The CONWIP production control system: Review and research issues

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Approximative procedures for no-wait job shop scheduling

Since its introduction more than a decade ago, the CONstant Work In Process (CONWIP) production control system has received a great deal of attention from practitioners and researchers. In this paper, different contributions are reviewed according to three issues: operation, application, and comparison of Conwip. Referring to the operation of Conwip, some implementation decisions, such as lot sizing, have been overlooked, most studies being focused on card setting and job sequencing. Besides, no research has been conducted to show the relative importance of the different implementation decisions on the system performance. With respect to the application of Conwip, although it has been successfully implemented in many manufacturing environments, there are no studies to assess the impact of the manufacturing conditions on the performance of the system. Finally, most of the comparisons of Conwip with other production control systems suffer the lack of a unified framework for comparison where each system is tested under optimal parameter setting. The latter may explain partly the contradictory results found in the literature. It is believed that all these issues are relevant subjects for future research.

Different initial sequences for the heuristic of Nawaz, Enscore and Ham to minimize makespan, idletime or flowtime in the static permutation flowshop sequencing problem

In this article we consider the no-wait job shop problem with makespan objective. Based on a decomposition of the problem into a sequencing and a timetabling problem, we propose two local search algorithms. Extensive computational tests in which the algorithms compare favorably to the best existing strategies are reported. Although not specifically designed for that purpose, our algorithms also outperform one of the best no-wait flow shop algorithms in literature.

Comparison of heuristics for flowtime minimisation in permutation flowshops

The polynomial heuristic of Nawaz/Enscore/Ham (NEH) is one of the best heuristics to minimize makespan in static-deterministic permutation flowshop problems. The NEH approach consists of two steps: (1) the generation of an initial order of jobs with respect to an indicator value and (2) the iterative insertion of jobs into a partial sequence according to the initial order of step 1. We generalize this approach to minimization of makespan, idletime and flowtime, construct 177 different initial orders, and evaluate their performance in the NEH-insertion approach. Based on a comprehensive numerical study, we propose heuristics for all three objective functions that outperform significantly the compared literature-based heuristics.

Efficient heuristics for flowshop sequencing with the objectives of makespan and flowtime minimisation

In this paper, we address the problem of sequencing jobs in a permutation flow shop with the objective of minimising the sum of completion times or flowtime. This objective is considered to be relevant and meaningful for todays dynamic production environment, and therefore it has attracted the attention of researchers during the last years. As a result, a number of different types of heuristics have recently been developed, each one claiming to be the best for the problem. However, some of these heuristics have been independently developed and only partial comparisons among them exist. Consequently, there are no conclusive results on their relative performance. Besides, some of these types of heuristics are of a different nature and could be combined in order to obtain composite heuristics. In this paper, we first classify and conduct an extensive comparison among the existing heuristics. Secondly, based on the results of the experiments, we suggest two new composite heuristics for the problem. The subsequent computational experience shows these two heuristics to be efficient for the problem under consideration.

Architecture of manufacturing scheduling systems: Literature review and an integrated proposal

In this paper we analyse the performance of flowshop sequencing heuristics with respect to the objectives of makespan and flowtime minimisation. For flowtime minimisation, we propose the strategy employed by the NEH heuristic to construct partial solutions. Results show that this approach outperforms the common fast heuristics for flowtime minimisation while performing similarly or slightly worse than others which, on reward, prove to be much more CPU time-consuming. Additionally, the suggested approach is well balanced with respect to makespan and flowtime minimisation. Based on the previous results, two algorithms are proposed for the sequencing problem with multiple objectives – makespan and flowtime minimisation. These algorithms provide the decision maker with a set of heuristically efficient solutions such that he/she may choose the most suitable sequence for a given ratio between costs associated with makespan and those assigned to flowtime. Computational experience shows both algorithms to perform better than the current heuristics designed for the two-criteria problem.

Metrics for Bullwhip Effect Analysis

This paper deals with the development of customised and realistic manufacturing scheduling systems. More specifically, we focus onto a key element that may help driving their efficient design and implementation: i.e., the set of building blocks that should include a generic scheduling system and its interconnections, a set collectively known as the architecture of a system. To do so, we first analyse existing contributions on the topic together with papers describing different functional requirements of scheduling systems. These contributions are then discussed and classified, and a modular architecture for manufacturing scheduling systems is proposed. This proposal updates, extends and refines the well-known architecture proposed earlier by Pinedo and Yens [Pinedo, M.L., Yen, B.P.-C., 1997. On the design and development of object-oriented scheduling systems. Annals of Operations Research 70 (1), 359-378], and serves to integrate the different requirements identified in the literature review.

On the Bullwhip Avoidance Phase: The Synchronised Supply Chain

A bullwhip measurement system based on a two-criterion assessment—‘internal process efficiency’ and ‘customer service level’—is developed in this paper. The framework is designed to assess both individual (single member) and systemic (whole supply chain) performances. Data collection and calculation methods, update and monitoring mechanisms, as well as related procedures for each metric used, are detailed. A comparative analysis with a recent work by Barlas and Gunduz is performed, showing that the adoption of the proposed performance measurement system can help academics and practitioners to better understand, study and avoid the bullwhip effect. Such analysis also provides evidence on the relevance of considering when analysing the bullwhip effect in supply chains, the ‘customer importance’ aspect that is often forgotten in the published literature.