Job shop scheduling Research Papers (original) (raw)

Metalworking companies represent one of the strategic sectors in the regional economy of the Caldas department in Colombia; in fact, this sector is involved in 31% of the department’s industrial establishments and 29% of industrial... more

Metalworking companies represent one of the strategic sectors in the regional economy of the Caldas department in Colombia;
in fact, this sector is involved in 31% of the department’s industrial establishments and 29% of industrial employment according to DANE (Colombian State Statistical Department) statistical data from 2005. The sector also exports to Andean countries. However, preliminary studies conducted with 57% of the entrepreneurs from this sector (excluding micro companies and family businesses) have revealed serious structural (technology, processing, installations) and infrastructure weaknesses (production planning, quality systems) in these organisations’ production systems. It is hoped that this paper will lead to disseminating the results amongst the academic community of implementing a comprehensive methodology for improving the production system of a pilot company from this particular sector. An experimental framework for improving the levels reached by the system regarding such priorities is proposed following universally accepted methodology in discrete simulation studies; it proposes using sequential bifurcation, factorial design and response surface experimentation based on defining and weighting the competing priorities which the company should achieve. The improvements in the pilot company’s production system priorities are presented in terms of an effectiveness index (EI) which rose from 1.84 to 2.46 by the end of the study.

The choice of an appropriate social rate of discount is critical in the decision-making process on public investments. In this paper we review the literature on social discounting, and address in particular a recently growing field of... more

The choice of an appropriate social rate of discount is critical in the decision-making process on public investments. In this paper we review the literature on social discounting, and address in particular a recently growing field of related research, that is, individual time preferences. We argue that an explicit consideration and analysis of the behaviour of individuals regarding the concept and the use of an appropriate social discount rate are essential for balanced decision making in the public sector, especially, though not exclusively, in the field of resource or environmental policy.

: This thesis considers the combining of a ship overhaul project network with a shipyard project network to minimize possible scheduling conflicts during the ship overhaul process. The combined project is called the ship overhaul project... more

: This thesis considers the combining of a ship overhaul project network with a shipyard project network to minimize possible scheduling conflicts during the ship overhaul process. The combined project is called the ship overhaul project network. A heuristic multi-pass scheduling algorithm is developed to combine the ship's and shipyard's project networks. The algorithm is tested with two sets of data. The work spaces on shipboard are considered as a common resource to both project networks, and the ship's complement is an uncommon but limited resource. Since the real-world problem is larger than the context of this thesis, some simplifying assumptions were made. The most important of these are the reliable communication link between ship and shipyard prior to and/or during the overhaul process, and sufficient knowledge about the shipyard project network as early as possible after overhaul initiation. (Author)

In this paper, we address parallel machine scheduling problems with an objective of minimizing the maximum weighted absolute lateness. Memetic algorithms are applied to solve this problem. The proposed method is compared with genetic... more

In this paper, we address parallel machine scheduling problems with an objective of minimizing the maximum weighted absolute lateness. Memetic algorithms are applied to solve this problem. The proposed method is compared with genetic algorithms and heuristics on randomly generated test problems. The results show that the memetic algorithm outperforms the others

The scheduling of manufacturing processes aims to find sequences of jobs on given machines optimal by a selected criterion, e.g. minimal completion time of all operations. With respect to NP-hardness of these problems and the necessity to... more

The scheduling of manufacturing processes aims to find sequences of jobs on given machines optimal by a selected criterion, e.g. minimal completion time of all operations. With respect to NP-hardness of these problems and the necessity to solve them by heuristic methods, the problem representation and the effectiveness of their procedures is substantial for computations to be completed in a reasonable amount of time. In this paper, we deal with job shop scheduling problem (JSSP) in a disjunctive graph-based representation. Turning all undirected edges into directed ones, the problem is transformed to a problem solvable by the Critical Path Method (CPM). We propose an original implementation of the CPM that makes it possible to decrease its time complexity and thus also the running time of all JSSP iterations.

This paper presents a two-stage genetic algorithm (2S-GA) for multi-objective Job Shop scheduling problems. The 2S-GA is proposed with three criteria: Minimize makespan, Minimize total weighted earliness, and Minimize total weighted... more

This paper presents a two-stage genetic algorithm (2S-GA) for multi-objective Job Shop scheduling problems. The 2S-GA is proposed with three criteria: Minimize makespan, Minimize total weighted earliness, and Minimize total weighted tardiness. The proposed algorithm is composed of two Stages: Stage 1 applies parallel GA to find the best solution of each individual objective function with migration among populations. In Stage 2 the populations are combined. The evolution process of Stage 2 is based on Steady-State GA using the weighted aggregating objective function. The algorithm developed can be used with one or two objectives without modification. The genetic algorithm is designed and implemented with the GALIB object library. The random keys representation is applied to the problem. The schedules are constructed using a permutation with m-repetitions of job numbers. Performance of the proposed algorithm is tested on published benchmark instances and compared with results from other published approaches for both the single objective and multi-objective cases. The experimental results show that 2S-GA is effective and efficient to solve job shop scheduling problem in term of solution quality.

The Job-shop scheduling is one of the most important industrial activities, especially in manufacturing planning. The problem complexity has increased along with the increase in the complexity of operations and product-mix. To solve this... more

The Job-shop scheduling is one of the most important industrial activities, especially in manufacturing planning. The problem complexity has increased along with the increase in the complexity of operations and product-mix. To solve this problem, numerous approaches have been developed incorporating discrete event simulation methodology. The scope and the purpose of this paper is to present a survey which covers

Abstract. Variable Neighbourhood Search (VNS) is one of the most recent metaheuristics used for solving combinatorial optimization problems in which a systematic change of neighbourhood within a local search is carried out. In this paper,... more

Abstract. Variable Neighbourhood Search (VNS) is one of the most recent metaheuristics used for solving combinatorial optimization problems in which a systematic change of neighbourhood within a local search is carried out. In this paper, a variable neighbourhood search ...

Businesses around the world experience many challenges to acquire raw materials, parts, subassemblies, and the other necessary inputs to their production systems. As businesses are all moving into the e-commerce platform to gain market... more

Businesses around the world experience many challenges to acquire raw materials, parts, subassemblies, and the other necessary inputs to their production systems. As businesses are all moving into the e-commerce platform to gain market shares, they realize that electronic supply chain management (e-SCM) powered by enterprise resource planning systems (ERPs) are the new norms and no business organization can operate without both in the new world of e-commerce. Little attention has been devoted to e-SCM dynamic with ERP and the challenges they pose to organizations. In the e-commerce environment, e-SCM is among the most important factors to organizational success. Effective e-SCM can enhance competitiveness and increase market share leading a higher profitability. Nevertheless, the new e-SCM professionals and other actors must understand the factors that undergird e-SCM performance, their drivers, and the necessity of fully functional ERPs for an effective e-SCM.

This paper provides a simulation model to study the effect of the work-in-process control on due date performance in job shop environment. The due date performance is measured by both the number of tardy jobs and the total tardiness. The... more

This paper provides a simulation model to study the effect of the work-in-process control on due date performance in job shop environment. The due date performance is measured by both the number of tardy jobs and the total tardiness. The simulation runs include different shop configurations (flow shop and general job shop), workloads and sequencing rules. As expected, the results reveal that due date performance is highly dependent on the work-in-process, particularly after the system reaches saturation. Nevertheless, the model is very useful to show job shop managers the effect of the work-in-process control in the due date meeting performance.

This paper presents a tabu search approach for the job-shop scheduling problem. Although the problem is NP-hard, satisfactory solutions have been obtained recently by tabu search. However, tabu search has a problem-specific and parametric... more

This paper presents a tabu search approach for the job-shop scheduling problem. Although the problem is NP-hard, satisfactory solutions have been obtained recently by tabu search. However, tabu search has a problem-specific and parametric structure. Therefore, in the paper, we focussed on the tabu search strategies and parameters such as initial solution, neighborhood structure, tabu list, aspiration criterion, elite solutions list, intensification, diversification and the number of iteration. In order to compare some neighborhood strategies and tabu list length methods, a computational study is done on the benchmark problems.

From its roots in job-shop scheduling, research into fixed priority pre-emptive scheduling theory has progressed from the artificial constraints and simplistic assumptions used in early work to a sufficient level of maturity that it is... more

From its roots in job-shop scheduling, research into fixed priority pre-emptive scheduling theory has progressed from the artificial constraints and simplistic assumptions used in early work to a sufficient level of maturity that it is being increasingly used in the implementation of real-time systems. It is therefore appropriate that within this special issue we provide an historical perspective on the development of fixed priority pre-emptive scheduling.