• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.1-12
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• 2016

The industry producing the parts of aircraft engines is a traditional order-made system with highly variety and small quantity, and the manufacturing system is the typical job shop with identical or non-identical multiple machines in a workstation. Furthermore, there are many alternative operations and alternative machines allowed in machining processes, and tremendous routings and assembly operations should be considered. Usually simulation is the most efficient technology to analyze such a complex system, and high modeling skills are required for developing the simulation models. In this paper, a case study on a company which produces the parts of aircraft engines is introduced, specially focused on simulation modeling methodologies for the complex system.

• IE interfaces
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• v.13 no.3
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• pp.512-520
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• 2000

An integrated process planning and scheduling model considering outsourcing in manufacturing supply chain is proposed in this paper. The process planning and scheduling considering outsourcing are actually interrelated and should be solved simultaneously. The proposed model considers the alternative process plans for job types, precedence constraints of job operations, due date of production, transportation time and production information for outsourcing. The integrated states include:(1) Operations sequencing, (2) Machine selection, (3) Scheduling with outsourcing under the due date. To solve the model, a heuristic approach based on genetic algorithm(GA) is developed. The proposed approach minimizes the makespan considering outsourcing and shows the best operation-sequences and schedule of all jobs.

• Korean Management Science Review
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• v.17 no.2
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• pp.125-134
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• 2000

Keeping the promised delivery date for a customer order is crucial for a company to promote customer satisfaction and generate further businesses. For this, a company should be able to quote the delivery date that can be achieved with the capacity available on the shop floor. In a dynamic make-to-order manufacturing environment, the problem of determining a delivery date for an incoming order with consideration of resource capacity, workload, and finished-product inventory can hardly be solved by an analytical solution procedure. This paper considers a situation in which a delivery date for a customer order is determined based on a job schedule, and presents the SimTriD algorithm that provides the best scheduling for determining a delivery date of customer order through the job schedule that efficiently utilizes manufacturing resources with consideration of interacting factors such as resource utilization, finished-product inventory, and due date.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.191-201
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• 1999

There have been a huge volume of researches concerning dispatching rules in job shop environments. Strangely, studies all but one pay no attention to multiple identical jobs due to the existence of production orders each of which calls for a fixed quantity, called an order size, of a specific part. Jobs arrive in the form of production orders in most, if not all, job shop type flexible manufacturing systems. This paper presents simple processing-time-based dispatching rules, and shows experimentally based on simulation that the rules with order-size considerations perform consistently well for tardiness and utilization measures. Several alternative strategies for rule specifications are examined.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.81-89
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• 1997

This study is concerned with the scheduling problems in flexible manufacturing systems(FMSs). The scheduling problem in FMSs is a complex one when the number of machines and jobs are increased. Thus, a heuristic method is recommended in order to gain near-optimal solutions in a practically acceptable time. The purpose of this study is to develope a machine and AGV dispatching algorithm. The proposed dispatching algorithm is a on-line scheduling algorithm considering the due date of parts and the status of the system in the scheduling process. In the new machine and AGV dispatching algorithm, a job priority is determined by LPT/LQS rules considering job tardiness. The proposed heuristic dispatching algorithm is evaluated by comparison with the existing dispatching rules such as LPT/LQS, SPT/LQS, EDD/LQS and MOD/LQS. The new dispatching algorithm is predominant to existing dispatching rules in 100 cases out of 100 for the mean tardiness and 89 cases out of 100 for the number of tardy jobs.

• Journal of the Korea Society of Computer and Information
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• v.4 no.3
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• pp.13-19
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• 1999

In this paper, we suggests a WIP (Work In Process) of FMC (Flexible Manufacturing Cell) analysis methods based on the TPN (Time Petri Nets) unfolding. Unfolding of PN is a partial order-based method for the verification of concurrent system without the state space explosion. The aim of this work is to formulate the general cyclic state scheduling problem to minimize the WIP to satisfy economical constraints. The method is based on unfolding of the original net into the equivalent acyclic description.

• Industrial Engineering and Management Systems
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• v.7 no.1
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• pp.99-107
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• 2008

This paper is concerned with scheduling in Flexible Manufacturing Systems (FMS) using a Fuzzy Logic (FL) approach. Four fuzzy input variables: machine allocated processing time, machine priority, machine available time and transportation priority are defined. The job priority is the output fuzzy variable, showing the priority status of a job to be selected for the next operation on a machine. The model will first select the machines and then assign operations based on a multi-criteria scheduling scheme. System/machine utilization, minimizing mean flow time and balancing machine usage will be covered. Experimental and comparative tests indicate the superiority of this fuzzy based scheduling model over the existing approaches.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.141-146
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• 2004

This research considers the problem of scheduling jobs on unrelated parallel machines with a common due date. The objective is to minimize the total absolute deviation of job completion times about the common due date. This problem is motivated by the fact that a certain phase of printed circuit board manufacturing and other production systems is bottleneck and the processing speeds of parallel machines in this phase are different for each job. A zero-one integer programming formulation is presented and two dominance properties are proved. By these dominance properties, it is shown that the problem is reduced to asymmetric assignment problem and is solvable in polynomial time.

• Journal of Digital Convergence
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• v.8 no.4
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• pp.83-95
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• 2010

This study is to investigate the relationship between job characteristics and job satisfaction in manufacturing company and difference of perceived job satisfaction from employment type(employees and temporary employees). The result of this study are as follows: (1) job characteristics such as skill variety, job identity, autonomy are related to job satisfaction, (2) the perceived job satisfaction is made a no difference between employees and temporary employees. The results above indicate that the job satisfaction difference from employment type can be used for organization to improve the organizational effectiveness including organizational competitiveness and employee's job satisfaction.

• IE interfaces
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• v.11 no.3
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• pp.65-75
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• 1998

This research considers the problem of scheduling jobs on parallel machines with non-common due dates and additional resource constraints. The objective is to minimize the total absolute deviation of job completion times about the due dates. Job processing times are assumed to be the same. This problem is motivated by restrictions that occur in the handling and processing of jobs in certain phases of semiconductor manufacturing and other production systems. We examine two problems. For the first of these, the number of different types of additional: resources and resource requirements per job are arbitrary. The problem is formulated as a zero-one integer linear programming and the Lagrangian relaxation approach is used. For the second case, there exists one single type of additional resource and the resource requirements per job are zero or one. We show how to formulate the problem as an assignment problem.