• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.91-98
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• 2002

In the study, we propose, for the practical approaches of job shop scheduling, the new dispatching rules of Job shop scheduling in order to complement the practical applications in the existing researches. The performance of the new dispatching rules is compared and analyzed with the existing methods through the computer experiments in the assumed conditions. The results can be useful to improving a field application of the job shop scheduling.

• Journal of the Korea Society for Simulation
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• v.7 no.1
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• pp.39-51
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• 1998

In this paper, MVED (Minimum Vehicle's Empty Distance), a new dispatching rule for a Single Loop-Single Vehicle AGV system, is developed. Single Loop-Single Vehicle AGV system consists of segmented bi-directional single loops, in which only one AGV is assigned. The MVED rule is focused on minimizing vehicles empty travel distance. Using simulation, the performance of the MVED is compared with that of existing dispatching rules such as STT/D and MEVTT. The results show MVED rule's better performance than others. ARENA is used as a simulation language.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.78-86
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• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• Korean Journal of Computational Design and Engineering
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• v.19 no.3
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• pp.236-244
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• 2014

Presented in the paper is a reservation based dispatching rule to achieve the on-time delivery in system LSI (large scale integrated circuit) semiconductor fabrication (FAB) with urgent orders. Using the proposed reservation based dispatching rule, urgent lots can be processed without waiting in a queue. It is possible to achieve the on-time delivery of urgent orders by reserving a proper tool for the next step in advance while urgent lots are being processed at the previous step. It can cause, however, tardiness of normal lots, because the proposed rule assign urgent lots first. To solve this problem, the proposed rule tries to find the best tool for the reservation in the tool group, which can minimize idle time, and the reservation rule is applied at all tools except for photolithography tools (bottleneck). $MOZART^{(R)}$ which is developed by VMS solutions are used for simulation experiments. The experimentation results show that the reservation based dispatching rule can achieve the on-time delivery of normal lots as well as urgent lots.

• Journal of Fisheries and Marine Sciences Education
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• v.6 no.2
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• pp.130-142
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• 1994

To investigate the effective scheme to secure the specialized instructors in the governmental officials training facilities, the authors made a survey on the opinion concerning the dispatching service system of officials as instructors to the Fisheries Officials Training Institute on the fisheries specialized officials in the Fisheries Agency and its affiliated organization. The obtained results can be summarized as follows : 1. The exiting personnel management system has a lot of difficulties to secure the specialized instructors. Even though the difficulties may be solved by inviting part-time instructors to some extent, it is remote from the goal. The active utilization of dispatching service system of specialized officials to the Institute as instructors during the limited term will be effective rather than re-arrangement of personnel system or amendment of laws and ordinances to secure the specialized instructors. 2. The response of specialized officials who are objected in the present survey on the dispatching service system to the Institute appeared to be affirmative considerably, and then the dispatching service system may be expected of high efficiency in its realization.

• Journal of Korean Institute of Industrial Engineers
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• v.34 no.3
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• pp.296-307
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• 2008

A semiconductor production system has sophisticated manufacturing operations and needs high capital investment for its expensive equipment, which warrants efficient real-time flow control for wafers. In the bay, we consider material handling equipment that can handle multiple carriers of wafers. The dispatching logic first determines the transportation time of each carrier to its destination by each unit of transportation equipment and uses this information to determine the destination machine and target carrier. When there is no available buffer space at the machine tool, the logic allows carriers to stay at the buffer of a machine tool and determine the delay time, which is used to determine the destination of carriers in URL. A simulation study shows this dispatching logic performs better than the procedure currently in use to reduce the mean flow time and average WIP of wafers and increase efficiency of material handling equipment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.54
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• pp.77-85
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• 2000

One form of job shop scheduling problem in contemporary automated manufacturing such as flexible manufacturing systems (FMS's) is presented which we call the FMS dispatching priority problem. The FMS dispatching priority problem seeks the best dispatching priority of parts and operations, and is essentially a combinatorial optimization problem. Because of the complicated mechanism of the system, the performance of a given dispatching priority must be evaluated via simulation. Simulated annealing have been applied to the problem, and it is found that appropriate parameter setting will be desirable to get good, if not the optimal, solutions within a limited amount of time under the presence of heavy computational burden due to simulation. More specifically, experiments reveal that initial temperature is the single most important factor among other parameters and factors, and that the appropriate initial temperature depends on the allowable computer time in such a way that the less time one can afford to spend, the lower the appropriate initial temperature should be.

• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.181-192
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• 2010

We develop a dispatching policy for stochastic scheduling simulation especially for a continuous manufacturing system with machine breakdowns. The proposed dispatching policy computes an urgency index with the consideration of re-heating, setup cost and remaining due date. Prioritized by the index, we execute swapping or reassigning material sequences so as to minimize the total penalty cost. To evaluate the performance of the proposed policy, a discrete event simulation is developed. With 200 data sets and 20 iterations, we compare the performance of the urgency policy with those of SPT (Shortest Processing Time) and FCFS (First Come First Serve) which are the most common policies. The result shows that the proposed policy consistently gives the lowest total costs by reducing the penalty costs for lateness.

• The Korean Journal of Emergency Medical Services
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• v.3 no.1
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• pp.33-42
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• 1999

The purposes of this study which was conducted by studying the literature on Emergency Medical Dispatch System are to provide some developmental policies of quality management, pre-arrival instructions, priority dispatch protocols, training program for the dispatchers(Emergency Medical Dispatchers or EMDs) in Korea and to promote understanding emergency medical dispatching. The conclusions from this summarized as follows; (1) It is confirmed that there has been little study on the Emergency Medical Dispatch System in Korea, because for the first time, the real Emergency Medical Services were introduced into Korea in 1994, and the importance of the Emergency Medical Dispatch System has not been realized. (2) Only some squads are using a set of dispatch protocols, others aren't. (3) In spite of trying to introduce a new set of dispatch protocols, it isn't the priority dispatch system using a complete set of dispatch protocols which has key questions, pre-arrival instructions, mode & configuration based on patient assessment. (4) The EMS is unable to promote the service capacity by using quality management, because there is no medical control on the emergency medical dispatching and the EMDs. (5) There are no medical directors in the communications center who are in charge of the medical control to detect problems derived from the EMS and to solve them. (6) There are no systematic training program for the EMDs who are taking charge of dispatching. (7) Having a deep relation to the elements of the EMS, the emergency medical dispatching is subject to restriction of those elements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3232-3238
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• 2010

As flexible manufacturing systems (FMSs) are highly automated and required flexibility to satisfy market need, dispatching rules are constrained by specific environments of manufacturing systems such as mechanical failures, absence of employees, and lack of spare parts. In this paper, an ontology-based knowledge approach is proposed to improve efficiency of system through adapting suitable dispatching rules, considering context in a FMS shop floor, which consists multiple manufacturing cells. the multi-agents monitor manufacturing system status and job so that it figures out a dispatching rule considering context. To demonstrate the proposed approach, a proof-of-concept prototype system has been implemented in the $JADE^{TM}$ platform and Protege to make OWL DL ontology.