• Management Science and Financial Engineering
• /
• v.2 no.1
• /
• pp.1-18
• /
• 1996

FMS operating system consists of several subsystems in general. i.e. tool grouping subsystem. tool/job assignment subsystem. job dispatching subsystem, and papers dealing with each subsystem were published by many researchers [1], [4], [6], [8], [9], [10], [11], [12], [13], [14], [15], [16]. This paper mainly discusses about tool/job assignment subsystem as a job loading procedure. that occupies the kernel position of overall FMS operating system. Its performance is evaluated through simulation experiments of an integrated operating system under a typical FMS hardware configuration implemented in many machining factories, which is composed of the proposed procedure as well as a job dispatching procedure including several heuristic dispatching rules in terms of rule-base.

• Journal of the military operations research society of Korea
• /
• v.22 no.2
• /
• pp.153-165
• /
• 1996

This paper presents an order releasing algorithm for an AMS. Order release policy determine order releasing time to shop floor so as to improve order management and shop performance. The proposed order releasing algorithm can cope with the dynamic environment of orders(e.g. change or cancel of order) flexibly and fastly, by processing individual order and exchanging the information(e.g. compeletion time or lateness of order, etc) with customer. And the objective of the order releasing algorithm is the observance of the due-date, therefore, it can provide customer with a reliability of order. Computer simulation is used to obtain the makespan of order which is the input data of the order releasing algorithm. The eight candidate part dispatching rules are simulated to selected an effective part dispatching rule for the computer simulation. By using the best effective part dispatching rule, the computer simulation is conducted to determine order releasing time.

• Journal of the Korea Safety Management & Science
• /
• v.13 no.4
• /
• pp.125-137
• /
• 2011

Customers are generally requiring a variety of products, earlier due date, and lower price. A manufacturing process needs the efficient scheduling to meet those customer's requirements. This study proposes the novel algorithm named MJA(Minimum Job completion time and AGV time) that increases the performance of machines and AGV(Automated Guided Vehicles) in many kinds of job types. MJA optimizes the bottleneck of machines and efficiency of AGV with considering two types of dispatching at the same time. Suggested algorithm was compared with existing heuristic methods by several simulations, it performed better for reducing the time of tardiness.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.06a
• /
• pp.385-386
• /
• 2022

Currently, global developed countries in shipping and logistics establish smart ports by introducing various digital technologies such as automated terminals and sharing platforms. This means that the importance of efficiency throughout the port by improving resource utilization efficiency and minimizing work idle time is increasing. Therefore, this study proposes a yard truck dispatching method of improving resource utilization efficiency. And we analyze the problems of the existing dispatching rules and develop Y/T dispatching algorithm that comprehensively considers related constraints. In addition, the simulation takes into account the terminal congestion based on the operation data of the Busan New Port, it is conducted using the existing dispatch method and developed Y/T dispatching algorithm. And the operational effects of analysis result are evaluated.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1998.10a
• /
• pp.216-219
• /
• 1998

This study proposes JPT(Job-Pair Tardiness) that choose operation to be expected to generate better schedule consequence in comparing schedulable operation sets in pair to minimize total tardiness evaluation function in performing scheduling. In result of comparison with existing assignment rules. JPT generates better solution than most other rules in all kinds of problems. So it is anticipated that this is used for initial solution of heuristic and is used for finding more improved solution.

• Journal of Korean Institute of Industrial Engineers
• /
• v.23 no.2
• /
• pp.343-357
• /
• 1997

This paper proposes a new AGV dispatching algorithm which is suitable for heterarchical manufacturing control structure. It is developed on the basis of bidding concept utilizing the information of work-in-process in incoming and outgoing buffers of workstation, and travel time of AGV. Since the bidding functions are functions of two parameters, sensitivity test is performed to find their appropriate values. The performance of the algorithm is compared with those of well-known existing rules in terms of system throughput through simulation on a hypothetical job shop type manufacturing system.

• Industrial Engineering and Management Systems
• /
• v.4 no.1
• /
• pp.23-35
• /
• 2005

This paper aims to develop a practical finite capacity MRP (FCMRP) system based on the needs of an automotive parts manufacturing company in Thailand. The approach includes a linear goal programming model to determine the optimal start time of each operation to minimize the sum of penalty points incurred by exceeding the goals of total earliness, total tardiness, and average flow-time considering the finite capacity of all work centers and precedence of operations. Important factors of the proposed FCMRP system are penalty weights and dispatching rules. Effects of these factors on the performance measures are statistically analyzed based on a real situation of an auto-part factory. Statistical results show that the dispatching rules and penalty weights have significant effects on the performance measures. The proposed FCMRP system offers a good tradeoff between conflicting performance measures and results in the best weighted average performance measures when compared to conventional forward and forward-backward finite capacity scheduling systems.

• Journal of Navigation and Port Research
• /
• v.41 no.3
• /
• pp.149-154
• /
• 2017

Recently, container terminal operators have made efforts to develop an efficient remarshalling plan in response to the increase in automation of equipment handling and transport of containers in the terminals. Usually, containers are handled by multiple AYCs(automated yard cranes) in-yard in an automated container terminal, and terminal operators establish a remarshalling plan using slack time to increase the efficiency of ship operation. This study develops the optimal mathematical model through mixed integer programming as a solution to the problem of dispatching multiple AYCs. Considering the difficulty of direct application to the field due to computation time, we analyze the five prototypical dispatching rules for real world adaptation. A numerical experiment found that the maximum weight ratio (MR) rule and the maximum weight (MW) rule are the ideal dispatching solutions to the multiple AYCs dispatching problem.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.42 no.1
• /
• pp.33-40
• /
• 2019

This study focuses on a job-shop scheduling problem with the objective of minimizing total tardiness for the job orders that have different due dates and different process flows. We suggest the dispatching rule based scheduling algorithm to generate fast and efficient schedule. First, we show the delay schedule can be optimal for total tardiness measure in some cases. Based on this observation, we expand search space for selecting the job operation to explore the delay schedules. That means, not only all job operations waiting for process but also job operations not arrived at the machine yet are considered to be scheduled when a machine is available and it is need decision for the next operation to be processed. Assuming each job operation is assigned to the available machine, the expected total tardiness is estimated, and the job operation with the minimum expected total tardiness is selected to be processed in the machine. If this job is being processed in the other machine, then machine should wait until the job arrives at the machine. Simulation experiments are carried out to test the suggested algorithm and compare with the results of other well-known dispatching rules such as EDD, ATC and COVERT, etc. Results show that the proposed algorithm, MET, works better in terms of total tardiness of orders than existing rules without increasing the number of tardy jobs.

• Proceedings of the KIEE Conference
• /
• 2001.11b
• /
• pp.167-169
• /
• 2001

This paper introduces the principal pool rules of the wholesale power market scheduled to be commissioned in January 2003 in Korea. The pool rules includes electricity trading procedures such as bidding, determining and publishing of forecasted market price, and 5 minute unconstrained dispatch scheduling for generation/market price, which are required for settlement after dispatching and should be conformed by KPX and participants in the market. Detailed procedures of the rules are under development and additional provisions for stable market operation are under discussion.