• Korean Journal of Computational Design and Engineering
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• v.19 no.4
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• pp.402-409
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• 2014

Presented in this paper is a scheduling method for semiconductor backend process considering the backward pegging. It is known that the pegging for frontend is a process of labeling WIP lots for target order which is specified by due date, quantity, and product specifications including customer information. As a result, it gives the release plan to meet the out target considering current WIP. However, the semiconductor backend process includes the multichip package and test operation for the product bin portion. Therefore, backward pegging method for frontend can't give the release plan for backend process in semiconductor. In this paper, we suggest backward pegging method considering the characteristics of multichip package and test operation in backend process. And we describe the backward pegging problem using the examples.

• Industrial Engineering and Management Systems
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• v.15 no.1
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• pp.11-18
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• 2016

This paper considers a scheduling problem in a flexible job shop with a reconfigurable manufacturing cell. The flexible job shop has both operation and routing flexibilities, which can be represented in the form of a multiple process plan, i.e. each part can be processed through alternative operations, each of which can be processed on alternative machines. The scheduling problem has three decision variables: (a) selecting operation/machine pairs for each part; (b) sequencing of parts to be fed into the reconfigurable manufacturing cell; and (c) sequencing of the parts assigned to each machine. Due to the reconfigurable manufacturing cell's ability of adjusting the capacity, functionality and flexibility to the desired levels, the priority scheduling approach is proposed in which the three decisions are made at the same time by combining operation/machine selection rules, input sequencing rules and part sequencing rules. To show the performances of various rule combinations, simulation experiments were done on various instances generated randomly using the experiences of the manufacturing experts, and the results are reported for the objectives of minimizing makespan, mean flow time and mean tardiness, respectively.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.2
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• pp.101-107
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• 2016

Generally, the shipbuilding industry has finite resources and limited workspace. Due to finite resources, limited workspace and state of block preparation, erection process in shipbuilding industry is frequently delayed than erection process scheduling which is planned at long-term plan stage. In this study, considering variability of block reserve ratio, the degree of delay in real erection process is measured and compared to scheduling which is planned at long-term plan stage in shipbuilding industry including finite capacity and variative lead time. Also, the erection process scheduling which has minimum lead time can be checked through simulation. The results of this study could be improved the accuracy of erection process scheduling by checking the main event compliance ratio by block reserve ratio and calculating the optimum erection pitch for the main event compliance.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.61-66
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• 2004

In this paper an effort is made to develop an innovative spatial arrangement concept pertaining to ship building industry. The spatial scheduling is the problem that concentrates on effective planning of available space and arrangements of blocks and in a priority manner. In order to create an effective spatial scheduling. a database providing the priority has to be available to make the erection sequence. Such a system works hand in hand with erection sequence generator program The erection sequence program works on the conventional network analysis method which uses a typical parent-children idea for the calculation of the ENT(possible earliest network start time) and LNT(possible latest network start time). This program works in a cyclic manner taking turns by calculating the ENT in upward trace and LNT on the return trace thereby generating the entire erection sequence diagram for the requisite problem The generated database serves as an input data for spatial scheduling problem. When the system works it takes into consideration the entire system based on heuristic concepts as mentioned. There system uses the spatial aspects such as the available area of the P. E area and plan area of the corresponding blocks and its priority of erection from the erection sequence generator program develops the spatial scheduling arrangement. In this paper using all these concepts an innovative spatial schedule development system developed.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.201-208
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• 2005

Recently, the container terminal requires the study of method to increase efficiency through change of its operation method. Loading plan is a very important part to increase the efficiency of container terminal. Loading Plan is largely divided into two cases, deciding loading location and loading scheduling and this Paper proposes a more efficient method of container loading scheduling. Container loading scheduling is a problem of combination optimization to consider several items of loading location and operation equipments. etc. An existing method of cluster composition that decides the order of container loading scheduling has a restriction to increase the efficiency of work owing to rehandling problem. Therefore, we Propose a more efficient method of container loading scheduling which composes containers with identical attribution, based on ship loading list and yard map, into stack units of cluster, applying to hierarchical clustering method, and defines the restriction of working order. In this process, we can see a possible working path among clusters by defining the restriction of working order and search efficiency will be increased because of restricted search for working path.

• Korean Journal of Construction Engineering and Management
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• v.5 no.2 s.18
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• pp.211-218
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• 2004

In a large owner organization, a program manager of multiple maintenance and remodeling projects has experienced increasing scale and complexity of coordinating the M/R projects with in-house technicians who belong to multiple trade shops. This paper proposes a dual-level hierarchical planning strategy that consists of a program master plan in the long-term horizon and a master construction schedule in an operational scheduling window. A rolling horizon approach to the program master plan is proposed to deal with the external uncertainty of unknown stream of project requests. A resource-constrained scheduling algorithm is developed to generate the master construction schedule in a scheduling window. During development of the algorithm, more emphasis is placed on long-term organizational resource continuity, especially flow management of program constraint resources, than ephemeral events of an individual activity and project. Monte Carlo simulation experiments of three scheduling windows are used to evaluate the relative performance of the proposed scheduling algorithm against three popular scheduling heuristics for resource-constrained multiple projects.

• Journal of Preventive Medicine and Public Health
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• v.19 no.1 s.19
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• pp.56-64
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• 1986

This paper describes a GPSS-based, multi-server queueing model that was developed to simulate the patient flow, and to analyze the effectiveness of the patient scheduling system under various conditions. Unpredictable and unacceptably long waits to receive the service at the outpatient department of a general hospital necessitated the study. Arrival and service time distribution needed for the simulation model were generated from actual arrival and service patterns observed during the peak hours. The simulation results show that a change in patient scheduling system (i.e. time interval between appointments, starting time. and the number of physicians) from a current system would significantly reduce the patient wait time. This study provides the hospital administrator with an analysis of patient scheduling system under several conditions, and will be used to plan future scheduling system and staffing. Studies such as this can demonstrate the value of simulation in providing information for use in future planning.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.248-249
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• 2021

Planning and Scheduling in Korean has been developed from Bar Chart to CPM, integrated management and EVM were attempted. As growing of overseas projects, Scheduler was also recognized as important one. However, the reality is that most Korean construction projects still remain in the preparation of construction plan and construction schedule in 1990s. The global Planning and Scheduling trend is EOT claims. I would like to understand the global trend of EOT claims and EOT analysis, and to find out Planning and Scheduling measures to successfully promote EOT claims.

• Journal of Korea Technology Innovation Society
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• v.2 no.3
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• pp.118-128
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• 1999

This study attempts to provide an efficient method for managing the Nuclear R&D projects. It should be noted that the technology and experiences to develop a well-balanced plan and mon-itoring for the R&D project are not yet well established when compared with the commercial con-structionand engineering projects. This study recommends that the R&D project manager utilize the scheduling techniques to establish an integral management system taking in to account the un-certainties in the research environment. Based upon the results of a case study for the Liquid Metal Reactor Design Technology Development Project which is led by the KAERI this study also con-firms that it is possible to run the national nuclear R&D projects with the Scheduling & Planning.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.2
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• pp.323-341
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• 1997

Traditionally, the Process Planning problems and the Scheduling problems have been considered as independent ones. However, we can take much advantages by solving the two problems simultaneously. In this paper, we deal with the enlarged problem that takes into account both the process planning and the scheduling problems. And we present a solution algorithm for the problem assuming that the given process plan data is represented by AND/OR graph. A mathematical model(mixed ILP model) whose objective is the minimization of the makespan, is formulated. We found that we can get the optimal solutions of the small-size problems within reasonable time limits, but not the large-size problems. So we devised an algorithm based on the decomposition strategy to solve the large-scale problems (realistic problems) within practical time limits.