• 한국경영과학회지
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• 제20권1호
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• pp.27-34
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• 1995

In this paper, we have developed a model to determine the input quantity to be processed at each stage of a multi-stage production system in which the yield at each stage may be random and may need reworking at this stage. Yield randomness. especially in a semiconductor industry, is a most challenging problem for production control. The demand for flnal product is uncertain. We have extended the model proposed in Park and Kim[9] to consider a multiple number of reworkings which can be done at any stage prior to or tat the stage whose output in bad, depending on the level of the defect.

• 자원환경지질
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• 제20권1호
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• pp.1-18
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• 1987

The Cheolam silver deposits are emplaced along the fractures in breccia dike and the Hongjesa granite. Breccia dike contains fragments of late Cretaceous acidic volcanic rocks and other fragments of various rocks distributed in the mine area. Therefore it is presumed that the mineralization was taken place in later than late Cretaceous time. Mineral paragenesis is complicated by multiple episodes of fracturing. Six distinct depositional stages can be recognized: stage I, deposition of base metal sulfides; stage II, deposition of base metal sulfides and silver minerals; stage III, deposition of carbonates; stage IV, deposition of silver minerals and base metal sulfides; stage V, deposition of silver minerals; stage VI, deposition of barren quartz. Silver minerals from the deposits are native silver, acanthite, pyrargyrite, argentian tetrahedrite, stephanite, polybasite, pearceite, allargentum, antimonial silver and electrum. Fluid inclusion studies ware carried out for stage I, II, IV and VI quartz and stage III calcite. Homogenization temperatures for each stage are as follows: stage I, from $225^{\circ}$ to $360^{\circ}C$; stage II, from $145^{\circ}$ to $220^{\circ}C$; stage III, from $175^{\circ}$ to $240^{\circ}C$; stage IV, from $130^{\circ}$ to $185^{\circ}C$; stage VI, from $120^{\circ}$ to $145^{\circ}C$. Salinities of ore fluids were in the range of 4 and 10 wt.% equivalent NaCl over stage I and stage VI. Ore mineralogical data of each stage indicate that temperatures are within the range of homogenization temperature of fluid inclusions and sulfur fugacities declined steadily from $10^{-9.7}atm$. to $10^{-18.7}atm$. through stage I into stage V.

• 한국항해항만학회지
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• 제33권4호
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• pp.271-275
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• 2009

A strategic decision making on location selection for product transportation includes many tangible and untangible factors. To choose the best locations is a difficult job in the sense that objectives usually conflict with each other. In this paper, we consider a multi stage multi criteria transshipment problem with different types of items to be transported from the sources to the destination points. For the optimization of the problem, a goal programming formulation will be presented in which the location selection for each product type will be determined under the multi objective criteria. In the study, we generalize the transshipment model with a variety of product types and finite number of different intermediate nodes between origins and destinations. For the selection of the criteria we selected the costs(fixed cost and transportation cost), location numbers, and unsatisfied demand for each type of products in multi stage transportation, which are the main goals in transshipment modelling problems. The related conditions are also modelled through linear formats.

• 대한산업공학회지
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• 제33권2호
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• pp.213-220
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• 2007

This paper considers a two-stage hybrid flow shop scheduling problem for the objective of minimizing the number of tardy jobs. Each job is processed through the two production stages in stages, each of which has multiple identical parallel machines. The problem is to determine the allocation and sequence of jobs at each stage. A branch and bound algorithm that gives the optimal solutions is suggested that incorporates the methods to obtain the lower and upper bounds. Dominance properties are also suggested to reduce the search space. To show the performance of the algorithm, computational experiments are done on randomly generated problems, and the results are reported.

• 한국경영과학회지
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• 제31권1호
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• pp.1-13
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• 2006

In this paper we consider a design problem of a cyclic queueing network with two stages, each with a local buffer of limited capacity. Based on the theory of reversibility and product-form solution, we derive the throughput function of the network as a key performance measure to maximize. Two cases are considered. In case each stage consists of a single server, an optimal allocation policy of a given buffer capacity and work load between stages as well as the optimal number of customers is identified by exploiting the properties of the throughput function. In case each stage consists of multiple servers, the optimal policy developed for the single server case doesn't hold any more and an algorithm is developed to allocate with a small number of computations a given number of servers, buffer capacity as well as total work load and the total number of customers. The differences of the optimal policies between two cases and the implications of the results are also discussed. The results can be applied to support the design of certain manufacturing and computer/communication systems.

• 대한물리치료과학회지
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• 제1권2호
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• pp.355-365
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• 1994

Ilizarov limb lengthening has been the new method to deal with a variety of orthopaedic problems. Ilizarov apparatus consists of stainless steel rings that surround the limb and are interconnected by threaded rods. Tensioned wires pierce the bone in the plane of each ring and are tightly attached to the ring. Ilizarov has reported distraction osteogenesis with the use of the typical fixator that allows functional loading. The purpose of this commentary is to introduce a four-stage rehabilitation protocol currently used by the authors in the physical therapy management of a post -limb lengthening. Each treament stage corresponds to a medical stage in the lengthening process. Treatment goals for each of the physical therapy treatment stage are presented to guide treatment planning. Two case examples are presented to illustrate the use of the management goals in treatment planning.

• 한국실내디자인학회논문집
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• 제19권3호
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• pp.180-187
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• 2010

The purpose of this study was to examine the application tendency of the western classical style which appears in contemporary performing arts centers. The types of space in performing arts centers were investigated according to the times. There were somewhat fixed stage and auditorium types for each period ; the ancient times had the arena stage and round auditorium, the Renaissance the proscenium stage and the U-shaped auditorium, the Elizabethan period the thrust stage and polygonal auditorium, and the modern times the proscenium and apron stage, the horseshoe and fan type auditorium. Today since the purposes of performance are multiple, a variety of stage types are applied to each performing arts center. They use various spaces and performances of multiple purposes by moving and transforming the stage and auditorium according to the kinds of performance as a variation of the arena and proscenium stage. Recently there appear complex performing arts centers that can plan performing spaces of diverse sizes and forms to fit the functions of a performance in a large building. Since they put on performances in a large space according to the characteristics of the kind of performance, the intentions and goals of the performance are well delivered to the audience.

• 한국경영과학회지
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• 제26권4호
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• pp.1-21
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• 2001

The purpose of this stuffy is to derive critical success factors for ERP system implementation by integrating managerial, technical. human resource and organizational culture factors welch have been proposed as influencing factors for the performance of ERP system implementation in previous studios. Especially, this stuffy divides ERP system implementation process into preparation stave, implement stage and settle-down and stabilization stave, and then derives critical success factors in each stage. The data for empirical analysis of the research model are collected from 64 companies and the respondents for questionnaire consist of ERP system implementation project managers and user department managers in companies which have already operated it after ERP system installation. The main results of this study are as follows. First, it derives 27 success factors through comprehensive review of various factors which may affect ERP system implementation performance, and categorizes them into one of three stapes preparation stave, implement stage, and settle-down and stabilization stage. Second, the relationship between many success factors at each stave (preparation stave, implement stage, and settle-down and stabilization stave) and performance variables is tested. As a result, the significant correlations between many success factors at each stage and ERP system implementation performance are found, and the difference among success factors in the degree of influencing the system performance is significantly shown. finally, the relationship between process-oriented performance variables and result-oriented performance ones is tested. As a result, it is found that there is significant correlation between process-oriented performance variables except for one variable-project resource management appropriateness - and result-oriented performance ones. The theoretical contribution of this study is to derive a comprehensive model of critical success factors for implementing ERP system project from the system deve1opment life cycle perspective, and empirically test it through field survey with a wide range of data collection. And, the practical implication of this study is to present the desirable guidelines for performing ERP system implementation project successfully.

• 대한족부족관절학회지
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• 제26권2호
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• pp.71-77
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• 2022

Purpose: This study sought to investigate the appropriate indications for intra-articular injection of hyaluronic acid in ankle osteoarthritis, its efficacy at each stage of osteoarthritis and to compare the efficacy related differences at each stage. Materials and Methods: A retrospective study was conducted from January 2016 to September 2019 on 43 patients (50 cases) diagnosed with ankle arthritis and given intra-articular injection of hyaluronic acid. Patients were classified according to the modified Takakura ankle osteoarthritis stages. Stage 2 comprised 24 cases; stage 3A, 15 cases; stage 3B, 8 cases; and stage 4, 3 cases. The clinical evaluation was carried out using the visual analogue scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) score, and the Foot and Ankle Outcome Score (FAOS). The patients' satisfaction with the injection was evaluated at 1 year after injection. A radiographic evaluation was performed to gauge the progression of osteoarthritis before and after the injection. Results: The VAS, AOFAS score, and FAOS at 3 months and 1 year after injection showed statistically significant improvements compared to those before the injection. There was a significant difference in the VAS for each stage over time; however, this was not the case with the AOFAS score and the FAOS. A significant improvement of the VAS after injection was seen only in stage 3A when compared with the other stages. The overall satisfaction rate with the injection was 90%. There were no ankle osteoarthritic stage changes in the serial follow-up radiograph. Conclusion: Intra-articular injection of hyaluronic acid resulted in a significant clinical improvement up to 1 year after the injection. Therefore, the intra-articular injection of hyaluronic acid could be a treatment option for ankle osteoarthritis.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1996년도 추계학술대회발표논문집; 고려대학교, 서울; 26 Oct. 1996
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• pp.307-309
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• 1996

This paper analyses a deterministic scheduling problem concerned with manufacturing two types of components at a pre-assembly stage which consists of two independent feeding machines each producing its own type of component. Each type represents a unique component which may have variations in its size or quality. Therefore, the completion time of each component depends on both its type and quality (size) variations. Such manufactured components are subsequently assembled into various component dependent products. The problem has the objective measure of minimizing the total weighted completion time of a finite number of jobs(products) where the completion time of each job is measured by the latest completion time of its two components at the pre-assembly stage. The problem is shown to be NP-complete in the strong sense. A WSPT rule coupled with a machine-aggregation idea is developed for good heuristics which show the error bound of 2.