• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1999년도 춘계학술대회 논문집
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• pp.105-109
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• 1999

Tool shop of the D Heavy Industries Co.(DHI) fabricates engines for a bus, truck, small ship. In order to increase the production capacity of engines, DHI will be established the new tool shop that consists of a block line, head line, assembly line, test line and AS/RS in 1999. In order to assure the production capacity designed of the new tool shop for producing engines and improve the production process of it, it is needed to find a bottleneck process and an optimal way of allocating workloads among machines and workers to maximize the production. In a way to solve this, we model the engine fabrication process of the tool shop and analyze its performance by computer simulation. In this study, we at first identify the bottleneck processes of the engine fabrication process under the designed operation policy. Then, we derive some alternative operating policies applicable to the new tool shop of an engine, and analyze the optimal operation policy by comparing the performance of the tool shop following each alternative policy.

• 대한안전경영과학회지
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• 제25권3호
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• pp.45-53
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• 2023

In order to solve the rapidly increasing domestic delivery volume and various problems in the recent metropolitan area, domestic researchers are conducting research on the development of "Urban Logistics System Using Underground Space" using existing urban railway facilities in the city. Safety analysis and scenario analysis should be performed for the safe system design of the new concept logistics system, but the scenario analysis techniques performed in previous studies so far do not have standards and are defined differently depending on the domain, subject, or purpose. In addition, it is necessary to improve the difficulty of clearly defining the control structure and the omission of UCA in the existing STPA safety analysis. In this study, an improved scenario table is proposed for the AGV horizontal transport device, which is a key equipment of an urban logistics system using underground space, and a process model is proposed by linking systematic STPA safety analysis and scenario analysis, and UCA and Control Structure Guidelines are provided to create a safety analysis.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 하계학술발표대회
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• pp.176-176
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• 2005

• 정보학연구
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• 제6권4호
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• pp.125-134
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• 2003

본 논문은 통신 네트워크 운용 효율화를 위해 네트워크 운용요소별 상관관계를 분석하고 기본 모형을 구축하여 민감도 측정 방법을 제안하였다. 통신사업자는 연도별/부문별로 각각 그에 합당한 네트워크 운용기준을 설정하여 비용을 지출하여 왔으나 시장규모가 폭발적으로 성장하고 성장사업의 주력이 점차 변화하고 있는 상황에서, 적정수준에 대한 파악과 그를 위한 보다 포괄적이고 새로운 분석방법의 개발 및 적용이 요구된다. 전반적이고 포괄적인 관점에서 산출된 네트워크 운용의 적정비용에 대해 품질수준 개선을 위한 요소, 고객만족도 관련 요소 등과의 연계성을 중심으로 평가하고 개선하는 것이 본 논문의 가장 핵심적인 연구이다. 이러한 과정은 네트워크 운용의 가장 큰 부분을 차지하는 것이 품질관련 활동이고 품질관련 활동은 결국 고객만족도로 나타나게 되는 것이기 때문에, 각 요소별 개별적인 변화가 상호간에 미치는 영향을 중심으로 상관관계를 정립하여 민감도 측정을 바탕으로 네트워크 운용비용을 산출하는 것이 바람직한 분석이라 할 수 있다. 따라서, 본 논문에서는 네트워크 운용에 대한 체계적인 모형의 구축 및 효율성 측정을 위한 다양한 시나리오에 따른 민감도 측정을 위한 시스템을 개발하였다.

• 상하수도학회지
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• 제25권2호
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• pp.177-184
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• 2011

Membrane fouling is an unavoidable phenomenon in operation of seawater reverse osmosis (SWRO) and major obstacle for economic and efficient operation. When fouling occurs on the membrane surface, the permeate flux is decreased, on the contrary, the trans-membrane pressure (TMP) is increased, therefore operation and maintaining costs and potential damage of membranes are able to the pivotal risks of the process. Chemical cleaning process is essential to prevent interruptions for effective RO membrane filtration process. This study focused on proper chemical cleaning condition for polyamide RO membranes of 4 companies. Several chemical agents were applied for chemical cleaning under numbers of operating conditions. Additionally, a monitoring tool of FEEM as autopsy analysis method is adapted for the prediction of organic bio-fouling.

• Journal of Biosystems Engineering
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• 제35권3호
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• pp.206-213
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• 2010

The purpose of this study is to analyze musculoskeletal injuries in combine harvesting operation using a digital human model. In order to analyze problems in combine harvesting operation, the operations were broken into 5 work processes and then we preformed ergonomic and biomechanical analyses such as RULA test, Comfort Assessment and joint kinetic analysis for the each process. As a result, there was a clear need to change the combine operating environment, as the RULA score ranged from 4 to 7. In addition, we could find two major musculoskeletal injury factors which are the standing posture with upperbody forward tilting and inappropriate location of operating levers.

• 한국CDE학회논문집
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• 제6권4호
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• pp.222-228
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• 2001

In the milling operation, the burr can be generated on the intersection of cutting tool and workpiece. Due to burr formation, we expect lower efficiency in the operation and the cost increase. In order to understand the burr formation mechanism in the milling operation on the arbitrary feature, we developed an algorithm to analyse and predict the exit burr formation mechanism. Firstly, the recognition of arbitrary shaped workpiece was done through the CAD data. This data includes point information on the vertices of the workpiece. Secondly, tile CAM data regarding tool geometry, tool path, cutting speed, and material data are retrieved to simulate the actual cutting process. Thirdly, we predict the exit burr formation on the edge of workpiece based on the geometric analysis. Lastly, an algorithm implemented in the Windows environment to visualize the burr formation simulation. With this information, we can predict which portion of workpiece would have the exit burr in advance so that we call manage to find a way to minimize the edit burr formation in the actual cutting.

• 한국국방경영분석학회지
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• 제28권1호
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• pp.29-46
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• 2002

This study focuses primarily on the construction of the wartime sealift operation model from US to Korea. There are some uncertainties in the process of sealift operation such as the procurement rate of materiel in US, the distribution of KFS on four initial position locations at the start of the activation, and the number of ports and berths in the SPOES and SPODS. The sealift capability, based on the allocation of sealift assets such as the number of vessels, berths, and ports, is evaluated through simulation. The simulation is executed with a baseline wartime scenario and then the results are analyzed through a sensitivity analysis. The military planner may use of this model as a standard for establishing effective and concrete sealift operation plan in the near future.

• 한국정밀공학회지
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• 제17권5호
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• pp.108-115
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• 2000

This paper presents a variant type process planning system for machining of dies for auto-body production. Through the analysis of dies and their manufacturing processes, the authors categorized the press dies into 15 groups according to the similarity of machining features. After critically reviewing current manufacturing procedures, a standard process plan was defined for each group. The authors present MP3D the process planning system built on the standard process plan database, and show how they apply it at the die manufacturing plant of an automobile company. MP3D is expected to reduce major losses in machining such as reworking caused by mistakenly uncut features and eventually to help to accumulate the knowledge of operators. The operation sheet MP3D produces is also used in monitoring the progress of manufacturing of dies. This paper explains the whole development cycle of a process planning system from process analysis to application so that it can help readers to develop and apply a process planning system to their machine shops.

• 산업공학
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• 제17권spc호
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• pp.11-19
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• 2004

The purpose of this study is to identify the determinants of new venture performance according to years of operation in the view of integrated research framework. We propose the integrated new ventures performance model which is composed of entrepreneur, organization/resources, industrial environment, strategy/foundation process and availability of supporting systems as corresponding variables to new ventures performance. The determinants of new venture performance according to years of operation are identified through the multi-variate statistical analysis such as moderating regression analysis with the data gathered from 110 executives of venture companies. For internal variables, entrepreneur's managerial ability and technical expertise and employee's ability affect venture's performance increasingly as years of operation increases but resource procurement ability affects decreasingly. Related to external variables, years of operation plays positive moderating role on market size growth and supporting system availability, but negative role on government venture policy for venture performances. Though this study has limitation of small sample, limited questionnaire and performance measure, it has managerial contribution of identifying determinants of new venture performance according to years of operation.