• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 추계학술대회논문집
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• pp.30-36
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• 1995

Conventionally design for multi-stage cold forging depends on the designer's experience and decision-making. Due to such non-deterministic nature of the process sequence design, a flexible inference engine is needed for process design expert system. In this study, A* searching algorithm was introduced to arrive at the vetter process sequence design considering the number of forming stages and levels of effective strain, effective stress, and forming load during the porcess. In order to optimize the process sequence in producing the final part, cost function was defined and minimized using the proposed A* searching algorithm. For verification of the designed forming sequences, forming experiments and finite element analyses were carried out in the present investigation. The developed expert system using A* searching algorithm can produce a flexible design system based on changes in the number of forming stages and weights.

• 한국정밀공학회지
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• 제16권8호
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• pp.59-70
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• 1999

This paper deals with automated computer-aided process planning by which designers can determine operation sequences even if they have little experience in the design of press working products. The computer-aided process planning in hot forging, deep drawing and blanking requires many kinds of technical and empirical skills based on investigation and collection of the knowledge of their processes. An approach to the CAPP system is based on the knowledge-based rules and the process knowledge base consisting of process planning rules is built. The methodology adopted to develop the system is elaborated in this paper. This system has been written in AutoLISP on the AutoCAD with a personal computer and provides powerful capabilities for process planning of hot forging, cold forging, deep drawing and blanking products.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 춘계학술대회 논문집
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• pp.82-85
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• 2002

A systematic investigation for process design in deep drawing is necessary for quality improvement of drawn cups. This study has been concentrated mainly on the influence of process design scheme on product qualities in cylindrical cup drawing. Three types of process design scheme were chosen in this study. That is, Case 1 is to finish drawing a cup of 50m in diameter in one stage, Case 2 and Case 3 are redrawing the drawn cups of 55, 65 mm in diameter to the final size respectively. Though experiments the maximum drawing force in two-stage cup drawing could be reduced up to 35% as compared with that of one-stage cup drawing. In addition, the Case 2 and Case 3 processes showed better product qualities than the Case 1 process when comparing distributions of thickness, hardness, dimensional accuracy.

• 한국주조공학회지
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• 제29권5호
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• pp.198-203
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• 2009

In order to manufacture copper ultra fine wire used for bonding wire in integrated circuit package, continuous casting process, which can produce high purity copper rod with small cross section, and wiredrawing process have to be optimized to prevent wire brakeage during entire manufacturing process of fine wire. The optimum condition for producing copper rod with mirror surface has to established by investigation of the effects of several parameters such as withdrawal speed, superheat and rod diameter on grain morphology of the cast rod and on its drawing characteristics to fine wire. The purpose of this study is to propose the optimized process parameters in continuous casting process in order to produce cast rod without internal defects, and to predict microstructure orientation suitable for wire drawing process.

• 소성∙가공
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• 제11권8호
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• pp.716-723
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• 2002

A systematic investigation for the process design in deep drawing is necessary to improve the quality of drawn cups. This study concentrates mainly on the influence of process desing scheme on the product qualities in cylindrical cup drawing. Three types of process design scheme were chosen in this study. Case 1 is to draw a finished cup of 50mm in diameter in one stage, Case 2 and Case 3 are redrawing the first drawn cups of 55, 65mm in diameter to the final size respectively. Through experiments the maximum drawing force in two-stage cup drawing can be reduced up to 24% as compared with that of one-stage cup drawing. In addition, Case 3 process results in better product qualities than the other two processes in terms of the distributions of thickness and hardness.

• 산업경영시스템학회지
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• 제21권45호
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• pp.237-246
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• 1998

In most statistical process control(SPC), control charts are used in which samples are taken and a suitable statistic is determined and plotted. In these control charts, control limits, ${\mu}{\pm}textsc{k{\sigma}}$, from which a decision is made are mostly ${\mu}{\pm}3{\sigma}$ and current literature in control charts are mainly concerned with detecting a shift in the mean. Therefore, when $\sigma$ is increased considerably after a long time, using control limits set at the first time causes a great deal of economic loss. In this paper the solutions to determine new control limits which maximizes the profit per unit produced and reduce $\sigma$ to economically optimal level for a certain cost when $\sigma$ is increased due to process deterioration are proposed. By applying new control limits, $\alpha$ error decreases considerably compared to apply initial control limits when $\sigma$ is increased due to process deterioration. Therefore, false alarm investigation cost drops down to the level of initial a error. And also this solution provides useful information regarding replacement of a process when the process is reviewed regularly.

• 한국안전학회지
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• 제31권2호
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• pp.119-126
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• 2016

Across the world, the industrialization has increased the frequency of climate anomaly. The size of damage due to recent natural disasters is growing large and fast, and the human damage and economic loss due to disasters are consistently increasing. Urbanization has a structure vulnerable to natural disasters. Therefore, in order to reduce damage from natural disasters, both hardware and software approaches should be utilized. Currently, however, the development of a statistical access process for 'analysis of disaster occurrence factor' and 'prediction of damage costs' for disaster prevention and overall disaster management is inadequate. In case of local governments, overall disaster management system is not established, or even if it is established, unscientific classification system and management lead to low utility of natural statistics of disaster year book. Therefore, in order to minimize disaster damage and for rational disaster management, the disaster damage survey process should be improved. This study selected gale as the focused analysis target among natural disasters recorded in disaster year book such as storm, torrential rain, gale, high seas, and heavy snow, and analyzed disaster survey process. Based on disaster year book, the gale damage size was analyzed and the issues occurring from the correlation of gale and damage amount were examined, so as to suggest an improvement plan for reliable natural disaster information collection and systematic natural disaster damage survey.

• 지질공학
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• 제18권1호
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• pp.69-81
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• 2008

산사태연구는 산사태를 발생시키는 여러 인자들의 상호관계를 규명하는 방법, 확률론적으로 산사태 발생가능성을 예측하는 방법 사태물질의 이동경로와 확산범위를 산정함으로써 산사태 위험성을 평가하는 방법 등으로 구분할 수 있다. 우리나라에서 발생된 대부분의 산사태는 여름철의 집중호우에 기인되는 것으로 기반암 상부의 토층에서 발생되며, 강우조건, 지형조건과 지질 및 토질특성 등에 영향을 받는 것으로 알려져 있다. 산사태 조사부터 위험성평가에 이르기까지의 산사태연구는 다양한 산사태를 체계적으로 조사하고 해석함으로써 공학적 관점에서 여러 특징들을 관찰하고 그 특성들을 총괄적으로 해석하여야만 한다. 이 연구에서는 경상남도 마천지역을 대상으로 산사태 현장조사를 수행하였다. 조사결과를 토대로 자연사면 산사태에 대한 최적의 표준모델로 활용할 수 있는 산사태 조사 및 해석 기법을 제안하고자 한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.204-210
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• 2011

This paper present investigation of interoperable process and interaction-facts between urban and new ATS signalling system for degrading, improvement or replacement in wireless communication-based train control system of urban driverless transit, and investigate interoperable requirement from joint program of cooperation-"wireless communication-based train control system's standard process construction and performance evaluation on urban transit" of first year result.

• Journal of Pharmaceutical Investigation
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• 제21권3호
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• pp.179-188
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• 1991

An HPLC assay method of a drug to be applied to the pharmacokinetic studies of the drug should be completely validated. The validation process for an HPLC assay method in a biological sample was discussed using the data obtained from the development of HPLC method for the simultaneous quantitation of verapamil and norverapamil in human serum. The validation criteria included were specificity, linearity, accuracy, precision, sensitivity, recovery, drug stability, and ruggedness of an assay method.