• 한국CDE학회논문집
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• 제16권6호
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• pp.397-406
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• 2011

Since tolerance allocation in a mobile phone camera manufacturing process greatly affects production cost and reliability of optical performance, a systematic design methodology for allocating optimal tolerances is required. In this study, we proposed the tolerance optimization procedure for determining tolerances that minimize production cost while satisfying the reliability constraints on important optical performance indices. We employed Latin hypercube sampling for evaluating the reliabilities of optical performance and a function-based sequential approximate optimization technique that can reduce computational burden and well handle numerical noise in the tolerance optimization process. Using the suggested tolerance optimization approach, the optimal production cost was decreased by 30.3 % compared to the initial cost while satisfying the two constraints on the reliabilities of optical performance.

• 동력기계공학회지
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• 제3권4호
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• pp.63-68
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• 1999

The determination of the optimal machining parameters in metal cutting, such as cutting speed, feed rate, and depth of cut, is an important aspect in an economic manufacturing process. The main objective in general is either to minimize the production cost or to maximize the production rate. Also there are constraints on all the machining operations which put restrictions on the choice of the machining parameters. In this paper as an objective function the production cost is considered with two constraints, surface finish and cutting power. Genetic Algorithm is applied to determine the optimum machining parameters, and the effectiveness of the applied algorithm is demonstrated by means of an example, turning operation.

• Industrial Engineering and Management Systems
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• 제10권1호
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• pp.1-6
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• 2011

This paper describes the issue of batch scheduling.In food production, the lead-time from produc-tion to sale should be decreased becausefreshness of the product is important. Products are shipped at diverse times depending on a demand of sellers, because the types of sellers has become diversified such as super-markets, convenience stores and etc. production of quantity demanded must be completed by time to ship it then. The authors consider a problem with due-dates constraints and construct the algorithm to find the opti-mal schedule that satisfy the due-dates constraint, batch size constraint, inventory time constraint and mini-mize total flow time.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2011년도 춘계학술대회
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• pp.541-552
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• 2011

Many of Korea major companies have appled as strategy of management innovation Six Sigma, Lean and Theory of Constraints. Six Sigma has mainly focused to reduce variation. Lean has mainly focused to reduce wastes and Theory of Constraints has mainly focused that bottleneck of constrains production and sales. This bottleneck is caused by constraint resources and it should be the main role of manager to explore constraint resource. Although their mainly focus are different, they are used to improve productivity and quality. In this paper, as strategy of management innovation, study on analysis and comparison plan of Six Sigma, Lean and Theory of Constraints. From the literature survey and application cases, it is suggested and discussed that how to plan of application as strategy of management innovation successfully. The suggested plan of application could be a good guideline that it could be a apply of companies.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2000년도 춘계학술대회 논문집
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• pp.57-66
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• 2000

Production-distribution planning is the most important part in supply chain management (SCM). To solve this planning problem, either analytic or simulation approach has been developed. However these two approaches have their own demerits in problem solving. In this paper, we propose a hybrid approach which is a specific problem solving procedure combining analytic and simulation method to solve production-distribution problems in supply chain. The machine capacity and distribution capacity constraints in the analytic model are considered as stochastic factors and adjusted by the proposed specific process according to the results from independently developed simulation model which includes general production-distribution characteristics.

• 대한조선학회논문집
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• 제31권3호
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• pp.154-164
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• 1994

본 연구에서는 경제적이고, 품질이 우수한 용접 조립보의 생산을 위해 요구되는 조건을 컴퓨터 시뮬레이션 방법 및 최적화 방법을 이용해서 찾고자 한다. 이를 위해 용접 조건과 가열 조건 등 조립보의 생산 과정을 지배하는 변수를 선정하고, 이 변수에 따라 조립보 생산비를 추정할 수 있는 모델을 제시하여, 생산에 따른 제한 조건을 만족시키면서, 생산비가 최소가 되는 생산 변수를 구하였다. 더 나아가서 설계 및 생산의 통합 제어를 위해 용접 조립보의 생산에 따른 총 비용을 산출할 수 있는 추정식을 제시하고, 선급 규정에 따라 설계하는 과정까지 포함하여 최적화를 수행하였다. 또한 곡직가열이 불가능한 경우를 가정하여, 가중치법에 기초한 다목적 최적화 기법을 도입하고 최소 비용과 최소 변형의 절충해를 얻는 방법을 제시하였다.

• 한국산학기술학회논문지
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• 제10권10호
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• pp.2935-2944
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• 2009

중소 PCB 제조업체에서는 외부 생산 환경 변화, 복수개의 제약공정, 많은 공정수, 긴 리드타임, 동일공정 반복생산 등의 특징으로 인하여 효과적인 생산 스케쥴 작성에 많은 어려움을 겪고 있다. 최근 TOC 이론에서 제시하고 있는 DBR기법을 PCB 생산라인에 적용하고자 하는 시도는 진행되고 있으나, 제약공정을 1개만 설정하도록 하는 일반적인 DBR로서는 PCB 생산라인의 특성상 충분한 효과를 기대할 수 없는 현실이다. 따라서 본 논문에서는 PCB 생산라인에서 효과적인 생산스케줄링을 수립하기 위하여 TOC의 DBR기법을 발전시킨 복수 DBR기법을 제시하였다. 또, 실제로 국내 중소 PCB 제조업체에 복수 DBR을 적용하여 제조 리드타임을 20%이상 단축함을 확인하였다.

• 한국시뮬레이션학회논문지
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• 제22권2호
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• pp.21-31
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• 2013

진단 의료 혈액 분석기는 세계 의료기기 시장에서 지속적인 고성장세를 이어가고 있다. 본 연구에서는 국내 혈액분석기가 진단 의료기기 시장에서 가격경쟁력을 높여갈 수 있도록 비용을 절감시키면서 낮은 생산원가를 실현시킬 수 있는 생산성 향상 방안을 마련하는데 중점을 두었다. TOC 제약이론의 집중개선 5단계와 공장자동화 전략을 기반으로 시뮬레이션을 모델링하였으며 단계별로 대안을 제시하고 결과를 예측하여 분석하였다. ARENA 시뮬레이션을 이용하여 현장의 상황을 정확히 모델링하였으며 TOC 제약이론 집중개선 5단계를 도입하여 보다 체계적이고 효과적으로 개선하였다. 제약공정의 능력을 확장하는 단계에서는 적절한 공장자동화를 통하여 생산성을 크게 향상시켰으며 자동화 설비 도입에 따른 경제성 분석을 실시하여 투자대비 효과를 입증하였다.

• 한국정밀공학회지
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• 제16권11호
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• pp.174-182
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• 1999

This paper describes a research work of developing a computer-aided design of product with bending constraints and piercing for progressive working. an approach to the CAD system is based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written AutoLISP on the AutoCAD with a personal computer and is composed of four main modules, which are input and shape treatment, flat pattern layout, production feasibility check, and strip-layout module. Based on knowledge-based rules, the system is designed by considering several factors, such as radius and angle of bend, material and thickness of product, complexities of blank geometry and punch profile, bending sequence, availability of press. Strip layout drawing generated by piercing with punch profiles divide into automatically for external area is shown into graphic forms, including bending sequences for the product with piercing and bending constraints. Results obtained using the modules enable the designer and manufacturer of piercing and bending dies to be more efficient in this field.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.215-218
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• 1996

In work scheduling problems, scheduling constraints are not absolutely rigid; they may be changed depending on the scheduling aspect effected. In order to cope with changes in scheduling constraints and assignment strategies and to optimize scheduling results quickly, this paper will propose a new scheduling method which combines knowledge engineering and mathematical programming techniques.