• 한국정밀공학회지
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• 제23권5호
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• pp.93-102
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• 2006

This paper proposes a controller design analysis for three-axis CNC systems considering both contouring and tracking performance. The proposed analysis inclusively combines axial controllers for each individual feed drive system together with cross-coupling controller at the beginning design stage as an integrated manner. These two controllers used to be separately designed and analyzed since they have different control objectives. The proposed scheme includes a stability analysis for the overall control system and a performance analysis in terms of contouring and tracking accuracy. Computer simulation is performed and the results show the validity of the proposed methodology. Further, the results can be used as a basic guideline in systematic and comprehensive controller design for multi-axis CNC systems.

• 산업공학
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• 제12권4호
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• pp.514-531
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• 1999

This paper deals with the design of the manufacturing information system which is able to respond rapidly to various requirements of customers in make-to-order environment. The system is required to maintain a consistent flow of information from the start to the end. For this, we adopt an approach based on Information Engineering (IE) methodology, which consists of four stages: planning, analysis, basic design, and detail design. The first is a planing stage which establishes a project goal and organizes a project team. In the second stage, current activities are analyzed and problems are defined. The basic design is accomplished in the third stage, where a project scope is defined and an overall feature of the new system is presented. And then, in the last stage, the operation plan of each subsystem is drawn up in detail and all subsystems are integrated. This study applies the methodology to the case of H company and focuses on designing forms which are easy-to-write, easy-to-understand, and field-oriented. These forms are interrelated and can be used for systematic analysis and design. By applying them to the system design, we have obtained effect of reducing cost and time.

• 한국정밀공학회지
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• 제19권5호
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• pp.51-55
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• 2002

This paper presents a systematic methodology and formulation for determining optimal strategies of multi-body dynamic systems, which is based on multi-body dynamics, design sensitivity, and optimization techniques, and is applicable to a wide variety of mechanical systems. The particular application discussed in this paper considers a vehicle model with four-wheel steeling capability, and the presented methodology determines an optimal steering angle ratio strategy for the vehicle. It is shown that such a strategy can improve the ride stability of the vehicle, during a variety of maneuvers, when compared against similar strategies obtained from linear and simplified vehicle models.

• Journal of Advanced Marine Engineering and Technology
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• 제31권8호
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• pp.911-917
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• 2007

Global primary energy demand is projected to increase by 1.7% per year from 2000 to 2030. Almost three-quaters of the increase in demand will come from the transportation sector. Fuel cell hybrid vehicle technology has the potential to significantly reduce energy and harmful emissions, as well as our dependence on foreign oil. In this paper, a systematic and logical methodology is developed and improved mainly to design light duty fuel cell hybrid electric vehicle. We investigated structure and characteristics of light duty FC hybrid vehicle carefully. It can easily be expanded to analyze vehicle-to-grid power connectable plug-in NeHEV. A fuel cell hybrid neighbourhood electric vehicle configuration has been studied in-depth utilizing the proposed methodology.

• 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.

• 한국정밀공학회지
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• 제20권1호
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• pp.151-158
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• 2003

Design changes frequently occur while design activities are performed. If the impact of design changes is estimated, design efficiency can be improved. But, the types of design changes are various and they can affect other design parts. Hence, it is difficult to deal with design changes directly. The purpose of this research is to develop systematic algorithms for change propagation tracing and change impact analysis, and then to implement a change impact analysis system. We have selected a process-based design and a design environment which is composed of design parameters and constraints. The algorithm for change propagation tracing tracks the change propagation of design parameters and finds design parameters, constraints and tasks which are probably changed. In the algorithm for change impact analysis, a change impact value is calculated from the list of changeable tasks. These two algorithms have been implemented into change impact analysis system (CIAS). CIAS has been applied to the redesign of 2 stage gear drives. CIAS can improve the efficiency of design activities. If there are many alternatives for a design change at the redesign step, designers can calculate the change impact value of each alternative and perform design change activities in the direction of minimizing design change impact.

• 공학교육연구
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• 제1권1호
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• pp.27-32
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• 1998

학사과정 공학프로그램에서는 기초과학, 공학이론(engineering science), 공학설계(engineering design), 공학관련 인문학 및 사회과학 등 4개 분야를 다루어야 하는데 우리나라의 경우는 후자의 2개 분야를 제대로 교육하지 못하고 있다. 그 큰 이유는 이 분야 교과목 개발이 어렵고 그 교과목을 교육하기도 힘들기 때문이다. 그러나 우리의 교육여건이 점차 개선되고 있고 산업체에서도 강도높게 요구하고 있기 때문에 이들 2개 분야의 교육을 시급히 강화할 필요가 있다. 이 연구에서는 이들 2개 분야를 종합적으로 교육시킬 수 있는 하나의 설계교육 모델을 제안하였다. 설계교육을 세단계로 구성하였는데 제1단계는 공학의 본질 및 설계과정을 이해시키고, 창의력향상에 주안점을 둔 설계, 제2단계는 전공이론을 이용한 정밀하고 경제적인 해를 찾는 설계방법, 제3단계는 실사회 문제를 해결할 수 있는 설계능력을 배양하는 것으로 구성하였다. 그리고 각 전공교과목에서도 여러 지식을 종합하는 설계과제를 다루도록 하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.80-81
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• 2019

Change requests occur persistently in the construction phase of a construction project. The law requires that the contract amount be adjusted in accordance with the relevant regulations when there is a change in the construction amount due to the design change in the construction contract. SAVE international, on the other hand, defines the value methodology as a systematic and structured approach to improving projects, products and processes. Design Changes in the construction projects require organizational efforts to improve value and quality. However, the law does not include change requests in which the VE object is fixed and related data is collected and function analysis can be derived in a short time. Therefore, it is necessary to apply VE to the design change procedure, which can further improve the value of construction work. The application derived from this study need to be presented as simply as possible without compromising the basic concept of VE. If the application is extended to the field and proved to be effective, it is expected to contribute to the overall value of construction work.

• 대한전자공학회논문지SD
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• 제47권1호
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• pp.94-101
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• 2010

최근 여러 개의 프로세서 및 메모리를 한 개의 칩에 구현하여 다양한 알고리즘을 구현하는 Multi-Processor System-on-Chip (MPSoC) 설계가 가능해지면서, 프로세서 간 interconnection을 최적화 하는 문제가 중요해졌다. Application에 따라서 최적 interconnection이 다르기 때문에, 체계적으로 다양한 사양에 적합한 interconnection 구조를 설계하는 방법이 필요하다. 본 논문에서는 프로세서가 4~16개 정도인 MPSoC application에서는 버스 구조가 적절한 점에 주목하여, 간단한 arbitration이 특징인 Single Arbitration Multiple Bus Accesses (SAMBA) 형 버스 구조를 이용하여, 다양한 application에 대한 성능 제약 조건을 만족하는 저비용 버스 구조를 찾는 새로운 방법을 제안하였다. 다양한 Application을 실험에 이용하여, 제안한 방법으로 성능 제약 조건 내에서 저비용 버스 구조를 찾았다. 같은 성능으로 최적화 전의 구조에 비해서 버스 분할에 필요한 로직 사용이 경우에 따라 약 50% 이상 감소한다. 또한 다양한 성능 조건에 대한 저비용 버스 구조를 찾을 수 있었다.

• Advances in Computational Design
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• 제8권4호
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• pp.327-351
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• 2023

This article explores how multi-objective optimization techniques can be used to design cost-effective and structurally optimal spatial steel structures, highlighting that optimizing performance can be as important as minimizing costs in real-world engineering problems. The study includes the minimization of maximum horizontal displacement, the maximization of the first natural frequency of vibration, the maximization of the critical load factor concerning the first global buckling mode of the structure, and weight minimization as the objectives. Additionally, it outlines a systematic approach to selecting the best design by employing four different evolutionary algorithms based on differential evolution and a multi-criteria decision-making methodology. The paper's contribution lies in its comprehensive consideration of multiple conflicting objectives and its novel approach to simultaneous consideration of bracing system, column orientation, and commercial profiles as design variables.