• Journal of the Society of Naval Architects of Korea
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• v.36 no.1
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• pp.82-89
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• 1999

A designer must make a lot of decisions in a design process. The decisions may be classified into selection decisions and compromise decisions. As the results of two decisions depends on the designer's intention it is necessary that the designer's intention should be reflected in the design systematically and precisely. As the AHP(Analytic Hierarchy Process) technique analyzes and evaluates a obscure selection problem hierarchically, designer's intention can be reflected in the design systematically. Also as qualitative attributes can be rated at quantitative criterion the designer's intention can be reflected consistently. Usually an engineering problem is a coupled problem in which a designer must select one alternative from a set of alternatives and find optimal characteristics of the alternative concurrently. As considered attributes are functions of the compromise system variables and the attributes's units and orders are different each other, attribute ratings must be normalized. This paper introduces a neural network at this normalization. So the attribute ratings can reflect designer's intention and the knowledge from his(her) experience automatically.

• Journal of KIISE:Software and Applications
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• v.27 no.2
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• pp.120-133
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• 2000

Major obstruction of using formal methods for hybrid real-time systems in industry is the difficulty that engineers have in understanding and applying the quantitative methods in an abstract requirements phase. While formal methods technology in safety-critical systems can help increase confidence of software, difficulty and complexity in using them can cause another hazard. In order to overcome this obstruction, we propose a framework for qualitative requirements engineering of the hybrid real-time systems. It consists of a qualitative method for requirements specification, called QFM (Qualitative Formal Method), and a safety analysis method for the requirements based on a causality information, called CRSA (Causal Requirements Safety Analysis). QFM emphasizes the idea of a causal and qualitative reasoning in formal methods to reduce the cognitive burden of designers when specifying and validating the software requirements of hybrid safety systems. CRSA can evaluate the logical contribution of the software elements to the physical hazard of systems by utilizing the causality information that is kept during specification by QFM. Using the Shutdown System 2 of Wolsong nuclear power plants as a realistic example, we demonstrate the effectiveness of our approach.

• Journal of Convergence for Information Technology
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• v.10 no.3
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• pp.48-57
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• 2020

This study focuses on the development of simple qualitative indicators for evaluating and selecting innovation leading companies that challenge National Award. Another purpose of this study is to complement the aspect in which the innovative or value of the companies' products, technologies, and services is only quantitatively evaluated. Existing evaluation indicators of national award have too many evaluation items and were not suitable for innovation-based company evaluation. The research approach is to select category for developing qualitative indicators based on previous studies and TF discussion. From the input-process-output-outcome point of view, we have set up an indicator system as a series of flows. Finally, five categories such as creativity, system excellence, customer value, performance, and ripple effects are selected as qualitative indicator. For these selected indicators, conceptual definitions and the main points of evaluation are described. And the system level evaluation and the ADLI approach are presented for reference. The appendix also includes examples of qualitative and quantitative evaluation of real companies using these indicators. However, this study implies the possibility that the evaluation results may vary depending on the level and perspective of the evaluator. We hoped that detailed research on candidate indicators that can be used as qualitative indicators and research on the development of mixed indicators(qualitative and quantitative) will continue in the future.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1138-1146
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• 1990

A knowledge-based expert system has been developed implementing the ambiguous process of conceptual design of flywheels in earlier design stage to assist the selection of proper flywheel types and dimensions. Knowledge for the flywheel design consists of the rules for conventional as well as super flywheels and other informations required for the design process. Those knowledges were extracted from literatures and some experts in the field. With these knowledges, an integrated knowledge based expert system was developed to help users with informations and facilities to design flywheels interactively using a commercial package of knowledge-based system called INSIGHT2 of backward chaining and proprietary package of forward chaining written in LISP language. The developed system consists of the knowledge base part and calculation park : the first one consists of main module and user level modules and the other one is to assist in analyzing the stress distribution in the flywheels and deciding the flywheel dimensions and specifications for various types of flywheels using proper data bases and graphic facilities. With this flywheel design software, several examples were tried generating acceptable design results.

• Tunnel and Underground Space
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• v.29 no.1
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• pp.30-37
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• 2019

Some leading countries in mining have a very quantitative guideline for underground mine opening design which is useful to minimize mine hazards such as rockfall and collapse. Those hazards sometimes can cause a huge damage on human life and property in the mines. Construction guidelines of underground mines in Korea consist of qualitative and general expressions although the workers' safety rules and guides are well provided. Recently, mining operations in Korea are going underground due to the environmental regulations and resource depletion at shallow depth, and therefore there is a growing demand on a specialized and systematic guideline for mine opening design securing the underground stability. In this paper, current status of mining industry, research trends, and mining guidelines in Korea and overseas have been reviewed to give an insight into developing a new Korean guideline for underground mine design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1434-1439
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• 2012

Vehicle is a dynamic system combined with various parameters. Dynamic characteristics of a vehicle can vary with the change of these parameters. To investigate the effect of the design parameter on vehicle handling performance the sensitivity analysis is carried out by the numerical method. The vehicle model is described by equivalent cornering stiffness that considers parameters of suspension and steering system. As the analysis results show the effect on the static and dynamic characteristics of the vehicle system, the sensitivity analysis can be used for synthesis of the design parameters to improve the vehicle handling characteristics at the design stage as well as during the vehicle test under development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.9
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• pp.805-815
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• 2007

In order to build a conceptual design program for a liquid rocket engine system, performance based sub-programs for each core component of the engine system were made. Parts included were the combustion chamber, supersonic nozzle, centrifugal pump, and impulsive turbine. Simple mathematical models based on classical thermodynamic and inviscid theories were adopted with proper tuning by empirical data. In Part I, aiming to validate each sub-program, we examined the results of each program qualitatively, and parametrically investigated the sensitivity due to the change in design parameters.

• Journal of Korean Society of Transportation
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• v.18 no.2
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• pp.17-26
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• 2000

LOS(Level of Service), the qualitative measure describing operational condition of highway, must be evaluated as quantative index in terms of user service. So, This study is focused on developing the user cost function that user cost is measured in the variation of V/C, MOE(Measure of Effectiveness) of LOS in basic Section of highway. The user cost is calculated as the sum of accident cost, operation cost, travel time cost. The data is collected in the four basic section of Singal-Ansan and Jung bu Highway. As the result of user cost function analysis, the user cost is the lowest When V/C is 0.54. Considering the V/C ratio(0.7) of Basic Section in rural highway suggested in KHCM, We find out that the LOS suggested KHCM increase the user cost of highway.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.05a
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• pp.55-63
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• 1994

국내에서 실제 운전되고 있는 천연가스 복합발전플랜트의 성능 예측에 대한 공정전산 해석을 수행하였다. 가스터빈 사이클은 압축기, 연소기, 터빈 및 터빈 날개의 냉각을 위한 냉각계통으로 구성하였으며, 중기터빈 사이클은 폐열회수보일러, 고압/중압/저압터빈, 펌프 및 부속공정으로 구성하였다. 해석결과는 실제 플랜트의 운전자료와 정성적 및 정량적으로 잘 일치하였으며, 폐열회수보일러의 적절한 설계에 의하여 전체 플랜트의 출력향상을 도모할 수 있음을 제시하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.297-302
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• 1998

최근 원자력산업계 동향은 기기의 노후화, 예비품 확보의 어려움, 그리고 기존 설비에 대한 보수비용 증가 등의 이유로 아날로그 계측제어 설비들을 컴퓨터-기반 설비로의 부분적인 개선이나 전체적인 교체가 추진되고 있다 그러나 컴퓨터-기반 설비는 소프트웨어와 하드웨어가 환경영향에 민감하고, 공통모드고장을 일으킬 수 있는 프로그래밍 설계오류의 잠재성이 있는 것으로 알려져 있다. 공통모드고장을 방지할 수 있는 가장 설득력 있는 해결방안은 철저한 품질보증, 심층방어 및 다양성 설계기법으로 평가되고 있다. 본 논문에서는 컴퓨터-기반 계측제어계통의 심층방어 및 다양성에 관한 규제기준과 정성적 평가를 위한 블록개념을 소개하고, 평가의 사례로서 CE System 80+와 국내 가동중인 W형 원전의 설비개선에서 주급수 상실시 컴퓨터-기반 설비의 공통 모드고장에 따른 다양성과 심층방어계층을 평가하였다. 특히 국내 가동중인 W형 원전에 대해서는 그 평가결과를 근거로 하여 ATWS 완화설비의 설치를 제안하였다.