• 시스템엔지니어링워크숍
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• 통권1호
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• pp.32-39
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• 2003

This work describes a study of analysis and evaluation activities applied systems engineering approach. It is presented technique of derivation and management requirement. A scheme of the defence project analysis and evaluation using a systems engineering process is described.

• 항공우주시스템공학회지
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• 제12권4호
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• pp.26-34
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• 2018

이륙 중량 25 kg급 멀티콥터용으로 개발된 프로펠러에 대해 정적 구조 시험 및 성능 시험을 통해 설계 요구도 충족 여부를 판별하기 위한 시험 평가를 수행하였다. 정적 구조 시험에서는 극한 하중 및 요구도 하중 부가 후 시편 파손이 발생하지 않음으로써 프로펠러 구조 강도에 대한 안전 여유 3 이상을 갖는 것으로 나타났다. 성능 시험에서는 설계 요구도의 제자리 비행 추력 및 최대 추력을 발생시키고, 운용 추력 영역에서 제자리 비행 성능 효율은 0.73 이상을 나타내었다. 기준 프로펠러와 비교할 때, 성능 효율 최대값은 3% 이상 증가되고, 소비 전력은 운용 영역에서 4% 이상 저감되는 것으로 나타났다. 구조 강도 요구도 및 성능 요구도를 충족시킴으로써 프로펠러는 성공적으로 개발된 것으로 평가되었다.

• 한국유체기계학회 논문집
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• 제3권4호
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• pp.7-14
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• 2000

This paper provides integrity evaluation and root cause analysis for defects observed at volute tongue, or cutwater, of the operating centrifugal pump in power plant. The cause of the cracks are analyzed and reviewed from the viewpoint of the operation and maintenance of the pumps, and the sample obtained from the cracked volute tongue of the pump are examined. At first, in-situ hardness test and microstructure examination were performed to understand the cause of cracking at volute tongue. The evaluation of structural integrity and the possibility of the crack propagation is also evaluated. Cracks were typical intergranular cracking and propagated along with prior austenite grain boundary. At easing volute tongue, the hardness was higher than ASTM requirement and a large amount of intergranular Cr carbide was precipitated. These were due to high C content in material. P content was also higher than ASTM requirement. Therefore, Cr carbide precipitation and P segregation at grain boundary, caused by higher C and P content in material, resulted in intergranular cracking of casing volute tongue. This procedure for integrity evaluation and root cause analysis is used to guide, and support the pump designer and manufacturer's material selection and process design to avoid a costly, unplanned outage of plant.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1276-1280
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• 2005

The Maglav system project affects communities and are usually funded by public agencies. Evaluation of this project that considerably impact whole communities requires public involvement. This specific requirement of transportation projects determines the method of their evaluation as the impacts are estimated from the transportation economic point of view. Especially evaluation criteria must reflect the needs of the interested parties and should consider all foreseeable benefits and losses caused by the Maglav project. To select evaluation criteria and evaluation method may help a decision--maker in making a best selection for a Maglav project.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1397-1405
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• 2017

As the introduction of wind power is steadily increasing, negative effects of wind power become more important. To operate a power system more reliable, the system operator needs to recognize the maximum required capacity of available generators for a certain period. For recognizing the maximum capacity, this paper proposes a methodology to determine an optimal reserve requirement considering wind power, for the certain period in the mid-term perspective. As wind speed is predicted earlier, the difference of the forecasted and the actual wind speed becomes greater. All possible forecast errors should be considered in determining optimal reserve, and they are represented explicitly by the proposed matrix form in this paper. In addition, impacts of the generator failure are also analyzed using the matrix form. Through three main stages which are the scheduling, contingency and evaluation stages, costs associated with power generation, reserve procurement and the usage, and the reliability cost are calculated. The optimal reserve requirement is determined so as to minimize the sum of these costs based on the cost/reliability analysis. In case study, it is performed to analyze the impact of wind power penetration on the reserve requirement, and how major factors affect it.

• 품질경영학회지
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• 제30권1호
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• pp.162-171
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• 2002

A practical algorithm of generating most probable states in decreasing order of probability, given the probability of each unit\`s state, is suggested for approximating reliability(performability) evaluation of a network with multistate(multimode) units. Method of approximating network reliability for a given measure with most probable states is illustrated with a numerical example. The proposed method in this paper is compared with the previous method regarding memory requirement. Our method has some advantages for computation and achieves improvement with regard to memory requirement for a certain condition judging from the computation experiment.

• Asian-Australasian Journal of Animal Sciences
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• 제33권5호
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• pp.679-695
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• 2020

Evaluating amino acid requirements, specifically threonine requirements, in horses will enable better feed formulation and result in economic production, improved animal health, and reduced environmental pollution. However, the current knowledge of protein and amino acid requirements in horses is still limited. Because horses have a unique digestive system and consume a variety of feed ingredients, their protein digestibility may be affected than other species by different feed composition, and thus amino acid requirements are susceptible to vary between situations. Therefore, a careful evaluation of amino acid requirements with a proper method is needed for various conditions. This review will also provide comprehensive information that needs to be considered when designing an amino acid requirement study in horses.

• 대한조선학회논문집
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• 제44권4호
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• pp.459-465
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• 2007

This paper deals with the development of measuring methodology and the requirement for its evaluation of the infrared radiation from a naval ship to optical sensors, considering the Meteorological conditions. Factors required for measuring the apparent temperature and infrared radiation are identified and two methods are suggested based on the measuring instruments carried by ship or aircraft. and target operation in the Meteorological conditions is considered. This study describes some factors affecting the IR signature. required instruments to obtain the IR signal considering the naval ship.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 춘계학술발표회요약집
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• pp.467-467
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• 1999

• Journal of Biosystems Engineering
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• 제20권3호
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• pp.275-287
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• 1995

The rice processing complex(RPC) consisted of the rice handling, drying, storage, and milling processes. It has been established at 83 locations domestically by April 1994, and 200 of RPC will be built more throughout the country. Therefore, this study has been performed to achieve two objectives as the followings : 1) Development of mathematical models which can assess the requirement of electricity, fuel, and labor for four model systems of rice processing complex. 2) Development of a computer simulation model which produce the improved designs of RPC by the evaluation results of energy requirements of four RPC models. The results from this study are summarized as follows : 1) Mathematical models were developed on the basis of result of mass balance analysis and required power of machines for each process. 2) A computer simulation model was developed, which can produce the improved designs of RPC by the evaluation results of energy requirements. The computer simulation model language was BORLAND $C^{++}$. 3) The results of simulation showed that total energy requirements were ranged from 75.94㎾h/t to 124.30㎾h/t. 4) From the results of computer analysis of energy requirement classified by drying type, it was found that energy requirement of the drying type A{paddy rice (PR) for storage-natural air drying(15%), PR for milling-heated air drying(16%)} were less than that of the drying type B{1 step-natural air drying(PR for storage : 18%, PR for milling : 20%), 2 step-heated air drying(PR for storage : 15%, PR for milling : 16%)}. 5) The energy efficient drying method is that all the incoming rough rice to RPC should be dried by national air drying systems. If it is more than the capacity of national air drying system, the amount of surplus rough rice is recommended to be dried by the heated air drying method.