• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.207-215
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• 2004

There are various characteristics called for in work roll and intermediate rolls for cold rolling mills. Among these characteristics, the two main requirements are to ensure the quality of the rolled products and to reduce roll cost. To achieve these needs, resistance to wear, to thermal shock and to contact fatigue are especially important. This paper describes that new material(named DSR1) for intermediate rolls which greatly increases rolling campaign and improves resistance to wear has been developed. DSR1 was successfully manufactured and has been used in the cold rolling mill. It showed that Trial product was homogenous in hardness distribution and sufficient usable diameter. Also in service test, trial product is much more excellent rolling performance than conventional $5\%Cr$.

• 한국가스학회지
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• 제8권4호
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• pp.15-22
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• 2004

본 연구는 LNG 기지 내 주요 프로세스 설비인 LNG 고압펌프의 운전유량 및 토출압력을 조절함으로서 공정운영 조건을 개선하기 위해 수행되었다. 공정 해석 시뮬레이터인 ASPEN PLUS를 사용한 고압펌프의 실제 운전 성능분석 및 천연가스 송출부하 분석을 통하여 계절별 적정 LNG 고압펌프 토출유량을 결정하였고 그 결과는 현장운전에 적용되었다. 이로 인하여 고압펌프 소모 전력비용을 낮출 수 있으며, LNG기지 내 운영 프로세스 압력을 감소 시켜 보다 안전적인 기지운영을 유도할 수 있었다.

• 센서학회지
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• 제33권2호
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• pp.93-97
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• 2024

With the development of promising future mobility and urban air mobility (UAM) technologies, the demand for LIDAR sensors has increased. The SWIR photodetector is a sensor that detects lasers for the 3D mapping of lidar sensor and is the most important technology of LIDAR sensor. An SWIR photodetector based on QDs in an eye-safe wavelength band of over 1400 nm has been reported. QDs-based SWIR photodetectors can be synthesized and processed through a solution process and have the advantages of low cost and simple processing. However, the organic ligands of QDs have insulating properties that limit their ability to improve the sensitivity and stability of photodetectors. Therefore, the technology to replace organic ligands with inorganic ligands must be developed. In this study, the organic ligand of the synthesized PbS QDs was replaced with a MAPI inorganic ligand, and an SWIR photodetector was fabricated. The analysis of the characteristics of the manufactured photodetector confirmed that the photodetector based on MAPI-capped PbS QDs exhibited up to 26.5% higher responsivity than that based on organic ligand PbS QDs.

• 항공우주시스템공학회지
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• 제9권2호
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• pp.41-46
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• 2015

The various risk factors that affected schedule, costs and mission success, etc. in development of the satellite. This paper derives the considerable "Cost of Quality" factors in the satellite development phase through the survey of practical techniques in respect of measurement of quality cost in the commercial products manufacturing, and proposes mitigation strategy of quality cost using the approach that can be minimized it.

• 산업경영시스템학회지
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• 제29권3호
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• pp.135-142
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• 2006

Engineers are always concerned with life cycle costs for making important economic decisions through engineering action like reliability of products. Decisions during the reliability growth development of products involve trade-offs between invested costs and its returns. In order to find minimal LCC containing the reliability improvement cost, production cost, repair and replacement costs, and holding cost of spare parts for failure items we suggest in this paper relationship between development cost and sustaining cost in values of growth parameter $\beta$ of AMSAA model. This model is applied to the reliability growth program based on AMSAA model during R&D phase, the warranty activities of items and the block replacement policy for maintenance of items in avionic equipment.

• KIEE International Transactions on Power Engineering
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• 제11A권4호
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• pp.21-26
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• 2001

As competition is introduced in the electricity supply industry, congestion becomes a more important issue. Congestion in a transmission network occurs due to an operating condition that causes limit violations on the transmission capacities. Congestion leads to inefficient use of the system, or causes additional costs (Congestion cost). One way to reduce this inefficiency or congestion cost is to control the transmission flow through the installation of UPFC (Unified Power Flow Controller). This paper also deals with an optimal siting of the UPFC for reducing congestion cost by using shadow prices. A performance index for an optimal siting is defined as a combination of line flow sensitivities and shadow prices. The proposed algorithm is applied to the sample system with a condition, which is concerning the quadratic cost functions. Test results show that the siting of the UPFC is optimal to minimize the congestion cost by the proposed algorithm.

• 한국산림과학회지
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• 제59권1호
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• pp.9-14
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• 1983

본(本) 연구(硏究)는 I.B.R.D. 차관(借款)에 의해 실시(實施)된 연료림조성사업(燃料林造成事業)으로 인하여 발생(發生)하는 편익(便益)과 비용(費用)을 비교(比較)함으로써 사업(事業)의 수익성(收益性) 또는 투자효율(投資效率)을 판정하여 경제성(經濟性)을 검토(檢討)하기 위하여 실시(實施)되었다. 조사지역(調査地域)을 선정(選定)하여 조사(調査)한 자료(資料)와 그 외 관계자료(關係資料)를 이용(利用)하여 B/C율(率)과 IRR(내부투자수익율(內部投資收益率)방법(方法)에 적용(適用)한 결과(結果) 다음과 같은 결론(結論)을 얻었다. 1) 연료림(練料林)의 경제성(經濟性) 분석(分析)에 있어서 연료림(練料林)의 생산가액(生産價額)을 연탄가격(煉炭價格)으로 환산(換算)했을 때, B/C율(率)은 할인율(割引率) 6%에서 1.18, IRR은 12.2%로 수익성(收益性)이 있는 것으로 평가(評價)되었다. 2) 농촌임금(農村賃金)의 년평균(年平均) 27% 상승요인(上昇要因)에 의한 감응도분석(感應度分析)에 있어서 B/C율(率)은 1.07, IRR은 9.2%로 낮은 수익성(收益性)이 있는 것으로 평가(評價)되었다. 3) 연탄가격(煉炭價格)의 년평균(年平均) 26% 상승요인(上昇要因)에 의한 감응도분석(感應度分析)에 있어서 B/C율(率)은 1.34, IRR은 15.7%로 높은 수익성(收益性)이 있는 것으로 평가(評價)되었다. 4) 연료림조성사업(練料林造成事業)의 간접효과(間接效果)를 가산(加算)하면 경제적(經濟的) 효과(效果)는 더 높다고 할 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1658-1660
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• 2004

Use of higher voltage and higher capacity of power systems and their equipment is leading to an increase in the size of the entire system. In order to reduce the cost of constructing a substation, it is necessary to reduce the size of equipment. So, this paper described optical sensor, which exploited the electric and magnetic potentiometer to sense the measured voltage and current of medium voltage GIS. It can be used both in measurement and in protection relays as its well linearity, rapid response, broad dynamic range, wide frequency band, no magnetic saturation, small in volume, light weight, and saft in insulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.2210-2212
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• 1997

A sensorless input current controller for three phase PWM converter is proposed. A merit of this controller is that sinusoidal input line current, unity power factor, and ripple-free DC voltage can be achieved with low-cost. The paper describes the proposed control strategy and its implementation. Simulation result for the proposed controller is compared with that of the sensor based version.

• 산업공학
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• 제15권4호
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• pp.460-473
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• 2002

The objective of this paper is to design a Goal Alternatives Disposition System having three main subsystems for setting, evaluating and selecting goal alternatives. For setting of goal alternatives, System Alternatives Tree(SAT) structure will be developed, which has a computation algorithm for setting decision alternatives by the concept of System Priority Number(SPN). For evaluating and selecting of goal alternatives; First, Normative and Exploratory Priority Indices which consider technical performance to the goal, cost and feasibility are developed respectively. Second, Integrated Priority Index is built up to determine the total priority of the Goal Alternatives Disposition(GAD) system. For the design and verification of the GAD system, technological forecasting structure theory, systems engineering methodology will be used.