• Journal of Power Electronics
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• 제16권1호
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• pp.319-328
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• 2016

In this study, we first briefly introduce the effect of circulating current control on the modulation signal of a modular multilevel converter (MMC). The maximum modulation index is also theoretically derived. According to the optimal modulation index analysis and the model in the continuous domain, different DC-side output impedance equivalent models of MMC with/without compensating component are derived. The DC-side impedance of MMC inverter station can be regarded as a series xR + yL + zC branch in both cases. The compensating component of the maximum modulation index is also related to the DC equivalent impedance with circulating current control. The frequency characteristic of impedance for MMC, which is observed from its DC side, is analyzed. Finally, this study investigates the prediction of the DC voltage ripple transfer between two-terminal MMC high-voltage direct current systems under unbalanced conditions. The rationality and accuracy of the impedance model are verified through MATLAB/Simulink simulations and experimental results.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.38-43
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• 2021

Permanent magnet linear synchronous motor (PMLSM) is suitable for use in cleanroom environments and have advantages such as high speed, high thrust, and high precision. If the stators are arranged in the entire moving path of the mover, there is a problem in that the installation cost increases. To solve this problem, discontinuous armature arrangement PMLSM has been proposed. In this case, the mover receives a greater detent force in the section where the stator is not arranged. When a large detent force occurs, it appears as a ripple component of the thrust during PMLSM operation. If the shape of the stator is changed to reduce the detent force, the characteristics of the back EMF are changed. Therefore, in this paper, the detent force and the harmonic components of back EMF were reduced through multi-purpose shape optimization. To this end, the FEA model was constructed and main effect analysis was performed on the major shape variables affecting each objective function. Then, the optimal shape that minimizes the objective function was derived through the response surface analysis method.

• 인터넷정보학회논문지
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• 제21권3호
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• pp.71-81
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• 2020

디지털바이오헬스케어 산업은 문재인 정부의 3대 중점육성산업의 하나이다. 본 연구의 목적은 디지털바이오헬스케어산업의 연관 산업에 대한 파급효과와 투자효과를 비교분석하는 것이다. 디지털바이오헬스케어산업의 연관산업에 대한 파급효과를 분석하는 것은 산업 및 기술개발 정책의 수립에 매우 중요하다. 연구방법은 첫째, 표준산업분류 상의 33개 산업을 재분류하여 35개 산업대분류표로 재작성하였다. 둘째, 산업연관표의 분석틀을 활용하여 각종 유발계수와 파급효과계수들을 재작성하였다. 셋째, 디지털바이오헬스케어산업의 생산, 투자, 부가가치, 일자리부문에서 연관산업에 대한 파급효과를 비교하였다. 넷째, 투자효과측면에서 자체산업과 연관 산업과의 효과를 비교하였다. 이 연구의 결과가 산업정책 및 기술개발정책 수립에 용이하게 활용되기를 기대한다.

• 한국건설관리학회논문집
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• 제6권5호
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• pp.69-77
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• 2005

Change is inevitable and is a reality of construction projects. Most construction contracts include change clauses and allowing contractors an equitable adjustment to the contract price and duration caused by change. However, the actions of a contractor can cause a loss of productivity and furthermore can result in disruption of the whole project because of a cumulative or ripple effect. Because of its complicated nature, it becomes a complex issue to determine the cumulative impact (ripple effect) caused by single or multiple change orders. Furthermore, owners and contractors do not always agree on the adjusted contract price for the cumulative Impact of the changes. A number of studies have attempted to quantify the impact of change orders on project costs and schedule. Many of these attempted to develop regression models to quantify the loss. However, regression analysis has shortcomings in dealing with many qualitative or noisy input data. This study develops ANN models to classify and quantify the labor productivity losses that are caused by the cumulative impact of change orders. The results skew that ANN models give significantly improved performance compared to traditional statistical models.

• 정보관리연구
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• 제42권3호
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• pp.55-69
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• 2011

현대 과학기술연구개발에서 데이터의 수집, 큐레이션, 분석, 시각화의 효율화는 과학기술발전의 중요한 요소이다. 데이터 집중연구에서 이러한 과학데이터의 가치는 절대적으로 필요하다고 할 수 있다. 과학데이터의 생산량은 기하급수적으로 증가했지만 데이터를 수집하고 배포할 수 있는 수단을 마련하는 측면에서 보면, 현재 분야별로 과학데이터의 개별적인 활용 체제만 운영되고 있어 걸음마 단계이다. 이에 본 논문에서는 국가차원의 국가 과학데이터센터 구축의 경제적 파급효과를 한국은행(2009)의 산업 연관분석을 이용하여 생산유발효과, 부가가치유발효과, 취업자유발효과 및 전 후방연쇄효과로 나누어 분석하여 국가 과학데이터센터 구축에 대한 경제적 타당성을 검증하고자 한다.

• 수산경영론집
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• 제53권3호
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• pp.65-83
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• 2022

In addition to simply providing quality food to the people, the fishery industry must be maintained and developed because it has various functions such as national food security, preservation of natural scenery, protection of national territory, and revitalization of the local economy. However, risk factors such as climate changes and environmental destruction have raised concerns about the sustainable development of the industry. Since these risk factors are becoming larger and more complex over time, it is time to conduct research related to the risk of the fishery industry. Therefore, the purpose of this study is to explore the risk factors facing the fisheries at this point, to analyze the economic ripple effect of regional fishery product supply shortage, and to draw implications. As a result of this study, the economic ripple effect of fishery product shortage per won was highest in Busan, followed by Gangwon, Gyeongnam, and Gyeongbuk. Considering the size of the local fishery industry, Busan had the highest supply shortage per 1% of local fisheries production. It is also necessary to prepare special risk management and countermeasures for these regions since the effect of supply shortage in regions such as Jeonnam, Gyeongnam, and Jeju is large compared to other regions.

• 보건행정학회지
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• 제30권4호
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• pp.438-443
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• 2020

The digital treatment technology industry is one of the core fostering industries of the Moon Jae-in government along with the global trend. The purpose of this study is to compare and analyze the investment and economic ripple effect on the related industries. To this end, we used the industry-related table, which is the actual measurement data for 2015 that the Bank of Korea actually measured and released every 5 years in 2019. The digital treatment technology industry was not clearly classified within Korea's industrial classification system, so the contents of the industry-related survey were analyzed, and the digital treatment technology industry was reclassified and then analyzed. As a result of the analysis, it was analyzed that the production induction effect of the digital treatment technology-related industry in 2015 was 1.770, the value-added induction effect was 0.875, and the employment induction effect was 19.128, which was higher than that of other industries in Korea. As a result of the analysis of the economic ripple effect (scenario 1), the production inducing effect was about 370 billion won, the added value inducing effect was about 185 billion won, and the employment inducing effect was 4,044 people. The results of this study are expected to play a large role in economic revitalization as the effect of inducing production, increasing employment, and creating added value through fostering the digital treatment technology industry is expected to play a large role in activating the economy. It is expected to play a large role in providing central medical services. Therefore, it is expected that policy support for revitalizing the digital treatment technology industry through active investment support and tax benefits from the government to foster the digital treatment technology industry is necessary.

• 대한교통학회지
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• 제28권1호
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• pp.107-114
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• 2010

본 논문은 국가 경제의 동맥역활을 하는 물류산업에 초점을 맞추고 권역별 물류산업의 특징과 경제적 파급효과를 분석하였다. 이를 위하여 물류산업을 중심으로 6개 권역(수도권, 강원권, 충청권, 전라권, 경북권, 경남권)으로 구분된 지역산업연관표(MRIO표)를 이용하여 지역별, 산업별로 경제권에 대한 분석을 수행하였다. 연구의 목적에 맞게 기존의 산업연관표를 중심으로 29개 부문으로 재구성하였고, 총산출액 비교 및 외생화 방법을 이용하여 생산유발효과, 공급지장효과, 전후방연쇄효과 등을 분석하였다. 분석결과, 물류산업은 생산유발효과보다 공급지장효과가 큰 산업으로 나타났고, 지역간의 거래보다는 지역내의 거래가 상대적으로 많은 것으로 나타났다. 그 밖에 수도권 물류산업은 중간수요적 원시산업 특성을 가지는 관계로 파급효과가 미약한 것으로 나타났고, 경남권의 자동차 및 석유화학, 전라권의 석유화학 등에 미치는 물류산업의 파급효과가 큰 것으로 나타났다.

• Journal of Power Electronics
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• 제19권6호
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• pp.1366-1379
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• 2019

High-gain DC/DC converters have become one of the key technologies for the grid-connected operation of new energy power generation, and its research provides a significant impetus for the rapid development of new energy power generation. Inspired by the transformer effect and the ripple-suppressed ability of a coupled inductor, a double-coupled inductor high gain DC/DC converter with a ripple absorption circuit is proposed in this paper. By integrating the diode-capacitor voltage multiplying unit into the quadratic Boost converter and assembling the independent inductor into the magnetic core of structure coupled inductors, the adjustable range of the voltage gain can be effectively extended and the limit on duty ratio can be avoided. In addition, the volume of the magnetic element can be reduced. Very small ripples of input current can be obtained by the ripple absorption circuit, which is composed of an auxiliary inductor and a capacitor. The leakage inductance loss can be recovered to the load in a switching period, and the switching-off voltage spikes caused by leakage inductance can be suppressed by absorption in the diode-capacitor voltage multiplying unit. On the basis of the theoretical analysis, the feasibility of the proposed converter is verified by test results obtained by simulations and an experimental prototype.

• 전기전자학회논문지
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• 제23권1호
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• pp.254-260
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• 2019

본 논문에서는 양방향 dc-to-dc 컨버터의 고장원인, 고장영향, 고장 결과를 파악하기 위한 failure mode and effect analysis(FMEA)와 양방향 컨버터의 위험도를 고려한 fault-tree analysis(FTA)를 통해 고장률을 예측한다. 전기차의 구동전압을 효율적으로 상승시키기 위해 인버터 앞단에 부착되는 양방향 컨버터는 배터리 전력을 dc-link 커패시터로 방전시키는 승압모드와 회생전력을 배터리로 충전시키는 강압모드를 가진다. 양방향 컨버터의 동작 특성을 고려한 FMEA 결과를 바탕으로 컨버터의 위험도를 고려한 고장나무를 설계한다. 전기차 MCU용에 맞는 설계 파라메타를 설정하고 출력전압 리플과 인덕터 전류 리플에 따른 커패시터와 인덕터의 부품 고장률을 분석한다. 또한 동작 온도에 따른 주요부품의 고장률을 MIL-HDBK-217F를 이용하여 구한다. 마지막으로 부품 고장률을 고장나무의 기본 사상의 고장률로 반영하여 컨버터 고장률과 평균고장시간을 예측한다.