• Journal of Power Electronics
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• 제13권4호
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• pp.647-655
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• 2013

In this paper, an approach to reduce the common-mode voltage and to eliminate narrow pulse for implemented AC-DC matrix converters is presented. An improved space vector modulation (SVM) strategy is developed by replacing the zero space vectors with suitable pairs of active ones. Further, while considering the commutation time, the probability of narrow pulse in the conventional and proposed SVM methods are derived and compared. The advantages of the proposed scheme include: a 50% reduction in the peak value of the common-mode voltage; improved input and output performances; a reduction in the switching loss by a reduced number of switching commutations and a simplified implementation via software. Experimental results are presented to demonstrate the correctness of the theoretical analysis, as well as the feasibility of the proposed strategy.

• Smart Structures and Systems
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• 제2권4호
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• pp.339-355
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• 2006

A procedure to retrofit existing essential facilities subjected to seismic excitation is proposed. The main features of this procedure are to reduce maximum acceleration and associated forces in buildings subjected to seismic excitation by reducing their strength (weakening). The weakening retrofit, which is an opposite strategy to strengthening, is particularly suitable for buildings having overstressed components and foundation supports or having weak brittle components. However, by weakening the structure large deformations are expected. Supplementaldamping devices however can control the deformations within desirable limits. The structure retrofitted with this strategy will have, therefore, a reduction in the acceleration response and a reduction in the deformations, depending on the amount of additional damping introduced in the structure. An illustration of the above strategy is presented here through an evaluation of the inelastic response of the structure through a nonlinear dynamic analysis. The results are compared with different retrofit techniques. A parametric analysis has also been carried out to evaluate the effectiveness of the retrofitting method using different combination of the performance thresholds in accelerations and displacements through fragility analysis.

• 한국산림과학회지
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• 제101권4호
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• pp.606-612
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• 2012

기후변화협약 제16차 당사국총회에서 결정된 칸쿤 합의문의 REDD+ 결정문과 노르웨이의 인도네시아 REDD+ 국가 전략을 평가하기 위한 중요 요소를 바탕으로 인도네시아의 REDD+ 전략을 사전에 평가하기 위한 4가지 정성적인 기준을 개발하였다. '산림전용 및 산림황폐화의 원인 규명'(평가기준 1)과 '국가 MRV 체계 수립'(평가기준 2)은 REDD+가 성공할 수 있는 토대이다. '실질적인 온실가스 감축'(평가기준 3)은 REDD+의 궁극적인 목적이고 지역주민 및 원주민의 권리를 보장하고 생물다양성을 보장하는 '안전장치의 보장'(평가기준 4)은 REDD+의 보완적인 목적이자 REDD+ 성공의 토대라 할 수 있다. 본 연구에서 개발한 REDD+ 평가를 위한 기준 및 지표는 인도네시아뿐만 아니라 개도국의 REDD+ 국가 전략을 이해하기 위한 기본 틀을 제공한다.

• 한국환경과학회지
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• 제5권2호
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• pp.229-241
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• 1996

This study was performed to find the most desirable emission reduction for each mobile source pollutant and the optimal control strategy at a given level of expenditures in Pusan City in 2000 by using the interactive s-constraint method developed by Chang-Hyo Lee and Hyung-Wook Kim, which isone of the mathematical programming models. The most desirable emission reduction is 7093 ton/year for particulate (TSP), 4871 ton/year for NOx, 5148 ton/year for HC and 36779 ton/year for CO. The optimal control strategy is as follows; 1. As to passenger car and taxi, limiting VKT (vehicle kilometers travelled) in congested areas will be necessary. In addition to this, improving vehicie inspection Program should be enforced. 2. As to small-gasoline bus, traffic adaptive control system will be necessary. 3. As to small-diesel bus, non-adjustable engine parameters will have to be applied. .4. As to heal bus and heart truck, catalytic trap oxidizer and limiting VKT in congested areas will do necessary. 5. As to motorcycle, 2-cycle motorcycles should be converted to 4-cycle motorcycles.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2004년도 추계학술대회 및 정기총회
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• pp.289-303
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• 2004

As needs for telecommunications services diversify, an increasingly wide range of telecommunications services is becoming available in the market. Any subscriber can find a service to satisfy his/her telecommunication requirements and competition between providers to retain heavy users is increasing. Service price reductions are one retention strategy, although price reductions for one service can affect the individual-level usage for other services. Price reductions can also be imposed on a service provider by regulation. For these reasons, understanding how price reductions affect service usage is of growing importance to the telecommunications industry for purposes of pricing and tariff development. In this paper, we develop an individual-level usage model for telecommunications services and analyze the effects on usage of a price reduction. We apply the model to age-stratified aggregate traffic data for a Korean mobile telecommunication service provider. Finally, we develop a model to support a market segmentation and price reduction strategy.

• 한국정보기술학회 영문논문지
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• 제10권1호
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• pp.1-14
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• 2020

Antenna selection is a method to enhance the performance of spatial multiplexing multiple-input multiple-output (MIMO) systems, which can achieve the diversity order of the full MIMO systems. Although various selection criteria have been studied in the literature, they should be adjusted to the detection operation implemented at the receiver. In this paper, antenna selection methods that optimize the post-processing signal-to-noise ratio (SNR) and eigenvalue are considered for the lattice reduction (LR)-based receiver. To develop a complexity-efficient antenna selection algorithm, the incremental selection strategy is adopted. Moreover, for improvement of performance, an additional iterative selection method is presented in combination with an incremental strategy.

• 경영과정보연구
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• 제34권1호
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• pp.211-225
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• 2015

본 연구의 목적은 부실기업에서 회생과정을 거쳐 정상기업으로 전환된 회생기업을 대상으로 기업부실 원인과 기업이 선택하는 회생전략 사이의 관련성을 확인하고, 기업이 추구하는 회생전략에 따라 회생성과가 어떻게 달라지는지를 확인하는 데 있다. 국내 상장된 제조기업 중 2000년부터 2012년까지 법원에 법정관리 및 화의신청을 한 기업과 워크아웃 기업중 기업회생에 성공한 113개 기업을 대상으로 설문조사를 실시하였고 회수된 55개 설문과 공시자료를 바탕으로 다중회귀모형에 의해 실증 분석한 결과를 요약하면 다음과 같다. 먼저, 내부부실원인은 자산감축과 비용절감, 즉 효율성제고전략에 긍정적인 영향을 미치는 것으로 나타났고, 반대로 외부부실원인은 수익창출전략(제품/서비스감축, 제품/서비스확대)에 긍정적인 영향을 미치는 것으로 나타났다. 다음으로, 기업이 추구하는 회생전략에 따라 회생성과가 달라지는 지를 실증 분석한 결과, 효율성제고전략(자산감축과 비용절감)은 부채비율감소에 긍정적인 영향을 미치고, 반대로 수익창출전략(제품/서비스감축과 제품/서비스확대)은 매출액증가율에 긍정적인 영향을 미치는 것으로 나타났다. 본 연구는 기존의 부실원인과 회생전략, 회생전략이 회생성과에 미치는 포괄적 분석모형을 넘어 회생원인에 따라 기업이 보다 주안점을 두는 회생전략이 어떻게 달라지며, 회생전략에 따라 회생성과도 달라질 수 있음을 실증적으로 규명해 보았다는데 연구의 의의를 찾을 수 있다.

• 대한조선학회논문집
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• 제60권6호
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• pp.397-405
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• 2023

As interest in greenhouse gas reduction has increased in all sectors, the discussion of the International Maritime Organization (IMO) to regulate pollution by ships is attracting attention in international shipping. At the 80th IMO MEPC held in July 2023, the 「2023 IMO Strategy for the Reduction of Green House Gases from Ships (MEPC. 377(80))」 was adopted, which included the net-zero target around 2050, and a firm intention to the decarbonization of the international shipping sector showed. In particular, energy, fuel and technology targets for zero or near-zero greenhouse gas emissions by 2030 were added as new targets, and total greenhouse gas emission checkpoints for 2030 and 2040 were added as an indicator for achieving the 2050 target. The IMO's goal setting for 2030, which is about seven years away, will impose a lot of technical, economic, and political burden despite the decarbonization technology of international shipping, which has grown to a significant level in a short period of time. Accordingly, this paper presents the comprehensive impact of the 2023 IMO GHG Strategy on international shipping.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.13-18
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• 2023

A subway station is a prominent multi-purpose facility where the quantitative management of fine dust, generated by various factors, is conducted. Recently, eco-friendly air purification methods using air-purifying plants are being discussed, with the focus on biofiltration through vegetation. Previous research in this field has confirmed the reduction effects of transition metals such as Fe, which have been identified as harmful to human health. This study aimed to identify the sources of fine dust dispersion within subway stations and derive an efficient operational strategy for air-purifying plants that takes into account the behavior characteristics of fine dust within multi-purpose facilities. The experiment monitored regional fine dust levels through IAQ stations established based on prior research. Also, the data was analyzed through time-series and correlation analyses by linking it with passenger counts at subway stations and the frequency of train stops. Furthermore, to consider energy efficiency, we conducted component-specific power consumption monitoring. Through this study, we were able to derive the optimal operational strategy for air-purifying plants based on time-series comprehensive analysis data and confirm significant energy efficiency.

• 방사선산업학회지
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• 제17권4호
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• pp.451-456
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• 2023

The subject of this research is what is the most effective strategy of the nuclear sharing strategy of South Korea through the nuclear strategy that the U.S. is pursuing now. The U.S. Nuclear Strategy-related change can be found in a Nuclear Posture Review (NPR) report released by the U.S. The first NPR was announced in 1994 and after that, the U.S. has additionally announced a total of four NPRs along with administration changes. The change in the U.S. nuclear strategy and nuclear power are considered both deterrence and offset strategies. It can be summarized in two ways. First, by maintaining overwhelming nuclear power against the enemy, the U.S. is to lead nuclear advantage that is the core of the U.S. nuclear strategy. Second, the U.S. is to limit the competition of nuclear power with nations seeking to challenge the U.S. nuclear power advantage. Additionally, the U.S. is to actively sign an agreement with nations on the reduction and restriction of nuclear weapons. Through the NPR of the U.S., South Korea should know its unclear power and strategy and have an effective nuclear strategy of South Korea. Therefore, this research is to deal with the suitability of the nuclear sharing strategy with the U.S., which is one of the various nuclear strategies of South Korea.