• 무역학회지
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• 제46권5호
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• pp.83-98
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• 2021

This study aims to examine the effects of international trade in intermediate input on the implications of international business cycle properties in Korea. To do this, I have extended standard one goods New Keynesian international business cycle model to incorporate the role of intermediate inputs. After constructing the DSGE model, I have analysed the impulse response function and varian decomposition results. The results show that the model could introduce a new channel, that is, "cost channel" like Eyquem and Kamber (2014). In other words, the model has changed the dynamics of aggregate inflation by the cost channel. When the trade in intermediate goods increase, which is measured by openness of foreign input, the volatility of output, consumption and inflation increase two or three times. However, the model itself fails to explain the full account of cycle behavior of historical data, but the results imply that the trade in intermediate input assumption can help to improve the forecasting ability of international business cycle models.

• 자원ㆍ환경경제연구
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• 제15권1호
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• pp.27-50
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• 2006

우리나라 산업의 1990년과 2000년의 $CO_2$ 배출량을 각각 추정하고, 이 기간중 배출량 변화에 영향을 준 요인별 기여도를 조사하였다. 산업별 배출량에는 생산과정에서 직접 사용하는 에너지는 물론 원재료 생산에 사용된 에너지로 인해 간접적으로 배출되는 $CO_2$까지 포함하였다. 배출량 추정에는 통상적인 산업연관모형을 환경부문으로 확장한 $CO_2$ 혼합 산업연관모형을 이용하였다. 배출량 변화의 요인 분해에는 산업연관분석을 이용한 구조분해기법 (IO-SDA)을 사용하였다. 이 때 각 요인별 영향 계산에 적용하는 가중치는 기준연도와 비교연도의 평균값을 사용하여 가중치 선택의 자의성을 줄이고 완전분해가 되게 하였다. 추정 결과 국내 산업의 직 간접 $CO_2$ 배출량은 1990년에 6,444만 탄소톤에서 2000년에는 1억 1,552만 탄소톤으로 5,163만 탄소톤이 증가한 것으로 나타났다. 직접 $CO_2$ 유발계수 변화, 간접 $CO_2$ 유발계수 변화, 국내 최종수요 성장, 수출 증가, 수입 증가, 국내 최종수요 구조 변화, 수입 구조 변화, 수출 구조 변화 등 여덟 가지 요인별로 배출량 변화에 미친 영향을 분석한 결과 직접 $CO_2$ 유발계수 변화, 간접 $CO_2$ 유발계수 변화, 수입수요의 증가 및 구조 변화는 배출량 감소 효과를 낳았으나, 국내 최종수요 성장 및 구조 변화와 수출수요 증가와 구조 변화는 배출량을 증가시키는 요인으로 작용하였다. 산업이 직접 사용하는 에너지로 인한 $CO_2$ 배출량은 물론 제품 생산 과정에서 투입된 원재료의 생산에 소요된 에너지로 인한 배출량까지 모두 파악하는 것은 $CO_2$ 배출 저감 정책의 효율성을 높일 수 있는 기초자료로 활용될 수 있을 것으로 생각된다.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2344-2353
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• 2018

A coupled recursive total least squares (CRTLS) algorithm is proposed for parameter estimation of permanent magnet synchronous machines (PMSMs). TLS considers the errors of both input variables and output ones, and thus achieves more accurate estimates than standard least squares method does. The proposed algorithm consists of two recursive total least squares (RTLS) algorithms for the d-axis subsystem and q-axis subsystem respectively. The incremental singular value decomposition (SVD) for the RTLS obtained by an approximate calculation with less computation. The performance of the CRTLS is demonstrated by simulation and experimental results.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2010년도 하계학술대회
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• pp.9-11
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• 2010

Multiple-input multiple-output (MIMO) systems assisted by multi-relays with single antenna are considered. Signal transmission consists of two hops. In the first hop, the source node broadcasts the vector symbols to all relays, then all relays forward the received signals multiplied by each power gain to the destination simultaneously. Unlike the case of full cooperation between relays such as single relay with multiple antennas, in our case there is no closed form solution for optimal relay power gain with respect to minimum mean square error (MMSE). Thus we propose an alternative approach in which we use an approximation of the cost function based on rank-one matrix decomposition. As a cost function, we choose the trace of MSE matrix. We give several simulation results to validate that our proposed method obtains a negligible performance loss compared to optimal solution obtained by exhaustive search.

• 자원ㆍ환경경제연구
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• 제12권1호
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• pp.91-120
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• 2003

This paper is intended to measure sectoral sustainabilities and inter-industry linkage effects of natural capital depletion of the Korean industries, and to analyze sources of their change over time using the familiar input-output model. The sustainability indicator that we are measuring in this paper is based on the so-called genuine saving concept proposed by the World Bank(1997). We accommodated the concept in the extended analytical framework of Proops et al.(1999) to analyze sectoral sustainabilities of the Korean industries. We decomposed sectoral sustainabilities so measured into their composing factors based on the decomposition method devised by Chung & Rhee (2001). According to our analysis, overall sustainability of the Korean industries has been declined since 1995. In heavy and chemical, transportation, and electricity sectors, their sustainabilities has been gotten worse. Among four major factors influencing the sustainability, change in GDP was the most important followed by changes in savings, industrial structures, and demand patterns.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.245-250
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• 1992

In this paper, we present a nev algorithm for the fast computation of the discrete cosine transform(DCT). This algorithm consists of the three dimensional prime factor-decomposed algorithm(PFA) and three dimensional common factor-decomposed algorithm(CFA). We can compute N-point DCT for the number N decomposable Into three relative prime numbers using PFA and into three common numbers using CFA. We also show input and output index mapping for the three decomposition. it results in requiring fever multiplicaions than the previous algorithms. Particularly, for the large number N, it is more powerful in reducing the number of multiplication.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.695-700
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• 2008

Artificial neural network (ANN) has been extensively used in areas of nonlinear system modeling, analysis and design applications. Basically, ANN has its distinct capabilities of implementing system identification and/or function approximation using a number of input/output patterns that can be obtained via numerical and/or experimental manners. The paper describes a role of ANN, especially a back-propagation neural network (BPN) in the context of engineering analysis, design and optimization. Fundamental mechanism of BPN is briefly summarized in terms of training procedure and function approximation. The BPN based causality analysis (CA) is further discussed to realize the problem decomposition in the context of multidisciplinary design optimization. Such CA is also applied to quantitatively evaluate the uncoupled or decoupled design matrix in the context of axiomatic design with the independence axiom.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권3호
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• pp.1156-1173
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• 2021

In this paper, we propose a new joint precoder and postcoder design strategy to support multiple streams per user in multiuser multiple-input multiple-output (MIMO) systems. We propose two step precoding strategies using equal channel gain decomposition and block diagonalization at the transmitter. With the proposed precoder, the multiuser MIMO channel can be decomposed into multiple parallel channels with equal channel gain per user. After applying receive postcoder which is generated and sent by the transmitter, we can use ML based decoder per stream to achieve full receive diversity. Achievable sum rate bound and diversity performance of the proposed algorithm are presented with feedback signaling design and quantitative complexity analysis. Simulation results show that the proposed algorithm asymptotically approaches to the sum rate capacity of the MIMO broadcast channel while maintaining full diversity order.

• East Asian Economic Review
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• 제28권1호
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• pp.37-67
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• 2024

This paper analyses carbon emissions and value-added embodied in trade between two large developed countries, South Korea and the United States, during 2000-2014. Using multi-regional input-output (MRIO) tables, our analysis reveals that carbon emissions and value-added embodied in exports grew by 19% and 101% for South Korea but shrank by 43% and 7% for the United States. As a result, South Korea experienced a 40% increase in net carbon exports and 243% increase in net value-added exports. At the industry level, the primary drivers of changes in carbon exports were electricity and basic materials. The majority of industries in witnessed improvements in carbon intensities suggesting improved environmental efficiency. While both countries achieved a decoupling of carbon emissions from value-added exports, substantial year-to-year and sectoral variations were observed. Finally, structural decomposition analysis indicates that domestic supply-side factors played a role in decreasing emissions whereas foreign demand-side factors contributed to emissions increases. In line with the main findings, various implications for policy and future research are discussed.

• 한국통신학회논문지
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• 제40권6호
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• pp.981-989
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• 2015

최적 ML(Maximum Likelihood) 기법 및 sphere decoding(SD), QRM-MLD(QR decomposition with M-algorithm Maximum Likelihood Detection) 기반의 준 최적 검출 기법을 적용한 MIMO(Multiple-Input Multiple-Output) 시스템에서의 LLR(Log Likelihood Ratio) 계산은 변조 차수 및 송/수신 안테나의 수가 증가할수록 그 복잡도가 지수적으로 증가하여 구현 및 성능 면에서 큰 문제점을 야기한다. 본 논문에서는 고차 변조 방식 기반의 $N_T{\times}N_R$ MIMO시스템 수신기의 QRM-MLD 기반 MIMO 검출기에서 연판정 시 아주 낮은 복잡도로 1dB 이내의 ML 검출 기법에 대한 오류 성능 접근도를 갖는 LLR 계산 방법을 제시하고, 컴퓨터 시뮬레이션을 통해 여러 M 값에 대한 MIMO 시스템의 BER(Bit Error Rate) 결과를 도출하고 분석하여 제시된 방법의 유효성을 검증한다.