• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4967-4986
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• 2015

Multi-hop relaying communications have great potentials in improving transmission performance by deploying relay nodes. The benefit is critically dependent on the accuracy of the channel state information (CSI) of all the transmitting links. However, the CSI has to be estimated. In this paper, we investigate the channel estimation problem in one-way multi-hop MIMO amplify-and-forward (AF) relay system, where both the two-hop and three-hop communication link exist. Traditional point-to-point MIMO channel estimation methods will result in error propagation in estimating relay links, and separately tackling the channel estimation issue of each link will lose the gain as part of channel matrices involved in multiple communication links. In order to exploit all the available gains, we develop a novel channel estimation model by structuring different communication links using the PARAFAC and PARATUCK2 tensor analysis. Furthermore, a two-stage fitting algorithm is derived to estimate all the channel matrices involved in the communication process. In particular, essential uniqueness is further discussed. Simulation results demonstrate the advantage and effectiveness of the proposed channel estimator.

• 한국사회복지학
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• 제57권2호
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• pp.297-320
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• 2005

본 연구는 장애인차별금지법의 제정으로 장애인 차별이 해소될 경우에 대한 잠재적 비용과 편익을 추정함으로써 장애인차별금지법 제정에 도움을 주고자 하는 목적으로 시도되었다. 장애인차별금지법 제정으로 인한 잠재적 편익은 장애인 추가 고용으로 인한 장애인의 소득 증대, 사업주의 고용부담금 감소, 공공부조성 급여의 감소를 중심으로 추정하였으며, 비용은 장애인을 고용함으로써 사업주가 특별히 투자해야 할 비용과 차별시정기구 운영비를 중심으로 추정하였다. 추정 결과 7%의 할인율 하에서 얻게 되는 순현재가치는 12,700,301백만원으로 매우 크게 나타났으며 비용-편익비는 96.8로 역시 매우 크게 나타났다. 할인율을 변화시켜 민감도 분석을 한 결과도 큰 변화가 없었다. 이와 같은 추정 결과 장애인차별금지법이 제정되어 차별이 해소될 경우 사회의 잠재적 순편익은 매우 크다는 것을 알 수 있었다. 결국 장애인차별금지법 제정의 필요성이 강조된다고 할 수 있다.

• KDI Journal of Economic Policy
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• 제36권1호
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• pp.43-80
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• 2014

본고는 조건부가치측정법을 비용편익분석에 이용하기 위하여 공공시설의 신설에 따른 총편익의 산정을 보다 엄밀히 수행하는 방법을 제시한다. 즉, 설문을 통해 가구당 지불의사액을 추정하는 경우, 응답자의 소득 및 응답자의 거주지와 해당 공공시설 사업지 간의 거리가 지불의사액에 영향을 미치는지를 확인하고자 한다. 구조적 효용격차모형을 이용한 사례분석 결과 지불의사액에 대한 소득효과 및 거리-소멸 효과가 존재함을 확인하였으며, 총편익의 산정 시 이들을 고려하지 않는 경우 산정된 총편익의 값이 크게 달라질 수 있음을 보였다. 이에 본고는 조건부가치측정법을 비용편익분석에 이용하는 경우 총편익의 산정에 있어 주의를 기울여야 함을 강조한다. 비용편익분석에 있어 총비용의 추정이 정확히 이루어진다 하더라도 가구당 지불의사액의 추정 및 이들을 합산하여 총편익을 산정하는 방식이 옳지 못할 경우 편익/비용(B/C) 비율이 크게 달라질 수 있기 때문이다. 한편, 효용격차 구조모형을 따르지 않고 임의적으로 유사한 추정을 수행한 결과는 구조모형의 추정치와 매우 큰 차이를 보임을 알 수 있었다. 따라서 총편익의 산정은 구조모형의 설정을 따르는 것이 바람직할 것이다. 마지막으로 시뮬레이션을 통해 모형의 적합성을 검증하였으며, 소득효과와 거리-소멸 효과를 고려하지 않는 경우 지역균형발전의 관점에서 바람직하지 못한 총편익의 추정 결과를 얻음을 밝혔다.

• Communications for Statistical Applications and Methods
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• 제21권3호
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• pp.235-243
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• 2014

Constrained Bayesian estimates overcome the over shrinkness toward the mean which usual Bayes and empirical Bayes estimates produce by matching first and second empirical moments; subsequently, a constrained Bayes estimate is recommended to use in case the research objective is to produce a histogram of the estimates considering the location and dispersion. The well-known squared error loss function exclusively emphasizes the precision of estimation and may lead to biased estimators. Thus, the balanced loss function is suggested to reflect both goodness of fit and precision of estimation. In insurance pricing, the accurate location estimates of risk and also dispersion estimates of each risk group should be considered under proper loss function. In this paper, by applying these two ideas, the benefit of the constrained Bayes estimates and balanced loss function will be discussed; in addition, application effectiveness will be proved through an analysis of real insurance accident data.

• Journal of information and communication convergence engineering
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• 제13권3호
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• pp.152-158
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• 2015

We consider the problem of designing independently operating local quantizers at nodes in distributed estimation systems, where many spatially distributed sensor nodes measure a parameter of interest, quantize these measurements, and send the quantized data to a fusion node, which conducts the parameter estimation. Motivated by the discussion that the estimation accuracy can be improved by using the quantized data with a high probability of occurrence, we propose an iterative algorithm with a simple design rule that produces quantizers by searching boundary values with an increased likelihood. We prove that this design rule generates a considerably reduced interval for finding the next boundary values, yielding a low design complexity. We demonstrate through extensive simulations that the proposed algorithm achieves a significant performance gain with respect to traditional quantizer designs. A comparison with the recently published novel algorithms further illustrates the benefit of the proposed technique in terms of performance and design complexity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3055-3070
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• 2013

This paper proposes an improved carrier frequency offset (CFO) and sampling frequency offset (SFO) estimation scheme for orthogonal frequency division multiplexing (OFDM) based broadcasting system with cyclic delay diversity (CDD) antenna. By exploiting a periodic nature of channel transfer function, cyclic delay and pilot pattern with a maximum channel power are carefully chosen, which helps to enable a robust estimation of CFO and SFO against the frequency selectivity of the channel. As a performance measure, a closed-form expression for the achievable mean square error of the proposed scheme is derived and is verified through simulations using the parameters of the digital radio mondiale standard. The comparison results show that the proposed frequency estimator is shown to benefit from properly selected delay parameter and pilot pattern, with a performance better than the existing estimator.

• 한국농공학회지
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• 제11권3호
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• pp.1742-1748
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• 1969

This is a method to determine the boundary line of reservoir flooding area which will be purchased. Until now, flood water level was used as the boundary line. By lowering this line from flood water level, purchasing cost of reservoir flooding area can be cut down. Sometimes, temporary flooding of arable land outside the boundary occurs. During the life of reservoir, flood damage to crop product on of this land must be indemified with net berefit from arable land between the bovndary line and normal water level. Following is the basic formula to determine the line. (Estimated flood damage to crop production of land outside the boundary line $\leqq$ Estimated net beneift from land between the boundary line and normal water level.) Minimum difference between both sides is needed to minimize the purchasing area. Flood damage and net benefit are estimated by hydrologic estimation with rainfall data and crop production estimation.

• 한국CDE학회논문집
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• 제15권4호
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• pp.261-270
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• 2010

These days, architectural projects are becoming larger and more complex. And lots of information occurs through each phases and areas. For these reason, it is emphasized that collaboration with other parts. Therefore we need more effective architectural design process. However, it is difficult to collaborate in early stage with existing design process and it causes unnecessary spending of time and cost because of 2D-based working system. For solving these problem, we should introduce BIM-based Integrated Design Process which makes it possible to collaborate with other parts from early stage. Now the AEC industry in Korea has been trying to introduce BIM, and promoting variety of related business. However, for actual application of this system, it is unfortunately necessary to change various system throughout the construction industry. And this will cause lots of effort and expense. It is essential that scientific analysis and evaluation of efficiency and validity about this investment, because estimation of the investment and accompanying effects will provide reasonable standard of judgment for investment decision. Thus, this research conducted Cost-Benefit Analysis about BIM-based Integrated Design Process compared to existing design process. It is expected that this paper can be used for preliminary data in the future BIM market.

• Environmental Engineering Research
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• 제24권1호
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• pp.63-73
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• 2019

This study suggests a method for calculating the benefits of water pipe renewal based on an estimate of the water supply suspension risk. The proposed method based on five benefit items is more direct and specific than other benefit estimation methods. In addition, a methodology evaluating the economics of pipe renewal based on pipe failure rate is proposed for estimating the optimal renewal point from an economic perspective. By estimating the optimal renewal period based on a yearly benefit cost ratio per pipe in a case study area, it was possible to draft an optimal renewal plan for the subject region from an economic perspective. Compared with other methodologies, a reasonable optimal renewal period was derived from an economic point of view. The result of this study may be used to develop future water pipe renewal plans. Moreover, the proposed methodologies and results derived from this study can be applied to asset management plans.

• 한국문헌정보학회지
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• 제56권3호
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• pp.265-290
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• 2022

본 연구는 한국과학기술정보연구원의 OA논문 통합서비스플랫폼(Discover)에 대한 비용편익분석을 통해 사업의 경제성 평가를 수행하였다. 학술연구자 1,313명, 바이오산업 연구개발자 49명, 일반 산업체 연구개발자 102명 등 서비스 수혜 집단별로 설문조사를 실시하여 편익측정에 필요한 기초자료를 수집하였다. 시스템 구축과 운영에 소요되는 비용, 직접편익과 간접편익을 추정한 후, 이를 토대로 비용편익분석과 민감도 분석을 실시하였다. 우선 직접 편익에 한정한 비용편익분석 결과, 총 8년간 사업에 투입된 사업투자비용(약 56.3억)의 약 14배인 820억 원의 편익이 발생할 것으로 추정되었다. 직간접편익을 합산한 비용편익분석 결과 역시 BCR이 최소 98.9, NPV는 5,388억 원 등으로 추정되어 사업의 경제적 타당성이 충분히 확보되었다. 본 분석 결과는 국가 차원의 OA논문 통합서비스플랫폼 개발 및 구축의 타당성 확보에 기여할 수 있으며, 본 연구에서 개발된 편익추정모형은 향후 사업 진행 과정에서 평가도구로 활용될 수 있을 것이다.