• 호남수학학술지
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• 제35권4호
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• pp.757-764
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• 2013

In this paper, we give sufficient conditions for a map with nonconvex values to have a continuous selection and the selection extension property in LC-metric spaces under the one-point extension property. And we apply it to weakly lower semicontinuous maps and generalize previous results. We also get a continuous selection theorem for almost lower semicontinuous maps with closed sub-admissible values in $\mathbb{R}$-trees.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1527-1535
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• 2012

Selection of the most informative molecular descriptors from the original data set is a key step for development of quantitative structure activity/property relationship models. Recently, mutual information (MI) has gained increasing attention in feature selection problems. This paper presents an effective mutual information-based feature selection approach, named mutual information maximization by replacing collinear variables (MIMRCV), for nonlinear quantitative structure-property relationship models. The proposed variable selection method was applied to three different QSPR datasets, soil degradation half-life of 47 organophosphorus pesticides, GC-MS retention times of 85 volatile organic compounds, and water-to-micellar cetyltrimethylammonium bromide partition coefficients of 62 organic compounds.The obtained results revealed that using MIMRCV as feature selection method improves the predictive quality of the developed models compared to conventional MI based variable selection algorithms.

• 대한영양사협회학술지
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• 제25권3호
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• pp.188-198
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• 2019

This study examined the subjective health recognition, motivation, selection property, consumption realties, and generalities of elderly people eating out. The ratio of women eating out in those over 60 years of ages was high and people in that age group ate out most actively. The score of convenience-oriented, gourmet-oriented, and dignity-oriented of the selection property for eating out increased with increasing frequency and expenditure for eating out. With increasing age, a negative (-) relationship with a decrease in the safety-oriented score of the selection property for eating out was predicted. As the number of days eating out increased, a positive (+) relationship with an increase in the safety-oriented score of the selection property for eating out was observed. As the scores of physical and social health perception increased, a positive (+) relationship with an increase in the gourmet oriented score was observed. Based on the results, various research on the relationship between the health recognition and eating out behavior of those over 60 years of age are required.

• Communications for Statistical Applications and Methods
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• 제24권6호
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• pp.673-683
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• 2017

The least absolute shrinkage and selection operator (LASSO) has been a popular regression estimator with simultaneous variable selection. However, LASSO does not have the oracle property and its robust version is needed in the case of heavy-tailed errors or serious outliers. We propose a robust penalized regression estimator which provide a simultaneous variable selection and estimator. It is based on the rank regression and the non-convex penalty function, the smoothly clipped absolute deviation (SCAD) function which has the oracle property. The proposed method combines the robustness of the rank regression and the oracle property of the SCAD penalty. We develop an efficient algorithm to compute the proposed estimator that includes a SCAD estimate based on the local linear approximation and the tuning parameter of the penalty function. Our estimate can be obtained by the least absolute deviation method. We used an optimal tuning parameter based on the Bayesian information criterion and the cross validation method. Numerical simulation shows that the proposed estimator is robust and effective to analyze contaminated data.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.108-110
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• 2015

본 논문은 Delay Tolerant Networks(DTN)에서 이동노드의 속도, 방향과 같은 속성정보를 활용하여 이동노드의 상황에 따른 최적의 중계노드를 선정하는 기법을 제안한다. 중계노드의 이동성에 의하여 데이터 패킷을 전달함으로써 목적노드와 상이한 이동성의 중계노드가 선정되면, 전송 지연시간 및 패킷 손실이 자주 발생하였다. 따라서 본 논문에서는 전송 지연시간 및 패킷 손실이 증가하는 문제를 극복하기 위해, 이동노드의 속성정보를 활용하여 중계노드를 선정하는 기법을 제안한다. 제안하는 알고리즘은 서로 다른 이동노드가 접근하면 서로의 속도, 방향과 같은 속성정보를 교환한다. 또한 이동노드의 속성정보를 통해 각 이동노드의 상황을 인지하고 분석함으로써 목적노드에게 효율적으로 데이터를 전달 할 수 있는 중계노드를 선정하게 된다. 주어진 모의 실험결과 이동 노드의 속성정보를 활용하여 중계노드를 선정함으로써 패킷 전송률 측면에서 기존의 연구결과보다 향상된 결과를 보여주었다.

• 경영과정보연구
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• 제33권5호
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• pp.97-115
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• 2014

최근 한국과 중국의 대형마트시장의 경쟁이 치열해지면서 고객만족을 충족시키기 위해 점포속성, 제품속성, 서비스속성, 물리적 환경요인에 관한 연구가 이루어지고 있다. 이에 본 연구에서 한국과 중국 대형마트 구매자의 점포선택요인을 알아보고, 점포에 대한 고객만족과 재방문의도와의 영향관계를 분석하는 것을 목적으로 연구모형을 설계하였다. 또한 점포에 대한 중국과 한국의 고객만족과 재방문의도에 영향을 미치는 관계차이에 대해서도 알아보았다. 이에 따른 개념적 이해와 기존연구의 검토를 통해 가설을 설정하고 관련성 검증을 실시하였다. 실증분석을 위한 자료의 수집은 한국내 대형마트를 이용한 한국 소비자들과 중국내 대형마트를 이용한 중국인 소비자들 대상으로 자료를 수집하였으며 설정된 연구가설에 대해 구조방정식모형 분석을 통해 검증하였다.

• 한국주거학회논문집
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• 제19권3호
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• pp.31-38
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• 2008

Recently, Seoul residential real estate market showed a big change, especially in 2007. The residential property price in Seoul had been mainly affected by 5 provideces: Kangnam-gu, Seocho-gu, Songpa-gu, Gangdong-gu and Yangchun-gu, but these providences started to show the decrease in price while the other providences ironically showed the opposite direction. Therefore, this project was derived from this phenomenon recognition and the necessity as the new market trend requires. The pre-research was carried out with the point of social-population academic view, but this project provides the analysis on the new market trend by simplifying the complex valuation indexes, originated from the pre-research. In result, the aspects of the change could be categorized into time-manner classification and territorial-manner classification, in cope with the change in the satisfaction degree on the residential environment and the selection tendency of the residential property. Based on the the moving-preferred area criteria, the territorial classification was categorized into 3 areas: 5 providences, which showed the initial decrease in real estate price (area 1), the other Kangnam area (area 2), and Kangbuk area (area 3). The result illustrated the reasonable change in the satisfaction degree on the residential environment and the selection tendency of the residential property. This project was able to reach the following conclusion : Firstly, the housing development planning should be devised by the residential environment, including the view and the natural environment, not by the area. Secondly, the housing development planning in the other Kangnam area (area 2) and Kangbuk area (area 3) should embrace the business function, not the housing development only. Last, the housing development planning in Kangbuk area (area 3) should be able to enhance education and culture function and be connected by various transportation system. This project analyzes the change in the satisfaction degree on the residential environment and the selection tendency of the residential property. Thereafter, this project has the purpose of providing the aid in understanding of the basis of housing development information.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.25-29
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• 2003

LQ actuator selection problem for multi-input system discussed in this paper is to determine optimal actuator out of many actuators and input sequences so as to minimize the quadratic control performance. The solution of this problem depends on initial values and has a combinatorial property, so it is extremely difficult to get an optimal solution. For this difficulty, we proposed the concept of comparability of actuators and showed the uniqueness of the solution[1] . Further, to get general optimal solution for LQ problem with actuator selection strategies, we derived the equivalent condition for the comparability of actuator in single-input system . In this paper we extend this result to the case of multi-input system. The derived sufficient condition is applicable in the case of positive semi-definite comparability matrices.

• Journal of Communications and Networks
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• 제12권4호
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• pp.289-307
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• 2010

The problem of model selection arises in a number of contexts, such as subset selection in linear regression, estimation of structures in graphical models, and signal denoising. This paper studies non-asymptotic model selection for the general case of arbitrary (random or deterministic) design matrices and arbitrary nonzero entries of the signal. In this regard, it generalizes the notion of incoherence in the existing literature on model selection and introduces two fundamental measures of coherence-termed as the worst-case coherence and the average coherence-among the columns of a design matrix. It utilizes these two measures of coherence to provide an in-depth analysis of a simple, model-order agnostic one-step thresholding (OST) algorithm for model selection and proves that OST is feasible for exact as well as partial model selection as long as the design matrix obeys an easily verifiable property, which is termed as the coherence property. One of the key insights offered by the ensuing analysis in this regard is that OST can successfully carry out model selection even when methods based on convex optimization such as the lasso fail due to the rank deficiency of the submatrices of the design matrix. In addition, the paper establishes that if the design matrix has reasonably small worst-case and average coherence then OST performs near-optimally when either (i) the energy of any nonzero entry of the signal is close to the average signal energy per nonzero entry or (ii) the signal-to-noise ratio in the measurement system is not too high. Finally, two other key contributions of the paper are that (i) it provides bounds on the average coherence of Gaussian matrices and Gabor frames, and (ii) it extends the results on model selection using OST to low-complexity, model-order agnostic recovery of sparse signals with arbitrary nonzero entries. In particular, this part of the analysis in the paper implies that an Alltop Gabor frame together with OST can successfully carry out model selection and recovery of sparse signals irrespective of the phases of the nonzero entries even if the number of nonzero entries scales almost linearly with the number of rows of the Alltop Gabor frame.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.94-98
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• 2009

In this paper, we propose a new channel estimation scheme for amplify and forward cooperative diversity with relay selection. In order to select best relay, it is necessary to know channel state information (CSI) at the destination. Most of the previous works, however, assume that perfect CSI is available at the destination. In addition, when the number of relay is increased it is difficult to estimate CSI through all relays within coherence time of a channel because of the large amount of frame overhead for channel estimation. In a proposed channel estimation scheme, each terminal has distinct pilot signal which is orthogonal each other. By using orthogonal property of pilot signals, CSI is estimated over two pilot signal transmission phases so that frame overhead is reduced significantly. Due to the orthogonal property among pilot signals, estimation error does not depend on the number of relays. Simulation result shows that the proposed channel estimation scheme provides accurate CSI at the destination.