• 제목/요약/키워드: variance structure

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Genetic risk factors associated with respiratory distress syndrome

  • Jo, Heui Seung
    • Clinical and Experimental Pediatrics
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    • 제57권4호
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    • pp.157-163
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    • 2014
  • Respiratory distress syndrome (RDS) among preterm infants is typically due to a quantitative deficiency of pulmonary surfactant. Aside from the degree of prematurity, diverse environmental and genetic factors can affect the development of RDS. The variance of the risk of RDS in various races/ethnicities or monozygotic/dizygotic twins has suggested genetic influences on this disorder. So far, several specific mutations in genes encoding surfactant-associated molecules have confirmed this. Specific genetic variants contributing to the regulation of pulmonary development, its structure and function, or the inflammatory response could be candidate risk factors for the development of RDS. This review summarizes the background that suggests the genetic predisposition of RDS, the identified mutations, and candidate genetic polymorphisms of pulmonary surfactant proteins associated with RDS.

The Selection of Growth Models in Technological Forecasting

  • Oh, Hyun-Seung
    • 한국경영과학회지
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    • 제16권1호
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    • pp.120-134
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    • 1991
  • Various technological forecasting models have been proposed to represent the time pattern of technological growths. Of six such models studied, some models do significantly better than others, especially at low penetration levels, in predicting future levels of growth. Criteria for selecting an appropriate model for technological growth model are examined in this study. Two major characteristics were selected which differentiate the various models ; the skew of the curve and the underlying assumptions regarding the variance of the error structure of the model. Although the use of statistical techniques stil requires some subjective input and interpretations, this study provides some practical procedures in the selection of technological growth models and helps to reduce or control the potential source of judgmental error inconsistencies in the analyst's decision.

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W-CDMA용 Systolic 어레이 구조를 갖는 상향링크 빔형성기법 성능 분석 (Performance Analysis of Uplink Beamforming using Systolic Array Structure in W-CDMA Systems)

  • 이호중;서상우;이원철
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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    • pp.25-28
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    • 2002
  • 본 논문에서는 W-CDMA(Wide-Code Division Mul-tiple Access)용 Systolic 어레이 구조를 잣는 상향링크 빔형성기법에 대한 성능 분석을 하였다. 적응 어레이 안테나와 Systolic 구조의 MVDR(Minimum Variance Distortionless Response) 알고리즘을 사용하여 구해진 가중치 벡터를 이용하여 원하는 사용자의 방향으로 빔을 형성하고 원하지 않는 사용자의 방향으로는 null을 형성하는 공간필터를 적용하여 W-CDMA 상향링크에서 다중 경로 페이딩과 다중 접속 간섭의 증가에 따른 수신 성능을 분석하였다. 그리고, 안테나 시스템에서 사용되는 가중벡터를 갱신하기 위해 Systolic 구조의 MVDR과 역방향 파일럿 채널을 이용하는 QR-RLS(QR-Recursive Least Squares) 알고리즘을 적용하였다. 본 논문에서는 빔 형성기에 사용하기 위한 역행렬의 계산과 정에 Systolic 어레이 구조를 적용하여 병렬적인 고속처리가 가능한 방법과 효율적인 계산과정을 위해 MVDR 과 QR-RLS 알고리즘을 적용한 공간 필터링의 성능을 소개한다.

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Shape Feature Extraction technique for Content-Based Image Retrieval in Multimedia Databases

  • Kim, Byung-Gon;Han, Joung-Woon;Lee, Jaeho;Haechull Lim
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2000년도 ITC-CSCC -2
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    • pp.869-872
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    • 2000
  • Although many content-based image retrieval systems using shape feature have tried to cover rotation-, position- and scale-invariance between images, there have been problems to cover three kinds of variance at the same time. In this paper, we introduce new approach to extract shape feature from image using MBR(Minimum Bounding Rectangle). The proposed method scans image for extracting MBR information and, based on MBR information, compute contour information that consists of 16 points. The extracted information is converted to specific values by normalization and rotation. The proposed method can cover three kinds of invariance at the same time. We implemented our method and carried out experiments. We constructed R*_tree indexing structure, perform k-nearest neighbor search from query image, and demonstrate the capability and usefulness of our method.

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A Two-Stage Elimination Type Selection Procedure for Stochastically Increasing Distributions : with an Application to Scale Parameters Problem

  • Lee, Seung-Ho
    • Journal of the Korean Statistical Society
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    • 제19권1호
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    • pp.24-44
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    • 1990
  • The purpose of this paper is to extend the idea of Tamhane and Bechhofer (1977, 1979) concerning the normal means problem to some general class of distributions. The key idea in Tamhane and Bechhofer is the derivation of the computable lower bounds on the probability of a correct selection. To derive such lower bounds, they used the specific covariance structure of a multivariate normal distribution. It is shown that such lower bounds can be obtained for a class of stochastically increasing distributions under certain conditions, which is sufficiently general so as to include the normal means problem as a special application. As an application of the general theory to the scale parameters problem, a two-stage elimination type procedure for selecting the population associated with the smallest variance from among several normal populations is proposed. The design constants are tabulated and the relative efficiencies are computed.

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의복디자인의 평가도구 개발을 위한 연구 -실루엣 평가를 중심으로- (A Study on the Development of a Clothing Design Evaluation Instrument)

  • 이경희
    • 대한가정학회지
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    • 제29권1호
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    • pp.37-49
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    • 1991
  • The purpose of this study was to investigate the visual effects of clothing design. The specific objectives were: 1) to develop a clothing design evaluation instrument using semantic differential scales for the purpose of measuring visual responses with clothing design: 2) to identify the factor structure of the clothing design evaluation instrument: 3) to test the differences of perception to the clothing design depending on sex and knowledge about clothing design. The major findings were: 1. 37 pairs of descriptors of clothing form were found to include five factor dimensions (total variance:62.1%). Five major factors were found: attractiveness, practicability, elegance, comfort, hardness and softness. 2. for the visual evaluation of silhouettes, there were significant differences. H-line was explained by the simple image. A-line was explained by the comfortable image. V-line was explained by the mature and refined image. X-line was explained by the attractive and femine image and evaluated positively. 3. For the visual evaluation of observers, there were partly significant differences depending on sex and knowledge about clothing design in the observers' responses. But there were greater differences depending on sex than knowledge about clothing design in the observers' responses.

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Multivariate Poisson Distribution Generated via Reduction from Independent Poisson Variates

  • Kim, Dae-Hak;Jeong, Heong-Chul
    • Journal of the Korean Data and Information Science Society
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    • 제17권3호
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    • pp.953-961
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    • 2006
  • Let's say that we are given a k number of random variables following Poisson distribution that are individually dependent and which forms multivariate Poisson distribution. We particularly dealt with a method of creating random numbers that satisfies the covariance matrix, where the elements of covariance matrix are parameters forming a multivariate Poisson distribution. To create such random numbers, we propose a new algorithm based on the method reducing the number of parameter set and deal with its relationship to the Park et al.(1996) algorithm used in creating multivariate Bernoulli random numbers.

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교란 대기를 통한 스펙클 전파의 통계적 코바리언스 함수의 효과 (Effect of the covariance function on the statistics of speckle propagation through the turbulent atmosphere.)

  • 성평식;박계원
    • 한국정보통신학회논문지
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    • 제3권1호
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    • pp.29-34
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    • 1999
  • 본 논문은 확장된 Huygens-Fresnel원리를 이용하여 섭동대기 공간을 통하여 진행하는 스팩클 전파에서 수신된 강도를 통계적으로 해석하였다. 그 결과 이러한 수식들은 파구조 함수뿐만 아니라 log-amplitude 코바리안스를 포함하고, 정규화 바리언스가 섭동세기에 의존하여 1 이상이 되는 것을 알았다.

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선택적 계수 갱신 알고리즘을 이용한 광대역 부밴드 적응 GSC (Subbnad Adaptive GSC Using the Selective Coefficient Update Algorithm)

  • 김재윤;이창수;유경렬
    • 대한전기학회논문지:시스템및제어부문D
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    • 제53권6호
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    • pp.446-452
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    • 2004
  • Under the condition of a common narrowband target signal and interference signals from several directions, the linearly constrained minimum variance (LCMV) method using the generalized sidelobe canceller (GSC) for adaptive beamforming has been exploited successfully However, in the case of wideband signals, the length of the adaptive filter must be extended. As a result, the complexity of the beamformer increases, which makes real-time implementation difficult. In this paper, we improve the convergence characteristics of the adaptive filter using the transform domain normalized least mean square (NLMS) approach based on the subband GSC structure without the increase of complexity. Besides, the M-MAX algorithm, which is one of various selective coefficient updating methods, is employed in order to remarkably reduce the computational cost without decreasing the convergence quality. With the combination of these methods, we propose a computationally efficient wideband adaptive beamformer and verify its efficiency through a series of simulations.

현대패션에 대한 감성과 감정의 관계 연구(제1보) (A Study of the relationship between Fashion Sensibility and Emotion(Part II))

  • 김유진;이경희
    • 한국의류학회지
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    • 제27권3_4호
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    • pp.418-428
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    • 2003
  • The purpose of this study was to provide the guidance in more objective and proper clothing design reflecting today's consumers' modes in value consumption by identifying the meaning structure and relationship between fashion sensibility and emotion. The stimulus was 54 photos of contemporary costume which represented the Izard' DES. The questionnaire consisted of hi-polar 25 pairs adjective scale of fashion sensibility and the 18 noun scale of emotion was distributed to 970 male and female living in Pusan area. The data were analyzed by Factor analysis, Correlation analysis and Regression analysis using the statistical SPSS package. The major finding of this research were as follows.1. Fashion sensibilities consist of estheticism, maturity, character and feminity to represent 57.17% total varlarlce. 2. Emotions consist of negative emotion, distress afraid, arousal, shame and enjoyment to represent 70.84% total variance. 3. For the relation between fashion sensibility and emotion, they showed significant relationship in most of factors.