• 제목/요약/키워드: Coefficient of Variance

검색결과 1,088건 처리시간 0.035초

디지털 PID 제어기의 제한 요소 영향 분석(II):유한 단어 길이 문 (Analysis of Limitation Factor Effects on Digital PID Controller(II) : Finite Wordlength Issue)

  • 홍석민;김인중;이상정
    • 대한전기학회논문지
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    • 제43권2호
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    • pp.318-329
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    • 1994
  • This paper deals with the finite wordlength effect on the performance of digital PID controllers. The finite wordlength, one of the major limitation factors in digital controllers, results on two kinds of quantization error : the signal quantization error and the coefficient quantization error. This paper derives the variance of the plant output due to the signal quantization error. Using stability margins as performance criterion, the statistical wordlength concept is adopted for coefficient wordlength selection. Finally, the experimental results exhibit satisfactory performance of the digital PID controller with statistical coefficient wordlength.

간호정보역량 측정도구의 타당도 및 신뢰도 (Validity and Reliability of Informatics Competencies for Nurses Among Korean Nurses)

  • 김명수
    • 성인간호학회지
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    • 제20권3호
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    • pp.470-480
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    • 2008
  • Purpose: The purpose of this study was to validate the scale of Informatics Competencies for Nurses developed by Staggers, Gassert & Curran(2001) among Korean nurses. Methods: The subjects of this study were 58 RN-BSN students and 314 nurses in Busan, Ulsan and Kyoungnam province. Data were collected by questionnaires from June to August, 2006 and from October, 2006 to August, 2007 and were analyzed by Principal Component Analysis for construct validity and Cronbach's ${\alpha}$ coefficient for reliability. Results: A factor analysis was conducted and 30 items that had a factor loading more than .40 were extracted. The explained variance from 5 factors was 55.33% of the total variance. The factors were named 'basic computer usage', 'medical informatics-related software usage', 'computer related information management', 'perception of informatics', and 'information search using internet'. The first factor consisted 10 items which explained 29.89% of the total variance and the second factor contained 7 items. The Cronbach's ${\alpha}$ coefficient was .91 among the 30 items. Conclusion: This scale, Informatics Competencies for Nurses, was proved as a proper instrument to apply to Korean nurses.

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Nonnegative variance component estimation for mixed-effects models

  • Choi, Jaesung
    • Communications for Statistical Applications and Methods
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    • 제27권5호
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    • pp.523-533
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    • 2020
  • This paper suggests three available methods for finding nonnegative estimates of variance components of the random effects in mixed models. The three proposed methods based on the concepts of projections are called projection method I, II, and III. Each method derives sums of squares uniquely based on its own method of projections. All the sums of squares in quadratic forms are calculated as the squared lengths of projections of an observation vector; therefore, there is discussion on the decomposition of the observation vector into the sum of orthogonal projections for establishing a projection model. The projection model in matrix form is constructed by ascertaining the orthogonal projections defined on vector subspaces. Nonnegative estimates are then obtained by the projection model where all the coefficient matrices of the effects in the model are orthogonal to each other. Each method provides its own system of linear equations in a different way for the estimation of variance components; however, the estimates are given as the same regardless of the methods, whichever is used. Hartley's synthesis is used as a method for finding the coefficients of variance components.

네트워크 트래픽 특성을 이용한 스캐닝 웜 탐지기법 (Detection Algorithm of Scanning worms using network traffic characteristics)

  • 김재현;강신헌
    • 정보보호학회논문지
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    • 제17권1호
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    • pp.57-66
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    • 2007
  • 스캐닝 웜은 네트워크 관리자가 미처 대응하기 전에 넓게 전파되므로 차단하기 힘들고 그 피해가 상당히 크다. 따라서 자동으로 스캐닝 웜의 발생을 탐지하고 이에 대응할 수 있는 방법이 필요하다. 본 논문에서는 스캐닝 웜의 트래픽 특성을 분석하여 정상 트래픽과 이상 트래픽을 구분할 수 있는 탐지 알고리즘을 제안한다. 스캐닝 웜의 탐지를 위해 variance, VMR 및 correlation coefficient를 이용하는 방법을 제안하고, 시뮬레이션을 통해 기존의 방법과 성능을 비교하였다. 그 결과 기존의 방법에 비하여 간단한 계산을 통해 스캐닝 웜의 효율적인 탐지가 가능함을 확인하였다.

Relationships between Distribution of Number of Transferable Embryos and Inbreeding Coefficient in a MOET Dairy Cattle Population

  • Terawaki, Y.;Asada, Y.
    • Asian-Australasian Journal of Animal Sciences
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    • 제15권12호
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    • pp.1686-1689
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    • 2002
  • Genetic gains and inbreeding coefficients in a Holstein MOET breeding population were predicted under different conditions relating to the distribution of the number of transferable embryos collected per flush using Monte Carlo simulation. The numbers of transferable embryos collected per flush were determined using five distributions (distributions 1, 3, 5, 7 and 9) with different aspects and similar means. Distributions 1, 3, 5, 7 and 9 were assumed to have gamma distribution's parameters ($\alpha$ and $\beta$) of (1 and 4.4), (3 and 1.47), (5 and 0.88), (7 and 0.63) and (9 and 0.49), respectively. Inbreeding rates were statistically significantly different among distributions but genetic gains were not. Relationships between inbreeding rates and variances of family size could be were clearly distinguished. The highest inbreeding coefficients were predicted in distribution 1 with the largest variance of family size, while distributions 5, 7 and 9 with smaller variance of family size had lower inbreeding coefficients.

Edutainment식 한자 학습 시스템의 구현 및 성능 평가 - 크론박 알파와 분산분석을 이용한 성능평가 - (Implementation and Performance Evaluation of the Learning System for Chinese Characters in Edutainment - Performance Evaluation using the Cronbach's coefficient alpha and Analysis of variance-)

  • 이은아;김태석
    • 한국시뮬레이션학회논문지
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    • 제14권4호
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    • pp.9-18
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    • 2005
  • In this paper, the system is implemented in four ways , For those who want to learn Chinese characters using the internet, and To make the learning more interesting and entertaining. Four different learning methods have been provided , using the transition process of Chinese characters, games, animations, and an illustration of the relationships between Chinese Characters and korean letters. The subjects of the evaluation were freshmen polled about the Chinese character learning system. The evaluation methods are : the validity of the research content is evaluated using the Cronbach's coefficient alpha and the performance of the system is evaluated by F-type of Analysis of variance.

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서울시 남성의 연령별 체형 분석 (Analysis of Somatotype according to Age on Male Residents in Seoul)

  • 임영문;황영섭
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2008년도 추계학술대회
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    • pp.353-359
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    • 2008
  • Somatotype is a very important factor for the comfortable and safe work environments. Many researches are trying to find the characteristics of somatotype according to age. Thus, the main objective of this study is to analyze somatotype of male residents in Seoul. The data used in this study included 267 men subjects who are living in Seoul. In order to analyze a detailed somatotype of citizens, age groups are divided into six groups. In order to compare and analyze data, Coefficient of Variance, Cronbach's Alpha, $R\ddot{o}hrer$ Index and Drop Value were used in this study. The results of this study can be applied to the comfortable and safe work environments for workers.

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패널요원 수행능력 평가에 사용된 분산분석, 상관분석, 주성분분석 결과의 비교 (Evaluation of Panel Performance by Analysis of Variance, Correlation Analysis and Principal Component Analysis)

  • 김상숙;홍성희;민봉기;신명곤
    • 한국식품과학회지
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    • 제26권1호
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    • pp.57-61
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    • 1994
  • Performance of panelists trained for cooked rice quality was evaluated using analysis of variance, correlation analysis, and principal component analysis. Each method offered different information. Results showed that panleists with high F ratios (p=0.05) did not always have high correlation coefficient (p=0.05) with mean values pooled from whole panel. The results of analysis of variance for the panelists whose performance were extremely good or extremely poor were consistent with those of correlation analysis. Outliers designated by principal component analysis were different from the panelists whose performance was defined as extremely good or extremely poor by analysis of variance and correlation analysis. The results of principal component analysis descriminated the panelists with different scoring range more than different scoring trends depending on the treatments. Our study suggested combination of analysis of variance and correlation analysis provided valid basis for screening panelists.

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Detecting the Influential Observation Using Intrinsic Bayes Factors

  • Chung, Younshik
    • Journal of the Korean Statistical Society
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    • 제29권1호
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    • pp.81-94
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    • 2000
  • For the balanced variance component model, sometimes intraclass correlation coefficient is of interest. If there is little information about the parameter, then the reference prior(Berger and Bernardo, 1992) is widely used. Pettit nd Young(1990) considered a measrue of the effect of a single observation on a logarithmic Bayes factor. However, under such a reference prior, the Bayes factor depends on the ratio of unspecified constants. In order to discard this problem, influence diagnostic measures using the intrinsic Bayes factor(Berger and Pericchi, 1996) is presented. Finally, one simulated dataset is provided which illustrates the methodology with appropriate simulation based computational formulas. In order to overcome the difficult Bayesian computation, MCMC methods, such as Gibbs sampler(Gelfand and Smith, 1990) and Metropolis algorithm, are empolyed.

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최소총계적계수 감도를 갖는 상태공간 디지틀 필터의 합성 (Synthesis of the State-space Digital Filter with Minimum Statistical Cofficient Sensitivity)

  • 문용선;박종안
    • 한국통신학회논문지
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    • 제13권6호
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    • pp.510-520
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    • 1988
  • 無限誤長 상태 공간 디지틀 필터를 有限誤長 상태 공간 디지틀 필터로 실현할 때 量子化 誤差인 상태 공간 계수〔ABCD〕의 미소 변동에 기인한, 출력 오차 分散을 $\Delta$〔ABCD〕의 分散으로 正規化하였다. 즉, S=E을 統計的 感度로 정의하고 시스템 구조적 성질을 나타내는 可制御性 Gramian, 그리고 2차 모드 해석 방법을 상태 공간 디지틀 필터에 확장해서 最小 統計的 感度를 갖는 실현 구조를 합성하였으며 시뮬레이션을 통하여 최소 구조 합성의 유효성을 확인하였다.

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