• 제목/요약/키워드: invariant measure

검색결과 107건 처리시간 0.202초

Psychological Well-being Measurement: A Comparative Study of Korean and American Adults

  • An Jeong-shin;Lambert Michael C.;Han Gyoung-hae;Cha Seung-eun
    • International Journal of Human Ecology
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    • 제5권2호
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    • pp.13-29
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    • 2004
  • Ryff's(1989) psychological well-being measure is used to assess and sometimes compare Korean and American adults, however, there is no information regarding whether its dimensions are psychometrically invariant across, whether its items provide sufficient information for, and whether each item measures identical trait levels in, the two nations. Confirmatory factor analysis on response 1,696 Korean and 3,669 American adults, gave to the measure revealed lack of fit and absence of factorial invariance across the two nations. Item response theory revealed significant variance for items on each factor across two countries that most items yielded limited psychometric information. And that each item measure different trait levels, suggesting that in its present form, the measure might lead to misleading results for, and across the two nations.

A modification of McFadden's R2 for binary and ordinal response models

  • Ejike R. Ugba;Jan Gertheiss
    • Communications for Statistical Applications and Methods
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    • 제30권1호
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    • pp.49-63
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    • 2023
  • A lot of studies on the summary measures of predictive strength of categorical response models consider the likelihood ratio index (LRI), also known as the McFadden-R2, a better option than many other measures. We propose a simple modification of the LRI that adjusts for the effect of the number of response categories on the measure and that also rescales its values, mimicking an underlying latent measure. The modified measure is applicable to both binary and ordinal response models fitted by maximum likelihood. Results from simulation studies and a real data example on the olfactory perception of boar taint show that the proposed measure outperforms most of the widely used goodness-of-fit measures for binary and ordinal models. The proposed R2 interestingly proves quite invariant to an increasing number of response categories of an ordinal model.

위치 이동에 무관한 홍채 인식을 위한 웨이블렛 변환 기술 (Wavelet Transform Technology for Translation-invariant Iris Recognition)

  • 임철수
    • 정보처리학회논문지B
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    • 제10B권4호
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    • pp.459-464
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    • 2003
  • 본 논문에서 제안한 위치 이동에 무관한 웨이블렛 변환을 이용한 홍채 인식 방법은 영상 획득 장비에 의해 획득한 사용자의 눈 영상에 대하여 홍채 영역만을 추출하기 위한 전처리를 수행하고 전처리를 거친 홍채 영상에 의하여 사용자의 신원을 식별하는데 있어서 홍채 영상의 기울어짐 및 이동 문제를 해결하였다. 이를 위해서 일반적인 웨이블렛을 사용하는 대신, 위치 이동에 무관한 웨이블렛 변환을 통하여 최적의 특징값을 추출한후, 이를 코드화하여 저장한 후, 비교하여 본인 여부를 식별하였다. 실험결과 제안된 방법으로 생성된 특징 벡터와 기존에 등록된 특징 벡터의 일치도 측정에 있어서 종래의 웨이블렛 변환 홍채 인식 방법보다 오인식률(FAR) 및 오거부율(FRR)이 현저하게 감소하였다.

직류서보전동기 위치제어기의 성능향상에 관한 연구 (A study on the Performance Improvement of Position Controller in DC Servo Motor System)

  • 유종걸;이기상;홍순찬
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1991년도 하계학술대회 논문집
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    • pp.555-558
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    • 1991
  • The IESF(Integral Error and State Feedback) controller, which incorporates state feedback as a modern control scheme and integral action as a classical control scheme, has better performance than that of the conventional PID controller in linear time-invariant systems. The IESF controller requires the measurement of all the state variables. But, unfortunately, it may be difficult or impossible to measure all state variables in many applications. And the IESF controller is applicable only to pole-assignable linear time-invariant system without time delay. In this paper, new IESF controller structure was proposed which performs feedback with only measurable state variables. In order to estimate the unmeasurable state variables. It was adopted the filter mode by full-order obserber. The good performance and effectiveness of the proposed controller was confirmed by computer simulation.

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이동로봇의 위치 추정을 위한 스케일 불변 특징점 추출 및 거리 측정에 관한 연구 (A Study on Scale-Invariant Features Extraction and Distance Measurement for Localization of Mobile Robot)

  • 정대섭;장문석;유제군;이응혁;심재홍
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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    • pp.625-627
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    • 2005
  • Existent distance measurement that use camera is method that use both Stereo Camera and Monocular Camera, There is shortcoming that method that use Stereo Camera is sensitive in effect of a lot of expenses and environment variables, and method that use Monocular Camera are big computational complexity and error. In this study, reduce expense and error using Monocular Camera and I suggest algorithm that measure distance, Extract features using scale Invariant features Transform(SIFT) for distance measurement, and this measures distance through features matching and geometrical analysis, Proposed method proves measuring distance with wall by geometrical analysis free wall through feature point abstraction and matching.

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CHARACTERIZING FUNCTIONS FIXED BY A WEIGHTED BEREZIN TRANSFORM IN THE BIDISC

  • Lee, Jaesung
    • Korean Journal of Mathematics
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    • 제27권2호
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    • pp.437-444
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    • 2019
  • For c > -1, let ${\nu}_c$ denote a weighted radial measure on ${\mathbb{C}}$ normalized so that ${\nu}_c(D)=1$. For $c_1,c_2>-1$ and $f{\in}L^1(D^2,\;{\nu}_{c_1}{\times}{\nu}_{c_2})$, we define the weighted Berezin transform $B_{c_1,c_2}f$ on $D^2$ by $$(B_{c_1,c_2})f(z,w)={\displaystyle{\smashmargin2{\int\nolimits_D}{\int\nolimits_D}}}f({\varphi}_z(x),\;{\varphi}_w(y))\;d{\nu}_{c_1}(x)d{\upsilon}_{c_2}(y)$$. This paper is about the space $M^p_{c_1,c_2}$ of function $f{\in}L^p(D^2,\;{\nu}_{c_1}{\times}{\nu}_{c_2})$ ) satisfying $B_{c_1,c_2}f=f$ for $1{\leq}p<{\infty}$. We find the identity operator on $M^p_{c_1,c_2}$ by using invariant Laplacians and we characterize some special type of functions in $M^p_{c_1,c_2}$.

A NEW LOOK AT THE FUNDAMENTAL THEOREM OF ASSET PRICING

  • Yan, Jia-An
    • 대한수학회지
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    • 제35권3호
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    • pp.659-673
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    • 1998
  • In this paper we consider a security market whose asset price process is a vector semimartingale. The market is said to be fair if there exists an equivalent martingale measure for the price process, deflated by a numeraire asset. It is shown that the fairness of a market is invariant under the change of numeraire. As a consequence, we show that the characterization of the fairness of a market is reduced to the case where the deflated price process is bounded. In the latter case a theorem of Kreps (1981) has already solved the problem. By using a theorem of Delbaen and Schachermayer (1994) we obtain an intrinsic characterization of the fairness of a market, which is more intuitive than Kreps' theorem. It is shown that the arbitrage pricing of replicatable contingent claims is independent of the choice of numeraire and equivalent martingale measure. A sufficient condition for the fairness of a market, modeled by an Ito process, is given.

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Global Feature Extraction and Recognition from Matrices of Gabor Feature Faces

  • Odoyo, Wilfred O.;Cho, Beom-Joon
    • Journal of information and communication convergence engineering
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    • 제9권2호
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    • pp.207-211
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    • 2011
  • This paper presents a method for facial feature representation and recognition from the Covariance Matrices of the Gabor-filtered images. Gabor filters are a very powerful tool for processing images that respond to different local orientations and wave numbers around points of interest, especially on the local features on the face. This is a very unique attribute needed to extract special features around the facial components like eyebrows, eyes, mouth and nose. The Covariance matrices computed on Gabor filtered faces are adopted as the feature representation for face recognition. Geodesic distance measure is used as a matching measure and is preferred for its global consistency over other methods. Geodesic measure takes into consideration the position of the data points in addition to the geometric structure of given face images. The proposed method is invariant and robust under rotation, pose, or boundary distortion. Tests run on random images and also on publicly available JAFFE and FRAV3D face recognition databases provide impressively high percentage of recognition.

CENTRAL LIMIT THEOREM ON CHEBYSHEV POLYNOMIALS

  • Ahn, Young-Ho
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제21권4호
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    • pp.271-279
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    • 2014
  • Let $T_l$ be a transformation on the interval [-1, 1] defined by Chebyshev polynomial of degree $l(l{\geq}2)$, i.e., $T_l(cos{\theta})=cos(l{\theta})$. In this paper, we consider $T_l$ as a measure preserving transformation on [-1, 1] with an invariant measure $\frac{1}{\sqrt[\pi]{1-x^2}}dx$. We show that If f(x) is a nonconstant step function with finite k-discontinuity points with k < l-1, then it satisfies the Central Limit Theorem. We also give an explicit method how to check whether it satisfies the Central Limit Theorem or not in the cases of general step functions with finite discontinuity points.

중학교 3학년 수학교과서 통계단원에 나타난 요약개념 분석 (A summary-concept based analysis on the representative values and the measures of spread with the 9th grade Korean mathematics textbook)

  • 이영하;이은희
    • 한국수학교육학회지시리즈A:수학교육
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    • 제50권4호
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    • pp.489-505
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    • 2011
  • This study is an analysis on the focus of textbooks regarding the statistical chapters of "measures of representative(central tendency) and of the spread". Applying the summary-concept criteria of Juhyeon Nam(2007), 4 kinds of aspect of the chapter; (1) definition and its teleological validity of the measures of representative, (2) definition and practical value of the measures of spread (3) distributional form on the measures of representative and of spread (4) location and scale preservation or invariance of the measures of representative and of spread were observed. On the measures of representative, some definitions were insufficient to check the teleological validity of the measure. Most definitions of the measure of spread were based on the practical view points but no preparation for the future statistical inferences were found even by implication. Some books mention about the measures of representative and of spread for distributions, but we could not find any comments on the correspondence between the sample mean and the expectation of a distribution or population mean. However it is stimulant that some books check the validity of corresponding measures with the location and scale preservation or invariant property, that were not found in the previous curriculum.