• Journal of the Korean Data and Information Science Society
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• 제25권3호
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• pp.547-554
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• 2014

본 논문은 실험자료에 대한 분석모형으로 이원 분산분석모형을 가정한다. 확률효과 모형의 가정하에 분산성분의 추정량을 구하기 위한 방법으로 적률법을 가정하고 있다. 분산성분의 적률 추정방법인 Henderson의 방법 I과 방법 III을 다루고 있다. Henderson의 두 방법에서 소개되는 제곱합 대신에 벡터공간에서의 사영을 활용하는 방법을 제시하고 있다. 또한 제곱합의 기대값 계산을 위해 두 방법 모두 Hartley의 합성법을 제공하고 있으나 본 논문에서는 관련행렬의 고유근을 이용할 수 있음을 제시하고 있다. 분산성분의 해를 얻기 위한 방법의 차이에서 유도되는 연립방정식들은 같지 않으나 양수의 분산성분들에 대한 해는 유사함을 보여주고 있다.

• 한국소음진동공학회논문집
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• 제18권12호
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• pp.1217-1223
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• 2008

Vehicle vibration mostly originates from the road excitation and causes discomfort, fatigue and even injury to a driver. Vehicle ride comfort is one of the most important performance indices to achieve a high-quality vehicle design. Since design parameter variations inevitably result in the vehicle ride comfort variance, the variance characteristics should be analyzed in the early design stage of the vehicle. The vehicle ride comfort is often defined by an index which employs a weighted RMS value of the acceleration PSD of a seat position. The design solution is obtained through two steps in this study. An optimization problem to obtain a minimum ride comfort index is solved first. Then another optimization problem to obtain minimum variance of the ride comfort index is solved. For the optimization problems, the equations of motion and the sensitivity equations are derived basing on a 5-DOF vehicle model. The numerical results show that an optimal solution for the minimum ride comfort is not necessarily same as that of the minimum variance of the ride comfort.

• 생명과학회지
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• 제14권3호
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• pp.400-405
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• 2004

한국내 분포하는 음나무(Kalopanox pictus Nakai)의 집단간 분화를 연구하기 위해 형태적 특성을 조사하였다. 23개 형태 형질에 근거하여 지역간 분화는 현저하였다. 아홉 집단에서 138표본으로 유효한 분류학적 단위(OTU)를 표현형 유사도와 형태적 변이를 조사하였으며 주성분 분석을 실시하였다. 첫 세 주성분 요소가 전체 변이의 77.0%에 관련이 있었다. 이 중 첫 번째 주성분 요소가 전체 변이의 52%에 기여하였는데 이에 해당되는 형질은 장상복엽의 장상렬의 수, 그리고 장상렬의 폭이다. 형태적 변이에 근거한 군집분석에서 우리나라 남부와 중부지방의 두 그룹으로 나누어졌다.

• 여성건강간호학회지
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• 제14권1호
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• pp.56-65
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• 2008

Purpose: The study was to develop an instrument to measure grandmothering stress for Korean day-care grandmothers and to test the validity and reliability of the instrument Method: The items of the instrument were based on a literature review and secondary data, After content validity tests and a pilot test, 20 items were developed. In order to test the reliability and validity of the scale, data were collected from 126 grandmothers. Result: After a factor analysis, five factors and 15 items were selected. These explained 67.2% of the total variance. The first domain was termed 'Health problems', and explained 18.1 % of the total variance, and the second domain of 'Possibility of role substitution' explained 13.8%. The third and the fourth domains were 'Relations with adult children' and 'Grandchildren's characteristics' explaining 12.5% and 12.1 %, respectively. The last domain explained 10.8% of the total variance with the theme 'Restriction of social life' After accomplishing the reliability analysis, Cronbach's alpha coefficient was determined to be .75. Conclusions : This initial step in the development of a Grandmothering Stress Index is valuable to reflect the subject of Grandmothering stress in senior citizens in Korea. Future study should to refine the constitution of the instrument.

• 한국의류학회지
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• 제14권4호
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• pp.245-251
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• 1990

The purposes of the study were to efplain the independent influences of Asthetic Expression and Fashion on aesthetic evaluation in the clothing, to examine which in more important aesthetic components such as line/style, color, textile and detail in aesthetic evaluation in the clothing. Data were obtained from 221 female students living in Seoul area by eight photo-graphs of clothed bodies and a questionnaire. The data were analysied by Pearson's correlation, Analysis of valiables, scheffe-test and Regression analysis. The results of the study were as follows; 1. In the aesthetic evaluation of clothing, the $59.30\%$ of the total variance was explained by Aesthetic Expression, the $20.91\%$ of the total variance was explained by Fashion and $59.68\%$ of the total variance were explained by Aesthetic Expression and Fashion. More important variable of aesthetic evaluation was found to be an Aesthetic Expression. 2. Among aesthetic components such as line/style, color, textile and detail in aesthetic evaluation of the clothing, such general aspects as color and line/style were perceived at first and then specific ones like textile and detail.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2307-2310
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• 2003

In this paper, a method for face recognition based on the wavelet packet decomposition is proposed. In the proposed method, the input image is decomposed by the 2-level wavelet packet transformation and then the face areas are defined by the Integral Projection technique applied to each of the 1-level subband images, HL and LH. After the defined face areas are divided into three areas, called top, bottom, and border, the mean and the variance of the three areas of the approximation image are computed, and the variance of the single predetermined face area for the rest of 15 detail images, from which the feature vectors of statistical measure are extracted. In this paper we use the wavelet packet decomposition, a generalization of the classical wavelet decomposition, to obtain its richer signal analysis features such as discontinuity in higher derivatives, self-similarity, etc. And we have shown that even with very simple statistical features such as mean values and variance we can make an excellent basis for face classification, if an appropriate probability distance is used.

• 말소리와 음성과학
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• 제11권3호
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• pp.23-29
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• 2019

This study acoustically examines the quality of fricatives produced by ten dysarthric speakers with cerebral palsy. Previous similar studies tend to focus only on sibilants, but to obtain a better understanding of how dysarthria affects fricatives we selected a range of samples with different places of articulation and voicing. The Universal Access (UA) Speech database was used to select thirteen words beginning with one of the English fricatives (/f/, /v/, /s/, /z/, /ʃ/, /ð/). The following four measurements were taken for both dysarthric and healthy speakers: phoneme duration, mean spectral peak, variance and skewness. Results show that even speakers with mild dysarthria have significantly longer fricatives and a lower mean spectral peak than healthy speakers. Furthermore, mean spectral peak and variance showed significant group effects for both healthy and dysarthric speakers. Mean spectral peak and variance was also useful for discriminating several places of articulation for both groups. Lastly, spectral measurements displayed important group differences when taking severity into account. These findings show that in general there is a degradation in the production of fricatives for dysarthric speakers, but difference will depend on the severity of dysarthria along with the type of measurement taken.

• Communications for Statistical Applications and Methods
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• 제9권3호
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• pp.835-844
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• 2002

For the one-way random model when the ratio of the variance components is of interest, Bayesian analysis is often appropriate. In this paper, we develop the noninformative priors for the ratio of the variance components under the balanced one-way random effect model. We reveal that the second order matching prior matches alternative coverage probabilities up to the second order (Mukerjee and Reid, 1999) and is a HPD(Highest Posterior Density) matching prior. It turns out that among all of the reference priors, the only one reference prior (one-at-a-time reference prior) satisfies a second order matching criterion. Finally we show that one-at-a-time reference prior produces confidence sets with expected length shorter than the other reference priors and Cox and Reid (1987) adjustment.

• Nuclear Engineering and Technology
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• 제31권3호
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• pp.257-266
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• 1999

A simplified statistical methodology is developed in order to both reduce over-conservatism of deterministic methodologies employed for PWR fuel rod internal pressure (RIP) calculation and simplify the complicated calculation procedure of the widely used statistical methodology which employs the response surface method and Monte Carlo simulation. The simplified statistical methodology employs the system moment method with a deterministic approach in determining the maximum variance of RIP The maximum RIP variance is determined with the square sum of each maximum value of a mean RIP value times a RIP sensitivity factor for all input variables considered. This approach makes this simplified statistical methodology much more efficient in the routine reload core design analysis since it eliminates the numerous calculations required for the power history-dependent RIP variance determination. This simplified statistical methodology is shown to be more conservative in generating RIP distribution than the widely used statistical methodology. Comparison of the significances of each input variable to RIP indicates that fission gas release model is the most significant input variable.

• 한국기계가공학회지
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• 제19권6호
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• pp.9-16
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• 2020

This study aims to assess the effects of specimen thickness (ST) on fatigue crack growth in the early stages of crack propagation and near failure in magnesium alloys. The analysis of variance (ANOVA) method was adopted because fatigue crack propagation in magnesium alloys exhibits statistical behavior. The equality of variance test and residual diagnostics were performed on the grown cracks to confirm the validity of ANOVA by verifying the normal distribution and mutual independence of the residuals and their homoscedasticity. ANOVA confirmed that ST heavily impacts crack growth; i.e., when ST is smaller, cracks grow faster in the early crack propagation stage and break more quickly before the formation of larger cracks. We found that ST significantly affects fatigue crack growth in the early crack propagation stage and near the failure stage in magnesium alloys. The regression model was also used to predict crack formation near the failure stage.