• 제목/요약/키워드: Sample Size

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국내 의류상품개발과정에서 직종별 업무관여도 비교 - 테크니컬 디자인 업무 중심으로 - (Work Involvement Study of Each Job on Technical Design in Garment Development Process in South Korea)

  • 김보아;남윤자;이재일;윤미경
    • 한국의류산업학회지
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    • 제18권5호
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    • pp.658-667
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    • 2016
  • The purpose of this study is 1) to research how practitioners in fashion industry in South Korea perceive concepts of Technical Design/Designer, 2) to compare and analyze issues at work by occupation, 3) to research specific works in garment development process, and 4) to compare and analyze work involvement by occupation, type of a company and etc, and 5) to propose the role of Technical Designers in apparel companies in South Korea. There were two methods to conduct this study, which were in-depth interview and survey. Both methods were conducted to designers, merchandisers, pattern makers, technical designers, and production coordinators. Frequency analysis, ANOVA, Duncan test, and Factor analysis were performed to get results by using SPSS 18.0 program. The results are following. There were 50 works during garment development process from the result of in-depth interview, and 6 factors were obtained from the result of Factor analysis, which were 'Works about Sample in Sample Development Process', 'Works about Product's Pattern and Size Spec', 'Works about Development of Garment's Design', 'Works about Planning of Product Development and Management of Product in Stock', 'Works about Production Process', and 'Preparation Works for Sample Development'. In conclusion, technical designer in apparel companies in South Korea should be in charge of works about sample in sample development process and decision making of product' size spec, which is included in works about product's pattern and size spec. Also, they should complete technical package after product is developed by designers.

Effective Sample Sizes for the Test of Mean Differences Based on Homogeneity Test

  • Heo, Sunyeong
    • 통합자연과학논문집
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    • 제12권3호
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    • pp.91-99
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    • 2019
  • Many researchers in various study fields use the two sample t-test to confirm their treatment effects. The two sample t-test is generally used for small samples, and assumes that two independent random samples are selected from normal populations, and the population variances are unknown. Researchers often conduct F-test, the test of equality of variances, before testing the treatment effects, and the test statistic or confidence interval for the two sample t-test has two formats according to whether the variances are equal or not. Researchers using the two sample t-test often want to know how large sample sizes they need to get reliable test results. This research gives some guidelines for sample sizes to them through simulation works. The simulation had run for normal populations with the different ratios of two variances for different sample sizes (${\leq}30$). The simulation results are as follows. First, if one has no idea equality of variances but he/she can assume the difference is moderate, it is safe to use sample size at least 20 in terms of the nominal level of significance. Second, the power of F-test for the equality of variances is very low when the sample sizes are small (<30) even though the ratio of two variances is equal to 2. Third, the sample sizes at least 10 for the two sample t-test are recommendable in terms of the nominal level of significance and the error limit.

얼굴인식해석의 Small Sample Size 문제 해결을 위한 Resampling 방법 (A Resampling Method for Small Sample Size Problems in Face Recondition)

  • 오재현;곽노준;최태영
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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    • pp.172-173
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    • 2008
  • LDA를 이용한 얼굴 인식에서 발생하는 small sample sire 문제를 해결하기 위해서 regularization method를 주로 사용한다. 이 방법을 사용하게 되면 클래스 내 분산행렬의 특이성을 없앨 수 있지만, 클래스 내 분산행렬과 단위행렬 $\alpha$를 곱한 값을 더하는 과정에서 $\alpha$의 값을 임의적으로 정해주어야 되고 이 값에 따라 인식률이 개선되지 않을 수 있다는 문제점이 있다. Resampling 개념을 이용하여 학습 데이터의 수를 늘리게 되면 regularization method보다 개선된 인식률을 얻을 수 있다. 또한 경험적으로 $\alpha$값을 정해 주어야 하고, $\alpha$값에 따라 인식률의 변통이 생길 수 있는 단점이 개선되는 효과를 얻을 수 있다.

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왜도(Skewness)가 심한 모집단에서의 절사법효과에 관한 연구 (A study for the efficiency of the cut-off method in highly skewed populations)

  • 한근식;김용철
    • 응용통계연구
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    • 제9권2호
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    • pp.161-169
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    • 1996
  • 표본크기 결정은 표본설계시 중요한 부분이며 정도(Precision)를 높이면서 비용, 시간 등을 고려하여 최적화(Optimal)된 표본의 크기를 구하려 할 때 모집단 분포가 심한 왜도(highly skewed)를 보이거나 소수의 모집단요소들이 모집단총계의 대부분을 차지하는 경우가 있다. 이에 대해 Neyman의 최적할당법과 절사법(cut-off method) 응용 방법의 효율성을 사례를 이용하여 비교하였다.

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A Cross-cultural study of Body Image Perceptions between Korean and British University Students

  • Kim, Bu-Yong;Lee, Seunghee
    • 패션비즈니스
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    • 제19권6호
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    • pp.14-27
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    • 2015
  • This study explores the comparison of body image, body satisfaction, and clothing behaviors between Korean and British young women. Body image was measured by two methods: visual and verbal. For the data analysis, the Statistical Package for Social Science (SPSS) Version 16.0 for Windows was used to provide descriptive statistics, an independent sample t-test, and paired sample t- tests were applied in this study. Our results show that Korean and British female college students perceived ideal-body images that were smaller than their self defined body images. The ideal and self-images were significantly different in both groups. Both groups were dissatisfied with their own body size. The study was limited to a small sample size. Future studies using more participants from a more diverse age group and ethnic groups are recommended. The study will help marketers and retailers develop new products and new markets aimed at Korean and British women related to body image and body satisfaction.

An Estimator of Population Mean Based on Balanced Systematic Sampling When Both the Sample Size and the Reciprocal of the Sampling Fraction are Odd Numbers

  • Kim, Hyuk-Joo
    • Communications for Statistical Applications and Methods
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    • 제14권3호
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    • pp.667-677
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    • 2007
  • In this paper, we propose a method for estimating the mean of a population which has a linear trend, when both n, the sample size, and k, the reciprocal of the sampling fraction, are odd numbers. The proposed method, not having the drawbacks of centered systematic sampling, centered modified sampling and centered balanced sampling, consists of selecting a sample by balanced systematic sampling and estimating the population mean by using interpolation. We compare the efficiency of the proposed method and existing methods under the criterion of the expected mean square error based on the infinite superpopulation model.

바닥충격음 완충재의 동탄성계수 특성 및 측정 영향인자 (A Study On the Property and Influence Factor in Measuring of the Dynamic Stiffness of Damping Materials)

  • 김경우;최현중;강재식;양관섭
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.1256-1259
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    • 2006
  • The purpose of this study was to investigate the current status and influence factor in measuring the dynamic stiffness of damping materials. The property of the dynamic stiffness of damping materials was tested and analysed in condition such as the size of test samples and the change of relative humidity in heating chamber. Test results showed that the dynamic stiffness of after-heating was lower than that of before-heating in most samples and the change of relative humidity in heating chamber got little influence of the dynamic stiffness. The resonant frequency of test sample decreased $2{\sim}7Hz$ as the decrease of the size of sample. Because it was increased that total mass per unit area of sample, the change of dynamic stiffness had little influence.

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Permutation Analysis of Split-Half Reliability Coefficient

  • Um, Yonghwan
    • 한국컴퓨터정보학회논문지
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    • 제22권7호
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    • pp.133-139
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    • 2017
  • In this paper, we describe a permutation procedure in which we compute a resampling probability value and empirical quantile limits for Split-Half measure of internal reliability. We use the Split-Half reliability coefficient given by two simple methods, the Spearman-Brown formula and the two-part coefficient alpha. The use of a permutation test for Split-Half reliability coefficient is highlighted as a valuable tool when the sample sizes are small and necessary assumptions cannot be met. The permutation tests for Split-Half reliability coefficient are illustrated with an example analysis of two survey data with a sample size of 15 and 35, respectively, and a hypothetical data with a sample size of 5.

INVITED PAPER MULTIVARIATE ANALYSIS FOR THE CASE WHEN THE DIMENSION IS LARGE COMPARED TO THE SAMPLE SIZE

  • Fujikoshi, Yasunori
    • Journal of the Korean Statistical Society
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    • 제33권1호
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    • pp.1-24
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    • 2004
  • This paper is concerned with statistical methods for multivariate data when the number p of variables is large compared to the sample size n. Such data appear typically in analysis of DNA microarrays, curve data, financial data, etc. However, there is little statistical theory for high dimensional data. On the other hand, there are some asymptotic results under the assumption that both and p tend to $\infty$, in some ratio p/n ${\rightarrow}$c. The results suggest that the new asymptotic results are more useful and insightful than the classical large sample asymptotics. The main purpose of this paper is to review some asymptotic results for high dimensional statistics as well as classical statistics under a high dimensional asymptotic framework.

표본크기에 제약이 있는 누적 축차관리도 (Cumulative Sequential Control Charts with Sample Size Bound)

  • 장영순;배도선
    • 대한산업공학회지
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    • 제25권4호
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    • pp.448-458
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    • 1999
  • This paper proposes sequential control charts with an upper bound on sample size. Existing sequential control charts have no restriction on the number of observations at a sampling point. For situations where sampling and testing an item is time-consuming or expensive, sequential control charts may not be directly applied. When the number of observations in a sampling point reaches the upper bound and there is no out-of-control signal, the proposed cumulative sequential control chart defers the decision to the next sampling point of which starting value is the value of the current statistic. Two Markov chains, inner and outer chains, are used to derive the formulas for evaluating the performance of the proposed chart. It is compared with $\bar{X}$ and cumulative sum control charts with fixed and variable sample sizes. The fast initial response (FIR) feature is studied. Guidelines for the design of the proposed charts are also given.

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