• Title/Summary/Keyword: Borrowing strength

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Bayes tests of independence for contingency tables from small areas

  • Jo, Aejung;Kim, Dal Ho
    • Journal of the Korean Data and Information Science Society
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    • v.28 no.1
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    • pp.207-215
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    • 2017
  • In this paper we study pooling effects in Bayesian testing procedures of independence for contingency tables from small areas. In small area estimation setup, we typically use a hierarchical Bayesian model for borrowing strength across small areas. This techniques of borrowing strength in small area estimation is used to construct a Bayes test of independence for contingency tables from small areas. In specific, we consider the methods of direct or indirect pooling in multinomial models through Dirichlet priors. We use the Bayes factor (or equivalently the ratio of the marginal likelihoods) to construct the Bayes test, and the marginal density is obtained by integrating the joint density function over all parameters. The Bayes test is computed by performing a Monte Carlo integration based on the method proposed by Nandram and Kim (2002).

Evaluation on Strength Characteristics of Automobile Steel Sheet by Electrode Resistance Spot Weld (전기저항 점용접한 자동차 강판의 강도특성평가)

  • Yoon, Han-Ki;Hu, Kwan-Do;Ryu, Deok-Seang
    • Journal of Power System Engineering
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    • v.17 no.4
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    • pp.115-119
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    • 2013
  • The resistance spot welding of high strength steel degrades the weldability because of its high strength with rich chemical composition and coating layer to protect from corrosion. And the weld Expulsion is prone to occur and severely affect the nugget guality when the initial gap between automatic borrowing galvanied steel sheets(SGARC35) and Zn-coateel trip steels(GA580TRIP and GA980 TRIP) exist in resistance spot welding(RSW). RSW is one of the most popular welding processes used to join sheet metals. but weld guality sometimes do creases due to welding condition. in this paper to verity tue weldability using spot welding with the hemispherically concaved electrode, tensile shear strength and cross-tensile strength were measured by a universal test machine. in addition, the nugget size on cross-sectional area of the weld was observed by optical and electron microscopy. As a result, the nugget size of this specimen is increased with increasing welding current and Max load of tensile-shear strength is increased with welding current is increasing.

The Expression of Metonymy in Fashion Illustration (패션 일러스트레이션의 환유적 표현방법)

  • 최정화
    • Journal of the Korean Society of Clothing and Textiles
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    • v.28 no.11
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    • pp.1415-1425
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    • 2004
  • The purpose of this study was to analyze a theoretical frame of expressional area, the characteristics and the effects which is applied to fashion illustration by metonymic theory. The theoretical frame of expressional area was analyzed by category analysis and 150 fashion illustrations from 1900 to 1999 were analyzed by contents analysis. The results of this study were as follows: The expressions of metonymy were categorized by close-up, realistic expression, omission, borrowing of past style, simplification and deconstruction. First, close-up was presented as emphasis of small part of fashion by cutting the scenes, snapshot, emphasis, etc. Second, realistic expression was presented as description of related circumstance with fashion message through perspective and realistic description of circumstance related to figures. Third, omission was presented as seeking of essential core by removing color, pattern, texture or by omitting body and as emphasis of communication about dominant fashion message. Fourth, borrowing of past style was presented as reminding us of background of the past. Fifth, simplification was presented as using of form or color to alleviate tension of object and to restore the essential reality. Sixth, deconstruction was presented as fragmenting of image, flattening of body and clothing, weakness of form, and strength of color. In conclusion, metonymy made by experience system of thinking based on the reality, have extended expressional territory in pre-existing fashion illustration. And these ways not only will provide fashion image as illustrator's subjective intention and theoretical system of expression of message, but also will be useful way to strengthen communication for easier interpretation of fashion illustration.

Estimation of Dynamic Effects of Price Increase on Sales Using Bayesian Hierarchical Model (베이지안 다계층모형을 이용한 가격인상에 따른 판매량의 동적변화 추정 및 예측)

  • Jeon, Deok-Bin;Park, Seong-Ho
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2005.05a
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    • pp.798-805
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    • 2005
  • Estimating the effects of price increase on a company's sales is important task faced by managers. If consumer has prior information on price increase or expect it, there would be stockpiling and subsequent drops in sales. In addition, consumer can suppress demand in the short run. Above factors make the sales dynamic and unstable. We develop a time series model to evaluate the sales patterns with stockpiling and short term suppression of demand and also propose a forecasting procedure. For estimation, we use panel data and extend the model to Bayesian hierarchical structure. By borrowing strength across cross-sectional units, this estimation scheme gives more robust and reasonable result than one from the individual estimation. Furthermore, the proposed scheme yields improved predictive power in the forecasting of hold-out sample periods.

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Bayesian Method for Combining Results from Different Poisson Experiments

  • Cho, Jang Sik;Kim, Dal Ho
    • Communications for Statistical Applications and Methods
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    • v.7 no.2
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    • pp.533-540
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    • 2000
  • The problem of information related to I poission experiments, each having a distinct failure rate $\theta$i I=1,2,…,I, is considered. Instead of using a standard exchangeable prior for $\theta$=($\theta$1,$\theta$2,…,$\theta$I), we consider a partition of the experiments and take the $\theta$i's belonging to the same partition subgroup to be exchangeable and the $\theta$i's belonging to distinct subgroups to be independent. And we perform Gibbs sampling approach for Bayesian inference on $\theta$ conditional on a partition. Numerical study using real data is provided.

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Sampling Based Approach for Combining Results from Binomial Experiments

  • Cho, Jang-Sik;Kim, Dal-Ho;Kang, Sang-Gil
    • Journal of the Korean Data and Information Science Society
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    • v.12 no.1
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    • pp.1-9
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    • 2001
  • In this paper, the problem of information related to I binomial experiments, each having a distinct probability of success ${\theta}_i$, i = 1,2, $\cdots$, I, is considered. Instead of using a standard exchangeable prior for ${\theta}\;=\;({\theta}_1,\;{\theta}_2,\;{\cdots},\;{\theta}_I)$, we con-sider a partition of the experiments and take the ${\theta}_i$'s belonging to the same partition subset to be exchangeable and the ${\theta}_i$'s belonging to distinct subsets to be independent. And we perform Gibbs sampler approach for Bayesian inference on $\theta$ conditional on a partition. Also we illustrate the methodology with a real data.

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Estimation and Forecasting of Dynamic Effects of Price Increase on Sales Using Panel Data (패널자료를 이용한 가격인상에 따른 판매량의 동적변화 추정 및 예측)

  • Park Sung-Ho;Jun Duk-Bin
    • Journal of the Korean Operations Research and Management Science Society
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    • v.31 no.2
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    • pp.157-167
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    • 2006
  • Estimating the effects of price increase on a company's sales is important task faced by managers. If consumer has prior information on price increase or expects it, there would be stockpiling and subsequent drops in sales. In addition, consumer can suppress demand in the short run. These factors make the sales dynamic and unstable. In this paper we develop a time series model to evaluate the sales patterns with stockpiling and short-term suppression of demand and also propose a forecasting procedure. For estimation, we use panel data and extend the model to Bayesian hierarchical structure. By borrowing strength across cross-sectional units, this estimation scheme gives more robust and reasonable result than one from the individual estimation. Furthermore, the proposed scheme yields improved predictive power in the forecasting of hold-out sample periods.

A Bayesian model for two-way contingency tables with nonignorable nonresponse from small areas

  • Woo, Namkyo;Kim, Dal Ho
    • Journal of the Korean Data and Information Science Society
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    • v.27 no.1
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    • pp.245-254
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    • 2016
  • Many surveys provide categorical data and there may be one or more missing categories. We describe a nonignorable nonresponse model for the analysis of two-way contingency tables from small areas. There are both item and unit nonresponse. One approach to analyze these data is to construct several tables corresponding to missing categories. We describe a hierarchical Bayesian model to analyze two-way categorical data from different areas. This allows a "borrowing of strength" of the data from larger areas to improve the reliability in the estimates of the model parameters corresponding to the small areas. Also we use a nonignorable nonresponse model with Bayesian uncertainty analysis by placing priors in nonidentifiable parameters instead of a sensitivity analysis for nonidentifiable parameters. We use the griddy Gibbs sampler to fit our models and compute DIC and BPP for model diagnostics. We illustrate our method using data from NHANES III data on thirteen states to obtain the finite population proportions.

Critical Discussion on the 'Orientalism' in Fashion Culture (패션문화에 나타난 오리엔탈리즘에 대한 비판적 논의)

  • Seo, Bong-Ha
    • Journal of the Korean Society of Clothing and Textiles
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    • v.32 no.6
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    • pp.902-910
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    • 2008
  • A view of the Orientalism that sees the Orient as the inferior Other, characterized by the heterogenic, eccentric, backward, and passive features, has been internalized in the unconsciousness of Westerners. 'Orientalism' which is the cultural device and the system of discourse to put Asia in the fixed frame of dominance was the West European centered term, designating Southwest Asia including South Europe and North Africa as Orient, and contained the idea that non-Western society could progress only with the acceptance of Western civilization. Accordingly, it is need to use this term deliberately. In addition, even though the Asian Look of the West, borrowing the images and costume styles of Asia has lost the original mentality of Asia, it was not initiated from the perception that sees Asia as the inferior Other. Since the Asian Ethnic Look is the Western costume, borrowing the image of Orient and style by being fascinated by Oriental Aesthetics, the attributes of it are different from those of Orientalism. Therefore, it is not appropriate to designate the Asian Ethnic Look as 'Orientalism Fashion' or 'Oriental Look' except for some eccentric manipulation of Asia costume and image. Instead, it is desirable to exchange the term 'Asian Look', 'Asian Fashion', and 'Asian Ethnic Look' upon occasions or the name of individual nation or region can be referred to as preferred alternatives. Today, Asia including Korea is taking the initiative in the World Fashion as one of central axes of World Fashion Industry, and cannot be interpreted from the perspective of West Centrism. Now, it's time to dissolve the dichotomous prejudice of the West centrism on Asia's own strength.