• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.948-958
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• 2010

Human body signals collected by the MRI system are very weak, such that they may be easily affected by either external noise or system instability while being imaged. Therefore, this paper analyzes the nonuniformity caused by a design of the RF receiving coil in a low-magnetic-field MRI system, and proposes an efficient method to improve the image uniformity. In this paper, a method for acquiring 3D bias volume data by using phantom data among various methods for correcting such nonuniformity in MRI image is proposed, such that it is possible to correct various-sized images. It is shown by simulations that images obtained by various imaging methods can be effectively corrected using single bias data.

• Research in Community and Public Health Nursing
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• v.32 no.2
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• pp.140-149
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• 2021

Purpose: This study aimed to identify factors (biological, psychological, interpersonal, and contextual factors) associated with the weight bias internalization of the Korean girls in early adolescence. Methods: This study used a cross-sectional design. Data was collected from 233 girls aged 12~14 years with a self-reported questionnaire. With multiple regression analysis, the factors associated with the weight bias internalization of the girls in early adolescence were analyzed. Results: Of psychosocial factors, fear to fat (anti-fat attitude) (β=.43, p<.001) was associated with the weight bias internalization of the girls in early adolescence. In addition, attachment with teachers (β=-.11, p=.029) of an interpersonal factor and perceived socio-cultural pressure regarding weight control (β=.34, p<.001) of a contextual factor were associated with the weight bias internalization of the girls in early adolescence. Conclusion: For releasing the weight bias internalization of the girls in early adolescence, decreasing anti-fat attitude and socio-cultural pressure regarding weight control should be primarily required through social efforts including community and school based interventions.

• Journal of the Korean Data and Information Science Society
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• v.24 no.4
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• pp.815-824
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• 2013

Traditional Pearson chi-squared test is not appropriate for the data collected by the complex sample design. When one uses the traditional Pearson chi-squared test to the complex sample categorical data, it may give wrong test results, and the error may occur not only due to the biased variance estimators but also due to the biased point estimators of cell proportions. In this study, the design based consistent Wald test statistics was derived for k-population homogeneity test, and the traditional Pearson chi-squared test statistics was partitioned into three parts according to the causes of error; the error due to the bias of variance estimator, the error due to the bias of cell proportion estimator, and the unseparated error due to the both bias of variance estimator and bias of cell proportion estimator. An analysis was conducted for empirical results of the relative size of each error component to the Pearson chi-squared test statistics. The second year data from the fourth Korean national health and nutrition examination survey (KNHANES, IV-2) was used for the analysis. The empirical results show that the relative size of error from the bias of variance estimator was relatively larger than the size of error from the bias of cell proportion estimator, but its degrees were different variable by variable.

• Journal of Fashion Business
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• v.11 no.1
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• pp.26-37
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• 2007

Madeleine Vionnet(1876$\sim$1975, France),the most prominent figure of the 20th century draping, started her apprentice in France in 1888 and expressed feminity of adult products through her various works until she closed the house in 1940. The feminine designs of the adult style appeared in 1930s, whose characteristics were silhouette and details that emphasize the body, and bias designs. Not only Vionnet, but also Chanel and Schiaparelli were the representative female designers at that time. The preliminary researches of Vionnet designs were mostly focused on her cutting methods. This paper purports to examine Vionnet's bias cutting method, to compare Vionnet with female designers of Chanel and Schiaparelli who led the mode of 1930s with feminine designs for the adult products in that period, and then to attempt creative designs by use of bias cutting.

• The Korean Journal of Applied Statistics
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• v.17 no.1
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• pp.61-73
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• 2004

Rotation sampling designs may be classified into two categories. The first type uses the same sample unit for the entire life of the survey. The second type uses the sample unit only for a fixed number of times. In both type of designs, the entire sample is partitioned into a finite number(=G) of rotation groups. This paper is generalization of the first type designs. Since the generalized design can be identified by only G rotation groups and recall level 1, we denote this rotation system as l/G rotation design. Under l/G rotation design, variance and mean squared error (MSE) of generalized composite estimator are derived, incorporating two type of biases and exponentially decaying correlation pattern. Compromising MSE's of some selected l/G designs, we investigate design efficiency, design gap effect, ans the effects of correlation and bias.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.4
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• pp.240-248
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• 2009

Moore's law has driven silicon technology scale down aggressively, and it results in significant increase of leakage current on nano-meter scale CMOS. Especially, in mobile devices, leakage current has been one of designers' main concerns, and thus many studies have introduced low power methodologies. However, there are few studies to minimize implementation cost in the mixed use of the methodologies to the best of our knowledge. In this paper, we introduce industrial applications of low power design methodologies for the decrease of leakage current. We focus on the design cost reduction of power gating and reverse body bias when used together. Also, we present voltage scale as an alternative to reverse body bias. To sustain gate leakage current, we discuss the adoption of high-$\kappa$ metal gate, which cuts gate leakage current by a factor of 10 in 32 nm CMOS technology. A 45 nm mobile SoC is shown as the case study of the mixed use of low power methodologies.

• Journal of Korean Physical Therapy Science
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• v.30 no.4
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• pp.82-91
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• 2023

Background: Randomized controlled trials (RCTs) provide evidence on the effectiveness and safety of interventions and inform systematic reviews and guideline preparation for clinical application. However, methodological flaws can occur in many RCTs, and Cochrane's risk of bias version 2 (RoB2) can be used to evaluate RCTs' risk of bias (RoB). However, physical therapy RCTs in Korea did not confirm RoB. Therefore, the purpose of this study was to evaluate RoB using RoB2 in RCTs published in the Korean Physical Therapy Journal. Design: Review. Methods: The RCTs subject to evaluation were RCTs published in 11 physical therapy journals in Korea from 2018 to 2022. RoB2 evaluated a total of five domains: bias arising from the randomization process, bias due to deviations from intended interventions, bias due to missing outcome data, bias in measurement of the outcome, and bias in selection of the reported result. Results: A total of 616 RCTs were evaluated. As for bias arising from the randomization process, high risk was the highest at 555 (90.1%), followed by low risk at 41 (6.7%) and some concerns at 20 (3.2%). For bias due to deviations from intended interventions, the proportion of some concerns was the highest at 390 (63.3%), followed by high risk at 218 (35.4%) and low risk at 8 (1.3%). As for the bias due to missing outcome data, the rate of low risk was the highest at 399 (64.8%), followed by high risk at 159 (25.8%) and some concerns at 58 (9.4%). As for bias in measurement of the outcome, high risk was the highest at 294 (47.7%), followed by low risk at 224 (36.4%) and some concerns at 98 (15.9%). In the bias due to missing outcome data, the ratio of high risk was the highest at 610 (99%), followed by low risk at 4 (0.7%) and some concerns at 2 (0.3%). Conclusion: Most of the RoB evaluation results of RCTs published in the Korean Physical Therapy Journal were rated as high risk. Methodological quality of RCTs needs to be improved.

• Communications for Statistical Applications and Methods
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• v.22 no.2
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• pp.137-146
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• 2015

Singh (2013) considered the dual problem to the calibration of design weights to obtain a new generalized linear regression estimator (GREG) for the finite population total. In this work, we have made an attempt to suggest a way to use the dual calibration of the design weights in case of multi-auxiliary variables; in other words, we have made an attempt to give an answer to the concern in Remark 2 of Singh (2013) work. The same idea is also used to generalize the GREG estimator proposed by Deville and S$\ddot{a}$rndal (1992). It is not an easy task to find the optimum values of the parameters appear in our approach; therefore, few suggestions are mentioned to select values for such parameters based on a random sample. Based on real data set and under simple random sampling without replacement design, our approach is compared with other approaches mentioned in this paper and for different sample sizes. Simulation results show that all estimators have negligible relative bias, and the multivariate case of Singh (2013) estimator is more efficient than other estimators.

• Survey Research
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• v.12 no.3
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• pp.25-48
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• 2011

In this paper, we overview the sample design, sampling error, non-response rate and prediction errors of the exit poll conducted for 2010 local elections and discusses how to detect a prediction bias in exit poll. To investigate the bias problem in exit poll in regional(Si-Do) level, we analyze exit poll data for 2007 presidential election and 2006 local elections as well as 2010 local elections in Korea. The measure of predictive accuracy A proposed by Martin et al.(2005) is used to assess the exit poll bias. The empirical studies based on three exit polls clearly show that there exits systematic bias in exit poll and the predictive bias of candidates affiliated to conservative party (such as Hannara-Dang) is serious in the specific regions. The result of this study on systematic bias will be very useful to improving the exit poll methodology in Korea.

• Journal of Digital Convergence
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• v.19 no.1
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• pp.355-360
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• 2021

In this study, the factors of confirmation bias that may occur in the initial user experience stage were analyzed using a honeycomb model by deriving user experience factors for each factor. In the initial user experience stage, confirmation bias occurs in the impression stage. At the processing stage of memory, sensory memory, working memory, and long-term memory, which stores and retrieves selective memory, were closely related. Confirmation bias was classified into visibility, correlation, memory, clarity, and universality in the usability part, and satisfaction, joy, and dissatisfaction were derived as emotional factors. As a result of the analysis with the honeycomb model, visuality, clarity, universality in the usability factor, and joy in the emotional factor had little effect on the confirmation bias, and satisfaction and dissatisfaction were analyzed as the main factors of the confirmation bias in the correlation, memory and emotional factors. This study is meaningful in that it can be usefully used as a reference material for companies that customize design patterns for the factor of confirmation bias.