• The KIPS Transactions:PartC
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• v.19C no.3
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• pp.173-178
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• 2012

Recent two security schemes showed that a bloom filter can reduce a message length required for representing multiple MACs. The schemes, however, made message length comparison without considering security level. Since the MAC is intended for security, it is important to let multiple MACs and the bloom filter have the same level of security for making message length comparison. In this paper, we analyze the message length efficiency of bloom filter, compressed bloom filter and multiple MACs, letting them have the same security level.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.10
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• pp.98-103
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• 1997

Given the small bit allocation for motion information in very low bit-rate coding, motion estimation using the block matching algorithm(BMA) fails to maintain an acceptable level of prediction errors. The reson is that the motion model, or spatial transformation, assumed in block matching cannot approximate the motion in the real world precisely with a small number of parameters. In order to overcome the drawback of the conventional block matching algorithm, several triangle-based methods which utilize triangular patches insead of blocks have been proposed. To estimate the motions of image sequences, these methods usually have been based on the combination of optical flow equation, affine transform, and iteration. But the compuataional cost of these methods is expensive. This paper presents a fast motion estimation algorithm using a multiple linear regression model to solve the defects of the BMA and the triange-based methods. After describing the basic 2-D triangle-based method, the details of the proposed multiple linear regression model are presented along with the motion estimation results from one standard video sequence, representative of MPEG-4 class A data. The simulationresuls show that in the proposed method, the average PSNR is improved about 1.24 dB in comparison with the BMA method, and the computational cost is reduced about 25% in comparison with the 2-D triangle-based method.

• Korean Management Science Review
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• v.19 no.2
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• pp.139-153
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• 2002

The Analytic Hierarchy Process (AHP) is known as a very useful decision-making model developed for obtaining the relative weights of alternatives through pairwise comparison in the context of hierarchical structure. In this paper, we propose a method to reflect the reliability of evaluators in the process of pairwise comparison. This method is applied to the evaluation of aerospace technology alternatives. We have conducted a questionnaire survey for S company that is one of the representative aerospace companies in Korea. A questionnaire was designed for obtaining both the priority with considering the reliability of evaluators' importance weights (the modified AHP priority) and the priority with assuming equally reliable evaluators' importance weights (the AHP priority) in order to compare the priority derived by each of two methods. The result shows that there exists the difference hard to neglect between the final priorities gained by two methods.

• Journal of the Korean Statistical Society
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• v.29 no.2
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• pp.155-168
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• 2000

Regarding to multiple comparison problem (MCP) of k normal population variances, we suggest a Bayesian method for calculating posterior probabilities for various hypotheses of equality among population variances. This leads to a simple method for obtaining pairwise comparisons of variances in a statistical experiment with a partition on the parameter space induced by equality and inequality relationships among the variances. The method is derived from the fact that certain features of the hierarchical nonparametric family of Dirichlet process priors, in general, make it amenable to solving the MCP and estimating the posterior probabilities by means of posterior simulation, the Gibbs sampling. Two examples are illustrated for the method. For these examples, the method is straightforward for specifying distributionally and to implement computationally, with output readily adapted for required comparison.

• Communications for Statistical Applications and Methods
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• v.12 no.2
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• pp.305-312
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• 2005

In the cluster analysis, Hotelling's $T^2$ can be used to estimate the unknown number of clusters based on the idea of multiple comparison procedure. Especially, its threshold is obtained according to the probability of committing the type one error. Examples are used to compare Hotelling's $T^2$ with other classical location test statistics such as Sum-of-Squared Error and Wilks' $\Lambda$ The hierarchical clustering is used to reveal the underlying structure of the data. Also related criteria are reviewed in view of both the between variance and the within variance.

• Communications for Statistical Applications and Methods
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• v.30 no.3
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• pp.331-341
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• 2023

Handling missing values in data analysis is essential in constructing a good prediction model. The easiest way to handle missing values is to use complete case data, but this can lead to information loss within the data and invalid conclusions in data analysis. Imputation is a technique that replaces missing data with alternative values obtained from information in a dataset. Conventional imputation methods include K-nearest-neighbor imputation and multiple imputations. Recent methods include missForest, missRanger, and mixgb ,all which use machine learning algorithms. This paper compares the imputation techniques for datasets with mixed datatypes in various situations, such as data size, missing ratios, and missing mechanisms. To evaluate the performance of each method in mixed datasets, we propose a new imputation performance measure (IPM) that is a unified measurement applicable to numerical and categorical variables. We believe this metric can help find the best imputation method. Finally, we summarize the comparison results with imputation performances and computational times.

• Journal of the Korea Fashion and Costume Design Association
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• v.15 no.3
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• pp.1-17
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• 2013

The purpose of this study was to identify the relationships among self-esteem, physical appearance comparison, media concern, sociocultural attitude toward appearance, body attitudes, and life satisfaction. Data were collected from a convenience sample of 232 female undergraduate students. Data were analyzed using factor analysis, correlation, and multiple regression. The result showed that there was a correlation between physical appearance comparison and media concern. Self-esteem, physical appearance comparison, and media concern had an indirect influence on body attitudes through sociocultural attitude toward appearance. Self-esteem and physical appearance comparison had a direct effect on body attitude. All variables did not have an influence on life satisfaction, except self-esteem.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3605-3610
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• 2016

Background: Histone acetylation in chromatin structures plays a key role in regulation of gene transcription and is strictly controlled by histone acetyltransferase (HAT) and deacetylase (HDAC) activities. HDAC deregulation has been reported in several cancers. Materials and Methods: The expression of 10 HDACs (including HDAC class I and II) was studied by quantitative reverse transcription-PCR (qRT-PCR) in a cohort of mesenchymal stem cells (MM-MSCs) from 10 multiple myeloma patients with a median age 60y. The results were compared with those obtained for normal donors. Then, a coculture system was performed between MM-MSCs and u266 cell line, in the presence or absence of sodium butyrate (NaBT), to understand the effects of HDAC inhibitors (HDACi) in MM-MSCs on multiple myeloma cases. Also, the interleukin-6 (IL-6) and vascular endothelial growth factor (VEGFA) gene expression level and apoptotic effects were investigated in MM-MSCs patients and control group following NaBT treatment. Results: The results indicated that upregulated (HDACs) and downregulated (IL6 and VEGFA) genes were differentially expressed in the MM-MSCs derived from patients with multiple myeloma and ND-MSCs from normal donors. Comparison of the MM-MSCs and ND-MSCs also showed distinct HDACs expression patterns. For the first time to our knowledge, a significant increase of apoptosis was observed in coculture with MM-MSCs treated with NaBT. Conclusions: The obtained findings elucidate a complex set of actions in MSCs in response to HDAC inhibitors, which may be responsible for anticancer effects. Also, the data support the idea that MSCs are new therapeutic targets as a potential effective strategy for MM.

• Journal of Korean Academy of Nursing
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• v.36 no.3
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• pp.571-580
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• 2006

Purpose: This study was to compare the effects among Tai-Chi exercise, aquatic Exercise, and a self-help program for knee osteoarthritis patients on symptoms of arthritis, muscle strength, balance, and difficulty of performing activities. Method: There were 50 final subjects50. A non-equivalent pretest-posttest design was used. The collected data was analyzed using SPSS for Window. One-way ANOVA and Scheffe's multiple comparison test were used 8weeks after each program. Result: There were significant differences in joint pain(p=.000), stillness (p=.001), knee extensor peak torque(p=.006), knee flexor(p=.002), and difficult of performing activity (p=.000), but there was no significant difference in balance(p=.648). The Tai-Chi group was significantly different from the self-help group for knee extensor peak torque, knee flexor and stiffness on Scheffe's multiple comparison tests. In addition, the Tai Chi group or aquatic group were significantly different from the self-help group for difficulty of performing activities(p<0.05). Conclusion: There are significant differences in the effects of the nursing intervention among the three groups. The Tai Chi group and aquatic group were significantly different from the self-help group. However, it seems that Tai-chi exercise may be more suitable than aquatic exercise in osteoarthritis exercise programs. Further studies with a longitudinal study are necessary to confirm the longer exercise period.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2001.11a
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• pp.155-155
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• 2001