• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.103-110
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• 2008

A reliable extraction of welded area is the precedent task before the detection of weld defects in industrial radiography. This paper describes an attempt to detect and extract the welded features of steel tubes from the computed radiography(CR) images. The statistical properties are first analyzed on over 160 sample radiographic images which represent either weld or non-weld area to identify the differences between them. The analysis is then proceeded by pattern classification to determine the clustering parameters. These parameters are the width, the functional match, and continuity. The observed weld image is processed line by line to calculate these parameters for each flexible moving window in line image pixel set. The local statistic line-clustering method is used as the classifier to recognize each window data as weld or non-weld cluster. The sequential procedure is to track the edge lines between two distinct regions by iterative calculation of threshold, and it results in extracting the weld feature. Our methodology is concluded to be effective after experiment with CR weld images.

• The Journal of Society for e-Business Studies
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• v.16 no.4
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• pp.301-319
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• 2011

Blog plays an important role as new type of knowledge base distinguishing from traditional web resource. While information resources in their existing website dealt with a wide range of topics, information resources of the blog are concentrated in specific units of information depending on the user's interests and have the criteria of classification forresources published by tagging. In this research, we build a tag hierarchy utilizing title keywords and tags of the blog, and propose apost clustering methodology applying the tag hierarchy. We then generate the tag hierarchy reflected the relationship between tags and develop the tag clustering methodology according to tag similarity. In this paper, we analyze the possibility of applying the proposed methodology with real-world examples and evaluate its performances through developed prototype system.

• The Research Journal of the Costume Culture
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• v.15 no.4
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• pp.569-579
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• 2007

The purpose of the present study was to understand the clothing behavior of high school girls, and to analyze the differences of the behavior in accordance with their family self-concept and residential area. The study was implemented through a normative-descriptive survey method using a questionnaire. The survey was conducted in April 2006, and the sample consisted of 462 girls from 5 high schools. The data were analyzed by t-test, factor analysis, and cluster analysis. The results are as follows: I. In general, the family self-concept of high school girls was considerably positive, and the group from the Gangbuk area showed a more positive family self-concept than the group from Gangnam. 2. The group from Gangnam displayed a higher score in conformity, fashionability, and economy than the group from Gangbuk did. In terms of personality, the group from Gangbuk showed a higher score than the group from Gangnam. 3. The group having a more positive family self-concept showed a higher score in aspects of personality and psychological dependency. In the areas of conformity and fashionability, the group having a more positive family self-concept manifested a lower score. 4. In the case of the group having a more positive family self-concept, the girls from Gangnam, more than the group from Gangbuk, evidenced a higher score in conformity and fashionability, but showed a lower score in personality. In the case of the group having a lower score regarding family self-concept, the girls from Gangnam, more than those from Gangbuk, showed a higher score in conformity, fashionability, and economy. On the other hand, the personality score of the girls from Gangnam was lower than that of the Gangbuk group. Considering the results of the study mentioned above, it could be said that the clothing behavior of high school girls is different according to their family self-concept and residential area, and such clothing behavior could be used as a cue to understanding their family self-concept.

• Journal of Korea Water Resources Association
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• v.51 no.5
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• pp.383-393
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• 2018

The regional frequency analysis is the method which uses not only sample of target station but also sample of neighborhood stations in which are classified as hydrological homogeneous regions. Consequently, identification of homogeneous regions is a very important process in regional frequency analysis. In this study, homogeneous regions for regional frequency analysis of precipitation were identified by the self-organizing map (SOM) which is one of the artificial neural network. Geographical information and hourly rainfall data set were used in order to perform the SOM. Quantization error and topographic error were computed for identifying the optimal SOM map. As a result, the SOM model organized by $7{\times}6$ array with 42 nodes was selected and the selected stations were classified into 6 clusters for rainfall regional frequency analysis. According to results of the heterogeneity measure, all 6 clusters were identified as homogeneous regions and showed more homogeneous regions compared with the result of previous study.

• Journal of the Korea Convergence Society
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• v.5 no.3
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• pp.23-27
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• 2014

In recent times, there is an increasing interest in wireless charge of smartphones and devices, and many companies are developing wireless charges. The range of application of wireless charge would be expanded to almost all electronics, including not only mobile devices, but also notebook computers and vacuum cleaners. On-line electric vehicles are to be launched in the market this year in a massive scale. As such wireless charge-related markets are inexhaustible. Wireless charge is included in the world's top 10 promising technologies, and its rapid growth is expected to have annual growth by more than 100%. However, there's a need to establish a safe environment, by analyzing security threats to technical limitations and harmfulness to human body, and arrange institutional compliments. The development of communication method for a variety of wireless charging are delivering comfortable and safe information. This paper aims to examine the factors to threaten electric vehicle, which are usually intruded through network system and analyzes security threats to and security requirements for magnetic resonance mode-based wireless charge in mobile devices, and suggests security requirements.

• Culinary science and hospitality research
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• v.21 no.4
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• pp.271-283
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• 2015

The purpose of current study was to find differences of selected attributes and visitors of responses according to their lifestyle as perceived by Pocheon Yidong-BBQ-Galbi Festival participants. Survey method was employed and total 370 data was used for statistical analysis. The results of factor analysis showed that three factors were extracted from lifestyle(Activity, Example, Commonness), and four factors were found from festival selection attribute(Food, Service, Program, Cleanliness). In addition, three clusters(Outgoing personality, Gentle character, Normal character) were extracted from the result of cluster analysis. The result of chi-square shows that selection attributes are significantly different by clusters of festival. Therefore the festival host need to focus on various kinds of BBQ along with diverse foods and activities to make attractive cultual experience festival for visitors who visited with family. Additionally, all selection attributes except clearness have significantly influence on responsive relationship. Thus, the organizer should make an effort to provide high quality of various selection attributes. Current study will be contribute to develop various and fascinating local festival expecially related to food.

• Korean Journal of Health Education and Promotion
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• v.26 no.4
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• pp.71-81
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• 2009

Objectives: This study furthers the currents understanding of alcohol use disorders, stress, mental health status and suicide among Seoul citizens. This study is to identify differences according to socio-demographic variables and variables which affect stress, mental status and suicide for developing mental health programs. Methods: The study subjects using cluster-stratified sampling method were 1234 adults over 19 years old from 17 dong, S-Ku in Seoul City. A cross-sectional study with face-to-face interview was used to collect data. A questionnaire measuring socio-demographic variables, Symptom Checklist-90-Revised (SCL-90-R) and psychosocial wellbeing index-short form (PWI-SF) was utilized. Results: Three findings in this study were discussed: (1) The prevalence of problem drinking and alcohol dependence and AUDIT score were significantly higher among male, younger age, and high level of education and income; (2) AUDIT score were related with stress, all 9 symptoms of SCL-R and suicide plan; (3) Problem drinkers were more likely to have 2.5 times of anxiety, 3.0 times of hostility, and 2.4 times psychoticism than non alcohol problem drinkers. Alcohol dependence drinkers were more likely to have 1.9 times of high risk group of stress, 4.1 times of obsessive-compulsive, 4.7 times of anxiety, 5.5 times of hostility, and 2.3 times psychoticism than non alcohol dependence drinkers. Conclusion: The findings suggest that the future intervention of Mental Health programs should be carefully designed and tailored by socio-demographic variables.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1524-1531
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• 2004

This study analyzes a load balancing technique using Round Robin Algorithm. The study uses two software packages (Packet Capture and Round Robin Test Package) to check packet volume from Virtual Network structure (data generator, virtual server, Server1,2,3), and finds out traffic distribution toward Server1,2 and 3. The functions of implemented Round Robin Load Balancing Monitoring System include round robin testing, system monitoring, and graphical indication of data transmission and packet volume. As the result of the study shows, Round Robin Algorithm allows servers to ensure definite traffic distribution, unless incoming data loads differ much. Although error levels are high in some cases, they were eventually alleviated by repeated tests for a long period of time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.9
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• pp.1731-1737
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• 2017

K Nearest Neighbor Join (KNN Join) is a simple yet effective method in machine learning. It is widely used in small dataset of the past time. As the number of data increases, it is infeasible to run this model on an actual application by a single machine due to memory and time restrictions. Nowadays a popular batch process model called MapReduce which can run on a cluster with a large number of computers is widely used for large-scale data processing. Hadoop is a framework to implement MapReduce, but its performance can be further improved by a new framework named Spark. In the present study, we will provide a KNN Join implement based on Spark. With the advantage of its in-memory calculation capability, it will be faster and more effective than Hadoop. In our experiments, we study the influence of different factors on running time and demonstrate robustness and efficiency of our approach.

• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.83-89
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• 2005

To investigate the vegetation structure of mountain ridge from Bubong to Poamsan, 16plots$(400m^2)$ set up with random sampling method were surveyed. Two groups of Quercus mongolica-Pinus densiflora community, Quercus variabilis-Pinus densiflora-Quercus mongolica community were classified by cluster analysis. Quercus mongolica was a major woody plant species in the ridge area from Bubong to Poamsan, and Quercus variabilis and Pinus densiflora were partly occupied in lower elevations. High positive correlations were proved between Lespedeza maximowixcii and Pinus koraiensis, Fraxinus sieboldiana and Rhododendron mucronulatum, Acer mono and Weigela subsessilis, and relatively high negative correlations were proved between Symplocos chinensis for. pilosa and Fraxinus sieboldiana, Rhododendron mucronulatum. Species diversity(H') of investigated groups were ranged from $0.9066\~1.0821$, and it was relatively low value compared to that of mountain ridge area of other national parks.