• Journal of the Korea Society of Computer and Information
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• v.24 no.1
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• pp.1-7
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• 2019

In this paper, we implemented a Wi-Fi based cluster system using raspberry pi for multidisciplinary education. The cluster implementation on the desktop was more difficult to maintain the complexity, big size, high price, power consumption as the number of nodes increased. In this paper, we implemented a cluster using Raspberry Pi, which is developed for educational purposes, to reduce the cost of connecting nodes. In addition, the complexity of system construction is reduced by replacing the connection between each node with Wi-Fi. Also, the inconvenience of configuration due to node increase was reduced. It is expected that the implementation of the cluster will be a good alternative in the educational environment where distributed processing and parallel processing are performed in the embedded environment. Also, it is confirmed that it can be applied to the multidisciplinary education.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.103-109
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• 2013

Mobile ad hoc networks (MANETs) are infrastructure-less and stand-alone wireless networks with dynamic topologies. To support user's safety in MANETs, fundamental and various security services should be supported. Especially in mobile commercial market, one of the major concerns regarding security is user privacy. Recently, researches about security system to protect user privacy in cluster-based MANETs have been introduced. This paper propose a cluster reconfiguration protocol under anonymous cluster-based MANETs to enhance the network stability. The improved anonymous cluster-based MANETs can recover the network structure against abnormal states of clutserheads.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.53.1-53.1
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• 2011

We analyze the halo and galaxy catalogs from the Millennium simulations at redshifts z=0, 0.5, 1 to determine the alignment profiles of cluster galaxies in terms of the matter density correlation coefficient and discuss a cosmological implication our result has for breaking parameter degeneracies. For each selected cluster, we measure the alignment between the major axes of the pseudo inertia tensors from all satellites within cluster's virial radius and from only those satellites within some smaller radius. Then we average the measured values over the similar-mass sample to determine the cluster galaxy alignment profile as a function of top-hat scale difference at each redshift. It is shown that the alignment profile of cluster galaxies is well approximated by a power-law of the nonlinear density correlation coefficient that is independent of the power spectrum normalization and bias factor. The alignment profile of cluster galaxies is found to have higher amplitude and lower power-law index when averaged over the larger-mass sample and to have rather weak redshift-dependence. This result is consistent with the picture that the satellite galaxies retain the memory of the external tidal fields right after merging and infalling into the clusters but they gradually lose the initial alignment tendency as the cluster's relaxation proceeds. Demonstrating that the nonlinear density correlation coefficient varies sensitively with the density parameter and neutrino mass fraction, we discuss a potential power of the cluster galaxy alignment profile as an independent probe of cosmology.

• Journal of Korean Clinical Nursing Research
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• v.20 no.1
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• pp.123-133
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• 2014

Purpose: The purpose of the study was to investigate symptom clusters experienced by patients on hemodialysis and to identify relations between symptom clusters and quality of life. Methods: Data were collected from 127 patients at 10 local hemodialysis clinics. Symptoms were measured using 10-item physical symptom checklist as well as the Hospital Anxiety depression Scale. Quality of life was measured with the Satisfaction with Life Scale. Data were analyzed using factor analysis, Pearson correlation, and stepwise multiple regression. Results: The most frequently reported symptoms included fatigue, itching, depression, numbness/tingling, and insomnia. Four distinct symptom clusters were identified: cluster 1 was comprised of dry mouth, headache, nausea (gastrointestinal); cluster 2 of decreased appetite, insomnia (basic need); cluster 3 of itching, numbness/tingling (sensory-comfort); and cluster 4 of fatigue, depression (mood-vitality). Among the clusters, the 'basic need' cluster and 'mood-vitality' cluster had a significant negative association with quality of life. The 'mood-vitality' cluster, explained 17.4% of the variance in quality of life. Conclusion: The results of the study indicate that comprehensive symptom assessment provides better symptom management for patients on hemodialysis. Further studies are needed to verify symptom clusters identified in this study.

• The Journal of Internal Korean Medicine
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• v.44 no.6
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• pp.1197-1211
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• 2023

Objectives: This study presents evidence by analyzing the research trends in acupuncture treatment for cluster headache in the last 10 years. Methods: Randomized controlled trials (RCTs) about acupuncture for cluster headache were searched from the China National Knowledge Infrastructure, PubMed, Cochrane Library, Oriental Medicine Advanced Searching Integrated System, ScienceON, Korean Studies Information Service System, and Research Information Sharing Service. The search terms were the combinations of "cluster headache", "acupuncture", and "needle therapy", and the articles were restricted to those published between 2013 and 2023. Only RCTs were selected. The risk of bias (RoB) was assessed according to the revised Cochrane RoB2 criteria. Results: Six RCTs were selected and analyzed in this review. All selected studies were conducted in China. All RCTs comprised 628 participants. Manual acupuncture was used in all studies. Acupuncture targeting the sphenopalatine ganglion was performed in two papers published after 2020. ST8, Ex-HIN3, and GB14 were the most frequently used acupoints in acupuncture treatment. The most commonly used indicators for evaluation were headache attack frequency, clinical efficacy, and the visual analog scale. In each study, adding acupuncture treatment to conventional therapy had significant effects in relieving the symptoms of cluster headaches. Conclusion: The results suggest that acupuncture is an effective treatment for cluster headache. To ensure objective evidence for the effectiveness of acupuncture treatment in cluster headache, it is important to continue large-scale case reports and RCTs.

• Journal of The Korean Association For Science Education
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• v.25 no.3
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• pp.321-326
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• 2005

The purpose of this study was to identify distinctive achievement goal patterns of students and examine their influence on learning strategies (deep/surface) and science achievement. Cluster analysis procedure was performed to classify students on the basis of task, performance, and performance-avoidance goal scores. The results produced 3 clusters of students with different achievement goal patterns: high task goal (cluster 1), high task-high performance goal (cluster 2), and low task-low performance goal (cluster 3). One-way ANOVA results revealed that the scores of cluster 2 were significantly higher than those of clusters 1 and 3 in deep learning strategy. The science achievement test scores of clusters 1 and 2 were higher than those of cluster 3. Looking at surface learning strategy, however, the test scores of cluster 3 were significantly higher than those of clusters 1 and 2. The educational implications of these findings are discussed.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.2 no.3
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• pp.103-122
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• 2007

Innovation clusters developed or evolved around a specific region IS the key element of national innovation system and determine national competitiveness. Recognizing the importance of innovation clusters, Korean government has made "Daedeok Special R&D Zone" in 2005. This paper examines the success factors of famous Cluster in advanced countries and China, and proposes the strategy for regional development in Daejeon through boosting Daedeok Innovation Cluster. Although 30.5% of government R&D investment is being concentrated in Daedeok along with 10% of the country's doctorate degree holders, it is lack of increasing revenue by linking corporate R&D with a creative and challenging entrepreneur spirit. The core of the innovation cluster is the integration and mutual networking of the main participants. This paper suggests strategies for developing as a world class innovation cluster, global networking and clustering, venture ecosystem formation, commercialization the knowledge by interacting with market. It also explains the necessity of regional integration for cluster to cluster linkages in the East Asia Region.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.203-216
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• 2022

In the recent business environment, purchase patterns are changing around the influence of COVID-19 and the online market. This study analyzed cluster and correlation analysis based on purchase and product information. The cluster analysis of new methods was attempted by creating customer, product, and cross-bonding clusters. The cross-bonding cluster analysis was performed based on the results of each cluster analysis. As a result of the correlation analysis, it was analyzed that more association rules were derived from a cross-bonding cluster, and the overlap rate was less. The cross-bonding cluster was found to be highly efficient. The cross-bonding cluster is the most suitable model for recommending products according to customer needs. The cross-bonding cluster model can save time and provide useful information to consumers. It is expected to bring positive effects such as increasing sales for the company.

• Proceedings of the IEEK Conference
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• summer
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• pp.330-333
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• 2004

Microsensor nodes is energy limited in sensor networks. If nodes had been stop in working, sensor network can't acquire sensing data in that area as well as routing path though the sensor can't be available. So, it's important to maximize the life of network in sensor network. In this paper, we look at communication protocol, which is modified by LEACH(Low-Energy Adaptive Clustering Hierarchy). We extend LEACH's stochastic cluster-head selection algorithm by a Position-based Selection (PB-Leach). This method is that the sink divides the topology into several areas and cluster head is only one in an area. PB-Leach can prevent that the variance of the number of Cluster-Head is large and Cluster-Heads are concentrated in specific area. Simulation results show that PB-Leach performs better than leach by about 100 to $250\%.$

• Journal of Convergence for Information Technology
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• v.10 no.12
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• pp.126-131
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• 2020

This study analyzed the inflow and outflow patterns of emergency department patients, to identify changes in regional types in cities, counties, and districts in Jeonlado, Korea. Data of areas in Jeonlado for 2014 to 2018 were extracted from the National Emergency Department Information System. The extracted data includes the patients' and emergency medical institution addresses, which were used to calculate the relevance index (RI) and commitment index (CI). The calculated indices were classified into regional types by applying cluster analysis. A non-parametric method, Kruskal-Wallis test, was employed to examine the differences between years for RI and CI by regional types. The results of cluster analysis using the relevance and commitment indices revealed three regional types. Regions in cluster 1 were classified as outflow type, in cluster 2 as inflow type, and in cluster 3 as self-sufficient. RI and CI were calculated for each cluster or regional type. There were no significant differences between years in cluster 2 (inflow type) and cluster 3 (self-sufficient type). In cluster 1 (outflow type), there were no significant differences in CI between the years; however, there were significant differences in RI between 2014 and 2017, and 2014 and 2018. It is difficult to see that the emergency medical environment has improved due to the increased concentration of emergency medical care.