• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1113-1121
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• 2010

The Vehicle Safety Communications (VSC) is one of VANET applications for preventing vehicle accidents, and it utilizes vehicle-to-vehicle communication to exchange emergency messages. To propagate such messages in VSC, several schemes based on selective flooding have been proposed. Their common idea is that an emergency message is relayed by one of vehicles receiving the message. However, the schemes do not consider the transmission errors and duplications of an emergency event. In the schemes, if there are transmission errors and a vehicle detects a hazard, there may be vehicles which fail to receive an emergency message. If k vehicles detect a hazard, k emergency messages are created and propagated. The duplications of an event increase reliability of the message delivery but decrease efficiency. In this paper, we propose an emergency message delivery scheme which is efficient and robust to transmission errors. Our proposed scheme utilizes clustering for massage aggregation and retransmissions in a cluster. It also uses an acknowledgment mechanism for reliable inter-cluster communication. Our simulation results show that the proposed scheme outperforms Least Common Neighbor Flooding which is one of the selective flooding schemes.

• Journal of the Korean Geographical Society
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• v.48 no.5
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• pp.768-785
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• 2013

Count data aggregated into areal units such as administrative boundaries are the most important sources of information for geographic research. Despite of ongoing research on spatial cluster analysis of count data, it has received relatively little attention and besides, it is difficult to comprehend research trends as well as major outcomes and challenges. This study aims to review the research literature conducted during the last two decades, to examine methodological characteristics, and finally to discuss some issues and challenges. Methods for indentifying spatial clusters have been used in various fields including geography, criminology, and epidemiology. However, their methodological features are not only quite distinct from each other, but there are issues related to the statistical reliability. Therefore, these have to be taken into account carefully when particular methods are used, and further empirical research about methodological issues and the development of analysis tools is needed.

• Journal of Korean Academy of Nursing Administration
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• v.9 no.3
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• pp.415-427
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• 2003

Purpose: The purpose of this study was to investigate the degree and pattern of knowledge management process, and to identify the relationship between knowledge management process and organizational effectiveness in clinical nurses. Method: Participants were 665 regular clinical nurses who had worked for over 1 year in general units of 9 tertiary medical hospitals including 2 national university hospitals, 5 university hospitals, and 2 hospitals founded by business enterprises. Data were collected from March to May 2003 through questionnaires. Four structured instruments were used to collect the data: Knowledge Management Process Scale(Jeong, Lee, Lee, & Kim, 2003), cCommitment Questionnaire(Mowday, Steers, & Porter, 1979), General Satisfaction Scale(CooK, Hepworth, Wall, & Warr, 1981), and one for general characteristics. The data were analyzed using factor analysis, reliability analysis, descriptive analysis, cluster analysis, one-way ANOVA, Scheffe test, correlation analysis with the SPSS for Windows 10.0 program. Result: 1) The average score for knowledge management process in nurses was $3.08{\pm}.54$ on a 5-point Likert scale. In order from highest mean score, the elements of knowledge management process, were Knowledge $Utilization(3.35{\pm}.57)$, Knowledge $Sharing(3.07{\pm}.58)$, Knowledge $Creation(2.99{\pm}.63)$, and Knowledge $Storage(2.91{\pm}.82)$. 2) Four knowledge management patterns for nurses, which were derived from cluster analysis, were inactivate pattern, delayed pattern, activate pattern, and high-activate pattern of knowledge management. 3) The degree of knowledge management process activation and 4 elements of knowledge management process, Knowledge Creation, Knowledge Storage, Knowledge Sharing, and Knowledge Utilization, were significantly correlated with nurses' organizational commitment and job satisfaction(p=.000). 4) The nurses' organizational commitment and job satisfaction showed significant differences according to the knowledge management patterns derived from cluster analysis of high-activate pattern, activate pattern, delayed pattern, inactivate pattern(p=.000). Conclusion: These results suggest that there are four knowledge management patterns for nurses, and knowledge management process positively affects the nurses' organizational commitment and job satisfaction. From the above findings, knowledge management process is empirically verified as a useful and effective method to increase organizational effectiveness, and develop the organization.

• The KIPS Transactions:PartA
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• v.12A no.2 s.92
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• pp.151-160
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• 2005

The exponential growth of Web users requires the web serves with high expandability and reliability. It leads to the excessive transmission traffic and system overload problems. To solve these problems, cluster systems are widely studied. In conventional cluster systems, when the request size is large owing to such types as multimedia and CGI, the particular server load and response time tend to increase even if the overall loads are distributed evenly. In this paper, a cluster system is proposed where each Web server in the system has different contents and loads are distributed efficiently using the Web server resource information such as CPU, memory and disk utilization. Web servers having different contents are mutually connected and managed with a network file system to maintain information consistency required to support resource information updates, deletions, and additions. Load unbalance among contents group owing to distribution of contents can be alleviated by reassignment of Web servers. Using a simulation method, we showed that our method shows up to $50\%$ about average throughput and processing time improvement comparing to systems using each LC method and RR method.

• The Journal of Information Systems
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• v.28 no.2
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• pp.53-72
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• 2019

Purpose The purpose of this study is to examine the impact of tie strength in the network of industrial clustering on the knowledge acquisition, integration and innovation performance of small and medium sized enterprises. We test the positive relationship of weak tie and knowledge acquisition, strong tie and knowledge integration, and the interaction effect of two tie strengths on both processes of knowledge acquisition and integration. By identifying these relationships, we can better understand how to manage the attributes of social networks in terms of tie strength in order to improve the performance of innovation for the small and medium sized enterprises. Design/methodology/approach We collect 200 survey data from 2 industrial cluster respectively: Pankyo and Guroo. In Pankyo, the proportion of IT industry is the highest (35%) while the proportion of manufacturing is highest (35%) in Guroo. Pooling the data from two industrial cluster, we check the reliability and validity of our research model and test the hypotheses. Findings First, we find the positive relationship of weak tie and knowledge acquisition from both industrial clustering. Weak tie is composed of heterogeneous organizations with various background and expertise. The communication and information sharing of organizations in the weak tie network helps the idea generation for organization's innovation, which is the knowledge acquisition process. Second, the relationship of strong tie and knowledge integration is insignificant. Typically the strong tie from long-lasting partnership is expected to be beneficial in the action stage of innovation, which is the knowledge integration process. However it is not identified in our industry cluster. Finally, the interaction effect of weak and strong tie is identified to be effective on both knowledge acquisition and integration processes.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.5 no.3
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• pp.47-68
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• 2010

In this study, a unit of regional tourism as a cluster of innovative strategies that can be an assumption that the activation of tourism clusters building on local festivals and participated to review the empirical aims. The purpose of this study was to achieve literature and empirical research were given recognition for the cultural festival in Chungnam, Chungcheong-do you want to go to the local cultural festival linked to the tourist attractions, the cluster characteristics, participation motives, the festival satisfaction, revisit the decision, recommendation of the The analysis was carried out degrees. To this end, local cultural festivals and attractions, Chungnam 150 spectators in the survey was conducted, the statistical analysis using SAS 9 statistical package program was analyzed. Used for statistical analysis, frequency analysis, factor analysis, reliability analysis, multiple regression analysis. Festival of the cluster attribute satisfaction and revisit four on the most direct impact on the competitive conditions were not. Festival in regard to motivation and satisfaction with intrinsic motivation, extrinsic motivation in returning to the doctor more were affected. The condition is the element intrinsic motivation, extrinsic motivation is a race condition was the biggest influence. Therefore, the element condition Satisfaction Festival, a race condition in four to revisit the biggest indirect impact can be seen.

• Journal of the Korea Society of Computer and Information
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• v.26 no.11
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• pp.1-9
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• 2021

3D-NAND flash memory provides high capacity per unit area by stacking 2D-NAND cells having a planar structure. However, due to the nature of the lamination process, there is a problem that the frequency of error occurrence may vary depending on each layer or physical cell location. This phenomenon becomes more pronounced as the number of write/erase(P/E) operations of the flash memory increases. Most flash-based storage devices such as SSDs use ECC for error correction. Since this method provides a fixed strength of data protection for all flash memory pages, it has limitations in 3D NAND flash memory, where the error rate varies depending on the physical location. Therefore, in this paper, pages and layers with different error rates are classified into clusters through the K-means machine learning algorithm, and differentiated data protection strength is applied to each cluster. We classify pages and layers based on the number of errors measured after endurance test, where the error rate varies significantly for each page and layer, and add parity data to stripes for areas vulnerable to errors to provides differentiate data protection strength. We show the possibility that this differentiated data protection policy can contribute to the improvement of reliability and lifespan of 3D NAND flash memory compared to the protection techniques using RAID-like or ECC alone.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.42-48
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• 2015

Generally, the current commercial cloud system is hosted by the centralization large datacenter. However, the other clouding forms existed and one of them is the P2P cloud. The P2P Cloud is a distributed systems, is freedom to join and leave and is possible to provide the IaaS. Commonly, P2P Cloud System is based on Pure-P2P System. Since a number of connection paths exist, it has a high reliability and easily scalability of the network. However, there are disadvantages of the slow rate of route because of looking up the all peers in order to search for the peer. In this paper, it proposes the P2P cloud system based on super-peer P2P. Super-peer P2P system has fast routing time, because of searching for cluster unit and it also can has high reliability and high scalability. We designs the super Peer cloud service and proposes the system model and Resource Allocation Algorithm for IaaS in Super peer P2P environment.

• Human Ecology Research
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• v.53 no.6
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• pp.655-665
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• 2015

This study classified respondents by food-lifestyle and investigated differences in diet-related attitudes and demographic variables among food-lifestyle groups. Diet-related attitudes consisted of variables such as interest in diet, trial number of diet, diet period, weight loss, diet motivation, verification of products approved by the Ministry of Food and Drug Safety, verification of manufacturer's reliability, examination of damage cases and side effects, and awareness of consumer protection law. This study administered a questionnaire survey to adults between the ages of 20 and 39 who lived in Daegu and Uijeongbu from November 17th to December 14th 2014. Data collected from 293 respondents were analyzed using descriptive statistics, factor analyses, cluster analysis, analysis of variance (ANOVA) and chi-square tests. Four clusters (passive eating habit group, active eating habit group, convenience oriented group, and taste and health oriented group) were developed according to four factors of food-lifestyle (health-conscious, popularity-seeking, taste-seeking, convenience-seeking). The results of the ANOVA and chi-square tests indicated significant differences in interest in diet, awareness of consumer protection law, verification of products approved by the Ministry of Food and Drug Safety, verification of manufacturer's reliability, examination of damage cases and side effects, gender, education levels and household monthly income levels among food-lifestyle groups.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.94-102
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• 2023

The purpose of this study is to identify the effects of leisure sports participants' leisure attitudes on immersion and fun perception. As of 2021, the subject of this study was set as a population of adult males and females aged 20 and over who participate in leisure sports in Gwangju and the South, and then the cluster random sampling method was used. A total of 300 people, 150 boys and 150 women, were collected. A questionnaire was used as a survey tool, and a questionnaire whose validity and reliability were recognized in previous studies was modified and secured according to this study. In addition, all questionnaires were constructed on a 5-point scale. The statistical analysis used for data analysis was frequency analysis, exploratory factor analysis, reliability analysis, and multiple regression analysis using SPSS Windows 21.0 Version. The conclusions obtained in this study through data analysis by such methods and procedures are as follows. First, it was found that leisure sports participants' leisure attitudes partially affect immersion. Second, leisure sports participants' leisure attitudes were found to have a partial effect on their perception of fun. Third, it was found that the immersion of leisure sports participants partially affects the perception of fun.