• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.332-340
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• 2013

As a means for users to interact online, Social Network Service focuses on facilitating the building of social relation. Also, Social Network Service(SNS) provides various functions for managing relationships and sharing information based on relationships. Analyzing behavioral characteristics and the process of relationship formation can help to identify the characteristics of the model for online human relationship. In this paper, we analyze usage pattern based on characteristics posted messages of influential users in Twitter. Also, classifying Facebook users into influential group and uninfluential group based on the number of their social relations, we analyze and compare characteristics of relationship formation patterns of the two classified groups. In addition, we present characteristics of human relation model in social network according to the pattern analysis.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.285-297
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• 2020

Purpose: This study is a structural model study to grasp the moderating effect of online and offline social support in interpersonal and depressive relationships of nursing students. Methods: This study surveyed 264 nursing students. The collected data is analyzed using Exploratory Factor Analysis, Confirmatory Factor Analysis, and PLS-SEM(Partial Least Square Structural Equation Model) using SPSS 25.0 and Smart PLS 3.0. Results: Interpersonal relationship problems and online social support had a significant effect on increasing depression, and offline social support had a significant effect on reducing depression. In addition, in the relationship between interpersonal problems and depression, only offline social support was found to be significant in the moderating effect. Conclusion: To reduce depression due to interpersonal problems of nursing college students, offline social support should be actively provided, and to investigate the moderating effect of online social support, a repetitive study is proposed that includes relevant variables such as social relationship types through SNS.

• Analytical Science and Technology
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• v.13 no.3
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• pp.297-303
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• 2000

Isotope-dilution inductively coupled plasma mass spectrometry was used to determine trace amounts of Cd, Cu, Pb, Ni and Zn in sediment. Sediment samples were dissolved by microwave digestion with addition of mixed acid ($HNO_3$, HF and $HClO_4$). Lead was determined after separation of alkaline and alkaline earth metals by an ammonium pyrrolidenedithiocarbarmate (APDC) solvent extraction. The other elements were determined after separation of iron, tin and titanium by hydroxide precipitation. Recovery efficiency of the analyte elements was not satisfactory, but most of matrix elements causing the isobaric interference could be effectively eliminated by the separation. Good agreement was achieved with the certified values in the analysis of the two sediment reference materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6547-6555
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• 2014

This study attempted to verify what motivates fans to follow college sports teams' social media and identify the motivational factors that can best predict fans' social media consumption. Confirmatory Factor Analysis (CFA) indicated that previously identified seven motives for online consumption, i.e., information, diversion, socialization, pass-time, fanship, team support, and technical knowledge, are compatible with the use of college sports teams' social media. In addition, a results of multiple regression found diversion, socialization, fanship, team support, and technical knowledge to significantly predict the level of social media consumption while information and pass-time did not significantly affect social media consumption. In particular, socialization had the greatest influence on social media consumption.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.920-924
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• 2007

Two experiments were carried out on a laboratory scale. The first involved a study of the effect of green tea on characteristics of fermented juice of epiphytic lactic acid bacteria (FJLB). FJLB was treated with 50 g/L of green tea products as follows: new shoot powder (FJLB+N), leaf powder (FJLB+L), commercial powder (FJLB+P), sterilized new shoot powder (FJLB+SN), sterilized leaf powder (FJLB+SL) or sterilized commercial powder (FJLB+SP). FJLB without any additive was also prepared (Untreated FJLB). After incubation, the number of microorganisms in FJLB were studied. Subsequently, these FJLB were applied at 10 ml/kg to chopped rhodesgrass to study their effects on fermentation. Compared with untreated FJLB, the addition of green tea increased (p<0.05) lactic acid bacteria (LAB) and also aerobic bacteria counts in FJLB. At 60 d of ensiling, all the FJLB treated silages were well preserved, pH and butyric acid content were lower (p<0.001) and lactic acid was higher (p<0.001) than that of the control. Lactic acid content was significantly higher (p<0.001) with treated FJLB than with untreated FJLB. FJLB treated with sterilized green tea decreased (p<0.001) the pH and the lactic acid content was higher (p<0.001) than that in the unsterilized green tea silages.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1795-1805
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• 2015

This paper analyzed the recommendation stories in the online journalism on the user's news choice by college students in two ways. One way is recommendation stories, and the other one is their arrangement and the index of use. From the results of the analysis, 7 out of 11 types of recommendation stories had positive effects on selecting news stories, while the 4 other types had little effect. Most of the recommendation stories that had little effect on the user's news selection were 'comments' or 'things' related to tweets' on SNS. The arrangements of new stories and the searched keywords had some effects on the user's news choice but had no effect on the index of use. In addition, the hours of using news stories and the types of recommendation stories were mostly correlated with each other. Consequently, formal factors, such as the arrangement of news stories and the recommendation stories of online journalism, had positive effects on the user's news selection, as well as headlines and keywords of news stories.

• Journal of KIISE
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• v.45 no.2
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• pp.165-174
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• 2018

An online community is a virtual group whose members share their interests and hobbies anonymously with nicknames unlike Social Network Services. However, there are malicious user problems such as users who write offensive contents and there may exist data fragmentation problems in which the data of the same user exists in different nicknames. In addition, nicknames are frequently changed in the online community, so it is difficult to identify them. Therefore, in this paper, to remedy these problems we propose a behavior pattern feature vectors for users considering online community characteristics, propose a new implicit behavior pattern called relationship pattern, and identify the nickname of the same user based on Random Forest classifier. Also, Experimental results with the collected real world online community data demonstrate that the proposed behavior pattern and classifier can identify the same users at a meaningful level.

• Journal of Welding and Joining
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• v.33 no.3
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• pp.25-31
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• 2015

Due to environmental regulations (RoHS, WEEE and ELV) of the European Union, electronics and automotive electronics have to eliminate toxic substance from electronic devices and system. Specifically, reliability issue of lead-free solder joint have an increasing demand for the car electronics caused by ELV banning. The authors prepared engine control unit and cabin electronics soldered with Sn-3.0Ag-0.5Cu (SAC305). To compare with the degradation characteristics of solder joint strength, thermal cycling test (TC), power-thermal cycling test (PTC) and series tests were conducted. Series tests were conducted for TC and PTC combined stress test using the same sample in sequence and continuously. TC test was performed at $-40{\sim}125^{\circ}C$ and soak time 10 min for 1000 cycles. PTC test was applied by pulse power and full function conditions during 100 cycles. Combined stress test was tested in accordance with automotive company standard. Solder joint degradation was observed by optical microscopy and environment scanning electron microscopy (ESEM). In addition, to compare with deterioration of bond strength of quad flat package (QFP) and chip components, we have measured lead pull and shear strength. Based on the series test results, consequently, we have validated of series test method for lifetime and reliability of Pb-free solder joint in automotive electronics.

• The Journal of Information Systems
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• v.26 no.4
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• pp.419-442
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• 2017

Purpose The purpose of this study is to explore the pattern of user response and it's duration time through social media content response analysis. We also analyze the characteristics of content quality factors which are associate with the user response pattern. The analysis results will provide some implications to develop strategies and schematic plans for the operator of regional marketing on the SNS. Design/methodology/approach This study used mixed methods to verify the effects and responses of social media contents on the users who have concerns about regional events such as local festival, cultural events, and city tours etc. Big data analysis was conducted with the quantitative data from regional government SNSs. The data was collected through web crawling in order to analyze the social media contents. We especially analyzed the contents duration time and peak level time. This study also analyzed the characteristics of contents quality factors using expert evaluation data on the social media contents. Finally, we verify the relationship between the contents quality factors and user response types by cross correlation analysis. Findings According to the big data analysis, we could find some content life cycle which can be explained through empirical distribution with peak time pattern and left skewed long tail. The user response patterns are dependent on time and contents quality. In addition, this study confirms that the level of quality of social media content is closely relate to user interaction and response pattern. As a result of the contents response pattern analysis, it is necessary to develop high quality contents design strategy and content posting and propagation tactics. The SNS operators need to develop high quality contents using rich-media technology and active response contents that induce opinion leader on the SNS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.514-522
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• 2017

Traffic offloading is a promising solution to solve the explosive growth of mobile traffic. One of offloading schemes, in LIPA/SIPTO(Local IP Access and Selected IP Traffic Offload) offloading, we can offload mobile traffic that can satisfy QoS requirement for application. In addition, it is necessary for traffic offloading using social context due to large traffic from SNS. Thus, we propose the LIPA/SIPTO offloading algorithm using social context. We define the application selection probability using social context, the application popularity. Then, we find the optimal offloading weighting factor to maximize the QoS(Quality of Service) of small cell users in term of effective data rate. Finally, we determine the offloading ratio by this application selection probability and optimal offloading weighting factor. By performance analysis, the effective data rate achievement ratio of the proposed algorithm is similar with the conventional one although the total offloading ratio of the proposed algorithm is about 46 percent of the conventional one.