• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.4224-4243
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• 2021

Cognitive radio (CR) is a feasible intelligent technology and can be used as an effective solution to spectrum scarcity and underutilization. As the key function of CR, cooperative spectrum sensing (CSS) is able to effectively prevent the harmful interference with primary users (PUs) and identify the available spectrum resources by exploiting the spatial diversity of multiple secondary users (SUs). However, the open nature of the cognitive radio networks (CRNs) framework makes CSS face many security threats, such as, the malicious user (MU) launches Byzantine attack to undermine CRNs. For this aim, we make an in-depth analysis of the motive and purpose from the MU's perspective in the interweave CR system, aiming to provide the future guideline for defense strategies. First, we formulate a dynamic Byzantine attack model by analyzing Byzantine behaviors in the process of CSS. On the basis of this, we further make an investigation on the condition of making the fusion center (FC) blind when the fusion rule is unknown for the MU. Moreover, the throughput and interference to the primary network are taken into consideration to evaluate the impact of Byzantine attack on the interweave CR system, and then analyze the optimal strategy of Byzantine attack when the fusion rule is known. Finally, theoretical proofs and simulation results verify the correctness and effectiveness of analyses about the impact of Byzantine attack strategy on the throughput and interference.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.8
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• pp.2507-2528
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• 2022

Blockchain interoperability, which refers in particular to the ability to access information across blockchain systems, plays the key role for different blockchains to communicate with each other, and further supports the superstructure built on top of the cross-chain mechanism. Nowadays, blockchain interoperability technology is still in its infancy. The existing cross-chain scheme such as BTCRelay requires that the smart contract in a blockchain to download and maintain block headers of the other blockchain, which is costly in maintenance and inefficient to use. In this paper, we propose a supervision mechanism between blockchains, called Surveillant. Specially, the new entities called dual-functional nodes are introduced to commit the real-time information from the blockchain under supervision to the supervising blockchain, which enables users to have efficient cross-chain verification. Furthermore, we introduce Merkle mountain range for blocks aggregation to deal with the large-scale committing data. We propose the design of long orphan branch counter to trace the bifurcations in the blockchain under supervision. The existing incentive mechanism is improved to encourage the behaviors of dual-functional nodes. In Surveillant, the analysis and experimental results demonstrate that users are able to have efficient cross-chain verification with low maintenance overhead.

• Journal of the HCI Society of Korea
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• v.12 no.2
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• pp.5-12
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• 2017

The forms of emoticon - a symbolic tool which expresses a person's sentiments and emotions in virtual space - have been diversifying by the growth of the mobile market. In light of this phenomenon, a number of studies about emoticon have been conducting in Korea. Nevertheless, those are limited not only to a certain form of emoticon which is combinations of symbolic characters but to the functional aspect of emoticon. Thus, this research focused on the image-form emoticon which is the most highly used, and on the user's perspective rather than functional. It is (1)found out the motive of using image-form of emoticon, and (2)explored the attitude and using behaviors toward emoticon based on the motives found. Moreover, this study (3)examined if there is a gender effect and intimacy effect. As a result, the motives of the emoticon-users were to express their emotions, to show their intimacies to the receivers, to manage their images, and to supplement text-based messaging. Two of the motives - expressing emotions and expressing intimacy - had a positive effect on the attitude and the frequency of emoticon-use. It is also found that the higher intimacy users feel toward the receivers, the better the attitude they have as well as the more frequent they use emoticon. This study suggests practical implications of emoticon as a growing communication tool by identifying the motives of using it. And it also contributes to examine the effect of the motives and intimacy on the attitude and the actual behavior of using emoticon.

• Journal of Korean Academy of Nursing
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• v.30 no.1
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• pp.7-17
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• 2000

The purpose of this study is to affect health improvement of adolescent, to understand behavioral causes follow adolescent's drug abuse, to understand recovery and rehabilitaton process of adolescent drug abuser. The data are collected through open questionnaire and interview of 25 adolescents from the experienced drug abuse 16 students(male 8, female 8) in two vocational high schools and admissing adolescents 9 person in Alcohol-Drug Addiction Care Centre in Seoul from June 28th to August 31st, 1994. The collected data are arranged and explained through categorizing method stated contents about motives, causes, experiences and effected behaviors for using the drugs of drug abuser adolescents. DRUG USING MOTIVATION They are almost first son and daughter in their family. In their conversation person, male converses to their mother well, but female does not converse to their parents include family. Both groups respond positively to companionship and attitude to other, but negatively to self-confidence and actualizing attitude. They hope always peace of family and want to do their best for their life. In school group, hard and difficult things are school life and family problems, also using the drugs for resolving the them. About drug using behaviors, male responds to bad habbit and shamfull, but female is unconcerned with drug using attitude. The first background of drug using, male gets to use because of curiosity and to be induced from friends or seniors, but female gets to use for feminine beauty(thin body) and escape from reality. Used the drugs, male uses frequently Bond, Butane-Gas among inhalation materials and also marijuana, but female uses various diuretics. The times of drug using, both groups repond to use during the chaging of emotion or filling with stress. The place of drug using, both groups take drugs in vacant houses or in the mountain. The frequency of drug using, they use almost once in a day and they use mostly alone or drug user in friends. Experienced mental changing after drug using, which is fantasy, ecstasy, anxiety and suicidal feeling, and experienced physical changing after drug using, which is elevating sense, headach, abdominal pain, dyspnea and chaging of skin colour and reddish. They coincide with inconvenience feeling due to drug using. RECOVERY AND REHABILITATION PROCESS OF DRUG USING ADOLESCENTS The reason for reforming drug using behavior and attitude, both groups respond to reforming for oneself and social life. The difficult things during the stop to using drugs, all of them responed to family problems, friends problems and temptation and impulse. As for stop to using drug, they need good advise, understandable attitude and family love. But they do not need to be stigmatized, scolding, over protect and ridicule of friends. Also they entreat continuous understanding, advise, concern and the method for resolving stress. For the friends to want to use the drug, they will talk about the stories of their personal experiences and for the friends to stop to using the drug, they will consider for them how to stop. From the theses results, drug users understand personal problems due to drug using, and consider about why to stop and how to stop. Also drug users need to resolve the family problems, personal problems, stress and temptations or impulses. Accordingly this paper suggests that drug users in adolescents need understandable and acceptable atitudes, loving and tenderness, continuous advice and concern, and hopes for life.

• Journal of Distribution Science
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• v.14 no.9
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• pp.85-94
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• 2016

Purpose - Recently, Mobile technologies and devices including smart phones and tablets have increased the possibility of communicating with other people and sharing personal information without time and space restriction. In order to realize the market potential related to mobile technologies, a large number of internet services have been incorporated into mobile platforms. Especially, The number of MIM(Mobile Instant Messenger) users has been increasing dramatically and services using MIM platform also have diversified. In spite of drastic growth in markets related to MIM, there is little empirical research on MIM and users' behaviors. This study designed to examine the structural relationships among belongingness, loneliness, self-disclosure intention, system quality, and self-disclosure behavior in context of MIM. Research design, data, and methodology - Three hypotheses were about the relationship among belongingness, loneliness and self-disclosure intention. The other two hypotheses were about the moderating effect of system quality in the causal relationship between self-disclosure intention and self-disclosure behavior. The data was analyzed by structural equation modeling. Research data were obtained from 330 undergraduate students who were KakaoTalk users and total 314 valid questionnaires were used in the final analysis. Results - The results from this study are as follow. First, the belongingness and the loneliness had a significant impact on self-disclosure intention in MIM. Second, the self-disclosure intention in MIM also had a positive impact on the self-disclosure behavior. Lastly, there is a moderating effect of the system quality in the relationship between the self-disclosure intention and self-disclosure behavior in MIM. Specifically, the higher system quality level was perceived, the positive effect of the self-disclosure intention in MIM on the self-disclosure behavior was greater. Conclusions - Based on the results from this study, academic and practical implications can be drawn. First, the study extends the scope of research about SNS through focusing on MIM to be classified by closed type SNS and identifies the relationship between emotion, behavioral intention and behaviors in MIM. Second, this study provides strategic guidelines to increase the efficiency for promotion activity. Limitations for the study also should be discussed.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.169-180
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• 2017

China's mobile communication market has been growing quantitatively and qualitatively since 2000. Currently, it has secured 1.27 billion mobile subscribers and many of the Korean companies try to enter the Chinese market and cooperation with companies in China is being held. Thus understanding of the Chinese markets is the key to better prepare for future international competition. This study is to identify factors affecting switching intentions and behaviors for Chinese mobile subscribers to other mobile service providers by the PPM and it is to derive correlations between strategies of mobile service providers and users' switching intention by the groups classified by ARPU. We conducted a survey targeting 270 Chinese mobile users and analyze it by using Smart PLS 2.0. In conclusion, push effects have positive influence on intention to switching and relational switching cost among mooring effect have significantly negative influence on intention to switching In particular, intention to switching depending on the groups classified by a level of their ARPU have been shown as significantly different. This study will extend theoretical range of PPM theory in explaining users' switching behaviors and contribute to establish strategies to enter the chinese market.

• Journal of Digital Convergence
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• v.19 no.11
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• pp.181-199
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• 2021

Recently, financial companies are promoting chatbot services in line with the reduction of branches and the expansion of non-face-to-face services. However, it is difficult to expand the chatbot services at once in the presence of technical limitations and constraints of internal and external environment. Therefore, it is necessary to analyze the various situations of chatbot service to preemptively identify problems that can occur in stages and seek solutions. This study conducted interviews with 12 field practitioners and researchers to examine the intentions and behaviors of financial chatbot service users and interpreted them using TPB. The study revealed the characteristics of 'feelings and attitudes' such as convenience or inconvenience from the chatbot experience, 'subjective norms' such as herd behavior or the yearning for empathy of others, and 'behavioral control' according to the recognition of difficulty or convenience of chatbot use process. This study shows that this characteristic can affect the intention and actual behavior of users to use chatbot service continuously. In the future research, it is necessary to empirically study specific intentions and influence factors for actual users.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.1
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• pp.11-19
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• 2004

Such social structures as bridges,, buildings, dams and towers have been transformed by their own load or fundamental ground. They have been behaved by other external causes. These regular or irregular behaviors threaten to do their users safety. Therefore, to monitor the load of the structures or reaction shown by them could help to verify their behaviors. RTK GPS allows the use of a static base station and remote rover unit to allow f3r data collection within several seconds and in real time. It is useful for monitoring the behaviors of massive structures like bridges. In this Study, Among GPS methods, we used RTK GPS to analyze the precision of monitoring and then on the basis of it, we developed a monitoring system using RTK GPS when measured the behavior of main tower of a suspension bridge by using RTK GPS. Comparing a deviation between observation values, X axis was Imm, Y axis was 1mm and Z axis 2.2mm. It turned out that it was possible to monitor and measure structures by RTK GPS.

• Journal of the Korean Society for information Management
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• v.21 no.4 s.54
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• pp.265-279
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• 2004

This study is to research quintessence of information service in the libraries by interpreting 'Information' as it is ubiquitous. For the purpose, it investigates and analyzes information behaviors of the libraries in information-cultural history. The meaning of 'ubiquitous' is understood as a practice that everything we need should be inherent in our lives for its usefulness and effectiveness. Information is intrinsic in our lives and the libraries, information management systems, have been evolved by extending the intrinsic value of information, 'ubiquity'. Human being's history results from information behaviors and the meaning of the libraries consists of production, accumulation, organization and distribution of the libraries. It should be recognized that the ultimate purpose of the library services is for their users. Consequently information systems and technological networks in the libraries should be focused on applications and inherence for the purpose. Model studies of the libraries should be developed to user-centered information services that substantialize the interpretation of information, as it is ubiquitous. This study is a trial for defining the quintessence of the libraries. Furthermore, it provides foundation of understanding what the libraries are.

• Journal of the Korean Society for information Management
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• v.26 no.2
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• pp.65-82
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• 2009

This exploratory study describes the social bookmarking perceptions and behaviors of students in university courses. Although an emerging discussion regarding the value of social bookmarking tools exists, how users adopt tools in practice is not well known. Students were asked to utilize the bookmarking tool del.icio.us to store information relating to course projects. They were also asked to comment how they employed del.icio.us for course projects. The study analyzed student perceptions and behaviors when using social bookmarking tools for university coursework. The study noted that the use of tags, notes, and networking within these social bookmarking tools remained less active and social bookmarking services in Web 2.0 as shared collaboration, shared communities, and vertical search were less present. Utilizing social bookmarking tools to facilitate personal information management includes the activities of information use, information re-use, and mobility.