• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.316-317
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• 2005

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.46-47
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• 2005

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.260-261
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• 2005

• KIPS Transactions on Software and Data Engineering
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• v.8 no.12
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• pp.473-482
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• 2019

There have already been studies analyzing the trajectories of objects from data streams of moving objects. Among those studies, there are also studies to discover groups of objects that move together, called companion groups. Most studies to discover companion groups use existing clustering techniques to find groups of objects close to each other. However, these clustering-based methods are often difficult to find the right companion groups because the number of clusters is unpredictable in advance or the shape or size of clusters is hard to control. In this study, we propose a new method that discovers companion groups based on the distance specified by the user. The proposed method does not apply the existing clustering techniques but periodically determines the groups of objects close to each other, by using a technique that efficiently finds the groups of objects that exist within the user-specified distance. Furthermore, unlike the existing methods that return only companion groups and their trajectories, the proposed method also returns their appearance and disappearance time. Through various experiments, we show that the proposed method can detect companion groups correctly and very efficiently.

• Journal of Digital Convergence
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• v.18 no.8
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• pp.37-48
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• 2020

This study aimed at understanding trends of living lab studies and deriving implications for directions of the studies by utilizing text mining. The study included network analysis and topic modelling based on keywords and abstracts from total 166 thesis published between 2011 and November 2019. Centrality analysis showed that living lab studies had been conducted focusing on keywords like innovation, society, technology, development, user and so on. From the topic modelling, 5 topics such as "regional innovation and user support", "social policy program of government", "smart city platform building", "technology innovation model of company" and "participation in system transformation" were extracted. Since the foundation of KNoLL in 2017, the diversification of living lab study subjects has been made. Quantitative analysis using text mining provides useful results for development of living lab studies.

• The Journal of Society for e-Business Studies
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• v.23 no.4
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• pp.41-62
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• 2018

Despite the rapid growth of the mobile shopping market, major market participants are continuing to suffer operating losses due to severe competition. To solve this problem, the mobile shopping market requires research to improve customer satisfaction and customer loyalty rather than excessive competition. However, the existing studies have limits to reflect the direct needs of customers because they extract the factors on the basis of the Technology Acceptance Model and the literature study. In this study, to reflect the direct requirements of users of mobile shopping Apps, we derived concretely and various factors influencing customer satisfaction through a topic analysis using user reviews. And then we assessed the importance of derived factors to customer satisfaction and analyzed the effects of customer satisfaction on customer complaints and customer loyalty on a structural equation model based on the American customer satisfaction index. We expect that our framework linking a topic analysis and a structural equation model is to be applicable to studies on the customer satisfaction of other mobile services.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.64-70
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• 2016

The recent development of modern weapon system by SOS (System of System) has required users to have more exact decision making. It is possible to achieve the control of complex weapon system more efficiently and effectively by increasing usability. Accordingly, many studies on graphical display have been conducted for several years in the field of HCI (Human Computer Interaction) and GUI (Graphic User Interface), starting from its design stage. Therefore, this paper focuses on evaluating the system GUI usability and analyzing several important points based on performance model, which is a tool for the evaluation and the improvement of service quality. Performance Model, the main focus of this study, reflects user expectations (which is defined as user importance in this paper). The study consists of four steps. First, 34 checklists are drawn from the existing studies related to GUI usability evaluation by using a heuristic method, and then the checklists are matched with 11 weapon system design factors. Next, the study evaluates the importance of GUI element and the usability of weapon system "A" with the checklists twice respectively. Third, the performance of user importance ($P_i$) and the performance of usability ($P_u$) are calculated by modifying a numerical formula for normalization in this step. Finally, the study compares the approach it takes and the existing usability evaluation method, demonstrating that there is a significant difference between the two methods as a result. In addition, 4 improvement factors are suggested for weapon system "A" as "Shortcut" and "Description of Abbreviation," and so on. Although it is necessary to conduct more studies for higher reliability and validity of the results, this study is meaningful considering it takes a new point of view.

• Asia pacific journal of information systems
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• v.23 no.3
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• pp.77-104
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• 2013

Mobile technology is accelerating innovative changes across all fields of our society as well as business environments. Especially, demands on mobile government (M-government) services have been increased gradually since e-government has improved national administration services dramatically. However, high-quality services which are acceptable to may users are not actually supplied because technical issues such as security on mobile e-government services have not solved and governance policy was not established yet. Previous studies show that most researches are devoted to technical ones or limited to theoretical exploratory study. As a result, developing useful guidelines which are practically and theoretically proved is one of the very important research issues. This study reviews the previous research works such as concept of mobile, e-government, M-government, technical trends of mobile, market situations, present status, and various case studies. And then we develop a research model with five factors, twenty four variables and seventy six measurement for measuring the influencing factors to adoption of M-government services. The model is composed of total 16 hypotheses, 22 variables, and 76 measurements. The model is analyzed by using statistical package SPSS (18.0) and AMOS (18.0) together with structural equation method based on 294 samples. The results show that the model is valid and there are statistically significant influence between ease of use and usefulness, ease of use and user's satisfactions, usefulness and intent of re-use, and user's satisfactions and intent of re-use, excepting usefulness and user's satisfaction, ease of use and intent of re-use did not affect significant influences. Especially, service quality, system quality, and relationship quality are identified as influencing factors to adaption of M-government service. The results are expected to provide a theoretical research framework which generate new research issues in M-government service area. It also can provide an useful guidelines to practical experts in successfully implementing M-government services. Further research directions are as follows. User's intents have to be studied in details by classifying users by individual, enterprise, and government as well as developing a new hypothetical model. Since M-government service is at the initial stage, longitudinal studies have to be conducted to trace the peoples' need in order to develop new high-quality mobile services.

• The Journal of Society for e-Business Studies
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• v.18 no.2
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• pp.257-277
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• 2013

Those studies in the field of Management Information Systems and the Success Model of the DeLone and McLean's Information Systems suggest that some factors related to information systems should be developed and operated to affect the performance of the user's personal and companies through the introduction and use of corporate information systems. The purpose of this study is put on searching for some factors which impact on user satisfaction about the customer information management systems of call center. We did conduct on a survey of 539 people who are working as a call center counseling employees as setting up a structural equation model which reflects previous research on working environment and job satisfaction, and modified DeLone and McLean's information system success model. The results of this study are as follows. First, seven of the eleven hypotheses that three quality of the information systems might be affecting working environment, job satisfaction, user satisfaction were adopted Second, we confirmed that the working environment works as a the partial mediation and the quality of services works as a fully mediation between system/information quality and users' satisfaction. The implications of this study are that it is necessary not only to make a good working environment but also to keep improving it in order to boost the operational performance of information systems in the future.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.567-581
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• 2014

Recently, with the introduction of social network services, studies that try to make use of them for the various purposes have been actively developed. In order to proceed with the research that takes advantage of social network services, it is necessary to review the relevant literature and to identify trends in researches. However, the researches of social network service since 2007 are massive amount, so to review the huge amount of relevant research literature is a very difficult task. Therefore, in this study, we analyze systematically the tendency of research related to social network service focusing on Twitter. Especially, we use the SLR(Systematic Literature Review) technique for systematic literature survey and analysis. For the literature survey, we select five well-known literature resource sites and 128 studies of literature that are surveyed. In order to identify various research trends, we conduct the survey with two research groups: researches since 2007 and researches since 2011. As a result of the investigation, since 2007, the researches associated with "Application", "User Activity" and "User Content Analysis" main study topics have been mostly carried out. In addition to the result, the trend of secondary study topics in a main study topic, trends in research based on the number of citations and the scale of the experimental data and characteristics of the author are analyzed from a variety of perspectives.