• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.13-21
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• 2018

The system of systems (SoS) based analysis method for the C3 system consisting of the communication system and the command and control (C2) system has the advantage that detailed analysis is possible, but it requires long execution time per one trial, which makes the analysis of various scenarios difficult. To solve this problem, this paper proposes a method for analysis of C3 SoS using a transformation of a federation into an integrated simulation. This transformation technique reduces the execution time while maintaining accuracy by abstracting the system other than the one to be analyzed, consisting of model hypothesis and function identification. The former can construct an abstracted model for the simulation through the proposed extended Discrete Event Systems Specification (DEVS) formalism and the latter can express the characteristics of the model influenced by other systems. From the case study on C and C2 analysis, the experimental results show that this method shortened the time considerably while maintaining the accuracy within an acceptable error range and we expect that this method will enable the exploratory analysis of the complex systems other than C3.

• The Journal of the Petrological Society of Korea
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• v.25 no.2
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• pp.143-149
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• 2016

Eruptive volumes of three monogenetic volcanoes (Songaksan tuff ring, Biyangdo scoria cone, and Ilchulbong tuff cone) with the youngest eruption age are calculated using the model, applied to Auckland Volcanic Field in New Zealand, to investigate the volcanic eruption scale and to evaluate volcanic hazard of Jeju Island. Calculated eruptive volumes of the volcanoes are $24,987,557m^3$, $9,652,025m^3$, and $11,911,534m^3$, respectively, and the volumes include crater infill, tuff ring (tuff cone), scoria cone, and lava flow. Volcanic explosivity indices of Songaksan tuff ring, Biyangdo scoria cone, and Ilchulbong tuff cone are estimated based on the eruptive volumes to be 3, 2, and 3 respectively, and eruption type is Strombolian to Surtseyan. It is assumed that the amount of emitted sulfur dioxide gas is $2-8{\times}10^3kt/y$ according to the correlation between volcanic explosivity index and volcanic sulfur dioxide index. Recent age dating researches reveal evidences of several volcanic activities during the last 10,000 years indicating the possible volcanic eruption in Jeju Island in the near future. Therefore, it is necessary for appropriate researches regarding volcanic eruption of the island to be accomplished. In addition, establishment of the evaluation and preparation system for volcanic hazard based on the researches is required.

• Informatization Policy
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• v.18 no.3
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• pp.50-68
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• 2011

In this paper, our goal is to examine the factors related to smartphone users' usage addiction. Based on existing literature on mobile usage behavior and addiction, we developed and tested a theoretical model and hypotheses, analyzing how variables based on the characteristics of smartphones affect smartphone usage addiction and how smartphone usage addiction affects social withdrawal. Given the literature review, a questionnaire survey was conducted; and the PLS(Partial Least Square), a kind of SEM(Structural Equation Model), was used to analyze and test the research model and hypotheses. The research results indicated that smartphone users' self-monitoring, loneliness, and smartphone characteristics affect users' usage addiction. Further, smartphone users' usage addiction affects their social withdrawal. Finally, theoretical and practical implications of these findings and directions for future research were discussed.

• Information Systems Review
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• v.14 no.3
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• pp.99-114
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• 2012

In July 2010, The Korean government announced a plan to implement smart work centers to resolve low birth rate, low productivity and social costs of the urban traffic jams. The Plan calls for up to 30 percent of the working population to be working under the smart work system by 2015. This empirical study was conducted to find factors affecting the Smart Work Center use. Based on the IS Success Model, 'operation Infra Quality' and 'User Satisfaction' have positive impact on the Smart Work Center use. 'System Infra Quality' and 'IT Infra Quality' have positive impact on the 'User Satisfaction'. Consequently 'System Infra Quality' and 'IT Infra Quality' have positive impact on the Smart Work Center use indirectly.

• Smart Media Journal
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• v.12 no.9
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• pp.89-94
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• 2023

Recommender systems provide users with the most favorable items by analyzing explicit or implicit feedback of users on items. Recently, as the size of deep-learning-based models employed in recommender systems has increased, many studies have focused on reducing inference time while maintaining high recommendation accuracy. As one of them, a study on recommender systems with a knowledge distillation (KD) technique is actively conducted. By KD, a small-sized model (i.e., student) is trained through knowledge extracted from a large-sized model (i.e., teacher), and then the trained student is used as a recommendation model. Existing studies on KD for recommender systems have been mainly performed only for implicit feedback settings. Thus, in this paper, we try to investigate the performance and accuracy when applied to explicit feedback settings. To this end, we leveraged a total of five state-of-the-art KD methods and three real-world datasets for recommender systems.

• Journal of Information Management
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• v.33 no.1
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• pp.48-60
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• 2002

According to the rapid increasement of web usage, an appropriate model which supports systematically the web-based application-to-application interactions and the approach which can integrate the new distributed computing platform and the existing environments have been investigated. The web services has emerged as the solution to these needs. This paper describes the background of the emergence of the web services and the definition and characteristics of web services. Then, after explaining the operation mechanism of web services, the core techniques which are essential to implement the web services and the implementation cases are examined. Lastly, the future of web services has been mentioned.

• Journal of Information Technology Applications and Management
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• v.17 no.1
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• pp.55-81
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• 2010

ASP service users' needs for flexible and customized services to deal with changes in business environments and user contexts seems to be appealing due to the progress of technology and IT paradigm such as ubiquitous computing and web 2.0. Through the lens of expectancy confirmation and flexibility, we explored factors that influence users' repurchase intent and organizational benefit in ASP services. With an empirical study, we examined information quality, service quality, flexibility, customization, user satisfaction, trust in ASP services can contribute to the repurchase intent and organizational benefit. In addition to, business type and company size are added to the research model as control variables for user satisfaction, trust, and repurchase intent. Our findings suggested that the service quality and flexibility significantly were cruicial determinant of user satisfaction in ASP services. Furthermore, user satisfaction significantly influenceS repurchase intent, and organization benefits were affected by repurchase intent. This study has important implications for academic researchers and practitioners who seek to understand factors that affect ASP service users' repurchase intent and organization benefits.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.3
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• pp.83-97
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• 2020

Unlike the feature of SNS, which strengthens two-way communication and promotes interaction through consistent on/off line identity management, passive use of Facebook to unilaterally accept other people's opinions is being strengthened, and more people tend to use Facebook anonymously or pseudonym to enjoy freedom of expression. To illustrate this transformative use behavior, this study suggests an integrated model including psychological and behavioral variables such as self-esteem, real name use, and opinion expression to explore the effect on social relationship value perception and satisfaction. Studies have shown that self-esteem affects the use of real names and self-exposure, and that the satisfaction and sustainability of relationships have increased as real-name users expose more information about themselves.

• Journal of Broadcast Engineering
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• v.21 no.5
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• pp.782-791
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• 2016

The object segmentation algorithm from the background could be used for object recognition and tracking, and many applications. To segment objects, this paper proposes a method that refer to several initial frames with real-time processing at fixed camera. First we suggest the probability model to segment object and background and we enhance the performance of algorithm analyzing the color consistency and focus characteristic of camera for several initial frames. We compensate the segmentation result by using human skeleton characteristic among extracted objects. Last the proposed method has the applicability for various mobile application as we minimize computing complexity for real-time video processing.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.3
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• pp.1-7
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• 1996

The stress concentration factor gives the significant effect the fatigue strength of welded joints. The model used herein is the type of the load carrying fillet welded cruciform joint with full or partial penetration. In order to obtain the stress concentration factor at the weld toe of fillet joint, the reasonable element size of the toe part is investigated and the stress analysis for the series models by FEM under tensile load is performed. On the basis of the calculation results, the estimated formulae for the stress concentration factor(Kt) at weld toe part of the fillet welded joint, which the effect of toe radius, flank angle and other parameters are taken into account, is derived.