• ETRI Journal
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• v.26 no.6
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• pp.665-668
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• 2004

The introduction of a mobile virtual network operator (MVNO) system is expected to increase consumer benefits, boost competition in the mobile market, utilize idle bandwidth, and expedite mobile-fixed line convergence and growth in the mobile Internet market. This research endeavors to study the optimal access charge for an MVNO system, which is expected to be introduced to the Korean mobile communications market. We found that the optimal access charge is higher in the interdependent model than in the independent model if demand for mobile phone service is based on a substitution relationship. We also found that the optimal access charge is higher than the marginal cost.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.48-49
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• 2013

In this paper, the four switches three-phase Z-source rectifier is studied. The conventional three-phase four switches rectifier can only either perform buck or boost operation, distortion and unbalance of the input current are serious. Therefore, we proposed the four switches three-phase Z-source rectifier which can realize buck function simply by applying the Z-impedance network. We will verify characteristics of Z-network by the simulation and experiment.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.534-541
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• 2004

To boost the Korean peninsula as a logistical hub of North-East Asia in 21st century is an important part of Korean development strategies. This research has been conducted on the premise that the connection and operation of the Korean Peninsula break-railway and Euro-Asian railway network will be a great drive for Korean economy and railway technology development. For the preparation to do a further research on this subject, this paper introduces the general condition and related basic material for the railway network operation through the countries along the corridor. It also provides the basic data of railway and actual operation condition in the involved Euro- Asian areas, such as Russia, China, Mongolia, Kazakh-stan, etc.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.220-221
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• 2016

This paper proposes an active switched-capacitor embedded quasi-Z-source inverter (ASC-EqZSI) topology. In order to improve boost ability, One diode and one switch device are added in the qZSI impedance network, and a single dc source is shifted in series with the inductor in the impedance network. The performances of the proposed topology are verified with simulation and experimental results.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.256-274
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• 2022

The continuous information technology and telecommunication (ICT) developments inspire several Saudi Arabia citizens to transact and interact online. However, when using online platforms, several people are likely to lose their personal information to cybercriminals. In the survey, 553 Saudi Arabia citizens and 103 information technology (IT) specialists confirm the expansion of digital economy and the need for smart cities with various services, including e-commerce and solid cyber security. 96.6% of the participants believe Saudi Arabia is digitalizing its economy; yet, 33.3% of the participants believe that residents are uninformed about living and operating in smart cities. Several people (47.29%) with medium internet speed are more aware about smart cities than those with fastest internet speed (34%). Besides, online transactions via credit cards subjected 55.5% of the participants to privacy and security issues. These findings validate the essence of cyber security awareness programs among Saudi Arabia citizens and IT professionals to boost public trust and acceptance of cybersecurity frameworks.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.143-148
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• 2022

Component-based software development (CBD) is a methodology that has been embraced by the software industry to accelerate development, save costs and timelines, minimize testing requirements, and boost quality and output. Compared to the conventional software development approach, this led to the system's development being completed more quickly. By choosing components, identifying systems, and evaluating those systems, CBSE contributes significantly to the software development process. The objective of CBSE is to codify and standardize all disciplines that support CBD-related operations. Analysis of the comparison between component-based and scripting technologies reveals that, in terms of qualitative performance, component-based technologies scale more effectively. Further study and application of CBSE are directly related to the CBD approach's success. This paper explores the introductory concepts and comparative analysis related to component-based software engineering which have been around for a while, but proper adaption of CBSE are still lacking issues are also focused.

• International Journal of Computer Science & Network Security
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• v.22 no.11
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• pp.357-366
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• 2022

Artificial intelligence (AI) is the replication of human intelligence by computer systems and machines using tools like machine learning, deep learning, expert systems, and natural language processing. AI can be applied in administrative settings to automate repetitive processes, analyze and forecast data, foster social communication skills among staff, reduce costs, and boost overall operational effectiveness. In order to understand how AI is being used for administrative duties in various organizations, this paper gives a critical dialogue on the topic and proposed a framework for using artificial intelligence in organizations. Additionally, it offers a list of specifications, attributes, and requirements that organizations planning to use AI should consider.

• Journal of information and communication convergence engineering
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• v.22 no.2
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• pp.133-138
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• 2024

Dissolved oxygen (DO) is an important factor in ecosystems. However, the analysis of DO is frequently rather complicated because of the nonlinear phenomenon of the river system. Therefore, a convenient model-free algorithm for DO variable is required. In this study, a data-driven algorithm for predicting DO was developed by combining XGBoost and an artificial neural network (ANN), called ANN-XGB. To train the model, two years of ecosystem data were collected in Anyang, Seoul using the Troll 9500 model. One advantage of the proposed algorithm is its ability to capture abrupt changes in climate-related features that arise from sudden events. Moreover, our algorithm can provide a feature importance analysis owing to the use of XGBoost. The results obtained using the ANN-XGB algorithm were compared with those obtained using the ANN algorithm in the Results Section. The predictions made by ANN-XGB were mostly in closer agreement with the measured DO values in the river than those made by the ANN.

• Journal of the Korea Society of Computer and Information
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• v.20 no.7
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• pp.77-84
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• 2015

The study is to investigate which features are perceived by Social Network Service(SNS) users as the most required one to further boost the usage of service, and to examine the perception of these features of SNS sites varies according to their demographic and service usage characteristics. The study also is to suggest a few of research propositions on the relationships between required features of SNS sites and characteristics of SNS users, based on statistical analyses. To accomplish these research purposes, the study defined characteristics of SNS users including demographic(gender, age) and service usage one(start time of service usage, service usage place), and required features of SNS sites(system, service, information, emotion) based on the literature review of SNS. The results show, based on the statistical analyses using survey questionnaire on Korean and Chinese SNS users, that there are differences in perception of required features of SNS sites among the respondents grouped by age, start time of service usage, service usage place. Finally, the study proposed three research propositions, based on the analysis result, that could be used in SNS related researches in the future.

• The Journal of Korean Association of Computer Education
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• v.14 no.5
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• pp.71-79
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• 2011

We designed and implemented a cooperative learning system using social network service which can be utilized on a smart phone for users to read each other's posting once they upload posting and to give feedback concerning the posting in real time without the need for accessing a relevant website, through the installation of a necessary application which makes it possible for learners to interact at any time in any place on a smart phone. The developed program is used as an intermediate tool for real-time communications so as to aid in solving the task of learners, and it was made to boost academic achievement as well as interest in learning through real-time interactions and feedback. Furthermore, the program was designed in such a way that an instructor actually helps learners by closely identifying their levels based on accumulated data.