• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.58
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• pp.38-49
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• 2006

In order to increase the spectrum efficiency, recently, there is the number of studies for CR technology. For instance, IEEE 802.22 WRAN(Wireless Regional Area Network) WG considered the CR technology as a solution of WRAN system to serve the high speed internet service(1.5 Mbps down stream and 384 kbps up stream) in 100 km overall coverage and 54 MHz-746 MHz band. Basically, in MAC point of view, the WRAN system have been standardizing based on the IEEE 802.16 MAC layer features such as Data transmission method, QoS provision and Bandwidth request schemes. Additionally, the WRAN system further include CR nature functions such as incumbent user protection, self coexistence which would be importantly considered. Also, the inherent WRAN functions are added such as channel bonding and fractional bandwidth usage. This paper mainly explained frame structure, IU protection, self coexistence which are key functions of WRAN system. Finally, in this paper, we expressed a prospect of IEEE 802.22 WRAN standardization.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.303-311
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• 2022

Recently the telemedicine platform firms which have been temporarily permitted since COVID-19 outbreak have increasingly provided online prescription drugs delivery, causing concerns among incumbent providers of medicine, some of whom began to take aggressive actions again them. In this study, using game theoretic market entry - deterrence model, we show that although the incumbent medicine provider can effectively deter entry by the telemedicine platform firms by its preemptive action, accommodation could be a optimal action when telemedicine platform firms already have penetrated the market with their being permitted to do business due to the COVID-19. However, for the incumbent to cooperate for the successful change in the retail market for medicines, policies like placing a ceiling on the maximum number of taking prescriptions by the pharmacists a day in the telemedince platform network, providing favorable exposure of community pharmacists on the telemedicine platform user interface, and allowing community pharmacies to participate as shareholders of the telemedicine platform firms in its initial public opening of capital, are suggested.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.32 no.3
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• pp.145-162
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• 2021

To identify key job duties and core competencies of data librarians, this study conducted content analyses of 75 U.S. job advertisements of data librarians and statistical analyses of 105 responses from incumbent data librarians. As a result, the key job duties identified are jobs related to collaboration, workshops, trainings, conferences, data service, research consultation, and research support. Core competencies identified are communication skills, teaching, diversity, inclusion, and equality, data management, and data tool. This study is significant in that it analyzed the key duties and core competencies of the data librarians using the most up-to-date data and opinions collected from incumbent people. It can be a basis for future study such as on job satisfaction, user satisfaction, and perception surveys for data librarians.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1074-1081
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• 2021

It has recently been noticed that the headway of unlicensed wireless technology is necessary as user's demands of wireless tech increase and the development of high-speed data service by using low-power short-range wireless network is needed. Hence, it is inevitable to study sharing and coexistence for broadband spectrum of diverse unlicensed application with wide bandwidth. In this paper, an interference examination between unlicensed WiFi (Wireless Fidelity) in the 6GHz and OB (Outside Broadcasting) system which is an incumbent service in the same frequency band was conducted and it suggests separation distance for the coexistence. Thus, MCL (Minimum Coupling Loss) and MC (Monte Carlo) methods were used to set up interference scenarios for the interference analysis and compute the separation distance between two systems according to the same frequency band and frequency separation.

• Journal of Information Technology Services
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• v.15 no.1
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• pp.81-96
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• 2016

This study analyzes how breach fee under long-term contract and/or cap regulation on the breach fee can affect the impacts of "Mobile Device Distribution Improvement Act" on handset bundle price, average revenue per unit (ARPU), and social welfare. We conduct comparative analysis with an economic model of duopoly competition in price when users are under long-term contract and the breach fee can be regulated. The results show that the Act lowers the equilibrium prices, lower than incumbent price without the Act. Price of non-dominant Mobile Network Operator (MNO) can be lower than poaching price without the Act if significant portion of switching cost is breach fee or the market is significantly asymmetric. Under the significant circumstances, the Act can raise ARPU even though it improves social welfare. By contrast, the Act increases consumer surplus without affecting social welfare if breach fee is the only source of user's switching cost and is capped by the regulation, and more symmetric market and the stronger cap leads to higher consumer surplus.

• Journal of the Korean Society for information Management
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• v.32 no.3
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• pp.261-276
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• 2015

The aim of this study is supporting efficient development of library collection and improvement of library service for users by analyzing utilization patterns of library collection using circulation statistics of medical library users. With this purpose, circulation statistics were extracted from 90,420 cases of circulation records in A library for recent 3 years (from 2012 to 2014). Specifically, circulation data categorized according to status and subject, loan data of most popular books and use data of inter-library loan service were collected and analyzed. Subject groups of this study are undergraduate students, graduate students and incumbent hospital employees including faculty members, training members and nondoctor members. For the result, medical library users intensively lent materials of Technology (Applied Sciences), Literature and Social science areas. Especially, the demand of the materials of literature was higher than the demand of the other subject areas compared in the base of collection development.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.8-14
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• 2008

There are two a approaches for the Cognitive Radio(CR) development. One is 'Full CR', which Joseph Mitola III proposed, and another is 'Spectrum CR', which is currently being standardized. The target approach of this paper is the latter and we develop a Cognitive Engine(CE) and simulated a channel set management(CSM), which is a core function of CE. The Channel set management evaluates channel quality and Incumbent User(IU) vacancy possibility and classifies the channel set, which is performed by using channel state history. Especially, a very important function for the channel set management is a channel state prediction and this paper proposed a Hidden Markov Model(HMM) based channel state prediction and a method for increasing performance. Also, we applied the proposed method into our simulator and simulated channel state prediction. Through the simulation, we verified as we applied our proposed scheme, the performance of channel state prediction gets better and through comparing with RS and SS, we verified the HMM based Channel state prediction is better.

• Journal of Korea Technology Innovation Society
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• v.11 no.2
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• pp.145-170
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• 2008

The existence of network is indeed the single most important factor that brings about new business phenomena in the new digital economy, especially in the IT industry. Network effect refers to a phenomenon that the increase in size of the network leads to increased network value and user utility. It determines the competitive structure of an industry and the performances of industry competitors (Shapiro and Varian, 1999). The phenomenon of increasing returns and winner-take-all enjoyed by the early winner in the competition can be attributed to the existence of positive feedback which increases the value of network and induces more users into join the network (Arthur, 1996; Shapiro and Varian, 1999; Song and Lee, 2003). This research attempts to shed light on the topic of innovation and competitive strategy of network-based industries. We analyze the case of the Korean mobile communications industry, in which a shift in technological paradigm from 2G to 3G brought new changes to the competitive structure of the industry. The Korean mobile communications industry makes an ideal case for analysis since it is an industry whose value is inherently dependent upon its user network. It is characterized by the typical increasing returns, in which a monopolizing player is enjoying firstmover's network effects. Because of the existence of network in the mobile communications industry, latecomers' disruptive innovations could not outcompete the incumbent's sustaining innovations. The contribution of this research lies in laying a groundwork for future studies by introducing a numerical simulation model to analyze the complexity theory and network effect.