• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.1-9
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• 2015

Recently, cognitive radio technology has been spotlighted for the efficient use of limited frequency technology. The most important part of CR is to protect the incumbent user's communications. Therefore, CR user should be sensing the currently using channel and another hopping channel for sudden appearance of the Incumbent User. In this paper, we propose the cooperative channel sensing to protect the IU considering each CR user's remained power and sensing-zone, sense the spectrum bands in a fairly distributed manner and share the results among the users within respective sensing zone. Sensing scheme including inband sensing and outband sensing is utilized. The inband sensing is in charge of current using channel scanning while the outband sensing mainly cares about other channels. The performance results by computer simulations show that our sensing scheduling scheme reduces the number of sensing nodes and saves energy need to channel sensing.

• 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 Korean Institute of Communications and Information Sciences
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• v.33 no.7B
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• pp.538-549
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• 2008

Recently IEEE 802.22 WG has considered Cognitive Radio (CR) technology to overcome shortage of communication channels. For using CR technology, accurate and rapid sensing method selection is extremely important. According to the channel sensing method, it is of the utmost importance because it can affect the incumbent system protection. So, optimum selection of channel sensing method is very important. IEEE 802.22 gives the solution, name of fine sensing, but the solution can not adapt to various networks. So in this paper we propose Policy-based Channel Sensing Architecture and Algorithms for Cognitive Radio Networks. The proposed channel sensing architecture and algorithms can reduce both primary system detection time and quiet time in our simulation. Among the proposed sensing algorithm, channel division round robin sensing reduce average detection time up to 70% compare to fine sensing method in IEEE 802.22.

• STI Policy Review
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• v.7 no.2
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• pp.60-84
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• 2016

What impact does the sharing economy have on existing businesses? This paper empirically examines how Uber transformed the taxi industry in New York City. Using a regression model controlling various potential influencing factors, we find no direct evidence that daily trips or revenue per taxi driver decreased since Uber entered the taxi industry. However, a closer investigation into other dimensions of taxi trips reveals that taxi drivers were forced to change their way of doing businesses to retain existing daily trips and revenue. Since Uber crowded out yellow taxis from the central area of Manhattan, yellow taxis responded by serving customers outside of the Manhattan borough. From enlarging their geographical coverage and serving customers that were previously ignored, yellow taxis were able to retain their previous level of taxi trips and market share. We also find that yellow taxis responded by improving their service quality to better serve customers' needs. Our result suggests that incumbents actively responded to Uber's entry and provided substantial benefit to consumers. Combined with the incumbent's response, the sharing economy transformed the existing market in a welfare-enhancing way. This paper provides managerial and policy implication on how incumbents affected by the disruptions of the sharing economy should respond. Even though it might be yet premature to examine the impact of Uber, results suggest that incumbents have effectively defended against Uber's entry so far. We conclude that the sharing economy and the existing economy can create positive value in our society through well-intentioned competition, complementing each other's weaknesses and strengths.

• Korean journal of communication and information
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• v.59
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• pp.162-179
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• 2012

The purpose of this study is to find a way to revive newspaper industry against digital new media revolution such as the internet, SNS(Social Network Service). To this end, indepth-interviews were conducted with the target incumbent senior reporters. The research areas are consisted of four subjects. For instance Awareness about the newspaper business crisis, the need for profitable business, potential conflicts of journalism and business, and desirable business. As a result of my research, executive reporters said that There is no management strategy Against the rapid expansion of social media and Therefore Business diversification is required. In short, They said that alternative business model should be developed, in which public and business interest are commonly respected, such as Information & Culture (internet, broadcasting, film, game, music), play, exhibition, publishing, and education.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2030-2038
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• 2009

We analyze the economic effects of mobile termination rate asymmetry by simulation model. The asymmetry allows the mobile operator to get access profits at the expense of the incumbent and induces negative effects such as the entry of inefficient operator and allocative efficiency as well as productive efficiency. We use simulation model to investigate the effect on social welfare of asymmetric regulation. If the brand loyalty is high, social welfare increase as the termination charge of entrant increases. The extension of the basic model shows that the degree of social welfare increase becomes higher as the brand loyalty increases when the cost of entrant is smaller than that of incumbent. But, the degree of social welfare decrease becomes lower as the substitution effects increase.

• Journal of Gifted/Talented Education
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• v.9 no.1
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• pp.63-84
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• 1999

This study is to examine the current problems of teaching gifted children and suggest elements(or factors) to be considered in setting up goals thereof by analyzing incumbent teachers awareness. 121 teachers were arbitrarily selected from 30 different kindergartens located in Seoul and Anyang, and they were interviewed with two parts questionnaires(or opinions) of improving current practice. The first part of the questionnaire is composed of the questions about teachers awareness of gifted children, actual state of teaching gifted children, effects of teaching in kindergarten for gifted children, and desired direction for teaching improvement. The second part of the questionnaire provided interpretation of precociousness by study habit, creativity and definitive properties and asked the number of children qualified in their classes. Since the results of the first interview as to awareness of gifted children were dismal, 40 teachers were thereafter randomly selected again, and the second interview was warranted. The results alarmingly revealed that program of teaching gifted children were barely existing even though the teachers awareness for the needs of special education for the precocious as well of study materials and programs thereof was high. In addition, the teachers familiarity of gifted children was surprisingly low. At the second interview whereby gifted children was explained, the teachers awareness of gifted children was dramatically improved to 40% in comparing with 7.4% at the first interview without explanation of gifted children. Teachers awareness of gifted children was low because of lacking direct or indirect experience of having gifted children and special programs therof in their classes as well as teachers nonchalance. Therefore not only adequate training and education of teachers, but also cultivation of qualified teachers for special programs for the precocious are obligatory. Training of incumbent teachers and determination of gifted children are prerequisite for timely discovery of gifted children and adequate education for them. Development of special education programs and diffusion are also crucial.

• 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 Digital Convergence
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• v.19 no.7
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• pp.95-111
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• 2021

Despite the innovation of AI and Big Data, theoretical research bout the effect of AI and Big Data on market competition is still in early stages; therefore, this paper analyzes the effect of AI, Big Data, and data sharing on an entry firm by using game theory. In detail, the firms' business environments are divided into internal and external ones. Then, AI algorithms are divided into algorithms for (1) customer marketing, (2) cost reduction without automation, and (3) cost reduction with automation. Big Data is also divided into external and internal data. this study shows that the sharing of external data does not affect the incumbent firm's algorithms for consumer marketing while lessening the entry firm's entry barrier. Improving the incumbent firm's algorithms for cost reduction (with and without automation) and external data can be an entry barrier for the entry firm. These findings can be helpful (1) to analyze the effect of AI, Big Data, and data sharing on market structure, market competition, and firm behaviors and (2) to design policy for AI and Big Data.

• 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.