• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권7호
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• pp.1777-1791
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• 2012

This paper considers a downlink cognitive radio (CR) network where one secondary user (SU) and one primary user (PU) share the same base station (BS). The spectrum of interest is divided into a set of independent, orthogonal subchannels. The communication of the PU is of high priority and the quality of service (QoS) is guaranteed by the minimum rate constraint. On the other hand, the communication of the SU is of low priority and the SU opportunistically accesses the subchannels that were previously discarded by the PU during power allocation. The BS assigns fractions ?? and 1 ?? of the total available transmit power to the PU and the SU respectively. Two power allocation schemes with opportunistic subchannel access are proposed, in which the optimal values of ??'s are also obtained. The objective of one scheme is to maximize the rate of the SU, and the objective of the other scheme is to maximize the sum rate of the SU and the PU, both under the PU minimum rate constraint and the total transmit power constraint. Extensive simulation results are obtained to verify the effectiveness of the proposed schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.3249-3257
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• 2015

The smart convergence environment, in which all industries are converged around ICT infrastructure -- with the eventual inclusion of both industry and culture -- looms. With the emergence of new convergence industries such as smart medicine, smart cities, and smart automobiles, the ICT infrastructure is recognized as the foundation of the overall economy. As such, the importance of the next generation of information and communication construction businesses, which constructs the ICT infrastructure, is highlighted under the smart convergence paradigm environment; various multilateral policies to foster the information and communication construction business -- led by the Ministry of Science, ICT, and Future Planning -- are being implemented. Like other infrastructure industries, however, the estimation of the demand function of the information and communication construction business overall is essential for effectively establishing promotional policies for information and communication construction businesses. However, there has been no study which theoretically estimates the market demand function in the information and communication construction business thus far. The pursuit of a creative economy is a national agenda, as the significance of accelerating the ICT infrastructure is emphasized. Therefore, this paper seeks to estimate quantitatively the demand function in the information and communication construction business using empirical data and a statistical model and then to present policy implications which will aid the development of the information and communication construction business.

• 한국정보컨버전스학회:학술대회논문집
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• 한국정보컨버전스학회 2008년도 International conference on information convergence
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• pp.181-184
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• 2008

This work was supported by the MIC(Ministry of Information and Communication), Korea, under the ITRC(Information Technology Research Center) support program supervised by the IITA(Institute of Information Technology Assessment) and Yonsei University Institute of TMS Information Technology, a Brain Korea 21 program, Korea. CAD Tools were supported by IDEC.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권2호
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• pp.524-539
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• 2014

To investigate schemes of secret key generation from Ultra-wideband (UWB) channel, we study a statistical characterization of UWB outdoor channel for a campus playground scenario based on extensive measurements. Moreover, an efficient secret key generation mechanism exploiting multipath relative delay is developed, and verification of this algorithm is conducted in UWB Line-of-sight (LOS) outdoor channels. For the first time, we compare key-mismatch probability of UWB indoor and outdoor environments. Simulation results demonstrate that the number of multipath proportionally affects key generation rate and key-mismatch probability. In comparison to the conventional method using received signal strength (RSS) as a common random source, our mechanism achieves better performance in terms of common secret bit generation. Simultaneously, security analysis indicates that the proposed scheme can still guarantee security even in the sparse outdoor physical environment free of many reflectors.

• Journal of Communications and Networks
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• 제13권6호
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• pp.664-677
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• 2011

In order to control interference and improve spectrum efficiency in the femtocell and macrocell overlaid system (FMOS), we propose a joint frequency bandwidth dynamic division, clustering and power control algorithm (JFCPA) for orthogonal-frequency-division-multiple access-based downlink FMOS. The overall system bandwidth is divided into three bands, and the macro-cellular coverage is divided into two areas according to the intensity of the interference from the macro base station to the femtocells, which are dynamically determined by using the JFCPA. A cluster is taken as the unit for frequency reuse among femtocells. We map the problem of clustering to the MAX k-CUT problem with the aim of eliminating the inter-femtocell collision interference, which is solved by a graph-based heuristic algorithm. Frequency bandwidth sharing or splitting between the femtocell tier and the macrocell tier is determined by a step-migration-algorithm-based power control. Simulations conducted to demonstrate the effectiveness of our proposed algorithm showed the frequency-reuse probability of the FMOS reuse band above 97.6% and at least 70% of the frequency bandwidth available for the macrocell tier, which means that the co-tier and the cross-tier interference were effectively controlled. Thus, high spectrum efficiency was achieved. The simulation results also clarified that the planning of frequency resource allocation in FMOS should take into account both the spatial density of femtocells and the interference suffered by them. Statistical results from our simulations also provide guidelines for actual FMOS planning.

• Journal of Multimedia Information System
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• 제1권1호
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• pp.67-75
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• 2014

Nowadays as video services grow rapidly, it is important for the service providers to provide customized services. Video ranking plays a key role for the service providers to attract the subscribers. In this paper we propose a weekly video ranking mechanism based on the quantified user engagement. The traditional QoE ranking mechanism is relatively subjective and usually is accomplished by grading, while QoS is relatively objective and is accomplished by analyzing the quality metrics. The goal of this paper is to establish a ranking mechanism which combines the both advantages of QoS and QoE according to the third-party data collection platform. We use data mining method to classify and analyze the collected data. In order to apply into the actual situation, we first group the videos and then use the regression tree and the decision tree (CART) to narrow down the number of them to a reasonable scale. After that we introduce the analytic hierarchy process (AHP) model and use Elo rating system to improve the fairness of our system. Questionnaire results verify that the proposed solution not only simplifies the computation but also increases the credibility of the system.

• 한국정보시스템학회지:정보시스템연구
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• 제16권3호
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• pp.91-108
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• 2007

To decide a reasonable investment priority of public enterprises, it is required to have an efficient evaluation standard. However, without having a standard, a budget for those enterprises has been allocated. In this research, for the efficient and reasonable budget allocation, it is discussed how to decide investment priority of information and communication enterprises of the government. In order to examine possible alternatives of the investment priority of information and communication enterprises of the government, seventeen enterprises were chosen from the enterprises of Ministry of Information and Communication. Public benefit, economic benefit, technology, politics, and step-up increase of budget were set up as evaluation standards and 16 specific standards were set up as subordinates. A hierarchical decision model was designed and analyzed by using AHP.

• 한국통신학회논문지
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• 제4권1호
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• pp.8-24
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• 1979

Including the Qualfication of Staffer required for Commuinication, the National Law of Professional qualification is a basic law for supply with manpower of high growth industry, and it is aiming at perfect the national Policy Concerned improvement for education and training of staff, carrying out of state examination for qualification and getting an occupation or application for special qualification. This law has established a management committee for qualification system in The Ministry of Science and Technique ROK, and authorized competence Minister according to kind of special qualification aiming at getting employment, practical use and courteous treatment in society and economy for national qualification, and also regulated their each official duty. A qualification of staffer required for communication is an administrative measure giving as occupational certificate after some examination for knowledge, technique and faculty in vocational ability to adapt to intrinsic of telecommunication. This certificate has the cause of an attribution of over the sphere of telecommunication, and so it has been originated in international situation, and then some of them is forced by international law, otherwise it be in common use between the nations. The Characteristic and orthodox of communication certificate has been succeded continually in company with development of telecommunication and the appliable field of them is specified, but the sovereign power of nation is approved by ITU that she can extent the applicable position for communication certificate and coordinate the utility of qualification for telecommunication value. Korean telecommunication law excepted the application of communication certificate in public communication field. It is unreasonable and even disobeyed against the theory of communication science and intrinsic of telecommuncation. Therefore it should be corrected immediately and then communication certificate have to accept in the public communication field at all, if so, the application field of communication certificate can have more than useful extenxion such as administration measure should be achieved by the management committee for qualification system in Ministry of Science and Technique and competemce Minister appointed according to special kind of certificate and the administration have to manage by the method and proccess caused by communication science or cooperative system between administration, industry, education and science. And, then, every acquisitor of qualification also has to try to perfect his vocational duty sincerely and to promote each self-realization.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3018-3036
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• 2013

In this paper, we investigate power allocation scheme and outage performance for a physical-layer network coding (PNC) relay based secondary user (SU) communication in cognitive multi-antenna relay networks (CMRNs), in which two secondary transceivers exchange their information via a multi-antenna relay using PNC protocol. We propose an optimal energy-efficient power allocation (OE-PA) scheme to minimize total energy consumption per bit under the sum rate constraint and interference power threshold (IPT) constraints. A closed-form solution for optimal allocation of transmit power among the SU nodes, as well as the outage probability of the cognitive relay system, are then derived analytically and confirmed by numerical results. Numerical simulations demonstrate the PNC protocol has superiority in energy efficiency performance over conventional direct transmission protocol and Four-Time-Slot (4TS) Decode-and-Forward (DF) relay protocol, and the proposed system has the optimal outage performance when the relay is located at the center of two secondary transceivers.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.850-853
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• 2002

This paper described some applications using Open GIS Component that was called MapBase. There were 4 applications : KSDI(Korea Spatial Data Infrastructure) funded by MOIC(Ministry of Information and Communication), National Plants Resource Management System supported by Korea Forest Service, 7-Underground Facilities Management System of Cheongju funded by MOCT(Ministry of Construction and Transportation), and National Disaster Management System supported by MOGAHA(Ministry of Government Administration and Home Affairs. Because they wanted to access heterogeneous spatial database, it was necessary to select MapBase as their base methodology. The main feature of MapBase was component S/W which provided the interoperability and reusability among GIS applications as well as non-GIS information system through common specification. In this paper, we showed some applications' architectures and functions to increase understanding MapBase. That would help you to make application using MapBase.