• Journal of Communications and Networks
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• v.16 no.2
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• pp.183-192
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• 2014

This paper proposes a payment-based power control scheme using non-cooperative game with a novel pricing function in cognitive radio networks (CRNs). The proposed algorithm considers the fairness of power control among second users (SUs) where the value of per SU' signal to noise ratio (SINR) or distance between SU and SU station is used as reference for punishment price setting. Due to the effect of uncertainty fading environment, the system is unable to get the link gain coefficient to control SUs' transmission power accurately, so the quality of service (QoS) requirements of SUs may not be guaranteed, and the existence of Nash equilibrium (NE) is not ensured. Therefore, an alternative iterative scheme with sliding model is presented for the non-cooperative power control game algorithm. Simulation results show that the pricing policy using SUs' SINR as price punishment reference can improve total throughput, ensure fairness and reduce total transmission power in CRNs.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1039-1040
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• 2006

The resonant converters cause the high voltage stress according to the input voltage, which increases the conduction loss in converter power switches. The topology of LLC half bridge resonant converter provides ZVS characteristic and also the stress of voltage and current is not higher than that of the general resonant converters. So we can expect the higher efficiency. In this paper, the LLC resonant converter is designed for the notebook computer adapter. In the adapter design, we should consider the weight, the size and overheat of the adapter. Thus the higher efficiency is an essential particular. First of all, the optimal design of transformer is the most important facts. Some parameters should be considered in order to get the highest efficiency. The adapter is designed through the considering of these parameters including the PFC circuit of the pre-regulator. It converts AC line input into about $400V_{DC}$ Link voltage of the LLC converter input and the converter has $16V_{DC}/90W$ ratings. The efficiency measured is about up to 92%.

• Composites Research
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• v.16 no.6
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• pp.1-9
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• 2003

In this paper, probabilistic failure analysis based on Weibull distribution function is proposed to predict the fiber strength of composite pressure vessel. And, experimental tests were performed using fiber strand specimens, unidirectional laminate specimens and composite pressure vessels to confirm the volumetric size effect on the fiber strength. As an analytical method, the Weibull weakest link model and the sequential multi-step failure model are considered and mutually compared. The volumetric size effect shows the clearly observed tendency towards fiber strength degradation with increasing stressed volume. Good agreement of fiber strength distribution was shown between test data and predicted results for unidirectional laminate and hoop ply in pressure vessel. The site effect on fiber strength depends on material and processing factors, the reduction of fiber strength due to the stressed volume shows different values according to the variation of material and processing conditions.

• English Language & Literature Teaching
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• v.16 no.3
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• pp.317-337
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• 2010

The present study has a dual purpose to investigate the current state of school English library and needs required for its effective use, and to propose a reading program at the school library. The literature on school library was reviewed. A questionnaire survey was done to find out the current situation of English library at the secondary school. The analysis of 26 secondary English teachers' responses reveals that there was the absence of librarians or reading specialists at the school English library. It was also found that the uses of the English library were limited due to the absence of the specialists, no guidelines, and no link between the curriculum and the library use. A case study on a 2-week special reading program at the school English library was conducted and 15 middle school students took part in the project. The participants took pre- and post-tests to identify their reading level using a software and did a variety of reading activities using the books selected according to their level. The comparison of the tests shows that most of the students' reading level improved after the reading program. The analysis of their views on the program and its effects reveals that they gained confidence in reading and their vocabulary understanding was improved. Some suggestions are made for the effective management of the school English library.

• Journal of Communications and Networks
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• v.16 no.4
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• pp.371-377
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• 2014

Localized topology control is attractive for obtaining reduced network graphs with desirable features such as sparser connectivity and reduced transmit powers. In this paper, we focus on studying how to prolong network lifetime in the context of localized topology control for wireless multi-hop networks. For this purpose, we propose an energy efficient localized topology control algorithm. In our algorithm, each node is required to maintain its one-hop neighborhood topology. In order to achieve long network lifetime, we introduce a new metric for characterizing the energy criticality status of each link in the network. Each node independently builds a local energy-efficient spanning tree for finding a reduced neighbor set while maximally avoiding using energy-critical links in its neighborhood for the local spanning tree construction. We present the detailed design description of our algorithm. The computational complexity of the proposed algorithm is deduced to be O(mlog n), where m and n represent the number of links and nodes in a node's one-hop neighborhood, respectively. Simulation results show that our algorithm significantly outperforms existing work in terms of network lifetime.

• Journal of the Korean Solar Energy Society
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• v.27 no.1
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• pp.19-27
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• 2007

The Data quality management system(DQMS) organizes and helps manage and process time sequence data usually collected in monitoring networks and programs. DQMS places particular emphasis on data qualify while maintaining a highly organized and convenient structure for data. It operates with in a flexible and powerful commercial relational data base environment which can readily link to other software platforms from local spreadsheets to network server. The Korea Institute of Energy Research(KIER) has been solar radiation data since May, 1991 for 16 different locations. KIER's new data is expected to be extensively used by designer and researchers of solar systems in lieu of unreliable old ones. Unfortunately, the quality of the data has not always been properly mentioned. The purpose of this study is to systematically identify errors in such data set using DQMS in an effort to rehabilitate error-ridden old data. DET successfully uncovered solar radiation data that had questionable quality.

• STI Policy Review
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• v.7 no.2
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• pp.16-34
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• 2016

This study aims to identify the chronological trajectory of university science parks (USPs) in China and to discuss the roles of government-driven science and technology (S&T) policies in the development of USPs and the future directions of these entities. Our study shows that USPs in China have undergone two development waves: The first from the late 1980s to the late 1990s, when research universities expected to directly participate in economic activities, and the second from 2000 when the Ministry of Science and Technology (MOST) and the Ministry of Education (MOE) jointly enacted the Proposed Regulation of State-level USPs Management to guide and regulate the development of USPs. The development trajectory highlights that USPs are effective platforms that link scientific research, knowledge spillovers and industrial system. However, Chinese USPs still need to confront some conundrums which may influence the processes and outcomes of UILs. Finally, we also summarize the major issues inherent in the development of USPs to guide policymakers to enact more effective policies.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.9-16
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• 2004

For a System-on-a-Chip(SoC) comprised of multiple IP cores, test control techniques have been developed to perform the internal and external test efficiently relying on the various design for testability techniques such as scan and BIST(Built-In Self-Test). However the test area overhead is too expensive to guarantee diverse test link configurations. In this paper, at first we introduce a new flag based Wrapped Core Linking Module(WCLM) that enables systematic integration of IEEE 1149.1 TAP'd cores and P1500 wrapped cores. Then a simple test control technique, which can interconnect internal scan chains of different cores, is described with requiring least amount of area overhead compared with other state-of-art techniques. The design preserves compatibility with standards and scalability for hierarchical access.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.1
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• pp.115-123
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• 2010

The purpose of this study was to examine the effect of Busan Ocean Industry Expo on ocean related industries and Busan regional economy. The study analyzed the effects of the various projects related to Busan Ocean Industry Expo and answered the question of how to link the effects to development of ocean related industries as well as the economic activation of Busan area. To attain this goal, first of all, this study attempted to analyze status of ocean related industries, characteristics of existing exposition and opinion of enterprises. To maximize the above positive effects of Busan Ocean Industry Expo, several strategic alternatives were suggested.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1108-1110
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• 2007

The resonant converters cause the high voltage stress according to the input voltage, which increases the conduction loss in converter power switches. The topology of LLC half bridge resonant converter provides ZVS characteristic and also the stress of voltage and current is smaller than that of the general resonant converters. So we can expect the higher efficiency. In this paper, the LLC resonant converter is designed for slim adapter. In the adapter design, we should consider the weight, the size and overheat of the adapter. Thus the optimal design of transformer is the most important facts. Some parameters should be considered in order to get the highest efficiency. The LLC resonant converter input is 390VDC Link voltage of PFC and the output has 16VDC/90W ratings. The efficiency measured is about up to 93%.