• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.3
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• pp.494-507
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• 2011

In this paper, we propose two schemes to reduce the complexity of fixed-complexity sphere decoder (FSD) algorithm in the ordering and tree-search stages, respectively, while achieving quasi-ML performance. In the ordering stage, we propose a QR-decomposition-based FSD signal ordering based on the zero-forcing criterion (FSD-ZF-SQRD) that requires only a few number of additional complex flops compared to the unsorted QRD. Also, the proposed ordering algorithm is extended using the minimum mean square error (MMSE) criterion to achieve better performance. In the tree-search stage, we introduce a threshold-based complexity reduction approach for the FSD depending on the reliability of the signal with the largest noise amplification. Numerical results show that in 8 ${\times}$ 8 MIMO system, the proposed FSD-ZF-SQRD and FSD-MMSE-SQRD only require 19.5% and 26.3% of the computational efforts required by Hassibi's scheme, respectively. Moreover, a third threshold vector is outlined which can be used for high order modulation schemes. In 4 ${\times}$ 4 MIMO system using 16-QAM and 64-QAM, simulation results show that when the proposed threshold-based approach is employed, FSD requires only 62.86% and 53.67% of its full complexity, respectively.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.213-223
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• 2007

E-Business Platform for SMEs in GMS Countries(GMSEB) is a E-business service portal which based on Yunnan, face to ASEAN, connect with China's mainland. lt is established by Kunming Dongxun Sic&Tech Co.,Ltd and E-Business Centre of Yunnan University of Financial & Economics, who get supports from UNESCAP, Science and Technology Department of Yunnan Provincial and Yunnan SMEs Bureau. The portal will bulid a B2B & B2C E-business and. ASP portal to provide service of e-business and enterprise management informatization according with the different languages and situation to China and GMS countries. The paper starts with analysis of the policy in China of promoting GMS cooperation and exchanges, importance of Yunnan and cultural universality in GMS countries. It expounds the necessity of establishing such a regional e-commerce platform. The project explores how to develop the model of e-business and enterprise management informationization for SMEs under the condition of weak economic strength and scarcity of Information Technology talents. To promote the SMEs in GMS countries participate in the integration with the global economy through the international SMEs'E-business Platform, make a fairly rapid progress by full play to its advantages.

• Journal of Information Management
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• v.27 no.2
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• pp.1-32
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• 1996

By the 1990s, Database Online Searching and CD-ROM Searching have been used universally in libraries. Due to their ease of use and facilitation, it is believed that such new media searching will produce more benefits than the usual printed materials. Furthermore, from the library management's point view, the new media searching's ability to minimize holding space will be another example of the advantage. The new media searching will have ever the printed materials. However, since it Is necessary to have an objective appraisal of the cost effectiveness in the implementation and the design of the new media system, it will be compared the new media searching with the conventional searching by using printed materials at the KIEP Library and Data Bank.

• Journal of Community Nutrition
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• v.5 no.4
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• pp.209-217
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• 2003

The food and nutrition system is a network of processes linking agriculture, food, eating, nutrition, and health. The system includes a series of nine stages (production, processing, distribution, acquisition, preparation, consumption, digestion, transport, and utilization) and two types of contexts (biophysical and sociocultural). Analysis of whole food and nutrition systems provides information about the structure and processes involved in the complete scope of food and nutrition, assisting in the identification of ″upstream″ influences and ″downstream″ consequences in the system. The current analysis gathered existing data about the food and nutrition system in South Korea from public sources and professional publications, and interpreted that information to consider how different elements of the system contribute to health. The findings revealed that South Korea has substantial domestic food production and processing supplemented by imports, widespread food distribution in markets and a growing number of Korean and Western restaurants, a relatively low percentage of household income spent on food, growing use of new food preparation methods such as microwave ovens, a rice/vegetable/fish based three-meal consumption pattern, few recorded digestive problems, increasing calorie storage as body fat, and a relatively low chronic disease prevalence compared to other developed societies. Examination of the full scope of the food and nutrition system provides a broad perspective using whole system thinking that can identify potential strategies for future research and intervention.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3751-3774
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• 2014

With the rapid development of wireless communication, the confliction between the scarce frequency resources and the low spectral efficiency caused by the stationary spectrum sharing strategies seriously restricts the evolution of the future mobile communication. For this purpose, cognitive radio (CR) emerges as one of the most promising inventions which can overcome the spectrum shortage. As the key technology and main objective of CR, spectrum sharing can make full use of the limited spectrum, alleviate the scarcity of frequency resources and improve the system utilities, playing thereby an important role in improving the system performance of cognitive radio networks (CRNs). In this survey, the spectrum sharing in CRNs is discussed in terms of the sharing process, mainstream sharing technologies and spectrum sharing models. In particular, comparisons of different spectrum sharing strategies are concluded, as well as that of different spectrum sensing schemes in sharing procedure. Moreover, some application examples of the spectrum sharing in CRNs, such as smart grid, public safety, cellular network and medical body area networks are also introduced. In addition, our previous related works are presented and the open research issues in the field of spectrum sharing are stated as well.

• The Journal of the Korea Contents Association
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• v.12 no.7
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• pp.1-10
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• 2012

Today, As the internet and electronic publishing technology was powerful and there are many benefits to using various academic information which has an electronic document of high quality. Many researchers had much required to see a full-text of electronic document. There was an requirement of digital achieving activities between countries for each other electronic document in order to safely preserve and services. In this paper, we have implemented an electronic document local-hosting system to provide free service to KESLI member institutions and provide pay-per-view service to individual users and small/medium size companies who are not member of KESLI and builded national long-term preservation system of electronic information resources.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.2
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• pp.155-163
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• 1989

For a one link flexible arm control, quadratic optimal control is applied to the dynamic modilling which is derived from an assumed mode method. For the quadratic optimal control technique, the full state feedback must be obtained for closing the control loop, but because some of the states in the flexible system(e.g. the rate of change of the time dependent variables of the mode shapes) can not be directly measured, state estimator is necessary to achieve the practical implementation of the optimal controller. When disturbances and measurement noise occur, stochastic approach must be applied to estimating the states of the system. Kalman Filter is used as a stste estimator. Through the simulation, the flexible system with state estimator is compared with the flexible system assuming that all the states can be measured.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.56-63
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• 2000

In this paper, we design new high performance ATM switch architectures based on a Generalized Shuffle network(GSN). The GSN is a distributed network topology with the number of nodes in O(N). To improve the throughput of the switch, a layering strategy called Weaved GSN(WGSN). WGSN has an additional connection links between switching elements which locate in the same position of adjacent GSNs. The analysis and simulation are performed under uniform and full load conditions, and the results show that the proposed switch has better throughput and cell loss performance when compared with other banyan-based switch architectures known so far.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1398-1415
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• 1996

Instead of using three charge-coupled devices (CCDs) for the corresponding color channels, most consumer's most consummer's color macmorders reconstruct color images by using only one CCD with a color filter array (CFA), which periodically samples different color signals. By this reson the resulting image cannot produce the full resolution of the input image. More sepecifically, a single-CCD color camcorder reconstructs red, greed, and blue color channels from a color filter array followed by a CCD. During the reconstruction process, color cross-talk among channels (interchannel distortion) and eriodically space-verying blur (intrachannel distortion) occur. The proposed restoration system reduces distortions due to interchannel interference, and then restores each color channel by removing the corresponding intrachannel distortion. Experimental results show that the proposedsystem provides the improved image in oth objective and subjective senses. A major advantage of the proposed system is feasible to real-time image improvement because it can be implemented by a finite impulse response (FIR) filter structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1718-1731
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• 1998

Digital quadrature demodulator is needed for the coherent demodulation in the digital communication systems such as Binary Phase-Shift-Keying, Quadrature Phase-Shift-Keying, and Quadrature Anmplitude Modulation. Conventaionally, the DDFS (Direct Digital Frequency Synthsizer) is used for generating the carrier signal and seperate multi-pliers are used for mixing. And the DDFS is implemented using the ROM (Read Only Memory), which can be a bottle-neck neck when the fast-speed and small-area implementation is required. A new architecture is developed, which employs the circular rotation mode of the CORDIC algorithm for signal mixing as well as carrier generation. To optimize the hardware design parameters, the finiteword-length effects of the proposed implementation arachitecture are analyzed in comparison with a conventional ROM-based architecture. The hardware costs are also estimated, which showed that the proposed architecture occupies only a third of the area of the conventional ROM-based architecture for the same performance. A full-custom VLSI is developed using the proposed architecture.