• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.239-240
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• 2008

A new frequency offset estimator using low cross-property of PN sequences is proposed in the orthogonal frequency division multiple access (OFDMA) uplink systems. Simulation results show that the proposed estimator improves the mean square error (MSE) performance compared to conventional estimator [2] where each user have both different timing offset and different frequency offset. In addition, the MSE performance is improved as the length of PN sequence increases.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.144-144
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• 2005

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.8
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• pp.804-809
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• 2007

Initialization problem is defined for indoor mobile robot as a whole process from arrival to normal operation in a new environment. The unstructured environment make the process much more difficult compared to industrial robot in structured environments. We propose a simple and efficient initialization process based on artificial stars on ceiling. Important task points and paths connecting task points are defined based on the corresponding artificial stars. This approach can be used for all kinds of indoor mobile robots with landmarks used for indoor localization.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.364-366
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• 2007

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.267-273
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• 2007

• Journal of Magnetics
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• v.11 no.3
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• pp.119-122
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• 2006

We electroplated copper-cobalt thin films on a silicon substrate, which had 150 nm thick copper seed layer. The adhesion between the two metallic layers could be increased by utilizing a proper organic additive, pulse plating technique, and high temperature annealing. The thin films exhibited columnar growth of the deposits and enhanced adhesion. This is attributed to the grain growth mechanism introduced by the additive and annealing.

• Journal of Digital Convergence
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• v.6 no.1
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• pp.35-41
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• 2008

The digital economic environment of next generation, which digital high-technology industry appears to be the economic center of the high degree of industry structure, is expected to be developed as the existing traditional industry is merged with high tech digital one. The developing system of contents policy for digital industry means the policy and vision, and strategic structure which get the mechanism of contents industry structure to work. The promotion organization of digital contents policy is requested to secure the framework of digital contents industry based on cluster, the infra framework of digital infra culture, the infra framework of industry-academic cooperation, and the overall digital contents based on motive policy for the vitality of the youth. The application of digital contents policy may lead to establish the framework of the growth for the every unit of industry with the cluster oriented system.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.41-47
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• 2004

The objective of this research is to add convenience to the intranet operating within an educational institution by setting up a messenger function to enable it faculties and teachers to making better use of the university database via Intranet. With this massenger services, users can view the information about the members in a group they belong to, and register as friends a group of members they selected from the work group they are in. This function will reduce the cumbersome chores of adding one individual as a fiend at a time. This research will enhance the Intranet within an educational institution by integrating new functions.

• Journal of Digital Contents Society
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• v.4 no.2
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• pp.203-210
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• 2003

In this paper we proposed a new MAC protocol to improve QoS(Quality of Service) for real-time traffic in wireless Ad Hoc networks. NMAC protocol have a contention period reservation scheme and a priority control scheme to provide fairness of nodes and QoS. Through simulation, the NMAC protocol compared with existing CSMA MAC protocols shows improvement in performance.

• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.83-87
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• 1992

The ring expansion of 1,3-thiazolidines 4 derived from ${\beta}$-ketoacid derivatives to the corresponding dihydro-1,4-thiazines 1 by using the action of chlorine on 4 has been achieved. In the chlorinolysis unisolable sulfenyl chlorides 5 may be formed from chlorosulfonium ions 11 by ${\beta}$-elimination involving carbonyl activated methylene hydrogens. Addition of sulfenyl chloride to the internal double bond appears to form probable thiiranium ions 14, which in turn gave 1 with loss of acidic proton. Imminium ions 15 could be hydrolyzed easily to give enol 8. As a side reaction, dihydrothiazine that was formed was further chlorinated to produce dichlorides 16 which were rearranged readily to the chloromethyl compounds 10.