• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.4
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• pp.69-78
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• 2010

The irreversible 9/7 JPEG2000, which is one of sub-band coding techniques, has a problem of severe picture quality distortion at the edge and the background caused by the quantization error below 0.15bpp. In this paper, to solve such problems we propose a VQ(Visual Quantizer) based on L-pdf(Laplace probability density function) statistical characteristics of high frequency sub-bands. The proposed VQ is designed by visual parameter for improving the subjective quality and weighting parameter for increasing the compression ratio. A proposed method, based on 9/7 JPEG2000 scheme, gives the high subjective quality to reconstructed images below 0.15bpp and provides minimum MSE(Mean-Squared Error) regardless of the compression ratio.

• Animal Systematics, Evolution and Diversity
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• v.20 no.2
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• pp.87-98
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• 2004

Two pagurid hermit crabs of the genus Pagurus, P. proximus Komai, 2000 and P. simulans Komai, 2000, were collected from the East Sea of Korea are reported. Brief descriptions and illustrations of these two species are provided. Both have been confounded with P. brachiomastus (Thallwitz, 1891) until recently Komai (2000a) reviewed the taxonomic status of this species complex. Kim's (1973) record of P. brachiomastus from Korea was synonymized to P. proximus by Komai (2000a) and the latter in Korean waters is confirmed through this study. P. simulans is recorded for the first time from Korea as well as the East Sea (Sea of Japan).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.89-95
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• 2003

This paper proposes downlink blocking model and approximation equation using lower bound approximation in order to determine the proper guard band between cdma2000 1X and WCDMA in handover areas. The frequency sharing conditions obtained by the model and approximation equation on blocking probability proposed in the paper, are co-site of base station and guard band higher than 1 MHz. Also, the proposed equation is in the form of Q-function. It is an analytical solution overcoming the drawback of recalculation, belonged to Monte-Carlo technique.

• Korean Management Science Review
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• v.25 no.1
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• pp.29-41
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• 2008

In the mobile communication service market, this study represents an attempt to forecast the subscribers of the IMT-2000 service market using the questionnaire of experts which is the qualitative technique is used. In this study, by using the substitution model of next generations among products in order to analyze the IMT-2000 demand of service, a demand was predicted. And by estimating the market demand prospect in which it becomes the important factor of the IMT-2000 service diffusion according to each bandwidth frequency the politically necessary approaching direction about the frequency was presented. It will be able to become the important part to not only the business carrier but also the policy maker to examine a prospect toward the subscriber of the IMT-2000 service. As a result, the market demand was exposed to be most big when the SKT 800MHz, and the KTF 800(900)MHz were used as the additional frequency. And it was likely to reach to the IMT-2000 number of subscribers to about 35.750 thousand peoples in the future at 2015.

• The Journal of the Korea Contents Association
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• v.3 no.3
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• pp.74-84
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• 2003

The Location Service (LCS) feature which provides the terminal UE’s geographical location information has been important issues in IMT-2000 system. The existing location positioning methods are classified into the cell ID based, OTDOA, and network assisted GPS. In this paper, a new hybrid location positioning method which combine three of these methods is proposed. Then the LCS protocol is developed under SDL (Specification and Description Language) development environment after designing a new LCS system architecture and behavior. This protocol design covers the LCS functional model and signaling procedure, system architecture, primitive and data structure, and process SDL diagrams.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.146-150
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• 2009

Nowdays needs the new still image compression standard. JPEG2000 has been developed. JPEG2000 divide DWT and EBCOT. EBCOT is consisted of Bit Plane Coding and ARithmetic Coding algorithm. In this paper, we proposed BPC algorithm that is efficient context-based generation. Proposed BPC Algorithm forecasted coding pass using SigStage, column, mpass value. BPC designed using Verilog HDL. H/W implemenates using Xillinx FPGA technology.

• ETRI Journal
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• v.27 no.6
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• pp.697-707
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• 2005

This paper proposes a new design of directional couplers with high directivity for personal communication services (PCS) and International Mobile Telecommunications-2000 (IMT-2000). The directional coupler is used to check and verify the power, frequency, and antenna reflection of a signal at transmission stations for mobile communications. The performance requirements of directional couplers are a strong coupling to reduce the effect on the transmitted power and high directivity to suppress the interference of the reflected signals and reduce the errors in communication. So far, various architectures have been proposed to gain high directivity, and there have been many studies used to obtain a strong coupling. However, conventional architectures for high directivity and strong coupling have a directivity of only about 20 dB, and there have been difficulties to achieve the higher directivity of 30 dB suitable for PCS and IMT-2000. This paper proposes a new architecture of directional couplers based on a grounding composed of strip lines, and compares the test results of this directional coupler with conventional ones. The results show that the proposed directional coupler has a directivity of more than 30 dB and is adequate for PCS and IMT-2000.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.11-17
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• 2001

This paper introduces an interference analyzer based on the statistical approach called the Monte Carlo methodology, which has been chosen as one of the interference analyzing techniques in ITU-R. Furthermore, using the interference analyzer developed in this paper with modified Hata model, computer simulation is performed to examine probability of interference affecting between the base stations with FDD and TDD modes for IMT-2000. Through the simulation results, it is confirmed that two different systems with FDD/TDD modes of same frequency bands can be simultaneously used in a cell without significant interference, under the parameter conditions specified in this paper.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1277-1285
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• 2003

In this paper, we present a conference key authentication mechanism by employing an algebraic method on IMT-2000 environment. To accomplish this, the symmetric balanced incomplete block design is applied for generating a conference key and then this key is distributed to participants. Through the technique for creation of a conference key and mutual authentications peformed based on identification information, a communication protocol is designed. The protocol proposed minimizes the communication complexity for generating a conference key. On a special case the complexity is O(equation omitted), where v is the number of participants. The security of the mechanism, which is a significant problem in construction of secure systems, can be assured since finding discrete logarithms is generally a hard problem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1620-1627
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• 2001

In this paper, a broadband microstrip antenna for PCS and IMT-2000 service is designed. To obtain the broadband characteristics of an antenna, we utilized the multi-layered structure composed of two foam material layers, parasitic element and aperture coupled feeding network. The broadband characteristic is obtained by changing the size of parasitic element and the height of foam materials. In addition to that, the usage of metal layer at the distance of λ/4 from feed-line, back radiation is reduced. The bandwidth of a single element for VSWR less than 1.3 is about 550MHz. The bandwidth of a designed 1$\times$4 array antenna for VSWR less than 1.3 is about 460MHz. The gain of a designed array antenna is about 11.15∼12.15dBi and the front-to-back ratio is about 30dB.