• Annual Conference of KIPS
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• 2010.11a
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• pp.1050-1052
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• 2010

Locator and Identifier Split is considered as the solution to the scalability problem Internet is facing today. The separation approach of Locator and Identifier requires a third party called mapping system. The mapping system enables the inter-domain routing between two different edge networks. The design of this third party has generated many proposals, among them one approach use Border Gateway Protocol (BGP) for effective mapping information updates distribution. In this paper, we take advantage of this approach by considering the scalability in term of mapping information storage. Our goal is to provide scalability in term of mapping information storage as well as effective mapping information updates distribution.

• Journal of the Chungcheong Mathematical Society
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• v.28 no.1
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• pp.161-172
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• 2015

In this paper, we consider the chemotaxis-haptotaxis model of tumor invasion with the proliferation and tissue re-establishment term in dimensions one and two. We show the global in time existence of a unique classical solution for the the model in two dimensional spatial domain without any restrictions on the coefficients.

• Korean Journal of Mathematics
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• v.23 no.4
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• pp.619-630
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• 2015

This paper is devoted to investigate the multiple solutions for a class of the cooperative elliptic system involving subcritical Sobolev exponents on the bounded domain with smooth boundary. We first show the uniqueness and the negativity of the solution for the linear system of the problem via the direct calculation. We next use the variational method and the mountain pass theorem in the critical point theory.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.21 no.2
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• pp.81-87
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• 2017

In this note, we show that the cone property is satisfied for a class of dissipative equations of the form $u_t={\Delta}u+f(x,u,{\nabla}u)$ in a domain ${\Omega}{\subset}{\mathbb{R}}^2$ under the so called exactness condition for the nonlinear term. From this, we see that the global attractor is represented as a Lipshitz graph over a finite dimensional eigenspace.

• Bulletin of the Korean Mathematical Society
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• v.54 no.4
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• pp.1457-1470
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• 2017

In this paper, we consider the stabilization of the viscoelastic wave equation with variable coefficients in a bounded domain with smooth boundary, subject to linear dissipative internal feedback with a delay. Our stabilization result is mainly based on the use of the Riemannian geometry methods and Lyapunov functional techniques.

• Proceedings of the KSPS conference
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• 2003.10a
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• pp.97-100
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• 2003

This paper addresses a method of convolutive source separation that based on SEONS (Second Order Nonstationary Source Separation) [1] that was originally developed for blind separation of instantaneous mixtures using nonstationarity. In order to tackle this problem, we transform the convolutive BSS problem into multiple short-term instantaneous problems in the frequency domain and separated the instantaneous mixtures in every frequency bin. Moreover, we also employ a H infinity filtering technique in order to reduce the sensor noise effect. Numerical experiments are provided to demonstrate the effectiveness of the proposed approach and compare its performances with existing methods.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.11a
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• pp.297-302
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• 2002

특정 영역에 대해 사용자에게 관련 정보를 제공하는 서비스를 위해 정보 에이전트를 개발하고 있다. 이 시스템은 웹 상에서 문서를 수집해 오는데 특정 영역과 관련한 지식베이스를 토대로 하고 있는데, 이들 중 몇몇 전문 사이트 내의 정보가 많이 포함되어 있음을 볼 수 있다. 그러므로 전문 사이트 내의 관련 문서 수집은 중요한 의의가 있다. 본 논문에서는 이들 전문 사이트 내의 전문 문서 수집을 위해 문서간의 유사성을 토대로 클러스터링 한다. 즉, 문서내의 텀(term)과 HTML 태그(tag), 지식베이스의 WordNet 계층구조를 data로 하고 SVD(Singular Value Decomposition)을 사용하여 문서간의 관계를 밝혀내었다.

• East Asian mathematical journal
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• v.31 no.3
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• pp.351-356
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• 2015

In this paper, we study holomorphic discs in a domain with a plurisubharmonic peak function at a boundary point. The aim is to describe boundary behavior of holomorphic discs in convex finite type domains in the complex Euclidean space in term of a special local neigh-borhood system at a boundary point.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.12
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• pp.1806-1814
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• 1993

Efficient speech coders using tree coding combined with harmonic scaling are designed at the rate of 4.8 kilobitts/sec (kbps). A time domain harmonic scaling algorithm (TDHS) is used to compress input speech by a factor of two. This process allows the tree coder have 1.5 bits/sample for 4.8 kbps in the case of a 6.4 kHz sampling rate. In the backward adaptive tree coder, there are three components of the code generator, including a hybrid adaptive quantizer, a short-term predictor and a pitch predictor. The robustness of the tree coder is achieved by carefully choosing the input of the short term predictor adaptation. Also, inclusion of a smoother in the pitch predictor improves the error performance of tree coder in the noisy channel. Subjectively, tree coding combined with TDHS provides good quality speech at 4.8 kbps.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.6
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• pp.496-501
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• 2005

This paper presents experimental results of the frequency offset locking of He-Ne lasers and the stability analysis. The master laser is free running, and the slave laser is a single-mode operating laser. The frequency difference of two lasers is stabilized to 200 MHz which can be synchronized using PLL servo. The measured beat frequency between two lasers was 200.004 MHz ${\pm}$ 0.15 MHz. The square root of Allan variance as a measure of stability in time domain is also measured. The long-term stability of the beat was worse than sort-term stability. With a gate time $\tau=1000\;s$, the square root of Allan variance was about 1 GHz. The results of the square root of Allan variance of the stabilized beat signal was a gate time of $\tau=1000\;s$, the square root of Allan variance was about 1.5 kHz. The long-term stability was improved by more than several hundred times compared with that without the stabilization.