• Journal of the Institute of Convergence Signal Processing
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• v.9 no.2
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• pp.141-145
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• 2008

When the current flows to parallel lines with different length, it is researched that the radiation is occured by the common-mode current radiates, and the small light weight antenna composed of dual elements by using the principle is proposed. However, there is a problem in production about this antenna because this liner antenna is structured by combining with wires. In this paper, we improved this liner antenna, and designed the plane antenna composed of dual elements with different length in the plane printed board to produce and to design easily. Furthermore, the antenna with the wide-band characteristic is also designed in the same board. The radiation pattern is similar to the dipole antenna on account of designing the triangular patch S, the notch and two tapers in patch S, the notch and two tapers in the antenna element. In result, it was able to design the antenna working wider band-width(the bandwidth ratio about 58%, $VSWR{\le}2$).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.601-610
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• 2004

In this paper, the performance of an adaptive array antenna using Constant Modulus Algorithm (CMA) based on the signal structure for the IMT-2000 3GPP specification reverse link of an asynchronous direct sequence code division multiple access (DS-CDMA) system are evaluated. In addition, the performance is compared with the array antenna using Least Mean Square (LMS) based on the training signal. The simulation parameters such as the number of multipath, mu10pa1h intensity profiles between path, spreading gain and multiuser etc., are considered in the Monte Carlo simulation. Simulation results demonstrate an adaptive array antenna using CMA may give more capacity gain than the amy antenna using LMS in the case of multipath fading channel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.570-575
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• 2019

Active muffler is implemented by applying active noise control technique to reduce exhaust noise of automobile muffler. Conventional Filtered_x LMS algorithm has a problem that the degree of control filter becomes very large and convergence deteriorates when acoustic feedback is present. The recursive LMS algorithm can compensate for this problem because it can be easily diverted in the adaptive filter adaptation process. In this paper, the structure of the primary path and the secondary path transfer function is designed as the IIR filter to improve the convergence performance and the computational burden, and the stabilization filter algorithm is applied to secure stability which is a disadvantage of the IIR filter structure. The stabilization filter algorithm plays a role of pulling the pole into the unit circle to prevent the pole of the transfer function corresponding to the acoustic feedback from diverging during the adaptation process. In this way, the computational burden of the active muffler system and the convergence performance can be improved. In order to show the usefulness of the proposed system, we compared the performance of the proposed Filtered_x LMS algorithm with the performance of the proposed system for the exhaust sound of a diesel engine, which is a variable environment. Compared to conventional algorithm, proposed algorithm's computational burden is less than half, and convergence performances are more than 4 times.

• Convergence Security Journal
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• v.5 no.2
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• pp.37-42
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• 2005

Development of Information Technology and knowledge information society transfer brought huge change of education training field. According as Ubiquitous society approaches, e-Learning will be evolving by u-Learning. This presages in other form with present that professor-learner environment may change. This study proposes and embodied administration method of various studying contents by development of Learning environment, And through operation platform analysis, proposed LMS that can do practical use of contents efficiently.

• Journal of Digital Convergence
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• v.5 no.2
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• pp.25-36
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• 2007

In this paper, we studied on the effective structure of an e-Learning Korean Support System for foreigner based on computer systems which is to obey the rules of IMS/AICC International Standard regulations based on LCMS and SCORM. The most important task on this study is to support the function of self-study module through the review of the analysis and results of Korean learning and learning customs. We studied the effective PMS detail modules as well as the Standard Competency Module Management System, which related to LMS/LCMS, Learning an Individual Competency Management System, Competency Registry/Repository System, Knowledge Management System based on Community Competency Module, Education e-survey System and Module learning Support Service System. We suggested one of standard Effective Model of learning Korean Support System which is adopted in a various techniques for foreigner.

• Speech Sciences
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• v.4 no.2
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• pp.55-68
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• 1998

In this paper, a novel method of noise reduction of speech based on a complex adaptive noise canceler and method of optimal feature extraction are proposed. This complex adaptive noise canceler needs simply the noise detection, and LMS algorithm used to calculate the adaptive filter coefficient. The method of optimal feature extraction requires the variance of noise. The experimental results have shown that the proposed method effectively reduced noise in noisy speech. Optimal feature extraction has shown similar characteristics in noise-free speech.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.781-786
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• 2009

The cloud computing environment is a new trend of web based application parts. It can be IT business model that is able to easily support learning service and allocate resources through the internet to users. U-learning also is a maximal model with efficiency of the internet based learning. Thus, in this research, we proposed a design of u-learning's teaching and learning model that is applying the internet based learning. Proposal method is to fit u-learning and has 7 steps: Preparing, planning, gathering, learning process, analysis and evaluation, and feedback. We make a cloud u-learning server and cloud LMS to process and manage the service. And We also make a mobile devices meta data to aware the model.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.164-166
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• 2006

본 논문에서는 유비쿼터스 환경에서 사용자 중심의 모바일 에이전트를 설계하였다. 이는 쌍방향 통신을 기반으로 제공되는 학습 콘텐츠에 대하여 사용자의 편의 및 학습 효율을 극대화 하기위한 방안으로 모바일 기기와 센서의 기술을 결합한 디바이스로 설계하였다. 사용자 중심 모바일 에이전트는 기존 학습시스템 기반의 사용과 동시에 모바일 환경에서 보다 효과적인 교육시스템을 확장하기 위한 방안이다. 본 논문에서 제안하는 u-Learning 시스템에서 사용자중심 모바일 에이전트 설계의 결과 기존 LMS(Learning Management System)보다 적은규모로 보다 효과적인 사용자 정보 관리 및 학습 콘텐츠를 제공함으로써 차세대 교육환경에 획기적으로 기여 할 수 있을 것이다.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2007.11a
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• pp.123-123
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• 2007

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.446-454
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• 2009

In this paper, we propose u-learning hub site systems which are designed and implemented based on learning activities oriented components. The proposed systems are composed of component which can process the functionalities for coming into action of learning activities through various devices. Specially, each component is broken into class units by which learning activities of users can be performed on various devices. When users try to connect u-learning system in hub site, the system explores devices of users and connection program and then selects components that are fit to the activities and combines them in realtime. Through the methodology of u-learning hub site, the system proposed in this paper provides u-learning environment so that users can use the learning activity services taking no influence on time, place, devices and programs under the consistent system. That is different to traditional e-learning system which cannot support various devices of users directly.