• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.4
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• pp.76-82
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• 2010

For the purpose of controlling the beam tilt angle of the base station sector array antenna, phase shifter is used. Phase angles of this antenna depending on the tilt angles are designed, and the patterns on the vertical and horizontal planes are simulated and analyzed for the evaluation of base station antenna. This analysis is used in the optimal design of base station antenna because of maximum cell coverage and incremented traffic capacity, decreased interference.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.1
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• pp.65-72
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• 2009

For the evaluation of far-field performance by using the near-field probing on the base station dipole array antenna, the effects of mutual coupling depending on the heights between the array antenna with reflector and the probe were analyzed. When the height is varied in the near-field region, S parameters on the input ports of antenna and probe are measured and analyzed to decide the height for the minimum mutual coupling effect and the maximum probing efficiency. This height will be applicable to the near-field probing system design to achieve the precision far-field performance of a base station array antenna system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.3
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• pp.301-303
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• 2016

This paper proposes a method providing diversity gain using small base stations in a cell coverage in order to improve diversity gain. The small base stations and the conventional base station consist a virtual MIMO array by using the cooperative communication scheme. Also, transmission diversity scheme is applied. A mobile user can receive the signals having the improved reliability by the applied transmission diversity scheme and the cooperative communication scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.917-920
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• 2006

In mobile environments, their is more than one propagation path between each transceiver and Receiver have two or more delayed multipath signals. Delayed multipath signals can cause ISI and Receiver needs a adaptive algorithm to estimate a channel periodically. Also adaptive antenna using adaptive algorithm provide a significant increase in capacity, performance and coverage. This paper describes various LMS algorithm and evaluate the performance of array antenna Base station by using LMS algorithm in the presence of multipath signals and multiple users. As a result of simulation, Adaptive array antenna systems are able to adjust their antenna pattern to select desired signals, and reduce interference.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.129-132
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• 2004

본 논문에서는 비전 기반 구륜이동로봇이 복도를 주행하기 위해 필요한 벽면으로부터의 거리와 방향각을 신경망을 이용하여 추정하는 알고리즘에 대해 기술하였다. 복도에 설치된 조명을 표식으로 사용하였고, 구륜이동로봇의 위치와 각도에 따라 조명들의 배열선과 정의된 소멸점의 위치는 다르게 된다. 따라서 조명의 배열선과 소멸점의 위치에 관한 두개의 평면을 구성하였다. 조명의 배열선과 소멸점의 위치는 간단한 영상처리 알고리즘을 통하여 획득하였다. 기지의 위치와 각도에서의 조명의 배열선과 소멸점의 위치에 대한 데이터를 획득하였다. 획득된 데이터를 이용하여 신경망을 구성하고 학습시켰다. 학습을 통해 수정된 신경망을 이용하여 실제 주행에 적용하였다.

• 한국ITS학회:학술대회논문집
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• v.2007 no.10
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• pp.136-140
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• 2007

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1677-1688
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• 1998

In this paper, we analyze the performance of a DS-CDMA system employing adaptive adaptive array antenna technology at base-station. For the analysis the receiving architecture of a multiple team adaptive base-station array antenna is proposed as a major system omponent, and signal to interference and noise ratio(SINR) on the proposed architecture is developed. We show that the perfomance enhancement of the CDMA system is represented as great reduction of interfreence by employing an array antenna capable of resolving the angular distribution of the mobile users as seen at the ase-station. The energy associated with each mobile or a group of mobiles is thus confined within the addressed volume, greatly reducing the amount of co-channel interference experienced from and by neighboring co-channel cells. In order to ascertain the benefits of such an antenna, a theoretical approach, which eis based on the conventional and proposed antenna systems in a typical mobile radio environment, is adopted. Finally computer simulation results show the insight into how the adaptive array antenna operates when used in conjunction with DS-CDMA and illustrate the potential benefits in the SINR point of view.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2
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• pp.426-436
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• 2000

Given a linear arrangement of n base stations which generate multiple types of traffic among themselves, we consider the problem of finding a set of disjoint clusters to cover n base statons so that a cluster is assigned a location server. Our goal is to minimize the total communication cost for the entire network where the cost of intra-cluster communication is usually lower than that of intercluster communication for each type of traffic. The optimization problem is transformed into an equivavalent problem using the concept of relative cost, which generates the difference of communication costs between intracluster and intercluster communications. Using the relative cost matrix, an efficient algorithm of O($mm^2$), where m is the number of clusters in a partition, is designed by dynamic programming. The algorithm also finds all thevalid partitions in the same polynomial time, given the size constraint on a cluster, and the total allowable communication cost for the entire network.

• Composites Research
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• v.26 no.4
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• pp.235-244
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• 2013

A volume integral equation method (VIEM) is introduced for the solution of elastostatic problems in an unbounded isotropic elastic solid containing multiple isotropic elliptical fibers of arbitrary orientation subject to uniform stress at infinity. The fibers are assumed to be long parallel elliptical cylinders composed of isotropic elastic material perfectly bonded to the isotropic matrix. The solid is assumed to be under plane strain on the plane normal to the cylinders. A detailed analysis of the stress field at the matrix-fiber interface for square and hexagonal packing of the fibers is carried out for different values of the number, orientation angles and concentration of the elliptical fibers. The accuracy and efficiency of the method are examined through comparison with results obtained from analytical and finite element methods.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.92-92
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• 2003