• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1523-1531
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• 2011

Multi-axle driving vehicle are favored for military use in off road operations because of their high mobility on extreme terrains and obstacles. Especially, Military Vehicle needs an ability to driving on hills of 60% angle slope. This paper presents the improvement of the ability of hill climbing for 6WD/6WS vehicle through the optimal tire force distribution method. From the driver's commands, the desired longitudinal force, the desired lateral force, and the desired yaw moment were obtained for the hill climbing of vehicle using optimal tire force distribution method. These three values were distributed to each wheel as the torque based on optimal tire force distribution method using friction circle and cost function. To verify the performance of the proposed algorithm, the simulation is executed using TruckSim software. Two vehicles, the one the proposed algorithm is implemented and the another the tire's forces are equivalently distributed, are compared. At the hill slop, the ability to driving on hills is improved by using the optimum tire force distribution method.

• Journal of Korea Multimedia Society
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• v.7 no.8
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• pp.1097-1106
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• 2004

The typical web cluster architecture consists of replicated real servers and a virtual server that routes client requests among the real servers. In this paper, we proposed an efficient dynamic load distribution method with load prediction for the web cluster systems. The virtual server transmit status request message to real servers in other to get load states. However the load states dose not accurate during load distribution, thus the virtual server predict the load status of real servers and assign a request of the client to the minimum loaded real server. The proposed distribution methods works not related to partial breakdown of real servers, thus the system works with high availability. We also show that the proposed distribution method preserve scalable property and improve the throughput through a set of simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1134-1138
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• 2008

In this paper, the synthesis of distributed impedance transformers is presented that is essential for power divider design, whereby a broadband power divider is designed. Transfer functions of distributed transformers are synthesized with Chebyshev approximation, and their element values are calculated for various minimum insertion losses(MIL) and ripples. Desired performance of transformers is obtained by optimizing MIL's and ripples of a transfer function. As an application example, a four-way power divider is designed that operates over 2 to 8GHz frequency range. Experimental results are shown to approach the design performance, so transformer design by distributed network synthesis proves to be useful to power divider design.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.8
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• pp.805-814
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• 2011

Aluminum plate-fin heat exchangers (ALPHEs) are widely used in petroleum and gas-treated processes. The performance of the ALPHE is strongly dependent on the distribution characteristics of the header and the distributors of each fluid. In this paper, we define the aspect ratio in the side-entry type distributor and analyze the distribution characteristics using CFD-based numerical methods. The phenomena of velocity deviation and distribution with the aspect ratio and the inlet Reynolds number were analyzed by applying relative and absolute maldistribution parameters, and an optimum aspect ratio with the inlet Reynolds number was presented.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.534-537
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• 2009

최근 자동차 배기가스 규제가 더욱 강화됨에 따라 완전 연소를 통한 배기가스 저감에 관하여 많은 연구가 진행되고 있다. 특히, 고온 연소시 문제가 되는 질소 산화물의 저감을 위해 많은 노력을 기울이고 있다. 질소 산화물을 저감하는데 효과적인 EGR 기술의 도입이 보편화되고 있지만, 각 실린더별 EGR 분배 특성에 따라 엔진의 성능이 달라지는 역효과가 발생한다. 시제품을 동한 EGR 분배특성 파악은 비용과 시간 측면에서 상당한 난제가 산재해있다. 본 연구에서는 이러한 실험시간과 비용 절감을 위하여 1D 성능해석 프로그램인 GT-Power를 적용 EGR의 분배특성을 예측하였다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.556-563
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• 2003

반도체 산업은 글로벌하게 공급사슬이 형성되어 있고, 공급사슬 구성에서 다른 제조산업과 구별되는 독특한 특징을 가지고 있다. 본 논문은 reentrancy공정과 binning특성을 고려한 반도체 산업의 생산과 분배망에 대한 공급사슬 모형을 제안한다. 3가지 생산 정책과 2가지 분배 정책에 대한 수리모형을 수립하여 총 5가지 공급사슬 모형을 형성하였고, 각각의 모형에 대해 해를 도출하여 비교, 분석하였다. 생산공정에서는 Balance정책, 분배공정에서는 Pull정책을 조합한 모형이 다른 모형들보다 더 좋은 성능을 보여 주고 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.241-242
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• 2011

SRC 프로토콜은 BCDCP 클러스터 라우팅 기법과 페어와이즈 키와 디지털서명을 이용한 키 분배 프로토콜을 결합한 클러스터링 기반 보안 프로토콜이며, 초기 키 생성 및 분배, 주기적인 키 재 생성, 센서 추가 및 센서 단계로 구성되어 있다. 본 논문에서는 SRC 프로토콜의 한계점인 페어와이즈 키의 선분배를 이용한 보안방법의 개선과 에너지 사용량을 개선하기 위한 초기 키 생성 및 분배단계를 분리하여 초기 키 생성 단계와 분배단계를 제시한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.39-58
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• 2004

It is very important that predict the inelastic seismic behavior exactly for seismic performance evaluation of a building in the performance based seismic design. Evaluation method of seismic performance based on the pushover analysis reflected in PBSE was developed by some researchers. For the evaluation of inelastic global and local seismic responses by pushover analysis exactly. lateral load distribution should be adjusted and reflected the dynamic characteristics of structural system and various seismic ground motions. And performance point should be determined based on the evaluation of reasonable deformation capacity of a building more exactly. An effective method based on the improved the adaptive lateral load distribution and the equivalent responses of a multistory building is proposed in this study to efficiently estimate the accurate inelastic seismic responses. The proposed method can be used to evaluate the seismic performance for the global inelastic behavior of a building and to accurately estimate its local inelastic seismic responses. In order to demonstrate the accuracy and validity of this method, inelastic seismic responses estimated by the proposed method are compared with those obtained from other analytical methods.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.452-454
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• 2000

최근 인터넷의 사용이 크게 증가하면서 웹을 이용한 상품 및 서비스가 크게 보급, 확산되고 있으나 상대적으로 빈약한 성능과 신뢰도를 제공한다. 클러스터링 기법은 비용 측면에서 매우 유리하며 특히 웹서비스나 정보 시스템과 같이 고성능과 고가용도를 요구하는 응용 분야에서 결함 허용 컴퓨터의 대안으로 등장하고 있다. 본 논문에서는 고가용도 및 확장성을 제공하는 클러스터링 웹 서버를 대상으로 부하 분배기의 구조를 제안하고 문서 접근 확률과 문서 크기 정보를 이용한 부하 분배 알고리즘을 개발하여 성능을 최대화할 수 있도록 하였다. 특히 제안된 알고리즘은 각 서버 노드가 동일한 운영체제로 구성되지 않아도 되고 처리 용량이 서로 달라도 되며 기존의 알고리즘에 비해 캐쉬 적중률을 향상시킨다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.87-92
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• 2015

In this Paper, we proposed optimization of system performance, optimal splitting factor ${\alpha}$ applied to power splitting protocol with relay protocol with decode and forward undergo co-channel interference. We can possible to optimize and maximize the channel capacity of the receive performance and the efficiency of the network through optimal factor of splitting protocol. We verified BER performance and Channel capacity and Outage probability for the proposed scheme over Rayleigh fading through Monte-Carlo simulation.