• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.1914-1927
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• 1996

Banyan networks have a number of applications in the area of computer and communications. While several analytical models have been proposed for the performance evaluation of Banyan networks, they are either not very accurate of too complex to be generalized. In this paper a new model for evaluating multibuffered MINs with 2*2 switching elements is proposed. the proposed model is very accurate for any size and traffic condition. It is also simple and can be easily generalized.

• Proceedings of the Korean Magnestics Society Conference
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• 2017.05a
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• pp.200-200
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• 2017

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.37-39
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• 2002

본 논문에서는 유한 요소법을 압전체에 적용하여 계산한 임피던스 파형을 실험적으로 검증하였으며 이를 선형 초음파 모터에 적용하여 선형 초음파 모터의 공진 특성을 해석하였다. 또한 선형 초음파 모터의 동작 특성 및 공진 모드의 타당성을 검증된 유한 요소법을 이용하여 검증하였으며 인가 전압 및 주파수에 따른 선형 초음파 모터의 속도 특성을 뉴럴 네트웍을 이용한 제어법을 통해 검증하였다. 선형 초음파 모터의 정밀 위치 제어의 가능성을 뉴럴 네트웍을 통한 제어법을 통해 검증하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.37-43
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• 2003

Parallel computing method is widely used in the computational fluid dynamics for efficient numerical analysis. Nowadays, low cost Linux cluster computers substitute for traditional supercomputers with parallel computing shcemes. The performance of nemerical solvers on an Linux cluster computer is highly dependent not on the performance of processors but on the performance of network devices in the cluster system. In this paper, we investigated the effects of the network devices such as Myrinet2000, gigabit ethernet, and fast ethernet on the performance of the cluster system by using some benchmark programs such as Netpipe, LINPACK, NAS NPB, and MPINS2D Navier-Stokes solvers. Finally, upon this investigation, we will suggest the method for building high performance low cost Linux cluster system in the computational fluid dynamics analysis.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.807-812
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• 2001

This paper represents the wall thinning analysis results for secondary side piping of two types of domestic nuclear power plants based on the DB establishment and F AC analysis study for NPP secondary system piping. CHECWORKS code utilized in this study has been applied world widely to wall thinning analyses for secondary side piping and its reliability has also been proved. The predicted wear rates for several piping systems of a pressurized water reactor NPP are compared with those of a pressurized heavy water reactor NPP and with the measured wear rates. On the basis of comparison results of the predicted and measured wear rates, the analysis results can be effectively applied to the development of a standard thinned pipe management program targeted all domestic nuclear power plants.

• 한국전산유체공학회:학술대회논문집
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• 2002.05a
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• pp.152-157
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• 2002

전산유체역학분야의 고속 연산을 위해서 병렬처리가 보편화되고 있으며 이러한 병렬해석은 주로 클러스터에서 저렴한 비용으로 수행되고 있다. 전산유체역학을 위한 클러스터 컴퓨터에서의 해석프로그램의 성능은 클러스터에 사용되는 프로세서의 성능뿐만 아니라 클러스터 내부의 통신 장비의 성능에 크게 좌우된다. 본 논문에서는 클러스터 컴퓨터의 구축에 널리 사용되고 있는 Myrinet2000, Gigabit Ethernet, Fast Ethernet 등의 네트웍 장치에 대해서 Netpipe, Linpack, NAS NPB, 그리고 MPINS2D Navier-Stokes 해석프로그램을 사용하여 성능을 비교하였다. 이를 통해서 향후 전산유체역학을 위한 클러스터 구축시 최대의 가격대 성능비를 얻을 수 있는 방법을 제시하고자 한다.

• Journal of Internet Computing and Services
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• v.4 no.5
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• pp.43-49
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• 2003

Analytical performance evaluation is crucial for justifying the merit of the design in different operational conditions. While several analytical models have been proposed for the performance evaluation of Multistage Interconnection Networks(MINs), they are mainly for uniform traffics. Even models for nonuniform traffics have several shortcomings such as they only consider output buffered structure or do not consider blocking conditions. In this paper the mere accurate models than any other ones so far have been proposed for the performance evaluation of banyan-type MIN's under nonuniform traffic condition is obtained. The accuracy of proposed model is conformed by comparing with the results from simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.220-222
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• 2004

이동 애드 혹 망을 구성하는 노드들은 일반적으로 배터리 전력을 사용하기 때문에 이들의 에너지 소모량을 줄이는 연구들이 각 계층에 대해 이루어져 왔다. 몇몇 연구들은 매체 접근 제어 프로토콜로 많이 이용되는 IEEE 802.11 DCF의 전력 소비량을 줄이기 위한 전력 제어 기법을 제시하였다. 기본 전력 제어기법(BASIC Power Control Protocol)은 RTS-CTS와 DATA-ACK 에 대해서 각각 다른 전력을 적용하는 것이다. RTS-CTS는 최대 전력으로 전송되고, DATA-ACK는 불필요한 에너지 낭비를 줄이기 위해 최소한 의 필요한 전력으로 전송하였다. 그러므로 DATA-ACK의 전송범위(transmission range)와 전송파 감지영역(carrier sensing range)은 RTS-CTS의 영역보다 작아진다. 전송파 감지영역에서 RTS-CTS를 감지한 노드들은 신호를 올바로 해석할 수 없으므로 NAV 값을 EIFS로 설정한다. 이 EIFS 구간은 충돌을 막기에는 너무나 짧기 때문에. EIFS 구간이 지난 후에 채널이 비어있는 상태로 간주하고 전송을 시도하게 된다. 이에 따라 DATA-ACK 수신에 있어서 충돌율이 증가하게 되고 네트웍 전체 처리량이 감소하게 된다. 본 논문에서는 기본 전력제어 기법이 가지는 문제점을 해결하고 전체 네트웍 처리량을 향상 시킬수 있는 새로운 전력제어(Power Control) MAC 프로토콜을 제안하였다.

• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.738-748
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• 2002

In this paper, a performance evaluation model of the Multistage Interconnection Network(MIN) with the multiple-buffered crossbar switches is Proposed and examined. Buffered switch technique is well known to solve the data collision problem of the MIN. The proposed evaluation model is developed by investigating the transfer patterns of data packets in a switch with output-buffers. The performance of the multiple-buffered${\alpha}{\times}{\alpha}$ crossbar switch is analyzed. Steady state probability concept is used to simplify the analyzing processes, Two important parameters of the network performance, throughput and delay, are then evaluated, To validate the proposed analysis model, the simulation is carried out on a Baseline network that uses the multiple buffered crossbar switches. Less than 2% differences between analysis and simulation results are observed. It is also shown that the network performance is significantly improved when the small number of buffer spaces is given. However, the throughput elevation is getting reduced and network delay becomes increasing as more buffer spaces are added in a switch.

• Journal of Internet Computing and Services
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• v.5 no.4
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• pp.35-42
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• 2004

In this paper the more accurate models than any other ones so far have been proposed for the performance evaluation of single-buffered banyan-type Multistage Interconnection Networks(MINs)'s under nonuniform traffic condition is obtained. Small clock cycle instead of big clock cycle is used. The accuracy of proposed models are conformed by comparing with the results from simulation.