• 대한전기학회논문지:전력기술부문A
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• 제49권6호
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• pp.272-279
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• 2000

This paper describes a controller design and dynamic performance analysis of UPFC based on 3-level inverters. Major attention is focused on the controller design for both shunt and series inverters, including regulator design for the dc link voltage sharing across the dc capacitors. An energy-based approach was investigated for effectively designing the controller. A detailed UPFC model has been developed with EMTP using 24-pulse 3-level inverters to verify this approach. Simulation results about dynamic performance of UPFC confirm effects for increasing transmission capacity and damping low-frequency oscillation. The developed simulation model would be very effective to analyze the dynamic performance of UPFC.

• 한국군사과학기술학회지
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• 제16권5호
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• pp.666-674
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• 2013

This paper studied about the design and implementation of tactical communication network simulator in order to obtain tactical communication network parameter, such as link capacity and routing plan, and a number of exceptional cases that may occur during actual deployment by conducting simulation of a large-scale tactical communication networks. This tactical communication network simulator provides equipment models and link models of commercial OPNET simulator for tactical communication network. In addition, 6 types of simulation scenario writings convenience functions and traffic generation models that may occur in situations of tactical communication network environment were implemented in order to enhance user friendliness. By taking advantages of SITL(System-In-The-Loop) function of OPNET, the tactical communication network simulator allows users to perform interoperability test between M&S models and actual equipment in operating simulation of tactical communication network, which is run on software. In order to confirm the functions and performance of the simulator, small-scale of tactical communication network was configured to make sure interoperability between SITL-based equipment and a large-scale tactical communication network was simulated and checked how to cope with traffic generated for each network node. As the results, we were able to confirm that the simulator is operated properly.

• 한국시뮬레이션학회논문지
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• 제22권1호
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• pp.41-51
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• 2013

이 논문에서는 EV-DO나 브로드캐스트 멀티캐스트 서비스와 같은 CDMA 셀룰러 표준을 목표로 하는 시스템 수준 시뮬레이터의 설계 방법론을 소개한다. 셀 레이아웃, 모바일 분포, 채널 모델링, 수신 전력 계산, 스케줄링, 패킷 에러 예측, 트래픽 생성 등의 절차를 따라 가면서, 시스템 수준 시뮬레이터의 기본 구조와 시뮬레이션 흐름을 기술하였다. 시뮬레이터를 모델링하기 위해, CDMA 시스템과 EV-DO 방송 시스템의 순방향 링크에서의 패킷 데이터 전송을 고려하였다. 셀룰러 표준을 위한 시스템 수준 시뮬레이터는 상위 수준 언어로 모델링 및 개발 되었고, 용량과 커버리지를 포함한 에어 접속부 성능 지표들을 계산 및 예측하는 데에 이용되었다.

• Journal of Electrical Engineering and Technology
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• 제6권4호
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• pp.505-512
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• 2011

A novel passive boost power converter forsingle-phaseswitched reluctance motor is presented. A simple passive circuit is proposed comprisingthree diodes and one capacitor. The passive circuitis added in the front-end of a conventional asymmetric converter to obtain high negative bias. Based on this passive network, the terminal voltage of the converter side is a general DC-link voltage level in parallel mode up to a double DC-link voltage level in series mode. Thus,it can suppress the negative torque generation from the tail current and improve the output power. The results of the comparative simulation and experiments forthe conventional and proposed converter verify the performance of the proposed converter.

• 대한토목학회논문집
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• 제26권2D호
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• pp.233-239
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• 2006

지금까지의 링크통행시간에 대한 연구는 개별 차량의 평균을 통한 평균링크통행시간 산정 및 추정의 제한적인 연구가 대부분이었다. 그러나, 링크통행시간은 교통조건, 신호운영조건, 도로조건 등 다양한 영향인자로 인해 통행시간 분포가 구분되는 특성을 나타낸다. 링크통행시간 분포특성에 대한 선행연구결과 통행시간이 양분되어 분포하는 것으로 나타났으며 따라서, 링크통행시간의 경우 평균통행시간에 의한 결과보다 신호지체가 발생하지 않는 통행시간과 신호지체가 발생하는 통행시간으로 구분하는 것이 교통상황을 인식하는데 바람직할 것이다. 본 연구에서는 통행시간 분포특성 및 원인을 분석하였으며, 프로그램을 이용한 시뮬레이션을 통해 보다 다양한 조건을 부여하여 링크통행시간분포비율에 영향을 주는 변수들에 대한 검토하고 통행시간 분포비율을 추정할 수 있는 모형을 구축하였다. 먼저 링크통행시간 분포비율을 추정하는 회귀모형과 퍼지근사추론 모형을 구축하였다. 추정 모형을 구축하기 위한 변수를 분석한 결과 잔류녹색시간과 대기행렬 대수가 높은 상관성을 가지는 것으로 분석되었으며, 따라서 이를 이용하여 추정모형을 구축하였다. 구축결과를 비교 검토한 결과 퍼지근사추론 모형이 회귀모형에 비해 추정의 신뢰성 및 적용성에서 더욱 우수한 것으로 나타났다.

• Journal of Power Electronics
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• 제15권6호
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• pp.1421-1428
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• 2015

The efficiency and reliability of the dual-buck inverter (DBI) were greatly improved by eliminating the shoot-through problem and optimally designing the freewheeling diode. The traditional DBI suffers from large harmonic components with low output voltage and large capacity output filter inductor. To overcome the aforementioned disadvantages, a modified DBI (MBDI) was proposed by adopting a quasi-resonant link and pulse density modulation (PDM). This paper first introduces the working principle of the MBDI and PDM, and then the selection principle of system parameters is presented. Finally, a mathematical model of the MBDIis built, and an experiment prototype is set up. Simulation and experimental results verify the correctness of the theoretical analysis and the feasibility of the scheme.

• 한국통신학회논문지
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• 제42권2호
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• pp.383-385
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• 2017

For the purpose of providing high data rate real-time services, radio transmission technologies for ship ad-hoc network based on the Recommendation ITU-R 1842-1 are designed. In order to increase the link throughput of real-time services, in this paper, we investigate the performance of the SANET with the spatial transmit diversity techniques are employed. Based on the analysis of the packet error rate and throughput, we select the efficient multiple antenna schemes for SANET to improve the link reliability.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.121.2-121
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• 2001

Many of today´s robot are required to perform tasks which demand a high level of accuracy in end-effector positioning. Those rigid robots are very inefficient and slow because its have large and heavy links, In an attempt to solve these problems, a robots using flexible beam were created. But the single-link flexible beam is infinite-dimensional system. Many researchers have proposed controlling such a beam an approximated model consisting of a finite a number of models. In this paper, we start by deriving the analytic model for the dynamics of general single-link beam, and a controller is designed for flexible beam with integral type servo system bases of the linear matrix inequality (LM) technique. To the end, simulation results show that a designed controller guarantees affective vibration control the single-link flexible beam.

• 한국통신학회논문지
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• 제21권6호
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• pp.1501-1509
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• 1996

Mobile stations can be classified by the transmission power level in CDMA system. Different performance parameters will be given to each class of mobile stations so that the appropriate quality ofservices can be provided. In this paper, it is assumed that there are two clsses of mobile stations. with the classification of mobile stations, analytical models are presented for the estimates of the reverse link capacity and the blocking probability. From the model for the reverse link capacity, the maximum number of each class of mobile stations to be served is derived. It is shown that $E_{b/}$I reduction of 1 dB allows the capacity to be increased by 25% and the data transmission rate and the power control accuracy have a significant effect on the reverse link capacity and the blocking probability. Simulation results are provided for validating the anlaytical estimates of the blocking probability.ocking probability.y.

• Journal of Communications and Networks
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• 제10권3호
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• pp.351-361
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• 2008

This paper presents a delay-margin based traffic engineering (TE) approach to provide end-to-end quality of service (QoS) in multi-protocol label switching (MPLS) networks using differentiated services (DiffServ) at the link level. The TE, including delay, class, and route assignments, is formulated as a nonlinear optimization problem reflecting the inter-class and inter-link dependency introduced by DiffServ and end-to-end QoS requirements. Three algorithms are used to provide a solution to the problem: The first two, centralized offline route configuration and link-class delay assignment, operate in the convex areas of the feasible region to consecutively reduce the objective function using a per-link per-class decomposition of the objective function gradient. The third one is a heuristic that promotes/demotes connections at different links in order to deal with concave areas that may be produced by a trunk route usage of more than one class on a given link. Approximations of the three algorithms suitable for on-line distributed TE operation are also derived. Simulation is used to show that proposed approach can increase the number of users while maintaining end-to-end QoS requirements.