• ETRI Journal
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• 제24권2호
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• pp.69-81
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• 2002

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP-centric signaling and control architecture based on the generalized multi-protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross-connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS-based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user-network interface and network-network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to generalized MPLS signaling.

• ETRI Journal
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• 제29권1호
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• pp.79-88
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• 2007

This paper proposes a novel concept of adjusting the hardware size in a multi-carrier code division multiple access (MC-CDMA) receiver in real time as per the channel parameters such as delay spread, signal-to-noise ratio, transmission rate, and Doppler frequency. The fast Fourier transform (FFT) or inverse FFT (IFFT) size in orthogonal frequency division multiplexing (OFDM)/MC-CDMA transceivers varies from 1024 points to 16 points. Two low-power reconfigurable radix-4 256-point FFT processor architectures are proposed that can also be dynamically configured as 64-point and 16-point as per the channel parameters to prove the concept. By tailoring the clock of the higher FFT stages for longer FFTs and switching to shorter FFTs from longer FFTs, significant power saving is achieved. In addition, two 256 sub-carrier MC-CDMA receiver architectures are proposed which can also be configured for 64 sub-carriers in real time to prove the feasibility of the concept over the whole receiver.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.529-532
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• 2000

This paper addresses how to be connected with end-to-end shortcut using ATM Switched Virtual Connection (SVC) in ATM-based Multi-Protocol Label Switching (MPLS) Networks. Without additionally existing ATM Ships-in-the-Night (SIN) mode, when the stream is continuously transmitted at the same destination with the lapse of determined aging time, the connection is changed with end-to-end shortcut connection using ATM signaling. An ATM direct short circuit is performed an IP and ATM effective integration. An ATM shortcut has a number of advantages, like higher throughput, shorter end-to-end delay, reduced router load, better utilization of L2 Quality of Service (QoS) capabilities, and route optimization. In particular between other MPLS domains, this can be efficiently improved the performance of networks.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.192-200
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• 2011

This paper proposes a new modeling method for estimating the impedance of an on-chip power/ground meshed plane. Frequency dependent R, L, and C parameters are extracted based on the proposed method so that the model can be applied from DC to high frequencies. The meshed plane model is composed of two parts: coplanar multi strip (CMS) and conductor-backed CMS. The conformal mapping technique and the scaled conductivity concept are used for accurate modeling of the CMS. The developed microstrip approach is applied to model the conductor-backed CMS. The proposed modeling method has been successfully verified by comparing the impedance of RLC circuit based on extracted parameters and the simulated impedance using a 3D-field solver.

• Journal of Power Electronics
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• 제13권1호
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• pp.77-85
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• 2013

This paper proposes a new dead time compensation method of independent six-phase permanent magnet synchronous motors (IS-PMSM). The current of the independent phase machines contains odd-numbered harmonics because of the dead time and the nonlinear characteristics of the switching devices. By using the d-q-n three-dimensional vector analysis, these harmonics can be extracted at the n-axis current. Thus, the current distortion can be compensated by controlling the n-axis current of the IS-PMSM to zero. The proposed method is simple and can be easily implemented without additional hardware setup. The validity of the proposed compensation method is verified with simulations and several experiments.

• 대한전기학회논문지
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• 제38권9호
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• pp.671-683
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• 1989

A controller of interconnected power systems is investigated using an optimal multidimensional variable structure control. The switching hyperplane of the variable structure stabilizer is obtained by minimizing a quadratic performance index in continuous-time. A special feature of the optimal multidimensional variable structure stabilizer is that, when it is operated in the so-called sliding mode, the system response becomes insensitive to changes in the plant parameters. A digital simulation is performed by a digital computer using the Advanced Continuous Simulation Language (ACSL) package, which shows that the dynamic performance of the power system in response to mechanical torque changes is improved when optimal multidimensional variable sturcture stabilizers are employed.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2000년도 추계학술발표논문집 (하)
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• pp.1059-1062
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• 2000

MPLS(Multi-protocol Label Switching)는 차세대 인터넷(NGI : Next Generation Internet)에서 중계 망 구성을 위한 핵심기술로서 사용되고 있다. MPLS는 다양한 계층 2기술을 수용하며, 계층 2 기술에 독립된 형태의 중계망 구성 기술을 제공한다. 실제 대규모의 MPLS 인터넷 중계망을 구성위해 MPLS의 성능 측정과 분석 그리고 분석 결과에 따른 관리 기능이 필요하다. 본 논문에서는 이러한 MPLS 기반의 인터넷 중계망의 성능 측정과 관리를 위한 MPLS OAM(Operation, Administration, and Maintenance)기능을 제안하고 OPNET을 기반으로 한 시뮬레이션 모델로 구현하여 제안한 기능을 검증한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.540-541
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• 2013

본 논문에서는 PSCAD/EMTDC를 이용하여 MMC(Modular Multi-level Converter)를 기반으로 한 HVDC 시스템 시뮬레이션 모델을 개발하였다. 스위칭 레벨의 동작을 분석하기 위해 각 ARM당 10개의 SM(Sub-Module)과 2개의 RM(Redundancy-Module)을 구성하여 11-level의 MMC 출력 전압을 형성하였다. SM 동작시 발생하는 전압 불균등 문제를 해결하기 위하여 밸런싱 알고리즘을 적용하였으며, SM의 출력 전압에 발생하는 Ripple을 고려하여 Capacitor의 용량을 설계하고 이를 검증하였다. 또한 시뮬레이션을 이용하여 HVDC 성능 분석과 MMC의 성능개선을 위한 순환전류 알고리즘 및 Redundancy 투입 알고리즘을 구현하고 그 결과를 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.331-332
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• 2013

본 논문은 기존의 수동소자만을 가지는 LED 구동회로 동작 시 상용전원인 입력전압 변동에도 정적으로 LED 전력을 제어하는 LED 구동회로를 제안한다. 패시브 구동회로에서 입력전압이 변동할 경우 LED에서 소모되는 전력이 변동하는 문제를 해결하고자, 제안된 다단 스위칭 회로를 이용하여 LED의 개수를 조절함으로써 LED 전력을 일정한 범위 내에 동작하도록 제어하였다. 실험결과 입력전압대비 LED 전력변동률 $dP_o/dv_s$는 0.26임을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1336-1338
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• 2000

This paper proposed the single phase multi-level PWM AC/DC converter using binary combine which controls input current by combining buck converters to improve input current characteristic, and confirmed its validity throughout simulation and experiment. This method, which is multiplying and duplicating output of converter of equal capacity, has the advantage of being able to control unit power factor of input current and reducing of the problem caused by high frequency switching, and appling to high power converter because filter is not necessary etc.