• 전자공학회논문지
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• 제50권6호
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• pp.114-121
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• 2013

BTC 영상 압축은 간단하고, 하드웨어 구현이 용이하여, LCD의 오버드라이브에 필요한 영상 압축 기법으로 널리 사용되어지고 있다. 본 논문에서는 압축 손실을 줄이기 위한 방법으로, MLQ-BTC (Multi-Level Quantization BTC) 알고리즘을 제안한다. MLQ-BTC 알고리즘은 입력 영상을 Quasi 8-level BTC 방법과 Advanced 2-level BTC 방법으로 압축 및 복원하여, 압축손실이 적은 알고리즘을 선택하는 과정이다. 시뮬레이션으로 기존의 BTC 알고리즘과 PSNR 및 압축비율의 비교를 통해서, 제안한 알고리즘의 효율성을 확인하였다.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 1998년도 공동추계학술대회 경제위기 극복을 위한 정보기술의 효율적 활용
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• pp.827-834
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• 1998

This paper describes a multi-level simulation technique and its implementation, which accurately solve voltages and currents of circuits descreibed at mixed levels of abstractions. A metho to form a tightly coupled simulation environment is proposed and, starting from a description of a circuit, simulation set-up and analysis procedure of the multi-level simulator for a transient response are presented. Circuit and behavioral simulation techniques and their implementations composing the multi-level simulation are explained in detail. Most of the algorithms implemented in the simulation are based upon the standard simulation techniques in order to obtain the reliability and accuracy of conventinoal simulators. Simulation examples show that the multi-level simulator can analyze circuits containing highly nonlinear behavioral models without loss of accuracy provided the behavioral models are accurate enough.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.100-102
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• 2007

In this paper, a modified multi-level convert for low cost high speed switched reluctance (SR) drive is proposed The proposed multi-level converter has reduced number of power switches and diodes than that of a conventional asymmetric converter for SRM, and lower voltage rating of the dump capacitor comparing with energy efficient c-dump converter. It can supply five operating modes that is boosted, DC-link, zero, negative bias and negative boosted voltage. The proposed multi-level converter has fast excitation and demagnetization modes of phase current, so dynamic response can be achieved. The proposed multi-level converter is verified by computer simulation and experimental results.

• Journal of Power Electronics
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• 제14권6호
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• pp.1093-1099
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• 2014

This paper proposes a power conversion topology involving a multi-winding transformer and converters. The fundamental idea is described with circuit diagrams, and the voltage output of the proposed topology is analyzed mathematically. The effectiveness of the topology is discussed with test results from a small-scale power conversion system. When conventional hardware consisting of two-level converters and a transformer is employed, multi-level voltage outputs can be applied to the transformer windings by the proposed method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.75-77
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• 2006

본 논문에서는 PDP 구동 응용을 위한 간단한 구조의 Multi-level 유지 방전 회로를 제안한다. 제안된 회로는 기존의 Multi-level 유지 방전 회로에 비해 적은 수의 스위칭 소자로 구현할 수 있어 간단한 구조를 가진다. 또한, 기존의 Multi-level 회로와 동일한 수준의 소자 전압 및 전류 스트레스를 가지므로, 저가의 고성능의 저전압 소자를 사용할 수 있어 PDP 구동 회로의 원가 저감과 고효율 동작을 이룰 수 있을 것으로 예상한다. 제안된 회로의 동작 원리를 설명하고, 42" HD급 PDP에 실제 적용 실험을 하여 제안된 회로의 우수성을 보인다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.333-342
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• 1999

An improved optimization algorithm for multi-objective and multi-level (MO/ML) optimum design of steel frames is proposed in this paper. In order to optimize the steel frames under seismic load, two main objective functions need to be considered for minimizing the structural weight and maximizing the strain energy. For the efficiency of the proposed method, well known multi-level optimization techniques using decomposition method that separately utilizes both system-level and element-level optimizations and an artificial constraint deletion technique are incorporated in the algorithm. And also dynamic analysis is executed to evaluate the implicit function of structural strain energy at each iteration step. To save the numerical efforts, an efficient reanalysis technique through sensitivity analysis of dynamic properties is unposed in the paper. The efficiency and robustness of the improved MOML algorithm, compared with a plain MOML algorithm, is successfully demonstrated in the numerical examples.

• 대한산업공학회지
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• 제43권2호
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• pp.135-146
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• 2017

This paper considers redundancy optimization problems of multi-level systems and reviews existing papers which proposed various optimization models and used different algorithms in this research area. Three different mathematical models are studied: Multi-level redundancy allocation (MRAP), multiple multi-level redundancy allocation, and availability-based MRAP models. Many meta-heuristics are applied to find optimal solutions in the several optimization problems. We summarized key idea of meta-heuristics applied to the existing MARP problems. Two extended models (MRAP with interval reliability of units and an integrated optimization problem of MRAP and preventive maintenance) are studied and further research ideas are discussed.

• 정보보호학회논문지
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• 제16권6호
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• pp.163-167
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• 2006

멀티-레벨 ${\mu}TESLA$는 다수의 키 체인을 이용하여 ${\mu}TESLA$를 긴 수명의 센서 네트워크에 효율적으로 확장시킨 프로토콜이다. 본 논문에서는 멀티-레벨 ${\mu}TESLA$의 변형으로 하위 키체인 초기값의 즉시 인증이 가능한 새로운 멀티-레벨 ${\mu}TESLA$의 구성방안들을 제안한다. 제안방식들은 원래의 멀티-레벨 ${\mu}TESLA$의 즉시 인증 가능한 변형에 비해 계산/통신 효율성이나 패킷 분실에 대한 저항성 등 모든 면에서 보다 우수한 특성을 제공한다.

• 한국군사과학기술학회지
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• 제13권4호
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• pp.673-682
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• 2010

This paper describes and analyzes a various generation methods of the mutually orthogonal polyphase sequences with low cross-correlation peak sidelobe and low autocorrelation peak sidelobe levels. The mutual orthogonality is the key requirement of multi-static or MIMO(Multi-Input Multi-Output) radar systems which provides the good target detection and tracking performance. The polyphase sequences, which are generated by SA(Simulated Annealing) and GA(Genetic Algorithm), have been analyzed with ACF(Autocorrelation Function) PSL(Peak Sidelobe Level) and CCF(Crosscorrelation Function) level at the matched filter output. Also, the ambiguity function has been introduced and simulated for comparing Doppler properties of each sequence. We have suggested the phase selection rule for applying multi-static or MIMO systems.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권3호
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• pp.112-118
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• 2001

In the near future, the voltage of power system for passenger vehicle will be changed to 42V from existing 14V./ Because of increasing power and voltage ratings used in the vehicle the motor drive system has high switching dv/dt and it generates electromagnetic interference (EMI) To solve these problems multi-level inverter system may be used The feature of multi-level inverter is the output voltage to be synthesized from several levels of voltage Because of this feature high switching dv/dt and EMI can be reduced in the multi-level inverter system But as the number of level is increased manufacturing cost is getting expensive and system size is getting large. Because of these disadvantages the application of multi-level inverter has been restricted only to high power drives. The method to reduce manufacturing cost and system size is to integrate circuit of multi-level inverter into a few chips But isolated power supply and signal isolation circuit using transformer or opto-coupler for drive circuit are obstacles to implement the integrated circuit (IC) In this paper a drive circuit of 4-level inverter suitable for integration to hybrid or one chip is proposed In the proposed drive circuit DC link voltage is used directly as the power source of each gate drive circuit NPN transistors and PNP transistors are used to isolate to transfer the control signals. So the proposed drive circuit needs no transformers and opto-couplers for electrical isolation of drive circuit and is constructed only using components to be implemented on a silicon wafer With th e proposed drive circuit 4- level inverter system will be possible to be implemented through integrated circuit technology Using the proposed drive circuit 4- level inverter system is constructed and the validity and characteristics of the proposed drive circuit are proved through the experiments.