• 제어로봇시스템학회논문지
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• 제12권7호
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• pp.644-649
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• 2006

In this paper, a methodology for estimating the model parameters of a discrete-time system and tuning a digital PID controller based on the estimated model and a genetic algorithm is presented. To deal with optimization problems regarding parameter estimation and controller tuning, pseudo-parallel genetic algorithms(PPGAs) are used. The parameters of a discrete-time system are estimated using both the model adjustment technique and a PPGA. The digital PID controller is described by the pulse transfer function and then its three gains are tuned based on both the model reference technique and another PPGA. A set of experimental works on two processes are carried out to illustrate the performance of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.305-308
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• 2002

Because the digital control includes microprocessor different from an analog control, the digital control enables to monitor internal parameters of DC-DC converter and to control output voltage remotely by communicating with a Window based PC and also to monitor whether exact voltage is output or not. These things are impossible in an analog control. In this paper, a simple buck converter controlled by DSP is implemented. This converter outputs 0V to 5V from 15V input voltage and is controlled by a PD algorithm using DSP(TMS320C31). Finally the response characteristics of a step reference voltage and a digital controlled converter are analyzed to verify the usefulness of this converter.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2005년도 학술대회
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• pp.249-254
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• 2005

본 논문은 디지털 방송 프로그램 진행 중 비디오의 특정 시점에 동기화된 특정 객체의 위치정보를 표현하는 data stream을 생성하고, 그 시점에 해당 위치 정보를 해석하는 해석기에 관한 것이다. 현재의 상용 스트림 생성기는 디지털 방송 표준에서 권고하는 스트림 이벤트의 발생 시각과 셋톱박스에서 디코딩 시에 사용할 참조값을 적절하게 생성하지 못하고 있다. 또한, 셋톱박스에서 동작하는 애플리케이션(Xlet) 역시 STC(System Time Clock), PCR(Program Clock Reference), NPT(Normal Play Time) 등의 시간값을 적절하게 읽어내지 못하고 있다. 더욱이, 현재의 디지털 방송 표준에서는 영상 내 특정 객체를 위해 정보를 제공하는 데에는 한계가 있다. 따라서, 본 논문에서는 다양한 연동형 디지털 방송 프로그램 제작을 위해 비디오의 특정 시점에 동기화된 객체의 위치정보를 표현하는 data stream을 생성하는 방법과, 동기화된 데이터를 처리하는 애플리케이션에 대해서 설명한다.

• International Journal of Knowledge Content Development & Technology
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• 제3권1호
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• pp.31-63
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• 2013

The goal of this study is to improve the competitiveness of professional librarians in society. To this end, we analyzed domestic and international LIS curriculum, determined demand from field librarians through a survey, carried out job analysis by library types, and developed an operating model for LIS curriculum by synthesizing all of these results. Finally, we suggested a course of study for civil service librarians based on this model. As a result, the six required courses for civil service librarians are: Introduction to Library and Information Science, Information Organization, Information Services (Reference and Information Services), Library Management, Information Retrieval, and Field Work. The four core courses for the civil service concentration are: Collection Development, Information Sources by Subjects, Public Library Management, and Digital Libraries. Suggested electives best suited to this career path include Using Web Resources, Information Literacy, Information Services in Culturally Diverse Communities, Library Marketing, Libraries and Cultural Programs, Reading Guidance, Library History, Small Library Management, Studies in Library Buildings, Library Cooperation, Managing Digital Collections, and Information and Communication in a Digital Age.

• ETRI Journal
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• 제29권1호
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• pp.99-102
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• 2007

The channel level difference (CLD) is a main parameter in the reference model 0 (RM0) for MPEG Surround. Nevertheless, the CLD quantization method in the RM0 has problems such as the lack of theoretical background and inappropriate quantization levels. In this letter, a new CLD quantization method is proposed based on the virtual source location information which has strength in the quantization process. From experimental results, it is confirmed that the proposed scheme greatly reduces the quantization distortions measured in dB and degrees without any additional complexity.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1571-1574
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• 2002

This paper describes a circuit and its operations of a programmable digital on-chip terminator designed with CMOS circuits which are used in high speed I/O interface. The on-chip terminator matches external reference resistor with the accuracy of ${\pm}$ 4.1％ over process, voltage and temperature variation. The digital impedance codes are generated in programmable impedance controller (PIC), and the codes are sent to terminator transistor arrays at input pads serially to reduce the number of signal lines. The transistor array is thermometer-coded to reduce impedance glitches during code update and it is segmented to two different blocks of thermometer-coded transistor arrays to reduce the number of transistors. The terminator impedance is periodically updated during hold time to minimize inter-symbol interferences.

• 대한전자공학회논문지SP
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• 제45권5호
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• pp.18-24
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• 2008

본 논문은 적웅적 움직임 추정영역 선택을 사용한 디지털 영상안정화의 성능개선에 대한 새로운 방법을 제시한다. 움직임 추정을 위한 후보영역을 선정하고 그 중에서 제안하는 두 가지 방법인 다중 영상 참조와 윤곽에너지 판별을 통해 최종 움직임 추정영역을 선택한다. 정해진 영역에서 움직임을 추정하고 보상한다. 실험을 통해 제안하는 방법이 영상안정화의 성능을 향상 시킴을 보인다.

• Journal of electromagnetic engineering and science
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• 제17권1호
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• pp.39-43
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• 2017

In this paper, a systematic and statistical calibration technique was implemented to calibrate a high-speed signal converting system containing multiple digital-to-analog converters (DACs). The systematic error (especially the imbalance between DACs) in the current combining network of the multi-DAC system was modeled and corrected by calculating the path coefficients for individual DACs with wideband reference signals. Furthermore, by applying a Kalman filter to suppress noise from quantization and clock jitter, accurate coefficients with minimum noise were identified. For correcting an arbitrary waveform generator with two DACs, a co-simulation platform was implemented to estimate the system degradation and its corrected performance. Simulation results showed that after correction with 4.8 Gbps QAM signal, the signal-to-noise-ratio improved by approximately 4.5 dB and the error-vector-magnitude improved from 4.1% to 1.12% over 0.96 GHz bandwidth.

• 전기전자학회논문지
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• 제19권2호
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• pp.176-185
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• 2015

The study aims to a design hybrid frequency synthesizer in spectrum analyzer and to propose new techniques designed for evasion of in-band spurious. The study focuses on calculating the exact location of multiple phase locked loop of hybrid frequency synthesizer and spurious of direct digital synthesizer to evade in-band spurious outside of frequency range that the user wants to see and thereby simulating technique to improve input related spurious of spectrum analyzer for algorithm. The proposed technique is designed to calculate spurious evasion algorithm in central processing system when in-band spurious arises, and to move output frequency of DDS(direct digital synthesizer) into the place where no in-band spurious exists thereby improving performance of frequency synthesizer. The study used simulation and result representation to prove the effectiveness of the proposed technique.

• 전기학회논문지P
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• 제51권1호
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• pp.10-17
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• 2002

Due to the development of information communication field, the interest of the SMPS(Switched Mode Power Supply) is increased. The size and weight of SMPS are decided by inductor, capacitor and transformer. Thus, the low loss converter which is operated in high speed switching is required. The resonant FB DC-DC converter is able to operate in high speed switching and apply to high power field because the switching loss is low. In this thesis, it is proposed to control strategy for constant output power of resonant FB DC-DC converter in variable input voltage. The proposed control system is a digital I-PD type control and apply to phase-shift resonant type controller. The output voltage tracks reference without steady state error in variable input voltage. The validity of proposed control strategy is verified from results of simulation and experiment.