• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.730-735
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• 2004

This paper describes what brings about DC offset and the impact or the DC offset on the performance or direct-conversion mobile receiver in WCDMA system. The performance degradation of $E_{b}/N_{o}$ due to the DC offset is presented through simulation result. Direct-conversion RF Transceiver which has the function of DC offset control is implemented and then applied to the WCDMA test-bed for the performance evaluation. The receiver performance degradation of $E_{c}/I_{o}$ is evaluated and analyzed by varying DC offset value. The practical test showed the minimum requirement of DC offset value to meet system performance.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1269-1272
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• 2001

EasySoft(이하:ES)는 컴퓨터를 처음 배우는 초급자에서부터 프로그래밍 가능자에 이르기까지 다양한 범위의 학습자에게 통합 교과적인 지식을 토대로 알고리즘 교육을 제공하여, 창의성과 논리성 계발의 효과를 거둘 수 있도록 만들어진 학습기자재이다. ES는 EasyLab, EasyC, Visual Basic과 같이 ActiveX를 지원하는 툴과 연동하여 사용한 수 있는 ActiveX 제어도구(EasyOCX)로 구성되어 있다. 학습자는 ES를 통하여 자신의 생각을 구성, 알고리즘화 시켜 프로그래밍하고 코드를 로봇으로 전송하여, 로봇의 움직임과 자신의 의도를 비교, 연구, 반복하는 작업으로 학습하게 된다. ES는 학습기자재가 부족한 교실현장에서 직접 활용할 수 있도록 구성된 것으로, 흥미적 요소와 교육적 요소를 적절하게 조화 시킨 소프트웨어이다. EasyLab은 컴퓨터를 모르는 학습자도 알기쉬운 GUI식 흐름도 기반 S/W를 표방하므로 초등학교에서, EasyOCX나 EasyC의 경우는 EasyLab과 유사한 방식을 추구하되 직접 프로그래밍 하게 되어있어 한 단계 높은 중 고등학교의 교수장면에서 직접 활용이 가능하다.

• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.52-57
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• 1999

It is very important to design of QAM modulator of high spectral efficiency for high speed data transmission. In this paper, typical 16-QAM modulator is designed by modification design of DDFS(direct digital frequency synthesizer). DDFS generates sinusoidal waveform digitally to the frequency setting word. Phase modulation is accuratly made by control of a generated phase increment value and amplitude modulation is accomplished in the D/A converter output by control of amplitude level. For the suppression of harmonics and glitch, dual-structured DDFS is studied to improve the spurious characteristics. P-Spice is used for design and simulation in mixed mode. Also we can get the satisfactory results of designed 16-QAM modulator from the constellation output.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.112-117
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• 1989

This paper describes to the unit rectangle EB direct writing lithography method using SEM. This method has the constant exposure time to any rectangle pattern. In order to change the EB current according to various rectangle size for the constant exposure time, the supply current of condenser lens in controlled by BITMAP-IV CAD system. By this method, the resizing procedure of density pattern area is not needed to pattern data conversion, and the through-put ofr exposure is increased about 172 times compared with the unit scan exposure method.

• Journal of the Korean Society for Library and Information Science
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• v.39 no.2
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• pp.35-55
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• 2005

This study attempts feasibility analysis of cataloging outsourcing. The economic analysis model based on information economics categorizes the benefit into direct benefit and value linking. We measure direct benefit by cost savings and cost avoidance, value linking by the degree of improvement in cataloging quality The results show that there is no feasibility overall, because librarians spent more time to control the quality due to vendor's lack of professionalism, resulting little effect on cost savings. When cataloging outsourcing is forcibly used under the economically infeasible condition, it is impossible to achieve the basic purpose of operating cost savings and improvement of service function.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.59-74
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• 2014

The social network service is a online service letting users express the personality and enhancing the human network. However, these features result in side effects which diffuse personal information and make users access to treacherous information. Therefore, various access control models have been proposed. However, the access control mechanisms which encrypt data are only able to be applied for controlling access from direct node, and the access control mechanisms without data encryption allow service provider to access all the information. Moreover, both mechanisms do not consider dynamic changes in reliability of the users. In this paper, we propose relationship-based dynamic access control model including encryption of sensitive data, which consider the characteristics of SNS and improves the security of SNS.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.9
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• pp.692-700
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• 2011

The use of electric field has been studied as an alternative for biofilm control dominated by disinfectants and antibiotics. This technology would be advantageous in the environmental respect that biofilm can be controlled based on electron transfer, not using chemical disinfectants and antibiotics. Control mechanisms which were reported by earlier studies are organized as; (1) bacterial adhesion control by electrostatic repulsion at a negative current, (2) bacterial adhesion control using bacterial motion and (3) bacterial inactivation by direct oxidation at a positive current, (4) bioelectric effect leading to biofilm inactivation. In this review article, we summarized the technologies for biofilm control using electric field and provided some application examples from previous studies.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.49-57
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• 2009

The camera electronics in the KOMPSAT-3 payload provides the several control clocks in order to move the charges, which are converted from the light in the pixel, in the vertical and horizontal direction. Generally, the control clocks depend on the CCD internal design in the system. The KOMPSAT-3 payload uses the CCD controlled by 3-phase vertical clocks and 4-phase timing. The camera generates the various clocks such as the vertical clocks, the horizontal clocks, the summing clocks, the reset clocks and so on. The vertical clocks are deeply related to the camera performance and synchronized with satellite scan-rate even though they are relatively slow. Also, it gives the horizontal clocks without distortion under the very fast pixel-rate. This paper shows the design and simulation of the CCD clocks driver for the KOMPSAT-3 payload.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.55-64
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• 1990

This paper concerned about a study on the direct pole placement PID self-tuning controller design for DC servo motor control system. The method of a direct pole placement self-tuning PID control for a DC servo motor of Robot manipulator tracks a reference velocity in spite of the parameters uncertainties in nonminimum phase system. In this scheme, the parameters of classical controller are estimated by the recursive least square (RLS)identification algorithm, the pole placement method and diophantine equation. A series of simulation in which minimum phase system and nonminimum phase system are subjected to a pattern of system parameter changes is presented to show some of the features of the proposed control algorithm. The proposed control algorithm which shown are effective for the practical application, and experiments of DC servo motor speed control for Robot manipulator by a microcomputer IBM-PC/AT are performed and the results are well suited.

• The Journal of the Acoustical Society of Korea
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• v.33 no.6
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• pp.375-382
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• 2014

In many practical active noise control applications, the primary noise contains multiple closely-spaced harmonics. A narrowband ANC system consists of adaptive filters excited by a composite reference signal, which is the set or sum of sinusoids. This paper analyzes and shows that the convergence speeds of the direct form, parallel form, and simplified parallel form narrowband ANC systems are affected by the fundamental frequency and frequency separation between two adjacent sinusoids in the reference signal. This paper also proposes the new simplified parallel form narrowband ANC system whose convergence speed is independent on the frequency of the reference signal. Computer simulations are conducted to verify the analysis presented in the paper and to compare the proposed narrowband ANC system with the conventional narrowband ANC system.