• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.98-106
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• 1994

To realize high accuracy and high speed we developed a new self compensation scheme and applied it to a 10-bit D/A converter. This circuit can compensate the device mismatch without interrupting the D/A converter operation. With the compensation circuit,INA decreased down to 0.22LSB from 0.47LSB. The device was fabricated using a 0.8$\mu$m CMOS process. The area of the D/A converter core is 3.2mm$^{2}$ and the area of the compensation part is 0.64mm$^{2}$.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.105-106
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• 2014

본 논문에서는 대용량 푸시 전송을 위한 효율적인 아키텍처를 제안한다. MINA 프레임워크 상에서 XMPP 프로토콜을 이용한 푸시 전송은 세션이 연결된 환경에서 실시간 메시지를 전달하는 기술로 최근 푸시 전송 서버에서 많이 활용되고 있다. 하지만 웹 어플리케이션에서 전송함에 있어 WAS위에 푸시 모듈이 위치함으로 서버의 메모리 사용량이 오버로드 되는 부담을 안고 있다. 따라서 본 논문에서 제안하는 아키텍처는 서버를 이중화 하여 WAS와 MINA를 분리시켜 하나의 서버가 감당해야 하는 메모리 사용량을 감소 시키도록 하며 멀티큐와 프록시를 사용하여 대량의 푸시 전송시의 메시지 큐의 병목형상을 해결하고자 한다.

• The Korean Journal of Zoology
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• v.35 no.1
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• pp.87-95
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• 1992

한국의 세 섬집단으로부터 채집한 Drosophila melanogaster를 대상으로 465개의 haploid genome을 추출한 후, 제 2염색체 상에 위치한 Gpdh와 각서 유전자 및 In(2I)t의 빈도를 조사하여 이들간의 연관관계를 분석한 결과 Gpdh와 Adh 효소 좌위 사이 에 유의 한 연관 불평형 이 제주도와 울릉도집 단에서 관찰되었으며 , Gpdh와 In(2I)t, Adh와 In(21)t 사이에 모두 유의한 연관 불평형이 제주도, 영종도 그리고 울릉도집단에서 관찰되었다. 조사된 전체 genome들 중에서 In(21)t 를 가지고 있는 염색체의 98%(48/49)가 Gpdhf와 Adhs형으로 연관된 결과를 보였다. 이러한 결과들로 볼 때 이들 효소 좌위 사이에 나타난 연관 불평형은 In(21)t와의 hitchhiking현상에 의해 나타난 결과로 해석되며 본 섬집단에서 그 정도가 더 심한 것으로 확인되었다.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.8
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• pp.742-747
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• 2004

Outdoors we can easily acquire our accurate location by GPS. However, the GPS signal can't be acquired indoors because of its weak signal power level. Adequate positioning method is demanded for many indoor positioning applications. At present, wireless local area network (WLAN) is widely installed in various areas such as airport, campus, and park. This paper proposes a positioning algorithm using WLAN signal strength to provide the position of the WLAN user indoors. There are two methods for WLAN based positioning, the signal propagation method uses signal strength model over space and the empirical method uses RF power propagation database. The proposed method uses the probability distribution of the power propagation and the maximum likelihood estimation (MLE) algorithm based on power strength DB. Test results show that the proposed method can provide reasonably accurate position information.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.489-495
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• 2003

A high performance and low noise refrigerator fan has been developed in order to satisfy the customer's high quality needs, that is, luxury, big size and low noise. In this study, the characteristics of a new developed fan and a current fan was calculated and compared by using numerical simulation. Rotation of a fan makes cold air circulation inside a refrigerator. A numerical simulation of air flow shows distribution and local flow regime of a cold air flow circulation, and revealed a cause of low noise as well. Optimization of a duct shape also decreased noise level.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.2
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• pp.175-184
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• 1996

In this paper the newly developed discrete-time adaptive sliding mode control method is proposed and applied to the power system stabilization problem. In contrast to the conventional continuous-time sliding mode controller, the proposed method is developed in the discrete-time domain and based on the input/output measurements instead of the continuous-time and the full-states feedback, respectively. Because the proposed control method has the adaptivity property in addition to the natural robustness property of the sliding mode control, it is possible to design the power system stabilizer which can overcome both the minor variations of the parameters of the power system and the diverse operating conditions and faults of the power system. Mathematical proof and the various computer simulations are done to verify the performance and stability of the proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1902-1910
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• 2009

This paper presents a graphical windows-based program for the education and training for novel network reduction. The object of developed simulator is to provide users with a simple and useable tool for gaining an intuitive feel for power system analysis. The developed simulator consists of the main module (MMI,GUI), the location marginal price module (LMP), the clustering module and network reduction module. Each module has a separate graphical and interactive interfacing window. The developed simulator needs with the PSS/E input data format, generator cost function, location information. Line admittances of reduced network was determined by using the power flow method(Newton-Raphson). So line flow of reduced network is almost same to original power system. Results of reduced network are compared on the window in the tabular format. Therefore, the developed simulator can be utilized as a useful tool for effective education and training for power system analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.69-72
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• 2001

A novel water-turbine, Katamax, for micro hydropower generator is proposed, which has reasonable efficiency even in two meters of water head. The basic concept of Katamax is similar to that of waterwheel except that Katamax has two axis on which the blades rotate, where general waterwheel has only one. Brief structure and principles of Katamax are explained and analysis for efficiency of each module are provided. The result of the prototype product of Katamax is briefly explained.

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.09a
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• pp.90-90
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• 2019

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.175-177
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• 1999

This paper presents a prototype of visualization MMI of the Power System Phenomenon, specially synchronous machine dynamics and frequency deviations of power system for KEPCO's Enhanced Power System Simulator(KEPS)[1]. And some visualization designs of the Power System Phenomenons such as voltage stability, transient stability, SSR, Line overflow, and voltage deviations are presented. The prototype MMI has included the animations & 3D graphics presentations for synchronous machine rotor deviations and frequency deviations. So, a user can intuitively acquire the basic concepts of the power system oscillations. Finally, it will be scheduled to development of the various visualization MMI of the power system phenomenons for development and installation of KEPS.