• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권1호
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• pp.43-48
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• 2010

This article presents the experimental studies of controlling angle and position of the inverted pendulum system using neural network to compensate for errors caused due to fuzzy controller. Although fuzzy control method can deal with nonlinearities of the system, fixed fuzzy rules may not work and result in tracking errors in some cases. First, a nominal Takagi-Sugeno (TS) type fuzzy controller with fixed weights is used for controlling the inverted pendulum system. Then the neural network is added at the reference input to form the reference compensation technique (RCT)control structure. Neural network modifies the input trajectories to improve system performances by updating internal weights in on-line fashion. The back-propagation learning algorithm for neural network is derived and used to update weights. Control hardware of a DSP 6713 board to have real time control is implemented. Experimental results of controlling inverted pendulum system are conducted and performances are compared.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권8호
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• pp.377-386
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• 2005

This paper presents the control algorithm of single-phase hybrid active power filter for the compensation of harmonic current components in nonlinear R-L load with passive active Power filters. To construct two phase system, an imaginary second phase was made. In this proposed method, the new signal which is the delayed through the filtering by the phase-delay property of low-pass filter is used as the secondary phase. Because two-phases have the different phase, the instantaneous calculation of harmonic current is possible. In this paper, a reference voltage is created by multiplying the coefficient k by the compensation current using the rotating reference frame synchronized with the source-frequency, not applying to instantaneous reactive power theory which has been used with the existing fixed reference frames In order to verify the validities of the proposed control methods, experiments are carried out with the prototypes of single-phase hybrid active power filter.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.177-180
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• 2006

This study is to make a basic study if solid zinc (Zn) can be used for buried reference electrode, so we examined the adequacy of zinc as reference electrode by using zinc which showed regular electrode for buried period. The deference of electric potential if zinc electrode for corrosion factor such as soil resistivity or pH didn't show fixed trend and there was no clear trend on the change of measurement period. From field test, it is known that the natural electric potential difference of CSE electrode and zinc electrode is 1,100mV, but the electric potential of zinc electrode for CSE electrode in the natural soil and copying soil was 1,094~1,158mV. There was no fixed trend on the change of measurement period and electric potential difference of zinc electrode for corrosion factors such as soil resistivity or pH. Consequently, there was 40~60mV of electric potential difference in every copying soil during the experiment measurement.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 추계학술발표회 논문집
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• pp.405-410
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• 2004

In mid-90's, the Korean government introduced the GIS(Geographic Information System) to digitalize every topography of national land and thereby, index locations and attributes of various urban facilities to construct a system whereby every information could be managed and operated in an integrated way, but the reliability of such geographic information has yet to be tested, much less its modification, complementation and maintenance. Under such circumstances, this study was aimed at constructing a reference point infrastructure for Seoul and Kyonggi area and comparing the data obtained from the GPS operation and various facility location data with the existing GIS data to address the problems of GIS operation and suggest their solutions. As a result of calculating the GPS reference point data and analyzing the deviations of the unknown point data in comparison with the fixed point ones, it was found that the horizontal location values were reliable within +/- 5cm, but that the above-sea level values varied as much as 1.4m depending on the deployment of pre-set fixed points determined by the direct level gauging. In addition, as a result of directly surveying major facilities around the roads based on the coordinates of the urban reference points networked with such a reference point system to check their conformity to existing data, it was confirmed that the difference was as wide as 2m. Such differences may be attributable to the fact that the data with their geographic information not confirmed are used as basic data for GIS. Hence, this study suggests the ways to set the absolute geographic data based on reference points and test the reliability of existing data and thereby, suggests a methods to solve the problems.

• 임상간호연구
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• 제23권1호
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• pp.54-63
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• 2017

Purpose: The purpose of this study was to compare the working status and Standard Shiftwork Index (SSI) between night shift-fixed nurses and rotating shift nurses. Methods: Participants were 367 nurses working as registered nurses at 7 different medical institutions. The data were collected from August 8, 2016 to September 30, 2016. Results: Night shift fixed nurses were more satisfied with work schedule than rotating shift nurses. Rotating shift nurses reported higher SSI scores, such as chronic fatigue, musculoskeletal problems, than night shift fixed nurses. In SSI's sub-items, rotating shift nurses reported higher scores, such as the amount of sleep, feeling well after sleep, heartburn or stomach-ache and heartbeat irregularities, than night shift fixed nurses. Conclusion: The results indicated that night shift fixed system might be an effective method to improve nurses' work satisfaction. It is necessary to figure out any suitable night shift fixed system based on the characteristics of each nursing organization. The SSI might be an useful tool to measure the nurses' satisfaction in reference to their work shift.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1183-1188
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• 2005

In this paper, we propose a 3D automated measuring system which measures the mandibular movements and the reference plane of the jaw movements. In diagnosis and treatment of the malocclusions, it is necessary to estimate the mandibular movements and the reference plane of the jaw movements. The proposed system is configured with double stereo-cameras, PC, two moving pattern plates(MPPs), two fixed pattern plates(FPPs) and one orbital marker. The virtual pattern plate is applied to calculate the homogeneous transformation matrices which describe the coordinates systems of the FPP and MPP with respect to the world coordinates system. To estimate the parameters of the hinge axis, the Euler's theorem is applied. The hinge axis points are intersections between the FPPs and the hinge axis. The coordinates of a hinge axis point with respect to the MPP coordinates system are set up to fixed value. And then, the paths of the jaw movement can be calculated by applying the homogeneous transformation matrix to fixed hinge axis point. To examine the accuracy of the measurements, experiments of measuring the hinge axis points and floating paths of them are performed using the jaw motion simulator. As results, the measurement errors of the hinge axis points are within reasonable boundary, and the floating paths are very similar to the simulator's moving path.

• 한국멀티미디어학회논문지
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• 제9권2호
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• pp.172-188
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• 2006

본 논문은 무선 센서 네트워크(wireless sensor network)에서 노드들의 위치 추정 문제를 다룬다. 위치 추정을 위한 기존의 기법들은 인접한 노드들 간의 거리를 이용하여 자신의 위치를 추정하는 LGB 기법과 멀리 떨어진 노드들 간의 거리를 추정하여 위치 추정에 이용하는 GGB 기법으로 분류할 수 있다. 그러나 LGB 기법의 경우 상대적으로 정확도가 낮은 거리 측정 기법 하에서는 적합하지 않은 면이 있고, 반면 GGB 기법의 경우 장애물이 있거나 혹은 노드들이 분포한 영역이 사각형이나 원형과 같은 정형이 아닌 경우에는 적용하기 어려운 면이 있다. 본 논문에서는 두 가지 기법을 절충하여 부정확한 거리 측정 기법 하에서 장애물이 있거나 비정형의 영역 내에 분포한 노드들에 대해서도 위치 추정을 가능하게 하는 새로운 위치 추정 알고리즘을 제안하고, 그 성능을 모의실험을 통해서 비교 분석한다.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제29권4호
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• pp.293-306
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• 2022

In the present paper, we introduce the notation of 𝛿-convex rectangular metric spaces with the help of convex structure. We investigate fixed point results concerning Kannan-type contraction and Reich-type contraction in such spaces. We also propound an ingenious example in reference of given new notion.

• 융합신호처리학회논문지
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• 제8권4호
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• pp.297-306
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• 2007

모델 기준 제어(MRC)는 플랜트가 주어진 기준 모델의 거동을 추종하도록 플랜트를 제어하는 제어 기법이다. 기준 모델은 플랜트가 추종할 이상적인 궤적을 제공한다. 지금까지 많은 종류의 MRC가 제안되었지만, 본 논문에서는 모델 기준 슬라이딩 모드 제어(MRSMC)에 대해 제어 대상 플랜트가 불확실성을 갖는 단일 입출력 2차 시변 선형 시스템인 경우에 대해 연구를 수행하였다. 본 논문에서 MRSMC를 위한 기준 모델의 설계 방법이 제안하였다. 제안된 방법은 제한된 제어 입력, 기준 입력, 시스템 파라미터에 대한 정보를 사용하여 기준 모델을 선정한다. 이러한 선정 결과는 고정된 기준 모델의 선정, 계단 입력 인가시의 가변 기준 모델 갱신, 매 샘플링 시간마다 순간 기준 모델의 갱신 등으로 이용할 수 있다. 모터의 위치 제어 시스템에 대한 시뮬레이션 결과는 제안된 방법의 효용성을 보여준다.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.94-100
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• 2008

This paper presents a new control method of single-phase active power filter (APF) for the compensation of harmonic current components in nonlinear loads. To facilitate the possibility of complex calculation for harmonic current detection of the single phase, a single-phase system that has two phases was constructed by including an imaginary second-phase giving time delay to the load current. The imaginary phase, which lagged the load current T/4 (Here T is the fundamental cycle) is used in the conventional method. But in this proposed method, the new signal as the second phase is delayed by the filter. Because this control method is applied to a single-phase system, an instantaneous calculation was developed by using the rotating reference frames synchronized to source-frequency rather than by applying instantaneous reactive power theory that uses the conventional fixed reference frames. The control scheme of single-phase APF for the current source with R-L loads is applied to a laboratory prototype to verify the proposed control method.