• 제목/요약/키워드: period error

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An Improved Fuzzy Logic-based Adaptive PWM Technique (퍼지 논리를 기반으로 하는 개선된 적용 PWM 기법)

  • Moon, Hyoung-Soo;Han, Woo-Yong;Kim, Sung-Jung;Lee, Gong-Hee
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1084-1087
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    • 2002
  • This paper presents an improved fuzzy logic-based adaptive PWM technique. A fuzzy logic- based adaptive PWM technique determines the optimal output voltage vector which takes into account both direction of back-emf and direction of current error vector. This technique has a simple structure and a good level of stability, but it has disadvantages. The longer sampling period, the larger current error. Because there is no considerations of the current error magnitude of each phases. The proposed method improves the control performance by selecting the optimum switching pattern in which the magnitudes of current errors are considered introducing space vector concept. Simulation results using Matlab/Simulink show that the proposed control method reduces current error keeping the merit of previous one.

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A Study on Error of Frequence Rainfall Estimates Using Random Variate (무작위변량을 이용한 강우빈도분석시 내외삽오차에 관한 연구)

  • Chai, Han Kyu;Eam, Ki Ok
    • Journal of Industrial Technology
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    • v.20 no.A
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    • pp.159-167
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    • 2000
  • In the study rainfall frequency analysis attemped the many specific property data record duration it is differance from occur to error-term and probability ditribution of concern manifest. error-term analysis of method are fact sample data using method in other hand it is not appear to be fault that sample data of number to be small random variates. Therefore, day-rainfall data: to randomicity consider of this study sample data to the Monte Carlo method by randomize after data recode duration of form was choice method which compared an assumed maternal distribution from splitting frequency analysis consequence. In the conclusion, frequency analysis of chuncheon region rainfall appeared samll RMSE to the Gamma II distribution. In the rainfall frequency analysis estimate RMSE using random variates great transform, RMSE is appear that return period increasing little by little RMSE incresed and data number incresing to RMSE decreseing.

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Speeding-up for error back-propagation algorithm using micro-genetic algorithms (미소-유전 알고리듬을 이용한 오류 역전파 알고리듬의 학습 속도 개선 방법)

  • 강경운;최영길;심귀보;전홍태
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.853-858
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    • 1993
  • The error back-propagation(BP) algorithm is widely used for finding optimum weights of multi-layer neural networks. However, the critical drawback of the BP algorithm is its slow convergence of error. The major reason for this slow convergence is the premature saturation which is a phenomenon that the error of a neural network stays almost constant for some period time during learning. An inappropriate selections of initial weights cause each neuron to be trapped in the premature saturation state, which brings in slow convergence speed of the multi-layer neural network. In this paper, to overcome the above problem, Micro-Genetic algorithms(.mu.-GAs) which can allow to find the near-optimal values, are used to select the proper weights and slopes of activation function of neurons. The effectiveness of the proposed algorithms will be demonstrated by some computer simulations of two d.o.f planar robot manipulator.

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Equivalent Damping Ratio of the Inelastic SDOF Structures with Friction Damper (마찰감쇠기가 설치된 비선형 단자유도 건물의 등가감쇠비)

  • 김형섭;민경원;이상현;박지훈;문병욱
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.10a
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    • pp.492-499
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    • 2004
  • The purpose of this paper is to present a design procedure of coulomb friction dampers for controlling elastic and inelastic responses of building structures. The equivalent damping and frequency increased by the friction damper are estimated using ATC-40 and ATC-55 procedures which provide equivalent linear system for bilinear one, and then a design formula to achieve target performance response level by friction damper is presented. It is identified that there exists error between the responses obtained by this formula and by performing nonlinear analysis and the features of the error vary according to the hardening ratio, yield strength ratio, and structural period. Equations for compensating this er개r are reposed based on the least square method, and the results from numerical analyses indicate that the error is significantly reduced, and the proposed formula can be used without much error for designing coulomb friction damper for retrofitting a structure showing elastic or inelastic behavior.

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PD+I-type fuzzy controller using Simplified Indirect Inference Method

  • Kim, Ji-Hoon;Jeon, Hae-Jin;Chun, Kyung-Han;Park, Bong-Yeol
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.179.5-179
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    • 2001
  • Generally, while PD-type fuzzy controller has good performance in transient period, it has uniform steady state error of response. To improve limitations of PD-type fuzzy controller, we propose a new fuzzy controller to improve the performance of transient response and to eliminate the steady state error of response. In this paper, PD-type fuzzy controller is used a simplified indirect inference method(SIIM). When the SIIM is applied, the proposed method has the capability of the high speed inference and adapting with increasing the number of the fuzzy input variables easily. The outputs of this controller are the output calculated by PD-type fuzzy controller and the accumulated error scaling factor. Here, the accumulated error scaling factor is adjusted by fuzzy rule according to the system state variables. To show the usefulness of the proposed controller, it is applied to 0-type 2nd-order linear system.

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A Study on the Analysis and Prevention of the Human-related Marine Accidents (인적 요인을 중심으로 한 해양사고 분석 및 예방 연구 (예부선 사고사례를 중심으로))

  • Kim, Hong-Tae;Na, Sung
    • Journal of Korea Ship Safrty Technology Authority
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    • s.27
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    • pp.25-36
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    • 2009
  • Despite the development of the various navigational equipment, such as GPS, ARPA, ECDIS, AIS, VDR, and hull monitoring system, marine accidents are still a leading concern in shipping industry. For all accidents over the reporting period, approximately 60 to 80% of the accidents was involved in human error. It means that in each case, some events which were associated with human error initiated an accident, and those failures of human performance led to the failure to avoid an accident or mitigate it's consequences. However, the improvement and the effort on the maritime human error are still limited in an elementary step. The objective of this paper is to propose a modified Human Factors Analysis and Classification System (HFACS) model in order to analyse the collision accidents of tug-barge ship.

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A Case Study On The Suitability Of Drawings Through Application Of BIM In Construction Management (건설사업관리 분야에서 BIM적용을 통한 도서의 적합성 검토 사례)

  • Park, Young-Jin;Song, Kyung-Chul
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.33-34
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    • 2017
  • The purpose of this case study is to reduce the flaw and reconstruction occur at the level of construction by determining the propriety of estimate and error on a drawing and specification at working design level through case studies of BIM application at the level of design review. As a preliminary to apply BIM technology, it is needed to review the drawing, and then it is required to define BIM range by selecting the section in which construction error occurs frequently except for the type of part that is constructed repeatedly. At the execution level, the drawing is reviewed vertically, horizontally and spatially by proceeding structure and finish modeling on the defined BIM range, and also the propriety of estimate and error on the drawing and specification are examined. We aim to raise the completion rate, improve quality of construction, reduce the cost for construction and shorten period of construction by preparing for the error on the drawing and specification in advance through this review procedures.

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Sound Intensity Estimation with the Effect of Leakage Error from the Contaminated Data (누설오차의 영향을 고려한 음향 인텐시티의 추정)

  • 안세진;정의봉;정호경
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1189-1194
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    • 2002
  • Acoustic intensity is usually estimated by the cross-spectrum of acoustic pressure at two adjacent micrphones. The cross-spectrum calculated by digital Fourier transform technique will unavoidally have leakage error since the period of signal will not be usually coincident with record length. Therefore, the acoustic intensity estimated by the conventional r]n analyzer will show distorted value. In this paper the expression of the Fourier transformed data of a harmonic signal is formulated when there is leakage error. The method to elimate the effect of leakage error from the contaminated data is also proposed. Some numerical examples show the validation of the proposed method.

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A High Speed Distance Relaying Algorithm Based on a Least Square Error Method (최소자승법을 이용한 고속 거리계전 알고리즘)

  • Gang, Sang-Hui;Gwon, Tae-Won
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.7
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    • pp.855-862
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    • 1999
  • A high speed digital distance relaying algorithm based on a least square error method is proposed. To obtain stable phasor values very quickly, first, a lowpass filter which has very short transient period and no overshoot is presented. Secondly, the least square error method having the data window of 3 samples is used by applying a FIR filter which removes the DC-offset component in current relaying signals. Test results show that the proposed distance relaying algorithm detects most of internal faults within a half cycle after faults in a 154[kV] overhead transmission line system.

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A novel phase error predictor for servo system in home-use VCRs (가정용 VCR의 서보 시스템을 위한 새로운 위상 오차 예측기)

  • 이상락;박정배;유지윤;박귀태;신영후
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.45 no.4
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    • pp.530-534
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    • 1996
  • A novel phase error predictor is proposed for servo system in home-use VCRs. The multirate system in VCRs is converted into a single period sampling system with faster sampling time by using the proposed novel phase error predictor. And the disturbances can be measured much faster. From the experimental results, we can see that the perfomance of the control system is improved greatly. The phase lock time of the proposed servo system is ten times faster than that of the conventional system.

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