• Title/Summary/Keyword: Fast Computation

Search Result 750, Processing Time 0.036 seconds

Investigation and Simulation Study on the Cascading Trip-off Fault of a Large Number of Wind Turbines in China on May 14, 2012

  • Qiao, Ying;Lu, Zong-Xiang;Lu, Ji;Ruan, Jia-Yang;Wu, Lin-lin
    • Journal of Electrical Engineering and Technology
    • /
    • v.10 no.6
    • /
    • pp.2240-2248
    • /
    • 2015
  • The integration of the large-scale wind power brings great challenge to the stability of the power grid. This paper investigates and studies the fault on May 14, 2012 of the large-scale cascading trip-off of wind turbines in North China. According to the characteristics of the voltage variation, the fault process is divided into three stages: the pre-event stage, the critical stage before cascading, and the cascading stage. The scenes in the fault are reproduced, using the full-size actual power system model. Simulation models of double-fed induction generators (DFIGs) and SVCs including protection settings and controller strategies are carefully chosen to find out the reason of voltage instability in each stage. Some voltage dynamic that have never been observed before in the faults of the same kind are analyzed in detail, and an equivalent voltage sensitive dynamic model of DFIG is proposed for the fast computation. The conclusions about the voltage dynamics are validated by the actual PMU observation evidence.

A Study of Kinematic Selection and Design of Manipulator Aimed to Specified Task (작업지향형 매니퓰레이터 기구설계기법에 관한 연구)

  • Lee, Hee-Don;Yu, Seung-Nam;Ko, Kwang-Jin;Han, Chang-Soo
    • Proceedings of the KSME Conference
    • /
    • 2007.05a
    • /
    • pp.939-944
    • /
    • 2007
  • Generally, development of a robot capable of fast movements or high payloads is progressed by the analysis of dynamic characteristics, DOF positioning, actuator selection, structure of links, and so on. This paper highlights the design of a robot manipulator handled by a human for man-machine cooperation. The requirements of the proposed system include its having multi-DOF(Degree of Freedom)and the capacity for a high payload in the condition of its maximum reach. The primary investigation factors are motion range, performance within the motion area, and reliabilityduring the handling of heavy materials. Traditionally, the mechanical design of robots has been viewed as a problem of packaging motors and electronics into a reasonable structure. This process usually transpires with heavy reliance of designerexperience. Not surprisingly, the traditional design process contains no formally defined rules for achieving desirable results, as there is little opportunity for quantitative feedback during the formative stages. This work primarily focuses on the selection of proper joint types and link lengths, considering a specific task type and motion requirements of the heavy material handling.

  • PDF

Sound Source Localization and Separation for Emotional Robot (감성로봇을 위한 음원의 위치측정 및 분리)

  • 김경환;김연훈;곽윤근
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.20 no.5
    • /
    • pp.116-123
    • /
    • 2003
  • These days, the researches related with the emotional robots are actively investigated and in progress. And human language, expression, action etc. are merged in the emotional robot to understand the human emotion. However, there are so many sound sources and background noise around the robot, that the robots should be able to separate the mixture of these sound sources into the original sound sources, moreover to understand the meaning of voice of a specific person. Also they should be able to turn or move to the direction of a specific person to observe his expression or action effectively. Until now, the researches on the localization and separation of sound sources have been so theoretical and computative that real-time processing is hardly possible. In this reason for the practical emotional robot, fast computation should be realized by using simple principle. In this paper the methods for detecting the direction of sound sources by using the phase difference between peaks on spectrums, and the separating the sound sources by using fundamental frequency and its overtones of human voice, are proposed. Also by using these methods, it is shown that the effective and real-time localization and separation of sound sources in living room are possible.

Development of Efficient Numerical Method in Time-domain for Broadband Noise due to Turbulence-cascade Interaction (유입난류와 평판 캐스케이드 상호작용에 따른 광대역 소음 해석을 위한 효율적인 시간영역 수치기법의 개발)

  • Kim, Sang-Ho;Cheong, Cheol-Ung
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.19 no.7
    • /
    • pp.719-725
    • /
    • 2009
  • An efficient time-domain numerical method for the analysis of broadband noise generation and propagation due to turbulence-cascade interaction is developed. The core algorithm of the present method is based on the B-periodicity of the acoustic response function of the flat-airfoil cascade to the ingesting gust(B denotes the number of airfoils in the cascade). To confirm this periodicity, gust-cascade interaction problem are solved by using the time-domain method, which shows that the incident gust with the circumferential mode number having the same remainders when divided by the airfoil number excites the same acoustic response of the cascade. Using the proposed fast algorithm with this periodicity, we show that the total computation time for the model broadband problem using the total 525 incident gust modes can be reduced to about 1/4 of that taken in using the previous time-domain program.

Fast and Efficient Satellite Imagery Fusion Using DT-CWT Proportional and Wavelet Zero-Padding

  • Kim, Yong-Hyun;Oh, Jae-Hong;Kim, Yong-Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.33 no.6
    • /
    • pp.517-526
    • /
    • 2015
  • Among the various image fusion or pan-sharpening methods, those wavelet-based methods provide superior radiometric quality. However, the fusion processing is not only simple but also flexible, since many low- and high-frequency sub-bands are often produced in the wavelet domain. To address this issue, a novel DT-CWT (Dual-Tree Complex Wavelet Transform) proportional to the fusion method by a WZP (Wavelet Zero-Padding) is proposed. The proposed method produces a single high-frequency image in the spatial domain that is injected into the LRM (Low-Resolution Multispectral) image. Thus, a wavelet domain fusion can be simplified to spatial domain fusion. In addition, in the proposed DT-CWTP (DT-CWT Proportional) fusion method, it is unnecessary to decompose the LRM image by adopting WZP. The comparison indicates that the proposed fusion method is nearly five times faster than the DT-CWT with SW (Substitute-Wavelet) fusion method, meanwhile simultaneously maintaining the radiometric quality. The conducted experiments with WorldView-2 satellite images demonstrated promising results with the computation efficiency and fused image quality.

A Study on Kinematics Modeling and Motion Control Algorithm Development in Joint for Vertical Type Articulated Robot Arma (수직다관절형 아암의 운동학적 모델링 및 관절공간 모션제어에 관한 연구)

  • Jo, Sang-Young;Kim, Min-Seong;Yang, Jun-Seok;Won, Jong-Beom;Han, Sung-Hyun
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.19 no.1
    • /
    • pp.18-30
    • /
    • 2016
  • In this paper, we propose a new technique to the design and real-time control of an adaptive controller for robotic manipulator based on digital signal processors. The Texas Instruments DSPs(TMS320C80) chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved Lyapunov second method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for a dual arm robot manipulator with eight joints. joint space and cartesian space.

A Effective Method for Feature Detection and Enhancement in Fingerprint Images (지문의 특징 검출 및 향상을 위한 전처리 기법 연구)

  • Yang, Ryong;No, Jung-Seok;Lee, Sang-Bum
    • Journal of the Korea Computer Industry Society
    • /
    • v.3 no.12
    • /
    • pp.1775-1784
    • /
    • 2002
  • Fingerprint recognition technology is used in many biometrics field accordingly essential feature of fingerprint image and the study is progressing. However development is not perfect in performance of the fingerprint recognition and application of the usual life. In the paper, we study various necessity of preprocessing according to algorithm and circumstances of authentication system in automatic information machine. We prove that system circumstance and optation of fingerprints image effectively is the important factor by using optical fingerprint input device and scanning the fingerprint in ID card. And then we present correct and fast computation method for improving image and feature extraction of fingerprint. Also we study effective algorithm implementation of total system.

  • PDF

Face Feature Extraction for Face Recognition (얼굴 인식을 위한 얼굴 특징점 추출)

  • Yang, Ryong;Chae, Duk-Jae;Lee, Sang-Bum
    • Journal of the Korea Computer Industry Society
    • /
    • v.3 no.12
    • /
    • pp.1765-1774
    • /
    • 2002
  • A face recognition is currently the field which many research have been processed actively. But many problems must be solved the previous problem. First, We must recognize the face of the object taking a location various lighting change and change of the camera into account. In this paper, we proposed that new method to fund feature within fast and correct computation time after scanning PC camera and ID card picture. It converted RGB color space to YUV. A face skin color extracts which equalize a histogram of Y ingredient without the luminance. After, the method use V' ingredient which transformes V ingredient of YUV and then find the face feature. The reult of the experiment shows getting correct input face image from ID Card picture and PC camera.

  • PDF

Improving CMD Areal Density Analysis: Algorithms and Strategies

  • Wilson, R.E.
    • Journal of Astronomy and Space Sciences
    • /
    • v.31 no.2
    • /
    • pp.121-130
    • /
    • 2014
  • Essential ideas, successes, and difficulties of Areal Density Analysis (ADA) for color-magnitude diagrams (CMD's) of resolved stellar populations are examined, with explanation of various algorithms and strategies for optimal performance. A CMD-generation program computes theoretical datasets with simulated observational error and a solution program inverts the problem by the method of Differential Corrections (DC) so as to compute parameter values from observed magnitudes and colors, with standard error estimates and correlation coefficients. ADA promises not only impersonal results, but also significant saving of labor, especially where a given dataset is analyzed with several evolution models. Observational errors and multiple star systems, along with various single star characteristics and phenomena, are modeled directly via the Functional Statistics Algorithm (FSA). Unlike Monte Carlo, FSA is not dependent on a random number generator. Discussions include difficulties and overall requirements, such as need for fast evolutionary computation and realization of goals within machine memory limits. Degradation of results due to influence of pixelization on derivatives, Initial Mass Function (IMF) quantization, IMF steepness, low Areal Densities ($\mathcal{A}$), and large variation in $\mathcal{A}$ are reduced or eliminated through a variety of schemes that are explained sufficiently for general application. The Levenberg-Marquardt and MMS algorithms for improvement of solution convergence are contained within the DC program. An example of convergence, which typically is very good, is shown in tabular form. A number of theoretical and practical solution issues are discussed, as are prospects for further development.

Efficient Energy Detection Method in Poor Radio Environment for Cognitive Radio System (Cognitive Radio 시스템을 위한 열악한 통신 환경에서 효과적인 에너지 검출방법)

  • Hyun, Young-Ju;Kim, Kyung-Seok
    • The Journal of the Korea Contents Association
    • /
    • v.7 no.7
    • /
    • pp.60-67
    • /
    • 2007
  • The spectrum sensing is important for decision of using frequency band. It checks the frequency band for cognitive radio system. In this paper, we apply autocorrelation function to the energy detection method. We use the autocorrelation function to improve the performance of spectrum sensing method based on the energy detection method. This method is different from cyclostationary process method where parameters such as the mean or the autocorrelation function are time-varying periodically. And we propose improved method that is robust in poor radio environment. If the proposed method applies for sensing in the cognitive radio system, it will have the structural simplicity and the fast computation of spectrum sensing.