• Title/Summary/Keyword: exact approach

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Model-free $H_{\infty}$ Control of Linear Discrete-time Systems using Q-learning and LMI Based on I/O Data (입출력 데이터 기반 Q-학습과 LMI를 이용한 선형 이산 시간 시스템의 모델-프리 $H_{\infty}$ 제어기 설계)

  • Kim, Jin-Hoon;Lewis, F.L.
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.7
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    • pp.1411-1417
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    • 2009
  • In this paper, we consider the design of $H_{\infty}$ control of linear discrete-time systems having no mathematical model. The basic approach is to use Q-learning which is a reinforcement learning method based on actor-critic structure. The model-free control design is to use not the mathematical model of the system but the informations on states and inputs. As a result, the derived iterative algorithm is expressed as linear matrix inequalities(LMI) of measured data from system states and inputs. It is shown that, for a sufficiently rich enough disturbance, this algorithm converges to the standard $H_{\infty}$ control solution obtained using the exact system model. A simple numerical example is given to show the usefulness of our result on practical application.

A PROPAGATION ALGORITHM FOR INTERVAL-BASED CONDITIONAL CONSTRAINTS (Interval을 이용한 Conditional Constraints의 Propagation 알고리듬)

  • Kim, Kyeong-Taek
    • Journal of Korean Institute of Industrial Engineers
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    • v.20 no.1
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    • pp.133-146
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    • 1994
  • Conditional constraints are frequently used to represent relations. To use these conditional constraints, it is necessary to develop an appropriate logic in which these conditional constraints can be represented and manipulated. Nevertheless, there has been little research that addresses interval-based conditional constraints. The proposed approach addresses the use of conditional constraints involving intervals in constraint networks. Two algorithms are presented: (1) a propagation algorithm for an interval-based conditional constraint, which is similar to one for an exact-value conditional constraint; (2) a propagation algorithm for interval-based conditional constraints which satisfy some conditions. The former can be applied to any conditional constraint. However, with the former algorithm, conditional constraints are usually categorized into the cases that they cannot be propagated. After investigating several methods in which most conditional constraints can be propagated, we propose the latter algorithm under certain condition that usually results in smaller resulting design space comparing to the former.

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Finding approximate occurrence of a pattern that contains gaps by the bit-vector approach

  • Lee, In-Bok;Park, Kun-Soo
    • Proceedings of the Korean Society for Bioinformatics Conference
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    • 2003.10a
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    • pp.193-199
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    • 2003
  • The application of finding occurrences of a pattern that contains gaps includes information retrieval, data mining, and computational biology. As the biological sequences may contain errors, it is important to find not only the exact occurrences of a pattern but also approximate ones. In this paper we present an O(mnk$_{max}$/w) time algorithm for the approximate gapped pattern matching problem, where m is the length of the text, H is the length of the pattern, w is the word size of the target machine, and k$_{max}$ is the greatest error bound for subpatterns.

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Loss Optimization for Voltage Stability Enhancement Incorporating UPFC Using Particle Swarm Optimization

  • Kowsalya, M.;Ray, K.K.;Kothari, D.P.
    • Journal of Electrical Engineering and Technology
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    • v.4 no.4
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    • pp.492-498
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    • 2009
  • The placement of the UPFC is the major concern to ensure the full potential of utilization in the transmission network. Voltage stability enhancement with the optimal placement of UPFC using stability index such as modal analysis, Voltage Phasor method is made and the loss minimization including UPFC is formulated as an optimization problem. This paper proposes particle swarm optimization for the exact real power loss minimization including UPFC. The implementation of loss minimization for the optimal location of UPFC was tested with IEEE-14 and IEEE-57 bus system.

Robust Nonlinear Control of Air-to-Fuel Ratio in Spark Ignition Engines

  • Myoungho Sunwoo;Paljoo Yoon;Park, Seungbum;Lee, Wootaik
    • Journal of Mechanical Science and Technology
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    • v.15 no.6
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    • pp.699-708
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    • 2001
  • This paper presents a new approach to the AFR (Air-to-Fuel Ratio) control problem, which is based on the wide-band oxygen sensor output. The dedicated nonlinear controller is based on the feedback lineaization technique. It is well known that the feedback linearizing control technique requires an exact model of the plant for the cancellation of plant nonlinearities. A sliding mode control scheme is applied which can effectively compensate the modeling uncertainties. The measurement time delay of an oxygen sensor limits the gain of the feedback controller. Hence, time delay compensation procedure is necessary for the improvement of control performance. The Smith predictor is adopted to compensate the effects of time delay. The simulation and experimental results show that the proposed controllers can effectively reduce the transient peaks of AFR in spite of fast tip-in and tip-out maneuvers of the throttle.

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Case-Based Reasoning Using Self-Organization Map Neural Network (자기조직화지도 신경망을 이용한 사례기반추론)

  • Kim, Yong-Su;Yang, Bo-Suk;Kim, Dong-Jo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.832-835
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    • 2002
  • This paper presents a new approach integrated Case-Based Reasoning with Self. Organization Map(SOM) in diagnosis systems. The causes of faults are obtained by case-base trained from SOM. When the vibration problem of rotating machinery occurs, this provides an exact diagnosis method that shows the fault cause of vibration problem. In order to verify the performance of algorithm, we applied it to diagnose the fault cause of the electric motor.

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A Comparative Study on Methods of Jury Test used for Sound Preferences (소리 선호도 조사에 사용하는 청음평가법의 비교 연구)

  • Jo, Hyeonho;Seong, Wonchan;Kim, Seonghyeon;Park, Dongchul;Kang, Yeonjune
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.04a
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    • pp.165-170
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    • 2014
  • Quantifying the perception of human is of great interest for the optimal characterization of the interaction of persons with their environment. The direct approach to such measurements is based on jury-test methods. In this study we considered which jury-test method is more efficient and exact way to measure the preferences for operating sound of car. Moreover we needed to research selection criteria of jury-test methods in accordance with the properties of sound samples. We choose two sample sounds; door locks which generate simple impact sounds and window lifts which are consisted of long and complex sound. For each sound sample we conducted two jury-test methods respectively and discussed about the results.

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An Exact Algorithm for the Asymmetrical Vehicle Routing Problem (차량경로문제에 대한 최적해법)

  • 송성헌;박순달
    • Journal of the Korean Operations Research and Management Science Society
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    • v.12 no.1
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    • pp.34-44
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    • 1987
  • The general vehicle routing problem has been studied by many researchers such as Christofides, et al. and Laporte, et al., but only limited effort has been devoted to developing the optimal algorithms. The purpose of this paper is to develop a branch and bound algorithm which determines the optimal vechicle routes and the optimal number of vehicles concurrenetly for the asymmetrical vehicle routing problem. In order to enhance the efficiency, this algorithm emphasizes the followings ; First, an efficient primal-dual approach is developed to solve subproblems which are called the specialized transportation problem, formed by relaxing the illegal subtour constraints from the vehicle routing problem, second, an improved branching scheme is developed to reduce the number of candidate subproblems by adequate utilization of vehicle capacity restrictions.

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Sensorless Self-Tuning Adaptive Control of Nonlinear Modeled DC Motors Using DSP (DSP를 이용한 비선형 모델을 갖는 직류 전동기의 센서없는 자기동조 적응제어)

  • 김윤호;국윤상;유연식
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.9 no.6
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    • pp.49-56
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    • 1995
  • In this study, self-tuning adaptive control using state observer is developed. Self-tuning adaptive controller that estimates the parameters of the system in real time and generates the optimal control signals has robust characteristic about varying load and external disturbances. In addition, state observer without sensors is applied, thus the control can be performed more quickly and exactly. Since chopper is used commonly in practical drives, the characteristics of the chopper are included in state observer algorithm, which, in turn, makes the system exact estimation. Since series type DC motor has nonlinear models, linearizing approach are investigated. to realize the proposed algorithm it requires fast calculation in real time. TMS320C31, digital signal processor, is applied to realized the adaptive control algorithms.

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SOLVING MATRIX POLYNOMIALS BY NEWTON'S METHOD WITH EXACT LINE SEARCHES

  • Seo, Jong-Hyeon;Kim, Hyun-Min
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.12 no.2
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    • pp.55-68
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    • 2008
  • One of well known and much studied nonlinear matrix equations is the matrix polynomial which has the form $P(X)=A_0X^m+A_1X^{m-1}+{\cdots}+A_m$, where $A_0$, $A_1$, ${\cdots}$, $A_m$ and X are $n{\times}n$ complex matrices. Newton's method was introduced a useful tool for solving the equation P(X)=0. Here, we suggest an improved approach to solve each Newton step and consider how to incorporate line searches into Newton's method for solving the matrix polynomial. Finally, we give some numerical experiment to show that line searches reduce the number of iterations for convergence.

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