• Title/Summary/Keyword: Eigenvalue approach

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Milling Chatter Stability Analysis in Consideration of Gyroscopic Effect (자이로 스코프 효과를 고려한 밀링 채터 안정성 해석)

  • 박재현;홍성욱;김현수;박중윤
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.2
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    • pp.58-63
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    • 2000
  • The dynamics of spindle-bearing-workpiece system significantly affects the cutting condition and stability in milling process. The present paper investigates the chatter stability of milling process due to the change in the dynamics of spindle-bearing-workpiece systems. In particular, the present paper focuses on chatter stability due to the presence of gyroscopic effect. An eigenvalue problem approach to the stability of milling process is extensively used in this paper. To incorporate the rotational speed dependent gyroscopic effect, an iterative algorithm is proposed. A numerical example is provided for examining the chatter stability problem in the presence of gyroscopic effects.

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An Approach to Target Tracking Using Region-Based Similarity of the Image Segmented by Least-Eigenvalue (최소고유치로 분할된 영상의 영역기반 유사도를 이용한 목표추적)

  • Oh, Hong-Gyun;Sohn, Yong-Jun;Jang, Dong-Sik;Kim, Mun-Hwa
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.4
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    • pp.327-332
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    • 2002
  • The main problems of computational complexity in object tracking are definition of objects, segmentations and identifications in non-structured environments with erratic movements and collisions of objects. The object's information as a region that corresponds to objects without discriminating among objects are considered. This paper describes the algorithm that, automatically and efficiently, recognizes and keeps tracks of interest-regions selected by users in video or camera image sequences. The block-based feature matching method is used for the region tracking. This matching process considers only dominant feature points such as corners and curved-edges without requiring a pre-defined model of objects. Experimental results show that the proposed method provides above 96% precision for correct region matching and real-time process even when the objects undergo scaling and 3-dimen-sional movements In successive image sequences.

Point Values and Normalization of Two-Direction Multi-wavelets and their Derivatives

  • KEINERT, FRITZ;KWON, SOON-GEOL
    • Kyungpook Mathematical Journal
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    • v.55 no.4
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    • pp.1053-1067
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    • 2015
  • A two-direction multiscaling function ${\phi}$ satisfies a recursion relation that uses scaled and translated versions of both itself and its reverse. This offers a more general and flexible setting than standard one-direction wavelet theory. In this paper, we investigate how to find and normalize point values and derivative values of two-direction multiscaling and multiwavelet functions. Determination of point values is based on the eigenvalue approach. Normalization is based on normalizing conditions for the continuous moments of ${\phi}$. Examples for illustrating the general theory are given.

Power System Sensitivity Analysis for Probabilistic Small Signal Stability Assessment in a Deregulated Environment

  • Dong Zhao Yang;Pang Chee Khiang;Zhang Pei
    • International Journal of Control, Automation, and Systems
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    • v.3 no.spc2
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    • pp.355-362
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    • 2005
  • Deregulations and market practices in power industry have brought great challenges to the system planning area. In particular, they introduce a variety of uncertainties to system planning. New techniques are required to cope with such uncertainties. As a promising approach, probabilistic methods are attracting more and more attentions by system planners. In small signal stability analysis, generation control parameters play an important role in determining the stability margin. The objective of this paper is to investigate power system state matrix sensitivity characteristics with respect to system parameter uncertainties with analytical and numerical approaches and to identify those parameters have great impact on system eigenvalues, therefore, the system stability properties. Those identified parameter variations need to be investigated with priority. The results can be used to help Regional Transmission Organizations (RTOs) and Independent System Operators (ISOs) perform planning studies under the open access environment.

Diagnosis of chatter by using the chatter frequency-spindle speed diagram (채터 주파수-회전 속도 선도를 이용한 채터 진단에 관한 연구)

  • 이상호;이대형;박중윤;홍성욱
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.261-264
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    • 2000
  • This paper presents a method to identify the on-set of chatter by using the chatter frequency-spindle speed diagram for a milling spindle-workpiece system in face milling process. To this purpose, the eigenvalue problem approach using frequency response function is adopted for predicting both the chatter condition and chatter frequency. The chatter frequency -spindle speed diagram for various conditions is investigated throughout simulation and experiment to diagnose the chatter. The simulation and experimental results show that the chatter frequency-spindle speed diagram is useful for diagnosis of the on-set of chatter vibration.

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Application of the first-order perturbation method to optimal structural design

  • Lee, Byung Woo;Lim, O Kaung
    • Structural Engineering and Mechanics
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    • v.4 no.4
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    • pp.425-436
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    • 1996
  • An application of the perturbation method to optimum structural design with random parameters is presented. It is formulated on the basis of the first-order stochastic finite element perturbation method. It also takes into full account the stress, displacement and eigenvalue constraints, together with the rates of change of the random variables. A method for calculating the sensitivity coefficients in regard to the governing equation and the first-order perturbed equation has been derived, by using a direct differentiation approach. A gradient-based nonlinear programming technique is used to solve the problem. The numerical results are specifically noted, where the stiffness parameter and external load are treated as random variables.

Small signal stability analysis of power systems with non-continuous operating elements by using RCF method : Modeling of the state transition equation (불연속 동작특성을 갖는 전력계통의 RCF법을 사용한 미소신호 안정도 해석 : 상태천이 방정식으로의 모델링)

  • Kim Deok Young
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.342-344
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    • 2004
  • In conventional small signal stability analysis, system is assumed to be invariant and the state space equations are used to calculate the eigenvalues of state matrix. However, when a system contains switching elements such as FACTS devices, it becomes non-continuous system. In this case, a mathematically rigorous approach to system small signal stability analysis is by means of eigenvalue analysis of the system periodic transition matrix based on discrete system analysis method. In this research, RCF(Resistive Companion Form) method is used to analyse small signal stability of a non-continuous system including switching elements'. Applying the RCF method to the differential and integral equations of power system, generator, controllers and FACTS devices including switching elements should be modeled in the form of state transition matrix. From this state transition matrix eigenvalues which are mapped to unit circle can be calculated.

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Design of an Adaptive Nonlinear Compensator using a Wavelet Transform Domain Volterra Filter and a Modified Escalator Algorithm

  • Hwang, Dong-Oh;Kang, Dong-Jun;Nam, Sang-Won
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.98.5-98
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    • 2001
  • An efficient adaptive nonlinear compensator, based on a wavelet transform domain adaptive Volterra filter along with a modified escalator algorithm, is proposed to speed up the convergence rate of an adaptive LMS algorithm. In particular, it is well known that the e.g., slow convergence speed of an adaptive LMS algorithm depends on the statistical characteristics (e.g., large eigenvalue spread) of the corresponding auto-correlation matrix of the input vector. To solve such a convergence problem, the proposed approach utilizes a modified escalator algorithm and a wavelet transform domain adaptive LMS Volterra filtering technique, which leads to diagonalization of the auto-correlation matrix of the ...

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Structural Dynamic Optimization of Diesel Generator systems Using Genetic Algorithm(GA) (유전자 알고리즘을 이용한 선박용 디젤발전기 시스템의 동특성 해석 및 최적화)

  • 이영우;성활경
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.3
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    • pp.99-105
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    • 2000
  • For multi-body dynamic problems. especially coalescent eigenvalue problems with multiobjective optimization, the design sensitivity analysis is too much complicated mathematically and numerically. Therefore, this article proposes a new technique for structural dynamic modification using a mode modification and homologous structures design method with Genetic Algorithm(GA). In this work, the homologous structure of the resiliently mounted multi-body for marine diesel generator systems is studied and the problem is treated as a combinational optimization problem using the GA. In GA formulation, fitness is defined based on penalty function approach. That include homology, allowable stress and minimum weight of common plate.

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Mixed $\textrm{H}_2/\textrm{H}_infty$ Control with Pole Placement : A Convex Optimization Approach

  • Bambang, Riyanto;Shimemura, Etsujiro;Uchida, Kenko
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.197-202
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    • 1992
  • In this paper, we consider the synthesis of mixed H$_{2}$/H$_{\infty}$ controllers such that the closed-loop poles are located in a specified region in the complex plane. Using solution to a generalized Riccati equation and a change of variable technique, it is shown that this synthesis problem can be reduced to a convex optimization problem over a bounded subset of matrices. This convex programming can be further reduced to Generalized Eigenvalue Minimization Problem where Interior Point method has been recently developed to efficiently solve this problem..

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