• Title/Summary/Keyword: Non-linear systems

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A NEW APPROACH FOR NUMERICAL SOLUTION OF LINEAR AND NON-LINEAR SYSTEMS

  • ZEYBEK, HALIL;DOLAPCI, IHSAN TIMUCIN
    • Journal of applied mathematics & informatics
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    • v.35 no.1_2
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    • pp.165-180
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    • 2017
  • In this study, Taylor matrix algorithm is designed for the approximate solution of linear and non-linear differential equation systems. The algorithm is essentially based on the expansion of the functions in differential equation systems to Taylor series and substituting the matrix forms of these expansions into the given equation systems. Using the Mathematica program, the matrix equations are solved and the unknown Taylor coefficients are found approximately. The presented numerical approach is discussed on samples from various linear and non-linear differential equation systems as well as stiff systems. The computational data are then compared with those of some earlier numerical or exact results. As a result, this comparison demonstrates that the proposed method is accurate and reliable.

Non-linear Finite Element Analysis and Performance Evaluations of Frames Strengthened by Non-uniform Concrete Brace Facade (비정형 콘크리트 가새 파사드 보강 골조의 비선형 유한요소 해석 및 성능평가)

  • Lee, Sun-Ju;Kim, Hyo-Ju;Cho, Chang-Geun
    • Journal of Korean Association for Spatial Structures
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    • v.24 no.1
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    • pp.73-80
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    • 2024
  • Non-uniform reinforced concrete brace facade systems are newly considered to improve seismic performance of reinforced concrete frame buildings under lateral load. For normal and high strength concrete of 30MPa, 80MPa, and 120MPa, the cross-sections of reinforced concrete brace facade systems were designed as different size with same amount of reinforcements. The strengthened frame systems were analyzed by a non-linear two-dimensional finite element technique which was considering material non-linearities of concrete and reinforcing bars under monotonic and cyclic loadings. From the study of non-linear analysis of the systems, therefore, it was provided that the proposed braced facade systems were reliable to improve laterally load-carrying capacity and minimize damages of concrete members through comparisons of load-displacement curves, crack patterns, and stress distributions of reinforcing bars predicted by current non-linear finite element analysis of frame specimens.

The Control of Flexible Beam using Nonlinear Compensator with Dual-Input Describing Function (쌍입력 기술함수를 갖는 비선형 보상기를 이용한 유연한 빔의 제어)

  • 권세현;이형기;최부귀
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.5
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    • pp.644-650
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    • 1998
  • In this paper , a state space model for flexible beam is presented using the assumed-modes approach. The state space equation is derived for a flexible beam in which one end is connected to a motor and is driven by a torque equation and the other end is free. Many of the transfer function proposed thus far use the torque to the flexible beam as the input and the tip deflection of the flexible beam as the output. The Technique for the analysis and synthesis of the dual-input describing function(DIDF) is introduced here and the construction of a non-linear compensator, based on this technique, is proposed. This non-linear compensator, properly connected in the direct path of a closed-loop linear or non-linear control system. The above non-linear network is used to compensate linear and non-linear systems for instability, limit cycles, low speed of response and static accuracy. The effectiveness of the proposed scheme is demonstrated through computer simulation and experimental results.

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DS-PAM UWB System Using Non-linear Chirp Waveform

  • Shen, Hanbing;Zhang, Weihua;An, Xizhi;Kwak, Kyung-Sup
    • ETRI Journal
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    • v.29 no.3
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    • pp.322-328
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    • 2007
  • We propose a direct-sequence pulse-amplitude modulation (DS-PAM) ultra-wideband (UWB) system which employs a non-linear chirp waveform instead of the conventional Gaussian monocycle in this paper. In the approved frequency for UWB, there exist myriad narrowband interferers. Specifically, we focus on the mutual interference between UWB systems and 802.11a WLAN. This paper offers a method to suppress this in-band narrowband interference by introducing a kind of non-linear chirp waveform. Using the proposed non-linear chirp waveform, the effects of one or more narrowband interference sources with different frequencies can be suppressed. System performance of UWB systems in the narrowband interference environment can be improved. Computer simulations with additive white Gaussian noise successfully demonstrate an increase in performance with the proposed system as compared to traditional linear chirp systems.

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Neuro-Fuzzy Identification for Non-linear System and Its Application to Fault Diagnosis (비선형 계통의 뉴로-퍼지 동정과 이의 고장 진단 시스템에의 적용)

  • 김정수;송명현;이기상;김성호
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.10a
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    • pp.447-452
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    • 1998
  • A fault is considered as a variation of physical parameters; therefore the design of fault detection and identification(FDI) can be reduced to the parameter identification of a non linear system and to the association of the set of the estimated parameters with the mode of faults. ANFIS(Adaptive Neuro-Fuzzy Inference System) which contains multiple linear models as consequent part is used to model non linear systems. In this paper, we proposes an FDI system for non linear systems using ANFIS. The proposed diagnositc system consists of two ANFISs which operate in two different modes (parallel-and series-parallel mode). It generates the parameter residuals associated with each modes of faults which can be further processed by additional RBF (Radial Basis function) network to identify the faults. The proposed FDI scheme has been tested by simultation on a two-tank system

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Collapse behaviour of three-dimensional brick-block systems using non-linear programming

  • Baggio, Carlo;Trovalusci, Patrizia
    • Structural Engineering and Mechanics
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    • v.10 no.2
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    • pp.181-195
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    • 2000
  • A two-step procedure for the application of non linear constrained programming to the limit analysis of rigid brick-block systems with no-tension and frictional interface is implemented and applied to various masonry structures. In the first step, a linear problem of programming, obtained by applying the upper bound theorem of limit analysis to systems of blocks interacting through no-tension and dilatant interfaces, is solved. The solution of this linear program is then employed as initial guess for a non linear and non convex problem of programming, obtained applying both the 'mechanism' and the 'equilibrium' approaches to the same block system with no-tension and frictional interfaces. The optimiser used is based on the sequential quadratic programming. The gradients of the constraints required are provided directly in symbolic form. In this way the program easily converges to the optimal solution even for systems with many degrees of freedom. Various numerical analyses showed that the procedure allows a reliable investigation of the ultimate behaviour of jointed structures, such as stone masonry structures, under statical load conditions.

The Direction of Improvement Non-linear Editing Software (비선형 편집 소프트웨어의 개선방향)

  • Park, Sung-Dae
    • Journal of Korea Multimedia Society
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    • v.16 no.8
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    • pp.972-981
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    • 2013
  • Non-linear editing is an editing method that, unlike linear editing, enables users to insert a new frame between existing frames. Non-linear editing systems are systems that support such method, and are composed of a computer, a software and a capture board that inputs/outputs video signals. Non-linear editing is used for modern television broadcasts and movie productions. Recorded footage and various graphic sources are combined into one visual content through a non-linear editing system. In this paper, we will look into functions of various non-linear editing softwares (mainly the most common of all; Adobe Premiere) as well as their merits and demerits during the editing process, and will also discuss their future Improvement direction.

Non-linear PLS based on non-linear principal component analysis and neural network (비선형 주성분해석과 신경망에 기반한 비선형 PLS)

  • 손정현;정신호;송상옥;윤인섭
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.394-394
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    • 2000
  • This Paper proposes a new nonlinear partial least square method that extends the linear PLS. Proposed nonlinear PLS uses self-organizing feature map as PLS outer relation and multilayer neural network as PLS inner regression method.

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Efficient non-linear analysis and optimal design of biomechanical systems

  • Shojaei, I.;Kaveh, A.;Rahami, H.;Bazrgari, B.
    • Biomaterials and Biomechanics in Bioengineering
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    • v.2 no.4
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    • pp.207-223
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    • 2015
  • In this paper a method for simultaneous swift non-linear analysis and optimal design/posture of mechanical/biomechanical systems is presented. The method is developed to get advantages of iterations in non-linear analysis and/or generations in genetic algorithm (GA) for the purpose of efficient analysis within the optimal design/posture. The method is applicable for both size and geometry optimizations wherein material and geometry non-linearity are present. In addition to established mechanical systems, the method can solve biomechanical models of human musculoskeletal system. Optimization-based procedures are popular methods for resolving the redundancy at joints wherein the number of unknown muscle forces is far more than the number of equilibrium equations. These procedures involve optimization of a cost function(s) which is assumed to be consistent with the central nervous system's strategy when activating muscles to assure equilibrium. However, because of the complexity of biomechanical problems (i.e., due to non-linear biomaterial, large deformation, redundancy of the problem and so on) efficient analysis are required within optimization procedures as suggested in this paper.

Design of A Robust Adaptive Controller for A Class of Uncertain Non-linear Systesms with Time-delay Input

  • Nguyen, Thi-Hong-Thanh;Cu, Xuan-Thinh;Nguyen, Thi-Minh-Huong;Ha, Thi-Hoan;Nguyen, Dac-Hai;Tran, Van-Truong
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1955-1959
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    • 2005
  • This paper presents a systematic analysis and a simple design of a robust adaptive control law for a class of non linear systems with modeling errors and a time-delay input. The theory for designing a robust adaptive control law based on input- output feedback linearization of non linear systems with uncertainties and a time-delay in the manipulated input by the approach of parameterized state feedback control is presented. The main advantage of this method is that the parameterized state feedback control law can effectively suppress the effect of the most parts of nonlinearities, including system uncertainties and time-delay input in the pp-coupling perturbation form and the relative order of non linear systems is not limited.

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