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1.
This paper deals with the stabilization of semilinear parabolic distributed systems by means of boundary controls. The partial differential equation describing the system is formulated as a semilinear evolution equation in a Hilbert space by using a variable transformation. Here it is shown that the solution globally exists for the closed-loop system which installs a finite-dimensional dynamic compensator by using the properties of an analytic semigroup. Moreover, a sufficient condition for stabilization of the system is derived by making use of the modified Gronwall's inequality developed in this paper. 相似文献
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In the analysis of a recently proposed distributed estimation algorithm based on the Kalman filtering and on gossip iterations, we needed to apply a new inequality which is valid for i.i.d. matrix valued random processes. This inequality can be useful in the analysis of the convergence rate of general jump Markov linear systems.In this paper, we present this inequality. This is based on the theory of majorization and on its use in the analysis of the singular values. Finally we will show the impact of this inequality on the performance analysis of gossip based distributed Kalman filters. 相似文献
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为进一步提高保密通信的安全性,应用Lyapunov稳定性理论以及自适应控制方法,在广义混合错位投影同步与函数投影同步的基础上提出了广义混合错位函数投影同步(GHDFPS),给出了不同阶参数不确定混沌系统的广义混合错位函数投影同步与参数辨识的控制方法,并研究该同步类型在保密通信中的应用。通过严格的数学证明和数值仿真,不同阶参数不确定混沌系统实现了广义混合错位函数投影同步,辨识出了不确定参数。由于广义混合错位函数投影同步中的函数比例因子矩阵的多样性,使该同步类型应用在保密通信中更具有安全性;同时,将此同步类型和实现该同步的控制方法用于混沌掩饰调制保密通信中,将能解调出多个信号,并能检验信号的真实性。 相似文献
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分布式系统安全性和可靠性检测的难点在于缺乏对系统脆性的动态评估. 针对这一难点, 提出一种新的概念脆性相对熵来衡量系统的脆性, 并给出评估方法. 利用脆性相对熵可以动态地衡量当前概率分布与系统崩溃概率分布之间的相对距离, 有效地评估系统当前状态, 并对系统脆性的概率风险加以定量分析. 仿真结果表明, 脆性相对熵可以衡量系统的脆性特征, 且越接近系统脆性分布, 脆性相对熵越小. 相似文献
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可靠性优化问题是大型复杂系统设计的一个关键问题。针对大型复杂系统多个指标(可靠度、造价和冗余数)同时进行最优分配的结果多样性不好的问题,提出了一种基于杂草克隆的多目标粒子群算法—IWMOP-SO(invasive weed multi-objective particle swarm optimization)的多指标分配方法。该分配方法通过引入杂草克隆机制来改善Pareto最优解的收敛性和多样性。通过对大型复杂系统多个指标进行分配,其分配效果与NSGA-Ⅱ相比,得到的Pareto非劣解集多样性和均匀性好,分布范围更广,更利于设计者进行决策,是一种更有效的复杂系统多指标分配方法。 相似文献
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Generalized symmetry and its application to 3D shape generation 总被引:1,自引:0,他引:1
A new method for easily and rapidly generating three-dimensional shapes from two-dimensional line-drawings is presented. This method is based on the generalized symmetry constraint. Generalized symmetry is an extended concept of threedimensional symmetry and its axis is a 3D smooth curve. This paper first develops the definition and constraint of generalized symmetry, and then describes an algorithm which generates the three-dimensional shape of an object from its linedrawing. The generation algorithm is extended to generate generalized cylindrical objects from line-drawings. Several experiments by computer simulation verify that the algorithm can generate three-dimensional shapes from line-drawings. 相似文献
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《Computers & Mathematics with Applications》2007,53(1):104-114
This paper deals with the generalization and sharp versions of the Wolstenholme cyclic inequality and their applications. The inequalities of this paper improve and unify corresponding known results. Several interesting inequalities including the celebrated Ozeki inequality are obtained. Extensions of the Wolstenholme inequality for a complex polygon and the Wolstenholme inequality for a convex quadrilateral are derived. As example of applications, the well-known Erdös–Mordell inequality is improved in this paper. In addition, several extensions, unifications and refinements of Gueron–Shafrir’s inequalities and Mitrinović–Pecaric’s inequality are established. 相似文献
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S.G. Tzafestas 《Mathematics and computers in simulation》1983,25(3):214-225
The purpose of this paper is to provide an overview of the works dealing with the application and utilization of Walsh function series and transforms to a variety of systems and control applications. The works reviewed are classified in the following groups: 1. Walsh signal definition and generation, 2. Walsh transform Computation, 3. System analysis using Walsh functions, 4. System identification via Walsh functions, 5. Optimal control via Walsh functions, 6. Block-pulse functions, 7. Miscellaneous properties of Walsh functions, 8. Walsh-to-Fourier transform conversion, and 9. Walsh transform applications. 相似文献
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Li He Guo-He Huang Guang-Ming Zeng Hong-Wei Lu 《Expert systems with applications》2008,35(3):1301-1310
Data cleaning techniques are useful for extracting desirable knowledge or interesting patterns from existing databases in engineering applications. The major problems of conventional techniques (e.g., Fourier Transformation Technique) are that they are (1) more appropriate in linear systems than nonlinear systems, and (2) stringently depend on state space functions. In this study a wavelet-based multiresolution analysis technique (WMAT) is proposed for reducing noises induced by complex uncertainty. The approach is applied to a river water quality simulation system for showing its practicability in data cleaning and parameter estimation. Clean data are prepared through running a Thomas’ river water quality model and polluted data are synthesized by mixing clean data with white Gaussian noises. The results show that WMAT will not distort the clean data, and can effectively reduce the noise in the polluted data. The data denoised by WMAT are furthermore used for estimating the modeling parameters. It is also indicated that the parameters estimated with the denoised data through WMAT are much closer to real values than those (1) with polluted data through WMAT and (2) with data through Fourier analysis technique. It is thus recommended that the prepared data be used for estimating the modeling parameters until being cleaned with WMAT. 相似文献
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Absolute instability of Lur'e systems and its application to oscillation analysis of uncertain genetic networks 下载免费PDF全文
Masaki Inoue Jun‐ichi Imura Kenji Kashima Masayasu Suzuki Kazuyuki Aihara 《国际强度与非线性控制杂志
》2015,25(18):3746-3762
》2015,25(18):3746-3762
We derive instability criteria for Lur'e systems with sector‐bounded nonlinearities and uncertain external signals. First, we define absolute instability of an equilibrium and derive an absolute instability condition for a fixed equilibrium point in terms of a linear matrix inequality, which is analogous to the well‐known circle stability criterion. Then, the condition is extended to a parametric absolute instability condition, which is applicable to the instability test of a Lur'e system with an equilibrium point whose location is affected by uncertain nonlinearities and uncertain external signals. Finally, we show that the proposed analysis method is useful through the oscillation analysis of an uncertain genetic network model. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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One of the main obstacles facing current intelligent pattern recognition applications is that of dataset dimensionality. To enable these systems to be effective, a redundancy-removing step is usually carried out beforehand. Rough set theory (RST) has been used as such a dataset pre-processor with much success, however it is reliant upon a crisp dataset; important information may be lost as a result of quantisation of the underlying numerical features. This paper proposes a feature selection technique that employs a hybrid variant of rough sets, fuzzy-rough sets, to avoid this information loss. The current work retains dataset semantics, allowing for the creation of clear, readable fuzzy models. Experimental results, of applying the present work to complex systems monitoring, show that fuzzy-rough selection is more powerful than conventional entropy-, PCA- and random-based methods. 相似文献
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This paper considers a stability analysis issue of piecewise non-linear systems and applies it to intermittent synchronisation of chaotic systems. First, based on piecewise Lyapunov function methods, more general and less conservative stability criteria of piecewise non-linear systems in periodic and aperiodic cases are presented, respectively. Next, intermittent synchronisation conditions of chaotic systems are derived which extend existing results. Finally, Chua's circuit is taken as an example to verify the validity of our methods. 相似文献
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A new method for optimizing complex engineering designs is presented that is based on the Learnable Evolution Model (LEM), a recently developed form of non‐Darwinian evolutionary computation. Unlike conventional Darwinian‐type methods that execute an unguided evolutionary process, the proposed method, called LEMd, guides the evolutionary design process using a combination of two methods, one involving computational intelligence and the other involving encoded expert knowledge. Specifically, LEMd integrates two modes of operation, Learning Mode and Probing Mode. Learning Mode applies a machine learning program to create new designs through hypothesis generation and instantiation, whereas Probing Mode creates them by applying expert‐suggested design modification operators tailored to the specific design problem. The LEMd method has been used to implement two initial systems, ISHED1 and ISCOD1, specialized for the optimization of evaporators and condensers in cooling systems, respectively. The designs produced by these systems matched or exceeded in performance the best designs developed by human experts. These promising results and the generality of the presented method suggest that LEMd offers a powerful new tool for optimizing complex engineering systems. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1217–1248, 2006. 相似文献
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《Advances in Engineering Software》2006,37(9):624-629
This paper provided the stability conditions and controller design for a class of structural and mechanical systems represented by Takagi–Sugeno (T–S) fuzzy models. In the design procedure of controller, parallel-distributed compensation (PDC) scheme was utilized to construct a global fuzzy logic controller by blending all local state feedback controllers. A stability analysis was carried out not only for the fuzzy model but also for a real mechanical system. Furthermore, this control problem can be reduced to linear matrix inequalities (LMI) problems by the Schur complements and efficient interior-point algorithms are now available in Matlab toolbox to solve this problem. A simulation example was given to show the feasibility of the proposed fuzzy controller design method. 相似文献
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A finite quasi-prismatic (FQP) element is modified to analyze anisotropic materials. The finite quasi-prismatic element is a three-dimensional finite element which uses conventional interpolating functions in two directions and functions based on Chebyshev polynomials in the third direction. This element is used to solve different anisotropic problems and the results are compared with that of conventional finite elements and analytical solutions. 相似文献
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最小二乘支持向量机(LS SVM)是处理不可分样本集情况下模式分类的有效工具,但是该算法在处理很多实际分类问题时,表现出了一定的局限性。为了进一步增强最小二乘支持向量机的推广能力,提出一种通用的广义最小二乘支持向量机算法,并且把这种新算法首先应用到雷达一维距离像的识别中,实验表明新的算法能取得更好的识别效果。 相似文献
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A new integral inequality and its applications to robust control problems of uncertain nonlinear systems 下载免费PDF全文
Hansheng Wu 《国际强度与非线性控制杂志
》2018,28(15):4584-4603
》2018,28(15):4584-4603
In this paper, a new integral inequality is presented. By combining this integral inequality with adaptive approach, new design methods can be developed to synthesize some adaptive robust control schemes for a large class of uncertain nonlinear systems and to deal with well the unknown nonlinearities appearing in uncertain nonlinear control dynamical systems. As an application of the presented integral inequality to control theory, the robust stabilization problem is considered for a class of uncertain strict‐feedback nonlinear systems with both time‐delay and unknown dead‐zone input nonlinearities. It is shown that there are two main merits in the design method based on the integral inequality presented in this paper. The first one is that one need not estimate and know the unknown nonlinearities to synthesize some stabilizing control schemes. The second one is that the resulting feedback control schemes have rather simple structure. 相似文献
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The notion of partial eigenstructure assignment (PEA) via linear state feedback control in linear multivariable systems is introduced. This notion is a natural extension of eigenstructure assignment and partial eigenvalue assignment. Some theoretical basis for PEA is provided, and a parametric expression for feedback gain matrices achieving PEA is derived. An effective numerical algorithm for PEA tailored to large-scale systems is presented. As an extension of the algorithm, a recursive algorithm for eigenstructure assignment is presented. These algorithms possess the following desired properties: (1) compared to existing methods, the presented algorithms significantly reduce the required computation time via transforming high-dimensional matrix computations into low-dimensional matrix computations; (2) they can be implemented in a parallel fashion. The proposed algorithm for PEA is applied to modal control of large flexible space structure systems 相似文献