共查询到20条相似文献，搜索用时 406 毫秒
1.
Jui-Pin Tseng 《Journal of The Franklin Institute》2018,355(14):6549-6578
This investigation establishes the global synchronization of an array of coupled memristor-based neural networks with delays. The coupled networks that are considered can incorporate both the internal delay in each individual network and the transmission delay across different networks. The coupling scheme, which consists of a nonlinear term and a sign term, is rather general. In particular, it can be asymmetric, and admits the coexistence of excitatory and inhibitory connections. Based on an iterative approach, the problem of synchronization is transformed into solving a corresponding linear system of algebraic equations. Subsequently, the respective synchronization criteria, which depend on whether the transmission delay exists, are derived respectively. Three examples are given to illustrate the effectiveness of the theories presented in this paper. The synchronization of the systems in two examples cannot be handled by existing techniques. 相似文献
2.
L.O. Chua 《Journal of The Franklin Institute》1973,296(2):91-113
This paper presents a novel graph theoretic approach for deriving various stationary principles for single-element type nonlinear networks. The concepts of total content, co-content and hybrid content are generalized to that of total parametric content for resistive nonlinear networks containing multivalued elements. The results by Brayton and Moser on potential functions for complete m-ports are generalized to non-complete m-ports in terms of three pseudopotential functions; namely, the pseudo-content, pseudo- co-content and the pseudo-hybrid content. The precise criterion for which each of these pseudo-potential functions reduces to a legitimate potential function is shown to be the unique solvability of an implicit set of equations given explicitly in terms of standard topological matrices. Simple circuit theoretic sufficient conditions are given which require merely the positive-definiteness of the incremental resistance matrix of an auxiliary complete current-controlled p-port and the incremental conductance matrix of an auxiliary complete voltage-controlled q-port. These conditions also guarantee that a non-complete dynamic nonlinear network can be represented by a system of normal form differential equations in terms of a single mixed potential function. 相似文献
3.
In this paper, the state estimation problem is studied for a class of discrete-time stochastic complex networks with switched topology. In the network under consideration, we assume that measurement outputs can be got from only partial nodes, besides, the switching rule of this network is characterized by a sequence of Bernoulli random variables. The aim of the presented estimation problem is to develop a recursive estimator based on the framework of extended Kalman filter (EKF), such that the upper bound for the filtering error convariance is optimized. In order to address the nonlinear functions, the Taylor series expansion is utilized and the high-order terms of linearization errors are expressed in an exact way. Furthermore, by solving two Ricatti-like difference equations, the gain matrix can be acquired at each time instant. It is shown that the filtering error is bounded in mean square under some conditions with the aid of stochastic analysis techniques. A numerical example is given to demonstrate the validity of the proposed estimator. 相似文献
4.
Various aspects of analysis and synthesis of resistive n-port networks are considered in this paper. Two different characterizations of the network are examined, the Y matrix characterization and the K matrix characterization. Based on these characterizations, a set of equations is derived which relate the edge admittances with the elements of these matrices. When the K matrix is given, these equations are linear and can be solved analytically. When the Y matrix is given, the equations are bilinear and cannot be solved analytically. In this case, the problem is formulated as an optimization problem and techniques of nonlinear programming are used to obtain a realization. Synthesis from the Y matrix is finally extended to include sensitivity considerations. 相似文献
5.
T.N. Lee 《Journal of The Franklin Institute》1978,306(6):409-424
Studies of two-element-kind ladder networks are well known in the classical literature, among them, the most celebrated ones are due to Cauer. Driving point immittance function synthesis by using continued fractions to obtain the series and shunt arm L-C element values is a standard and routine work. The idea of introducing a class of more general networks, the inhomogeneous ladder networks, was first developed by Lee and Brown, and subsequently the synthesis techniques of such a network were established.In this paper, new results are found such as: (1) the Iff. conditions of the existence of an inhomogeneous ladder network by a given chain matrix of the network satisfying: (a) determinant of the chain matrix is 1; (b) the zeros of A(s) and z?1B(s) or A(s) and y?1C(s) alternate with respect to [z(s)y(s), k] with an appropriate leading set of zeros of A(s); (c) the poles of A(s) and z?1B(s) or A(s) and y?1C(s) are the poles of z(s)y(s) of multiplicity of n and n?1, where n the number of sections of ladder networks; (2) the Iff. condition for the inhomogeneous ladder network to be optimal is that it be antimetrical, whereas for the extended class of inhomogeneous ladder networks it is symmetrical, where an optimal inhomogeneous ladder network is defined as the corresponding network with the minimum sum of immittance levels in the series and shunt arms; (3) algorithms of synthesis procedures were developed as the by-products of the Theorems. 相似文献
6.
This paper aims to show that alliance networks can play an important role in facilitating large-scale strategic change projects. It focuses on the particular case of IBM, whose radical redirection from an exploitation strategy towards an exploration strategy was realized by major changes in its network strategy. We show that by involving new partners in the network and by loosening the ties with its existing partners, IBM managed to transform from a hardware manufacturing company to a global service provider and software company. The findings suggest that the traditional view of large firms as being slow to adapt may not be valid because alliance networks can be used to overcome inertia. 相似文献
7.
F.F. Shoji 《Journal of The Franklin Institute》1982,313(5):267-271
This brief communication establishes a two-step iterative algorithm based on the orthogonal projection for reducing order of the high-order system transfer function or state variable equations. A two-step iterative algorithm which has been developed by the authors (1) consists of the residue and pole (or eigenvalue) optimization with respect to the objective function. Here, the optimum residues in the first step can be determined by using the reciprocal basis in the projection theorem. The reciprocal basis allows one to avoid performing the Grammian inversion. Selecting the new basis, the optimum poles in the second step can be also applied for the orthogonal projection. Although the resulting reduced-order models derived from this geometrical point of view are consistent with models of a two-step iterative algorithm, the algorithm is thus a computationally much simpler way to derive the formula. 相似文献
8.
《Journal of The Franklin Institute》2023,360(12):8178-8199
In large-scale complex dynamical networks, it is significant to estimate the states of target nodes with only a part of measured nodes. Meanwhile, multilayer complex dynamical networks exist widely in society and engineering. Therefore, it has important theoretic meaning and practical value to study the state estimation of target nodes in multilayer complex dynamical networks with limited node measurements. In this paper, with the measurable state information of a portion of nodes in one layer in the multilayer complex dynamical network, the state estimation of target nodes in other layers is studied. First, we build the model of the multilayer complex dynamical network which includes some target nodes and sensor nodes. Second, auxiliary nodes are selected by using the maximum matching principle in graph theory to construct the augmented node set. Third, we discuss the relationship between the minimum number of auxiliary nodes and interlayer connection probability in the multilayer complex dynamical network. Forth, an appropriate functional state observer is designed with limited number of measured nodes according to a typical model-based algorithm. Finally, numerical simulations are given to demonstrate the accuracy of the proposed method. The proposed method can achieve the accurate estimation with less placement of observers and fewer computational costs in the multilayer complex dynamical network. 相似文献
9.
《Journal of The Franklin Institute》2022,359(11):5575-5595
This paper is devoted to solving the recursive state estimation (RSE) issue for a class of complex networks (CNs) with Round-Robin (RR) protocol and switching nonlinearities (SNs). A random variable obeying the Bernoulli distribution with known statistical properties is introduced to describe the switching phenomenon between two nonlinear functions. A Gaussian noise and time-varying outer coupling strength are adopted to show the changeable network topology (CNT). The RR protocol is applied to regulate signal transmissions, which determines that the element in measurement output has access to the communication networks at each step. The purpose of this paper is to construct a recursive state estimator such that, for all SNs, time-varying topology and RR protocol, the expected state estimation performance is guaranteed. Specifically, based on two recursive matrix equations, the covariance upper bound (CUB) of state estimation error is obtained firstly and then minimized via designing estimator gain in a proper way. Moreover, a feasible criterion is given to guarantee that the trace of obtained CUB is bounded and a monotonicity relationship is established between state estimation error and time-varying outer coupling strength. Lastly, a simulation experiment is illustrated to verify the feasibility of the addressed estimation method. 相似文献
10.
A unified variational approach to network analysis is presented. From an initial classification of variables, expressed in topological terms, Lagrangian energy functions are generated which may be used in Hamilton's principles. This topological formalism allows extension into nonconservative networks and enables the complete retention of classical formalism in all networks.By using a topological version of the Brayton-Moser mixed potential function, several power variational principles are developed. These principles lead to comparison of the roles played by classical energy and power state functions in analytical mechanics. 相似文献
11.
Numerical integration is the most common and straightforward approach in computational neuroscience for the study of biological neuron models based on ordinary differential equations. For some purposes, numerical simulations are not enough due to the multiple bottlenecks in computer architectures. However, when electronic circuits are used to simulate in real time large arrays of coupled neurons, the simulations are much faster than the computer simulations. We present here an electronic implementation of a map-based neuron model, a chaotic Rulkov neuron model, that can be easily transferred on a large scale integration circuit and thus provide a framework for the simulation of large networks of neurons. The Rulkov model is a map-based neuron model that has a surprising abundance of features, such as periodic and chaotic spiking and bursting. The discrete time dynamics allows to tune the time scale of the circuit to the needs of the specific application. Since the circuit described here only uses 18 MOS transistors, it offers new perspectives for building large networks of neurons in a single device. This is very relevant for the analysis of large networks of coupled neurons in order to investigate its dynamics over the network and its synchronization properties. 相似文献
12.
In this paper, the stability equation method is applied to the analysis of nonlinear systems with characteristics equations having complex coefficients. Three types of systems are studied: those with unstable open-loop poles, unstable characteristics roots or an equal number of open-loop poles and zeros. 相似文献
13.
以球面正压浅水方程显式能量守恒格式的设计为例,在不失动力学方程物理意义的情况下,给出南北极网格点上速度的表达式,以及其预报方程的差分格式.克服数学意义上的极点奇异问题,直接预报极点速度.数值试验表明,此方法简单易行,能合理描述极点速度及其变化. 相似文献
14.
15.
日益兴起的社会网络负功能研究,修正了以往过度重视积极效应的认识误区,逐渐成为社会网络研究的核心话题。本文基于企业层面,对相关领域的文献进行总结梳理后发现,企业社会网络的负功能可作用于微观、中观和宏观三个层面,分别表现为限制组织成员的创造力、导致企业面临"负债"困境、促使市场分割与地方保护主义的形成。在影响因素的研究中,现有的分析框架可归纳为网络结构主义和组织环境两种理论视角,网络排他性、过度嵌入、市场需求的不确定性、技术动荡、企业生命周期与战略目标均对社会网络负功能的发生产生重要作用。在此基础上,本文从研究视角、内容、方法和理论建构四个方面提出未来研究的发展方向。 相似文献
16.
In Part I of this paper we presented a formal procedure for determining the various state structures associated with any given digital network with the dimension of state vector equal to the number of dynamic elements in the network. For noncanonic networks, it is sometimes possible to find state structures with state vectors of reduced and even lowest dimension. Such a state structure is defined to be reduced state structure except for the case where state vector dimension is the lowest possible (the associated state structure is termed minimal). A graph-theoretic procedure for determing the existence of conditions under which a state structure can be simplified is outlined in this part of the paper. 相似文献
17.
《Journal of The Franklin Institute》2021,358(18):10193-10212
In this paper, the non-fragile state estimation problem is investigated for a class of continuous-time delayed complex networks. In the addressed complex network model, the outputs only from partial network nodes are used to fulfill the state estimation task. For improving the efficiency of resource utilization, a dynamic event-triggering mechanism is applied in the design of estimator, where an auxiliary time-varying parameter is introduced to dynamically modulate the triggering condition. Our intention is to obtain the gain parameters of the desired non-fragile state estimator, which can tolerate the norm-bounded gain perturbation. In virtue of a novel Lyapunov functional and matrix inequality technique, sufficient conditions are provided to ensure robustly exponential boundedness for estimation error dynamics, and gain matrices of the estimator are computed based on certain matrix inequalities. An illustrative simulation is presented to show the validity of the non-fragile estimator proposed. 相似文献
18.
M. Malek-Zavarei 《Journal of The Franklin Institute》1980,309(3):125-134
A class of unstable relay-controlled plants possessing one pole at the origin and two non-zero distinct real poles is studied. Cases corresponding to one or both non-zero poles in the right half-plane are considered. In each case a controller which simultaneously reduces the error and its first and second derivatives to zero in minimum time is designed. Also the class of admissible inputs is found which, after a minimum transient time, can be followed without any error. Through some linear transformations, it is shown that the equations of the switch curve and the switch surface can be made independent of the plant's constant gain and dependent only on the ratio of the non-zero pole values. It is established that in both regulating and tracking modes the error and its first and second derivatives can be reduced to zero with at most two switching reversals of the control provided that the initial values of error and/or its derivatives fall in a “controllable region”. 相似文献
19.
This paper addresses the emergence and development of firm-centred knowledge networks within learning and innovation systems in late-industrialising countries. A key contribution of the paper is conceptual and methodological: the development of an original typology of knowledge network properties to trace out changes in the form of networks as they evolve over time. A second contribution consists in providing an example of the application of the typology by examining the emergence and development of a firm-centred knowledge network in the case of Petrobras, the Brazilian oil company over more than 30 years between the late 1960s and the early 2000s. This demonstrates that the properties of Petrobras’ knowledge networks continuously evolved through a succession of stages towards (i) increasing intentionality in the management decision-making underlying network development, (ii) growing complexity and diversity in selected cognitive characteristics, and (iii) greater complementarity in the division of innovative labour between Petrobras and its network partners. These original results from applying the typology, in conjunction with retrospective historical methods, illustrate only one aspect of its potential value in the analysis of knowledge networks in late-industrialising economies: tracking out organisational evolution over long periods of time. Others include the comparative examination of network differences across different circumstances and the analysis of relationships between changes/differences in network properties and other characteristics of learning/innovation systems and their contexts. 相似文献
20.
组织合作网络结构对企业绩效的影响有两类相反的作用机制：网络闭合和网络开放。论文认为,哪种机制起作用取决于企业所面临的创新任务以及知识来源在网络中的位置。基于汤森路透、USPTO和Compustat三个数据库,论文构建1990-2001年生物技术和医药产业追踪数据,采用社会网络分析方法、固定效应和随机效应模型对此问题进行实证研究。结果发现,战略联盟网络密度增加和结构洞指标增加会负向影响企业技术创新数量,正向影响企业技术创新质量;网络结构调节着直接联盟关系和间接联盟关系对企业技术创新的影响。 相似文献