共查询到20条相似文献，搜索用时 125 毫秒
1.
This paper presents the central finite-dimensional H∞ filter for nonlinear polynomial systems with multiplicative noise, that is suboptimal for a given threshold γ with respect to a modified Bolza-Meyer quadratic criterion including the attenuation control term with the opposite sign. In contrast to the previously obtained results, the paper reduces the original H∞ filtering problem to the corresponding optimal H2 filtering problem, using the technique proposed in [1]. The paper presents the central suboptimal H∞ filter for the general case of nonlinear polynomial systems with multiplicative noise, based on the optimal H2 filter given in [31]. The central suboptimal H∞ filter is also derived in a closed finite-dimensional form for third (and less) degree polynomial system states. Numerical simulations are conducted to verify performance of the designed central suboptimal filter for nonlinear polynomial systems against the central suboptimal H∞ filters available for polynomial systems with state-independent noise and the corresponding linearized system. 相似文献
2.
A simple design method for the cosine-modulated filter banks using weighted constrained least square technique 总被引：1，自引：0，他引：1
This paper presents a simple and efficient design method for cosine-modulated filter banks with prescribed stopband attenuation, passband ripple, and channel overlap. The method casts the design problem as a linear minimization of filter coefficients such that their value at ω=π/2M is 0.707, which results in a simpler, more direct design procedure. The weighted constrained least squares technique is exploited for designing the prototype filter for cosine modulation (CM) filter banks. Several design examples are included to show the increased efficiency and flexibility of the proposed method over the exiting methods. An application of the proposed method is considered in the area of sub-band coding of the ECG and speech signals. 相似文献
3.
This paper is concerned with the network-based H∞ fuzzy filtering for non-linear systems with parameter uncertainties under a novel adaptive discrete event-triggered communication scheme (DETCS). Based on interval type-2 (IT2) Takagi–Sugeno (T–S) fuzzy model, the non-linear systems with parameter uncertainties are represented as a class of IT2 T–S fuzzy systems. In the design process, a novel adaptive DETCS is proposed to reduce the usage of system resources and adapt the variation of plant output, and a novel networked IT2 T–S fuzzy filter is applied to improve the flexibility of filter design. By employing the time-delay systems modeling method, the filtering-error-system is modeled as a class of interval time-varying delayed IT2 T–S fuzzy systems with asynchronously and imperfectly matched membership functions, and further conditionally expressed as a favorable form. Then, some relaxed stability criteria are established to determine that this class of delayed IT2 T–S fuzzy systems is asymptotically stable with a prescribed H∞ disturbance attenuation performance. Also, the co-design of parameter matrices of adaptive DETCS and filter is implemented. Finally, two numerical examples are provided to demonstrate the effectiveness of the proposed method. 相似文献
4.
In this paper, an improved Exponential window is developed for designing M-channel cosine-modulated pseudo QMF banks. The Exponential window is modified by adding third parameter (ρ), which improves the spectral characteristic of a window in terms of smaller ripple ratio, wider main lobe width with improved side lobe roll-off ratio. When it is exploited for designing multi-channel cosine modulated filter banks, the modified Exponential window gives better performance for higher band as compared to lower band. In addition to this, the modified Exponential window performs better performance at lower stopband attenuation. When compared with modified Cosh and Kaiser windows, the modified Exponential windows performs better in terms of amplitude distortion, aliasing distortion (AD) and computational time (CPU time) for the same design specifications. Several examples are included to illustrate the effectiveness of this window in the field multirate systems designing. 相似文献
5.
In this paper, the event-triggered non-fragile H∞ fault detection filter is designed for a class of discrete-time nonlinear systems subject to time-varying delays and channel fadings. The Lth Rice fading model is utilized to reflect the actual received measurement signals, and its channel coefficients own arbitrary probability density functions on interval [0,1]. The event-based filter is constructed to reduce unnecessary data transmissions in the communication channel, which only updates the measurement signal to the filter when the prespecified “event” is triggered. Multiplicative gain variations are utilized to describe the phenomenon of parameter variations in actual implementation of the filter. Based on Lyapunov stability theory, stochastic analysis technology along with linear matrix inequalities (LMIs) skills, sufficient conditions for the existence of the non-fragile fault detection filter are obtained which make the filtering error system stochastically stable and satisfy the H∞ constraint. The gains of the filter can be calculated out by solving the feasible solution to a certain LMI. A simulation example is given to show the effectiveness of the proposed method. 相似文献
6.
This paper focuses on the problem of robust H∞ filter design for uncertain systems with time-varying state and distributed delays. System uncertainties are considered as norm-bounded time-varying parametric uncertainties. The delays are assumed to be time-varying delays being differentiable uniformly bounded with delay-derivative bounded by a constant, which may be greater than one. A new delay-derivative-dependent approach of filter design for the systems is proposed. A novel Lyapunov-Krasovskii functional (LKF) is employed, and a tighter upper bound of its derivative is obtained by employing an inequality and using free-weighting matrices technique, then the proposed result has advantages over some existing results, in that it has less conservatism and it enlarges the application scope. An improved sufficient condition for the existence of such a filter is established in terms of linear matrix inequality (LMI). Finally, illustrative examples are given to show the effectiveness and reduced conservatism of the proposed method. 相似文献
7.
Yingchun Wang Longfei Zheng Huaguang Zhang Xiangpeng Xie 《Journal of The Franklin Institute》2018,355(17):8392-8411
This paper investigates the problem of event-triggered fault detection filter design for nonlinear networked control systems with both sensor faults and process faults. First, Takagi–Sugeno (T–S) fuzzy model is utilized to represent the nonlinear systems with faults and disturbances. Second, a discrete event-triggered communication scheme is proposed to reduce the utilization of limited network bandwidth between filter and original system. At the same time, considering network-induced delays and event-triggered scheme, a novel T–S fuzzy fault detection filter is constructed to generate a residual signal, which has nonsynchronous premise variables with the original T–S fuzzy system. Then, the fuzzy Lyapunov functional based approach and the reciprocally convex approach are developed such that the obtained sufficient conditions ensure that the fuzzy fault detection system is asymptotically stable with H∞ performance and is less conservative. All the conditions are given in terms of linear matrix inequalities (LMIs), which can be solved by LMI tools in MATLAB environment. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed results. 相似文献
8.
This paper investigates the problem of event-triggered filter design for nonlinear networked control systems (NCSs) in the framework of interval type-2 (IT2) fuzzy systems. A novel IT2 fuzzy filter for ensuring asymptotic stability and H∞ performance of filtering error system is proposed, where the premise variables are different from those of the fuzzy model. Attention is focused on solving the problem of event-triggered filter design subject to parameter uncertainties, data quantization, and communication delay in a unified frame. It is shown that the proposed event-triggered filter design communication mechanism for IT2 fuzzy NCSs has the advantage of the existing event-triggered approaches to reduce the utilization of limited network resources and provides flexibility in balancing the tracking error and the utilization of network resources. Finally, simulation example is given to validate the advantages of the presented results. 相似文献
9.
A novel H∞ filter design methodology has been presented for a general class of nonlinear systems. Different from existing nonlinear filtering design, the nonlinearities are approximated using neural networks, and then are modeled based on linear difference inclusions, which makes the structure of the desired filter simpler and parameter turning easier and has the advantages of guaranteed stability, numeral robustness, bounded estimation accuracy. A unified framework is established to solve the addressed H∞ filtering problem by exploiting linear matrix inequality (LMI) approach. A numerical example shows that the filtering error systems will work well against bounded error between a nonlinear dynamical system and a multilayer neural network. 相似文献
10.
信息化标准是解决系统集成、数据共享的基本途径。本文以煤炭企业为切入点探讨信息化标准的有效性。基于煤企在引入一系列信息系统后产生的对信息化标准的客观需求,本文将信息化标准看作一个系统,从煤企信息系统建设的5个阶段以及信息化标准系统3个阶段出发,分析了有效的煤企信息化标准应该同时具有适应性A（adaptability）、实用性F（functionality）、可实现性R（realizability）、参与性J（joint）、科学性S（scientificity）、前瞻性P（prospective）等特性,在此基础上提出了煤企信息化标准系统有效性的影响因素并给出了因素关系图和关系链图。最后,构建了标准有效性的计算公式。 相似文献
11.
《Journal of The Franklin Institute》2019,356(18):11561-11580
This paper addresses the robust H∞ filter design problem for a class of uncertain fuzzy neutral stochastic system with time-delay through Takagi–Sugeno (T–S) fuzzy model. By constructing an augmented Lyapunov–Krasovskii functional, some novel delay-dependent stability criteria for uncertain fuzzy neutral stochastic system with time varying delay are obtained in terms of linear matrix inequalities. By using the integral inequality in the neutral stochastic setting combined with delay decomposition approach, the H∞ fuzzy filter is designed to guarantee the corresponding filtering error systems robustly asymptotically stable with a specified H∞ performance index. At last, two numerical examples are presented to show the less conservatism than the previous results. 相似文献
12.
In this paper, the problem of H∞ filtering for neutral systems with mixed time-varying delays and nonlinear perturbations is investigated. Some new delay-dependent sufficient conditions are presented to ensure that the filtering error system is asymptotically stable with a prescribed level of H∞ noise attenuation. In addition, the design procedures for the existence of such filter are presented in terms of a set of linear matrix inequalities (LMIs). Slack variables and convex combination technique are adopted to reduce the conservatism of obtained results. Finally, three numerical examples are given to illustrate the effectiveness of the proposed method. 相似文献
13.
Government R&D subsidies as a signal for private investors 总被引：1，自引：0，他引：1
Robin Kleer 《Research Policy》2010,39(10):1361-1374
Government subsidies for R&D are intended to promote projects with high returns to society but too little private returns to be beneficial for private investors. This may be caused by spillovers or a low appropriability rate. Apart from the direct funding of these projects, government grants may serve as a signal for good investments for private investors. We use a simple signaling model with different types of R&D projects to capture this phenomenon. The agency has a preference for basic research projects as they promise high expected social returns, while banks prefer applied research projects with high private returns. In a setup where the subsidy can only be used to distinguish between basic and applied research projects, government agency’s signal is not very helpful for banks. However, if the subsidy is accompanied by a quality signal, it can lead to increased or better selected private investments. 相似文献
14.
The polynomial solutions of the equation fy″ + gy′ + λy = 0 are obtained and classified for f, g, and λ certain second-degree, first-degree, and zero-degree polynomials, respectively. Applications are given illustrating the use of these polynomials in the construction of amplitude functions and system functions and in tree counting. In particular, all-pole and rational filter functions are considered which include as special cases the Chebyshev, Butterworth, elliptic, Bessel, and various transitional filter functions. 相似文献
15.
The rate of inflation in R&D is very difficult to measure. The official government statistics in the United States use the GNP deflator to deflate R&D expenditures. Little is known about the extent to which price indexes for R and D inputs, if they were constructed in various industries, would differ from the GNP deflator. This paper reports the findings of a study that attempts to fill this important gap. Laspeyres price indexes are presented both for R and D inputs and for inputs used in other stages of the innovation process. Also, price indexes for R and D inputs are constructed, assuming that the relevant production function is Cobb-Douglas. On the basis of the results, we estimate the extent and direction of the errors in the official R&D statistics due to the use of the GNP deflator.Our findings, based on detailed data obtained from firms accounting for about one-ninth of all company-financed R&D in the U.S., indicate that the GNP deflator underestimated the rate of price increase for R&D inputs during 1969–1979 in practically every industry we studied. The bulk of the apparent increase in real R&D in these industries (which was relatively modest in any event) seems to have been due to the inadequacies of the GNP deflator. One important moral seems to be that more attention and resources should be devoted to the construction of better price indexes for R&D. 相似文献
16.
《Journal of The Franklin Institute》2019,356(17):10335-10354
This paper is devoted to investigate the designs of the event-based distributed state estimation and fault detection of the nonlinear stochastic systems over wireless sensor networks (WSNs). The nonlinear stochastic systems as well as the filters corresponding to the multiple sensors are represented by interval type-2 Takagi–Sugeno (T–S) fuzzy models. (1) A new type of fuzzy distributed filters based on event-triggered mechanism is established corresponding to the nodes of the WSN. (2) The overall stability and performance, that is mean-square asymptotic stability in H∞ sense, of the event-driven fault detection system is analyzed based on Lyapunov stability theory. (3) New techniques are developed to cope with the problem of parametric matrix decoupling for solving the distributed filter gains. (4) Finally, the desired event-based distributed filter matrices are designed subject to the numbers of the fuzzy rules and a series of matrix inequalities. A simulation case is detailed to show the effectiveness of the presented event-based distributed fault detection filtering scheme. 相似文献
17.
《Journal of The Franklin Institute》2014,351(12):5340-5357
This paper investigates the mean-square filtering problem for a linear time delay systems with Gaussian white noises. The obtained solution contains a sliding mode term, signum of the innovations process. It is demonstrated that the estimate produced by the designed filter generates the mean-square estimate, which has the same minimum estimation-error variance as the best estimate given by the classical Kalman–Bucy filter. The theoretical result is applied to an illustrative example: the tryptophan operon of E. coli, verifying the performance of the designed filter. It is demonstrated that the estimates produced by the designed sliding-mode mean-square filter and the Kalman–Bucy filter yield the same estimation-error variance. Simulation graphs demonstrate the better performance of the designed sliding-mode filter and show the potential of the proposed new filter. 相似文献
18.
We propose an extension of the Gans-Stern [Gans, J.S., Stern, S., 2003. The product market and the market for “ideas”: commercialization strategies for technology entrepreneurs. Research Policy 32 (2), 333-350] framework that includes entry by existing firms. An incumbent firm possessing complementary assets and strong appropriability is in a formidable position [Teece, D.J., 1986. Profiting from technological innovation: implications for integration, collaboration, licensing, and public policy. Research Policy 15 (6), 285-305]. However, a de alio entrant can leverage complementary assets to enter along a new technological trajectory, and then develop appropriability. We illustrate how several mobile telecommunications firms (Ericsson, Nokia and Samsung) pursued this strategy to catch up with the market leader (Motorola). We also identify several shortcomings in Motorola's approach: it was too inward-looking in developing technologies, but ironically not inward-looking enough in exploiting its most valuable patents. 相似文献
19.
20.
In this paper, the robust fault detection filter (RFDF) design problems are studied for nonlinear time-delay systems with unknown inputs. Firstly, a reference residual model is introduced to formulate the robust fault detection filter design problem as an H∞ model-matching problem. Then appropriate input/output selection matrices are introduced to extend a performance index to the time-delay systems in time domain. The reference residual model designed according to the performance index is an optimal residual generator, which takes into account the robustness against disturbances and sensitivity to faults simultaneously. Applying robust H∞ optimization control technique, the existence conditions of the robust fault detection filter for nonlinear time-delay systems with unknown inputs are presented in terms of linear matrix inequality (LMI) formulation, independently of time delay. An illustrative design example is used to demonstrate the validity and applicability of the proposed approach. 相似文献