共查询到20条相似文献，搜索用时 46 毫秒
1.
P.N. Paraskevopoulos 《Journal of The Franklin Institute》1983,316(2):135-157
The problems of identification, analysis and optimal control have been recently studied via orthogonal functions. The particular orthogonal functions used up to now are the Walsh, the block-pulse and the Laguerre functions. In this paper, the Chebyshev functions are introduced and solutions for the aforementioned problems are established. The algorithms proposed are analogous to those already derived for the Walsh, block-pulse and Laguerre functions. The Chebyshev series approach presented here appears to have certain advantages over other orthogonal series, and they may therefore be more suitable for the study of the problems of identification, analysis and optimal control. 相似文献
2.
A new method is employed to identify the unknown parameters of a bilinear system. This method expands the system input and output by block pulse functions and reduces the original identification problem to an algebraic form. Furthermore, the dyad formed by block pulse functions and its integral are in diagonal forms, whereas the integration of the “triple-product” matrix can be reduced to the upper triangular form. Consequently, only very few calculations are required to find the solution for the algebraic equation. Two examples are given to show that the use of this method is considerably more economical in computation time than the use of Walsh function expansion. 相似文献
3.
This paper establishes a clear procedure for the variational problem solution via the Walsh functions.technique. First the Walsh functions are introduced and their properties briefly summarized. Then an operational matrix is derived for integration use. The variational problems are solved by means of the direct method using the Walsh series. An illustrative example and a practical application to a heat conduction problem are included. 相似文献
4.
The Walsh operational matrix for performing integration and solving state equations is generalized to fractional calculus for investigating distributed systems. A new set of orthogonal functions is derived from Walsh functions. By using the new functions, the generalized Walsh operational matrices corresponding to √s, √(s2+ 1), e-s and e-√s etc. are established. Several distributed parameter problems are solved by the new approach. 相似文献
5.
B.G. Sloss 《Journal of The Franklin Institute》2003,340(1):25-41
A new method for the numerical solution of linear and non-linear Volterra integral equations, using the discontinuous wavelet packets known as the Walsh functions, is proposed and investigated. Sufficient conditions for the method to converge are derived and a priori error estimates are obtained. Given sufficient regularity conditions on the integral equation, the method is shown to be locally of order two. 相似文献
6.
Ta-Mu Chien 《Journal of The Franklin Institute》1976,301(4):371-377
The correlation function of two Walsh functions appears in image processing, signal multiplexing, detection and spectral analysis using Walsh functions. Though Walsh functions are two-valued, their correlation functions are real-valued and rather difficult to evaluate. A recursive formula is developed in this paper to evaluate the correlation functions. Some other properties of the correlation function are also discussed. 相似文献
7.
无穷级数是高等数学的一个重要组成部分,形式上为相对独立的一块内容,理论上更为抽象,学生在学习这章内容时大多感觉比较困难,在判别级数敛散性时往往思路不清。针对这种状况,本文谈谈几点看法院（1）教师在开始讲授这章内容时,应该向学生介绍清楚学习本章内容的作用所在;（2）对于这章内容的教学,教师应该有所侧重讲解,讲课的顺序也不能完全同于教材的排版顺序;（3）在讲授正课时,教师应该对学生讲解最常用而又有简单有顺序的敛散性判别法。 相似文献
8.
Zvezdan M. Marjanović Goran T. Djordjević Gradimir V. Milovanović 《Journal of The Franklin Institute》2018,355(2):965-980
In this paper, we analyze detection of multilevel phase-shift keying (MPSK) signals transmitted over a Gamma shadowed Nakagami-m fading channel. We derive novel analytical expression, in terms of Meijer’s G function, for Fourier coefficients of the probability density function of the received signal composite phase. Under the assumption of the imperfect reference signal extraction in the receiver, which is performed from the pilot signal, the analytical expression is derived for the symbol error probability (SEP) in the form of convergent series. The existence of the error floor is identified, and expression for its computation is provided. Mathematical proofs for convergence of Fourier series are provided for both SEP and SEP floor, and novel expressions of upper bounds for truncation errors are derived in terms of elementary mathematical functions. The convergence rate of the derived expressions is examined. Numerical results are confirmed independently by Monte-Carlo simulations. 相似文献
9.
部分Bent函数的几种构造方法 总被引：1，自引：0，他引：1
给出了部分Bent函数几种一般性构造方法,同时得到了由上述方法所构造出的部分Bent函数的Walsh循环谱特征.特别给出了由变元个数少的Bent函数构造变元个数多的部分Bent函数的一般方法,由此方法可构造出大量的部分Bent函数. 相似文献
10.
网络秩序监控体系的构建是建设和谐网络社会的重要内容。网络秩序具有内生性、有机性和复合性特点。网络秩序监控的目的是为了最大限度地遏制网络失范现象的泛滥。文章提出了网络秩序监控体系的"三三制"模型。这一模型是以政府为主导的多元化、全方位监控体系,它包括政府、网络媒体、网民三大监控主体,监控手段包括法律监控、技术监控、道德监控三方面,从信源、信道、信宿3个环节进行全方位监控。由此形成"信源——政府——法律"、"信道——网站——技术"和"信宿——网民——道德"3个维度构成的"三三制"监控体系。这3个维度之间的关系并不是"各自为战"的分立关系,而是在政府主导下协同作战的交叉统合关系。 相似文献
11.
《Research Policy》2022,51(9):104160
While previous comparative research has identified the formal institutional conditions that differentiate countries on their degree of informal entrepreneurship, this paper examines the characteristics that shape cross-national diversity in its type. Based on a series of fuzzy-set qualitative comparative analyses (fs/QCA) of 138 country cases, we find evidence of causal heterogeneity in the configuration of institutional conditions associated with entrepreneurial outcomes that are informal and growth-oriented and those that are informal and subsistence-oriented. Given our results, we propose that the formal institutional-based conditions that differentiate between types of informal sectors are best identified by the conjoint mixture of strength and weakness of state capabilities across multiple domains, rather than by uniform weakness, or voids, along all state functions. In our discussion, we explore the implication of our configurational-based findings for the comparative analysis of national systems of informal entrepreneurship and for the tailoring of policies to account for the multiple institutional-based pathways by which entrepreneurs come to enter into the informal economy. 相似文献
12.
《Journal of The Franklin Institute》2022,359(7):3183-3209
In order to find the theoretical solution of a dynamic Sylvester equation (DSE) in noisy environment, a robust fast convergence zeroing neural network (RFCZNN) is proposed in this paper. Unlike the original zeroing neural network (ZNN) model with existing activation functions (AF), by introducing a new AF, the proposed RFCZNN model guarantees fixed-time convergence to theoretical solution of DSE and robustness against noise simultaneously. The effectiveness and robustness of the proposed RFCZNN model are investigated in theory and demonstrated through simulation results. In addition, its effectiveness and robustness are further verified by a successful robotic trajectory tracking application in noisy environment. 相似文献
13.
主要探讨了基于MD方式构造hash函数时平衡度的保持问题,说明了压缩函数满足何种条件时hash函数能够取得最好的平衡度,提出了局部平衡度的概念,并利用此概念解决了压缩函数局部平衡度与Hash函数平衡度的关系的问题。这对于未来的hash函数的设计有非常重要的意义。 相似文献
14.
《Information processing & management》2023,60(1):103123
Aligning time series of different sampling rates is an important but challenging task. Current commonly used dynamic time warping methods usually suffer from pathological temporal singularity problem. In order to overcome this, we transform the alignment task to a spatial-temporal multi-objective optimization (MOO) problem. Existing MOO algorithms are always inefficient in finding Pareto optimal alignment solutions due to their insufficiency in maintaining convergence and diversity among the obtained Pareto solutions. In light of this, we propose a novel and efficient MOO algorithm Cell-MOWOA which integrates Cellular automata with the rising Whale Optimization Algorithm to find Pareto optimal alignment solutions. Innovative multi-variate non-linear cell state evolutionary rules are designed within Pareto solution external archive to improve the convergence and diversity of the Pareto solutions, and novel whale population updating mechanism is designed to accelerate the convergence to the Pareto front. Besides, new integer whale updating mechanism is presented to transform real-number whale solutions to integer whale solutions. Experimental results on 85 gold-standard UCR time series datasets showed that Cell-MOWOA outperformed six state-of-the-art baselines by 24.53% in average in increasing alignment accuracy and 42.66% in average in reducing singularity. Besides, it achieved outstanding runtime efficiency, especially on long time series datasets. 相似文献
15.
提出一种基于游程统计和Walsh谱能量分布的调色板图像隐写分析方法,利用调色板颜色的奇偶值(parity value,P值)构造P值图像,通过游程统计和Walsh变换提取出46维特征,并用校准技术削弱载体图像差异对分析统计量的干扰.实验表明,该方法适用于EzStego、分量和以及最佳奇偶隐写等调色板图像隐写算法,比奇异颜色分析准确. 相似文献
16.
《Journal of The Franklin Institute》2022,359(18):10849-10866
This paper considers neural network solutions of a category of matrix equation called periodic Sylvester matrix equation (PSME), which appear in the process of periodic system analysis and design. A linear gradient-based neural network (GNN) model aimed at solving the PSME is constructed, whose state is able to converge to the unknown matrix of the equation. In order to obtain a better convergence effect, the linear GNN model is extended to a nonlinear form through the intervention of appropriate activation functions, and its convergence is proved through theoretical derivation. Furthermore, the different convergence effects presented by the model with various activation functions are also explored and analyzed, for instance, the global exponential convergence and the global finite time convergence can be realized. Finally, the numerical examples are used to confirm the validity of the proposed GNN model for solving the PSME considered in this paper as well as the superiority in terms of the convergence effect presented by the model with different activation functions. 相似文献
17.
18.
Mohammad Maqusi 《Journal of The Franklin Institute》1980,310(1):65-75
This paper discusses the identification problem for a class of nonlinear systems. A member of this class may be represented by a single-valued power-law type nonlinearity preceded and succeeded by linear dyadic invariant systems. Such an arrangement allows for a Voltera functional series representation. The identification problem is then concerned with the specification of the associated Voltera kernels.Two approaches are presented for dealing with this problem. Both approaches are, however, based on Walsh function techniques. The first approach relies on direct output measurements when the input is a Walsh function. This approach is suitable for a deterministic case. The second approach assumes ergodic processes for the input. Based on measurements drawn from an input-output dyadic correlation function, determination of the Voltera kernels is made. 相似文献
19.
Walsh product matrix is formed by the multiplication of Walsh vector and its transpose. The operation of Walsh product matrix on a coefficient vector equals the product of a coefficient matrix and a Walsh vector. This unique property of Walsh function is used to determine the unknown parameters of a general bilinear system from the input-output data. An example with satisfactory result is given. 相似文献
20.
技术融合是指原本相互独立的技术跨越其边界相互交叉渗透从而催生出新兴技术的现象，作为产业变革的核心动力其被认为是促进新兴产业形成及新产品开发的重要因素。本研究通过收集中国新能源汽车产业所有企业在2005至2017关于新产品的面板数据，通过专利IPC号的耦合结构与替代关系分别对互补性和替代性技术融合进行测度，并采用负二项固定效应回归模型，实证分析了跨领域技术融合与企业新产品开发绩效之间的关系。研究结果表明：当企业聚焦于特定领域采取替代性技术融合时，替代性技术融合强度越大越有利于提升企业新产品数量及新产品进入市场的速度；而当企业跨越多个领域采取互补性技术融合时，一开始有利于提升企业新产品数量及新产品进入市场的速度，但后期将不利于企业新产品数量与新产品进入市场速度的进一步提升。 相似文献