共查询到20条相似文献，搜索用时 15 毫秒
1.
Ren-hong Wang 《Journal of The Franklin Institute》2010,347(9):1782-1794
Piecewise constant orthogonal functions over triangular domains play an important role in many applications. In the present paper, some Haar and Walsh functions over triangular domains are constructed. Compared with the previously proposed Haar functions in [5], the new Haar functions take only integer. For any continuous function, the uniform convergence of the new Haar-Fourier series is proved. Moreover, based on the relation between the new Haar and Walsh functions, the uniform convergence of the Walsh-Fourier series is studied. Additionally, we obtain the relation between the Walsh functions in the two different orders, Paley order and Hadamard order, which have not been discussed previously. 相似文献
2.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
北京市耕地多功能空间分异及其社会经济协调模式解释 总被引：15，自引：0，他引：15
以北京市为例,在解析识别耕地功能表征因子的基础上,分别对北京13个区县(不包括中心城区)耕地的生产、生态、社会功能进行评价,利用GIS反映多功能的空间分布形态,并通过信息熵模型对耕地多功能与社会经济的空间相关性进行测算,讨论各区县耕地多功能与其经济社会发展的互动关系以及发展阶段的协调模式。本文旨在揭示北京市耕地多功能在社会经济影响下的空间分异特征,为制定科学的耕地多功能利用布局方案提供理论依据。研究结果表明:北京市各区县经济社会发展水平与耕地多功能的空间相关性较强,具有明显的空间分异特征;此外在经济与政策的共同驱动下,多功能与经济的组合模式随着经济发展经历高生产-中社会-低生态的正三角形态向低生产-中社会-高生态的倒三角形态演变的一般过程。 相似文献
11.
S.G. Tzafestas 《Journal of The Franklin Institute》1978,305(4):199-220
This paper considers the problem of identifying the parameters of dynamic systems from input-output records. Both lumped-parameter and distributed-parameter systems, deterministic and stochastic, are studied. The approach adopted is that of expanding the system variables in Walsh series. The key point is an operational matrix P which relates the coefficient matrix Г of the Walsh series of a given function with the coefficient matrix of its first derivative. Using this operational matrix P one overcomes the necessity to use differentiated data, a fact that usually is avoided either by integration of the data or by using discrete-time models. Actually, the original differential input-output model is converted to a linear algebraic (or regression) model convenient for a direct (or a least squares) solution. A feature of the method is that it permits the identification of unknown initial conditions simultaneously with the parameter identification. The results are first derived for single-input single-output systems and then are extended to multi-input multi-output systems. The case of non-constant parameters is treated by assuming polynomial forms. Some results are also included concerning the identification of state-space and integral equation models. The theory is supported by two examples, which give an idea of how effective the method is expected to be in the real practice. 相似文献
12.
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
13.
提出了带记忆组合器的非线性复杂度和相关免疫阶的概念 .通过分析 ,发现它们是设计带记忆组合器的重要准则 ;另一条设计准则是输出函数和状态函数的平衡性 .根据这些新的带记忆组合器的设计准则 ,构造了一类具有很好性质的密钥流生成器 .它的相关免疫阶可以是 [0 ,n - 1 ]中的任意一个整数 ,它的非线性度可以通过调整一些布尔函数获得 . 相似文献
14.
布尔函数是否存在低次零化子,是代数攻击成功与否的关键。在定义了零化子相关度基础上,给出确定布尔函数存在低次零化子的算法。其核心思想是根据布尔函数与具有低次零化子函数之间的零化子相关度来判断布尔函数是否存在低次零化子。相对于直接计算布尔函数的低次零化子复杂度明显降低。 相似文献
15.
A finite set expansion method is presented for the suboptimal control of linear time-varying systems with both complete and incomplete state availability. By projecting the dynamical model of the system into a subspace of Walsh signals, we are able to implement the control by employing a computational method which involves constant coefficients. The method is illustrated by an example. 相似文献
16.
城乡转型发展进程中的农村居民点用地调整应加强对其空间形态的系统认识与分类研究。本文从“点”-“面”耦合的角度构建农村居民点空间形态概念模型,基于“2+3”式抽样法选取山东省不同区域的5个典型乡镇及其内部的15个典型村庄作为研究对象,分别应用“点”属性的规模、形状和密度指标划分农村居民点类型,利用“面”属性的生产、生活和生态指标剖析农村居民点功能,进而通过对比分析揭示农村居民点“点-面”形态耦合特征。研究发现：①在“点状”形态上,典型乡镇的农村居民点规模差异较大,密度相对集聚,形状偏于不规则;经济落后地区和山区的农村居民点组合类型比较单一,经济发达和平原地区的农村居民点组合类型多样。②在“面状”形态上,农村居民点整体表现为“生产功能较好,生活功能差,生态功能一般”的特征;随着镇域内区位优势的衰减,典型村庄的生产功能逐渐降低并趋于均衡化,生活功能逐渐降低但分化程度更加剧烈,生态功能也逐渐降低但缩减幅度相对均衡。③在“点-面”形态耦合上,大规模-集聚型农村居民点的生活和生态功能偏强,小规模-分散型农村居民点的生活功能稍强,大规模-分散-不规则型农村居民点各项功能均较弱,这种组合类型和功能关系之间的关联性是外部性要素导向下农村居民点内部要素自组织演化的体现。 相似文献
17.
广州市土地利用多功能的空间差异及影响因素分析 总被引：7，自引：0，他引：7
随着经济社会发展和土地利用格局变化,区域土地利用功能的多元化和空间差异特征日益明显。以县域为评价单元,从可持续发展的经济、环境和社会三大维度构建土地利用多功能评价指标体系,采用改进突变级数法评价广州市土地利用多功能水平,并对其空间差异及影响因素进行分析。结果表明：①2005-2011年广州市土地利用总功能在所有区县几乎均增强,空间差异缩小,并呈现沿中心城区向外逐渐增强的态势。在总功能构成中,县级市和远郊区的农业生产和环境功能比重较大,中心城区和近郊区的社会、经济发展与交通功能占比较大。②单项功能在所有区县几乎均增强,空间差异有所变小。经济和社会功能由中心城区向外逐渐减弱,环境功能由中心城区向外逐渐增强。③农业生产和资源供给功能在所有区县均减弱,空间差异有所扩大,其它子功能几乎均增强,空间差异有所缩小。农业生产、资源供给和环境净化功能县级市和远郊区高于近郊区和中心城区,生态维持功能北部区县高于南部区县,文化休闲功能空间分异规律不明显,其它子功能基本是中心城区和近郊区高于远郊区和县级市。④影响土地利用多功能的因素主要包括自然资源禀赋、社会经济因素和政策因素等方面。 相似文献
18.
基于村域多功能视角的乡村振兴策略——以鄂西郧阳山区为例 总被引：1，自引：0，他引：1
乡村振兴战略是新时代背景下中国妥善解决三农问题的重大战略决策。村域多功能发展及管理是实现乡村全面振兴的有效契合点和新路径。本文通过系统建立评价指标体系,应用综合评价法对研究区村域各项功能及多功能指数展开评价,利用纵横对比法识别村域主导功能及短板功能,确定各村域的发展类型,并提出了差异化发展路径。研究结果表明：①村域农业生产功能、居住生活功能、社会保障功能及生态保育功能的空间分异明显;②山区村域多功能指数整体不高,且各村域差异不大;③通过识别各村域主导功能及短板功能,建立发展类型划分规则,将研究区划分为极化发展型、主导发展型及综合发展型3大发展类型,并进一步将极化发展型细分为4类发展亚型,将主导发展类型分为3类发展亚型,最终对各类发展类型提出了相应的发展策略。本文从村域多功能视角探索乡村振兴策略,为中国新时代乡村振兴战略提供借鉴,也有利于拓展地域多功能研究视角,进一步丰富多功能研究理论框架。 相似文献
19.
生态多样性与生态系统服务功能的多尺度比较分析——以内蒙古自治区锡林郭勒盟白音锡勒的草地生态系统为例 总被引：1，自引：0，他引：1
本文回顾了生态多样性空间尺度效应的研究成果，分析了生态多样性与生态系统服务功能间相互关系研究中存在的方法问题。在此基础上，以内蒙古自治区锡林郭勒盟的白音锡勒草地生态系统为例，运用多尺度多样性模型、香侬模型和辛普森模型对不同空间分辨率和尺度上对生态多样性及其与生态系统服务功能的关系进行了对比分析。结果表明，多尺度多样性模型模拟得到的景观元多样性严格地随着空间分辨率的降低而下降，表现出明显的规律性，说明多尺度多样性模型更适于在多个空间尺度上的运用；空间分辨率的变化对生态多样性与草地最大地上生物量和荒漠化面积之间的相互关系产生非线性影响。 相似文献
20.
提出一种应用于脉冲超宽带相关接收机的新型门控积分方法,它利用简单的线性时不变系统实现带清除的积分．这种门控积分方法简化了系统结构,易于实现．论文引入误差函数和干扰函数评价等效积分性能,还以二阶低通滤波器为例,给出了等效积分应用在模拟匹配相关时的性能计算结果,表明等效方法完全适用于脉冲超宽带模拟相关接收机． 相似文献