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31.
For an infinite-dimensional continuous (or discrete)-time linear system, based on the study of the representation of nonnegative solutions of the algebraic Riccati equation (ARE), we get some sufficient and necessary conditions for a nonnegative solution of (ARE) to be isolated in the set of all nonnegative solution of (ARE) with respect to the norm topology, the strong operator topology and weak operator topology, respectively. 相似文献
32.
Edgar Chávez José L. Marroquín Gonzalo Navarro 《Multimedia Tools and Applications》2001,14(2):113-135
Pivot-based algorithms are effective tools for proximity searching in metric spaces. They allow trading space overhead for number of distance evaluations performed at query time. With additional search structures (that pose extra space overhead) they can also reduce the amount of side computations. We introduce a new data structure, the Fixed Queries Array (FQA), whose novelties are (1) it permits sublinear extra CPU time without any extra data structure; (2) it permits trading number of pivots for their precision so as to make better use of the available memory. We show experimentally that the FQA is an efficient tool to search in metric spaces and that it compares favorably against other state of the art approaches. Its simplicity converts it into a simple yet effective tool for practitioners seeking for a black-box method to plug in their applications. 相似文献
33.
J. Gilewicz 《Cybernetics and Systems Analysis》2001,37(4):600-602
An asymptotic distribution of the instant of first failure in models with quick service, structural heterogeneity, and variable service discipline is investigated. 相似文献
34.
Jose S. Cánovas 《Dynamical Systems: An International Journal》2009,24(4):473-483
The topological entropy of a continuous transitive map f : ? → ? is studied. We find lower bounds for the topological entropy of f and prove that transitive real maps can have finite entropy. 相似文献
35.
Imtnan-Ul-Haque Qazi Author Vitae Olivier Alata Author Vitae Author Vitae Ahmed Moussa Author Vitae Author Vitae 《Pattern recognition》2011,44(1):16-31
This article presents a comparison of different color spaces including RGB, IHLS and L?a*b* for color texture characterization. This comparison is based on the fusion of the independent spatial structure and color feature cues. In IHLS and L*a*b*, two channel complex color images are created from the luminance and the chrominance values. For such images, two dimensional complex multichannel linear prediction models are used to perform parametric power spectrum estimation and the structure feature cues are computed from this estimated power spectrum. Quantitative comparison of auto spectra of luminance and combined chrominance channels for different color spaces is done. This comparison is based on the degree of decorrelation between luminance and chrominance information provided by different color space transformations. Three dimensional histograms are used as color feature cues. Then, to classify color textures, Kullback-Leibler divergence based symmetric distance measures are calculated for pure color, luminance structure and chrominance structure feature cues. Individual as well as combined effect of information from all feature cues on classification results is then compared for different color spaces and different color texture data sets. The proposed color texture classification method performs better than the state of the art methods in certain cases. The L*a*b* color space gives us a better characterization of the chrominance spatial structure as well as the overall spatial structure for all of the chosen data sets. Experimental results on pixel classification of color textures are also presented and discussed. 相似文献
36.
37.
Complicated nonlinear systems of pde with constraints (called pdae) arise frequently in applications. Missing constraints arising by prolongation (differentiation) of the pdae need to be determined to consistently initialize and stabilize their numerical solution. In this article we review a fast prolongation method, a development of (explicit) symbolic Riquier Bases, suitable for such numerical applications. Our symbolic-numeric method to determine Riquier Bases in implicit form, without the unstable eliminations of the exact approaches, applies to square systems which are dominated by pure derivatives in one of the independent variables. 相似文献
38.
该文从城市空间基本经济属性入手,在我国城市空间急剧膨胀的前提下,分析我国实现城市空间可持续利用的诸多动因,指出城市空间可持续利用是我国城市化可持续进行的重要内容。 相似文献
39.
The paper addresses the issue of how residual spaces are intervened upon through formal and informal processes. It argues that a profound understanding for the dynamics of informal interventions, denoted by appropriation, could enhance the performance of their formal peers.Adopting a qualitative approach, the paper departs from Lefebvre’s unitary theory of space and arrives at an analytical framework that helps to understand the appropriation processes in residual spaces. It, then, attempts to empirically challenge the applicability of this framework through analyzing a Cairene residual space that has undergone two cycles of intervention: a formal and informal one. 相似文献
40.
Application of Reproducing Kernel Hilbert Spaces to a Minimization Problem with Prescribed Nodes 下载免费PDF全文
The theory of reproducing kernel Hilbert spaces is applied to a minimization
problem with prescribed nodes. We re-prove and generalize some results previously
obtained by Gunawan et al. [2,3], and also discuss the Hölder continuity of the solution
to the problem. 相似文献