排序方式: 共有21条查询结果,搜索用时 286 毫秒
1.
S. Kh. Aranson V. Z. Grines V. A. Kaimanovich 《Journal of Dynamical and Control Systems》2003,9(4):455-468
We obtain a complete classification of supertransitive 2-webs on a closed oriented surface of genus p 1 in terms of asymptotic directions of leaves on the universal covering surface and represent all topological classes of 2-webs by means of compatible pairs of transversal perfect geodesic laminations. 相似文献
2.
3.
In this paper, motivated by the restrictive conditions required to obtain an exact chained form, we propose a quadratic normal
form around a one-dimensional equilibrium submanifold for systems which are in a chained form in their first approximation.
In the case considered here, in contrast to the case of approximated feedback linearization, not all the state and input components
have the same approximation meaning. Because of this, we use a very simplified version of dilation, which is a useful way
to design a homogeneous control law for driftless systems.
Date received: December 2, 1999. Date revised: October 24, 2001. 相似文献
4.
We will consider a convex subset of a metric linear space and a certain group of actions G on this set, that allow us to define the notion of Haar zero measure on sets that have zero Haar measure for the translation (by adding) invariant HSY prevalence theory. In this way, we will be able to define the meaning of G-prevalent set according to the pioneering work of Christensen. Our setting considers problems which take into account the convex structure and this is quite different from the previous results on prevalence which consider basically the linear additive structure. In this setting, we will show a kind of quantitative Kupka–Smale theorem, and also we generalize a result about rotation numbers which was first considered by J.-C. Yoccoz (and, also by M. Tsujii). Among other things we present an estimation of the amount of hyperbolicity in a setting that we believe was not considered before. 相似文献
5.
提出了与双障碍问题等价的非光滑方程的类梯度算法 ,并在一定条件下证明了该算法的收敛性定理 .数值试验表明该算法是有效的 . 相似文献
6.
7.
The paper is mainly devoted to the robust stability problem of non-linear QFT designs. The problem is first formulated for SISO non-linear systems, limited in practice to linear-memoryless sector-bounded non-linear interconnections, and in an I/O stability sense. The work investigates several possible robust adaptations of the Circle Criterion, depending on the type of resulting interconnection of linear and non-linear blocks, appearing in the feedback system. Also, the use of the Popov Criterion is investigated as an alternative less conservative than the Circle Criterion in some cases. The proposed techniques are given in usual QFT language, expressed as frequency conditions or boundaries in the Nichols Chart, allowing an easy integration with other design objectives. In addition, multivariable extensions using a conicity condition and the concept of maximal cone are adopted to give stability boundaries in interconnections of SIMO linear-MISO sector-bounded memoryless blocks. All the robust stability criteria are illustrated using significant examples to emphasize the practical application of the resulting techniques. 相似文献
8.
In a previous paper, it was proposed to see the deformations of a common pattern as the action of an infinite dimensional group. We show in this paper that this approac h can be applied numerically for pattern matching in image analysis of digital images. Using Lie group ideas, we construct a distance between deformations defined through a metric given the cost of infinitesimal deformations. Then we propose a numerical scheme to solve a variational problem involving this distance and leading to a sub-optimal gradient pattern matching. Its links with fluid models are established. 相似文献
9.
Transport of Relational Structures in Groups of Diffeomorphisms 总被引:1,自引:0,他引:1
Laurent Younes Anqi Qiu Raimond L. Winslow Michael I. Miller 《Journal of Mathematical Imaging and Vision》2008,32(1):41-56
This paper focuses on the issue of translating the relative variation of one shape with respect to another in a template centered
representation. The context is the theory of Diffeomorphic Pattern Matching which provides a representation of the space of
shapes of objects, including images and point sets, as an infinite dimensional Riemannian manifold which is acted upon by
groups of diffeomorphisms. We discuss two main options for achieving our goal; the first one is the parallel translation,
based on the Riemannian metric; the second one, based on the group action, is the coadjoint transport. These methods are illustrated
with 3D experiments.
相似文献
Laurent YounesEmail: |
10.
基于混合遗传算法的m序列波形优化设计 总被引:7,自引:2,他引:5
现代雷达体制多采用大时宽带宽积的m-序列二相编码脉冲压缩波形,解决信号波形优化问题即使信号波形的脉压比在尽量少损失SNR和主瓣宽度的基础上达到极值.对于m-序列,初始寄存器的选取是关键.对于较长的码,传统的优化方法由于运算量过大造成组合爆炸或陷入局部极值而无法找到最优,传统遗传算法也由于初始种群数的规模运算量比较大,将梯度搜索和遗传算法相结合的混合遗传算法很好的解决了这个问题,通过优化m-序列二相码波形的仿真和性能分析验证了该算法的可行性和有效性. 相似文献