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91.
以典型多变量非线性系统一球棒系统为研究对象,用微分几何理论中的状态反馈的近似线性化方法设计该非线性系统的控制器.无论小球在棒的什么位置,棒的角度如何,该控制方法都能使小球稳定在棒的中心位置.利用数学工具Mat-lab仿真此过程,给出了Matlab具体实现模块,结果表明状态反馈方法的有效性. 相似文献
92.
空间曲梁非线性动力学方程 总被引:1,自引:3,他引:1
基于有限变形原理,采用微分几何的方法推导了不考虑剪切、转动惯量和翘曲影响的曲梁的二维变形的应力-应变关系.然后利用Hamilton变分原理推导了三维空间曲梁在考虑三个位移自由度和三个转动自由度下的非线性动力学方程.把得到的非线性动力学方程退化为面内圆弧拱的线性动力学方程,并与已有结果进行了对比.非线性动力学方程的建立为曲梁的非线性动力学分析做好了必要的准备. 相似文献
93.
Two algorithms for constructing a Delaunay triangulation 总被引:51,自引:0,他引:51
This paper provides a unified discussion of the Delaunay triangulation. Its geometric properties are reviewed and several applications are discussed. Two algorithms are presented for constructing the triangulation over a planar set ofN points. The first algorithm uses a divide-and-conquer approach. It runs inO(N logN) time, which is asymptotically optimal. The second algorithm is iterative and requiresO(N
2) time in the worst case. However, its average case performance is comparable to that of the first algorithm.This work was supported in part by the National Science Foundation under grant MCS-76-17321 and the Joint Services Electronics Program under contract DAAB-07-72-0259. 相似文献
94.
提出了一种基于线元几何与运动方程的旋转体点云数据特征分离与旋转轴提取算法。该算法将三维空间中的点云数据投影到线元空间中,通过拟合运动方程并分析运动特征参数而计算出旋转轴位置。算法使用基于特征约束的klo-RANSAC(k-local-RANSAC)算法将特征点从自由曲面背景以及噪声中提取和分离,进一步提高了算法的收敛速度与健壮性。实验证明,本算法无需精确估算曲面法矢即能快速地从海量点云数据中迅速地识别与分离具有旋转特征的数据点并提取其旋转轴特征。 相似文献
95.
Sensing coverage and network connectivity are two of the most fundamental problems in wireless sensor networks. Finding an optimal node deployment strategy that would minimize cost, reduce computation and communication overhead, be resilient to node failures, and provide a high degree of coverage with network connectivity is extremely challenging. Coverage and connectivity together can be treated as a measure of quality of service in a sensor network; it tells us how well each point in the region is covered and how accurate is the information gathered by the nodes. Therefore, maximizing coverage as well as maintaining network connectivity using the resource constrained nodes is a non-trivial problem. In this survey article, we present and compare several state-of-the-art algorithms and techniques that aim to address this coverage–connectivity issue. 相似文献
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98.
Adelina-Gabriela Niculescu Dan Eduard Mihaiescu Alexandru Mihai Grumezescu 《International journal of molecular sciences》2022,23(15)
Microfluidics is defined as emerging science and technology based on precisely manipulating fluids through miniaturized devices with micro-scale channels and chambers. Such microfluidic systems can be used for numerous applications, including reactions, separations, or detection of various compounds. Therefore, due to their potential as microreactors, a particular research focus was noted in exploring various microchannel configurations for on-chip chemical syntheses of materials with tailored properties. Given the significant number of studies in the field, this paper aims to review the recently developed microfluidic devices based on their geometry particularities, starting from a brief presentation of nanoparticle synthesis and mixing within microchannels, further moving to a more detailed discussion of different chip configurations with potential use in nanomaterial fabrication. 相似文献
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100.
Consider sets S of hypercubes of side 2 in the discrete n-dimensional torus of side 4 with the property that every possible hypercube of side 2 has a nonempty intersection with some hypercube in S. The problem of minimizing the size of S is studied in two settings, depending on whether intersections between hypercubes in S are allowed or not. If intersections are not allowed, then one is asking for the smallest size of a non-extensible packing S ; this size is denoted by f(n). If intersections are allowed, then the structure S is called a blocking set. The smallest size of a blocking set S is denoted by h(n). By computer-aided techniques, it is shown that f(5)=12, f(6)=16, h(6)=15 and h(7)≤23. Also, non-extensible packings as well as blocking sets of certain small sizes are classified for n≤6. There is a direct connection between these problems and a covering problem originating from the football pools. 相似文献