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 共查询到10条相似文献,搜索用时 140 毫秒
1.
In this paper, we show that the problem of computing the smallest interval submatrix of a given interval matrix [A] which contains all symmetric positive semi-definite (PSD) matrices of [A], is a linear matrix inequality (LMI) problem, a convex optimization problem over the cone of positive semidefinite matrices, that can be solved in polynomial time. From a constraint viewpoint, this problem corresponds to projecting the global constraint PSD (A) over its domain [A]. Projecting such a global constraint, in a constraint propagation process, makes it possible to avoid the decomposition of the PSD constraint into primitive constraints and thus increases the efficiency and the accuracy of the resolution.D. Henrion acknowledges support of grant No. 102/02/0709 of the Grant Agency of the Czech Republic, and project No. ME 698/2003 of the Ministry of Education of the Czech Republic.  相似文献   

2.
Independent motion detection in 3D scenes   总被引:1,自引:0,他引:1  
This paper presents an algorithmic approach to the problem of detecting independently moving objects in 3D scenes that are viewed under camera motion. There are two fundamental constraints that can be exploited for the problem: 1) two/multiview camera motion constraint (for instance, the epipolar/trilinear constraint) and 2) shape constancy constraint. Previous approaches to the problem either use only partial constraints, or rely on dense correspondences or flow. We employ both the fundamental constraints in an algorithm that does not demand a priori availability of correspondences or flow. Our approach uses the plane-plus-parallax decomposition to enforce the two constraints. It is also demonstrated that for a class of scenes, called sparse 3D scenes in which genuine parallax and independent motions may be confounded, how the plane-plus-parallax decomposition allows progressive introduction, and verification of the fundamental constraints. Results of the algorithm on some difficult sparse 3D scenes are promising.  相似文献   

3.
A Scale Stretch Method Based on ICP for 3D Data Registration   总被引:1,自引:0,他引:1  
In this paper, we are concerned with the registration of two 3D data sets with large-scale stretches and noises. First, by incorporating a scale factor into the standard iterative closest point (ICP) algorithm, we formulate the registration into a constraint optimization problem over a 7D nonlinear space. Then, we apply the singular value decomposition (SVD) approach to iteratively solving such optimization problem. Finally, we establish a new ICP algorithm, named Scale-ICP algorithm, for registration of the data sets with isotropic stretches. In order to achieve global convergence for the proposed algorithm, we propose a way to select the initial registrations. To demonstrate the performance and efficiency of the proposed algorithm, we give several comparative experiments between Scale-ICP algorithm and the standard ICP algorithm.   相似文献   

4.
宋勇春  王茜竹  高正念 《计算机工程》2022,48(2):275-280+290
针对无线系统带宽资源有限、基站负载压力大、传输时延长等问题,提出一种基于非正交多址接入技术的D2D系统吞吐量最大化资源分配算法。在不同用户的服务质量约束条件下,建立D2D系统吞吐量最大化资源分配模型。该模型的优化目标是一个混合整数非线性规划问题,将其解耦为信道匹配与功率分配2个子问题并分别进行处理,利用自适应惩罚函数法处理约束条件并提出一种基于爬山策略的自适应遗传算法以对问题进行求解。仿真结果表明,与GA、AGA算法相比,该算法能够有效提高D2D系统的吞吐量,且收敛性能更好。  相似文献   

5.
In geometric constraint solving, 2D well constrained geometric problems can be abstracted as Laman graphs. If the graph is tree decomposable, the constraint-based geometric problem can be solved by a Decomposition–Recombination planner based solver. In general decomposition and recombination steps can be completed only when steps on which they are dependent have already been completed. This fact naturally defines a hierarchy in the decomposition–recombination steps that traditional tree decomposition representations do not capture explicitly.In this work we introduce h-graphs, a new representation for decompositions of tree decomposable Laman graphs, which captures dependence relations between different tree decomposition steps. We show how h-graphs help in efficiently computing parameter ranges for which solution instances to well constrained, tree decomposable geometric constraint problems with one degree of freedom can actually be constructed.  相似文献   

6.
针对过约束、完整约束和欠约束三维几何约束系统的求解问题,提出了等价性分析方法.该方法基于三维几何约束系统的内在等价性,充分挖掘几何领域知识,依据拆解约束闭环、缩减约束闭环和析出约束闭环等原则,采用等价约束替换来处理几何约束闭环问题,优化几何约束图的结构,实现几何约束系统的优化分解.最后用多个实例验证了该方法的正确性和有...  相似文献   

7.
《Graphical Models》2014,76(5):363-375
In this paper we present a convenient building model synthesis method. It aims at obtaining new user-defined building models through seamless stitching after synthesis of each single building facade. During the optimization process of synthesis of each single building facade, we utilize model structure analysis method to obtain the smallest structural units and the constraint graph among them, transforming complicated three-dimension (3D) synthesis problem into two-dimension (2D) constraint graph synthesis problem. Then we construct a global energy function and minimize it through iterative optimization with expectation maximization algorithm, in order to obtain new objective constraint graph. During stitching process, in order to get complete model synthesis result, we replace objective constraint graph with structural unit to transform synthesis back into 3D space, and achieve automatic stitching between neighboring construction units and neighboring facades by using the connection point sets of structural units in original samples. The experiment results demonstrate our method can generate building models of absolutely different styles quickly and efficiently based on single or multiple samples, while maintaining the continuity and visual integrity of result models well.  相似文献   

8.
This study presents a modified multi-objective evolutionary algorithm based decomposition (MOEA/D) approach to solve the optimal power flow (OPF) problem with multiple and competing objectives. The multi-objective OPF considers the total fuel cost, the emissions, the power losses and the voltage magnitude deviations as the objective functions. In the proposed MOEA/D, a modified Tchebycheff decomposition method is introduced as the decomposition approach in order to obtain uniformly distributed Pareto-Optimal solutions on each objective space. In addition, an efficiency mixed constraint handling mechanism is introduced to enhance the feasibility of the final Pareto solutions obtained. The mechanism employs both repair strategy and penalty function to handle the various complex constraints of the MOOPF problem. Furthermore, a fuzzy membership approach to select the best compromise solution from the obtained Pareto-Optimal solutions is also integrated. The standard IEEE 30-bus test system with seven different cases is considered to verify the performance of the proposed approach. The obtained results are compared with those in the literatures and the comparisons confirm the effectiveness and the performance of the proposed algorithm.  相似文献   

9.
W. Yu  X. Li 《Computer Graphics Forum》2011,30(7):2087-2096
This paper proposes an effective framework to compute the visibility guarding and star decomposition of 3D solid shapes. We propose a progressive integer linear programming algorithm to solve the guarding points that can visibility cover the entire shape; we also develop a constrained region growing scheme seeded on these guarding points to get the star decomposition. We demonstrate this guarding/decomposition framework can benefit graphics tasks such as shape interpolation and shape matching/retrieval.  相似文献   

10.
在 3D 打印、快递物流等领域,需要将形状各异的零件或货物在限定的空间中摆放,称为异形填 充。给出一种摆放方案,以便将尽可能多的多面体放入给定容器;或者一批物体紧密地摆放,使得占用体积最小, 则称为异形填充问题。这是个 NP 问题,很难高效求解。基于此,研究在一个可变维度的三维容器内摆放给定的 一组多面体,使得打包后容器的可变维度最小。并提出一个基于强化学习的算法 AC-HAPE3D,利用启发式算法 HAPE3D 将问题建模为马尔可夫过程,再利用基于策略的强化学习方法 Actor-Critic 进行学习。同时用体素来表 示容器和多面体,从而简化状态信息的表达,并用神经网络表示价值函数和策略函;为了解决状态信息长度以及 动作空间可变的问题,采取遮罩的方法来屏蔽部分输入和输出,并且引入 LSTM 来处理变长的状态信息。在 5 个 不同的数据集进行的实验表明算法能够取得较好的结果。  相似文献   

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