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991.
In this paper we consider the following problem of computing a map of geometric minimal cuts (called MGMC problem): Given a graph G=(V,E) and a planar rectilinear embedding of a subgraph H=(V H ,E H ) of G, compute the map of geometric minimal cuts induced by axis-aligned rectangles in the embedding plane. The MGMC problem is motivated by the critical area extraction problem in VLSI designs and finds applications in several other fields. In this paper, we propose a novel approach based on a mix of geometric and graph algorithm techniques for the MGMC problem. Our approach first shows that unlike the classic min-cut problem on graphs, the number of all rectilinear geometric minimal cuts is bounded by a low polynomial, O(n 3). Our algorithm for identifying geometric minimal cuts runs in O(n 3logn(loglogn)3) expected time which can be reduced to O(nlogn(loglogn)3) when the maximum size of the cut is bounded by a constant, where n=|V H |. Once geometric minimal cuts are identified we show that the problem can be reduced to computing the L ∞ Hausdorff Voronoi diagram of axis aligned rectangles. We present the first output-sensitive algorithm to compute this diagram which runs in O((N+K)log2 NloglogN) time and O(Nlog2 N) space, where N is the number of rectangles and K is the complexity of the Hausdorff Voronoi diagram. Our approach settles several open problems regarding the MGMC problem. 相似文献
992.
改性木粉/PVC复合材料的研究进展 总被引:1,自引:0,他引:1
概述了PVC木塑复合材料的发展和背景与性能。简述了木质材料的性质和木粉改性的方法,如物理方法和化学方法。介绍了木塑复合材料的生产流程、成型方法(模压成型、挤出成型、注射成型及其成型设备,讨论了对工艺参数的一些要求。指出目前国内PVC木塑复合材料发展存在的一些问题,并指明了PVC木塑复合材料的应用前景。 相似文献
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Extracting significant features from high-dimension and small sample size biological data is a challenging problem. Recently, Micha? Draminski proposed the Monte Carlo feature selection (MC) algorithm, which was able to search over large feature spaces and achieved better classification accuracies. However in MC the information of feature rank variations is not utilized and the ranks of features are not dynamically updated. Here, we propose a novel feature selection algorithm which integrates the ideas of the professional tennis players ranking, such as seed players and dynamic ranking, into Monte Carlo simulation. Seed players make the feature selection game more competitive and selective. The strategy of dynamic ranking ensures that it is always the current best players to take part in each competition. The proposed algorithm is tested on 8 biological datasets. Results demonstrate that the proposed method is computationally efficient, stable and has favorable performance in classification. 相似文献
996.
以高纯天然石膏为原料,加压水热法制备高品质硫酸钙晶须。采用常规分析方法、XRD和扫描电镜等手段分析和表征石膏原料和硫酸钙晶须产品。结果表明,制备硫酸钙晶须的最优条件为:料浆质量分数为6.0%,转晶剂氯化镁加入量为石膏质量的0.05%,硫酸加入量为水体积的1.0%,反应时间为4.0 h,快速过滤干燥即得硫酸钙晶须产品。分析结果表明:硫酸钙晶须长度最大为280.4 μm,最小为19.59 μm,平均长度为80 μm;硫酸钙晶须直径最大为5.86 μm,最小为0.20 μm,平均直径为2.67 μm;通过统计分析可知,长径比范围为10~80。 相似文献
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Chengjun Xie Jieqing Tan Peng Chen Jie Zhang Lei He 《Machine Vision and Applications》2014,25(7):1859-1876
When objects undergo large pose change, illumination variation or partial occlusion, most existing visual tracking algorithms tend to drift away from targets and even fail to track them. To address the issue, in this paper we propose a multi-scale patch-based appearance model with sparse representation and provide an efficient scheme involving the collaboration between multi-scale patches encoded by sparse coefficients. The key idea of our method is to model the appearance of an object by different scale patches, which are represented by sparse coefficients with different scale dictionaries. The model exploits both partial and spatial information of targets based on multi-scale patches. Afterwards, a similarity score of one candidate target is input into a particle filter framework to estimate the target state sequentially over time in visual tracking. Additionally, to decrease the visual drift caused by frequently updating model, we present a novel two-step object tracking method which exploits both the ground truth information of the target labeled in the first frame and the target obtained online with the multi-scale patch information. Experiments on some publicly available benchmarks of video sequences showed that the similarity involving complementary information can locate targets more accurately and the proposed tracker is more robust and effective than others. 相似文献