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991.
针对XML数据中的孤立点问题,利用聚类分析思想和XML数据嵌套结构特性所蕴含的元素间的上下文信息,设计了一种在XML半结构数据中检测孤立点的算法.该算法把逻辑相关的结点聚集到相应的子空间中,并基于这些相关子空间计算孤立点兴趣度度量XO度量,以此来识别孤立点数据.实验结果表明,该算法在一定规模的孤立点数据下能够达到较高的识别效率. 相似文献
992.
数独基于规则的逐步枚举算法设计 总被引:1,自引:0,他引:1
给出了数独(Sudoku)的6条性质,并在此基础上提出了6条推理规则,然后结合空格填写的一个一组,两个一组及更多个一组的枚举算法,在枚举中进行推理.使推理和枚举结合起来,对有唯一解的数独问题,其求解速度比回溯法快得多,同时也能完成许多数独软件无法进行推理计算的数独难题.用两个数独难题进行验证,表明该方法十分有效. 相似文献
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997.
粘度是高聚物溶液的重要性质.首先通过实验测得高聚物溶液不同浓度下的粘度数据,其次运用Polymer Plus工程模拟软件建立高聚物溶液的粘度模型和用户自定义模型,最后将所建立的模型通过1个闪蒸罐进行模拟计算的实例中进行验证,结果表明该粘度模型在稀溶液时,误差较小,浓度较高时,误差较大;而用户自定义模型能够估算高聚物溶液的粘度,结果准确可靠.所建立的粘度模型能够准确估算溶液的粘度,为聚合工业节省大量的人力物力,增加经济效益. 相似文献
998.
The matched trend test (MTT), developed using a conditional logistic regression, has been proposed to test for association in matched case-control studies to control the bias of known confounding effects and reduce the potential impact of population stratification. The MTT requires a known genetic model. When the genetic model is unknown, a Monte Carlo robust test, MAX, has been proposed for the analysis of matched case-control studies. The MAX statistic takes the maximum of three MTTs optimal for three common genetic models. We derive the asymptotic power for MTTs and robust tests. In particular, we derive the asymptotic p-value for MAX. Using these analytical results, we conduct simulation studies to compare the performance of MAX and the two-degree-of-freedom Chi-square test for matched case-control studies, where the latter is implemented in most computing software. Our simulation results show that MAX is always asymptotically more powerful than the two-degree-of-freedom Chi-square test under common genetic models. Our results provide guidelines for the analysis of genetic association using matched case-control data. An illustration of our results to a real matched pair case-control etiologic study of sarcoidosis is given. 相似文献
999.
Juyong Zhang Chunlin Wu Jianfei Cai Jianmin Zheng Xue‐cheng Tai 《Computer Graphics Forum》2010,29(2):517-526
This paper considers the problem of interactively finding the cutting contour to extract components from a given mesh. Some existing methods support cuts of arbitrary shape but require careful and tedious input from the user. Others need little user input however they are sensitive to user input and need a postprocessing step to smooth the generated jaggy cutting contours. The popular geometric snake can be used to optimize the cutting contour, but it cannot deal with the topology change. In this paper, we propose a geodesic curvature flow based framework to overcome all these problems. Since in many cases the meaningful cutting contour on a 3D mesh is locally shortest in the sense of some weighted curve length, the geodesic curvature flow is an ideal tool for our problem. It evolves the cutting contour to the nearby local minimum. We should mention that the previous numerical scheme, discretized geodesic curvature flow (dGCF) is too slow and has not been applied to mesh segmentation. With a careful observation to dGCF, we devise here a fast computation scheme called fast geodesic curvature flow (FGCF), which only needs to solve a smaller and easier problem. The initial cutting contour is generated by a variant of random walks algorithm, which is very fast and gives reasonable cutting result with little user input. Experiment results on the benchmark mesh segmentation data set show that our proposed framework is robust to user input and capable of producing good results reflecting geometric features and human shape perception. 相似文献
1000.
We present a new intuitive UI, which we call cross‐boundary brushes, for interactive mesh decomposition. The user roughly draws one or more strokes across a desired cut and our system automatically returns a best cut running through all the strokes. By the different natures of part components (i.e., semantic parts) and patch components (i.e., flatter surface patches) in general models, we design two corresponding brushes: part‐brush and patch‐brush. These two types of brushes share a common user interface, enabling easy switch between them. The part‐brush executes a cut along an isoline of a harmonic field driven by the user‐specified strokes. We show that the inherent smoothness of the harmonic field together with a carefully designed isoline selection scheme lead to segmentation results that are insensitive to noise, pose, tessellation and variation in user's strokes. Our patch‐brush uses a novel facet‐based surface metric that alleviates sensitivity to noise and fine details common in region‐growing algorithms. Extensive experimental results demonstrate that our cutting tools can produce user‐desired segmentations for a wide variety of models even with single strokes. We also show that our tools outperform the state‐of‐art interactive segmentation tools in terms of ease of use and segmentation quality. 相似文献