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PENG Tao HE Fengling ZUO Wanli 《武汉大学学报:自然科学英文版》2006,11(5):1394-1397
Focused crawlers are important tools to support applications such as specialized Web portals, online searching, and Web search engines. A topic driven crawler chooses the best URLs and relevant pages to pursue during Web crawling. It is difficult to deal with irrelevant pages. This paper presents a novel focused crawler framework. In our focused crawler, we propose a method to overcome some of the limitations of dealing with the irrelevant pages. We also introduce the implementation of our focused crawler and present some important metrics and an evaluation function for ranking pages relevance. The experimental result shows that our crawler can obtain more "important" pages and has a high precision and recall value. 相似文献
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基于可用带宽的QoS多播路由算法 总被引:2,自引:0,他引:2
设计了一种基于时延、时延抖动和包丢失率3个QoS约束下的最大可用带宽多播树求解模型,将可用带宽作为主度量参数来构建多播树。能够针对特定的服务需求对各个QoS度量的重要性进行灵活调整。其算法具有多项式复杂度,并通过仿真证明了算法的有效性。 相似文献
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Introduction Inthe1980sresearchersbelievedthatthebestwayto improvecomputerperformancewasbycreatingfasterand momefficientprocessors.Thisideawaschallengedby parallelprocessingwhichinessencemeanslinkingtogether twoormorecomputerstosolvejointlyacomputational problem.Inearly1990sthetrendwastomoveawayfrom expensiveandspecializedproprietarysupercomputers towardsnetworkofworkstations,producinganew computingplatformcalledCOW.[1]Theemergenceof COWhasbeenfosterednotonlybyrecentadvancesin computerhardw… 相似文献
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Mesial-distal and buccal-lingual dimensions of 1 266 hominoid teeth found in Yuanmou of Yunnan Province during the period
of 1986 and 1988 have been measured. The statistical analyses of the metric data show that the tooth sizes of Yuanmou hominoid
can be divided into big and small two types, and most tooth dimensions display obvious bimodalities in both histograms and
2 dimensional plots. The coefficients of variance (CV) reveal that the CVs of Yuanmou hominoid tooth sizes are within or close
to the CV ranges ofLufengpithecus and extant great apes. The comparisons of tooth sizes and their proportions indicate that Yuanmou hominoids have close affinities
with Lefeng and Kaiyuan hominoids, and have obvious differences with Gorilla, Chimpanzee and Orangutan. The authors believe
that the hominoid fossils found in Yuanmou in the past 10 years represent a single species with highly sexual dimorphism in
morphology and this species may have a close evolutionary relationship with the hominoids found in Kaiyuan and Lufeng. 相似文献
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通过改进FRT算法,得到随机最小序分割算法(random minimum order partition, RMOP)。在度量空间G中,对点列V进行随机排序(设序列为π),随机选取点u∈V后,获得下标Jr(u)=inf{j∈N:d(πj,u)≤r,πj,u∈V},再以点πJr(u)为球心r为半径,对度量空间G进行递归分割,进而形成一棵分层良分割树(hierarchically well separated tree, HST);同时得到E(dT(u,v))≤O(logn)d(u,v)。在RMOP算法与FRT算法具有相同的π时,RMOP算法能保证点u落入特定分割子集B(πJr(u),r)的概率最大。 相似文献
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鄂大伟 《复杂系统与复杂性科学》2005,2(4):77-83
从软件工程的视角对软件复杂性进行了初步研究,讨论了软件复杂性的基本定义,分析了软件复杂性产生的原因及软件度量方法,最后提出了未来适应软件复杂性的几种技术解决方案. 相似文献
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基于离散曲率的二次误差度量网格简化算法 总被引:1,自引:0,他引:1
在医学图像三维重建时产生大量的三角面片,极大地限制了三维重建的速度。提出了一种基于离散曲率的二次误差度量网格简化算法。在代价函数中引入顶点离散曲率,通过将代价函数作为顶点对的权值来控制顶点对合并次序,更好地保留了原模型的细节特征,同时修改模型特征点与特征线的权值,使得简化过程中原模型的特征点与特征线能够较好地保留。经实验对比与分析表明,该算法有效地提高了图像质量且能很好地保持原模型的图形特征。 相似文献
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彝族诗歌的音律,从原文看与汉语诗歌相比有根本的不同,其基本形式是押包括韵母、声母、声调在内的音节。彝文文献长诗的音律,也是押的音节,是对一般诗歌押音节模式的灵活运用。在一个长诗文本中,交替着押不同的音节,且有时为行行押,有时为隔行押,有时为段尾押,有时为句首押,有时为句中押,使作品在音律上呈现出起伏变化的动态美。 相似文献