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提出一种基于抽样估计的能量异构无线传感器网络分簇算法.采取对网络中节点抽样的办法估计出网络中的平均剩余能量,节点根据剩余能量与网络平均能量的比例来进行簇首竞争,使簇首选择更加合理.仿真实验表明:该算法可以更好地实现负载均衡,延长的网络生存时间. 相似文献
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无线传感器网络中传感器节点能量有限,为了提高能量利用率,针对现有算法随机选择簇首、簇结构不合理等缺陷提出了一种新的能量有效的分簇路由算法EERA.EERA采用新的簇首选举、成簇,以及构建簇间路由算法,基于节点剩余能量与节点的相对位置选择簇首、成簇,使剩余能量较多的节点优先成为簇首并且各簇首能较均匀的分布在网络区域内;构建簇间路由时将最小跳数路由算法与改进的MTE算法结合起来,在簇间形成最小跳数、最小能耗路径.仿真结果表明,EERA算法可以均衡全网能量消耗,延长网络的生命周期. 相似文献
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无线传感器网络(WSN,Wireless Sensor Network)中,如何减少节点的能耗一直是簇头选择机制的研究目标。现提出了一种基于历史能耗信息选择机制的簇头选择算法(CHCM,Cluster Head Choosing Mechanism),该算法通过节点历史能耗信息和节点分布密度参数预测簇头能耗速度,并将该预测方法融入簇头选取过程当中,使网络生命期延长。最后利用CHCM对LEACH路由协议进行改进,得到CHCM+LEACH路由协议。仿真结果表明CHCM+LEACH在网络生命期和网络总剩余能量上分别比LEACH算法分别提高了27%和14%。 相似文献
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一种半集中式低能耗自适应无线传感器网络成簇算法 总被引:1,自引:0,他引:1
基于对LEACH等算法的研究,提出一种半集中式,综合利用节点位置信息与剩余能量的无线传感器网络分簇及簇头选举算法。利用节点位置信息,在簇头选举阶段和传感数据传输阶段使用不同的拓扑划分,在尽可能选取剩余能量较高的节点作为簇头的前提下,能够既保证簇均匀分布,又尽量做到簇头在簇内处于相对中心位置,并且避免了成簇阶段的碰撞。仿真结果表明,该算法有效延长了网络生存周期,收集了更多的传感数据,并且适合大范围覆盖的传感器网络。 相似文献
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文本聚类技术在文本挖掘和信息检索系统中发挥着重要的作用。目前,文本聚类方法大多数采用基于关键词集的经典向量模型来表征文本,这种方式忽略了词与词之间的语义关系,存在词频维数过高,聚类算法计算复杂度高等问题。为了解决这些问题,提出一种基于主题概念聚类的中文文本聚类方法,该方法利用HowNet提取文本的主题概念,然后使用Chameleon算法将主题概念聚类,再依据主题概念的聚类结果完成对文本的聚类。该方法用概念代替单个词条表示文本,减少文本特征之间的依赖关系,有效地降低了文本聚类的时间复杂度。 相似文献
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Clustering by compression 总被引:13,自引:0,他引:13
Cilibrasi R. Vitanyi P.M.B. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2005,51(4):1523-1545
We present a new method for clustering based on compression. The method does not use subject-specific features or background knowledge, and works as follows: First, we determine a parameter-free, universal, similarity distance, the normalized compression distance or NCD, computed from the lengths of compressed data files (singly and in pairwise concatenation). Second, we apply a hierarchical clustering method. The NCD is not restricted to a specific application area, and works across application area boundaries. A theoretical precursor, the normalized information distance, co-developed by one of the authors, is provably optimal. However, the optimality comes at the price of using the noncomputable notion of Kolmogorov complexity. We propose axioms to capture the real-world setting, and show that the NCD approximates optimality. To extract a hierarchy of clusters from the distance matrix, we determine a dendrogram (ternary tree) by a new quartet method and a fast heuristic to implement it. The method is implemented and available as public software, and is robust under choice of different compressors. To substantiate our claims of universality and robustness, we report evidence of successful application in areas as diverse as genomics, virology, languages, literature, music, handwritten digits, astronomy, and combinations of objects from completely different domains, using statistical, dictionary, and block sorting compressors. In genomics, we presented new evidence for major questions in Mammalian evolution, based on whole-mitochondrial genomic analysis: the Eutherian orders and the Marsupionta hypothesis against the Theria hypothesis. 相似文献
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JIANG Wei QU Jiao LI Benxi 《现代电子技术》2007,30(2):152-154
With the development of Support Vector Machine (SVM),the "kernel method" has been studied in a general way.In this paper,we present a novel Kernel-based Maximum Entropy Clustering algorithm (KMEC).By using mercer kernel functions,the proposed algorithm is firstly map the data from their original space to high dimensional space where the data are expected to be more separable,then perform MEC clustering in the feature space.The experimental results show that the proposed method has better performance in the non-hyperspherical and complex data structure. 相似文献
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提出一种适用于大型数据集的分布式聚类算法。该算法以传统的K-means算法为基础进行合理的改进,使之更适用于分布式环境,并从算法的复杂度分析,将该算法与传统的集中式K-means算法及其他分布式算法进行比较。实验表明,该算法在保持了集中式K-means算法所有必要特性的同时,提高了数据处理速度。 相似文献
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针对K—Means图像聚类分割算法需要预先知道图像分割数,且对初始聚类中心较为敏感等问题,提出了一种基于SOFM(自组织特征映射网络)的图像聚类分割算法。该算法结合SOFM聚类及合并聚类分析,能够自动确定分割块数并得到有效的K-Means初始聚类中心。实验结果表明该算法具有运行效率高、分割效果好等优点,在实际应用中是可行的。 相似文献
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We presented a novel framework for automatic behavior clustering and unsupervised anomaly detection in a large video set. The framework consisted of the following key components: 1) Drawing from natural language processing, we introduced a compact and effective behavior representation method as a stochastic sequence of spatiotemporal events, where we analyzed the global structural information of behaviors using their local action statistics. 2) The natural grouping of behavior patterns was discovered through a novel clustering algorithm. 3) A run-time accumulative anomaly measure was introduced to detect abnormal behavior, whereas normal behavior patterns were recognized when sufficient visual evidence had become available based on an online Likelihood Ratio Test (LRT) method. This ensured robust and reliable anomaly detection and normal behavior recognition at the shortest possible time. Experimental results demonstrated the effectiveness and robustness of our approach using noisy and sparse data sets collected from a real surveillance scenario. 相似文献