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基于结构稳定性校准的在线式社区识别
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作者 杨海陆 张健沛 杨静 《自动化学报》 EI CSCD 北大核心 2014年第10期2151-2162,共12页
本文探讨在线社会网络的社区识别问题,重点研究网络演变特性对社区结构产生的影响.首先基于节点的邻域倾向性提出社区稳定性的概念并给出稳定社区的快速识别算法,然后设计了一种基于事件的社区稳定性校准算法以此识别新网络的社区结构.... 本文探讨在线社会网络的社区识别问题,重点研究网络演变特性对社区结构产生的影响.首先基于节点的邻域倾向性提出社区稳定性的概念并给出稳定社区的快速识别算法,然后设计了一种基于事件的社区稳定性校准算法以此识别新网络的社区结构.由于算法的局部搜索策略,该方法无需在新时间片段重复执行,并且可以在无参数条件下识别加权网络中具有任意形状的社区结构.在人工合成网络和真实网络上的实验结果验证了算法的可行性和有效性. 展开更多
关键词 在线社会网络 重叠社区识别 社区稳定性 校准策略
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The Effect of Utilisation on the Floristic Composition of Meadow Communities 被引量:1
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作者 Anna Kryszak Jan Kryszak Agnieszka Strychalska Agnieszka Klarzynska 《Journal of Life Sciences》 2012年第9期1061-1067,共7页
This study presents research results which comprise the following selected communities: Phalaridetum arundinaceae, Alopecuretum pratensis, community with Deschampsia caespitosa, Holcetum lanati, Lolio-Cynosuretum, co... This study presents research results which comprise the following selected communities: Phalaridetum arundinaceae, Alopecuretum pratensis, community with Deschampsia caespitosa, Holcetum lanati, Lolio-Cynosuretum, community Poa pratensis-Festuca rubra. The investigated phytocenoses developed in conditions of lack of utilisation, occasional cutting, occasional alternating meadow-pasture utilisation, pastures with uncut left-overs, 2 cuts and light grazing of the sward by cattle and 2-3 cuts. For the above-mentioned communities the following parameters were assessed: total species number and mean number of species in a phytosociological rel6ves besides Shannon-Wiener diversity index (H'), proportion of synanthropic species, natural valorisation number according to Ogwit and fodder value score (FVS). Regular sward utilisation of plant communities exerts a positive impact not only on the natural values as evidenced by the total and mean number of species in a phytosociological survey and higher biodiversity index (H') but it also impacts the sward fodder value scores of meadows and pastures. The strongest negative influence on the floristic composition of meadow communities and their stability is exerted by sporadic, incorrect utilization as it favours taking over of green areas by grass expansive species and development of communities of low natural and use values (community with Deschampsia caespitosa, Ass. Holcetum lanati and community with Agropyron repens). The strongest impact on the maintenance of meadow and pasture biological stability in the examined region is exerted by their regular, moderate cutting or grazing. 展开更多
关键词 Meadow communities HABITAT UTILISATION floristic diversity natural valorisation
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Impulsive Cluster Synchronization in Community Network with Nonidentical Nodes
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作者 邓丽萍 吴召艳 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第10期525-530,共6页
In this paper,cluster synchronization in community network with nonidentical nodes and impulsive effects is investigated.Community networks with two kinds of topological structure are investigated.Positive weighted ne... In this paper,cluster synchronization in community network with nonidentical nodes and impulsive effects is investigated.Community networks with two kinds of topological structure are investigated.Positive weighted network is considered first and external pinning controllers are designed for achieving cluster synchronization.Cooperative and competitive network under some assumptions is investigated as well and can achieve cluster synchronization with only impulsive controllers.Based on the stability analysis of impulsive differential equation and the Lyapunov stability theory,several simple and useful synchronization criteria are derived.Finally,numerical simulations are provided to verify the effectiveness of the derived results. 展开更多
关键词 cluster synchronization community network impulsive control
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