在社交网络中,通过追踪极少数的强影响力用户,可以实现宏观管控信息的传播过程,而用户影响力是一种无法预判的后验信息,仅能依靠有关特征来确定。因此,提出了一种融入结构度中心性的社交网络用户影响力评估(Structural-Degree-Centralit...在社交网络中,通过追踪极少数的强影响力用户,可以实现宏观管控信息的传播过程,而用户影响力是一种无法预判的后验信息,仅能依靠有关特征来确定。因此,提出了一种融入结构度中心性的社交网络用户影响力评估(Structural-Degree-Centrality User Influence Rank,SDRank)算法来识别强影响力用户。该算法基于PageRank算法,引入了结构度中心性,结合了加入时间与平均转发数的调节因子,进而计算出用户的影响力值。相较于其他的现有算法,SDRank算法仅从用户本身的行为角度出发,不需要诸如个人标签、粉丝等存在伪造风险与缺省可能的具体信息,也不必挖掘传播内容的潜在信息,适用性更广泛。以微博用户的级联转发数据集作为实验对象,对被转发数排名Top-K用户的平均转发数等相关结果进行了可视化分析,探讨了用户转发行为在社交网络信息传播中的作用。在实验过程中,所提算法与PageRank,TrustRank算法相比,准确率、召回率和F1-measure值都有了一定的提高,验证了SDRank算法的有效性。展开更多
Transmission energy spectra of 530 keV H^(+) ion penetrating 140μm thick seed coat of maize and fruit peel of grape with thickness of 100μm were measured.The result indicates that these thick biological targets,as s...Transmission energy spectra of 530 keV H^(+) ion penetrating 140μm thick seed coat of maize and fruit peel of grape with thickness of 100μm were measured.The result indicates that these thick biological targets,as seen by the penetrating ions,are inhomogeneous,and there are open“channel like”paths along which the incidentions can transmit the targets easily.While most of the incident ions are stopped in the targets,some of the transmitting ions only lose a small fraction of their initial incident energy.The transmission energy spectra show a pure electronic stopping feature.Transmission electron microscope(TEM)micrographes taken from the samples of seed coat of maize and fruit peel of tomato with thickness of 60μm indicate that 150keV electron beam from the TEM can penetrate the thick samples to give very good images with clear contrasts.展开更多
文摘在社交网络中,通过追踪极少数的强影响力用户,可以实现宏观管控信息的传播过程,而用户影响力是一种无法预判的后验信息,仅能依靠有关特征来确定。因此,提出了一种融入结构度中心性的社交网络用户影响力评估(Structural-Degree-Centrality User Influence Rank,SDRank)算法来识别强影响力用户。该算法基于PageRank算法,引入了结构度中心性,结合了加入时间与平均转发数的调节因子,进而计算出用户的影响力值。相较于其他的现有算法,SDRank算法仅从用户本身的行为角度出发,不需要诸如个人标签、粉丝等存在伪造风险与缺省可能的具体信息,也不必挖掘传播内容的潜在信息,适用性更广泛。以微博用户的级联转发数据集作为实验对象,对被转发数排名Top-K用户的平均转发数等相关结果进行了可视化分析,探讨了用户转发行为在社交网络信息传播中的作用。在实验过程中,所提算法与PageRank,TrustRank算法相比,准确率、召回率和F1-measure值都有了一定的提高,验证了SDRank算法的有效性。
基金Supported by the National Natural Science Foundation of China under Grant No.19890300in part by the Foundation for Ph.D.Education Programs from the National Education Commission of China under Grant No.96042208.
文摘Transmission energy spectra of 530 keV H^(+) ion penetrating 140μm thick seed coat of maize and fruit peel of grape with thickness of 100μm were measured.The result indicates that these thick biological targets,as seen by the penetrating ions,are inhomogeneous,and there are open“channel like”paths along which the incidentions can transmit the targets easily.While most of the incident ions are stopped in the targets,some of the transmitting ions only lose a small fraction of their initial incident energy.The transmission energy spectra show a pure electronic stopping feature.Transmission electron microscope(TEM)micrographes taken from the samples of seed coat of maize and fruit peel of tomato with thickness of 60μm indicate that 150keV electron beam from the TEM can penetrate the thick samples to give very good images with clear contrasts.
