Predicting temporal centrality in Opportunistic Mobile Social Networks based on social behavior of people

Predicting the centrality of nodes is a significant problem for different applications in Opportunistic Mobile Social Networks (OMSNs). However, when calculating such metrics, current studies focused on analyzing static networks that do not change over time or using aggregated contact information over a period of time. Furthermore, the centrality measured in the past is not verified whether it is useful as a predictor for the future. In this paper, in order to capture the dynamic behavior of people, we focus on predicting nodes’ future centrality (importance) from the temporal perspective using real mobility traces in OMSNs. Three important centrality metrics, namely betweenness, closeness, and degree centrality, are considered. Through real trace-driven simulations, we find that nodes’ future centrality is highly predictable due to natural social behavior of people. Then, based on the observations in the simulation, we design several reasonable prediction methods to predict nodes’ future temporal centrality. Finally, extensive real trace-driven simulations are conducted to evaluate the performance of our proposed methods. The results show that the Recent Weighted Average Method performs best in the MIT Reality trace, and the recent Uniform Average Method performs best in the Infocom 06 trace. Furthermore, we also evaluate the impact of parameters m and w on the performance of the proposed methods and find proper values of different parameters for each proposed method at the same time.     

视频大数据研究综述

科学技术与生产力的发展带来了数据量的高速增长,其中视频图像等多媒体数据占了很大的比重。如何高效处理这些海量数据并从中快速挖掘有价值的信息是当前的研究热点。通常大数据具有四个特点,即数据量大、需要快速响应、数据类型多样和价值密度低。视频大数据同样具有以上特点,但其特殊性在于数据冗余更大,需要进行高效的压缩编码与分析处理。总的来说,视频大数据的研究内容包括了视频数据表示、智能视频分析、视频压缩与传输、视频显示与评价等方面。在发展趋势上,视频数据的表示将向真实感与智能化两个方向发展;智能视频分析技术将会借助深度神经网络获得更准确的识别分类结果;视频压缩技术在提升压缩效率的同时也会探索降低编码复杂度的方法,并通过结合人眼视觉感知特性的编码算法来减少视频大数据的视觉冗余;视频显示设备将伴随着视频数据表示形式的改变而进行相应的升级换代;视频质量的评价准则将由单一的图像质量评价向更加综合全面的用户体验质量评价发展。     

On the Controllability of Nonlocal Second‐Order Impulsive Neutral Stochastic Integro‐Differential Equations with Infinite Delay

In this paper, we investigate the controllability for a class of nonlocal second‐order impulsive neutral stochastic integro‐differential equations with infinite delay in Hilbert spaces. More precisely, a set of sufficient conditions for the controllability results of nonlocal second‐order impulsive neutral stochastic integro‐differential equations with infinite delay are derived by means of the Banach fixed point theorem combined with theories of a strongly continuous cosine family of bounded linear operators. As an application, an example is provided to illustrate the obtained theory.     

An empirical molecular docking study of a di-iron binding protein with iron ions

Various molecular docking software packages are available for modeling interactions between small molecules and proteins.However,there have been few reports of modeling the interactions between metal ions and metalloproteins.In this study,the AutoDock package was employed to example docking into a di-iron binding protein,bacterioferritin.Each binding site of this protein was tested for docking with iron ions.Blind docking experiments showed that all docking conformations converged into two clusters,one for internal iron binding in sites within the metalloprotein and the other for external iron binding on the protein surface.Local docking experiments showed that there were significant differences between two internal iron binding sites.Docking at one site gave a reasonable root-mean-square deviation(RMSD) distribution with relatively low binding energy.Analysis of the binding mode quality for this site revealed that more than half of the docking conformations were categorized as having good binding geometry,while no good conformations were found for the other site.Further investigations indicated that coordinating water molecules contributed to the stability of binding geometries.This study provides an empirical approach towards the study of molecular docking in metalloproteins.     

基于增强现实技术的移动LBS系统的设计与实现

基于位置服务发展迅速,利用增强现实技术开发LBS系统,对人机界面与GIS服务整合具有重要的理论和现实意义。在此基础上,设计一个空间信息服务的构建与发布机制,利用智能终端配备的传感装置,在Android平台手持设备下扩展增强现实功能,融合真实场景和虚拟信息,搭建远程Web服务器完成数据交互,得到整体基于Web服务的LBS原型系统。     

医学图像中组织轮廓提取方法的改进

在医学图像分割技术的研究中,针对提取图像的清晰度和快速性问题,常用轮廓跟踪算法来提取组织轮廓线,花费的时间较长且分割效果不好.为了提高组织轮廓线的提取速度和分割效果,利用医学图像中组织对称性和灰度特征,提出了双向轮廓跟踪算法.根据分割目标确定相应的检测阈值,采用边缘检测,确定边缘起始点,对组织边缘进行双向跟踪.在检测过程中,设置相应的检测矩阵,减少检测次数.算法能同时沿两个不同的方向进行边缘检测,节省了时间.仿真结果表明,改进的轮廓提取方法对有较好的连续性和对称性的组织轮廓线能进行快速准确地提取,可得到清晰的分割结果,缩短轮廓线的生成时间.     

ERDAS LPS与TerraSolid软件相结合快速制作低空数码遥感正射影像图的方法

分析了ERDAS的LPS模块制作DOM的方法及其存在的缺点,介绍了一种结合ERDAS LPS与TerraSolid软件,快速处理超轻型飞机低空数码遥感系统获取的数码航摄影像,制作DOM的技术流程,并通过实验验证了此方法在超轻型飞机低空数码大比例尺航空正射影像图制作中的适应性.     

基于免疫网络的信息安全风险评估模型

风险评估是评价网络信息系统安全的有效措施之一。该文基于免疫网络可动态实时诊断的特性,提出一种新的信息安全风险评估模型,给出模型中各项指标的定量计算方法,以评估整个信息系统的风险值。该模型能够综合考虑评估要素的相互关联,针对风险动态更新,进行实时监控。实验验证了其评估信息系统安全状态的有效性。     

高性能逻辑文件系统设计与实现

服务器端文件系统不仅需要很大的容量,而且要为大量并发访问提供很高的I/O性能。该文提出一种把多个物理文件系统通过软件集成为一个逻辑文件系统的技术,很好地聚合了各个文件系统所在磁盘设备的带宽和容量,综合了不同文件系统在元数据和数据处理性能上的优势。性能测试结果表明,逻辑文件系统技术是一种构造支持高度并发访问的高性能文件系统的有效方法。