基于Dijkstra算法的社交网络抽样生成

针对社交网络中随机抽样算法抽样结果不能很好地代表原始网络的问题,设计了一种基于Dijkstra最短路径的抽样算法。首先,利用Dijkstra算法多次抽取社交网络中节点之间的最短路径;然后,对抽取到的路径中边出现的频率进行排序,选择较高频率的边组成抽样的子图。该算法解决了随机抽样算法存在的一些问题,实现了较好的生成抽取社交网络的功能。仿真实验结果表明,与随机抽样方法相比,所提抽样算法能减少抽样误差,更好地反映原始网络。     

复杂网络拓扑可视化方案设计与实现

针对复杂网络拓扑采用传统网络拓扑可视化方式呈现会导致网络结构信息难以观察的问题,文中在提出一种基于节点和边关键性的网络拓扑压缩算法—NECB算法以及改进的FDA算法—FR算法的基础上,利用复杂网络拓扑可视化软件NetworkX设计并实现了一种复杂网络拓扑可视化方案。呈现结果表明NECB算法能在有效压缩网络拓扑规模的同时保存原始网络的主要信息,该方案能有效展现复杂网络拓扑的结构信息,为分析复杂网络提供支持。     

基于社区探测的层次自适应并行布局算法

针对大规模网络高效布局和递进式结构分析的需求,提出基于社区发现的多层级力导向布局算法.首先,该算法采用Louvain算法对网络进行多层级社团结构划分,根据划分结果压缩网络并进行骨架布局,确定网络整体架构;然后,采用自适应的力导向变体算法对各个社团内部的原始节点并行布局,细化社区内部网络结构,并引入补偿力减少社区划分带来的网络结构信息缺失;最后,设计了初始布局算法、改良了振颤模型来减少布局所需的迭代次数.实验结果表明,与现有网络布局算法相比,该算法能够更清晰、高效地展示大规模社交网络数据,满足大规模复杂网络可视化的需要.     

基于局部信息的复杂网络社团结构发现算法

发现网络中的社团结构有助于更好地理解网络结构和分析网络属性。通过定义边的聚类系数和基于局部信息的方法,提出了一种寻找复杂网络中社团结构的算法。该算法首先在网络的剩余节点中寻找度最大的节点,然后利用该节点的局部信息、边的聚类系数和凝聚的思想,得到复杂网络的社团结构。在两个典型网络上的测试结果表明了该方法的可行性。     

一种适用于复杂环境的冗余检测算法

在无线传感器网络中,由于节点能耗的不均衡导致节点感知半径的不同.针对这种复杂环境的应用,提出了一种分布式冗余检测算法,给出了相应的冗余检测准则,并对该准则的合理性进行了理论分析.在保持网络原始覆盖质量的前提下,能够更充分地检测冗余节点.仿真实验表明,复杂环境中节点感知半径相同时,算法激活的工作节点数目少,冗余检测完整;感知半径不同时,算法仍能充分、有效地检测冗余节点,从而节省能量、延长网络生存时间.     

基于改进随机游走的网络表示学习算法

现有的基于Word2vec的网络表示学习（NRL）算法使用随机游走（RW）来生成节点序列,针对随机游走倾向于选择具有较大度的节点,生成的节点序列不能很好地反映网络结构信息,从而影响表示学习性能的问题,提出了基于改进随机游走的网络表示学习算法。首先,使用RLP-MHRW算法生成节点序列,它在生成节点序列时不会偏向大度节点,得到的节点序列能更好地反映网络结构信息;然后,将节点序列投入到Skip-gram模型得到节点表示向量;最后,利用链路预测任务来测度表示学习性能。在4个真实网络数据集上进行了实验。在论文合作网络arXiv ASTRO-PH上与LINE和node2vec算法相比,链路预测的AUC值分别提升了8.9%和3.5%,其他数据集上也均有提升。实验结果表明,RLP-MHRW能有效提高基于Word2vec的网络表示学习算法的性能。     

基于移动Sink节点剩余能量树路由算法

在深入研究了异步可延伸能效(SEAD)算法和MintRoute算法的基础上,提出了剩余能量树路由算法,该算法将网络中的节点分成能量相近的区域,再利用SEAD算法的思想,在每个能量相近的区域中构建以采样节点为根,传递节点作为枝叶的树状网络结构模型,将树最末端的节点作为代理节点,Sink节点移动时,只需要保持同代理节点的通信,便可以保证Sink节点同整个网络连通。运用该路由算法可以很好地解决无线传感器网络中的因某个节点过早死亡而导致网络路由"瓶颈"问题和节点间的信息泛洪问题。采用剩余能量树路由算法,可以使网络能量得到更均衡合理充分的利用,仿真实验结果表明,该算法可以很好地延长网络寿命。     

无线传感器网络分布式拓扑图生成模型

拓扑保留图(Topology Preserving Maps,TPMs)作为实际坐标图的抽象视图,在无线传感器网络的路由、定位和边界节点识别等领域有广阔的应用前景。它可以从虚拟坐标系统中导出网络的拓扑图,且不依赖于任何物理位置信息。然而,在一些具有不规则边界的复杂网络以及使用不充分选择的参考节点来映射网络时,TPMs无法达到理想的效果。为此,设计了一种新的拓扑保留图模型——基于多极值点选择的分布式拓扑图生成算法(Multiple Extreme Node Search-Distributed Topology Preserving Maps,MENS-DTPM),其中包括一种基于极值点选择的参考节点选择方法以及一种基于TPMs的分布式拓扑坐标生成算法。这种模型实现了更有效的参考节点选择,能够更好地反映网络的结构。仿真实验结果表明,MENS-DTPM具有比同类算法更好的性能。     

基于平滑高斯半马尔可夫模型的移动无线传感器网络生成树算法

针对以往移动无线传感器网络研究只是单纯地对移动群体进行分簇而没有充分利用组群移动的内部稳定性的问题,结合组移动模型中节点运动的规律和内聚性原理,采用平滑高斯半马尔可夫移动模型刻画组内单个节点移动特征,构建了一种适合移动网络的稳定生成树算法(GM-base stable spanning tree algorithm, GSST);实验证明,该算法从单个节点运动变化入手,在预测未来节点运动情况,选择稳定的链路构建网络结构方面,提高了移动网络的稳定性;同时,利用树的分层特征,简化移动网络的组网过程,并实现网络重组局部化;该算法有效延长节点存活率,均衡数据传输量。     

基于Hebbian法则的P2P学习网络构建算法

针对远程教育环境中信息量过大,学习者分散、难于组织的问题,提出了一种E-Learning学习网络构建算法.该算法采用P2P的网络结构组织节点之间的通信,利用Hebbian学习法则来修改网络节点之间的信任权值,通过不断调整节点的联系人来实现学习网络的构建.学习网络能够对学习者关于学习资源的查询做出符合学习者学习兴趣的反馈,从而最大限度地满足学习者的需求,提高学习者的学习满意度.实验结果表明,算法相比于传统算法,具有较快的网络建设速度、较高的网络建设质量以及较高的鲁棒性,因而能够更好地适用于大规模的E-Learning学习这种开放的分布式环境.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate