基于DHT发现端到端多条覆盖网路径的方法

为进一步提高端到端数据传输的吞吐率,提出基于DHT发现多条覆盖网路径的方法.一条覆盖网路径由若干跳构成,而数据吞吐率依赖各跳传输性能的瓶颈.为消除瓶颈,根据数据到达结点的吞吐率选择往返延迟时间较小的若干下一跳结点,使得数据不会在该结点拥塞.结点DHT维护着到各下一跳结点的往返延迟时间,基于DHT可发现端-端多条覆盖路径,从而实现并行数据传输.实验结果表明,该方法可找到适合的多条端到端路径,并行传输可取得比单路径传榆更大的吞吐率.     

基于DHT的Chord路由算法的研究与改进

如何有效的确定存储给定数据项的节点在P2P中非常重要。Chord作为结构化P2P的一个典型的比较成功的路由算法一直是人们研究的热点。该文对Chord多节点加入时带来的低效问题进行了分析,并且给出了相应的优化方案。     

一种基于DHT的应用层多播方案

由于应用层多播相对于IP多播的易于部署,得到了国内外学术界的广泛研究。该文从经典的P2P搜索协议Chord入手,构建了基于P2P覆盖网的不定叉树,支持任意源多播,将节点的加入和根的发现结合起来,并对其网络动荡（节点加入与退出）实行制约限制,使网络环境保持基本稳定,达到负载平衡,并预测了本模型发展的方向。     

一种基于DHT的应用层多播方案

由于应用层多播相对于IP多播的易于部署,得到了国内外学术界的广泛研究。该文从经典的P2P搜索协议Chord入手,构建了基于P2P覆盖网的不定叉树,支持任意源多播,将节点的加入和根的发现结合起来,并对其网络动荡(节点加入与退出)实行制约限制,使网络环境保持基本稳定,达到负载平衡,并预测了本模型发展的方向。     

A GIS-based multicriteria spatial decision support system for planning urban infrastructures

The planning of urban infrastructures has important spatial implications. The evaluation of alternative courses of action in this setting requires the explicit consideration of multiple criteria as they have important social, economic, and environmental effects. This paper presents a decision support system aimed at offering the users (e.g., government or municipal agencies) a flexible and user-friendly environment to provide decision aid in urban infrastructure planning. The visualization of available alternatives on maps provides a value-added for decision support processes in urban infrastructure evaluation problems. The development of this system has been motivated by a real world urban case study.     

An RM-ODP enterprise view for spatial data infrastructures

Spatial Data Infrastructures (SDIs) are large, open, distributed and standards-based information systems which intend to facilitate and promote the use of spatial data and spatial services on the Internet. Spatial data describe information tied with locations on Earth, while spatial services allow to manipulate spatial data following a Service Oriented Architecture. This paper proposes to model SDIs as federations of autonomous communities following the enterprise language of the ITU-T and ISO/IEC ‘Reference Model of Open Distributed Processing’ (RM-ODP), and the recently approved ‘Use of UML for ODP Systems Specifications’ (UML4ODP). The enterprise language of the RM-ODP provides a conceptual foundation to address several aspects of SDIs not previously considered from a systems architecture point of view. The use of UML4ODP provides a modeling language to facilitate the exchange of knowledge about SDI, and it is an opportunity to try this recent standard for a class of large and complex systems.     

基于P2P计算的动态多副本开销模型

在多个结点上保持副本是提高P2P或网格计算环境可用性的一个有效途径。不可靠的对等点和网络环境以及用户访问模式的多样性使得难以确定多少个副本能够满足用户高可用性的需求。文章提出了一种最小开销模型来预测和动态控制副本数量。为了隐藏系统中对等点的不可靠性,在考虑多副本的同时通过一种冗余机制预测系统中的副本数量。仿真结果表明,该系统具有更好的可用性和低的副本开销。     

A system design for surveillance systems protecting critical infrastructures

Critical infrastructures are attractive targets for attacks by intruders with different hostile aims. Modern information and sensor technology provides abilities to detect such attacks. The objective of this work is to outline a system design for surveillance systems aimed at protection of critical infrastructures, with the focus on early threat detection at the perimeter of critical infrastructures. The outline of the system design is based on an assessment of stakeholder needs. The needs were identified from interviews with domain experts and system operators. The system design of the surveillance system and the user requirements in terms of capabilities were then determined. The result consists of the system design for surveillance systems, comprising the systems capabilities, the systems structure, and the systems process. The outcome of the work will have an impact on the implementation of the surveillance systems with respect to the sensors utilized, the sensor data algorithms and the fusion techniques.     

一种分层P2P网络中的负载均衡算法

负载失衡是影响P2P系统应用服务性能的关键因素之一。目前,已有的研究集中在基于flat DHT(Distributed Hashing Table)的P2P模型上。分层拓扑结构由于其诸多优点而受到重视。将分层的思想引入虚拟服务器技术中,结合其优势,提出一种层次化的负载均衡算法。仿真实验表明,该算法可以依据节点能力的不同,保证负载在各个节点上公平分布。     

A knowledge-based approach for managing urban infrastructures

This paper presents a knowledge e-based approach dedicated to the efficient management, regulation, interactive and dynamic monitoring of urban infrastructures. This approach identifies the data and related treatments common to several municipal activities and defines the requirements and functionalities of the computer tools developed to improve the delivery and coordination of municipal services to the population. The resulting cooperative system called SIGIU is composed of a set of integrated operating systems (SYDEX) and the global planning and coordination system (SYGEC). The objective is to integrate the set of SYDEX and the SYGEC into a single coherent system for all the SIGIU's users according to their tasks, their roles, and their responsibilities within the municipal administration. SIGIU is provided by different measurement and monitoring instruments installed on some system's elements to be supervised. In this context, the information can be presented in different forms: video, pictures, data and alarms. One of SIGIU's objectives is the real-time management of urban infrastructures' control mechanisms. To carry out this process, the alarm control agent creates a mobile agent associated with the alarm, which is sent to a mobile station and warns an operator. Preliminary implementation results show that SIGIU supports effectively and efficiently the decision making process related to managing urban infrastructures.     

A trust-aware,self-organizing system for large-scale federations of utility computing infrastructures

On-demand computing environments, like Cloud/Grid systems, consist of nodes that individually manage local resources intended to be served to clients. When a client needs some resources, it has the problem of finding the most suitable nodes capable of providing them. In addition, a provider node too may be in need to efficiently locate resources for itself, given the emerging, highly competitive, context of large-scale federations. Indeed, a node competes, with the other federated ones, to obtain the assignment of available tasks. To this end, it may decide to publish a set of resources/ services wider than the one it has currently available. Should such a node be assigned a job for which its actual resources are insufficient, it could end up requiring the collaboration of other nodes.Hence the crucial problem, for nodes and clients alike, is to determine the most promising collaborators. For this purpose, in the competitive and demanding scenarios considered, we advocate taking into account the trustworthiness of nodes in declaring their capabilities, i.e., to help it making an effective selection of possible collaborators, each node should be provided with a trust model for accurately evaluating the trustworthiness of its interlocutors.In this paper, a trust-based approach for large-scale federations Utility Computing infrastructures is proposed. The proposed model is designed to allow any node to find the most suitable collaborators in an efficient way, avoiding exploration of the whole node space. A fully decentralized approach is employed, which allows nodes of a federation to be organized in an overlay network on the basis of suitable criteria. This enables any customer or provider in need of collaborators to determine a suitable set of candidate nodes within which to search.     

Reconfigurable, component-based systems and the role of enterprise engineering concepts

General requirements of next generation enterprise systems are considered and classified. This highlights the potential importance of emerging component-based approaches that facilitate the detailed design of IT systems and their rapid implementation and ongoing development. It also highlights the need for complementary systems engineering approaches that address enterprise engineering on a broad scale, taking into account business and human aspects of large scale projects as well as technical aspects. This characterises the role that current generation enterprise engineering concepts can play in support of the conceptual design of future enterprise engineering systems and in the specification of sets of enterprise components from which large scale, change-capable enterprise systems can be constructed.     

合肥节点网格Portal的设计与实现

网格计算和P2P计算是近年来出现的以最大限度资源共享为目的的新兴技术．而网格Portal则主要致力于增强网格环境的好用性并最终提高资源利用率．本文在制定“采用Portlet框架、面向服务的网格Portal”开发策略的基础上,进行了网格Portal的总体结构设计以及基本原型实现,支持了对网格计算资源和P2P计算资源的协同调度;并在所开发的网格环境中分别部暑了生物和化学应用,通过实验验证了网格Portal的有效性．     

StratoNet：种基于DHT的P2P内容定位系统

提出了一种层次化分布式哈希表系统：StratoNet。该系统按物理网络的远近把节点划分为多个组,使得节点动态加入和退出的影响局限在单个组中,具有良好的稳定性和扩展性,部分查询的性能优越,适合在广域范围部署P2P应用。     

一种融合网格和P2P技术的内容传送方法

网格和P2P是分布式计算系统的两种典型范例,它们各有优缺点.首先简单介绍了网格和P2P的优缺点,阐述了实现两种技术优势互补的可能性,并在此基础上,针对现有的内容传送方法存在的问题,提出了一种在网格环境下融合P2P技术的加快内容传送的方法.     

面向P2P的动态资源模型

为了有效地描述移动计算环境下P2P的动态资源情形,提出了一种面向P2P的动态资源模型——PODRM模型。该模型首先根据P2P模式下的资源特性构造出P2P的网络资源空间,并抽取角色约束及操作约束,从而实现对P2P资源的静态描述。然后,对CPN进行了资源语义扩充,采用扩充了的CPN——E—CPN来刻画资源的动态特性。进而在此基础上构造TPODRM模型。最后给出了该模型的仿真验证。结果表明,该模型能够合理地描述了移动计算环境下P2P的动态资源情形,为动态资源的有效使用及受限资源问题的解决提供了一种有力的理论依据。     

基于PSO-BP集成的国内外企业信用风险评估

为了提高企业信用风险评估准确率,提出了基于PSO-BP集成的企业信用风险评估模型.使用Bagging抽样技术获得足够多不同的训练数据集,用不同的训练集子集训练得到不同的PSO-BP组合成员分类器,最后通过多数投票准则整合不同组合成员分类器的分类结果.分别在包含了国内外公司的详细数据的数据集上证明了模型的有效性.     

网格资源发现模型的研究

提出了一种基于WSRF的网格资源发现模型,该模型采用三层架构以及集中式与分布式相结合的资源组织结构,将网格资源发现中的关键功能包装为有状态的Web服务.同时介绍了在该模型中资源加入与离开算法和资源查询算法.该模型结合WEB服务技术、P2P技术与网格资源管理技术的优点,并经试验测试分析与实际项目检验证明该模型能够适应大规模异构环境下的网格资源发现要求.     

Workflow-based semantics for peer-to-peer specifications

In this paper we introduce SMoL, a simplified BPEL-like language for specifying peer and service behaviour in P2P systems. We then define a transformational semantics of SMoL in terms of Yet Another Workflow Language (YAWL) workflows, which enables the simulation (e.g., testing possible execution scenarios) and analysis (e.g., verifying reachability or lock freedom) of the behaviour of P2P peers and services.     

P2P技术在网格文件管理中的应用

目前把网格分为两类:计算网格和数据网格。计算网格目标在于通过大量计算节点的协作来减少应用程序的执行时间。数据网格提供解决大量数据管理的问题的方法。目前网格文件传输软件例如Grid FTP使用Client/Server结构,在性能和结构上存在问题。将网格和P2P结合起来,提出一种新的非集中式的、高效的数据网格文件管理协议。