Peer-to-peer service provisioning in cloud computing environments

This paper aims to advance the management and delivery of services in large, heterogeneous, uncertain, and evolving cloud computing environments. The goal is important because such systems are becoming increasingly popular, yet existing service management methods do not scale well, and nor do they perform well under highly unpredictable conditions. If these problems can be solved, then Information Technology (IT) services can be made to operate in more scalable and reliable manner. In this paper, we present a peer-to-peer approach for managing services in large scale, dynamic, and evolving cloud computing environments. The system components such as virtualized services, computing servers, storage, and databases self-organize themselves using a peer-to-peer networking overlay. Inter-networking system components through peer-to-peer routing and information dissemination structure is essential to avoid the problems of management bottleneck and single point of failure that is predominantly associated with traditional centralized and hierarchical distributed (grids/clouds) system design approaches. We have validated our approach by conducting a set of rigorous performance evaluation study using the Amazon EC2 cloud computing environment. The results prove that managing services based on peer-to-peer routing and information dissemination structure is feasible and offers significant performance benefits as regards to overall system reliability, scalability, and self-management.     

Social network analysis for optimal machining conditions in ultra-precision manufacturing

Ultra-precision machining (UPM) technology is extensively applied to manufacture top quality products with high precision level and complicated geometry. As complicated machining factors affect the surface quality of machined components in UPM, large numbers of experiments for understanding the influences from particular machining factors are needed, leading overestimate or underestimate of significance of machining factors at certain machining conditions and raising of experimental cost. For these reasons, a crucial approach is urged to adapt for providing a fast track to an optimal machining condition. In this study, social network analysis (SNA) is introduced firstly to develop UPM network, which the network shows the relationship between dominant machining factors in UPM. A complicated UPM network containing interdependencies between each machining factor is generated by SNA. The determinations of network metrics in the UPM network support the selection of optimal machining factors under various machining conditions. Furthermore, the constructed UPM network using SNA provides the complete framework of dependencies in UPM for well predicting the machining outcomes when particular machining factors are adjusted in practical situations. The study contributes to offering a detail guideline for constructing machining strategies or experimental plans to efficiently achieve desired machining outcomes.     

Application of computational intelligence techniques in active networks

 Computational intelligence techniques have been successfully used for solving control problems in packet-switching network architectures. The introduction of active networking adds a high degree of flexibility in customizing the network infrastructure and introducing new functionality. Therefore, there is a clear need for investigating both the applicability of computational intelligence techniques in this new networking environment, as well as the provisions of active networking technology that computational intelligence techniques can exploit for improved operation. We report on the characteristics of these technologies, their synergy and on outline recent efforts in the design of a computational intelligence toolkit and its application to routing on a novel active networking environment.     

控制系统网络化及控制系统与信息网络集成技术

控制系统网络化是控制系统发展的必然．本文对比了控制系统网络化发展三个主要 阶段的特点，分析了基于TCP/IP协议的开放嵌入式网络化控制系统的现状．不同控制网络系 统的集成是当前控制系统网络化的主要特点之一，本文阐述了多种控制网络互连与集成的方 法．控制网络与信息网络的集成具有重要理论和现实意义．从网络化发展的角度来研究控制 系统的发展，将更有利于自动控制、计算机网络和通讯技术的融合，为实现控制和管理信息 一体化提供了一条新思路．     

基于P2P的无线mesh网移动性管理研究

无线Mesh网是一种新型的无线组网技术,现有的无线移动管理协议还不能在这一网络结构上直接适用.在典型无线mesh网络分层结构模型上,对现有的几种无线网络移动管理协议进行了比较,并且针对无线mesh网的结构特点提出了一种大型无线mesh网络下的移动性管理方案,采用了基于P2P的分层结构实现网络移动定位信息的自动注册、自动管理和快速查询,同时网络具有较好的负载均衡和抗毁性能.仿真结果表明,与传统的分层移动管理协议相比,该方案可以得到更优化的移动路由.     

一种P2P网络鲁棒访问控制协议

针对基于离散小波变换的视频降噪方法难于实时处理的问题,提出了一种基于提升框架的可实时处理的视频降噪方法。首先,对每帧图像利用提升框架进行多级小波分解,得到尺度系数和小波系数;然后,对不同层次的小波系数采用软阈值收缩方法进行滤波;小波逆变换后,利用时间域滤波方法进一步提高降噪效果。实验结果表明,该方法具有较好的实时性和去噪效果。     

Layer 2 over IP/MPLS

Over the past several years, traditional carriers and Internet service providers (ISPs) have invested billions of dollars deploying high-speed, high-capacity IP networks. This expansion is intended to lay the foundation for a network that could accommodate exponential traffic growth and deliver new revenue-generating services. Traffic from advanced services incorporating elements such as on-demand video, packet voice, wireless communications, and peer-to-peer networking is expected to consume whatever capacity providers can offer while leading to increased opportunities for revenue growth. The advanced services traffic has yet to materialize. An unintentional consequence of this buildout, however, is that ISP networks possess a glut of capacity. At the same time, ISPs are under great pressure to reduce operational and infrastructure costs while attempting to make money and attract customers with new services. One way to achieve both goals is to carry all traffic over a single IP or multiprotocol label-switching (MPLS) network     

一种Twitter社区中社会网络分析方法

选取Twitter中文社区作为研究对象,提出一种社会网络分析方法。从微博客中用户之间的关注关系以及信息传播途径出发,采用社会网络分析方法,对微博客中的社会网络结构进行量化分析,研究其社会网络的密度、中心性、位置和角色。分析结果表明,该方法能避开信息碎片化、负面消息爆炸性传播等难题,可应用于有关国家安全问题的监控。     

基于事务日志的社会网络抽取

社会网络分析(social network analysis, SNA)是数据挖掘领域的一个重要研究方向,社会网络数据的质量和规模对研究十分重要.在当前的社会网络分析研究中,大多数是基于社交网站生成的社会网络,社交网站生成的在线社会网络只是对真实社会网络近似模拟,其现象、结论无法代表真实社会网络;少数基于真实社会网络的研究中,由于数据采集难度较大,往往只能使用规模有限的社会网络,从而降低了分析结果的可信程度.现代软件系统产生大量的事务日志让构建基于真实环境的社会网络成为可能.以高校学生卡管理系统产生的事务日志为例,探索如何从海量事务日志中抽取社会网络.根据事务日志的特征,建立以共现(co-occurrence)特征为基础的网络抽取模型,抽取出所有可能构成这个社会网络的边;定义了一个基于边的权重和Jaccard相关性系数的边存在系数,识别网络中的噪音边,筛选噪音边;最后,通过同班级比率分析和网络拓扑结构分析,对抽取的网络进行验证.实验结果表明,所抽取的网络具有很高的同班级比率,该抽取模型具有较好效果,同时该网络具有小世界网络(small-world)特征和满足无标度(scale-free)度分布,符合常见社会网络特征.     

Supporting Cooperative Software Processes in a Decentralized and Nomadic World

Recent advances in wireless networks enable decentralized cooperative and nomadic work scenarios where mobile users can interact in performing some tasks without being permanently online. Scenarios where connectivity is transient and the network topology may change dynamically are considered. Connectivity among nodes does not require the support offered by a permanent infrastructure but may rely on ad hoc networking facilities. In this paper, a scenario in which a nomadic group of software engineers cooperate in developing an application is investigated. The proposed solution, however, is not software process specific but holds for other cases where shared documents are developed cooperatively by a number of interacting nomadic partners. Support tools for these groups are normally based on a client-server architecture, which appears to be unsuitable in highly dynamic environments. Peer-to-peer solutions, which do not rely on services provided by centralized servers, look more promising. This paper presents a fully decentralized cooperative infrastructure centered around peer-to-peer versioning system (PeerVerSy), a configuration management tool based on a peer-to-peer architecture, which supports cooperative services even when some of the collaborating nodes are offline. Some preliminary experiences gained from its use in a teaching environment are also discussed     

SocialVPN: Enabling wide-area collaboration with integrated social and overlay networks

Trusted collaborative systems require peers to be able to communicate over private, authenticated end-to-end channels. Network-layer approaches such as Virtual Private Networks (VPNs) exist, but require considerable setup and management which hinder the establishment of ad-hoc collaborative environments: trust needs to be established, cryptographic keys need to be exchanged, and private network tunnels need to be created and maintained among end users. In this paper, we propose a novel system architecture which leverages existing social infrastructures to enable ad-hoc VPNs which are self-configuring, self-managing, yet maintain security amongst trusted and untrusted third parties. The key principles of our approach are: (1) self-configuring virtual network overlays enable seamless bi-directional IP-layer connectivity to socially connected parties; (2) online social networking relationships facilitate the establishment of trust relationships among peers; and (3) both centralized and decentralized databases of social network relationships can be securely integrated into existing public-key cryptography (PKI) implementations to authenticate and encrypt end-to-end traffic flows. The main contribution of this paper is a new peer-to-peer overlay architecture that securely and autonomously creates VPN tunnels connecting social peers, where online identities and social networking relationships may be obtained from centralized infrastructures, or managed in a decentralized fashion by the peers themselves.This paper also reports on the design and performance of a prototype implementation that embodies the SocialVPN architecture. The SocialVPN router builds upon IP-over-P2P (IPOP) virtual networks and a PKI-based tunneling infrastructure, which integrates with both centralized and decentralized social networking systems including Facebook, the Drupal open-source content management system, and emailing systems with PGP support. We demonstrate our prototype’s ability to support existing, unmodified TCP/IP applications while transparently dealing with user connectivity behind Network Address Translators (NATs). We also present qualitative and quantitative analyses of functionality and performance based on wide-area network experiments using PlanetLab and Amazon EC2.     

主动网络管理系统模型设计

主动网络是一种新型网络体系结构,它可以为网络协议、网络服务的快速升级和部署提供简单的网络平台。但是传统的网络管理模型不适应主动网络的管理,不能发挥主动网络的分布式计算能力。该文在分析传统网络管理模型的局限性的基础上,提出了主动网络管理模型(ANM),并以网络拓扑发现过程为例对两种网络管理模型进行了比较。     

Digital repository: preservation environment and policy implementation

Distributed digital repositories can be used to address critical issues of long-term digital preservation and disaster management for large data centers. A policy-driven system provides an ideal solution for managing distributed repositories that require high flexibility and high configurability. Recent studies demonstrate that the integrated Rule-Oriented Data System, a peer-to-peer server middleware, provides the requisite dynamic extensibility needed to manage time-varying policies, automate validation of assessment criteria, manage ingestion processes, manage access policies, and manage preservation policies. The policy management can be implemented underneath existing digital library infrastructure such as Fedora.     

一个应用于移动Ad Hoc网络管理的簇生成算法

移动Ad hoc网络(mobile Ad hoc network,简称MANET)作为一种新型移动无线通信网,与其他通信网络相比独有的特性增加了网络管理的难度.目前对MANET网络管理的研究处于起步阶段,一些标准尚未制定,而且像存在单向链路和节点的相对移动性这类问题也在研究中被忽视.为此,提出了一个利用令牌机制与最小节点标识相结合,适用于层次性管理结构的基于图的MANET簇生成算法,以及对MIB(management information base)的建议性改进.算法充分考虑了网络存在的单向链路和节点的相对移动性,提高了网络管理的灵活性和可扩展性,为MANET的网络管理提出了一种新方法.     

新型算力网络架构及其应用案例分析

随着人工智能（AI）算力向网络边缘甚至终端设备扩散,端边云超协同的算力网络成为最佳计算解决方案,而新机遇催生了端边云超计算和网络之间的深度集成。然而,集成系统的完整开发还没有得到很好的解决,包括适应性、灵活性和价值性,因此提出了一种区块链赋能的端边云超算力网络架构。其中,端边云超融合为框架提供基础设施,该设施构成的算力资源池为用户提供安全可靠的算力,网络通过调度资源满足用户需求,而框架内的神经网络和执行平台为AI任务执行提供接口;同时,区块链保证资源交易的可靠性,以激励更多算力贡献者加入平台。本框架为算力网络中的用户提供了适应性,为组网算力资源调度提供了灵活性,为算力供应商提供了价值激励,并利用案例清晰地描述了该新型算力网络架构。     

Enhancing Computational Grids with Peer-to-Peer Technology for Large Scale Service Discovery

Within computational Grids, some services (typically software components, e.g., linear algebra libraries) are made available by some servers to some clients. In spite of the growing popularity of such Grids, the service discovery, although efficient in many cases, does not reach several requirements. Among them, the flexibility of the discovery and its efficiency on wide-area dynamic platforms are two major issues. Therefore, it becomes crucial to propose new tools coping with such platforms. Emerging peer-to-peer technologies provide algorithms allowing the distribution and the retrieval of data items while addressing the dynamicity of the underlying network. Whereas merging peer-to-peer technology and Grid infrastructures has been widely suggested, very few implementations are available. The contribution of this paper is twofold. First, we present the design, the implementation and the experimentation of the first architecture, to our knowledge, extending traditional Network-Enabled Servers (NES) systems with an unstructured peer-to-peer network. This extension allows to dynamically connect distributed agents thus providing to clients an entry point to servers geographically distributed. Our implementation is based on the Diet middleware and the JXTA toolbox and experimentation have been conducted on a high speed network. Then, we study the service discovery in a pure peer-to-peer environment. We describe a new trie-based approach for the peer-to-peer service discovery service, supporting range queries while providing fault-tolerance and taking into account the topology of the underlying network. We validate this approach both by analysis and simulation. This work has been supported in part by the ANR project LEGO (ANR-05-CIGC-11).     

Programmable mobile networks

Existing mobile systems (e.g., mobile IP, mobile ATM and third generation cellular systems) lack the intrinsic architectural flexibility to deal with the complexity of supporting adaptive mobile applications in wireless and mobile environments. We believe that there is a need to develop alternative network architectures from the existing ones to deal with the demands placed on underlying mobile signalling, adaptation management and wireless transport systems in support of new mobile services, e.g. interactive multimedia and web access. In this paper we present the design, implementation and evaluation of mobiware, a middleware technology that enables the introduction of new services in mobile networks. Mobiware provides a toolkit that service providers can utilize to build services that can dynamically exploit the intrinsic scalable properties of mobile multimedia applications in response to time-varying mobile network conditions. Based on an open programmable networking paradigm, mobiware runs on mobile devices, wireless access points and mobile-capable switch/routers providing a set of open programmable interfaces and distributed objects for adaptive mobile networking. Mobiware is software-intensive and is built on CORBA and Java distributed object technologies. The source code for mobiware v1.0 is freely available (comet.columbia.edu/mobiware) for experimentation.     

小型飞行器无线组网系统设计与实现

针对现有小型飞行器组网通信的无线网络标准技术在接入模式、网络延迟和灵活性等方面存在的问题,提出了一种通视条件全空域无线组网的系统架构和方案,完成了相应组网终端的软硬件设计、实现及系统测试验证。方案在网络层采用动态时分多址(TDMA)接入技术,构建低时延的无中心网状网络,使网络节点可动态、快速地接入和退出网络,兼顾了时间敏感数据的实时传输和突发数据的大容量传输;在物理层采用基于频谱感知的自适应跳频通信技术,以保证不受干扰影响的可靠通信,增强了系统的抗干扰和抗截获能力。在组网终端的设计过程中,利用模块化和低功耗处理器集成设计,平衡了SWaP指标,满足了苛刻使用环境条件下的通信距离和数据传输速率等指标需求。系统测试验证表明该组网系统方案可行、性能良好。     

基于SNA的指挥控制关系建模与分析

社会网络分析（Social Network Analysis,SNA）方法是指挥控制关系研究领域新近引入的一种有效的定量分析方法。研究了构建C2组织的指挥控制关系网络模型的基本方法,将组织的实体要素划分为侦察单元、决策单元和执行单元三类;从社会学的角度分析了C2组织中指挥控制权力的“影响”和“支配”两个维度,并重新定义了指挥控制关系;将实体单元和单元之间的指挥控制关系抽象为网络模型的点和边。结合想定示例,具体说明了网络模型的构建方法,并以指挥控制关系的“点度中心性”为例对模型进行了实际的计算和分析。研究表明,基于社会网络分析方法的指挥控制关系建模与分析具有现实意义和实用价值。     

The performance impact of traffic patterns on routing protocols in mobile ad hoc networks

As mobile ad hoc network (MANET) systems research has matured and several testbeds have been built to study MANETs, research has focused on developing new MANET applications such as collaborative games, collaborative computing, messaging systems, distributed security schemes, MANET middleware, peer-to-peer file sharing systems, voting systems, resource management and discovery, vehicular computing and collaborative education systems. The growing set of diverse applications developed for MANETs pose far more complex traffic patterns than the simple one-to-one traffic pattern, and hence the one-to-one traffic pattern widely used in previous protocol studies has become inadequate in reflecting the relative performance of these protocols when deployed to support these emerging applications.As a first step towards effectively supporting newly developed and future diverse MANET applications, this paper studies the performance impact of diverse traffic patterns on routing protocols in MANETs. Specifically, we propose a new communication model that extends the previous communication model to include a more general traffic pattern that varies the number of connections per source node. We study the performance impact of traffic patterns on various routing protocols via detailed simulations of an ad hoc network of 112 mobile nodes. Our simulation results show that many of the conclusions drawn in previous protocol comparison studies no longer hold under the new traffic patterns. These results motivate the need for performance evaluation of ad hoc networks to not only include rich and diverse mobility models as has been done in the past but also include diverse traffic patterns that stress a wide set of protocol design issues.