Application of SmartBox end-device for medical care using JXTA-Overlay P2P system

During last decade more and more old people live alone and the number of old people that need medical care is increased. The lack of doctors and the increase of the medical cost is becoming a big problem. Therefore, IT-based information systems should be implemented to help solve this problem. In this paper, we present the experimental results and evaluation of the SmartBox stimulation device for medical applications using a P2P system which is based on JXTA-Overlay. The SmartBox is integrated with our P2P system as a useful tool for monitoring and controlling patients activities. We found by experimental results that by SmartBox we can check the patient’s situation. We carried out experiments with a patient in the bed and changed the temperature of the room. From the experimental results, we conclude that the use of SmartBox is an effective way for medical applications.     

P2P data replication and trustworthiness for a JXTA-Overlay P2P system using fuzzy logic

P2P systems are very important for future distributed systems and applications. In such systems, the computational burden of the system can be distributed to peer nodes of the system. Therefore, in decentralized systems users become themselves actors by sharing, contributing and controlling the resources of the system. This characteristic makes P2P systems very interesting for the development of decentralized applications. Data replication techniques are commonplace in P2P systems. Data replication means storing copies of the same data at multiple peers thus improving availability and scalability. The trustworthiness of peers also is very important for safe communication in P2P system. The trustworthiness of a peer can be evaluated based on the reputation and actual behaviour of peers to provide services to other peers. In this paper, we propose two fuzzy-based systems for data replication and peer trustworthiness for JXTA-Overlay P2P platform. The simulation results have shown that in the first system, replication factor increases proportionally with increase of number of documents per peer, replication percentage and scale of replication per peer parameters and the second system can be used successfully to select the most reliable peer candidate to execute the tasks.     

Evaluation of P2P multimedia clustering techniques in JXTA-Overlay

Efficient file searching is an essential feature in P2P systems. While many current approaches use brute force techniques to search files by meta information (file names, extensions or user-provided tags), the interest is in implementing techniques that allow content-based search in P2P systems. Recently, clustering techniques have been used for searching text documents to increase the efficiency of document discovery and retrieval. Integrating such techniques into P2P systems is important to enhance searching in P2P file sharing systems. While some effort has been taken for content-based searching for text documents in P2P systems, there has been few research work for applying these techniques to multimedia content in P2P systems. In this paper, we introduce two P2P content-based clustering techniques for multimedia documents. These techniques are an adaptation of the existing Class-based Semantic Search algorithm for text documents. The proposed algorithms have been integrated into a JXTA-based Overlay P2P platform, and evaluation results are provided. The JXTA-Overlay together with the considered clustering techniques is thus very useful for developing P2P multimedia applications requiring efficient searching of multimedia contents in peer nodes.     

A groupware system for virtual product innovation management

We are experiencing a radical shift in the way organizations are designed, structured, and organized. New organizational forms such as virtual strategic partnerships and networks are replacing traditional bureaucratic, hierarchical organizations. This is particularly evident in the area of product innovation, where organizations are adopting new approaches or ways of working in order to compete. Product innovation management is a complex process because of the range of technical issues that must be addressed and the variety of competencies that must be employed over the life of the development effort. Such initiatives require a substantial investment in terms of resources such as time, money, and effort, all of which are limited. This article focuses on product innovation management in a distributed or virtual environment. It reports on a qualitative case study targeted at product managers. The challenges are identified and discussed. From this analysis, a Web‐enabled groupware system is presented. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 499–510, 2007.     

P-Grid:一种高效的自组织P2P系统

P2P（peer to peer）技术在分布计算时代发挥着越来越重要的作用,但在数据管理方面,P2P的应用表现出较大的局限性。作为一种快速高效的P2P信息系统P-Grid,它能够极大地减少其它P2P系统所需要的网络带宽。P-Grid系统的构造和维护严格依照本地交互的随机算法,即使在不可靠的节点也能提供可靠的访问,并且能够较好地衡量存取和通信代价。     

UML在P2P文件下载软件开发中的应用

P2P作为一种基于互联网环境的新的应用型技术，已经得到越来越多的关注，也应用在一些产品中当中。UML作为一个通用的可视化建模语言，在协议和应用方面也不断在完善。文中试以开发一个集中目录式P2P文件下载软件为背景，使用UML进行需求分析，设计和构造，将P2P的技术应用用UML的元素去描述。对整个系统进行用例分析，建立领域模型。针对其中的文件传输的用例做细化，建立设计模型和实施模型，并在设计模型中使用设计模式中的一些方法，例如GRASP等，进行详细的阐述     

基于P2P的数据库管理系统研究*

传统的大型数据库系统是典型的C/S结构,系统中有一个中心服务器,上面运行一个大型数据库系统,其他节点通过服务器访问数据库系统。但这种C/S结构容易在服务器处产生系统瓶颈。为了解决这个问题,将P2P的观念引入数据库系统,建立了一种C/S与P2P相结合的新系统。在该系统中,服务器和客户端是C/S模式,同时所有的客户端组成一个P2P系统。为了提高系统效率又将这个P2P系统根据节点访问的数据表的不同划分为多个小的P2P网络。通过此方式客户端之间实现了数据缓存的共享,从而减少了对服务器访问的频率,减轻了服务器的负担     

A locality-aware resource management scheme for the hierarchical P2P system

In distributed, ubiquitous computing environments, peer-to-peer (p2p) systems have been studied. Distributed hash table (DHT)-based p2p systems can improve load-balancing even though locality utilization and user mobility are not guaranteed. We propose a mobile locality-based hierarchical p2p overlay network (MLH-Net) to address locality problems without any other services. MLH-Net utilizes mobility features in a mobile environment. MLH-Net is constructed as two layers, an upper layer formed with super-nodes and a lower layer formed with normal-nodes. Because super-nodes can share advertisements, we can guarantee physical locality utilization between a requestor and a target during any discovery process. The simulation results demonstrate that the proposed scheme can reduce the discovery routing distance by 21 %, and 45 % compared with JXTA depending on the given number of max-hop.     

Architecture for the next generation system management tools

To get more results or greater accuracy, computational scientists execute their applications on distributed computing platforms such as clusters, grids, and clouds. These platforms are different in terms of hardware and software resources as well as locality: some span across multiple sites and multiple administrative domains, whereas others are limited to a single site/domain. As a consequence, in order to scale their applications up, the scientists have to manage technical details for each target platform. From our point of view, this complexity should be hidden from the scientists, who, in most cases, would prefer to focus on their research rather than spending time dealing with platform configuration concerns.In this article, we advocate for a system management framework that aims to automatically set up the whole run-time environment according to the applications’ needs. The main difference with regards to usual approaches is that they generally only focus on the software layer whereas we address both the hardware and the software expectations through a unique system. For each application, scientists describe their requirements through the definition of a virtual platform (VP) and a virtual system environment (VSE). Relying on the VP/VSE definitions, the framework is in charge of (i) the configuration of the physical infrastructure to satisfy the VP requirements, (ii) the set-up of the VP, and (iii) the customization of the execution environment (VSE) upon the former VP. We propose a new formalism that the system can rely upon to successfully perform each of these three steps without burdening the user with the specifics of the configuration for the physical resources, and system management tools. This formalism leverages Goldberg’s theory for recursive virtual machines (Goldberg, 1973 [6]) by introducing new concepts based on system virtualization (identity, partitioning, aggregation) and emulation (simple, abstraction). This enables the definition of complex VP/VSE configurations without making assumptions about the hardware and the software resources. For each requirement, the system executes the corresponding operation with the appropriate management tool.As a proof of concept, we implemented a first prototype that currently interacts with several system management tools (e.g., OSCAR, the Grid’5000 toolkit, and XtreemOS) and that can be easily extended to integrate new resource brokers or cloud systems such as Nimbus, OpenNebula, or Eucalyptus, for instance.     

Efficient triangulation for P2P networked virtual environments

Peer-to-peer (P2P) architectures have recently become a popular design choice for building scalable Networked Virtual Environments (NVEs). In P2P-based NVEs, system and data management is distributed among all participating users. Towards this end, a Delaunay Triangulation can be used to provide connectivity between the different NVE users depending on their positions in the virtual world. However, a Delaunay Triangulation clearly suffers from high maintenance cost as it is subject to high connection change rate due to continuous users’ movement. In this paper, we propose a new triangulation algorithm that provides network connectivity to support P2P NVEs while dramatically decreasing maintenance overhead by reducing the number of connection changes due to users’ insertion and movement. Performance evaluations show that our solution drastically reduces overlay maintenance cost in highly dynamic NVEs. More importantly, and beyond its quantitative advantages, this work questions the well accepted Delaunay Triangulation as a reference means for providing connectivity in NVEs, and paves the way for more research towards more practical alternatives for NVE applications.     

RFID-based sensing system for context information management using P2P network architecture

An RFID-based sensing system using a P2P network can play an important role in a ubiquitous environment. We developed a network capable of managing its own computing and network resources by combining computing devices with a wide variety of sensors. Context awareness is required to deliver the functionality of the sensing network described in this paper. We designed an RFID-based sensing system that receives contextual information about the user via a P2P network. The proposed system includes the basic RFID equipment needed to use and test an RFID system, which consists of a reader, 30 sample tags, and a sample middleware application for reading, writing, and testing RFID tags. It is able to recognize users entering and leaving a location, as well as determine the distance of a user from itself. It can also recognize the condition of the sensor installation. We designed, implemented, and analyzed a system that provides practical services with real-world educational applications. There were statistically significant differences between the control and test groups for user satisfaction, content learned, learning content composition, and user interface.     

基于非结构化P2P的工作流管理系统

由于突出的灵活性,对流程复杂度较小,节点分散的业务流程的快速适应能力等,建立P2P的工作流引擎成为工作流研发的一个热点方向.P2P环境下构建工作流系统必须解决好节点和工作流参与者的关系等一系列关键问题.给出一套完整的P2P工作流管理系统实现方案,在结合实际工程经验的基础上,分析了每个节点的行为特性,同时根据几种不同的流程运转方式提出了两处XPDL的扩展和3种不同的流程执行的算法,以使XPDL满足P2P环境的要求,并加快流程运转的速度.     

Ex-W-Pert system: A Web-based distributed expert system for groupware design

The World Wide Web (Web) allows people at remotely located sites to communicate and share their ideas using a common communication protocol. A common use of the Web system is running a client application, using a browsing tool, by pointing to a local or proxy server to browse data written in the hypertext format that contains anchors that address other URLs. In this paper a new application of the Web system for sharing knowledge-based systems and groupware development activities is introduced. An architecture for a Web-based Distributed Expert System (Ex-W-Pert System) is proposed and an implementation of the proposed architecture in groupware design is demonstrated. The resources and knowledge bases are distributed and can be accessed through the internet.     

一种面向大规模P2P系统的快速搜索算法

提出一种面向大规模P2P系统的概率搜索小组(probabilistic search team,简称PST)算法.各节点首先发布本节点的资源共享信息,并基于分布式丢弃Bloom Filter技术(distributed discarding bloom filter,简称DDBF)对从其他节点收到的信息进行保存和转发PST算法把RW算法中漫步者的概念扩充为搜索小组通过聚合各小组在搜索过程中获得的资源信息,PST算法实现了多个小组之间相互协同的并行搜索.分析模拟结果表明,PST算法在保持低定位开销的同时取得了较好的定位性能.     

Efficient data-forwarding method in delay-tolerant P2P networking for IoT services

These days Internet of Things (IoT), which consists of smart objects such as sensor nodes is the most important technology for providing intelligent services. In the IoT ecosystem, wireless sensor networks deliver collected information from IoT devices to a server via sink nodes, and IoT services are provided by peer-to-peer (P2P) networking between the server and the IoT devices. Particularly, IoT applications with wide service area requires the mobile sink nodes to cover the service area. To employ mobile sink nodes, the network adopts delay-tolerant capability by which delay-tolerant nodes try to transmit data when they connect to the mobile sink node in the application service field. However, if the connection status between a IoT device and a mobile sink node is not good, the efficiency of data forwarding will be decreased. In addition, retransmission in bad connection cause high energy consumption for data transmission. Therefore, data forwarding in the delay-tolerant based services needs to take the connection status into account. The proposed method predicts the connection status using naïve Bayesian classifier and determines whether the delay tolerant node transmits data to the mobile sink node or not. Furthermore, the efficiency of the proposed method was validated through extensive computer simulations.     

Efficient semantic-based content search in P2P network

Most existing peer-to-peer (P2P) systems support only title-based searches and are limited in functionality when compared to today's search engines. We present the design of a distributed P2P information sharing system that supports semantic-based content searches of relevant documents. First, we propose a general and extensible framework for searching similar documents in P2P network. The framework is based on the novel concept of hierarchical summary structure. Second, based on the framework, we develop our efficient document searching system by effectively summarizing and maintaining all documents within the network with different granularity. Finally, an experimental study is conducted on a real P2P prototype, and a large-scale network is further simulated. The results show the effectiveness, efficiency, and scalability of the proposed system.     

LICRA: A replicated-data management algorithm for distributed synchronous groupware applications

Replicated data consistency is a key issue in the design of distributed real time groupware applications. In this paper, we propose a new protocol to cope with this problem. The proposed algorithm guarantees an optimal response time while ensuring data consistency at system quiescence. The originality of our proposition relies on the fact that neither locks nor clocks nor global information are required to establish data consistency. Instead, direct dependency relations between generated operations as well as operation transformation mechanism are used. The coupling of the above two mentioned mechanisms is shown to realize a good trade-off between the different requirements of groupware applications. Advantages of our approach are illustrated by comparing the algorithm to two well known optimistic concurrency control protocols for groupware applications: dOPT and ORESTE.     

Efficient, proximity-aware load balancing for DHT-based P2P systems

Many solutions have been proposed to tackle the load balancing issue in DHT-based P2P systems. However, all these solutions either ignore the heterogeneity nature of the system, or reassign loads among nodes without considering proximity relationships, or both. In this paper, we present an efficient, proximity-aware load balancing scheme by using the concept of virtual servers. To the best of our knowledge, this is the first work to use proximity information in load balancing. In particular, our main contributions are: 1) relying on a self-organized, fully distributed k-ary tree structure constructed on top of a DHT, load balance is achieved by aligning those two skews in load distribution and node capacity inherent in P2P systems - that is, have higher capacity nodes carry more loads; 2) proximity information is used to guide virtual server reassignments such that virtual servers are reassigned and transferred between physically close heavily loaded nodes and lightly loaded nodes, thereby minimizing the load movement cost and allowing load balancing to perform efficiently; and 3) our simulations show that our proximity-aware load balancing scheme reduces the load movement cost by 11-65 percent for all the combinations of two representative network topologies, two node capacity profiles, and two load distributions of virtual servers. Moreover, we achieve virtual server reassignments in O(log N) time.     

Interaction styles in tools for developing virtual environments

This article discusses and compares interaction styles in development tools for virtual environments (VE). The comparison relies on a qualitative empirical study of two development processes where a command language and a direct manipulation based tool were used to develop the same virtual environment application. The command language tool proved very flexible and facilitated an even distribution of effort and progress over time, but debugging and identification of errors was very difficult. Contrasting this, the direct manipulation tool enabled faster implementation of a first prototype but did not facilitate a shorter implementation process as a whole. On the basis of these findings, the strength and weaknesses of direct manipulation for developing virtual environment applications are explored further through a comparison with a successful direct manipulation tool for developing interactive multimedia applications. The comparisons are used to identify and emphasize key requirements for virtual environment development tool interface design.     

一种有效的P2P流媒体点播的供应者发现机制

提出了一种新的供应者发现机制,在源服务器上创建类似目录的数据结构维护系统中少量特定P2P节点的信息,用来锁定与目标供应者播放进度接近的节点,再通过这些节点的缓存交迭表与其邻近节点直接通信来找到合适的供应者。仿真实验结果表明,该供应者发现机制能够加快P2P节点的加入和恢复操作,且整个系统的通信负担明显降低。