Sample records for rdf-based e-learning p2p

  1. Integrating XQuery-enabled SCORM XML Metadata Repositories into an RDF-based E-Learning P2P Network

    Wolfgang Nejdl


    Full Text Available Edutella is an RDF-based E-Learning P2P network that is aimed to accommodate heterogeneous learning resource metadata repositories in a P2P manner and further facilitate the exchange of metadata between these repositories based on RDF. Whereas Edutella provides RDF metadata repositories with a quite natural integration approach, XML metadata repositories have to overcome considerable incompatibility between XML’s tree-like hierarchical data model and RDF’s binary relational data model in order to be integrated into Edutella. In this paper we investigate a generic approach for integrating XML metadata repositories into Edutella in terms of an XQuery-enabled native XML database containing SCORM XML metadata. We first propose a triple-like XML-based common data view to cross incompatibility between arbitrary XML data model and RDF data model, then discuss the wrapper program implementation for XML metadata repositories based on the wrapper-like Edutella content provider integration architecture. At last, we propose a generic approach for querying complex XML data schemas in Edutella through QBE (Query by Example, and present the design of a QBE-based SCORM query GUI that can be used to query SCORM XML metadata in Edutella in the RDF syntax.

  2. Saperi P2P

    Salvatore Iaconesi


    Full Text Available Il paper presenta l'architettura filosofica e logica di un progetto ongoing per la creazione di un'infrastruttura peer to peer per la diffusione dei saperi. Tale infrastruttura p2p vuole essere la base per costruire un framework aperto e orizzontale, che ospiti pratiche innovative di creazione, condivisione e disseminazione di informazioni e conoscenza.

  3. Towards P2P XML Database Technology

    Y. Zhang (Ying)


    textabstractTo ease the development of data-intensive P2P applications, we envision a P2P XML Database Management System (P2P XDBMS) that acts as a database middle-ware, providing a uniform database abstraction on top of a dynamic set of distributed data sources. In this PhD work, we research which

  4. P2P overlay over Simctl

    Sicart López, Gerard Carles


    This project intends to find and implement a p2p overlay over the simctl platform. Simctl is used both for teaching and research in the network engineering department. P2P systems became an interesting area since early 2000. Researchers conducted a large amount of research in some challenging areas and, to check their experiments, several implementations and simulators were created. Over time, Internet has evolved and P2P has been widely used for file sharing, but the main structured P2P o...

  5. Characterization of P2P Systems

    Stutzbach, Daniel; Rejaie, Reza

    The combination of large scale and geographically distributed nature of P2P system has led to their significant impact on the Internet. It is essential to characterize deployed P2P system for at least three reasons: (1) Accurately assessing their impact on the Internet, (2) identifying any performance bottleneck as well as any opportunity for performance improvement, (3) understanding user-driven dynamics in P2P systems. To characterize a P2P system, one needs to accurately capture snapshots of the resulting P2P overlay. This is challenging because the overlay is often large and dynamic. While the overlay is discovered by a crawler, it is changing which leads to a distorted view of the system. Capturing unbiased view of the traffic in the overlay is equally challenging because it is difficult to show that the captured behavior represent the observed behavior by all peers. In this chapter, we describe some of the fundamental problems in empirical characterization of widely deployed P2P systems. We present several examples to illustrate the effect of ad-hoc measurement/data collection on the resulting analysis/characterization. We then present two sampling techniques as a powerful approach to capture unbiased view of peer properties in a scalable fashion.

  6. P2P Techniques for Decentralized Applications

    Pacitti, Esther


    As an alternative to traditional client-server systems, Peer-to-Peer (P2P) systems provide major advantages in terms of scalability, autonomy and dynamic behavior of peers, and decentralization of control. Thus, they are well suited for large-scale data sharing in distributed environments. Most of the existing P2P approaches for data sharing rely on either structured networks (e.g., DHTs) for efficient indexing, or unstructured networks for ease of deployment, or some combination. However, these approaches have some limitations, such as lack of freedom for data placement in DHTs, and high late

  7. Data Sharing in P2P Systems

    Hayek, Rabab; Raschia, Guillaume; Valduriez, Patrick; Mouaddib, Noureddine

    In this chapter, we survey P2P data sharing systems. All along, we focus on the evolution from simple file-sharing systems, with limited functionalities, to Peer Data Management Systems (PDMS) that support advanced applications with more sophisticated data management techniques. Advanced P2P applications are dealing with semantically rich data (e.g., XML documents, relational tables), using a high-level SQL-like query language. We start our survey with an overview over the existing P2P network architectures, and the associated routing protocols. Then, we discuss data indexing techniques based on their distribution degree and the semantics they can capture from the underlying data. We also discuss schema management techniques which allow integrating heterogeneous data. We conclude by discussing the techniques proposed for processing complex queries (e.g., range and join queries). Complex query facilities are necessary for advanced applications which require a high level of search expressiveness. This last part shows the lack of querying techniques that allow for an approximate query answering.

  8. Localized Multistreams for P2P Streaming

    Majed Alhaisoni


    Full Text Available Streaming video over the Internet, including cellular networks, has now become a commonplace. Network operators typically use multicasting or variants of multiple unicasting to deliver streams to the user terminal in a controlled fashion. P2P streaming is an emerging alternative, which is theoretically more scalable but suffers from other issues arising from the dynamic nature of the system. Users' terminals become streaming nodes but they are not constantly connected. Another issue is that they are based on logical overlays, which are not optimized for the physical underlay infrastructure. An important proposition is to find effective ways to increase the resilience of the overlay whilst at the same time not conflicting with the network. In this article we look at the combination of two techniques, redundant streaming and locality awareness, in the context of both live and video-on-demand streaming. We introduce a new technique and assess it via a comparative, simulation-based study. We find that redundancy affects network utilization only marginally if traffic is kept at the edges via localization techniques.

  9. The ViP2P Platform: XML Views in P2P

    Karanasos, Konstantinos; Manolescu, Ioana; Zoupanos, Spyros


    The growing volumes of XML data sources on the Web or produced by enterprises, organizations etc. raise many performance challenges for data management applications. In this work, we are concerned with the distributed, peer-to-peer management of large corpora of XML documents, based on distributed hash table (or DHT, in short) overlay networks. We present ViP2P (standing for Views in Peer-to-Peer), a distributed platform for sharing XML documents based on a structured P2P network infrastructure (DHT). At the core of ViP2P stand distributed materialized XML views, defined by arbitrary XML queries, filled in with data published anywhere in the network, and exploited to efficiently answer queries issued by any network peer. ViP2P allows user queries to be evaluated over XML documents published by peers in two modes. First, a long-running subscription mode, when a query can be registered in the system and receive answers incrementally when and if published data matches the query. Second, queries can also be asked...

  10. Providing VoD Streaming Using P2P Networks

    Pedro Muñoz-Gea, Juan; Malgosa-Sanahuja, Josemaria; Manzanares-Lopez, Pilar; Carlos Sanchez-Aarnoutse, Juan

    Overlays and P2P systems, initially developed to support IP multicast and file-sharing, have moved beyond that functionality. They are also proving to be key technologies for the delivery of video streaming. Recently, there have been a number of successful deployments for "live" P2P streaming. However, the question remains open whether similar P2P technologies can be used to provide VoD (Video-On-Demand) services. A P2P VoD service is more challenging to design than a P2P live streaming system because the system should allow users arriving at arbitrary times to watch (arbitrary parts of) the video.

  11. Risk Management of P2P Internet Financing Service Platform

    Yalei, Li


    Since 2005, the world’s first P2P Internet financing service platform Zopa in UK was introduced, in the development of “Internet +” trend, P2P Internet financing service platform has been developed rapidly. In 2007, China’s first P2P platform “filming loan” was established, marking the P2P Internet financing service platform to enter China and the rapid development. At the same time, China’s P2P Internet financing service platform also appeared in different forms of risk. This paper focuses on the analysis of the causes of risk of P2P Internet financing service platform and the performance of risk management process. It provides a solution to the Internet risk management plan, and explains the risk management system of the whole P2P Internet financing service platform and the future development direction.

  12. Network-Aware DHT-Based P2P Systems

    Fayçal, Marguerite; Serhrouchni, Ahmed

    P2P networks lay over existing IP networks and infrastructure. This chapter investigates the relation between both layers, details the motivations for network awareness in P2P systems, and elucidates the requirements P2P systems have to meet for efficient network awareness. Since new P2P systems are mostly based on DHTs, we also present and analyse DHT-based architectures. And after a brief presentation of different existing network-awareness solutions, the chapter goes on effective cooperation between P2P traffic and network providers' business agreements, and introduces emerging DHT-based P2P systems that are network aware through a semantic defined for resource sharing. These new systems ensure also a certain context-awareness. So, they are analyzed and compared before an open end on prospects of network awareness in P2P systems.

  13. Research and Development of P2P Worms

    Li You; Zhi-Guang Qin


    With the development and the application of many popular peer-to-peer (P2P) systems such as eMule and BitTorrent,worms probably employ the features of these P2P networks to put them at risk.Some features,such as the local routing table and the application routing mechanism,are helpful to quickly distribute the P2P worms into the networks.This paper aims to give a comprehensive survey of P2P worms.The definition and the classification of P2P worms are discussed firstly.Then,the research and development of P2P worms, including experimental analysis,propagation modeling,and defensive approaches,are addressed and analyzed in detail.

  14. NCBI2RDF: Enabling Full RDF-Based Access to NCBI Databases

    Alberto Anguita; Miguel García-Remesal; Diana de la Iglesia; Victor Maojo


    RDF has become the standard technology for enabling interoperability among heterogeneous biomedical databases. The NCBI provides access to a large set of life sciences databases through a common interface called Entrez. However, the latter does not provide RDF-based access to such databases, and, therefore, they cannot be integrated with other RDF-compliant databases and accessed via SPARQL query interfaces. This paper presents the NCBI2RDF system, aimed at providing RDF-based access to the c...

  15. P2P Networking and Technology Enablers in Business Applications

    Hariharan, Mahesh


    The usage of Peer to Peer Networks over the Internet has been growing by exponentially. Apartbfrom the hype surrounding P2P, it has remarkable ramifications on the way the Internet could be used. This is an area which is not explored as well as we would want to. This thesis examines the architectural differences in P2P networks and generic application domains where the principles of P2P are exploited. The usage of P2P in different business verticals and technology enablers that go along with ...

  16. P2P worm detection based on application identification

    XIA Chunhe; SHI Yunping; LI Xiaojian; GAO Wei


    P2P worm exploits common vulnerabilities and spreads through peer-to-peer networks.Despite being recognized as a potential and deadly threat to the Internet recently,few relevant countermeasures are found in extant literature.Once it breaks out,a P2P worm could result in unpredictable losses.Based on propagation characteristics of the worm,this paper presents a detection method called PWD (P2P Worm Detection),which is designed based on application identification and unknown worm detection.Simulation result and LAN-environment experiment result both indicate that PWD is an effective method to detect and block P2P worms.

  17. Search by shortcuts in P2P scientific collaboration system


    A P2P scientific collaboration is a P2P network whose members can share documents, co-compile papers and codes, and communicate with each other instantly. From the simulation experiment we found that P2P collaboration system is a power-law network with a tail between -2 and -3.We utilized the algorithm that searches by high-degree shortcuts to improve the scalability of p2p collaboration system. The experimental result shows that the algorithm works better than random walk algorithm.

  18. Research of P2P SIP technology%P2P SIP技术的研究

    隋晋光; 鲁士文


    在阐述P2P和SIP技术的基础上,引出了一种二者融合的新技术--P2P SIP,提出了采用P2P SIP技术系统的体系结构、工作方式,并且对P2P SIP技术的安全性问题进行了分析.

  19. Queries mining for efficient routing in P2P communities

    Ismail, Anis; Durand, Nicolas; Nachouki, Gilles; Hajjar, Mohammad


    Peer-to-peer (P2P) computing is currently attracting enormous attention. In P2P systems a very large number of autonomous computing nodes (the peers) pool together their resources and rely on each other for data and services. Peer-to-peer (P2P) Data-sharing systems now generate a significant portion of Internet traffic. Examples include P2P systems for network storage, web caching, searching and indexing of relevant documents and distributed network-threat analysis. Requirements for widely distributed information systems supporting virtual organizations have given rise to a new category of P2P systems called schema-based. In such systems each peer exposes its own schema and the main objective is the efficient search across the P2P network by processing each incoming query without overly consuming bandwidth. The usability of these systems depends on effective techniques to find and retrieve data; however, efficient and effective routing of content-based queries is a challenging problem in P2P networks. This wo...

  20. Distributed Frequent Item Sets Mining over P2P Networks

    Zahra Farzanyar; Mohammadreza Kangavari


    Data intensive peer-to-peer (P2P) networks are becoming increasingly popular in applications like social networking, file sharing networks, etc. Data mining in such P2P environments is the new generation of advanced P2P applications. Unfortunately, most of the existing data mining algorithms do not fit well in such environments since they require data that can be accessed in its entirety. It also is not easy due to the requirements of online transactional data streams. In this paper, we have ...

  1. Increasing Structured P2P Protocol Resilience to Localized Attacks

    Germanus, Daniel


    The Peer-to-Peer (P2P) computing model has been applied to many application fields over the last decade. P2P protocols made their way from infamous - and frequently illicit - file sharing applications towards serious applications, e.g., in entertainment, audio/video conferencing, or critical applications like smart grid, Car-2-Car communication, or Machine-to-Machine communication. Some of the reasons for that are P2P's decentralized design that inherently provides for fault tolerance to non-...

  2. Code wars 10 years of P2P software litigation

    Giblin, Rebecca


    Code Wars recounts the legal and technological history of the first decade of the P2P file sharing era, focusing on the innovative and anarchic ways in which P2P technologies evolved in response to decisions reached by courts with regard to their predecessors. With reference to US, UK, Canadian and Australian secondary liability regimes, this insightful book develops a compelling new theory to explain why a decade of ostensibly successful litigation failed to reduce the number, variety or availability of P2P file sharing applications - and highlights ways the law might need to change if it is

  3. Comparing Pedophile Activity in Different P2P Systems

    Raphaël Fournier; Thibault Cholez; Matthieu Latapy; Isabelle Chrisment; Clémence Magnien; Olivier Festor; Ivan Daniloff


    International audience; Peer-to-peer (P2P) systems are widely used to exchange content over the Internet. Knowledge of pedophile activity in such networks remains limited, despite having important social consequences. Moreover, though there are different P2P systems in use, previous academic works on this topic focused on one system at a time and their results are not directly comparable. We design a methodology for comparing KAD and eDonkey, two P2P systems among the most prominent ones and ...

  4. Data Sharing in DHT Based P2P Systems

    Roncancio, Claudia; Del Pilar Villamil, María; Labbé, Cyril; Serrano-Alvarado, Patricia

    The evolution of peer-to-peer (P2P) systems triggered the building of large scale distributed applications. The main application domain is data sharing across a very large number of highly autonomous participants. Building such data sharing systems is particularly challenging because of the “extreme” characteristics of P2P infrastructures: massive distribution, high churn rate, no global control, potentially untrusted participants... This article focuses on declarative querying support, query optimization and data privacy on a major class of P2P systems, that based on Distributed Hash Table (P2P DHT). The usual approaches and the algorithms used by classic distributed systems and databases for providing data privacy and querying services are not well suited to P2P DHT systems. A considerable amount of work was required to adapt them for the new challenges such systems present. This paper describes the most important solutions found. It also identifies important future research trends in data management in P2P DHT systems.

  5. P2P Data Management in Mobile Wireless Sensor Network

    Nida Sahar Sayeda


    Full Text Available The rapid growth in wireless technologies has made wireless communication an important source for transporting data across different domains. In the same way, there are possibilities of many potential applications that can be deployed using WSNs (Wireless Sensor Networks. However, very limited applications are deployed in real life due to the uncertainty and dynamics of the environment and scare resources. This makes data management in WSN a challenging area to find an approach that suits its characteristics. Currently, the trend is to find efficient data management schemes using evolving technologies, i.e. P2P (Peer-to-Peer systems. Many P2P approaches have been applied in WSNs to carry out the data management due to similarities between WSN and P2P. With the similarities, there are differences too that makes P2P protocols inefficient in WSNs. Furthermore, to increase the efficiency and to exploit the delay tolerant nature of WSNs, where ever possible, the mobile WSNs are gaining importance. Thus, creating a three dimensional problem space to consider, i.e. mobility, WSNs and P2P. In this paper, an efficient algorithm is proposed for data management using P2P techniques for mobile WSNs. The real world implementation and deployment of proposed algorithm is also presented

  6. Network Awareness in P2P-TV Applications

    Traverso, Stefano; Leonardi, Emilio; Mellia, Marco; Meo, Michela

    The increasing popularity of applications for video-streaming based on P2P paradigm (P2P-TV) is raising the interest of both broadcasters and network operators. The former see a promising technology to reduce the cost of streaming content over the Internet, while offering a world-wide service. The latter instead fear that the traffic offered by these applications can grow without control, affecting other services, and possibly causing network congestion and collapse. The “Network-Aware P2P-TV Application over Wise Networks” FP7 project aims at studying and developing a novel P2P-TV application offering the chance to broadcast high definition video to broadcasters and to carefully manage the traffic offered by peers to the network, therefore avoiding worries to Internet providers about network overload. In such context, we design a simulator to evaluate performance of different P2P-TV solutions, to compare them both considering end-users’ and network providers’ perspectives, such as quality of service perceived by subscribers and link utilization. In this paper, we provide some results that show how effective can be a network aware P2P-TV system.

  7. Improving P2P live-content delivery using SVC

    Schierl, T.; Sánchez, Y.; Hellge, C.; Wiegand, T.


    P2P content delivery techniques for video transmission have become of high interest in the last years. With the involvement of client into the delivery process, P2P approaches can significantly reduce the load and cost on servers, especially for popular services. However, previous studies have already pointed out the unreliability of P2P-based live streaming approaches due to peer churn, where peers may ungracefully leave the P2P infrastructure, typically an overlay networks. Peers ungracefully leaving the system cause connection losses in the overlay, which require repair operations. During such repair operations, which typically take a few roundtrip times, no data is received from the lost connection. While taking low delay for fast-channel tune-in into account as a key feature for broadcast-like streaming applications, the P2P live streaming approach can only rely on a certain media pre-buffer during such repair operations. In this paper, multi-tree based Application Layer Multicast as a P2P overlay technique for live streaming is considered. The use of Flow Forwarding (FF), a.k.a. Retransmission, or Forward Error Correction (FEC) in combination with Scalable video Coding (SVC) for concealment during overlay repair operations is shown. Furthermore the benefits of using SVC over the use of AVC single layer transmission are presented.

  8. Characterization of P2P IPTV Traffic: Scaling Analysis

    Silverston, Thomas; Salamatian, Kave


    P2P IPTV applications arise on the Internet and will be massively used in the future. It is expected that P2P IPTV will contribute to increase the overall Internet traffic. In this context, it is important to measure the impact of P2P IPTV on the networks and to characterize this traffic. During the 2006 FIFA World Cup, we performed an extensive measurement campaign. We measured network traffic generated by broadcasting soccer games by the most popular P2P IPTV applications, namely PPLive, PPStream, SOPCast and TVAnts. From the collected data, we characterized the P2P IPTV traffic structure at different time scales. To the best of our knowledge, this is the first work, which presents a complete multiscale analysis of the P2P IPTV traffic. Our observations show that the network traffic has not the same scale behavior whether the applications use TCP or UDP. For all the applications, the download traffic is different from the upload traffic and the signaling traffic has an impact on the download traffic.

  9. Determinants of Default in P2P Lending.

    Serrano-Cinca, Carlos; Gutiérrez-Nieto, Begoña; López-Palacios, Luz


    This paper studies P2P lending and the factors explaining loan default. This is an important issue because in P2P lending individual investors bear the credit risk, instead of financial institutions, which are experts in dealing with this risk. P2P lenders suffer a severe problem of information asymmetry, because they are at a disadvantage facing the borrower. For this reason, P2P lending sites provide potential lenders with information about borrowers and their loan purpose. They also assign a grade to each loan. The empirical study is based on loans' data collected from Lending Club (N = 24,449) from 2008 to 2014 that are first analyzed by using univariate means tests and survival analysis. Factors explaining default are loan purpose, annual income, current housing situation, credit history and indebtedness. Secondly, a logistic regression model is developed to predict defaults. The grade assigned by the P2P lending site is the most predictive factor of default, but the accuracy of the model is improved by adding other information, especially the borrower's debt level.

  10. Determinants of Default in P2P Lending.

    Carlos Serrano-Cinca

    Full Text Available This paper studies P2P lending and the factors explaining loan default. This is an important issue because in P2P lending individual investors bear the credit risk, instead of financial institutions, which are experts in dealing with this risk. P2P lenders suffer a severe problem of information asymmetry, because they are at a disadvantage facing the borrower. For this reason, P2P lending sites provide potential lenders with information about borrowers and their loan purpose. They also assign a grade to each loan. The empirical study is based on loans' data collected from Lending Club (N = 24,449 from 2008 to 2014 that are first analyzed by using univariate means tests and survival analysis. Factors explaining default are loan purpose, annual income, current housing situation, credit history and indebtedness. Secondly, a logistic regression model is developed to predict defaults. The grade assigned by the P2P lending site is the most predictive factor of default, but the accuracy of the model is improved by adding other information, especially the borrower's debt level.

  11. Determinants of Default in P2P Lending


    This paper studies P2P lending and the factors explaining loan default. This is an important issue because in P2P lending individual investors bear the credit risk, instead of financial institutions, which are experts in dealing with this risk. P2P lenders suffer a severe problem of information asymmetry, because they are at a disadvantage facing the borrower. For this reason, P2P lending sites provide potential lenders with information about borrowers and their loan purpose. They also assign a grade to each loan. The empirical study is based on loans’ data collected from Lending Club (N = 24,449) from 2008 to 2014 that are first analyzed by using univariate means tests and survival analysis. Factors explaining default are loan purpose, annual income, current housing situation, credit history and indebtedness. Secondly, a logistic regression model is developed to predict defaults. The grade assigned by the P2P lending site is the most predictive factor of default, but the accuracy of the model is improved by adding other information, especially the borrower’s debt level. PMID:26425854

  12. Managing Linguistic Data Summaries in Advanced P2P Applications

    Hayek, Rabab; Raschia, Guillaume; Valduriez, Patrick; Mouaddib, Noureddine

    As the amount of stored data increases, data localization techniques become no longer sufficient in P2P systems. A practical approach is to rely on compact database summaries rather than raw database records, whose access is costly in large P2P systems. In this chapter, we describe a solution for managing linguistic data summaries in advanced P2P applications which are dealing with semantically rich data. The produced summaries are synthetic, multidimensional views over relational tables. The novelty of this proposal relies on the double summary exploitation in distributed P2P systems. First, as semantic indexes, they support locating relevant nodes based on their data descriptions. Second, due to their intelligibility, these summaries can be directly queried and thus approximately answer a query without the need for exploring original data. The proposed solution consists first in defining a summary model for hierarchical P2P systems. Second, appropriate algorithms for summary creation and maintenance are presented. A query processing mechanism, which relies on summary querying, is then proposed to demonstrate the benefits that might be obtained from summary exploitation.

  13. Behavioural Correlation for Detecting P2P Bots

    Al-Hammadi, Yousof


    In the past few years, IRC bots, malicious programs which are remotely controlled by the attacker through IRC servers, have become a major threat to the Internet and users. These bots can be used in different malicious ways such as issuing distributed denial of services attacks to shutdown other networks and services, keystrokes logging, spamming, traffic sniffing cause serious disruption on networks and users. New bots use peer to peer (P2P) protocols start to appear as the upcoming threat to Internet security due to the fact that P2P bots do not have a centralized point to shutdown or traceback, thus making the detection of P2P bots is a real challenge. In response to these threats, we present an algorithm to detect an individual P2P bot running on a system by correlating its activities. Our evaluation shows that correlating different activities generated by P2P bots within a specified time period can detect these kind of bots.

  14. A Framework For Concept Drifting P2P Traffic Identification

    Guanghui Yan


    Full Text Available Identification of network traffic using port-based or payload-based analysis is becoming increasing difficult with many Peer-to-Peer (P2P application using dynamic ports, masquerading techniques, and encryption to avoid detection. To overcome this problem, several machine learning technique were proposed to classify P2P traffics. But in the real P2P network environment, new communities of peers often attend and old communities of peers often leave. It requires the identification methods to be capable of coping with concept drift, and updating the model incrementally. In this paper, we present a concept-adapting algorithm CluMC which is based on streaming data mining techniques to identify P2P applications in Internet traffic. The CluMC use micro-cluster structures which contain potential micro-cluster structures and outlier micro-cluster structures to classify the P2P traffic and discover the concept drift with limited memory. Our performance study over a number of real data sets that we captured at a main gateway router demonstrates the effectiveness and efficiency of our method.

  15. Market Design for a P2P Backup System

    Seuken, Sven; Charles, Denis; Chickering, Max; Puri, Sidd

    Peer-to-peer (P2P) backup systems are an attractive alternative to server-based systems because the immense costs of large data centers can be saved by using idle resources on millions of private computers instead. This paper presents the design and theoretical analysis of a market for a P2P backup system. While our long-term goal is an open resource exchange market using real money, here we consider a system where monetary transfers are prohibited. A user who wants to backup his data must in return supply some of his resources (storage space, upload and download bandwidth) to the system.We propose a hybrid P2P architecture where all backup data is transferred directly between peers, but a dedicated server coordinates all operations and maintains meta-data. We achieve high reliability guarantees while keeping our data replication factor low by adopting sophisticated erasure coding technology (cf., [2]).

  16. PROSE: Proactive, Selective CDN Participation for P2P Streaming

    Zhi-Hui Lv; Li-Jiang Chen; Jie Wu; Da Deng; Si-Jia Huang; Yi Huang


    Many production peer-to-peer (P2P) streaming systems use content delivery networks (CDN) to protect the user's quality of experiences.Thus,how to efficiently utilize the capacity of CDN (e.g.,which peers receive services from the CDN nodes) is a problem of practical significance.Existing solutions adopt a passive,on-demand approach,which is inefficient iu utilizing CDN resources.In this paper,we propose PROSE,a simple,novel scheme to achieve proactive,selective CDN participation for P2P streaming.PROSE introduces novel concepts such as choke point expansion nodes/super nodes and leads to efficient,light-weighted,and distributed algorithms to identify and serve these nodes using CDN.Our experimental results show that PROSE achieves at least 10%~25% performance improvement and 2~4 times overhead reduction compared with existing general CDN-P2P-hybrid schemes.

  17. Model of Controlling the Hubs in P2P Networks

    Yuhua Liu


    Full Text Available Research into the hubs in Peer-to-Peer (P2P networks, and present a new method to avoid generating the hubs in the networks by controlling the logical topology structure of P2P networks. We firstly introduce the controlling ideas about hierarchizing the hubs. Then, we disclose and interpret the controlling model, and give out the concrete method to carry it out. Finally, we validate our controlling model via simulations and the simulation results demonstrate that our work is effective to control the hubs in P2P networks. Thus, this model can improve the network competence to defend against coordinated attacks, promote the network robustness, and ensure the network would develop continually and healthily.

  18. On Using Seeders for P2P Live Streaming

    Mathieu, Fabien


    Seeders (peers that do not request anything but contribute to the system) are a powerful concept in peer-to-peer (P2P). They allow to leverage the capacities of a P2P system. While seeding is a natural idea for filesharing or video-on-demand applications, it seems somehow counter-intuitive in the context of live streaming. This paper aims at describing the feasibility and performance of P2P live seeding. After a formal definition of "live seeding" and efficiency, we consider the theoretical performance of systems where the overhead is neglected. We then propose a linear overhead model and extend the results for this model, for a single seeder and for a set of seeders as well (it is not always possible to perfectly aggregate individual efficiencies in a given system).

  19. Compromising Tor Anonymity Exploiting P2P Information Leakage

    Manils, Pere; Blond, Stevens Le; Kaafar, Mohamed Ali; Castelluccia, Claude; Legout, Arnaud; Dabbous, Walid


    Privacy of users in P2P networks goes far beyond their current usage and is a fundamental requirement to the adoption of P2P protocols for legal usage. In a climate of cold war between these users and anti-piracy groups, more and more users are moving to anonymizing networks in an attempt to hide their identity. However, when not designed to protect users information, a P2P protocol would leak information that may compromise the identity of its users. In this paper, we first present three attacks targeting BitTorrent users on top of Tor that reveal their real IP addresses. In a second step, we analyze the Tor usage by BitTorrent users and compare it to its usage outside of Tor. Finally, we depict the risks induced by this de-anonymization and show that users' privacy violation goes beyond BitTorrent traffic and contaminates other protocols such as HTTP.

  20. Mobile P2P Web Services Using SIP

    Guido Gehlen


    Full Text Available Telecommunication networks and the Internet are growing together. Peer-to-Peer (P2P services which are originally offered by network providers, like telephony and messaging, are provided through VoIP and Instant Messaging (IM by Internet service providers, too. The IP Multimedia Subsystem (IMS is the answer of the telecommunication industry to this trend and aims at providing Internet P2P and multimedia services controlled by the network operators. The IMS provides mobility and session management as well as message routing, security, and billing.

  1. On the {P2, P3}-Factor of Cubic Graphs

    GOU Kui-xiang; SUN Liang


    Let G = ( V, E) be a finite simple graph and Pn denote the path of order n. A spanning subgraph F is called a {P2, P3}-factor of G if each component of F is isomorphic to P2 or P3. With the path-covering method, it is proved that any connected cubic graph with at least 5 vertices has a { P2, P3 }-factor F such that | P3 (F) |≥|P2 (F) |, where P2 (F) and P3 (F) denote the set of components of P2 and P3 in F,respectively.

  2. Measurement and Analysis of P2P IPTV Program Resource

    Wenxian Wang


    Full Text Available With the rapid development of P2P technology, P2P IPTV applications have received more and more attention. And program resource distribution is very important to P2P IPTV applications. In order to collect IPTV program resources, a distributed multi-protocol crawler is proposed. And the crawler has collected more than 13 million pieces of information of IPTV programs from 2009 to 2012. In addition, the distribution of IPTV programs is independent and incompact, resulting in chaos of program names, which obstructs searching and organizing programs. Thus, we focus on characteristic analysis of program resources, including the distributions of length of program names, the entropy of the character types, and hierarchy depth of programs. These analyses reveal the disorderly naming conventions of P2P IPTV programs. The analysis results can help to purify and extract useful information from chaotic names for better retrieval and accelerate automatic sorting of program and establishment of IPTV repository. In order to represent popularity of programs and to predict user behavior and popularity of hot programs over a period, we also put forward an analytical model of hot programs.

  3. P2P Domain Classification using Decision Tree

    Ismail, Anis


    In Peer-to-Peer context, a challenging problem is how to find the appropriate peer to deal with a given query without overly consuming bandwidth? Different methods proposed routing strategies of queries taking into account the P2P network at hand. This paper considers an unstructured P2P system based on an organization of peers around Super-Peers that are connected to Super-Super- Peer according to their semantic domains; By analyzing the queries log file, a predictive model that avoids flooding queries in the P2P network is constructed after predicting the appropriate Super-Peer, and hence the peer to answer the query. A challenging problem in a schema-based Peer-to-Peer (P2P) system is how to locate peers that are relevant to a given query. In this paper, architecture, based on (Super-)Peers is proposed, focusing on query routing. The approach to be implemented, groups together (Super-)Peers that have similar interests for an efficient query routing method. In such groups, called Super-Super-Peers (SSP), Su...

  4. Comparing Pedophile Activity in Different P2P Systems

    Raphaël Fournier


    Full Text Available Peer-to-peer (P2P systems are widely used to exchange content over the Internet. Knowledge of pedophile activity in such networks remains limited, despite having important social consequences. Moreover, though there are different P2P systems in use, previous academic works on this topic focused on one system at a time and their results are not directly comparable. We design a methodology for comparing KAD and eDonkey, two P2P systems among the most prominent ones and with different anonymity levels. We monitor two eDonkey servers and the KAD network during several days and record hundreds of thousands of keyword-based queries. We detect pedophile-related queries with a previously validated tool and we propose, for the first time, a large-scale comparison of pedophile activity in two different P2P systems. We conclude that there are significantly fewer pedophile queries in KAD than in eDonkey (approximately 0.09% vs. 0.25%.

  5. Measurement and Analysis of P2P IPTV Program Resource

    Chen, Xingshu; Wang, Haizhou; Zhang, Qi


    With the rapid development of P2P technology, P2P IPTV applications have received more and more attention. And program resource distribution is very important to P2P IPTV applications. In order to collect IPTV program resources, a distributed multi-protocol crawler is proposed. And the crawler has collected more than 13 million pieces of information of IPTV programs from 2009 to 2012. In addition, the distribution of IPTV programs is independent and incompact, resulting in chaos of program names, which obstructs searching and organizing programs. Thus, we focus on characteristic analysis of program resources, including the distributions of length of program names, the entropy of the character types, and hierarchy depth of programs. These analyses reveal the disorderly naming conventions of P2P IPTV programs. The analysis results can help to purify and extract useful information from chaotic names for better retrieval and accelerate automatic sorting of program and establishment of IPTV repository. In order to represent popularity of programs and to predict user behavior and popularity of hot programs over a period, we also put forward an analytical model of hot programs. PMID:24772008

  6. Theatrical distribution and P2P movie piracy: a survey of P2P networks in Hungary using transactional data

    Bodó, B.; Lakatos, Z.


    This article examines what appears to be the most important factor shaping file sharing: the failure of traditional cultural markets to efficiently supply the demand in the online environment. Its findings are based on tracking the traffic of movies on three Hungarian P2P networks. This dataset is t

  7. Theatrical distribution and P2P movie piracy: a survey of P2P networks in Hungary using transactional data

    Bodó, B.; Lakatos, Z.


    This article examines what appears to be the most important factor shaping file sharing: the failure of traditional cultural markets to efficiently supply the demand in the online environment. Its findings are based on tracking the traffic of movies on three Hungarian P2P networks. This dataset is t



    The letter proposes a three-layer manageable media distribution network system architecture called MSPnet, which is based on Session Initiation Protocol[1] and Peer to Peer (SIP P2P)technology. MSPnet performs application-level structured DHT routing and resource location among domains and unstructured ones in domain. Except for media distribution, it can be used to support a variety of P2P applications, including video broadcasting, video on demand, VoIP, etc. MSPnet is composed of three layers, namely, the signal control layer, the management layer, and the media transportation layer. The MSPnet prototype consists of the SIP server, the management server, the media server, and the node User Agent (UA). Results from a prototype experiment in a large-scale Internet environment show that MSPnet is feasible, scalable and manageable.

  9. Mobile P2P Trusted On-Demand Video Streaming

    Iyer, Thava; Rizvandi, Nikzad Babaii; Varghese, Benoy; Boreli, Roksana


    We propose to demonstrate a mobile server assisted P2P system for on-demand video streaming. Our proposed solution uses a combination of 3G and ad-hoc Wi-Fi connections, to enable mobile devices to download content from a centralised server in a way that minimises the 3G bandwidth use and cost. On the customised GUI, we show the corresponding reduction in 3G bandwidth achieved by increasing the number of participating mobile devices in the combined P2P and ad-hoc Wi- Fi network, while demonstrating the good video playout quality on each of the mobiles. We also demonstrate the implemented trust mechanism which enables mobiles to only use trusted adhoc connections. The system has been implemented on Android based smartphones.

  10. Supporting Seamless Mobility for P2P Live Streaming

    Eunsam Kim


    Full Text Available With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme.

  11. Supporting seamless mobility for P2P live streaming.

    Kim, Eunsam; Kim, Sangjin; Lee, Choonhwa


    With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme.

  12. Addressing the P2P Bootstrap Problem for Small Networks

    Wolinsky, David Isaac; Boykin, P Oscar; Figueiredo, Renato


    P2P overlays provide a framework for building distributed applications consisting of few to many resources with features including self-configuration, scalability, and resilience to node failures. Such systems have been successfully adopted in large-scale services for content delivery networks, file sharing, and data storage. In small-scale systems, they can be useful to address privacy concerns and for network applications that lack dedicated servers. The bootstrap problem, finding an existing peer in the overlay, remains a challenge to enabling these services for small-scale P2P systems. In large networks, the solution to the bootstrap problem has been the use of dedicated services, though creating and maintaining these systems requires expertise and resources, which constrain their usefulness and make them unappealing for small-scale systems. This paper surveys and summarizes requirements that allow peers potentially constrained by network connectivity to bootstrap small-scale overlays through the use of e...

  13. P2P Networks with IP Based Communication

    Anupriya Koneru; Krishna Prasad MHM


    P2P communities can be seen as truly Distributed Computing applications in which group members communicate with one another to exchange information. The authors consider security issues in Peer to Peer Networks. For secure exchange of data between the group members the authors present a cryptography protocol and an Identity mechanism which can able to check even the Trust of the Peers based on the available reputation information. The authors are encapsulating the reputations of both the prov...

  14. Pure P2P mediation system: A mappings discovery approach

    selma, El yahyaoui El idrissi; Zellou, Ahmed; Idri, Ali


    The information integration systems consist in offering a uniform interface to provide access to a set of autonomous and distributed information sources. The most important advantage of this system is that it allows users to specify what they want, rather than thinking about how to get the responses. The works realized in this area have particular leads to two major classes of integration systems: the mediation systems based on the paradigm mediator / adapter and peer to peer systems (P2P). The combination of both systems has led to a third type; is the mediation P2P systems. The P2P systems are large-scale systems, self-organized and distributed. They allow the resource management in a completely decentralized way. However, the integration of structured information sources, heterogeneous and distributed proves to be a complex problem. The objective of this work is to propose an approach to resolve conflicts and establish a mapping between the heterogeneous elements. This approach is based on clustering; the latter is to group similar Peers that share common information in the same subnet. Thus, to facilitate the heterogeneity, we introduced three additional layers of our hierarchy of peers: internal schema, external schema and Schema directory peer. We used linguistic techniques, and precisely the name correspondence technique, that is based on the similarity of names to propose a correspondence.

  15. Uniform Sampling for Directed P2P Networks

    Hall, Cyrus; Carzaniga, Antonio

    Selecting a random peer with uniform probability across a peer-to-peer (P2P) network is a fundamental function for unstructured search, data replication, and monitoring algorithms. Such uniform sampling is supported by several techniques. However, current techniques suffer from sample bias and limited applicability. In this paper, we present a sampling algorithm that achieves a desired uniformity while making essentially no assumptions about the underlying P2P network. This algorithm, called doubly stochastic converge (DSC), iteratively adjusts the probabilities of crossing each link in the network during a random walk, such that the resulting transition matrix is doubly stochastic. DSC is fully decentralized and is designed to work on both directed and undirected topologies, making it suitable for virtually any P2P network. Our simulations show that DSC converges quickly on a wide variety of topologies, and that the random walks needed for sampling are short for most topologies. In simulation studies with FreePastry, we show that DSC is resilient to high levels of churn, while incurring a minimal sample bias.

  16. Random walk search in unstructured P2P

    Jia Zhaoqing; You Jinyuan; Rao Ruonan; Li Minglu


    Unstructured P2P has power-law link distribution, and the random walk in power-law networks is analyzed. The analysis results show that the probability that a random walker walks through the high degree nodes is high in the power-law network, and the information on the high degree nodes can be easily found through random walk. Random walk spread and random walk search method (RWSS) is proposed based on the analysis result. Simulation results show that RWSS achieves high success rates at low cost and is robust to high degree node failure.

  17. Efficient Search in P2P File Sharing System

    Xiao Bo; Jin Wei; Hou Mengshu


    A new routing algorithm of peer-to-peer file sharing system with routing indices was proposed, in which a node forwards a query to neighbors that are more likely to have answers based on its statistics. The proposed algorithm was tested by creating a P2P simulator and varying the input parameters, and was compared to the search algorithms using flooding (FLD) and random walk (RW). The result shows that with the proposed design, the queries are routed effectively, the network flows are reduced remarkably, and the peer-to-peer file sharing system gains a good expansibility.

  18. Supporting Personal Semantic Annotations in P2P Semantic Wikis

    Torres, Diego; Skaf-Molli, Hala; Díaz, Alicia; Molli, Pascal

    In this paper, we propose to extend Peer-to-Peer Semantic Wikis with personal semantic annotations. Semantic Wikis are one of the most successful Semantic Web applications. In semantic wikis, wikis pages are annotated with semantic data to facilitate the navigation, information retrieving and ontology emerging. Semantic data represents the shared knowledge base which describes the common understanding of the community. However, in a collaborative knowledge building process the knowledge is basically created by individuals who are involved in a social process. Therefore, it is fundamental to support personal knowledge building in a differentiated way. Currently there are no available semantic wikis that support both personal and shared understandings. In order to overcome this problem, we propose a P2P collaborative knowledge building process and extend semantic wikis with personal annotations facilities to express personal understanding. In this paper, we detail the personal semantic annotation model and show its implementation in P2P semantic wikis. We also detail an evaluation study which shows that personal annotations demand less cognitive efforts than semantic data and are very useful to enrich the shared knowledge base.

  19. An Effective Calculation of Reputation in P2P Networks

    RVVSV Prasad


    Full Text Available With the advent of sophisticated networking technologies and the related applications, more and more computers are getting hooked to the Internet. This is mainly for utilizing several services ranging from information sharing to electronic transactions. P2P networks which allow decentralized systems, have posed problems related to trust when transactions have to be carried out. Current literature proposes several solutions for trust management and reputation computation. The solutions base their assessment of reputations on the number of successful transactions or on the similarity of the feedbacks. There are some concerns in the feedback ratings if we are not considering the issues like number of transactions, frequency of transactions with the same peer and different peers, age of transaction, how frequently a given peer attends a common vendor, and the number of common vendors between the pairs. This paper puts forward a reputation computation system addressing these concerns. It implicitly allows detection of malicious peers. It also incorporates a corrective mechanism, if the feedbacks are from more number of malicious peers. The implementations and the results that support our claims are also presented.

  20. Survey on Distributed Data Mining in P2P Networks

    T, Rekha Sunny


    The exponential increase of availability of digital data and the necessity to process it in business and scientific fields has literally forced upon us the need to analyze and mine useful knowledge from it. Traditionally data mining has used a data warehousing model of gathering all data into a central site, and then running an algorithm upon that data. Such a centralized approach is fundamentally inappropriate due to many reasons like huge amount of data, infeasibility to centralize data stored at multiple sites, bandwidth limitation and privacy concerns. To solve these problems, Distributed Data Mining (DDM) has emerged as a hot research area. Careful attention in the usage of distributed resources of data, computing, communication, and human factors in a near optimal fashion are paid by distributed data mining. DDM is gaining attention in peer-to-peer (P2P) systems which are emerging as a choice of solution for applications such as file sharing, collaborative movie and song scoring, electronic commerce, an...

  1. Improved Degree Search Algorithms in Unstructured P2P Networks

    Guole Liu


    Full Text Available Searching and retrieving the demanded correct information is one important problem in networks; especially, designing an efficient search algorithm is a key challenge in unstructured peer-to-peer (P2P networks. Breadth-first search (BFS and depth-first search (DFS are the current two typical search methods. BFS-based algorithms show the perfect performance in the aspect of search success rate of network resources, while bringing the huge search messages. On the contrary, DFS-based algorithms reduce the search message quantity and also cause the dropping of search success ratio. To address the problem that only one of performances is excellent, we propose two memory function degree search algorithms: memory function maximum degree algorithm (MD and memory function preference degree algorithm (PD. We study their performance including the search success rate and the search message quantity in different networks, which are scale-free networks, random graph networks, and small-world networks. Simulations show that the two performances are both excellent at the same time, and the performances are improved at least 10 times.

  2. Peer behavior based proactive P2P worm detection%基于节点行为的主动 P2P 蠕虫检测

    朱晖; 李伟华; 史豪斌


    Proactive P2P worm propagation is a serious security threat to P2P network and Internet. By researching the peer be-havior of propagating proactive P2P worm, this paper puts forward PBD(Peer Behavior based Detection)to detect proactive P2P worm. On this basis, it designs and implements a PPWDS(Proactive P2P Worm Detection System). This system adopts CUSUM algorithm to carry out real time monitoring to the outbound short link of P2P peers. Experiments show that PBD is an effective method of proactive P2P worm detect.%  主动 P2P 蠕虫的传播会对 P2P 网络以及互联网的安全造成严重威胁。通过研究主动 P2P 蠕虫传播时节点行为,提出一种基于节点行为的主动 P2P 蠕虫检测方法 PBD(Peer Behavior based Detection)。在此基础上设计和实现了一个主动 P2P 蠕虫检测系统 PPWDS(Proactive P2P Worm Detection System),该系统采用 CUSUM 算法对 P2P 节点出站短连接进行实时监控。实验表明,PBD 是检测主动 P2P 蠕虫的一种有效方法。

  3. NCBI2RDF: enabling full RDF-based access to NCBI databases.

    Anguita, Alberto; García-Remesal, Miguel; de la Iglesia, Diana; Maojo, Victor


    RDF has become the standard technology for enabling interoperability among heterogeneous biomedical databases. The NCBI provides access to a large set of life sciences databases through a common interface called Entrez. However, the latter does not provide RDF-based access to such databases, and, therefore, they cannot be integrated with other RDF-compliant databases and accessed via SPARQL query interfaces. This paper presents the NCBI2RDF system, aimed at providing RDF-based access to the complete NCBI data repository. This API creates a virtual endpoint for servicing SPARQL queries over different NCBI repositories and presenting to users the query results in SPARQL results format, thus enabling this data to be integrated and/or stored with other RDF-compliant repositories. SPARQL queries are dynamically resolved, decomposed, and forwarded to the NCBI-provided E-utilities programmatic interface to access the NCBI data. Furthermore, we show how our approach increases the expressiveness of the native NCBI querying system, allowing several databases to be accessed simultaneously. This feature significantly boosts productivity when working with complex queries and saves time and effort to biomedical researchers. Our approach has been validated with a large number of SPARQL queries, thus proving its reliability and enhanced capabilities in biomedical environments.

  4. Non-P2P network applicationautomatic feature recognition%非 P2P 网络应用自动化特征提取

    丁斌; 焦素云; 闫晓亮


    在对流量进行分类的基础上,应用Apriori算法分析分类以后的非P2P流,能够更准确地分析出非P2 P的网络应用特征。%Based on the classified traffic flow between P2P and non‐P2P ,Apriori algorithm is used to analyzing the non‐P2P flow to get the high precise characteristics of non‐P2P network application .

  5. Music2Share - Copyright-Compliant Music Sharing in P2P Systems

    Kalker, Ton; Epema, Dick H.J.; Hartel, Pieter H.; Lagendijk, R. (Inald) L.; van Steen, Martinus Richardus; van Steen, Maarten


    Peer-to-Peer (P2P) networks are generally considered to be free havens for pirated content, in particular with respect to music. We describe a solution for the problem of copyright infringement in P2P networks for music sharing. In particular, we propose a P2P protocol that integrates the functions

  6. An agent-based incentive mechanism for P2P systems

    ZHANG Jian-feng; WANG Ru-chuan


    With the increasing uses of peer-to-peer (P2P)systems, the problems of fair information and resources sharing become serious. P2P systems are self-organizing,distributed systems with no centralized authority, such as Free-riding and Tragedy of Commons. Because of the voluntary participation and lack of motivation, the information and resources available in P2P networks are extremely variable and unpredictable. This article studied the problems existing in P2P networks and propose a different method to stimulate the peers in P2P networks to share information and resources,using agents so as to improve the performance of P2P networks.And through simulation experiments and analyzing the results,it can be concluded that this mechanism can effectively solve the problems of fair sharing in P2P systems.

  7. 非结构化P2P Overlay拓扑结构分析%Analysis of Topology Structure in Unstructured P2P Overlay

    姜卫; 王观玉; 宋世延


    一个合理的P2P overlay可以为P2P应用提供更好的支持.非结构化P2P overlay的构建比较简单随意,适合于信息发布、即时通讯等节点随时加入退出的情况.构建具有可扩展性和稳健性的网络拓扑,是非结构化P2P overlay的研究热点之一.文章首先介绍了几种典型的非结构化P2P overlay,然后与以往研究不同,通过GT-ITM建模分析了每种P2P overlay拓扑结构的性能,主要分析了不同拓扑结构节点的度、最短路径分布、节点发现概率及结构的健壮性等,该工作对构造合理的P2P overlay拓扑结构和P2P系统的研究具有重要意义.

  8. Optimized Grid Based e-Learning Framework

    Suresh Jaganathan


    Full Text Available E-Learning is the process of extending the resources to different locations by using multimedia communications. Many e-Learning methodologies are available and based on client-server, peer-to-peer and using Grid Computing concepts. To establish e-Learning process, systems should satisfy these needs, i high storage for storing, ii high network throughput for faster transfer and iii efficient streaming of materials. The first and second needs are satisfied by using Grid and P2P technologies and the third need can be achieved by an efficient video compression algorithm. This study proposes a framework, called Optimized Grid Based e-Learning (OgBeL , which adopts both Grid and P2P technology. To reduce the e-Learning material size for efficient streaming, a light weight compression algorithm called (dWave is embedded in (OgBeL . The behavior of framework is analyzed in terms of time taken to transfer files using in-use grid protocols and in networks combined with grid and P2P.

  9. Analysis and Design of Instant Message System Based on P2P

    Shen Zhiwei; Ma Shaowu


    By analyzing current development conditions of mainstream Instant Message technologies and services, some detailed discussion about technical solution and formal operation deployment strategies of P2P Instant Message Services based on Interact is made. Several crucial problems of P2P Instant Message System about services management, interconnection with other instant message, security and profit-making mode are analyzed,, and how to develop P2P IM Services is proposed.

  10. IPTV-RM: A Resources Monitoring Architecture for P2P IPTV Systems


    Resources monitoring is an important problem of the overall efficient usage and control of P2P IPTV systems. The resources of IPTV can include all distributing servers, programs and peers. Several researches have tried to address this issue, but most of them illuminated P2P traffic characterization, identification and user behavior. The main contributions of this paper are twofold. Firstly, a resources monitoring architecture for P2P IPTV systems, IPTV-RM, was presented based on previous work...

  11. OMAN - A Management Architecture for P2P Service Overlay Networks

    Fiorese, Adriano; Simões, Paulo; Boavida, Fernando


    International audience; In a world where networking services are increasingly being provided by service overlay networks, management of these services at overlay level is becoming crucially important. This paper presents an architecture for services management in P2P Service Overlay Networks (SON). The architecture, named OMAN, takes into account the formation of the P2P SON comprising several different service providers belonging to several different network domains. It uses P2P mechanisms t...

  12. Survey of Search and Replication Schemes in Unstructured P2P Networks

    Thampi, Sabu M


    P2P computing lifts taxing issues in various areas of computer science. The largely used decentralized unstructured P2P systems are ad hoc in nature and present a number of research challenges. In this paper, we provide a comprehensive theoretical survey of various state-of-the-art search and replication schemes in unstructured P2P networks for file-sharing applications. The classifications of search and replication techniques and their advantages and disadvantages are briefly explained. Finally, the various issues on searching and replication for unstructured P2P networks are discussed.

  13. An Optimized and Improved Network Trust Model Based on P2P

    Li Wei


    Full Text Available Because of the spring up of the P2P network application, its open, anonymous and self-organized characteristics has offered a path for the spreading of virus and junk data, and the security has aroused people’s common concern. The traditional network trust model dealt with dishonest node has certain limitation, for this, improved P2P network trust model and applied D-S evidence theory to the trusted computing of trust model. Through simulation experiment, the result showed: the improved P2P network trust model efficiently increased the successful trading rate of P2P network and improved the network environment

  14. Phagocytes: A Holistic Defense and Protection Against Active P2P Worms

    Chen, Ruichuan; Lua, Eng Keong; Crowcroft, Jon; Tang, Liyong; Chen, Zhong


    Active Peer-to-Peer (P2P) worms present serious threats to the global Internet by exploiting popular P2P applications to perform rapid topological self-propagation. Active P2P worms pose more deadly threats than normal scanning worms because they do not exhibit easily detectable anomalies, thus many existing defenses are no longer effective. We propose an immunity system with Phagocytes --- a small subset of elected P2P hosts that are immune with high probability and specialized in finding an...

  15. What Happened to P2P Systems? A Special Focus on Content Distribution Systems

    Mohammad Fawzi, Ali


    Peer-to-Peer (P2P) technology has emerged as a new distributed computing paradigm. P2P technology attempts to "harness the powers of the edges of the Internet" by making efficient and effective use of peers (users) at the "edge" of the Internet, by direct interaction between peers of the system. P2P architecture has witnessed lots of interest and research in the latest years because of the popularity of file-sharing applications based on it. Content distribution is an essential P2P applicati...

  16. Research on P2P Overlay Network Model with Small-world Features

    Liu, Hao; Chen, Zhigang


    Topology structure of P2P network decides its system performance. However, the existing P2P network models don’t take clustering and symmetry of nodes into account. Based on the algebra and graph theory method of Cayley graph, this paper proposes a novel P2P overlay network model with small-world features. Its simplicity and symmetry can ensure the self-organization and scalability of P2P network. The results of analysis and experiment shows that this model provides better robustness, h...

  17. Institute of Information Network Technology%P2P-SIP融合及P2P-SIP系统设计




  18. TCLM-P2P: Task Collaboration Logic Model Oriented to P2P Community%TCLM-P2P:面向P2P社区的任务协作逻辑模型

    王杨; 王汝传; 严远亭; 韩志杰; 赵保华


    P2P网络中广泛存在的“free riding”现象使其在任务协作领域的应用受到了极大制约.为了实现P2P网络环境下的有效任务协作,提出了一种具有激励机制的任务协作逻辑模型.基于Agent理论,首先给出了对等体、半对等体、P2P社区等概念;然后在合同网的框架下提出了面向P2P网络社区的任务协作逻辑模型TCLM-P2P(task collaborative logic model oriented to P2P community).相对于传统的任务协作模型,在合理的前提假设条件下,模型给出了模型公理和协作规则.该模型通过基于虚拟积分的协作算法实现了具有激励机制的P2P网络中的任务分配与协作.原型系统的实现及仿真实验结果表明TCLM-P2P模型具有可行性和有效性:不仅能够激励自利节点主动参与到任务分配与协作中;同时也能在一定程度上抑制节点的free riding行为,从而保障了P2P系统的有序工作.%Traditional P2P networks mainly are applied to file sharing and instant message fields. However, how to perform the task collaboration based on P2P community is a challenging job. The former research work indicated that the task collaboration in P2P network had been greatly restricted by free riding behaviors. To realize effective task allocating and task collaborating in P2P network environment, this paper presents a task collaboration logic model oriented to P2P community. Based on agent and multi-agent theory, the paper firstly introduces some concepts including the peer body, half-peer body and P2P community; then the TCLM-P2P is presented including some collaboration axioms and rulers. In order to enhance the incentive mechanism, virtual score becomes the main goal which each peer endeavor pursues. In addition, based on the contract net protocol, a task collaboration algorithm is presented. The proposed algorithm is composed of two phases. One is the task collaboration and the other is the task second bid when some peers fail

  19. 基于爬行器的大规模P2P IPTV测量%Crawler-Based Measurement of Large Scale P2P IPTV Systems 

    姜志宏; 王晖; 樊鹏翼


    为了解大规模P2P IPTV系统中的用户行为特征和拓扑结构特征等内在信息,开发和部署了一个多协议P2P IPTV爬行器TVCrawer,对3个主流的P2P IPTV系统--PPLive,PPStream和UUSee进行了大量的主动测量,并对P2P IPTV系统中的用户行为和网络拓扑特征进行了分析和比较.主要发现包括:1)P2P IPTV系统的频道在线人数中,有一半以上位于不可达的NAT或者防火墙后面;2)节点动态性的波动范围随频道人数的增加而增加,但是其取值范围具有幂律上限;3)节点会话长度符合广延指数分布;4)PPLive的入度分布属于具有指数截断的幂次分布,PPStream的入度表现为某种分段幂律函数,UUSee的入度接近威布尔分布;5)P2P IPTV系统都是异配网络;6)P2P IPTV系统都表现为小世界网络;7)PPLive网络具有聚类特征,而PPStream和UUSee则不存在明显聚类特征;8)3个系统都表现出类似于无标度网络的鲁棒性特征,而与其他两个系统比较时,PPLive具有更高的故障容错性和更明显的攻击脆弱性.这些测量研究和发现不仅有助于设计出更符合真实网络应用环境的系统或协议,也是实现对P2P IPTV进行监测,引导,控制等方面的重要依据和基础.%In order to gain insight on the topology characteristics of P2P IPTV systems and their online user behavior characteristics, This paper develop and deploys a multiprotocol P2P IPTV network crawler, called TVCrawler, which enables users to launch an in-depth measurement and comparative research for several well-known P2P IPTV systems, including PPLive, PPStream, and UUSee. This paper presents results from experiments and research efforts on these large-scale P2P IPTV overlay graphs. Major findings include 1) more than 50% of online users are unreachable because they lie behind NAT or firewall; 2) fluctuation range of churn increases with thc increase of the population of channel, and there exists a power-law upper bound for

  20. Phagocytes: A Holistic Defense and Protection Against Active P2P Worms

    Chen, Ruichuan; Crowcroft, Jon; Tang, Liyong; Chen, Zhong


    Active Peer-to-Peer (P2P) worms present serious threats to the global Internet by exploiting popular P2P applications to perform rapid topological self-propagation. Active P2P worms pose more deadly threats than normal scanning worms because they do not exhibit easily detectable anomalies, thus many existing defenses are no longer effective. We propose an immunity system with Phagocytes --- a small subset of elected P2P hosts that are immune with high probability and specialized in finding and "eating" worms in the P2P overlay. The Phagocytes will monitor their managed P2P hosts' connection patterns and traffic volume in an attempt to detect active P2P worm attacks. Once detected, local isolation, alert propagation and software patching will take place for containment. The Phagocytes further provide the access control and filtering mechanisms for communication establishment between the internal P2P overlay and the external hosts. We design a novel adaptive and interaction-based computational puzzle scheme at ...

  1. A Trust Scheme Based DRM Model for P2P System

    XIAO Shangqin; LU Zhengding; LING Hefei; ZOU Fuhao


    With the maturation of P2P technology, there are more and more challenges to the protection of digital rights.DRM for traditional Client/Server model can not satisfy the requirement of digital right protection of P2P network.With practical application of P2P network technology and new generational DRM technology, the article proposes a DRM model for P2P system based on trust degree.The proposed model shares the secret key to the trusty peers and affords necessary security ensure for digital content delivery based on P2P technology.Mathematic analyses and simulations show that, compared to the current DRM model, the proposed model is more robust toleration of transmit and security.

  2. Fuzzy-rule-based Adaptive Resource Control for Information Sharing in P2P Networks

    Wu, Zhengping; Wu, Hao

    With more and more peer-to-peer (P2P) technologies available for online collaboration and information sharing, people can launch more and more collaborative work in online social networks with friends, colleagues, and even strangers. Without face-to-face interactions, the question of who can be trusted and then share information with becomes a big concern of a user in these online social networks. This paper introduces an adaptive control service using fuzzy logic in preference definition for P2P information sharing control, and designs a novel decision-making mechanism using formal fuzzy rules and reasoning mechanisms adjusting P2P information sharing status following individual users' preferences. Applications of this adaptive control service into different information sharing environments show that this service can provide a convenient and accurate P2P information sharing control for individual users in P2P networks.

  3. A Free-Rider Forecasting Model Based on Gray System Theory in P2P Networks

    He Xu


    Full Text Available The aim of this study is to forecast the number of free-riders in P2P networks which can help network managers to know the status of the networks in advance and take appropriate measures to cope with free-riding behavior. Free-riding behavior is common in P2P networks, which has a negative impact on the robustness, availability and stability of the networks. Severe free-riding behavior may lead to the crash of the whole P2P application system. Based on the research of free-riding behavior in P2P networks, this paper constructs a free-rider forecasting model (GST model using Gray System Theory. Simulation experiments show that this model has high feasibility, and can carry out reasonable predictions on the number of free-riders in P2P networks.

  4. Computing and Routing for Trust in Structured P2P Network

    Biao Cai


    Full Text Available Study of trust in P2P network now is focus on how to effectively against various malicious behaviors such as providing fake or misleading feedback about other peers and the management of trust in a P2P environment. But the scotoma of portability that trust peer can join (leave a certain P2P network at anytime and anywhere is seldom discussed. In this paper, a structured topology for trusts management in portable P2P network based on DHT (discrete hash table is proposed first, in which includes trust management strategies and peer operations on certain DHT circle. After that, a novel trust-computing model for the structured P2P network and the main trust decisions in the structured network are introduced too. Effectiveness and practicality of the proposed trust management have been showed in simulation experiments at the end.

  5. Convergence of Internet and TV: The Commercial Viability of P2P Content Delivery

    de Boever, Jorn

    The popularity of (illegal) P2P (peer-to-peer) file sharing has a disruptive impact on Internet traffic and business models of content providers. In addition, several studies have found an increasing demand for bandwidth consuming content, such as video, on the Internet. Although P2P systems have been put forward as a scalable and inexpensive model to deliver such content, there has been relatively little economic analysis of the potentials and obstacles of P2P systems as a legal and commercial content distribution model. Many content providers encounter uncertainties regarding the adoption or rejection of P2P networks to spread content over the Internet. The recent launch of several commercial, legal P2P content distribution platforms increases the importance of an integrated analysis of the Strengths, Weaknesses, Opportunities and Threats (SWOT).

  6. Research on P2P Overlay Network Model with Small-world Features

    Hao LIU


    Full Text Available Topology structure of P2P network decides its system performance. However, the existing P2P network models don’t take clustering and symmetry of nodes into account. Based on the algebra and graph theory method of Cayley graph, this paper proposes a novel P2P overlay network model with small-world features. Its simplicity and symmetry can ensure the self-organization and scalability of P2P network. The results of analysis and experiment shows that this model provides better robustness, higher enquiry efficiency and better load balance than the existing P2P Overlay Network models such as Chord and CAN. Furthermore, it possesses the property of high clustering.

  7. Automated Simulation P2P Botnets Signature Detection by Rule-based Approach

    Raihana Syahirah Abdullah


    Full Text Available Internet is a most salient services in communication. Thus, companies take this opportunity by putting critical resources online for effective business organization. This has given rise to activities of cyber criminals actuated by botnets. P2P networks had gained popularity through distributed applications such as file-sharing, web caching and network storage whereby it is not easy to guarantee that the file exchanged not the malicious in non-centralized authority of P2P networks. For this reason, these networks become the suitable venue for malicious software to spread. It is straightforward for attackers to target the vulnerable hosts in existing P2P networks as bot candidates and build their zombie army. They can be used to compromise a host and make it become a P2P bot. In order to detect these botnets, a complete flow analysis is necessary. In this paper, we proposed an automated P2P botnets through rule-based detection approach which currently focuses on P2P signature illumination. We consider both of synchronisation within a botnets and the malicious behaviour each bot exhibits at the host or network level to recognize the signature and activities in P2P botnets traffic. The rule-based approach have high detection accuracy and low false positive.

  8. Bandwidth Reduction via Localized Peer-to-Peer (P2P Video

    Ken Kerpez


    Full Text Available This paper presents recent research into P2P distribution of video that can be highly localized, preferably sharing content among users on the same access network and Central Office (CO. Models of video demand and localized P2P serving areas are presented. Detailed simulations of passive optical networks (PON are run, and these generate statistics of P2P video localization. Next-Generation PON (NG-PON is shown to fully enable P2P video localization, but the lower rates of Gigabit-PON (GPON restrict performance. Results here show that nearly all of the traffic volume of unicast video could be delivered via localized P2P. Strong growth in video delivery via localized P2P could lower overall future aggregation and core network bandwidth of IP video traffic by 58.2%, and total consumer Internet traffic by 43.5%. This assumes aggressive adoption of technologies and business practices that enable highly localized P2P video.

  9. P2 P 网络借贷的运营与法律监管%Regulation on Online P2P Lending



    The rapid development of online person -to -person lending poses great challenge to its regula-tion.In the United States ,the current regulatory structure for online P 2 P lending involves multiple overseeing agen-cies including the United States Securities and Exchange Commission , various federal bank regulators , the Consum-er Financial Protection Bureau and the state counterparts of all these entities .Under this system , the protection on lenders mainly depends on the securities regulation .From April 2014, P2P lending came under the regulatory man-date of the Financial Conduct Authority.Our country hasn’t started regulation on online P2P lending.Due to the public interests it involves , the necessity for online P2P lending to prevent risk and develop healthily requires its regulation as soon as possible .The sphere of online P2P lending is similar to financial business , so it should be regulated by financial regulatory agency .Under the current financial regulation system in China ,banking regulatory commission should be the authority to regulate on online P 2P lending.%P2P网络借贷的迅猛发展给监管带来了巨大的挑战。在美国,P2P网络借贷实行由证券监管部门、银行监管部门、金融消费者保护局等多个部门共同监管的分散监管体制,对投资者的保护主要是通过证券监管实现的。英国自2014年4月起将P2P网络借贷纳入金融行为局( FCA)的监管范畴。我国尚未对P2P网络借贷予以监管,但P2P行业因涉及公众利益,出于风险防范和其健康发展的需要,监管问题必须尽快予以解决。由于P2 P借贷公司从事的是类金融业务,故应由监管金融业务的机构予以监管。在我国现行的金融监管体制下,对P2 P网络借贷实行统一监管的机构应为银监会。

  10. A Simple FSPN Model of P2P Live Video Streaming System

    Kotevski, Zoran; Mitrevski, Pece


    Peer to Peer (P2P) live streaming is relatively new paradigm that aims at streaming live video to large number of clients at low cost. Many such applications already exist in the market, but, prior to creating such system it is necessary to analyze its performance via representative model that can provide good insight in the system’s behavior. Modeling and performance analysis of P2P live video streaming systems is challenging task which requires addressing many properties and issues of P2P s...

  11. Mobility Impact in Initializing Ring-Based P2P Systems over MANETs

    Wei Ding


    Full Text Available With the encouragement from success of P2P systems in real world application, recently we have seen active research on synergy of P2P systems and mobile ad hoc networks. The paper proposes a solution for mobility disturbance problem in initialization of ring-based P2P systems over ad hoc networks. It is a decentralized ring construction protocol in presence of mobility. A Mobile Ring Ad-hoc Networks (MRAN protocol is presented. MRAN is an extension of RAN [1] under the mobile condition. Simulation result shows MRAN works well with mobility. Upper bound of maximum speed of moving nodes is investigated in simulation.

  12. Pre-Paid Charging System for Sip-P2P Commercial Applications

    Damian Nowak


    Full Text Available The new SIP-P2P approach brings many advantages like the improved reliability and the ease of setup.However, Communications Service Providers (CSPs offering VoIP services seem to be afraid to losetheir profits due to the introduction of SIP-P2P. Claimed is the lack of session establishment controlleading to revenue leakages. In this work we introduce a charging system for SIP-P2P that assures CSPs’revenue from using SIP-based peer-to-peer communications commercially. The proposed solutionconsists of a new “carrier-grade P2P network” concept, software modification of existing equipment andgives some charging application design guidelines. An application prototype was implemented toexamine the concept. Additionally, experiments were done to provide the methodology for systemdimensioning.

  13. Locating Highly Connected Nodes in P2P Networks with Heterogeneous Structures

    ZHANG Haoxiang; ZHANG Lin; SHAN Xiuming; Victor O. K. LI


    Peer-to-peer (P2P) networks aggregate enormous storage and processing resources while mini-mizing entry and scaling costs. Gnutella-like P2P networks are complex heterogeneous networks, in which the underlying overlay topology has a power-law node degree distribution. While scale-free networks have great robustness against random failures, they are vulnerable to deliberate attacks where highly connected nodes are eliminated. Since high degree nodes play an important role in maintaining the connectivity, this paper presents an algorithm based on random walks to locate high degree nodes in P2P networks. Simula-tions demonstrate that the algorithm performs well in various scenarios and that heterogeneous P2P net-works are very sensitive to deliberate attacks.

  14. CHC: A Robust P2P Overlay Network with Simple Routing and Small-World Features

    Wenjun Xiao


    Full Text Available Almost all recent researches on P2P systems focus on howto build a highly usable P2P overlay network. Researchersinclude small routing table, short query path and goodrobustness into their design objectives of overlay topology. Inthis paper, we present a general group theory method anddefine a new Cayley graph. Based on this Cayley graph, wepropose a novel P2P overlay network called CHC, which hassimple routing (searching scheme and many other excellentproperties such as short query path, high clustering and goodrobustness because of its symmetry. The performance isevaluated by simulation to show that CHC possesses shorterquery path length and higher clustering and better robustnessthan several popular P2P overlay networks such as Chord andUlysses.

  15. A Local Scalable Distributed EM Algorithm for Large P2P Networks

    National Aeronautics and Space Administration — his paper describes a local and distributed expectation maximization algorithm for learning parameters of Gaussian mixture models (GMM) in large peer-to-peer (P2P)...

  16. Secure Mobile Agent for Telemedicine Based on P2P Networks

    Hsu, Wen-Shin; Pan, Jiann-I


    Exploring intelligent mobile agent (MA) technology for assisting medical services or transmitting personal patient-health information in telemedicine applications has been widely investigated. Conversely, peer-to-peer (P2P) networking has become one of the most popular applications used in the Internet because of its benefits for easy-to-manage resources and because it balances workloads. Therefore, constructing an agent-based telemedicine platform based on P2P networking architecture is nece...

  17. An Efficient, Scalable and Robust P2P Overlay for Autonomic Communication

    Li, Deng; Liu, Hui; Vasilakos, Athanasios

    The term Autonomic Communication (AC) refers to self-managing systems which are capable of supporting self-configuration, self-healing and self-optimization. However, information reflection and collection, lack of centralized control, non-cooperation and so on are just some of the challenges within AC systems. Since many self-* properties (e.g. selfconfiguration, self-optimization, self-healing, and self-protecting) are achieved by a group of autonomous entities that coordinate in a peer-to-peer (P2P) fashion, it has opened the door to migrating research techniques from P2P systems. P2P's meaning can be better understood with a set of key characteristics similar to AC: Decentralized organization, Self-organizing nature (i.e. adaptability), Resource sharing and aggregation, and Fault-tolerance. However, not all P2P systems are compatible with AC. Unstructured systems are designed more specifically than structured systems for the heterogeneous Internet environment, where the nodes' persistence and availability are not guaranteed. Motivated by the challenges in AC and based on comprehensive analysis of popular P2P applications, three correlative standards for evaluating the compatibility of a P2P system with AC are presented in this chapter. According to these standards, a novel Efficient, Scalable and Robust (ESR) P2P overlay is proposed. Differing from current structured and unstructured, or meshed and tree-like P2P overlay, the ESR is a whole new three dimensional structure to improve the efficiency of routing, while information exchanges take in immediate neighbors with local information to make the system scalable and fault-tolerant. Furthermore, rather than a complex game theory or incentive mechanism, asimple but effective punish mechanism has been presented based on a new ID structure which can guarantee the continuity of each node's record in order to discourage negative behavior on an autonomous environment as AC.

  18. P2P network traffic control mechanism based on global evaluation values

    XU Xiao-long; WANG Ru-chuan


    Peer-to-peer (P2P) computing technology has been widely used on the Internet to exchange data. However, it occupies much network bandwidth, and thus greatly influences traditional business on the Interact. Besides, problems about free-riders and 'tragedy of the commons' in the P2P environment estrange from it P2P users who constantly contribute to the network with quality resources. This article proposes a new P2P network traffic control mechanism based on global evaluation values. It aims to help individual users to avoid peak traffic time as much as possible, ease network congestion and protect traditional business on the Interact, as well as differentiating priority grades of peers according to their contributions and stimulating them to share their valuable resources actively. This article first analyzes the current state of network traffic, and then elaborates on P2P network traffic control policies and proposes the peer's priority level differentiation mechanism based on global evaluation values. Finally,after the testing results and analysis of the proposed P2P network traffic control mechanism are discussed, conclusions are drawn.

  19. Fine-grained P2P traffc classifi cation by simply counting flows

    Jie HE; Yue-xiang YANG; Yong QIAO; Wen-ping DENG


    The continuous emerging of peer-to-peer (P2P) applications enriches resource sharing by networks, but it also brings about many challenges to network management. Therefore, P2P applications monitoring, in particular, P2P traffic classifi cation, is becoming increasingly important. In this paper, we propose a novel approach for accurate P2P traffic classifi cation at a fi ne-grained level. Our approach relies only on counting some special fl ows that are appearing frequently and steadily in the traffic generated by specifi c P2P applications. In contrast to existing methods, the main contribution of our approach can be summarized as the following two aspects. Firstly, it can achieve a high classifi cation accuracy by exploiting only several generic properties of fl ows rather than complicated features and sophisticated techniques. Secondly, it can work well even if the classifi cation target is running with other high bandwidth-consuming applications, outperforming most existing host-based approaches, which are incapable of dealing with this situation. We evaluated the performance of our approach on a real-world trace. Experimental results show that P2P applications can be classifi ed with a true positive rate higher than 97.22%and a false positive rate lower than 2.78%.

  20. Strategies for P2P connectivity in reconfigurable converged wired/wireless access networks.

    Puerto, Gustavo; Mora, José; Ortega, Beatriz; Capmany, José


    This paper presents different strategies to define the architecture of a Radio-Over-Fiber (RoF) Access networks enabling Peer-to-Peer (P2P) functionalities. The architectures fully exploit the flexibility of a wavelength router based on the feedback configuration of an Arrayed Waveguide Grating (AWG) and an optical switch to broadcast P2P services among diverse infrastructures featuring dynamic channel allocation and enabling an optical platform for 3G and beyond wireless backhaul requirements. The first architecture incorporates a tunable laser to generate a dedicated wavelength for P2P purposes and the second architecture takes advantage of reused wavelengths to enable the P2P connectivity among Optical Network Units (ONUs) or Base Stations (BS). While these two approaches allow the P2P connectivity in a one at a time basis (1:1), the third architecture enables the broadcasting of P2P sessions among different ONUs or BSs at the same time (1:M). Experimental assessment of the proposed architecture shows approximately 0.6% Error Vector Magnitude (EVM) degradation for wireless services and 1 dB penalty in average for 1 x 10(-12) Bit Error Rate (BER) for wired baseband services.

  1. Monitoring and Resource Management in P2P Grid-Based Web Services

    Djafri Laouni


    Full Text Available Grid computing has recently emerged as a response to the growing demand for resources (processing power, storage, etc. exhibited by scientific applications. However, as grid sizes increase, the need for self-organization and dynamic reconfigurations is becoming more and more important. Since such properties are exhibited by P2P systems, the convergence of grid computing and P2P computing seems natural. However, using P2P systems (usually running on the Internet on a grid infrastructure (generally available as a federation of SAN-based clusters interconnected by high-bandwidth WANs may raise the issue of the adequacy of the P2P communication mechanisms. Among the interesting properties of P2P systems is the  volatility of  peers  which  causes  the  need  for  integration  of  a  service fault tolerance. And service Load balancing,   As a solution, we proposed a mechanism of fault tolerance and model of Load balancing  adapted to a grid P2P model, named SGRTE (Monitoring and Resource Management, Fault Tolerances and Load Balancing.

  2. P2P-based botnets: structural analysis, monitoring, and mitigation

    Yan, Guanhua [Los Alamos National Laboratory; Eidenbenz, Stephan [Los Alamos National Laboratory; Ha, Duc T [UNIV AT BUFFALO; Ngo, Hung Q [UNIV AT BUFFALO


    Botnets, which are networks of compromised machines that are controlled by one or a group of attackers, have emerged as one of the most serious security threats on the Internet. With an army of bots at the scale of tens of thousands of hosts or even as large as 1.5 million PCs, the computational power of botnets can be leveraged to launch large-scale DDoS (Distributed Denial of Service) attacks, sending spamming emails, stealing identities and financial information, etc. As detection and mitigation techniques against botnets have been stepped up in recent years, attackers are also constantly improving their strategies to operate these botnets. The first generation of botnets typically employ IRC (Internet Relay Chat) channels as their command and control (C&C) centers. Though simple and easy to deploy, the centralized C&C mechanism of such botnets has made them prone to being detected and disabled. Against this backdrop, peer-to-peer (P2P) based botnets have emerged as a new generation of botnets which can conceal their C&C communication. Recently, P2P networks have emerged as a covert communication platform for malicious programs known as bots. As popular distributed systems, they allow bots to communicate easily while protecting the botmaster from being discovered. Existing work on P2P-based hotnets mainly focuses on measurement of botnet sizes. In this work, through simulation, we study extensively the structure of P2P networks running Kademlia, one of a few widely used P2P protocols in practice. Our simulation testbed incorporates the actual code of a real Kademlia client software to achieve great realism, and distributed event-driven simulation techniques to achieve high scalability. Using this testbed, we analyze the scaling, reachability, clustering, and centrality properties of P2P-based botnets from a graph-theoretical perspective. We further demonstrate experimentally and theoretically that monitoring bot activities in a P2P network is difficult


    Liu Hui; Huang Yongfeng; Li Xing


    The rapid development of Internet has led to the explosion of information sharing, and how to supervise the sharing is a main research topic on current Internet. Aiming at the disadvantage that the current Peer-to-Peer (P2P) is hard to manage and control, this paper presents a Session Initial Protocol (SIP)-based P2P network of three-level architecture. SIP middleware is introduced to the middle level of the three-layer architecture. By the connection function of the SIP signaling, the P2P transmission on media-level can be controlled. Using SIP's register and authentication function, the manage layer can manage the whole P2P network. Based on the aforementioned architecture, this paper investigates the grouping strategy on a live broadcast application in P2P network. Combined with the function of SIP register, the paper works on several grouping strategies, sets up models to manage users by grouping them, presents a weight-based K-means IP address grouping algorithm, and realizes it. The experiment shows that the grouping strategy presented in this paper can solve the problem of group sharing of network resource, and can realize the efficient-sharing, reasonable-distributing of network resource.

  4. Secure mobile agent for telemedicine based on P2P networks.

    Hsu, Wen-Shin; Pan, Jiann-I


    Exploring intelligent mobile agent (MA) technology for assisting medical services or transmitting personal patient-health information in telemedicine applications has been widely investigated. Conversely, peer-to-peer (P2P) networking has become one of the most popular applications used in the Internet because of its benefits for easy-to-manage resources and because it balances workloads. Therefore, constructing an agent-based telemedicine platform based on P2P networking architecture is necessary. The main purpose of this paper is to construct a safe agent-based telemedicine that based on P2P networking architecture. Two themes are addressed in this paper: (a) the P2P network architecture for an agent-based telemedicine service, and (b) the security mechanisms for the proposed telemedicine networking architecture. When an MA contains patient information and migrates from one host to another through the Internet, it can be attacked by other software agents or agent platforms that can illegally access patient information. The proposed P2P network architecture is based on the JXTA protocol and provides two types of telemedicine service models: the predictable service model and unpredictable service model. This architecture employs a two-layer safety mechanism for MAs (i.e., time-limited black boxes and RSA undetachable signature technologies), to provide a secure solution for agent-based telemedicine services.

  5. P2P Streaming Traffic Classification in High-Speed Networks

    Chen Luying; Cong Rong; Yang Jie; Yu Hua


    The growing P2P streaming traffic brings a variety of problems and challenges to ISP networks and service providers.A P2P streaming traffic classification method based on sampling technology is presented in this paper.By analyzing traffic statistical features and network behavior of P2P streaming,a group of flow characteristics were found,which can make P2P streaming more recognizable among other applications.Attributes from Netflow and those proposed by us are compared in terms of classification accuracy,and so are the results of different sampling rates.It is proved that the unified classification model with the proposed attributes can identify P2P streaming quickly and efficiently in the online system.Even with 1∶50 sampling rate,the recognition accuracy can be higher than 94%.Moreover,we have evaluated the CPU resources,storage capacity and time consumption before and after the sampling,it is shown that the classification model after the sampling can significantly reduce the resource requirements with the same recognition accuracy.

  6. An Efficient Architecture for Information Retrieval in P2P Context Using Hypergraph

    Ismail, Anis; Durand, Nicolas; Hajjar, Mohammad


    Peer-to-peer (P2P) Data-sharing systems now generate a significant portion of Internet traffic. P2P systems have emerged as an accepted way to share enormous volumes of data. Needs for widely distributed information systems supporting virtual organizations have given rise to a new category of P2P systems called schema-based. In such systems each peer is a database management system in itself, ex-posing its own schema. In such a setting, the main objective is the efficient search across peer databases by processing each incoming query without overly consuming bandwidth. The usability of these systems depends on successful techniques to find and retrieve data; however, efficient and effective routing of content-based queries is an emerging problem in P2P networks. This work was attended as an attempt to motivate the use of mining algorithms in the P2P context may improve the significantly the efficiency of such methods. Our proposed method based respectively on combination of clustering with hypergraphs. We use...

  7. Using the Reputation Score Management for Constructing Fair P2P File Sharing System

    Jun Han


    Full Text Available This paper has used the reputation score management for constructing a fair P2P file sharing system, the system design principle is simple and easy to realize, and every node entering into the P2P network obtains a certain reputation score, and obtains the corresponding resources reward according to the score. This paper has described the fair sharing strategies facing node network bandwidth and TTL, and these strategies can be used independently or be combined with other reputation score managements of P2P network. These two strategies have been discussed in the specific reputation score management system of P2P network Eigen Trust, and the test results indicate that: compared with a common P2P network, the fair sharing strategies of this paper have faster file download speed and can decrease the network message communication amount during the process looking for resources. It can also be combined with another reputation management system. it is simple and easy to be realized, its main purposes are to fairly share network bandwidth and to decrease information communication volume, and it can suppress the free riding behavior to some extent.

  8. Information Exchange rather than Topology Awareness: Cooperation between P2P Overlay and Traffic Engineering

    Jia Zhao


    Full Text Available Solutions to the routing strategic conflict between noncooperative P2P overlay and ISP underlay go separate ways: hyperselfishness and cooperation. Unpredictable (possibly adverse impact of the hyperselfish topology awareness, which is adopted in both overlay routing and traffic engineering, has not been sufficiently studied in the literature. Topology-related information exchange in a cooperatively efficient way should be highlighted to alleviate the cross-layer conflict. In this paper, we first illustrate the hyperselfish weakness with two dynamic noncooperative game models in which hyperselfish overlay or underlay has to accept a suboptimal profit. Then we build a synergistic cost-saving (SC game model to reduce the negative effects of noncooperation. In the SC model, through information exchange, that is, the classified path-delay metrics for P2P overlay and peer locations for underlay, P2P overlay selects proximity as well as saving traffic transit cost for underlay, and ISP underlay adjusts routing to optimize network cost as well as indicating short delay paths for P2P. Simulations based on the real and generated topologies validate cost improvement by SC model and find a proper remote threshold value to limit P2P traffic from remote area, cross-AS, or cross-ISP.

  9. 基于 P2P 网络的 Bitcoin 虚拟货币分析%Bitcoin Virtual Currency Analysis Based on P2P

    石苗; 李宥谋


    Bitcoin 是一种基于 P2P 网络的匿名数字货币,论文从网络虚拟货币的发展现状出发,从技术层面详细分析Bitcoin 形成相关技术原理及其交易过程和验证机制,肯定了其历史性和革命性。同时分析 Bitcoin 存在的各方面问题,探究其在网络虚拟货币统一方面的重要借鉴意义。%Bitcoin is an anonymous digital cash based on P2P network .In this paper ,starting from the development present situation of the network virtual currency ,detailed analysis formation related technical principles and transaction process and the authentication mechanism from the technical level of Bitcoin ,affirmed its historical and revolutionary .At the same time ,aspects of problems of Bitcoin are analyzed ,its importance in the network virtual currency unification is explored .

  10. P2P Lending Risk Contagion Analysis Based on a Complex Network Model

    Qi Wei


    Full Text Available This paper analyzes two major channels of P2P lending risk contagion in China—direct risk contagion between platforms and indirect risk contagion with other financial organizations as the contagion medium. Based on this analysis, the current study constructs a complex network model of P2P lending risk contagion in China and performs dynamics analogue simulations in order to analyze general characteristics of direct risk contagion among China’s online P2P lending platforms. The assumed conditions are that other financial organizations act as the contagion medium, with variations in the risk contagion characteristics set under the condition of significant information asymmetry in Internet lending. It is indicated that, compared to direct risk contagion among platforms, both financial organizations acting as the contagion medium and information asymmetry magnify the effect of risk contagion. It is also found that the superposition of media effects and information asymmetry is more likely to magnify the risk contagion effect.

  11. 11th International Conference on P2P, Parallel, Grid, Cloud and Internet Computing

    Barolli, Leonard; Amato, Flora


    P2P, Grid, Cloud and Internet computing technologies have been very fast established as breakthrough paradigms for solving complex problems by enabling aggregation and sharing of an increasing variety of distributed computational resources at large scale. The aim of this volume is to provide latest research findings, innovative research results, methods and development techniques from both theoretical and practical perspectives related to P2P, Grid, Cloud and Internet computing as well as to reveal synergies among such large scale computing paradigms. This proceedings volume presents the results of the 11th International Conference on P2P, Parallel, Grid, Cloud And Internet Computing (3PGCIC-2016), held November 5-7, 2016, at Soonchunhyang University, Asan, Korea.

  12. Analytical Modelling of Localized P2P Streaming Systems under NAT Consideration

    Mohammad Z. M. Masoud


    Full Text Available NAT has been design to work with Internet client-server structure. The emerged of Peer-to-Peer (P2Pnetworks and applications revealed the incompatibility between P2P applications and NAT. Many methodshas been developed and implemented to solve connectivity between peers behind NAT devices.Nevertheless, various NATing types can’t communicate with one another. In this work, we are going tostudy the impact of NAT types on the start-up delay time of peers in P2P streaming systems. We willdemonstrate the ability of NATing to expel peers in P2P live streaming systems. A new neighbour selectingalgorithm will be proposed. This algorithm will utilize NAT-types configurations as a parameter. We haveutilized NS2 simulator to show the performance of the new algorithm in increasing the connectivity,reducing the number of expelled peers and implementing of locality.

  13. A New Caching Technique to Support Conjunctive Queries in P2P DHT

    Kobatake, Koji; Tagashira, Shigeaki; Fujita, Satoshi

    P2P DHT (Peer-to-Peer Distributed Hash Table) is one of typical techniques for realizing an efficient management of shared resources distributed over a network and a keyword search over such networks in a fully distributed manner. In this paper, we propose a new method for supporting conjunctive queries in P2P DHT. The basic idea of the proposed technique is to share a global information on past trials by conducting a local caching of search results for conjunctive queries and by registering the fact to the global DHT. Such a result caching is expected to significantly reduce the amount of transmitted data compared with conventional schemes. The effect of the proposed method is experimentally evaluated by simulation. The result of experiments indicates that by using the proposed method, the amount of returned data is reduced by 60% compared with conventional P2P DHT which does not support conjunctive queries.

  14. Public Key Cryptosystem Approach for P2P Botnet Detection and Prevention

    Anas Aliyu Usman


    Full Text Available Distributed (P2P botnets have as of late been received by botmasters for their versatility against take-down endeavors. Other than being harder to bring down, p2p botnets tend to be stealthier in the way they perform vindictive exercises, making current discovery approaches ineffectual. In this paper, we simulate our proposal by detecting a gray hole attack in an Ad Hoc network using NS2.The detected malicious node is listed in a black hole list and notices all other nodes in the network to stop communicating with them. Our botnet location framework has been equipped for identifying stealthy P2P botnets (Gray Hole nodes and can reduce packet loss caused by malicious nodes and have a better packet delivery ratio (PDR within less period of time.

  15. On the Design and Implementation of Structured P2P VPNs

    Wolinsky, David Isaac; Lee, Kyungyong; Liu, Yonggang; Xu, Jiangyan; Boykin, P Oscar; Figueiredo, Renato


    Centralized Virtual Private Networks (VPNs) when used in distributed systems have performance constraints as all traffic must traverse through a central server. In recent years, there has been a paradigm shift towards the use of P2P in VPNs to alleviate pressure placed upon the central server by allowing participants to communicate directly with each other, relegating the server to handling session management and supporting NAT traversal using relays when necessary. Another, less common, approach uses unstructured P2P systems to remove all centralization from the VPN. These approaches currently lack the depth in security options provided by other VPN solutions, and their scalability constraints have not been well studied. In this paper, we propose and implement a novel VPN architecture, which uses a structured P2P system for peer discovery, session management, NAT traversal, and autonomic relay selection and a central server as a partially-automated public key infrastructure (PKI) via a user-friendly web inte...

  16. A P2P Botnet Virus Detection System Based on Data-Mining Algorithms

    Wernhuar Tarng


    Full Text Available A P2P botnet virus detection system based on data-mining algorithms is proposed in this study to detect theinfected computers quickly using Bayes Classifier and Neural Network (NN Classifier. The system candetect P2P botnet viruses in the early stage of infection and report to network managers to avoid furtherinfection. The system adopts real-time flow identification techniques to detect traffic flows produced by P2Papplication programs and botnet viruses by comparing with the known flow patterns in the database. Aftertrained by adjusting the system parameters using test samples, the experimental results show that theaccuracy of Bayes Classifier is 95.78% and that of NN Classifier is 98.71% in detecting P2P botnet virusesand suspected flows to achieve the goal of infection control in a short time.

  17. P2PRPIPS: A P2P and Reverse Proxy Based Web Intrusion Protection System

    Qian He


    Full Text Available In order to protect web sites with various program languages and high throughput efficiently, a web Intrusion Protection System (IPS based on P2P and reverse proxy architecture was designed and implemented. The P2P based web intrusion protection system has multi web firewall nodes and nodes with same program cooperate with each other under P2P architecture. Some nodes work as net flow allocator and some work as detector and they can convert to each other according to the requirements dynamically. The WAF program has the characteristics of session keeping and load balancing and it can detect messages by using expert library and many plug-in components. The technology of reverse proxy is used for response the web request. Experiments show that the system can effectively prevent attacks form application layer. It is proved more efficient and stable than single node.

  18. Supporting K nearest neighbors query on high-dimensional data in P2P systems

    Mei LI; Wang-Chien LEE; Anand SIVASUBRAMANIAM; Jizhong ZHAO


    Peer-to-peer systems have been widely used for sharing and exchanging data and resources among numerous computer nodes.Various data objects identifiable with high dimensional feature vectors,such as text,images,genome sequences,are starting to leverage P2P technology.Most of the existing works have been focusing on queries on data objects with one or few attributes and thus are not applicable on high dimensional data objects.In this study,we investigate K nearest neighbors query (KNN)on high dimensional data objects in P2P systems.Efficient query algorithm and solutions that address various technical challenges raised by high dimensionality,such as search space resolution and incremental search space refinement,are proposed.An extensive simulation using both synthetic and real data sets demonstrates that our proposal efficiently supports KNN query on high dimensional data in P2P systems.

  19. Relay Ability Estimation and Topology Control Using Multidimensional Context Parameters for Mobile P2P Multicast

    Kubo Hiroyuki


    Full Text Available We focus on mobile P2P multicast, in which mobile end nodes not only act as receivers but also relay the received stream forward to others. In mobile P2P multicast, negative effects caused by the change of available bandwidth and the disconnection of mobile nodes are propagated to the downstream nodes. To solve this problem, we developed a novel node-allocation framework using the multidimensional context parameters of each mobile node, which include available bandwidth, disconnection rate, and the remaining battery capacity. Considering the significance of each parameter, our method integrates these parameters into a single parameter called relay ability. Taking the relay ability into account, each node is allocated to the multicast topology to minimize the negative effects mentioned above. To test our method, we applied our framework to conventional P2P multicast topology and show the results from comparative evaluations through computer simulation.

  20. Distributed Algorithms for Improving Search Efficiency in P2P Overlays

    Chittaranjan Hota


    Full Text Available Peer-to-peer (P2P overlay is a distributed application architecture in which peers share their resources. Peers are equally privileged, equipotent participants in the application. Several algorithms for enhancing P2P file searching have been proposed in the literature. In this paper, we have proposed a unique approach of reducing the P2P search complexity and improving search efficiency by using distributed algorithms. In our approach a peer mounts other popular peer’s files and also replicates other popular files or critical files identified using a threshold value. Once a file is mounted, file access requests can be serviced by transparently retrieving the file and sending it to the requesting peer. Replication used in this work improves the file retrieval time by allowing parallel transfer. We have shown the performance analysis of our proposed approach which shows improvement in the search efficiency.

  1. Efficient content-based P2P image retrieval using peer content descriptions

    Muller, Wolfgang T.; Eisenhardt, Martin; Henrich, Andreas


    Peer-to-peer (P2P) networks are overlay networks that connect independent computers (also called nodes or peers). In contrast to client/server solutions, all nodes offer and request services from other peers in a P2P network. P2P networks are very attractive in that they harness the computing power of many common desktop machines and necessitate little administrative overhead. While the resulting computing power is impressive, efficiently looking up data still is the major challenge in P2P networks. Current work comprises fast lookup of one-dimensional values (Distributed Hash Tables, DHT) and retrieval of texts using few keywords. However, the lookup of multimedia data in P2P networks is still attacked by very few groups. In this paper, we present experiments with efficient Content Based Image Retrieval in a P2P environment, thus a P2P-CBIR system. The challenge in such systems is to limit the number of messages sent, and to maximize the usefulness of each peer contacted in the query process. We achieve this by distributing peer data summaries over the network. Obviously, the data summaries have to be compact in order to limit the communication overhead. We propose an CBIR scheme based on a compact peer data summary. This peer data summary relies on cluster frequencies. To obtain the compact representation of a peer's collection, a global clustering of the data is efficiently calculated in a distributed manner. After that, each peer publishes how many of its images fall into each cluster. These cluster frequencies are then used by the querying peer to contact only those peers that have the largest number of images present in one cluster given by the query. In our paper we further detail the various challenges that have to be met by the designers of such a P2P-CBIR, and we present experiments with varying degree of data replication (duplicates of images), as well as quality of clustering within the network.

  2. Integrating XQuery and P2P in MonetDB/XQuery*

    Zhang, Ying; Boncz, Peter; Arenas, M; Hidders, J.


    MonetDB/XQuery* is a fully functional publicly available XML DBMS that has been extended with distributed and P2P data management functionality. Our (minimal) XQuery language extension XRPC adds the concept of RPC to XQuery, and exploits the set-at-a-time database processing model to optimize the networking cost through a technique called Bulk RPC. We describe our approach to include the services offered by diverse P2P network structures (such as DHTs), in a way that avoids any further intrus...

  3. Cross-layer P2P traffic engineering in content-based networks.

    Zhang, Xu


    Peer-to-peer (P2P) content sharing applications account for a significant fraction of the traffic volumes and is expected to increase [1]. Data is distributed to a large population of end client peers from end source peers in P2P systems, without the need for big investments to deploy servers. The costs of the content distribution are thus shared among end users and Internet service providers (ISPs). Consequently, negative impacts, such as increased inter-ISP traffic in particular, have becom...

  4. A Hybrid P2P Approach to Service Discovery in the Cloud

    Nor Aniza Abdullah


    Full Text Available Highly scalable techniques for service discovery are key to the efficient use of Cloud resources, since the Cloud computing appears to be part of the mainstream computing in a few years. We embarked on a preliminary study on Cloud service discovery by adopting an unstructured P2P paradigm. We developed an efficient mechanism for routing of service requests by coupling a number of components: one-hop replication, semanticaware message routing, topology reorganization, and supernodes. A number of experiments were carried out that demonstrated the expected performance of the proposed P2P search scheme.

  5. Enabling Co-located Learning over Mobile Ad Hoc P2P with LightPeers

    Christensen, Bent Guldbjerg; Kristensen, Mads Darø; Hansen, Frank Allan


    This paper presents LightPeers – a new mobile P2P framework specifically tailored for use in a nomadic learning environment. A set of key requirements for the framework is identified based on nomadic learning, and these requirements are used as outset for designing and implementing the architecture...... and protocols. The main contributions of the LightPeers framework are: a mobile P2P framework including a specialized robust messaging protocol resilient to changes in the network topology, an developers API, and a suite of LightPeers applications supporting nomadic learning prototyping key features of LightPeers....

  6. A Participation-Based Trust Model for Mobile P2P Networks

    Kai Liu


    Full Text Available Mobile peer-to-peer (P2P networks have become increasingly popular, but the attacks and selfness of peers make it vulnerable. In this paper, a trust model based on participation is proposed for mobile P2P networks (called ParticipationTrust. It could deal with the egoistic and malicious behaviors. And the level of peer’s participation could be calculated through the transaction participation and recommendation participation. A set of experiments show that the model is rational and effective

  7. Cluster based hierarchical resource searching model in P2P network

    Yang Ruijuan; Liu Jian; Tian Jingwen


    For the problem of large network load generated by the Gnutella resource-searching model in Peer to Peer (P2P) network, a improved model to decrease the network expense is proposed, which establishes a duster in P2P network,auto-organizes logical layers, and applies a hybrid mechanism of directional searching and flooding. The performance analysis and simulation results show that the proposed hierarchical searching model has availably reduced the generated message load and that its searching-response time performance is as fairly good as that of the Gnutella model.

  8. Comparing manually-developed and data-driven rules for P2P learning

    Loots, L


    Full Text Available Phoneme-to-phoneme (P2P) learning provides a mechanism for predicting the pronunciation of a word based on its pronunciation in a different accent, dialect or language. The authors evaluate the effectiveness of manually-developed as well...

  9. Database selection and result merging in P2P web search

    Chernov, S.; Serdyukov, P.; Bender, M.; Michel, S.; Weikum, G.; Zimmer, C.


    Intelligent Web search engines are extremely popular now. Currently, only the commercial centralized search engines like Google can process terabytes of Web data. Alternative search engines fulfilling collaborative Web search on a voluntary basis are usually based on a blooming Peer-to-Peer (P2P) te

  10. Scaling laws for file dissemination in P2P networks with random contacts

    Núñez-Queija, R.; Prabhu, B.


    In this paper we obtain the scaling law for the mean broadcast time of a file in a P2P network with an initial population of N nodes. In the model, at Poisson rate lambda a node initiates a contact with another node chosen uniformly at random. This contact is said to be successful if the contacted n

  11. Extending an Afrikaans pronunciation dictionary using Dutch resources and P2P/GP2P

    Loots, L


    Full Text Available . This is compared to the more common approach of extending the Afrikaans dictionary by means of graphemeto-phoneme (G2P) conversion. The results indicate that the Afrikaans pronunciations obtained by P2P and GP2P from the Dutch dictionary are more accurate than...

  12. XQ2P: Efficient XQuery P2P Time Series Processing

    Butnaru, Bogdan; Gardarin, Georges; Yeh, Laurent


    In this demonstration, we propose a model for the management of XML time series (TS), using the new XQuery 1.1 window operator. We argue that centralized computation is slow, and demonstrate XQ2P, our prototype of efficient XQuery P2P TS computation in the context of financial analysis of large data sets (>1M values).

  13. Load Balancing Scheme on the Basis of Huffman Coding for P2P Information Retrieval

    Kurasawa, Hisashi; Takasu, Atsuhiro; Adachi, Jun

    Although a distributed index on a distributed hash table (DHT) enables efficient document query processing in Peer-to-Peer information retrieval (P2P IR), the index costs a lot to construct and it tends to be an unfair management because of the unbalanced term frequency distribution. We devised a new distributed index, named Huffman-DHT, for P2P IR. The new index uses an algorithm similar to Huffman coding with a modification to the DHT structure based on the term distribution. In a Huffman-DHT, a frequent term is assigned to a short ID and allocated a large space in the node ID space in DHT. Throuth ID management, the Huffman-DHT balances the index registration accesses among peers and reduces load concentrations. Huffman-DHT is the first approach to adapt concepts of coding theory and term frequency distribution to load balancing. We evaluated this approach in experiments using a document collection and assessed its load balancing capabilities in P2P IR. The experimental results indicated that it is most effective when the P2P system consists of about 30, 000 nodes and contains many documents. Moreover, we proved that we can construct a Huffman-DHT easily by estimating the probability distribution of the term occurrence from a small number of sample documents.

  14. SemTrust: A Semantic Reputation System in P2P-Based Semantic Web

    WANG Wei; ZENG Guosun; YUAN Lulai


    A reputation mechanism is introduced in P2P-based Semantic Web to solve the problem of lacking trust. It enables Semantic Web to utilize reputation information based on semantic similarity of peers in the network. This approach is evaluated in a simulation of a content sharing system and the experiments show that the system with reputation mechanism outperforms the system without it.

  15. Scaling laws for file dissemination in P2P networks with random contacts

    Núñez-Queija, R.; Prabhu, B.


    In this paper we obtain the scaling law for the mean broadcast time of a file in a P2P network with an initial population of N nodes. In the model, at Poisson rate lambda a node initiates a contact with another node chosen uniformly at random. This contact is said to be successful if the contacted n

  16. From P2P to Web services and grids peers in a client/server world

    Taylor, Ian J


    Provides an overview of peer-to-peer (P2P) technologies that have revolutionized the way we think about distributed computing and the internet. This book compares these technologies to alternative solutions, most notably web services and Grid computing but also other technologies, such as client/server based systems and agent technologies.

  17. IPTV-RM: A Resources Monitoring Architecture for P2P IPTV Systems

    Wenxian Wang


    Full Text Available Resources monitoring is an important problem of the overall efficient usage and control of P2P IPTV systems. The resources of IPTV can include all distributing servers, programs and peers. Several researches have tried to address this issue, but most of them illuminated P2P traffic characterization, identification and user behavior. The main contributions of this paper are twofold. Firstly, a resources monitoring architecture for P2P IPTV systems, IPTV-RM, was presented based on previous work. The monitoring architecture employs a hierarchical structure and provides systemic monitoring including resources discovery, relative information extraction and analysis, trace and location. It gives a systematic framework for IPTV resources monitoring. Secondly, a distributed program crawling system (DMP-Crawler was first proposed to collect information of programs, and a peer crawling system was put forward to harvest peers of a program. The results show that they are efficient and can be used for resource collection of other P2P system. 

  18. Scaling laws for file dissemination in P2P networks with random contacts

    Nunez-Queija, R.; Prabhu, B.


    In this paper we obtain the scaling law for the mean broadcast time of a file in a P2P network with an initial population of N nodes. In the model, at Poisson rate λ a node initiates a contact with another node chosen uniformly at random. This contact is said to be successful if the contacted node p

  19. Unstructured P2P Network Load Balance Strategy Based on Multilevel Partitioning of Hypergraph

    Feng, Lv; Chunlin, Gao; Kaiyang, Ma


    With rapid development of computer performance and distributed technology, P2P-based resource sharing mode plays important role in Internet. P2P network users continued to increase so the high dynamic characteristics of the system determine that it is difficult to obtain the load of other nodes. Therefore, a dynamic load balance strategy based on hypergraph is proposed in this article. The scheme develops from the idea of hypergraph theory in multilevel partitioning. It adopts optimized multilevel partitioning algorithms to partition P2P network into several small areas, and assigns each area a supernode for the management and load transferring of the nodes in this area. In the case of global scheduling is difficult to be achieved, the priority of a number of small range of load balancing can be ensured first. By the node load balance in each small area the whole network can achieve relative load balance. The experiments indicate that the load distribution of network nodes in our scheme is obviously compacter. It effectively solves the unbalanced problems in P2P network, which also improve the scalability and bandwidth utilization of system.

  20. Traceable P2P record exchange: a database-oriented approach

    Fengrong LI; Takuya IIDA; Yoshiharu ISHIKAWA


    In recent years,peer-to-peer (P2P) technologies are used for flexible and scalable information exchange in the Internet,but there exist problems to be solved for reliable information exchange.It is important to trace how data circulates between peers and how data modifications are performed during the circulation before reaching the destination for enhancing the reliability of exchanged information.However,such lineage tracing is not easy in current P2P networks,since data replications and modifications are performed independently by autonomous peers--this creates a lack of reliability among the records exchanged.In this paper,we propose a framework for traceable record exchange in a P2P network.By managing historical information in distributed peers,we make the modification and exchange histories of records traceable.One of the features of our work is that the database technologies are utilized for realizing the framework.Histories are maintained in a relational database in each peer,and tracing queries are written in the datalog query language and executed in a P2P network by cooperating peers.This paper describes the concept of the framework and overviews the approach to query processing.

  1. Identifying file-sharing P2P traffic based on traffic characteristics


    This article focuses on identifying file-sharing peer-to-peer (P2P) (such as BitTorrent (BT)) traffic at the borders of a stub network. By analyzing protocols and traffic of applications, it is found that file-sharing P2P traffic of a single user differs greatly from traditional and other P2P (such as QQ) applications' traffic in the distribution of involved remote hosts and remote ports. Therefore, a method based on discreteness of remote hosts (RHD) and discreteness of remote ports (RPD) is proposed to identify BT-like traffic. This method only relies on flow information of each user host in a stub network, and no packet payload needs to be monitored. At intervals, instant RHD for concurrent transmission control protocol and user datagram protocol flows for each host are calculated respectively through grouping flows by the stub network that the remote host of each flow belongs to. On given conditions, instant RPD are calculated through grouping flows by the remote port to amend instant RHD. Whether a host has been using a BT-like application or not can be deduced from instant RHD or average RHD for a period of time. The proposed method based on traffic characteristics is more suitable for identifying protean file-sharing P2P traffic than content-based methods. Experimental results show that this method is effective with high accuracy.

  2. Scaling laws for file dissemination in P2P networks with random contacts

    Núñez-Queija, R.; Prabhu, B.


    In this paper we obtain the scaling law for the mean broadcast time of a file in a P2P network with an initial population of N nodes. In the model, at Poisson rate lambda a node initiates a contact with another node chosen uniformly at random. This contact is said to be successful if the contacted

  3. End-to-End Key Exchange through Disjoint Paths in P2P Networks

    Daouda Ahmat


    Full Text Available Due to their inherent features, P2P networks have proven to be effective in the exchange of data between autonomous peers. Unfortunately, these networks are subject to various security threats that cannot be addressed readily since traditional security infrastructures, which are centralized, cannot be applied to them. Furthermore, communication reliability across the Internet is threatened by various attacks, including usurpation of identity, eavesdropping or traffic modification. Thus, in order to overcome these security issues and allow peers to securely exchange data, we propose a new key management scheme over P2P networks. Our approach introduces a new method that enables a secret key exchange through disjoint paths in the absence of a trusted central coordination point which would be required in traditional centralized security systems.

  4. A Fuzzy Reputation Management System with Punishment Mechanism for P2P Network

    Zhengbing Hu


    Full Text Available One way to minimize threats in P2P system is to exploit reputation to help evaluate the trustworthiness and predict the future behaviors of peers. In this paper, a set of parameters are identified for describing the trust of a peer. And a trust model based on fuzzy techniques is presented. The trust model uses Amplifier of Malicious Behavior (AMB to intensify malicious behaviors and helps peers identify the sly malicious peers. The recommendation credibility is evaluated by Recommendation Weight (RW and Recommendation Accuracy (RA. In simulation, this trust model has been shown to improve the efficiency of P2P system by significantly decreasing the number of inauthentic files on the network.

  5. DistHash: A robust P2P DHT-based system for replicated objects

    Dobre, Ciprian; Cristea, Valentin


    Over the Internet today, computing and communications environments are significantly more complex and chaotic than classical distributed systems, lacking any centralized organization or hierarchical control. There has been much interest in emerging Peer-to-Peer (P2P) network overlays because they provide a good substrate for creating large-scale data sharing, content distribution and application-level multicast applications. In this paper we present DistHash, a P2P overlay network designed to share large sets of replicated distributed objects in the context of large-scale highly dynamic infrastructures. We present original solutions to achieve optimal message routing in hop-count and throughput, provide an adequate consistency approach among replicas, as well as provide a fault-tolerant substrate.

  6. A Potential Approach of Internet Worm Propagation Based on P2P

    YAO Yu; LUO Xingrui; GAO Fuxiang; YU Ge


    Various kinds of active worms have been plunging into the network flows, which make the Internet security problem more serious. Our research on a potential propagation approach of active worms, P2P-based propagation approach, is given in this paper. To measure the propagating performance of our approach, the SEI (Susceptible-Exposed- Infected) propagation model is presented. It proves that with the idea of pure P2P architecture, worms can be hidden in the early stage of propagation, and then infect most of the hosts in a shorter period. By comparing our SEI propagation model with the Simple Epidemic Model, we observe that the size of a worm is a significant parameter which can affect the propagating performance. When the size of the worm becomes large, our approach can still show an excellent propagating performance.

  7. PISA: Federated Search in P2P Networks with Uncooperative Peers

    Ren, Zujie; Shou, Lidan; Chen, Gang; Chen, Chun; Bei, Yijun

    Recently, federated search in P2P networks has received much attention. Most of the previous work assumed a cooperative environment where each peer can actively participate in information publishing and distributed document indexing. However, little work has addressed the problem of incorporating uncooperative peers, which do not publish their own corpus statistics, into a network. This paper presents a P2P-based federated search framework called PISA which incorporates uncooperative peers as well as the normal ones. In order to address the indexing needs for uncooperative peers, we propose a novel heuristic query-based sampling approach which can obtain high-quality resource descriptions from uncooperative peers at relatively low communication cost. We also propose an effective method called RISE to merge the results returned by uncooperative peers. Our experimental results indicate that PISA can provide quality search results, while utilizing the uncooperative peers at a low cost.

  8. WebVR——Web Virtual Reality Engine Based on P2P network

    zhihan LV


    Full Text Available WebVR, a multi-user online virtual reality engine, is introduced. The main contributions are mapping the geographical space and virtual space to the P2P overlay network space, and dividing the three spaces by quad-tree method. The geocoding is identified with Hash value, which is used to index the user list, terrain data, and the model object data. Sharing of data through improved Kademlia network model is designed and implemented. In this model, XOR algorithm is used to calculate the distance of the virtual space. The model greatly improves the hit rate of 3D geographic data search under P2P overlay network. Some data preprocessing methods have been adopted to accelerate the data transfer. 3D Global data is used for testing the engine. The test result indicates that, without considering the client bandwidth limit, the more users, the faster loading.

  9. Using of P2P Networks for Acceleration of RTE Tasks Solving

    Adrian Iftene


    Full Text Available In the last years the computational Grids have become an important research area in large-scale scientific and engineering research. Our approach is based on Peer-to-peer (P2P networks, which are recognized as one of most used architectures in order to achieve scalability in key components of Grid systems. The main scope in using of a computational Grid was to improve the computational speed of systems that solve complex problems from Natural Language processing field. We will see how can be implemented a computational Grid using the P2P model, and how can be used SMB protocol for file transfer. After that we will see how we can use this computational Grid, in order to improve the computational speed of a system used in RTE competition [1], a new complex challenge from Natural Language processing field.

  10. Reducing Network Traffic in Unstructured P2P Systems Using Top-k Queries

    Akbarinia, Reza; Valduriez, Patrick; 10.1007/s10619-006-8313-5


    A major problem of unstructured P2P systems is their heavy network traffic. This is caused mainly by high numbers of query answers, many of which are irrelevant for users. One solution to this problem is to use Top-k queries whereby the user can specify a limited number (k) of the most relevant answers. In this paper, we present FD, a (Fully Distributed) framework for executing Top-k queries in unstructured P2P systems, with the objective of reducing network traffic. FD consists of a family of algorithms that are simple but effec-tive. FD is completely distributed, does not depend on the existence of certain peers, and addresses the volatility of peers during query execution. We vali-dated FD through implementation over a 64-node cluster and simulation using the BRITE topology generator and SimJava. Our performance evaluation shows that FD can achieve major performance gains in terms of communication and response time.

  11. High Quality of Service on Video Streaming in P2P Networks using FST-MDC

    Jaganathan, Suresh; 10.5121/ijma.2011.3203


    Video streaming applications have newly attracted a large number of participants in a distribution network. Traditional client-server based video streaming solutions sustain precious bandwidth provision rate on the server. Recently, several P2P streaming systems have been organized to provide on-demand and live video streaming services on the wireless network at reduced server cost. Peer-to-Peer (P2P) computing is a new pattern to construct disseminated network applications. Typical error control techniques are not very well matched and on the other hand error prone channels has increased greatly for video transmission e.g., over wireless networks and IP. These two facts united together provided the essential motivation for the development of a new set of techniques (error concealment) capable of dealing with transmission errors in video systems. In this paper, we propose an flexible multiple description coding method named as Flexible Spatial-Temporal (FST) which improves error resilience in the sense of fra...

  12. Predicting the Impact of Measures Against P2P Networks on the Transient Behaviors

    Altman, Eitan; Shwartz, Adam; Xu, Yuedong


    The paper has two objectives. The first is to study rigorously the transient behavior of some P2P networks where information is replicated and disseminated according to an epidemic type dynamics. The second is to use the insight gained in order to predict how efficient are measures taken against peer to peer networks. We first study a model which extends a classical epidemic model to characterize the peer to peer swarms in the presence of free riding peers. We then study a second model that a peer initiates a contact with another peer chosen randomly. In both cases, the network is shown to have a phase transition: a small change in the parameters causes a large change in the behavior of the network. We show in particular how the phase transition affects measures that content provider networks may take against P2P networks that distribute non-authorized music or books, and what is the efficiency of counter-measures.

  13. Proactive Uniform Data Replication by Density Estimation in Apollonian P2P Networks

    Bonnel, Nicolas; Ménier, Gildas; Marteau, Pierre-François

    We propose a data replication scheme on a random apollonian P2P overlay that benefits from the small world and scale free properties. The proposed algorithm features a replica density estimation and a space filling mechanism designed to avoid redundant messages. Not only it provides uniform replication of the data stored into the network but it also improves on classical flooding approaches by removing any redundancy. This last property is obtained at the cost of maintaining a random apollonian overlay. Thanks to the small world and scale free properties of the random apollonian P2P overlay, the search efficiency of the space filling tree algorithm we propose has comparable performances with the classical flooding algorithm on a random network.

  14. A hierarchical P2P overlay network for interest-based media contents lookup

    Lee, HyunRyong; Kim, JongWon


    We propose a P2P (peer-to-peer) overlay architecture, called IGN (interest grouping network), for contents lookup in the DHC (digital home community), which aims to provide a formalized home-network-extended construction of current P2P file sharing community. The IGN utilizes the Chord and de Bruijn graph for its hierarchical overlay network construction. By combining two schemes and by inheriting its features, the IGN efficiently supports contents lookup. More specifically, by introducing metadata-based lookup keyword, the IGN offers detailed contents lookup that can reflect the user interests. Moreover, the IGN tries to reflect home network environments of DHC by utilizing HG (home gateway) of each home network as a participating node of the IGN. Through experimental and analysis results, we show that the IGN is more efficient than Chord, a well-known DHT (distributed hash table)-based lookup protocol.

  15. Hybrid information retrieval policies based on cooperative cache in mobile P2P networks

    Quanqing XU; Hengtao SHEN; Zaiben CHEN; Bin CUI; Xiaofang ZHOU; Yafei DAI


    The concept of Peer-to-Peer (P2P) has been in-troduced into mobile networks, which has led to the emer-gence of mobile P2P networks, and originated potential ap-plications in many fields. However, mobile P2P networks are subject to the limitations of transmission range, and highly dynamic and unpredictable network topology, giving rise to many new challenges for efficient information retrieval. In this paper, we propose an automatic and economical hybrid information retrieval approach based on cooperative cache. In this method, the region covered by a mobile P2P network is partitioned into subregions, each of which is identified by a unique ID and known to all peers. All the subregions then constitute a mobile Kademlia (MKad) network. The pro-posed hybrid retrieval approach aims to utilize the flooding-based and Distributed Hash Table (DHT)-based schemes in MKad for indexing and searching according to the designed utility functions. To further facilitate information retrieval, we present an effective cache update method by considering all relevant factors. At the same time, the combination of two different methods for cache update is also introduced. One of them is pull based on time stamp including two different pulls: an on-demand pull and a periodical pull, and the other is a push strategy using update records. Furthermore, we provide detailed mathematical analysis on the cache hit ratio of our approach. Simulation experiments in NS-2 showed that the proposed approach is more accurate and efficient than the existing methods.

  16. A Distributed Architecture of Video Conference Using P2P Technology

    Xiaoyan Yu; Zhenyu Yu


    Most of the traditional video conferencing are standard SIP or H.323 architecture. There will be a single point of performance bottlenecks if large-scale video conference or a larger number of conferences emerge at the same time. In this paper, we proposed a new architecture of Multipoint Video Conference which can support a lot of meetings simultaneously using P2P and application multicast technology. In the side of server, the component called Media Control Server (MCS) is responsible for t...

  17. P2P相关技术的研究%Research of P2P technologies

    李秀君; 李成


    Peer-to-Peer(P2P) is a virtual network that is based on the underlying communication network infrastructure,and is a self-organizing system which is distributed and interoperable.Now,the software with P2P technology is in widespread use,and brings the users happiness,at the same time,resulting in a waste of network bandwidth.In order to make P2P more efficient operation and reduce network flow,this paper introduces the theory of the P4P technology.Through the study of the P2P technology,this article points out the contradiction between the P2P application and network operator,and analyzes the solution in detail.%对等网络(P2P)是一种构筑于底层通信网络基础设施之上的虚拟网络,是一个分布式的、具有互操作性的自组织系统。现在,运用P2P技术的软件比比皆是,使人们在不知不觉中感受到了P2P技术带来的快乐,与此同时它也浪费了大量的网络带宽。为了让P2P系统更高效的运行,同时降低网络的流量,本文介绍了P4P技术的相关理论。通过对P2P技术的研究,指出了P2P应用与网络运营商之间的矛盾,并对其解决办法进行了详细的分析。

  18. Protocols for Bio-Inspired Resource Discovery and Erasure Coded Replication in P2P Networks

    Thampi, Sabu M


    Efficient resource discovery and availability improvement are very important issues in unstructured P2P networks. In this paper, a bio-inspired resource discovery scheme inspired by the principle of elephants migration is proposed. A replication scheme based on Q-learning and erasure codes is also introduced. Simulation results show that the proposed schemes significantly increases query success rate and availability, and reduces the network traffic as the resources are effectively distributed to well-performing nodes.

  19. Doubly stochastic converge: uniform sampling for directed P2P networks

    Hall, Cyrus; Carzaniga, Antonio


    Uniformly sampling nodes from deployed peer-to-peer (P2P) networks has proven to be a difficult problem, as current techniques suffer from sample bias and limited applicability. A sampling service which randomly samples nodes from a uniform distribution across all members of a network offers a platform on which it is easy to construct unstructured search, data replication, and monitoring algorithms. We present an algorithm which allows for uniform random sampling, by the use of biased rand...

  20. Personalized Trust Management for Open and Flat P2P Communities

    ZUO Min; LI Jian-hua


    A personalized trust management scheme is proposed to help peers build up trust between each other in open and flat P2P communities. This scheme totally abandons the attempt to achieve a global view. It evaluates trust from a subjective point of view and gives personalized decision support to each peer. Simulation experiments prove its three advantages: free of central control, stronger immunity to misleading recommendations, and limited traffic overload.

  1. A Prediction System Using a P2P Overlay Network for a Bus Arrival System

    Ssu-Hsuan Lu


    Full Text Available Along with the evolution of times and the surge of metropolitan populations, government agencies often promote the construction of public transport. Unlike rail transportation or rapid transit systems, it is often difficult to estimate the vehicle arrival times at each station in a bus transportation system due to metropolitan transportation congestion. Traffic status is often monitored using wireless sensor networks (WSNs. However, WSNs are always separated from one another spatially. Recent studies have considered the connection of multiple sensor networks. This study considers a combination view of peer-to-peer (P2P overlay networks and WSN architecture to predict bus arrival times. Each bus station, which is also a P2P overlay peer, is connected in a P2P overlay network. A sensor installed in each bus can receive data via peers to obtain the moving speed of a bus. Then, each peer can exchange its data to predict bus arrival times at bus stations. This method can considerably increase the accuracy with which bus arrival times can be predicted and can provide traffic status with high precision. Furthermore, these data can also be used to plan new bus routes according to the information gathered.

  2. Optimally Efficient Prefix Search and Multicast in Structured P2P Networks

    Bradler, Dirk; Muehlhaeuser, Max


    Searching in P2P networks is fundamental to all overlay networks. P2P networks based on Distributed Hash Tables (DHT) are optimized for single key lookups, whereas unstructured networks offer more complex queries at the cost of increased traffic and uncertain success rates. Our Distributed Tree Construction (DTC) approach enables structured P2P networks to perform prefix search, range queries, and multicast in an optimal way. It achieves this by creating a spanning tree over the peers in the search area, using only information available locally on each peer. Because DTC creates a spanning tree, it can query all the peers in the search area with a minimal number of messages. Furthermore, we show that the tree depth has the same upper bound as a regular DHT lookup which in turn guarantees fast and responsive runtime behavior. By placing objects with a region quadtree, we can perform a prefix search or a range query in a freely selectable area of the DHT. Our DTC algorithm is DHT-agnostic and works with most exi...

  3. Agreement Maintenance Based on Schema and Ontology Change in P2P Environment

    Banowosari, L Y; Mutiara, A B


    This paper is concern about developing a semantic agreement maintenance method based on semantic distance by calculating the change of local schema or ontology. This approach is important in dynamic and autonomous environment, in which the current approach assumed that agreement or mapping in static environment. The contribution of this research is to develop a framework based on semantic agreement maintenance approach for P2P environment. This framework based on two level hybrid P2P model architecture, which consist of two peer type: (1) super peer that use to register and manage the other peers, and (2) simple peer, as a simple peer, it exports and shares its contents with others. This research develop a model to maintain the semantic agreement in P2P environment, so the current approach which does not have the mechanism to know the change, since it assumed that ontology and local schema are in the static condition, and it is different in dynamic condition. The main issues are how to calculate the change of...

  4. Design and Implementation Aspects of a novel Java P2P Simulator with GUI

    Chrissikopoulos, V; Sakkopoulos, E; Sioutas, S


    Peer-to-peer networks consist of thousands or millions of nodes that might join and leave arbitrarily. The evaluation of new protocols in real environments is many times practically impossible, especially at design and testing stages. The purpose of this paper is to describe the implementation aspects of a new Java based P2P simulator that has been developed to support scalability in the evaluation of such P2P dynamic environments. Evolving the functionality presented by previous solutions, we provide a friendly graphical user interface through which the high-level theoretic researcher/designer of a P2P system can easily construct an overlay with the desirable number of nodes and evaluate its operations using a number of key distributions. Furthermore, the simulator has built-in ability to produce statistics about the distributed structure. Emphasis was given to the parametrical configuration of the simulator. As a result the developed tool can be utilized in the simulation and evaluation procedures of a vari...

  5. The PeerBehavior Model based on Continuous Behavioral Observation P2P Network Neighbors

    Xianwen Wu


    Full Text Available Honor-based trust mechanism is an important means to evaluate the behavior of the P2P network node, and it is used to ensure the health of the P2P network application. Trust mechanisms need to evaluate a node to other node local trust value and local trust value because they do not consider the policy node and human evaluation error of two important factors. The calculation is difficult to accurately reflect the characteristics of the nodes of the network. Evaluation models of the behavior of a P2P network neighbor. The PeerBehavior model has used a deterministic finite state machine (DFA depicts the continuous behavior of the neighbor state changes cause a negative evaluation of any continuous behavior by focusing neighbors almost died, both able to more accurately discover policies node in the network, but also be able to tolerate a certain degree of human evaluation error simulation experiment showed that this model was significantly improve the accuracy of the local trust value, and reducing the estimation error of the global trust value, was significantly superior to the calculation method of the current value of the other local trust

  6. Hybrid CDN structure with a P2P based streaming protocol

    Pushp, Saumay


    Over the last decade, internet has seen an exponential increase in its growth.With more and more people using it, efficient data delivery over the internet has become a key issue. Peer-to-peer (P2P)/seed sharing based networks have several desirable features for content distribution, such as low costs, scalability, and fault tolerance. While the invention of each of such specialized systems has improved the user experience, some fundamental shortcomings of these systems have often been neglected. These shortcomings of content distribution systems have become severe bottlenecks in scalability of the internet.In order to combine the desired features of classical Content Distribution Networks (CDNs) and P2P/seed sharing based networks, we propose a hybrid CDN structure with a P2P/seed sharing based streaming protocol in the access network . In this work, we focus on the problem of data redundancy (at each node) and show how severely it impacts the network economics and the experience of end-user and hence leads ...

  7. Fault Tolerant PLBGSA: Precedence Level Based Genetic Scheduling Algorithm for P2P Grid

    Piyush Chauhan


    Full Text Available Due to monetary limitation, small organizations cannot afford high end supercomputers to solve highly complex tasks. P2P (peer to peer grid computing is being used nowadays to break complex task into subtasks in order to solve them on different grid resources. Workflows are used to represent these complex tasks. Finishing such complex task in a P2P grid requires scheduling subtasks of workflow in an optimized manner. Several factors play their part in scheduling decisions. The genetic algorithm is very useful in scheduling DAG (directed acyclic graph based task. Benefit of a genetic algorithm is that it takes into consideration multiple criteria while scheduling. In this paper, we have proposed a precedence level based genetic algorithm (PLBGSA, which yields schedules for workflows in a decentralized fashion. PLBGSA is compared with existing genetic algorithm based scheduling techniques. Fault tolerance is a desirable trait of a P2P grid scheduling algorithm due to the untrustworthy nature of grid resources. PLBGSA handles faults efficiently.

  8. SiMPSON: Efficient Similarity Search in Metric Spaces over P2P Structured Overlay Networks

    Vu, Quang Hieu; Lupu, Mihai; Wu, Sai

    Similarity search in metric spaces over centralized systems has been significantly studied in the database research community. However, not so much work has been done in the context of P2P networks. This paper introduces SiMPSON: a P2P system supporting similarity search in metric spaces. The aim is to answer queries faster and using less resources than existing systems. For this, each peer first clusters its own data using any off-the-shelf clustering algorithms. Then, the resulting clusters are mapped to one-dimensional values. Finally, these one-dimensional values are indexed into a structured P2P overlay. Our method slightly increases the indexing overhead, but allows us to greatly reduce the number of peers and messages involved in query processing: we trade a small amount of overhead in the data publishing process for a substantial reduction of costs in the querying phase. Based on this architecture, we propose algorithms for processing range and kNN queries. Extensive experimental results validate the claims of efficiency and effectiveness of SiMPSON.

  9. SKIP:an efficient search mechanism in unstructured P2P networks

    SHEN Wen-wu; SU Sen; SHUANG Kai; YANG Fang-chun


    Search efficiency and accuracy of resource are important considerations for search algorithm in peer-to-peer(P2P)network.Most search algorithms use flooding among neighbor nodes to search relevant resource.However,this usually causes great amount of redundant messages,which results in high search costs and low search precision.In this paper,we use vector space model(VSM)and relevance ranking algorithms to construct overlay network,and a novel search mechanism search with K-iteration preference(SKIP)based on semantic group for P2P networks is proposed to efficiently solve these problems.The key idea of SKIP is to reorder the semantic neighbors of nodes according to relevant scores and to utilize preference selection during the process of query.We analysis and implement the scheme and reveal that the SKIP provides a low overhead on topology maintenance,which can be effectively used in P2P searching and verify it outperformanee in higher precision and lower search cost by comparing with current semantic-based searching mechanism gnutella-like efficient searching system(GES).

  10. Emergence of Financial Intermediaries in Electronic Markets: The Case of Online P2P Lending

    Sven C. Berger


    Full Text Available We analyze the role of intermediaries in electronic markets using detailed data of more than 14,000 originated loans on an electronic P2P (peer-to-peer lending platform. In such an electronic credit market, lenders bid to supply a private loan. Screening of potential borrowers and the monitoring of loan repayment can be delegated to designated group leaders. We find that these market participants act as financial intermediaries and significantly improve borrowers' credit conditions by reducing information asymmetries, predominantly for borrowers with less attractive risk characteristics. Our findings may be surprising given the replacement of a bank by an electronic marketplace.

  11. A P2P Service Discovery Strategy Based on Content Catalogues

    Lican Huang


    Full Text Available This paper presents a framework for distributed service discovery based on VIRGO P2P technologies. The services are classified as multi-layer, hierarchical catalogue domains according to their contents. The service providers, which have their own service registries such as UDDIs, register the services they provide and establish a virtual tree in a VIRGO network according to the domain of their service. The service location done by the proposed strategy is effective and guaranteed. This paper also discusses the primary implementation of service discovery based on Tomcat/Axis and jUDDI.

  12. Nuclear transparency in 90 °c.m. quasielastic A(p,2p) reactions

    Aclander, J.; Alster, J.; Asryan, G.; Averiche, Y.; Barton, D. S.; Baturin, V.; Buktoyarova, N.; Bunce, G.; Carroll, A. S.; Christensen, N.; Courant, H.; Durrant, S.; Fang, G.; Gabriel, K.; Gushue, S.; Heller, K. J.; Heppelmann, S.; Kosonovsky, I.; Leksanov, A.; Makdisi, Y. I.; Malki, A.; Mardor, I.; Mardor, Y.; Marshak, M. L.; Martel, D.; Minina, E.; Minor, E.; Navon, I.; Nicholson, H.; Ogawa, A.; Panebratsev, Y.; Piasetzky, E.; Roser, T.; Russell, J. J.; Schetkovsky, A.; Shimanskiy, S.; Shupe, M. A.; Sutton, S.; Tanaka, M.; Tang, A.; Tsetkov, I.; Watson, J.; White, C.; Wu, J.-Y.; Zhalov, D.


    We summarize the results of two experimental programs at the Alternating Gradient Synchrotron of BNL to measure the nuclear transparency of nuclei measured in the A(p,2p) quasielastic scattering process near 90° in the pp center of mass. The incident momenta varied from 5.9 to 14.4 GeV/c , corresponding to 4.8< Q2 <12.7 (GeV/c)2 . Taking into account the motion of the target proton in the nucleus, the effective incident momenta extended from 5.0 to 15.8 GeV/c . First, we describe the measurements with the newer experiment, E850, which had more complete kinematic definition of quasielastic events. E850 covered a larger range of incident momenta, and thus provided more information regarding the nature of the energy dependence of the nuclear transparency. In E850 the angular dependence of the nuclear transparency near 90° and the nuclear transparency deuterons were studied. Second, we review the techniques used in an earlier experiment, E834, and show that the two experiments are consistent for the carbon data. E834 also determines the nuclear transparencies for lithium, aluminum, copper, and lead nuclei as well as for carbon. A determination of the ( π+ , π+ p) transparencies is also reported. We find for both E850 and E834 that the A(p,2p) nuclear transparency, unlike that for A(e, e' p) nuclear transparency, is incompatible with a constant value versus energy as predicted by Glauber calculations. The A(p,2p) nuclear transparency for carbon and aluminum increases by a factor of two between 5.9 and 9.5 GeV/c incident proton momentum. At its peak the A(p,2p) nuclear transparency is ˜80% of the constant A(e, e' p) nuclear transparency. Then the nuclear transparency falls back to a value at least as small as that at 5.9 GeV/c , and is compatible with the Glauber level again. This oscillating behavior is generally interpreted as an interplay between two components of the pN scattering amplitude; one short ranged and perturbative, and the other long ranged and

  13. Towards Accurate Node-Based Detection of P2P Botnets

    Chunyong Yin


    Full Text Available Botnets are a serious security threat to the current Internet infrastructure. In this paper, we propose a novel direction for P2P botnet detection called node-based detection. This approach focuses on the network characteristics of individual nodes. Based on our model, we examine node’s flows and extract the useful features over a given time period. We have tested our approach on real-life data sets and achieved detection rates of 99-100% and low false positives rates of 0–2%. Comparison with other similar approaches on the same data sets shows that our approach outperforms the existing approaches.

  14. Simulación de una aplicación P2P empleando Oversim

    Martínez Rojo, Antonio M.; Sánchez Aarnoutse, Juan Carlos Jacobo


    Oversim es un entorno de simulación de redes overlay de código abierto basado en el simulador de eventos discretos OMNET++. Entre las ventajas principales de OverSim se puede destacar que incluye los principales protocolos P2P (Peer-to-Peer) tanto estructurados como no estructurados, así como mixtos. Además permite simular todas las capas de red subyacentes (de la capa MAC en adelante) gracias al entorno INET. Por estas y otras razones, Oversim solventa varios de los inconvenientes de los ...

  15. Cooperation enhanced by indirect reciprocity in spatial prisoner's dilemma games for social P2P systems

    Tian, Lin-Lin; Li, Ming-Chu; Wang, Zhen


    With the growing interest in social Peer-to-Peer (P2P) applications, relationships of individuals are further exploited to improve the performances of reputation systems. It is an on-going challenge to investigate how spatial reciprocity aids indirect reciprocity in sustaining cooperation in practical P2P environments. This paper describes the construction of an extended prisoner's dilemma game on square lattice networks with three strategies, i.e., defection, unconditional cooperation, and reciprocal cooperation. Reciprocators discriminate partners according to their reputations based on image scoring, where mistakes in judgment of reputations may occur. The independent structures of interaction and learning neighborhood are discussed, with respect to the situation in which learning environments differ from interaction networks. The simulation results have indicated that the incentive mechanism enhances cooperation better in structured peers than among a well-mixed population. Given the realistic condition of inaccurate reputation scores, defection is still successfully held down when the players interact and learn within the unified neighborhoods. Extensive simulations have further confirmed the positive impact of spatial structure on cooperation with different sizes of lattice neighborhoods. And similar conclusions can also be drawn on regular random networks and scale-free networks. Moreover, for the separated structures of the neighborhoods, the interaction network has a critical effect on the evolution dynamics of cooperation and learning environments only have weaker impacts on the process. Our findings further provide some insights concerning the evolution of collective behaviors in social systems.

  16. A P2P Framework for Developing Bioinformatics Applications in Dynamic Cloud Environments

    Chun-Hung Richard Lin


    Full Text Available Bioinformatics is advanced from in-house computing infrastructure to cloud computing for tackling the vast quantity of biological data. This advance enables large number of collaborative researches to share their works around the world. In view of that, retrieving biological data over the internet becomes more and more difficult because of the explosive growth and frequent changes. Various efforts have been made to address the problems of data discovery and delivery in the cloud framework, but most of them suffer the hindrance by a MapReduce master server to track all available data. In this paper, we propose an alternative approach, called PRKad, which exploits a Peer-to-Peer (P2P model to achieve efficient data discovery and delivery. PRKad is a Kademlia-based implementation with Round-Trip-Time (RTT as the associated key, and it locates data according to Distributed Hash Table (DHT and XOR metric. The simulation results exhibit that our PRKad has the low link latency to retrieve data. As an interdisciplinary application of P2P computing for bioinformatics, PRKad also provides good scalability for servicing a greater number of users in dynamic cloud environments.

  17. Improving Success Ratio of Object Search in Highly-Dynamic Mobile P2P Networks

    Takeshita, Kei; Sasabe, Masahiro; Nakano, Hirotaka

    Mobile Ad Hoc Networks (MANETs) are temporal and infrastructure-independent wireless networks that consist of mobile nodes. For instance, a MANET can be used as an emergent network for communication among people when a disaster occurred. Since there is no central server in the network, each node has to find out its desired information (objects) by itself. Constructing a mobile Peer-to-Peer (P2P) network over the MANET can support the object search. Some researchers proposed construction schemes of mobile P2P networks, such as Ekta and MADPastry. They integrated DHT-based application-layer routing and network-layer routing to increase search efficiency. Furthermore, MADPastry proposed a clustering method which groups the overlay nodes according to their physical distance. However, it has also been pointed out that the search efficiency deteriorates in highly dynamic environments where nodes quickly move around. In this paper, we focus on route disappearances in the network layer which cause the deterioration of search efficiency. We describe the detail of this problem and evaluate quantitatively it through simulation experiments. We extend MADPastry by introducing a method sharing objects among nodes in a cluster. Through simulation experiments, we show that the proposed method can achieve up to 2.5 times larger success rate of object search than MADPastry.

  18. Nuclear Transparency in 90 Degree c.m. Quasielastic A(p,2p) Reactions

    Aclander, J; Asryan, G; Averiche, Y; Barton, D S; Baturin, V; Buktoyarova, N; Bunce, G M; Carroll, A S; Christensen, N; Courant, H; Durrant, S; Fang, G; Gabriel, K; Gushue, S; Heller, K J; Heppelmann, S; Kosonovsky, I; Leksanov, A; Makdisi, Y I; Malki, A; Mardor, I; Mardor, Y; Marshak, M L; Martel, D; Minina, E; Minor, E; Navon, I; Nicholson, H; Ogawa, A; Panebratsev, Yu A; Piasetzky, E; Roser, T; Russell, J J; Schetkovsky, A; Shimansky, S S; Shupe, M A; Sutton, S; Tanaka, M; Tang, A; Tsetkov, I; Watson, J; White, C; Wu, J Y; Zhalov, D


    We summarize the results of two experimental programs at the Alternating Gradient Synchrotron of BNL to measure the nuclear transparency of nuclei measured in the A(p,2p) quasielastic scattering process near 90 Deg .in the pp center of mass. The incident momenta varied from 5.9 to 14.4 GeV/c, corresponding to 4.8 < Q^2 < 12.7 (GeV/c)^2. First, we describe the measurements with the newer experiment, E850, which had more complete kinematic definition of quasielastic events. In E850 the angular dependence of the nuclear transparency near 90 Deg. c.m., and the nuclear transparency for deuterons was studied. Second, we review the techniques used in an earlier experiment, E834, and show that the two experiments are consistent for the Carbon data. E834 also determines the nuclear transparencies for Li, Al, Cu, and Pb nuclei as well as for C. We find for both E850 and E834 that the A(p,2p) nuclear transparency, unlike that for A(e,e'p) nuclear transparency, is incompatible with a constant value versus energy as...

  19. Incentive Mechanism for P2P Content Sharing over Heterogenous Access Networks

    Sato, Kenichiro; Hashimoto, Ryo; Yoshino, Makoto; Shinkuma, Ryoichi; Takahashi, Tatsuro

    In peer-to-peer (P2P) content sharing, users can share their content by contributing their own resources to one another. However, since there is no incentive for contributing contents or resources to others, users may attempt to obtain content without any contribution. To motivate users to contribute their resources to the service, incentive-rewarding mechanisms have been proposed. On the other hand, emerging wireless technologies, such as IEEE 802.11 wireless local area networks, beyond third generation (B3G) cellular networks and mobile WiMAX, provide high-speed Internet access for wireless users. Using these high-speed wireless access, wireless users can use P2P services and share their content with other wireless users and with fixed users. However, this diversification of access networks makes it difficult to appropriately assign rewards to each user according to their contributions. This is because the cost necessary for contribution is different in different access networks. In this paper, we propose a novel incentive-rewarding mechanism called EMOTIVER that can assign rewards to users appropriately. The proposed mechanism uses an external evaluator and interactive learning agents. We also investigate a way of appropriately controlling rewards based on the system service's quality and managing policy.

  20. UCIMssp: Ubiquitous Computing Identification Mechanism Based on SPKI/SDSI and P2P

    SUN Dao-qing; PU Fang; CAO Qi-ying


    Ubiquitous computing systems typically have lots of security problems in the area of identification supply by means of classical Public Key Infrastructure(PKI)methods.The limited computing resources,the disconnection network,the classification requirements of ideatification,the requirement of trust transfer and cross identification,the bidirectional identification,the security delegation and the privacy protection etc are all these unsolved problems.In this paper,UCIMssp,a new novel ubiquitous computing identification mechanism based on SPKI/SDSI and Peer-to-Peer(P2P)is presented.SPKI based authorization Is exploited in UCIMssp to solve the above problems in the small-scale ubiquitous computing environment.The DHT and flooding technology of P2P overlay network over the Internet is expanded to solve the routing search in the large-scale ubiquitous computing environment.The architecture of ubiquitous computing environment,the validation of identification requisition,the identification authorization processes and the identification supply processes etc of UCIMssp are described in the paper.The performance analysis shows that UCIMssp is a suitable security solution used in the large-scale ubiquitous computing environment.

  1. B3A: Prompting Cooperation Among Rational Participants in P2P Bulk File Sharing Environments


    Peer-to-peer (P2P) file sharing systems assume that their users download files in proportion to their sharing. Unfortunately, users are unlikely to do so without an incentive mechanism. Previous solutions to the problem required some types of centralized control, which strays from the spirit of P2P to provide long-term incentives. This paper presents the balance-based bandwidth allocation, B3A, an incentive framework to inspire participants to share files. In the B3A framework, each peer keeps the differences between the amount of data it has received from each peer and the amount it has sent to that one. When receiving simultaneous requests from various peers, the peer prefers to allocate its limited upload bandwidth to those peers with larger differences. Therefore, the downloading bandwidth perceived by a peer is positively related to its contributions to others, consequently stimulating it to share more files. The B3A framework is fully decentralized, scalable, and secure.

  2. Design and Implementation of an Automated Management Platform for P2P Transactions with Electronic Money

    Andrés Alcocer


    Full Text Available Electronic money is a payment tool implemented by the Ecuador’s Central Bank, it allows people to make commercial transactions using their cellphones; it can be used to pay into big chain stores like supermarkets, known as "macro agents", but it also can be employed for the consumption of goods and services into particular businesses such as restaurants or small shops by using “person to person” transfers known as P2P. However, the particular businesses present some disadvantages compared to the macro agents, the main one is the lack of a system that allows them to have a record of the transactions made with electronic money. This article details the design and implementation of a technological platform that allows all types of businesses and people to keep records of their P2P transactions into an automated system with the ability of generating payment’s balance sheets which can be easily viewed through Internet. A research was conducted in order to look for the most efficient technical solution to optimize the available resources. The use of this platform as an external tool extends the capabilities currently provided by the electronic money system.

  3. Peer selecting model based on FCM for wireless distributed P2P files sharing systems

    LI Xi; JI Hong; ZHENG Rui-ming


    Ⅱn order to improve the performance of wireless distributed peer-to-peer(P2P)files sharing systems,a general system architecture and a novel peer selecting model based on fuzzy cognitive maps(FCM)are proposed in this paper.The new model provides an effective approach on choosing an optimal peer from several resource discovering results for the best file transfer.Compared with the traditional rain-hops scheme that uses hops as the only selecting criterion,the proposed model uses FCM to investigate the complex relationships among various relative factors in wireless environments and gives an overall evaluation score on the candidate.It also has strong scalability for being independent of specified P2P resource discovering protocols.Furthermore,a complete implementation is explained in concrete modules.The simulation results show that the proposed model is effective and feasible compared with rain-hops scheme,with the success transfer rate increased by at least20% and transfer time improved as high as 34%.

  4. A Measurement Study of the Structured Overlay Network in P2P File-Sharing Systems

    Mo Zhou


    Full Text Available The architecture of P2P file-sharing applications has been developing to meet the needs of large scale demands. The structured overlay network, also known as DHT, has been used in these applications to improve the scalability, and robustness of the system, and to make it free from single-point failure. We believe that the measurement study of the overlay network used in the real file-sharing P2P systems can provide guidance for the designing of such systems, and improve the performance of the system. In this paper, we perform the measurement in two different aspects. First, a modified client is designed to provide view to the overlay network from a single-user vision. Second, the instances of crawler programs deployed in many nodes managed to crawl the user information of the overlay network as much as possible. We also find a vulnerability in the overlay network, combined with the character of the DNS service, a more serious DDoS attack can be launched.

  5. Improving Resilience against DDoS Attack in Unstructured P2P Networks

    MA Xin-Xin; ZHAO Yang; QIN Zhi-Guang


    In unstructured peer-to-peer (P2P) systems such as Gnutella, a general routing search algorithm is used to blindly flood a query through network among peers. But unfortunately, malicious nodes could easily make use of the search approach launching distributed denial of service (DDoS) attack which aims at the whole network. In order to alleviate or minimize the bad effect due to behavior of malicious nodes using the flooding search mechanism, the paper proposes a Markov-based evaluation model which exerts the trust and reputation mechanism to computing the level of trustworthy of nodes having the information requested by evaluation of the nodes' history behavior. Moreover, it can differentiate malicious nodes as early as possible for isolating and controlling the ones' message transmitted. The simulation results of the algorithm proposed show that it could effectively isolate malicious nodes,and hold back the transmission of vicious messages so that it could enhance tolerance of DDoS based on flooding in Gnutella-like P2P network.

  6. Minimizing Redundant Messages and Improving Search Efficiency under Highly Dynamic Mobile P2P Network

    Ajay Arunachalam


    Full Text Available Resource Searching is one of the key functional tasks in large complex networks. With the P2P architecture, millions of peers connect together instantly building a communication pattern. Searching in mobile networks faces additional limitations and challenges. Flooding technique can cope up with the churn and searches aggressively by visiting almost all the nodes. But it exponentially increases the network traffic and thus does not scale well. Further the duplicated query messages consume extra battery power and network bandwidth. The blind flooding also suffers from long delay problem in P2P networks. In this paper, we propose optimal density based flooding resource discovery schemes. Our first model takes into account local graph topology information to supplement the resource discovery process while in our extended version we also consider the neighboring node topology information along with the local node information to further effectively use the mobile and network resources. Our proposed method reduces collision at the same time minimizes effect of redundant messages and failures. Overall the methods reduce network overhead, battery power consumption, query delay, routing load, MAC load and bandwidth usage while also achieving good success rate in comparison to the other techniques. We also perform a comprehensive analysis of the resource discovery schemes to verify the impact of varying node speed and different network conditions.

  7. Secure Data Exchange in P2P Data Sharing Systems in eHealth Perspective

    Mehedi Masud


    Full Text Available In P2P data sharing systems (P2PDSS peers share data in a pair-wise fashion. Data are shared on-the-fly by establishing temporary data exchange session for user queries. Generally, the communication link between peers is unsecured while exchanging data. In P2P eHealth data sharing scenarios, peers may need to exchange highly confidential data among them. Hence, there are some security threats that need to be considered (e.g. data might be trapped and disclosed by the intruders. In a P2PDSS, we cannot assume any third party security infrastructure (e.g. PKI to protect confidential data. Considering the need of secure data exchange in P2PDSS, in this paper we propose a secure data exchange model. The model is based on pairing-based cryptography and the data sharing policy between peers. Applying the model, peers compute secret session keys dynamically by computing pairing on elliptic curve, based on the data sharing policies while exchanging data. The proposed protocol is robust against the man-in-the middle attack, the masquerade attack and the replay attack.

  8. Multilevel Bloom Filters for P2P Flows Identification Based on Cluster Analysis in Wireless Mesh Network

    Xia-an Bi


    Full Text Available With the development of wireless mesh networks and distributed computing, lots of new P2P services have been deployed and enrich the Internet contents and applications. The rapid growth of P2P flows brings great pressure to the regular network operation. So the effective flow identification and management of P2P applications become increasingly urgent. In this paper, we build a multilevel bloom filters data structure to identify the P2P flows through researches on the locality characteristics of P2P flows. Different level structure stores different numbers of P2P flow rules. According to the characteristics values of the P2P flows, we adjust the parameters of the data structure of bloom filters. The searching steps of the scheme traverse from the first level to the last level. Compared with the traditional algorithms, our method solves the drawbacks of previous schemes. The simulation results demonstrate that our algorithm effectively enhances the performance of P2P flows identification. Then we deploy our flow identification algorithm in the traffic monitoring sensors which belong to the network traffic monitoring system at the export link in the campus network. In the real environment, the experiment results demonstrate that our algorithm has a fast speed and high accuracy to identify the P2P flows; therefore, it is suitable for actual deployment.

  9. Global Trust Value Grading Calculation Method in P2P Network

    Min Liu


    Full Text Available The paper has proposed that the global situation trust value doesn’t depend on any set of high trust nodes in a P2P network environment of grading calculating model. It has given its distributed implementation. This model introduces subtraction clustering method to a large-scale network is logically divided into a number of small networks, and re-organized as overlay network structure of the upper and lower levels, the iterative algorithms in parallel in a small-scale network. Global situation trust value of each node is obtained, the convergence of the iteration level synthesis iterations results. Theoretical analysis and simulation results show that, compared with the existing model, the model has improved greatly reduce the amount of computation and communication overhead, and accelerate the iterative convergence.

  10. SPF-A*: Searching Multimedia Data in Heterogeneous Mobile P2P Network

    Fan Ye


    Full Text Available Mobile P2P (MP2P network has been widely used in everyday life combined with the wireless technology development. However, most previous works concentrate on the assumption that the mobile peers are identical of their inner properties in compositing a MP2P network. However, in current network environment, heterogeneous devices are widely used; they may have different storage sizes, data transmission rate, processing ability and even security levels. In such kind of MP2P Network environment, how to make data transmission effectively is challenge. In this paper, we concentrate on how to effectively obtain a queried multimedia resource and generate a path for such data transmission on the overlay MP2P network, so as to make the resource more effectively transmit among the heterogeneous peers. A new path generating algorithm called SPF-A* (Super Peer First A* is devised, and simulation studies are conducted to validate our proposal.

  11. Data Integration Strategy for Database Grids Based on P2P Framework

    WANG Guangqi; SHEN Derong; YU Ge; ZHOU Wensheng; LI Meifang


    The differences between the data integration of a dynamic database grid (DBG) and that of a distributed database system are analyzed, and three kinds of data integration strategies are given on the background of DBG based on Peer to Peer (P2P) framework, including the centralized data integration (CDI) strategy, the distributed data integration (DDI) strategy and the filter-based data integration (FDDI) strategy. CDI calls all the database grid services (DGSs) at a single node, DDI disperses the DGSs to multiple nodes, while FDDI schedules the data integration nodes based on filtering the keywords returned from DGSs. The performance of these three integration strategies are compared with and analyzed by simulation experiments. FDDI is more evident for filtering the keywords with data redundancy increasing. Through the reduction of large amount of data transportation, it effectively shortens the executing time for the task and improves its efficiency.

  12. A Secure Protocol for Sharing Trust Data in Hybrid P2P Network

    Huaiqing Lin


    Full Text Available The trust data is critical to the trust model of P2P system. In this paper we present an efficient certificateless cryptography scheme and propose a protocol which provides the ability for sharing trust data securely. The protocol avoids the escrow problem identity-based cryptosystem and the secure delivery of private keys. The security of scheme is based on some underlying problems closely related to the Bilinear Diffie-Hellman Problem are computationally hard. It tolerates the Type I and Type II adversary. The proof of security is presented in the random oracle model.  Through security discussion, we show that my secure protocol is extremely secure when encounter a variety of possible attacks.

  13. HDNBS: An approach for search in decentralized and unstructured P2P


    Decentralized and unstructured peer-to-peer applications such as Gnutella are attractive because they require no centralized directories and no precise control over network topology or data placement. Search algorithm is the major component of the distributed system and its efficiency also does influence the systems performance. However the flooding-based query algorithm used in Gnutella produces huge traffic and does not scale well. Gnutella-like P2P topology has power-law characteristic, so a search algorithm was, proposed based on high degree nodes of power-law network, High Degree Nodes-Based Search (HDNBS). Extensive simulation results show that this algorithm performs on power-law networks very well. Achieves almost 100% success rates, produces O(logN) messages per query and can locate target file within O(lonN) hops.

  14. P2P Video Streaming Strategies based on Scalable Video Coding

    F.A. López-Fuentes


    Full Text Available Video streaming over the Internet has gained significant popularity during the last years, and the academy and industry have realized a great research effort in this direction. In this scenario, scalable video coding (SVC has emerged as an important video standard to provide more functionality to video transmission and storage applications. This paper proposes and evaluates two strategies based on scalable video coding for P2P video streaming services. In the first strategy, SVC is used to offer differentiated quality video to peers with heterogeneous capacities. The second strategy uses SVC to reach a homogeneous video quality between different videos from different sources. The obtained results show that our proposed strategies enable a system to improve its performance and introduce benefits such as differentiated quality of video for clients with heterogeneous capacities and variable network conditions.

  15. Continually Answering Constraint k-NN Queries in Unstructured P2P Systems

    Bin Wang; Xiao-Chun Yang; Guo-Ren Wang; Ge Yu; Lei Chen; X. Sean Wang,; Xue-Min Lin


    We consider the problem of efficiently computing distributed geographical k-NN queries in an unstructured peer-to-peer (P2P) system, in which each peer is managed by an individual organization and can only communicate with its logical neighboring peers. Such queries are based on local filter query statistics, and require as less communication cost as possible, which makes it more difficult than the existing distributed k-NN queries. Especially, we hope to reduce candidate peers and degrade communication cost. In this paper, we propose an efficient pruning technique to minimize the number of candidate peers to be processed to answer the k-Nnqueries. Our approach is especially suitable for continuous k-Nnqueries when updating peers, including changing ranges of peers, dynamically leaving or joining peers, and updating data in a peer.In addition, simulation results show that the proposed approach outperforms the existing Minimum Bounding Rectangle (MBR)-based query approaches, especially for continuous queries.

  16. Modeling and analysis of the effectiveness of two redistributing schemes in P2P streaming network

    Gaidamaka, Yu.; Medvedeva, E.; Adamu, A.


    This paper explores so called "View-Upload Decoupling scheme" which strictly decouples data to what peer uploads and what it personally views. It is based on the split of downloaded user data streams into two types: the stream of the chosen TV channel and the stream (one or more) of the other TV channel, exclusively, to deliver it to other users. We developed a method for calculating one of the key QoS characteristics in P2P streaming network - the probability of universal streaming for each channel and a system-wide universal streaming across all channels. The statistical probability results of universal streaming for the VUD scheme compared to the traditional redistributing ISO scheme are presented.

  17. Measurement of quasi-elastic 12C(p,2p) scattering at high momentum transfer

    Mardor, Y.; Aclander, J.; Alster, J.; Barton, D.; Bunce, G.; Carroll, A.; Christensen, N.; Courant, H.; Durrant, S.; Gushue, S.; Heppelmann, S.; Kosonovsky, E.; Mardor, I.; Marshak, M.; Makdisi, Y.; Minor, E. D.; Navon, I.; Nicholson, H.; Piasetzky, E.; Roser, T.; Russell, J.; Sutton, C. S.; Tanaka, M.; White, C.; Wu, J.-Y.


    We measured the high-momentum transfer [Q2=4.8 and 6.2 (GeV/c)2] quasi-elastic 12C(p,2p) reaction at θcm~=90 deg for 6 and 7.5 GeV/c incident protons. The momentum components of both outgoing protons and the missing energy and momentum of the proton in the nucleus were measured. We verified the validity of the quasi-elastic picture for ground state momenta up to about 0.5 GeV/c. Transverse and longitudinal momentum distributions of the target proton were measured. They have the same shape with a large momentum tail which is not consistent with independent particle models. We observed that the transverse distribution gets wider as the longitudinal component increases in the beam direction.

  18. P2P-SIP通信系统研究与设计




  19. Deadline-aware network coding for video on demand service over P2P networks

    CHI Hui-cheng; ZHANG Qian


    We are interested in providing Video-on-Demand (VoD) streaming service to a large population of clients using peer-to-peer (P2P) approach. Given the asynchronous demands from multiple clients, continuously changing of the buffered contents, and the continuous video display requirement, how to collaborate with potential partners to get expected data for future content delivery are very important and challenging. In this paper, we develop a novel scheduling algorithm based on deadlineaware network coding (DNC) to fully exploit the network resource for efficient VoD service. DNC generalizes the existing network coding (NC) paradigm, an elegant solution for ubiquitous data distribution. Yet, with deadline awareness, DNC improves the network throughput and meanwhile avoid missing the play deadline in high probability, which is a major deficiency of the conventional NC. Extensive simulation results demonstrated that DNC achieves high streaming continuity even in tight network conditions.

  20. A Secure Trust Model for P2P Systems Based on Trusted Computing

    HAO Li-ming; YANG Shu-tang; LU Song-nian; CHEN Gong-liang


    Trust is one of the most important security requirements in the design and implementation of peer-to-peer (P2P) systems. In an environment where peers' identity privacy is important, it may conflictwith trustworthiness that is based on the knowledge related to the peer's identity, while identity privacy is usually achieved by hiding such knowledge. A trust model based on trusted computing (TC) technology was proposed to enhance the identity privacy of peers during the trustworthiness evaluation process between peers from different groups. The simulation results show that, the model can be implemented in an efficient way, and when the degree of anonymity within group (DAWG) is up to 0.6 and the percentage of malicious peers is up to 70%, the service selection failure rate is less than 0.15.

  1. HitPeers: A P2P File Sharing System with Category Tree

    Jiang Shouxu(姜守旭); Liang Zhengqiang; Li Jianzhong


    HitPeers conotitute a scalable and highly efficient P2P file sharing system in which all the data file can be shared. The center of HitPeers is the Category Tree (CT). CT collects the published information with category. It is flexible enough to let users customize their own local CT. Its hierarchy helps users to find the information they desire most conveniently. To increase the robustness and retain the efficiency, HitPeers will divide the tree into disjoint parts. Every part is a subtree. Some special nodes named Onodes will take charge of the subtree and play the role of a service provider. HitPeers produce more and more Onodes to meet the service demands in the internet-scale distributed environment. This paper will show the profile of the whole system.

  2. Greedy-search based service location in P2P networks

    Zhu Cheng; Liu Zhong; Zhang Weiming; Yang Dongsheng


    A model is built to analyze the performance of service location based on greedy search in P2P networks. Hops and relative QoS index of the node found in a service location process are used to evaluate the performance as well as the probability of locating the top 5% nodes with highest QoS level. Both model and simulation results show that, the performance of greedy search based service location improves significantly with the increase of the average degree of the network. It is found that, if changes of both overlay topology and QoS level of nodes can be ignored during a location process, greedy-search based service location has high probability of finding the nodes with relatively high QoS in small number of hops in a big overlay network. Model extension under arbitrary network degree distribution is also studied.

  3. Securing the Distributions in P2P Networks with Trusted Platform Modules

    Hao Li


    Full Text Available We present a novel solution that allows one platform to securely distribute or redistribute digital contents to another in P2P networks. The solution includes three protocols (distribution protocol, usage protocol, redistribution protocol which are all based on platforms with Trusted Platform Modules (TPMs. It maintains the confidentiality and freshness of digital contents during the processes of distribution. Given an ideal (tamper-proof trusted platform, the solution can even withstand attacks by dishonest users during the processes of usage. Moreover, it can also be used to redistribute n-time-use digital content offline, so it is more flexible and scalable than other related distribution solutions to enable widespread deployment. Lastly, by adding a few simple features to TPMs, our solution can easily prevent the malicious sender and receiver from colluding when the redistribution takes place, so we can ensure that they can not gain more than a previously defined amount of rights without contacting the content provider.

  4. Algorithmic PON/P2P FTTH Access Network Design for CAPEX Minimization

    Papaefthimiou, Kostantinos; Tefera, Yonas; Mihylov, Dimitar


    Due to the emergence of high bandwidth-requiring services, telecommunication operators (telcos) are called to upgrade their fixed access network. In order to keep up with the competition, they must consider different optical access network solutions with Fiber To The Home (FTTH) as the prevailing...... one. It provides an obvious advantage for the end users in terms of high achievable data rates. On the other hand, the high initial deployment cost required exists as the heaviest impediment. The main goal of this paper is to study different approaches when designing a fiber access network. More...... concretely, two different optimizations are alternatively evaluated, fiber and trenching minimization, over two of the most typical fiber access architectures, Point-to-Point (P2P) and Passive Optical Network (PON). These are applied to a real geographical scenario and the best returned output in terms...

  5. Group Clustering Mechanism for P2P Large Scale Data Sharing Collaboration

    DENGQianni; LUXinda; CHENLi


    Research shows that P2P scientific collaboration network will exhibit small-world topology, as do a large number of social networks for which the same pattern has been documented. In this paper we propose a topology building protocol to benefit from the small world feature. We find that the idea of Freenet resembles the dynamic pattern of social interactions in scientific data sharing and the small world characteristic of Freenet is propitious to improve the file locating performance in scientificdata sharing. But the LRU (Least recently used) datas-tore cache replacement scheme of Freenet is not suitableto be used in scientific data sharing network. Based onthe group locality of scientific collaboration, we proposean enhanced group clustering cache replacement scheme.Simulation shows that this scheme improves the request hitratio dramatically while keeping the small average hops per successful request comparable to LRU.

  6. A Hybrid P2P Overlay Network for Non-strictly Hierarchically Categorized Content

    Wan, Yi; Asaka, Takuya; Takahashi, Tatsuro

    In P2P content distribution systems, there are many cases in which the content can be classified into hierarchically organized categories. In this paper, we propose a hybrid overlay network design suitable for such content called Pastry/NSHCC (Pastry for Non-Strictly Hierarchically Categorized Content). The semantic information of classification hierarchies of the content can be utilized regardless of whether they are in a strict tree structure or not. By doing so, the search scope can be restrained to any granularity, and the number of query messages also decreases while maintaining keyword searching availability. Through simulation, we showed that the proposed method provides better performance and lower overhead than unstructured overlays exploiting the same semantic information.

  7. SNMS: an intelligent transportation system network architecture based on WSN and P2P network

    LI Li; LIU Yuan-an; TANG Bi-hua


    With the development of city road networks, the question of how to obtain information about the roads is becoming more and more important. In this article, sensor network with mobile station (SNMS), a novel two-tiered intelligent transportation system (ITS) network architecture based on wireless sensor network (WSN) and peer-to-peer (P2P) network, is proposed to provide significant traffic information about the road and thereby, assist travelers to take optimum decisions when they are driving. A detailed explanation with regard to the strategy of each level as well as the design of two main components in the network, sensor unit (SU) and mobile station (MS), is presented. Finally, a representative scenario is described to display the operation of the system.

  8. A Semantic Searching Scheme in Heterogeneous Unstructured P2P Networks

    Jun-Cheng Huang; Xiu-Qi Li; and Jie Wu


    Semantic-based searching in peer-to-peer (P2P) networks has drawn significant attention recently.A number of semantic searching schemes,such as GES proposed by Zhu Y et al.,employ search models in Information Retrieval (IR).All these IR-based schemes use one vector to summarize semantic contents of all documents on a single node.For example,GES derives a node vector based on the IR model:VSM (Vector Space Model).A topology adaptation algorithm and a search protocol are then designed according to the similarity between node vectors of different nodes.Although the single semantic vector is suitable when the distribution of documents in each node is uniform,it may not be efficient when the distribution is diverse.When there are many categories of documents at each node,the node vector representation may be inaccurate.We extend the idea of GES and present a new class-based semantic searching scheme (CSS) specifically designed for unstructured P2P networks with heterogeneous single-node document collection.It makes use of a state-of-the-art data clustering algorithm,online spherical k-means clustering (OSKM),to cluster all documents on a node into several classes.Each class can be viewed as a virtual node.Virtual nodes are connected through virtual links.As a result,the class vector replaces the node vector and plays an important role in the class-based topology adaptation and search process.This makes CSS very efficient.Our simulation using the IR benchmark TREC collection demonstrates that CSS outperforms GES in terms of higher recall,higher precision,and lower search cost.

  9. Provide a New Model for Query Processing in P2P Integration Systems

    Hassan Shojaee Mend


    Full Text Available Most of organizations and companies meet their needs for software by providing distinguished software system during the time. Each one of these systems utilize own way for saving information which are not necessarily similar to other systems. Therefore, we are facing with a collection of information related to an organization which have been scattered in a series of heterogeneous databases. On the other hand, by the emergence of network and internet the number of existing and interrelated databases is increasing daily. The information must be extracted from this data sources. This task can be done through asking query about the information, but the combination of information from different data sources, due to different data structures, different schemas, different access protocols which they need and the distribution of data sources on the surface of network, is a hard and boring task. The purpose of integration systems is to provide an integrated query interface on a set of database, such a way that the user by using this integrated interface, without the need for knowing the location and the way of access to the data, can ask his query in the system and receive the existing results through the network. In this study, architecture has been provided for querying p2p integration system. In the suggested architecture, the features of a p2p environment and the changeability of the environment of the network have been considered. Also, the utilized mechanism for processing the query is such a way that to decrease the network traffic and the time of responding to the minimum. The practical results indicated that the suggested method has a close manner to the optimized status

  10. Characterizing Economic and Social Properties of Trust and Reputation Systems in P2P Environment

    Yu-Feng Wang; Yoshiaki Hori; Kouichi Sakurai


    Considering the fact that P2P (Peer-to-Peer) systems are self-organized and autonomous, social-control mechanism (like trust and reputation) is essential to evaluate the trustworthiness of participating peers and to combat the selfish, dishonest and malicious peer behaviors. So, naturally, we advocate that P2P systems that gradually act as an important information infrastructure should be multi-disciplinary research topic, and reflect certain features of our society. So, from economic and social perspective, this paper designs the incentive-compatible reputation feedback scheme based on well-known economic model, and characterizes the social features of trust network in terms of efficiency and cost. Specifically, our framework has two distinctive purposes: first, from high-level perspective, we argue trust system is a special kind of social network, and an accurate characterization of the structural properties of the network can be of fundamental importance to understand the dynamics of the system. Thus, inspired by the concept of weighted small-world, this paper proposes new measurements to characterize the social properties of trust system, that is, highg lobal and local efficiency, and low cost; then, from relative low-level perspective, we argue that reputation feedback is a special kind of information, and it is not free. So, based on economic model, VCG (Vickrey-Clarke-Grove)-like reputation remuneration mechanism is proposed to stimulate rational peers not only to provide reputation feedback, but truthfully offer feedback. Furthermore, considering that trust and reputation is subjective, we classify the trust into functional trust and referral trust, and extend the referral trust to include two factors: similarity and truthfulness, which can efficiently reduce the trust inference error. The preliminary simulation results show the benefits of our proposal and the emergence of certain social properties in trust network.

  11. Folksonomical P2P File Sharing Networks Using Vectorized KANSEI Information as Search Tags

    Ohnishi, Kei; Yoshida, Kaori; Oie, Yuji

    We present the concept of folksonomical peer-to-peer (P2P) file sharing networks that allow participants (peers) to freely assign structured search tags to files. These networks are similar to folksonomies in the present Web from the point of view that users assign search tags to information distributed over a network. As a concrete example, we consider an unstructured P2P network using vectorized Kansei (human sensitivity) information as structured search tags for file search. Vectorized Kansei information as search tags indicates what participants feel about their files and is assigned by the participant to each of their files. A search query also has the same form of search tags and indicates what participants want to feel about files that they will eventually obtain. A method that enables file search using vectorized Kansei information is the Kansei query-forwarding method, which probabilistically propagates a search query to peers that are likely to hold more files having search tags that are similar to the query. The similarity between the search query and the search tags is measured in terms of their dot product. The simulation experiments examine if the Kansei query-forwarding method can provide equal search performance for all peers in a network in which only the Kansei information and the tendency with respect to file collection are different among all of the peers. The simulation results show that the Kansei query forwarding method and a random-walk-based query forwarding method, for comparison, work effectively in different situations and are complementary. Furthermore, the Kansei query forwarding method is shown, through simulations, to be superior to or equal to the random-walk based one in terms of search speed.

  12. Analysis and Implementation of Gossip-Based P2P Streaming with Distributed Incentive Mechanisms for Peer Cooperation

    Sachin Agarwal


    contribute back to the P2P system, thus creating a powerful quality-of-service incentive for peers to contribute bandwidth to other peers. We propose a functional architecture and protocol format for a gossip-based streaming system with incentive mechanisms, and present evaluation data from a real implementation of a P2P streaming application.

  13. A Formal Communication Model for Lookup Operations in a Hypercube-based P2P Data Store

    Fahrenholtz, Dietrich; Wombacher, Andreas


    P2P data stores achieve high data availability by introducing replication of data. As a consequence, searching data may require to follow several routing paths introducing additional communication. A formal model of this additional communication is introduced and evaluated based on a hypercube-based P2P data store.

  14. E-learning



    难度:★★★☆☆词数:330建议阅读时间:6分钟Today e-learning or networked learning has beengaining more and more power;but there are still manyquestions concerning advantages and disadvantages ofgetting higher education online.E-learning has shown great advantages throughits accessibility(易接近,可获取) to all students nomatter where they are.E-classes help students to

  15. Structured P2P overlay of mobile brokers for realizing publish/subscribe communication in VANET.

    Pandey, Tulika; Garg, Deepak; Gore, Manoj Madhava


    Publish/subscribe communication paradigm provides asynchrony and decoupling, making it an elegant alternative for designing applications in distributed and dynamic environment such as vehicular ad hoc networks (VANETs). In this paradigm, the broker is the most important component that decouples other two components, namely, publisher and subscriber. Previous research efforts have either utilized the deployment of distributed brokers on stationary road side info-stations or have assigned the role of broker to any moving vehicle on ad hoc basis. In one approach, lots of preinstalled infrastructures are needed whereas, in another, the quality of service is not guaranteed due to unpredictable moving and stopping patterns of vehicles. In this paper, we present the architecture of distributed mobile brokers which are dynamically reconfigurable in the form of structured P2P overlay and act as rendezvous points for matching publications and subscriptions. We have taken city buses in urban settings to act as mobile brokers whereas other vehicles are considered to be in role of publishers and subscribers. These mobile brokers also assist in locating a vehicle for successful and timely transfer of notifications. We have performed an extensive simulation study to compare our approach with previously proposed approaches. Simulation results establish the applicability of our approach.

  16. Enhancing Scalability in On-Demand Video Streaming Services for P2P Systems

    R. Arockia Xavier Annie


    Full Text Available Recently, many video applications like video telephony, video conferencing, Video-on-Demand (VoD, and so forth have produced heterogeneous consumers in the Internet. In such a scenario, media servers play vital role when a large number of concurrent requests are sent by heterogeneous users. Moreover, the server and distributed client systems participating in the Internet communication have to provide suitable resources to heterogeneous users to meet their requirements satisfactorily. The challenges in providing suitable resources are to analyze the user service pattern, bandwidth and buffer availability, nature of applications used, and Quality of Service (QoS requirements for the heterogeneous users. Therefore, it is necessary to provide suitable techniques to handle these challenges. In this paper, we propose a framework for peer-to-peer- (P2P- based VoD service in order to provide effective video streaming. It consists of four functional modules, namely, Quality Preserving Multivariate Video Model (QPMVM for efficient server management, tracker for efficient peer management, heuristic-based content distribution, and light weight incentivized sharing mechanism. The first two of these modules are confined to a single entity of the framework while the other two are distributed across entities. Experimental results show that the proposed framework avoids overloading the server, increases the number of clients served, and does not compromise on QoS, irrespective of the fact that the expected framework is slightly reduced.

  17. A Distributed Architecture of Video Conference Using P2P Technology

    Xiaoyan Yu


    Full Text Available Most of the traditional video conferencing are standard SIP or H.323 architecture. There will be a single point of performance bottlenecks if large-scale video conference or a larger number of conferences emerge at the same time. In this paper, we proposed a new architecture of Multipoint Video Conference which can support a lot of meetings simultaneously using P2P and application multicast technology. In the side of server, the component called Media Control Server (MCS is responsible for the media data process and transmission path selection. All the MCSs form the MCS overlay. The capacity and conference state information of User Equipments (UE are stored in the MCS overlay. MCSs which be selected process all the transcoding and transmission task of audio and video for a meeting. In the side of user, some UEs which have enough bandwidth or other conditions could also undertake parts of media data process. MCS that service to the first UE in a conference decides which audio media process task could be assigned to Conference UEs; video media process task is allocated by Service MCS of video source. There are several methods to decide the transmission path, such as delay by server, application layer multicast or Hungarian method. At last, analysis is given to demonstrate the effectiveness of our architecture.

  18. Las simulaciones, una alternativa para el estudio de los protocolos P2P

    Armando de Jesús Ruiz Calderón


    Full Text Available La arquitectura y funcionalidad de las redes P2P hacen que sean atractivas para ser utilizadas en ambientes distribuidos locales y aplicaciones de amplia distribución, el análisis de sus protocolos de ruteo bajo diferentes ataques como son los de negación de existencia y de servicio, así como su análisis estadístico, hacen que las simulaciones cobren gran importancia, y sean una alternativa adecuada para su estudio, pues existen varios protocolos de esta categoría como Pastry o Chord, los cuales son de gran importancia dada su amplia utilización en diferentes aplicaciones para el envío y recuperación satisfactoria de información tanto en la nube como en aplicaciones distribuidas, razón por la cual su análisis es importante, este trabajo se centra en Pastry dado que es utilizado en la versión Azure de Microsoft Windows.


    Yukinobu Fukushima


    Full Text Available Minimum Physical Hop (MPH has been proposed as a peer selection algorithm for decreasing inter-AS (Autonomous System traffic volume in P2P live streaming. In MPH, a newly joining peer selects a peer whose physical hop count (i.e., the number of ASes traversed on the content delivery path from it is the minimum as its providing peer. However, MPH shows high inter-AS traffic volume when the number of joining peers is large. In this paper, we propose IMPH that tries to further decrease the inter-AS traffic volume by distributing peers with one logical hop count (i.e., the number of peers or origin streaming servers (OSSes traversed on the content delivery path from an OSS to the peer to many ASes and encouraging the following peers to find their providing peers within the same AS. Numerical examples show that IMPH achieves at the maximum of 64% lower inter-AS traffic volume than MPH.

  20. Towards an Effective Personalized Information Filter for P2P Based Focused Web Crawling

    Fu Xiang-hua


    Full Text Available Information access is one of the hottest topics of information society, which has become even more important since the advent of the Web, but nowadays the general Web search engines still have no ability to find correct and timely information for individuals. In this paper, we propose a Peer-to-Peer (P2P based decentralized focused Web crawling system called PeerBridge to provide user-centered, content-sensitive and personalized information search service from Web. The PeerBridge is built on the foundation of our previous work about WebBridge, which is a focused crawling system to crawl Web according several specified topic. The most important function of PeerBridge is to identify interesting information. So we furthermore present an efficient personalized information filter in detail, which combines several component neural networks to accomplish the filtering task. Performance evaluation in the experiments showed that PeerBridge is effective to crawl relevant information for specific topics and the information filter is efficient, which precision is better than that of support vector machine, naïve bayesian and individual neural network.

  1. Content subscribing mechanism in P2P streaming based on gamma distribution prediction


    P2P systems are categorized into tree-based and mesh-based systems according to their topologies. Mesh-based systems are considered more suitable for large-scale Internet applications, but require optimization on latency issue. This paper proposes a content subscribing mechanism (CSM) to eliminate unnecessary time delays during data relaying. A node can send content data to its neighbors as soon as it receives the data segment. No additional time is taken during the interactive stages prior to data segment transmission of streaming content.CSM consists of three steps. First, every node records its historical segments latency, and adopts gamma distribution, which possesses powerful expression ability, to express latency statistics. Second, a node predicts subscribing success ratio of every neighbor by comparing the gamma distribution parameters of the node and its neighbors before selecting a neighbor node to subscribe a data segment. The above steps would not increase latency as they are executed before the data segments are ready at the neighbor nodes. Finally, the node, which was subscribed to, sends the subscribed data segment to the subscriber immediately when it has the data segment. Experiments show that CSM significantly reduces the content data transmission latency.

  2. Removing bias due to finite measurement of dynamic systems: case study on P2P systems

    Benamara, Lamia


    Mesurer avec pr\\'ecision la dynamique des graphes de terrain est une t\\^ache difficile, car les propri\\'et\\'es observ\\'ees peuvent \\^etre biais\\'ees pour diff\\'erentes raisons, en particulier le fait que la p\\'eriode de mesure soit finie. Dans ce papier, nous introduisons une m\\'ethodologie g\\'en\\'erale qui nous permet de savoir si la fen\\^etre d'observation est suffisamment longue pour caract\\'eriser une propri\\'et\\'e donn\\'ee dans n'importe quel syst\\`eme dynamique. Nous appliquons cette m\\'ethodologie \\`a l'\\'etude des dur\\'ees de sessions et des dur\\'ees de vie des fichiers sur deux jeux de donn\\'ees P2P. Nous montrons que le comportement des propri\\'et\\'es est diff\\'erent : pour les dur\\'ees de sessions, notre m\\'ethodologie nous permet de caract\\'eriser avec pr\\'ecision la forme de leur distribution. Par contre, pour les dur\\'ees de vie des fichiers, nous montrons que cette propri\\'et\\'e ne peut pas \\^etre caract\\'eris\\'ee, soit parce qu'elle n'est pas stationnaire, soit parce que la dur\\'ee de notre me...

  3. A note on the data-driven capacity of P2P networks

    Chakareski, Jacob; Kerivin, Hervé; Leblet, Jimmy; Simon, Gwendal


    We consider two capacity problems in P2P networks. In the first one, the nodes have an infinite amount of data to send and the goal is to optimally allocate their uplink bandwidths such that the demands of every peer in terms of receiving data rate are met. We solve this problem through a mapping from a node-weighted graph featuring two labels per node to a max flow problem on an edge-weighted bipartite graph. In the second problem under consideration, the resource allocation is driven by the availability of the data resource that the peers are interested in sharing. That is a node cannot allocate its uplink resources unless it has data to transmit first. The problem of uplink bandwidth allocation is then equivalent to constructing a set of directed trees in the overlay such that the number of nodes receiving the data is maximized while the uplink capacities of the peers are not exceeded. We show that the problem is NP-complete, and provide a linear programming decomposition decoupling it into a master proble...

  4. A Comprehensive and Adaptive Trust Model for Large-Scale P2P Networks

    Xiao-Yong Li; Xiao-Lin Gui


    Based on human psychological cognitive behavior,a Comprehensive and Adaptive Trust(CAT) model for largescale P2P networks i8 proposed.Firstly,an adaptive trusted decision-making method based on HEW (Historical Evidences Window) is proposed,which can not only reduce the risk and improve system efficiency,but also solve the trust forecasting problem when the direct evidences are insufficient.Then,direct trust computing method based on IOWA(Induced Ordered Weighted Averaging)operator and feedback trust converging mechanism based on DTT(Direct Trust Tree)are set up,which makes the model have a better scalability than previous studies.At the same time,two new parameters,confidence factor and feedback factor,are introduced to assign the weights to direct trust and feedback trust adaptively,which overcomes the shortage of traditional method,in which the weights are assigned by subjective ways.Simulation results show that,compared to the existing approaches.the proposed model has remarkable enhancements in the accuracy of trust decision-making and has a better dynamic adaptation capability in handling various dynamic behaviors of peers.

  5. Structured P2P Overlay of Mobile Brokers for Realizing Publish/Subscribe Communication in VANET

    Pandey, Tulika; Garg, Deepak; Gore, Manoj Madhava


    Publish/subscribe communication paradigm provides asynchrony and decoupling, making it an elegant alternative for designing applications in distributed and dynamic environment such as vehicular ad hoc networks (VANETs). In this paradigm, the broker is the most important component that decouples other two components, namely, publisher and subscriber. Previous research efforts have either utilized the deployment of distributed brokers on stationary road side info-stations or have assigned the role of broker to any moving vehicle on ad hoc basis. In one approach, lots of preinstalled infrastructures are needed whereas, in another, the quality of service is not guaranteed due to unpredictable moving and stopping patterns of vehicles. In this paper, we present the architecture of distributed mobile brokers which are dynamically reconfigurable in the form of structured P2P overlay and act as rendezvous points for matching publications and subscriptions. We have taken city buses in urban settings to act as mobile brokers whereas other vehicles are considered to be in role of publishers and subscribers. These mobile brokers also assist in locating a vehicle for successful and timely transfer of notifications. We have performed an extensive simulation study to compare our approach with previously proposed approaches. Simulation results establish the applicability of our approach. PMID:24523629

  6. Structured P2P Overlay of Mobile Brokers for Realizing Publish/Subscribe Communication in VANET

    Tulika Pandey


    Full Text Available Publish/subscribe communication paradigm provides asynchrony and decoupling, making it an elegant alternative for designing applications in distributed and dynamic environment such as vehicular ad hoc networks (VANETs. In this paradigm, the broker is the most important component that decouples other two components, namely, publisher and subscriber. Previous research efforts have either utilized the deployment of distributed brokers on stationary road side info-stations or have assigned the role of broker to any moving vehicle on ad hoc basis. In one approach, lots of preinstalled infrastructures are needed whereas, in another, the quality of service is not guaranteed due to unpredictable moving and stopping patterns of vehicles. In this paper, we present the architecture of distributed mobile brokers which are dynamically reconfigurable in the form of structured P2P overlay and act as rendezvous points for matching publications and subscriptions. We have taken city buses in urban settings to act as mobile brokers whereas other vehicles are considered to be in role of publishers and subscribers. These mobile brokers also assist in locating a vehicle for successful and timely transfer of notifications. We have performed an extensive simulation study to compare our approach with previously proposed approaches. Simulation results establish the applicability of our approach.

  7. Coalition-based multimedia peer matching strategies for P2P networks

    Park, Hyunggon; van der Schaar, Mihaela


    In this paper, we consider the problem of matching users for multimedia transmission in peer-to-peer (P2P) networks and identify strategies for fair resource division among the matched multimedia peers. We propose a framework for coalition formation, which enables users to form a group of matched peers where they can interact cooperatively and negotiate resources based on their satisfaction with the coalition, determined by explicitly considering the peer's multimedia attributes. In addition, our proposed approach goes a step further by introducing the concept of marginal contribution, which is the value improvement of the coalition induced by an incoming peer. We show that the best way for a peer to select a coalition is to choose the coalition that provides the largest division of marginal contribution given a deployed value-division scheme. Moreover, we model the utility function by explicitly considering each peer's attributes as well as the cost for uploading content. To quantify the benefit that users derive from a coalition, we define the value of a coalition based on the total utility that all peers can achieve jointly in the coalition. Based on this definition of the coalition value, we use an axiomatic bargaining solution in order to fairly negotiate the value division of the upload bandwidth given each peer's attributes.

  8. 基于P2P的SIP网络研究%Research of SIP Internet based on P2P

    李桂林; 李建华



  9. 网贷模式的信用风险探析征信视角下 P2P%Lending Mode from Credit Reference Perspective An Analysis on Credit Risk for P2P Online

    王嵩青; 田芸; 沈霞


    近年来,我国 P2P 网络贷款作为互联网金融创新模式获得爆发式增长,但同时在信息不对称、征信主体权益保护等方面存在的信用风险问题也日益突出。为促进 P2P 网络贷款等互联网金融的发展,应加强征信管理与服务,将 P2P 网贷平台纳入征信管理范畴,强化 P2P 网贷平台信用管理和平台资金流动监管,加大网贷平台信用信息保护力度。%In recent years, as the Internet financial innovation mode, China’s P2P network loan has gained an ex-plosive growth. However, credit risk owing to information asymmetry and protection of the rights and interests of credit subjects is increasingly outstanding. In order to promote Internet financial development e. g. the P2P network lending, we should strengthen the credit reference management and service, classify the P2P online credit platform into the credit reference management, strengthen credit management of P2P online credit platform and supervision o-ver the liquidity of the platform, and take greater efforts on protecting credit information on the online lending plat-form.

  10. E-learning

    Safwan AL SALAIMEH


    Full Text Available E-learning means learning via electronic means and is therefore an all-embracing term covering learning via an electronic device. The "expectations" and "realities" for each of the delivery mechanisms within the electronic arena vary greatly for not just the learners themselves, but also the site providers [1]. Because of this, each of these learning systems has vastly different design principles, which is not always understood by those unfamiliar with technology. What is appropriate for a CD-ROM off-line system is generally inappropriate for an on-line internet system. So when designing an e-learning system it is important to understand how the information is to be accessed by the learner. This paper will identify and suggest some ways to avoid e-learning's pitfalls and reap its rewards.

  11. Rethinking e-learning

    Bang, Jørgen; Dalsgaard, Christian


    “Technology alone does not deliver educational success. It only becomes valuable in education if learners and teachers can do something useful with it” (E-Learning: The Partnership Challenge, 2001, p. 24). This quotation could be used as a bon mot for this chapter. Our main goal is to rethink e......-learning by shifting the focus of attention from learning resources (learning objects) to learning activities, which also implies a refocusing of the pedagogical discussion of the learning process.Firstly, we try to identify why e-learning has not been able to deliver the educational results as expected five years ago....... Secondly, we discuss the relation between learning objectives, learning resources and learning activities in an attempt to develop a consistent theoretical framework for learning as an active collaborative process, which bears social and cultural relevance for the student. Finally, we specify our concept...

  12. E-learning standards


    Full Text Available E-learning standards refer to a system of common rules for content, authoring software and Learning Management Systems (LMSs - rules that specify how courses can be created and delivered over multiple platforms so that they all operate seamlessly together. Accredited standards ensure that the investment in time and intellectual capital could move from one system to the next. Currently, e-learning standards are being developed by four main organizations: AICC, IEEE, IMS, and ADL. The article presents some aspects of these standards.

  13. Functions of a Computer Assisted Teaching Systems, SOLAR-CATS, which uses P2P technology

    山之上, 卓; ヤマノウエ, タカシ; Yamanoue, Takashi


    P2P技術を利用した教育支援システムSOLAR-CATSの機能について述べる。SOLAR-CATSを利用することにより、端末教室において、教師が行うSOLAR-CATSの応用プログラムの操作を、全学生端末上で、実時間で同時に見せたり、学生間で共同作業を行ったり、教師や学生が行う操作の記録と再生を行ったりすることができる。ファイヤーウォールで隔てられた遠隔地にある教室のネットワーク間を結んで利用することも可能である。SOLAR- CATSは、お絵かきプログラム、テキストエディタ、簡単なプログラミング環境、Webブラウザ、英作文支援システムなどの応用プログラムを備えている。 A computer assisted teaching system, SOLAR-CATS, which uses P2P technology, is shown. In a computer laboratory, the teacher can show operation of application programs of the SOLAR-CATS at his/her terminal ...

  14. Relay discovery and selection for large-scale P2P streaming.

    Zhang, Chengwei; Wang, Angela Yunxian; Hei, Xiaojun


    In peer-to-peer networks, application relays have been commonly used to provide various networking services. The service performance often improves significantly if a relay is selected appropriately based on its network location. In this paper, we studied the location-aware relay discovery and selection problem for large-scale P2P streaming networks. In these large-scale and dynamic overlays, it incurs significant communication and computation cost to discover a sufficiently large relay candidate set and further to select one relay with good performance. The network location can be measured directly or indirectly with the tradeoffs between timeliness, overhead and accuracy. Based on a measurement study and the associated error analysis, we demonstrate that indirect measurements, such as King and Internet Coordinate Systems (ICS), can only achieve a coarse estimation of peers' network location and those methods based on pure indirect measurements cannot lead to a good relay selection. We also demonstrate that there exists significant error amplification of the commonly used "best-out-of-K" selection methodology using three RTT data sets publicly available. We propose a two-phase approach to achieve efficient relay discovery and accurate relay selection. Indirect measurements are used to narrow down a small number of high-quality relay candidates and the final relay selection is refined based on direct probing. This two-phase approach enjoys an efficient implementation using the Distributed-Hash-Table (DHT). When the DHT is constructed, the node keys carry the location information and they are generated scalably using indirect measurements, such as the ICS coordinates. The relay discovery is achieved efficiently utilizing the DHT-based search. We evaluated various aspects of this DHT-based approach, including the DHT indexing procedure, key generation under peer churn and message costs.

  15. How P2P finance participates as the solution of SME financing difficulty in China: a case study


    Master in Business Administration SMEs finance difficulty has been a big problems in China for decades while significant solutions are still absent. However, in recent years, P2P finance appears as an innovation of financial industry, it has been widely accepted by the financial market worldwide. Its capability of connecting private capital to specific cash demand is considered as a powerful strength to solve many financial problems. Thus, the question how P2P finance would be as a solutio...

  16. Brief Announcement: Decentralized Construction of Multicast Trees Embedded into P2P Overlay Networks based on Virtual Geometric Coordinates

    Andreica, Mugurel Ionut; Sambotin, Ana-Delia; Tapus, Nicolae; 10.1145/1835698.1835766


    In this paper we consider the problem of efficiently constructing in a fully distributed manner multicast trees which are embedded into P2P overlays using virtual geometric node coordinates. We consider two objectives: to minimize the number of messages required for constructing a multicast tree by using the geometric properties of the P2P overlay, and to construct stable multicast trees when the lifetime durations of the peers are known.

  17. The Aggregation and Stability Analysis of Network Traffic for Structured-P2P-based Botnet Detection

    Zhitang Li


    Full Text Available Nowadays, botnets use peer-to-peer (P2P networks for command and control (C&C infrastructure. In contrast to traditional centralized-organized botnets, there is no central point of failure for structed-P2P-based botnets, which makes the botnets more concealable and robust and consequently degrades the botnet detection efficiency. In this work, an efficient structured-P2P-based botnet detection strategy through the aggregation and stability analysis of network traffic is proposed. Considering that the flows related to the structured-P2P-based bot exhibit stability on statistical meaning due to the impartial position in botnet and performing pre-programmed control activities automatically, we develop a stability detection subsystem to differentiate regular clients from bots. However, there may exist a large quantity of flows in supervised network, which makes botnet detection rather inefficient. Thus, a small flow-aggregation extraction subsystem is further developed to exclude a majority of flows unlikely for C&C communication of structured-P2P-based bots ahead of stability detection. Extensive experimental results show the proposed approach is very efficient and can detect structured-P2P-based botnet with low false positive ratio.

  18. Pervasive e-learning

    Helms, Niels Henrik; Hundebøl, Jesper


    The establishment of pervasive learning environments is based on the successful combination and re-configuration of inter-connected sets of activities and contexts. This chapter presents a definition of Pervasive (e) Learning Environments and discusses the pedagogical potentials and challenges...

  19. eLearning reconsidered

    Bang, Jørgen


    Looking back, the integration of the WWW in the Internet has been a success within almost every area of society: news distribution, public information, self-service, public relations, advertising, etc. Similar high expectations were also related to the introduction of e-learning in the educational...

  20. 大规模P2P TV会话时长与用户分类研究%Research on session length and user categorization in large scale P2P TV network

    姜志宏; 王晖; 李沛; 樊鹏翼


    P2P TV已经成为一种越来越普及的新型电视服务平台.与传统有线电视相比较,基于互联网的P2PTV在影响范围、交互性和开放性等方面都具有巨大的优势.P2P TV用户在感受到不同于传统电视的收看体验的同时,也表现出了不同于传统电视用户的收看行为.在利用自主研发的测量工具-TVCrawler获取实际系统数据的基础上,对P2P TV用户的会话时长进行了深入研究.按照P2P TV用户会话时长的分布特点,将其分为轻度收看者、中度收看者和重度收看者三类,对应的平均会话时长分别为3~5分钟,20~50分钟和120~200分钟,并进一步分析了在各被测频道中,三类用户各自的在线人数和到达率.%P2P TV system is getting more and more popular as a new TV service. In contrast with traditional cable and satellite TV system, the Internet-based P2P TV is more interactive, more open, and has wider sphere of influence. While getting some new experience that is different from traditional TV system, P2P TV users have exhibited some new characters of viewing behavior. In this work, it performs an in-depth study on session length of P2P TV user by analyzing the real data collected from the self-developed measuring tool named TVCrawler. According to the distribution characters of user session length, it puts P2P TV users into three categories: light viewers with 3~5 minutes of mean session length, medium viewers with 20~50 minutes of mean session length, and heavy viewers with 120-200 minutes of mean session length. It analyzes online number and arrival rate for different categories of users.

  1. Development Characteristics and Trend of China′s Current P2P Net Lending%当前我国 P2P 网络借贷的发展特征及趋势

    李显廷; 吴香萍


    The P2P net lending refers to loan through direct financing platform. In recent years,the suitable operation mode has been gradually explored,this reduced the individual and small micro financing cost,conformed to the inclusive financial concept,and with the popularity of the Internet and the mobile terminals,a new financial model P2P net lending attached to the network flourished. This article,by briefly analyzing the domestic and for-eign P2P net lending,and the development characteristics of net credit transaction data in 2014 based on the analy-sis of P2P net lending,expects its future development in China:the expansion of the scale,the price declination of the funds,the normalization of its development,the business transparency,the obvious trend of the trusteeship of the third party,and its difficulty of wiping out guarantee.%P2P 网络借贷是指借贷双方通过借贷平台进行直接融资。近年来,我国逐步探索出了适合本土发展的运营模式,降低了个人和小微融资成本,顺应了普惠金融的理念,随着互联网的普及和各移动端的广泛应用,使得依附于网络发展的新型金融模式 P2P 网络借贷势如破竹,蓬勃发展。本文首先对国内外 P2P 网络借贷做了简要分析,其次基于2014年的网贷交易数据分析 P2P 网络借贷的发展特征,最后对我国 P2P 网络借贷的未来发展做了展望:平台规模的扩大、借贷资金价格的下降、发展的规范化、经营的透明度化,平台资金的第三方托管趋势明显,去担保化暂难实现。

  2. 基于平衡多叉树的 P2P 网络拓扑研究%Research on P2P Network Topology Based on MBTN

    倪朔东; 袁蔚芳; 施佺


    In order to construct more efficient P2P network topology and improve the quality of service of P 2P network ,a novel topological architecture and scheduling algorithm based on multi‐balance tree networks in the application level are provided ,which node joining algorithm ,node exit algorithm ,and so on .Results of simulation experiment show that the method can effectively reduce the average recovery time and delay time and better reduce the control cost .%  为了进一步提高 P2P 网络的服务质量,构建性能更为优良的 P2P 网络,提出了一种新的基于平衡多叉树P2P 网络(MBTN)拓扑构建方案,对相关的调度算法进行了研究,并详细阐述了在该拓扑网络上节点加入和退出算法。最后,从节点平均恢复时间、平均延迟时间两方面对 MBTN 拓扑结构组播网络上的 P2P 业务进行仿真试验。实验表明,基于 MBTN 仿真出的拓扑网络可以有效减少节点恢复时间和延迟时间,较好地降低了控制成本。

  3. 我国 P2P 网络借贷规范化发展的法制建设探讨%On the legal System Construction of P2P Network Lending System in China



    P2 P网络借贷是实现国家普惠金融战略的重要手段。为了规范化我国P2 P网络借贷的发展,对P2 P业务暴露出的法律风险进行了探讨。首先分析了我国P2 P网络借贷发展过程中暴露出的法律风险,在此基础上介绍了美国对P2 P网络借鉴业务的立法与监管。针对我国P2 P存在的法律问题,在借鉴美国经验的基础上给出了我国P2 P网络借贷规范化发展的法制建设对策。%P2P network lending system is an important means to achieve national inclusive financial strategy .In order to stand-ardize the development of P2P network lending system in China , the legal risks of P2P business exposure were discussed in this pa-per and the legal risks exposed in the development of P 2P network in China as well .The paper also introduces the legislation and regulation of the United States in view of the legal problems existing in China's P2P lending system.Some measures to construct the legal system of P2P network lending and standardize its development in our country are given based on the experience of the United States.

  4. 中国 P2P 网络借贷平台的征信问题研究%Research on Credit Information of P2P Network Lending Platform in China



    P2P network lending refers to micro-finance lending demand side and the supply side of funds on the Internet.It is a new Internet business model.Since the birth of the loan in 2007,the loan of P2P network platform in the past five years has experienced rapid development stage .But due to lack of credit model has been raised more risk events,and seriously affect their sustainable development.In this pa-per,based on the P2P net loan platform development status and mode of operation as a starting point,in terms of its credit analysis of the problems and put forward reasonable suggestions from the technical and legal aspects.%P2P 网络借贷是指资金的需求方和供给方在互联网上进行的小额资金借贷,是一种新兴的互联网商业模式。自2007年拍拍贷诞生之后,我国 P2P 网贷平台在过去5年经历了高速发展阶段,但因征信模式缺失已引发较多风险事件,并严重影响其可持续发展。以我国 P2P 网贷平台的发展现状和运作模式为出发点,对其在征信方面存在的问题进行剖析,并从技术层面和法律层面提出政策建议。

  5. A Replica Placement Game Model for P2P Storage%一种 P2P 存储下的副本放置博弈模型*

    宋玮; 朱兵章


      Replica balance in P2P storage system will affect usability greatly. Considering selfishness of peers, designs game model of P2P storage system. By using simple equilibrium achieving algo-rithm and effective P2P overlay network routing structure, designs game initiating and mainte-nance mechanism, which makes sure of balance in replica distribution. This model can bring great advantages of scalability, decentralized control and reliability and provide new solution for increasing demands on data storage.%  对等网络存储系统中副本的均衡性将影响的系统的可用性。考虑对等节点在放置数据副本时的自私性,建立 P2P 存储下的博弈模型,采用简单的博弈获取均衡算法,并借助 P2P 覆盖网络有效的路由结构与更新算法,设计博弈的发起及维护机制。模型保证数据副本在对等节点间的均衡分布,使 P2P 存储系统具有由良好的扩展性,分散控制和可靠性,为日益增长的数据存储需求提供新的解决方案。


    Adhitya Nugraha


    Full Text Available Sejak kemunculan peer-to-peer (P2P Command and Control (C&C arsitektur, botnet menjadi lebih kuat dibandingkan sebelumnya. Identifikasi anomali dari P2P botnet sangatlah sulit dilakukan padahal proses tersebut merupakan langkah awal yang sangat penting untuk mengidentifikasi kemungkinan adanya potensi ancaman dari malicious bot dalam jaringan. Hal ini menjadi sulit dikarenakan beberapa perilaku dari fitur botnet sangatlah mirip dengan aktifitas jaringan yang sah.Tujuan dari penelitian ini adalah menemukan anomali yang disebabkan oleh peer to peer (P2P botnets menggunakan metode PCA. Sebagai tambahan, Euclidean distance digunakan untuk mengkalkulasi anomali indeks sebagai parameter pengukuran dari anomali dalam jaringan. Threshold ditetapkan berdasarkan perhitungan pada training set. Setiap pengujian atas sampel test data akan dibandingkan dengan threshold. Apabila hasil kalkulasi test data berada diatas nilai threshold, maka ini menandakan adanya kemungkinan perilaku abnormal pada jaringan. Hasil menunjukan bahwa model kami mampu memberikan akurasi dan efisiensi komputasi dalam mendeteksi perilaku abnormal dari P2P botnet. Kata kunci: botnet, P2P Command and Control, deteksi anomali, PCA

  7. A QoS-Aware Service Selection Approach on P2P Network for Dynamic Cross-Organizational Workflow Development

    Zhou, Jielong; Dou, Wanchun

    A workflow system is often composed of a number of subtasks in its pattern. In services computing environment, a dynamic cross-organizational workflow can be implemented by assigning services to its subtasks. It is often enabled by a service discovery process on Internet. Traditional service discovery approaches are centralized, and suffer from many problems such as one-point failure and weak scalability. Thus, decentralized P2P technique is a promising approach for service publishing and discovery. It is quite probable that there are more than one candidates which have exactly the same function after a service discovery process. It is often a challenging effort to select a qualified service from a group of candidates, especially on P2P networks. In view of this challenge, a QoS-aware service selection approach on unstructured P2P networks is presented in this paper. It aims at discovering and selecting services on two-layered unstructured P2P networks according to QoS parameters of services and preference of service requesters. This approach is applied to a case study based on a simplified P2P network with some virtual services.

  8. Evolutionary Game Theory-Based Evaluation of P2P File-Sharing Systems in Heterogeneous Environments

    Yusuke Matsuda


    Full Text Available Peer-to-Peer (P2P file sharing is one of key technologies for achieving attractive P2P multimedia social networking. In P2P file-sharing systems, file availability is improved by cooperative users who cache and share files. Note that file caching carries costs such as storage consumption and processing load. In addition, users have different degrees of cooperativity in file caching and they are in different surrounding environments arising from the topological structure of P2P networks. With evolutionary game theory, this paper evaluates the performance of P2P file sharing systems in such heterogeneous environments. Using micro-macro dynamics, we analyze the impact of the heterogeneity of user selfishness on the file availability and system stability. Further, through simulation experiments with agent-based dynamics, we reveal how other aspects, for example, synchronization among nodes and topological structure, affect the system performance. Both analytical and simulation results show that the environmental heterogeneity contributes to the file availability and system stability.

  9. Accessible e-learning

    Bühler, Christian; Scheer, Birgit


    People with disabilities often encounter difficulties while trying to learn something, because teaching material is for example not accessible to blind people or rooms, where courses take place, are not accessible to people using a wheelchair. E-learning provides an opportunity to disabled people. With the new German law on the equalisation of opportunities for people with disabilities for the first time access to information technology was explicitly taken up in German legislation. As a cons...

  10. 从P2P本质特征视角对P2P发展愿景的研究%The Research on P2P Development Vision from the Perspective of the Nature of P2P

    陆岷峰; 李琴


    关于P2P,从产生到爆发性成长其争论之声从没停止过,由于对其认识上的不统一,导致对P2P的评价不一致,其发展目标、社会认同、成长方式及未来愿景也各不相同。从P2P本质特征分析入手,掌握P2P的基本特征,便于抓住事物的本质和主要矛盾,从而对P2P未来的发展前景作出科学的判断,对保持这一新生事物的发展才能提供一个良好的环境。 P2P其特征有本质和非本质之分,本质特征是“互联网+民间借贷”,非本质特征有互联网金融、信用中介、民间借贷等,P2P的本质特征已经充分表明其有美好的发展愿景,P2P有着巨大的需求市场和广泛的供给市场,同时也适应了金融市场多元化需求的大的发展趋势,现实中存在的问题是当前P2P所面临的监管、信任机制等不完善造成的,这并不否定P2P生命力及生存发展的本身。%The argument about P2P has never stopped from P2P’ emergence to its rapid growth. The different understanding to P2P leads to the different evaluation on P2P, and its development goals, social recognition, growth methods and future vision are also different. From the analysis on the nature of P2P, the paper thinks that mastering the basic features of P2P means mastering the essence and the principal contradiction of P2P, therefore the scientific judgment can be made on the development vision of P2P in the future, and a good environment can be provided to keep the development of the new-born thing. P2P is characterized with essential nature and non-essential nature, and its essential nature is“Internet+informal lending”, while the non-essential nature includes the Internet fi-nance, credit intermediary, informal lending etc. The essential nature of P2P has fully shown that P2P has a good development vision, has a huge market demand and a wide range of market supply, and has adapted to the development trend of the diversified

  11. An Efficient Encryption Algorithm for P2P Networks Robust Against Man-in-the-Middle Adversary

    Roohallah Rastaghi


    Full Text Available Peer-to-peer (P2P networks have become popular as a new paradigm for information exchange and are being used in many applications such as file sharing, distributed computing, video conference, VoIP, radio and TV broadcasting. This popularity comes with security implications and vulnerabilities that need to be addressed. Especially duo to direct communication between two end nodes in P2P networks, these networks are potentially vulnerable to Man-in-the-Middle attacks. In this paper, we propose a new public-key cryptosystem for P2P networks that is robust against Man-in-the-Middle adversary. This cryptosystem is based on RSA and knapsack problems. Our precoding-based algorithm uses knapsack problem for performing permutation and padding random data to the message. We show that comparing to other proposed cryptosystems, our algorithm is more efficient and it is fully secure against an active adversary.

  12. Selección de los mejores peers servidores en un sistema P2P-VoD

    Ilabaca, Cristian; Balladini, Javier; Suppi, Remo


    La mayoría de los sistemas peer-to-peer (P2P) de video bajo demanda (VoD, Video-on-Demand) no consideran cuidadosamente todos los problemas que pueden surgir al desplegar sus servicios en una red con alta probabilidad de fallos como Internet. El resultado es que ellos no pueden garantizar servicios de visualización de videos libres de interrupciones. De esta manera, hemos propuesto previamente un esquema de tolerancia a fallos fácilmente adaptable a los sistemas P2P-VoD ya desarrollados. C...

  13. An Effective Interval-Valued Intuitionistic Fuzzy Entropy to Evaluate Entrepreneurship Orientation of Online P2P Lending Platforms

    Xiaohong Chen


    Full Text Available This paper describes an approach to measure the entrepreneurship orientation of online P2P lending platforms. The limitations of existing methods for calculating entropy of interval-valued intuitionistic fuzzy sets (IVIFSs are significantly improved by a new entropy measure of IVIFS considered in this paper, and then the essential properties of the proposed entropy are introduced. Moreover, an evaluation procedure is proposed to measure entrepreneurship orientation of online P2P lending platforms. Finally, a case is used to demonstrate the effectiveness of this method.

  14. P2P TV在线用户的时空分布研究%Research on temporal and spatial distribution of online users in P2P TV

    姜志宏; 王晖; 黄兵; 李沛; 樊鹏翼


    Direct towards anonymity and high dynamic of online user in P2P TV, a P2P TV crawler, called TVCrawler was developed and deployed which enabled to launch an active measurement on several popular large scale P2P TV systems. The authors conducted a comparative research on time evolution and geographic distribution of online users in these different P2P TV systems. First, while intuitively researching the time evolution of online users in P2P TV channel, the method of MultiScale Entropy (MSE) analysis was introduced to investigate the complexity in time series of the number of online users. Second, the authors made a study on the regular pattern of online users' geographic distribution, and made a Google map-based visual representation about online users. Then, by analyzing the relationship between geographic distribution of online Chinese users and provincial economic development level of China, it is discovered that significant linear decreasing correlation exists between the two of them.%针对P2PTV在线用户的匿名性和高度动态性,设计和部署了P2P TV爬行器-TVCrawler对主流的大规模P2P IPTV系统进行主动测量,对比研究了不同P2PTV系统中在线人数的时间演化和地理分布规律.首先,对在线用户数量的在时间上的演化规律进行了直观分析,并通过多尺度熵方法研究了在线用户人数时间序列的复杂性;其次,研究了在线用户在地理空间分布上的分布特点和规律,并对用户的地理分布进行了可视化展现;最后还研究了各省级行政区内的频道在线用户与当地经济发展水平的关系,发现二者之间存在较为显著的线性递减关系.

  15. Auction based bandwidth allocation mechanism for P2P content distribution networks%基于拍卖的 P2P 内容分发网络带宽分配机制

    张云鹤; 朱艳琴; 纪其进


    Unreasonable allocation of originally scarce bandwidth was a severe problem in the P2P content distribution networks. To solve the problem and suppress the node’s selfishness, an auction-based bandwidth allocation mechanism for P2P networks was proposed. Through the effective bandwidth payment scheme, the selfish nodes had no incentives to lie and provided the real bandwidth requirements. Also the “tragedy of the commons” could be avoided by the nodes’ healthy bandwidth competition. To adapt to the distributed nature of the P2P networks, the algorithm was implemented in parallel at resource providing nodes and request nodes. Simulation results show that the scheme not only suppresses free riding nodes efficiently in the system, but also shortens the average completion time for content distribution and decreas-es the ratio of data uploaded by the source server.%  为了解决 P2P 内容分发网络中带宽资源稀缺且分配不合理这一突出问题,抑制节点的自私性行为,设计了一种基于拍卖的带宽分配机制。该机制通过上载带宽支付方式,迫使自私请求节点选择合适的带宽需求,使得整个 P2P 网络中的节点良性竞争带宽资源,避免了“公共地悲剧”的发生;且带宽分配算法在资源节点和请求节点并行执行,能很好适应 P2P 网络的分布式特性。仿真结果表明,该机制能够有效遏制搭便车行为,从而缩短P2P 内容分发的平均完成时间,降低内容源服务器的上传数据比例。

  16. Hybrid ants-like search algorithms for P2P media streaming distribution in ad hoc networks


    Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions, potential high loss rate and the decentralized architecture. To support long and high-quality streams, one viable approach is that a media stream is partitioned into segments, and then the segments are replicated in a network and served in a peer-to-peer (P2P)fashion. However, the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm (HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks, such as low transmitting latency, less jitter times, and low unnecessary traffic. We quantify the performance of our scheme in terms of response time, jitter times, and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks.

  17. StreetTiVo: Using a P2P XML Database System to Manage Multimedia Data in Your Living Room

    Y. Zhang (Ying); A.P. de Vries (Arjen); P.A. Boncz (Peter); D. Hiemstra; R. Ordelman


    textabstractStreetTiVo is a project that aims at bringing research results into the living room; in particular, a mix of current results in the areas of Peer-to-Peer XML Database Management System (P2P XDBMS), advanced multimedia analysis techniques, and advanced information retrieval techniques. Th

  18. A Formal Communication Model for Lookup Operations in a Hypercube-based P2P Data Store

    Fahrenholtz, Dietrich; Wombacher, Andreas


    P2P data stores achieve high data availability by introducing replication of data. As a consequence, searching data may require to follow several routing paths introducing additional communication. A formal model of this additional communication is introduced and evaluated based on a hypercube-based

  19. CORS TV:一种基于网络编码的P2P TV系统%CORS TV:A Network Coding Based P2P TV System

    张志明; 杜剑; 郭瑛; 周晋; 陈震; 李军


    Network coding can achieve maximum throughput of multicast, which shows the potential to decrease playback delay of users in P2P TV system, to improve delivery ratio, and therefore to improve video quality of the whole system. In order to improve the performance of the P2P TV system,a system based on Random Linear Nework Coding (RLNC) .called CORS TV,was designed and implemented with carefully designed topology construction and data transmission. Full taking advantage of network coding and further improving the performance of P2P TV,CORS TV has a modular architecture,and each function module runs an independent thread. The system integrates Gossip protocol for topology construction,uses most-first algorithm for determining initial playback point, and employs push based transmission scheme with First Come First Served(FCFS) transmission algorithm. The experiment results validate the effectiveness of the CORS TV desiga Compared with current P2P TV systems, it has the advantages of lower redundancy ratio,higher delivery ratio and better playback quality of users.%网络编码可以实现组播的最大吞吐率,若应用于P2P TV系统,具有降低用户播放延时、提高系统有效传输率,从而提高视频质量的潜力.为了提高P2P TV系统的性能,设计并实现了一个基于随机线性网络编码的P2P TV系统——CORS TV.围绕拓扑构建和数据传输这两个关键部分,充分利用网络编码提高系统性能,CORS TV具有功能模块线程隔离的节点内部结构,集成了基于Gossip协议的拓扑构建算法,使用了最多者优先的初始播放点设置算法,并利用了基于推的数据传榆方案和先到先得式的数据传输算法.在计算机集群上的实验验证了CORS TV系统设计的正确性和有效性.与已有P2P TV系统相比,该系统具有降低冗余率、提升系统的有效传输率、改善用户视频播放质量的优势.

  20. Traffic statistics-based identification of key nodes in P2P network%基于流量统计的 P2P 网络关键节点识别

    王晓磊; 杨岳湘; 何杰


    针对当前 P2P(peer-to-peer)网络普遍存在关键节点的现状,为了准确地识别 P2P 网络中的关键节点,通过分析关键节点的相应特点,提出了一种基于网络流量的 P2P 关键节点识别方法。通过提取网络流的空间特征等特性作为关键节点识别的依据,并以 Skype 作为研究对象,采用真实的流量数据进行验证测试。实验表明,该方法能够准确地识别出 Skype 网络中的关键节点,识别准确率较高,而且实时性较好。%In accordance with the prevalence of key nodes in P2P network,this paper analyzed the corresponding characteris-tics of key nodes and proposed a network-based novel to identify the key nodes in P2P network.It extracted the time and space characteristics of network flow as the basis for identifying key nodes.It selected the Skype as the research object and used real traffic data to verify and test.Experiment results show that the method can accurately identify the Skype key nodes in the net-work with the higher recognition accuracy and better real-time.

  1. Study on the Formation Mechanism for P2P Herding Effectin China and the Countermeasures%我国 P2P 羊群效应形成机制与破解对策研究

    李新功; 刘扬帆


    互联网为基础的 P2P 网络借贷便利了借贷双方,但也容易造成网络借贷的逆向选择,即形成网络借贷的“羊群效应”。基于“人人贷”公布的不同借款者的借款数据,构建 logistic 回归模型,研究当前投标次数对后期投标可能带来的影响,验证 P2P 网络借贷平台“羊群效应”的存在。探究“羊群效应”形成机制和影响因素,并提出完善征信体制、明确监管主体、加强行业自律等破解对策。%The Internet-based P2P online lending facilitates both sides of borrowers and lenders, but it is easy to cause the adverse selection of online lending, i. e. forming online lending “herding effect”. Based on the loan data of different borrowers obtained from “ Renrendai. com”, the logistic regression model is constructed to study the impact of current bid on the following bid, and to verify the existence of the “herding effect” of the P2P online lending platform. Based on exploring the formation mechanism and the influencing factors of the “herding effect”, the paper proposes such countermeasures as improving the credit reference regime, specifying the regulatory body, and strengthening the industry self-regulation.


    甘露; 姜秀艳; 刘新; 叶德建


    随着IPTV的迅速发展和用户量的激增,现有IPTV采用的纯CDN网络架构扩展性较差,在花销上需要付出很大代价.针对该问题,详细探讨了在电信现网条件下实施机顶盒P2P的可行性,以及影响P2P效果的因素,主要包括上传速率与节目码流的比值以及P2P策略和机制的选择这两个要点.对大量的IPTV用户数据进行了特征分析,得到了一些值得IPTV P2P相关研究可以参考的统计结果.%Nowadays, with the rapid development of IPTV and the sharp increase in subscribers, the pure CDN architecture adopted by existing IPTV has showed its limitation in expansion, and needs to pay a lot to expand their service scale. In light of this, in the paper we elaborately discuss the feasibility of implementing set-top box P2P in condition of CDN at Shanghai Telecom, and find out the factors that impacts the effect of P2P, mainly including two key factors; the ratio of upload speed and bit rate, and the selection of P2P strategy and mechanism. We have done the behaviour characteristics analysis based on huge number of IPTV user data of Shanghai Telecom, the statistic results attained might be helpful for other IPTV P2P researches.

  3. P2P Web搜索中一种有效的查询路由策略%An Effective Query Routing Strategy over P2P Web Search

    王振华; 李妹芳; 申德荣; 于戈


    Effective multi-keyword query routing is the key problem over P2P Web search. A novel query processing strategy based on benefit cost ratio was proposed A P2P overlay based on DHT has been built, and take into account of the correlation of keywords as well as the coverage and overlap among peers. Min-wise independent permutation was applied for overlap detection, so the redundant routing to the same result is avoided. The experimental results show that the method improves the search performance greatly.%有效的多关键字查询路由是P2P Web搜索中的一个关键问题.文章提出一种基于收益代价比的查询处理方法.该方法基于DHT的P2P覆盖网,挖掘关键字的关联性和节点间覆盖度和重叠度.利用最小独立置换进行重叠检测,因此避免了对相同记录的冗余路由.实验证明了该方法显著减少了查询时间,同时提高了查全率和查准率.

  4. Survey on P2P Network Pollutions%P2P网络数据污染综述

    王勇; 云晓春; 秦志光; 郭莉; 程红蓉


    In recent years,the security issues of Peer-to-Peer networking applications(P2P) are becoming the hot spots of network security research.The pollution and poisoning problems of shared content in P2P network present a new challenge for P2P networking security:such as how to find and locate the polluted data,how to modeling the pollution and poisoning process, and how to prevent the spreads of polluted contents efficiently etc.In this paper, the up-to-date researching results were discussed in detail from the three main angles as the polluted data measurements, the modeling processes, and the pollution constrain strategies; some key issues related to P2P network pollutions were analyzed.Finally, the paper pointed out the future possible researching trends on P2P network pollutions.%对等网络应用(Peer-to-Peer networking applications,P2P)相关的安全威胁已经成为广受关注的网络安全课题.P2P网络共享文件内容的数据污染给P2P网络安全带来新的难题:例如,如何快速定位发现污染数据,分析污染数据特征模型,寻求高效低代价的数据污染治理策略等还有待进一步深入分析研究.针对P2P网络数据污染,从污染数据监测、数据污染特征模型分析以及数据污染治理策略等三方面,阐述了当前该邻域的主要研究动态,分析了数据污染相关研究的关键问题,最后指明了该邻域未来可能的发展方向.

  5. 一种基于bot优先抽样的P2P botnet在线检测技术%Bot priority sampling based P2P botnet online detection technique

    李华波; 胡谷雨; 杨云; 赖海光


    Botnets pose a steady and growing threat to network security and have become one of the most significant threats to the Internet. Using highly efficient and flexible one-to-many control mechanisms, botnets provide a infrastructure of reserves, management and use of cyber attack capabilities. To meet the instant detection requirements of P2P botnets on high-speed networks, a bot priority sampling based online detection technique was presented. In order to efficiently use as many as possible the limited computing resources and sample packets of suspicious P2P bots, a bot priority classification algorithm and a priority-based sampling algorithm were proposed. Flow information recovering and flow cluster analyzing approaches were used to identify the suspicious P2P bots based on the sampled packets. The experimental evaluation results show that the proposed technique can increase the sampling rates packets from P2P botnets traffic subpopulations and has a good sampling efficiency and P2P bots detection hit rate.%僵尸网络利用高效灵活的一对多控制机制,为攻击者提供了储备、管理和使用网络攻击能力的基础架构和平台,已成为当前Internet最严重且持续增长的安全威胁之一.为满足在高速网络实时检测P2P僵尸网络的需求,提出了一种基于bot优先抽样的在线检测技术.该方法利用bot优先的分级算法和基于优先级的包抽样算法,使得检测系统能够高效利用计算资源,在整体抽样率有限条件下,优先对疑似P2P僵尸通信数据包进行抽样,并使用流信息重构技术和流簇分析技术对抽样包进行统计分析来发现P2P僵尸主机.实验结果表明,所提出的在线检测技术能够有效提高对疑似P2P僵尸网络流量亚群的包抽样率,具有良好的在线检测效率和P2P僵尸检测命中率.

  6. KaZaA and similar Peer-to-Peer (P2P) file-sharing applications


    Personal use of Peer-to-Peer (P2P) file sharing applications is NOT permitted at CERN. A non-exhaustive list of such applications, popular for exchanging music, videos, software etc, is: KaZaA, Napster, Gnutella, Edonkey2000, Napigator, Limewire, Bearshare, WinMX, Aimster, Morpheus, BitTorrent, ... You are reminded that use of CERN's Computing Facilities is governed by CERN's Computing Rules (Operational Circular No 5). They require that all users of CERN's Computing Facilities respect copyright, license and confidentiality agreements for data of any form (software, music, videos, etc). Sanctions are applicable in case of non-respect of the Computing Rules. Further details on restrictions for P2P applications are at: CERN's Computing Rules are at: Denise Heagerty, CERN Computer Security Officer,

  7. E-Learning in Architecture

    Juvancic, Matevz; Mullins, Michael; Zupancic, Tadeja


    E-learning in architectural and spatially related fields can be examined from two different perspectives, each having quite specific and complex implications. By discussing e-learning in architecture we inspect the scope of e-learning tools and practices within the architectural domain, the visual...... nature of education and professional training of architects, and the state of the art of e-learning implementations, together with their practicality and limitations. While these are the first areas that come to mind when considering e-learning in relation to architecture, there is another also very...... relevant and sometimes overlooked aspect: that of e-learning about architecture. In the latter, we introduce not only the professional but also the broader, non-expert public into the process of acting within, and shaping of, their spatial environments. This aspect raises burning questions regarding...

  8. Temporal Patterns of Pedophile Activity in a P2P Network: First Insights about User Profiles from Big Data

    Fournier, Raphaël; Latapy, Matthieu


    International audience; Recent studies have shown that child abuse material is shared through peer-to-peer (P2P) networks, which allow users to exchange files without a central server. Obtaining knowledge on the extent of this activity has major consequences for child protection, policy making and Internet regulation. Previous works have developed tools and analyses to provide overall figures in temporally-limited measurements. Offenders' behavior is mostly studied through small-scale intervi...

  9. A Fuzzy Search Algorithm for Structured P2P Network Based on Multi-dimensional Semantic Matrix

    Chuiwei Lu


    Full Text Available Structured P2P network is highly efficient and low cost in resources search, but it only supports single-keyword precise search rather than multi-keyword fuzzy search. This paper puts forward a novel search algorithm FSA-MDSM based on semantic vector matrix, in which the P2P node resources can be transferred into a number of semantic vectors which are formed into a vector matrix in terms of a free semantic dictionary. And according to the similarity of vectors semantics, the vectors are classified into several sub-blocks, each of which is managed by a virtual node. Those virtual nodes with similar semantics will cluster into several special subnets by the way of exchange of the semantic information, and a semantics routing table will be generated. The table can guide a node to locate target resource rapidly. The simulation experiments demonstrate that by using FSA-MDSM algorithm, a fuzzy semantic search can be supported efficiently in the Structured P2P network and its original advantage can not be lost basically

  10. JXME: Una plataforma robusta para el desarrollo de aplicaciones P2P en dispositivos móviles

    Francisco Orlando Martínez Pabón


    Full Text Available Paralelamente a la gran difusión de las tecnologías P2P, los dispositivos móviles, principalmente teléfonos celulares, PDAs y smartphones, se convierten en la gran ola de dispositivos conectados a Internet de nueva generación. Siguiendo esta tendencia, Sun Microsystems lanzó el proyecto JXTA, un conjunto de APIs y protocolos para el desarrollo de aplicaciones P2P, y posteriormente una especialización del mismo para dispositivos móviles conocida como JXME. Este artículo describe el trabajo realizado por el Grupo de Interés en el Desarrollo de Aplicaciones Móviles e Inalámbricas – W@PColombia, perteneciente al Grupo de Ingeniería Telemática de la Universidad del Cauca, acerca del desarrollo de aplicaciones P2P para dispositivos móviles con JXME. A través de un prototipo de validación conocido como Punto de Encuentro Virtual Móvil se logró comprobar la viabilidad de este tipo de aplicaciones en la redes de 2.5G y se realizaron aportes importantes al trabajo desarrollado por la comunidad JXTA.

  11. The Comparison of Distributed P2P Trust Models Based on Quantitative Parameters in the File Downloading Scenarios

    Jingpei Wang


    Full Text Available Varied P2P trust models have been proposed recently; it is necessary to develop an effective method to evaluate these trust models to resolve the commonalities (guiding the newly generated trust models in theory and individuality (assisting a decision maker in choosing an optimal trust model to implement in specific context issues. A new method for analyzing and comparing P2P trust models based on hierarchical parameters quantization in the file downloading scenarios is proposed in this paper. Several parameters are extracted from the functional attributes and quality feature of trust relationship, as well as requirements from the specific network context and the evaluators. Several distributed P2P trust models are analyzed quantitatively with extracted parameters modeled into a hierarchical model. The fuzzy inferring method is applied to the hierarchical modeling of parameters to fuse the evaluated values of the candidate trust models, and then the relative optimal one is selected based on the sorted overall quantitative values. Finally, analyses and simulation are performed. The results show that the proposed method is reasonable and effective compared with the previous algorithms.

  12. Approaches to e-learning

    Hartvig, Susanne Akrawi; Petersson, Eva


    between recognition and learning will enable an optimization of the learning conditions and the interactive affordances targeting students under e-learning programs. The paper concludes that the engagement and motivation to learn are not only influenced by but depending on recognition.......E-learning has made its entrance into educational institutions. Compared to traditional learning methods, e-learning has the benefit of enabling educational institutions to attract more students. E-learning not only opens up for an increased enrollment, it also gives students who would otherwise...

  13. P2P在线视频研究综述%Survey on P2P video streaming systems

    李真真; 张志斌; 杜跃进


    P2P技术凭借其开放性、可扩展性和高性价比等优点成为了目前解决在线视频问题的有效手段之一.虽然P2P技术在文件共享和IP语音等方面的应用已经基本趋于成熟,但其在在线视频领域的应用尚处于起步阶段,还面临着许多需要解决的问题.对P2P在线视频进行了全面而深入的分析,首先介绍了网络广播分类及体系结构设计,整理和总结了已有的关于P2P在线视频系统的测量研究结果,最后对于P2P在线视频信任和污染攻击等安全问题进行了概述.%P2P technology has become one of the most effective approaches to internet video broadcast for its simple deployment, good scalability and high cost-effectiveness ratio. P2P applications such as file download and voice over IP have gained tremendous popularity, while video broadcast is still in its early stage and there are a number of key technical challenges that need to be overcome. This paper provided a comprehensive and in-depth analysis of the P2P video streaming, and discussed the characteristics of video broadcast applications and reviewed the approaches to video streaming systems architecture design. After surveying the results of measurement studied on P2P video streaming systems, then the paper overviewed security aspects of P2P live video streaming systems such as pollution attack and DoS attack.

  14. Analysis of Legal Risks to P2P Lending in China%我国 P2P 网络借贷的法律风险解析及监管应对



    通过对我国 P2P 网络借贷平台运营模式的探究,认为网络借贷平台存在民事法律风险、刑事法律风险和金融法律风险。在此基础上,借鉴美国对 P2P 网络借贷平台的监管格局,提出通过明晰监管结构、完善个人征信体系、规范中间账户管理、引入第三方担保机制或建立风险准备金制度等监管措施,增进行业自律来完善我国对网络借贷平台的监管。%Through analyzing the operational model of peer to peer lending platforms in China,this paper points out that these platforms are faced with civil risks,criminal risks,and financial risks.Based on the legal risk exploration,intro-ducing the present regulatory patterns in U.S.,the author proposes through pinpointing regulatory structure,completing personal credit system,standardizing the middle account management,introducing the third party guarantee mechanism or establishing risk reserve system,and optimizing the industry self-discipline to improve China’s supervision on P2P Lending.

  15. Learning e-Learning

    Gabriel ZAMFIR


    Full Text Available What You Understand Is What Your Cognitive Integrates. Scientific research develops, as a native environment, knowledge. This environment consists of two interdependent divisions: theory and technology. First division occurs as a recursive research, while the second one becomes an application of the research activity. Over time, theories integrate methodologies and technology extends as infrastructure. The engine of this environment is learning, as the human activity of knowledge work. The threshold term of this model is the concepts map; it is based on Bloom’ taxonomy for the cognitive domain and highlights the notion of software scaffolding which is grounded in Vygotsky’s Social Development Theory with its major theme, Zone of Proximal Development. This article is designed as a conceptual paper, which analyzes specific structures of this type of educational research: the model reflects a foundation for a theory and finally, the theory evolves as groundwork for a system. The outcomes of this kind of approach are the examples, which are, theoretically, learning outcomes, and practically exist as educational objects, so-called e-learning.

  16. P2P 网贷个人信用评价指标体系的构建%The Construction of P2P Network Lending Personal Credit Evaluation Index System

    石澄贤; 陈雪交


    In order to increase the credibility of P2P network lending platform and solve the problem of en-terprise credit risks caused by information asymmetry,personal credit evaluation index variables are se-lected in three aspects,namely,representation information,behavior information and status information combined with actual business needs.By calculating WOE and IV of variables, the significance of variables to targets in the preliminary observation is showed.The logistic regression of all variables is presented by use of SAS software.Combing IV and logistic regression,22 variables are selected as P2P network lending platform credit evaluation indexes.Through the selection,indexes which contain a large amount of information and make a lot of contribution to credit evaluation are reserved.%为增加 P2P 网贷平台信用评价的可信性,改善因信息不对称而导致的企业信用风险问题,结合实际业务需求从表征信息、行为信息及状态信息三个方面选择个人信用评价指标变量。通过计算变量的 WOE (Weight of Evidence)、IV (Information Value)值初步观测变量对目标的显著程度,再用 SAS 软件对整体变量进行逻辑回归。以 IV 和逻辑回归相结合的方式筛选指标,遴选出22个指标作为 P2P 网贷平台信用评价体系指标。这种个人信用评估指标的遴选结果保留了信息量大,对信用评价贡献概率大的指标。

  17. Ethics in E-Learning

    Bušíková, Alena; Melicheríková, Zuzana


    The use of information and communication technology has grown at an unprecedented rate and provides a revolutionary way of learning because specific information is easy to find on the Internet. One of the technology approaches in learning is e-learning or electronic learning. Whereas in the U.S., e-learning has become very popular in the recent…

  18. Can I trust you? : The importance of trust when doing business on P2P online platforms

    Andersson, David; Kobaslic, Bojan


    This report has focused on how important a buyers eWOM is compared to his/her visual information when sellers decide if they can trust this buyer. A focus company was Airbnb, an online P2P platform where private individuals can rent out their living quarters to other private persons. The method involved sending out online web surveys to approximately 200 students in Högskolan Kristianstad. Results from these surveys suggests that a buyer’s eWOM and visual information had little or no impact u...

  19. Semantic e-Learning: Next Generation of e-Learning?

    Konstantinos, Markellos; Penelope, Markellou; Giannis, Koutsonikos; Aglaia, Liopa-Tsakalidi

    Semantic e-learning aspires to be the next generation of e-learning, since the understanding of learning materials and knowledge semantics allows their advanced representation, manipulation, sharing, exchange and reuse and ultimately promote efficient online experiences for users. In this context, the paper firstly explores some fundamental Semantic Web technologies and then discusses current and potential applications of these technologies in e-learning domain, namely, Semantic portals, Semantic search, personalization, recommendation systems, social software and Web 2.0 tools. Finally, it highlights future research directions and open issues of the field.

  20. P2P and its Application in Enterprise Computing%P2P及其在企业计算中的应用

    彭舰; 杨思忠; 刘锦德


    Owing to the popularity of Napster and Guntella, the concept of P2P (Peer-to-Peer)is highlighted again.P2P is a mindset and the rethinking of the traditional network computing based on the client/server model. P2Pmeans to decentralize some aspects of a system, in order for the entities to exchange directly, which will explore theresources at the edge of network. The implication of P2P is expounded, and some typical P2P systems are listed.This paper also details the taxonomy of the architecture of P2P computing. Then, we delve into the application ofP2P in enterprise computing.

  1. Inferring playback rate and rate resets of P2P video streaming transmissions by piecewise line envelope approximation

    LI Chun-xi; CHEN Chang-jia


    Conventionally, P2P video is regarded as CBR traffic. However, our measurements have shown that the rate reset cannot be neglected in a practical IPTV system because each rate reset often leads to performance degradation. Thus, addressing the problem of inferring playback rate and rate reset in a P2P video system is significant. In this article, an algorithm termed piecewise linear envelope approximation (PLEA) is proposed, in which a follow-up time is introduced to smooth rate fluctuations in a small time scale and to adapt rate jumps in a large time scale automatically. With the PLEA algorithm, discontinuity introduced by blind segmentations adopted by current methods is avoided. Furthermore, unlike existing algorithms in which both segmentation and combinations are performed in multiple runs, only a single computation path is involved in the PLEA algorithm. This makes PLEA algorithm amenable to implementation of low complexity by either software or hardware. Both theoretical analysis and experiment based on measured data show that the PLEA outperforms existing algorithms based on segmentation.

  2. You Share, I Share: Network Effects and Economic Incentives in P2P File-Sharing System

    Salek, Mahyar; Kempe, David


    We study the interaction between network effects and external incentives on file sharing behavior in Peer-to-Peer (P2P) networks. Many current or envisioned P2P networks reward individuals for sharing files, via financial incentives or social recognition. Peers weigh this reward against the cost of sharing incurred when others download the shared file. As a result, if other nearby nodes share files as well, the cost to an individual node decreases. Such positive network sharing effects can be expected to increase the rate of peers who share files. In this paper, we formulate a natural model for the network effects of sharing behavior, which we term the "demand model." We prove that the model has desirable diminishing returns properties, meaning that the network benefit of increasing payments decreases when the payments are already high. This result holds quite generally, for submodular objective functions on the part of the network operator. In fact, we show a stronger result: the demand model leads to a "cov...

  3. 对等网络技术的新发展——JXTA%A Promising Evolution of P2P Technologies--JXTA

    黄小琴; 黎星星; 朱庆生


    With the explosion of content on the network and quantities of devices connected, it is urgently required todevelop the P2P technologies. Thus, JXTA, a new P2P technology, emerged as the times require. This paper ex-plores P2P and JXTA in particular, and then gives an applied example about it. At last, similarities and differencesbetween JXTA and other typical distributed computing technologies and their application ranges have been deeply in-vestigated.

  4. Performance evaluation of explicitsignaling for NAT traversal in peer topeer communication with emphasis onP2P-TVJawad Hussain

    Hussain, Jawad


    Peer-to-Peer (P2P) networks have become increasingly popular and have become a very successful networking paradigm. Presently P2P network boostup by P2P file sharing programs such as Napster, KaZaA, TV broadcasting etc. As network address translators (NAT) [1] and firewall devices are becoming increasingly ubiquitous and are unavoidable, and they pose a significant problem for connection establishment for peer-to-peer protocols which still in its infancy. P2P applications need to connect to e...

  5. 利用多维观测序列的KCFM混合模型检测新型P2P botnet%Application KCFM to Detect New P2P Botnet Based on Multi-Observed Sequence

    康健; 宋元章


    提出了一种新颖的综合考虑多维观测序列的实时检测模型--KCFM.通过抽取新型分散式P2Pbotnet的多个特征构成多维观测序列,使用离散Kalman滤波算法发现流量异常变化,将Multi-chart CUSUM 作为差异放大器提高检测精度.实验表明,基于多维观测序列的KCFM模型能够有效地检测新型P2P botnet.

  6. An Empirical Analysis of the Factors Influencing the P2P Lending Success%影响 P2P 网络借贷成功因素的实证分析



    利用人人贷网络借贷的交易数据,采用二元Logit回归模型,研究影响网络借贷成功的因素。研究结果表明:借款金额、借款者信用等级、历史借款失败次数与投标能否完成呈负相关关系,借款期限、借款利率、借款者性别、年龄、工资状况以及身份审核项目数对投标能否完成有正向影响。P2 P网络借贷是我国互联网金融发展的创新模式,通过对影响借贷成功因素的研究,能更好的帮助小微企业和个人成功融资,促使P2P网络借贷更加合理健康的运营。%Using transaction data collected from Renrendai Online Lending ,this article employs a binary logit regression model which researches on influencing factors on borrowing success . The results illustrate that borrowing amount ,borrower credit and history of borrowing failure time have negative effect on it ,while borrowing duration ,interest rate ,gender ,age ,wage and identity audit project number have positive impacts on it .P2P online lending is an innovation model of the development of internet finance in our country . T he research of the factors influencing the borrowing success , can better help micro‐enterprise and personal obtain financing ,w hich is also beneficial for promoting P2P online lending to be operated in a more reasonabe and healthy way .

  7. Quality in e-learning

    Masoumi, Davoud; Lindstrom, Berner


    With the growing demand for e-learning along with striving for excellence associated with globalization, there are worldwide calls for enhancing and assuring quality in e-learning, specifically in the context of the developing countries. Such calls for quality enhancement, accountability, added...... value, value for money, self-evaluation, and role players’ satisfaction in higher education settings cannot go unheeded. Addressing the concerns regarding enhancing and assuring quality in e-learning, a comprehensive e-quality framework is developed by taking into account the pros and cons...... of the previous models, frameworks, and studies of e-quality. This e-quality framework offers a structured set of factors and benchmarks as a tool for practical quality work with e-learning in virtual institutions....

  8. E-Learning Security Models

    Vladimir I. Zuev


    Full Text Available The article looks into methods and models that are useful when analyzing the risks and vulnerabilities of complex e-learning systems in an emergency management context. Definitions of vulnerability and emergency response capabilities, such as "VLE/PLE attack surface", are suggested.The article provides insight into some of the issues related to analysis of risks and vulnerabilities of e-learning systems, but more research is needed to address this difficult and comprehensive task.


    Tian Junfeng; Li Chao; He Xuemin


    In order to deal with the problems in P2P systems of file sharing such as unreliability of the service,security risk and attacks caused by malicious peers,a novel Trust Model based on Multinomial subjective logic and Risk mechanism (MR-TM) is proposed.According to the multinomial subjective logic theory,the model introduces the risk mechanism.It assesses and quantifies the peers' risk,through computing the resource value,vulnerability,threat level,and finally gets the trust value by the risk value and the reputation value.The introduction of the risk value can reflect the recent behaviors of the peers better and make the system more sensitive to malicious acts.Finally,the effectiveness and feasibility of the model is illustrated by the simulation experiment designed with Peersim.

  10. An Adaptive Multi-channel P2P Video-on-Demand System using Plug-and-Play Helpers

    Zhang, Hao; Parekh, Abhay; Ramchandran, Kannan


    We present a multi-channel P2P Video-on-Demand (VoD) system using "plug-and-play" helpers. Helpers are heterogenous "micro-servers" with limited storage, bandwidth and number of users they can serve simultaneously. Our proposed system has the following salient features: (1) it minimizes the server load; (2) it is distributed, and requires little or no maintenance overhead and which can easily adapt to system dynamics; and (3) it is adaptable to varying supply and demand patterns across multiple video channels irrespective of video popularity. Our proposed solution jointly optimizes over helper-user topology, video storage allocation and bandwidth allocation. The combinatorial nature of the problem and the system demand for distributed algorithms makes the problem uniquely challenging. By utilizing Lagrangian decomposition and Markov chain approximation based arguments, we address this challenge by designing two distributed algorithms running in tandem: a primal-dual storage and bandwidth allocation algorithm ...

  11. P2P Overlay Network Clustering Service%P2P覆盖网聚类服务

    程实; 吴产乐; 程伟; 乐俊; 贺莲



  12. Analysis and Implementation of Particle-to-Particle (P2P) Graphics Processor Unit (GPU) Kernel for Black-Box Adaptive Fast Multipole Method


    Particle-to- Particle (P2P) Graphics Processor Unit (GPU) Kernel for Black-Box Adaptive Fast Multipole Method by Richard H Haney and Dale Shires......ARL-TR-7315 ● JUNE 2015 US Army Research Laboratory Analysis and Implementation of Particle-to- Particle (P2P) Graphics Processor

  13. IPTV网络中CND与P2P结合的技术分析%The Technical Analysis for Combining CND and P2P in IPTV Network



    P2P-IPTV系统是目前IPTV应用技术发展中一个新的研究方向。针对P2P-IPTV技术发展中存在的问题进行了研究。在介绍了传统的IPTV中CDN系统架构的基础上,分析了该技术开发过程中可能遇到的难题;在讨论了P2P-IPTV技术解决上述难题优势所在的基础上,分析了IPTV网络中CDN与P2P技术结合点。%P2P-IPTV system is a new research topic in IPTV application technology development at present.In this paper,some problems which exist in P2P-IPTV technology development have been studied.Based on the introduction of the traditional CDN architecture in IPTV,this paper gives an analysis of the problems which may arise in P2P-IPTV technology development process;based on the discussion of the advantages of P2P-IPTV technology in solving the above problems,this paper gives an analysis of the technology combining points between CDN and P2P in IPTV network.

  14. P2P模型在校园网上的应用研究%Study on application of P2P network model in campus network

    王晓燕; 张伟


    针对目前流行的P2P网络模型的特点,结合非结构化的P2P网络Gnutella路由和结构化的P2P Pastry路由,提出了一种应用在校园网内的P2P结构模型方案,并给出了详细的P2P节点结构和路由,同时提出了设计该网络模型上的P2P网络应用软件的可行性.%This article in view of the present popular P2P network model characteristics,combined with unstructured P2P network Gnutella routing and structured P2P Pastry routing,puts forward a kind of application in campus network of P2P structure model,and gives the detailed P2P node structure and routing,and puts forward the design of the network model of the P2P network application software feasibility.

  15. E-learning neutron scattering

    Udby, L.; Jensen, P.; Bruun, Jonas


    E-learning offers a wide range of possibilities for evaluation and directly measuring how the students use the material and learn. This is made possible since all clicks and replies in quizzes etc. are stored in a database on which web analytics tools can be applied.......E-learning offers a wide range of possibilities for evaluation and directly measuring how the students use the material and learn. This is made possible since all clicks and replies in quizzes etc. are stored in a database on which web analytics tools can be applied....

  16. Los nuevos modelos: una solución equilibrada a la problemática del P2P

    Santiago Piñeros Durán


    Full Text Available Con la llegada de los intercambios ilegales de contenidos ocasionados por las redes P2P en internet, el derecho de autor ha demostrado debilidades sustanciales y procesales para proteger las prestaciones de los titulares de derechos en las redes digitales. Por esta razón se dio un desequilibrio en las economías de mercado de las industrias del entretenimiento a nivel mundial, quienes han optado por impulsar el reforzamiento de los esquemas de responsabilidad en contra de usuarios e IPS infractores, sin importar las implicaciones que ello supone para los consumidores de contenidos en la red y sus derechos fundamentales. Se prevé un esquema donde los nuevos modelos de negocio, licenciamiento y compensación, otorgados por las redes digitales y la cultura colectiva, demuestran que el derecho de autor puede servir como punto de balance para proteger los derechos de los titulares afectados, mientras prima la libertad de mercado en la red para difundir la cultura y la educación. Esto se concreta en un modelo de compensación alternativa que establece los parámetros en que debe funcionar el libre intercambio de contenidos con control y vigilancia estatales, a saber, el modelo Fisher.

  17. “Q-Feed”—An Effective Solution for the Free-Riding Problem in Unstructured P2P Networks

    Sabu M. Thampi


    Full Text Available This paper presents a solution for reducing the ill effects of free-riders in decentralised unstructured P2P networks. An autonomous replication scheme is proposed to improve the availability and enhance system performance. Q-learning is widely employed in different situations to improve the accuracy in decision making by each peer. Based on the performance of neighbours of a peer, every neighbour is awarded different levels of ranks. At the same time a low-performing node is allowed to improve its rank in different ways. Simulation results show that Q-learning-based free riding control mechanism effectively limits the services received by free-riders and also encourages the low-performing neighbours to improve their position. The popular files are autonomously replicated to nodes possessing required parameters. Due to this improvement of quantity of popular files, free riders are given opportunity to lift their position for active participation in the network for sharing files. Q-feed effectively manages queries from free riders and reduces network traffic significantly.

  18. HonestPeer: An enhanced EigenTrust algorithm for reputation management in P2P systems

    Heba A. Kurdi


    Full Text Available The visible success of the Peer to Peer (P2P paradigm is associated with many challenges in finding trustworthy peers as reliable communication partners. Reputation management systems are emerging in the face of these challenges. The EigenTrust reputation management system is among the most known and successful reputation systems. On the other hand, a main drawback of this system is its reliance on a set of pre-trusted peers which causes nodes to center around them. As a consequence, other peers are ranked low despite being honest, marginalizing their effect in the system. To tackle this problem, this paper proposed enhancing the EigenTrust algorithm by giving peers with high reputation values (honest peers a role in calculating the global reputation of other peers. Rather than solely depending on the static group of pre-trusted peers, the proposed algorithm, HonestPeer, selects the most reputable nodes, honest peers, dynamically based on the quality of the provided files. This makes HonestPeer more robust to the increase in the number of files and nodes in the system. Through simulation, it has been shown that HonestPeer has successfully maintained higher success rate and lower percentage of inauthentic downloads when compared to the original algorithm.

  19. Bottomonium spectroscopy and radiative transitions involving the chi_bJ(1P,2P) states at BABAR

    Lees, J P


    We use $(121\\pm1)$ million $\\Upsilon(3S)$ and $(98\\pm1)$ million $\\Upsilon(2S)$ mesons recorded by the BABAR detector at the PEP-II $e^+e^-$ collider at SLAC to perform a study of radiative transitions involving the $\\chi_{b\\mathrm{J}}(1P,2P)$ states in exclusive decays with $\\mu^+\\mu^-\\gamma\\gamma$ final states. We reconstruct twelve channels in four cascades using two complementary methods. In the first we identify both signal photon candidates in the Electromagnetic Calorimeter (EMC), employ a calorimeter timing-based technique to reduce backgrounds, and determine branching-ratio products and fine mass splittings. These results include the best observational significance yet for the $\\chi_{b0}(2P)\\rightarrow\\gamma\\Upsilon(2S)$ and $\\chi_{b0}(1P)\\rightarrow\\gamma\\Upsilon(1S)$ transitions. In the second method, we identify one photon candidate in the EMC and one which has converted into an $e^+e^-$ pair due to interaction with detector material, and we measure absolute product branching fractions. This metho...

  20. A distributed multichannel demand-adaptive P2P VoD system with optimized caching and neighbor-selection

    Zhang, Hao; Chen, Minghua; Parekh, Abhay; Ramchandran, Kannan


    We design a distributed multi-channel P2P Video-on-Demand (VoD) system using "plug-and-play" helpers. Helpers are heterogenous "micro-servers" with limited storage, bandwidth and number of users they can serve simultaneously. Our proposed system has the following salient features: (1) it jointly optimizes over helper-user connection topology, video storage distribution and transmission bandwidth allocation; (2) it minimizes server load, and is adaptable to varying supply and demand patterns across multiple video channels irrespective of video popularity; and (3) it is fully distributed and requires little or no maintenance overhead. The combinatorial nature of the problem and the system demand for distributed algorithms makes the problem uniquely challenging. By utilizing Lagrangian decomposition and Markov chain approximation based arguments, we address this challenge by designing two distributed algorithms running in tandem: a primal-dual storage and bandwidth allocation algorithm and a "soft-worst-neighbor-choking" topology-building algorithm. Our scheme provably converges to a near-optimal solution, and is easy to implement in practice. Packet-level simulation results show that the proposed scheme achieves minimum sever load under highly heterogeneous combinations of supply and demand patterns, and is robust to system dynamics of user/helper churn, user/helper asynchrony, and random delays in the network.

  1. Outliers Based Caching of Data Segment with Synchronization over Video-on Demand using P2P Computing

    M. Narayanan


    Full Text Available Nowadays live streaming plays an important role in various field of real time processing like education, research etc. The videos are maintained at the server then the clients may access the videos from the server may leads the performance problem. So the videos are downloaded by the clients and send it to the requesting clients. The mesh network is suitable for the live streaming because there is no master/slave relationship among the clients and in P2P (Peer-to-Peer live streaming, each peer holds the video segment for satisfying the needs of the requesting peer. If the cache is full the data segments are replaced by using various replacement algorithms. These algorithms are mainly used in the data segment at the head part of the cache. The tail part of the data segments are never used to satisfy the peers even though it is a relevant data segments. The proposed work mainly focuses on the data segment of the tail part for live streaming is called outliers. The tail part of the cache is synchronized with the other neighboring peers with the help of the segment table. This segment table has to maintain each peer to overcome the unavailability of the data segment at the peers. There is various tag formats are proposed for representing the tail part of the cache. In future the performance will be improved in maximum level.

  2. `Q-Feed' - An Effective Solution for the Free-riding Problem in Unstructured P2P Networks

    Thampi, Sabu M; 10.1155/2010/793591


    This paper presents a solution for reducing the ill effects of free-riders in decentralised unstructured P2P networks. An autonomous replication scheme is proposed to improve the availability and enhance system performance. Q-learning is widely employed in different situations to improve the accuracy in decision making by each peer. Based on the performance of neighbours of a peer, every neighbour is awarded different levels of ranks. At the same time a low-performing node is allowed to improve its rank in different ways. Simulation results show that Q-learning based free riding control mechanism effectively limits the services received by free-riders and also encourages the low-performing neighbours to improve their position. The popular files are autonomously replicated to nodes possessing required parameters. Due to this improvement of quantity of popular files, free riders are given opportunity to lift their position for active participation in the network for sharing files. Q-feed effectively manages que...

  3. 一种基于P2P 网络技术的复合知识云模型%A Multiplex Knowledge Cloud Model Based on P2P Network Technology

    徐小龙; 熊婧夷; 程春玲


    为了支持信息量和用户数均规模庞大的网络知识共享系统,必须采用先进的信息技术,云计算技术是理想的选择,但是仅采用云计算技术来构建知识共享系统还存在着一系列问题.文中将对等网络和云计算技术应用于大规模网络知识共享系统,提出了一种基于对等网络技术的复合知识云模型.模型本着平等、协作、分享、自由的互联网精神,并利用对等网络技术所推崇的“节点对等”思想,所有人不但共同贡献智慧和知识来协作编写百科全书,还充分调动互联网所有用户的力量,共同贡献各个用户计算机上的计算、存储资源和各种数据、软件等信息资源.基于该模型可以构建一种比现有的各种网络百科全书更为灵活、更为可靠、资源共享更为广泛的知识信息资源共享平台.文中还详细描述了基于对等网络技术的复合知识云模型MKCM(Multiplex Knowledge Cloud Model)的体系结构和工作流程,并深入探索了复合知识云模型的知识评价机制,对知识的价值进行有效的评价,从而选择最有价值的知识数据备份至服务器端以提高系统的整体性能.%In order to support network knowledge-sharing systems with the large-scale amount of information and the great number of users,advanced information technologies have to be adopted. The Cloud Computing is the ideal option. However,using the traditional Cloud Computing technology to build knowledge sharing systems can't solve all issues. In this paper, we describe how to apply Peer-to-Peer networks and Cloud Computing technologies in large-scale network knowledge-sharing systems,and present a multiplex knowledge cloud model based on P2P network technology. The model conforms to the principles of equality, cooperation, sharing and freedom of the spirit of the Internet. With the idea of "peer to peer",all users not only contribute their wisdom and knowledge to prepare encyclopedia

  4. 提高有效吞吐率的P2P TV网络编码数据传输算法%Network coding data transmission algorithm for P2P TV to improve the goodput ratio

    张志明; 周晋; 陈震; 李军


    In network coding (NO based P2P TV systems, some segments may not be able to receive the predetermined number of encoded data packets for decoding. This leads to dropping of the encoded data packets in those segments which reduces the system goodput ratio. The goodput ratio is improved by a first come first served (FCFS) transmission algorithm presented here. The algorithm partitions the buffer into two sections by skipping empty segments in the section close to the playback point (called first section). Then, it divides the requested segments into nonempty segments in the first section, nonempty segments in the second section and empty segments in the second section. The priorities are highest for the first type. The priorities of the first type are based on the greedy method, the second uses rarest-first and the third uses the random method. High priority segments are obtained from neighbors using the round-robin strategy based on the available uplink bandwidth capacity. Simulations indicate that the sum of the goodput ratio and the control overhead ratio is always close to the peer resource index (PRI) when the system uplink bandwidth capacity is inadequate. The FCFS algorithm improves the utility ratio of the users' uplink bandwidth capacity, reduces the number of dropped data packets and increases the system goodput ratio.%在基于网络编码的P2P TV系统中,有些段会因为没有收齐而不能解码,导致这些段中已收编码数据包被迫丢弃,造成系统有效吞吐率的下降.为了提高系统有效吞吐率,该文提出了一种先到先得式(FCFS)数据传输算法.该算法将待播放的缓存划分为2部分,首先主动放弃离播放点较近的那部分(第1部分)中的空段,再将其他待获取的段划分为3类,分别为第1部分中的未收齐非空段、第2部分中的未收齐非空段和第2部分中的空段.这3类段的优先级依次降低,类内各段之间的优先级分别使用贪婪式、最少者优先式和

  5. An e-Learning Theoretical Framework

    Aparicio, Manuela; Bacao, Fernando; Oliveira, Tiago


    E-learning systems have witnessed a usage and research increase in the past decade. This article presents the e-learning concepts ecosystem. It summarizes the various scopes on e-learning studies. Here we propose an e-learning theoretical framework. This theory framework is based upon three principal dimensions: users, technology, and services…

  6. An e-Learning Theoretical Framework

    Aparicio, Manuela; Bacao, Fernando; Oliveira, Tiago


    E-learning systems have witnessed a usage and research increase in the past decade. This article presents the e-learning concepts ecosystem. It summarizes the various scopes on e-learning studies. Here we propose an e-learning theoretical framework. This theory framework is based upon three principal dimensions: users, technology, and services…

  7. e-Learning Resource Brokers

    Retalis, Symeon; Papasalouros, Andreas; Avgeriou, Paris; Siassiakos, Kostas


    There is an exponentially increasing demand for provisioning of high-quality learning resources, which is not satisfied by current web technologies and systems. E-Learning Resource Brokers are a potential solution to this problem, as they represent the state-of-the-art in facilitating the exchange o

  8. E-Learning and Joomla

    Merino, S.; Martinez, J.; Gutierrez, G.; Galan, J. L.; Rodriguez, P.; Munoz, M. L.; Gonzalez, J. M.; Cordero, P.; Padilla, Y.; Mora, A.; Merida, E.; Rodriguez, F.


    For many years, university teaching was based mainly on lectures, but critics point out that lecturing is mainly a one-way method of communication that does not involve significant audience participation. Nowadays e-learning has become a distance learning paradigm using information technology as the Internet, intranets, emails and multimedia…

  9. e-Learning Resource Brokers

    Retalis, Symeon; Papasalouros, Andreas; Avgeriou, Paris; Siassiakos, Kostas


    There is an exponentially increasing demand for provisioning of high-quality learning resources, which is not satisfied by current web technologies and systems. E-Learning Resource Brokers are a potential solution to this problem, as they represent the state-of-the-art in facilitating the exchange

  10. 论P2P技术特点与网络安全%Characteristics and Network Security of P2P Technology



    This paper introduces the concept of P2P technology, technical characteristics and safety issues faced by P2P networks and to solve those problems.%本文介绍了P2P技术的概念、技术的特点以及P2P网络面临安全问题和解决这些问题的方案。

  11. Techniques de localisation et de résumé des données dans les systèmes P2P

    Hayek, Rabab


    The goal of this thesis is to contribute to the development of data localization and summarization techniques in P2P environments. At the application layer, we focus on exploiting the semantics that can be captured from the shared data. These semantics can improve the search efficiency, and allow for more query facilities. To this end, we introduce a novel data indexing technique into P2P systems that relies on linguistic summarization. Our summaries are synthetic, multidimensional views that...

  12. E-learning paradigmer og e-learning strategiudvikling

    Duus, Henrik Johannsen


    E-learning området er meget varieret hvad angår produkter, holdninger ogmeninger, og indeholder også en del 'støj' og mytedannelser, som afspejles i såvel denakademisk-videnskabelige som den journalistisk-offentlige debat om området. Dennevariation i såvel produkter som udtrykte meninger søges...... systematiseret og ordnet i fireidealtypiske paradigmer. Det vises, hvorledes disse fire paradigmer har hver sinebestemte karakteristika og udviklingsgrænser. Dette har afgørende strategisk betydningfor virksomheders og læreanstalters udvikling af e-learning, idet forkerte paradigmevalgvil hæmme udviklingen....

  13. Overlays in Mobile P2P Networks%移动对等网络覆盖网

    张国印; 李军


    The construction of overlays is a crucial problem in the research of mobile peer-to-peer networks.The architecture of overlays determines the robustness,security and performance of MP2P networks.The paper first introduces the concept of mobile P2P overlays,including the definition,significance of the construction of overlays and the classification of them.Next,three kinds of overlays,distributed unstructured,distributed structured and semi distributed (hybrid) network,are described.The application of overlays in MANET,VANET and WMN is especially introduced.Furthermore,the aforementioned overlays are analyzed and compared.Finally,the paper concludes and presents the future research directions.%在移动对等网络的研究工作中,覆盖网络的构造是一个十分关键的核心问题.覆盖网络体系结构决定了移动对等网络的健壮性、安全性和性能.首先提出移动对等覆盖网络的概念,给出了其定义、构建覆盖网的重要意义和覆盖网的分类.然后阐述了3类不同的覆盖网,即分布式非结构化网络、分布式结构化网络和半分布式(混合式)网络,其中特别论述了这些覆盖网在移动自组网、车辆自组网以及无线Mesh网络等方面的应用,并进行了分析和比较.最后,对整个移动对等覆盖网络研究工作进行了总结,并对下一步研究方向进行了展望.

  14. E-Learning Readiness in Organizations

    Jeanne Schreurs


    Full Text Available Many organizations failed in adopting e-learning. A primary reason for this failure is the lack of assessment of organizational readiness for e-learning. To reduce failure risk, organizations should assess their readiness for adopting e-learning to identify some weak points which have to be improved by taking some improvement actions. In the literature we can find a variety of e-learning readiness and measurement models. We developed a model to measure the readiness of organizations for e-learning. We have applied it on KBC bank to measure the readiness of KBC-ICT department for e-learning.

  15. E-learning Nordic 2006

    Pedersen, Sanya Gertsen


    E-learning Nordic 2006 er den første fællesnordiske undersøgelse, som specifikt fokuserer på effekten af it i uddannelsessektoren. Studiet er gennemført i Finland, Sverige, Norge og Danmark og mere end 8000 personer (elever, lærere, forældre og skoleledere i grundskoler og på de gymnasiale...... ungdomsuddannelser) har deltaget. Dette studie giver en række svar på centrale spørgsmål såsom: Hvad har vi fået ud af satsningen på it i uddannelsessektoren indtil nu? Og hvilke udfordringer inden for uddannelsessektoren står de nordiske lande foran i en globaliseret verden? E-learning Nordic 2006 er designet og...

  16. E-learning Nordic 2006

    Pedersen, Sanya Gertsen


    E-learning Nordic 2006 er den første fællesnordiske undersøgelse, som specifikt fokuserer på effekten af it i uddannelsessektoren. Studiet er gennemført i Finland, Sverige, Norge og Danmark og mere end 8000 personer (elever, lærere, forældre og skoleledere i grundskoler og på de gymnasiale...... ungdomsuddannelser) har deltaget. Dette studie giver en række svar på centrale spørgsmål såsom: Hvad har vi fået ud af satsningen på it i uddannelsessektoren indtil nu? Og hvilke udfordringer inden for uddannelsessektoren står de nordiske lande foran i en globaliseret verden? E-learning Nordic 2006 er designet og...

  17. Analysis on Optimization of P2P Network Group Algorithms%试析P2P网络群发通信算法的优化



      在当前的计算机网络运行环境中,P2P(Peer-to-Peer)是互联网整体构架的基础。这里介绍了P2P网络的运行环境和在网络运行环境中P2P技术的应用,基于当前P2P网络的应用与发展,分析了P2P网络群发通信机制的特点,提出了P2P网络群发通信算法优化的方式,以更好地达到关于P2P网络群发通信算法优化的目标,同时,需要引入“信用奖励机制”,对于贡献较大的节点可获取数据优先权,这是今后算法优化研究的重要方向。%In the current computer network environment, P2P(peer-to-peer) is the foundations of the whole Internet frame. This paper describes the operation environment of P2P network and the application of P2P technology in this environment. Based on the current application and development of P2P network, the characteristic of P2P network group communication mechanism is analyzed, and the optimization of P2P network group algorithms proposed, thus to fairly achieve the optimization target of P2P network group communication. Meanwhile, it is necessary to introduce the “reputation reward mechanism”, and thus for the node with great contribution to acquire the data priority, and this would be the important direction for algorithm optimization research.

  18. P2P overlay network model based on Cayley graph%基于Cayley图的P2P覆盖网络模型

    刘浩; 张连明; 朱同林


    One of the hotspots in structuralized P2P network research is to construct a high-powered overlay network model for P2P system.However,the clustering and symmetry properties of P2P network were not taken into account in existing P2P overlay network models.In this work,a novel P2P overlay network model is proposed by adopting Cayley graph based algebraic graph theory method.The simplicity and symmetry of the proposed model can ensure the self-organization and scalability of P2P network.Analytical and experimental results show that this model provides better robustness,higher enquiry efficiency and better load balance than existing P2P overlay network models,such as Chord and CAN.Furthermore,this model possesses the property of high clustering.%针对现有的P2P覆盖网络模型大多数没有考虑P2P网络的聚类性和对称性问题,本文采用基于Cayley图的代数图论构造方法,给出了一种新颖的P2P覆盖网络模型。该模型结构简单、高度对称,能满足P2P网络的自组织和可扩展性。分析和实验结果表明,该模型在容错性、查询效率和负载均衡方面都要优于现有的覆盖网络模型Chord、CAN,并具有高聚类性。

  19. E-learning is regaining in importance

    Schmidt, T. [LernQuotient, Huerth (Germany)


    Today - after its introduction about 10 years ago and a phase of disillusion - companies are now more investing in e-learning. Learning according to previous knowledge and the possibility to teach and circulate knowledge worldwide within a relatively short period of time are considered as advantages. Good e-learning products and qualified mentoring are decisive to make e-learning a success. In numerous case e-learning is the optimum possibility to spread knowledge quickly and sustainably. (orig.)

  20. E-Learning Divides in North Cyprus

    Uzunboylu, Huseyin; Tuncay, Nazime


    The purpose of this study is to find out the differences in e-learning competences of teachers. The independent variables used were geographic location, teaching experience, Internet access, e-learning training needs, ICT teacher/non-ICT teachers, and status. A questionnaire was developed to examine the e-learning competencies of vocational…

  1. Quality Enhancement on E-Learning

    Ossiannilsson, E. S. I.


    Purpose: Benchmarking, a method for quality assurance has not been very commonly used in higher education with regard to e-learning. Today, e-learning is an integral part of higher education, and so should also be an integral part of quality assurance systems. However, quality indicators, benchmarks and critical success factors on e-learning have…

  2. E-Learning in Mongolian Higher Education

    Tuul, Suvdmaa; Banzragch, Otgontugs; Saizmaa, Tsogzolmaa


    This paper reviews the e-learning course development in selected universities of Mongolia and attempts to classify the e-learning programs that are in practice at the tertiary education level in the country. The given paper uses both secondary and primary sources. The authors determined what factors influence e-learning type classification and how…

  3. 基于P2P应用的网络测量探讨%The Discussion about Network Measure of P2P application



    Through the P2P network and the definition of technology,and the related measurement techniques are described,we can get further awareness and understanding the importance and difficulty of measurement on P2P network application.The network measurement technology and method is proposed to solve the P2P application.%本文通过P2P网络和技术的定义,以及相关测量技术的描述,进一步认识和理解测量对P2P网络应用的重要性和困难性。并提出了较好解决P2P应用的网络测量技术和方法。

  4. The large momentum transfer reaction 12C(p,2p+n) as a new method for measuring short range NN correlations in nuclei

    Aclander, J.; Alster, J.; Barton, D.; Bunce, G.; Carroll, A.; Christensen, N.; Courant, H.; Durrant, S.; Gushue, S.; Heppelmann, S.; Kosonovsky, E.; Mardor, I.; Mardor, Y.; Marshak, M.; Makdisi, Y.; Minor, E. D.; Navon, I.; Nicholson, H.; Piasetzky, E.; Roser, T.; Russell, J.; Sargsian, M.; Sutton, C. S.; Tanaka, M.; White, C.; Wu, J.-Y.


    The reaction 12C(p,2p+n) was measured for momentum transfers of 4.8 and 6.2 (GeV/c)2 at beam momenta of 5.9 and 7.5 GeV/c. We measured the quasi-elastic reaction(p,2p) atθcm~=90 deg, in a kinematically complete measurement. The neutron momentum was measured in triple coincidence with the two emerging high momentum protons. We present the correlation between the momenta of the struck target proton and the neutron. The events are associated with the high momentum components of the nuclear wave function. We present sparse data which, combined with a quasi elastic description of the (p,2p) reaction and kinematical arguments, point to a novel way for isolating two-nucleon short range correlations.

  5. Research Status of P2P IPTV System%基于P2P的IPTV系统的研究现状



    基于P2P技术的IPTV系统借助对等节点之间的资源共享交互,不仅减轻了传统中央资源服务器的负担,还为用户提供更快速丰富的业务体验.目前P2P IPTV已然成熟且广泛应用,在这种情况下P2P IPTV也面临一些挑战,如与下一代移动标准IMS的融合、网络异构性和终端异构性所带来的问题等.基于这些挑战本文分析了几年来P2P IPTV的研究现状及方向.

  6. IPTV网络中CND与P2P结合的技术分析%The Technical Analysis for Combining CND and P2P in IPTV Network



    P2P-IPTV系统是目前IPTV应用技术发展中一个新的研究方向.针对P2P- IPTV技术发展中存在的问题进行了研究.在介绍了传统的IPTV中CDN系统架构的基础上,分析了该技术开发过程中可能遇到的难题;在讨论了P2P- IPTV技术解决上述难题优势所在的基础上,分析了IPTV网络中CDN与P2P技术结合点.

  7. What Is Good e-Learning?

    Emil Marin Popa

    Full Text Available To introduce e-learning are used informatic systems, the communication and media networks. Transfer of skills and knowledge specific e-learning is possible, mainly using computer and networks. E-learning using electronic applications and processing in order to learn. Learning and e-learning applications are based on Web technology, which is computer based, virtual classroom and digitalcollaboration. Content is delivered via the Internet site, audio tape or video, satellite TV and CD-ROM. E-learning applications are led by an instructor and typically include text, images, animation, video and audio.

  8. Survey on P2P and P4P technologies%P2P和P4P技术的研究

    张永芳; 于王樂


    This paper totally summaried the the concept of P2P and P4P technologies.Firstly,it analysed their advantages and disadvantages . Secondly mainly introduced the current research status about copyright issues,broadband network crisis,security issues of P2P technologies and comparison ofP2P and P4P technologies.And then cited the Working principle ofP2P.Finally.summarized and pointed out some content of future research.%全面阐述了 P2P和P4P技术的概念,分析了各自网络的特点,重点介绍了 P2P系统中版权问題、网络宽带危机和安全问題等关键技术研究现状以及P2P和P4P技术二者的对比。通过两个实例介绍了 P4P的工作原理,最后指出了需要进一步研究的内容。

  9. 基于P2P网络的智能电网模型%The Smart Grid Modle Based on the P2P Network

    韩祺祎; 张林山; 文红


    智能电网是一个动态、分布式的系统。作为一个分布式的网络系统,P2P网络允许弹性的处理节点的接入与退出,也能均衡智能网络中这些节点不稳定的功率输出。本文在讨论P2P网络与分布式智能电网模型各自特点的基础上,给出了P2P网络与分布式智能电网模型结构的一一对应关系模型。%Due to the dynamic and distributed nature, smart gird is suitable for P2P applications. As a distributed network system, P2P allow nodes resiliently access and exit, as well as balance the unstable power output of power facilities in smart grid. This paper proposes a distributed smart grid model based on P2P network and analyzes the P2P file-sharing system for smart grid model.

  10. 基于蓝牙Piconet的LEGO多机器人P2P通信%Bluetooth Piconet based P2P communication among LEGO multi-robots

    石博天; 张学良


    P2P通信是构建复杂多机器人系统的基础,由于LEGO NXT资源有限,不适于采用常用的Scatternet机制实现P2P通信.以支持蓝牙设备的PC作为中控机和网络主设备,基于Piconet,在中控机上提供可以接收/缓存/转发来自各NXT的通信数据,通过封装,在逻辑上形成P2P通信网络.协同舞蹈4机器人系统原型的研制工作验证了该组网通信机制可行.%P2P conmmunication is the basis of constructing multi-robot system. Due to limited resources, the bluetooth Scattemet is not suitable for the realization of P2P. In this paper, a PC with bluetooth was used as the master device and central controllor, a logical P2P network based on bluetooth Piconet was realized with receiving/buffering/forwarding messages from all NXTs by the communication server on the PC. The feasibility of the network was verified by the research work of a type of 4-cooperative dancing robot.

  11. 非结构化P2P系统Overlay优化技术综述%Survey of Overlay Optimization Techniques in Unstructured P2P Systems

    黄宇; 金蓓弘


    非结构化P2P Overlay网络的结构松散, 网络中资源的分布没有明确的限制, 这使得非结构化P2P Overlay网络中的资源搜索在很大程度上依赖于通信开销巨大的泛洪法, 因而非结构化P2P系统在伸缩性, 可用性等方面, 存在明显的不足. 非结构化P2POverlay网络的上述特点决定了非结构化P2P Overlay优化技术的重要性. 本文分四大类别, 对非结构化P2P Overlay优化技术进行了介绍, 分析比较了各类方法的优劣以及它们的适用场合, 并在此基础上对未来工作进行了展望.

  12. P2P网络模型的形式化描述方法%A formal description method for P2 P network models

    沈军; 黄元; 宋金晶


    为了更好地适应对Intemet中迅速发展的新形态P2P网络应用进行建模的需求,深入研究了适于描述多方并发网络交互的形式化建模方法.首先,对P2P网络系统模型的各项特征及其分类进行了探讨.然后,参照构件化建模的研究思路,基于对P2P应用建模需求的分析,提出了一种运用通信顺序进程(CSP)进行描述的P2P网络应用的形式化描述方法.借助CSP进程组表示,该方法能够更为方便精确地描述P2P系统中以多方交互为主的动态交互关系,探讨了CSP非确定性语义在P2P交互建模中的应用.最后通过一个新型P2P媒体点播系统的实例展示了以上描述方法的应用,验证了该方法在描述并行交互关系等方面的能力.%To meet the requirements of modeling the new modality of peer-to-peer(P2P) network applications which have been rapidly developing in the Internet recently,a formal descripfion method for modeling multiparty concurrent network interactions is Studied.The main characteristics and the classifications of P2P systems are discussed.Considering the requirements of P2P application modeling and referring to the component-based modeling thought,a description method based on communicating sequenfiM processes(CSP)is proposed for the P2P network models.By using a CSP process group,this method can describe the dynamic interactive relationship Which focuses on multiparty concurrent interaction of P2P systems more advantageously and accurately.The application of nondeteministic semantemes of CSP in describing the interactive relationshiP of P2P networks is discussed.The advantages and description abilities of the proposed method are demonstrated through the modeling of a new P2P media-on-demand system.

  13. E-learning implementation from strategic perspective

    Lin, Chih-Cheng; Ma, Zheng; Chang, Chi-Cheng


    E-learning is spreading not only in the USA but also in the UK. Most available literature concentrates on e-learning platforms, but do not explore the factors related to e-learning implementation from a strategic or organisational perspective. Many academic institutes and their IT departments...... are now facing the challenges of selecting and implementing the right e-learning solutions. In order to understand the entire process associated with e-learning implementation in higher institutes which has not yet been a linear process but came probably with top-down, bottom-up, or flowers blooming...... study of one higher institute's experience, the paper shows that maintaining the alignment is still a crucial issue but hard to achieve. The pressure of achieving alignment may be even more considerable with the implementation of e-learning systems....

  14. E-learning support for lifelong learning

    Doležalová, Klára


    The bachelor thesis E-learning support of lifelong learning concerns the topic of e-learning. Its main goal is to create and implement an e-learning course of Czech language for foreigners, more specifically for foreign scientists who come to the Czech Republic for work. This goal is reached in the practical part of the thesis which describes the process of creating the course with learning management system Moodle and its following implementation into practice. The theoretical part focu...

  15. Interoperability in pedagogical e-learning services

    Queirós, Ricardo


    The ultimate goal of this research plan is to improve the learning experience of students through the combination of pedagogical eLearning services. Service oriented architectures are already being used in eLearning but in this work the focus is on services of pedagogical value, rather then on generic services adapted from other business systems. This approach to the architecture of eLearning platforms raises challenges addressed by this work, namely: conceptual modeling of the pedagogica...

  16. Can E-learning change work practices?

    Noesgaard, Signe Schack


    behavior change to occur. On the other hand, e-learning can be as important as face-to-face instruction in preparing the ground for advancing work practices, when e-learning is designed in acknowledgement of its strength and limitations. In outlining the above arguments, this article contributes a four......, the article acknowledges organizational cost concerns regarding individualized scaffolding and discusses how a redefinition of e-learning can cost-effectively scaffold employees to sustainable change....

  17. Pedagogical quality in e-learning

    Dalsgaard, Christian


    The article is concerned with design and use of e-learning technology to develop education qualitatively. The purpose is to develop a framework for a pedagogical evaluation of e-learning technology. The approach is that evaluation and design must be grounded in a learning theoretical approach....... Finally, on the basis of the frameworks, the article discusses e-learning technology and, more specifically, design of virtual learning environments and learning objects. It is argued that e-learning technology is not pedagogically neutral, and that it is therefore necessary to focus on design...

  18. Assessing students' readiness towards e-learning

    Rahim, Nasrudin Md; Yusoff, Siti Hawa Mohd; Latif, Shahida Abd


    The usage of e-Learning methodology has become a new attraction for potential students as shown by some higher learning institutions in Malaysia. As such, Universiti Selangor (Unisel) should be ready to embark on e-Learning teaching and learning in the near future. The purpose of the study is to gauge the readiness of Unisel's students in e-Learning environment. A sample of 110 students was chosen to participate in this study which was conducted in January 2013. This sample consisted of students from various levels of study that are foundation, diploma and degree program. Using a structured questionnaire, respondents were assessed on their basic Internet skills, access to technology required for e-Learning and their attitude towards characteristics of successful e-Learning student based on study habits, abilities, motivation and time management behaviour. The result showed that respondents did have access to technology that are required for e-Learning environment, and respondents were knowledgeable regarding the basic Internet skills. The finding also showed that respondents' attitude did meet all characteristics of successful e-Learning student. Further analysis showed that there is no significant relationshipeither among gender, level of study or faculty with those characteristics. As a conclusion, the study shows that current Unisel's students are ready to participate in e-Learning environment if the institution decided to embark on e-Learning methodology.

  19. E-Learning: Future of Education



    This paper highlights the significance of E-learning in modern education and discusses its technical aspect, market, pros and cons, comparison with instructor led training and possibility of weather E-learning will replace the old classroom teaching. Presently the concept of E-learning is becoming very popular as the numbers of internet savvy users are increasing. E-learning gives the advantage of 24x7 and 365 days a year round access as compared to Instructor-Led Training, which is one time ...

  20. Notice of Retraction: Enhanced Link based Congestion Control (ELCC in Peer-to-Peer (P2P based Video on Demand (VoD System

    Arockia Xavier Annie. Rayan


    Full Text Available The following article has been retracted by the Editorial Board and the Publisher of Journal of Networks: “Enhanced Link based Congestion Control (ELCC in Peer-to-Peer (P2P based Video on Demand (VoD System” by Arockia Xavier Annie Rayan and Yogesh Palanichamy Journal of Networks Volume 7, Number 10, October 2012, Pages: 1515-1522 doi:10.4304/jnw.7.10.1515-1522 The retraction is based on the determination of redundant publication. The same article has been published as follows: “Enhanced Link based Congestion Control (ELCC in Peer-to-Peer (P2P based Video on Demand (VoD System” by Arockia Xavier Annie R., Vanitha Sheba M. and Yogesh P. International Journal of Computer Applications 36(1:18-26, December 2011. Published by Foundation of Computer Science, New York, USA URL:

  1. New P2P Botnet with High Robustness%一种高鲁棒性的新型P2P僵尸网络

    谢静; 谭良


    This paper presents a honeypot-prescient semi-distrbuted P2P Botnet. The robustness of such a Botnet is discussed based on two metrie functions C(p), D(p), and the robustness changee when the pecr-list updating procedure runs oncc with different number of scrvent bots. Results show that the new P2P Botnet has higher robustness than traditional Botnet.%提出一种利用认证sensor组建的蜜罐先知型半分布式P2P僵尸网络(Botnet),通过连接比C(p)和度数比D(p)2个度量函数,并在peer-list更新过程中使用不同数鼍servent bots,讨论其鲁棒性的变化.结果表明,与传统Botnet相比,该类Botnet具有较高的鲁棒性.

  2. P2P网络中Free-rider的平衡机制%Balance Mechanism on Free-rider in P2P Network

    李玉玲; 刘玉华; 许凯华; 潘华强


    针对P2P 网络中出现的free-rider 现象,提出一种控制点位于服务提供节点上的平衡机制.该机制充分考虑P2P 网络拓扑结构不一致的问题,并允许一定数量的free-rider 节点存在.实验证明,该机制既能有效利用网络资源,提高交易的成功率,又能对严重的free-rider行为进行抑制.

  3. Recognition of P2P Bots Control Behavior%P2P僵尸控制行为识别技术研究

    陈昊; 李之棠; 王斌斌; 李冬


    Compared to traditional centralized-based bots, P2P-based bots are more concealable and robust due to the distributed control mechanism. In this paper, we make a deep analysis and study on control behavior of P2P bots. First, we describe the concept of control flow similarity and quantitate it appropriately, secondly, we implement Pearson hypothesis testing algorithm to identify P2P bots control flows, and finally, we use automatic classification technique to make a second determination. Experiments show that the proposed method can effectively recognize P2P bots control behavior in campus with relatively low false positive.%传统僵尸程序依赖于集中控制,P2P僵尸的传播和控制方式都是分布式的,使其更具隐蔽性和健壮性.本文通过分析P2P僵尸的特征,对其控制行为进行了较为深入的研究.首先,阐述了控制流相似性的概念并对其做出合理量化;其次,利用皮尔逊序列假设检验法来识别P2P僵尸控制行为;最后,通过自动分类技术来进行二次判定,以完成自动检测.实验和数据分析表明该方法能够有效的识别校园网内P2P僵尸的控制行为,与相关的方法相比,误报显著降低.

  4. P2P网络安全及防御技术研究综述%Survey of P2P Network Security and Defense Mechanism

    刘悦; 李强; 李舟军


    The applications based on P2P networks have been playing an important role in the Internet. P2P networks with the distributed architecture are scalable and flexible while they are facing the enormous security challenges. This paper began with an overview of the concepts and features of the P2P network,and explained the difference between it and traditional C/S structure, then detailed the three popular methods of attack against the P2P networks:Sybil attack, Eclipse attacks and DDoS attack,and pointed out the relations and differences of the three kinds of attack, finally gave an overview of research on the defensive measures against the attacks.%基于P2P网络的各类应用逐渐占据了互联网应用中的重要地位,其采用的分布式结构在提供可扩展性和灵活性的同时,也面临着巨大的安全风险和挑战.首先概述了P2P网络的基本概念与特点,并说明了P2P系统与传统C/S结构系统的区别;随后详细介绍了目前对P2P网络威胁和影响最大的3种攻击方法:Sybil攻击、Eclipse攻击和DDoS攻击,指出了3种攻击方法的联系与区别;最后分别概述了针对这3种攻击方法相应的防御措施.

  5. The use of δ13C isotope ratio mass spectrometry for methamphetamine profiling: comparison of ephedrine and pseudoephedrine-based samples to P2P-based samples.

    Toske, Steven G; Morello, David R; Berger, Jennifer M; Vazquez, Etienne R


    Differentiating methamphetamine samples produced from ephedrine and pseudoephedrine from phenyl-2-propanone precursors is critical for assigning synthetic route information for methamphetamine profiling. The use of isotope ratio mass spectrometry data is now a key component for tracking precursor information. Recent carbon (δ(13)C) isotope results from the analysis of numerous methamphetamine samples show clear differentiation for ephedrine and pseudoephedrine-produced samples compared to P2P-produced samples. The carbon isotope differences were confirmed from synthetic route precursor studies.

  6. Scalable P2P Overlay Architecture for MMOG%一种支持MMOG的可伸缩P2P覆盖网络架构

    杜玲; 石祥滨; 李宇航


    针对网络游戏独特的伸缩性和局部性需求,提出一种支持MMOG的可伸缩P2P覆盖网络架构SPOAR( scalable P2P overlay architecture).SPOAR在结构化P2P覆盖网络方案分级设计的基础上采用基于MANET的非结构化P2P节点拓扑组织方案来维护节点在游戏世界的邻居拓扑及进行邻点发现.实验表明SPOAR覆盖网络架构在保持全局连通性的同时提高了系统的伸缩性,SPOAR的拓扑一致性算法和容错实现机制能够较好的适应MMOG的动态性.%In view of the particular local requirement and scalable requirement of MMOG, this paper propose a scalable P2P overlay architecture (SPOAR) for MMOG. On the basis of structured P2P overlay architecture, this paper adopts the unstructured P2P scheme based on MANET to maintenance neighbor topology in the game world and perform neighbor discovery. The simulation results show that SPOAR overlay architecture achieves a balance between global connectivity and local communication timeliness and has good scalability. The topological consistency algorithm and the fault-tolerant realization mechanism of SPOAR can better adapt to the dynamic MMOG.

  7. P2P网络技术在煤炭运输中的应用%Application of P2P Network Technology in Coal Transprtation

    王文凡; 王丽娟


    作为一种网络应用模式,P2P网络技术在煤炭运输应用过程中,有效解决了传统网络模式中存在的种种弊端,弱化甚至取消了服务器的作用,突破了传统煤炭运输过程中存在的瓶颈,大大提高了煤炭运输效率。文章从我国煤炭运输现状分析着手,通过研究煤炭运输中P2P网络技术的网络结构及原理,重点探索P2P网络技术在煤炭运输中是如何应用的。%As a kind of network application mode, P2P network technology application in coal transportation process, effectively solve the traditional network mode there are various drawbacks, weakening or even cancelled server role, broke through the traditional coal transportation occurred in the process of bottleneck, greatly improving the efficiency of coal transportation. This paper will be from the analysis of the status of coal transportation to, through the study of coal transportation P2P network technology, network structure and principle focus for P2P network technology in coal transport is the application.

  8. Research on NAT Traversal Mechanism for P2P Networks%面向P2P网络应用的NAT穿透机制研究

    于坤; 陈晓兵


    This paper discusses the problems in the communication among the P2P nodes when the NAT is used in the network. NAT traversal mechanism is researched systematically to work out an integrate network architecture. Through the new adaptation layer added between the transport and the application one, all kind of P2P systems can access the underlying network with a united interface. Moreover, some new designs are introduced to improve the robustness and stability of P2P networks with NATs.%针对NAT环境下P2P网络通信存在的问题,系统化的进行NAT穿透机制的研究,提出一种完整的NAT穿透的网络体系结构。通过在运输层与应用层之间增加新的适配层,实现多种P2P应用系统对底层网络的统一访问接口,并设计了多种新的机制来增强NAT环境下P2P网络的鲁棒性与稳定性。

  9. P2P Network Resources Retrieval System Based on XML%基于XML的P2P网络资源检索系统



      结合P2P技术和XML技术在挖掘网络上广泛分布的异构资源的优势,构建了一个基于XML的高效的P2P 分布式网络资源检索系统,采用强大的全文检索开源工具包 Lucene 进行了实现,并对核心功能在基于android 平台的移动客户端进行了延伸。本系统的设计和解决方案对于解决网络上异构资源的共享具有重要的借鉴意义。%By combining the advantages of P2P network technology and XML technology in mining the heterogeneous data distributed on the web, this paper built an efficient P2P network resources retrieval System. And it was implemented with the open source toolkit Lucene. The core function of this system is stretched on android platform of the mobile client. The design and solution of this system has its significant reference to solve the information sharing of hetero-geneous resources on the web.

  10. 一种P2P网络环境下的OLAP查询方案%OLAP query method in P2P network. Computer Engineering and Applications

    周攀; 杨科华; 周利民


    传统网络环境和P2P环境中,客户端向OLAP服务器提交OLAP查询,并从服务器获取查询结果,OLAP服务器的负载将随着客户端的增加而急剧增加.设计了一种基于P2P(Peer-to-Peer,点对点技术)技术的DQDC(Distributed Query Data Cube,多维数据集的分布式查询)算法,实现P2P网络中语义级的多节点Data Cube数据共享,从而提高系统整体的决策分析性能.%The clients submit queries to the OLAP server and get the corresponding results from the server in the traditional network and the P2P network. However,the load of OLAP server sharply increases with the increase of clients.A distributed query data cube algorithm based on peer-to-peer technology is proposed. It achieves multi-node data cube data sharing in P2P semantic-level,thereby can improve the performance of system decision analysis.

  11. P2P电子商务信任模型研究%Research on trust model of P2P electronic commerce

    孟宪福; 张磊; 王旭


    为解决P2P电子商务中恶意节点的欺诈问题,提出一种电子商务信任模型.模型采用带超级节点的混合P2P网络拓扑结构,将P2P网络划分为不同的域,对域内和域间节点分别进行信任度的计算.模型考虑到交易金额和时间等因素,提高了对信任度计算的准确性.实验结果表明,模型可有效减少恶意交易行为的发生.%In order to solve the problem of the cheat of malicious users in P2P electronic commerce, this paper presented a trust model of electronic commerce. The model used the structure of mixed P2P network with super nodes, made P2P network to some different domains and computed the trust degree respectively for the nodes in and between domains. The model consi-dered the amount and time of the trade and enhanced the veracity of the computing of the trust degree. Experimental results manifest that the model can decrease the malicious trade effectively.

  12. Time-resolved UV-IR pump-stimulated emission pump spectroscopy to probe collisional relaxation of $8p\\,^2P_{3/2}$ Cs I

    Salahuddin, Mohammed; McFarland, Jacob; Bayram, S Burcin


    We describe and use a time-resolved pump-stimulated emission pump spectroscopic technique to measure collisional relaxation in a high-lying energy level of atomic cesium. Aligned $8p\\,^2P_{3/2}$ cesium atoms were produced by a pump laser. A second laser, the stimulated emission pump, promoted the population exclusively to the $5d\\,^2D_{5/2}$ level. The intensity of the $5d\\,^2D_{5/2}\\rightarrow6s\\,^2S_{1/2}$ cascade fluorescence at 852.12 nm was monitored. The linear polarization dependence of the $6s\\,^2S_{1/2}\\rightarrow8p\\,^2P_{3/2}\\rightarrow5d\\,^2S_{5/2}$ transition was measured in the presence of argon gas at various pressures. From the measurement, we obtained the disalignment cross section value for the $8p\\,^2P_{3/2}$ level due to collisions with ground-level argon atoms.

  13. Experiences with E-learning in Ophthalmology

    Seema Dutt Bandhu


    Full Text Available Introduction: E-learning is the use of internet for the purpose of education. E-learning in medical education is at a nascent stage in our country. The present study was carried out with the purpose of introducing e-learning to third year medical students in the subject of Ophthalmology and taking feedback on their attitude towards the new methodology of teaching and evaluating. Materials and Methods: E-learning was introduced to the seventh semester students of MBBS in the subject of Ophthalmology. The topics were converted to web friendly format and used for teaching and evaluating. Feedback was taken from the students on completion of the term on their attitudes towards e-learning and their views on the scope of e-learning in medical education. Results: All the students agreed on the usefulness of e-learning in medical education. Eleven students (27.5% found the medium of e-learning to be interesting, 15 (37.5% considered it to be easy and accessible, 10 (25% found it to be fast and easy, 4 (10% considered it to be a medium which can give updated information. Twenty-three (57.5% students considered that e-learning should be a medium of instruction in all the subjects, 15 (37.5% students considered its usefulness in clinical subjects only. Twenty-eight students (70% desired that e-learning should be used to provide important notes, questions, MCQs on all topics. Conclusions: E-learning is well accepted as a medium of instruction by medical students.

  14. ENERCA: e-learning platform

    Patricia Aguilar-Martínez


    Full Text Available ENERCA (the European Network for Rare and Congenital Anemias is a European Commission funded project since 2002. Rare anaemias in Europe comprise haemoglobin disorders, such as thalassemias or sickle cell disease, and other rarer disorders, including inherited diseases of the red cell membrane, of the red cell enzymes, as well as anaemias related to disorders of iron metabolism. Education and training on rare anaemias is one of the main objectives of ENERCA and several educational initiatives have been undertaken during the past and present phases of the project. Among these, the organisation of courses for health professionals, the provision of videos with prevention messages for patients and general practitioners were part of the previous phase, ENERCA 3. In the current phase of the ENERCA project, called e-ENERCA, the workpackage dedicated to Education and Training mainly focuses on training of young physicians, biologists or scientists in the field of diagnosis and management of rare anaemias. The specificity of e-ENERCA is to be based principally on new communication e-tool. Two main educational axes will be developed: the organisation of on-site courses including interactive sessions with voting boxes and the implementation of an online e-learning platform.

  15. Key Technologies in P2P Media Streaming%P2P网络流媒体关键技术

    秦丰林; 刘琚


    Over the past decade, Peer-to-Peer (P2P) media streaming technology, as a promising solution for large-scale media streaming,has always been of a great research interest for both the academia and industrial communities,and a great variety of P2P streaming systems have been developed and widely deployed on the Internet. In this paper, we present a comprehensive and indepth survey of existing typical P2P streaming systems,in which the core technologies,including overlay network construction and data scheduling mechanism, are detailed introduced and analyzed. We also briefly discuss the enhancement technologies such as video coding, network coding, overlay network topology optimization, and security and incentive mechanisms. Performances of several typical P2P streaming systems are also compared. Finally, we point out the open issues and challenges in P2P streaming research and comment on possible future research directions.%P2P网络流媒体技术一直是学术界和产业界的研究热点.本文围绕覆盖网络拓扑结构,对现有的P2P流媒体系统作了全面的归类总结,深入介绍和分析了覆盖网络构建、数据块调度策略等P2P流媒体核心技术,并概要讨论视频编码、网络编码、覆盖网络拓扑优化、安全与激励机制等P2P流媒体相关增强技术.对典型P2P流媒体系统的性能进行了比较,指出了P2P流媒体技术研究面临的问题和挑战,并对将来的研究方向作了展望.

  16. Pedagogical quality in e-learning

    Dalsgaard, Christian


    The article is concerned with design and use of e-learning technology to develop education qualitatively. The purpose is to develop a framework for a pedagogical evaluation of e-learning technology. The approach is that evaluation and design must be grounded in a learning theoretical approach, an...

  17. E-Learning im Museum und Archiv

    Gruber, Marion


    Gruber, M. R. (2009). E-Learning im Museum und Archiv. Vermittlung von Kunst und Kultur im Informationszeitalter. Saarbrücken: VDM Verlag Dr. Müller. Available on

  18. New e-learning method using databases

    Andreea IONESCU


    Full Text Available The objective of this paper is to present a new e-learning method that use databases. The solution could pe implemented for any typeof e-learning system in any domain. The article will purpose a solution to improve the learning process for virtual classes.

  19. International E-Learning Business: Opportunities & Strategies.

    Hasebrook, Joachim P.; Rudolph, Dirk W.

    Education is already a big business. E-learning, by making it easy to import information and skills to anyone, anywhere, anytime, and for any purpose will grow the education market. The big winners will be those vendors that identify and serve emerging and sometimes hidden markets. The biggest growth segments unleashed by e-learning are education…

  20. A Distributed Intelligent E-Learning System

    Kristensen, Terje


    An E-learning system based on a multi-agent (MAS) architecture combined with the Dynamic Content Manager (DCM) model of E-learning, is presented. We discuss the benefits of using such a multi-agent architecture. Finally, the MAS architecture is compared with a pure service-oriented architecture (SOA). This MAS architecture may also be used within…

  1. Can E-Learning Change Work Practices?

    Noesgaard, Signe Schack


    Stand-alone e-learning is unlikely to change work practices. This claim contrasts with a comprehensive body of research arguing that e-learning is at least as effective as face-to-face instruction in improving work performance. Such a comparison is, however, problematic. On the one hand, it relies on the premise that face-to-face instruction is…

  2. Virtual Reality for Collaborative E-Learning

    Monahan, Teresa; McArdle, Gavin; Bertolotto, Michela


    In the past, the term e-learning referred to any method of learning that used electronic delivery methods. With the advent of the Internet however, e-learning has evolved and the term is now most commonly used to refer to online courses. A multitude of systems are now available to manage and deliver learning content online. While these have proved…

  3. Teaching Aspects of E-Learning

    Seok, Soonhwa


    E-Learning is a new form of pedagogy for learning in the 21st century. E-Teachers are e-Learning instructional designers, facilitators of interaction, and subject matter experts. The roles of e-Teachers are to enhance learners' cognitive engagement and interaction. This is achieved by using the benefits of computer mediated communication--greater…

  4. E-Learning, Time and Unconscious Thinking

    Mathew, David


    This article views the temporal dimensions of e-learning through a psychoanalytic lens, and asks the reader to consider links between online learning and psychoanalysis. It argues that time and its associated philosophical puzzles impinge on both psychoanalytic theory and on e-learning at two specific points. The first is in the distinction…

  5. Integrated Model for E-Learning Acceptance

    Ramadiani; Rodziah, A.; Hasan, S. M.; Rusli, A.; Noraini, C.


    E-learning is not going to work if the system is not used in accordance with user needs. User Interface is very important to encourage using the application. Many theories had discuss about user interface usability evaluation and technology acceptance separately, actually why we do not make it correlation between interface usability evaluation and user acceptance to enhance e-learning process. Therefore, the evaluation model for e-learning interface acceptance is considered important to investigate. The aim of this study is to propose the integrated e-learning user interface acceptance evaluation model. This model was combined some theories of e-learning interface measurement such as, user learning style, usability evaluation, and the user benefit. We formulated in constructive questionnaires which were shared at 125 English Language School (ELS) students. This research statistics used Structural Equation Model using LISREL v8.80 and MANOVA analysis.

  6. E-learning and educational diversity.

    Forman, Dawn; Nyatanga, Lovemore; Rich, Terry


    This article discusses the nature of electronic learning (E-learning) and argues for its centrality to educational diversity and the shift from teaching to learning. It is argued that E-learning is the new wave strategy that sits comfortably with other strategies developed for the 21st century. As such it challenges the traditional 'banking concept' of education, where the teacher is seen as the font of knowledge as long as students acknowledge this and are eager to absorb the teacher's vital knowledge. The article argues that E-learning should replace what Freire (1994) calls the backing concept of education, which is at odds with other 21st century approaches such as lifelong learning, open and flexible learning and the accreditation of prior learning (APL) to name only a few. In suggesting the shift from the traditional approach to E-learning, the article acknowledges issues of quality assurance and the need to maintain not only standards of achievements but also the comparability of those standards. Strategies for developing E-learning material and maintaining standards are discussed. McKey (2000) and Salmon's (2001) model of E-learning development and management are used to show how E-learning works in practise. The article then focuses on the role of E-learning as a catalyst for educational diversity, freedom to learn and equality of opportunity. While E-learning encourages diversity it paradoxically creates programmes that are more specifically tailored to the market needs than traditionally validated programmes. This is seen as very good in terms of addressing specific needs, for instance, specific knowledge and skills for a particular market. The learners or students in that particular market will feel that their specific needs are recognized and addressed, and will thus see the E-learning programme as having relevance for them. The article concludes by asserting that adequate resources, particularly learner support, will distinguish quality or good

  7. E-Learning in postsecondary education.

    Bell, Bradford S; Federman, Jessica E


    Over the past decade postsecondary education has been moving increasingly from the classroom to online. During the fall 2010 term 31 percent of U.S. college students took at least one online course. The primary reasons for the growth of e-learning in the nation's colleges and universities include the desire of those institutions to generate new revenue streams, improve access, and offer students greater scheduling flexibility. Yet the growth of e-learning has been accompanied by a continuing debate about its effectiveness and by the recognition that a number of barriers impede its widespread adoption in higher education. Through an extensive research review, Bradford Bell and Jessica Federman examine three key issues in the growing use of e-learning in postsecondary education. The first is whether e-learning is as effective as other delivery methods. The debate about the effectiveness of e-learning, the authors say, has been framed in terms of how it compares with other means of delivering instruction, most often traditional instructor-led classroom instruction. Bell and Federman review a number of meta-analyses and other studies that, taken together, show that e-learning produces outcomes equivalent to other delivery media when instructional conditions are held constant. The second issue is what particular features of e-learning influence its effectiveness. Here the authors move beyond the "does it work" question to examine how different instructional features and supports, such as immersion and interactivity, influence the effectiveness of e-learning programs. They review research that shows how these features can be configured to create e-learning programs that help different types of learners acquire different types of knowledge. In addressing the third issue--the barriers to the adoption of e-learning in postsecondary education--Bell and Federman discuss how concerns about fraud and cheating, uncertainties about the cost of e-learning, and the unique

  8. Elastic Overlay Construction Method for P2P VoD Based on Cloud Service Delivery Network%基于云服务传递网络的弹性P2P VoD覆盖网构造方法

    史佩昌; 王怀民; 刘雪宁; 袁小群; 尹刚; 史殿习


    The P2P VoD which is deployed on the infrastructure of Cloud Service Delivery Network (CSDN), all users of the same program in each CSDN node forms a P2P overlay network. However, the concurrent users of a large number of programs are scarce within each, CSDN node. So it's a great challenge to solve the peer resource scarce problem in the construction of P2P VoD overlay on the condition of traffic localization. For the challenge, this paper presents an Elastic Construction Method (ECM) for P2P overlay. In order to solve the peer resource scarce problem, ECM elastic scales the construction scope of P2P overlay on the bases of the resource index. Meanwhile, ECM chose the scale path based on the distances among CSDN nodes to realize P2P traffic localized. Finally, through the simulation, we validate the effectiveness of ECM in balancing CSDN server load and cross-ISP traffic.%部署于云服务传递网络(Cloud Service Delivery Network,CSDN)基础设施的P2P VoD系统,在每个CSDN节点内将同一节目的所有用户构建成P2P覆盖网,但CSDN单节点内大量节目的并发用户稀少.因此,如何在兼顾流量本地化的前提下,解决CSDN架构下P2P VoD覆盖网构造中Peer资源稀疏问题是当前面临的一个挑战.为此,提出一种P2P覆盖网的弹性构造方法ECM( Elastic Construction Method).ECM依据资源索引来弹性扩展P2P覆盖网的构造范围,有效解决Peer资源稀疏问题;同时根据CSDN节点间距离来选择扩展路径,实现P2P流量本地化.最后模拟实验结果表明,ECM能有效均衡服务器负载和跨ISP流量.

  9. Psychological myths in e-learning.

    Clark, Donald


    Traditional education and training has paid scant attention to the psychology of learning. Despite detailed research into motivation, distribution and reinforcement, most current methods of delivery still rely on a supply-led, lecture and classroom-based model that flies in the face of the theory. With e-learning we have a chance to reflect on this gap between theory and practice. E-learning, in the sense of web-based learning, is a new discipline but the psychology of learning has a much longer pedigree. This paper relates some common myths about e-learning back to some major themes in the psychology of learning. Is e-learning faster and more effective? Many people get the wrong learning at the wrong time. Can e-learning help with prerequisite knowledge? Should the learning be massed or distributed, i.e. all at once or little and often? There are also the issues of motivation and cognitive engagement. How can e-learning motivate learners or how can we motivate learners into using this new medium? What type of cognitive engagement is necessary for learning? Traditional 'sheep-dip' methods of learning are poor on reinforcement. Can e-learning help reinforce learning?

  10. E-Learning: Future of Education



    Full Text Available This paper highlights the significance of E-learning in modern education and discusses its technical aspect, market, pros and cons, comparison with instructor led training and possibility of weather E-learning will replace the old classroom teaching. Presently the concept of E-learning is becoming very popular as the numbers of internet savvy users are increasing. E-learning gives the advantage of 24x7 and 365 days a year round access as compared to Instructor-Led Training, which is one time class that must be scheduled. E-learning is cost effective as course content once developed could be easily used and modified for teaching and training. E-learning also provides students freedom from carrying heavy school bags and stop cutting of trees for the sake of paper, pencil and rubber. E-learning is the future of education as it is interactive, interesting and entertaining way of learning, and will soon replace the paper books in the form of touch screen tablets.

  11. P2P文件分发的遗传算法优化研究%Research on Genetic Algorithm for Optimization of P2P Files Distribution



    P2P网络中节点加入和退出的随意性,影响着文件的可用性;为达到满意的性能,P2P社区必须对文件进行复制或替换.由此,提出引入遗传算法解决P2P文件可用性优化问题,它适合高效的、自适应的文件复制.为在组内成员节点之间复制源文件,将文件划分成大小相等的小片,依据链按时选择该节点的概率,将小片传送到成员节点;然后,每个节点向组内剩下的其它节点复制传播.该方法减少了文件复制的时间,提高了文件可用性.%The availability of a P2P file sharing system is heavily affected by the high churn rate of users. Since nodes are intermittently connected, the P2P community must replicate and replace files to achieve satisfactory per-formance. The Genetic Algorithms is applied in optimizing file availability in P2P files delivery. This algorithm is suitable for an efficient and adaptive replication of files. In order to replicate an original file among group member nodes, the file is divided into small chips of equal size, and each chip is transferred to a member node in proportion to the probability of selecting a link. Then, each node propagates it to the remaining nodes in the group. This method achieves reduced file replication time, and improves the files availability.

  12. 基于组群的P2P网络信誉机制%Based on group reputation system in P2P network

    蔡亮; 黄宜修


    针对P2P网络中基于个体的信誉机制的弊端,设计了双层结构信誉模型,即基于组群的P2P网络信誉机制.该机制在"物以类聚人以群分"的管理思想基础上,通过计算同一组群内节点间的信誉值不同组群中节点间的信誉值,以及组群间的信誉值的方法,从而实现P2P网络的良性自治.该机制设计了不同的节点间信誉计算方法,以满足各种网络的不同特性需求.随后通过模拟实验,验证了该机制的可行性和高效性,并分析了该机制适用的网络容量.%To solve the problems of based-on-peer reputation system in P2P network, this paper designed a double-deck reputation model, called based on group reputation system in P2P network.With the thought of birds of a feather flock together, by calculating a node' s reputation of another node in the same group, a node' s reputation of another node in different groups,and a group' s reputation of another group, the system fulfilled the implementation of P2P network' s well self-management.The system used different calculation methods to meet different networks' various requirements.By the experiments, the system was proved to be feasible and efficient.Furthermore, analyzed the applicable capacity of the system.

  13. A New Model of P2P Networks Virus Defense%一种新的P2P网络病毒防御模型

    王冠男; 王怀峰; 韩志杰; 段晓阳


    Currently, P2P networks has has a wide range of applications, such as file sharing, instant messaging and collaborative work, etc. It has a profound impact on network development as well as people's lives. At the same time, because of the characteristics of self-organization and decentralization of the network, P2P networks brought new challenges to the security of the current network. Aspects from the virus defense, the paper first introduced the current mainstream virus defense technologies, analyzed the advantages and disadvantages of these technologies, and then discussed the development trend of virus defense technology. Finally, in the full use of existing virus defense technologies, the paper presented a new program based on the characteristics of P2P network environment.%目前,P2P网络在文件共享、即时通信和协同工作等领域获得了广泛的应用,对网络的发展和人们的生活都产生了深远的影响.同时,P2P网络由于其自身自组织和非中心化的网络特点,给当前的网络安全带来了新的挑战.从病毒防御方面着手,首先介绍了目前主流的病毒防御技术并分析了这些技术的优缺点,然后对病毒防御技术的发展方向进行了探讨.最后在充分利用现有病毒防御技术的基础上,针对P2P网络环境的特性提出了一种新的方案.

  14. P2P网络仿真软件设计与实现%The Design and Implementation of Simulation Software in P2P Network



    P2P network technology provides for the computer network users to share,and effectively integrates the Internet resources,Internet applications based on Web pages into dynamic access and free interactive "mass information network." P2P development will affect the entire computer network development and information access mode.This article describes the P2P network simulation software features:expand coverage through a large number of nodes;allows multiple nodes to share the pressure on the server,and the data sent to the active node,the simulation software simulating real-time network status.%P2P网络技术能够为计算机网络用户提供共享,同时有效整合互联网资源,将基于Web网页的互联网应用转变成动态存取、自由交互的海量信息网络。P2P发展将影响整个计算机网络发展和信息获取模式。介绍了P2P网络仿真软件实现功能:可通过大量节点扩大覆盖范围,使多个节点能够分担服务器压力,并将这些数据传送到活跃节点,仿真软件可进行实时网络状态仿真。

  15. Research on Investigation and Prevention of Crime of P2P Loan%P2P网络借贷犯罪侦防研究



    P2P网络借贷作为互联网金融的一种创新模式,在当前得到蓬勃发展,但由于其目前尚无相关法律、法规以及行业标准对其进行规范和监管,使得一些受不法利益驱动的经营者利用P2P网贷平台私设资金池,违规动用资金,吸取高额利息,严重者甚至涉嫌非法吸收公众存款、集资诈骗以及洗钱等犯罪。对此,公安机关经侦部门应当积极应对,及时打击利用P2P网贷平台实施的犯罪案件,并配合相关行业、部门逐步建立起P2P网贷的监管平台和监管机制。%P2P loan, as a form of Internet financial innovation model, has gotten a vigorous development. However, because there is no relevant laws, regulations and industry standards, those, who want to make some illegal profits, tend to collect various kind of funds to get high interest rates, raise funds through illegal absorbing public deposits, fraud and even launder money. Therefore, the economic investigation department of the public security should deal with it in a timely manner, crack down on the crimes through using P2P network platform to implement crime, cooperate with related industries, departments, and gradually set up supervision platform and mechanism of P2P loan.

  16. Research of P2 P Overlay Network Based on JXTA Technology%基于JXTA技术的P2 P覆盖网络层的研究



    P2P network layer is introduced after making main module experiments on JXTA. This paper discusses the main functions of P2P overlay network layer, and then focuses on the analysis of the release mechanism, determines ways and means of the sensing func-tion through the introduction of JXTA strategy, introduces JXTA aware discovery process, and on this basis, realizes the management of peer notice life cycle. In this paper, the development of JXTA is achieved through P2P application layer, the functional release and compliance are realized by the function of the sensor, at last, the problem solving depends on the division of functions and roles of the sensor.%对JXTA进行主模块的实验后引入了P2P网络层。首先阐述P2P覆盖网络层的主要功能,再重点分析释放机制,通过引入JXTA发现策略,确定感应功能的方法和方式,并介绍JXTA感知发现过程,最后在此基础上实现对对等通知生命周期的管理。本文通过P2P应用层来实现对JXTA的开发,利用传感器的功能来实现功能的释放和达标,最后根据传感器功能和角色的划分解决问题。

  17. The pde2path add-on toolbox p2pOC for solving infinite time-horizon spatially distributed optimal control problems - Quickstart Guide -

    Uecker, Hannes


    p2pOC is an add-on toolbox to the Matlab package pde2path. It is aimed at the numerical solution of optimal control (OC) problems with an infinite time horizon for parabolic systems of PDE over 1D or 2D spatial domains. The basic idea is to treat the OC problem via the associated canonical system in two steps. First we use pde2path to find branches of stationary solutions of the canonical system, also called canonical steady states (CSS). In a second step we use the results and the spatial di...

  18. Isotope Shifts of the $6d\\,^2$D$_{3/2}\\,$ - $7p\\,^2$P$_{1/2}\\,$ Transition in Trapped Short-Lived $^{209-214}$Ra$^+$

    Giri, G S; Berg, J E van den; Böll, O; Dammalapati, U; van der Hoek, D J; Jungmann, K; Kruithof, W L; Müller, S; Portela, M Nuñez; Onderwater, C J G; Santra, B; Timmermans, R G E; Wansbeek, L W; Willmann, L; Wilschut, H W


    Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has been performed. The isotope shifts of the $6d\\,^2$D$_{3/2}\\,$ - $7p\\,^2$P$_{1/2}\\,$ transition in $^{209-214}$Ra$^+$ were measured, which are sensitive to the short range part of the atomic wavefunctions. The results are essential experimental input for improving the precision of atomic structure calculation. This is indispensable for parity violation in Ra$^+$ aiming at the determination of the weak mixing angle.

  19. Study of proton hole states in 1f/sub 7/2/ nuclei by the (p,2p) reaction at 46 MeV

    Bertrand, F.; Eisberg, R.; Ingham, D.; Makino, M.; Waddell, C.


    Proton hole states in the 1f/sub 7/2/ nuclei /sup 46/Ti, /sup 54/Fe, /sup 56/Fe, /sup 58/Ni, and /sup 60/Ni have been studied with the (p,2p) reaction with 46-MeV protons. The measured binding energies and angular correlations are consistent with the binding energies and orbital angular momentum assignments (1f/sub 7/2/, 2s/sub 1/2/, and 1d/sub 3/2/) obtained from proton pick-up reactions. 3 figures, 1 table.

  20. 可管理的P2P模式在IPTV中的应用%Application of a Manageable P2P Mode in IPTV System

    邓亮; 刘勇



  1. Ciberpiratería - sistemas peer to peer (p2p). Análisis de las sentencias en los casos Napster, Grokster, Morpheus, Streamcast y Kazaa

    Wilson Rafael Ríos Ruiz


    Los sistemas peer to peer (P2P) han trazado una línea o punto de quiebre en el escenario local e internacional de la industria musical, estableciendo nuevos escenarios donde los derechos de autores y titulares de derechos conexos se ven afectados por unos nuevos canales de distribución y comercialización de las obras mediante el denominado derecho de reproducción digital, el derecho de puesta a disposición establecido en el wct y el derecho a recibir una remuneración establecido en el wppt. E...

  2. Leveraging e-learning in medical education.

    Lewis, Kadriye O; Cidon, Michal J; Seto, Teresa L; Chen, Haiqin; Mahan, John D


    e-Learning has become a popular medium for delivering instruction in medical education. This innovative method of teaching offers unique learning opportunities for medical trainees. The purpose of this article is to define the present state of e-learning in pediatrics and how to best leverage e-learning for educational effectiveness and change in medical education. Through addressing under-examined and neglected areas in implementation strategies for e-learning, its usefulness in medical education can be expanded. This study used a systematic database review of published studies in the field of e-learning in pediatric training between 2003 and 2013. The search was conducted using educational and health databases: Scopus, ERIC, PubMed, and search engines Google and Hakia. A total of 72 reference articles were suitable for analysis. This review is supplemented by the use of "e-Learning Design Screening Questions" to define e-learning design and development in 10 randomly selected articles. Data analysis used template-based coding themes and counting of the categories using descriptive statistics.Our search for pediatric e-learning (using Google and Hakia) resulted in six well-defined resources designed to support the professional development of doctors, residents, and medical students. The majority of studies focused on instructional effectiveness and satisfaction. There were few studies about e-learning development, implementation, and needs assessments used to identify the institutional and learners' needs. Reviewed studies used various study designs, measurement tools, instructional time, and materials for e-learning interventions. e-Learning is a viable solution for medical educators faced with many challenges, including (1) promoting self-directed learning, (2) providing flexible learning opportunities that would offer continuous (24h/day/7 days a week) availability for learners, and (3) engaging learners through collaborative learning communities to gain

  3. How to Succeed at e-Learning

    Donnelly, Peter; Benson, Joel


    A basic guide to getting the best from e-learning for medical students, teachers and all healthcare professionals How to Succeed at e-Learning answers the needs of all healthcare professionals either starting or continuing their studies but not knowing where to begin with e-learning. It is a valuable guide for learners in undergraduate and postgraduate medicine as well as related health professionals and essential for teachers of medicine who are beginning to transfer from print to electronic teaching and need to understand effective methods of presentation.

  4. E-Learning Readiness in Public Secondary Schools in Kenya

    Ouma, Gordon O.; Awuor, Fredrick M.; Kyambo, Benjamin


    As e-learning becomes useful to learning institutions worldwide, an assessment of e-learning readiness is essential for the successful implementation of e-learning as a platform for learning. Success in e-learning can be achieved by understanding the level of readiness of e-learning environments. To facilitate schools in Kenya to implement…

  5. 一种对等网络文件污染抑制方案%Suppression scheme of file pollution for P2P network.



    File pollution is a common problem in P2P file sharing system. The similarity of biological immune system and P2P network is used to propose a suppression scheme for file pollution. Based on the immunity, an improved method of nodes similarity calculation and neighbor nodes selection is designed. It reduces the computation cost and improves the system performance. Simulation results show that the algorithm has high accuracy recognition and can suppress the spread of pollution file with lower communication costs.%文件污染是对等网络中存在的普遍问题.借鉴对等网络和生物免疫系统的相似性,提出一种基于免疫学习的文件污染抑制方案.基于免疫思想,设计了一种改进的节点相似度计算方法和邻居节点选择方案,减少了计算量,提高了系统性能.仿真实验表明,算法识别污染文件的精度较高,可以有效抑制污染文件的传播,并且通信开销较小.

  6. P2P网络中声誉信息分发算法%Reputation distribution algorithm in P2P network

    吴慧婷; 郭亚军; 王亮


    基于声誉的信任模型中,节点如何获取所需要的声誉信息是个关键问题.提出了一种基于蚂蚁的声誉信息分发算法.该算法通过模拟蚁群觅食的行为,实现了声誉信息在无集中式控制的P2P环境下的分发,解决了节点为建立信任关系获取声誉信息问题.仿真实验表明,该算法能使节点选择最佳路径获取声誉信息,降低了系统的负载,保证了节点获取声誉信息的可靠性和安全性.%In the reputation-based trust model,how to obtain reputation is a key problem.This paper proposes an algorithm for ant-based reputation distribution.This algorithm realizes reputation distribution in P2P network by modeling the ants' behavior of looking for food.The new approach can obtain reputation for building trust relationships in P2P network.Theoretical analysis and simulations prove that it can effectively improve the reliability and security and decrease network load.

  7. Research on node states in P2P network%P2P网络的节点状态研究

    鲁薇; 周竹荣; 邱玉辉


    对等网络中,研究节点的行为差异有利于实现区分服务,激励节点共享资源,提高系统的性能.用节点状态表示节点行为表现,提出P2P节点状态模型,描述状态的动态变化规律,并将模型与节点行为评价机制结合,确定节点状态的约束条件,提高模型的可用性.实验证明模型有效地支持区分服务,能促进节点的资源共享,具有良好的扩展性和实用性.%Analyzing nodes' behaviors in a Peer-to-Peer (P2P) network can effectively provide different services and encourage nodes to share resources, thereby improving the system performance. Using states to represent nodes' behaviors, P2P node state model was proposed to describe the process of states transition. The model was combined with nodes' behaviors assessment mechanism to specify conditions of node state. Experimental results show that the model, which has good scalability and availability, can achieve service differentiation and promote resources sharing by nodes.

  8. Formation of ultracold LiRb molecules by photoassociation near the Li (2s 2S1/2) + Rb (5p 2P1/2) asymptote

    Dutta, Sourav; Chen, Yong P


    We report the production of ultracold 7Li85Rb molecules by photoassociation (PA) below the Li (2s 2S1/2) + Rb (5p 2P1/2) asymptote. We perform PA spectroscopy in a dual-species 7Li-85Rb magneto-optical trap (MOT) and detect the PA resonances using trap loss spectroscopy. We observe several strong PA resonances corresponding to the last few bound states, assign the lines and derive the long range C6 dispersion coefficients for the Li (2s 2S1/2) + Rb (5p 2P1/2) asymptote. We also report an excited-state molecule formation rate (P_LiRb) of ~10^7 s^-1 and a PA rate coefficient (K_PA) of ~4x10^-11 cm^3/s, which are both among the highest observed for heteronuclear bi-alkali molecules. These suggest that PA is a promising route for the creation of ultracold ground state LiRb molecules.

  9. 一种基于HMM的P2P信任模型%A Trust Model for P2P Based on Hidden Markov Model

    张国容; 殷保群


    Aiming at the P2P networks security issues, this paper proposes the HMM-based P2P trust model, uses HMM to model the behavior of the peer. On the basis of this model, peer interaction result is used as the observation history. The probability distribution of peer behavior evaluated as trust can be calculated by HMM forward-backward algorithm. In consideration of the real time demand of trust evaluation, we proposes a model updating algorithm based on sliding window and forgetting factor.%针对 P2P网络中存在的安全问题,本文提出一种基于隐Markov模型(Hidden Markov Model, HMM)的P2P信任模型,采用HMM对节点行为进行建模,在此模型的基础上,利用节点交互结果作为观测历史,由前向-后向算法计算得到节点行为概率分布,作为节点的信任值评估。考虑到信任评估实时性的需求,文章还提出了一种基于滑动窗口和遗忘因子的模型更新算法。

  10. P2P-based Remote Control System of Mobile Robot%基于P2P的移动机器人远程控制系统

    王多林; 秦贵和; 徐海一; 陈筠翰


    This paper combines the remote control technology of robot and Internet, and designs a P2P based robot remote control scheme by introducing Network Address Translation(NAT) traversal technology. In the WAN simulation experiment, a platform of P2P mobile robot remote control system is built. The objective of peer-to-peer remote control and mobile robot feedback data display is achieved, making effective use of the limited bandwidth resource, and expanding the control range of remote control part to robot part. The proposed system shows great generality and real-time, in execution and time delay tests.%将机器人远程控制技术与Intemet相结合,引入NAT穿越技术,设计一种基于P2P结构的机器人远程控制方案,并在模拟广域网环境下,搭建P2P移动机器人远程控制系统平台.系统实现对移动机器人的远程P2P控制,将移动机器人反馈的视频数据加以显示,有效利用有限的带宽资源,扩大远程控制端对机器人的控制范围.运行及时延测试结果表明,该系统具有较好的通用性与实时性.

  11. Transmission Mechanism of P2P Streaming Media Model%P2P流媒体模型的资源传输机制

    陈文宇; 李维顺; 曾茹; 郭凌立


    针对流媒体的点播和直播服务,提出了基于P2P的流媒体应用层多播和点播的解决方案,构建了基于超级节点和普通节点的两层体系结构的视频流媒体模型.描述了模型的总体结构,分析了资源传输机制.基于校园网对模型进行了测试,测试结果表明,模型能够实现基于流媒体应用的多点数据快速互传.%For realizing the basic service of streaming media , video on demand and live video, we present a proposal of application layer multicast, video on demand, build a video frequency streaming media model with two kinds of peers, SP and peer based on P2P, describe the structure of model, analyze resources transmissions. Finally, some test records of this model are expressed with the table, that show a solution of ALM (application layer multicast) and video on demand with P2P model.

  12. 基于语义的对等网络检索机制%Efficient Semantic-based Content Search in P2P Network

    陈明; 鹿旸


    提出了一个基于语义的分布式对等覆盖网络S-Peer.网络中的节点基于语义信息聚类,并自组织成一个语义覆盖网络.S-Peer网络构造了一个一维语义空间,避免了高维语义空间的维护开销,提高了资源检索效率.实验结果证明了该算法的有效性和灵活性.%Content-based full-text search is a challenging problem in Peer-to-Peer (P2P) systems. A distributed P2P overlay network that supports semantic-based content searches, called S-Peer, is proposed. Peers in this overlay are grouped based on the semantics of their data, and self-organized as a semantic overlay network. To reduce overheads incurred by peer joining and leaving in a high-dimensional overlay network, peers are constructed as a one-dimensional semantic space that facilitates efficient routing. The results show the effectiveness, efficiency and scalability of the proposed system.

  13. A Hash-based P2P Overlay In Mobile Environment%移动环境中一种基于Hash的P2P覆盖网

    杨晓辉; 黄长俊; 许熠


    目前提出的大多数基于哈希(hash-based)的P2P网络都集中于固定的对等节点.当节点移动到网络中一个新的位置时,这种结构在消息传递等方面的效率就会下降.文章提出一种移动环境中的基于哈希的P2P覆盖网(Hash-based P2P Overlay in Mobile Environment,H-MP2P),允许节点在网络中自由移动.一个节点可通过P2P网络广播其位置信息,其他节点通过网络可以获知该节点的移动信息并进行定位.通过理论分析和实验可知H-MP2P在扩展性、可靠性和效率方面都可以取得较好的结果.可以很好的应用在移动环境中.

  14. Can E-learning change work practices?

    Noesgaard, Signe Schack


    -step model of intervention-based change. The model lists the key motivational drivers of employee persistence and commitment to change. The article illustrates e-learning as an assimilative learning catalyst and offers an overview of the scaffolding needed for advancing workplace practices. Ultimately......Stand-alone e-learning is unlikely to change work practices. This claim contrasts with a comprehensive body of research arguing that e-learning is at least as effective as face-to-face instruction in improving work performance. Such a comparison is, however, problematic. On the one hand, it relies...... on the premise that face-to-face instruction is effective in changing work behaviors. This article argues that instruction—whether e-learning, face-to-face, or a blend of both—cannot stand alone. Individualized on-the-job scaffolding of employees is needed for meaningful learning transfer and sustainable...

  15. Security issues in e-learning platforms

    Defta (Ciobanu Costinela – Luminita


    Full Text Available Security is an important issue in the actual educational context where e-learning increases in popularity and increasingly more people are taking online courses. The e-learning platforms are today production systems that need to be secured. To achieve a good level of security, there are many important elements that must be taken into account: authentication, access control, data integrity, content protection, etc. Information security can be obtained using methods such as cryptography and network protocols. In this paper we will highlight some key security issues that must be taken into consideration in developing and using an e-learning platform. We will also examine some security aspects of one of the most popular open-source e-learning systems: Moodle.

  16. Cognitive load theory and e-learning

    Van Mierlo, Christa; Jarodzka, Halszka; Kirschner, Femke; Kirschner, Paul A.


    Van Mierlo, C. M., Jarodzka, H., Kirschner, F., & Kirschner, P. A. (2012). Cognitive load theory in e-learning. In Z. Yan (Ed.), Encyclopedia of cyber behavior (pp. 1178-1211). Hershey, PA: IGI Global.

  17. An Approach To Personalized e-Learning

    Matteo Gaeta


    Full Text Available This paper focuses on the concept of personalized e-Learning for the computer science (or informatics education. Several authors have stated that personalization, in educational context, allows executing more efficient and effective learning processes. On the other side the use of Semantic Web technologies (e.g. ontologies is more and more often considered as a technological basis for personalization in e-Learning (the so-called self-regulated learning. In this paper we describe how personalization can be exploited in e-Learning systems, focusing on our proposal: the Intelligent Web Teacher (IWT. Therefore we present the evaluation of our personalization tools tested in real academic courses, where e-Learning activities are carried out to complement the traditional lectures.

  18. A European perspective on e-learning

    Dirckinck-Holmfeld, Lone


    E-learning at Work , edited by Anne Marie Kanstrup. Roskilde Universitetsforlag, pages Pp.15-29. 2004 Short description: Based on a survey of 149 European e-learning and adult vocational training projects, the author presents examples of how ICT facilitates a positive change and development...... of workplace-related learning. Abstract: Based on a survey of 149 European e-learning and adult vocational training projects, the author presents examples of how ICT facilitates a positive change and development of workplace-related learning.The chapter ends with a suggestion for a historical categorisation...... of e-learning, taking into consideration the technological development and the interplay with the changing learning paradigms. Key learnings from the projects indicate that ICT has already provided workplaces with a range of new tools for workplace learning. But the projects also seem to indicate...

  19. E-learning platforms and accessibility

    Daniela Adami


    Full Text Available Riflessioni sull’accessibilita’ delle piattaforme e-learning da parte di non vedenti. L’argomento viene affrontano raccontando l’esperienza di un corsista SSIS con difficolta’ visive.

  20. Climate Dimensions in E-Learning

    Gyöngyi Bujdosó


    Full Text Available In designing organization and environment,climate is a conventional conception. By an observation of Halpin, climate means the same for organizations as personality for individuals.This paper introduces the concept of cyber climate and some climate dimensions in e-learning. We deal with some new cyber climate dimensions that should be observed during designing e-learning materials,and provides some other important climate dimensions that should be taken into account while designing digital learning environments.


    Ahmad Ashari


    Full Text Available Personalization of Ontology Based E-learning System. Today, a form of technology known as Web 2.0 thatthoroughly supports web-to-web interactions is present. Interactions, such as information sharing in the forms ofdocument sharing (slideshare, picture sharing (flickr, video sharing (youtube, Wikis, and online networking (weblogand web-forum are principally accomodating community empowerment services. These factors cause the appearanceof social interaction through Internet as well as learning interaction and anywhere-anytime training which is recentlycalled e-Learning. Basically, e-Learning needs a self-employed learning method and learning habits that emphasize onthe learner as the most important role. However, e-learning system which is expected to boost the intensity of selfemployedlearning is uncapable to represent the importance. This is proven with the current e-Learning system inIndonesia that only accomodates the delivery of learning materials identical to all active learners, ignores the cognitiveaspects and does not offer any approach or experience of interactive self-learning and disregards the aspect of users’ability to adapt. The proposed e-learning system which is Web 2.0-based utilizes ontology as the representation ofmeaning of knowledge formed by the learner.

  2. Design of Customized Corporate E-Learning

    Tor Atle Hjeltnes


    Full Text Available Today's educational institutions deal increasingly with external commercial organizations in connection with e-learning deliveries. Production and delivery of e-learning to corporations is different from both traditional campus education and online distance education for independent online students. This study discusses challenges related to e-learning production and delivery for corporate customers. Consequently we have identified appropriate guiding principles that should contribute to the specification of amodel for design of customized corporate e-learning. We place particular emphasis on collaboration and stakeholder involvement, formative evaluation, utilization of technological opportunities, and relevant training for all parties involved. Moreover, we propose to benefit from concurrent design principles to achieve effective and efficient multidisciplinary collaboration in the design process. The study is based on primary data from two different projects where an educational institution offers e-learning for external corporate customers. In addition we collect secondary data from available research literature on e-learning and supplementary data from colleagues with long experience in this field.

  3. Impact of E-Learning Strategy on Students' Academic Performance ...

    Impact of E-Learning Strategy on Students' Academic Performance at Strathmore University, Kenya. ... Makerere Journal of Higher Education. Journal Home · ABOUT ... of e-learning. Keywords: Teaching and Learning; E-learning; ICT.

  4. E-learning Paradigms and The Development of E-learning Strategy

    Duus, Henrik Johannsen


    The e-learning area is characterized by a magnitude of different products, systems and approaches. The variations can also be observed in differences in the views and notions of e-learning among business people, researchers and journalists. This article attempts to disentangle the area by using e....... The selection of which paradigm to use in the development of an e-learning strategy may prove crucial for success. Implications for the development of an e-learning strategy in businesses and learning institutions are outlined....... economic and sociological theories, the theories of marketing management and strategy as well as practical experience gained by the author while working with leading edge suppliers of e-learning. On this basis, a distinction between knowledge creation e-learning and knowledge transfer e...

  5. P2P Network Traffic Classification Based on Decision Tree%基于决策树的P2P流量识别方法研究



    针对新型P2P业务采用净荷加密和伪装端口等方法来逃避检测的问题,提出了一种基于决策树的P2P流量识别方法.该方法将决策树方法应用于网络流量识别领域,以适应网络流量的识别要求.决策树方法通过利用训练数据集中的信息熵来构建分类模型,并通过对分类模型的简单查找来完成未知网络流样本的分类.实验结果验证了C4.5决策树算法相比较Na(i)ve Bayes、Bayes Network算法,处理相对简单且计算量不大,具有较高的数据处理效率和分类精度,能够提高网络流量分类精度,更适用于P2P流量识别.%To solve the question of new P2P application with payload encryption and camouflage to evade detection port,propose P2P network traffic classification based on decision tree. This method applies decision tree into the areas of network traffic to accommodate Internet traffic identification requirements. Decision tree method builds a classification model using information entropy in training data and classifies flows just by a simple search of the decision tree. Compared with Naive Bayes.Bayes network algorithm,experimental results demonstrate the C4.5 decision tree can achieve high classification accuracy with faster computational time by relatively simple and small calculation processing. It is more suitable to P2P traffic identification.

  6. P2P声誉系统中GoodRep攻击及其防御机制%GoodRep Attack and Defense in P2P Reputation Systems

    冯景瑜; 张玉清; 陈深龙; 付安民


    声誉系统由于其聚集评价的特点,为恶意节点提供了可乘之机.一些恶意节点合谋形成GoodRep攻击组,相互虚假夸大,进而在高声誉值的掩饰下危及P2P网络安全.提出了GoodRep的攻击模型及其防御机制--RatingGuard,并给出了该机制的数学描述和模块化实现过程.RatingGuard通过分析推荐节点之间的评价行为相似度,对推荐节点进行聚类划分和异常检测,识别出存在的GoodRep攻击组节点,从而帮助声誉系统排除GoodRep攻击组的干扰,仿真结果表明,RatingGuard在GoodRep攻击组的抵制方面效果显著,有效提高了声誉系统在面对GoodRep攻击时的恶意节点检测卒.%Reputation systems are playing critical roles in P2P networks as a method to assess the trustworthiness of peers and to combat malicious peers. However, the characteristic of aggregating ratings makes reputation systems vulnerable to be abused by false ratings, and thus offering opportunities for malicious peers. They can conspire with each other to form a collusive clique and unfairly increase the reputation of them. Under the cover of high reputation, malicious peers can masquerade as trusted ones and violate P2P networks arbitrarily. This attack model, called GoodRep, is described in this paper. In order to defend against GoodRep attack, the RatingGuard scheme is proposed to secure P2P reputation systems. This scheme is built with three functional modules: DC, DP and AD. The data collection (DC) module supports the collection of the previous rating data among raters. The data processing (DP) module measures the rating similarity of raters' activities by analyzing these data. To identify GoodRep cliques, the abnormal detection (AD) module detects the abnormalities through clustering partition technology. The experimental results show that our RatingGuard scheme is effective in suppressing GoodRep attack, and the reputation system with RatingGuard gains higher detection ratio of

  7. 一种具有常数度的无线P2P覆盖网络%A Wireless P2P Overlay Network with Constant Degree

    彭利民; 肖文俊


    Due to resource constraint and topology dynamism of wireless networks,P2P systems designed for wired networks may not be applicable to wireless networks.Based on semi-direct product of two groups in the algebra group theory,a new structured P2P system,which was the cayley graph with constant degrees,was presented.By using the Cayley-4DHT,different nodes were partitioned into corresponding groups based on nodes' identifiers,thus,neighbor nodes in the overlay networks were also neighbors in physical networks.Furthermore,by using cross-layer technology of wireless networks in the routing algorithm,the broadcast character of wireless networks was utilized for searching resources in P2P systems.Theory analysis and simulation results showed that the proposed Cayley-4DHT can achieve optimal performance of searching resources in wireless mesh networks.%由于无线网络中的资源受限性和拓扑动态性,有线网络上的已存在P2P系统很难直接应用到无线网络中。基于代数群论中的半直积方法,构造了一个具有Cayley图特性的常数度结构化P2P系统。Cayley-4DHT利用节点标识符将网络中的节点按照位置进行分组,使覆盖网络上邻近的节点在物理拓扑上也是相邻的,另一方面,通过在Cayley-4DHT的路由算法中嵌入无线网络中的跨层方法,使无线网络的广播特性在P2P资源搜索中得到了充分的利用。理论分析和模拟实验结果表明,Cayley-4DHT在无线m esh网络中,能提供较好

  8. (p, 2p) and (p, pn) reactions in /sup 6/Li and /sup 7/Li nuclei induced by medium-energy protons

    Vdovin, A.I.; Loshchakov, I.I.


    In the t-matrix approximation we analyze the (p,2p) and (p,pn) reactions and inelastic proton scattering in lithium nuclei. Quasielastic nucleon scattering and core polarization are taken into account coherently in the calculation of the reaction matrix element. We use the intranuclear nucleon wave functions calculated with the modified Elton shell model. The quasielastic scattering is described with the help of the nonlocal realistic t-matrix of free pp (pn) scattering. The calculations are compared with experimental data at the incident-proton energies 46, 47, 49, 70, and 100 MeV. It is shown that in contrast to the impulse approximation the t-matrix approximation reproduces the experimental results.

  9. Analysis of the /sup 16/O( p,2p)/sup 15/N reaction at a proton energy 50 MeV

    Boikova, N.F.; Vdovin, A.I.; Golikov, I.G.; Loshchakov, I.I.


    The /sup 16/O( p,2p)/sup 15/N reaction has been studied at a proton energy 50 MeV in the entire phase space, and in a symmetric coplanar geometry. Spectra differential in angle and energy have been obtained for the secondary protons and residual nuclei. The theoretical analysis of the data obtained has been carried out with inclusion of quasifree knockout and core polarization. In the quasifree approximation we have used the nonlocal realistic t matrix of free proton-proton scattering. The coupling constants which determine virtual excitations in the region of giant resonances of /sup 15/N for E1 and E2 transitions have been found. Agreement with experiment is obtained only under the condition of coherent summation of the amplitudes of the two processes considered.

  10. Study of fission barriers in neutron-rich nuclei using the (p,2p) reaction. Status of SAMURAI-experiment NP1306 SAMURAI14

    Reichert, Sebastian [TU Munich (Germany); Collaboration: NP1306-SAMURAI14-Collaboration


    Violent stellar processes are currently assumed to be a major origin of the elements beyond iron and their abundances. The conditions during stellar explosions lead to the so called r-process in which the rapid capture of neutrons and subsequent β decays form heavier elements. This extension of the nuclei stops at the point when the repulsive Coulomb energy induces fission. Its recycling is one key aspect to describe the macroscopic structure of the r-process and the well known elemental abundance pattern. The RIBF at RIKEN is able to provide such neutron rich heavy element beams and a first test with the primary beam {sup 238}U was performed to understand the response of the SAMURAI spectrometer and detectors for heavy beams. The final goal is the definition of the fission barrier height with a resolution of 1 MeV (in σ) using the missing mass method using (p,2p) reactions in inverse kinematics.

  11. 自适应的P2P网络路由方法研究%Research of adaptive routing method on P2P network

    吴亚辉; 邓苏; 黄宏斌


    在分析一系列P2P网络资源发现方法的基础上,提出了一种基于查询的P2P网络路由方法(Query-based Routing Method in P2P network,QRM方法).在该方法中,节点会记录收到的查询以及满足该查询的节点,在这些节点中,优先存储那些距离较远的节点.仿真实验表明,随着查询的增多,该方法能有效地提高查询效率.

  12. Off-the-energy-shell pp scattering in the exclusive proton knockout 12C(p,2p) reaction at 392 MeV

    Sumi, T T


    The triple differential cross section (TDX) for the 12C(p,2p) proton knockout reaction from the 1p3/2 single-particle state measured at 392 MeV is investigated by nonrelativistic distorted wave impulse approximation (DWIA) with accurate treatment of the kinematics of the colliding two protons and effects of in-medium modification to the matrix elements of the proton-proton (pp) effective interaction. Some simplifying approximations made in previous studies with DWIA are examined. The off-the-energy-shell matrix elements of the pp effective interaction are shown to play an essential role in describing the asymmetric two peaks of the measured TDX corresponding to the kinematics in which the momentum transfer is fixed.

  13. An unusual presentation of a customs importation seizure containing amphetamine, possibly synthesized by the APAAN-P2P-Leuckart route.

    Power, John D; Barry, Michael G; Scott, Kenneth R; Kavanagh, Pierce V


    During the analysis of an Irish customs seizure (14 packages each containing approximately one kilogram of a white wet paste) were analysed for the suspected presence of controlled drugs. The samples were found to contain amphetamine and also characteristic by-products including benzyl cyanide, phenylacetone (P2P), methyl-phenyl-pyrimidines, N-formylamphetamine, naphthalene derivatives and amphetamine dimers. The analytical results corresponded with the impurity profile observed and recently reported for the synthesis of 4-methylamphetamine from 4-methylphenylacetoacetonitrile [1]. The synthesis of amphetamine from alpha-phenylacetoacetonitrile (APAAN) was performed (via an acid hydrolysis and subsequent Leuckart reaction) and the impurity profile of the product obtained was compared to those observed in the customs seizure. Observations are made regarding the route specificity of these by-products.

  14. 网络借贷平台P2P模式探索%Research on the P2P Network Lending Platform Model

    郭卫东; 李颖


    In recent years, with the continuou s innovation and development of the internet and mobile internet and financial instrument, a variety of network lending platforms are growing rapidly at home and abroad; the P2P lending model, one of the important innovation models, is attracting more and more attention and is accepted by the academic field. Comparing platforms in China and those in other countries, we can see that there are some similarities in terms of operation principles;but because of the differences in credit and legal environment, there are some problems with China’s P2P network lending platforms from the aspects of trading pattern and risk control and we lagged behind in terms of development stage and future development space, and how to standardize this industry is the problem demanding urgent solution. Considering the current situation of P2P network lending platforms development at home and abroad, to better promote the development of P2P network lending platforms, we should, first, perfect the related laws and strengthen industrial supervision; second, we should strengthen the certification of platforms and prevent risk; third, we should improve the operation pattern and spread risk over broader fields;and fourth, we should improve the financial transparency of platforms.%近年来,随着互联网及移动互联网的发展以及金融工具的不断创新,网络借贷平台在国内外快速兴起,P2P借贷模式作为互联网金融一种重要的创新模式,也逐渐得到了学术界的高度关注和认可。对比国内外P2P在线借贷平台可以发现,与国外平台相比,国内P2P在线借贷平台在经营理念上有相似之处,但由于信用和法律环境的差异,导致我国P2P在线借贷平台在交易模式、风险控制等方面问题较多,在发展阶段与未来空间上也显示出很大的差距, P2P行业规范问题的解决刻不容缓。综合国内外P2P在线借贷平台发展现状

  15. 基于Gossip协议的P2P流媒体系统%A P2P streaming media system based on Gossip protocol



    在分析P2P(peer-to-peer)流媒体系统的典型模型的基础上,设计一种基于Gossip协议的P2P网络流媒体直播系统. 该系统可以为每个节点独立地选择良好的伙伴节点,节点的自组织能力能够有效地减轻服务器的压力. 实验表明,该系统能够充分利用自身节点的剩余带宽,动态适应网络拓扑的变化,提高流媒体直播的服务质量.

  16. Systems Analysis of the VoIP Based on P2P Overlay%基于P2P重叠网的VoIP系统实现

    廖小成; 龙昭华; 杨令


    随着网络技术的日益发展和普及,VoIP(Voice Over Internet Protocol)应用增长迅速,出现了很多新的应用技术,其中最具有代表性的是P2P(Peer to Peer)重叠网的应用;能够将VoIP技术与P2P结合无疑是一种新的有价值的尝试.文中在分析了现有P2P通信机制的基础上,选用Chord协议并结合SIP协议实现一种基于P2P模式的VoIP系统.

  17. P2P Network Characteristic Model Based on Flow%基于流的P2P网络特性模型

    陈宝钢; 许勇; 胡金龙


    利用从实际网络获得的数据,提出基于流的P2P网络特性模型.采用图形方法和概述统计识别样本所服从的分布族,使用可视化图形方法和假设检验方法对统计分布模型进行拟合优度检验.分析结果表明,流持续时间的分布模型可以用对数正态分布精确表示,混合对数正态分布可以有效拟合流长和流传输速率分布的分布模型,且P2P应用的流长和流持续时间没有高度相关的关系.%This paper proposes a P2P network characteristic model based on flow obtained from the actual network. It uses diagram and summary statistics process to recognize the distribution of sample, designs the statistical distribution model, and uses visual graphic method and the hypothesis testing method to do goodness of fit test for statistical distribution model. Analysis results show that the lognormal distribution can accurately express the flow duration, while flow size and flow transmission rate can be reasonably modeled by lognormal mixture distribution, however P2P application flow size and flow duration are not highly related to each other.

  18. 民营经济融资的P2P模式探析%p2 p Model Analysis of private Economy Financing

    李俊; 张运书


    The private economy plays an important role in national economy and social life,and also in raising taxes and employment,but the existed financing difficulties of private economy has become the development bottleneck. By analyzing the present situation of defects in the private economy itself,the higher proportion of internal financing,high threshold,low willingness to lend commercial bank loans financing,combining P2P financing mode innovation of in-ternet financial circumstances,this paper proposes that the advantage of P2P financing model in low threshold,lower transaction costs,fund use efficiency higher advantages is the first choice of solving private economic financing diffi-culties.%民营经济在国民经济和社会生活中均扮演着重要角色,在增加税收及就业方面发挥了重要作用,但民营经济存在的融资困境是其发展瓶颈。通过对民营经济自身制度的缺陷、内源融资比重过高、商业银行贷款门槛高、放贷意愿低等融资现状的分析,并结合互联网金融大环境下P2 P融资模式的创新,提出利用P2 P融资模式在门槛低、交易成本低、资金运用效率高等方面的优势是解决民营经济融资困境的首要选择。

  19. Analysis on P2P Platform Risk and Countermeasures%P2P平台的风险与应对策略



    P2P网络贷款是一种将互联网的优势和民间借贷有机融合的新兴商业模式,依赖其便利、经济的特点,迎合了中国民间小微贷款不畅的现实需求,繁荣了我国的借贷市场,对我国的经济发展起到了积极的促进作用.但因为监管不当、行业不够规范、法律法规滞后,出现了集资诈骗等一系列不良问题,引起社会上的普遍质疑.如何面对P2P平台的风险及挑战,找出应对策略,是摆在我们面前亟待解决的问题.%P2P network loan is a new business model with the Internet advantages and the organic integration of private lending, rely on its convenience and economic characteristics, meet the Chinese folk realities of small and micro loans to poor demand, the prosperity of our country's loan market, to China the economic development has played a positive role in promoting. But because of improper regulation, the industry is not standardized, laws and regulations lag, there has been a series of adverse financial fraud and other problems, caused widespread questioning society. How to face the risks and challenges of P2P platforms, find the key to solute the problem. It's a challenge we need to deal with in front of us.

  20. 基于分布式对等架构的Web应用防火墙%Web Application Firewall Based on Distributed P2P Architecture

    姚琳琳; 何倩; 王勇; 赵帮


    In order to make up the insignificance of Web Application Firewall(WAF) with single node in detection efficiency and stability, a WAF based on distributed and P2P architecture is designed and implemented by using reverse proxy technology. Reverse proxy technology is used to response the Web request. Aiming to implementing P2P architecture, the same program is run on each node. Master and auxiliary nodes are determined dynamically by demands. The master node has the characteristics of session keeping and load balance, and auxiliary nodes detect messages by expert library and plug-in components. Experimental results show that the system can effectively prevent attacks from application layer, and it is more efficient and stable than single node.%为弥补单节点Web应用防火墙(WAF)在检测效率和稳定性方面的不足,采用反向代理技术,设计并实现一个基于分布式对等架构的WAF.通过反向代理响应客户端请求,各个节点运行相同的程序以实现对等架构,主节点与辅助节点可根据需求动态调整,主节点具有会话保持和负载均衡功能,辅助节点采用专家库和插件协同检测报文.实验结果表明,该应用防火墙能够有效阻止应用层攻击,相比单节点响应更加迅速和稳定.

  1. E-Learning and Economic Development

    Kelly CAREY


    Full Text Available E-Learning and Economic Development Kelly CAREY West Valley College Saratoga, CA, USA Stanko BLATNIK Institute for Symbolic Analysis and Development of Information Technologies Velenje, SLOVENIA ABSTRACT In this article, our experience in the development and realization of e-Learning courses in Slovenia is described and discussed. Slovenia, the most developed republic of former Yugoslavia, became an EU member in May 2004. In 1991, after its independence from Yugoslavia, Slovenia’s transition to a free market economy resulted in lost jobs and an unemployment rate of 12%. In 1999, as the Institute for Symbolic Analysis and Development of Information Technologies, located in Velenje, Slovenia, we decided to offer several online courses to help unemployed people gain the skills and knowledge needed for employability in information technology. We drew on our previous experience teaching online courses at Sarajevo University after the Bosnian war and on the experience of West Valley College from Saratoga, Silicon Valley in e-Learning. Over the last four years, we organized and delivered e-Learning courses in digital media design and production, with good results. Several students found jobs and changed their perception and attitude as they became more self-confident. We believe e-Learning can efficiently enhance lifelong learning and support economic development, especially in new member countries transitioning from former socialistic to free market economies.

  2. P2P 网络借贷监管的博弈分析%An Analysis of Online Peer-to-Peer Lending Regulation from the Perspective of Game Theory



    Since the online peer to peer lending was brought in China in 2007,it has developed rapidly. Risk control is the foundation for the development of the industry.As the lending platform frauds frequently with uncertain risks,it is urgent to have a proper regulation of P2P.At present,China Banking Regulatory Commission has been determined as the regulator of P2P.However,contents of supervision are not set in China.Therefore,based on the game relationship between the regulator and P2P companies,the regulator should promote the P2P industry development by self-regulation,setting the threshold and strict penalties and so on.%自2007年 P2P 借贷模式第一次出现, P2P 网络借贷平台诈骗频发以及各种风险的不确定性,都使得对 P2P 的监管刻不容缓。目前,我国 P2P 监管已经确定归口于银监会,但是具体监管内容还未出台。因此,针对 P2P 行业中监管机构和被监管机构的博弈关系,监管部门需要通过加强自律、设立入行门槛、建立严苛的处罚机制等手段来规范 P2P 网络借贷行业的发展。

  3. Making a Case for E - learning: Experiences in E-learning at ...

    The study under discussion was a case study carried on 26 freshman students at the ... self directed learning, to providing resources and supportive collaboration from a distance. ... Key Concepts: E- learning, information and communications technology skills, effective practice with e- learning, pedagogy, learning activity ...

  4. Collaboration in E-Learning: A Study Using the Flexible E-Learning Framework

    Vandenhouten, C.; Gallagher-Lepak, S.; Reilly, J.; Ralston-Berg, P.


    E-Learning remains a new frontier for many faculty. When compared to the traditional classroom, E- Learning requires the talents of many team members from a variety of departments as well as the use of different teaching and learning strategies. Pedagogy as well as team configurations must change when moving to the online environment. As a result,…

  5. eLearning Hands-On: Blending Interactive eLearning with Practical Engineering Laboratory

    Kiravu, Cheddi; Yanev, Kamen M.; Tunde, Moses O.; Jeffrey, Anna M.; Schoenian, Dirk; Renner, Ansel


    Purpose: Integrating laboratory work into interactive engineering eLearning contents augments theory with practice while simultaneously ameliorating the apparent theory-practice gap in traditional eLearning. The purpose of this paper is to assess and recommend media that currently fulfil this desirable dual pedagogical goal.…

  6. Data mining techniques for e -learning

    Irina IONIȚĂ


    Full Text Available Data Mining (DM, sometimes called Knowledge Discovery in Databases (KDD, is a powerful new technology with great potential to help companies focus on the most important information in the data they have collected via transactions. In the education field, the prediction of students learning performance, detection of inappropriate learning behaviours, and development of student profile may be considered e-learning problems where data mining can successfully solve them. In this paper, the authoress analyses the possibilities to apply data mining techniques in e-learning context, to predict the students’ status referring to their activities and the interest in using advanced tutoring tools. The experiments were performed on the basis of data provided by an e-learning platform (Moodle regarding the logging parameters of students enrolled on Interactive Tutoring Systems discipline during the second semester of current year.

  7. e-Learning research: emerging issues?

    Helen Beetham


    Full Text Available e-Learning research is an expanding and diversifying field of study. Specialist research units and departments proliferate. Postgraduate courses recruit well in the UK and overseas, with an increasing focus on critical and research-based aspects of the field, as well as the more obvious professional development requirements. Following this year's launch of a National e-Learning Research Centre, it is timely to debate what the field of study should be prioritising for the future. This discussion piece suggests that the focus should fall on questions that are both clear and tractable for researchers, and likely to have a real impact on learners and practitioners. Suggested questions are based on early findings from a series of JISC-funded projects on e-learning and pedagogy.

  8. Motivation og refleksion i e-learning

    Majgaard, Gunver; Thisted, Anni


    , spilelementer (serious gaming) og opslugthed (flow) og dermed et grundlag for at stimulere refleksion og motivation. Målet med artiklen er at give inspiration til praktikere, som udvikler e-learning til individuelt brug, og som ønsker at gøre e-learning engagerende og motiverende og samtidig opnå væsentlig...... læringsdybde.   Artiklen giver en introduktion til udvalgte teoretikere, som arbejder med motivation og opslugthed og er krydret med eksempler fra en undersøgelse af en individuel e-learning-applikation fra den finansielle sektor, som understøtter social stimulation. Applikationen er udviklet med henblik på...

  9. Investigating Possibilities for E-Learning

    Ørngreen, Rikke; Nielsen, Janni; Tweddell Levinsen, Karin


    of and with theLundbeck Institute, human computer interaction issues as well as the first designideas are disseminated. As such the report does not provide a thorough frame ofreferences within the HCI-area (Human Computer Interaction) and e-learning area,as these are seen as implicit for the understanding...... process in the pre-phase and among thepartners, also clarifying how we found the focus areas of the pre-phase, known as theproject map (in section 1.1). The next chapter (chapter 0) provides a detailed accountof the pre-phase project results, taking a holistic view to the e-learning project...... at the Lundbeck Institute, investigating the current activities, the lessons learnedwithin Continuing Medical Education (CME), the visions of e-learning and thepeople it is targeted at. Chapter 4 and 5 provides the more external perspectivesbeing based on investigations of learning models and pedagogical tools...

  10. The effectiveness of e-learning

    Noesgaard, Signe Schack; Ørngreen, Rikke


    to the findings of the literature study. The study suggests that it is difficult to use e-Learning to improve teaching performance, as participating teachers can apply several strategies to avoid substantially changing their work-related practices. Furthermore, the study shows that only using the fulfilment......A structured search of library databases revealed that research examining the effectiveness of e-Learning has heavily increased within the last five years. After taking a closer look at the search results, the authors discovered that previous researchers defined and investigated effectiveness...... in multiple ways. At the same time, learning and development professionals within public and private organisations are increasingly being asked to prove the effectiveness of their learning and development initiatives. This paper investigates the effectiveness of e-Learning through an integrative review...

  11. Teaching Syllogistics Using E-learning Tools

    Øhrstrøm, Peter; Sandborg-Petersen, Ulrik; Thorvaldsen, Steinar


    This paper is a study of various strategies for teaching syllogistics as part of a course in basic logic. It is a continuation of earlier studies involving practical experiments with students of Communication using the Syllog system, which makes it possible to develop e-learning tools and to do l...... involving different teaching methods will be compared.......This paper is a study of various strategies for teaching syllogistics as part of a course in basic logic. It is a continuation of earlier studies involving practical experiments with students of Communication using the Syllog system, which makes it possible to develop e-learning tools and to do...... learning analytics based on log-data. The aim of the present paper is to investigate whether the Syllog e-learning tools can be helpful in logic teaching in order to obtain a better understanding of logic and argumentation in general and syllogisms in particular. Four versions of a course in basic logic...

  12. A European perspective on e-learning

    Dirckinck-Holmfeld, Lone


    that focus is on designing the technical tools rather than on the use of tools for e-learning in general, where ICT is just one integrated element among many: objective, motivation, ways to learning, profession, workplace etc. The rojects also reveal that different European countries move at different paces...... of workplace-related learning. Abstract: Based on a survey of 149 European e-learning and adult vocational training projects, the author presents examples of how ICT facilitates a positive change and development of workplace-related learning.The chapter ends with a suggestion for a historical categorisation...... of e-learning, taking into consideration the technological development and the interplay with the changing learning paradigms. Key learnings from the projects indicate that ICT has already provided workplaces with a range of new tools for workplace learning. But the projects also seem to indicate...

  13. Programming Tasks in E-Learning

    Krzysztof Barteczko


    Full Text Available The article discusses the goals of teaching programing languages, kinds of programming tasks, evaluation criteria and methods for solutions checking. Many aspects of the assessments need, especially within e-learning framework, dedicated tools for solutions checking. Considered are the possibilities and methods for their automatic application. Integration of automatic evaluation tools in a consistent system is proposed. Through the rich content of the interaction with students such a system would lead to increase of e-learning quality. Examples presented in this article apply to programs and tools for the Java platform.

  14. Principles of e-learning systems engineering

    Gilbert, Lester


    The book integrates the principles of software engineering with the principles of educational theory, and applies them to the problems of e-learning development, thus establishing the discipline of E-learning systems engineering. For the first time, these principles are collected and organised into the coherent framework that this book provides. Both newcomers to and established practitioners in the field are provided with integrated and grounded advice on theory and practice. The book presents strong practical and theoretical frameworks for the design and development of technology-based mater

  15. Knowledge Management in E-Learning Systems

    Rodica MIHALCA


    Full Text Available Current knowledge management systems focus on knowledge acquisition, storage, retrieval and maintenance. Yet, for that knowledge to be operational, to become knowledge rather than information, requires internalization and learning. E- learning systems and courseware, on the other hand, are all too often monolithic and inert and fail to facilitate the development and sharing of knowledge. In this paper we discuss some aspects about knowledge providing and present our research in this field through an e-learning system for major risks management.

  16. Improving e-learning by Emotive Feedback

    Sharp, Robin; Gjedde, Lisa


    This paper considers the use of feedback with emotive elements in order to improve the efficiency of e-learning for teaching complex technical subjects to the general public by stimulation of implicit learning. An example is presented, based on an effort to investigate the current level of IT sec......This paper considers the use of feedback with emotive elements in order to improve the efficiency of e-learning for teaching complex technical subjects to the general public by stimulation of implicit learning. An example is presented, based on an effort to investigate the current level...

  17. Teaching Syllogistics Using E-learning Tools

    Øhrstrøm, Peter; Sandborg-Petersen, Ulrik; Thorvaldsen, Steinar


    This paper is a study of various strategies for teaching syllogistics as part of a course in basic logic. It is a continuation of earlier studies involving practical experiments with students of Communication using the Syllog system, which makes it possible to develop e-learning tools and to do...... learning analytics based on log-data. The aim of the present paper is to investigate whether the Syllog e-learning tools can be helpful in logic teaching in order to obtain a better understanding of logic and argumentation in general and syllogisms in particular. Four versions of a course in basic logic...... involving different teaching methods will be compared....

  18. eLearning--Theories, Design, Software and Applications

    Ghislandi, Patrizia, Ed.


    Chapters in this book include: (1) New e-Learning Environments: e-Merging Networks in the Relational Society (Blanca C. Garcia); (2) Knowledge Building in E-Learning (Xinyu Zhang and Lu Yuhao); (3) E-Learning and Desired Learning Outcomes (Ralph Palliam); (4) Innovative E-Learning Solutions and Environments for Small and Medium Sized Companies…

  19. Research on P2P Lending Model and Regulatory Issues%我国P2P借贷模式及其监管问题研究



    由于我国对金融业的改革开放相对其他产业存在某种程度的保守,金融抑制,金融资源配置不合理等现象在很大领域内普遍存在,以致难以发挥金融作为经济发展转型的润滑剂推动器作用。当前,一方面,急需资金的广大中小微企业和个体经营工商业户难以从国有大型金融机构获得金融支持;另一方面,我国出现了大量拥有闲置资金需要出借的中产富裕阶层。因此,作为金融中介,连结资金需求和供给双方的个人与个人之间借贷(P2P)民间金融机构就出现了。本文通过梳理归纳目前国内几种主流P2P借贷平台运营模式,从多角度提出对其将来更加规范科学合理发展的监管建议。%Since the reform and opening of China's financial sector relative to other industries exist to some extent conservative, financial repression, irrational allocation of financial resources and other phenomena in a large common areas, making it difficult to play the role of financial lubricant pusher transformation of economic development . Currently, on the one hand, micro-needed funds for medium and small enterprises and self-employed industrial and commercial households is difficult to obtain financial support from the large state-owned financial institutions; hand, China appears to have a lot of idle funds needed to lend affluent middle class. Therefore, as financial intermediaries, lending (P2P) links between the individual and the individual financial needs of both supply and private financial institutions have emerged. This article is currently combing through induction of several major domestic P2P lending platform business model, its future regulatory proposals put forward rational development of more standardized science from multiple perspectives.

  20. P2 P网贷平台的法律风险及对策%On the Legal Risks and Countermeasure of P2P Platform



    Since P2P lending platform was introduced into our country,it has provided debt financing for the majority of small micro enterprises conveniently.However,the Ponzi scheme and dissimilation in such platform caused legal risks due to the lack of legislative regulations.Some platforms construct the cash pool and provided relevant guarantee ,which makes them exceed the legal limitation ,and put the pub-lic fund into the non-protected field.To prevent such legal risk,the legal regulation and credit system must be built.We should develop the access qualification,the trust of public fund ,the reveal of market information and the estimate of credit ,so that the P2P platform can attain a stantard operation.%P2P网络借贷平台的发展为广大小微企业的债权融资提供了便捷,但由于缺乏有效的法律监管,其亦给“庞氏骗局”和经营模式的异化提供了空间。这些法律风险主要表现为网贷机构“脱媒”经营,自建资金池或提供关联性担保,使所募资金脱离监管,进入无风险屏障的交易流程,导致公众资金丧失安全保障。为防止此类法律风险,应兼顾监管制度和征信制度的建设,通过准入资格、资金托管、信息披露以及信用评价体系的完善,为P2 P平台的运营提供规范化指引。

  1. 基于WCF和对等网络的即时通信软件的设计与开发%Design and development of instant communication software based on WCF and P2P network



    This paper introduces the construction and technical elements of a new generation of distributed WCF framework . Meanwhile , it analyzes the basic principles of Peer-to-Peer network and meshing characteristics , and develops a real-time commu-nication software based on the analysis of the advantages of WCF and P2P network . At last , it summarizes the basic steps for using the . NET platform to develop P2P applications , and elaborates the P2P network which is an ideal platform for P2P application devel-opment .%介绍了 Microsoft 用于构建分布式面向服务架构的新一代框架 WCF ( Windows Communica-tion Foundation )的体系结构与技术要素;同时分析了对等网络( Peer-to-Peer network )的基本原理和网格化特性。在分析 WCF 和 P2P 网络优点的基础上开发了一个即时通信软件,总结了使用。 NET 平台开发 P2P 应用的基本步骤,阐述了对等网络是开发 P2P 应用的理想平台。

  2. 基于IP-P2P的校园网资源共享平台的研究%Study of Campus Network Resource Sharing Platform Based on IP-P2P



    In order to adapt to highly dynamic and the efficient search, this paper puts forward thestructured P2P networks based on index (IP-P2P), which has the double-indexing mechanism, the index of such a layer is body composition of a structured P2P network, another layer is formed by ordinary peer P2P network. Then it realizes campus network resource sharing platform using IP-P2P, the test results are proved the effectiveness.%为了能够适应高度动态性,同时又能进行高效搜索,文章提出基于索引的结构化P2P网络IP-P2P(Index-PeerP2P)模型,它具有双层索引机制,一层是由索引对等体组成的有结构P2P网络,另一层是由普通对等体组成P2P网络,然后实现了基于IP-P2P校园网资源共享平台的方案并通过测试证明了该平台的有效性.

  3. Policy Formulation and Networks of Practice in European eLearning: The Emergence of a European E-Learning Area

    Salajan, Florin D.


    This article discusses the emergence of a European E-Learning Area (EELA) as a consequence of three factors that can be observed in the e-learning developments over the past decade. The first factor consists of the carving of a policy sector in e-learning via formal instruments such as the eLearning Programme, the Lifelong Learning Programme and…

  4. e-Learning: The Student Experience

    Gilbert, Jennifer; Morton, Susan; Rowley, Jennifer


    The paper draws on in-depth qualitative comments from student evaluation of an e-learning module on an MSc in Information Technologies and Management, to develop a picture of their perspective on the experience. Questionnaires that yielded some basic quantitative data and a rich seam of qualitative data were administered. General questions on…


    Stiffy Sunny


    Full Text Available Weblog which was initially coined as daily diaries turned into place containing information directly from a source with richer context. Evolution of a blog has lead to different kinds of blog such aspersonal blogs, corporate blog, by genre, by media type etc. Blog has invaded the electronic learning. ELearning is an interactive teaching and learning e-environment, where teachers and students communicate about their subject. Information about various subjects is provided as e-learning blogs, based on the user’s interest. E-Learning has become much more interactive compared to the classroom learning. Students can post their queries in the form of comments, these comments can be viewed by other students and teachers and they could reply back as comments. Rich content such as image, video,audio can also be passed as comments. The challenge in the highly polluted web environment is to identify the best e-learning blog from the existing various blogs. The identification of the best e-learning blog depends on certain criterion such as considering the previous history and personal interest of the user, word of mouth, the rate of the blog on the web and. In the paper proposed, appropriate algorithms are chosen to incorporate the proposed ideology.

  6. Social Networking Services in E-Learning

    Weber, Peter; Rothe, Hannes


    This paper is a report on the findings of a study conducted on the use of the social networking service NING in a cross-location e-learning setting named "Net Economy." We describe how we implemented NING as a fundamental part of the setting through a special phase concept and team building approach. With the help of user statistics, we…

  7. Moodle and e-learning Tools

    Zahraa F. Muhsen


    Full Text Available Online interactions provide a large knowledge exchange on variety kinds of information exchanged between users. There are many software systems available that provide online learning systems, this type of software expressed by forms, commercial or open source software. This paper is focused on Moodle, it explained the comparative study that done by many recent researches, it also shows the different between Moodle and other learning management systems, in order to discover their strengths and limitations, discusses different points in these systems. Moodle has been adopted by many universities and organizations the entire world because it offers a large accusable set of tools, and many components was developed without a specific design documentation including its security services. This paper shows the comparative study between Moodle and other e-learning systems; it aimed to discover the best and most suitable choice of e-learning system. We have fined the optimal e-learning platform required to our e-learning university system, and it is Moodle, according to the used by many Universities around the word and from many works that has been done to date that encourages the used and develops this type of LMS.

  8. Constructivist E-Learning in Higher Education

    Bognar, Branko; Gajger, Vesna; Ivic, Vlatka


    The use of e-learning has been recommended at all levels of the educational system, thus in higher education as well, but it is very often reduced to downloading teaching materials from the teachers' websites. Students rarely participate in forums discussing some teaching topics, and they even less use the learning management system in their…

  9. E-Learning Concepts in Higher Education

    Sorensen, Elsebeth Korsgaard; Mathiasen, Helle; Dalsgaard, Christian

    The main aim of the symposium is to investigate, at both a theoretical and practical level, the quality and sustainability of a variety of models and key concepts of how communication and collaborative e-learning communities may be successfully developed, implemented and supported in higher...

  10. PACS infrastructure supporting e-learning

    Mildenberger, Peter, E-mail: [University Medicine Mainz, Johannes Gutenberg-University Mainz, Langenbeckstr 1, Mainz (Germany); Brueggemann, Kerstin; Roesner, Freya; Koch, Katja; Ahlers, Christopher [University Medicine Mainz, Johannes Gutenberg-University Mainz, Langenbeckstr 1, Mainz (Germany)


    Digital imaging is becoming predominant in radiology. This has implications for teaching support, because conventional film-based concepts are now obsolete. The IHE Teaching File and Clinical Study Export (TCE) profile provides an excellent platform to enhance PACS infrastructure with educational functionality. This can be supplemented with dedicated e-learning tools.

  11. E-learning and education in radiology

    Pinto, Antonio, E-mail: [Department of Diagnostic Imaging, A. Cardarelli Hospital, I-80131 Naples (Italy); Brunese, Luca, E-mail: [Department of Health Science, Faculty of Medicine and Surgery, University of Molise, I-86100 Campobasso (Italy); Pinto, Fabio, E-mail: [Department of Diagnostic Imaging, A. Cardarelli Hospital, I-80131 Naples (Italy); Acampora, Ciro, E-mail: [Department of Diagnostic Imaging, A. Cardarelli Hospital, I-80131 Naples (Italy); Romano, Luigia, E-mail: [Department of Diagnostic Imaging, A. Cardarelli Hospital, I-80131 Naples (Italy)


    Purpose: To evaluate current applications of e-learning in radiology. Material and methods: A Medline search was performed using PubMed (National Library of Medicine, Bethesda, MD) for publications discussing the applications of e-learning in radiology. The search strategy employed a single combination of the following terms: (1) e-learning, and (2) education and (3) radiology. This review was limited to human studies and to English-language literature. We reviewed all the titles and subsequent the abstract of 29 articles that appeared pertinent. Additional articles were identified by reviewing the reference lists of relevant papers. Finally, the full text of 38 selected articles was reviewed. Results: Literature data shows that with the constant development of technology and global spread of computer networks, in particular of the Internet, the integration of multimedia and interactivity introduced into electronic publishing has allowed the creation of multimedia applications that provide valuable support for medical teaching and continuing medical education, specifically for radiology. Such technologies are valuable tools for collaboration, interactivity, simulation, and self-testing. However, not everything on the World Wide Web is useful, accurate, or beneficial: the quality and veracity of medical information on the World Wide Web is variable and much time can be wasted as many websites do not meet basic publication standards. Conclusion: E-learning will become an important source of education in radiology.

  12. e-Learning Business Research Methods

    Cowie, Jonathan


    This paper outlines the development of a generic Business Research Methods course from a simple name in a box to a full e-Learning web based module. It highlights particular issues surrounding the nature of the discipline and the integration of a large number of cross faculty subject specific research methods courses into a single generic module.…

  13. Knowledge Management in E-Learning Practices

    Yilmaz, Yucel


    Thanks to extension of IT in educational activities, the difficulties based on time and space are disappearing and the management and the execution of these activities can be implemented more effectively and beneficially. Even though there are significant developments about e-learning both in academic and professional platforms, there are some…

  14. E-learn Computed Tomographic Angiography

    Havsteen, Inger; Christensen, Anders; Nielsen, Jens K


    BACKGROUND: Computed tomographic angiography (CTA) is widely available in emergency rooms to assess acute stroke patients. To standardize readings and educate new readers, we developed a 3-step e-learning tool based on the test-teach-retest methodology in 2 acute stroke scenarios: vascular...

  15. Editorial: Knowledge management and E-Learning

    Minhong Wang; Stephen J. H. Yang


    Welcome to the inaugural issue of Knowledge Management & E-Learning: An International Journal (KM&EL).In this inaugural editorial we would like to introduce the goals of the journal and provide the basis for why this journal is needed, and outline the scope and structure of the journal.

  16. E-Learning: Between Augmentation and Disruption?

    Heilesen, Simon B.; Josephsen, Jens


    Based on a framework for analysis combining diffusion theory, content layer analysis and sense making, this paper discusses the theme of "e-learning as augmentation or disruption" from the point of view of technological innovation. Two cases of on-campus blended learning at Roskilde University, Denmark, are introduced to illustrate the…

  17. E-Learning in Postsecondary Education

    Bell, Bradford S.; Federman, Jessica E.


    Over the past decade postsecondary education has been moving increasingly from the classroom to online. During the fall 2010 term 31 percent of U.S. college students took at least one online course. The primary reasons for the growth of e-learning in the nation's colleges and universities include the desire of those institutions to generate…

  18. Social Networking Services in E-Learning

    Weber, Peter; Rothe, Hannes


    This paper is a report on the findings of a study conducted on the use of the social networking service NING in a cross-location e-learning setting named "Net Economy." We describe how we implemented NING as a fundamental part of the setting through a special phase concept and team building approach. With the help of user statistics, we…

  19. E-learning in virtual communities

    Rothkrantz, L.J.M.


    In recent years many systems for distance learning have been developed. Even though students have access to learning material any time and any place, current tools for e-learning still have their limitations. The main shortcoming, compared to real life learning is the limited opportunity for human l

  20. A Personalized e-Learning Framework

    Alhawiti, Mohammed M.; Abdelhamid, Yasser


    With the advent of web based learning and content management tools, e-learning has become a matured learning paradigm, and changed the trend of instructional design from instructor centric learning paradigm to learner centric approach, and evolved from "one instructional design for many learners" to "one design for one learner"…

  1. E-learning to train staff in Danish hospitals - three genres of e-learning.

    Bygholm, Ann


    This paper presents a study of the use of e-learning in education and training of hospital staff in Denmark, in particular in relation with the implementation of electronic patient records (EPR). The study consists of a survey mapping the dissemination and main experience from using e-learning in Danish hospitals. The study shows a widespread use and a considerably agreement on the potentials of e-learning in education and training of hospital staff, but also problems and doubtfulness concerning the actual role of e-learning in the overall educational and organizational strategy for the hospital. The majority of hospitals use some sorts of computer-based training program to support the staff in acquiring necessary knowledge to operate the EPR. I argue that a more differentiated understanding is needed in order to realize the potentials and direct the use of e-learning in hospitals. Three genres of e-learning which differ in regards to qualification addressed are identified and I claim that a more explicit understanding of the differences between them is needed in order to guide the choice of e-learning of hospital staff.

  2. Gestion efficace de s\\'eries temporelles en P2P: Application \\`a l'analyse technique et l'\\'etude des objets mobiles

    Gardarin, Georges; Yeh, Laurent; Zeitouni, Karine; Butnaru, Bogdan; Sandu-Popa, Iulian


    In this paper, we propose a simple generic model to manage time series. A time series is composed of a calendar with a typed value for each calendar entry. Although the model could support any kind of XML typed values, in this paper we focus on real numbers, which are the usual application. We define basic vector space operations (plus, minus, scale), and also relational-like and application oriented operators to manage time series. We show the interest of this generic model on two applications: (i) a stock investment helper; (ii) an ecological transport management system. Stock investment requires window-based operations while trip management requires complex queries. The model has been implemented and tested in PHP, Java, and XQuery. We show benchmark results illustrating that the computing of 5000 series of over 100.000 entries in length - common requirements for both applications - is difficult on classical centralized PCs. In order to serve a community of users sharing time series, we propose a P2P imple...

  3. 非结构化P2P网络中IACO资源搜索算法%IACO resources search algorithm in unstructured P2P network

    FANG Pei; YAN Xiang-long; LIANG Zi; WU Xiao-jun


    To solve the problems of low efficiency and more redundant messages in unstructured P2P network resources search,this paper proposed an ant colony optimization based on interest factor(IACO).It gave full consideration to the effects of node value of resou%针对非结构化P2P网络中资源搜索效率低、冗余消息较多的情况,提出一种基于兴趣因子的蚁群优化算法(IACO)。该算法充分考虑了节点价值对资源搜索的影响,在传统蚁群算法中引入节点的兴趣因子,以动态调整节点价值和信息素在计算转发概率时的权重关系,有效地指导了资源查询路径的生成。仿真结果表明,该算法可以显著提高资源查询的成功率,同时在一定程度上减少了网络中的冗余消息量。

  4. P2P网络中Chord搜索算法的改进研究%Improvement of Chord search algorithm research in P2P network

    CAO Lei; ZHANG Yu-mei; WU Xiao-jun; YIN Jia-le; GUO Hai-liang; WANG Ting


    为解决P2P网络中Chord算法众多节点性能不一、节点频繁离开和加入制约系统性能的问题,提出了基于信息相关度的分组改进算法。该算法通过引入节点信息相关度的概念,对原Chord进行信息相关度的一个分组调整。从每个组选出两个超级节点组成超级组,同时为每个节点增加了逆时针路由,在两个超级节点顺逆两个方向上选择出最短路径进行查找。实验表明,改进后的算法使得系统的性能和适应性都得到了加强,提高了Chord在对等网中的查找效率。%In P2P network, performances of many nodes in Chord algorithm are inconsonant. The problem that nodes leave and join frequently will restrict the performance of system seriously.Therefore,this paper presented grouping improved algorithm based on related d

  5. 高速网络下P2P流量识别研究%Research on P2P Trafifc Identiifcation Under the High Speed Network

    穆筝; 吴进; 许书娟


    Network trafifc classiifcation refers to classify the lfow which mixed with a variety of applications in accordance with the protocol which lfow used. Network trafifc classiifcation has been one of the hot spot in all walks of life. Research on network trafifc classiifcation can provide the basis to design the next generation of high performance network protocol, can provide the gist for network management and network traffic scheduling, can provide support for network attack protection and trafifc cleaning. This paper analyzes the network trafifc identiifcation methods in nowadays mainstream sand summarized the lfow classiifcation technology development present situation and research results. According to current situation of rapid growth of P2P traffic and the characteristics of high-speed network trafifc, focuses on the binary classiifcation method of P2P trafifc which under the high-speed networks. In this paper, data stream can be divided into P2P trafifc and the normal network trafifc by the trafifc identiifcation methods based on the behavior of the transport layer ifrstly, and dynamically generate marked characteristic of the training set according to the results of the classification. Effectively avoids the sample set which is used by the classiifcation algorithm is not accurate because of the network data lfow changed. And then put forward a kind of P2P trafifc identiifcation method based on C4.5 decision tree, this method only need to calculate several packets which in a data lfow, and then the network traffic identification is completed. Don't need to concern of single or double direction of the data flow, data encryption, etc. Experiments show that the recognition accuracy of this method is high; the computational complexity is low, suitable for high-speed network traffic identiifcation.%网络流量分类是指将混有各种应用的流量按照流量所使用的协议进行分类.网络流量分类一直是各界共同关注的热点之一.研究

  6. 一种P2P流媒体数据调度策略的研究%Research on Data Scheduling in P2P Streaming Media

    钟子豪; 钟广超; 张明军; 许克静


    Focus on the shortage of existing P2P streaming media scheduling algorithm in acquire priority of data block and peers service ability, introduced a scheduling algorithm base on urgency and scarcity degree of data block, and a algorithmic method to calculate service ability of neighbor peers that can compensates the shortage effective, reduce start delay of streaming media and make the playing fluent, can also keep the load balance of streaming media systems.%针对现有P2P流媒体调度策略在确定数据块的调度优先权以及节点服务能力时存在的不足,提出了一种以数据块的紧迫度和稀缺度为基础的调度优先权的计算方法,以及提出了邻居节点的服务能力的计算方法,经过仿真试验证明可知该策略能有效的解决现有算法的不足,使流媒体启动延迟较小、播放流畅,且能使流媒体系统负载均衡.

  7. 公钥体系的混合式P2P信任模型%Hybrid Structure P2P Trust Model Based On PKI

    周计文; 李巍海; 刘刚; 侯宾


    A hybrid structure peer-to-peer (P2P) trust model based on public key infrastructure (PKI) is designed. Hierarchical management system is adopted to authenticate the peers. The security of communications between peers is guaranteed by Public Key Infrastructure (PKI).The peer's reputation is synthetically inspected by local trust, recommendation trust and global trust. The mathematics method to implement the model is given. Simulations results show that the proposed algorithm can provide nodes with high transaction success rate.%设计公钥体系的混合式P2P网络信任模型.采用层次化管理体系对节点进行认证,公钥体系保障节点间通信的安全性.通过局部信任、推荐信任、全局信任综合考察节点的可信情况.给出了模型的数学实现方法 .仿真结果 表明,模型能够有效提高节点的交易成功率.

  8. A Window-Based, Server-Assisted P2P Network for VoD Services with QoE Guarantees

    Noé Torres-Cruz


    Full Text Available We describe a Peer-to-Peer (P2P network that is designed to support Video on Demand (VoD services. This network is based on a video-file sharing mechanism that classifies peers according to the window (segment of the file that they are downloading. This classification easily allows identifying peers that are able to share windows among them, so one of our major contributions is the definition of a mechanism that could be implemented to efficiently distribute video content in future 5G networks. Considering that cooperation among peers can be insufficient to guarantee an appropriate system performance, we also propose that this network must be assisted by upload bandwidth from servers; since these resources represent an extra cost to the service provider, especially in mobile networks, we complement our work by defining a scheme that efficiently allocates them only to those peers that are in windows with resources scarcity (we called it prioritized windows distribution scheme. On the basis of a fluid model and a Markov chain, we also developed a methodology that allows us to select the system parameters values (e.g., windows sizes or minimum servers upload bandwidth that satisfy a set of Quality of Experience (QoE parameters.

  9. Ciberpiratería - sistemas peer to peer (p2p. Análisis de las sentencias en los casos Napster, Grokster, Morpheus, Streamcast y Kazaa

    Wilson Rafael Ríos Ruiz


    Full Text Available Los sistemas peer to peer (P2P han trazado una línea o punto de quiebre en el escenario local e internacional de la industria musical, estableciendo nuevos escenarios donde los derechos de autores y titulares de derechos conexos se ven afectados por unos nuevos canales de distribución y comercialización de las obras mediante el denominado derecho de reproducción digital, el derecho de puesta a disposición establecido en el wct y el derecho a recibir una remuneración establecido en el wppt. El entorno digital se convierte en el nuevo amo y señor de la industria del entretenimiento y en el nuevo objetivo tanto de las normas de propiedad intelectual que buscan proteger los intereses de los creadores, como de sus futuros desarrollos. Sin embargo, también es el lugar preferido de los viejos y actuales infractores de los derechos de autores y titulares de derechos.

  10. Ciberpiratería - sistemas peer to peer (p2p. Análisis de las sentencias en los casos Napster, Grokster, Morpheus, Streamcast y Kazaa

    Wilson Rafael Ríos Ruiz


    Full Text Available Los sistemas peer to peer (P2P han trazado una línea o punto de quiebre en el escenario local e internacional de la industria musical, estableciendo nuevos escenarios donde los derechos de autores y titulares de derechos conexos se ven afectados por unos nuevos canales de distribución y comercialización de las obras mediante el denominado derecho de reproducción digital, el derecho de puesta a disposición establecido en el wct y el derecho a recibir una remuneración establecido en el wppt. El entorno digital se convierte en el nuevo amo y señor de la industria del entretenimiento y en el nuevo objetivo tanto de las normas de propiedad intelectual que buscan proteger los intereses de los creadores, como de sus futuros desarrollos. Sin embargo, también es el lugar preferido de los viejos y actuales infractores de los derechos de autores y titulares de derechos.

  11. 基于P2P技术的多媒体网络会议模型%P2P-based Conference Model for Multimedia Network

    周梁; 陈世峰; 林晓鹏; 郭东辉


    本文提出了一种基于P2P技术的多媒体网络会议设计模型,该模型采用Chord协议组织节点和实现节点路由定位,将服务器的职能分布到P2P Overlay的各节点上,并根据节点的异构性将它们分为普通节点和超级节点,各节点根据自身能力各尽所能,使网络资源得到充分利用,可有效解决C/S模式下中央服务器带来的性能瓶颈问题.仿真实验表明该网络会议系统模型具有负载均衡、易于扩展和高效的资源定位等特点.

  12. CLIMANDES climate science e-learning course

    Hunziker, Stefan; Giesche, Alena; Jacques-Coper, Martín; Brönnimann, Stefan


    Over the past three years, members of the Oeschger Centre for Climate Change Research (OCCR) and the Climatology group at the Institute of Geography at the University of Bern, have developed a new climate science e-learning course as part of the CLIMANDES project. This project is a collaboration between Peruvian and Swiss government, research, and education institutions. The aim of this e-learning material is to strengthen education in climate sciences at the higher education and professional level. The course was recently published in 2015 by Geographica Bernensia, and is hosted online by the Peruvian Servicio Nacional de Meteorología e Hidrología (SENAMHI): The course is furthermore available for offline use through USB sticks, and a number of these are currently being distributed to regional training centers around the world by the WMO (World Meteorological Organization). There are eight individual modules of the course that each offer approximately 2 hours of individual learning material, featuring several additional learning activities, such as the online game "The Great Climate Poker" ( Overall, over 50 hours of learning material are provided by this course. The modules can be integrated into university lectures, used as single units in workshops, or be combined to serve as a full course. This e-learning course presents a broad spectrum of topics in climate science, including an introduction to climatology, atmospheric and ocean circulation, climate forcings, climate observations and data, working with data products, and climate models. This e-learning course offers a novel approach to teaching climate science to students around the world, particularly through three important features. Firstly, the course is unique in its diverse range of learning strategies, which include individual reading material, video lectures, interactive graphics, responsive quizzes, as well as group

  13. Modern technologies of e-learning

    G. A. gyzy Mamedova


    Full Text Available E-learning constitutes a significant competition to traditional education in many countries and has become a major tool for the modernization of education and economic growth. For the development and implementation of successful e-learning systems, we need technologies that allow working with them for any number of users, providing a good learning environment. The article provides an overview of the technologies used in foreign universities for managing e-learning, such as 3D technologies in training programs, interactive technologies, personalization of learning using cloud computing and big data technologies. It is shown that today quite a large number of software and hardware development was created and introduced, implementing various mechanisms of introducing information technologies in the educational process. One of such developments is the use of adaptive technologies in the learning process, allowing the student to adapt to the training material, choose the suitable method of mastering the material, and adjust the intensity of training at different stages of the learning process. Another development of information technologies in education is the use of cloud computing, allowing access to educational resources for teachers, students, and managers of the education system. It was revealed that the use of cloud technologies leads to a significant decrease in material costs for the purchase of expensive equipment and software, educational content from the cloud can be accessed from any device (laptop, smartphone, tablet, etc. and at a convenient time for the learner, it is enough to have Internet connection and a browser. In the e-learning environment, there are many different types of data, both structured and unstructured, processing of which is difficult to implement using traditional statistical methods. For the processing of such data technologies of processing big data are used such as NoSQL and Hadoop. The article shows that the

  14. Talking on the Characteristics of P2P Technology and Network Security Issues%论P2P技术特点与网络安全问题



    P2P technology has been developing quite fast,widely used in a variety of network activity, but there are many security issues of P2P technology.This author primarily on P2P network security analysis and discussion.%P2P技术近年来发展得相当快,广泛应用各种网络活动中,但目前P2P技术存在诸多安全问题。本文笔者主要对P2P网络安全问题进行分析与探讨。

  15. 移动P2P网络资源查找策略研究最新进展%Review of Resources Search Strategy for Mobile P2P Networks

    宋人杰; 高越


    伴随着无线网络技术和P2P覆盖网络技术的迅猛发展,资源查找策略是移动P2P的核心问题,本文对移动P2P资源查找策略的论述。%As the wireless network technology and the rapid development of P2P overlay network technology, architecture and search strategy is the core issue of mobile P2P resources, this paper mainly discusses the present mobile P2P resources search strategy is discussed.

  16. On the Influence Factors of Credit Risk of Online P2P Lending in China:Based on an Empirical Analysis by the Ranking Selection Model%我国 P2P 网络借贷信用风险影响因素研究基于排序选择模型的实证分析

    肖曼君; 欧缘媛; 李颖


    Online P2P (peer-to-peer)lending,is microfinance transactions by people lending to each other,with the aid of online platforms of electronic business.As a new financial model of folk loan business conducted with the Internet technology,it has a higher credit risk.This paper uses the ranking selection model to analyze the influencing factors of the credit risk of online lend-ing based on data from some P2P sites extracted by excel VBA Data Mining,and the results showed that:personal characteristics,credit variables,historical performance,loan information each had a marked positive influence on the credit risk of online lending.We found that the infor-mation provided by websites for investors to avoid credit risk did not play a substantive role.%P2P(peer-to-peer)网络借贷是一种借助网络平台,由个人与个人间互为借贷双方的小额借贷交易。它作为互联网与民间借贷相结合的新兴金融模式,具有较高的信用风险。采用排序选择模型,基于 ex-celVBA 数据挖掘技术截取多个 P2P 网站数据,对平台信用风险的影响因素进行实证分析,结果表明:个人特征、信用变量、历史表现、借款信息分别对网络借贷信用风险存在正向影响,由此发现网站提供的信息对投资者避免信用风险没有起到实质作用。

  17. Keefetifan E-Learning sebagai Media Pembelajaran (Studi Evaluasi Model Pembelajaran E-Learning SMK Telkom Sandhy Putra Purwokerto)

    Numiek Sulistyo Hanum


    Penelitian ini bertujuan untuk (1) mendeskripsikan standar mutu pelaksanaan e-learning sebagai media pembelajaran yang efektif; (2) mengidentifikasi keefektifan perencanaan pembelajaran e-learning; (3) mengidentifikasi keefektifan perancangan dan pembuatan materi pembelajaran e-learning; (4) mengidentifikasi keefektifan metode penyampaian pembelajaran e-learning; (5) mengidentifikasi keefektifan pelaksanaan dan interaktivitas pembelajaran e-learning; (6) men-gidentifikasi keefektifan evaluasi...

  18. 采用排名反馈的P2P名誉评价模型%Reputation Model with Feedback of Ranking for P2P Systems

    李治军; 姜守旭; 李晓义


    Some peers may receive service and information of low-quality from other peers in peer-to-peer (or P2P) networks. Reputation evaluation is the normal method used to reduce the above phenomena. P2P reputation,based on score feedback, is defective because it can not distinguish the malicious feedback from the erring feedback returned by honest peers. It needs long time to converge the reputation and evaluate feedback. It is inflexible and unnatural to depict the reputation of a peer through a lot of numbers. In fact, the reputation is used to determine the rank of the peers. A reputation model called RbRf (reputation based ranking feedback) based on the rank feedback,is presented in this paper. Mathematical models unfolds in this paper show that the influence of erring feedbacks attenuates with the exponential function of RbRf. The influence of unintended malicious feedbacks is attenuated with the polynomial function in RbRf. The intended collusive feedbacks are counteracted by the correct information introduced by these feedbacks. In summary, the defection of score feedback, such as the need of a second evaluation of the trust of feedback, does not in RbRf any longer because the RbRf uses rank feedback, instead of score feedback, and the RbRf can achieve a better effect when resisting to malicious attacks. All results are verified by experimental data.%P2P网络中的节点很可能从另外的节点那里收到质量很差的服务和信息,名誉评价是解决该问题的常见方法.基于评分反馈的P2P名誉计算机制存在下述缺点:无法区分恶意评价和诚实节点给出错误评价间的差别;需要对评分可信度进行二次评价,使名誉计算速度减慢;用数字来表示节点名誉的方式不够自然.实际上,名誉评价的用途是确定节点可信度的相对顺序.因此,提出了一种基于排名反馈的P2P名誉评价机制RbRf(reputation based ranking feedback).针对RbRf和其上的恶意攻击进行了数学建模和

  19. Efficient Writing Mechanism for P2P File System%P2P文件系统的高效写机制

    邱元杰; 刘心松


    为了解决P2P文件系统中网络延迟太大和副本数量太多以至写入速度太低问题,提出了基于核心副本集的并行写机制.定义了核心副本集的概念,并详细论述了核心副本集的选择算法.提出了并行写的机制,并给出了机制中写乱序问题、并行度控制问题和写正确性检查问题的解决办法.测试结果表明,核心副本集能够在写的过程中自动选择;在高网络延迟的环境下,其写入速度随并行度增加而提高,且在相同环境下,其写入速度是普通写入机制的6倍.%In P2P file system, writing file is inefficient because a large number of copies and high network delay. In this paper, a parallel writing mechanism based on core copy set (PWMBCS) is proposed to solve those problems. Paralleling writing is given out to deal with network delay. The control algorithm for write order and parallel degree also is given out in this paper. As shown in many tests, the core copy set can form with writing, and PWMBCS is six times more than normal writing mechanism.

  20. Interest-based search scheme for unstructured P2P network%基于兴趣域的对等网络动态搜索机制

    陈香香; 吴开贵; 陈明


    Because of the inflexibility, the search mechanism of unstructured P2P network cannot search cross-domain files efficiently. For this problem, this paper proposed an efficient search algorithm that based on interest-domain. The algorithm divided the network into different domains according to the different classification of files that each node shares. Used budget value and TIL (time to live) value to control the number of searched nodes and the search depth. Posed different search schemes for different search types. Experiment results show that with 50 percent nodes are covered, and the search efficiency is kept about 35 percent. In other words, the algorithm meets the inquiry needs of most users. The efficiency is relatively stable and higher than the typical search mechanism.%针对非结构化P2P搜索机制不够灵活、不能有效解决跨域文件搜索的问题,提出一种基于兴趣域的非结构化P2P动态搜索算法.此算法根据每个节点共享的文件类型的差异,将网络进行分域,在分域的基础上利用预算值和TTL(time to live)值来控制搜索节点的数目和搜索的深度,对不同类型的搜索采用不同的搜索策略.实验表明,该搜索算法的节点覆盖率在50%左右,搜索效率保持在35%左右,即算法能够有效地满足用户的查询需求,效率比较稳定且高于当前典型的搜索算法.

  1. Credit Model based on P2P Electronic Cash System Bitcoin%基于P2P网络Bitcoin虚拟货币的信用模型

    郑书雯; 范磊


    Digital currency, with the functions of transactions media, price evaluation, value saving and payment means, is an ideal resource exchange mode. Bitcoin is pure P2P digital cash and could meet the possible requirement of decentralization and contain the inflation of money. Based on this, the trust mechanism is introduced into the system so that nodes could build their reputation and thus help is proposed, which allows the nodes with more-than-needed appliers and thus to help them build their trust evaluation optimize the whole economic environment. So a protocol money to provide trust amount and capital turnover for%电子货币具有交易媒介、价值标准、价值储藏和支付手段的职能,十分适合点对点(P2P)系统的资源交换方式。比特币(Bitcoin)是一种纯P2P的虚拟货币,能够满足去中心化,预估货币流通总量,遏制通货膨胀的可能的需求。在此基础上重新引入信用机制,能够使得节点建立自己的信用,帮助优化整个货币金融环境。为此提出一种协议,允许有富余资金的节点给需要资金的节点提供信用额度,从而为其他节点提供资金周转,也为他们建立一定的信用评级。

  2. P2P-based Short Video Sharing System%一种基于P2P的短视频分享系统

    陈卓; 李彦


    Online short video sharing is reshaping the way people watching videos, so this paper presents sharing policies mainly adopts the Client/Server architecture, which can result huge bandwidth pressure at streaming server. A P2P based online short video sharing System IShare is proposed, which combines viewing interests of users and social network characteristic of short videos, which can share short videos between users. IShare mainly includes interest based peers clustering and streaming source peers searching. Experimental results show IShare has a high efficient streaming source peers searching ability and can greatly reduce the bandwith consumption of streaming server.%现有在线短视频分享策略通常采用C/S架构,给视频服务器带来较大的带宽压力.为此,提出一种采用点对点方式的在线短视频分享系统IShare,该系统结合用户点播偏好和视频文件之间的社会网络特性实现视频分享.IShare主要包括基于点播兴趣的节点分簇和视频数据源节点的查找2个核心技术.实验结果表明,IShare具备较好的视频数据源节点查找能力,可降低视频服务器带宽资源消耗.

  3. 移动P2P网络中协同缓存的研究%Research on cooperative caching in mobile P2P network

    季美丽; 王新华


    This paper deploys P2P system in mobile campus network and then presents an effective cooperative caching strategy. Access control strategy uses "threshold value" and relationship of location between two nodes to select the data to be cached. Cache replacement strategy chooses the data which will be replaced by the "Cost" function that is decided by three factors: data popularity, data size and distance between two regions. Data consistency strategy combines benefits of Plain-Push and Pull-Every-time and then makes improvements. Two sets of simulation experiments show that cooperative caching strategy achieves better performance in terms of reducing latency, decreasing overhead of network communication and improving the hit ratio.%在移动园区网环境中部署了P2P系统并提出了一种协同缓存策略.接入控制策略利用“阈值”和节点的位置关系选择缓存的数据.缓存替换策略利用价值函数“Cost”选择要替换掉的数据,该函数考虑了数据的被访问频率、大小及区域之间的距离这三个因素.数据一致性策略结合了Plain-Push和Pull-Every-time方案的优点并做了改进.通过两组模拟实验验证了这种协同缓存策略在降低时延、减少网络通信开销、提高缓存命中率方面具有较好的性能.

  4. Study on the Construction of Student Loan Mechanism of P2P%P2P助学借贷机制建设探究



    国家助学贷款制度的施行已历经十六年,但在推行过程中存在着政策性目标与商业性目标对立、制度设计规定缺乏人性化和灵活性以及回收机制不完善,违约率高等问题.通过谋求助学金融制度创新,推动助学金融服务社会化是健全和完善我国当前助学贷款政策体系的一条新路径.将P2P这一互联网金融创新引入到助学借贷领域,能有效缓解和弥补当前国家助学贷款制度存在的主要问题和不足,从而为贫困大学生营造更为良好宽松的助学借贷环境.%The implementation of the national student loan system has gone through sixteen years, but there have been some problems in the process of its implementation:the opposition between policy targets and business goals, lack of humanization and flexibility, recovery mechanisms are inadequate, high default rates and so on. By seeking student financial system inno-vation, and promote the socialization of student financial services is a new path to improve and perfect our current student loan policy system. P2P the Internet financial innovation will be introduced to the student lending, can effectively relieve the main problems and make up for the shortcomings existing in the current national student loan system , so as to poor college students to create a more comfortable student lending environment.

  5. Effective Mind Maps in E-learning

    Petr Kedaj


    Full Text Available This article presents the role of mind maps in creating well-structured e-learning materials and courses, which has become very important with increasing influence of new technologies and alternative study modes. The basic principles of mind mapping are described, including structural components of mind maps, and examples of practical use cases. Based on the identified lack of existing methodical frameworks for creating interactive mind maps for e-learning, we present a set of rules and metrics, which can help to identify points of ineffectiveness, and eliminate redundancies. This framework for creating effective mind maps and its implications are described in details with help of illustrative figures and textual description. The maps that has been created in accordance with this methodology are clear and comprehensible.

  6. Naturalistic Inquiry in E-Learning Research

    Shirley Agostinho


    Full Text Available In this article, the author explains how and why one particular qualitative research approach, the naturalistic inquiry paradigm, was implemented in an e-learning research study that investigated the use of the World Wide Web technology in higher education. A framework is presented that situates the research study within the qualitative research literature. The author then justifies how the study was compliant with naturalistic inquiry and concludes by presenting a model for judging the quality of such research. The purpose of this article is to provide an example of how naturalistic inquiry can be implemented in e-learning research that can serve as a guide for researchers undertaking this form of qualitative inquiry. As such, the focus of the article is to illustrate how methodological issues pertaining to naturalistic inquiry were addressed and justified to represent a rigorous research approach rather than presenting the results of the research study.

  7. E-Learning for Power Quality

    Bauer, Pavol; Nagy, Istvan

    E-learning with pre-solved animations can provide a better understanding of the status and different network options, compared to complex simulation or a set of equations. In this paper, examples of such animations for e-learning for power quality are presented. Different network options in a centralized or distributed power system and power electronics based compensators are introduced in the form of a new web-based, software learning tool. Power flow congestion and the impact of power electronic compensators on the system, including detailed operations of power electronic based compensators are presented. These compensators include SVCs, Statcom and UPFC presented in this paper. Using these animated tools, both system level and component level operation of these devices are presented. Further the frequent solutions of power factor correction (PFC) applied on low power level of several hundred watts are treated in the paper.

  8. Experience Effect in E-Learning Research

    Wu, Bing; Xu, WenXia; Ge, Jun

    This study is a productivity review on the literature gleaned from SSCI, SCIE databases concerning experience in E-Learning research. The result indicates that the number of literature productions on experience effect in ELearning research is still growing from 2005. The main research development country is Croatia, and from the analysis of the publication year, the number of papers is increasing to the peaking in 2010. And the main source title is British Journal of Educational Technology. In addition the subject area concentrated on Education & Educational Research. Moreover the research focuses on are mainly survey research and empirical research, in order to explore experience effect in E-Learning research. Also the limitations and future research of these research were discussed, so that the direction for further research work can be exploited

  9. Innovation Research in E-Learning

    Wu, Bing; Xu, WenXia; Ge, Jun

    This study is a productivity review on the literature gleaned from SSCI, SCIE databases concerning innovation research in E-Learning. The result indicates that the number of literature productions on innovation research in ELearning is still growing from 2005. The main research development country is England, and from the analysis of the publication year, the number of papers is increasing peaking in 25% of the total in 2010. Meanwhile the main source title is British Journal of Educational Technology. In addition the subject area concentrated on Education & Educational Research, Computer Science, Interdisciplinary Applications and Computer Science, Software Engineering. Moreover the research focuses on are mainly conceptual research and empirical research, which were used to explore E-Learning in respective of innovation diffusion theory, also the limitations and future research of these research were discussed for further research.


    Vasiliy M. Trembatch


    Full Text Available The article covers key stages of e-learning systems development. We try and describe reasons for introduction of intellectual education systems, content of modern intellectual techniques. We also present perspectives for development of intellectual education systems using repeatedly employed components (the typical technical solutions. We present the design of an intellectual education system. Demo-examples are offered as well. 

  11. Theoretical Backgrounds of E-Learning

    Bognar, Branko


    E-learning could be carried out with any theory of learning by applying electronic devices. Skinner, for example, introduced programmed instructions in the 50’s by the aid of mechanical devices that made immediate reinforcement for the right answer possible. In the frame of cognitivism, students could use a computer as a device for experimenting and researching by using multimedia hypertexts. The question about meaning of learning and getting to know not only external reality, but also inner ...

  12. Maths: from distance to e-learning

    David Álvarez Jiménez


    Full Text Available New technological progress and especially the use of Internet have implied a new paradigm on education, and nowadays one of its most prominent features is the rise of a new approach based on an instruction beyond the solid walls of schools and characterized by mobility. That is, e-learning. However, its origins and concept can be traced in time. This paper, focused on mathematics, deals with its evolution, antecedents and present status.

  13. A map of e-Learning

    Botturi, Luca; Tagliatesta, Beatrice


    Goal of the paper is to provide a map of e-learning, in order to help understanding the great complexity of situations hidden under this new and trendy term. Education environments are analyzed according to four main directions: learning models, didactic relationships, activities and technology pervasiveness. The analysis reveals that many apparently new ideas do not depend strictly on new media: new technologies act as a catalyst for a critical re-thinking of teaching and learning.




    Full Text Available This scientific work is presenting the ways to do computer assisted education for students, giving the good practice examples, presenting new electronic learning systems, the advantages and limits and to try to emphasize that these days E-learning is one of the most efficient way to reach education at all levels, specially higher education systems. The objectives of this paper are: to explain the contribution of modern technologies and electronic systems to educational processes, to define the concept of technology based learning, to introduce the electronic tools for education, to present good practice examples in implementing E-learning systems in higher education and corporate environment in Romania and last but not least the new electronic learning systems. Introducing the computers and ITC in educational processes facilitates them and makes the educational system modern and efficient. E - learning innovations offers a core group of professional development courses designed to help anyone achieve professional advancement and personal enrichment. The programs are founded on an extensive experience and understanding of technology-based learning environments. They focus on the most current industry practices for various learning environments and best approaches for multiple learning styles. They ensure that the students get the information and skills needed to achieve more in teaching practice and to confidently enter the distance or online classroom.

  15. 基于流量相关性和数据融合的P2Pbotnet检测%P2P botnet detection based on correlation of flow and information fusion theory

    宋元章; 陈媛; 王安邦


    提出了一种基于网络流量相关性和数据融合理论的实时检测P2P botnet方法,该方法主要关注P2P botnet的命令与控制机制(C&C)机制产生的本质流量---UDP流,它不会受P2P botnet的网络结构、协议和攻击类型的影响。首先分别用自相似性和信息熵来刻画UDP流的相关性特征,利用非参数CUSUM (cumula-tive sum )算法检测上述特征的变化以得到检测结果,然后利用Dempster-Shafer证据理论融合上述特征的检测结果。同时,采用TCP流量特征在一定程度上消除P2P应用程序对P2P botnet检测的影响。实验表明所提出的方法可有效检测新型P2P botnet 。%A real-time detection method-based on correlation of flow and information fusion theory was proposed .It focused on UDP (user datagram protocol) flow ,which was used to build the com-mand and control mechanism of P2P (peer-to-peer) botnet .So the abnormalities of UDP flow are the essential abnormalities of P2P botnet ,which will not change with structures of P2P network ,P2P protocols and attacks .The correlation features of UDP flow was described accurately with the self-similarity and the entropy theory .Two detection results were got separately by disposing abnormali-ties of the above features with the nonparametric CUSUM (cumulative sum) algorithm ,and the final decision detection result was achieved by fusing the above detection results with the Dempster-Shafer evidence theory .Considering that the traffic flow of web applications was likely to affect the detection result ,the features of TCP (transmission control protocol) flow were used to solve the problem .The experiments show that the proposed method can detect P2P botnet with a relatively lower false nega-tive and false positive rate .

  16. Quick Search for Data in Cloud Based on P2P%基于P2P的云中数据的快速搜索

    朱玉平; 刘方爱; 丁鼎; 李倩倩


    Along with the development of cloud computing,data and computing is no longer applications on the desktop and they are used as a service from the cloud. Data as a service makes it possible to access a wealth of distributed and heterogeneous data sources in the cloud. It describes the Dservices, which is a P2P-based query and data operations that can be deployed in the cloud. This system is based on data federal services and adopts dynamic query execution engine which contains data query infrastructure that dynamically adapts to network and node conditions,and the query processing is capable of fully benefiting from all the distributed resources to minimize the query response time and maximize system throughput. Finally,execute simulation shows that Dservices is efficient.%随着云计算的发展,数据和计算不再只是应用在桌面上,而是作为来自云端的一种服务.数据作为一种服务,使得访问云中大量多样的分布式数据资源成为一种可能.文中介绍了DServices,它是一种部署在云中基于P2P查询和数据操作的架构.在查询过程中,该架构基于数据联邦服务,采用动态查询引擎,这种引擎包含了可以适应动态网络和节点状况的数据查询基础设施,同时所有的分布式资源可以有效地支持这个查询处理过程.使用户的查询响应时间大幅减少,同时增加了系统的吞吐量.最后仿真实验表明,DServices是有效的.

  17. P2P Organization Model for Service Clustering Based on Semantic Tree%语义聚集的P2P服务组织模型



    Aiming at solving problems existing in centralized and traditional distributed service discovery mechanism, a new service organization model was proposed. It identifies service by semantic string that comes from a semantic tree based on services functions in the service system. With an improved algorithm based on Kademlia, the model organizes all the services to form a P2P overlay network in which nodes are gathered together according to the semantic tree and can be found using semantic strings. This model has solved the single point failure and bottleneck problem, can find and invoke service without service registry. It is highly scalable, and supports more high-level applications such as dynamic scheduling, fuzzy search. The approach has been successfully applied in a service computing platform,which has already been verified and well operating nearly a year.%针对集中式和传统分布式服务注册与发现机制中存在的问题,提出一种新的服务组织模型.该模型归纳服务系统中各服务功能来建立语义树,依据此语义树产生的语义串对服务进行标识,采用改进的Kademlia算法将服务组织起来,形成按语义树聚集的、使用语义串进行结点发现的P2P覆盖网络,从而解决了单点失效、性能瓶颈问题,实现了不依赖注册中心和注册操作的、自发现的服务调用.它具有高可扩展性,能够支撑动态调度、模糊搜索等应用形式,已在某服务计算平台中成功应用,该平台已通过验收并连续运行近一年.

  18. Recommendations for e-learning in New Product Development teams

    Rutjens, Marjo; Bitter-Rijpkema, Marlies; Pannekeet, Kees


    Rutjens, M., Bitter-Rijpkema, M., & Pannekeet, K. (2009). Recommendations for e-learning in New Product Development teams. Presentation at the e-Learning Baltics conference. June, 16-19, 2009, Rostock, Germany.

  19. Evaluating Usability of E-Learning Systems in Universities

    Nicholas Kipkurui Kiget; Professor G. Wanyembi; Anselemo Ikoha Peters


    The use of e-learning systems has increased significantly in the recent times. E-learning systems are supplementing teaching and learning in universities globally. Kenyan universities have adopted e-learning technologies as means for delivering course content. However despite adoption of these systems, there are considerable challenges facing the usability of the systems. Lecturers and students have different perceptions in regard to the usability of e-learning systems. The aim of this study ...

  20. e-Learning for Lifelong Learning in Denmark

    Buhl, Mie; Andreasen, Lars Birch


    The chapter on 'e-Learning for Lifelong Learning in Denmark' is part of an international White Paper, focusing on educational systems, describing status and characteristics and highlighting specific cases of e-learning and of lifelong learning.......The chapter on 'e-Learning for Lifelong Learning in Denmark' is part of an international White Paper, focusing on educational systems, describing status and characteristics and highlighting specific cases of e-learning and of lifelong learning....