WorldWideScience

Sample records for hybrid peer-to-peer networks

  1. Peer to Peer Network Mergence

    Institute of Scientific and Technical Information of China (English)

    ZHANGYunfei; CHENChangjia

    2005-01-01

    We propose the conception and infrastructure of peer-to-peer network mergence. We show that Peer to peer (P2P for short) mergence is possible and advantageous in file sharing, balance of scalability and performance, higher searching efficiency and security. We alsoput forward four possible mergence schemes-bigger chord,gateway chord, overlay chord and line chord and compare their performance. We find that overlay chord could achieve the same performance as that of bigger chord. Finally one practical solution is proposed to illustrate our idea.

  2. Peer to Peer Networks Management Survey

    CERN Document Server

    Amad, Mourad; Aïssani, Djamil

    2012-01-01

    Peer-to-Peer systems are based on the concept of resources localization and mutualisation in dynamic context. In specific environment such as mobile networks, characterized by high variability and dynamicity of network conditions and performances, where nodes can join and leave the network dynamically, resources reliability and availability constitute a critical issue. The resource discovery problem arises in the context of peer to peer (P2P) networks, where at any point of time a peer may be placed at or removed from any location over a general purpose network. Locating a resource or service efficiently is one of the most important issues related to peer-to-peer networks. The objective of a search mechanism is to successfully locate resources while incurring low overhead and low delay. This paper presents a survey on P2P networks management: classification, applications, platforms, simulators and security.

  3. A robust cluster-based dynamic-super-node scheme for hybrid peer-to-peer network

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Hybrid peer-to-peer (P2P) system can improve the performance of the entire system using super-peer. But it is difficult to measure a peer's capability exactly and ensure high reliability of the network. This paper proposes a scheme to solve these problems. Firstly, we present a hybrid P2P network in which the upper layer is Chord network and the lower layer is cluster. Then we provide a strategy to measure a peer's capability so that a cluster can be organized to be a sorting network in which peers are classified into three types: dynamic-super-node (DSN), backup-node (BN) and ordinary-node (ON). In a cluster, DSN and BNs are strongly connected. And based on this, we present an algorithm DSN flood min (DSNFM) to select DSN BN and maintain consensus of the cluster. Furthermore, we do a reliability analysis of the cluster based on churn rate of the network and gathered three rules of thumb from our simulations.

  4. Multiple description coding with spatial-temporal hybrid interpolation for video streaming in peer-to-peer networks

    Institute of Scientific and Technical Information of China (English)

    LU Meng-ting; LIN Chang-kuan; YAO Jason; CHEN Homer H.

    2006-01-01

    In this paper, we present an innovative design of multiple description coding with spatial-temporal hybrid interpolation (MDC-STHI) for peer-to-peer (P2P) video streaming. MDC can be effective in P2P networks because the nature of overlay routing makes path diversity more feasible. However, most MDC schemes require a redesign of video coding systems and are not cost-effective for wide deployment. We base our work on multiple state video coding, a form of MDC that can utilize standard codecs. Two quarter-sized video bit streams are generated as redundancies and embedded in the original-sized streams. With MDC-STHI, the nodes in P2P network can adjust the streaming traffic to satisfy the constraints of their devices and network environment. By design, the redundancies are used to compensate for missing frames, and can also be streamed independently to fulfill certain needs of low rate, low resolution applications. For better error concealment, optimal weights for spatial and temporal interpolation are determined at the source, quantized, and included in redundancies.

  5. Jupiter: Peer-to-Peer Networking Platform over Heterogeneous Networks

    Directory of Open Access Journals (Sweden)

    Norihiro Ishikawa

    2006-10-01

    Full Text Available Peer-to-peer has entered the public limelight over the last few years. Several research projects are underway on peer-to-peer technologies, but no definitive conclusion is currently available. Compared with traditional Internet technologies, peer-to-peer has the potential to realize highly scalable, extensible, and efficient distributed applications. This is because its basic functions realize resource discovery, resource sharing, and load balancing in a highly distributed manner. An easy prediction is the emergence of an environment in which many sensors, people, and many different kinds of objects exist, move, and communicate with one another. Peer-to-peer is one of the most important and suitable technologies for such networking since it supports discovery mechanisms, simple one-to-one communication between devices, free and extensible distribution of resources, and distributed search to handle the enormous number of resources. The purpose of this study is to explore a universal peer-to-peer network architecture that will allow various devices to communicate with one another across various networks. We have been designing architecture and protocols for realizing peer-to-peer networking among various devices. We are currently designing APIs that are available for various peer-to-peer applications and are implementing a prototype called "Jupiter" as a peer-to-peer networking platform over heterogeneous networks.

  6. Child Pornography in Peer-to-Peer Networks

    Science.gov (United States)

    Steel, Chad M. S.

    2009-01-01

    Objective: The presence of child pornography in peer-to-peer networks is not disputed, but there has been little effort done to quantify and analyze the distribution and nature of that content to-date. By performing an analysis of queries and query hits on the largest peer-to-peer network, we are able to both quantify and describe the nature of…

  7. Distributed Data Mining in Peer-to-Peer Networks

    Data.gov (United States)

    National Aeronautics and Space Administration — Peer-to-peer (P2P) networks are gaining popularity in many applications such as file sharing, e-commerce, and social networking, many of which deal with rich,...

  8. Scalable peer-to-peer resource discovering scheme for wireless self-organized networks

    Institute of Scientific and Technical Information of China (English)

    LI Xi; JI Hong

    2009-01-01

    Peer-to-peer technologies have attracted increasing research attention with fruitful protocols and applications proposed for wired networks. As to mobile environments, there are currently no mature deployments. A novel resource managing and discovering protocol, Cheer, is proposed to realize scalable and effective peer-to-peer lookup in wireless self-organized networks. Cheer resolves the topologies mismatch problem between peer-to-peer overlay networks and actual nodes distribution, allowing for frequent nodes membership changes. With specially designed resource storage table, Cheer also supports multikey and fuzzy lookup. Its hybrid architecture and improved routing scheme based on small-world theory may realize effective lookup routing. Theoretical analysis and simulation results both prove that Cheer makes using peer-to-peer applications in large-scale self-organized mobile networks feasible and promising.

  9. Peer to peer networking in Ethernet broadband access networks

    OpenAIRE

    Damola, Ayodele

    2005-01-01

    The use of peer-to-peer (P2P) applications is growing dramatically, particularly for sharing content such as video, audio, and software. The traffic generated by these applications represents a large proportion of Internet traffic. For the broadband access network providers P2P traffic presents several problems. This thesis identifies the performance and business issues that P2P traffic has on broadband access networks employing the McCircuit separation technique. A mechanism for managing P2P...

  10. Collaborative work model based on peer-to-peer network

    Institute of Scientific and Technical Information of China (English)

    JIANG Jian-zhong; FU Li; ZHANG Xuan-peng; XU Chuan-yun

    2007-01-01

    In this paper, we incorporated peer-to-peer (P2P) concept with agent technology and put forward a collaborative work model based on peer-to-peer network (P2PCWM) after investigating into business demands of modern enterprises and problems prevailing in mainstream collaborative work systems based on central server. Theoretically, the P2PCWM can effectively overcome the problems in a conventional system with a central server and meet the practical demands of modern businesses. It is distinguished from other systems by its features of equality, openness, promptness, fairness, expandability and convenience.

  11. PLATON: Peer-to-Peer load adjusting tree overlay networks

    NARCIS (Netherlands)

    Lymberopoulos, L.; Pittaras, C.; Grammatikou, M.; Papavassiliou, S.; Maglaris, V.

    2011-01-01

    Peer-to-Peer systems supporting multi attribute and range queries use a number of techniques to partition the multi dimensional data space among participating peers. Load-balancing of data accross peer partitions is necessary in order to avoid the presence of network hotspots which may cause

  12. PLATON: Peer-to-Peer load adjusting tree overlay networks

    NARCIS (Netherlands)

    Lymberopoulos, L.; Pittaras, C.; Grammatikou, M.; Papavassiliou, S.; Maglaris, V.

    2011-01-01

    Peer-to-Peer systems supporting multi attribute and range queries use a number of techniques to partition the multi dimensional data space among participating peers. Load-balancing of data accross peer partitions is necessary in order to avoid the presence of network hotspots which may cause perform

  13. Security properties in an open peer-to-peer network

    CERN Document Server

    Lalande, Jean-Francois; Toinard, Christian

    2010-01-01

    This paper proposes to address new requirements of confidentiality, integrity and availability properties fitting to peer-to-peer domains of resources. The enforcement of security properties in an open peer-topeer network remains an open problem as the literature have mainly proposed contribution on availability of resources and anonymity of users. That paper proposes a novel architecture that eases the administration of a peer-to-peer network. It considers a network of safe peer-to-peer clients in the sense that it is a commune client software that is shared by all the participants to cope with the sharing of various resources associated with different security requirements. However, our proposal deals with possible malicious peers that attempt to compromise the requested security properties. Despite the safety of an open peer-to-peer network cannot be formally guaranteed, since a end user has privileges on the target host, our solution provides several advanced security enforcement. First, it enables to for...

  14. Stature System Protocols for Peer to Peer Networks: A Survey

    OpenAIRE

    Ankita Thadani; Vinit Gupta; IndraJeet Rajput

    2014-01-01

    There are various websites presently used by us so the situation arises where people transact with unknown agents and take decision for these agents for by considering the stature score. Central idea of this paper is to compare online stature reporting systems that are particularly suitable for the peer to peer network but uses different approaches for calculating the stature of an entity. This paper describes the working of these stature systems, their properties and various parameters advan...

  15. Stability analysis of peer-to-peer networks against churn

    Indian Academy of Sciences (India)

    Bivas Mitra; Sujoy Ghose; Niloy Ganguly; Fernando Peruani

    2008-08-01

    Users of the peer-to-peer system join and leave the network randomly, which makes the overlay network dynamic and unstable in nature. In this paper, we propose an analytical framework to assess the robustness of p2p networks in the face of user churn. We model the peer churn through degree-independent as well as degree-dependent node failure. Lately, superpeer networks are becoming the most widely used topology among the p2p networks. Therefore, we perform the stability analysis of superpeer networks as a case study. We validate the analytically derived results with the help of simulation.

  16. Universal Peer-to-Peer Network Investigation Framework

    OpenAIRE

    Scanlon, Mark; Kechadi, Tahar

    2013-01-01

    Peer-to-Peer (P2P) networking has fast become a useful technological advancement for a vast range of cyber criminal activities. Cyber crimes from copyright infringement and spamming, to serious, high financial impact crimes, such as fraud, distributed denial of service attacks (DDoS) and phishing can all be aided by applications and systems based on the technology. The requirement for investigating P2P based systems is not limited to the more well known cyber crimes listed above, as many more...

  17. Intellectual Property Rights Protection in Peer to Peer Networks

    Science.gov (United States)

    Stylios, Georgios; Tsolis, Dimitrios

    Peer to Peer Networks are oftenly used by internet users to share and distribute digital content (images, audio and video) which is in most of cases protected by the Intellectual Property Rights (IPR) legislation. This fact threatens e-inclusion and Internet democracy as a whole as it forces organizations to block access to valuable content. This paper claims that IPR protection and P2P can be complementary. Specifically, a P2P infrastructure is presented which allows broad digital content exchange while on the same time supports data and copyright protection through watermarking technologies.

  18. Key agreement in peer-to-peer wireless networks

    DEFF Research Database (Denmark)

    Cagalj, Mario; Capkun, Srdjan; Hubaux, Jean-Pierre

    2006-01-01

    We present a set of simple techniques for key establishment over a radio link in peer-to-peer networks. Our approach is based on the Diffie-Hellman key agreement protocol, which is known to be vulnerable to the “man-in-the-middle” attack if the two users involved in the protocol do not share any......: the first is based on visual comparison of short strings, the second on distance bounding, and the third on integrity codes; in each case, the users do not need to enter any password or other data, nor do they need physical or infrared connectivity between their devices. We base our analysis on a well...

  19. STATURE SYSTEM PROTOCOLS FOR PEER TO PEER NETWORKS: A SURVEY

    Directory of Open Access Journals (Sweden)

    Ankita Thadani

    2015-10-01

    Full Text Available There are various websites presently used by us so the situation arises where people transact with unknown agents and take decision for these agents for by considering the stature score. Central idea of this paper is to compare online stature reporting systems that are particularly suitable for the peer to peer network but uses different approaches for calculating the stature of an entity. This paper describes the working of these stature systems, their properties and various parameters advantages and disadvantages. Finally, it concludes by comparison of all these stature system protocols.

  20. Stature System Protocols for Peer to Peer Networks: A Survey

    Directory of Open Access Journals (Sweden)

    Ankita Thadani

    2014-12-01

    Full Text Available There are various websites presently used by us so the situation arises where people transact with unknown agents and take decision for these agents for by considering the stature score. Central idea of this paper is to compare online stature reporting systems that are particularly suitable for the peer to peer network but uses different approaches for calculating the stature of an entity. This paper describes the working of these stature systems, their properties and various parameters advantages and disadvantages. Finally, it concludes by comparison of all these stature system protocols.

  1. A Threshold Scheme under Peer-to-Peer Network

    Institute of Scientific and Technical Information of China (English)

    XIE Yumin; SHI Feng; MING Yang; MUHAMMAD Kamran; XU Jianqiang

    2006-01-01

    Resource sharing among peers is one of important application in Peer-to-Peer(P2P) network. Inexistence of server makes P2P network to be a less trustable tool for property owners to distribute their resource. In order to protect intelligent property, reputation management strategy is adopted in many P2P network. As long as a P2P network reputation strategy is confirmed, application designer can employ a special detailed distribution scheme to fulfill content distribution within the net. Shmir (k,n) threshold scheme, for example, is an encryption scheme to enhance the distribution security of this kind of design. (k*,n) threshold scheme is a new tool similar to Shmir scheme is proposed in this paper. The new scheme based on polynomial expansion and its security is decided by the one way function used in the secret distribution procedure. The scheme efficiency and its features as well as comparison between new and Shmir scheme are also discussed in this paper.

  2. Peer-to-Peer Enclaves for Improving Network Defence

    Directory of Open Access Journals (Sweden)

    David W. Archer

    2013-07-01

    Full Text Available Information about cyberthreats within networks spreads slowly relative to the speed at which those threats spread. Typical "threat feeds" that are commercially available also disseminate information slowly relative to the propagation speed of attacks, and they often convey irrelevant information about imminent threats. As a result, hosts sharing a network may miss opportunities to improve their defence postures against imminent attack because needed information arrives too late or is lost in irrelevant noise. We envision timely, relevant peer-to-peer sharing of threat information – based on current technologies – as a solution to these problems and as a useful design pattern for defensive cyberwarfare. In our setting, network nodes form communities that we call enclaves, where each node defends itself while sharing information on imminent threats with peers that have similar threat exposure. In this article, we present our vision for this solution. We sketch the architecture of a typical node in such a network and how it might interact with a framework for sharing threat information; we explain why certain defensive countermeasures may work better in our setting; we discuss current tools that could be used as components in our vision; and we describe opportunities for future research and development.

  3. Innovative Rated-Resource Peer-to-Peer Network

    CERN Document Server

    Sharma, Abhishek; 10.5121/ijcnc.2010.2206

    2010-01-01

    Peer-to-Peer (P2P) networks provide a significant solution for file sharing among peers connected to Internet. It is fast and completely decentralised system with robustness. But due to absence of a server documents on a P2P network are not rated which makes it difficult for a peer to obtain precise information in result of a query. In past, some researchers tried to attach ratings to the peers itself but it was complex and less effective. In this paper, a novel P2P architecture is proposed which attaches ratings to the uploaded document directly. These ratings then become as element in its XML advertisement which has several child elements for information classification. The attached element is extracted from the advertisement in real time and the document is then sorted accordingly. Therefore, the information can be easily sorted based on a request by a peer according to the relevance of matter. The information regarding relevance is obtained by the peer issuing the query. This research leads to a smart P...

  4. Research on Intellectual Property Right Problems of Peer-to-Peer Networks.

    Science.gov (United States)

    Dong, Ying; Li, Mingshu; Chen, Meizhang; Zheng, Shengli

    2002-01-01

    Discusses digital intellectual property rights relating to peer-to-peer networks, using Napster as an example. Suggests anti-piracy solutions to prevent litigation and considers how libraries can develop potential service models using peer-to-peer networks, including the development of personal libraries on the Internet, interlibrary loan,…

  5. Research on Intellectual Property Right Problems of Peer-to-Peer Networks.

    Science.gov (United States)

    Dong, Ying; Li, Mingshu; Chen, Meizhang; Zheng, Shengli

    2002-01-01

    Discusses digital intellectual property rights relating to peer-to-peer networks, using Napster as an example. Suggests anti-piracy solutions to prevent litigation and considers how libraries can develop potential service models using peer-to-peer networks, including the development of personal libraries on the Internet, interlibrary loan,…

  6. Secure Peer-to-Peer Networks for Scientific Information Sharing

    Science.gov (United States)

    Karimabadi, Homa

    2012-01-01

    The most common means of remote scientific collaboration today includes the trio of e-mail for electronic communication, FTP for file sharing, and personalized Web sites for dissemination of papers and research results. With the growth of broadband Internet, there has been a desire to share large files (movies, files, scientific data files) over the Internet. Email has limits on the size of files that can be attached and transmitted. FTP is often used to share large files, but this requires the user to set up an FTP site for which it is hard to set group privileges, it is not straightforward for everyone, and the content is not searchable. Peer-to-peer technology (P2P), which has been overwhelmingly successful in popular content distribution, is the basis for development of a scientific collaboratory called Scientific Peer Network (SciPerNet). This technology combines social networking with P2P file sharing. SciPerNet will be a standalone application, written in Java and Swing, thus insuring portability to a number of different platforms. Some of the features include user authentication, search capability, seamless integration with a data center, the ability to create groups and social networks, and on-line chat. In contrast to P2P networks such as Gnutella, Bit Torrent, and others, SciPerNet incorporates three design elements that are critical to application of P2P for scientific purposes: User authentication, Data integrity validation, Reliable searching SciPerNet also provides a complementary solution to virtual observatories by enabling distributed collaboration and sharing of downloaded and/or processed data among scientists. This will, in turn, increase scientific returns from NASA missions. As such, SciPerNet can serve a two-fold purpose for NASA: a cost-savings software as well as a productivity tool for scientists working with data from NASA missions.

  7. Mitigating Free Riding in Peer-To-Peer Networks: Game Theory ...

    African Journals Online (AJOL)

    Mitigating Free Riding in Peer-To-Peer Networks: Game Theory Approach. ... Through extensive simulations, we show that this mechanism can increase fairness and encourage resource contribution by peers to the network. ... Article Metrics.

  8. A Database Query Processing Model in Peer-To-Peer Network ...

    African Journals Online (AJOL)

    PROMOTING ACCESS TO AFRICAN RESEARCH ... This paper presents an extensive evaluation of database query processing model in peer-to-peer networks using top-k query processing technique and implemented by Java,and MySql.

  9. Super-proximity routing in structured peer-to-peer overlay networks

    Institute of Scientific and Technical Information of China (English)

    吴增德; 饶卫雄; 马范援

    2004-01-01

    Peer-to-Peer systems are emerging as one of the most popular Intemet applications. Structured Peer-to-Peer overlay networks use identifier based routing algorithms to allow robustness, load balancing, and distributed lookup needed in this environment. However, identifier based routing that is independent of Internet topology tends to be of low efficiency. Aimed at improving the routing efficiency, the super-proximity routing algorithms presented in this paper combine Internet topology and over|ay routing table in choosing the next hop. Experimental results showed that the algorithms greatly improve the efficiency of Peer-to-Peer routing.

  10. Super-proximity routing in structured peer-to-peer overlay networks

    Institute of Scientific and Technical Information of China (English)

    WU Zeng-de(吴增德); RAO Wei-xiong(饶卫雄); MA Fan-yuan(马范援)

    2004-01-01

    Peer-to-Peer systems are emerging as one of the most popular Internet applications. Structured Peer-to-Peer overlay networks use identifier based routing algorithms to allow robustness, load balancing, and distributed lookup needed in this environment. However, identifier based routing that is independent of Internet topology tends to be of low efficiency. Aimed at improving the routing efficiency, the super-proximity routing algorithms presented in this paper combine Internet topology and overlay routing table in choosing the next hop. Experimental results showed that the algorithms greatly improve the efficiency of Peer-to-Peer routing.

  11. Hybrid Peer-to-peer Streaming System for Mobile Peers with Transcoding

    Directory of Open Access Journals (Sweden)

    Shuai Zeng

    2015-08-01

    Full Text Available In this paper, we study in hybrid peer-to-peer (P2P streaming system, which includes fixed peers and mobile peers in the same network, and propose a flow rate allocation algorithm to optimize the streaming system. In the proposed algorithm, based on transcoding technique, we describe how to exchange original and transcoded data among video source server, fixed and mobile peers. The purpose of our algorithm is to reduce the bandwidth demand of video source server, while ensuring the flow rate of video data sending to any peer no less than its video coding rate. We compare the performance of P2P streaming system using our algorithm with traditional design in various situations in the simulation experiment, and test how much benefit the system can get from the new algorithm. The results show that, if the flow rate of video data is allocated appropriately, better performance of streaming system can be achieved.

  12. FFT-based Network Coding For Peer-To-Peer Content Delivery

    CERN Document Server

    Soro, Alexandre

    2009-01-01

    In this paper, we propose a structured peer-to-peer (P2P) distribution scheme based on Fast Fourier Transform (FFT) graphs. We build a peer-to-peer network that reproduces the FFT graph initially designed for hardware FFT codecs. This topology allows content delivery with a maximum diversity level for a minimum global complexity. The resulting FFTbased network is a structured architecture with an adapted network coding that brings flexibility upon content distribution and robustness upon the dynamic nature of the network. This structure can achieve optimal capacity in terms of content recovery while solving the problem of last remaining blocks, even for large networks.

  13. EZEL : a Visual Tool for Performance Assessment of Peer-to-Peer File-Sharing Networks

    NARCIS (Netherlands)

    Voinea, Lucian; Telea, Alex; Wijk, Jarke J. van

    2004-01-01

    In this paper we present EZEL, a visual tool we developed for the performance assessment of peer-to-peer file-sharing networks. We start by identifying the relevant data transferred in this kind of networks and the main performance assessment questions. Then we describe the visualization of data fro

  14. A peer-to-peer file search and download protocol for wireless ad-hoc networks

    NARCIS (Netherlands)

    Sözer, H.; Tekkalmaz, M.; Korpeoglu, I.

    2009-01-01

    Deployment of traditional peer-to-peer file sharing systems on a wireless ad-hoc network introduces several challenges. Information and workload distribution as well as routing are major problems for members of a wireless ad-hoc network, which are only aware of their immediate neighborhood. In this

  15. Information Propagation in Peer-to-Peer Networking: Modeling and Empirical Studies

    NARCIS (Netherlands)

    Tang, S.

    2010-01-01

    Although being a young technology, peer-to-peer (P2P) networking has spurred dramatic evolution on the Internet over the recent twenty years. Unlike traditional server-client mode, P2P networking applications are user-centric. Users (peers) generate their own content and share it with others across

  16. Information Propagation in Peer-to-Peer Networking: Modeling and Empirical Studies

    NARCIS (Netherlands)

    Tang, S.

    2010-01-01

    Although being a young technology, peer-to-peer (P2P) networking has spurred dramatic evolution on the Internet over the recent twenty years. Unlike traditional server-client mode, P2P networking applications are user-centric. Users (peers) generate their own content and share it with others across

  17. A Local Scalable Distributed Expectation Maximization Algorithm for Large Peer-to-Peer Networks

    Science.gov (United States)

    Bhaduri, Kanishka; Srivastava, Ashok N.

    2009-01-01

    This paper offers a local distributed algorithm for expectation maximization in large peer-to-peer environments. The algorithm can be used for a variety of well-known data mining tasks in a distributed environment such as clustering, anomaly detection, target tracking to name a few. This technology is crucial for many emerging peer-to-peer applications for bioinformatics, astronomy, social networking, sensor networks and web mining. Centralizing all or some of the data for building global models is impractical in such peer-to-peer environments because of the large number of data sources, the asynchronous nature of the peer-to-peer networks, and dynamic nature of the data/network. The distributed algorithm we have developed in this paper is provably-correct i.e. it converges to the same result compared to a similar centralized algorithm and can automatically adapt to changes to the data and the network. We show that the communication overhead of the algorithm is very low due to its local nature. This monitoring algorithm is then used as a feedback loop to sample data from the network and rebuild the model when it is outdated. We present thorough experimental results to verify our theoretical claims.

  18. Managing Peer to Peer and Overlay Content Traffic in ISP Networks

    Directory of Open Access Journals (Sweden)

    Stanislaus Kaosoluchukwu Ogbuokebe

    2013-04-01

    Full Text Available Peer-to-Peer content distribution systems are major source of traffic in today’s internet services, Peer-to-peer (P2P traffic consumes network resources without creating additional revenue. It is estimated that high percentage of broadband bandwidth is consumed by downloads of music, games, video, and other content. The use of peer to peer systems introduces many new problems related to traffic engineering or network optimization. This research work will investigate characteristics and behavioural interactions between Peer to Peer overlay content distribution operations, as well as suggests/discuss algorithms for optimizing P2P content distribution overlay infrastructure and the internet service provider “ISP” network. Techniques to harmonise the relationship between P2P overlay content distribution services and the underlying network is also discussed. Indeed the system performance of a P2P network is critically affected by its overload, thus the processing load of the peers, the communication load and the system management load, must be carefully handled to obtain satisfactory system performance.

  19. mitigating mitigating free riding in peer-to-peer networks

    African Journals Online (AJOL)

    eobe

    network variety, disk space used, bandwidth, altruism and financial transfer. With the ... that Nash equilibrium is hard to compute and does not capture the highly .... classified based on different criteria such as structure, degree of centralization ...

  20. An initial peer configuration algorithm for multi-streaming peer-to-peer networks

    CERN Document Server

    Ishii, Tomoyuki

    2012-01-01

    The growth of the Internet technology enables us to use network applications for streaming audio and video. Especially, real-time streaming services using peer-to-peer (P2P) technology are currently emerging. An important issue on P2P streaming is how to construct a logical network (overlay network) on a physical network (IP network). In this paper, we propose an initial peer configuration algorithm for a multi-streaming peer-to-peer network. The proposed algorithm is based on a mesh-pull approach where any node has multiple parent and child nodes as neighboring nodes, and content transmitted between these neighboring nodes depends on their parent-child relationships. Our simulation experiments show that the proposed algorithm improves the number of joining node and traffic load.

  1. Mobile Web Service Discovery in Peer to Peer Networks

    CERN Document Server

    Srirama, Satish Narayana; Prinz, Wolfgang

    2010-01-01

    The advanced features of today's smart phones and hand held devices, like the increased memory and processing capabilities, allowed them to act even as information providers. Thus a smart phone hosting web services is not a fancy anymore. But the relevant discovery of these services provided by the smart phones has became quite complex, because of the volume of services possible with each Mobile Host providing some services. Centralized registries have severe drawbacks in such a scenario and alternate means of service discovery are to be addressed. P2P domain with it resource sharing capabilities comes quite handy and here in this paper we provide an alternate approach to UDDI registry for discovering mobile web services. The services are published into the P2P network as JXTA modules and the discovery issues of these module advertisements are addressed. The approach also provides alternate means of identifying the Mobile Host.

  2. Analysis on the performance dependency of channel models in a wireless peer-to-peer network

    Science.gov (United States)

    Wang, Yupeng; Liu, Tianlong; Yu, Zelong; Li, Yufeng

    2017-08-01

    In order to reduce the simulation complexity and time of peer-to-peer network such as Ad Hoc network, most simulations only use the simplified Free Space Model or Two Ray Ground model to approximate the attenuation due to the wireless transmission without considering the dependency between system performance and channel models. In this paper, the effects of channel models on the wireless peer-to-peer network performance is analyzed in more details by using the conventional routing and medium access control algorithm to find the system performance sensitivity to different channel models. Through the computer simulation using network simulator 2, we found that some aspects of the system performance is only sensitive to the large scale fading effects, while others are not.

  3. Peer-to-Peer Video Conferencing Using Hybrid Content Distribution Model

    Directory of Open Access Journals (Sweden)

    Imad Jasim

    2012-01-01

    Full Text Available Problem statement: Multimedia Conferencing System (MCS is a server-based video conferencing system. One of the most critical limitations faced by this approach is the scalability issue. In the MCS, the outgoing bandwidth of the server is shared among all concurrent clients. Thus, the more clients there are, the lesser the bandwidth each client can have. The performance of this approach therefore deteriorates rapidly as the number of simultaneous clients increases. In addition, a pure server-based solution is expensive. Approach: In this research, the server-based infrastructure is modified into a peer-to-peer video conferencing system while preserving the same functionality and features of the existing MCS. This modification can be achieved using a hybrid content distribution model, which is a combination of fluid and chunk content distribution models to distribute parts of the video stream fairly among participants. The hybrid content distribution model offers a better way of handling heterogeneous networks because it can distinguish between a fast peer and a slow peer, dealing with each one according to its capabilities. Results: In our proposed system, the function server will not be used for video distribution. Instead, it will only be used for monitoring and controlling the peers to reduce the burden on the servers. Experimental results conducted in the nation advanced IPv6 center as a real environment and live conferencing. Conclusion: This will lead to overcome the problem of scalability and a bandwidth bottleneck on the main server and achieve good way to distribute video chunks.

  4. Peer-to-Peer Overlay in Mobile Ad-hoc Networks

    Science.gov (United States)

    Castro, Marcel C.; Kassler, Andreas J.; Chiasserini, Carla-Fabiana; Casetti, Claudio; Korpeoglu, Ibrahim

    Wireless multi-hop networks such as mobile ad-hoc (MANET) or wireless mesh networks (WMN) have attracted big research efforts during the last years as they have huge potential in several areas such as military communications, fast infrastructure replacement during emergency operations, extension of hotspots or as an alternative communication system. Due to various reasons, such as characteristics of wireless links, multi-hop forwarding operation, and mobility of nodes, performance of traditional peer-to-peer applications is rather low in such networks. In this book chapter, we provide a comprehensive and in-depth survey on recent research on various approaches to provide peer-to-peer services in wireless multi-hop networks. The causes and problems for low performance of traditional approaches are discussed. Various representative alternative approaches to couple interactions between the peer-to-peer overlay and the network layer are examined and compared. Some open questions are discussed to stimulate further research in this area.

  5. Lower Bound on de Bruijn Graphs Out-degree for Lower Traffic Load in Peer-to-peer Networks

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; ZUO Min; PAN Li; LI Jian-hua

    2006-01-01

    Designers search for N-nodes peer-to-peer networks that can have O(1) out-degree with O(log2 N) average distance.Peer-to-peer schemes based on de Bruijn graphs are found to meet this requirement. By defining average load to evaluate the traffic load in a network, we show that in order to decrease the average load, the average distance of a network should decrease while the out-degree should increase.Especially, given out-degree k and N nodes, peer-to-peer schemes based on de Bruijn graphs have lower average load than other existing systems. The out-degree k of de Bruijn graphs should not be O(1) but should satisfy a lower bound described by an inequality kk≥ N2, to ensure that the average load in peer-to-peer schemes based on de Bruijn graphs will not exceed that in Chord system.

  6. An Introduction to Models of Online Peer-to-Peer Social Networking

    CERN Document Server

    Kesidis, George

    2010-01-01

    This book concerns peer-to-peer applications and mechanisms operating on the Internet, particularly those that are not fully automated and involve significant human interaction. So, the realm of interest is the intersection of distributed systems and online social networking. Generally, simple models are described to clarify the ideas. Beginning with short overviews of caching, graph theory and game theory, we cover the basic ideas of structured and unstructured search. We then describe a simple framework for reputations and for iterated referrals and consensus. This framework is applied to a

  7. A "cluster" based search scheme in peer-to-peer network

    Institute of Scientific and Technical Information of China (English)

    李振武; 杨舰; 史旭东; 白英彩

    2003-01-01

    This paper presents a "cluster" based search scheme in peer-to-peer network. The idea is based on the fact that data distribution in an information society has structured feature. We designed an algorithm to cluster peers that have similar interests. When receiving a query request, a peer will preferentially forward it to another peer which belongs to the same cluster and shares more similar interests. By this way search efficiency will be remarkably improved and at the same time good resilience against peer failure (the ability to withstand peer failure) is reserved.

  8. A "cluster" based search scheme in peer-to-peer network

    Institute of Scientific and Technical Information of China (English)

    李振武; 杨舰; 史旭东; 白英彩

    2003-01-01

    This paper presents a "cluster" based search scheme in peer-to-peer network. The idea is based on the fact that data distribution in an information society has structured feature. We designed an algorithm to cluster peers that have similar interests. When receiving a query request, a peer will preferentially forward it to another peer which belongs to the same cluster and shares more similar interests. By this way search efficiency will be remarkably improved and at the same time good resilience against peer failure (the ability to withstand peer failure) is reserved.

  9. Global phenomena from local rules: Peer-to-peer networks and crystal steps

    Science.gov (United States)

    Finkbiner, Amy

    Even simple, deterministic rules can generate interesting behavior in dynamical systems. This dissertation examines some real world systems for which fairly simple, locally defined rules yield useful or interesting properties in the system as a whole. In particular, we study routing in peer-to-peer networks and the motion of crystal steps. Peers can vary by three orders of magnitude in their capacities to process network traffic. This heterogeneity inspires our use of "proportionate load balancing," where each peer provides resources in proportion to its individual capacity. We provide an implementation that employs small, local adjustments to bring the entire network into a global balance. Analytically and through simulations, we demonstrate the effectiveness of proportionate load balancing on two routing methods for de Bruijn graphs, introducing a new "reversed" routing method which performs better than standard forward routing in some cases. The prevalence of peer-to-peer applications prompts companies to locate the hosts participating in these networks. We explore the use of supervised machine learning to identify peer-to-peer hosts, without using application-specific information. We introduce a model for "triples," which exploits information about nearly contemporaneous flows to give a statistical picture of a host's activities. We find that triples, together with measurements of inbound vs. outbound traffic, can capture most of the behavior of peer-to-peer hosts. An understanding of crystal surface evolution is important for the development of modern nanoscale electronic devices. The most commonly studied surface features are steps, which form at low temperatures when the crystal is cut close to a plane of symmetry. Step bunching, when steps arrange into widely separated clusters of tightly packed steps, is one important step phenomenon. We analyze a discrete model for crystal steps, in which the motion of each step depends on the two steps on either side of

  10. Building Trust Peer-to-peer Networks with TLS and X.509 Certificates

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    As soon as a P2P application grows to the point where it becomes interesting, the issues of trust and security appear on the horizon. The core of the paper is on how to build trustful peer-to-peer networks with TLS and X.509 certificates under JXTA architecture. The use of authentication, authorization, and encryption establishes trust in P2P applications. Without a foundation of trust, many types of interesting applications such as e-commerce won't take hold on top of the P2P infrastructure.

  11. An Efficient Causal Group Communication Protocol for Free Scale Peer-to-Peer Networks

    Directory of Open Access Journals (Sweden)

    Grigory Evropeytsev

    2016-08-01

    Full Text Available In peer-to-peer (P2P overlay networks, a group of n (≥2 peer processes have to cooperate with each other. Each peer sends messages to every peer and receives messages from every peer in a group. In group communications, each message sent by a peer is required to be causally delivered to every peer. Most of the protocols designed to ensure causal message order are designed for networks with a plain architecture. These protocols can be adapted to use in free scale and hierarchical topologies; however, the amount of control information is O(n, where n is the number of peers in the system. Some protocols are designed for a free scale or hierarchical networks, but in general they force the whole system to accomplish the same order viewed by a super peer. In this paper, we present a protocol that is specifically designed to work with a free scale peer-to-peer network. By using the information about the network’s architecture and by representing message dependencies on a bit level, the proposed protocol ensures causal message ordering without enforcing super peers order. The designed protocol is simulated and compared with the Immediate Dependency Relation and the Dependency Sequences protocols to show its lower overhead.

  12. Key Exchange Trust Evaluation in Peer-to-Peer Sensor Networks With Unconditionally Secure Key Exchange

    Science.gov (United States)

    Gonzalez, Elias; Kish, Laszlo B.

    2016-03-01

    As the utilization of sensor networks continue to increase, the importance of security becomes more profound. Many industries depend on sensor networks for critical tasks, and a malicious entity can potentially cause catastrophic damage. We propose a new key exchange trust evaluation for peer-to-peer sensor networks, where part of the network has unconditionally secure key exchange. For a given sensor, the higher the portion of channels with unconditionally secure key exchange the higher the trust value. We give a brief introduction to unconditionally secured key exchange concepts and mention current trust measures in sensor networks. We demonstrate the new key exchange trust measure on a hypothetical sensor network using both wired and wireless communication channels.

  13. Topology-aware peer-to-peer overlay network for Ad-hoc

    Institute of Scientific and Technical Information of China (English)

    WANG Shi-guo; JI Hong; LI Ting; MEI Jing-qing

    2009-01-01

    The mismatch between the structured peer-to-peer (P2P) overlay network, which is based on Hashing, and the actual physical network, leads to query repeatedly passing through some nodes in the actual route when it is applied in Ad-hoc networks. An approach of getting an appropriate node identifier (ID) bearing its local physical information is proposed, in which the traditional theory of getting node ID through Hashing the node's Internet protocol (IP) address is abandoned, and a topology-aware overlay network suiting Ad-hoc networks is constructed. The simulation results show that the overlay network constructed in the proposed method can avoid the route being iteratively accessed. Meanwhile, it can effectively minimize the latency and improve the load balance.

  14. Providing interoperability of eHealth communities through peer-to-peer networks.

    Science.gov (United States)

    Kilic, Ozgur; Dogac, Asuman; Eichelberg, Marco

    2010-05-01

    Providing an interoperability infrastructure for Electronic Healthcare Records (EHRs) is on the agenda of many national and regional eHealth initiatives. Two important integration profiles have been specified for this purpose, namely, the "Integrating the Healthcare Enterprise (IHE) Cross-enterprise Document Sharing (XDS)" and the "IHE Cross Community Access (XCA)." IHE XDS describes how to share EHRs in a community of healthcare enterprises and IHE XCA describes how EHRs are shared across communities. However, the current version of the IHE XCA integration profile does not address some of the important challenges of cross-community exchange environments. The first challenge is scalability. If every community that joins the network needs to connect to every other community, i.e., a pure peer-to-peer network, this solution will not scale. Furthermore, each community may use a different coding vocabulary for the same metadata attribute, in which case, the target community cannot interpret the query involving such an attribute. Yet another important challenge is that each community may (and typically will) have a different patient identifier domain. Querying for the patient identifiers in the target community using patient demographic data may create patient privacy concerns. In this paper, we address each of these challenges and show how they can be handled effectively in a superpeer-based peer-to-peer architecture.

  15. Key Management Schemes for Peer-to-Peer Multimedia Streaming Overlay Networks

    Science.gov (United States)

    Naranjo, J. A. M.; López-Ramos, J. A.; Casado, L. G.

    Key distribution for multimedia live streaming peer-to-peer overlay networks is a field still in its childhood stage. A scheme designed for networks of this kind must seek security and efficiency while keeping in mind the following restrictions: limited bandwidth, continuous playing, great audience size and clients churn. This paper introduces two novel schemes that allow a trade-off between security and efficiency by allowing to dynamically vary the number of levels used in the key hierarchy. These changes are motivated by great variations in audience size, and initiated by decision of the Key Server. Additionally, a comparative study of both is presented, focusing on security and audience size. Results show that larger key hierarchies can supply bigger audiences, but offer less security against statistical attacks. The opposite happens for shorter key hierarchies.

  16. Modeling Peer-to-Peer Botnet on Scale-Free Network

    Directory of Open Access Journals (Sweden)

    Liping Feng

    2014-01-01

    Full Text Available Peer-to-peer (P2P botnets have emerged as one of the serious threats to Internet security. To prevent effectively P2P botnet, in this paper, a mathematical model which combines the scale-free trait of Internet with the formation of P2P botnet is presented. Explicit mathematical analysis demonstrates that the model has a globally stable endemic equilibrium when infection rate is greater than a critical value. Meanwhile, we find that, in scale-free network, the critical value is very little. Hence, it is unrealistic to completely dispel the P2P botnet. Numerical simulations show that one can take effective countermeasures to reduce the scale of P2P botnet or delay its outbreak. Our findings can provide meaningful instruction to network security management.

  17. A distributed information retrieval method in peer-to-peer network

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To avoid the scalability of the existing systems that employed centralized indexing, index flooding or query flooding, we proposed an efficient peer-to-peer information retrieval system SPIRS (Semantic P2P-based Information Retrieval System) that supported state-of-the-art content and semantic searches. SPIRS distributes document indices through P2P network hierarchically by Latent Semantic Indexing (LSI) and organizes nodes into a hierarchical overlay through CAN and TRIE. Comparing with other P2P search techniques, those based on simple keyword matching, SPIRS has better accuracy for considering the advanced relevance among documents. Given a query, only a small number of nodes are needed for SPIRS to identify the matching documents.Furthermore, both theoretical analysis and experimental results show that SPIRS possesses higher accuracy and less logic hops.

  18. Efficient content distribution for peer-to-peer overlays on mobile ad hoc networks

    Directory of Open Access Journals (Sweden)

    Afzal Mawji

    2011-07-01

    Full Text Available Peer-to-peer (P2P networks existing on a MANET are a natural evolution since both are decentralized and have dynamic topologies. As MANETs grow in use due to the increasing popularity of wireless mesh and 4G networks, it is expected that P2P applications will remain as a popular means of obtaining files. Network coding has been shown as an efficient means of sharing large files in a P2P network. With network coding, all file blocks have the same relative importance. This paper presents an efficient content distribution scheme that uses network coding to share large files in a P2P overlay running on a MANET. Peers request file blocks from multiple server nodes and servers multicast blocks to multiple receivers, providing efficient multipoint-to-multipoint communication. Simulation results show that compared to other common download techniques, the proposed scheme performs very well, having lower download time and energy consumption. Also, more peers participate in uploading the file, resulting in greater fairness.

  19. A Local Asynchronous Distributed Privacy Preserving Feature Selection Algorithm for Large Peer-to-Peer Networks

    Data.gov (United States)

    National Aeronautics and Space Administration — In this paper we develop a local distributed privacy preserving algorithm for feature selection in a large peer-to-peer environment. Feature selection is often used...

  20. Secure Peer-to-Peer Networks for Scientific Information Sharing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our goal is to adapt the peer?to?peer technology (P2P), which has been overwhelmingly successful in popular content distribution, as the basis for development of...

  1. A Local Scalable Distributed Expectation Maximization Algorithm for Large Peer-to-Peer Networks

    Data.gov (United States)

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

  2. Multi-objective optimization based privacy preserving distributed data mining in Peer-to-Peer networks

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper proposes a scalable, local privacy preserving algorithm for distributed Peer-to-Peer (P2P) data aggregation useful for many advanced data mining/analysis...

  3. Improving the Performance of the Peer to Peer Network by Introducing an Assortment of Methods

    Directory of Open Access Journals (Sweden)

    M. S. Sendil

    2011-01-01

    Full Text Available Problem Statement: Peer to Peer (P2P systems have grown dramatically in recent years. The most popular type of P2P systems are file sharing networks, which are used to share various types of content over the Internet. Due to the increase in popularity of P2P systems, the network performance of these systems has become a very important issue in the design and realization of these networks. Hence, the performance of the P2P has been improved. Approach: This paper suggests the following methods for the improving the performance of P2P systems: Method-1: Improving the P2P routing using a sandwich technique. Method-2: Improving the search performance by introducing a new searching method based on the super peer. Method-3: Improving the search by introducing a ranking algorithm based on the knowledge database. Results: The system demonstrates that the methods introduced here have improved the performance of P2P network efficiently when compared to the existing methodologies. Conclusions / Recommendations: The performance of the P2P systems have improved by using the above said methods, hence the traffic can be reduced in P2P network.

  4. Towards Robust and Efficient Computation in Dynamic Peer-to-Peer Networks

    CERN Document Server

    Augustine, John; Robinson, Peter; Upfal, Eli

    2011-01-01

    Motivated by the need for robust and fast distributed computation in highly dynamic Peer-to-Peer (P2P) networks, we study algorithms for the fundamental distributed agreement problem. P2P networks are highly dynamic networks that experience heavy node {\\em churn} (i.e., nodes join and leave the network continuously over time). Our main contributions are randomized distributed algorithms that guarantee {\\em stable almost-everywhere agreement} with high probability even under high adversarial churn in polylogarithmic number of rounds. In particular, we present the following results: 1. An $O(\\log^2 n)$-round ($n$ is the stable network size) randomized algorithm that achieves almost-everywhere agreement with high probability under up to {\\em linear} churn {\\em per round} (i.e., $\\epsilon n$, for some small constant $\\epsilon > 0$), assuming that the churn is controlled by an oblivious adversary (has complete knowledge and control of what nodes join and leave and at what time and has unlimited computational power...

  5. Peer-to-peer model for the area coverage and cooperative control of mobile sensor networks

    Science.gov (United States)

    Tan, Jindong; Xi, Ning

    2004-09-01

    This paper presents a novel model and distributed algorithms for the cooperation and redeployment of mobile sensor networks. A mobile sensor network composes of a collection of wireless connected mobile robots equipped with a variety of sensors. In such a sensor network, each mobile node has sensing, computation, communication, and locomotion capabilities. The locomotion ability enhances the autonomous deployment of the system. The system can be rapidly deployed to hostile environment, inaccessible terrains or disaster relief operations. The mobile sensor network is essentially a cooperative multiple robot system. This paper first presents a peer-to-peer model to define the relationship between neighboring communicating robots. Delaunay Triangulation and Voronoi diagrams are used to define the geometrical relationship between sensor nodes. This distributed model allows formal analysis for the fusion of spatio-temporal sensory information of the network. Based on the distributed model, this paper discusses a fault tolerant algorithm for autonomous self-deployment of the mobile robots. The algorithm considers the environment constraints, the presence of obstacles and the nonholonomic constraints of the robots. The distributed algorithm enables the system to reconfigure itself such that the area covered by the system can be enlarged. Simulation results have shown the effectiveness of the distributed model and deployment algorithms.

  6. An Adaptive Failure Detector Based on Quality of Service in Peer-to-Peer Networks

    Directory of Open Access Journals (Sweden)

    Jian Dong

    2014-09-01

    Full Text Available The failure detector is one of the fundamental components that maintain high availability of Peer-to-Peer (P2P networks. Under different network conditions, the adaptive failure detector based on quality of service (QoS can achieve the detection time and accuracy required by upper applications with lower detection overhead. In P2P systems, complexity of network and high churn lead to high message loss rate. To reduce the impact on detection accuracy, baseline detection strategy based on retransmission mechanism has been employed widely in many P2P applications; however, Chen’s classic adaptive model cannot describe this kind of detection strategy. In order to provide an efficient service of failure detection in P2P systems, this paper establishes a novel QoS evaluation model for the baseline detection strategy. The relationship between the detection period and the QoS is discussed and on this basis, an adaptive failure detector (B-AFD is proposed, which can meet the quantitative QoS metrics under changing network environment. Meanwhile, it is observed from the experimental analysis that B-AFD achieves better detection accuracy and time with lower detection overhead compared to the traditional baseline strategy and the adaptive detectors based on Chen’s model. Moreover, B-AFD has better adaptability to P2P network.

  7. A Robust and Efficient Trust Management Scheme for Peer-to-Peer Networks

    CERN Document Server

    Sen, Jaydip

    2010-01-01

    Studies on the large scale peer-to-peer (P2P) network like Gnutella have shown the presence of large number of free riders. Moreover, the open and decentralized nature of P2P network is exploited by malicious users who distribute unauthentic or harmful contents. Despite the existence of a number of trust management schemes in the literature for combating against free riding and distribution of malicious files, these mechanisms are not scalable due to their high computational, communication and storage overhead. These schemes also do not consider effect of trust management on quality-of-service (QoS) of the search. This paper presents a trust management scheme for P2P networks that minimizes distribution of spurious files by a novel technique called topology adaptation. It also reduces search time since most of the queries are resolved within the community of trustworthy peers. Simulation results indicate that the trust management overhead due to the pr oposed mechanism decreases considerably as the network to...

  8. Performance Evaluation of Peer-to-Peer Progressive Download in Broadband Access Networks

    Science.gov (United States)

    Shibuya, Megumi; Ogishi, Tomohiko; Yamamoto, Shu

    P2P (Peer-to-Peer) file sharing architectures have scalable and cost-effective features. Hence, the application of P2P architectures to media streaming is attractive and expected to be an alternative to the current video streaming using IP multicast or content delivery systems because the current systems require expensive network infrastructures and large scale centralized cache storage systems. In this paper, we investigate the P2P progressive download enabling Internet video streaming services. We demonstrated the capability of the P2P progressive download in both laboratory test network as well as in the Internet. Through the experiments, we clarified the contribution of the FTTH links to the P2P progressive download in the heterogeneous access networks consisting of FTTH and ADSL links. We analyzed the cause of some download performance degradation occurred in the experiment and discussed about the effective methods to provide the video streaming service using P2P progressive download in the current heterogeneous networks.

  9. A novel constant degree and constant congestion DHT scheme for peer-to-peer networks

    Institute of Scientific and Technical Information of China (English)

    LI Dongsheng; LU Xicheng

    2005-01-01

    Degree, diameter and congestion are important measures of distributed hash table (DHT) schemes for peer-to-peer networks. Many proposed DHT schemes are based on some traditional interconnection topologies and the Kautz graph is a topology with good properties such as optimal network diameter. In this paper, FissionE, a novel DHT scheme based on the Kautz graph, is proposed. FissionE is the first constant degree and O(logN) diameter DHT scheme with (1+o(1))-congestion. FissionE shows that the DHT scheme with constant degree and constant congestion can achieve O(logN) diameter, which is better than the lower bound Ω(N1/d) conjectured before. The average degree of FissionE is 4 and the diameter is 2*log2N, and the average routing path length is about Iog2N. The average path length of FissionE is shorter than CAN or Koorde with the same degree when the P2P network is large scale.

  10. Targeted Local Immunization in Scale-Free Peer-to-Peer Networks

    Institute of Scientific and Technical Information of China (English)

    Xin-Li Huang; Fu-Tai Zou; Fan-Yuan Ma

    2007-01-01

    The power-law node degree distributions of peer-to-peer overlay networks make them extremely robust torandom failures whereas highly vulnerable under intentional targeted attacks. To enhance attack survivability of these net-works, DeepCure, a novel heuristic immunization strategy, is proposed to conduct decentralized but targeted immunization.Different from existing strategies, DeepCure identifies immunization targets as not only the highly-connected nodes butalso the nodes with high availability and/or high link load, with the aim of injecting immunization information into justright targets to cure. To better trade off the cost and the efficiency, DeepCure deliberately select these targets from 2-1ocalneighborhood, as well as topologically-remote but semantically-close friends if needed. To remedy the weakness of existingstrategies in case of sudden epidemic outbreak, DeepCure is also coupled with a local-hub oriented rate throttling mechanismto enforce proactive rate control. Extensive simulation results show that DeepCure outperforms its competitors, producingan arresting increase of the network attack tolerance, at a lower price of eliminating viruses or malicious attacks.

  11. Trust in social computing. The case of peer-to-peer file sharing networks

    Directory of Open Access Journals (Sweden)

    Heng Xu

    2011-09-01

    Full Text Available Social computing and online communities are changing the fundamental way people share information and communicate with each other. Social computing focuses on how users may have more autonomy to express their ideas and participate in social exchanges in various ways, one of which may be peer-to-peer (P2P file sharing. Given the greater risk of opportunistic behavior by malicious or criminal communities in P2P networks, it is crucial to understand the factors that affect individual’s use of P2P file sharing software. In this paper, we develop and empirically test a research model that includes trust beliefs and perceived risks as two major antecedent beliefs to the usage intention. Six trust antecedents are assessed including knowledge-based trust, cognitive trust, and both organizational and peer-network factors of institutional trust. Our preliminary results show general support for the model and offer some important implications for software vendors in P2P sharing industry and regulatory bodies.

  12. Give-and-take based peer-to-peer content distribution networks

    Indian Academy of Sciences (India)

    Saurabh Aggarwal; Joy Kuri; Chandan Saha

    2014-08-01

    Content Distribution Networks (CDNs) are widely used to distribute data to large number of users. Traditionally, content is being replicated among a number of surrogate servers, leading to high operational costs. In this context, Peer-to-Peer (P2P) CDNs have emerged as a viable alternative. An issue of concern in P2P networks is that of free riders, i.e., selfish peers who download files and leave without uploading anything in return. Free riding must be discouraged. In this paper, we propose a criterion, the Give-and-Take (&) criterion, that disallows free riders. Incorporating the G&T criterion in our model, we study a problem that arises naturally when a new peer enters the system: viz., the problem of downloading a ‘universe’ of segments, scattered among other peers, at low cost. We analyse this $\\mathcal{NP}$−hard problem, and characterize the optimal download cost under the G&T criterion.We propose an optimal algorithm, and provide a sub-optimal algorithm that is nearly optimal, but runs much more quickly; this provides an attractive balance between running time and performance. Finally, we compare the performance of our algorithms with that of a few existing P2P downloading strategies in use. We also study the computation time for prescribing the strategy for initial segment and peer selection for the newly arrived peer for various existing and proposed algorithms, and quantify cost–computation time trade-offs.

  13. Designing ISP-friendly Peer-to-Peer Networks Using Game-based Control

    CERN Document Server

    Reddy, Vinith; Shakkottai, Srinivas; Reddy, A L Narasimha

    2009-01-01

    The rapid growth of peer-to-peer (P2P) networks in the past few years has brought with it increases in transit cost to Internet Service Providers (ISPs), as peers exchange large amounts of traffic across ISP boundaries. This ISP oblivious behavior has resulted in misalignment of incentives between P2P networks--that seek to maximize user quality--and ISPs--that would seek to minimize costs. Can we design a P2P overlay that accounts for both ISP costs as well as quality of service, and attains a desired tradeoff between the two? We design a system, which we call MultiTrack, that consists of an overlay of multiple \\emph{mTrackers} whose purpose is to align these goals. mTrackers split demand from users among different ISP domains while trying to minimize their individual costs (delay plus transit cost) in their ISP domain. We design the signals in this overlay of mTrackers in such a way that potentially competitive individual optimization goals are aligned across the mTrackers. The mTrackers are also capable of...

  14. Comparisons process-to-bay level peer-to-peer network delay in IEC 61850 substation communication systems

    Directory of Open Access Journals (Sweden)

    Nasser Hasan Ali

    2014-12-01

    Full Text Available This paper presents the application of IEC 61850 protocol in electrical power engineering industry for data communication systems between substations. This IEC 61850 protocol presents new challenges for real-time communication performance between Intelligent Electronic Devices (IEDs within substation because of the Generic Object Oriented Substation Event (GOOSE messages. The analyses of substation Ethernet and WLAN (wireless LAN communication delay, its impact factors, various methods and different network topologies which can improve the real-time performance are discussed. For basic analysis of data flow within a substation, the Optimized Network Engineering Tool (OPNET software is used. The process-to-bay level network simulation model is performed by using the OPNET software. The Ethernet delay and WLAN peer-to-peer performance of the process-to-bay level network simulation results are analyzed which is based on AP (access point, switched, shared Ethernet network or peer-to-peer network.

  15. Expertise-based peer selection in Peer-to-Peer networks

    NARCIS (Netherlands)

    Haase, Peter; Siebes, Ronny; Harmelen, van Frank

    2007-01-01

    Peer-to-Peer systems have proven to be an effective way of sharing data. Modern protocols are able to efficiently route a message to a given peer. However, determining the destination peer in the first place is not always trivial. We propose a model in which peers advertise their expertise in the

  16. Expertise-based peer selection in Peer-to-Peer networks

    NARCIS (Netherlands)

    Haase, Peter; Siebes, Ronny; Harmelen, van Frank

    2007-01-01

    Peer-to-Peer systems have proven to be an effective way of sharing data. Modern protocols are able to efficiently route a message to a given peer. However, determining the destination peer in the first place is not always trivial. We propose a a message to a given peer. However, determining the des

  17. A Framework for Distributing Scalable Content over Peer-to-Peer Networks

    NARCIS (Netherlands)

    Eberhard, M.; Kumar, A.; Mignanti, S.; Petrocco, R.; Uitto, M.

    2011-01-01

    Peer-to-Peer systems are nowadays a very popular solution for multimedia distribution, as they provide significant cost benefits compared with traditional server-client distribution. Additionally, the distribution of scalable content enables the consumption of the content in a quality suited for the

  18. PBRRI: A Hybrid Peer-to-Peer Communication Model in Distributed Systems

    Institute of Scientific and Technical Information of China (English)

    张亚英; 尤晋元

    2003-01-01

    In distributed systems independent agents need to interact with each other to accomplish their task.Modern peer-to-peer computing technologies always concern with enabling interaction among agents and help them cooperate with each other. But in fact, access control should also be considered to limit interaction to make it harmless. This paper proposed a proxy based rule regulated interaction (PBRRI) model. Role based access control is introduced for security concerns. Regulation rules are enforced in a distributed manner so that PBRRI can be applied to the open distributed systems such as Internet.

  19. Airborne Network Data Availability Using Peer to Peer Database Replication on a Distributed Hash Table

    Science.gov (United States)

    2013-03-01

    AODV ) were used as the three routing protocols . All routing protocols were configured with the default values of their parameters. The...Optimized Link State Routing OSI Open Systems Interconnection P2P Peer-to-Peer PDP Peer Database Protocol SAR Spatially Aware Routing UAV Unmanned Aerial...concludes that one major aspect is the interaction between two routing systems: the ad-hoc routing protocol and the DHT routing algorithms. Since

  20. Implementation of a public key infrastructure over peer-to-peer network

    OpenAIRE

    Barrera Quintanilla, Xavi

    2007-01-01

    En este proyecto se ha desarrollado la aplicación PKI-P2P, esta aplicación implementa una infraestructura de clave pública (PKI) sobre una red peer-to-peer (P2P). Una PKI tiene como objetivo probar que una clave pública es auténtica para un cierto usuario, porque la confianza que se tiene en una clave pública es muy importante para la seguridad en los métodos criptográficos. Lo normal es que el sistema sea centralizado y jerárquico en donde unos pocos elementos llamados Autoridades de Certifi...

  1. Measuring a year of child pornography trafficking by U.S. computers on a peer-to-peer network.

    Science.gov (United States)

    Wolak, Janis; Liberatore, Marc; Levine, Brian Neil

    2014-02-01

    We used data gathered via investigative "RoundUp" software to measure a year of online child pornography (CP) trafficking activity by U.S. computers on the Gnutella peer-to-peer network. The data include millions of observations of Internet Protocol addresses sharing known CP files, identified as such in previous law enforcement investigations. We found that 244,920 U.S. computers shared 120,418 unique known CP files on Gnutella during the study year. More than 80% of these computers shared fewer than 10 such files during the study year or shared files for fewer than 10 days. However, less than 1% of computers (n=915) made high annual contributions to the number of known CP files available on the network (100 or more files). If law enforcement arrested the operators of these high-contribution computers and took their files offline, the number of distinct known CP files available in the P2P network could be reduced by as much as 30%. Our findings indicate widespread low level CP trafficking by U.S. computers in one peer-to-peer network, while a small percentage of computers made high contributions to the problem. However, our measures were not comprehensive and should be considered lower bounds estimates. Nonetheless, our findings show that data can be systematically gathered and analyzed to develop an empirical grasp of the scope and characteristics of CP trafficking on peer-to-peer networks. Such measurements can be used to combat the problem. Further, investigative software tools can be used strategically to help law enforcement prioritize investigations. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. KRBKSS: a keyword relationship based keyword-set search system for peer-to-peer networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Liang; ZOU Fu-tai; MA Fan-yuan

    2005-01-01

    Distributed inverted index technology is used in many peer-to-peer (P2P) systems to help find rapidly document in -set search system for peer-to-peer networkswhich a given word appears. Distributed inverted index by keywords may incur significant bandwidth for executing more complicated search queries such as multiple-attribute queries. In order to reduce query overhead, KSS (keyword-set search) by Gnawali partitions the index by a set of keywords. However, a KSS index is considerably larger than a standard inverted index,since there are more word sets than there are individual words. And the insert overhead and storage overhead are obviously unacceptable for full-text search on a collection of documents even if KSS uses the distance window technology. In this paper, we extract the relationship information between query keywords from websites' queries logs to improve performance of KSS system.Experiments results clearly demonstrated that the improved keyword-set search system based on keywords relationship (KRBKSS) is more efficient than KSS index in insert overhead and storage overhead, and a standard inverted index in terms of communication costs for query.

  3. A Novel Approach Towards Cost Effective Region-Based Group Key Agreement Protocol for Peer - to - Peer Information Sharing in Mobile Ad Hoc Networks

    CERN Document Server

    Kumar, K; Sumathy, V

    2010-01-01

    Peer-to-peer systems have gained a lot of attention as information sharing systems for the widespread exchange of resources and voluminous information that is easily accessible among thousands of users. However, current peer-to-peer information sharing systems work mostly on wired networks. With the growing number of communication-equipped mobile devices that can self-organize into infrastructure-less communication platform, namely mobile ad hoc networks (MANETs), peer-to-peer information sharing over MANETs becomes a promising research area. In this paper, we propose a Region-Based structure that enables efficient and secure peer-to-peer information sharing over MANETs. The implementation shows that the proposed scheme is Secure, scalable, efficient, and adaptive to node mobility and provides Reliable information sharing.

  4. SFES:A scalable, fault-tolerant, efficient search scheme in a peer-to-peer network

    Institute of Scientific and Technical Information of China (English)

    李振武; 杨舰; 史旭东; 白英彩

    2004-01-01

    This paper presents SFES: a scalable, fault-tolerant, efficient search scheme in a peer-to-peer network. The idea is based on the fact that data distribution in an information society has structured features. We designed an algorithm to cluster peers that have similar interests. When receiving a query request, a peer will preferentially forward it to another peer which belongs to the sane cluster and shares more similar interests. By this method, search efficiency will be remarkably improved and at the same time good resistance against peer failure (the ability to withstand peer failure) is reserved. Keyword partial-match is supported, too.

  5. The Fight Against Piracy in Peer-to-Peer Networks: the Sword of Damocles Hanging over ISP's Head?

    Science.gov (United States)

    Werkers, Evi; Coudert, Fanny

    During the past few years, copyright holders and holders of related rights have started to legally challenge peer-to-peer networks. Their latest strategy consists of trying to actively involve Internet service providers (ISPs) in this combat, e.g. through the implementation of filters. This development raises legal problems and questions both in terms of the liability of ISPs and the protection of privacy of their clients. This chapter discusses the difficult task of balancing copyright interests and fundamental rights which as the European Court of Justice clearly stated in the Promusicae case remains a matter of Member States.

  6. Enhancing and Analyzing Search performance in Unstructured Peer to Peer Networks Using Enhanced Guided search protocol (EGSP)

    CERN Document Server

    Anusuya, R; Julie, E Golden

    2010-01-01

    Peer-to-peer (P2P) networks establish loosely coupled application-level overlays on top of the Internet to facilitate efficient sharing of resources. It can be roughly classified as either structured or unstructured networks. Without stringent constraints over the network topology, unstructured P2P networks can be constructed very efficiently and are therefore considered suitable to the Internet environment. However, the random search strategies adopted by these networks usually perform poorly with a large network size. To enhance the search performance in unstructured P2P networks through exploiting users' common interest patterns captured within a probability-theoretic framework termed the user interest model (UIM). A search protocol and a routing table updating protocol are further proposed in order to expedite the search process through self organizing the P2P network into a small world. Both theoretical and experimental analyses are conducted and demonstrated the effectiveness and efficiency of the appro...

  7. Delay-sensitive content distribution via peer-to-peer collaboration in public safety vehicular ad-hoc networks

    KAUST Repository

    Atat, Rachad

    2014-05-01

    Delay-sensitive content distribution with peer-to-peer (P2P) cooperation in public safety vehicular networks is investigated. Two cooperative schemes are presented and analyzed. The first scheme is based on unicasting from the base station, whereas the second is based on threshold based multicasting. Long Term Evolution (LTE) is used for long range (LR) communications with the base station (BS) and IEEE 802.11p is considered for inter-vehicle collaboration on the short range (SR). The first scheme is shown to outperform non-cooperative unicasting and multicasting, while the second scheme outperforms non-cooperative unicasting beyond a specific number of cooperating vehicles, when the appropriate 802.11p power class is used. The first scheme achieves the best performance among the compared methods, and a practical approximation of that scheme is shown to be close to optimal performance. © 2014 Elsevier B.V. All rights reserved.

  8. Challenges to Participation in the Sharing Economy: The Case of Local Online Peer-to-Peer Exchange in a Single Parents’ Network

    Directory of Open Access Journals (Sweden)

    Airi Lampinen

    2015-05-01

    Full Text Available This paper depicts an initiative to deploy an online peer-to-peer exchange system for a community network of single parents – a group of people in need of goods, services, and social support in their local neighborhoods. We apply participant observation and semi-structured interviews to uncover key issues that can hinder the emergence of sharing practices in local community networks of this type. Our study illustrates how pressures related to single parenthood can impede opportunities to engage in peer-to-peer exchange, even when community members view the social and material benefits of participation as desirable and necessary. This complicates the prevalent narrative that local peer-to-peer exchange systems are an accessible and convenient alternative to traditional markets. Moreover, we discuss our collaboration with the community as well as the developers of the sharing platform, highlighting the challenges of user-centered design in the sharing economy.

  9. Alpha Multipliers Breadth-First Search Technique for Resource Discovery in Unstructured Peer-to-Peer Networks

    Directory of Open Access Journals (Sweden)

    Azrul Amri Jamal

    2017-08-01

    Full Text Available Resource discovery in unstructured peer-to-peer (P2P networks is important in the field of grid computing. Breadth-first search (BFS is widely used for resource discovery in unstructured P2P networks. The technique is proven to return as many search results as possible. However, the network cost of the technique is high due to the flooding of query messages that can degenerate the performance of the whole network. The objective of this study is to optimise the BFS technique, so that it will produce good search results without flooding the network with unnecessary walkers. Several resource discovery techniques used in unstructured P2P networks are discussed and categorised. P2P simulators that are used for P2P network experiments were studied in accordance to their characteristics such as, scalability, extensibility and support status. Several network topology generators were also scrutinised and selected in order to find out the most real-life like network generation model for unstructured P2P experiments. Multiple combinations of five-tuple alpha multipliers have been experimented to find out the best set to make -BFS. In our test, the -BFS increases the query efficiency of the conventional BFS from 55.67% to 63.15%.

  10. Inadvertent Exposure to Pornography on the Internet: Implications of Peer-to-Peer File-Sharing Networks for Child Development and Families

    Science.gov (United States)

    Greenfield, P.M.

    2004-01-01

    This essay comprises testimony to the Congressional Committee on Government Reform. The Committee's concern was the possibility of exposure to pornography when children and teens participate in peer-to-peer file-sharing networks, which are extremely popular in these age groups. A review of the relevant literature led to three major conclusions:…

  11. An Optimal Pull-Push Scheduling Algorithm Based on Network Coding for Mesh Peer-to-Peer Live Streaming

    Science.gov (United States)

    Cui, Laizhong; Jiang, Yong; Wu, Jianping; Xia, Shutao

    Most large-scale Peer-to-Peer (P2P) live streaming systems are constructed as a mesh structure, which can provide robustness in the dynamic P2P environment. The pull scheduling algorithm is widely used in this mesh structure, which degrades the performance of the entire system. Recently, network coding was introduced in mesh P2P streaming systems to improve the performance, which makes the push strategy feasible. One of the most famous scheduling algorithms based on network coding is R2, with a random push strategy. Although R2 has achieved some success, the push scheduling strategy still lacks a theoretical model and optimal solution. In this paper, we propose a novel optimal pull-push scheduling algorithm based on network coding, which consists of two stages: the initial pull stage and the push stage. The main contributions of this paper are: 1) we put forward a theoretical analysis model that considers the scarcity and timeliness of segments; 2) we formulate the push scheduling problem to be a global optimization problem and decompose it into local optimization problems on individual peers; 3) we introduce some rules to transform the local optimization problem into a classical min-cost optimization problem for solving it; 4) We combine the pull strategy with the push strategy and systematically realize our scheduling algorithm. Simulation results demonstrate that decode delay, decode ratio and redundant fraction of the P2P streaming system with our algorithm can be significantly improved, without losing throughput and increasing overhead.

  12. Cooperative Networked Control of Dynamical Peer-to-Peer Vehicle Systems

    Science.gov (United States)

    2007-12-28

    properties expressed in CTL . Also developed have been learning algorithms for boolean programs, which are sequential, recursive programs over boolean...range of commercial andr military communication systems such as mobile networks (For command and control) and hylbrid networks tlha.t include wired aml

  13. A New Approach to Cold Start in Peer-to-Peer File Sharing Networks

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Nematbakhsh

    2009-11-01

    Full Text Available Solving free riding and selecting a reliable service provider in P2P networks has been separately investigated in last few years. Using trust has shown to be one of the best ways of solving these problems. But using this approach to simultaneously deal with both problems makes it impossible for newcomers to join the network and the expansion of network is prevented. In this paper we used the game theory to model the behavior of peers and developed a mechanism in which free riding and providing bad service are dominated strategies for peers. At the same time newcomers can participate and are encouraged to be active in the network. The proposed model has been simulated and the results showed that the trust value of free riders and bad service providers converge to a finite value and trust of peers who provide good service is monotonically increased despite the time they join the network.

  14. Video Streaming in Peer-to-Peer Networks Using Network Coding Renders Efficient Video Cassette Recorder Operations

    Directory of Open Access Journals (Sweden)

    K. V. Pradeepthi

    2012-01-01

    Full Text Available Problem statement: Major technological development in recent years has led to the usage of shared streaming solutions by Peer-to-Peer (P2P Video-on-Demand (VoD systems in the Internet. Video streaming in P2P network systems has ample amount of loss of video packets due to network disabilities such as congestion, intrusion, connectivity problems, excessive network collisions etc. Adding onto the video streaming problems, Video Cassette Recorder (VCR operations require flexibility of playback to the user. So, any missing or randomized packets from the video have to be instantaneously corrected and generated appropriately. Approach: In this paper, we study the working of VoD streaming system that uses Network Coding (NC for improving the delivered video content at the end-user by correcting the error packets. We, study that NC not only, materializes uninterrupted playback but efficiency in VCR operations particularly, the seek operation have also improved the user perceived quality of videos. Our setup handles the NC generator present at the proxy between the media server and the peer clients, reducing the overhead at the server. The relevant packets that are lost within each peer-client are generated with the NC packets. Results: The receiver detects error due to loss of packets and corrects at a much faster pace than the time consumed for retransmission. This helps in improving user efficiency in VCR operations also. Though, NC provides added advantage in P2P VoD systems, there is initial transmission delay, a time cost incurred in video streaming. This time cost is rather small when compared to the difficulties within the Internet for the retransmissions. Conclusion: From the study we observe, that NC when applied to P2P VoD has few difficulties. They are complexity in implementing NC and tradeoffs on the part of NC in video streaming. Based on time and cache constraints these difficulties are not overwhelming when the actual benefits reaped are

  15. Exploring a QoS Driven Scheduling Approach for Peer-to-Peer Live Streaming Systems with Network Coding

    Science.gov (United States)

    Cui, Laizhong; Lu, Nan; Chen, Fu

    2014-01-01

    Most large-scale peer-to-peer (P2P) live streaming systems use mesh to organize peers and leverage pull scheduling to transmit packets for providing robustness in dynamic environment. The pull scheduling brings large packet delay. Network coding makes the push scheduling feasible in mesh P2P live streaming and improves the efficiency. However, it may also introduce some extra delays and coding computational overhead. To improve the packet delay, streaming quality, and coding overhead, in this paper are as follows. we propose a QoS driven push scheduling approach. The main contributions of this paper are: (i) We introduce a new network coding method to increase the content diversity and reduce the complexity of scheduling; (ii) we formulate the push scheduling as an optimization problem and transform it to a min-cost flow problem for solving it in polynomial time; (iii) we propose a push scheduling algorithm to reduce the coding overhead and do extensive experiments to validate the effectiveness of our approach. Compared with previous approaches, the simulation results demonstrate that packet delay, continuity index, and coding ratio of our system can be significantly improved, especially in dynamic environments. PMID:25114968

  16. Exploring a QoS Driven Scheduling Approach for Peer-to-Peer Live Streaming Systems with Network Coding

    Directory of Open Access Journals (Sweden)

    Laizhong Cui

    2014-01-01

    Full Text Available Most large-scale peer-to-peer (P2P live streaming systems use mesh to organize peers and leverage pull scheduling to transmit packets for providing robustness in dynamic environment. The pull scheduling brings large packet delay. Network coding makes the push scheduling feasible in mesh P2P live streaming and improves the efficiency. However, it may also introduce some extra delays and coding computational overhead. To improve the packet delay, streaming quality, and coding overhead, in this paper are as follows. we propose a QoS driven push scheduling approach. The main contributions of this paper are: (i We introduce a new network coding method to increase the content diversity and reduce the complexity of scheduling; (ii we formulate the push scheduling as an optimization problem and transform it to a min-cost flow problem for solving it in polynomial time; (iii we propose a push scheduling algorithm to reduce the coding overhead and do extensive experiments to validate the effectiveness of our approach. Compared with previous approaches, the simulation results demonstrate that packet delay, continuity index, and coding ratio of our system can be significantly improved, especially in dynamic environments.

  17. Publishing and Discovery of Mobile Web Services in Peer to Peer Networks

    CERN Document Server

    Srirama, Satish Narayana

    2010-01-01

    It is now feasible to host Web Services on a mobile device due to the advances in cellular devices and mobile communication technologies. However, the reliability, usability and responsiveness of the Mobile Hosts depend on various factors including the characteristics of available network, computational resources, and better means of searching the services provided by them. P2P enhances the adoption of Mobile Host in commercial environments. Mobile Hosts in P2P can collaboratively share the resources of individual peers. P2P also enhances the service discovery of huge number of Web Services possible with Mobile Hosts. Advanced features like post filtering with weight of keywords and context-awareness can also be exploited to select the best possible mobile Web Service. This paper proposes the concept of Mobile Hosts in P2P networks and identifies the means of publishing and discovery of Web Services in mobile P2P networks.

  18. A GRADE-BASED INCENTIVE MECHANISM FOR PEER-TO-PEER NETWORKS

    Directory of Open Access Journals (Sweden)

    S. Moses Dian

    2012-01-01

    Full Text Available Free-riding is a desperate and a constant menace to many P2P systems, to violate the cooperation among peers. This study proposes a grade-based approach, which expeditiously maintains fairness in the network by encouraging the high contributed peers and altogether wiping out the free-riders. The Network Contribution Ratio determines the contribution of users globally. Besides, the proposed grading algorithm uses a point-based incentive mechanism which provides credit points to the users with respect to their grade and the transfer of users between each grade is instituted.

  19. Regulating peer-to-peer network currency : Lessons from Napster and payment Systems

    NARCIS (Netherlands)

    Kasiyanto, Safari

    2015-01-01

    It was only yesterday when the central banks across the world shared a similar concerns about the rise of e-money as a ‘new’ form of money. Theoretically, e-money as a network good has the potential to achieve a position necessary to replace traditional money. If this happens, the central bank’s tas

  20. Regulating peer-to-peer network currency : Lessons from Napster and payment Systems

    NARCIS (Netherlands)

    Kasiyanto, Safari

    2015-01-01

    It was only yesterday when the central banks across the world shared a similar concerns about the rise of e-money as a ‘new’ form of money. Theoretically, e-money as a network good has the potential to achieve a position necessary to replace traditional money. If this happens, the central bank’s tas

  1. Regulating peer-to-peer network currency : Lessons from Napster and payment Systems

    NARCIS (Netherlands)

    Kasiyanto, Safari

    2015-01-01

    It was only yesterday when the central banks across the world shared a similar concerns about the rise of e-money as a ‘new’ form of money. Theoretically, e-money as a network good has the potential to achieve a position necessary to replace traditional money. If this happens, the central bank’s

  2. Cooperation stimulation strategies for peer-to-peer wireless live video-sharing social networks.

    Science.gov (United States)

    Lin, W Sabrina; Zhao, H Vicky; Liu, K J Ray

    2010-07-01

    Human behavior analysis in video sharing social networks is an emerging research area, which analyzes the behavior of users who share multimedia content and investigates the impact of human dynamics on video sharing systems. Users watching live streaming in the same wireless network share the same limited bandwidth of backbone connection to the Internet, thus, they might want to cooperate with each other to obtain better video quality. These users form a wireless live-streaming social network. Every user wishes to watch video with high quality while paying as little as possible cost to help others. This paper focuses on providing incentives for user cooperation. We propose a game-theoretic framework to model user behavior and to analyze the optimal strategies for user cooperation simulation in wireless live streaming. We first analyze the Pareto optimality and the time-sensitive bargaining equilibrium of the two-person game. We then extend the solution to the multiuser scenario. We also consider potential selfish users' cheating behavior and malicious users' attacking behavior and analyze the performance of the proposed strategies with the existence of cheating users and malicious attackers. Both our analytical and simulation results show that the proposed strategies can effectively stimulate user cooperation, achieve cheat free and attack resistance, and help provide reliable services for wireless live streaming applications.

  3. ISS: Efficient Search Scheme Based on Immune Method in Modern Unstructured Peer-to-Peer Networks

    Institute of Scientific and Technical Information of China (English)

    GUAN Zhitao; CAO Yuanda; ZHU Liehuang; ZHANG Changyou; FAN Xiumei

    2007-01-01

    Flooding is the most famous technique for locating contents in unstructured P2P networks. Recently traditional flooding has been replaced by more efficient dynamic query (DQ) and different variants of such algorithms. Dynamic query is a new flooding technique which could estimate a proper time-to-live (TTL) value for a query flooding by estimating the popularity of the searched files, and retrieve sufficient results under controlled flooding range for reducing network traffic. However, all DQ-like search algorithms are "blind" so that a large amount of redundant messages are caused. In this paper, we proposed a new search scheme, called Immune Search Scheme (ISS), to cope with this problem. In ISS, an immune systems inspired concept of similarity-governed clone proliferation and mutation for query message movement is applied. Some assistant strategies, that is, shortcuts creation and peer traveling are incorporated into ISS to develop "immune memory" for improving search performance, which can make ISS not be blind but heuristic.

  4. MATIN: a random network coding based framework for high quality peer-to-peer live video streaming.

    Science.gov (United States)

    Barekatain, Behrang; Khezrimotlagh, Dariush; Aizaini Maarof, Mohd; Ghaeini, Hamid Reza; Salleh, Shaharuddin; Quintana, Alfonso Ariza; Akbari, Behzad; Cabrera, Alicia Triviño

    2013-01-01

    In recent years, Random Network Coding (RNC) has emerged as a promising solution for efficient Peer-to-Peer (P2P) video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay.

  5. MATIN: a random network coding based framework for high quality peer-to-peer live video streaming.

    Directory of Open Access Journals (Sweden)

    Behrang Barekatain

    Full Text Available In recent years, Random Network Coding (RNC has emerged as a promising solution for efficient Peer-to-Peer (P2P video multicasting over the Internet. This probably refers to this fact that RNC noticeably increases the error resiliency and throughput of the network. However, high transmission overhead arising from sending large coefficients vector as header has been the most important challenge of the RNC. Moreover, due to employing the Gauss-Jordan elimination method, considerable computational complexity can be imposed on peers in decoding the encoded blocks and checking linear dependency among the coefficients vectors. In order to address these challenges, this study introduces MATIN which is a random network coding based framework for efficient P2P video streaming. The MATIN includes a novel coefficients matrix generation method so that there is no linear dependency in the generated coefficients matrix. Using the proposed framework, each peer encapsulates one instead of n coefficients entries into the generated encoded packet which results in very low transmission overhead. It is also possible to obtain the inverted coefficients matrix using a bit number of simple arithmetic operations. In this regard, peers sustain very low computational complexities. As a result, the MATIN permits random network coding to be more efficient in P2P video streaming systems. The results obtained from simulation using OMNET++ show that it substantially outperforms the RNC which uses the Gauss-Jordan elimination method by providing better video quality on peers in terms of the four important performance metrics including video distortion, dependency distortion, End-to-End delay and Initial Startup delay.

  6. Modeling structured peer-to-peer systems

    Institute of Scientific and Technical Information of China (English)

    HAN Li; LEI Zhen-ming

    2006-01-01

    Distributed network architecture and dynamic change of nodes makes the operation of structured peer-to-peer networks unpredictable. This article aims to present a research on the running rule of structured peer-to-peer networks through a mathematical model. The proposed model provides a low-complexity means to estimate the performance of a structured peer-to-peer network from two aspects: the average existent time of a node and probability of returning to a temporarily steady state of network. On the basis of the results, it can be concluded that the proposed structured peer-to-peer network is suitable for those conditions where the frequency of node change is under limited value, and this value mainly depends on the initializing time of the node. Otherwise,structured peer-to-peer network can be abstracted as a network queuing system, which is composed of many node queuing systems in a meshy way and the relation between the throughput of the node system and network system is analyzed.

  7. Wi-Fi Walkman: A wireless handhold that shares and recommends music on peer-to-peer networks

    NARCIS (Netherlands)

    Wang, J.; Reinders, M.J.T.; Pouwelse, J.; Lagendijk, R.L.

    2005-01-01

    The Wi-Fi walkman is a mobile multimedia application that we developed to investigate the technological and usability aspects of human-computer interaction with personalized, intelligent and context-aware wearable devices in peer-to-peer wireless environments such as the future home, office, or

  8. Efficiently Delivering Data Packets Using Distributed Protocol for Runtime Groups Formed In Peer-to-Peer Network

    Directory of Open Access Journals (Sweden)

    Yasa Ramya

    2011-09-01

    Full Text Available Peer-to-Peer streaming has been widely used over the internet, where a streaming system usually has multiple channels and peers may form multiple groups for content distribution. In this paper, we propose a distributed overlay framework called SMesh (subset-mesh for dynamic groups where users may frequently hop from one group to another. SMesh first builds a relatively stable mesh consisting of all hosts for control messaging. The mesh supports dynamic host joining and leaving, and construction of delivery trees. Using the Delaunay Triangulation protocol as an example, we show how to construct an efficient mesh with low maintenance cost. We also study about various tree constructions based on the mesh, including embedded, bypass, and intermediate trees.

  9. Efficient Skyline Computation in Structured Peer-to-Peer Systems

    DEFF Research Database (Denmark)

    Cui, Bin; Chen, Lijiang; Xu, Linhao;

    2009-01-01

    An increasing number of large-scale applications exploit peer-to-peer network architecture to provide highly scalable and flexible services. Among these applications, data management in peer-to-peer systems is one of the interesting domains. In this paper, we investigate the multidimensional skyl...

  10. An Agent-Based Model of Private Woodland Owner Management Behavior Using Social Interactions, Information Flow, and Peer-To-Peer Networks.

    Science.gov (United States)

    Huff, Emily Silver; Leahy, Jessica E; Hiebeler, David; Weiskittel, Aaron R; Noblet, Caroline L

    2015-01-01

    Privately owned woodlands are an important source of timber and ecosystem services in North America and worldwide. Impacts of management on these ecosystems and timber supply from these woodlands are difficult to estimate because complex behavioral theory informs the owner's management decisions. The decision-making environment consists of exogenous market factors, internal cognitive processes, and social interactions with fellow landowners, foresters, and other rural community members. This study seeks to understand how social interactions, information flow, and peer-to-peer networks influence timber harvesting behavior using an agent-based model. This theoretical model includes forested polygons in various states of 'harvest readiness' and three types of agents: forest landowners, foresters, and peer leaders (individuals trained in conservation who use peer-to-peer networking). Agent rules, interactions, and characteristics were parameterized with values from existing literature and an empirical survey of forest landowner attitudes, intentions, and demographics. The model demonstrates that as trust in foresters and peer leaders increases, the percentage of the forest that is harvested sustainably increases. Furthermore, peer leaders can serve to increase landowner trust in foresters. Model output and equations will inform forest policy and extension/outreach efforts. The model also serves as an important testing ground for new theories of landowner decision making and behavior.

  11. Swarm-Evolution-based Reputation Model for Peer-to-Peer Networks%对等网中基于种群进化的信誉模型

    Institute of Scientific and Technical Information of China (English)

    鲍翊平; 姚莉; 张维明; 唐九阳

    2011-01-01

    信誉系统是应对对等网信任危机的关键途径.提出了一种新的基于种群进化的信誉模型.该模型将对等网视为社会生态系统,将节点的信誉评估过程模型化为一种进化过程,通过引入交叉和变异,节点能快速有效地评估潜在交易对象的信任度,从而最终提高其网络适应能力.通过仿真对模型进行了验证.%Reputation system is the key approach to fight against the trust crisis of Peer-to-Peer networks. A novel reputation model based on swarm evolution was proposed in this article. In the model, the Peer-to-Peer network is viewed as social ecosystem, the process of reputation evaluation is modeled as an evolutionary process for peers. By using the strategy of crossover and selection, the peers can rapidly and efficiently evaluate the trust value of potential partners,and finally improve the ability of their fitness. In order for verifying its performance, a simulation experiment for this model was also provided.

  12. An Agent-Based Model of Private Woodland Owner Management Behavior Using Social Interactions, Information Flow, and Peer-To-Peer Networks.

    Directory of Open Access Journals (Sweden)

    Emily Silver Huff

    Full Text Available Privately owned woodlands are an important source of timber and ecosystem services in North America and worldwide. Impacts of management on these ecosystems and timber supply from these woodlands are difficult to estimate because complex behavioral theory informs the owner's management decisions. The decision-making environment consists of exogenous market factors, internal cognitive processes, and social interactions with fellow landowners, foresters, and other rural community members. This study seeks to understand how social interactions, information flow, and peer-to-peer networks influence timber harvesting behavior using an agent-based model. This theoretical model includes forested polygons in various states of 'harvest readiness' and three types of agents: forest landowners, foresters, and peer leaders (individuals trained in conservation who use peer-to-peer networking. Agent rules, interactions, and characteristics were parameterized with values from existing literature and an empirical survey of forest landowner attitudes, intentions, and demographics. The model demonstrates that as trust in foresters and peer leaders increases, the percentage of the forest that is harvested sustainably increases. Furthermore, peer leaders can serve to increase landowner trust in foresters. Model output and equations will inform forest policy and extension/outreach efforts. The model also serves as an important testing ground for new theories of landowner decision making and behavior.

  13. Peer-to-Peer Data Mining, Privacy Issues, and Games

    Data.gov (United States)

    National Aeronautics and Space Administration — Peer-to-Peer (P2P) networks are gaining increasing popularity in many distributed applications such as file-sharing, network storage, web caching, sear- ching and...

  14. Always-optimally-coordinated candidate selection algorithm for peer-to-peer files sharing system in mobile self-organized networks

    Institute of Scientific and Technical Information of China (English)

    Li Xi; Ji Hong; Zheng Ruiming; Li Ting

    2009-01-01

    In order to improve the performance of peer-to-peer files sharing system under mobile distributed environments, a novel always-optimally-coordinated (AOC) criterion and corresponding candidate selection algorithm are proposed in this paper. Compared with the traditional min-hops criterion, the new approach introduces a fuzzy knowledge combination theory to investigate several important factors that influence files transfer success rate and efficiency. Whereas the min-hops based protocols only ask the nearest candidate peer for desired files, the selection algorithm based on AOC comprehensively considers users' preference and network requirements with flexible balancing rules. Furthermore, its advantage also expresses in the independence of specified resource discovering protocols, allowing for scalability. The simulation results show that when using the AOC based peer selection algorithm, system performance is much better than the min-hops scheme, with files successful transfer rate improved more than 50% and transfer time reduced at least 20%.

  15. Research on Application of Simulators for Overlays in Mobile Peer-to-Peer Networks%移动对等网络覆盖网模拟器比较与开发

    Institute of Scientific and Technical Information of China (English)

    李军

    2015-01-01

    为了确定已有的通用网络模拟器和P2 P网络模拟器能否很好的支持移动对等网络模拟,比较和分析了已有的二十余种网络模拟器的特性,得出了仅有极少数网络模拟器较适合移动对等网络覆盖网模拟的结论,并以其中一种模拟器为例,给出了移动对等网络覆盖网模拟的开发步骤,最后提出了移动对等网络覆盖网模拟器的发展方向.%As the research of mobile peer-to-peer network comes to be in-depth continuously, evaluation and comparison of different overlay networks become a problem, urgently to be solved. Although the network protocols can be compared through theo-retical calculation and system emulation, the network simulation method has a unique advantage to solve the problem. Therefore, in order to determine whether the existing general network simulator and peer-to-peer (P2P) network simulator can well support mobile peer-to-peer network simulation, the characteristics of more than twenty kinds of the existing network simulators are com-pared and analyzed. It is concluded that only few kinds of network simulators are suitable for mobile peer-to-peer network simula-tion. Taken one of them as an example, it shows the development steps of mobile peer-to-peer network simulation. At the end, it gives the developing direction of mobile P2P overlay network simulators.

  16. Handbook on theoretical and algorithmic aspects of sensor, ad hoc wireless, and peer-to-peer networks

    CERN Document Server

    Wu, Jie

    2005-01-01

    PrefaceAD HOC WIRELESS NETWORKSA Modular Cross Layer Architecture for Ad Hoc Networks, M. Conti, J. Crowcroft, G. Maselli, and G. TuriRouting Scalability in MANETs, J. Eriksson, S. Krishnamurthy and M. FaloutsosUniformly Distributed Algorithm for Virtual Backbone Routing in Ad Hoc Wireless Networks, D.S. KimMaximum Necessary Hop Count for Packet Routing in MANET, X. Chen and J. ShenEfficient Strategyproof Multicast in Selfish Wireless Networks, X.-Yang LiGeocasting in Ad Hoc and Sensor Networks, I. StojmenovicTopology Control for Ad hoc Networks: Present Solutions and Open Issues, C.-C. Shen a

  17. Two Dimensional Array Based Overlay Network for Balancing Load of Peer-to-Peer Live Video Streaming

    Science.gov (United States)

    Faruq Ibn Ibrahimy, Abdullah; Rafiqul, Islam Md; Anwar, Farhat; Ibn Ibrahimy, Muhammad

    2013-12-01

    The live video data is streaming usually in a tree-based overlay network or in a mesh-based overlay network. In case of departure of a peer with additional upload bandwidth, the overlay network becomes very vulnerable to churn. In this paper, a two dimensional array-based overlay network is proposed for streaming the live video stream data. As there is always a peer or a live video streaming server to upload the live video stream data, so the overlay network is very stable and very robust to churn. Peers are placed according to their upload and download bandwidth, which enhances the balance of load and performance. The overlay network utilizes the additional upload bandwidth of peers to minimize chunk delivery delay and to maximize balance of load. The procedure, which is used for distributing the additional upload bandwidth of the peers, distributes the additional upload bandwidth to the heterogeneous strength peers in a fair treat distribution approach and to the homogeneous strength peers in a uniform distribution approach. The proposed overlay network has been simulated by Qualnet from Scalable Network Technologies and results are presented in this paper.

  18. Content-specific network analysis of peer-to-peer communication in an online community for smoking cessation

    Science.gov (United States)

    Myneni, Sahiti; Cobb, Nathan K.; Cohen, Trevor

    2016-01-01

    Analysis of user interactions in online communities could improve our understanding of health-related behaviors and inform the design of technological solutions that support behavior change. However, to achieve this we would need methods that provide granular perspective, yet are scalable. In this paper, we present a methodology for high-throughput semantic and network analysis of large social media datasets, combining semi-automated text categorization with social network analytics. We apply this method to derive content-specific network visualizations of 16,492 user interactions in an online community for smoking cessation. Performance of the categorization system was reasonable (average F-measure of 0.74, with system-rater reliability approaching rater-rater reliability). The resulting semantically specific network analysis of user interactions reveals content- and behavior-specific network topologies. Implications for socio-behavioral health and wellness platforms are also discussed. PMID:28269890

  19. A Trust-Based Detection Algorithm of Selfish Packet Dropping Nodes in a Peer-to-Peer Wireless Mesh Network

    CERN Document Server

    Sen, Jaydip

    2010-01-01

    Wireless mesh networks (WMNs) are evolving as a key technology for next-generation wireless networks showing raid progress and numerous applications. These networks have the potential to provide robust and high-throughput data delivery to wireless users. In a WMN, high speed routers equipped with advanced antennas, communicate with each other in a multi-hop fashion over wireless channels and form a broadband backhaul. However, the throughput of a WMN may be severely degraded due to presence of some selfish routers that avoid forwarding packets for other nodes even as they send their own traffic through the network. This paper presents an algorithm for detection of selfish nodes in a WMN that uses statistical theory of inference for reliable clustering of the nodes based on local observations. Simulation results show that the algorithm has a high detection rate and a low false positive rate.

  20. A time-aware hyperlink-induced topic search-based reputation evaluation method for optimal manufacturing service recommendation in distributed peer-to-peer networks

    Directory of Open Access Journals (Sweden)

    Shuai Zhang

    2017-03-01

    Full Text Available With the explosive growth of manufacturing services on a global scale, it has become an enormous challenge to recommend optimal manufacturing service in distributed manufacturing environments. Reputation evaluation is a key step to make optimal manufacturing service recommendation. However, the reputation values calculated through conventional reputation evaluation methods are static and local, and have a severe impact on the effectiveness of manufacturing service recommendation. This article presents a novel and effective reputation evaluation method for optimal manufacturing service recommendation in distributed peer-to-peer networks. The main contribution of the proposed approach is that it makes it possible to calculate the global and dynamic reputation values of enterprises by employing a time-aware hyperlink-induced topic search algorithm. This algorithm not only disseminates the reputation value of transaction enterprises, but also takes account of the temporal dimension in the process of computing reputation values. A concrete example demonstrates the feasibility of calculating reputation values of the proposed method, and an evaluation experiment reveals that both of recall rate and precision rate are improved, employing our proposed method for recommending manufacturing service.

  1. Peer-to-Peer Content Distribution and Over-The-Top TV: An Analysis of Value Networks

    Science.gov (United States)

    de Boever, Jorn; de Grooff, Dirk

    The convergence of Internet and TV, i.e., the Over-The-Top TV (OTT TV) paradigm, created opportunities for P2P content distribution as these systems reduce bandwidth expenses for media companies. This resulted in the arrival of legal, commercial P2P systems which increases the importance of studying economic aspects of these business operations. This chapter examines the value networks of three cases (Kontiki, Zattoo and bittorrent) in order to compare how different actors position and distinguish themselves from competitors by creating value in different ways. The value networks of legal systems have different compositions depending on their market orientation - Business-to-Business (B2B) and/or Businessto- Consumer (B2C). In addition, legal systems differ from illegal systems as legal companies are not inclined to grant control to users, whereas users havemost control in value networks of illegal, self-organizing file sharing communities. In conclusion, the OTT TV paradigm made P2P technology a partner for the media industry rather than an enemy. However, we argue that the lack of control granted to users will remain a seed-bed for the success of illegal P2P file sharing communities.

  2. LR2: Improving Push-Based Live Streaming and File Sharing in Peer-to-Peer Network

    Directory of Open Access Journals (Sweden)

    Jianwei Zhang

    2014-02-01

    Full Text Available Random scheduling strategy has been emphasized and recommended in push-based P2P streaming systems due to its simplicity and high efficiency, and so is the latest first strategy in file sharing systems. However, how to take advantage of the low playout delay feature in the latest first strategy and the high playout probability feature in the random strategy still remains open. In this paper, we propose the LR2 strategy, which incorporates a segmented chunk selection strategy and a random push strategy. Compared with existent strategies, the LR2 strategy has higher playout probability and lower playout delay in live streaming, and has shorter last finish time in file sharing. On the other hand, live streaming and file sharing are unified into the same modeling framework in our strategy, and we think it can provide fundamental insights into studies on the integrated optimization of live streaming and file sharing in P2P network

  3. Real-time performance of peer-to-peer network%P2P网络的实时性问题

    Institute of Scientific and Technical Information of China (English)

    姚静; 黎忠文; 郭兵

    2011-01-01

    由于P2P网络的动态性、分散性和半可信性,其实时性研究和应用成为公认的难题.当前P2P多媒体应用系统和实时计算系统或多或少采用了实时保障措施,但均没有对P2P实时性进行系统研究.在总结现有P2P网络系统采用的实时技术的基础上,分析了P2P网络结构、搜索协议(算法)和任务调度对实时性的影响,提出P2P网络实时性研究存在的问题,总结出P2P实时性研究需要解决的关键技术.%However,due to the instability, decentralization and semi-trust of the peer-to-peer network, real-time research is a well-known difficult problem.Though many measures had been applied to deal with this problem, there was no systemative research of real-time performance.This paper summarized the real-time technology of P2P network in the past few years, then analyzed the relationship between real-time performance and P2P network architecture, searching protocol (algorithm), task scheduling.In the end, put forward the remaining difficulties and key technologies of real-time performance.

  4. Mobility Helps Peer-to-Peer Security

    DEFF Research Database (Denmark)

    Capkun, Srdjan; Hubaux, Jean-Pierre; Buttyan, Levente

    2006-01-01

    We propose a straightforward technique to provide peer-to-peer security in mobile networks. We show that far from being a hurdle, mobility can be exploited to set up security associations among users. We leverage on the temporary vicinity of users, during which appropriate cryptographic protocols...... are run. We illustrate the operation of the solution in two scenarios, both in the framework of mobile ad hoc networks. In the first scenario, we assume the presence of an offline certification authority and we show how mobility helps to set up security associations for secure routing; in this case......, the security protocol runs over one-hop radio links. We further show that mobility can be used for the periodic renewal of vital security information (e.g., the distribution of hash chain/Merkle tree roots). In the second scenario, we consider fully self-organized security: Users authenticate each other...

  5. Overlook the Trends of Peer-to-Peer Technologies in Future Network%对等网络P2P在未来网络中的发展

    Institute of Scientific and Technical Information of China (English)

    裘晓峰; 马涛; 张春红

    2011-01-01

    The rise of Intemet of things ,mobile Intemet ,cloud computing has formed and changed the features of future network. Correspondingly, peer-to-peer technologies are undergoing new challenges,accompanied by new developing opportunities meanwhile. The advantages and disadvantages of peer-to-peer are pointed out from four dimensions:computing model, network architecture ,service and application ,market and industry, which comprehensively imply the values and problems of peer-to-peer in future network. Combined with the recent research and products, the trends of peer-to-peer are analyzed to give guidance and inspiration to related researchers and engineers.%物联网、移动互联网、云计算、三网融合的兴起正在改变和塑造着未来网络的格局,对等网络P2P在这种新形势下面临着新的考验,同时也存在着新的发展和创新机会.本文结合P2P最新研究进展和市场动态,从计算模式、网络架构、业务应用、市场与产业4个维度分析了P2P的优越和价值所在,突出了P2P的问题和挑战,在此基础上评述了P2P在未来网络中的发展趋势.

  6. Peer-to-Peer Simulation Architecture

    CSIR Research Space (South Africa)

    Duvenhage, B

    2007-06-01

    Full Text Available Distributed parallel and soft real-time simulation architecture is presented. It employs a publish-subscribe communication framework layered on a peer-to-peer Transport Control Protocol-based message passing architecture. Mechanisms for efficient...

  7. Peer-to-Peer Science Data Environment

    Science.gov (United States)

    Byrnes, J. B.; Holland, M. P.

    2004-12-01

    The goal of P2PSDE is to provide a convenient and extensible Peer-to-Peer (P2P) network architecture that allows: distributed science-data services-seamlessly incorporating collaborative value-added services with search-oriented access to remote science data. P2PSDE features the real-time discovery of data-serving peers (plus peer-groups and peer-group services), in addition to the searching for and transferring of science data. These features are implemented using "Project JXTA", the first and only standardized set of open, generalized P2P protocols that allow arbitrary network devices to communicate and collaborate as peers. The JXTA protocols standardize the manner in which peers discover each other, self-organize into peer groups, advertise and discover network services, and securely communicate with and monitor each other-even across network firewalls. The key benefits include: Potential for dramatic improvements in science-data dissemination; Real-time-discoverable, potentially redundant (reliable), science-data services; Openness/Extensibility; Decentralized use of small, inexpensive, readily-available desktop machines; and Inherently secure-with ability to create variable levels of security by group.

  8. 基于移动对等网络的辅助教学模式的研究%Study on Mobile Peer-to-peer Networks Based Schema of Assistant Teaching

    Institute of Scientific and Technical Information of China (English)

    吴家皋

    2013-01-01

    随着计算机和无线移动网络通信技术的发展,关于移动学习的研究和应用越来越受到重视。针对现有集中服务模式的移动学习应用所存在的问题,开展基于移动对等网络的辅助教学模式的研究。从社会建构主义和人本主义教育思想的角度,分析了基于移动对等网络的辅助教学模式的基本特征;进而设计了一个基于移动对等网络的教学答疑应用实例,进一步阐明了该模式的合理性和可行性。%With the development of computer and wireless mobile network communication technology, research on mobile learning and its applications are obtained more and more attentions. Due to the problems of the existing mobile learning applica?tions of centralized service model, in the paper, the mobile peer-to-peer networks based schema of assistant teaching is studied. From the perspective of education thought of social constructivism and humanism, the characters of mobile peer-to-peer net?works based assistant teaching schema are analyzed. In addition, a mobile peer-to-peer network based Q&A teaching application is designed as an example to clarify the rationality and feasibility of the schema.

  9. Peer-to-Peer Service Sharing Platforms

    DEFF Research Database (Denmark)

    Andersson, Magnus; Hjalmarsson, Anders; Avital, Michel

    2013-01-01

    The sharing economy has been growing continuously in the last decade thanks to the proliferation of internet-based platforms that allow people to disintermediate the traditional commercial channels and to share excess resources and trade with one another effectively at a reasonably low transaction...... cost. Whereas early peer-to-peer platforms were designed to enable file sharing and goods trading, we recently witness the emergence of a new breed of peer-to-peer platforms that are designed for ordinary service sharing. Ordinary services entail intangible provisions and are defined as an economic...... activity that generates immaterial benefits and does not result in ownership of material goods. Based on a structured analysis of 41 internet-based rideshare platforms, we explore and layout the unique characteristics of peer-to-peer service sharing platforms based on three distinct temporal patterns...

  10. Peer-to-Peer Secure Multi-Party Numerical Computation

    CERN Document Server

    Bickson, Danny; Dolev, Danny; Pinkas, Benny

    2008-01-01

    We propose an efficient framework for enabling secure multi-party numerical computations in a Peer-to-Peer network. This problem arises in a range of applications such as collaborative filtering, distributed computation of trust and reputation, monitoring and numerous other tasks, where the computing nodes would like to preserve the privacy of their inputs while performing a joint computation of a certain function. Although there is a rich literature in the field of distributed systems security concerning secure multi-party computation, in practice it is hard to deploy those methods in very large scale Peer-to-Peer networks. In this work, we examine several possible approaches and discuss their feasibility. Among the possible approaches, we identify a single approach which is both scalable and theoretically secure. An additional novel contribution is that we show how to compute the neighborhood based collaborative filtering, a state-of-the-art collaborative filtering algorithm, winner of the Netflix progress ...

  11. A novel core-peer based trust model for peer-to-peer networks%点对点网络中核心节点结构的全局信任网络模型

    Institute of Scientific and Technical Information of China (English)

    李鹏; 魏登峰; 李敏

    2012-01-01

    In this paper,on account of the features of node trust relationships and smaller transaction possibilities in peer-to-peer network,a peer-to-peer trust network model is set forth based on its core nodes. Nodes in the network model are clustered according to their public reputation and private credibility. This paper discusses core nodes and ordinary nodes respectively relying on their node reliabilities and gives relevant solutions. The simulation results show that the trust model not only has robustness of anti-malicious node attacks but also has lower amount of assessment computation and communication overhead for network resources search.%针对点对点网络节点信任关系以及交易可能性较小的特点,阐述基于核心节点的点对点信任网络模型.该网络模型中的网络节点以公有度和私有信任度进行聚类,依靠节点可靠度针对核心节点和普通节点分情况讨论,并给予相关解决方案.仿真实验结果表明:该信任模型不但具有抗恶意节点攻击的鲁棒性,同时在网络资源搜索时具有较低的评估计算量和通信开销.

  12. A Dynamic Self-Adjusted Buffering Mechanism for Peer-to-Peer Real-Time Streaming

    Directory of Open Access Journals (Sweden)

    Jun-Li Kuo

    2011-05-01

    Full Text Available Multimedia live stream multicasting and on-line real-time applications are popular recently. Real-time multicast system can use peer-to-peer technology to keep stability and scalability without any additional support from the underneath network or a server. Our proposed scheme focuses on the mesh architecture of peer-to-peer live streaming system and experiments with the buffering mechanisms. We design the dynamic buffer to substitute the traditional fixed buffer.According to the existing measurements and our simulation results, using the traditional static buffer in a dynamic peer-to-peer environment has a limit of improving quality of service. In our proposed method, the buffering mechanism can adjust buffer to avoid the frozen or reboot of streaming based on the input data rate. A self-adjusted buffer control can be suitable for the violently dynamic peer-to-peer environment. Without any support of infrastructure and modification of peer-to-peer protocols, our proposed scheme can be workable in any chunk-based peer-to-peer streaming delivery. Hence, our proposed dynamic buffering mechanism varies the existing peer-to-peer live streaming system less to improve quality of experience more.

  13. Peer-to-Peer Cloud Provisioning: Service Discovery and Load-Balancing

    CERN Document Server

    Ranjan, Rajiv; Wu, Xiaomin; Liu, Anna

    2009-01-01

    This chapter presents: (i) a layered peer-to-peer Cloud provisioning architecture; (ii) a summary of the current state-of-the-art in Cloud provisioning with particular emphasis on service discovery and load-balancing; (iii) a classification of the existing peer-to-peer network management model with focus on extending the DHTs for indexing and managing complex provisioning information; and (iv) the design and implementation of novel, extensible software fabric (Cloud peer) that combines public/private clouds, overlay networking and structured peer-to-peer indexing techniques for supporting scalable and self-managing service discovery and load-balancing in Cloud computing environments. Finally, an experimental evaluation is presented that demonstrates the feasibility of building next generation Cloud provisioning systems based on peer-to-peer network management and information dissemination models. The experimental test-bed has been deployed on a public cloud computing platform, Amazon EC2, which demonstrates t...

  14. Survey on Anonymity in Unstructured Peer-to-Peer Systems

    Institute of Scientific and Technical Information of China (English)

    Ren-Yi Xiao

    2008-01-01

    Although anonymizing Peer-to-Peer (P2P) networks often means extra cost in terms of transfer efficiency, many systems try to mask the identities of their users for privacy consideration. By comparison and analysis of existing approaches,we investigate the properties of unstructured P2P anonymity, and summarize current attack models on these designs. Most of these approaches are path-based, which require peers to pre-construct anonymous paths before transmission, thus suffering significant overhead and poor reliability. We also discuss the open problems in this field and propose several future research directions.

  15. Digital portfolio og peer to peer feedback

    DEFF Research Database (Denmark)

    Jacobsen, Ditte; Bahrenscheer, Jesper Glarborg

    2017-01-01

    studerende og øget transfer mellem teori og praksis. Artiklen tager afsæt i erfaringerne fra udvikling, anvendelse og evaluering af den digitale portfolio og peer to peer feedback. Portfolien er digital og tilknyttet Metropols Learning Management System. De studerende uploader individuelt ugentligt deres......På Bioanalytikeruddannelsen på Professionshøjskolen Metropol har vi på ti-ugers modulet ”Molekylærbiologiske og genetiske analyser”, udviklet en digital portfolio som didaktisk redskab. Portfolien er blevet afprøvet på fire forløb, og har været med til at skabe større engagement blandt de...

  16. Distributed Stable-Group Differentiated Admission Control Algorithm in Mobile Peer-to-Peer Media Streaming System

    Institute of Scientific and Technical Information of China (English)

    XUEGuangtao; SHIHua; YOUJinyuan; YAOWensheng

    2003-01-01

    Mobile peer-to-peer media streaming systems are expected to become as popular as the peer-to-peer file sharing systems. In this paper, we study two key problems arising from mobile peer-to-peer media streaming: the stability of interconnection between supplying peers and requesting peers in mobile peer-to-peer streaming system; and fast capacity amplification of the entire mobile peer-to-peer streaming system. We use the Stable group algorithm to characterize user mobility in mobile ad hoc networks. Based on the stable group, we then propose a distributed Stable-group differentiated admission control algorithm (SGDACp2p), which leads to fast amplifying the system's total streaming capacity using its self-growing. At last, the extensive simulation results are presented to compare between the SGDACp2p and traditional methods to prove the superiority of the algorithm.

  17. Performance Evaluation of a Field Programmable Gate Array-Based System for Detecting and Tracking Peer-to-Peer Protocols on a Gigabit Ethernet Network

    Science.gov (United States)

    2010-06-01

    103 B.1.1 BRAM versus SDRAM Memory Scheme . . . . 103 B.1.2 DNS Packet Detection . . . . . . . . . . . . . . 105 B.1.3...22 LAN Local Area Network . . . . . . . . . . . . . . . . . . . . . 29 SPAN Switched Port Analyzer . . . . . . . . . . . . . . . . . . . 29 BRAM ...BitTorrent protocol was created by Bram Cohen as an alternative to the centralized file sharing programs such as Napster and Gnutella [Coh08]. The Napster file

  18. Resources searching method for unstructured peer-to-peer networks based on shortcuts between subtrees%基于子树间快捷连接的非结构化P2P资源搜索方法

    Institute of Scientific and Technical Information of China (English)

    吴晓军; 陈霁; 房佩; 郭海亮

    2012-01-01

    通过对非结构化P2P网络资源搜索方法的研究,提出了一种P2P覆盖网络.网络采用多路平衡树形拓扑结构,当新节点加入时在其与根节点的各子树间创建仅参与查询消息第一跳转发的快捷连接,搜索过程中利用快捷连接实现查询消息在根的各子树间并行转发并且不依赖根节点.仿真比较了所提网络同Gnutella和随机漫步网络的性能,所提网络具有低消息冗余率、高搜索成功率和较低的平均搜索时间复杂度.分析结果表明所提网络在资源搜索方面是高效可行的.%Through studying resources searching methods of unstructured Peer-to-Peer (P2P) network, a new P2P overlay network was proposed. Using a multi-way balanced tree topology, the network created shortcuts between the added node and each subtree of the root when a new node inserted, which forwarded first-hop of a query message only, and then query messages could be forwarded in parallel in each subtree of the root without relying on the root. Compared with the performance of Gnutella and Random Walks network in simulation, the proposed network had lower messages redundancy ratio, higher resource searching success ratio and lower average searching time complexity. The analytical results show that the proposed network is efficient and feasible for searching resources.

  19. Cloud resources locating algorithm based on peer-to-peer network%一种基于对等网络的云资源定位算法

    Institute of Scientific and Technical Information of China (English)

    李璞; 陈世平; 李剑锋

    2013-01-01

    This paper proposed a method that using distributed hash table (DHT) to generate a unique node ID for each cloud server. The ID represented the common identifier for the network topology,the retrieval information storage and query. At last built a structure P2P overlay network for distributed computing. This paper designed a new topology and routing protocol to solve the cloud resources' constant jump locating problem. Simulation results show the classic P2P algorithms' average search hops is positively correlated to the network size, and it cannot control the average search hops according to the actual needs of cloud computing. However the proposed algorithm' s average search hops has nothing to do with the network size, and it tends to the set value as the network size increases, therefore it can resolve the constant jump locating problem.%提出用分布式哈希表(DHT)为每台云服务器产生一个唯一的节点编号,该编号作为网络拓扑结构、检索信息存储和信息查询共同的标志符,从而形成一个适合分布式计算的结构化P2P覆盖网.设计了新的拓扑和路由协议来解决云资源的常数跳定位问题.仿真实验表明,经典的P2P算法平均查找跳数与网络规模成正相关,无法依据云计算的实际需要人为地控制查找跳数;该算法的平均查找跳数与网络规模无关,随着网络规模的增大而趋向于设定值,可以解决云资源的常数跳定位问题.

  20. Blog enabled peer-to-peer learning.

    Science.gov (United States)

    Hanson, Kami

    2011-01-01

    The purpose of this project was to simulate development of a community oral health plan using technology-based tools at the students' disposal. The specific research questions were: Will students use the Internet to identify community oral health issues and develop solutions to address the issues? Will blogs be a good tool to discuss and engage students in conversation with each other and to connect them with community oral health resources? How will blogging impact future academic and personal communications for the student? Dental hygiene students (n=30) participated in a community oral health course for 7 weeks. Students were asked to create a blog on which they would post weekly assignments and respond to 2 of their peer's blogs each week. Methods for data collection were post-treatment survey (15 items) analyzed for descriptive statistics and an analysis of written blog content according to a counting and coding scheme. Students used the Internet to identify issues and problem solving scenarios. Blogs were a good tool to engage students in discussions on oral health issues and peer-to-peer learning. Qualitative discourse analysis revealed evidence of critical thought and discourse throughout blog posts. Students referenced the Internet in blogs, while specific instances of resource sharing and provision of solutions to peers were less common. Students felt blogging encouraged them to engage with one another. Twenty percent of participating students have extended their use of blogging for both academic and personal purposes.

  1. Promoting Residential Renewable Energy via Peer-to-Peer Learning

    Science.gov (United States)

    Heiskanen, Eva; Nissilä, Heli; Tainio, Pasi

    2017-01-01

    Peer-to-peer learning is gaining increasing attention in nonformal community-based environmental education. This article evaluates a novel modification of a concept for peer-to-peer learning about residential energy solutions (Open Homes). We organized collective "Energy Walks" visiting several homes with novel energy solutions and…

  2. Introduction to the special section on peer-to-peer computing and web data management

    Institute of Scientific and Technical Information of China (English)

    Aoying ZHOU

    2008-01-01

    @@ Peer-to-peer (P2P) computing has been attracting attention from quite a few researchers and practitioners from different fields of computer science, such as networking, distributed computing, and database. Over P2P environment, the data management becomes a challenging issue.

  3. Peer-to-Peer Multimedia Sharing based on Social Norms

    CERN Document Server

    Zhang, Yu

    2011-01-01

    Empirical data shows that in the absence of incentives, a peer participating in a Peer-to-Peer (P2P) network wishes to free-riding. Most solutions for providing incentives in P2P networks are based on direct reciprocity, which are not appropriate for most P2P multimedia sharing networks due to the unique features exhibited by such networks: large populations of anonymous agents interacting infrequently, asymmetric interests of peers, network errors, and multiple concurrent transactions. In this paper, we design and rigorously analyze a new family of incentive protocols that utilizes indirect reciprocity which is based on the design of efficient social norms. In the proposed P2P protocols, the social norms consist of a social strategy, which represents the rule prescribing to the peers when they should or should not provide content to other peers, and a reputation scheme, which rewards or punishes peers depending on whether they comply or not with the social strategy. We first define the concept of a sustainab...

  4. P2P网络中搭便车行为分析与抑制机制建模%Analysis of Free-riding Behaviors and Modeling Restrain Mechanisms for Peer-to-Peer Networks

    Institute of Scientific and Technical Information of China (English)

    乐光学; 李仁发; 陈志; 周旭

    2011-01-01

    In a real peer-to-peer (P2P) network, large amounts of network measurement results show that free riding is prevalent in almost all P2P reliable streaming media networks, which reduces the robustness, availability, service response speed, and lifetime of P2P reliable streaming media networks. Research of the reasonable and effective mechanisms to prohibit free-riders and incite selfish nodes to contribute more to the system has become an important direction for application research of P2P reliable streaming media network. Analysis by the intrinsic characteristics of freeriding and the related impacts on system performance, the behaviors of P2P reliable streaming media nodes are modeled and an idea with the goal of keeping moderate safety by allowing some errors but no crimes is introduced without sacrificing overall performance. Furthermore, the game theory is used to restrain free-riders and encourage them to be more altruistic. Reputation, contribution, and revenue of each node are adopted as metrics to assess the model. And the existence of Nash equilibrium for the model is proved; the rules, constraints, and a detailed analysis of it are given as well. Simulations show that the proposed model is effective in countering free-riding behavior, improving the performance and quality of service (QoS) of the P2P reliable streaming media network. It is able to keep relative balance.%在现实网络中,节点日益严重的搭便车行为对P2P可信流媒体网络的健壮性、可用性、服务响应速度和生命周期等产生了重要的影响.设计合理且有效的搭便车行为抑制和鼓励自私节点为系统作贡献的策略已成为P2P可信流媒体系统应用研究的一个重要方向.在全面分析节点的搭便车行为机理和搭便车行为对网络性能影响的基础上,对节点在P2P可信流媒体网络中的行为建模,在保证网络性能的前提下引入"适度安全、容错不容罪"的思想以保持网络系

  5. Peer-to-Peer Topology Formation Using Random Walk

    Science.gov (United States)

    Kwong, Kin-Wah; Tsang, Danny H. K.

    Peer-to-Peer (P2P) systems such as live video streaming and content sharing are usually composed of a huge number of users with heterogeneous capacities. As a result, designing a distributed algorithm to form such a giant-scale topology in a heterogeneous environment is a challenging question because, on the one hand, the algorithm should exploit the heterogeneity of users' capacities to achieve load-balancing and, on the other hand, the overhead of the algorithm should be kept as low as possible. To meet such requirements, we introduce a very simple protocol for building heterogeneous unstructured P2P networks. The basic idea behind our protocol is to exploit a simple, distributed nature of random walk sampling to assist the peers in selecting their suitable neighbors in terms of capacity and connectivity to achieve load-balancing. To gain more insights into our proposed protocol, we also develop a detailed analysis to investigate our protocol under any heterogeneous P2P environment. The analytical results are validated by the simulations. The ultimate goal of this chapter is to stimulate further research to explore the fundamental issues in heterogeneous P2P networks.

  6. On the Degree Distribution of Faulty Peer-to-Peer Overlays

    CERN Document Server

    Ferretti, Stefano

    2011-01-01

    This paper presents an analytical framework to model fault-tolerance in unstructured peer-to-peer overlays, represented as complex networks. We define a distributed protocol peers execute for managing the overlay and reacting to node faults. Based on the protocol, evolution equations are defined and manipulated by resorting to generating functions. Obtained outcomes provide insights on the nodes' degree probability distribution. From the study of the degree distribution, it is possible to estimate other important metrics of the peer-to-peer overlay, such as the diameter of the network. We study different networks, characterized by three specific desired degree distributions, i.e. nets with nodes having a fixed desired degree, random graphs and scale-free networks. All these networks are assessed via the analytical tool and simulation as well. Results show that the approach can be factually employed to dynamically tune the average attachment rate at peers so that they maintain their own desired degree and, in ...

  7. The missing piece syndrome in peer-to-peer communication

    Directory of Open Access Journals (Sweden)

    Bruce Hajek

    2011-01-01

    Full Text Available Typical protocols for peer-to-peer file sharing over the Internet divide files to be shared into pieces. New peers strive to obtain a complete collection of pieces from other peers and from a seed. In this paper we investigate a problem that can occur if the seeding rate is not large enough. The problem is that, even if the statistics of the system are symmetric in the pieces, there can be symmetry breaking, with one piece becoming very rare. If peers depart after obtaining a complete collection, they can tend to leave before helping other peers receive the rare piece. Assuming that peers arrive with no pieces, there is a single seed, random peer contacts are made, random useful pieces are downloaded, and peers depart upon receiving the complete file, the system is stable if the seeding rate (in pieces per time unit is greater than the arrival rate, and is unstable if the seeding rate is less than the arrival rate. The result persists for any piece selection policy that selects from among useful pieces, such as rarest first, and it persists with the use of network coding.

  8. Is there something like a peer to peer science?

    Directory of Open Access Journals (Sweden)

    Michel Bauwens

    2010-03-01

    Full Text Available How will peer to peer infrastructures, and the underlying intersubjective and ethical relational model that is implied by it, affect scientific practice? Are peer-to-peer forms of cooperation, based on open and free input of voluntary contributors, participatory processes of governance, and universal availability of the output, more productive than centralized alternatives? In this short introduction, Michel Bauwens reviews a number of open and free, participatory and commons oriented practices that are emerging in scientific research and practice, but which ultimately point to a more profound epistemological revolution linked to increased participatory consciousness between the scientist and his human, organic and inorganic research material.

  9. Improved D-IDS using the federated peer-to-peer architecture

    Institute of Scientific and Technical Information of China (English)

    Hoan Kyu Lee; In Joo Jang; Hyeong Seon Yoo

    2007-01-01

    A number of IDSs have been proposed for a networked or distributed environment. A modified D-IDS using federated peer-to-peer architecture, MCR (Multicast Reflector) and modified shaker protocol were proposed. The suggested scheme can be implemented easily and performs the information sharing between low-level IDS agents. As all users within a group monitor each other's, the common control server can perform detect intrusions with less cost and support the detection of the inside intruders.

  10. Surfing Peer-to-Peer IPTV: Distributed Channel Switching

    Science.gov (United States)

    Kermarrec, A.-M.; Le Merrer, E.; Liu, Y.; Simon, G.

    It is now common for IPTV systems attracting millions of users to be based on a peer-to-peer (P2P) architecture. In such systems, each channel is typically associated with one P2P overlay network connecting the users. This significantly enhances the user experience by relieving the source from dealing with all connections. Yet, the joining process resulting in a peer to be integrated in channel overlay usually requires a significant amount of time. As a consequence, switching from one channel to another is far to be as fast as in IPTV solutions provided by telco operators. In this paper, we tackle the issue of efficient channel switching in P2P IPTV system. This is to the best of our knowledge the first study on this topic. First, we conducted and analyzed a set of measurements of one of the most popular P2P systems (PPlive). These measurements reveal that the set of contacts that a joining peer receives from the central server are of the utmost importance in the start-up process. On those neigbors, depends the speed to acquire the first video frames to play. We then formulate the switching problem, and propose a simple distributed algorithm, as an illustration of the concept, which aims at leveraging the presence of peers in the network to fasten the switch process. The principle is that each peer maintains as neighbors peers involved in other channels, providing peers with good contacts upon channel switching. Finally, simulations show that our approach leads to substantial improvements on the channel switching time. As our algorithmic solution does not have any prerequisite on the overlays, it appears to be an appealing add-on for existing P2P IPTV systems.

  11. Peer-to-Peer System Design: A Socioeconomic approach

    NARCIS (Netherlands)

    Rahman, R.

    2011-01-01

    It has gradually become clear that Peer-to-Peer (P2P) systems should not be conceived in the manner of conventional computing systems. Consequently, over the years, ideas from social science in general and economics in particular have made their way to P2P systems to deal with the novel challenges

  12. Peer-to-Peer System Design: A Socioeconomic approach

    NARCIS (Netherlands)

    Rahman, R.

    2011-01-01

    It has gradually become clear that Peer-to-Peer (P2P) systems should not be conceived in the manner of conventional computing systems. Consequently, over the years, ideas from social science in general and economics in particular have made their way to P2P systems to deal with the novel challenges t

  13. Computer-Mediated Peer-to-Peer Mentoring

    Science.gov (United States)

    Cavallaro, Francesco; Tan, Kenneth

    2006-01-01

    An online collaborative writing project was carried between two report writing classes from two separate institutions, Nanyang Technological University (NTU) and Singapore Polytechnic (SP). The aim was to test how successfully a peer-to-peer mentoring system could be established using asynchronous and synchronous communication features. The…

  14. Incentive Mechanisms for Peer-to-Peer Streaming

    Science.gov (United States)

    Pai, Vinay

    2011-01-01

    The increasing popularity of high-bandwidth Internet connections has enabled new applications like the online delivery of high-quality audio and video content. Conventional server-client approaches place the entire burden of delivery on the content provider's server, making these services expensive to provide. A peer-to-peer approach allows end…

  15. GPU peer-to-peer techniques applied to a cluster interconnect

    CERN Document Server

    Ammendola, Roberto; Biagioni, Andrea; Bisson, Mauro; Fatica, Massimiliano; Frezza, Ottorino; Cicero, Francesca Lo; Lonardo, Alessandro; Mastrostefano, Enrico; Paolucci, Pier Stanislao; Rossetti, Davide; Simula, Francesco; Tosoratto, Laura; Vicini, Piero

    2013-01-01

    Modern GPUs support special protocols to exchange data directly across the PCI Express bus. While these protocols could be used to reduce GPU data transmission times, basically by avoiding staging to host memory, they require specific hardware features which are not available on current generation network adapters. In this paper we describe the architectural modifications required to implement peer-to-peer access to NVIDIA Fermi- and Kepler-class GPUs on an FPGA-based cluster interconnect. Besides, the current software implementation, which integrates this feature by minimally extending the RDMA programming model, is discussed, as well as some issues raised while employing it in a higher level API like MPI. Finally, the current limits of the technique are studied by analyzing the performance improvements on low-level benchmarks and on two GPU-accelerated applications, showing when and how they seem to benefit from the GPU peer-to-peer method.

  16. Peer-to-peer computing in health-promoting voluntary organizations: a system design analysis.

    Science.gov (United States)

    Irestig, Magnus; Hallberg, Niklas; Eriksson, Henrik; Timpka, Toomas

    2005-10-01

    A large part of the health promotion in today's society is performed as peer-to-peer empowerment in voluntary organisations such as sports clubs, charities, and trade unions. In order to prevent work-related illness and long-term sickness absence, the aim of this study is to explore computer network services for empowerment of employees by peer-to-peer communication. The 'technique trade-off method was used for the analysis of the system design. A Critical Incident Technique questionnaire was distributed to a representative sample of trade union shop stewards (n = 386), and focus-group seminars were arranged where a preliminary set of requirements was discussed. Seven basic requirements were identified and matched to a set of 12 design issues for computer network services, allocating a subset of design issues to each requirement. The conclusion is that the systems design displays an inexpensive and potentially feasible method for peer-to-peer computing in voluntary health-promoting organisations.

  17. Peer-to-Peer Secure Multi-Party Numerical Computation Facing Malicious Adversaries

    CERN Document Server

    Bickson, Danny; Dolev, Danny; Pinkas, Benny

    2009-01-01

    We propose an efficient framework for enabling secure multi-party numerical computations in a Peer-to-Peer network. This problem arises in a range of applications such as collaborative filtering, distributed computation of trust and reputation, monitoring and other tasks, where the computing nodes is expected to preserve the privacy of their inputs while performing a joint computation of a certain function. Although there is a rich literature in the field of distributed systems security concerning secure multi-party computation, in practice it is hard to deploy those methods in very large scale Peer-to-Peer networks. In this work, we try to bridge the gap between theoretical algorithms in the security domain, and a practical Peer-to-Peer deployment. We consider two security models. The first is the semi-honest model where peers correctly follow the protocol, but try to reveal private information. We provide three possible schemes for secure multi-party numerical computation for this model and identify a singl...

  18. The future of mental health care: peer-to-peer support and social media.

    Science.gov (United States)

    Naslund, J A; Aschbrenner, K A; Marsch, L A; Bartels, S J

    2016-04-01

    about one's health condition. However, given the evidence to date, the benefits of online peer-to-peer support appear to outweigh the potential risks. Future research must explore these opportunities to support and empower people with serious mental illness through online peer networks while carefully considering potential risks that may arise from online peer-to-peer interactions. Efforts will also need to address methodological challenges in the form of evaluating interventions delivered through social media and collecting objective mental and physical health outcome measures online. A key challenge will be to determine whether skills learned from peers in online networks translate into tangible and meaningful improvements in recovery, employment, or mental and physical wellbeing in the offline world.

  19. The future of mental health care: peer-to-peer support and social media

    Science.gov (United States)

    Naslund, J. A.; Aschbrenner, K. A.; Marsch, L. A.; Bartels, S. J.

    2016-01-01

    feeling more uncertain about one’s health condition. However, given the evidence to date, the benefits of online peer-to-peer support appear to outweigh the potential risks. Conclusion Future research must explore these opportunities to support and empower people with serious mental illness through online peer networks while carefully considering potential risks that may arise from online peer-to-peer interactions. Efforts will also need to address methodological challenges in the form of evaluating interventions delivered through social media and collecting objective mental and physical health outcome measures online. A key challenge will be to determine whether skills learned from peers in online networks translate into tangible and meaningful improvements in recovery, employment, or mental and physical wellbeing in the offline world. PMID:26744309

  20. 对等网环境下基于树模型的对等节点的知识地图构建研究%Tree-based Construction Method on Knowledge Map for Peers on Peer-to-Peer Networks

    Institute of Scientific and Technical Information of China (English)

    秦春秀; 赵捧未; 李东; 孙蕾

    2013-01-01

    针对P2P网络知识资源共享中的资源无结构化和缺乏有效的资源导航问题,本文采用知识地图理论对对等网节点知识资源进行统一表示和导航,给出了对等节点的树形知识地图模型,该模型包含三个基本要素:知识单元集合、关系集合和关系集合到知识单元有序偶集合上的映射.在此基础上,以本体概念树为知识资源分类标准,给出了基于树形知识地图模型的对等网节点知识地图的构建方法.并邀请领域专家对树形知识地图的性能进行评价,评价结果表明本文构建的树形知识地图在对等节点知识资源结构化、导航方面具有不错的性能,为有效表示和导航对等网上的知识资源奠定初步的理论基础.%To solve the problems in unstructured database and lack of knowledge resources navigation on Peer-to-Peer networks, a tree-type knowledge map model is presented based on the theory of knowledge map, the model consists of three key elements; knowledge units set, relationships set and the mapping from a relationships set to a ordered pair in knowledge units. On the basis of the model, using a ontology concepts tree as the classification criteria, a method on the construction of knowledge map is proposed for peers on peer-to-peer networks. In addition, the evaluation results given by three experts points that the tree-based method on the construction of knowledge map for peers on peer-to-peer networks has a good performance in peers' knowledge resources representation and navigation.

  1. Study and Realization of Peer-to-peer Graph Routing in WirelessHART Network%无线HART网络点到点图路由的研究与实现

    Institute of Scientific and Technical Information of China (English)

    张茜; 秦雅娟; 朱昊清; 杨冬

    2014-01-01

    无线HART是一个开放的用于工业测量和控制的无线通信标准。无线HART标准在网络层采用图路由机制,通过提供链路冗余,以满足工业应用中安全、可靠的通信需求。现有的图路由算法研究仅局限于集中式通信,文中设计并实现了局部分布式通信的点到点图路由算法。该算法利用跳数、链路质量作为度量进行选路,提供跳间冗余以保证路由健壮性,并通过对跳间链路数的限定以及路由图范围的集中,可以为网络中任意两点间建立会话,减少控制时延,有效避免通信资源的浪费。该算法实现的通信模式不仅保留了集中式图路由的可靠性,也可以满足无线工业控制的灵活性和实时性需求。%WirelessHART is an open wireless communication protocol for industrial measurement and control. The graph routing protocol proposed by WirelessHART is meant to meet the requirements for reliable communications in industrial applications via providing link re-dundancies. Since algorithms on graph routing are mostly limited to the centralized communications at present,a peer-to-peer graph rou-ting algorithm is designed and implemented to realize sectional distributed communications in this paper. By measuring hops and link quality,the routing algorithm provides hop-by-hop multipath to ensure the routing robustness,and by limiting the number of links be-tween devices and the scale of the graph,communication resources can avoid being wasted. The communication pattern supported by this algorithm not only keeps the advantage of reliability provided by centralized graph routing,but also satisfies the requirements for flexibil-ity and real-time performance in wireless industrial control.

  2. SNAP: SNowbAll multi-tree Pushing for Peer-to-Peer Media Streaming

    CERN Document Server

    Luo, Jun

    2010-01-01

    Given the respective advantages of the two complimentary techniques for peer-to-peer media streaming (namely tree-based push and mesh-based pull), there is a strong trend of combining them into a hybrid streaming system. Backed by recently proposed mechanisms to identify stable peers, such a hybrid system usually consists of backbone trees formed by the stable peers and other overlay structures in the second tier to accommodate the remaining peers. In this paper, we embrace the hybrid push-pull structure for peer-to-peer media streaming. Our protocol is dominated by a multi-tree push mechanism to minimize the delay in the backbone and is complemented by other overlay structures to cope with peer dynamics. What mainly distinguishes our multi-tree pushing from the conventional ones is an unbalanced tree design guided by the so called snow-ball streaming, which has a provable minimum delay and can be smoothly "melded" with virtually any other existing overlay structures lying in the second tier. We design algori...

  3. A Survey on Security in Mobile Peer-to-Peer Architectures—Overlay-Based vs. Underlay-Based Approaches

    Directory of Open Access Journals (Sweden)

    Christian Gottron

    2010-10-01

    Full Text Available Mobile Ad hoc networks (MANET and Peer-to-Peer (P2P networks share central characteristics such as their distributed and decentralized nature. Combining both networking paradigms results in a Mobile Peer-to-Peer (MP2P system that operates independently from a preexisting infrastructure. Securing MP2P networks in terms of availability and robustness as basic demands in envisioned application scenarios like first responder operations is a challenging task. In this article, we present a survey of selected threats and of state of the art countermeasures for MANETs and P2P networks. Further, we discuss the efficiency of MANET and P2P security mechanisms when applied in MP2P networks.

  4. A comparison of peer-to-peer query response modes

    CERN Document Server

    Hoschek, W

    2002-01-01

    In a large distributed system spanning many administrative domains such as a Grid (Foster et al., 2001), it is desirable to maintain and query dynamic and timely information about active participants such as services, resources and user communities. However, in such a database system, the set of information tuples in the universe is partitioned over one or more distributed nodes, for reasons including autonomy, scalability, availability, performance and security. This suggests the use of peer-to-peer (P2P) query technology. A variety of query response modes can be used to return matching query results from P2P nodes to an originator. Although from the functional perspective all response modes are equivalent, no mode is optimal under all circumstances. Which query response modes allow to express suitable trade-offs for a wide range ofP2P application? We answer this question by systematically describing and characterizing four query response modes for the unified peer-to-peer database framework (UPDF) proposed ...

  5. Structured Query Translation in Peer to Peer Database Sharing Systems

    Directory of Open Access Journals (Sweden)

    Mehedi Masud

    2009-10-01

    Full Text Available This paper presents a query translation mechanism between heterogeneous peers in Peer to Peer Database Sharing Systems (PDSSs. A PDSS combines a database management system with P2P functionalities. The local databases on peers are called peer databases. In a PDSS, each peer chooses its own data model and schema and maintains data independently without any global coordinator. One of the problems in such a system is translating queries between peers, taking into account both the schema and data heterogeneity. Query translation is the problem of rewriting a query posed in terms of one peer schema to a query in terms of another peer schema. This paper proposes a query translation mechanism between peers where peers are acquainted in data sharing systems through data-level mappings for sharing data.

  6. A Peer-to-Peer Distributed Collaborative Optimization System

    Directory of Open Access Journals (Sweden)

    Caijun Xue

    2004-01-01

    Full Text Available It is difficult to solve design optimization problems of complex systems by using a traditional computing method because complex simulation processes usually lead to large-scale computation. Therefore the distributed computing technology based on decomposition-coordination theory has received much attention by design engineers. This paper studies a peer-to-peer collaborative optimization method based on distributed computing technology in order to examine flexible optimization. A new distributed collaborative optimization framework is proposed, and a coordination method is developed and used to deal with the conflict of related variables among sub-optimization problems. A multi-agent based distributed computing environment is implemented. The implementation of an optimization agent, in which CORBA technology is used to implement communication between the components of the optimization agent, is discussed in detail. Two examples are used to demonstrate the efficiency of the computing method and the reliability and flexibility of the multi-agent system.

  7. Peer-to-Peer Time-shifted Streaming Systems

    CERN Document Server

    Liu, Yaning

    2009-01-01

    In live streaming systems (IPTV, life-stream services, etc.), an attractive service consists in allowing users to access past portions of the stream. This is called a time-shifted streaming system. In our vision, a centralized time-shifted streaming system face scalability and ethical issues, therefore, we address the problem of designing a peer-to-peer system where peers store and deliver past chunks. We first attempt to identify the main characteristics of time-shifted streaming system from well-known measurements of VoD and IPTV systems. These overlays are the first structures specifically designed for time-shifted streaming system. Although no evaluation is presented, these preliminary description aim to foster discussions on a critical service.

  8. Cooperative peer-to-peer multiagent based systems

    CERN Document Server

    Caram, L F; Ausloos, M; Proto, A N

    2015-01-01

    A multiagent based model for a system of cooperative agents aiming at growth is proposed. This is based on a set of generalized Verhulst-Lotka-Volterra differential equations. In this study, strong cooperation is allowed among agents having similar sizes, and weak cooperation if agent have markedly different "sizes", thus establishing a peer-to-peer modulated interaction scheme. A rigorous analysis of the stable configurations is presented first examining the fixed points of the system, next determining their stability as a function of the model parameters. It is found that the agents are self-organizing into clusters. Furthermore, it is demonstrated that, depending on parameter values, multiple stable configurations can coexist. It occurs that only one of them always emerges with probability close to one, because its associated attractor dominates over the rest. This is shown through numerical integrations and simulations,after analytic developments. In contrast to the competitive case, agents are able to in...

  9. Secure Service Invocation in a Peer-to-Peer Environment Using JXTA-SOAP

    Science.gov (United States)

    Laghi, Maria Chiara; Amoretti, Michele; Conte, Gianni

    The effective convergence of service-oriented architectures (SOA) and peer-to-peer (P2P) is an urgent task, with many important applications ranging from e-business to ambient intelligence. A considerable standardization effort is being carried out from both SOA and P2P communities, but a complete platform for the development of secure, distributed applications is still missing. In this context, the result of our research and development activity is JXTA-SOAP, an official extension for JXTA enabling Web Service sharing in peer-to-peer networks. Recently we focused on security aspects, providing JXTA-SOAP with a general security management system, and specialized policies that target both J2SE and J2ME versions of the component. Among others, we implemented a policy based on Multimedia Internet KEYing (MIKEY), which can be used to create a key pair and all the required parameters for encryption and decryption of service messages in consumer and provider peers running on resource-constrained devices.

  10. A Log Auditing Approach for Trust Management in Peer-to-Peer Collaboration

    CERN Document Server

    Truong, Hien Thi Thu

    2010-01-01

    Nowadays we are faced with an increasing popularity of social software including wikis, blogs, micro-blogs and online social networks such as Facebook and MySpace. Unfortunately, the mostly used social services are centralized and personal information is stored at a single vendor. This results in potential privacy problems as users do not have much control over how their private data is disseminated. To overcome this limitation, some recent approaches envisioned replacing the single authority centralization of services by a peer-to-peer trust-based approach where users can decide with whom they want to share their private data. In this peer-to-peer collaboration it is very difficult to ensure that after data is shared with other peers, these peers will not misbehave and violate data privacy. In this paper we propose a mechanism that addresses the issue of data privacy violation due to data disclosure to malicious peers. In our approach trust values between users are adjusted according to their previous activi...

  11. Decentralised internet governance: the case of a ‘peer-to-peer cloud’

    Directory of Open Access Journals (Sweden)

    Francesca Musiani

    2014-02-01

    Full Text Available This article retraces the early stages of development of the 'peer-to-peer cloud' storage service Drizzle, with the aim of providing an example of decentralised network architecture as internet governance 'in practice'. More specifically, this paper sheds light on how changes in the architectural design of networked services affect the circulation, storage and privacy of data, as well as the rights and responsibilities exerted by different actors on them. This article does not mean to be a compendium of the implications of the decentralisation option in building a cloud platform, which entails a number of technical complications as well as advantages, including how to ensure the reliability and redundancy of data, and the soundness of the encryption mechanism. However, the privacy-related design choices described here are some of the many possible ways to illustrate the extent to which changes in network architecture are, indeed, changes in network governance.

  12. Beyond Music Sharing: An Evaluation of Peer-to-Peer Data Dissemination Techniques in Large Scientific Collaborations

    Energy Technology Data Exchange (ETDEWEB)

    Ripeanu, Matei [University of British Columbia, Vancouver; Al-Kiswany, Samer [University of British Columbia, Vancouver; Iamnitchi, Adriana [University of South Florida, Tampa; Vazhkudai, Sudharshan S [ORNL

    2009-03-01

    The avalanche of data from scientific instruments and the ensuing interest from geographically distributed users to analyze and interpret it accentuates the need for efficient data dissemination. A suitable data distribution scheme will find the delicate balance between conflicting requirements of minimizing transfer times, minimizing the impact on the network, and uniformly distributing load among participants. We identify several data distribution techniques, some successfully employed by today's peer-to-peer networks: staging, data partitioning, orthogonal bandwidth exploitation, and combinations of the above. We use simulations to explore the performance of these techniques in contexts similar to those used by today's data-centric scientific collaborations and derive several recommendations for efficient data dissemination. Our experimental results show that the peer-to-peer solutions that offer load balancing and good fault tolerance properties and have embedded participation incentives lead to unjustified costs in today's scientific data collaborations deployed on over-provisioned network cores. However, as user communities grow and these deployments scale, peer-to-peer data delivery mechanisms will likely outperform other techniques.

  13. Peer-to-Peer Live Streaming and Video On Demand Design Issues and its Challenges

    CERN Document Server

    K, Hareesh

    2011-01-01

    Peer-to-Peer Live streaming and Video on Demand is the most popular media applications over the Internet in recent years. These systems reduce the load on the server and provide a scalable content distribution. A new paradigm of P2P network collaborates to build large distributed video applications on existing networks .But, the problem of designing the system are at par with the P2P media streaming, live and Video on demand systems. Hence a comprehensive design comparison is needed to build such kind of system architecture. Therefore, in this paper we elaborately studied the traditional approaches for P2P streaming architectures, and its critical design issues, as well as practicable challenges. Thus, our studies in this paper clearly point the tangible design issues and its challenges, and other intangible issues for providing P2P VoD services.

  14. EOS: Evolutionary Overlay Service in Peer-to-Peer Systems

    Directory of Open Access Journals (Sweden)

    L. I. Zhijun

    2005-01-01

    Full Text Available The peer-to-peer (P2P systems nowadays can be mainly classified into two categories: structured and structure-less systems based on their overlay organization. The structured systems can achieve determinate efficiency due to their rigorous structure with the cost of losing robustness and vice versa. We provide a semi-structured overlay based on the separation of routing structures and overlay organizations in this paper and the new overlay can achieve determinate efficiency with high robustness. Moreover, the performance of the existing overlay is determined by the initial design and the overlay can not evolve with the information collected. But the new overlay devised in this paper is evolutionary inherent and accompanied by evolving service (EOS, EOS can improve the performance with the running of the P2P systems. Finally, our evolutionary overlay structure is constructed on the basis of linear algebra. So, the EOS can be theoretically analyzed and the results indicate that EOS can work with preferable integrated performance. The experimental results gained on the simulative platform verify the performance of EOS further.

  15. Cooperative peer-to-peer multiagent-based systems.

    Science.gov (United States)

    Caram, L F; Caiafa, C F; Ausloos, M; Proto, A N

    2015-08-01

    A multiagent based model for a system of cooperative agents aiming at growth is proposed. This is based on a set of generalized Verhulst-Lotka-Volterra differential equations. In this study, strong cooperation is allowed among agents having similar sizes, and weak cooperation if agents have markedly different "sizes", thus establishing a peer-to-peer modulated interaction scheme. A rigorous analysis of the stable configurations is presented first examining the fixed points of the system, next determining their stability as a function of the model parameters. It is found that the agents are self-organizing into clusters. Furthermore, it is demonstrated that, depending on parameter values, multiple stable configurations can coexist. It occurs that only one of them always emerges with probability close to one, because its associated attractor dominates over the rest. This is shown through numerical integrations and simulations, after analytic developments. In contrast to the competitive case, agents are able to increase their capacity beyond the no-interaction case limit. In other words, when some collaborative partnership among a relatively small number of partners takes place, all agents act in good faith prioritizing the common good, when receiving a mutual benefit allowing them to surpass their capacity.

  16. Inspiring peer-to-peer educations with film

    Science.gov (United States)

    Vachon, R. W.

    2014-12-01

    Oceans are vast, complicated, often inaccessible, three-dimensional and dark (for the most part). The value, vulnerabilities and dynamics of marine systems are quite far removed from the consciousness of many people. However, these reasons are not alibis for not understanding and appreciating oceans deep-rooted influences on our lives. Currently, the Nereus Program, a fellowship of climate, fisheries and computer modeling scientists, are accessing school systems in person and virtually, motivating teens to tell stories about their local understanding of the ocean's influence on their communities (even if they live in a landlocked location). In it's first iteration, we are soliciting youth to communicate through the popular medium of film. These films will be assembled into an on-line digital field guide. In part, this program is designed to be a peer-to-peer educational technique, where civilians are teaching other civilians about local or regional ocean dynamics. Additionally, the act of teaching through film is a proven method for deepening engagement, learning and empowerment of the individuals producing the films.

  17. Cooperative peer-to-peer multiagent-based systems

    Science.gov (United States)

    Caram, L. F.; Caiafa, C. F.; Ausloos, M.; Proto, A. N.

    2015-08-01

    A multiagent based model for a system of cooperative agents aiming at growth is proposed. This is based on a set of generalized Verhulst-Lotka-Volterra differential equations. In this study, strong cooperation is allowed among agents having similar sizes, and weak cooperation if agents have markedly different "sizes", thus establishing a peer-to-peer modulated interaction scheme. A rigorous analysis of the stable configurations is presented first examining the fixed points of the system, next determining their stability as a function of the model parameters. It is found that the agents are self-organizing into clusters. Furthermore, it is demonstrated that, depending on parameter values, multiple stable configurations can coexist. It occurs that only one of them always emerges with probability close to one, because its associated attractor dominates over the rest. This is shown through numerical integrations and simulations, after analytic developments. In contrast to the competitive case, agents are able to increase their capacity beyond the no-interaction case limit. In other words, when some collaborative partnership among a relatively small number of partners takes place, all agents act in good faith prioritizing the common good, when receiving a mutual benefit allowing them to surpass their capacity.

  18. Managing Supply and Demand of Bandwidth in Peer-to-Peer Communities

    NARCIS (Netherlands)

    Meulpolder, M.

    2011-01-01

    On today's Internet, millions of people participate in peer-to-peer communities where they share content such as audio and video files. Contrary to websites such as Youtube, which rely on large and expensive computer servers to store and deliver all of their content, peer-to-peer communities rely on

  19. Personalised Peer-Supported Learning: The Peer-to-Peer Learning Environment (P2PLE)

    Science.gov (United States)

    Corneli, Joseph; Mikroyannidis, Alexander

    2011-01-01

    The Peer-to-Peer Learning Environment (P2PLE) is a proposed approach to helping learners co-construct their learning environment using recommendations about people, content, and tools. The work draws on current research on PLEs, and participant observation at the Peer-to-Peer University (P2PU). We are particularly interested in ways of eliciting…

  20. P2P环境下信任社区的形成模型研究%Research on the Model of Community Formation Based on Trust in Peer - to - Peer Network

    Institute of Scientific and Technical Information of China (English)

    邢艳艳; 苏静

    2012-01-01

    P2P community is a set of nodes with similar interest, which can help to improve the efficiency of resource sharing and found. According to the characteristics of the different nodes in P2P network, community can not provide high resource sharing rate, a self - organized P2P community model is put forward based on trust. The main contribution of this paper is the trust establishment, trust value storage and trust value calculation. With the trust value changing and upda- ting, P2P network can show different community structures.%P2P社区是具有相似兴趣节点的集合,相似兴趣节点聚簇有助于提高资源共享和发现的效率。针对P2P网络中节点特性的差异,社区不一定都能够提供高资源共享率的问题,提出一种基于信任的自组织社区形成模型,从节点间信任的建立、信任值的存储、信任值的计算三个方面具体研究。随着节点问信息共享的频繁程度变化和节点间信任值的动态更新,P2P网络中能够呈现不同的社区结构。

  1. Peer-to-peer I/O (P2PIO) protocol specification Version 0.6

    Energy Technology Data Exchange (ETDEWEB)

    Berket, Karlo; Essiari, Abdelilah; Gunter, Dan; Hoschek, Wolfgang

    2004-04-21

    Today's distributed systems require simple and powerful resource discovery queries in a dynamic environment consisting of a large number of resources spanning many autonomous administrative domains. The distributed search problem is hard due to the variety of query types, the number of resources and their autonomous, partitioned and dynamic nature. We propose a generalized resource discovery framework that is built around an application level messaging protocol called Peer-to-Peer I/O (P2PIO). P2PIO addresses a number of scalability problems in a general way. It provides flexible and uniform transport-independent resource discovery mechanisms to reduce both the client and network burden in multi-hop P2P systems.

  2. Rate-distortion optimized bitstream switching for peer-to-peer live streaming

    Institute of Scientific and Technical Information of China (English)

    Jin-feng ZHANG; Rong-gang WANG; Jian-wei NIU; Yuan DONG; Hai-la WANG

    2008-01-01

    Peer-to-peer (P2P) technology provides a cost-effective and scalable way to distribute video data. However, high heterogeneity of the P2P network, which rises not only from heterogeneous link capacity between peers hut also from dynamic variation of available bandwidth, brings forward great challenge to video streaming. To attack this problem, an adaptive scheme based on rate-distortion optimization (RDO) is proposed in this paper. While low complexity RDO based frame dropping is exploited to shape bitrate into available bandwidth in peers, the streamed bitstream is dynamically switched among multiple available versions in an RDO way by the streaming server. Simulation results show that the proposed scheme based on RDO achieves great gain in overall perceived quality over simple heuristic schemes.

  3. Virtual University: A Peer to Peer Open Education Network

    Science.gov (United States)

    Razavi, Amir R.; Strommen-Bakhtiar, Abbas; Krause, Paul

    2011-01-01

    The world is currently going through a transitional period, moving from the Service era to the Information era. Rapid societal and technological innovations are changing the way we live, communicate, and work. As the rate of the technological/societal change increases, pressure on educational institutions also increases. This pressure is…

  4. PADMINI: A PEER-TO-PEER DISTRIBUTED ASTRONOMY DATA MINING SYSTEM AND A CASE STUDY

    Data.gov (United States)

    National Aeronautics and Space Administration — PADMINI: A PEER-TO-PEER DISTRIBUTED ASTRONOMY DATA MINING SYSTEM AND A CASE STUDY TUSHAR MAHULE*, KIRK BORNE, SANDIPAN DEY*, SUGANDHA ARORA, AND HILLOL KARGUPTA...

  5. Distributed Decision-Tree Induction in Peer-to-Peer Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper offers a scalable and robust distributed algorithm for decision-tree induction in large peer-to-peer (P2P) environments. Computing a decision tree in such...

  6. Study of Reputation Based Defense Mechanism in Peer To Peer Live Streaming

    Directory of Open Access Journals (Sweden)

    M. A. Mottalib

    2011-11-01

    Full Text Available Peer-to-peer live video streaming systems are having more popularity as the information technology is advancing fast. Peer-to-peer live video streaming systems are like peer-to-peer file sharing system and they are also vulnerable to content pollution attack as file sharing. In this type of attack, the attacker mixes polluted or unnecessary data into the streaming data and forwards the polluted data to normal peers and hence the perceived video quality is decreased. In this paper, a comparative study is conducted among three defense mechanisms against pollution attack in peer-to-peer live streaming systems: Blacklisting, Simple Decentralized Reputation System and Bayesian Approach to Reputation System. Finally performance analysis and the derived result has been presented.

  7. Client-side Web Mining for Community Formation in Peer-to-Peer Environments

    Data.gov (United States)

    National Aeronautics and Space Administration — In this paper we present a framework for forming interests-based Peer-to-Peer communities using client-side web browsing history. At the heart of this framework is...

  8. IMPLEMENTATION OF REPUTATION EXCHANGE PROTOCOL IN PEER-TO-PEER SYSTEM

    Directory of Open Access Journals (Sweden)

    B.Udhaya,

    2011-03-01

    Full Text Available The motivation behind basing applications on peer-to-peer architectures derives to a large extent from their ability to function, scale and self-organize in the presence of a highly transient population of nodes, network and computer failures, without the need of a central server and the overhead of its administration. P2P networks are vulnerable to peers, who cheat, propagate malicious codes, or peers who do not cooperate. Traditional client-server security models are not sufficient to P2P networks because of their centralized nature. Absence of central authority in P2P poses unique challenges like identity management of the peers, secure reputation data management and Sybil attack for reputation management in the network. In this paper we present a cryptographic protocol for ensuring secure and timely availability of the reputation data of a peer extremely at low cost. The past behavior of the peer is encapsulated in its digital reputation and is subsequently used to predict the future actions. The cryptographic protocol is coupled with self-certification and cryptographic mechanisms for identitymanagement and countering Sybil attacks. The latency associated with a file replication in a P2P system consists of two components: the query search time and the time required by the peers to transmit the file. In order to model the peer level latency, we develop a queuing model to evaluate the time required at each peer to serve its replication requests.

  9. Data Management in Peer-to-Peer Environment:A Perspective of BestPeer

    Institute of Scientific and Technical Information of China (English)

    ZHOU AoYing(周傲英); QIAN WeiNing(钱卫宁); ZHOU ShuiGeng(周水庚); LING Bo(凌波); XU LinHao(徐林昊); Ng Wee Siong(黄维雄); Ooi Beng Chin(黄铭钧); Tan Kian-Lee(陈建利)

    2003-01-01

    Peer-to-Peer (P2P) systems have attracted much attention in academic community and industry circles due to their promising applications in various domains. This paper presents the authors' research efforts on introducing complex query capabilities in a P2P environment consisting of numerous peers with large volume of data. An underlying hybrid P2P computing platform, named BestPeer is described first. The connection among peers within BestPeer is selfconfigurable through maintaining the nearest neighbor of peers, and the agent techniques employed in the system ensure its capability of providing sophisticated services. The designs of three P2P data management systems which are all based on BestPeer are described in detail. They provide support for information retrieval, query processing and Web services respectively. Advantages and limitations are discussed, while ongoing work is presented. Current systems can provide basic functions for keyword-based search, SQL-like query processing, and Web services querying and discovery. Some further topics on providing fully-fledged data management functionalities for P2P distributed computing systems with security guarantee are also discussed.

  10. Multi-Data Source Fusion Approach in Peer-To-Peer Systems

    Directory of Open Access Journals (Sweden)

    Gilles Nachouki

    2010-02-01

    Full Text Available In this paper, a new approach for data fusion in the context of schema-basedPeer-To-Peer (P2P systems is proposed. Schema-based systems manage andprovide query capabilities for (semi-structured information: queries have to beformulated in terms of schema. Schema-based P2P are called Peer DataManagement system (PDMS. A challenging problem in a schema-based peerto-peer (P2P system is how to locate peers who have data relevant to a givenquery.Our proposal lies in application of the multi-data source fusion approach in thecontext of PDMS. Multi-data source schemas, distributed, shared andmaintained by peers, are the basis of a semantic overlay network. The semanticoverlay network and the power of Multi-data source Fusion Language (MFLare exploited for efficient query routing towards the relevant peers. We showthe design of the Peer Multi-Data source Management System (PMDMS andwe focus on the Matchmaker and routing components. We give a performanceevaluation of the semantic query routing with respect to important criteria suchas precision, recall, response time and number of messages. We give aperformance evaluation of the semantic reconciliation between peers. Wecompare this result with other systems developed according to peer/super-peerapproach. Finally, we show a prototype developed according to PMDMS. Webuild an application that shares, data between peers, in the domain of leisuresuch as, bank, cinema, restaurant, etc.

  11. Data Sharing in a File Structured QoS Aware Peer-To-Peer System

    Directory of Open Access Journals (Sweden)

    A. Samydurai

    2014-05-01

    Full Text Available The Peer-to-Peer system has the potential capacity in building an efficient unified network structure for location based secure data transfer with information sharing and minimizing the failure factor. In this study we define the data transfer with certain futuristic characters that will provide data sharing strength for the users to understand the efficiency with which the data reaches the end node or users. For this purpose we have used specific QoS metric tools like, bandwidth, lookup time, delay, response time and trip time that will help in data sharing. This study concentrates on the search operation on the P2P network for data retrieval. Replication strategy is used in order to increase the probability of successful search. The lookup search employed in this regard uses two type of search namely ring and binary search. The efficiency aspect of data transfer in this study raises the importance of the system compared with the earlier system. The performance analysis will clearly chat out the quality of this system of data sharing and searching. Evaluations have shown a positive sign in the functioning of the proposed system.

  12. Redundancy Maintenance and Garbage Collection Strategies in Peer-to-Peer Storage Systems

    Science.gov (United States)

    Liu, Xin; Datta, Anwitaman

    Maintaining redundancy in P2P storage systems is essential for reliability guarantees. Numerous P2P storage system maintenance algorithms have been proposed in the last years, each supposedly improving upon the previous approaches. We perform a systematic comparative study of the various strategies taking also into account the influence of different garbage collection mechanisms, an issue not studied so far. Our experiments show that while some strategies generally perform better than some others, there is no universally best strategy, and their relative superiority depends on various other design choices as well as the specific evaluation criterion. Our results can be used by P2P storage systems designers to make prudent design decisions, and our exploration of the various evaluation metrics also provides a more comprehensive framework to compare algorithms for P2P storage systems. While there are numerous network simulators specifically developed even to simulate peer-to-peer networks, there existed no P2P storage simulators - a byproduct of this work is a generic modular P2P storage system simulator which we provide as open-source. Different redundancy, maintenance, placement, garbage-collection policies, churn scenarios can be easily integrated to the simulator to try out new schemes in future, and provides a common framework to compare (future) p2p storage systems designs - something which has not been possible so far.

  13. Fundamental delay bounds in peer-to-peer chunk-based real-time streaming systems

    CERN Document Server

    Bianchi, Giuseppe; Bracciale, Lorenzo; Piccolo, Francesca Lo; Salsano, Stefano

    2009-01-01

    This paper addresses the following foundational question: what is the maximum theoretical delay performance achievable by an overlay peer-to-peer streaming system where the streamed content is subdivided into chunks? As shown in this paper, when posed for chunk-based systems, and as a consequence of the store-and-forward way in which chunks are delivered across the network, this question has a fundamentally different answer with respect to the case of systems where the streamed content is distributed through one or more flows (sub-streams). To circumvent the complexity emerging when directly dealing with delay, we express performance in term of a convenient metric, called "stream diffusion metric". We show that it is directly related to the end-to-end minimum delay achievable in a P2P streaming network. In an homogeneous scenario, we derive a performance bound for such metric, and we show how this bound relates to two fundamental parameters: the upload bandwidth available at each node, and the number of neigh...

  14. Peer-to-peer Monte Carlo simulation of photon migration in topical applications of biomedical optics

    Science.gov (United States)

    Doronin, Alexander; Meglinski, Igor

    2012-09-01

    In the framework of further development of the unified approach of photon migration in complex turbid media, such as biological tissues we present a peer-to-peer (P2P) Monte Carlo (MC) code. The object-oriented programming is used for generalization of MC model for multipurpose use in various applications of biomedical optics. The online user interface providing multiuser access is developed using modern web technologies, such as Microsoft Silverlight, ASP.NET. The emerging P2P network utilizing computers with different types of compute unified device architecture-capable graphics processing units (GPUs) is applied for acceleration and to overcome the limitations, imposed by multiuser access in the online MC computational tool. The developed P2P MC was validated by comparing the results of simulation of diffuse reflectance and fluence rate distribution for semi-infinite scattering medium with known analytical results, results of adding-doubling method, and with other GPU-based MC techniques developed in the past. The best speedup of processing multiuser requests in a range of 4 to 35 s was achieved using single-precision computing, and the double-precision computing for floating-point arithmetic operations provides higher accuracy.

  15. Aorta: a management layer for mobile peer-to-peer massive multiplayer games

    Science.gov (United States)

    Edlich, Stefan; Hoerning, Henrik; Brunnert, Andreas; Hoerning, Reidar

    2005-03-01

    The development of massive multiplayer games (MMPGs) for personal computers is based on a wide range of frameworks and technologies. In contrast, MMPG development for cell phones lacks the availability of framework support. We present Aorta as a multi-purpose lightweight MIDP 2.0 framework to support the transparent and equal API usage of peer-to-peer communication via http, IP and Bluetooth. Special experiments, such as load-tests on Nokia 6600s, have been carried out with Bluetooth support in using a server-as-client architecture to create ad-hoc networks by using piconet functionalities. Additionally, scatternet functionalities, which will be supported in upcoming devices, have been tested in a simulated environment on more than 12 cell phones. The core of the Aorta framework is the Etherlobby, which manages connections, peers, the game lobby, game policies and much more. The framework itself was developed to enable the fast development of mobile games, regardless of the distance between users, which might be within the schoolyard or much further away. The earliest market-ready application shown here is a multimedia game for cell phones utilizing all of the frameworks features. This game, called Micromonster, acts as platform for developer tests, as well as providing valuable information about interface usability and user acceptance.

  16. Towards the On-line Identification of Peer-to-peer Flow Patterns

    Directory of Open Access Journals (Sweden)

    Antonio Nogueira

    2009-04-01

    Full Text Available The number and variety of IP applications have hugely increased in the last few years. Among them, peer-to-peer (P2P file-sharing applications have become very popular: more users are continuously joining such systems and more objects are being made available, seducing even more users to join. An accurate mapping of traffic to applications is important for a wide range of network management tasks. Besides, traditional mapping approaches have become increasingly inaccurate because many applications use non-default or ephemeral port numbers, use well-known port numbers associated with other applications, change application signatures or use traffic encryption. This paper proposes a framework to identify Internet applications that can be mainly used in situations where existing identification frameworks are not efficient or can not be used at all. The core block of the identification tool is based on neural networks and is able to identify different flow patterns generated by various Internet applications. Neural network based identification relies on a previous identification of the different IP applications that can be obtained offline using any reliable method. In this way, the paper also presents a module to process IP traffic flows and identify the underlying applications using payload analysis techniques. The identification results obtained from this tool are used in the training phase of the neural network identification framework. The accuracy of the identification framework was evaluated by performing a set of intensive tests and the results obtained show that, when conveniently trained, neural networks constitute a valuable tool to identify Internet applications while being, at the same time, immune to the most important disadvantages presented by other identification methods.

  17. Peer-to-peer interprofessional health policy education for Medicare part D.

    Science.gov (United States)

    Lipton, Helene L; Lai, Cindy J; Cutler, Timothy W; Smith, Amanda R; Stebbins, Marilyn R

    2010-08-10

    To determine whether a peer-to-peer education program was an expedient and effective approach to improve knowledge and promote interprofessional communication and collaboration. Trained pharmacy students taught nursing students, medical students, and medical residents about the Medicare Part D prescription drug benefit (Part D), in 1- to 2-hour lectures. Learners completed a survey instrument to assess the effectiveness of the presentation and their attitudes toward the peer-to-peer instructional format. Learners strongly or somewhat agreed that the peer-to-peer format was effective in providing Part D education (99%) and promoted interprofessional collaboration (100%). Qualitative data highlighted the program's clinical relevance, value in promoting interprofessional collaboration, and influence on changing views about the roles and contributions of pharmacists. The Part D peer educator program is an innovative way to disseminate contemporary health policy information rapidly, while fostering interprofessional collaboration.

  18. An ID-Based Authenticated Key Agreement Protocol for Peer-to-Peer Computing

    Institute of Scientific and Technical Information of China (English)

    LU Rong-xing; CAO Zhen-fu; SU Ren-wang; CHAI Zhen-chuan

    2006-01-01

    Peer-to-peer computing has recently started to gain significant acceptance, since it can greatly increase the performance and reliability of overall system. However, the security issue is still a major gating factor for its full adoption. In order to guarantee the security of data exchanged between two peers in Peer-to-Peer system, this paper comes up with an ID-based authenticated key agreement from bilinear pairings and uses BAN logic to prove the protocol's security. Compared with other existing protocols, the proposed protocol seems more secure and efficient, since it adopts the static shared Diffie-Hellman key.

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

    Directory of Open Access Journals (Sweden)

    Arockia Xavier Annie. Rayan

    2012-10-01

    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: http://www.ijcaonline.org/archives/volume36/number1/4455-6238

  20. On Democracy in Peer-to-Peer systems

    CERN Document Server

    Baraglia, Ranieri; Mordacchini, Matteo; Ricci, Laura; Alessi, Luca

    2011-01-01

    The information flow inside a P2P network is highly dependent on the network structure. In order to ease the diffusion of relevant data toward interested peers, many P2P protocols gather similar nodes by putting them in direct contact. With this approach the similarity between nodes is computed in a point-to-point fashion: each peer individually identifies the nodes that share similar interests with it. This leads to the creation of a sort of "private" communities, limited to each peer neighbors list. This "private" knowledge do not allow to identify the features needed to discover and characterize the correlations that collect similar peers in broader groups. In order to let these correlations to emerge, the collective knowledge of peers must be exploited. One common problem to overcome in order to avoid the "private" vision of the network, is related to how distributively determine the representation of a community and how nodes may decide to belong to it. We propose to use a gossip-like approach in order t...

  1. Adaptive peer-to-peer streaming with MutualCast

    Institute of Scientific and Technical Information of China (English)

    HUANG Cheng; CHOU Philip A.; LI Jin; ZHANG Cha

    2006-01-01

    Application Layer Multicast (ALM) can greatly reduce the load of a server by leveraging the outgoing bandwidth of the participating nodes. However, most proposed ALM schemes become quite complicated and lose bandwidth efficiency if they try to deal with networks that are significantly heterogeneous or time-varying. In earlier work, we proposed MutualCast, an ALM scheme with fully connected mesh that quickly adapts to the time-varying networks, while achieving provably optimal throughput performance. In this paper, we study how MutualCast can be paired with adaptive rate control for streaming media. Specifically,we combine Optimal Rate Control (ORC), our earlier control-theoretical framework for quality adaptation, with the MutualCast delivery scheme. Using multiple bit rate video content, we show that the proposed system can gracefully adjust the common quality received at all the nodes while maintaining a continuous streaming experience at each, even when the network undergoes severe, uncorrelated bandwidth fluctuations at different peer nodes.

  2. Care pathways in thrombosis management: the INNOVATE peer-to-peer educational initiative

    Science.gov (United States)

    Patel, Raj K

    2017-01-01

    Context Anticoagulant options for the management of venous thromboembolism (VTE) now include the non-vitamin K antagonist oral anticoagulants (NOACs). The safe and effective integration of these agents into routine clinical practice within different health care settings presents common challenges. Bayer AG created the INternational Network fOr Venous and Arterial Thrombosis Excellence in practice (INNOVATE) program as a professional education network to foster best practice in thrombosis management in the NOAC era. Concept and format Since 2013, INNOVATE has been run as a series of educational 1.5-day global meetings at VTE centers of excellence. The format is based on expert-led discussion rather than lectures; all participants are encouraged to share their own expertise and experience. Through peer-to-peer exchange, less experienced professionals from an array of specialties learn from others in a small-group interactive setting. This format encourages positive engagement and discussion, and the establishment of relationships between health care professionals from different countries. Expansion and localization INNOVATE has successfully expanded to cover a broad spectrum of thromboembolic disorders in which anticoagulation with NOACs plays an important role; now including specific meetings focusing on the management of patients in the community. Local meetings are run in many countries in the local language, facilitating discussion and ensuring applicability to local or regional issues. Implementing learnings INNOVATE delegates have provided consistently positive feedback and have used their attendance to create and improve thrombosis management pathways in their own institutions. Overseen by a Steering Committee, the program responds to feedback, evolving to meet the needs of participants. Conclusion By showcasing best practice in the care of patients requiring anticoagulation, INNOVATE provides a model for the non-promotional support of medical education by

  3. Blogging as an Innovative Method of Peer-to-Peer Educational Sharing.

    Science.gov (United States)

    Nedder, Melanie M; Levine, Sharon A; Galligan, Caroline; Avery, Kathleen Ryan; Eagan-Bengston, Elizabeth; Reilly, Karen M

    2017-02-01

    Nurses in the cardiac intensive care unit often attend professional education opportunities. However, it is difficult to share this information among nursing staff. Varying schedules, different shifts, and patient acuity limit the amount of time available for peer-to-peer sharing of educational information. A review of the literature revealed scant research on blogging for peer-to-peer education in general and particularly in nursing. To explore nurses' perception of the effectiveness of using a blog as a forum to provide peer-to-peer sharing of relevant professional education. Using a simple, free blogging website, the unit's nursing practice council developed a private blog for educational information sharing among the nursing staff. An online survey was administered to the unit's staff 15 months after the blog was implemented. Most respondents indicated that they thought the blog is an effective way to share professional education (86%), keeps them abreast of evidence-based practice (81%), and has led to practice change (59%). Nearly 80% of respondents agreed that they are more likely to attend professional conferences, and 62% would consider contributing blog posts. The survey results suggest that blogging may be an effective method of peer-to-peer sharing of education, although more rigorous research is required in this area. ©2017 American Association of Critical-Care Nurses.

  4. Agent-oriented Modeling for Collaborative Learning Environments: A Peer-to-Peer Helpdesk Case Study

    NARCIS (Netherlands)

    Guizzardi-Silva Souza, R.; Wagner, G.; Aroyo, L.M.

    2002-01-01

    In this paper, we present the analysis and modelling of Help&Learn, an agent-based peer-to-peer helpdesk system to support extra-class interactions among students and teachers. Help&Learn expands the student’s possibility of solving problems, getting involved in a cooperative learning experience tha

  5. Applying Peer-to-Peer Technology to the Building of Distributed Educational Systems

    Science.gov (United States)

    Leighton, Greg; Muldner, Tomasz

    2005-01-01

    Existing educational systems built for cooperative and collaborative activities are most often based on the client/server paradigm of distributed computing. This article shows that a new model for distributed computing, Peer-to-Peer (P2P), provides new opportunities for building distributed educational applications. It begins by reviewing general…

  6. Telemedicine for Peer-to-Peer Psychiatry Learning between U.K. and Somaliland Medical Students

    Science.gov (United States)

    Keynejad, Roxanne; Ali, Faisal R.; Finlayson, Alexander E. T.; Handuleh, Jibriil; Adam, Gudon; Bowen, Jordan S. T.; Leather, Andrew; Little, Simon J.; Whitwell, Susannah

    2013-01-01

    Objective: The proportion of U.K. medical students applying for psychiatry training continues to decline, whereas, in Somaliland, there are no public-sector psychiatrists. This pilot study assessed the usefulness and feasibility of online, instant messenger, peer-to-peer exchange for psychiatry education between cultures. Method: Twenty medical…

  7. Messaging, Gaming, Peer-to-Peer Sharing: Language Learning Strategies & Tools for the Millennial Generation

    Science.gov (United States)

    Godwin-Jones, Bob

    2005-01-01

    The next generation's enthusiasm for instant messaging, videogames, and peer-to-peer file swapping is likely to be dismissed by their elders as so many ways to waste time and avoid the real worlds of work or school. But these activities may not be quite as vapid as they may seem from the perspective of outsiders--or educators. Researchers point…

  8. DServO: A Peer-to-Peer-based Approach to Biomedical Ontology Repositories.

    Science.gov (United States)

    Mambone, Zakaria; Savadogo, Mahamadi; Some, Borlli Michel Jonas; Diallo, Gayo

    2015-01-01

    We present in this poster an extension of the ServO ontology server system, which adopts a decentralized Peer-To-Peer approach for managing multiple heterogeneous knowledge organization systems. It relies on the use of the JXTA protocol coupled with information retrieval techniques to provide a decentralized infrastructure for managing multiples instances of Ontology Repositories.

  9. A Peer-to-Peer Health Education Program for Vulnerable Children in Uganda

    Science.gov (United States)

    Falk, Diane S.; Pettet, Kristen; Mpagi, Charles

    2016-01-01

    In this paper, children attending a U.S.-sponsored private primary school serving orphaned and vulnerable children in Uganda were interviewed in focus groups about their participation in a peer-to-peer health education program in which they used music, dance, poetry, art, and drama to convey health information. The children reported enhanced…

  10. Security Visualization for peer-to-peer resource sharing applications

    CERN Document Server

    Tri, Dand Tran

    2009-01-01

    Security of an information system is only as strong as its weakest element. Popular elements of such system include hardware, software, network and people. Current approaches to computer security problems usually exclude people in their studies even though it is an integral part of these systems. To fill that gap, this paper discusses crucial people-related problems in computer security and proposes a method of improving security in such systems by integrating people tightly into the whole system. The integration is implemented via visualization to provide visual feedbacks and capture people's awareness of their actions and consequent results. By doing it, we can improve system usability, shorten user's learning curve, and hence enable user uses computer systems more securely.

  11. Discourage free riding in Peer-to-Peer file sharing systems with file migration and workload balancing approach

    Institute of Scientific and Technical Information of China (English)

    YU Yijiao; JIN Hai

    2007-01-01

    Free riding is a great challenge to the development and maintenance of Peer-to-Peer(P2P)networks.A file migration and workload balancing based approach (FMWBBA)to discourage free riding is proposed in this paper.The heart of our mechanism is to migrate some shared files from the overloaded peers to the neighboring free riders automatically and transparently,which enforces free riders to offer services when altruistic peers are heavily overloaded.File migration is a key issue in our approach,and some related strategies are discussed.A simulation is designed to verify this approach,and the results show that it can not only alleviate free riding,but also improve the Quality of Service(QoS)and robustness of P2P networks efficiently.

  12. Peer-to-Peer content distribution using automatically recombined fingerprints

    Directory of Open Access Journals (Sweden)

    J.Murugeswari,

    2015-11-01

    Full Text Available Due to the recent advances in broad-band network and multimedia technologies, the distribution of multimedia contents are increasing. This will help a malicious party to duplicate and redistribute the contents; hence the protection of the ownership is required in multimedia content distribution. The encryption of content cannot solve the issue, because it must be ultimately decrypted at genuine users who have legal authority to distribute content. Therefore, additional protection mechanisms are needed to discourage unauthorized redistribution. One of the mechanisms is to generate the fingerprinting of multimedia which enables a seller to trace illegal users by embedding identification information into the content. The research on fingerprinting techniques is classified into two studies: collusion resistant fingerprinting systems and cryptographic protocol. Since each user download content with his/her own fingerprint and content is a little different. If users collect some of them, they try to find the difference and modify/delete the embedded information. Unicast transmission is applied in multimedia content distribution which will be give more security to buyers. Merchant will create number of seed buyers who need to distribute the content to child buyers. All the seed buyers should be online to distribute the content. The seed buyer and child buyer fingerprint are need to store in database which will be required to find the illegal redistribution.

  13. Head-Tail Video Streaming Over Peer To Peer Systems

    Directory of Open Access Journals (Sweden)

    Ali Sianati

    2011-03-01

    Full Text Available P2P systems similar to file sharing applications are being used vastly due to unrestricted nature of thesesystems. Their unrestricting comes from their ability to cooperate and aggregate peer’s resources andtheir scalability. On the other side, today technologies are traditional client-server applications. Theseapplications can perform strongly but they are not scalable due to limitations on server resources. Thislimitation of the client/server technology leads designers to use alternative technologies mainly P2P. Asa streaming system, P2P streaming network can be formed into two types, Tree-based and Mesh-based.In this paper a new mesh-based P2P system named Head-Tail streaming is proposed. Head-Tailsimplifies packet scheduling and node failure recovery by using paired-peer sending and node failureprediction. Our system outperforms ordinary systems comparing as delay and receive time. Our systemperforms better than ordinary systems based on two reasons :Overlapping sequence of chunks and nodereplacement policy.

  14. Writing to Learn and Learning to Write across the Disciplines: Peer-to-Peer Writing in Introductory-Level MOOCs

    Science.gov (United States)

    Comer, Denise K.; Clark, Charlotte R.; Canelas, Dorian A.

    2014-01-01

    This study aimed to evaluate how peer-to-peer interactions through writing impact student learning in introductory-level massive open online courses (MOOCs) across disciplines. This article presents the results of a qualitative coding analysis of peer-to-peer interactions in two introductory level MOOCs: English Composition I: Achieving Expertise…

  15. Online Peer-to-Peer Communities in the Daily Lives of People With Chronic Illness

    DEFF Research Database (Denmark)

    Kingod, Natasja; Cleal, Bryan; Wahlberg, Ayo

    2017-01-01

    This qualitative systematic review investigated how individuals with chronic illness experience online peer-to-peer support and how their experiences influence daily life with illness. Selected studies were appraised by quality criteria focused upon research questions and study design, participant...... provide a supportive space for daily self-care related to chronic illness. Online communities provided a valued space to strengthen social ties and exchange knowledge that supported offline ties and patient–doctor relationships. Individuals used online communities to exchange experiential knowledge about...... selection, methods of data collection, and methods of analysis. Four themes were identified: (a) illness-associated identity work, (b) social support and connectivity, (c) experiential knowledge sharing, and (d) collective voice and mobilization. Findings indicate that online peer-to-peer communities...

  16. PKI-based security for peer-to-peer information sharing

    Energy Technology Data Exchange (ETDEWEB)

    Berket, Karlo; Essiari, Abdelilah; Muratas, Artur

    2004-05-02

    The free flow of information is the feature that has made peer-to-peer information sharing applications popular. However, this very feature holds back the acceptance of these applications by the corporate and scientific communities. In these communities it is important to provide confidentiality and integrity of communication and to enforce access control to shared resources. We present a number of security mechanisms that can be used to satisfy these security requirements. Our solutions are based on established and proven security techniques and we utilize existing technologies when possible. As a proof of concept, we have developed an information sharing system, called scishare, which integrates a number of these security mechanisms to provide a secure environment for information sharing. This system will allow a broader set of user communities to benefit from peer-to-peer information sharing.

  17. A Peer to Peer Protocol for Online Dispute Resolution over Storage Consumption

    CERN Document Server

    Mihoob, Ahmed

    2009-01-01

    In bilateral accounting of resource consumption both the consumer and provider independently measure the amount of resources consumed by the consumer. The problem here is that potential disparities between the provider's and consumer's accountings, might lead to conflicts between the two parties that need to be resolved. We argue that with the proper mechanisms available, most of these conflicts can be solved online, as opposite to in court resolution; the design of such mechanisms is still a research topic; to help cover the gap, in this paper we propose a peer--to--peer protocol for online dispute resolution over storage consumption. The protocol is peer--to--peer and takes into consideration the possible causes (e.g, transmission delays, unsynchronized metric collectors, etc.) of the disparity between the provider's and consumer's accountings to make, if possible, the two results converge.

  18. A Peer to Peer Protocol for Online Dispute Resolution over Storage Consumption

    Directory of Open Access Journals (Sweden)

    Ahmed Mihoob

    2009-06-01

    Full Text Available In bilateral accounting of resource consumption both the consumer and provider independently measure the amount of resources consumed by the consumer. The problem here is that potential disparities between the provider's and consumer's accountings, might lead to conflicts between the two parties that need to be resolved. We argue that with the proper mechanisms available, most of these conflicts can be solved online, as opposite to in court resolution; the design of such mechanisms is still a research topic; to help cover the gap, in this paper we propose a peer-to-peer protocol for online dispute resolution over storage consumption. The protocol is peer-to-peer and takes into consideration the possible causes (e.g., transmission delays, unsynchronized metric collectors, etc. of the disparity between the provider's and consumer's accountings to make, if possible, the two results converge.

  19. Analyzing Service Rates for File Transfers in Peer-to-peer File Sharing Systems

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; PAN Li; LI Jian-hua

    2008-01-01

    When examining the file transfer performance in a peer-to-peer file sharing system, a fundamental problem is how to describe the service rate for a file transfer.In this paper, the problem is examined by analyzing the distribution of server-like nodes' upstream-bandwidth among their concurrent transfers.A sufficient condition for the service rate, what a receiver obtains for downloading a file, to asymptotically be uniform is presented.On the aggregate service rate for transferring a file in a system, a sufficient condition for it to asymptotically follow a Zipf distribution is presented.These asymptotic equalities are both in the mean square sense.These analyses and the sufficient conditions provide a mathematic base for modeling file transfer processes in peer-to-peer file sharing systems.

  20. Evaluation of the CHOICES program of peer-to-peer tobacco education and advocacy.

    Science.gov (United States)

    Williams, Jill M; Dwyer, Martha; Verna, Marie; Zimmermann, Mia Hanos; Gandhi, Kunal K; Galazyn, Magdalena; Szkodny, Nancy; Molnar, Margaret; Kley, Robert; Steinberg, Marc L

    2011-06-01

    CHOICES is a consumer driven program for addressing tobacco in people with mental illness that employs mental health peer counselors. Since 2005, CHOICES has conducted over 298 community visits reaching more than 10,000 smokers with mental illness (about 2500/year). A telephone based outcome study was conducted in 102 outpatient smokers who received a CHOICES peer-to-peer session. At 1-month follow up participants (N = 86; 84%) reported smoking an average of 13 cigarettes per day which was significantly reduced from a baseline of 19 (P peer session and another 47 (55%) reduced their smoking. Feedback from smokers about the program was positive. Most (N = 59, 71%) said it was a lot easier to talk with a consumer about smoking compared to their psychiatrist or staff. Peer-to-peer communication about tobacco use can be effective to increase awareness and change smoking behaviors.

  1. Peer-to-peer Services in the Field of Accommodation: Finland vs. Latin America

    OpenAIRE

    Tuominen, Sofia; Kosunen, Sonja

    2016-01-01

    This thesis focuses on peer-to-peer services in the field of accommodation, more closely Airbnb. The thesis aims at researching the differences of the use of Airbnb in Finland and Latin America with the main focus on Mexico. The thesis is commissioned by SMAL (Association of Finnish Travel Agents). The thesis will consist of eight parts. The first part presents an overall introduction of the topic, aims, commissioner, methods and hypotheses. The second part presents the sharing economy ph...

  2. Making change easy: A peer-to-peer guide on transitioning to new hand hygiene products.

    Science.gov (United States)

    Amirov, Chingiz M; Candon, Heather L; Jacob, Latha

    2017-01-01

    This report summarizes our experiences planning and implementing the transition to a new commercial line of hand hygiene products and their dispensing systems in a large academic health care facility in Toronto, Canada. Our lessons learned are organized into a practical guide made available in 2 different formats: this article and an illustrated peer-to-peer guide (http://www.baycrest.org/wp-content/uploads/HCE-PROG-HH_HighQuality.pdf).

  3. Airbnb in tourist cities: comparing spatial patterns of hotels and peer-to-peer accommodation

    OpenAIRE

    Gutierrez, Javier; Garcia-Palomares, Juan Carlos; Romanillos, Gustavo; Salas-Olmedo, Maria Henar

    2016-01-01

    In recent years, what has become known as collaborative consumption has undergone rapid expansion through peer-to-peer (P2P) platforms. In the field of tourism, a particularly notable example is that of Airbnb. This article analyses the spatial patterns of Airbnb in Barcelona and compares them with hotels and sightseeing spots. New sources of data, such as Airbnb listings and geolocated photographs are used. Analysis of bivariate spatial autocorrelation reveals a close spatial relationship be...

  4. Securing Resources in Collaborative Environments: A Peer-to-peerApproach

    Energy Technology Data Exchange (ETDEWEB)

    Berket, Karlo; Essiari, Abdelilah; Thompson, Mary R.

    2005-09-19

    We have developed a security model that facilitates control of resources by autonomous peers who act on behalf of collaborating users. This model allows a gradual build-up of trust. It enables secure interactions among users that do not necessarily know each other and allows them to build trust over the course of their collaboration. This paper describes various aspects of our security model and describes an architecture that implements this model to provide security in pure peer-to-peer environments.

  5. Woman to woman: a peer to peer support program for women with gynecologic cancer.

    Science.gov (United States)

    Moulton, Arden; Balbierz, Amy; Eisenman, Stephanie; Neustein, Elizabeth; Walther, Virginia; Epstein, Irwin

    2013-01-01

    Gynecologic cancer has significant emotional and psychosocial implications for patients and their families. This article describes the origin and implementation of a peer to peer support program providing emotional support and information to women in treatment for gynecologic cancer and their families, in collaboration with medical and social work staff in a large, urban medical center. A formative evaluation of the program is included which suggests program participants view the program as a helpful source of support throughout treatment.

  6. ServiceStore: A Peer-to-Peer Framework for QoS-aware Service Composition

    OpenAIRE

    Jin,Jun; Zhang, Yu; Cao, Yuanda; Pu, Xing; Li, Jiaxin

    2010-01-01

    International audience; Web service composition is to integrate component services for providing a value-added new service. With the growing number of component services and their dynamic nature, the centralized composition model can't manage them efficiently and accurately. In this paper, we proposed a distributed hash table (DHT)-based peer-to-peer (P2P) service composition framework, called ServiceStore. Compared with the central control in centralized model, in our ServiceStore, service s...

  7. Peer-to-peer architectures for exascale computing : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Vorobeychik, Yevgeniy; Mayo, Jackson R.; Minnich, Ronald G.; Armstrong, Robert C.; Rudish, Donald W.

    2010-09-01

    The goal of this research was to investigate the potential for employing dynamic, decentralized software architectures to achieve reliability in future high-performance computing platforms. These architectures, inspired by peer-to-peer networks such as botnets that already scale to millions of unreliable nodes, hold promise for enabling scientific applications to run usefully on next-generation exascale platforms ({approx} 10{sup 18} operations per second). Traditional parallel programming techniques suffer rapid deterioration of performance scaling with growing platform size, as the work of coping with increasingly frequent failures dominates over useful computation. Our studies suggest that new architectures, in which failures are treated as ubiquitous and their effects are considered as simply another controllable source of error in a scientific computation, can remove such obstacles to exascale computing for certain applications. We have developed a simulation framework, as well as a preliminary implementation in a large-scale emulation environment, for exploration of these 'fault-oblivious computing' approaches. High-performance computing (HPC) faces a fundamental problem of increasing total component failure rates due to increasing system sizes, which threaten to degrade system reliability to an unusable level by the time the exascale range is reached ({approx} 10{sup 18} operations per second, requiring of order millions of processors). As computer scientists seek a way to scale system software for next-generation exascale machines, it is worth considering peer-to-peer (P2P) architectures that are already capable of supporting 10{sup 6}-10{sup 7} unreliable nodes. Exascale platforms will require a different way of looking at systems and software because the machine will likely not be available in its entirety for a meaningful execution time. Realistic estimates of failure rates range from a few times per day to more than once per hour for these

  8. Peer-to-peer architectures for exascale computing : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Vorobeychik, Yevgeniy; Mayo, Jackson R.; Minnich, Ronald G.; Armstrong, Robert C.; Rudish, Donald W.

    2010-09-01

    The goal of this research was to investigate the potential for employing dynamic, decentralized software architectures to achieve reliability in future high-performance computing platforms. These architectures, inspired by peer-to-peer networks such as botnets that already scale to millions of unreliable nodes, hold promise for enabling scientific applications to run usefully on next-generation exascale platforms ({approx} 10{sup 18} operations per second). Traditional parallel programming techniques suffer rapid deterioration of performance scaling with growing platform size, as the work of coping with increasingly frequent failures dominates over useful computation. Our studies suggest that new architectures, in which failures are treated as ubiquitous and their effects are considered as simply another controllable source of error in a scientific computation, can remove such obstacles to exascale computing for certain applications. We have developed a simulation framework, as well as a preliminary implementation in a large-scale emulation environment, for exploration of these 'fault-oblivious computing' approaches. High-performance computing (HPC) faces a fundamental problem of increasing total component failure rates due to increasing system sizes, which threaten to degrade system reliability to an unusable level by the time the exascale range is reached ({approx} 10{sup 18} operations per second, requiring of order millions of processors). As computer scientists seek a way to scale system software for next-generation exascale machines, it is worth considering peer-to-peer (P2P) architectures that are already capable of supporting 10{sup 6}-10{sup 7} unreliable nodes. Exascale platforms will require a different way of looking at systems and software because the machine will likely not be available in its entirety for a meaningful execution time. Realistic estimates of failure rates range from a few times per day to more than once per hour for these

  9. Peer-to-Peer and Mass Communication Effect on Revolution Dynamics

    CERN Document Server

    Kindler, Alex; Stauffer, Dietrich

    2012-01-01

    Revolution dynamics is studied through a minimal Ising model with three main influences (fields): personal conservatism (power-law distributed), inter-personal and group pressure, and a global field incorporating peer-to-peer and mass communications, which is generated bottom-up from the revolutionary faction. A rich phase diagram appears separating possible terminal stages of the revolution, characterizing failure phases by the features of the individuals who had joined the revolution. An exhaustive solution of the model is produced, allowing predictions to be made on the revolution's outcome.

  10. Distributed High Accuracy Peer-to-Peer Localization in Mobile Multipath Environments

    CERN Document Server

    Ekambaram, Venkatesan

    2010-01-01

    In this paper we consider the problem of high accuracy localization of mobile nodes in a multipath-rich environment where sub-meter accuracies are required. We employ a peer to peer framework where the vehicles/nodes can get pairwise multipath-degraded ranging estimates in local neighborhoods together with a fixed number of anchor nodes. The challenge is to overcome the multipath-barrier with redundancy in order to provide the desired accuracies especially under severe multipath conditions when the fraction of received signals corrupted by multipath is dominating. We invoke a message passing analytical framework based on particle filtering and reveal its high accuracy localization promise through simulations.

  11. Jornada “Usos i abusos del peer-to-peer

    Directory of Open Access Journals (Sweden)

    Raquel Xalabarder

    2010-07-01

    Full Text Available El 3 de desembre de 2009, els Estudis de Dret i Ciència Política de la Universitat Oberta de Catalunya (UOC, juntament amb l'Internet Interdisciplinary Institute (IN3, van organitzar la jornada "Usos i abusos del peer-to-peer", que va tenir lloc a la seu central de la UOC a Barcelona. La jornada la van coordinar els professors d'aquests Estudis integrants del grup de recerca Interdret de l'IN3.

  12. Accurate Detection of Peer-to-Peer Botnet using Multi-Stream Fused Scheme

    Directory of Open Access Journals (Sweden)

    Jian Kang

    2011-05-01

    Full Text Available Nowadays decentralized botnets pose a great threat to Internet. They evolve new features such as P2P Command and Control(C&C, which makes traditional detection methods no longer effective for indicating the existence of the bots. In this paper, based on several of the new P2P botnet characteristic properties, we propose a novel real-time detecting model – MSFM (Multi-Stream Fused Model. MSFM considers multiple types of packets’ unique characteristics and handle them with corresponding strategies. Extensive experiment results show that our model can accurately detect peer-to-peer botnet with relatively low false-positive and false-negative rates.

  13. Peer-to-peer and mass communication effect on opinion shifts

    Science.gov (United States)

    Kindler, A.; Solomon, S.; Stauffer, D.

    2013-02-01

    Opinion dynamics is studied through a minimal Ising model with three main influences (fields): personal conservatism (power-law distributed), inter-personal and group pressure, and a global field incorporating peer-to-peer and mass communications, which is generated bottom-up from the faction supporting the new opinion. A rich phase diagram appears separating possible terminal stages of the opinion diffusion, characterizing failure phases by the features of the individuals who had changed their opinion. An exhaustive solution of the model is produced, allowing predictions to be made on the opinion’s assimilation in the society.

  14. ISP-Unterstützte Auswahl von Peer Knoten in Peer-to-Peer Systemen

    OpenAIRE

    Aggarwal, Vinay

    2009-01-01

    Peer-to-Peer (P2P) Systeme verursachen heutzutage mehr als die Hälfte des Internetverkehrs, und eine wachsende Anzahl von Applikationen, z.B. Bittorrent, eDonkey, Joost, Skype, GoogleTalk und P2P-TV nutzen die P2P-Methodik. P2P-Systeme errichten Overlays auf der Applikationsschicht, unabhängig von Internet-Routing und ISP-Topologien. Dies führt zu zusätzlichen Verkehr aufgrund der Messungen sowie ineffizientes Routing für P2P-Benutzer. Während auf der einen Seite die P2P-Applikationen den Bro...

  15. A hierarchical framework for peer-to peer systems: design and optimizations

    OpenAIRE

    Sánchez Artigas, Marc

    2009-01-01

    En los últimos años, las redes peer-to-peer (P2P) ha experimentado una fuerte expansión. Estos sustratos se constituyen en forma de redes overlay o de recubrimiento que interconectan usuarios de manera lógica y desacoplada de la topología física, y que proporcionan un servicio descentralizado de búsqueda de recursos. Existen dos grandes familias de redes P2P descentralizadas: las redes P2P desestructuradas y las redes P2P estructuradas. Desde el punto de vista funcional, las redes estructurad...

  16. Author's rights in the digital age: how Internet and peer-to-peer file sharing technology shape the perception of copyrights and copywrongs

    Directory of Open Access Journals (Sweden)

    Milijana Micunovic

    2016-01-01

    Full Text Available Author's rights and copyright law have gone through quite a few changes in the 'post-print' culture of binary systems, digital formations and techno-practices. Technological development supports new concept of author's rights by promoting free internet and digital market, as well as new contemporary experience of culture that is being rooted in digital technology, mass communication and the world of multimedia and virtuality. Though computer and digital technology have served both authors and users in various ways, they have also served as a very fertile ground for sharing copyrighted content thus leading to numerous copyright infringements and conflicts with the copyright law. The aim of this paper is to identify and analyze the ways in which computer and digital technology have given rise to new trends in the production (e.g. remix culture and consumption (e.g. peer-to-peer file sharing technology of culture, but also to determine how new forms of distribution, use and sharing of digital content changed and shaped the perception of authorship in the 21st century. In order to analyze the dynamic, nature and structure by which new digital and networking technologies are affecting the concept of authorship and author's rights and to test the consistency of previously established hypotheses, we conducted a survey amongst general public. Altogether 535 questionnaires were completed. Data was analyzed using SPSS tool and quantitative method of analysis. In the analysis special attention was given to both, the concept of authorship in the digital environment and the concept of peer-to-peer file sharing technology as not so new, but still very popular networked architecture for distributing, using and sharing digital content. Results have shown that most of the respondents use peer-to-peer file sharing technology to access, consume and/or share different cultural content (e.g. movies, music, books, etc. while violating the rights of copyright holders

  17. PowerFolder – Peer-to-Peer powered Sync and Share

    CERN Document Server

    CERN. Geneva

    2014-01-01

    PowerFolder is a peer-to-peer (P2P) sync and share solution which started as spin-off from the University of Cologne and University of Applied Science Niederrhein in 2007. It is available as commercial and open-source solution and in use by hundreds of education and research organization and several thousand businesses. The software enables datacenter providers, NRENs or any education and research organization to operate its own PowerFolder cloud as alternative to public clouds while preserving the same end-user experience: Access to data anywhere on any device (Windows, Linux, Apple, Web, Android and iOS). While approaches to sync and share data from/to a single central location have several drawbacks the PowerFolder solution offers a unique peer-to-peer algorithm to replicate and transfer data between sites, users and devices with the freedom to choose whether to store or not to store files at the central hub. This is archived by intelligent; decentralize meta- and binary-data handling between nodes in a se...

  18. A NOVEL APPROACH TO TRANSFORM CLASSICAL DATABASE TO USER FRIENDLY WEB DOCUMENT FOR MEDICAL APPLICATION IN PEER-TO-PEER ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    E. Anupriya,

    2010-11-01

    Full Text Available Due to the increasing popularity of the XML (eXtensible Markup Language as a common data standard for information interchange across Web, XML is commonly being used as an underlying data model for many applications to deal with the heterogeneity of data and nodes. This paper presents a novel approach to extract data from classical database systems like relational database systems, convert it into XML documents, and exchange XML documents among peer nodes in the network. Many hospitals have branches in different geographicallocations. The chief doctors need to travel to different locations and give consultation. If the peer hospital nodes are connected in peer-to-peer network, then the consultation can be provided from any peer hospital node even under emergencies. Peer-to-Peer network is implemented via Byzantine-Resilient Secure Multicast Routing in ultihop Wireless Networks (BSMR protocol enhanced with security. Also, we have considered and emulated a system for one such medical application in which the consultant can enter details like insulin dosage to be given or any pre or post sugar measurements need to be taken for any in patients available in the peer hospitals. The concerned duty doctor and nurses can carryout the task based on instruction in any peer hospital node. To make it easily readable,the information is presented in browser as a XML document.

  19. Organic Collaborative Teams: The Role of Collaboration and Peer to Peer Support for Part-Time Doctoral Completion

    Directory of Open Access Journals (Sweden)

    Cathy M. Littlefield

    2015-02-01

    Full Text Available With doctoral completion rates hovering around 50%, students, faculty and institutions are seeking methods for improvement. This narrative inquiry examined the impact of collaboration and peer to peer experiences on doctoral completion of three peers in a part-time doctoral program. Prior to this inquiry, minimal research existed on the impact of peer to peer support and collaboration on doctoral completion; therefore, the three peer authors defined, described, and recommended ways to encourage organic collaboration. The authors’ defined organic collaboration as a naturally-formed dynamic peer to peer support group, built on individual strengths and differences, while focused on a common goal. Themes found during the narrative inquiry included the identification of a common goal, amicable group dynamics, peer to peer support, and intentional relational learning. The peer authors provided practical knowledge on ways students, faculty and higher education institutions can benefit from encouraging and supporting organic collaboration. This narrative inquiry demonstrated the long-term benefits of peer to peer support and collaboration that led to scholarly, professional, and personal support.

  20. A Preliminary Study of Peer-to-Peer Human-Robot Interaction

    Science.gov (United States)

    Fong, Terrence; Flueckiger, Lorenzo; Kunz, Clayton; Lees, David; Schreiner, John; Siegel, Michael; Hiatt, Laura M.; Nourbakhsh, Illah; Simmons, Reid; Ambrose, Robert

    2006-01-01

    The Peer-to-Peer Human-Robot Interaction (P2P-HRI) project is developing techniques to improve task coordination and collaboration between human and robot partners. Our work is motivated by the need to develop effective human-robot teams for space mission operations. A central element of our approach is creating dialogue and interaction tools that enable humans and robots to flexibly support one another. In order to understand how this approach can influence task performance, we recently conducted a series of tests simulating a lunar construction task with a human-robot team. In this paper, we describe the tests performed, discuss our initial results, and analyze the effect of intervention on task performance.

  1. MAPPS: A Framework of Peer-to-Peer Systems Based on JXTA and Mobile Agents

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Due to the success of Napster, Gnutella and Freenet, peer to peer (P2P) computing has suddenly emerged at the forefront of Internet computing. And a lot of problems including security, reliability and rooting are urgent to be solved.Unfortunately, traditional techniques are not directly applicable to P2P systems. This paper presents a new framework called MAPPS for designing P2P applications based on JXTA and mobile agents. The MAPPS framework is structured as three layers:the MAPPS infiastmcture based on mobile agents, MAPPS services and MAPPS applications. In this way, MAPPS not only follows the ootstanding architecture of JXTA, but also enhances the mobility and flexibility of P2P systems. Using MAPPS,developers of new P2P systems can design and implement P2P systems more efficiently.

  2. Inferring Metadata for a Semantic Web Peer-to-Peer Environment

    Directory of Open Access Journals (Sweden)

    Mark Painter

    2004-04-01

    Full Text Available Learning Objects Metadata (LOM aims at describing educational resources in order to allow better reusability and retrieval. In this article we show how additional inference rules allows us to derive additional metadata from existing ones. Additionally, using these rules as integrity constraints helps us to define the constraints on LOM elements, thus taking an important step toward a complete axiomatization of LOM metadata (with the goal of transforming the LOM definitions from a simple syntactical description into a complete ontology. We will use RDF metadata descriptions and Prolog as an inference language. We show how these rules can be applied for the extensions of course metadata using an existing test bed with several courses. Based on the Edutella peer-to-peer architecture we can easily make RDF metadata accessible to a whole community using Edutella peers that manage RDF metadata. By processing inference rules we can achieve better search results.

  3. Secure Channel Free ID-Based Searchable Encryption for Peer-to-Peer Group

    Institute of Scientific and Technical Information of China (English)

    Xiao-Fen Wang; Yi Mu; Rongmao Chen; Xiao-Song Zhang

    2016-01-01

    Data sharing and searching are important functionalities in cloud storage. In this paper, we show how to securely and flexibly search and share cloud data among a group of users without a group manager. We formalize a novel cryptosystem: secure channel free searchable encryption in a peer-to-peer group, which features with the secure cloud data sharing and searching for group members in an identity-based setting. Our scheme allows group members to join or leave the group dynamically. We present two schemes: basic scheme and enhanced scheme. We formally prove that our basic scheme achieves consistency and indistinguishability against the chosen keyword and ciphertext attack and the outsider’s keyword guessing attack, respectively. An enhanced scheme is also proposed to achieve forward secrecy, which allows to revoke user search right over the former shared data.

  4. A Peer-to-Peer Middleware Framework for Resilient Persistent Programming

    CERN Document Server

    Dearle, Alan; Norcross, Stuart; McCarthy, Andrew

    2010-01-01

    The persistent programming systems of the 1980s offered a programming model that integrated computation and long-term storage. In these systems, reliable applications could be engineered without requiring the programmer to write translation code to manage the transfer of data to and from non-volatile storage. More importantly, it simplified the programmer's conceptual model of an application, and avoided the many coherency problems that result from multiple cached copies of the same information. Although technically innovative, persistent languages were not widely adopted, perhaps due in part to their closed-world model. Each persistent store was located on a single host, and there were no flexible mechanisms for communication or transfer of data between separate stores. Here we re-open the work on persistence and combine it with modern peer-to-peer techniques in order to provide support for orthogonal persistence in resilient and potentially long-running distributed applications. Our vision is of an infrastr...

  5. Writing to Learn and Learning to Write across the Disciplines: Peer-to-Peer Writing in Introductory-Level MOOCs

    Directory of Open Access Journals (Sweden)

    Denise K. Comer

    2014-11-01

    Full Text Available This study aimed to evaluate how peer-to-peer interactions through writing impact student learning in introductory-level massive open online courses (MOOCs across disciplines. This article presents the results of a qualitative coding analysis of peer-to-peer interactions in two introductory level MOOCs: English Composition I: Achieving Expertise and Introduction to Chemistry. Results indicate that peer-to-peer interactions in writing through the forums and through peer assessment enhance learner understanding, link to course learning objectives, and generally contribute positively to the learning environment. Moreover, because forum interactions and peer review occur in written form, our research contributes to open distance learning (ODL scholarship by highlighting the importance of writing to learn as a significant pedagogical practice that should be encouraged more in MOOCs across disciplines.

  6. Peer-to-peer psychological contracts in the South African wine industry

    Directory of Open Access Journals (Sweden)

    Ruth Penfold

    2015-03-01

    Full Text Available Orientation: Very few studies examine the impact of peer relationships on the psychological contract.Research purpose: Using the backdrop of wine farm workers in the Western Cape, South Africa, the aim of our study was to explore the nature of peer relationships shaping the psychological contract. Motivation for the study: The agricultural sector of South Africa, in particular the wine farms in the Western Cape, has undergone radical change in the past decades as a result of labour legislation and changing government structures. It was therefore expected that these changes would influence the psychological contracts held by wine farm workers.Research approach, design and method: This qualitative study sampled all 24 full-time employees and 2 managers on the Constantia Hills Wine Estate in Cape Town, South Africa. Semi-structured interviews were conducted using the critical incident technique in combination with a series of open questions.Main findings: Our findings showed support for the existence of peer-to-peer psychological contracts and noted the valuable influence of a suitable conduit individual on the relationship between employees and their employer.Practical and/or managerial implications: Wine farm workers in South Africa have a strong need to be consulted after a lifetime of having no voice. In addition to ensuring suitable levels of two-way communication, management must understand the inter-peer contract and the nature of the relationships sustaining it.Contribution: Whilst literature has suggested that management of the psychological contract lies firmly within the domain of the employer, our findings indicated that ensuring harmonious peer-to-peer contracts was also central to good working relationships.

  7. Economic models for management of resources in peer-to-peer and grid computing

    Science.gov (United States)

    Buyya, Rajkumar; Stockinger, Heinz; Giddy, Jonathan; Abramson, David

    2001-07-01

    The accelerated development in Peer-to-Peer (P2P) and Grid computing has positioned them as promising next generation computing platforms. They enable the creation of Virtual Enterprises (VE) for sharing resources distributed across the world. However, resource management, application development and usage models in these environments is a complex undertaking. This is due to the geographic distribution of resources that are owned by different organizations or peers. The resource owners of each of these resources have different usage or access policies and cost models, and varying loads and availability. In order to address complex resource management issues, we have proposed a computational economy framework for resource allocation and for regulating supply and demand in Grid computing environments. The framework provides mechanisms for optimizing resource provider and consumer objective functions through trading and brokering services. In a real world market, there exist various economic models for setting the price for goods based on supply-and-demand and their value to the user. They include commodity market, posted price, tenders and auctions. In this paper, we discuss the use of these models for interaction between Grid components in deciding resource value and the necessary infrastructure to realize them. In addition to normal services offered by Grid computing systems, we need an infrastructure to support interaction protocols, allocation mechanisms, currency, secure banking, and enforcement services. Furthermore, we demonstrate the usage of some of these economic models in resource brokering through Nimrod/G deadline and cost-based scheduling for two different optimization strategies on the World Wide Grid (WWG) testbed that contains peer-to-peer resources located on five continents: Asia, Australia, Europe, North America, and South America.

  8. D4V: a peer-to-peer architecture for data dissemination in smartphone-based vehicular applications

    Directory of Open Access Journals (Sweden)

    Marco Picone

    2015-08-01

    Full Text Available Vehicular data collection applications are emerging as an appealing technology to monitor urban areas, where a high concentration of connected vehicles with onboard sensors is a near future scenario. In this context, smartphones are, on one side, effective enablers of Vehicle-to-Vehicle (V2V and Vehicle-to-Infrastructure (V2I applications and, on the other side, highly sophisticated sensing platforms. In this paper, we introduce an effective and efficient system, denoted as D4V, to disseminate vehicle-related information and sensed data using smartphones as V2I devices. D4V relies on a Peer-to-Peer (P2P overlay scheme, denoted as Distributed Geographic Table (DGT, which unifies the concepts of physical and virtual neighborhoods in a scalable and robust infrastructure for application-level services. First, we investigate the discovery procedure of the DGT overlay network, through analytical and simulation results. Then, we present and discuss an extensive simulation-based performance evaluation (considering relevant performance indicators of the D4V system, in a 4G wireless communication scenario. The simulation methodology combines DEUS (an application-level simulation tool for the study of large-scale systems with ns-3 (a well-known network simulator, which takes into account lower layers, in order to provide a D4V proof-of-concept. The observed results show that D4V-based information sharing among vehicles allows to significantly reduce risks and nuisances (e.g., due to road defects and congestions.

  9. ON MULTICAST TREE CONSTRUCTION IN IPV4-IPV6 HYBRID NETWORK

    Institute of Scientific and Technical Information of China (English)

    Zhang Chao; Zhang Yuan; Huang Yongfeng; Li Xing

    2010-01-01

    With the IPv4 addresses exhausting and IPv6 emerging,the Peer-to-Peer (P2P) overlay is becoming increasingly heterogeneous and complex: pure IPv4,dual stack and pure IPv6 hosts coexist,and the connectivity limitation between IPv4 and IPv6 hosts requires the overlay protocols to be fit for this hybrid situation. This paper sets out to answer the question of how to construct multicast tree on top of IPv4-IPv6 hybrid network. Our solution is a New Greedy Algorithm (NGA) which eliminates the problem of joining failure in the hybrid network and keeps the efficiency of greedy algorithm in tree construction. Simulation results show that our algorithm has excellent performance,which is very close to the optimal in many cases.

  10. Screening in new credit markets: can individual lenders infer borrower creditworthiness in peer-to-peer lending?

    NARCIS (Netherlands)

    Iyer, R.; Khwaja, A.I.; Luttmer, E.F.P.; Shue, K.

    2009-01-01

    The current banking crisis highlights the challenges faced in the traditional lending model, particularly in terms of screening smaller borrowers. The recent growth in online peer-to-peer lending marketplaces offers opportunities to examine different lending models that rely on screening by multiple

  11. Comparison of the mean-field approach and simulation in a peer-to-peer botnet case study

    NARCIS (Netherlands)

    Kolesnichenko, A.V.; Remke, Anne Katharina Ingrid; de Boer, Pieter-Tjerk; Haverkort, Boudewijn R.H.M.; Thomas, N.

    2011-01-01

    Peer-to-peer botnets, as exemplified by the Storm Worm and Stuxnet, are a relatively new threat to security on the internet: infected computers automatically search for other computers to be infected, thus spreading the infection rapidly. In a recent paper, such botnets have been modeled using Stoch

  12. IK BEN STER(K) : Empowering young adults through a peer-to-peer talent development platform

    NARCIS (Netherlands)

    Mulder, I.J.; Pucci, E.L.

    2014-01-01

    IK BEN STER(K). Empowering young adults through a peer-to-peer talent development platform. Paper presented at FabLabs in Educational Context: A Retrospective and Outlook. Workshop held in conjunction with FabLearn Europe 2014, June 16, 2014, Aarhus, Denmark.

  13. Partnerships Enhancing Practice: A Preliminary Model of Technology-Based Peer-to-Peer Evaluations of Teaching in Higher Education

    Science.gov (United States)

    Servilio, Kathryn L.; Hollingshead, Aleksandra; Hott, Brittany L.

    2017-01-01

    In higher education, current teaching evaluation models typically involve senior faculty evaluating junior faculty. However, there is evidence that peer-to-peer junior faculty observations and feedback may be just as effective. This descriptive case study utilized an inductive analysis to examine experiences of six special education early career…

  14. a mathematical framework for analyzing incentives in peer-to-peer ...

    African Journals Online (AJOL)

    characteristics; self-organization, distributed control and symmetric communication ..... et al, 2003) This is due to the fact that P2P networks are more of a concept (Roussopoulos et al,. 2004). Currently, all P2P can be classified based on structure as ... which is the most common is further divided into centralized, hybrid and.

  15. Future Structure of the Life-World. As an inevitable consequence of the «peer-to-peer»

    Directory of Open Access Journals (Sweden)

    Mototaka Mori

    2016-01-01

    Full Text Available This article intends to draw theoretically a future structure of the life-world. The state interventionism in the late capitalism has been often argued by the critical theoreticians like Jurgen Habermas since the last half of the twentieth century. It was particularly the main problem how possible the life-world was in such the technologically systematized society. However, the highly technological development of telecommunication has changed our everyday life very rapidly and totally. If we know such the rapid change of coevolution between human life and technology, we have to fundamentally reconsider on the theory of life-world. Therefore, in this article I will firstly focus on the classical theory of mundane social world which Alfred Schutz presented in the early 1930s. Of course, his project of socio-phenomenology has been one of the most brilliant und important works still now. However, his theory also will have to be renewed. If we know particularly the «peer-to-peer» constellation of the computer network by the distributed anonymous persons, the classical model of life-world must be versioned up to a next theoretical level. Secondly, considering on the virtual currency like the Bitcoin, this article will show you a hypothetical aspect of transformation of the life-world. The mechanism of trust, which has been often understood as one of the most important key concepts for the community or the society, may be replaced with the computer technology of cryptographic proof. Such a theoretical examination will finally lead to an important opened problem. We will have to inquire whether such the social order will be spontaneous, or whether such the ordering will have to be decided only by the speed of computer’s central processing unit.

  16. Efficient User Authentication and Key Management for Peer-to-Peer Live Streaming Systems

    Institute of Scientific and Technical Information of China (English)

    LIU Xuening; YIN Hao; LIN Chuang; DU Changlai

    2009-01-01

    Recent development of the peer-to-peer (P2P) live streaming technique has brought unprece-dented new momentum to the Internet with the characters of effective, scalable, and low cost. However, be-fore these applications can be successfully deployed as commercial applications, efficient access control mechanisms are needed. This work based on earlier research of the secure streaming architecture in Trust-Stream, analyzes how to ensure that only authorized users can access the original media in the P2P live streaming system by adopting a user authentication and key management scheme. The major features of this system include (1) the management server issues each authorized user a unique public key certificate,(2) the one-way hash chain extends the certificate's lifetime, (3) the original media is encrypted by the ses-sion key and delivered to the communication group, and (4) the session key is periodically updated and dis-tributed with the media. Finally, analyses and test results show that scheme provides a secure, scalable, re-liable, and efficient access control solution for P2P live streaming systems.

  17. Queued History based Mediator Identification for an Incentive Attached peer to peer Electronic Coupon System

    Science.gov (United States)

    Shojima, Taiki; Ikkai, Yoshitomo; Komoda, Norihisa

    An incentive attached peer to peer (P2P) electronic coupon system is proposed in which users forward e-coupons to potential users by providing incentives to those mediators. A service provider needs to acquire distribution history for incentive payment by recording UserIDs (UIDs) in the e-coupons, since this system is intended for pure P2P environment. This causes problems of dishonestly altering distribution history. In order to solve such problems, distribution history is realized in a couple of queues structure. They are the UID queue, and the public key queue. Each element of the UID queue at the initial state consists of index, a secret key, and a digital signature. In recording one's UID, the encrypted UID is enqueued to the UID queue with a new digital signature created by a secret key of the dequeued element, so that each UID cannot be altered. The public key queue provides the functionality of validating digital signatures on mobile devices. This method makes it possible both each UID and sequence of them to be certificated. The availability of the method is evaluated by quantifying risk reduction using Fault Tree Analysis (FTA). And it's recognized that the method is better than common encryption methods.

  18. Munin: A Peer-to-Peer Middleware for Ubiquitous Analytics and Visualization Spaces.

    Science.gov (United States)

    Badam, Sriram Karthik; Fisher, Eli; Elmqvist, Niklas

    2015-02-01

    We present Munin, a software framework for building ubiquitous analytics environments consisting of multiple input and output surfaces, such as tabletop displays, wall-mounted displays, and mobile devices. Munin utilizes a service-based model where each device provides one or more dynamically loaded services for input, display, or computation. Using a peer-to-peer model for communication, it leverages IP multicast to replicate the shared state among the peers. Input is handled through a shared event channel that lets input and output devices be fully decoupled. It also provides a data-driven scene graph to delegate rendering to peers, thus creating a robust, fault-tolerant, decentralized system. In this paper, we describe Munin's general design and architecture, provide several examples of how we are using the framework for ubiquitous analytics and visualization, and present a case study on building a Munin assembly for multidimensional visualization. We also present performance results and anecdotal user feedback for the framework that suggests that combining a service-oriented, data-driven model with middleware support for data sharing and event handling eases the design and execution of high performance distributed visualizations.

  19. Extended Equal Service and Differentiated Service Models for Peer-to-Peer File Sharing

    CERN Document Server

    Zhang, Jianwei; Xing, Wei; Lu, Dongming

    2012-01-01

    Peer-to-Peer (P2P) systems have proved to be the most effective and popular file sharing applications in recent years. Previous studies mainly focus on the equal service and the differentiated service strategies when peers have no initial data before their download. In an upload-constrained P2P file sharing system, we model both the equal service process and the differentiated service process when peers' initial data distribution satisfies some special conditions, and also show how to minimize the time to get the file to any number of peers. The proposed models can reveal the intrinsic relations among the initial data amount, the size of peer set and the minimum last finish time. By using the models, we can also provide arbitrary degree of differentiated service to a certain number of peers. We believe that our analysis process and achieved theoretical results could provide fundamental insights into studies on bandwidth allocation and data scheduling, and can give helpful reference both for improving system p...

  20. Improvement of Incentive Mechanism on BitTorrent-like Peer-to-Peer File Sharing Systems

    Institute of Scientific and Technical Information of China (English)

    YU Jia-di; LI Ming-lu; HONG Feng; XUE Guang-tao

    2007-01-01

    BitTorrent is a very popular Peer.to-Peer file sharing system, which adopts a set of incentive mechanisms to encourage contribution and prevent free-riding. However,we find that BitTorrent's incentive mechanism can prevent free-riding effectively in a system with a relatively low number of seeds, but may fail in producing a disincentive for free-riding in a system with a high number of seeds. The reason is that BitTorrent does not provide effective mechanisms for seeds to guard against free-riding.Therefore, we propose a seed bandwidth allocation strategy for the BitTorrent system to reduce the effect of seeds on free-riding. Our target is that a downloader which provides more service to the system will be granted a higher benefit than downloaders which provide lower service when some downioaders ask for downloading file from a seed. Finally,simulation results are given, which validate the effectiveness of the proposed strategy.

  1. Green: Towards a Pollution-Free Peer-to-Peer Content Sharing Service

    CERN Document Server

    Chen, Ruichuan; Cai, Zhuhua; Crowcroft, Jon; Chen, Zhong

    2011-01-01

    Peer-to-Peer (P2P) content sharing systems are susceptible to the content pollution attack, in which attackers aggressively inject polluted contents into the systems to reduce the availability of authentic contents, thus decreasing the confidence of participating users. In this paper, we design a pollution-free P2P content sharing system, Green, by exploiting the inherent content-based information and the social-based reputation. In Green, a content provider (i.e., creator or sharer) publishes the information of his shared contents to a group of content maintainers self-organized in a security overlay for providing the mechanisms of redundancy and reliability, so that a content requestor can obtain and filter the information of his requested content from the associated maintainers. We employ a reputation model to help the requestor better identify the polluted contents, and then utilize the social (friend-related) information to enhance the effectiveness and efficiency of our reputation model. Now, the reques...

  2. Peer to Peer Optimistic Collaborative Editing on XML-like trees

    CERN Document Server

    Lugiez, Denis

    2009-01-01

    Collaborative editing consists in editing a common document shared by several independent sites. This may give rise to conficts when two different users perform simultaneous uncompatible operations. Centralized systems solve this problem by using locks that prevent some modifications to occur and leave the resolution of confict to users. On the contrary, peer to peer (P2P) editing doesn't allow locks and the optimistic approach uses a Integration Transformation IT that reconciliates the conficting operations and ensures convergence (all copies are identical on each site). Two properties TP1 and TP2, relating the set of allowed operations Op and the transformation IT, have been shown to ensure the correctness of the process. The choice of the set Op is crucial to define an integration operation that satisfies TP1 and TP2. Many existing algorithms don't satisfy these properties and are indeed incorrect i.e. convergence is not guaranteed. No algorithm enjoying both properties is known for strings and little work...

  3. An Adaptive Checkpointing Scheme for Peer-to-Peer Based Volunteer Computing Work Flows

    CERN Document Server

    Ni, Lei

    2007-01-01

    Volunteer Computing, sometimes called Public Resource Computing, is an emerging computational model that is very suitable for work-pooled parallel processing. As more complex grid applications make use of work flows in their design and deployment it is reasonable to consider the impact of work flow deployment over a Volunteer Computing infrastructure. In this case, the inter work flow I/O can lead to a significant increase in I/O demands at the work pool server. A possible solution is the use of a Peer-to- Peer based parallel computing architecture to off-load this I/O demand to the workers; where the workers can fulfill some aspects of work flow coordination and I/O checking, etc. However, achieving robustness in such a large scale system is a challenging hurdle towards the decentralized execution of work flows and general parallel processes. To increase robustness, we propose and show the merits of using an adaptive checkpoint scheme that efficiently checkpoints the status of the parallel processes accordin...

  4. H-Trust:A Group Trust Management System for Peer-to-Peer Desktop Grid

    Institute of Scientific and Technical Information of China (English)

    Huanyu Zhao; Xiaolin Li

    2009-01-01

    Peer-to-Peer Desktop Grid(P2PDG)has emerged as a pervasive cyber-infrastructure tackling many largescale applications with high impacts.As a burgeoning research area,P2PDG can support numerous applications,including scientific computing,file sharing,web services,and virtual organization for collaborative activities and projects.To handle trustworthiness issues of these services.trust and reputation schemes are proposed to establish trust among peers in P2PDG.In this paper,we propose a robust group trust management system,called H-Trust,inspired by the H-index aggregation technique.Leveraging the robustness of the H-index algorithm under incomplete and uncertain circumstances.H-Trust offers a robust personalized reputation evaluation mechanism for both individual and group trusts with minimal communication and computation overheads.We present the H-Trust scheme in five phases,including trust recording,local trust evaluation,trust query phase,spatiai-temporal update phase,and group reputation evaluation phases.The rationale for its design,the analysis of the algorithm are further investigated.To validate the performance of H-Trust scheme.we designed the H-Trust simulator HTrust-Sim to conduct multi-agent-based simulations.Simulation results demonstrate that H-Trust is robust and can identify and isolate malicious peers in large scale systems even when a large portion of peers are malicious.

  5. AntBot: Anti-pollution peer-to-peer botnets

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-01

    Botnets, which are responsible for many email sparnming and DDoS (Distributed Denial of Service) attacks in the current Internet, have emerged as one of most severe cyber-threats in recent years. To evade detection and improve resistance against countermeasures, botnets have evolved from the first generation that relies on IRC chat channels to deliver commands to the current generation that uses highly resilient P2P (Peer-to-Peer) protocols to spread their C&C (Command and Control) information. It is, however, revealed that P2P botnets, although relieved from the single point of failure that IRC botnets suffer, can be easily disrupted using pollution-based mitigation schemes [15]. In this paper, we play the devil's advocate and propose a new type of hypothetical botnets called AntBot, which aim to propagate their C&C information to individual bots even though there exists an adversary that persistently pollutes keys used by seized bots to search the command information. The key idea of AntBot is a tree-like structure that bots use to deliver the command so that captured bots reveal only limited information. To evaluate effectiveness of AntBot against pollution-based mitigation in a virtual environment, we develop a distributed P2P botnet simulator. Using extensive experiments, we demonstrate that AntBot operates resiliently against pollution-based mitigation. We further present a few potential defense schemes that could effectively disrupt AntBot operations.

  6. RatBot: anti-enumeration peer-to-peer botnets

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Guanhua [Los Alamos National Laboratory; Eidenbenz, Stephan [Los Alamos National Laboratory; Chen, Songqing [GEORGE MASON UNIV.

    2010-01-01

    Botnets have emerged as one of the most severe cyber threats in recent years. To obtain high resilience against a single point of failure, the new generation of botnets have adopted the peer-to-peer (P2P) structure. One critical question regarding these P2P botnets is: how big are they indeed? To address this question, researchers have proposed both actively crawling and passively monitoring methods to enumerate existing P2P botnets. In this work, we go further to explore the potential strategies that botnets may have to obfuscate their true sizes. Towards this end, this paper introduces RatBot, a P2P botnet that applies some statistical techniques to defeat existing P2P botnet enumeration methods. The key ideas of RatBot are two-fold: (1) there exist a fraction of bots that are indistinguishable from their fake identities, which are spoofing IP addresses they use to hide themselves; (2) we use a heavy-tailed distribution to generate the number of fake identities for each of these bots so that the sum of observed fake identities converges only slowly and thus has high variation. We use large-scale high-fidelity simulation to quantify the estimation errors under diverse settings, and the results show that a naive enumeration technique can overestimate the sizes of P2P botnets by one order of magnitude. We believe that our work reveals new challenges of accurately estimating the sizes of P2P botnets, and hope that it will raise the awareness of security practitioners with these challenges. We further suggest a few countermeasures that can potentially defeat RatBot's anti-enumeration scheme.

  7. Online Peer-to-Peer Communities in the Daily Lives of People With Chronic Illness: A Qualitative Systematic Review

    DEFF Research Database (Denmark)

    Kingod, Natasja; Cleal, Bryan; Wahlberg, Ayo

    2017-01-01

    This qualitative systematic review investigated how individuals with chronic illness experience online peer-to-peer support and how their experiences influence daily life with illness. Selected studies were appraised by quality criteria focused upon research questions and study design, participant...... provide a supportive space for daily self-care related to chronic illness. Online communities provided a valued space to strengthen social ties and exchange knowledge that supported offline ties and patient–doctor relationships. Individuals used online communities to exchange experiential knowledge about...... selection, methods of data collection, and methods of analysis. Four themes were identified: (a) illness-associated identity work, (b) social support and connectivity, (c) experiential knowledge sharing, and (d) collective voice and mobilization. Findings indicate that online peer-to-peer communities...

  8. Changing the meaning of peer-to-peer? Exploring online comment spaces as sites of negotiated expertise

    Directory of Open Access Journals (Sweden)

    Marie-Claire Shanahan

    2010-02-01

    Full Text Available This study examines the nature of peer-to-peer interactions in public online comment spaces. From a theoretical perspective of boundary-work and expertise, the comments posted in response to three health sciences news articles from a national newspaper are explored to determine whether both scientific and personal expertise are recognized and taken up in discussion. Posts were analysed for both explicit claims to expertise and implicit claims embedded in discourse. The analysis suggests that while both scientific and personal expertise are proffered by commenters, it is scientific expertise that is privileged. Those expressing scientific expertise receive greater recognition of the value of their posts. Contributors seeking to share personal expertise are found to engage in scientisation to position themselves as worthwhile experts. Findings suggest that despite the possibilities afforded by online comments for a broader vision of what peer-to-peer interaction means, this possibility is not realized.

  9. Effects of script training on the peer-to-peer communication of children with autism spectrum disorder.

    Science.gov (United States)

    Ledbetter-Cho, Katherine; Lang, Russell; Davenport, Katy; Moore, Melissa; Lee, Allyson; Howell, Alexandria; Drew, Christine; Dawson, Dana; Charlop, Marjorie H; Falcomata, Terry; O'Reilly, Mark

    2015-12-01

    A multiple baseline design across participants was used to demonstrate the effects of a script-training procedure on the peer-to-peer communication of 3 children with autism spectrum disorder during group play with peers. Both scripted and unscripted initiations as well as responses to peers increased for all 3 participants. Stimulus generalization across novel toys, settings, and peers was observed. Novel unscripted initiations, responses, and appropriate changes in topics during peer-to-peer exchanges were analyzed by considering the cumulative frequency of these behaviors across phases of the study. Treatment gains were maintained during 4-week follow-up sessions. Results are discussed in terms of recommendations for practitioners, response variability, and potential future avenues of research. © Society for the Experimental Analysis of Behavior.

  10. Cyberbullying or Cyber Aggression?: A Review of Existing Definitions of Cyber-Based Peer-to-Peer Aggression

    OpenAIRE

    Lucie Corcoran; Conor Mc Guckin; Garry Prentice

    2015-01-01

    Due to the ongoing debate regarding the definitions and measurement of cyberbullying, the present article critically appraises the existing literature and offers direction regarding the question of how best to conceptualise peer-to-peer abuse in a cyber context. Variations across definitions are problematic as it has been argued that inconsistencies with regard to definitions result in researchers examining different phenomena, whilst the absence of an agreed conceptualisation of the behaviou...

  11. Open-source Peer-to-Peer Environment to Enable Sensor Web Architecture: Application to Geomagnetic Observations and Modeling

    Science.gov (United States)

    Holland, M.; Pulkkinen, A.

    2007-12-01

    A flexible, dynamic, and reliable secure peer-to-peer (P2P) communication environment is under development at NASA's Goddard Space Flight Center (GSFC). Popular open-source P2P software technology provides a self- organizing, self-healing ad hoc "virtual network overlay" protocol-suite. The current effort builds a proof-of-concept geomagnetic Sensor Web upon this foundation. Our long-term objective is to enable an evolution of many types of distributed Earth system sensors and related processing/storage components into elements of an operational Sensor Web via integration into this P2P Environment. In general, the Environment distributes data communication tasks among the sensors (viewed as peers, each assigned a peer-role) and controls the flow of data. This work encompasses dynamic discovery, monitoring, control, and configuration as well as autonomous operations, real-time modeling and data processing, and secure ubiquitous communications. We currently restrict our communications to be within the secure GSFC network environment, and have integrated "simulated" (via historical data) geomagnetic sensors. Each remote sensor has operating modes to manage (from remote interfaces) and is designed to have features nearly indistinguishable from a live magnetometer. We have implemented basic identity management features (organized around GSFC identity-management practices); providing mechanisms which restrict data-serving privileges to authorized users, and which allow improved trust and accountability among users of the Environment. Data-serving peers digitally "sign" their services, and their data-browsing counterparts will only accept the products of services whose signature (and hence identity) can be verified. The current usage scenario involves modeling-peers, which operate within the same Environment as the sensors and also have operating modes to remotely manage, portraying a near-real- time global representation of geomagnetic activity from dynamic sensor

  12. Peer-to-Peer Consultations: Ancillary Services Peer Exchange with India: Experience from South Africa, Europe & the United States (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-05-01

    In support of national and subnational decision makers, the 21st Century Power Partnership regularly works with country partners to organize peer-to-peer consultations on critical issues. In March 2014, 21CPP collaborated with the Regulatory Assistance Project - India to host two peer-to-peer exchanges among experts from India, South Africa, Europe, and the United States to discuss the provision of ancillary services, particularly in the context of added variability and uncertainty from renewable energy. This factsheet provides a high level summary of the peer-to-peer consultation.

  13. Le Peer to Peer: Vers un Nouveau Modèle de Civilization

    Directory of Open Access Journals (Sweden)

    Michel Bauwens

    2006-06-01

    Full Text Available Le « peer to peer » est la dynamique intersubjective caractéristique des réseaux distribués. Le but de cet essai est de montrer qu'il s'agit d'une véritable nouvelle forme d’organisation sociale, apte à produire et échanger des biens, à créer de la valeur. Celle-ci est la conséquence d'un nouvel imaginaire social, et possède le potentiel de devenir le pilier d'un nouveau mode d'économie politique, voire d'un nouveau type de civilisation. Pour cela, nous allons d'abord définir le P2P, décrire en bref ces manifestations, et le différencier d'autres modalités d'échange intersubjectif tel que le marché, la hiérarchie, l'économie du don.Comme principale modalité P2P nous distinguons: Les processus de production P2P, comme troisième mode de production, qui n'est ni géré par un mode hiérarchique ou par l'état, ni répondant à des impératifs de profit ou qui sont modulés par le biais des prix. Les processus de gouvernance P2P, qui gouverne ces processus de production. Les formes de propriété P2P, qui sont destine a empecher l’appropriation prive de cette production pour le commun.Afin d’examiner les characteristiques de cette nouvelle dynamique sociale, nous utilisons la typologie intersubjective de l’anthropologue Alan Page Fisque, qui distingue: 1. l'échange égalitaire (Equality Matching, c..a.d l’economie du don. 2. La relation d’autorité (Authority Ranking tel qu’elle s’exprime dans le mode hierarchique. 3. le marché (Market Pricing. 4. la participation commune (Communal Shareholding.En conclusion, nous examinons les possibilites d’expansion de ce nouveau mode sociale et son insertion dans l’economie capitaliste, en nous nous posons la question: le P2P peut-il etre concu comme alternative sociale et economique aux modeles existants.

  14. A MULTI ATTRIBUTE RANKING MECHANISM FOR PEER-TO-PEER NETWORKS

    Directory of Open Access Journals (Sweden)

    B. Swaminathan

    2014-01-01

    Full Text Available P2P systems are envisioned to play a greater role in collaborative applications. P2P environments remove the challenging task of using servers for information sharing. Emerging collaborative P2P systems require discovery and utilization of multi-attribute, distributed and dynamic group of resources to achieve greater tasks beyond conventional file and processor cycle sharing. The process of selection of a peer for collaborative work therefore plays a significant role in accomplishing the task. Collaborative P2P systems use a group of diverse resources like hardware, software, services and data to accomplish the task or application. Hence, ranking of peers based on multiple heterogeneous attributes plays a significant role in enabling the selection of the right peers for collaboration. This study proposes the use of Analytic Hierarchy Process (AHP for ranking the peers for selection. The relative importance of the attributes has to be decided based on the P2P application that is being collaborated. AHP provides the mathematical technique for decision making for ranking the peers for collaborative activity. The application of AHP for peer ranking has been illustrated with the use of examples. The system has been implemented and tested using Planet Lab dataset. The selection of right peer using this method has improved the process of multi attribute decision making and an optimal decision has been obtained by mapping the requirements to the available resources. The number of criteria used for P2P collaboration has been varied and the results observed shows that the decision making time increases proportional to the number of criteria.

  15. Global Phenomena from Local Rules: Peer-to-Peer Networks and Crystal Steps

    Science.gov (United States)

    2007-01-01

    degree of Doctor of Philosophy 2007 Advisory Committee: Professor James Yorke, Chair/Advisor Professor Brian Hunt, Co-Advisor Professor Dionisios Margetis...Massachusetts, USA, June 2007. [62] Pak-Wing Fok, Rodolfo R. Rosales, and Dionisios Margetis. Unification of step bunching phenomena on vicinal...vicinal substrates. Physical Review Letters, 89(6):1268–1271, February 1998. [73] Dionisios Margetis, Michael J. Aziz, and Howard A. Stone. Continuum

  16. A Local Distributed Peer-to-Peer Algorithm Using Multi-Party Optimization Based Privacy Preservation for Data Mining Primitive Computation

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper proposes a scalable, local privacy-preserving algorithm for distributed peer-to-peer (P2P) data aggregation useful for many advanced data mining/analysis...

  17. Beauty premium: Event-related potentials evidence of how physical attractiveness matters in online peer-to-peer lending.

    Science.gov (United States)

    Jin, Jia; Fan, Bonai; Dai, Shenyi; Ma, Qingguo

    2017-02-15

    Although it is well known that attractiveness-based impressions affect the labor market, election outcomes and many other social activities, little is known about the role physical attractiveness plays in financial transactions. With the development of online finance, peer-to-peer lending has become one of the most important ways in which businesses or individuals raise capital. However, because of information asymmetry, the lender must decide whether or not to lend money to a stranger based on limited information, resulting in their decision being influenced by many other factors. In the current study, we investigated how potential borrowers' facial attractiveness influenced lenders' attitudes toward borrowers' repayment behavior at the brain level by using event-related potentials. At the priming stage, photos of attractive borrowers induced smaller N200 amplitude than photos of unattractive borrowers. Meanwhile, at the feedback stage, compared with the condition of repaying on time, breach of repayment from unattractive borrowers induced larger feedback-related negativity (FRN) amplitude, which was a frontal-central negative deflection and would be enhanced by the unexpected outcome. Furthermore, smaller P300 amplitude was also elicited by the condition of not repaying on time. These differences in the FRN and P300 amplitudes were not observed between negative and positive feedback from attractive borrowers. Therefore, our findings suggest that the beauty premium phenomenon is present in online peer-to-peer lending and that lenders were more tolerant toward attractive borrowers' dishonest behavior.

  18. PENERAPAN METODE PRINCIPAL COMPONENT ANALYSIS (PCA UNTUK DETEKSI ANOMALI PADA JARINGAN PEER-TO-PEER (P2P BOTNET

    Directory of Open Access Journals (Sweden)

    Adhitya Nugraha

    2015-10-01

    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

  19. An agent-based peer-to-peer architecture for semantic discovery of manufacturing services across virtual enterprises

    Science.gov (United States)

    Zhang, Wenyu; Zhang, Shuai; Cai, Ming; Jian, Wu

    2015-04-01

    With the development of virtual enterprise (VE) paradigm, the usage of serviceoriented architecture (SOA) is increasingly being considered for facilitating the integration and utilisation of distributed manufacturing resources. However, due to the heterogeneous nature among VEs, the dynamic nature of a VE and the autonomous nature of each VE member, the lack of both sophisticated coordination mechanism in the popular centralised infrastructure and semantic expressivity in the existing SOA standards make the current centralised, syntactic service discovery method undesirable. This motivates the proposed agent-based peer-to-peer (P2P) architecture for semantic discovery of manufacturing services across VEs. Multi-agent technology provides autonomous and flexible problemsolving capabilities in dynamic and adaptive VE environments. Peer-to-peer overlay provides highly scalable coupling across decentralised VEs, each of which exhibiting as a peer composed of multiple agents dealing with manufacturing services. The proposed architecture utilises a novel, efficient, two-stage search strategy - semantic peer discovery and semantic service discovery - to handle the complex searches of manufacturing services across VEs through fast peer filtering. The operation and experimental evaluation of the prototype system are presented to validate the implementation of the proposed approach.

  20. An Optimal Mobile Service for Telecare Data Synchronization using a Role-based Access Control Model and Mobile Peer-to-Peer Technology.

    Science.gov (United States)

    Ke, Chih-Kun; Lin, Zheng-Hua

    2015-09-01

    The progress of information and communication technologies (ICT) has promoted the development of healthcare which has enabled the exchange of resources and services between organizations. Organizations want to integrate mobile devices into their hospital information systems (HIS) due to the convenience to employees who are then able to perform specific healthcare processes from any location. The collection and merage of healthcare data from discrete mobile devices are worth exploring possible ways for further use, especially in remote districts without public data network (PDN) to connect the HIS. In this study, we propose an optimal mobile service which automatically synchronizes the telecare file resources among discrete mobile devices. The proposed service enforces some technical methods. The role-based access control model defines the telecare file resources accessing mechanism; the symmetric data encryption method protects telecare file resources transmitted over a mobile peer-to-peer network. The multi-criteria decision analysis method, ELECTRE (Elimination Et Choice Translating Reality), evaluates multiple criteria of the candidates' mobile devices to determine a ranking order. This optimizes the synchronization of telecare file resources among discrete mobile devices. A prototype system is implemented to examine the proposed mobile service. The results of the experiment show that the proposed mobile service can automatically and effectively synchronize telecare file resources among discrete mobile devices. The contribution of this experiment is to provide an optimal mobile service that enhances the security of telecare file resource synchronization and strengthens an organization's mobility.

  1. Adult Willingness to Use Email and Social Media for Peer-to-Peer Cancer Screening Communication: Quantitative Interview Study.

    Science.gov (United States)

    Cutrona, Sarah L; Roblin, Douglas W; Wagner, Joann L; Gaglio, Bridget; Williams, Andrew E; Torres Stone, Rosalie; Field, Terry S; Mazor, Kathleen M

    2013-11-28

    Adults over age 40 are increasing their use of email and social media, raising interest in use of peer-to-peer Internet-based messaging to promote cancer screening. The objective of our study was to assess current practices and attitudes toward use of email and other e-communication for peer-to-peer dialogues on cancer screening. We conducted in-person interviews with 438 insured adults ages 42-73 in Georgia, Hawaii, and Massachusetts. Participants reported on use of email and other e-communication including social media to discuss with peers routine health topics including breast and colorectal cancer (CRC). We ascertained willingness to share personal CRC screening experiences via conversation, postcard, email, or other e-communication. Health literacy scores were measured. Email had been used by one-third (33.8%, 148/438) to discuss routine health topics, by 14.6% (64/438) to discuss breast cancer screening, and by 12.6% (55/438) to discuss CRC screening. Other e-communication was used to discuss routine health topics (11.6%, 51/438), screening for breast cancer (3.9%, 17/438), and CRC (2.3%, 10/438). In the preceding week, 84.5% (370/438) of participants had used email, 55.9% (245/438) had used e-communication of some type; 44.3% (194/438) text, 32.9% (144/438) Facebook, 12.3% (54/438) instant message, 7.1% (31/438) video chat, and 4.8% (21/438) Twitter. Many participants were willing to share their CRC screening experiences via email (32.4%, 142/438 might be willing; 36.3%, 159/438 very willing) and via other e-communication (15.8%, 69/438 might be willing; 14.4%, 63/438 very willing). Individuals willing to send CRC screening emails scored significantly higher on tests of health literacy compared to those willing to send only postcards (Pcommunication to promote cancer screening to peers. Optimal approaches for encouraging peer-to-peer transmission of accurate and appropriate cancer screening messages must be studied.

  2. Searching for help online: An analysis of peer-to-peer posts on a male-only infertility forum.

    Science.gov (United States)

    Hanna, Esmée; Gough, Brendan

    2016-04-22

    Men's experiences of infertility help seeking are under-researched and thus less widely understood than women's experiences, with men's needs for support often missing from reproductive research knowledge. This article presents a thematic analysis of peer-to-peer posts within the context of a UK men-only online infertility forum. The key themes demonstrate that men value male support from those with experience, and that masculinity influences help-seeking requests and men's accounts more broadly. We highlight the value of such online communities in offering support to men in need while recognising the importance of further research across other online settings in order to inform practice around supporting men in the reproductive realm.

  3. Agentes Peer-To-Peer Baseados Em Ontologias Como Mediadores Em Processos Comunitários De Partilha E Aprendizagem

    Directory of Open Access Journals (Sweden)

    G. A. Giménez-Lugo

    2009-06-01

    Full Text Available Este artigo tenta realçar a importância do desenvolvimento de sistemas voltados ao aprendizado baseados em agentes inteligentes estruturados como sistemas P2P (peer-to-peer – entre pares. Como parte deste esforço é apresentado um modelo no qual conceitos pertencentes a ontologias são estendidos com informação organizacional para representar de forma explícita as situações sociais nas quais foram aprendidas e utilizadas. Uma aplicação P2P usando o modelo é descrita. Parte-se de um modelo organizacional específico, MOISE+, brevemente apresentado. Uma ponte sócio-organizacional poderá agora auxiliar a interligar e reconciliar visões diferentes de conhecimento para facilitar o aprendizado coletivo.

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

    CERN Multimedia

    2003-01-01

    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: http://cern.ch/security/file-sharing CERN's Computing Rules are at: http://cern.ch/ComputingRules Denise Heagerty, CERN Computer Security Officer, Computer.Security@cern.ch

  5. An Online, Moderated Peer-to-Peer Support Bulletin Board for Depression: User-Perceived Advantages and Disadvantages

    Science.gov (United States)

    Reynolds, Julia; Vassallo, Sara

    2015-01-01

    Background Online, peer-to-peer support groups for depression are common on the World Wide Web and there is some evidence of their effectiveness. However, little is known about the mechanisms by which Internet support groups (ISGs) might work. Objective This study aimed to investigate consumer perceptions of the benefits and disadvantages of online peer-to-peer support by undertaking a content analysis of the spontaneous posts on BlueBoard, a well-established, moderated, online depression bulletin board. Methods The research set comprised all posts on the board (n=3645) for each of 3 months selected at 4 monthly intervals over 2011. The data were analyzed using content analysis and multiple coders. Results A total of 586 relevant posts were identified, 453 (77.3%) reporting advantages and 133 (22.7%) reporting disadvantages. Positive personal change (335/453, 74.0%) and valued social interactions and support (296/453, 65.3%) emerged as perceived advantages. Other identified benefits were valued opportunities to disclose/express feelings or views (29/453, 6.4%) and advantages of the BlueBoard environment (45/453, 9.9%). Disadvantages were negative personal change (50/133, 37.6%), perceived disadvantages of board rules/moderation (42/133, 31.6%), unhelpful social interactions/contact with other members (40/133, 30.1%), and technical obstacles to using the board (14/133, 10.5%). Conclusions Consumers value the opportunity to participate in an online mutual support group for mental health concerns. Further research is required to better understand how and if these perceived advantages translate into positive outcomes for consumers, and whether the perceived disadvantages of such boards can be addressed without compromising the safety and positive outcomes of the board. PMID:26543919

  6. A Robust Distributed Reputation Mechanism for Peer-to-Peer Systems

    NARCIS (Netherlands)

    Delaviz Aghbolagh, R.

    2013-01-01

    In P2P content distribution networks, incentive mechanisms are required for sustainable operation of the network. In general, there are two classes of incentive mechanisms, direct and indirect. In direct mechanisms, a content consumer compensates the work of a supplier by providing him some content

  7. A Robust Distributed Reputation Mechanism for Peer-to-Peer Systems

    NARCIS (Netherlands)

    Delaviz Aghbolagh, R.

    2013-01-01

    In P2P content distribution networks, incentive mechanisms are required for sustainable operation of the network. In general, there are two classes of incentive mechanisms, direct and indirect. In direct mechanisms, a content consumer compensates the work of a supplier by providing him some content

  8. Local L2 Thresholding Based Data Mining in Peer-to-Peer Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — In a large network of computers, wireless sensors, or mobile devices, each of the components (hence, peers) has some data about the global status of the system. Many...

  9. Mobile Based Secure Digital Wallet for Peer to Peer Payment System

    CERN Document Server

    Taghiloo, Majid; Rezaeinezhad, Mohammad Reza

    2010-01-01

    E-commerce in today's conditions has the highest dependence on network infrastructure of banking. However, when the possibility of communicating with the Banking network is not provided, business activities will suffer. This paper proposes a new approach of digital wallet based on mobile devices without the need to exchange physical money or communicate with banking network. A digital wallet is a software component that allows a user to make an electronic payment in cash (such as a credit card or a digital coin), and hides the low-level details of executing the payment protocol that is used to make the payment. The main features of proposed architecture are secure awareness, fault tolerance, and infrastructure-less protocol.

  10. MOBILE BASED SECURE DIGITAL WALLET FOR PEER TO PEER PAYMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    Majid Taghiloo

    2010-11-01

    Full Text Available E-commerce in today's conditions has the highest dependence on network infrastructure of banking.However, when the possibility of communicating with the Banking network is not provided, businessactivities will suffer. This paper proposes a new approach of digital wallet based on mobile deviceswithout the need to exchange physical money or communicate with banking network. A digital wallet is asoftware component that allows a user to make an electronic payment in cash (such as a credit card or adigital coin, and hides the low-level details of executing the payment protocol that is used to make thepayment. The main features of proposed architecture are secure awareness, fault tolerance, andinfrastructure-less protocol.

  11. OpenWeather: a peer-to-peer weather data transmission protocol

    CERN Document Server

    Yanes, Adrian

    2011-01-01

    The study of the weather is performed using instruments termed weather stations. These weather stations are distributed around the world, collecting the data from the different phenomena. Several weather organizations have been deploying thousands of these instruments, creating big networks to collect weather data. These instruments are collecting the weather data and delivering it for later processing in the collections points. Nevertheless, all the methodologies used to transmit the weather data are based in protocols non adapted for this purpose. Thus, the weather stations are limited by the data formats and protocols used in them, not taking advantage of the real-time data available on them. We research the weather instruments, their technology and their network capabilities, in order to provide a solution for the mentioned problem. OpenWeather is the protocol proposed to provide a more optimum and reliable way to transmit the weather data. We evaluate the environmental factors, such as location or bandwi...

  12. Design Issues and Challenges of Peer-to-Peer Video on Demand System

    OpenAIRE

    Hareesh.K; Manjaiah D.H .

    2011-01-01

    P2P media streaming and file downloading is most popular applications over the Internet. These systems reduce the server load and provide a scalable content distribution. P2P networking is a new paradigm to build distributed applications. It describes the design requirements for P2P media streaming, live and Video on demand system comparison based on their system architecture. In this paper we described and studied the traditional approaches for P2P streaming systems, design is...

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

    Directory of Open Access Journals (Sweden)

    Ken Kerpez

    2010-01-01

    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.

  14. Resource Search in Unstructured Peer-to-Peer System Based on Multiple-Tree Overlay Structure

    Institute of Scientific and Technical Information of China (English)

    YU Jianqiao; LIAO Jianwei

    2007-01-01

    We propose a multiple-tree overlay structure for resource discovery in unstructured P2P systems. Peers that have similar interests or hold similar type of resources will be grouped into a tree-like cluster. We exploit the heterogeneity of peers in each cluster by connecting peers with more capacities closer to the root of the tree. The capacity of a peer can be defined in different ways (e.g. higher network bandwidth, larger disk space, more data items of a certain type etc.) according to different needs of users or applications.

  15. Study on the Distributed Routing Algorithm and Its Security for Peer-to-Peer Computing

    Institute of Scientific and Technical Information of China (English)

    ZHOU Shi-jie

    2005-01-01

    @@ By virtue of its great efficiency and graceful architecture, the Client/Server model has been prevalent for more than twenty years, but some disadvantages are also recognized. It is not so suitable for the next generation Internet (NGI), which will provide a high-speed communication platform. Especially, the service bottleneck of Client/Server model will become more and more severe in such high-speed networking environment. Some approaches have been proposed to solve such kind of disadvantages. Among these, distributed computing is considered an important candidate for Client/Server model.

  16. "I'm Not Here to Learn How to Mark Someone Else's Stuff": An Investigation of an Online Peer-to-Peer Review Workshop Tool

    Science.gov (United States)

    Wilson, Michael John; Diao, Ming Ming; Huang, Leon

    2015-01-01

    In this article, we explore the intersecting concepts of fairness, trust and temporality in relation to the implementation of an online peer-to-peer review Moodle Workshop tool at a Sydney metropolitan university. Drawing on qualitative interviews with unit convenors and online surveys of students using the Workshop tool, we seek to highlight a…

  17. Secure SMS Mobile Transaction with Peer to Peer Authentication Design for Mobile Government

    Directory of Open Access Journals (Sweden)

    Mohammad Khalaf Rahim Al-juaifari

    2015-11-01

    Full Text Available Currently, many researches in Mobile government secure transmission of plaintext with universal availability in all GSM networks had been proposed. The most important characteristic of this research is a new system that contains all the capabilities and plugging security holes in the algorithms and methods used in previous systems design. The main reason of the intensification of efforts for the purpose of security in a mobile government is the real threat that accompanies the movement of transaction from the sender to the recipient. Moreover, mobile government used in improving convenience is one the clearest manifestations of the development of society and solving various problems using other method related to availability, speed, financial, in addition to the administrative issues related to the fight against corruption side a side with Egovernment. In this paper, illustrating how a mobile phone can provide citizens and Non-government organizations with mobile government services relevant to the design and implementation of security mechanisms coinciding with the birth of the third generation technology in Iraq so as to ensure the highest level of security transaction provided by UMTS security is also built upon GSM network.

  18. Using Social Media to Expand Peer-to-Peer Discussion in an Online Course about Regional Climate Modeling

    Science.gov (United States)

    Yarker, M. B.; Mesquita, M. D. S.

    2015-12-01

    The goal of this project is to make knowledge about regional climate modeling accessible to anyone in any location, regardless of their resources. We accomplish this through the development of a free online course, which introduces novice model users to an educational version of the Weather Research and Forecasting model (e-WRF). These courses are grounded in education theory and have been described in detail at prior AGU meetings (Kelsey et al. 2014, Walton et al. 2014, Yarker & Mesquita 2013). Research indicates that effective dialogue is an important component for successful learning to occur and displays the following elements: asking complex questions, deep discussion, and use of evidence to construct arguments (Benus et al. 2013). These can happen between the student and tutor, but peer-to-peer interaction is especially important as well as the most difficult aspect of social constructivism to meet, especially in an online setting. In our online courses, standard course forums were underutilized and generally only used to ask the tutor clarifying questions or troubleshoot error messages. To rectify this problem, we began using social media to facilitate conversation and notice vast improvement in peer-to-peer communication. Moreover, we created a community of over 700 regional climate modelers from around the world, sharing information, asking questions, and creating research projects relating to climate change. Data was gathered by qualitatively analyzing forum and Facebook posts and quantitatively analyzing survey data from participants in both courses. Facebook participants posted on the group more often about a wider variety of topics than the forum participants. Additionally, there were statistically significant increase ('student' t test and Mann-Whitney test) in the elements of effective dialogue. We conclude that social media can serve as a possible tool in the development of online learning, especially for difficult concepts like regional climate

  19. MO-E-18C-01: Open Access Web-Based Peer-To-Peer Training and Education in Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Pawlicki, T [UC San Diego Medical Center, La Jolla, CA (United States); Brown, D; Dunscombe, P [Tom Baker Cancer Centre, Calgary, AB (Canada); Mutic, S [Washington University School of Medicine, Saint Louis, MO (United States)

    2014-06-15

    Purpose: Current training and education delivery models have limitations which result in gaps in clinical proficiency with equipment, procedures, and techniques. Educational and training opportunities offered by vendors and professional societies are by their nature not available at point of need or for the life of clinical systems. The objective of this work is to leverage modern communications technology to provide peer-to-peer training and education for radiotherapy professionals, in the clinic and on demand, as they undertake their clinical duties. Methods: We have developed a free of charge web site ( https://i.treatsafely.org ) using the Google App Engine and datastore (NDB, GQL), Python with AJAX-RPC, and Javascript. The site is a radiotherapy-specific hosting service to which user-created videos illustrating clinical or physics processes and other relevant educational material can be uploaded. Efficient navigation to the material of interest is provided through several RT specific search tools and videos can be scored by users, thus providing comprehensive peer review of the site content. The site also supports multilingual narration\\translation of videos, a quiz function for competence assessment and a library function allowing groups or institutions to define their standard operating procedures based on the video content. Results: The website went live in August 2013 and currently has over 680 registered users from 55 countries; 27.2% from the United States, 9.8% from India, 8.3% from the United Kingdom, 7.3% from Brazil, and 47.5% from other countries. The users include physicists (57.4%), Oncologists (12.5%), therapists (8.2%) and dosimetrists (4.8%). There are 75 videos to date including English, Portuguese, Mandarin, and Thai. Conclusion: Based on the initial acceptance of the site, we conclude that this open access web-based peer-to-peer tool is fulfilling an important need in radiotherapy training and education. Site functionality should expand in

  20. The pragmatic language abilities of children with ADHD following a play-based intervention involving peer-to-peer interactions.

    Science.gov (United States)

    Cordier, Reinie; Munro, Natalie; Wilkes-Gillan, Sarah; Docking, Kimberley

    2013-08-01

    Children with Attention Deficit Hyperactivity Disorder (ADHD) commonly experience significant pragmatic language deficits which put them at risk of developing emotional and social difficulties. This study aimed to examine the pragmatic language exhibited in a peer-to-peer interaction between the children with ADHD and their playmates following a pilot play-based intervention. Participants were children (aged 5-11 years) diagnosed as having ADHD (n = 14) and their self-selected typically-developing playmate. Pragmatic language was measured using the Pragmatic Protocol (PP) and the Structured Multidimensional Assessment Profiles (S-MAPs). Children's structural language was also screened and compared against their pragmatic language skills pre-post play-based intervention. The pragmatic language of children with ADHD improved significantly from pre-post intervention as measured by both the PP and S-MAPs. Both children with and without structural language difficulties improved significantly from pre- to post-intervention using S-MAPs; only children with structural language difficulties improved significantly using PP. The findings support the notion that pragmatic skills may improve following a play-based intervention that is characterized by didactic social interaction. As pragmatic language is a complex construct, it is proposed that clinicians and researchers reconsider the working definition of pragmatic language and the operationalization thereof in assessments.

  1. AbIx: An Approach to Content-Based Approximate Query Processing in Peer-to-Peer Data Systems

    Institute of Scientific and Technical Information of China (English)

    Chao-Kun Wang; Jian-Min Wang; Jia-Guang Sun; Sheng-Fei Shi; Hong Gao

    2007-01-01

    In recent years there has been a significant interest in peer-to-peer (P2P) environments in the community ofdata management. However, almost all work, so far, is focused on exact query processing in current P2P data systems.The autonomy of peers also is not considered enough. In addition, the system cost is very high because the informationpublishing method of shared data is based on each document instead of document set. In this paper, abstract indices (AbIx)are presented to implement content-based approximate queries in centralized, distributed and structured P2P data systems.It can be used to search as few peers as possible but get as many returns satisfying users' queries as possible on the guaranteeof high autonomy of peers. Also, abstract indices have low system cost, can improve the query processing speed, and supportvery frequent updates and the set information publishing method. In order to verify the effectiveness of abstract indices, asimulator of 10,000 peers, over 3 million documents is made, and several metrics are proposed. The experimental results showthat abstract indices work well in various P2P data systems.

  2. Cyberbullying or Cyber Aggression?: A Review of Existing Definitions of Cyber-Based Peer-to-Peer Aggression

    Directory of Open Access Journals (Sweden)

    Lucie Corcoran

    2015-03-01

    Full Text Available Due to the ongoing debate regarding the definitions and measurement of cyberbullying, the present article critically appraises the existing literature and offers direction regarding the question of how best to conceptualise peer-to-peer abuse in a cyber context. Variations across definitions are problematic as it has been argued that inconsistencies with regard to definitions result in researchers examining different phenomena, whilst the absence of an agreed conceptualisation of the behaviour(s involved hinders the development of reliable and valid measures. Existing definitions of cyberbullying often incorporate the criteria of traditional bullying such as intent to harm, repetition, and imbalance of power. However, due to the unique nature of cyber-based communication, it can be difficult to identify such criteria in relation to cyber-based abuse. Thus, for these reasons cyberbullying may not be the most appropriate term. Rather than attempting to “shoe-horn” this abusive behaviour into the preconceived conceptual framework that provides an understanding of traditional bullying, it is timely to take an alternative approach. We argue that it is now time to turn our attention to the broader issue of cyber aggression, rather than persist with the narrow focus that is cyberbullying.

  3. Employing peer-to-peer software distribution in ALICE Grid Services to enable opportunistic use of OSG resources

    CERN Document Server

    CERN. Geneva; Sakrejda, Iwona

    2012-01-01

    The ALICE Grid infrastructure is based on AliEn, a lightweight open source framework built on Web Services and a Distributed Agent Model in which job agents are submitted onto a grid site to prepare the environment and pull work from a central task queue located at CERN. In the standard configuration, each ALICE grid site supports an ALICE-specific VO box as a single point of contact between the site and the ALICE central services. VO box processes monitor site utilization and job requests (ClusterMonitor), monitor dynamic job and site properties (MonaLisa), perform job agent submission (CE) and deploy job-specific software (PackMan). In particular, requiring a VO box at each site simplifies deployment of job software, done onto a shared file system at the site, and adds redundancy to the overall Grid system. ALICE offline computing, however, has also implemented a peer-to-peer method (based on BitTorrent) for downloading job software directly onto each worker node as needed. By utilizing both this peer-...

  4. A Cost-Effective Peer-to-Peer Architecture for Large-Scale On-Demand Media Streaming

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2006-05-01

    Full Text Available This paper presents a cost-effective peer-to-peer (P2P architecture for large-scale on-demand media streaming, named BitVampire. BitVampire’s primary design goal is to aggregate peers’ storage and upstream bandwidth to facilitate on-demand media streaming. To achieve this goal, BitVampire splits published videos into segments and distributes them to different peers. When a peer (or a receiver wants to watch a video, it (i searches the corresponding segments, then (ii selfishly determines the best subset of supplying peers and (iii aggregates bandwidth from these peers to stream the media content. In BitVampire, participating peers help each other to get the desired media content, thus powerful servers/proxies are not necessary, which makes it a cost- effective approach. To demonstrate the effectiveness of BitVampire, we conducted extensive simulation on large, hierarchical, Internet-like topologies. We also implemented a functional prototype using Java and Java Media Framework (JMF to demonstrate the feasibility of BitVampire.

  5. Applications of Coding in Network Communications

    Science.gov (United States)

    Chang, Christopher SungWook

    2012-01-01

    This thesis uses the tool of network coding to investigate fast peer-to-peer file distribution, anonymous communication, robust network construction under uncertainty, and prioritized transmission. In a peer-to-peer file distribution system, we use a linear optimization approach to show that the network coding framework significantly simplifies…

  6. Performance Analysis of Hybrid Distribution in Human-Centric Multimedia Networking

    Institute of Scientific and Technical Information of China (English)

    HU Yuxiang; DONG Fang; LAN Julong

    2016-01-01

    With the booming of Human-centric mul-timedia networking (HMN), there are rising amount of human-made multimedia that needs to distribute to con-sumers with higher speed and efficiency. Hybrid distribu-tion of Client/Server (C/S) and Peer-to-Peer (P2P) have been successfully deployed on the Internet and the practi-cal benefits have been widely reported, while its theoretical performance remains unknown for mass data delivery un-fortunately. This paper presents an analytical and experi-mental study on the performance of accelerating large-scale hybrid distribution over the Internet. In particular, this pa-per focuses on the user behavior in HMN and establishes a user behavior model based on the Kermack-McKendrick model in epidemiology. Analytical expressions of average delay in HMN are then derived based on C/S, P2P and hy-brid distribution, respectively. Our simulation shows how to design and deploy a hybrid distribution system of HMN that helps to bridge the gap between system ultilization and quality of service, which provides direct guidance for practical system design.

  7. Peer to Peer

    Science.gov (United States)

    Brown, Stephanie Willen; Hammond, Chelsea C.

    2008-01-01

    This article reports that the Scopus Student Ambassador (SAm) program, funded by Elsevier, permitted the University of Connecticut (UConn) Libraries to hire graduate students to teach citation searching, using both Scopus and Web of Science, to other graduate students. The training does not cost the libraries anything, and it is free for graduate…

  8. Peer to Peer

    Science.gov (United States)

    Brown, Stephanie Willen; Hammond, Chelsea C.

    2008-01-01

    This article reports that the Scopus Student Ambassador (SAm) program, funded by Elsevier, permitted the University of Connecticut (UConn) Libraries to hire graduate students to teach citation searching, using both Scopus and Web of Science, to other graduate students. The training does not cost the libraries anything, and it is free for graduate…

  9. The Effect of Electronic Word of Mouth on Intention to Book Accommodation via Online Peer-to-Peer Platform: Investigation of Theory of Planned Behaviour

    Directory of Open Access Journals (Sweden)

    See-Kwong Goh

    2016-01-01

    Full Text Available The main purpose for conducting the research is to investigate whether positive eWOM received by consumers would influence their intention to book accommodation via a peer-to-peer website or mobile phone apps (such as Airbnb. The research was conducted by utilizing the Theory of Planned Behaviour which integrates the eWOM, attitude, subjective norms, perceived behavioural control and behavioural intention. A total of 226 responses had been recorded. The main findings from this research are related to the key role played by positive eWOM received towards an individual’s attitude, subjective norm and perceived behavioural control which influences their intention to book their accommodation through an online peer-to-peer platform.

  10. Sexual and reproductive health in Greenland: evaluation of implementing sexual peer-to-peer education in Greenland (the SexInuk project).

    Science.gov (United States)

    Homøe, Anne-Sophie; Knudsen, Ane-Kersti Skaarup; Nielsen, Sigrid Brisson; Grynnerup, Anna Garcia-Alix

    2015-01-01

    For decades, the rates of sexually transmitted infections (STIs), such as gonorrhoea, chlamydia and syphilis, have increased in Greenland, especially within the young age groups (15-29 years). From 2006 to 2013, the number of abortions has been consistent with approximately 800-900 abortions per year in Greenland, which is nearly as high as the total number of births during the same period. Previous studies in Greenland have reported that knowledge about sexual health is important, both as prevention and as facilitator to stop the increasing rates of STIs. A peer-to-peer education programme about sexual health requires adaption to cultural values and acceptance among the population and government in order to be sustainable. Formative evaluation of a voluntary project (SexInuk), in relation to peer-to-peer education with focus on sexual health. Two workshops were conducted in Nuuk, Greenland, to recruit Greenlandic students. Qualitative design with focus group interviews (FGIs) to collect qualitative feedback on feasibility and implementation of the project. Supplemented with a brief questionnaire regarding personal information (gender, age, education) and questions about the educational elements in the SexInuk project. Eight Greenlandic students, who had completed one or two workshops, were enrolled. The FGIs showed an overall consensus regarding the need for improving sexual health education in Greenland. The participants requested more voluntary educators, to secure sustainability. The articulation of taboo topics in the Greenlandic society appeared very important. The participants suggested more awareness by promoting the project. Cultural values and language directions were important elements in the FGIs. To our knowledge, voluntary work regarding peer-to-peer education and sexual health has not been structurally evaluated in Greenland before. To achieve sustainability, the project needs educators and financial support. Further research is needed to investigate

  11. 论我国 P2 P网络贷款平台的异化%Alienation of China Peer-to-peer Lending Platforms

    Institute of Scientific and Technical Information of China (English)

    朱统

    2015-01-01

    Theories of adverse selection ,information asymmetry and transaction costs were used to analyze China Peer-to-peer lending platforms alienation phenomena in this paper ,especially for the high financing costs and risks .Based on them , it discussed the reasons why China peer-to-peer lending platforms have these alienation phenomena .Finally , with the combination of British and American Peer-to-peer lending industry experience ,some beneficial suggestions have been given to promote the healthy development of China Peer-to-peer lending platforms from the perspectives of the credit risk assessment ,credit risk con-trol ,investors appropriate selection ,financial regulation and the small-medium-sized enterprises ,individual financing channels broadening .%运用逆向选择、信息不对称、交易成本等金融理论对我国P2 P网络贷款平台异化的各种现象———突出表现为融资成本高、风险大———进行分析归纳,并对我国P2 P网络贷款平台异化的原因进行了系统的探讨和论证,最后借鉴英美等国P2 P网络贷款行业发展的成功经验,从信用风险的评估、控制,投资者的适当性选择,金融监管及中小企业、个人融资渠道的拓宽等方面提出了促使我国P2 P网络贷款平台规范、健康发展的有益建议。

  12. Hybrid Noncoherent Network Coding

    CERN Document Server

    Skachek, Vitaly; Nedic, Angelia

    2011-01-01

    We describe a novel extension of subspace codes for noncoherent networks, suitable for use when the network is viewed as a communication system that introduces both dimension and symbol errors. We show that when symbol erasures occur in a significantly large number of different basis vectors transmitted through the network and when the min-cut of the networks is much smaller then the length of the transmitted codewords, the new family of codes outperforms their subspace code counterparts. For the proposed coding scheme, termed hybrid network coding, we derive two upper bounds on the size of the codes. These bounds represent a variation of the Singleton and of the sphere-packing bound. We show that a simple concatenated scheme that represents a combination of subspace codes and Reed-Solomon codes is asymptotically optimal with respect to the Singleton bound. Finally, we describe two efficient decoding algorithms for concatenated subspace codes that in certain cases have smaller complexity than subspace decoder...

  13. 基于WebRTC的对等视频会议模型%Peer-to-Peer Video Conference Model Based on WebRTC

    Institute of Scientific and Technical Information of China (English)

    刘浩; 李千目

    2014-01-01

    Traditional peer-to-peer video conference system has very high requirements for both network and hardware condition,which causes the quality of video conference to degrade. To improve this situation, a WebRTC Based Video Conference model,WVCM,is proposed in this paper. This model can reach the same scale as traditional conference model with lower resource cost by reducing the amount of targets observed at the same time. Then,a target joining and leaving algorithm is introduced to enable quick target switch. These features make WVCM very suitable for the situation,such as mobile conference,where conference participants are more than targets to be watched simultaneously. Experiments show that WVCM can reduce traffic and scale up the conference without harming service quality.%传统对等视频会议系统对网络和硬件条件要求较高,容易导致视频会议交互质量较差。针对这个问题,本文提出一种适用于单一时刻关注目标数小于参与者总数时(如移动端会议)的对等视频会议模型( WebRTC based video conference model,WVCM)。该模型基于WebRTC媒体处理引擎,减少同时关注的目标数,使用少于传统模型的资源消耗就达到了与传统模型相当的规模,并通过目标加入和退出算法实现对会议中所关注目标的快速切换以及模型的维护。实验结果表明,WVCM能在保证会议质量的前提下有效减少网络流量并扩大会议规模。

  14. Distributed Identification of Top-l Inner Product Elements and its Application in a Peer-to-Peer Network

    Data.gov (United States)

    National Aeronautics and Space Administration — Inner product computation is an important primitive used in many techniques for feature dependency detection, distance computation, clustering and correlation...

  15. CoLab: A Collaborative Laboratory for Facilitating Code Reviews through a Peer-to-Peer Network

    Science.gov (United States)

    Kini, Shwetha

    2010-01-01

    CoLab is a collaborative tool for peer review of software programs for providing constructive feedback to first-time programmers. It targets two kinds of users: a trainer (who is the facilitator) and a trainee (whose programming skills have to be assessed and, if needed, improved). The tool provides real-time information on the reviewing ability…

  16. MOBI-DIC: MOBIle DIssemination of loCal information in Peer-to-Peer Wireless Networks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Information Technology (IT) is a key element in the successful achievement of NASA's strategic goals. Modern IT tools and techniques have the capability to redefine...

  17. The Building Bridges Project: Involving Older Adults in the Design of a Communication Technology to Support Peer-to-Peer Social Engagement

    Science.gov (United States)

    Wherton, Joseph; Prendergast, David

    There are a variety of factors that can lead to social isolation and loneliness in old age, including decline in physical and mental health, as well as change to social environment. The Building Bridges project explores how communication technology can help older adults remain socially connected. This paper will first provide an overview of a prototype communication system designed to support peer-to-peer group interaction. A description of the user-centered design process will be provided to demonstrate the importance of involving older adults at the earliest stages. The implications for designing new technology for older adults are discussed.

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

    OpenAIRE

    Wilson Rafael Ríos Ruiz

    2008-01-01

    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...

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    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.

  1. In Pursuit of Theoretical Ground in Behavior Change Support Systems: Analysis of Peer-to-Peer Communication in a Health-Related Online Community

    Science.gov (United States)

    Cobb, Nathan; Cohen, Trevor

    2016-01-01

    Background Research studies involving health-related online communities have focused on examining network structure to understand mechanisms underlying behavior change. Content analysis of the messages exchanged in these communities has been limited to the “social support” perspective. However, existing behavior change theories suggest that message content plays a prominent role reflecting several sociocognitive factors that affect an individual’s efforts to make a lifestyle change. An understanding of these factors is imperative to identify and harness the mechanisms of behavior change in the Health 2.0 era. Objective The objective of this work is two-fold: (1) to harness digital communication data to capture essential meaning of communication and factors affecting a desired behavior change, and (2) to understand the applicability of existing behavior change theories to characterize peer-to-peer communication in online platforms. Methods In this paper, we describe grounded theory–based qualitative analysis of digital communication in QuitNet, an online community promoting smoking cessation. A database of 16,492 de-identified public messages from 1456 users from March 1-April 30, 2007, was used in our study. We analyzed 795 messages using grounded theory techniques to ensure thematic saturation. This analysis enabled identification of key concepts contained in the messages exchanged by QuitNet members, allowing us to understand the sociobehavioral intricacies underlying an individual’s efforts to cease smoking in a group setting. We further ascertained the relevance of the identified themes to theoretical constructs in existing behavior change theories (eg, Health Belief Model) and theoretically linked techniques of behavior change taxonomy. Results We identified 43 different concepts, which were then grouped under 12 themes based on analysis of 795 messages. Examples of concepts include “sleepiness,” “pledge,” “patch,” “spouse,” and

  2. Peer-to-peer nursing rounds and hospital-acquired pressure ulcer prevalence in a surgical intensive care unit: a quality improvement project.

    Science.gov (United States)

    Kelleher, Alyson Dare; Moorer, Amanda; Makic, MaryBeth Flynn

    2012-01-01

    We conducted a quality improvement project in order to evaluate the effect of nurse-to-nurse bedside "rounding" as a strategy to decrease hospital-acquired pressure ulcers (HAPU) in a surgical intensive care unit. We instituted weekly peer-to-peer bedside skin rounds in a 17-bed surgical intensive care unit. Two nurses were identified as skin champions and trained by the hospital's certified WOC nurse to conduct skin rounds. The skin champion nurses conducted weekly peer-to-peer rounds that included discussions about key elements of our patients' skin status including current Braden Scale for Pressure Sore Risk score, and implementation of specific interventions related to subscale risk assessment. If a pressure ulcer was present, the current action plan was reevaluated for effectiveness. Quarterly HAPU prevalence studies were conducted from January 2008 to December 2010. Nineteen patients experienced a HAPU: 17 were located on the coccyx and 2 on the heel. Ten ulcers were classified as stage II, 3 PU were stage IV, 5 were deemed unstageable, and 1 was classified as a deep tissue injury. The frequency of preventive interventions rose during our quality improvement project. Specifically, the use of prevention surfaces increased 92%, repositioning increased 30%, nutrition interventions increased 77%, and moisture management increased 100%. Prior to focused nursing rounds, the highest HAPU prevalence rate was 27%. After implementing focused nursing rounds, HAPU rates trended down and were 0% for 3 consecutive quarters.

  3. Peer-Assisted Content Distribution with Random Linear Network Coding

    DEFF Research Database (Denmark)

    Hundebøll, Martin; Ledet-Pedersen, Jeppe; Sluyterman, Georg

    2014-01-01

    Peer-to-peer networks constitute a widely used, cost-effective and scalable technology to distribute bandwidth-intensive content. The technology forms a great platform to build distributed cloud storage without the need of a central provider. However, the majority of todays peer-to-peer systems r...

  4. 基于对等网络的医学影像服务系统通讯平台设计与应用%Design and application of peer to peer medical imaging services system communication platform

    Institute of Scientific and Technical Information of China (English)

    徐刚

    2012-01-01

    Through the establishment of peer to peer (P2P) medical imaging communication platform to study such networks application in various medical imaging services, its organizational structure design and Node Manager are described, and the establishment of linking ways of P2P nodes in different regions is elaborated. It elaborates application ways of the medical imaging P2P network communications platform through the example of the remote on-line consultation .%通过建立医学影像对等网络通讯平台,以便于研究对等网络在各医学影像服务中的应用,描述了其组织结构设计与节点管理,阐述了对等节点间在不同区域建立通讯连接的方法,通过远程在线会诊为实例,把医学影像对等网络通讯平台的使用方法进行了详细的介绍。

  5. EPSS:可扩展的P2P流媒体模拟器%EPSS:An Extensible Peer-to-Peer Streaming Simulator

    Institute of Scientific and Technical Information of China (English)

    吴吉庆; 刘锋; 彭宇行

    2011-01-01

    As peer-to-peer streaming service on the Internet becomes more and more popular, simulators are necessary for the research and improvement of the peer-to-peer streaming systems. However, the existing simulators are all hard to extend their functions, which is inconvenient for research workers to achieve their goals. Therefore, we design and implement an Extensible Peer-to-Peer Streaming simulator; EPSS, which is an event-driven, packet-level and python-based simulator. In order to make EPSS extensible, we make a clear division of modules and extensible design of interfaces. The results of our experiments show that EPSS is not only easy to extend its functions but also scalable, so it is a better choice for the research workers of P2P streaming.%随着互联网上P2P流媒体服务的流行,P2P流媒体系统模拟器也成为实现和改进实际系统必不可少的工具.但是,现有的模拟器普遍存在功能扩充困难的问题,用户若想实现自己的研究目标,往往需要花费较多的时间和精力对模拟器进行定制.基于此,我们设计和实现了一款可以灵活扩展功能的P2P流媒体模拟器:EPSS.EPSS是一款事件驱动的报文级的模拟器,基于Python实现,为了实现EPSS功能上的可扩展性,我们进行了清晰的模块划分和可扩展的接口设计.实验结果表明,EPSS不仅可以方便地进行功能扩充以支持多种研究,而且能支持很大的仿真规模,为P2P流媒体领域的研究人员提供了更好的选择.

  6. Cluster based hierarchical resource searching model in P2P network

    Institute of Scientific and Technical Information of China (English)

    Yang Ruijuan; Liu Jian; Tian Jingwen

    2007-01-01

    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.

  7. Throughput Improvement In Wireless Mesh Networks By Integrating With Optical Network

    Directory of Open Access Journals (Sweden)

    Chakrapani gadde

    2012-06-01

    Full Text Available In the last decade wireless mesh networks (WMNs have emerged as a key technology for next generation wireless networking. Because of their advantages over other wireless networks, WMNs are undergoing rapid progress and inspiring numerous applications. One such application is to provide peer-to-peer communication for all the users who are distributed over some area. Since the users are connected in awireless multi-hop passion complete ubiquity is provided. But as the number of users accessing the network is increasing there could be a chance of experiencing more interference by each user due to the communication link of every other user. So in a wireless mesh network as the load increases the throughput of network is going to be decreased due to wireless interference by other users. To sustain this problem we are going to integrate the WMN with passive optical network (PON. The resulting hybrid network (Optical-wireless network could reduce the wireless hops of each user, so that we can reduce the total wireless interference experienced by each user resulting in improved network throughput. This paper aims to study the network throughput gain in Optical-wireless network subject to peer-to-peer communications.

  8. Inference in hybrid Bayesian networks

    DEFF Research Database (Denmark)

    Lanseth, Helge; Nielsen, Thomas Dyhre; Rumí, Rafael

    2009-01-01

    Since the 1980s, Bayesian Networks (BNs) have become increasingly popular for building statistical models of complex systems. This is particularly true for boolean systems, where BNs often prove to be a more efficient modelling framework than traditional reliability-techniques (like fault trees...... decade's research on inference in hybrid Bayesian networks. The discussions are linked to an example model for estimating human reliability....

  9. Local Farmers' Organisations: A Space for Peer-to-Peer Learning? The Case of Milk Collection Cooperatives in Morocco

    Science.gov (United States)

    Faysse, Nicolas; Srairi, Mohamed Taher; Errahj, Mostafa

    2012-01-01

    Purpose: The study investigated to what extent local farmers' organisations are spaces where farmers discuss, learn and innovate. Design/methodology/approach: Two milk collection cooperatives in Morocco were studied. The study analysed the discussion networks, their impacts on farmers' knowledge and innovation, and the performance of collective…

  10. Unified Hybrid Network Theoretical Model Trilogy

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The first of the unified hybrid network theoretical model trilogy (UHNTF) is the harmonious unification hybrid preferential model (HUHPM), seen in the inner loop of Fig. 1, the unified hybrid ratio is defined.

  11. Exploring proximity based peer clustering in BitTorrent-like Peer-to-Peer file sharing systems

    Institute of Scientific and Technical Information of China (English)

    Yu Jiadi; Li Minglu

    2008-01-01

    A hierarchical clustered BitTorrent (CBT) system is proposed to improve the file sharing performance of the BitTorrent system, in which peers are grouped into clusters in a large-scale BitTorrent-like underlying overlay network in such a way that clusters are evenly distributed and that the peers within the cluster are relatively close to each other. A fluid model is developed to compare the performance of the proposed CBT system with the BitTorrent system, and the result shows that the CBT system can effectively improve the performance of the system. Simulation results also demonstrate that the CBT system improves the system scalability and efficiency while retaining the robustness and incentives of the original BitTorrent paradigm.

  12. Let’s Chat - A fresh take on the invaluable role of peer-to-peer conversation in student engagement, participation and inclusion

    Directory of Open Access Journals (Sweden)

    Rosalind McFarlane

    2017-07-01

    Full Text Available This session reports on Monash University’s recently developed Let’s Chat program, delivered at three campuses as a modularised, peer learning opportunity for students from first year to PhD. Involving 3,591 student participants and facilitators in 2015 and 2016, the program responds directly to student feedback and recommendations. Let’s Chat maximises opportunities for peer-to-peer interaction with the aim of increasing participants’ confidence and competence in spoken English and intercultural communication. Informed by current trends in student-centred and peer-assisted learning theory, TESOL and intercultural communication, Let’s Chat is quickly establishing itself as an effective approach to supporting student participation, engagement and sense of belonging in diverse teaching and learning contexts and communities. The session presents a snapshot of the genesis of the program; an evaluation of its implementation; and a summary of emerging outcomes. The session also engages participants in a conversation about how this model might be replicated in other settings.

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

    Directory of Open Access Journals (Sweden)

    Wilson Rafael Ríos Ruiz

    2008-11-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Wilson Rafael Ríos Ruiz

    2008-11-01

    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.

  15. Hybrid-Source Impedance Networks

    DEFF Research Database (Denmark)

    Li, Ding; Gao, Feng; Loh, Poh Chiang;

    2010-01-01

    the cascaded networks would have a higher output voltage gain and other unique advantages that currently have not been investigated yet. It is anticipated that these advantages would help the formed inverters find applications in photovoltaic and other renewable systems, where a high voltage gain is usually......Hybrid-source impedance networks have attracted attention among researchers because of their flexibility in performing buck-boost energy conversion. To date, three distinct types of impedance networks can be summarized for implementing voltage-type inverters with another three types summarized...

  16. Effectiveness of web-based self-disclosure peer-to-peer support for weight loss: randomized controlled trial.

    Science.gov (United States)

    Imanaka, Mie; Ando, Masahiko; Kitamura, Tetsuhisa; Kawamura, Takashi

    2013-07-09

    from the WSHS group and 8 from the EHS group dropped out during the study period, and the remaining 87 in the WSHS group and 88 in the EHS group were followed up completely. Weight loss was significantly greater in the WSHS group than in the EHS group (-1.6 kg vs -0.7 kg; adjusted P=.04). However, there were few differences in waist circumference between the 2 groups. (-3.3 cm vs -3.0 cm; adjusted P=.71). Our newly developed WSHS system using forced self-disclosure had better short-term weight loss results. Further study in a longer-term trial is necessary to determine what effects this type of intervention might have on long-term cardiovascular disease. University Hospital Medical Information Network Clinical Trial Registration (UMIN-CTR): UMIN000009147; https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&type=summary&recptno=R000010719&language=E (Archived by WebCite at http://www.webcitation.org/6HTCkhb1p).

  17. 基于1x EV-DO网络的移动互联网业务端到端分析优化方法研究%Research on Peer to Peer Analysis and Optimization Method of Mobile Internet Services Based on 1x EV-DO

    Institute of Scientific and Technical Information of China (English)

    罗文红; 王兵; 钱少波

    2013-01-01

    With the increasing users’demands for 3G services, telecommunication operators need to take advantage of all the information of various services to promote the service management, the quality of service and user perception. A peer to peer analysis and optimization method is presented. First, the definition and the steps of the method are introduced. Second, the HTTP service with higher rate of service penetration is taken as an example, by fully analyzing the factors which affects the quality of service, a service quality evaluating system is builded. At the end, by optimizing core network, wireless network, service platform and user terminal, the function of this method in improving bearing performance, application services and user perception of the peer to peer network is introduced.%随着用户对3G业务的要求越来越高,运营商需充分利用各种业务运行信息,推进业务管理的精细化,提高业务质量和用户感知。提出了端到端分析优化方法,介绍了该方法的定义和步骤,并以业务渗透率较高的网页HTTP类业务为例,通过全程分析影响业务质量的因素,建立业务质量评估体系,从核心网、无线网、业务平台、终端等方面进行优化,说明了该方法对提升端到端的网络承载性能、应用业务性能和用户感知的作用。

  18. Know the Network, Knit the Network: Applying SNA to N2C2 Maturity Model Experiments

    Science.gov (United States)

    2010-06-01

    Management Proceedings. Clark, Louise. Network Mapping As a Diagnostic Tool. Centro Internacional de Agricultura Tropical (CIAT). Bolivia. March 2006...Microscopic Peer-to-Peer Communication Patterns. Americas Conference on Information Systems. Gloor, Peter, Maria Paasivaara, Detlef Schoder and Paul

  19. What Do You Say Before You Relapse? How Language Use in a Peer-to-peer Online Discussion Forum Predicts Risky Drinking among Those in Recovery.

    Science.gov (United States)

    Kornfield, Rachel; Toma, Catalina L; Shah, Dhavan V; Moon, Tae Joon; Gustafson, David H

    2017-08-09

    Increasingly, individuals with alcohol use disorder (AUD) seek and provide support for relapse prevention in text-based online environments such as discussion forums. This paper investigates whether language use within a peer-to-peer discussion forum can predict future relapse among individuals treated for AUD. A total of 104 AUD sufferers who had completed residential treatment participated in a mobile phone-based relapse-prevention program, where they communicated via an online forum over the course of a year. We extracted patterns of language use on the forum within the first four months on study using Linguistic Inquiry and Word Count (LIWC), a dictionary-based text analysis program. Participants reported their incidence of risky drinking via a survey at 4, 8, and 12 months. A logistic regression model was built to predict the likelihood that individuals would engage in risky drinking within a year based on their language use, while controlling for baseline characteristics and rates of utilizing the mobile system. Results show that all baseline characteristics and system use factors explained just 13% of the variance in relapse, whereas a small number of linguistic cues, including swearing and cognitive mechanism words, accounted for an additional 32% of the total 45% of variance in relapse explained by the model. Effective models for predicting relapse are needed. Messages exchanged on AUD forums could provide an unobtrusive and cost-effective window into the future health outcomes of AUD sufferers, and their psychological underpinnings. As online communication expands, models that leverage user-submitted text toward predicting relapse will be increasingly scalable and actionable.

  20. Genomic networks of hybrid sterility.

    Directory of Open Access Journals (Sweden)

    Leslie M Turner

    2014-02-01

    Full Text Available Hybrid dysfunction, a common feature of reproductive barriers between species, is often caused by negative epistasis between loci ("Dobzhansky-Muller incompatibilities". The nature and complexity of hybrid incompatibilities remain poorly understood because identifying interacting loci that affect complex phenotypes is difficult. With subspecies in the early stages of speciation, an array of genetic tools, and detailed knowledge of reproductive biology, house mice (Mus musculus provide a model system for dissecting hybrid incompatibilities. Male hybrids between M. musculus subspecies often show reduced fertility. Previous studies identified loci and several X chromosome-autosome interactions that contribute to sterility. To characterize the genetic basis of hybrid sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL. Many trans eQTL cluster into eleven 'hotspots,' seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL-but not cis eQTL-were substantially lower when mapping was restricted to a 'fertile' subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility. The integrated mapping approach we employed is

  1. Genomic networks of hybrid sterility.

    Science.gov (United States)

    Turner, Leslie M; White, Michael A; Tautz, Diethard; Payseur, Bret A

    2014-02-01

    Hybrid dysfunction, a common feature of reproductive barriers between species, is often caused by negative epistasis between loci ("Dobzhansky-Muller incompatibilities"). The nature and complexity of hybrid incompatibilities remain poorly understood because identifying interacting loci that affect complex phenotypes is difficult. With subspecies in the early stages of speciation, an array of genetic tools, and detailed knowledge of reproductive biology, house mice (Mus musculus) provide a model system for dissecting hybrid incompatibilities. Male hybrids between M. musculus subspecies often show reduced fertility. Previous studies identified loci and several X chromosome-autosome interactions that contribute to sterility. To characterize the genetic basis of hybrid sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven 'hotspots,' seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL-but not cis eQTL-were substantially lower when mapping was restricted to a 'fertile' subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility. The integrated mapping approach we employed is applicable in a broad

  2. 因特网上基于对等网络的服务网格平台构建%Construction for Peer-to-Peer Based Service Grid Platform over the Internet

    Institute of Scientific and Technical Information of China (English)

    周明; 王太勇

    2011-01-01

    提出与描述了适合大规模因特网环境的对等网络服务网格平台PSGP(P2P-based Service Grid Platform)的设计、实现与性能评测.PSGP平台结合了对等网络技术、网格的Web Serrices技术、面向服务的框架技术,使得PSGP平台具有非集中性、可扩展性、互操作性与鲁棒性好的优点.使用对等网络的JXTA协议完成对等实体的组织、资源发现、服务调用的功能.通过设置对等实体的衔级、安全的认证机制等高级技术保证了平台的安全性与可信任机制.并行应用的案例测试表明,PSGP在对等实体的通信轮回时间、应用的吞吐量上,具有较好的性能,可以作为实现大规模的分布式模拟的可行方案.%The design, implementation and performance evaluation of a P2P-based Service Grid Platform called PSGP over the Internet was presented and described in this paper. Using peer-to-peer networks technology, Grid web services technology and services oriented framework, PSGP can get the good characters of decentralization, scalability, interoperability and robustness. A general-purpose P2P library, JXTA was also used in PSGP over which peers can communicate with each other, and thus peer organization, peer resource discovery and services method invocation can benefit a lot from JXTA. The results obtained from example applications and performance analysis show that time of turnaround and throughput of PSGP was good. PSGP is a feasible approach for large scale parallel and distributed computation.

  3. A Design of Peer-to-Peer Service Network Topology%一种P2P Service Overlay网络拓扑设计

    Institute of Scientific and Technical Information of China (English)

    高晓燕; 余镇危; 武颖; 史银龙

    2008-01-01

    在经典P2P网络结构中,所有节点都处于对等地位,没有考虑节点的不同处理能力,不能够保证服务的质量.本文在P2P网络中,引入服务质量属性,构造基于服务质量的Overlay子网,用来提高P2P整体网络性能,并保证单个节点的服务质量.最后给出一种在P2P网络中构造Overlay子网拓扑结构的方法,并给出了相应的实验结果.

  4. An Ant Intelligence Routing Scheme for Peer-to-Peer Networks%基于蚁群算法的P2P路由策略

    Institute of Scientific and Technical Information of China (English)

    向泰; 吴高凯; 张丽英

    2011-01-01

    目前P2P网络面临的两大难题:消息泛洪和free-rider,为了更好地解决这两个问题,提出了一种基于蚁群策略的路由策略,在每个节点建立了路由信息素表和请求应答数表,对等点可以根据信息素的值来选择成功率高的路径,只发送消息给部分节点,有效控制了消息的泛洪和拥塞的产生,通过奖励机制,有效减少了free-rider.

  5. Design of Peer-to-Peer Network Reputation Evaluation System%Peer-to-Peer网络信誉评价体系的设计

    Institute of Scientific and Technical Information of China (English)

    门涛; 文军

    2005-01-01

    分析了P2P网络共享文件的可靠性问题,以及各种解决方法的优缺点,提出了一种基于文件内容的信誉评价体系模型,该体系模型通过收集各个节点的评价信息,来保证共享文件的真实性和可靠性.

  6. 一种新型P2P网络信任模型研究%Research on a Novel Trust Peer-to-Peer Network Model

    Institute of Scientific and Technical Information of China (English)

    王帅

    2012-01-01

    This paper proposes a new trust model-Hierarchical and Distributed Region-based Trust Model-HDRTM. This model is based on the historical interactive information and credibility recommended, and uses the methods of measurement and the combination rule to assess the trust of the peers.Meanwhile,thereliability and authenticity are enhanced via introducing the regulatory punishment factors and the weighting factors of the synthesis rule.Systems simulation indicates that HDRTM is able to resist malicious peers effectively and has goodsecurity and trust.%本文提出了一种新的P2P网络信任模型——层次化分布域信任模型HDRTM。该模型基于历史交互信息和信誉推荐,采用量化方法和合成规则方法得到的信任度对P2P网络中的节点信任进行评估,同时引入了惩罚调节因子、合成规则权重因子等加强了信任度的可靠性与真实性。对HDRTM的仿真证明能够有效抵制恶意节点,具有较好的安全性与信任性。

  7. Network-aware SuperPeers-Peers Geometric Overlay Network

    NARCIS (Netherlands)

    Lua, E.K.; Zhou, X.

    2007-01-01

    Peer-to-Peer (P2P) overlay networks can be utilized to deploy massive Internet overlay services such as multicast, content distribution, file sharing, etc. efficiently without any underlying network support. The crucial step to meet this objective is to design network-aware overlay network

  8. Network-aware SuperPeers-Peers Geometric Overlay Network

    NARCIS (Netherlands)

    Lua, E.K.; Zhou, X.

    2007-01-01

    Peer-to-Peer (P2P) overlay networks can be utilized to deploy massive Internet overlay services such as multicast, content distribution, file sharing, etc. efficiently without any underlying network support. The crucial step to meet this objective is to design network-aware overlay network topologie

  9. Network-aware SuperPeers-Peers Geometric Overlay Network

    NARCIS (Netherlands)

    Lua, E.K.; Zhou, X.

    2007-01-01

    Peer-to-Peer (P2P) overlay networks can be utilized to deploy massive Internet overlay services such as multicast, content distribution, file sharing, etc. efficiently without any underlying network support. The crucial step to meet this objective is to design network-aware overlay network topologie

  10. Hybrid percolation transition in complex networks

    Science.gov (United States)

    Kahng, Byungnam

    Percolation has been one of the most applied statistical models. Percolation transition is one of the most robust continuous transitions known thus far. However, recent extensive researches reveal that it exhibits diverse types of phase transitions such as discontinuous and hybrid phase transitions. Here hybrid phase transition means the phase transition exhibiting natures of both continuous and discontinuous phase transitions simultaneously. Examples include k-core percolation, cascading failures in interdependent networks, synchronization, etc. Thus far, it is not manifest if the critical behavior of hybrid percolation transitions conforms to the conventional scaling laws of second-order phase transition. Here, we investigate the critical behaviors of hybrid percolation transitions in the cascading failure model in inter-dependent networks and the restricted Erdos-Renyi model. We find that the critical behaviors of the hybrid percolation transitions contain some features that cannot be described by the conventional theory of second-order percolation transitions.

  11. Expediting P2P Video Delivery through a Hybrid Push-Pull Protocol

    Directory of Open Access Journals (Sweden)

    LEE, C.

    2015-11-01

    Full Text Available Despite the recent phenomenal success of peer-to-peer video streaming services, their stumbling performance for high-quality videos remains a major obstacle to wider acceptance. This is because high-resolution videos instantly delivered over the Internet are increasingly becoming the norm. This paper presents a novel solution to keep up with ever more challenging QoE expectations. Our proposal of a hybrid push-pull protocol consists of two key components, namely, a new push strategy and an elastic window scheme. The former empowers the hybrid protocol to make an informed push-pull decision based on chunk status and network condition, whereas the latter ensures balance between the two conflicting goals of chunk dissemination and playback deadline. The efficacy of the proposed protocol is validated through a performance study that demonstrates substantial gains compared to existing approaches.

  12. Hybrid neural network models of transducers

    Science.gov (United States)

    Xie, Shilin; Zhang, Xinong; Chen, Shenglai; Zhu, Changchun

    2011-10-01

    A hybrid neural network (NN) approach is proposed and applied to modeling of transducers in the paper. The modeling procedures are also presented in detail. First, the simulated studies on the modeling of single input-single output and multi input-multi output transducers are conducted respectively by use of the developed hybrid NN scheme. Secondly, the hybrid NN modeling approach is utilized to characterize a six-axis force sensor prototype based on the measured data. The results show that the hybrid NN approach can significantly improve modeling precision in comparison with the conventional modeling method. In addition, the method is superior to NN black-box modeling because the former possesses smaller network scale, higher convergence speed, higher model precision and better generalization performance.

  13. Hybrid Dynamic Network Data Envelopment Analysis

    Directory of Open Access Journals (Sweden)

    Ling Li

    2015-01-01

    Full Text Available Conventional DEA models make no hypothesis concerning the internal operations in a static situation. To open the “black box” and work with dynamic assessment issues synchronously, we put forward a hybrid model for evaluating the relative efficiencies of a set of DMUs over an observed time period with a composite of network DEA and dynamic DEA. We vertically deal with intermediate products between divisions with assignable inputs in the network structure and, horizontally, we extend network structure by means of a dynamic pattern with unrelated activities between two succeeding periods. The hybrid dynamic network DEA model proposed in this paper enables us to (i pry into the internal operations of DEA by another network structure, (ii obtain dynamic change of period efficiency, and (iii gain the overall dynamic efficiency of DMUs over the entire observed periods. We finally illustrate the calculation procedure of the proposed approach by a numerical example.

  14. Evaluación de las arquitecturas de Participación Activa del Proveedor de Red en Redes "Peer-to-Peer": Aplicación a escenarios de Televisión IP

    OpenAIRE

    Sánchez Tena, Carlos

    2010-01-01

    El presente Proyecto Fin de Carrera consiste en el estudio de nuevas tecnologías aparecidas en los últimos años que intentan mejorar el tráfico generado por la compartición de archivos a través de las redes de peer-to-peer. Una de las tecnologías que se estudiarán será la tecnología de Participación Activa del Proveedor de Red en P2P (P4P) que mediante información dada por los proveedores de infraestructura de red selecciona los pares idóneos. Se estudiará esta tecnología detallando su fun...

  15. H-P2PSIP: Interconnection of P2PSIP domains for Global Multimedia Services based on a Hierarchical DHT Overlay Network

    OpenAIRE

    Martínez-Yelmo, Isaías; Bikfalvi, Alex; Cuevas, Rubén; Guerrero, Carmen; García-Reinoso, Jaime

    2009-01-01

    The IETF P2PSIP WG is currently standardising a protocol for distributed mul- timedia services combining the media session functionality of SIP and the decentralised distribution and localisation of resources in peer-to-peer networks. The current P2PSIP scenarios only consider the infrastructure for the connectivity inside a single domain. This paper proposes an extension of the current work to a hierarchical multi-domain scenario: a two level hierarchical peer-to-peer overlay architecture...

  16. Influence of Deterministic Attachments for Large Unifying Hybrid Network Model

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Large unifying hybrid network model (LUHPM) introduced the deterministic mixing ratio fd on the basis of the harmonious unification hybrid preferential model, to describe the influence of deterministic attachment to the network topology characteristics,

  17. Hybrid simulation models of production networks

    CERN Document Server

    Kouikoglou, Vassilis S

    2001-01-01

    This book is concerned with a most important area of industrial production, that of analysis and optimization of production lines and networks using discrete-event models and simulation. The book introduces a novel approach that combines analytic models and discrete-event simulation. Unlike conventional piece-by-piece simulation, this method observes a reduced number of events between which the evolution of the system is tracked analytically. Using this hybrid approach, several models are developed for the analysis of production lines and networks. The hybrid approach combines speed and accuracy for exceptional analysis of most practical situations. A number of optimization problems, involving buffer design, workforce planning, and production control, are solved through the use of hybrid models.

  18. Filtering in hybrid dynamic Bayesian networks

    DEFF Research Database (Denmark)

    Andersen, Morten Nonboe; Andersen, Rasmus Ørum; Wheeler, Kevin

    2004-01-01

    We demonstrate experimentally that inference in a complex hybrid Dynamic Bayesian Network (DBN) is possible using the 2-Time Slice DBN (2T-DBN) from (Koller & Lerner, 2000) to model fault detection in a watertank system. In (Koller & Lerner, 2000) a generic Particle Filter (PF) is used for infere...

  19. Filtering in hybrid dynamic Bayesian networks (left)

    DEFF Research Database (Denmark)

    Andersen, Morten Nonboe; Andersen, Rasmus Ørum; Wheeler, Kevin

    We demonstrate experimentally that inference in a complex hybrid Dynamic Bayesian Network (DBN) is possible using the 2-Time Slice DBN (2T-DBN) from (Koller & Lerner, 2000) to model fault detection in a watertank system. In (Koller & Lerner, 2000) a generic Particle Filter (PF) is used for infere...

  20. Filtering in hybrid dynamic Bayesian networks (center)

    DEFF Research Database (Denmark)

    Andersen, Morten Nonboe; Andersen, Rasmus Ørum; Wheeler, Kevin

    We demonstrate experimentally that inference in a complex hybrid Dynamic Bayesian Network (DBN) is possible using the 2-Time Slice DBN (2T-DBN) from (Koller & Lerner, 2000) to model fault detection in a watertank system. In (Koller & Lerner, 2000) a generic Particle Filter (PF) is used for infere...

  1. VB based on TCP/IP Protocol Peer-to-peer File Transfer%VB中基于TCP/IP协议的点对点文件传输

    Institute of Scientific and Technical Information of China (English)

    高永强; 李翠莲

    2012-01-01

    随着网络的普及,网络编程显得尤其重要。文章使用Winsock控件实现两台计算机间的文件传输,描述了Winsock控件的使用方法及有关文件传输的算法。%With the popularity of the network,network programming is particularly important.In this paper,using the Winsock control to achieve the file transfer between two computers,describes the Winsock control the use of methods and relevant file transfer algorithm.

  2. Hybrid architecture for building secure sensor networks

    Science.gov (United States)

    Owens, Ken R., Jr.; Watkins, Steve E.

    2012-04-01

    Sensor networks have various communication and security architectural concerns. Three approaches are defined to address these concerns for sensor networks. The first area is the utilization of new computing architectures that leverage embedded virtualization software on the sensor. Deploying a small, embedded virtualization operating system on the sensor nodes that is designed to communicate to low-cost cloud computing infrastructure in the network is the foundation to delivering low-cost, secure sensor networks. The second area focuses on securing the sensor. Sensor security components include developing an identification scheme, and leveraging authentication algorithms and protocols that address security assurance within the physical, communication network, and application layers. This function will primarily be accomplished through encrypting the communication channel and integrating sensor network firewall and intrusion detection/prevention components to the sensor network architecture. Hence, sensor networks will be able to maintain high levels of security. The third area addresses the real-time and high priority nature of the data that sensor networks collect. This function requires that a quality-of-service (QoS) definition and algorithm be developed for delivering the right data at the right time. A hybrid architecture is proposed that combines software and hardware features to handle network traffic with diverse QoS requirements.

  3. Multiuser Cooperation with Hybrid Network Coding in Wireless Networks

    Directory of Open Access Journals (Sweden)

    G. Wang

    2014-04-01

    Full Text Available In this paper a hybrid Network Coding Cooperation (hybrid-NCC system is proposed to achieve both reliable transmission and high throughput in wireless networks. To balance the transmission reliability with throughput, the users are divided into cooperative sub-networks based on the geographical information, and the cooperation is implemented in each sub-network. After receiving signals from the cooperative partners, each user encodes them by exploiting hybrid network coding and then forwards the recoded symbols via the Link-Adaptive Regenerative (LAR relaying. First, the Diversity-Multiplexing Tradeoff (DMT is analyzed to demonstrate that the proposed system is bandwidth-efficient. Second, the Symbol Error Probability (SEP is also derived, which shows that the proposed system achieves a higher reliability as compared to the traditional Complex Field Network Coding Cooperation (CFNCC. Moreover, because dedicated relays are not required, our proposed system can both reduce the costs and enhance the flexibility of the implementation. Finally, the analytical results are supported and validated by numerical simulations.

  4. Hybrid Mobile Communication Networks for Planetary Exploration

    Science.gov (United States)

    Alena, Richard; Lee, Charles; Walker, Edward; Osenfort, John; Stone, Thom

    2007-01-01

    A paper discusses the continuing work of the Mobile Exploration System Project, which has been performing studies toward the design of hybrid communication networks for future exploratory missions to remote planets. A typical network could include stationary radio transceivers on a remote planet, mobile radio transceivers carried by humans and robots on the planet, terrestrial units connected via the Internet to an interplanetary communication system, and radio relay transceivers aboard spacecraft in orbit about the planet. Prior studies have included tests on prototypes of these networks deployed in Arctic and desert regions chosen to approximate environmental conditions on Mars. Starting from the findings of the prior studies, the paper discusses methods of analysis, design, and testing of the hybrid communication networks. It identifies key radio-frequency (RF) and network engineering issues. Notable among these issues is the study of wireless LAN throughput loss due to repeater use, RF signal strength, and network latency variations. Another major issue is that of using RF-link analysis to ensure adequate link margin in the face of statistical variations in signal strengths.

  5. Semantics for Hybrid Networks Using the Network Description Language

    NARCIS (Netherlands)

    Ham, J.J. van der; Grosso, P.; Dijkstra, F.; Laat, C. de

    2006-01-01

    Hybrid networks offer end users a mix of traditional connections and new optical services in the form of dedicated lightpaths. These must be requested in advance and are currently configured on demand by the operators. Because lightpaths are circuit switched, the user must be aware of the topology a

  6. A Unified Peer-to-Peer Database Framework for XQueries over Dynamic Distributed Content and its Application for Scalable Service Discovery

    CERN Document Server

    Hoschek, Wolfgang

    In a large distributed system spanning administrative domains such as a Grid, it is desirable to maintain and query dynamic and timely information about active participants such as services, resources and user communities. The web services vision promises that programs are made more flexible and powerful by querying Internet databases (registries) at runtime in order to discover information and network attached third-party building blocks. Services can advertise themselves and related metadata via such databases, enabling the assembly of distributed higher-level components. In support of this vision, this thesis shows how to support expressive general-purpose queries over a view that integrates autonomous dynamic database nodes from a wide range of distributed system topologies. We motivate and justify the assertion that realistic ubiquitous service and resource discovery requires a rich general-purpose query language such as XQuery or SQL. Next, we introduce the Web Service Discovery Architecture (WSDA), wh...

  7. Analysis of Network Parameters Influencing Performance of Hybrid Multimedia Networks

    Directory of Open Access Journals (Sweden)

    Dominik Kovac

    2013-10-01

    Full Text Available Multimedia networks is an emerging subject that currently attracts the attention of research and industrial communities. This environment provides new entertainment services and business opportunities merged with all well-known network services like VoIP calls or file transfers. Such a heterogeneous system has to be able satisfy all network and end-user requirements which are increasing constantly. Therefore the simulation tools enabling deep analysis in order to find the key performance indicators and factors which influence the overall quality for specific network service the most are highly needed. This paper provides a study on the network parameters like communication technology, routing protocol, QoS mechanism, etc. and their effect on the performance of hybrid multimedia network. The analysis was performed in OPNET Modeler environment and the most interesting results are discussed at the end of this paper

  8. Detection and prevention of Peer-to-Peer botnet%基于流量的P2P僵尸网络检测

    Institute of Scientific and Technical Information of China (English)

    李建

    2016-01-01

    The rapid development of the Internet makes it the object of attack. Because of their powerful and highly destructive attack, botnet attacks were listed as one of the most important network security threats. In order to explore the detection of P2P botnet, a detection method based on P2P technology is proposed, which through filtering suspicious traffic and DNS traffic detection etc., determines whether botnet attacks is suffered, and the defense measures to avoid botnet infection are put forward.%网络的快速发展使其成为被攻击的对象。分布式结构僵尸网络攻击以其强大的攻击性和高破坏性被列为重要的网络安全威胁之一。为探索分布式结构僵尸网络的检测方法,文章从结构、感染过程等方面分析,提出基于流量的检测方法,通过过滤可疑流量、DNS流量检测等,判定是否受到僵尸网络攻击,并提出避免感染僵尸网络的防御措施。

  9. Hybrid Optical Switching for Data Center Networks

    Directory of Open Access Journals (Sweden)

    Matteo Fiorani

    2014-01-01

    Full Text Available Current data centers networks rely on electronic switching and point-to-point interconnects. When considering future data center requirements, these solutions will raise issues in terms of flexibility, scalability, performance, and energy consumption. For this reason several optical switched interconnects, which make use of optical switches and wavelength division multiplexing (WDM, have been recently proposed. However, the solutions proposed so far suffer from low flexibility and are not able to provide service differentiation. In this paper we introduce a novel data center network based on hybrid optical switching (HOS. HOS combines optical circuit, burst, and packet switching on the same network. In this way different data center applications can be mapped to the optical transport mechanism that best suits their traffic characteristics. Furthermore, the proposed HOS network achieves high transmission efficiency and reduced energy consumption by using two parallel optical switches. We consider the architectures of both a traditional data center network and the proposed HOS network and present a combined analytical and simulation approach for their performance and energy consumption evaluation. We demonstrate that the proposed HOS data center network achieves high performance and flexibility while considerably reducing the energy consumption of current solutions.

  10. Routing of multimedia connections in hybrid networks

    Science.gov (United States)

    Koegel, John F.; Syta, Andrzej

    1993-02-01

    The prevailing vision for next generation multimedia communication systems is a digital one. However, we anticipate a transitional period in which hybrid networks involving both analog and digital technology will coexist. These analog facilities will include crossbar audio-video switches, CATV distribution systems, and dedicated lines. For some scale of use, these facilities may offer economies for connectivity to conventional analog video equipment. We are interested in connection routing that will be needed in such hybrid networks for services including video conferencing and broadcast results. The routing problem in such topologies resembles but is not identical to that found in telephone systems because of the presence of broadcast connections. We discuss representative topologies, review related work, and describe algorithms and simulation results. In addition we describe a hybrid system that we have implemented in our research lab which involves several A/V switches, CATV channels, digital video on a LAN, and a point-to-point link to an offsite conference area.

  11. Improving Peer-to-Peer Video Systems

    NARCIS (Netherlands)

    Petrocco, R.P.

    2016-01-01

    Video Streaming is nowadays the Internet’s biggest source of consumer traffic. Traditional content providers rely on centralised client-server model for distributing their video streaming content. The current generation is moving from being passive viewers, or content consumers, to active content pr

  12. Improving Peer-to-Peer Video Systems

    NARCIS (Netherlands)

    Petrocco, R.P.

    2016-01-01

    Video Streaming is nowadays the Internet’s biggest source of consumer traffic. Traditional content providers rely on centralised client-server model for distributing their video streaming content. The current generation is moving from being passive viewers, or content consumers, to active content pr

  13. Improving Peer-to-Peer Video Systems

    NARCIS (Netherlands)

    Petrocco, R.P.

    2016-01-01

    Video Streaming is nowadays the Internet’s biggest source of consumer traffic. Traditional content providers rely on centralised client-server model for distributing their video streaming content. The current generation is moving from being passive viewers, or content consumers, to active content

  14. Dynamic peer-to-peer competition

    Science.gov (United States)

    Caram, L. F.; Caiafa, C. F.; Proto, A. N.; Ausloos, M.

    2010-07-01

    The dynamic behavior of a multiagent system in which the agent size si is variable it is studied along a Lotka-Volterra approach. The agent size has hereby the meaning of the fraction of a given market that an agent is able to capture (market share). A Lotka-Volterra system of equations for prey-predator problems is considered, the competition factor being related to the difference in size between the agents in a one-on-one competition. This mechanism introduces a natural self-organized dynamic competition among agents. In the competition factor, a parameter σ is introduced for scaling the intensity of agent size similarity, which varies in each iteration cycle. The fixed points of this system are analytically found and their stability analyzed for small systems (with n=5 agents). We have found that different scenarios are possible, from chaotic to non-chaotic motion with cluster formation as function of the σ parameter and depending on the initial conditions imposed to the system. The present contribution aim is to show how a realistic though minimalist nonlinear dynamics model can be used to describe the market competition (companies, brokers, decision makers) among other opinion maker communities.

  15. Peer-to-peer information retrieval

    NARCIS (Netherlands)

    Tigelaar, Almer S.

    2012-01-01

    The Internet has become an integral part of our daily lives. However,the essential task of finding information is dominated by a handful of large centralised search engines. In this thesis we study an alternative to this approach. Instead of using large data centres, we propose using the machines th

  16. Dynamic Peer-to-Peer Competition

    CERN Document Server

    Caram, L F; Proto, A N; Ausloos, M

    2010-01-01

    The dynamic behavior of a multiagent system in which the agent size $s_{i}$ is variable it is studied along a Lotka-Volterra approach. The agent size has hereby for meaning the fraction of a given market that an agent is able to capture (market share). A Lotka-Volterra system of equations for prey-predator problems is considered, the competition factor being related to the difference in size between the agents in a one-on-one competition. This mechanism introduces a natural self-organized dynamic competition among agents. In the competition factor, a parameter $\\sigma$ is introduced for scaling the intensity of agent size similarity, which varies in each iteration cycle. The fixed points of this system are analytically found and their stability analyzed for small systems (with $n=5$ agents). We have found that different scenarios are possible, from chaotic to non-chaotic motion with cluster formation as function of the $\\sigma$ parameter and depending on the initial conditions imposed to the system. The prese...

  17. Hybrid synchronization of two independent chaotic systems on complex network

    Indian Academy of Sciences (India)

    NIAN FUZHONG; LIU WEILONG

    2016-06-01

    The real network nodes are always interfered by other messages. So, how to realize the hybrid synchronization of two independent chaotic systems based on the complex network is very important. To solve this problem, two other problems should be considered. One is how the same network node of the complex network was affected by different information sources. Another is how to achieve hybrid synchronization on the network. In this paper, the theoretical analysis andnumerical simulation on various complex networks are implemented. The results indicate that the hybrid synchronization of two independent chaotic systems is feasible.

  18. Time Series Prediction based on Hybrid Neural Networks

    Directory of Open Access Journals (Sweden)

    S. A. Yarushev

    2016-01-01

    Full Text Available In this paper, we suggest to use hybrid approach to time series forecasting problem. In first part of paper, we create a literature review of time series forecasting methods based on hybrid neural networks and neuro-fuzzy approaches. Hybrid neural networks especially effective for specific types of applications such as forecasting or classification problem, in contrast to traditional monolithic neural networks. These classes of problems include problems with different characteristics in different modules. The main part of paper create a detailed overview of hybrid networks benefits, its architectures and performance under traditional neural networks. Hybrid neural networks models for time series forecasting are discussed in the paper. Experiments with modular neural networks are given.

  19. 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

    Institute of Scientific and Technical Information of China (English)

    帅青红

    2014-01-01

    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。

  20. Inteligência estratégica antecipativa coletiva e crowdfunding: aplicação do método L.E.SCAnning em empresa social de economia peer-to-peer (P2P

    Directory of Open Access Journals (Sweden)

    Mery Blanck

    2014-03-01

    Full Text Available Neste artigo, apresentam-se os resultados de pesquisa qualitativa em que se objetivou investigar a aplicabilidade do método L.E.SCAnning em empresas sociais de economia peer-to-peer (P2P. A motivação partiu da ideia de a autossustentabilidade ser, a longo prazo, um dos maiores desafios das organizações, especialmente aquelas lastreadas na economia social, dentre elas, as empresas P2P. No entanto, empresas sociais são potencialmente negócios dinâmicos e progressistas com os quais o mercado empresarial poderia aprender, uma vez que experimentam e inovam. Partindo exatamente desse espírito inovador, muitas empresas sociais voltaram-se para o modelo crowdfunding de economia P2P, que se configura como tendência emergente de organização colaborativa de recursos na Web. Sob esse prisma, um dos novos desenvolvimentos em gestão que se aplicam à atividade de organizações com enfoque sistêmico é a prática da Inteligência Estratégica Antecipativa Coletiva (IEAc. Nesse sentido, no estudo de caso investigou-se a empresa social francesa Babyloan para compreender de que maneira a organização busca, monitora e utiliza a informação captada do meio externo para sua atuação, prototipando, com base nesse diagnóstico, a aplicação de um ciclo do método L.E.SCAnning. Os resultados deste estudo sugerem que o entendimento pragmático do cenário externo, por meio da IEAc, favorece decisões que trazem uma marca de empreendedorismo e inovação, e tem no universo da economia social P2P, ambiente fortemente baseado em percepção, um impacto potencial significativo.

  1. Content Protection for Peer-to-Peer Streaming Media Based on Digital Watermark%基于数字水印的点对点流媒体内容保护

    Institute of Scientific and Technical Information of China (English)

    缪一心; 杨明

    2011-01-01

    点对点(P2P)流媒体系统面临污染及篡改攻击、版权保护等安全问题,但P2P流媒体视频本身的特点使信息摘要、数字签名等常见的安全技术并不适用.为此,提出一种既符合P2P流媒体视频特性,又基本满足防污染、防篡改以及保护版权需求的数字水印技术,并以MPEG-2编码为例给出算法及实现过程.通过实验验证,该方法在安全、高效、完整、不可见等方面均达到设计要求.%The Peer-to-Peer(P2P) streaming video faces serious security problems such as pollution, tampering attacks and copyright protection,but due to the characteristics of the P2P streaming system, the usual security technologies, such as message digest and digital signature, are not fit for it. So, a new digital watermark is designed, which can satisfy the need of anti-pollution attack, anti-modification attack and providing copyright protection as well as suit for the characteristics of the P2P streaming system. After giving the detail algorithm, experiments show that the digital watermark achieves the goals of design in security, efficiency, integrity and transparency.

  2. P2P网贷与网购平台相结合的模式设计%Business Model of Combined Peer to Peer Lending Loan Platform and Online Shopping

    Institute of Scientific and Technical Information of China (English)

    韩天明; 孟艳华

    2014-01-01

    通过比较一种新型的互联网金融业务---P2 P个人网络借贷的三种典型运作模式,发现P2 P网贷在我国出现了变异,已经不是本来意义上的个人对个人的信用模式。借鉴余额宝和阿里小贷的成功经验,提出一种将网贷与网购平台相结合的业务模式,该模式具有交易成本低、收益率高、服务人数广泛、业务模式清晰、法律风险小等多种优点,可以实现多方共赢。%Peer to peer ( P2P) lending is an emerging Internet financial business.By comparing the typical three kinds of operation mode , it is found that P2P lending has deviated from its original sense , that is, person to person credit mode.Meanwhile , referring to the success of YuEbao and Ali micro-credit , a new business model which combines P2P lending platform with online shopping platform is explored.This business model has so many advantages , such as low transaction costs , high income rate , wide-ranging service , clear business framework, low legal risk and so on , which will create a win-win situation for the participants.

  3. Filtering in Hybrid Dynamic Bayesian Networks

    Science.gov (United States)

    Andersen, Morten Nonboe; Andersen, Rasmus Orum; Wheeler, Kevin

    2000-01-01

    We implement a 2-time slice dynamic Bayesian network (2T-DBN) framework and make a 1-D state estimation simulation, an extension of the experiment in (v.d. Merwe et al., 2000) and compare different filtering techniques. Furthermore, we demonstrate experimentally that inference in a complex hybrid DBN is possible by simulating fault detection in a watertank system, an extension of the experiment in (Koller & Lerner, 2000) using a hybrid 2T-DBN. In both experiments, we perform approximate inference using standard filtering techniques, Monte Carlo methods and combinations of these. In the watertank simulation, we also demonstrate the use of 'non-strict' Rao-Blackwellisation. We show that the unscented Kalman filter (UKF) and UKF in a particle filtering framework outperform the generic particle filter, the extended Kalman filter (EKF) and EKF in a particle filtering framework with respect to accuracy in terms of estimation RMSE and sensitivity with respect to choice of network structure. Especially we demonstrate the superiority of UKF in a PF framework when our beliefs of how data was generated are wrong. Furthermore, we investigate the influence of data noise in the watertank simulation using UKF and PFUKD and show that the algorithms are more sensitive to changes in the measurement noise level that the process noise level. Theory and implementation is based on (v.d. Merwe et al., 2000).

  4. Hybrid algorithm: A cost efficient solution for ONU placement in Fiber-Wireless (FiWi) network

    Science.gov (United States)

    Bhatt, Uma Rathore; Chouhan, Nitin; Upadhyay, Raksha

    2015-03-01

    Fiber-Wireless (FiWi) network is a promising access technology as it integrates the technical merits of optical and wireless access networks. FiWi provides large bandwidth and high stability of optical network and lower cost of wireless network respectively. Therefore, FiWi gives users to access broadband services in an "anywhere-anytime" way. One of the key issues in FiWi network is its deployment cost, which depends on the number of ONUs in the network. Therefore optimal placement of ONUs is desirable to design a cost effective network. In this paper, we propose an algorithm for optimal placement of ONUs. First we place an ONU in the center of each grid then we form a set of wireless routers associated with each ONU according to wireless hop number. The number of ONUs are minimized in such a way, that all the wireless routers can communicate to at least one of the ONUs. The number of ONUs in the network further reduced by using genetic algorithm. The effectiveness of the proposed algorithm is tested by considering Internet traffic as well as peer-to-peer (p2p) traffic in the network, which is a current need. Simulation results show that the proposed algorithm is better than existing algorithms in minimizing number of ONUs in the network for both types of traffics. Hence proposed algorithm offers cost effective solution to design the FiWi network.

  5. Ontology-Based Peer Exchange Network (OPEN)

    Science.gov (United States)

    Dong, Hui

    2010-01-01

    In current Peer-to-Peer networks, distributed and semantic free indexing is widely used by systems adopting "Distributed Hash Table" ("DHT") mechanisms. Although such systems typically solve a. user query rather fast in a deterministic way, they only support a very narrow search scheme, namely the exact hash key match. Furthermore, DHT systems put…

  6. Ontology-Based Peer Exchange Network (OPEN)

    Science.gov (United States)

    Dong, Hui

    2010-01-01

    In current Peer-to-Peer networks, distributed and semantic free indexing is widely used by systems adopting "Distributed Hash Table" ("DHT") mechanisms. Although such systems typically solve a. user query rather fast in a deterministic way, they only support a very narrow search scheme, namely the exact hash key match. Furthermore, DHT systems put…

  7. Social Dynamics within Electronic Networks of Practice

    Science.gov (United States)

    Mattson, Thomas A., Jr.

    2013-01-01

    Electronic networks of practice (eNoP) are special types of electronic social structures focused on discussing domain-specific problems related to a skill-based craft or profession in question and answer style forums. eNoP have implemented peer-to-peer feedback systems in order to motivate future contributions and to distinguish contribution…

  8. A novel approach to smart grid technology for electrical power transmission lines by a self-organized optical network node based on optical bistability

    Science.gov (United States)

    Nakanishi, Soichiro; Sasaki, Wakao

    2011-01-01

    In this work, we have demonstrated a new smart grid model by our novel green photonics technology based on selforganized optical networks realizing an autonomous peer-to-peer electric power transmissions without centralized control for the power grid. In this optical network, we introduced an adaptive algorithm for concurrent peer-to-peer communications, by utilizing optical nonlinearity depending only on the signal strength passing through the network. This method is applicable for autonomous organization of functions for ad-hoc electric power distribution systems for the power grid. For this purpose, a simple optical- electrical hybrid bistable circuit composed of such as light emitting diode (LED) and photo diode (PD), has been incorporated into the network node. In the experiment, the method uses a simple, local adaptation of transmission weights at each network node, which enables self-organizing functions of the network, such as self-routing, self-optimization, self-recovery and self-protection. Based on this method, we have demonstrated experimentally a new smart grid model applicable for ad-hoc electric power distribution systems mediated by power comsumptions. In this model, electric power flow is controlled autonomously through the self-organized network nodes associated with individual power facilities having photovoltaics and electric storage devices, etc., and the nodes convert the amounts of electric power supply and/or comsumption to the light intensity values using above mentioned transmission weights at each node. As a consequence, we have experimentally demonstrated a simple shorthaul system model for ad-hoc electric power distribution with a self-organized optical network as a novel green photonics technology application for smart grid.

  9. High availability of hybrid wireless networks

    Science.gov (United States)

    Leitgeb, Erich; Gebhart, Michael; Birnbacher, Ulla; Kogler, Wolfgang; Schrotter, Peter

    2004-09-01

    Free Space Optical (FSO) links offer high bandwidth and the flexibility of wireless communication links. However, the availability of FSO links is limited by weather patterns like fog and heavy snowfall. Microwave based communication links operating at high frequencies (40 - 43 GHz) have similar characteristics like high data rates and needed line-of-sight. Link availability for microwave systems is limited by heavy rain. Combining FSO links with microwave links within a hybrid FSO/microwave communication network has the advantage of added redundancy and higher link availability. Measurements over a period of one year show a combined availability of 99.93% for the climatic region of Graz, Austria) which proves that the combination of both technologies leads to a highly available wireless connection offering high bandwidth.

  10. Capacity analysis of inhomogeneous hybrid wireless networks using directional antennas

    Institute of Scientific and Technical Information of China (English)

    WU Feng; ZHU Jiang; TIAN Yi-long; ZOU Jian-bin

    2016-01-01

    Most of studies on network capacity are based on the assumption that all the nodes are uniformly distributed, which means that the networks are characterized by homogeneity. However, many realistic networks exhibit inhomogeneity due to natural and man-made reasons. In this work, the capacity of inhomogeneous hybrid networks with directional antennas for the first time is studied. By setting different node distribution probabilities, the whole network can be devided into dense cells and sparse cells. On this basis, an inhomogeneous hybrid network model is proposed. The network can exhibit significant inhomogeneity due to the coexistence of two types of cells. Then, we derive the network capacity and maximize the capacity under different channel allocation schemes. Finally, how the network parameters influence the network capacity is analyzed. It is found that if there are plenty of base stations, the per-node throughput can achieve constant order, and if the beamwidth of directional antenna is small enough, the network capacity can scale.

  11. Filtering in Hybrid Dynamic Bayesian Networks

    Science.gov (United States)

    Andersen, Morten Nonboe; Andersen, Rasmus Orum; Wheeler, Kevin

    2004-01-01

    We demonstrate experimentally that inference in a complex hybrid Dynamic Bayesian Network (DBN) is possible using the 2 - T i e Slice DBN (2T-DBN) from [Koller & Lerner, 20001 to model fault detection in a watertank system. In [Koller & Lerner, 20001 a generic Particle Filter (PF) is used for inference. We extend the experiment and perform approximate inference using The Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). Furthermore, we combine these techniques in a 'non-strict' Rao-Blackwellisation framework and apply it to the watertank system. We show that UKF and UKF in a PF framework outperfom the generic PF, EKF and EKF in a PF framework with respect to accuracy and robustness in terms of estimation RMSE. Especially we demonstrate the superiority of UKF in a PF framework when our beliefs of how data was generated are wrong. We also show that the choice of network structure is very important for the performance of the generic PF and the EKF algorithms, but not for the UKF algorithms. Furthermore, we investigate the influence of data noise in the water[ank simulation. Theory and implementation is based on the theory presented.

  12. Identification of hybrid node and link communities in complex networks

    Science.gov (United States)

    He, Dongxiao; Jin, Di; Chen, Zheng; Zhang, Weixiong

    2015-03-01

    Identifying communities in complex networks is an effective means for analyzing complex systems, with applications in diverse areas such as social science, engineering, biology and medicine. Finding communities of nodes and finding communities of links are two popular schemes for network analysis. These schemes, however, have inherent drawbacks and are inadequate to capture complex organizational structures in real networks. We introduce a new scheme and an effective approach for identifying complex mixture structures of node and link communities, called hybrid node-link communities. A central piece of our approach is a probabilistic model that accommodates node, link and hybrid node-link communities. Our extensive experiments on various real-world networks, including a large protein-protein interaction network and a large network of semantically associated words, illustrated that the scheme for hybrid communities is superior in revealing network characteristics. Moreover, the new approach outperformed the existing methods for finding node or link communities separately.

  13. Hybrid Neural Network Architecture for On-Line Learning

    CERN Document Server

    Chen, Yuhua; Wang, Lei

    2008-01-01

    Approaches to machine intelligence based on brain models have stressed the use of neural networks for generalization. Here we propose the use of a hybrid neural network architecture that uses two kind of neural networks simultaneously: (i) a surface learning agent that quickly adapt to new modes of operation; and, (ii) a deep learning agent that is very accurate within a specific regime of operation. The two networks of the hybrid architecture perform complementary functions that improve the overall performance. The performance of the hybrid architecture has been compared with that of back-propagation perceptrons and the CC and FC networks for chaotic time-series prediction, the CATS benchmark test, and smooth function approximation. It has been shown that the hybrid architecture provides a superior performance based on the RMS error criterion.

  14. Measurement campaign on connectivity of mesh networks formed by mobile devices

    DEFF Research Database (Denmark)

    Pietrarca, Beatrice; Sasso, Giovanni; Perrucci, Gian Paolo

    2007-01-01

    This paper reports the results of a measurement campaign on the connectivity level of mobile devices using Bluetooth (BT) to form cooperative mobile mesh networks. Such mobile mesh networks composed of mobile devices are the basis for any peer-to-peer communication like wireless grids or social...

  15. Online Networks as Societies: User Behaviors and Contribution Incentives

    NARCIS (Netherlands)

    Jia, L.

    2013-01-01

    Online networks like email, Facebook, LinkedIn, Wikipedia, eBay, and BitTorrent-like Peer-to-Peer (P2P) systems have become popular and powerful infrastructures for communication. They involve potentially large numbers of humans with their collective inputs and decisions, and they often rely on the

  16. Online Networks as Societies: User Behaviors and Contribution Incentives

    NARCIS (Netherlands)

    Jia, L.

    2013-01-01

    Online networks like email, Facebook, LinkedIn, Wikipedia, eBay, and BitTorrent-like Peer-to-Peer (P2P) systems have become popular and powerful infrastructures for communication. They involve potentially large numbers of humans with their collective inputs and decisions, and they often rely on the

  17. 基于马尔科夫链的60 GHz 点对点通信移动性优化%Improved 60 GHz peer to peer communications of mobile devices based on Markov chain

    Institute of Scientific and Technical Information of China (English)

    周扬; 郝鹏; 刘维亭; 邢倩; 李俊

    2013-01-01

    Since 60 GHz communications may have signal attenuation up to 20 dB,the working distance and qual-ity of the communications will be suffered .The beamforming technology has been introduced to improve the dis-tance and quality of the communications by making a beam propagate in a certain direction with increased signal strength .Meanwhile , the mobility of the device may also cause communication interruption according to the peer to peer communication according to the IEEE 802.11ad standard.In order to ensure the communication , we pro-pose an algorithm to improve the process of beamforming by predicting the next location of the mobile device based on Markov Chain .This algorithm provides both the location and beam rotation angle of the mobile device . Moreover , it takes the place of sector level sweep part of beamforming .Simulation shows the number of ex-changed messages between two devices has been decreased about 60% compared with the beamforming in the standard .%由于60 GHz通信在空气中可能会有高达20 dB的信号衰减,因此通信的范围和质量都可能受到影响.为此,IEEE 802.11 ad标准引入了能够定向增强信号和控制信号传播方向的波束成形技术来提高通信质量.然而,设备位置移动对波束成形的影响较大,它可能会导致通信质量下降甚至中断.为保证通信通畅,文中针对IEEE 802.11ad定义的点对点场景提出了波束成形优化算法.该算法基于马尔科夫链模型预测下一时刻设备的位置,并且提前调整相应的波束方向.该算法利用动态设备的相对位置和波束转动角度信息,代替了原波束成形方法中的波束扫描等过程.在仿真实验中,通过信息交互次数验证了该算法的有效性,提高了波束成形过程的效率,并且使该过程中的能量消耗降低了60%.

  18. On hybrid cooperation in underlay cognitive radio networks

    KAUST Repository

    Mahmood, Nurul Huda

    2012-11-01

    In wireless systems where transmitters are subject to a strict received power constraint, such as in underlay cognitive radio networks, cooperative communication is a promising strategy to enhance network performance, as it helps to improve the coverage area and outage performance of a network. However, this comes at the expense of increased resource utilization. To balance the performance gain against the possible over-utilization of resources, we propose a hybrid-cooperation technique for underlay cognitive radio networks, where secondary users cooperate only when required. Various performance measures of the proposed hybrid-cooperation technique are analyzed in this paper, and are also further validated numerically. © 2012 IEEE.

  19. Software architecture for hybrid electrical/optical data center network

    DEFF Research Database (Denmark)

    Mehmeri, Victor; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2016-01-01

    This paper presents hardware and software architecture based on Software-Defined Networking (SDN) paradigm and OpenFlow/NETCONF protocols for enabling topology management of hybrid electrical/optical switching data center networks. In particular, a development on top of SDN open-source controller...... OpenDaylight is presented to control an optical switching matrix based on Micro-Electro-Mechanical System (MEMS) technology.......This paper presents hardware and software architecture based on Software-Defined Networking (SDN) paradigm and OpenFlow/NETCONF protocols for enabling topology management of hybrid electrical/optical switching data center networks. In particular, a development on top of SDN open-source controller...

  20. Hybrid Wavelength Routed and Optical Packet Switched Ring Networks for the Metropolitan Area Network

    DEFF Research Database (Denmark)

    Nord, Martin

    2005-01-01

    Increased data traffic in the metropolitan area network calls for new network architectures. This paper evaluates optical ring architectures based on optical packet switching, wavelength routing, and hybrid combinations of the two concepts. The evaluation includes overall throughput and fairness...

  1. ABOUT HYBRID BIDIRECTIONAL ASSOCIATIVE MEMORY NEURAL NETWORKS WITH DISCRETE DELAYS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, hybrid bidirectional associative memory neural networks with discrete delays is considered. By ingeniously importing real parameters di > 0(i = 1,2,···,n) which can be adjusted, we establish some new sufficient conditions for the dynamical characteristics of hybrid bidirectional associative memory neural networks with discrete delays by the method of variation of parameters and some analysis techniques. Our results generalize and improve the related results in [10,11]. Our work is significant...

  2. Small-Firm Networks: hybrid arrangement or organizational form?

    OpenAIRE

    Verschoore,Jorge Renato; Balestrin,Alsones; Perucia,Alexandre

    2014-01-01

    In the field of organizations, one relevant question is whether or not to consider networks as organizational forms. On the one hand, Williamson (1985) says that networks are hybrid arrangements. On the other, authors like Powell (1990) argue that networks constitute themselves as organizational forms. Given this dilemma, the present article proposes the analysis of organizational characteristics of small-firm networks (SFN). To reach such objective, twelve SFNs in distinct stages of developm...

  3. On the Capacity of Hybrid Wireless Networks with Opportunistic Routing

    Directory of Open Access Journals (Sweden)

    Tan Le

    2010-01-01

    Full Text Available This paper studies the capacity of hybrid wireless networks with opportunistic routing (OR. We first extend the opportunistic routing algorithm to exploit high-speed data transmissions in infrastructure network through base stations. We then develop linear programming models to calculate the end-to-end throughput bounds from multiple source nodes to single as well as multiple destination nodes. The developed models are applied to study several hybrid wireless network examples. Through case studies, we investigate several factors that have significant impacts on the hybrid wireless network capacity under opportunistic routing, such as node transmission range, density and distribution pattern of base stations (BTs, and number of wireless channels on wireless nodes and base stations. Our numerical results demonstrate that opportunistic routing could achieve much higher throughput on both ad hoc and hybrid networks than traditional unicast routing (UR. Moreover, opportunistic routing can efficiently utilize base stations and achieve significantly higher throughput gains in hybrid wireless networks than in pure ad hoc networks especially with multiple-channel base stations.

  4. Des vertus culturelles du piratage à l’ère numérique : ou comment le peer-to-peer peut contribuer à la circulation du patrimoine québécois et à la diversité culturelle

    OpenAIRE

    Tétu, Martin

    2013-01-01

    Ce texte traite de piratage en ligne à travers la pratique du peer-to-peer au Québec, c’est-à-dire une forme d’échange non autorisé de produits culturels sur Internet (pratique appelée « piratage culturel »). Une approche strictement juridique de la pratique y voit un simple détournement de copyright, tandis que d’autres approches (mouvement Copyleft, Parti pirate, etc.) postulent qu’un gain social est généré par une telle circulation de l’information à grande échelle. Peu de recherches empir...

  5. Thermodynamics of Large-Scale Heterogeneous Wireless Networks

    Science.gov (United States)

    2014-03-06

    cost-effective sensor networks for monitoring and surveillance, peer-to-peer networks between handheld devices in a social setup, among others. A...communication gains (up to a constant factor) are feasible even with unsynchronized relay nodes. III. IN-NETWORK COMPUTATION In many networks, such as sensor ...existing WiFi networks in large public area 3 (or even at home), such a problem is attempted to solve by means of the medium access protocol like the

  6. 新型双重混合的流媒体直播系统架构%Novel Double Hybrid Architecture of Live Video Streaming System

    Institute of Scientific and Technical Information of China (English)

    黄思嘉; 吕智慧; 吴杰

    2011-01-01

    Based on Content Delivery Network(CDN) and Peer-to-Peer network(P2P), this paper designs a new double hybrid architecture of live video streaming system. based on research of hybrid CDN-P2P network, which are hybrid CDN-P2P, and hybrid Tree-Mesh. Mainly Elaborate the system architecture, construct of CoreTree and peer selection algorithm. And through the system simulation, result shows that this system has low delay of playing and starting than other popular architectures.%研究内容分发网络(CDN)与对等网络(P2P)的混合模型,提出一种CDN与P2P、树形结构与网状结构双重混合的流媒体直播系统架构.设计基于CDN-P2P的树网结合直播系统模型,阐述核心树的主要构建机制,介绍网状结构的节点选择算法.系统仿真结果表明,与纯P2P模型及CDN-P2P混合模型相比,该系统的播放和启动延迟较小.

  7. Epidemics and rumours in complex networks

    CERN Document Server

    Draief, Moez

    2009-01-01

    Information propagation through peer-to-peer systems, online social systems, wireless mobile ad hoc networks and other modern structures can be modelled as an epidemic on a network of contacts. Understanding how epidemic processes interact with network topology allows us to predict ultimate course, understand phase transitions and develop strategies to control and optimise dissemination. This book is a concise introduction for applied mathematicians and computer scientists to basic models, analytical tools and mathematical and algorithmic results. Mathematical tools introduced include coupling

  8. Fastest Distributed Consensus on Star-Mesh Hybrid Sensor Networks

    CERN Document Server

    Jafarizadeh, Saber

    2010-01-01

    Solving Fastest Distributed Consensus (FDC) averaging problem over sensor networks with different topologies has received some attention recently and one of the well known topologies in this issue is star-mesh hybrid topology. Here in this work we present analytical solution for the problem of FDC algorithm by means of stratification and semidefinite programming, for the Star-Mesh Hybrid network with K-partite core (SMHK) which has rich symmetric properties. Also the variations of asymptotic and per step convergence rate of SMHK network versus its topological parameters have been studied numerically.

  9. On Hybrid Cooperation in Underlay Cognitive Radio Networks

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Yilmaz, Ferkan; Øien, Geir E.;

    2013-01-01

    of opportunistic wireless systems such as cognitive radio networks. In order to balance the performance gains from cooperative communication against the possible over-utilization of resources, we propose and analyze an adaptive-cooperation technique for underlay cognitive radio networks, termed as hybrid......-cooperation. Under the proposed cooperation scheme, secondary users in a cognitive radio network cooperate adaptively to enhance the spectral efficiency and the error performance of the network. The bit error rate, the spectral efficiency and the outage performance of the network under the proposed hybrid......Cooperative communication is a promising strategy to enhance the performance of a communication network as it helps to improve the coverage area and the outage performance. However, such enhancement comes at the expense of increased resource utilization, which is undesirable; more so in the case...

  10. Hybrid evolving clique-networks and their communicability

    Science.gov (United States)

    Ding, Yimin; Zhou, Bin; Chen, Xiaosong

    2014-08-01

    Aiming to understand real-world hierarchical networks whose degree distributions are neither power law nor exponential, we construct a hybrid clique network that includes both homogeneous and inhomogeneous parts, and introduce an inhomogeneity parameter to tune the ratio between the homogeneous part and the inhomogeneous one. We perform Monte-Carlo simulations to study various properties of such a network, including the degree distribution, the average shortest-path-length, the clustering coefficient, the clustering spectrum, and the communicability.

  11. Technologies for Home Networking

    DEFF Research Database (Denmark)

    A broad overview of the home networking field, ranging from wireless technologies to practical applications. In the future, it is expected that private networks (e.g. home networks) will become part of the global network ecosystem, participating in sharing their own content, running IP......-based services and possibly becoming service providers themselves. This is already happening in the so-called "social networks" and peer-to-peer file sharing networks on the Internet - making this emerging topic one of the most active research areas in the wireless communications filed....

  12. Bio-Inspired Energy-Aware Protocol Design for Cooperative Wireless Networks

    DEFF Research Database (Denmark)

    Perrucci, Gian Paolo; Anggraeni, Puri Novelti; Wardana, Satya Ardhy;

    2011-01-01

    In this work, bio-inspired cooperation rules are applied to wireless communication networks. The main goal is to derive cooperative behaviour rules to improve the energy consumption of each mobile device. A medium access control (MAC) protocol particularly designed for peer-to-peer communication ...

  13. Hybrid CDN structure with a P2P based streaming protocol

    CERN Document Server

    Pushp, Saumay

    2010-01-01

    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 ...

  14. On Hybrid Cooperation in Underlay Cognitive Radio Networks

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Yilmaz, Ferkan; Øien, Geir E.

    2013-01-01

    of opportunistic wireless systems such as cognitive radio networks. In order to balance the performance gains from cooperative communication against the possible over-utilization of resources, we propose and analyze an adaptive-cooperation technique for underlay cognitive radio networks, termed as hybrid......-cooperation. Under the proposed cooperation scheme, secondary users in a cognitive radio network cooperate adaptively to enhance the spectral efficiency and the error performance of the network. The bit error rate, the spectral efficiency and the outage performance of the network under the proposed hybrid...... cooperation scheme with amplify-and-forward relaying are analyzed in this paper, and compared against conventional cooperation technique. Findings of the analytical performance analyses are further validated numerically through selected computer-based Monte-Carlo simulations. The proposed scheme is found...

  15. Design of Hybrid Mobile Communication Networks for Planetary Exploration

    Science.gov (United States)

    Alena, Richard L.; Ossenfort, John; Lee, Charles; Walker, Edward; Stone, Thom

    2004-01-01

    The Mobile Exploration System Project (MEX) at NASA Ames Research Center has been conducting studies into hybrid communication networks for future planetary missions. These networks consist of space-based communication assets connected to ground-based Internets and planetary surface-based mobile wireless networks. These hybrid mobile networks have been deployed in rugged field locations in the American desert and the Canadian arctic for support of science and simulation activities on at least six occasions. This work has been conducted over the past five years resulting in evolving architectural complexity, improved component characteristics and better analysis and test methods. A rich set of data and techniques have resulted from the development and field testing of the communication network during field expeditions such as the Haughton Mars Project and NASA Mobile Agents Project.

  16. Architectural improvements and 28 nm FPGA implementation of the APEnet+ 3D Torus network for hybrid HPC systems

    CERN Document Server

    Ammendola, Roberto; Frezza, Ottorino; Cicero, Francesca Lo; Paolucci, Pier Stanislao; Lonardo, Alessandro; Rossetti, Davide; Simula, Francesco; Tosoratto, Laura; Vicini, Piero

    2013-01-01

    Modern Graphics Processing Units (GPUs) are now considered accelerators for general purpose computation. A tight interaction between the GPU and the interconnection network is the strategy to express the full potential on capability computing of a multi-GPU system on large HPC clusters; that is the reason why an efficient and scalable interconnect is a key technology to finally deliver GPUs for scientific HPC. In this paper we show the latest architectural and performance improvement of the APEnet+ network fabric, a FPGA-based PCIe board with 6 fully bidirectional off-board links with 34 Gbps of raw bandwidth per direction, and X8 Gen2 bandwidth towards the host PC. The board implements a Remote Direct Memory Access (RDMA) protocol that leverages upon peer-to-peer (P2P) capabilities of Fermi- and Kepler-class NVIDIA GPUs to obtain real zero-copy, low-latency GPU-to-GPU transfers. Finally, we report on the development activities for 2013 focusing on the adoption of the latest generation 28 nm FPGAs and the pre...

  17. Architectural improvements and 28 nm FPGA implementation of the APEnet+ 3D Torus network for hybrid HPC systems

    Science.gov (United States)

    Ammendola, Roberto; Biagioni, Andrea; Frezza, Ottorino; Lo Cicero, Francesca; Stanislao Paolucci, Pier; Lonardo, Alessandro; Rossetti, Davide; Simula, Francesco; Tosoratto, Laura; Vicini, Piero

    2014-06-01

    Modern Graphics Processing Units (GPUs) are now considered accelerators for general purpose computation. A tight interaction between the GPU and the interconnection network is the strategy to express the full potential on capability computing of a multi-GPU system on large HPC clusters; that is the reason why an efficient and scalable interconnect is a key technology to finally deliver GPUs for scientific HPC. In this paper we show the latest architectural and performance improvement of the APEnet+ network fabric, a FPGA-based PCIe board with 6 fully bidirectional off-board links with 34 Gbps of raw bandwidth per direction, and X8 Gen2 bandwidth towards the host PC. The board implements a Remote Direct Memory Access (RDMA) protocol that leverages upon peer-to-peer (P2P) capabilities of Fermi- and Kepler-class NVIDIA GPUs to obtain real zero-copy, low-latency GPU-to-GPU transfers. Finally, we report on the development activities for 2013 focusing on the adoption of the latest generation 28 nm FPGAs and the preliminary tests performed on this new platform.

  18. MULTIMEDIA ON GEOGRAPHIC NETWORK

    OpenAIRE

    Merlanti, Danilo

    2012-01-01

    In this thesis we investigate the topic of the multimedia contents distribution on a geo- graphic network which is a rarefied and huge field. First of all we have to classify the main parts necessary in the multimedia distribution on a geographic network. The main aspects of a geographic network that will be highlighted in this thesis are: the mechanism used to retrieve the sources of the multimedia content; in the case of the peer-to-peer network on geographic network one of t...

  19. Existing PON Infrastructure Supported Hybrid Fiber-Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Yu, Xianbin; Zhao, Ying; Deng, Lei;

    2012-01-01

    We propose a hybrid fiber wireless sensor network based on the existing PON infrastructure. The feasibility of remote sensing and PON convergence is experimentally proven by transmitting direct-sequence spread-spectrum wireless sensing and 2.5Gbps GPON signals.......We propose a hybrid fiber wireless sensor network based on the existing PON infrastructure. The feasibility of remote sensing and PON convergence is experimentally proven by transmitting direct-sequence spread-spectrum wireless sensing and 2.5Gbps GPON signals....

  20. Hybrid positioning with lighting LEDs and Zigbee multihop wireless network

    Science.gov (United States)

    Lee, Y. U.; Baang, S.; Park, J.; Zhou, Z.; Kavehrad, M.

    2012-01-01

    A simple, accurate, secure, long-lasting, and portable hybrid positioning system is proposed and designed in this paper. It consists of a lighting LED that generates visible light data corresponding to position information of a target and a Zigbee wireless network communication module with low power, security, and service area expansion characteristics. Under an indoor environment where there is 23.62m distance between an observer and the target, the presented hybrid positioning system is tested and is verified with the functions of Zigbee three hop wireless networking and visible light communication (VLC) scheme. The test results are analyzed and discussed.

  1. The research of controller area network on hybrid electrical vehicle

    Institute of Scientific and Technical Information of China (English)

    Wu Hongxing; Song Liwei; Kou Baoquan; Cheng Shukang

    2006-01-01

    It is of increasing importance to design and implement vehicle networks for transferring information between electrical control units on Hybrid Electrical Vehicle (HEV). This paper presents a scheme of using Controller Area Network (CAN) technology to realize communication and datasharing between the electrical units on the HEV. The principle and communication protocol of Electrical Control Units (ECU) CAN node are introduced. By considering different sensitivity of the devices to the latency of data transportation, a new design procedure is proposed for the purpose of simplifying network codes and wiring harness, reducing assembly space and weight, improving assembly efficiency, and enhancing fault-diagnose in auto networks.

  2. 一种基于Windows Peer-to-Peer网络的VoIP系统及其实现%VoIP System Based on Windows Peer-to-Peer Networking

    Institute of Scientific and Technical Information of China (English)

    范先龙; 郭传雄; 迟学斌

    2006-01-01

    简要介绍了P2P网络和VoIP的技术背景,其中P2P主要涉及的是Windows Peer-to-Peer网络.提出一种新的基于P2P网络的VoIP系统解决方案,并给出具体实现.与现有的常见IM软件不同,使用了PNRP(对等名称解析协议)进行名称解析,不需要服务器的支持,具有P2P软件的特点.运行于Windows XP(SP1及以上版本)和Windows Mobile环境上,可以在局域网范围内进行语音和即时消息通信.

  3. Hybrid RRM Architecture for Future Wireless Networks

    DEFF Research Database (Denmark)

    Tragos, Elias; Mihovska, Albena D.; Mino, Emilio

    2007-01-01

    The concept of ubiquitous and scalable system is applied in the IST WINNER II [1] project to deliver optimum performance for different deployment scenarios from local area to wide area wireless networks. The integration of cellular and local area networks in a unique radio system will provide a g...

  4. Hybrid Distributed Iterative Capacity Allocation over Bluetooth Network

    DEFF Research Database (Denmark)

    Son, L.T.; Schiøler, Henrik; Madsen, Ole Brun

    With the current development of mobile devices, short range wireless communications have become more and more popular, and many researches on short range wireless communications, such as Bluetooth, have gained special interests, in industry as well as in academy. This paper analyzes capacity...... allocation issues in Bluetooth network as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. The hybrid distributed capacity allocation scheme is proposed as an approximated solution of the formulated problem that satisfies quality...... of service requirements and constraints in Bluetooth network, such as limited capacity, decentralized, frequent changes of topology and of capacities assigned to nodes in the network. The simulation shows that the performance of Bluetooth could be improved by applying the hybrid distributed iterative...

  5. Hybrid Distributed Iterative Capacity Allocation over Bluetooth Network

    DEFF Research Database (Denmark)

    Son, L.T.; Schiøler, Henrik; Madsen, Ole Brun

    2002-01-01

    With the current development of mobile devices, short range wireless communications have become more and more popular, and many researches on short range wireless communications, such as Bluetooth, have gained special interests, in industry as well as in academy. This paper analyzes capacity...... allocation issues in Bluetooth network as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. The hybrid distributed capacity allocation scheme is proposed as an approximated solution of the formulated problem that satisfies quality...... of service requirements and constraints in Bluetooth network, such as limited capacity, decentralized, frequent changes of topology and of capacities assigned to nodes in the network. The simulation shows that the performance of Bluetooth could be improved by applying the hybrid distributed iterative...

  6. ProofBook: An Online Social Network Based on Proof-of-Work and Friend-Propagation

    NARCIS (Netherlands)

    Biedermann, Sebastian; Karvelas, Nikolaos P.; Katzenbeisser, Stefan; Strufe, Thorsten; Peter, Andreas

    2014-01-01

    Online Social Networks (OSNs) enjoy high popularity, but their centralized architectures lead to intransparency and mistrust in the providers who can be the single point of failure. A solution is to adapt the OSN functionality to an underlying and fully distributed peer-to-peer (P2P) substrate.

  7. Scalable and Hybrid Radio Resource Management for Future Wireless Networks

    DEFF Research Database (Denmark)

    Mino, E.; Luo, Jijun; Tragos, E.;

    2007-01-01

    The concept of ubiquitous and scalable system is applied in the IST WINNER II [1] project to deliver optimum performance for different deployment scenarios, from local area to wide area wireless networks. The integration in a unique radio system of a cellular and local area type networks supposes...... describes a proposal for scalable and hybrid radio resource management to efficiently integrate the different WINNER system modes. Index...

  8. Leading school networks, hybrid leadership in action?

    OpenAIRE

    Townsend, Andrew

    2015-01-01

    A range of different constructs are used to describe and define the way that leadership operates in education settings. This range can be presented as binary categories of leadership, in which either one, or the other form of leadership is preferred, but not both. An example of this is the contrast made between solo and distributed leadership. A more sophisticated alternative has been proposed, which is to consider leadership as a hybrid activity, one which entails a range of approaches inspi...

  9. Final Technical Report for Terabit-scale hybrid networking project.

    Energy Technology Data Exchange (ETDEWEB)

    Veeraraghavan, Malathi [Univ. of Virginia, Charlottesville, VA (United States)

    2015-12-12

    This report describes our accomplishments and activities for the project titled Terabit-Scale Hybrid Networking. The key accomplishment is that we developed, tested and deployed an Alpha Flow Characterization System (AFCS) in ESnet. It is being run in production mode since Sept. 2015. Also, a new QoS class was added to ESnet5 to support alpha flows.

  10. Reverse engineering cellular decisions for hybrid reconfigurable network modeling

    Science.gov (United States)

    Blair, Howard A.; Saranak, Jureepan; Foster, Kenneth W.

    2011-06-01

    Cells as microorganisms and within multicellular organisms make robust decisions. Knowing how these complex cells make decisions is essential to explain, predict or mimic their behavior. The discovery of multi-layer multiple feedback loops in the signaling pathways of these modular hybrid systems suggests their decision making is sophisticated. Hybrid systems coordinate and integrate signals of various kinds: discrete on/off signals, continuous sensory signals, and stochastic and continuous fluctuations to regulate chemical concentrations. Such signaling networks can form reconfigurable networks of attractors and repellors giving them an extra level of organization that has resilient decision making built in. Work on generic attractor and repellor networks and on the already identified feedback networks and dynamic reconfigurable regulatory topologies in biological cells suggests that biological systems probably exploit such dynamic capabilities. We present a simple behavior of the swimming unicellular alga Chlamydomonas that involves interdependent discrete and continuous signals in feedback loops. We show how to rigorously verify a hybrid dynamical model of a biological system with respect to a declarative description of a cell's behavior. The hybrid dynamical systems we use are based on a unification of discrete structures and continuous topologies developed in prior work on convergence spaces. They involve variables of discrete and continuous types, in the sense of type theory in mathematical logic. A unification such as afforded by convergence spaces is necessary if one wants to take account of the affect of the structural relationships within each type on the dynamics of the system.

  11. Self-Healing Hybrid Protection Architecture for Passive Optical Networks

    Directory of Open Access Journals (Sweden)

    Waqas A. Imtiaz

    2015-08-01

    Full Text Available Expanding size of passive optical networks (PONs along with high availability expectation makes the reliability performance a crucial need. Most protection architectures utilize redundant network components to enhance network survivability, which is not economical. This paper proposes new self-healing protection architecture for passive optical networks (PONs, with a single ring topology and star-ring topology at feeder and distribution level respectively. The proposed architecture provides desirable protection to the network by avoiding fiber duplication at both feeder and distribution level. Moreover, medium access control (MAC controlled switching is utilized to provide efficient detection, and restoration of faults or cuts throughout the network. Analytical analysis reveals that the proposed self-healing hybrid protection architecture ensures survivability of the affected traffic along with desirable connection availability of 99.9994 % at minimum deployment cost, through simple architecture and simultaneous protection against failures.

  12. Nafion–clay hybrids with a network structure

    KAUST Repository

    Burgaz, Engin

    2009-05-01

    Nafion-clay hybrid membranes with a unique microstructure were synthesized using a fundamentally new approach. The new approach is based on depletion aggregation of suspended particles - a well-known phenomenon in colloids. For certain concentrations of clay and polymer, addition of Nafion solution to clay suspensions in water leads to a gel. Using Cryo-TEM we show that the clay particles in the hybrid gels form a network structure with an average cell size in the order of 500 nm. The hybrid gels are subsequently cast to produce hybrid Nafion-clay membranes. Compared to pure Nafion the swelling of the hybrid membranes in water and methanol is dramatically reduced while their selectivity (ratio of conductivity over permeability) increases. The small decrease of ionic conductivity for the hybrid membranes is more than compensated by the large decrease in methanol permeability. Lastly the hybrid membranes are much stiffer and can withstand higher temperatures compared to pure Nafion. Both of these characteristics are highly desirable for use in fuel cell applications, since a) they will allow the use of a thinner membrane circumventing problems associated with the membrane resistance and b) enable high temperature applications. © 2009 Elsevier Ltd. All rights reserved.

  13. Novel Hybrid Intrusion Detection System For Clustered Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Hichem Sedjelmaci

    2011-08-01

    Full Text Available Wireless sensor network (WSN is regularly deployed in unattended and hostile environments. The WSN isvulnerable to security threats and susceptible to physical capture. Thus, it is necessary to use effective mechanisms to protect the network. It is widely known, that the intrusion detection is one of the mostefficient security mechanisms to protect the network against malicious attacks or unauthorized access. In this paper, we propose a hybrid intrusion detection system for clustered WSN. Our intrusion framework uses a combination between the Anomaly Detection based on support vector machine (SVM and the Misuse Detection. Experiments results show that most of routing attacks can be detected with low falsealarm.

  14. Hybrid pre training algorithm of Deep Neural Networks

    Directory of Open Access Journals (Sweden)

    Drokin I. S.

    2016-01-01

    Full Text Available This paper proposes a hybrid algorithm of pre training deep networks, using both marked and unmarked data. The algorithm combines and extends the ideas of Self-Taught learning and pre training of neural networks approaches on the one hand, as well as supervised learning and transfer learning on the other. Thus, the algorithm tries to integrate in itself the advantages of each approach. The article gives some examples of applying of the algorithm, as well as its comparison with the classical approach to pre training of neural networks. These examples show the effectiveness of the proposed algorithm.

  15. SINET3: advanced optical and IP hybrid network

    Science.gov (United States)

    Urushidani, Shigeo

    2007-11-01

    This paper introduces the new Japanese academic backbone network called SINET3, which has been in full-scale operation since June 2007. SINET3 provides a wide variety of network services, such as multi-layer transfer, enriched VPN, enhanced QoS, and layer-1 bandwidth on demand (BoD) services to create an innovative and prolific science infrastructure for more than 700 universities and research institutions. The network applies an advanced hybrid network architecture composed of 75 layer-1 switches and 12 high-performance IP routers to accommodate such diversified services in a single network platform, and provides sufficient bandwidth using Japan's first STM256 (40 Gbps) lines. The network adopts lots of the latest networking technologies, such as next-generation SDH (VCAT/GFP/LCAS), GMPLS, advanced MPLS, and logical-router technologies, for high network convergence, flexible resource assignment, and high service availability. This paper covers the network services, network design, and networking technologies of SINET3.

  16. Electroencephalography epilepsy classifications using hybrid cuckoo search and neural network

    Science.gov (United States)

    Pratiwi, A. B.; Damayanti, A.; Miswanto

    2017-07-01

    Epilepsy is a condition that affects the brain and causes repeated seizures. This seizure is episodes that can vary and nearly undetectable to long periods of vigorous shaking or brain contractions. Epilepsy often can be confirmed with an electrocephalography (EEG). Neural Networks has been used in biomedic signal analysis, it has successfully classified the biomedic signal, such as EEG signal. In this paper, a hybrid cuckoo search and neural network are used to recognize EEG signal for epilepsy classifications. The weight of the multilayer perceptron is optimized by the cuckoo search algorithm based on its error. The aim of this methods is making the network faster to obtained the local or global optimal then the process of classification become more accurate. Based on the comparison results with the traditional multilayer perceptron, the hybrid cuckoo search and multilayer perceptron provides better performance in term of error convergence and accuracy. The purpose methods give MSE 0.001 and accuracy 90.0 %.

  17. Probabilistic Wind Power Forecasting with Hybrid Artificial Neural Networks

    DEFF Research Database (Denmark)

    Wan, Can; Song, Yonghua; Xu, Zhao

    2016-01-01

    probabilities of prediction errors provide an alternative yet effective solution. This article proposes a hybrid artificial neural network approach to generate prediction intervals of wind power. An extreme learning machine is applied to conduct point prediction of wind power and estimate model uncertainties...... via a bootstrap technique. Subsequently, the maximum likelihood estimation method is employed to construct a distinct neural network to estimate the noise variance of forecasting results. The proposed approach has been tested on multi-step forecasting of high-resolution (10-min) wind power using...... actual wind power data from Denmark. The numerical results demonstrate that the proposed hybrid artificial neural network approach is effective and efficient for probabilistic forecasting of wind power and has high potential in practical applications....

  18. Intelligent Hybrid Cluster Based Classification Algorithm for Social Network Analysis

    Directory of Open Access Journals (Sweden)

    S. Muthurajkumar

    2014-05-01

    Full Text Available In this paper, we propose an hybrid clustering based classification algorithm based on mean approach to effectively classify to mine the ordered sequences (paths from weblog data in order to perform social network analysis. In the system proposed in this work for social pattern analysis, the sequences of human activities are typically analyzed by switching behaviors, which are likely to produce overlapping clusters. In this proposed system, a robust Modified Boosting algorithm is proposed to hybrid clustering based classification for clustering the data. This work is useful to provide connection between the aggregated features from the network data and traditional indices used in social network analysis. Experimental results show that the proposed algorithm improves the decision results from data clustering when combined with the proposed classification algorithm and hence it is proved that of provides better classification accuracy when tested with Weblog dataset. In addition, this algorithm improves the predictive performance especially for multiclass datasets which can increases the accuracy.

  19. Image Cytometry Data From Breast Lesions Analyzed using Hybrid Networks.

    Science.gov (United States)

    Mat Sakim, H A; Mat Isa, N A; G Naguib, Raouf; Sherbet, Gajanan

    2005-01-01

    The treatment and therapy to be administered on breast cancer patients are dependent on the stage of the disease at time of diagnosis. It is therefore crucial to determine the stage at the earliest time possible. Tumor dissemination to axillary lymph nodes has been regarded as an indication of tumor aggression, thus the stage of the disease. Neural networks have been employed in many applications including breast cancer prognosis. The performance of the networks have often been quoted based on accuracy and mean squared error. In this paper, the performance of hybrid networks based on Multilayer Perceptron and Radial Basis Function networks to predict axillary lymph node involvement have been investigated. A measurement of how confident the networks are with respect to the results produced is also proposed. The input layer of the networks include four image cytometry features extracted from fine needle aspiration of breast lesions. The highest accuracy achieved by the hybrid networks was 69% only. However, most of the correctly predicted cases had a high confidence level.

  20. Energy efficiency in hybrid mobile and wireless networks

    Energy Technology Data Exchange (ETDEWEB)

    Ziaul Haq Abbas

    2012-07-01

    Wireless Internet access is almost pervasive nowadays, and many types of wireless networks can be used to access the Internet. However, along with this growth, there is an even greater concern about the energy consumption and efficiency of mobile devices as well as of the supporting networks, triggering the appearance of the concept of green communication. While some efforts have been made towards this direction, challenges still exist and need to be tackled from diverse perspectives. Cellular networks, WLANs, and ad hoc networks in the form of wireless mesh networks are the most popular technologies for wireless Internet access. The availability of such a variety of access networks has also paved the way to explore synergistic approaches for Internet access, leading to the concept of hybrid networks and relay communications. In addition, many mobile devices are being equipped with multiple interfaces, enabling them to operate in hybrid networks. In contrast, the improvements in the battery technology itself have not matched the pace of the emerging mobile applications. The situation becomes more sophisticated when a mobile device functions also as a relay node to forward other station's data. In the literature, energy efficiency of mobile devices has been addressed from various perspectives such as protocol-level efforts, battery management efforts, etc. However, there is little work on energy efficiency in hybrid mobile and wireless networks and devices with heterogeneous connections. For example, when there are multiple networks available to a mobile device, how to achieve optimum long-term energy consumption of such a device is an open question. Furthermore, in today's cellular networks, micro-, pico-, and femto-cells are the most popular network topologies in order to support high data rate services and high user density. With the growth of such small-cell solutions, the energy consumption of these networks is also becoming an important concern for operators

  1. Mobility-aware Hybrid Synchronization for Wireless Sensor Network

    DEFF Research Database (Denmark)

    Dnyaneshwar, Mantri; Prasad, Neeli R.; Prasad, Ramjee

    2015-01-01

    Random mobility of node causes the frequent changes in the network dynamics causing the increased cost in terms of energy and bandwidth. It needs the additional efforts to synchronize the activities of nodes during data collection and transmission in Wireless Sensor Networks (WSNs). A key challenge...... in maintaining the effective data collection and transmission is to schedule and synchronize the activities of the nodes with the global clock. This paper proposes the Mobility-aware Hybrid Synchronization Algorithm (MHS) which works on the formation of cluster based on spanning tree mechanism (SPT). Nodes used...... for formation of the network have random mobility and heterogeneous in terms of energy with static sink. The nodes in the cluster and cluster heads in the network are synchronized with the notion of global time scale. In the initial stage, the algorithm establishes the hierarchical structure of the network...

  2. Bandwidth Efficient Hybrid Synchronization for Wireless Sensor Network

    DEFF Research Database (Denmark)

    Dnyaneshwar, Mantri; Prasad, Neeli R.; Prasad, Ramjee

    2015-01-01

    Data collection and transmission are the fundamental operations of Wireless Sensor Networks (WSNs). A key challenge in effective data collection and transmission is to schedule and synchronize the activities of the nodes with the global clock. This paper proposes the Bandwidth Efficient Hybrid...... Synchronization Data Aggregation Algorithm (BESDA) using spanning tree mechanism (SPT). It uses static sink and mobile nodes in the network. BESDA considers the synchronization of a local clock of node with global clock of the network. In the initial stage algorithm established the hierarchical structure...... in the network and then perform the pair-wise synchronization. With the mobility of node, the structure frequently changes causing an increase in energy consumption. To mitigate the problem BESDA aggregate data with the notion of a global timescale throughout the network and schedule based time-division multiple...

  3. Hybrid recommendation methods in complex networks

    CERN Document Server

    Fiasconaro, A; Nicosia, V; Latora, V; Mantegna, R N

    2014-01-01

    We propose here two new recommendation methods, based on the appropriate normalization of already existing similarity measures, and on the convex combination of the recommendation scores derived from similarity between users and between objects. We validate the proposed measures on three relevant data sets, and we compare their performance with several recommendation systems recently proposed in the literature. We show that the proposed similarity measures allow to attain an improvement of performances of up to 20\\% with respect to existing non-parametric methods, and that the accuracy of a recommendation can vary widely from one specific bipartite network to another, which suggests that a careful choice of the most suitable method is highly relevant for an effective recommendation on a given system. Finally, we studied how an increasing presence of random links in the network affects the recommendation scores, and we found that one of the two recommendation algorithms introduced here can systematically outpe...

  4. Hybrid recommendation methods in complex networks

    Science.gov (United States)

    Fiasconaro, A.; Tumminello, M.; Nicosia, V.; Latora, V.; Mantegna, R. N.

    2015-07-01

    We propose two recommendation methods, based on the appropriate normalization of already existing similarity measures, and on the convex combination of the recommendation scores derived from similarity between users and between objects. We validate the proposed measures on three data sets, and we compare the performance of our methods to other recommendation systems recently proposed in the literature. We show that the proposed similarity measures allow us to attain an improvement of performances of up to 20% with respect to existing nonparametric methods, and that the accuracy of a recommendation can vary widely from one specific bipartite network to another, which suggests that a careful choice of the most suitable method is highly relevant for an effective recommendation on a given system. Finally, we study how an increasing presence of random links in the network affects the recommendation scores, finding that one of the two recommendation algorithms introduced here can systematically outperform the others in noisy data sets.

  5. Hybrid recommendation methods in complex networks.

    Science.gov (United States)

    Fiasconaro, A; Tumminello, M; Nicosia, V; Latora, V; Mantegna, R N

    2015-07-01

    We propose two recommendation methods, based on the appropriate normalization of already existing similarity measures, and on the convex combination of the recommendation scores derived from similarity between users and between objects. We validate the proposed measures on three data sets, and we compare the performance of our methods to other recommendation systems recently proposed in the literature. We show that the proposed similarity measures allow us to attain an improvement of performances of up to 20% with respect to existing nonparametric methods, and that the accuracy of a recommendation can vary widely from one specific bipartite network to another, which suggests that a careful choice of the most suitable method is highly relevant for an effective recommendation on a given system. Finally, we study how an increasing presence of random links in the network affects the recommendation scores, finding that one of the two recommendation algorithms introduced here can systematically outperform the others in noisy data sets.

  6. A hybrid neural network model for consciousness

    Institute of Scientific and Technical Information of China (English)

    蔺杰; 金小刚; 杨建刚

    2004-01-01

    A new framework for consciousness is introduced based upon traditional artificial neural network models. This framework reflects explicit connections between two parts of the brain: one global working memory and distributed modular cerebral networks relating to specific brain functions. Accordingly this framework is composed of three layers,physical mnemonic layer and abstract thinking layer,which cooperate together through a recognition layer to accomplish information storage and cognition using algorithms of how these interactions contribute to consciousness:(1)the reception process whereby cerebral subsystems group distributed signals into coherent object patterns;(2)the partial recognition process whereby patterns from particular subsystems are compared or stored as knowledge; and(3)the resonant learning process whereby global workspace stably adjusts its structure to adapt to patterns' changes. Using this framework,various sorts of human actions can be explained,leading to a general approach for analyzing brain functions.

  7. A hybrid neural network model for consciousness

    Institute of Scientific and Technical Information of China (English)

    蔺杰; 金小刚; 杨建刚

    2004-01-01

    A new framework for consciousness is introduced based upon traditional artificial neural network models. This framework reflects explicit connections between two parts of the brain: one global working memory and distributed modular cerebral networks relating to specific brain functions. Accordingly this framework is composed of three layers, physical mnemonic layer and abstract thinking layer, which cooperate together through a recognition layer to accomplish information storage and cognition using algorithms of how these interactions contribute to consciousness: (l) the reception process whereby cerebral subsystems group distributed signals into coherent object patterns; (2) the partial recognition process whereby patterns from particular subsystems are compared or stored as knowledge; and (3) the resonant learning process whereby global workspace stably adjusts its structure to adapt to patterns' changes. Using this framework, various sorts of human actions can be explained, leading to a general approach for analyzing brain functions.

  8. On hybrid cooperation in underlay cognitive radio networks

    KAUST Repository

    Mahmood, Nurul Huda

    2013-09-01

    Cooperative communication is a promising strategy to enhance the performance of a communication network as it helps to improve the coverage area and the outage performance. However, such enhancement comes at the expense of increased resource utilization, which is undesirable; more so in the case of opportunistic wireless systems such as cognitive radio networks. In order to balance the performance gains from cooperative communication against the possible over-utilization of resources, we propose and analyze an adaptive-cooperation technique for underlay cognitive radio networks, termed as hybrid-cooperation. Under the proposed cooperation scheme, secondary users in a cognitive radio network cooperate adaptively to enhance the spectral efficiency and the error performance of the network. The bit error rate, the spectral efficiency and the outage performance of the network under the proposed hybrid cooperation scheme with amplify-and-forward relaying are analyzed in this paper, and compared against conventional cooperation technique. Findings of the analytical performance analyses are further validated numerically through selected computer-based Monte-Carlo simulations. The proposed scheme is found to achieve significantly better performance in terms of the spectral efficiency and the bit error rate, compared to the conventional amplify-and-forward cooperation scheme. © 2013 IEEE.

  9. Hybrid Network Defense Model Based on Fuzzy Evaluation

    Directory of Open Access Journals (Sweden)

    Ying-Chiang Cho

    2014-01-01

    Full Text Available With sustained and rapid developments in the field of information technology, the issue of network security has become increasingly prominent. The theme of this study is network data security, with the test subject being a classified and sensitive network laboratory that belongs to the academic network. The analysis is based on the deficiencies and potential risks of the network’s existing defense technology, characteristics of cyber attacks, and network security technologies. Subsequently, a distributed network security architecture using the technology of an intrusion prevention system is designed and implemented. In this paper, first, the overall design approach is presented. This design is used as the basis to establish a network defense model, an improvement over the traditional single-technology model that addresses the latter’s inadequacies. Next, a distributed network security architecture is implemented, comprising a hybrid firewall, intrusion detection, virtual honeynet projects, and connectivity and interactivity between these three components. Finally, the proposed security system is tested. A statistical analysis of the test results verifies the feasibility and reliability of the proposed architecture. The findings of this study will potentially provide new ideas and stimuli for future designs of network security architecture.

  10. Learning by Knowledge Networking across Cultures

    DEFF Research Database (Denmark)

    Wangel, Arne; Stærdahl, Jens; Bransholm Pedersen, Kirsten

    2005-01-01

    some of the obstacles into resources for knowledge sharing. However, students have stressed their positive experience of cross-cultural communication. While a joint course of three week duration by itself may involve only limited cross-cultural learning, serving primarily as an introduction to a long...... in the field, negotiate and agree on the analysis, and sustain the exchange of knowledge, possibly through virtual peer-to-peer networking....

  11. PV-Diesel Hybrid SCADA Experiment Network Design

    Science.gov (United States)

    Kalu, Alex; Durand, S.; Emrich, Carol; Ventre, G.; Wilson, W.; Acosta, R.

    1999-01-01

    The essential features of an experimental network for renewable power system satellite based supervisory, control and data acquisition (SCADA) are communication links, controllers, diagnostic equipment and a hybrid power system. Required components for implementing the network consist of two satellite ground stations, to satellite modems, two 486 PCs, two telephone receivers, two telephone modems, two analog telephone lines, one digital telephone line, a hybrid-power system equipped with controller and a satellite spacecraft. In the technology verification experiment (TVE) conducted by Savannah State University and Florida Solar Energy Center, the renewable energy hybrid system is the Apex-1000 Mini-Hybrid which is equipped with NGC3188 for user interface and remote control and the NGC2010 for monitoring and basic control tasks. This power system is connected to a satellite modem via a smart interface, RS232. Commands are sent to the power system control unit through a control PC designed as PC1. PC1 is thus connected to a satellite model through RS232. A second PC, designated PC2, the diagnostic PC is connected to both satellite modems via separate analog telephone lines for checking modems'health. PC2 is also connected to PC1 via a telephone line. Due to the unavailability of a second ground station for the ACTS, one ground station is used to serve both the sending and receiving functions in this experiment. Signal is sent from the control PC to the Hybrid system at a frequency f(sub 1), different from f(sub 2), the signal from the hybrid system to the control PC. f(sub l) and f(sub 2) are sufficiently separated to avoid interference.

  12. Avatar Mobility in Networked Virtual Environments: Measurements, Analysis, and Implications

    CERN Document Server

    Liang, Huiguang; Neo, Ming Feng; Ooi, Wei Tsang; Motani, Mehul

    2008-01-01

    We collected mobility traces of 84,208 avatars spanning 22 regions over two months in Second Life, a popular networked virtual environment. We analyzed the traces to characterize the dynamics of the avatars mobility and behavior, both temporally and spatially. We discuss the implications of the our findings to the design of peer-to-peer networked virtual environments, interest management, mobility modeling of avatars, server load balancing and zone partitioning, client-side caching, and prefetching.

  13. Optimizing multimedia content delivery over next-generation optical networks

    OpenAIRE

    Di Pascale, Emanuele

    2015-01-01

    This thesis analyzes the performance of a Peer-to-Peer (P2P) multimedia content delivery system for a network architecture based on next-generation Passive Optical Networks (PONs). A PON is an optical access technology that is able to deliver high bandwidth capacities at a fraction of the cost of traditional point-to-point fiber solutions; this is achieved by sharing the same feeder fiber among several customers through the use of optical splitters. Established standards such as G...

  14. Trust Model for Social Network using Singular Value Decomposition

    OpenAIRE

    Davis Bundi Ntwiga; Patrick Weke; Michael Kiura Kirumbu

    2016-01-01

    For effective interactions to take place in a social network, trust is important. We model trust of agents using the peer to peer reputation ratings in the network that forms a real valued matrix. Singular value decomposition discounts the reputation ratings to estimate the trust levels as trust is the subjective probability of future expectations based on current reputation ratings. Reputation and trust are closely related and singular value decomposition can estimate trust using the...

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

    CERN Document Server

    Altman, Eitan; Shwartz, Adam; Xu, Yuedong

    2010-01-01

    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.

  16. Hybrid Networks and Risk Management in a System Perspective

    DEFF Research Database (Denmark)

    Nørgaard, Katrine

    new possibilities and new types of risk, as well as legal and ethical concerns. At the same time, the rapid acceleration and hybridization of the battlespace challenges the classical military bureaucracies and its legal-rational decision-making processes. This paper will address some of the legal...... intelligent, autonomous systems and human operators in multi-domain Battle Management Networks, (i.e Command, Control, Communications, Computer and Intelligence (C4I) networks/sensor grids). However, the incorporation of intelligent and autonomous weapon systems in complex military operations introduces both...

  17. Hybrid-source impedance network and its generalized cascading concepts

    DEFF Research Database (Denmark)

    Li, Ding; Gao, Feng; Loh, Poh Chiang;

    2009-01-01

    . It is anticipated that these concepts and their formed inverters can find applications in photovoltaic and other renewable systems, which in turn motivate the investigation initiated here on two-level and three-level generalized cascading concepts. In addition to their theoretical performance merits, practical......Hybrid-source impedance networks have attracted attention among researchers because of their flexibility in performing buck-boost energy conversion. To date, three distinct types of impedance networks can be summarized for implementing voltage-type inverters, with another three types summarized...

  18. A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks

    Science.gov (United States)

    Kerczewski, Robert J.; Chomos, Gerald J.; Griner, James H.; Mainger, Steven W.; Martzaklis, Konstantinos S.; Kachmar, Brian A.

    2000-01-01

    Rapid growth in air travel has been projected to continue for the foreseeable future. To maintain a safe and efficient national and global aviation system, significant advances in communications systems supporting aviation are required. Satellites will increasingly play a critical role in the aeronautical communications network. At the same time, current ground-based communications links, primarily very high frequency (VHF), will continue to be employed due to cost advantages and legacy issues. Hence a hybrid satellite-terrestrial network, or group of networks, will emerge. The increased complexity of future aeronautical communications networks dictates that system-level modeling be employed to obtain an optimal system fulfilling a majority of user needs. The NASA Glenn Research Center is investigating the current and potential future state of aeronautical communications, and is developing a simulation and modeling program to research future communications architectures for national and global aeronautical needs. This paper describes the primary requirements, the current infrastructure, and emerging trends of aeronautical communications, including a growing role for satellite communications. The need for a hybrid communications system architecture approach including both satellite and ground-based communications links is explained. Future aeronautical communication network topologies and key issues in simulation and modeling of future aeronautical communications systems are described.

  19. Dynamic Resource Allocation in Hybrid Access Femtocell Network

    Directory of Open Access Journals (Sweden)

    Afaz Uddin Ahmed

    2014-01-01

    Full Text Available Intercell interference is one of the most challenging issues in femtocell deployment under the coverage of existing macrocell. Allocation of resources between femtocell and macrocell is essential to counter the effects of interference in dense femtocell networks. Advances in resource management strategies have improved the control mechanism for interference reduction at lower node density, but most of them are ineffective at higher node density. In this paper, a dynamic resource allocation management algorithm (DRAMA for spectrum shared hybrid access OFDMA femtocell network is proposed. To reduce the macro-femto-tier interference and to improve the quality of service, the proposed algorithm features a dynamic resource allocation scheme by controlling them both centrally and locally. The proposed scheme focuses on Femtocell Access Point (FAP owners’ satisfaction and allows maximum utilization of available resources based on congestion in the network. A simulation environment is developed to study the quantitative performance of DRAMA in hybrid access-control femtocell network and compare it to closed and open access mechanisms. The performance analysis shows that higher number of random users gets connected to the FAP without compromising FAP owners’ satisfaction allowing the macrocell to offload a large number of users in a dense heterogeneous network.

  20. SIMULATION OF WIRELESS SENSOR NETWORK WITH HYBRID TOPOLOGY

    Directory of Open Access Journals (Sweden)

    J. Jaslin Deva Gifty

    2016-03-01

    Full Text Available The design of low rate Wireless Personal Area Network (WPAN by IEEE 802.15.4 standard has been developed to support lower data rates and low power consuming application. Zigbee Wireless Sensor Network (WSN works on the network and application layer in IEEE 802.15.4. Zigbee network can be configured in star, tree or mesh topology. The performance varies from topology to topology. The performance parameters such as network lifetime, energy consumption, throughput, delay in data delivery and sensor field coverage area varies depending on the network topology. In this paper, designing of hybrid topology by using two possible combinations such as star-tree and star-mesh is simulated to verify the communication reliability. This approach is to combine all the benefits of two network model. The parameters such as jitter, delay and throughput are measured for these scenarios. Further, MAC parameters impact such as beacon order (BO and super frame order (SO for low power consumption and high channel utilization, has been analysed for star, tree and mesh topology in beacon disable mode and beacon enable mode by varying CBR traffic loads.

  1. Doubly Optimal Secure Multicasting: Hierarchical Hybrid Communication Network : Disaster Relief

    CERN Document Server

    Garimella, Rama Murthy; Singhal, Deepti

    2011-01-01

    Recently, the world has witnessed the increasing occurrence of disasters, some of natural origin and others caused by man. The intensity of the phenomenon that cause such disasters, the frequency in which they occur, the number of people affected and the material damage caused by them have been growing substantially. Disasters are defined as natural, technological, and human-initiated events that disrupt the normal functioning of the economy and society on a large scale. Areas where disasters have occurred bring many dangers to rescue teams and the communication network infrastructure is usually destroyed. To manage these hazards, different wireless technologies can be launched in the area of disaster. This paper discusses the innovative wireless technologies for Disaster Management. Specifically, issues related to the design of Hierarchical Hybrid Communication Network (arising in the communication network for disaster relief) are discussed.

  2. BETTER SCALABLE ROUTING PROTOCOL FOR HYBRID WIRELESS MESH NETWORK

    Directory of Open Access Journals (Sweden)

    Debraj Modak

    2013-02-01

    Full Text Available There are many routing approaches have been borrowed from mobile ad hoc network to achieve routing solutions in wireless mesh network. WMN was developed for reliable data communication and load balancing. AODV provides loop-free routes even while repairing broken links. This paper have been proposed an improved hierarchical AODV routing protocol (IH-AODV, which exhibits better scalability and performance in the network. This IH-AODV protocol has been proposed for improvement in the scaling potential of AODV. MAODV allows each node in the network to send out multicast data packets, used for multicast traffic. The wireless mesh network architecture provides reduction in installation cost, large scale deployment, reliability and self management. It is mainly focused on implementing military or specialized civilian applications. Two protocols MAODV and IH-AODV were simulated using NS2 package. Simulation results will demonstrate that, IH-AODV scales well for large network and other metrics are also better than or comparable to MAODV in hybrid WMNs.

  3. Hybrid optical CDMA-FSO communications network under spatially correlated gamma-gamma scintillation

    DEFF Research Database (Denmark)

    Jurado-Navas, Antonio; Raddo, Thiago R.; Garrido-Balsells, José María

    2016-01-01

    In this paper, we propose a new hybrid network solution based on asynchronous optical code-division multiple-access (OCDMA) and free-space optical (FSO) technologies for last-mile access networks, where fiber deployment is impractical. The architecture of the proposed hybrid OCDMA-FSO network is ...

  4. Collaborative Multi-Layer Network Coding in Hybrid Cellular Cognitive Radio Networks

    KAUST Repository

    Moubayed, Abdallah J.

    2015-05-01

    In this paper, as an extension to [1], we propose a prioritized multi-layer network coding scheme for collaborative packet recovery in hybrid (interweave and underlay) cellular cognitive radio networks. This scheme allows the uncoordinated collaboration between the collocated primary and cognitive radio base-stations in order to minimize their own as well as each other\\'s packet recovery overheads, thus by improving their throughput. The proposed scheme ensures that each network\\'s performance is not degraded by its help to the other network. Moreover, it guarantees that the primary network\\'s interference threshold is not violated in the same and adjacent cells. Yet, the scheme allows the reduction of the recovery overhead in the collocated primary and cognitive radio networks. The reduction in the cognitive radio network is further amplified due to the perfect detection of spectrum holes which allows the cognitive radio base station to transmit at higher power without fear of violating the interference threshold of the primary network. For the secondary network, simulation results show reductions of 20% and 34% in the packet recovery overhead, compared to the non-collaborative scheme, for low and high probabilities of primary packet arrivals, respectively. For the primary network, this reduction was found to be 12%. © 2015 IEEE.

  5. RH+: A Hybrid Localization Algorithm for Wireless Sensor Networks

    Science.gov (United States)

    Basaran, Can; Baydere, Sebnem; Kucuk, Gurhan

    Today, localization of nodes in Wireless Sensor Networks (WSNs) is a challenging problem. Especially, it is almost impossible to guarantee that one algorithm giving optimal results for one topology will give optimal results for any other random topology. In this study, we propose a centralized, range- and anchor-based, hybrid algorithm called RH+ that aims to combine the powerful features of two orthogonal techniques: Classical Multi-Dimensional Scaling (CMDS) and Particle Spring Optimization (PSO). As a result, we find that our hybrid approach gives a fast-converging solution which is resilient to range-errors and very robust to topology changes. Across all topologies we studied, the average estimation error is less than 0.5m. when the average node density is 10 and only 2.5% of the nodes are beacons.

  6. Hybrid Multicast Transmission for Public Safety Network in 5G

    Directory of Open Access Journals (Sweden)

    Fei Qi

    2016-01-01

    Full Text Available We investigate the application of wireless multicast technology in public safety network (PSN in future wireless communication system. The hybrid unicast/multicast transmission system is proposed and analyzed in 3D massive multi-input multioutput (MIMO channel. The mutual coupling channel model is adopted under the different antenna array configuration scenarios. The proposed hybrid system adopts multicast beamforming in the multicast groups as well as multiuser-MIMO (MU-MIMO linear precoding in the unicast group to increase system throughput. The null space method based interference cancellation is further performed between each group to eliminate signal leakage generated from each group. Comparisons between two types of antenna array configurations, different channel models, linear precoding as well as multicast beamforming, and user grouping strategies for multicast services are presented and analyzed by simulation.

  7. Strategies for Service Composition in P2P Networks

    Science.gov (United States)

    Gerke, Jan; Reichl, Peter; Stiller, Burkhard

    Recently, the advance of service-oriented architectures and peer-to-peer networks has lead to the creation of service-oriented peer-to-peer networks, which enable a distributed and decentralized services market. Apart from the usage of single services, this market supports the merging of services into new services, a process called service composition. However, it is argued that for the time being this process can only be carried out by specialized peers, called service composers. This paper describes the new market created by these service composers, and models mathematically building blocks required for such a service composition. A general algorithm for service composition developed can be used independently of solutions for semantic difficulties and interface adaption problems of service composition. In a scenario for buying a distributed computing service, simulated strategies are evaluated according to their scalability and the market welfare they create.

  8. A hybrid neural network model for noisy data regression.

    Science.gov (United States)

    Lee, Eric W M; Lim, Chee Peng; Yuen, Richard K K; Lo, S M

    2004-04-01

    A hybrid neural network model, based on the fusion of fuzzy adaptive resonance theory (FA ART) and the general regression neural network (GRNN), is proposed in this paper. Both FA and the GRNN are incremental learning systems and are very fast in network training. The proposed hybrid model, denoted as GRNNFA, is able to retain these advantages and, at the same time, to reduce the computational requirements in calculating and storing information of the kernels. A clustering version of the GRNN is designed with data compression by FA for noise removal. An adaptive gradient-based kernel width optimization algorithm has also been devised. Convergence of the gradient descent algorithm can be accelerated by the geometric incremental growth of the updating factor. A series of experiments with four benchmark datasets have been conducted to assess and compare effectiveness of GRNNFA with other approaches. The GRNNFA model is also employed in a novel application task for predicting the evacuation time of patrons at typical karaoke centers in Hong Kong in the event of fire. The results positively demonstrate the applicability of GRNNFA in noisy data regression problems.

  9. Robot Positioning and Navigation Based on Hybrid Wireless Sensor Network

    Institute of Scientific and Technical Information of China (English)

    Shun-cai YAO; Jin-dong TAN; Hong-xia PAN

    2010-01-01

    Traditional sensor network and robot navigation are based an the map of detecting the fields available in advance.The optimal algorithms are developed to solve the energy saving,the shortest path problems,etc.However,in the practical encironment,there are many fields,whose map is difficult to get,and needs to be detected.In this paper a kind of ad-hoc navigation algorithm is explored,which is based on the hybrid sensor network without the prior map in advance.The navigation system is composed of static nodes and dynamic nodes.The static nodes monitor the occurrances of the events and broadcast them.In the system,a kind of algorithm is to locate the robot,which is based on cluster broadcasting.The dynamic nodes detect the adversary or dangerous fields and broadcast warning messages.The robot gets the message and follows ad-hoc routine to arrive where the events occur.In the whole process,energy saving has been taken into account.The algorithms,which are based on the hybrid sensor network,are given in this paper.The simulation and practical results are also available.

  10. Reduction of electromagnetic exposure using hybrid (DVB-H/UMTS) networks

    Science.gov (United States)

    Schack, M.; Unger, P.; Kürner, T.

    2007-06-01

    The hybrid mobile communication network described in this paper consists of a point-to-point network (UMTS) and a point-to-multipoint network (DVB-H). Using an additional DVB-H network increases the downlink capacity of the communications system. Another benefit of combining these two networks is an optimised transfer of data by collecting several user requests for a single response via the broadcast network DVB-H. It is analysed how the hybrid network structure influences the electromagnetic exposure. Therefore, realistic scenarios have been developed consisting of different user behaviour and different network structures. These scenarios provide building data for investigations of indoor coverage and realistic propagation of signals. In order to evaluate the grade of exposure, criteria have been defined. These criteria have been used for comparing a hybrid network with a single UMTS network in terms of electromagnetic exposure. The simulation results of the scenarios are shown for different network structures and network configurations.

  11. Improving resource utilization in hierarchy network by optimizing topological structure

    Science.gov (United States)

    Liu, G. L.; Peng, H. P.; Li, L. X.; Sun, F.; Yang, Y. X.

    2012-02-01

    We study the performance of peer-to-peer (P2P) network built on the top of hierarchy topological structure of local area networks (LAN). We find that the topological structure of the underlying physical network has significant impacts on the resource utilization of the P2P overlay network. The larger size of the physical network is, the lower resource utilization of the overlay network is. Through optimizing the topological structure of physical network, we propose two novel schemes to improve the resource utilization. The experimental results show that in any case the resource utilization of P2P network can always achieve 100% by these two schemes.

  12. Naming Game on Networks: Let Everyone be Both Speaker and Hearer

    Science.gov (United States)

    Gao, Yuan; Chen, Guanrong; Chan, Rosa H. M.

    2014-08-01

    To investigate how consensus is reached on a large self-organized peer-to-peer network, we extended the naming game model commonly used in language and communication to Naming Game in Groups (NGG). Differing from other existing naming game models, in NGG everyone in the population (network) can be both speaker and hearer simultaneously, which resembles in a closer manner to real-life scenarios. Moreover, NGG allows the transmission (communication) of multiple words (opinions) for multiple intra-group consensuses. The communications among indirectly-connected nodes are also enabled in NGG. We simulated and analyzed the consensus process in some typical network topologies, including random-graph networks, small-world networks and scale-free networks, to better understand how global convergence (consensus) could be reached on one common word. The results are interpreted on group negotiation of a peer-to-peer network, which shows that global consensus in the population can be reached more rapidly when more opinions are permitted within each group or when the negotiating groups in the population are larger in size. The novel features and properties introduced by our model have demonstrated its applicability in better investigating general consensus problems on peer-to-peer networks.

  13. Hybrid multiobjective evolutionary design for artificial neural networks.

    Science.gov (United States)

    Goh, Chi-Keong; Teoh, Eu-Jin; Tan, Kay Chen

    2008-09-01

    Evolutionary algorithms are a class of stochastic search methods that attempts to emulate the biological process of evolution, incorporating concepts of selection, reproduction, and mutation. In recent years, there has been an increase in the use of evolutionary approaches in the training of artificial neural networks (ANNs). While evolutionary techniques for neural networks have shown to provide superior performance over conventional training approaches, the simultaneous optimization of network performance and architecture will almost always result in a slow training process due to the added algorithmic complexity. In this paper, we present a geometrical measure based on the singular value decomposition (SVD) to estimate the necessary number of neurons to be used in training a single-hidden-layer feedforward neural network (SLFN). In addition, we develop a new hybrid multiobjective evolutionary approach that includes the features of a variable length representation that allow for easy adaptation of neural networks structures, an architectural recombination procedure based on the geometrical measure that adapts the number of necessary hidden neurons and facilitates the exchange of neuronal information between candidate designs, and a microhybrid genetic algorithm ( microHGA) with an adaptive local search intensity scheme for local fine-tuning. In addition, the performances of well-known algorithms as well as the effectiveness and contributions of the proposed approach are analyzed and validated through a variety of data set types.

  14. ARTIFICIAL NEURAL NETWORKS BASED GEARS MATERIAL SELECTION HYBRID INTELLIGENT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    X.C. Li; W.X. Zhu; G. Chen; D.S. Mei; J. Zhang; K.M. Chen

    2003-01-01

    An artificial neural networks(ANNs) based gear material selection hybrid intelligent system is established by analyzing the individual advantages and weakness of expert system (ES) and ANNs and the applications in material select of them. The system mainly consists of tow parts: ES and ANNs. By being trained with much data samples,the back propagation (BP) ANN gets the knowledge of gear materials selection, and is able to inference according to user input. The system realizes the complementing of ANNs and ES. Using this system, engineers without materials selection experience can conveniently deal with gear materials selection.

  15. A Neural Networks-Based Hybrid Routing Protocol for Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Nenad Kojić

    2012-06-01

    Full Text Available The networking infrastructure of wireless mesh networks (WMNs is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic—i.e., neural networks (NNs. This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission. The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance.

  16. A Neural Networks-Based Hybrid Routing Protocol for Wireless Mesh Networks

    Science.gov (United States)

    Kojić, Nenad; Reljin, Irini; Reljin, Branimir

    2012-01-01

    The networking infrastructure of wireless mesh networks (WMNs) is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic—i.e., neural networks (NNs). This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission). The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance. PMID:22969360

  17. A neural networks-based hybrid routing protocol for wireless mesh networks.

    Science.gov (United States)

    Kojić, Nenad; Reljin, Irini; Reljin, Branimir

    2012-01-01

    The networking infrastructure of wireless mesh networks (WMNs) is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic-i.e., neural networks (NNs). This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission). The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance.

  18. P2P Networks with IP Based Communication

    OpenAIRE

    Anupriya Koneru; Krishna Prasad MHM

    2012-01-01

    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...

  19. Modeling Integrated Cellular Machinery Using Hybrid Petri-Boolean Networks

    Science.gov (United States)

    Berestovsky, Natalie; Zhou, Wanding; Nagrath, Deepak; Nakhleh, Luay

    2013-01-01

    The behavior and phenotypic changes of cells are governed by a cellular circuitry that represents a set of biochemical reactions. Based on biological functions, this circuitry is divided into three types of networks, each encoding for a major biological process: signal transduction, transcription regulation, and metabolism. This division has generally enabled taming computational complexity dealing with the entire system, allowed for using modeling techniques that are specific to each of the components, and achieved separation of the different time scales at which reactions in each of the three networks occur. Nonetheless, with this division comes loss of information and power needed to elucidate certain cellular phenomena. Within the cell, these three types of networks work in tandem, and each produces signals and/or substances that are used by the others to process information and operate normally. Therefore, computational techniques for modeling integrated cellular machinery are needed. In this work, we propose an integrated hybrid model (IHM) that combines Petri nets and Boolean networks to model integrated cellular networks. Coupled with a stochastic simulation mechanism, the model simulates the dynamics of the integrated network, and can be perturbed to generate testable hypotheses. Our model is qualitative and is mostly built upon knowledge from the literature and requires fine-tuning of very few parameters. We validated our model on two systems: the transcriptional regulation of glucose metabolism in human cells, and cellular osmoregulation in S. cerevisiae. The model produced results that are in very good agreement with experimental data, and produces valid hypotheses. The abstract nature of our model and the ease of its construction makes it a very good candidate for modeling integrated networks from qualitative data. The results it produces can guide the practitioner to zoom into components and interconnections and investigate them using such more

  20. Modeling integrated cellular machinery using hybrid Petri-Boolean networks.

    Directory of Open Access Journals (Sweden)

    Natalie Berestovsky

    Full Text Available The behavior and phenotypic changes of cells are governed by a cellular circuitry that represents a set of biochemical reactions. Based on biological functions, this circuitry is divided into three types of networks, each encoding for a major biological process: signal transduction, transcription regulation, and metabolism. This division has generally enabled taming computational complexity dealing with the entire system, allowed for using modeling techniques that are specific to each of the components, and achieved separation of the different time scales at which reactions in each of the three networks occur. Nonetheless, with this division comes loss of information and power needed to elucidate certain cellular phenomena. Within the cell, these three types of networks work in tandem, and each produces signals and/or substances that are used by the others to process information and operate normally. Therefore, computational techniques for modeling integrated cellular machinery are needed. In this work, we propose an integrated hybrid model (IHM that combines Petri nets and Boolean networks to model integrated cellular networks. Coupled with a stochastic simulation mechanism, the model simulates the dynamics of the integrated network, and can be perturbed to generate testable hypotheses. Our model is qualitative and is mostly built upon knowledge from the literature and requires fine-tuning of very few parameters. We validated our model on two systems: the transcriptional regulation of glucose metabolism in human cells, and cellular osmoregulation in S. cerevisiae. The model produced results that are in very good agreement with experimental data, and produces valid hypotheses. The abstract nature of our model and the ease of its construction makes it a very good candidate for modeling integrated networks from qualitative data. The results it produces can guide the practitioner to zoom into components and interconnections and investigate them

  1. Modeling integrated cellular machinery using hybrid Petri-Boolean networks.

    Directory of Open Access Journals (Sweden)

    Natalie Berestovsky

    Full Text Available The behavior and phenotypic changes of cells are governed by a cellular circuitry that represents a set of biochemical reactions. Based on biological functions, this circuitry is divided into three types of networks, each encoding for a major biological process: signal transduction, transcription regulation, and metabolism. This division has generally enabled taming computational complexity dealing with the entire system, allowed for using modeling techniques that are specific to each of the components, and achieved separation of the different time scales at which reactions in each of the three networks occur. Nonetheless, with this division comes loss of information and power needed to elucidate certain cellular phenomena. Within the cell, these three types of networks work in tandem, and each produces signals and/or substances that are used by the others to process information and operate normally. Therefore, computational techniques for modeling integrated cellular machinery are needed. In this work, we propose an integrated hybrid model (IHM that combines Petri nets and Boolean networks to model integrated cellular networks. Coupled with a stochastic simulation mechanism, the model simulates the dynamics of the integrated network, and can be perturbed to generate testable hypotheses. Our model is qualitative and is mostly built upon knowledge from the literature and requires fine-tuning of very few parameters. We validated our model on two systems: the transcriptional regulation of glucose metabolism in human cells, and cellular osmoregulation in S. cerevisiae. The model produced results that are in very good agreement with experimental data, and produces valid hypotheses. The abstract nature of our model and the ease of its construction makes it a very good candidate for modeling integrated networks from qualitative data. The results it produces can guide the practitioner to zoom into components and interconnections and investigate them

  2. Networked Operations of Hybrid Radio Optical Communications Satellites

    Science.gov (United States)

    Hylton, Alan; Raible, Daniel

    2014-01-01

    In order to address the increasing communications needs of modern equipment in space, and to address the increasing number of objects in space, NASA is demonstrating the potential capability of optical communications for both deep space and near-Earth applications. The Integrated Radio Optical Communications (iROC) is a hybrid communications system that capitalizes on the best of both the optical and RF domains while using each technology to compensate for the other's shortcomings. Specifically, the data rates of the optical links can be higher than their RF counterparts, whereas the RF links have greater link availability. The focus of this paper is twofold: to consider the operations of one or more iROC nodes from a networking point of view, and to suggest specific areas of research to further the field. We consider the utility of Disruption Tolerant Networking (DTN) and the Virtual Mission Operation Center (VMOC) model.

  3. ANOMALY DETECTION IN NETWORKING USING HYBRID ARTIFICIAL IMMUNE ALGORITHM

    Directory of Open Access Journals (Sweden)

    D. Amutha Guka

    2012-01-01

    Full Text Available Especially in today’s network scenario, when computers are interconnected through internet, security of an information system is very important issue. Because no system can be absolutely secure, the timely and accurate detection of anomalies is necessary. The main aim of this research paper is to improve the anomaly detection by using Hybrid Artificial Immune Algorithm (HAIA which is based on Artificial Immune Systems (AIS and Genetic Algorithm (GA. In this research work, HAIA approach is used to develop Network Anomaly Detection System (NADS. The detector set is generated by using GA and the anomalies are identified using Negative Selection Algorithm (NSA which is based on AIS. The HAIA algorithm is tested with KDD Cup 99 benchmark dataset. The detection rate is used to measure the effectiveness of the NADS. The results and consistency of the HAIA are compared with earlier approaches and the results are presented. The proposed algorithm gives best results when compared to the earlier approaches.

  4. Secure Mobile Agent for Telemedicine Based on P2P Networks

    OpenAIRE

    Hsu, Wen-Shin; Pan, Jiann-I

    2013-01-01

    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...

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

    OpenAIRE

    Hall, Cyrus; Carzaniga, Antonio

    2011-01-01

    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...

  6. 面向系统吞吐率最大化的P2P自适应覆盖网络%Adaptive Peer-to-Peer Overlay for the Maximum Throughput

    Institute of Scientific and Technical Information of China (English)

    冯国富; 张金城; 韩冰青; 孙玉星; 李文中

    2012-01-01

    The intrinsic value of P2P system is to improve the utility ratio of system resources and the system throughput,as well as to satisfy more data requests. In many unstructured P2P systems, the peers with high popularity weight in the overlay are assigned with more connections,so as to receive more messages and hit more requests and finally to improve the search success rate. Due to the lack consideration of bandwidth, the peers with high weight are apt to be o-verloaded and the available services decrease. Therefore,the high success rate alone doesn't mean the high throughput and service availability. An optimization solution of overlay network was proposed in this paper to improve the throughput and the number of access customers, in which the connections are adaptively adjusted according to the available bandwidth and the popularity weight. Our simulations show that our method can improve the system throughput as high as 22% with low cost.%P2P系统的本质任务在于提高资源利用率和系统吞吐量,满足更多用户的数据请求.在无结构P2P中,通常分配高权重节点以较多连接,使之收到并命中更多查询,以提高搜索成功率.但高搜索成功率本身却未必能够提高系统吞吐量,因为受带宽因素影响,高权重节点的负载较重,造成服务可用性降低.提出了一种覆盖网络优化方案,即根据带宽负载和存储权重自适应性调整节点连接度,优化覆盖网络结构,提高系统吞吐量.模拟实验数据表明,基于带宽和搜索成功率的覆盖网络优化方案可以以很小代价提高系统吞吐量,当文件体积较小时提高比例可高达22%.

  7. Hybrid Architecture IPTV System Scheme%混合架构IPTV系统方案

    Institute of Scientific and Technical Information of China (English)

    于宏锦; 甘露; 刘新; 叶德建

    2011-01-01

    传统内容分发网络(CDN)互联协议电视(IPTV)系统的部署和维护成本较高.为此,提出采用CDN和对等(P2P)混合架构的IPTV系统方案.在原有系统基础上,加入P2P技术,对上海电信IPTV系统的实验数据加以分析,设计节目热门度模型.实验结果表明,该方案能降低系统开销,提高系统的可扩展性,使用该热门度模型后,降低约40%的系统负载.%Aiming at the problem that traditional Content Delivery Network(CDN) architecture Internet Protocol Television(IPTV) system is expensive to deploy and maintain. Hybrid architecture IPTV system project is proposed. The original IPTV system of CDN architecture is merged with Peer-to-Peer(P2P). This paper analyzes the real data of shanghai telecom IPTV system, designs an approximate model of program popular degree. Experimental results show that, this scheme can cut costs and enhance the scalability, the model of popular degree get about 40% system load reducement as a result.

  8. Collaborative Multi-Layer Network Coding For Hybrid Cellular Cognitive Radio Networks

    KAUST Repository

    Moubayed, Abdallah J.

    2014-05-01

    In this thesis, as an extension to [1], we propose a prioritized multi-layer network coding scheme for collaborative packet recovery in hybrid (interweave and underlay) cellular cognitive radio networks. This scheme allows the uncoordinated collaboration between the collocated primary and cognitive radio base-stations in order to minimize their own as well as each other’s packet recovery overheads, thus by improving their throughput. The proposed scheme ensures that each network’s performance is not degraded by its help to the other network. Moreover, it guarantees that the primary network’s interference threshold is not violated in the same and adjacent cells. Yet, the scheme allows the reduction of the recovery overhead in the collocated primary and cognitive radio networks. The reduction in the cognitive radio network is further amplified due to the perfect detection of spectrum holes which allows the cognitive radio base station to transmit at higher power without fear of violating the interference threshold of the primary network. For the secondary network, simulation results show reductions of 20% and 34% in the packet recovery overhead, compared to the non-collaborative scheme, for low and high probabilities of primary packet arrivals, respectively. For the primary network, this reduction was found to be 12%. Furthermore, with the use of fractional cooperation, the average recovery overhead is further reduced by around 5% for the primary network and around 10% for the secondary network when a high fractional cooperation probability is used.

  9. A Hybrid Structure for Data Aggregation in Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Hedieh Sajedi

    2014-01-01

    Full Text Available In recent years, wireless sensor networks have been used for various applications such as environmental monitoring, military and medical applications. A wireless sensor network uses a large number of sensor nodes that continuously collect and send data from a specific region to a base station. Data from sensors are collected from the study area in the common scenario of sensor networks. Afterward, sensed data is sent to the base station. However, neighboring sensors often lead to redundancy of data. Transmission of redundant data to the base station consumes energy and produces traffic, because process is run in a large network. Data aggregation was proposed in order to reduce redundancy in data transformation and traffic. The most popular communication protocol in this field is cluster based data aggregation. Clustering causes energy balance, but sometimes energy consumption is not efficient due to the long distance between cluster heads and base station. In another communication protocol, which is based on a tree construction, because of the short distance between the sensors, energy consumption is low. In this data aggregation approach, since each sensor node is considered as one of the vertices of a tree, the depth of tree is usually high. In this paper, an efficient hierarchical hybrid approach for data aggregation is presented. It reduces energy consumption based on clustering and minimum spanning tree. The benefit of combining clustering and tree structure is reducing the disadvantages of previous structures. The proposed method firstly employs clustering algorithm and then a minimum spanning tree is constructed based on cluster heads. Our proposed method was compared to LEACH which is a well-known data aggregation method in terms of energy consumption and the amount of energy remaining in each sensor network lifetime. Simulation results indicate that our proposed method is more efficient than LEACH algorithm considering energy

  10. Training and Peer-to-Peer Learning (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2013-04-01

    The Clean Energy Solutions Center helps governments, advisors, and analysts create policies and programs that advance the deployment of clean energy technologies. The Solutions Center is an initiative of the Clean Energy Ministerial (CEM), a global forum to share best practices and promote policies and programs that encourage and facilitate the transition to a global clean energy economy, and UN-Energy, the United Nations' interagency mechanism to scale-up global clean energy use.

  11. Tracking Using Peer-to-Peer Smart Infrared Cameras

    Science.gov (United States)

    2008-11-05

    calibration and gesture recognition from multi-spectral camera setups, including infrared and visible cameras. Result: We developed new object models for...work on single-camera gesture recognition . We partnered with Yokogawa Electric to develop new architectures for embedded computer vision. We developed

  12. Millennials, Peer-to-Peer Accommodation and the Hotel Industry

    Directory of Open Access Journals (Sweden)

    Alma Pentescu

    2016-01-01

    The aim of this paper is to present these challenges for the hotel industry, because there has notbeen significant research concerning the trends and changes this new generation / new businessmodel will bring to the hospitality industry. Finally, it suggests how hoteliers could adapt to thesenew expectations and proposes several questions for future research.

  13. Peer-to-Peer Learning and the Army Learning Model

    Science.gov (United States)

    2012-06-08

    electronic books , augmented reality, gesture-based computing, and visual data analysis will have the greatest effect on the learning environment in...open content, electronic books , augmented reality, gesture based computing, and visual data analysis,” are some of the needs for change (Department of

  14. Semantic Routing in Peer-to-Peer Systems

    NARCIS (Netherlands)

    Siebes, R.M.

    2006-01-01

    Currently search engines like Google, Yahoo and Excite are centralized, which means that all queries that users post are sent to some big servers (or server group) that handle them. In this way it is easy for the systems to relate IP-addresses with the queries posted from them. Clearly privacy is

  15. Robust Reputations for Peer-to-peer Markets

    Science.gov (United States)

    2007-05-24

    relative strengths and weaknesses. Furthermore, such a platform should improve researcher productivity, since it will no longer be necessary to develop a...vendors unite to voice their concerns,” Startup Journal, May 2004, http://startup.wsj.com/ ecommerce / ecommerce /20040526-wingfield.html. 179 [117] B. Yu and M

  16. Inflammablog: peer-to-peer online learning in immunology.

    Science.gov (United States)

    Cohen, Zoë; Cohen, J John

    2013-03-01

    Is it possible for students in different courses, at different academic levels, and at different universities to learn immunology together using the Internet? We teach a colloquium on inflammation for undergraduates at the University of Arizona and a lecture course on human immunology for graduate students and clinical and basic science fellows at the University of Colorado Anschutz Medical Campus. Students in these programs, being scattered about large campuses, have little time for student-directed discussion and peer interactions, and they never have the opportunity to meet students in the course in the other state. Instead of requiring the usual essays and term papers, we set up a blog (an online discussion group) for the two courses, and required all students to post, and comment on other posts, within and between the courses. Student writing is normally directed at a single reader, the instructor, which seems like a waste of talent; we encouraged peer exchanges. Furthermore, we were interested in observing the interactions between the Colorado students, who were older and sometimes experienced professionals, and the younger Arizonans. We used a blog because it is administratively impossible to enroll the students in two universities in a single courseware (learning management system) site. Blogging has offered insights into students' comfort with this form of social medium, and into the potential for this approach in light of the rapid adoption of blended and massively open online courses.

  17. A Peer-to-Peer Indexing Service for Data Grids

    DEFF Research Database (Denmark)

    Jensen, Henrik Thostrup; Kleist, Josva

    2007-01-01

    We present an index system for locating files or other data objects in a grid environment. The system is constructed using a distributed hash table, and is scalable, fault-tolerant, and self-organizing. The index is dynamically updated to reflect the state of the storage elements, and can hence...

  18. Art-mediated peer-to-peer learning of empathy.

    Science.gov (United States)

    Potash, Jordan; Chen, Julie

    2014-08-01

    Making experiential art in a clinical clerkship offers opportunities for students to gain self-awareness and enhance their empathic understanding of patients. The student-created art can be further used as teaching material for other students. The graduating class of 2012 from Ajou University School of Medicine in South Korea was interested in learning about medical humanities initiatives at the Li Ka Shing Faculty of Medicine, University of Hong Kong (HKU), and made an educational visit in May 2012. As part of the core family medicine curriculum, third-year HKU medical students created poetry and art based on their experiences witnessing patients in pain and suffering. Twenty of the artworks and accompanying reflective writing were chosen for an exhibition. The visiting students viewed the exhibit and created their own art based on their emotional response to one piece selected from the exhibit. The combination of viewing art made by their peers and creating art in response resulted in empathic understanding of patient pain and suffering, and an appreciation of holistic care and the value of the doctor-patient relationship. Medical student-generated artwork has the potential to educate both students and professionals on humanistic aspects of medical care. © 2014 John Wiley & Sons Ltd.

  19. Fatigue Assessment: Subjective Peer-to-Peer Fatigue Scoring (Reprint)

    Science.gov (United States)

    2013-10-01

    validity. However, it is diffi cult to translate many highly specifi c laboratory-based neurocognitive or psychomotor experimental tests into a...sense of each other ’ s “ baseline. ” Scor - ing is then predicated upon the recognition of a signifi - cant deviation from this baseline. This may...screening tests are de- signed to be sensitive but not necessarily specifi c, elevated scores prompt further attention and investigation. Fur- thering

  20. Empowering First Responders - Peer-to-Peer Technology

    Science.gov (United States)

    2004-04-01

    bandwidth by allocating former commercial TV frequencies to them, most agencies project using up this new bandwidth almost immediately upon its...modem is a modem designed to operate over cable TV lines. Because the coaxial cable used by cable TV provides much greater bandwidth than telephone...org/c3is/ccbm/mic.html. 14 Discussions with Special Agent Perla Garcia-Alcocer with the Mexican Instituto Nacional Para el Combate a las Drogas