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We consider a publisher that earns advertising revenue while providing content to serve a heterogeneous population of consumers. The consumers derive benefit from consuming content but suffer from delivery delays. [...]

Civil engineers have introduced sophisticated sensing and control systems to better operate infrastructure systems, resulting in what are termed advanced infrastructure systems (AISs). Past AIS research has largely focused upon the sensors needed to collect data, as well as applications using this data to derive information to drive management/control decisions. Of equal importance to AIS success is the availability of an effective data delivery mechanism to ensure that data are effectively provided to applications. This research examined the challenge of data delivery in AISs. Following an analysis of AIS characteristics and a review of the state-of-the-practice in AIS data delivery, the paper presents a peer-to-peer-based publish/subscribe architecture developed by the research team to meet AIS data delivery requirements. Finally, a case study is presented in which the architecture is tailored for a vehicle-infrastructure integration AIS implementation. Simulation results of the implementation reveal that the proposed architecture provides significant scalability benefits, as compared to traditional data delivery approaches, providing up to a 50% reduction in message transmissions without increasing delivery times to unacceptable levels. CE Database subject headings: Data communication; Data collection; Integrated systems; Intelligent transportation systems; Project delivery; Infrastructure. Author keywords: Infrastructure; Information technology; Data communication; Integrated systems; Intelligent transportation systems. DOI: 10.1061/(ASCE)0887-3801(2010)24:1(65)

The peer-to-peer (P2P) paradigm has become very popular for storing and sharing information in a totally decentralized manner. At first, research focused on P2P systems that host 1 D data. Nowadays, the need for P2P applications with multidimensional data has emerged, motivating research on P2P systems that manage such data. The majority of the proposed techniques are based either on the distribution of centralized indexes or on the reduction of multidimensional data to one dimension. Our goal is to create from scratch a technique that is inherently distributed and also maintains the multidimensionality of data. Our focus is on structured P2P systems that share spatial information. We present SPATIALP2P, a totally decentralized indexing and searching framework that is suitable for spatial data. SPATIALP2P supports P2P applications in which spatial information of various sizes can be dynamically inserted or deleted, and peers can join or leave. The proposed technique preserves well locality and directionality of space. Index Terms--Peer-to-peer, structured overlays, distributed hash tables, spatial data.

The control message overhead created by the distributed hash table (DHT)-based peer-to-peer Chord protocol is evaluated under different churn rates and for different networking sizes. The DHT-based P2P structure can be stabilized by adjusting the update period. Message overhead for the Chord architecture is moderate under high churn rates and Internet-wide networking.

The implementation of a peer-assisted content distribution network results in capacity savings and performance gains compared to pure client/server systems. This hybrid approach boosts network performance and reliability compared to pure peer-to-peer networks.

The use of hybrid peer-to-peer (P2P) technology results in enhanced video streaming due to the technology's capacity advantage, which translates into higher bit rates. Hybrid P2P approaches can serve as a cost-effective video streaming platform due to its high bit rates, latency quality, and deployment flexibility for future digital media models.

A framework for providing quality of service (QoS) requirements over advanced switching (AS) is presented. The performance of the proposals is evaluated in a multimedia scenario using standard traffic types.

The ATLAS Event Monitoring service (Emon) is a CORBA-based [1] peer-to-peer data distribution framework, which has been implemented for ATLAS--one of CERN's forthcoming particle physics experiments. Its purpose is to sample collision event data from various stages of the data flow chain and efficiently distribute them to the users. This paper discusses various technical details of the current peer-to-peer-based implementation. A special focus lies on dependability and the provision of scalability and predictable performance. A comparative study of message complexity and scalability as well as practical test results obtained during the HLT/DAQ Large Scale and Performance Test periods in July 2005 and November 2006 will be presented. Apart from that, a recent addition that facilitates the parallel analysis of event data on a set of machines will be presented. Index Terms--ATLAS, data acquisition, high-energy physics, LHC, monitoring, peer-to-peer.

The inner product measures how closely two feature vectors are related. It is an important primitive for many popular data mining tasks, for example, clustering, classification, correlation computation, and decision tree construction. If the entire data set is available at a single site, then computing the inner product matrix and identifying the top (in terms of magnitude) entries is trivial. However, in many real-world scenarios, data is distributed across many locations and transmitting the data to a central server would be quite communication intensive and not scalable. This paper presents an approximate local algorithm for identifying top-l inner products among pairs of feature vectors in a large asynchronous distributed environment such as a peer-to-peer (P2P) network. We develop a probabilistic algorithm for this purpose using order statistics and the Hoeffding bound. We present experimental results to show the effectiveness and scalability of the algorithm. Finally, we demonstrate an application of this technique for interest-based community formation in a P2P environment. Index Terms--Distributed data mining, inner product, peer-to-peer network.

A Differentiated Search (DiffSearch) algorithm is suggested using query answering heterogeneity to enhance the search efficiency of unstructured peer-to-peer (P2P) networks by providing higher querying priority to peers with high querying reply capabilities. The trace analysis and simulation demonstrates that DiffSearch saves upto 60% search traffic and enhances the search efficiency without restoring index operations.

Abstract A variety of digital realia available on Peer-to-Peer networks (P2P), such as Emule, KaZaa and Bittorrent, can enhance the learning process for students of foreign language and culture, and [...]

The Knowledge Grid needs to operate with a scalable platform to provide large-scale intelligent services. A key function of such a platform is to efficiently support various complex queries in a dynamic large-scale network environment. This paper proposes a platform to support index-based path queries by incorporating a semantic overlay with an underlying structured P2P network that provides object location and management services. Various distributed indexing structures can be dynamically formed by publishing semantic objects as indexing nodes. Queries are forwarded along the chains of semantic object pointers to search for objects. We investigate the deployment of a scalable distributed trie index for broadcast queries on key strings, propose a decentralized load balancing method for solving the problem of uneven load distribution incurred by heterogeneity of loads and node capacities and by the distributed trie index, and give an approach for improving the availability of the semantic overlay and its trie index. Experiments demonstrate the scalability of the proposed platform. Index Terms--Peer-to-peer, semantic overlay, knowledge grid, path query, distributed trie index, load balancing, replication.

Abstract: Load balancing is a generally concerned problem in peer-to-peer (P2P) systems. Many researches on load balancing in the structured P2P systems have been launched currently, such as Chord or [...]

This paper discusses a framework in which catalog service communities are built, linked for interaction, and constantly monitored and adapted over time. A catalog service community (represented as a peer node in a peer-to-peer network) in our system can be viewed as domain specific data integration mediators representing the domain knowledge and the registry information. The query routing among communities is performed to identify a set of data sources that are relevant to answering a given query. The system monitors the interactions between the communities to discover patterns that may lead to restructuring of the network (e.g., irrelevant peers removed, new relationships created, etc.). Index Terms--Catalog portals, e-catalogs, peer-to-peer (P2P), self-adaptivity.

Desktop grids have been used to perform some of the largest computations in the world and have the potential to grow by several more orders of magnitude. However, current approaches to utilizing desktop resources require either centralized servers or extensive knowledge of the underlying system, limiting their scalability. We propose a new design for desktop grids that relies on a self-organizing, fully decentralized approach to the organization of the computation. Our approach, called the organic grid, is a radical departure from current approaches and is modeled after the way complex biological systems organize themselves. Similar to current desktop grids, a large computational task is broken down into sufficiently small subtasks. Each subtask is encapsulated into a mobile agent, which is then released on the grid and discovers computational resources using autonomous behavior. In the process of "colonization" of available resources, the judicious design of the agent behavior produces the emergence of crucial properties of the computation that can be tailored to specific classes of applications. We demonstrate this concept with a reduced-scale proof-of-concept implementation that executes a data-intensive independent-task application on a set of heterogeneous, geographically distributed machines. We present a detailed exploration of the design space of our system and a performance evaluation of our implementation using metrics appropriate for assessing self-organizing desktop grids. Index Terms--Grid scheduling, mobile agents, self-organizing computation.

Peer-to-peer search networks are a popular and widely deployed means of searching massively distributed digital information repositories. Unfortunately, as such networks grow, peers may become overloaded processing messages from other peers. This article examines how to reduce the load on nodes in P2P networks by allowing them to self-organize into a relatively efficient network, and then self-tune to make the network even more efficient. Two local operations used by a peer are introduced: connect(), in which the peer forms an ad hoc search or index link to another peer, and break(), in which the peer breaks a link that is producing too much load. By replacing fixed rules with dynamic local decision-making, such "self-supervising" networks can better adjust to network conditions. Different ways to implement connect() and break() are described, and the network structures that form under different configurations are examined. Simulation results indicate that the ad hoc networks formed using the described techniques are more efficient than popular supernode topologies for several important scenarios. Results for the fault tolerance and search latency of such ad hoc networks are also presented. Categories and Subject Descriptors: H.3.4 [Information Storage and Retrieva]: Systems and Software--Distributed systems; information networks; performance evaluation (efficiency and effectiveness); H.3.3 [Information Storage and Retrieval]: Information Search and Retrieval--Search process; C.2.4 [Computer-Communication Networks]: Distributed Systems--Distributed databases; distributed applications General Terms: Design, Performance, Reliability Additional Key Words and Phrases: Peer-to-peer systems, information search and discovery

Protocols are proposed to achieve mutual anonymity in a peer to peer (P2P) file-sharing environment.

Peer-to-peer information sharing environments are increasingly gaining acceptance on the Internet as they provide an infrastructure in which the desired information can be located and downloaded while preserving the anonymity of both requestors and providers. As recent experience with P2P environments such as Gnutella shows, anonymity opens the door to possible misuses and abuses by resource providers exploiting the network as a way to spread tampered-with resources, including malicious programs, such as Trojan Horses and viruses. In this paper, we propose an approach to P2P security where servents can keep track, and share with others, information about the reputation of their peers. Reputation sharing is based on a distributed polling algorithm by which resource requestors can assess the reliability of perspective providers before initiating the download. The approach complements existing P2P protocols and has a limited impact on current implementations. Furthermore, it keeps the current level of anonymity of requestors and providers, as well as that of the parties sharing their view on others' reputations. Index Terms--P2P network, reputation, credibility, polling protocol.