646 research outputs found
File management in a mobile DHT-based P2P environment
The emergence of mobile P2P systems is largely due to the evolution of mobile devices into powerful information processing units. The relatively structured context that results from the mapping of mobile patterns of behaviour onto P2P models is however constrained by the vulnerabilities of P2P networks and the inherent limitations of mobile devices. Whilst the implementation of P2P models gives rise to security and reliability issues, the deployment of mobile devices is subject to efficiency constraints. This paper presents the development and deployment of a mobile P2P system based on distributed hash tables (DHT). The secure, reliable and efficient dispersal of files is taken as an application. Reliability was addressed by providing two methods for file dispersal: replication and erasure coding. Security constraints were catered for by incorporating an authentication mechanism and three encryption schemes. Lightweight versions of various algorithms were selected in order to attend to efficiency requirements
CHORUS Deliverable 2.1: State of the Art on Multimedia Search Engines
Based on the information provided by European projects and national initiatives related to multimedia search as well as domains experts that participated in the CHORUS Think-thanks and workshops, this document reports on the state of the art related to multimedia content search from, a technical, and socio-economic perspective.
The technical perspective includes an up to date view on content based indexing and retrieval technologies, multimedia search in the context of mobile devices and peer-to-peer networks, and an overview of current evaluation and benchmark inititiatives to measure the performance of multimedia search engines.
From a socio-economic perspective we inventorize the impact and legal consequences of these technical advances and point out future directions of research
A NOVEL LINEAR DIOPHANTINE EQUATION-BAESD LOW DIAMETER STRUCTURED PEER-TO-PEER NETWORK
This research focuses on introducing a novel concept to design a scalable, hierarchical interest-based overlay Peer-to-Peer (P2P) system. We have used Linear Diophantine Equation (LDE) as the mathematical base to realize the architecture. Note that all existing structured approaches use Distributed Hash Tables (DHT) and Secure Hash Algorithm (SHA) to realize their architectures. Use of LDE in designing P2P architecture is a completely new idea; it does not exist in the literature to the best of our knowledge. We have shown how the proposed LDE-based architecture outperforms some of the most well established existing architecture. We have proposed multiple effective data query algorithms considering different circumstances, and their time complexities are bounded by (2+ r/2) only; r is the number of distinct resources. Our alternative lookup scheme needs only constant number of overlay hops and constant number of message exchanges that can outperform DHT-based P2P systems. Moreover, in our architecture, peers are able to possess multiple distinct resources. A convincing solution to handle the problem of churn has been offered. We have shown that our presented approach performs lookup queries efficiently and consistently even in presence of churn. In addition, we have shown that our design is resilient to fault tolerance in the event of peers crashing and leaving. Furthermore, we have proposed two algorithms to response to one of the principal requests of P2P applicationsâ users, which is to preserve the anonymity and security of the resource requester and the responder while providing the same light-weighted data lookup
SDDSfL vs. local disk - a comparative study for Linux
Efficient data management and distribution in a multicomputer is a subject of much research. Distributed file systems are the most common solution of this problem, however, recent works are focused on more general data distribution protocols. Scalable, Distributed Data Structures (SDDS) are another promising approach to this issue. In this paper we discuss the efficiency of an implementation of SDDS in various applications. The results of experiments are presented
Health technology assessment for digital health technologies
Health technology assessment (HTA) frameworks used for making public funding decisions on digital health technologies (DHTs) have not been informed by large stakeholder preference studies and rarely cover all nine domains of the widely used EUnetHTA âCore Modelâ. Our aim was to develop a literature-informed and stakeholder-prioritised checklist of DHT-specific considerations for DHTs that manage chronic disease that extends an internationally established HTA framework. We conducted two systematic reviews to identify: (i) DHT evaluation frameworks and (ii) primary research on DHTs published until 20 March 2020. Stakeholder prioritisation of issues was performed using a best-worst preference study among a broad cross-section of patients, carers, health professionals, and the general population in Australia, Canada, New Zealand, and the UK. Systematic review issues were prioritised and adapted for use as a practical checklist. DHT evaluation content was recommended by 44 identified frameworks for 28 of the 145 issues in the Core Model and for 22 new DHT-specific issues. A coverage assessment of 112 clinical studies of remote treatment and self-management DHTs for patients with cardiovascular disease or diabetes revealed that less than half covered DHT-specific content in all but one domain, or traditional HTA content in clinical effectiveness and ethical analysis. The preference survey of 1,251 stakeholders identified broad agreement on the 12 most important DHT attributes, six of which were related to safety. The most important attribute was âhelps health professionals respond quickly when changes in patient care are neededâ, which is not a focus of existing DHT HTA frameworks. Using the thesis-developed checklist in conjunction with the Core Model can enable users to perform a DHT-specific and comprehensive HTA on DHTs that manage chronic disease and can assist primary researchers to collect appropriate data to inform this HTA
Proof-of-Concept Application - Annual Report Year 1
In this document the Cat-COVITE Application for use in the CATNETS Project is introduced and motivated. Furthermore an introduction to the catallactic middleware and Web Services Agreement (WS-Agreement) concepts is given as a basis for the future work. Requirements for the application of Cat-COVITE with in catallactic systems are analysed. Finally the integration of the Cat-COVITE application and the catallactic middleware is described. --Grid Computing
A Secure and User Privacy-Preserving Searching Protocol for Peer-to-Peer Networks
File sharing peer-to-peer networks have become quite popular of late as a new paradigm for information exchange among large number of users in the Internet. However, these networks suffer from several problems such as fake content distribution, free riding, whitewashing, poor search scalability, lack of a robust trust model and absence of user privacy protection mechanism. In this paper, a secure and efficient searching scheme for peer-to-peer networks has been proposed that utilizes topology adaptation by constructing an overlay of trusted peers where the neighbors are selected based on their trust ratings and content similarities. While increasing the search efficiency by intelligently exploiting the formation of semantic community structures among the trustworthy peers, the scheme provides a highly reliable module for protecting the privacy of the users and data in the network. Simulation results have demonstrated that the proposed scheme provides efficient searching to good peers while penalizing the malicious peers by increasing their search times
Defining Routing Policies in Peer-to-Peer Overlay Networks
This masterâs thesis involves the definition and development of a policy-based routing scheme for peer-to-peer overlay networks. Many peer-to-peer networks are in existence today and each has various methods for discovering new peers, searching for content, and overcoming connectivity problems. The addition of efficient policy-based routing enhances the ability of peers within overlay networks to make appropriate routing decisions. Policy-based routing provides a means for peers to define the types of network traffic they are willing to route and the conditions under which they will route it. The motivations for these policies are many and are described in upcoming sections. In order to express and enforce policies, a simple policy definition language was developed. This language is sufficient for owners of overlay nodes to choose to route traffic based on their own requirements and gives node owners a means to express these requirements, such that other nodes within the overlay network can learn them. A mechanism is presented that allows these policies to be stored either in a distributed hash table or on a set of directory servers. The effectiveness of policy-based routing was tested using a simulated network. The affect of these routing policies, in terms of both additional network traffic and requirements for client software, was also assessed. Finally, a comparison was made between storing policy information in a distributed hash table, versus on a set of directory servers
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