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Cloud-based computing networks have taken over the digital landscape. From small non-profits to large multinational corporations, more and more entities have been offloading computing effort to the cloud in order to take advantage of the increased cost-efficiency and scalability of cloud computing. One of the new types of cloud that have emerged is P2P cloud, which disengages from a traditional datacenter setup by allowing users to instead share their own computing hardware into a cloud to reap the benefits of cloud computing's advantages at an even lower cost. However, this new paradigm comes with a slew of challenges: (i) security, when operating with the devices of strangers and (ii) fairness when not operating in a market-based system. This paper aims to address these two issues by proposing an algorithm based on social credits for a P2P cloud system that uses a social network to establish its security measures. We implement our new Social Credit algorithm along with two other task-migration-based load-balancing algorithms adapted for a P2P social cloud in "Cloudsim Plus", and the relative gains are shown in terms of fairness and other related metrics. [ABSTRACT FROM AUTHOR]

The current state of the web, which is dominated by centralized cloud services, raises several concerns regarding different aspects such as governance, privacy, surveillance, and security. A way to address these issues is to decentralize the platforms by adopting new distributed technologies, such as IPFS and Blockchain, which follow a full peer-to-peer model. This work proposes a set of guidelines to design decentralized systems, taking the different trade-offs these technologies face with regard to their consistency requirements into consideration. These guidelines are then illustrated with the design of a decentralized questions and answers system. This system serves to illustrate a framework to create decentralized services and applications that uses IPFS and Blockchain technologies and incorporates the discussion and guidelines of the paper, providing solutions for data access, data provenance, and data discovery. Thus, this work proposes a framework to assist in the design of new decentralized systems, proposing a set of guidelines to choose the appropriate technologies depending on the relevant requirements; e.g., considering if Blockchain technology may be required or IPFS might be sufficient. [ABSTRACT FROM AUTHOR]

As a Distributed Hash Table (DHT), Skip Graph routing overlays are exploited in several peer-to-peer (P2P) services, including P2P cloud storage. The fully decentralized replication algorithms that are applicable to the Skip Graph-based P2P cloud storage fail on improving the performance of the system with respect to both the availability of replicas as well as their response time. Additionally, they presume the system as homogeneous with respect to the nodes’ latency distribution, availability behavior, and bandwidth, or storage. In this article, we propose Pyramid, which is the first fully decentralized utility- and locality-aware replication approach for Skip Graph-based P2P cloud storage systems. Pyramid considers the nodes as heterogeneous with respect to their latency distribution, availability behavior, bandwidth, and storage. Pyramid is utility-aware as it maximizes the average available bandwidth of replicas per time slot (e.g., per hour). Additionally, Pyramid is locality-aware as it minimizes the average latency between nodes and their closest replica. Our simulation results show that compared to the state-of-the-art solutions that either perform good in utility-awareness, or in locality-awareness, our proposed Pyramid improves both the utility- and locality-awareness of replicas with a gain of about 1.2 and 1.1 times at the same time, respectively. [ABSTRACT FROM AUTHOR]

User authentication has become an essential security element that enables a wide range of applications in P2P systems for higher security and safety requirements. In previous, many researchers worked on user authentication based on certificates, passwords, and feature-based authentication (e.g. face recognition, fingerprint detection, iris recognition, voice recognition). However, authentication using those technologies may fail because this information can be easily shared among users or synthesized. Also, there are several cyber and cryptography attacks. With the progress of the latest sensor technology, wearable as Microsoft Bands, Fitbit, and Garmin has provided for more information collecting opportunities. From those above point of views, this paper presents a novel user identification system based on the bio signal analysis of arm movement (3-axis accelerometer & 3-axis gyroscope) and electromyography (EMG) signal using Myo armband as a wearable user authentication system in P2P system that identifies users based on the bio-signal of movement of a person's arm. In this study, the gesture and EMG signals are obtained from the sensor and denoised using wavelet denoising algorithm. The denoised signals are analyzed using the envelope and cepstrum analysis for extracting the potential feature vector. Finally, the feature vector is used to train and identify a user using multi-class support vector machine (MC-SVM) with different kernel function for user authentication. For validating the proposed authentication model, signals are obtained from the arm movements, i.e., directions and hand gesture data using acceleration, gyroscope and EMG sensors of several subjects. According to the experimental results, the proposed model shows satisfactory performance. To evaluate the efficiency of the proposed systems, we measure and compare its classification accuracy with state-of-the-art algorithms. And the proposed algorithm outperforms with others. [ABSTRACT FROM AUTHOR]

To realize the vision of ubiquitous computing and reachability, major technological advances have been achieved to make smart portable devices both highly capable and affordable. To facilitate connectivity to the Internet, these smart devices are equipped with different network interface cards (4G, Bluetooth and Wi-Fi). However, such connectivity may become seriously reduced in places with intermittent network services and/or shortage of Wi-Fi coverage. This limitation may be seriously harmful in rescue scenarios during and after a disastrous event, since blocked users may become difficult to reach. In this paper we present a novel framework to overcome such issue by implementing a hot-spot accessible through device-to-device (D2D) links. In this work, Wi-Fi direct (WFD) is used in order to establish multi-hop P2P paths to the hot-spot. WFD has the same features that carries the standard Wi-Fi in terms of range and speed without using the infrastructure. Wi-Fi direct is largely emerging as a network technology standard enabled in the majority of smartphones. By exploiting nearby devices, which have Internet access, our framework enables users to publish contents. Moreover, our model is validated by using different smartphones and through extensive simulation experiments. [ABSTRACT FROM AUTHOR]

The current state of the web, which is dominated by centralized cloud services, raises several concerns regarding different aspects such as governance, privacy, surveillance, and security. A way to address these issues is to decentralize the platforms by adopting new distributed technologies, such as IPFS and Blockchain, which follow a full peer-to-peer model. This work proposes a set of guidelines to design decentralized systems, taking the different trade-offs these technologies face with regard to their consistency requirements into consideration. These guidelines are then illustrated with the design of a decentralized questions and answers system. This system serves to illustrate a framework to create decentralized services and applications that uses IPFS and Blockchain technologies and incorporates the discussion and guidelines of the paper, providing solutions for data access, data provenance, and data discovery. Thus, this work proposes a framework to assist in the design of new decentralized systems, proposing a set of guidelines to choose the appropriate technologies depending on the relevant requirements; e.g., considering if Blockchain technology may be required or IPFS might be sufficient.

Microgrids (MGs) are moving toward large-scale smart distributed networks which demand an efficient and reliable communication infrastructure to manage, control and monitor energy resources. With regard to this, publisher/subscriber event-based middleware has become relevant for large-scale distributed time applications because it allows decouple time and space between senders and receivers. Particularly the content publish/subscribe systems over structured peer-to-peer (P2P) networks has emerged to enhance scalability and dynamism of notification middleware systems. However, this type of systems use multicast routing schemes that still generate much network traffic and as a consequence an overload of the communication channel is produced. This results in inefficient network utilization and rapid depletion of network resources leading to unreliable operations, degradation of system performance and even instability of the MG. In this paper, a new content-based publish/subscribe notification middleware over structured P2P systems is proposed, such that smart MG communication requirements are met. This proposed system organizes the publications and subscriptions in a 1-D representation using the Hilbert space filling curve. Through this representation, innovative routing and matching algorithms are developed. Experimental results demonstrate that the proposed publisher/subscribe system significantly enhance efficiency of the system, network performance and the use of computational resources. [ABSTRACT FROM AUTHOR]

P2P networks have become a commonly used way of disseminating content on the Internet. In this context, constructing efficient and distributed P2P routing algorithms for complex environments that include a huge number of distributed nodes with different computing and network capabilities is a major challenge. In the last years, query routing algorithms have evolved by taking into account different features (provenance, nodes' history, topic similarity, etc.). Such features are usually stored in auxiliary data structures (tables, matrices, etc.), which provide an extra knowledge engineering layer on top of the network, resulting in an added semantic value for specifying algorithms for efficient query routing. This article examines the main existing algorithms for query routing in unstructured P2P networks in which semantic aspects play a major role. A general comparative analysis is included, associated with a taxonomy of P2P networks based on their degree of decentralization and the different approaches adopted to exploit the available semantic aspects. [ABSTRACT FROM AUTHOR]

In this paper a model based on user behaviour of P2P live streaming systems was developed in order to analyse one of the key QoS parameter of such systems, i.e. the probability of channel-satisfactory state, the impact of upload bandwidths and channels' popularity on the probability of channel-satisfactory state was also analysed. Results obtained have shown that channels with high number of patronising peers achieve satisfactory state easily while channels with low number of peers hardly attain satisfactory state. This called for the need to design a framework or incentive scheme for effective functionality of P2P live streaming systems which will favour all channels regardless of their popularities. [ABSTRACT FROM AUTHOR]

Locating relevant information in Peer-to-Peer (P2P) system is a challenging problem. Conventional approaches use flooding to locate the content. It is no longer applicable due to massive information available upfront in the P2P systems. Sometime, it may not be even possible to return small percent of relevant content for a search if it is an unpopular content. In this paper, we present adaptive semantic P2P content indexed system. Content indices are generated using topical semantics of documents derived using Wordnet ontology. Similarities between document hierarchies are computed using information theoretic approach. It enables locating and retrieval of contents with minimum document movement, search space and nodes to be searched. Results illustrate that our work can achieve results better than Content Addressable Network (CAN) semantic P2P Information Retrieval (IR) system. Contrary to CAN semantic P2P IR system, we have used content aware and node aware bootstrapping instead of random bootstrapping of search process. [ABSTRACT FROM AUTHOR]

This paper identifies and analyzes the key design approaches that have been proposed over the last decade to construct a peer-to-peer (P2P) networked virtual environment (NVE) systems. We discuss each approach, their advantages and drawbacks, and examine several representative P2P-based NVE systems based on the presented approaches, thus providing the background and literature review of P2P NVEs. [ABSTRACT FROM AUTHOR]

Trust management is not an easy task in a peer-to-peer system because a peer is not able to know all the other peers in the system, and therefore, it is not obvious to exchange documents safely. Accordingly, an efficient model of trust management is necessary to manage the trust between peers in order to, quickly and efficiently, make the difference between potentially malicious and benevolent peers before downloading a document. Several approaches have been developed to calculate the indirect trust value. These approaches are based on sequential search of trust paths. In this paper and in order to optimize the research response time of trust paths, we propose a new distributed model called Trust_Path to search all trust paths between two peers that have no direct knowledge. This search is performed by propagation, in a distributed manner, to all known peers. The experiments realized on a network of 16 servers, on which we have set up virtual machines, show that the response time of search of trust paths with the parallel execution using Trust_Path model is much faster than sequential execution and that its acceleration increases according to the number of nodes. The simulation results show that our model can be applied to a large-scale environment.Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In P2P systems, each peer has to obtain information of other peers and propagate the information to other peers through neighboring peers. Thus, it is important for each peer to have some number of neighbor peers. Moreover, it is more significant to discuss if each peer has reliable neighbor peers. In reality, each peer might be faulty or might send obsolete, even incorrect information to the other peers. We have implemented a P2P platform called JXTA-Overlay, which defines a set of protocols that standardize how different devices may communicate and collaborate among them. It abstracts a new layer on the top of JXTA through a set of primitive operations and services that are commonly used in JXTA-based applications and provides a set of primitives that can be used by other applications, which will be built on top of the overlay, with complete independence. JXTA-Overlay provides a set of basic functionalities, primitives, intended to be as complete as possible to satisfy the needs of most JXTA-based applications. In this paper, we present two fuzzy-based systems (called FRS1 and FRS2) to improve the reliability of JXTA-Overlay P2P platform. We make a comparison study between the fuzzy-based reliability systems. Comparing the complexity of FRS1 and FRS2, the FRS2 is more complex than FRS1. However, it considers also the security; therefore, it can be used in real application for secure systems. [ABSTRACT FROM AUTHOR]

Peer-to-peer (P2P) networks, will be very important for future distributed systems and applications. In such networks, peers are heterogeneous in providing the services and they do not have the same competence of reliability. Therefore, it is necessary to estimate whether a peer is trustworthy or not for file sharing and other services. In this paper, we propose two fuzzy-based trustworthiness system for P2P communication in JXTA-overlay. System 1 has only one fuzzy logic controller (FLC) and uses four input parameters: mutually agreed behaviour ( MAB), actual behaviour criterion ( ABC), peer disconnections ( PD) and number of uploads ( NU) and the output is peer reliability ( PR). System 2 has two FLCs. In FLC1 use three input parameters: number of jobs ( NJ), number of connections ( NC) and connection lifetime ( CL) and the output is actual behavioural criterion ( ABC). We use ABC and reputation ( R) as input linguistic parameters for FLC2 and the output is peer reliability ( PR). We evaluate the proposed systems by computer simulations. The simulation results show that the proposed systems have a good behaviour and can be used successfully to evaluate the reliability of the new peer connected in JXTA-overlay. [ABSTRACT FROM AUTHOR]

Social applications mine user social graphs to improve performance in search, provide recommendations, allow resource sharing and increase data privacy. When such applications are implemented on a peer-to-peer (P2P) architecture, the social graph is distributed on the P2P system: the traversal of the social graph translates into a socially-informed routing in the peer-to-peer layer. In this work we introduce the model of a projection graph that is the result of decentralizing a social graph onto a peer-to-peer network. We focus on three social network metrics: degree, node betweenness and edge betweenness centrality and analytically formulate the relation between metrics in the social graph and in the projection graph. We demonstrate with an application scenario on real social networks the usability of the projection graph properties in designing social search applications and unstructured P2P overlays that exhibit improved performance and reduced overhead over baseline scenarios. [ABSTRACT FROM PUBLISHER]

Peer‐to‐peer (P2P) video streaming systems enable video data exchange between peers by reducing the overload of the servers while utilising network resources. Multi‐agent systems (MASs), including many autonomous and intelligent software agents working on behalf of video peers, may also provide a feasible infrastructure for the implementation of P2P video streaming systems. Within this context, research on the use of software agents in video streaming systems has recently emerged. In this study, the authors discuss the development of an agent‐based P2P video streaming system. Software engineering of the MAS with covering various aspects such as agent internals and interactions in the system is described. Performance evaluation of the proposed agent‐based P2P system comparing with the popular in‐use streaming application is also reported. Results show that a well‐defined behaviour of a parent selection software agent can improve the continuity index in P2P video streaming systems. Therefore the users in the system can watch video in a better quality and lower end‐to‐end delay comparing with the currently used video streaming applications. They also examine that peer welcoming (traffic localisation) behaviour of the agents decreases the internal Internet service provider traffic significantly. [ABSTRACT FROM AUTHOR]

Abstract: In peer-to-peer (P2P) networks, trust management is a key tool to minimize the impact of malicious nodes. EigenTrust is claimed to be one of the most powerful distributed reputation management systems focused on P2P file-sharing applications. It is the theoretical base of other systems, and it has also been directly modified in an attempt to improve its performance. However, none of them give appropriate importance to all the information about transactions. This paper proposes an enhancement of EigenTrust, which considers unsatisfactory transactions in greater depth. Pos&Neg EigenTrust is able to obtain a blacklist of the identities of the malicious nodes. Therefore, it is able to significantly reduce the number of unsatisfactory transactions in the network. [Copyright &y& Elsevier]

SUMMARY Peer-to-peer (P2P) systems enjoy wide adoption from internet users. Success of P2P architecture is due to its ability to scale and organize dynamically the traffic according to the user resources and requests. However, P2P adoption is constrained in non-real time applications, like content distribution and file sharing. The major reason behind this fact is the inability of P2P to deliver content within user-desired bit rates by making optimal use of network resources. In this paper we focus on the solution and implementation of technical problems toward a complete system implementation that delivers live multimedia streaming through P2P architecture by the use of IMS. The content indexing and discovery, the scalable management and the distributed optimization of the graph that connects participating peers, the distributed scheduling mechanisms for data exchange, a scalable monitoring architecture and a bandwidth control mechanism constitute the major components toward a complete scalable multimedia streaming system offering streaming stability and high performance. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]