Mobile support in CSCW applications and groupware development frameworks

Computer Supported Cooperative Work (CSCW) is an established subset of the field of Human Computer Interaction that deals with the how people use computing technology to enhance group interaction and collaboration. Mobile CSCW has emerged as a result of the progression from personal desktop computing to the mobile device platforms that are ubiquitous today. CSCW aims to not only connect people and facilitate communication through using computers; it aims to provide conceptual models coupled with technology to manage, mediate, and assist collaborative processes. Mobile CSCW research looks to fulfil these aims through the adoption of mobile technology and consideration for the mobile user. Facilitating collaboration using mobile devices brings new challenges. Some of these challenges are inherent to the nature of the device hardware, while others focus on the understanding of how to engineer software to maximize effectiveness for the end-users. This paper reviews seminal and state-of-the-art cooperative software applications and development frameworks, and their support for mobile devices

Data Management in the APPA System

International audienceCombining Grid and P2P technologies can be exploited to provide high-level data sharing in large-scale distributed environments. However, this combination must deal with two hard problems: the scale of the network and the dynamic behavior of the nodes. In this paper, we present our solution in APPA (Atlas Peer-to-Peer Architecture), a data management system with high-level services for building large-scale distributed applications. We focus on data availability and data discovery which are two main requirements for implementing large-scale Grids. We have validated APPA's services through a combination of experimentation over Grid5000, which is a very large Grid experimental platform, and simulation using SimJava. The results show very good performance in terms of communication cost and response time

Group trust yields improved scalability and anomalydetection for p2p systems

This paper implements an existing computational model of trust and reputationapplied to a P2P environment, and extends the approach using a novel group trust calculationthat demonstrates improved scalability and anomaly detection for P2P systems. Our analysis isbased on results obtained by simulating a P2P environment using the JXTA open source platform.A trust and reputation model was implemented in the same platform, allowing to constructinga baseline for the behavior of the nodes using combined trust and reputation coefficients in ascenario without malicious nodes. Then simulations were conducted with malicious nodes andthe effect of trust and reputation factors were analyzed regarding their influence on the anomalydetection capacity and scalability in P2P communications. Several simulation scenarios wereconfigured and explored, considering the presence of different number of malicious nodes in theP2P environment, with both constant and variable behavior. Other scenarios included calculationsof combined trust and reputation for node groups. The results show that group trust ensure moreinteractions among nodes, even in the presence of a large number of malicious nodes (60% of thetotal), besides providing focused identification of malicious nodes inside groups

The essence of P2P: A reference architecture for overlay networks

The success of the P2P idea has created a huge diversity of approaches, among which overlay networks, for example, Gnutella, Kazaa, Chord, Pastry, Tapestry, P-Grid, or DKS, have received specific attention from both developers and researchers. A wide variety of algorithms, data structures, and architectures have been proposed. The terminologies and abstractions used, however, have become quite inconsistent since the P2P paradigm has attracted people from many different communities, e.g., networking, databases, distributed systems, graph theory, complexity theory, biology, etc. In this paper we propose a reference model for overlay networks which is capable of modeling different approaches in this domain in a generic manner. It is intended to allow researchers and users to assess the properties of concrete systems, to establish a common vocabulary for scientific discussion, to facilitate the qualitative comparison of the systems, and to serve as the basis for defining a standardized API to make overlay networks interoperable