Résultat de la recherche
Experimenting with gnutella communities
Computer networks or distributed systems in general may be regarded as communities where the individual components, be they entire systems, application software or users, interact in a shared environment. Such communities dynamically evolve with components or nodes joining and leaving the system. Their own individual activities affect the community's behavior and vice versa. This paper discusses various practical experiments undertaken to investigate the behavior of a real system, the Gnutella network, which represents such a community. Gnutella is a distributed Peer-to-Peer data-sharing system without any central control. It turns out that most interactions between nodes do not last long and much of their activity is devoted to finding appropriate partners in the network. The experimental results presented have been obtained from a Java implementation of Gnutella running in the open Internet environment, and thus in unknown and quickly changing network structures heavily depending on chance.
Message chains and disjunct paths for increasing communication performance in large networks
In this paper we propose a simple powerful method to increase communication performance in large networks such as the Internet. Our approach is based on the usage multiple disjunct paths for the transmitting data from one node to another one. The method exploits the dense connectivity of the Internet by making use of the different routes engaged in communications originating from different nodes to one target nodes. We show that depending on the bandwidth offered and the amount of data to be transfered, a linear speedup can be achieved. An experimental implementation of the method within the WOS framework confirms the theoretical analysis of the method.
SecAdvise: A security mechanism advisor
The proliferation of incompatible e-commerce systems applying different security technologies imposes difficult choices on all the concerned parties. In this context, the purpose of this research is to provide the necessary background to develop a security advisor (SecAdvise), which will make it possible to integrate the security mechanisms and the dynamic selection of the various mechanisms between several parties wishing to conduct business transactions safely. Such an advisor aims multiple goals: overcoming compatibility and interoperability problems, evaluating and reducing technological security risks, and enhancing trust.
The GIPSY architecture
Intensional Programming involves the programming of expressions placed in an inherent multidimensional context space. It is an emerging and highly dynamic domain of general application. The fast growing computer connectivity allows for more and more efficient implementation of distributed applications. The paradigm of intensionality inherently includes notions of parallelism at different levels. However, the currently available intensional programming software tools are becoming obsolete and do not enable us to further push forward practical investigations on the subject. Experience shows that the theoretical advancement of the field has come to acceptable maturity. Consequently, new powerful tools for intensional programming are required. In this paper, we present the design of a General Intensional Programming System (GIPSY). The design and implementation of the GIPSY reflect three main goals: generality, adaptability and efficiency.