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This paper introduces a novel architecture for implementing content-based pub/sub communications on top of structured overlay networks. This architecture overcomes some well-known limitations of existing infrastructures, i.e. lack of self-configuration and of adaptiveness to dynamic changes. This is achieved by devising a mediator stratum between the rich(More)
The Replication Logic is a set of protocols, mechanisms and services that allow a CORBA system to handle object replication. In this paper we present a specific implementation of a Replication Logic, namely Interoper-able Replication Logic (IRL), which exhibits nice properties like non-intrusion (i.e., the replication logic is built " above " the ORB) and(More)
In cooperative information systems, the quality of data exchanged and provided by different data sources is extremely important. A lack of attention to data quality can imply data of low quality to spread all over the cooperative system. At the same time, improvement can be based on comparing data, correcting them and thus disseminating high quality data.(More)
SUMMARY Enforcing strong replica consistency among a set of replicas of a service deployed across an asynchronous distributed system in the presence of crash failures is a real practical challenge. If each replica runs the consistency protocol bundled with the actual service implementation, this target cannot be achieved, as replicas need to be located over(More)
In this paper we present a performance evaluation of three Java group toolkits (JavaGroups, Spread and Appia) with respect to a specific application scenario: software replication using a three-tier architecture. We also compare performances of these Java group toolkits with Maestro/Ensemble which has been developed in C++. Results show that performances of(More)
Several efficient and very powerful algorithms exist for detecting changes in tree-based textual documents, such as those encoded in XML. An important aspect is still underestimated in their design and implementation: the quality of the output, in terms of readability, clearness and accuracy for human users. Such requirement is particularly relevant when(More)
A replication logic is the set of protocols and mechanisms implementing a software replication technique. A three-tier approach to replication consists in separating the replication logic from both clients and replicated servers by embedding such logic in a middle-tier. In this paper we first introduce the fundamental concepts underlying three-tier(More)
The ongoing diffusion of novel and mobile devices offers new ways to provide services across a growing set of network technologies. As a consequence, traditional information systems evolve to multichannel systems in which services are provided through different channels, being a channel the abstraction of a device and a network. This work proposes a quality(More)
Interceptors are a mean to add specific network-oriented capabilities (such as authentication, flow control, caching etc.) to a distributed application which runs over a mid-dleware without changing either the application code or the middleware's one. However, interceptors could be non-intuitive and this could in turn limit their use on a large scale. In(More)