Abstract
In this paper we describe a platform that enables Web site automation and monitoring. The platform automatically gathers high quality site activity data, both from the server and client sides. Web adapters, such as rec-ommender systems, can be easily plugged into the platform, and take advantage of the up-to-date activity data. The platform also includes a module to support the editor of the site to monitor and assess the effects of automation. We illustrate the features of the platform on a case study, where we show how it can be used to gather information not only to model the behavior of users but also the impact of the personalization mechanism. Copyright © 2008, Association for the Advancement of Artificial Intelligence.

Abstract

Abstract
We present MOB, a service-oriented scripting language, for programming mobile agents. We argue that combining the service-oriented and mobile agent paradigms provides a very natural model for programming a large class of distributed applications. In MOB, mobile agents in a network simultaneously provide and use services. The service interfaces constitute contracts that bind agents among themselves. The language features static type-checking to guarantee that contracts are respected at run-time. Other language features, such as redundant service providers, allow a certain degree of fault-tolerance by allowing applications to switch servers dynamically in case a failure is detected (e.g. a server crash). For these reasons, the target applications we envision more interesting to develop using MOB are services for networks with highly dynamic, volatile resources or simply highly adaptive, reconfigurable applications for more classical networks. The paper presents MOB and its implementation from an application programmer's and a systems developer's view. Copyright (C) 2007 John Wiley & Sons, Ltd.

Abstract
Nowadays applications produce infinite streams of data distributed across wide sensor networks. In this work we study the problem of continuously maintain a cluster structure over the data points generated by the entire network. Usual techniques operate by forwarding and concentrating the entire data in a central server, processing it as a multivariate stream. In this paper, we propose DGClust, a new distributed algorithm which reduces both the dimensionality and the communication burdens, by allowing each local sensor to keep an online discretization of its data stream, which operates with constant update time and (almost) fixed space. Each new data point triggers a cell in this univariate grid, reflecting the current state of the data stream at the local site. Whenever a local site changes its state, it notifies the central server about the new state it is in. This way, at each point in time, the central site has the global multivariate state of the entire network. To avoid monitoring all possible states, which is exponential in the number of sensors, the central site keeps a small list of counters of the most frequent global states. Finally, a simple adaptive partitional clustering algorithm is applied to the frequent states central points in order to provide an anytime definition of the clusters centers. The approach is evaluated in the context of distributed sensor networks, presenting both empirical and theoretical evidence of its advantages.

Abstract
Logtalk, an object oriented logic programming language, provides experimental support for multi-threading programming with selected back-end Prolog compilers. By making use of core, low-level Prolog predicates that interface with operating-system native threads, Logtalk provides a high-level set of directives and predicates that allows programmers to easily take advantage of modern multi-processor and multi-core computers without worrying about the details of creating, synchronizing, or communicating with threads. Logtalk multi-threading programming features include support for concurrent calls akin to and-parallelism and or-parallelism, non- deterministic thread goals, asynchronous calls, and predicate synchronization. The integration with the Logtalk object-oriented features allows objects to send and receive both synchronous and asynchronous messages and to call local predicates concurrently. Logtalk multi-threading features are orthogonal to object-oriented concepts and can be useful even in the context of plain Prolog.

Abstract
This paper presents the logic programming concept of thread-based competitive or-parallelism,, which combines the original idea of competitive or-parallelism with committed-choice nondeterminism and speculative threading. In thread-based competitive or-parallelism, an explicit. disjunction of subgoals is interpreted as a set of concurrent, alternatives, each running in its own thread. The subgoals compete for providing an answer and the first successful subgoal leads to the nation of the remaining ones. We discuss the implementation of competitive or-parallelism in the context, of Logtalk, all object-oriented logic programming language, and present results.