DIPARTIMENTO DI TECNOLOGIE DELL'INFORMAZIONE

Compte tenu de l'évolution rapide des Technologies de l'Information, la création de nouvelles méthodes d'enseignement s'impose afin de permettre aux étudiants de maitriser les contours difficiles du programme d'enseignement. De nos jours, dans le soucis d'amélioration de l'enseignement des Technologies de l'Information et de la Communication (TIC), plusieurs Universités et Institutions voudraient mettre à la disposition des étudiants une solution basée sur les environnements virtuels d'étude pour leur permettre d'acquérir des aptitudes pratiques suite à la théorie acquise dans l'environnement classique d'enseignement. Mais elles sont limitées par le coût onéreux des environnements virtuels commerciaux qui sont proposés sur le marché. Cet article a pour but de décrire OVL (Open Virtual Lab), l'environnement virtuel « open source » mis en place par l'Université de Milan et qui est utilisé à distance par des Institutions d'outre-mer pour leurs programmes de formations dans le domaine de la configuration et la sécurité des réseaux. En particulier, nous présenterons les avantages liés à l'apprentissage à distance, qu'un tel environnement procure depuis quelques années aux étudiants de l'Université d'Abomey-Calavi (Bénin) à travers leurs projets d'examen et leurs projets de thèse de Master Professionnel. Summary : Given the rapid evolution of information technologies, new teaching methods is needed to enable students to master the difficult contours of the curriculum. Nowadays, in order to improve the teaching of Information Technology and Communication (ICT), several universities and institutions would like to make available to students a solution based on virtual environments for study enabling them to acquire practical skills after the theory gained in the classic environment of education. But they are limited by the cost of expensive commercial virtual environments that are offered on the market. This article aims to describe OVL (Open Virtual Lab), the virtual "open source" set up by Università degli Studi di Milano and used by remote institutions overseas for their training programs in configuration and network security. In particular, we will present the advantages of distance learning that such environment provides the last few years to students at the University of Abomey-Calavi (Benin) through their exam projects and Master Professional thesis.

The Common Criteria standard provides an infrastructure for evaluating security functions of IT products and for certifying that security policies claimed by product suppliers are correctly enforced by the security functions themselves. Certifying Open Source software (OSS) can pave the way to OSS adoption in a number of security-conscious application environments. Recent experiences in certifying Linux distributions has pointed out the problem of finding a mapping between descriptions of OSS security functions and existing test suites developed independently, such as the Linux Test Project. In this paper, we describe a mechanism, based on matching techniques, which semiautomatically associates security functions to existing test suite such as the ones developed by Open Source communities.

Information sharing plays a role of paramount importance in modern supply chain environments. In fact, the elements that compose the chain need to share information about sensitive aspects of their business in order to build more accurate and profitable supply plans. In this paper, we describe how the increasing of information released increases the overall economic results of the whole chain, and how this information can be protected, exploiting secure computation techniques, to reduce the risk of data disclosure and prevent quasi-altruistic or selfish behaviors without interfering with the chain's normal operation, and in particular with the minimization of the cost function.

XML is today the most used data interchange format for business-to-business applications. Indeed, an increasing amount of data is created and published over the Internet every day in XML format. Moreover, organizations need more and more to share sets of XML documents usually managed via a common XML repository. XML copyright protection and source tracking have become strong requirements for collaborative environments. In the literature, XML-specific fingerprinting mechanisms have been proposed, inspired by similar work on relational data. However their robustness is impaired by the fact that an XML file can undergo a set of updates that change both the file structure and content. In this paper, we propose a novel watermarking schema for XML files. This solution is based first on an adequate selection of XML locators, i.e. document fragments targeted to embed the watermark. Watermark retrieval is achieved thank to a set of personalized fuzzy queries that reconstruct the locators that contain the watermark. We show theoretically the watermark robustness against possible XML file transformations; then, we present some initial experiments that validate the approach.

Today, XML is the most used data interchange format for business-to-business applications. Indeed, an increasing amount of data in XML format is created and published over the Internet every day. Moreover, organizations need more and more to share sets of XML documents usually managed via a common XML repository. XML integrity and authenticity have become strong requirements for applications like web services that exchange messages in such format. XML signature aims to guarantee these properties but it cannot avoid attackers to intercept and change the structure of the XML message. A very common attack to XML Signature called XML Signature Wrapping(XSW) attack represents a big issue in web services security as SOAP messages -which are XML signed files-could be corrupted. In this paper, we propose a countermeasure to the XML Signature wrapping attack that makes use of XML watermarking techniques. In our proposal we express constraints on the schema of the XML document and fix its structure using an absolute coordinate system whose values are embedded within the file as a watermark.

Abstract This paper presents an architecture of a contextaware pro-active recommender system. The system uses contextual information in order to provide recommendations that are more suitable to the particular individual user. Reduction-based theory has been used in order to be able to use the contextual information besides the user and item components of traditional two dimensional recommender systems. The proposed recommender system provides recommendations pro-actively by using multi-agent technology.

Mutual synchronization is a common phenomenon in biology. It occurs at different levels, ranging from the small scale of the cardiac pace-maker cells of the SA (Sino-Atrial) and AV (Atrium-Ventricular) nodes in the human hearth that synchronously fire and give the pace to the whole muscle, to the coordinated behaviours of crickets that chirp in unison and of fireflies that flash together in some parts of southeast Asia.

Abstract In this study, surface ECG signals recoded during atrial fibrillation (AF) episodes have been investigated to assess the presence of scaling behaviors. The ECG signals consisted of one minutes recordings coming from the 2004 Computers in Cardiology Challenge database. After having removed the ventricular related activity, the residual ECG signal (rECG) was analyzed using detrended fluctuation analysis (DFA). We documented the existence of two scaling regions in the signals.

Abstract In this work, the analysis of atrial signals recorded during atrial fibrillation was pursued using two spectral estimators designed for series with missing data: the Lomb periodogram (LP) and the iterative singular spectrum analysis (ISSA). The main aim is to verify if subtraction of the ventricular activity might be avoided by performing spectral analysis on those ECG intervals where such activity is absent,(ie the TQ intervals), at least to estimate the dominant atrial fibrillatory frequency (FF).

Abstract A variety of problems in engineering and geology involve spreading cooling non-Newtonian fluids. If the fluid is relatively shallow and spreads slowly, lubrication-style asymptotic approximations can be used to build reduced models for the spreading dynamics. The centrepiece of such models is a nonlinear diffusion equation for the local fluid thickness, and ideally this should become coupled to a correspondingly simple equation determining the local temperature field.

Abstract In this study, we suggest a method for automatic measurement of the QT interval. The method derives from the standard technique of" selective beat averaging". To overcome those situations in which the templates are noisy as they arise from averaging only a small number of beats, two separate patterns were used: one for the QRS complex and the other for the T wave. The templates were carefully matched with the beats by cross-correlation, using an iterative refinement process.

Abstract The V-index is a recently-proposed metric related to repolarization heterogeneity (RH) across the myocardium, a key quantity for the development of arrhythmias. The metric is derived from multi-leads ECG recordings and this paper investigates two of its properties: i) the dependency on the lead system (Frank's orthogonal vs. 12 standard leads); ii) the influence of errors in the location of the T-end position. The first investigation was performed by simulations, using a forward ECG model (ECGSIM).

Ensembles of low-order dynamical systems are often used to model the interaction, competition, and synchronization among dynamically coupled, but distinct, objects. In this genre, coupled map lattices are one of the simplest and widely used objects. Despite their simplicity, coupled maps show a wide range of behavior, both with global coupling „in which each map is affected by the dynamics of all other maps; a mean field interaction… and local coupling „where each map interacts only with its nearest neighbors….