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On the Abstraction of a Categorical Clustering Algorithm
No full textDespite being one of the most common approach in unsupervised data analysis, a very small literature exists on the formalization of clustering algorithms. This paper proposes a semiring-based methodology, named Feature-Cluster Algebra, which is applied to abstract the representation of a labeled tree structure representing a hierarchical categorical clustering algorithm, named CCTree. The elements of the feature-cluster algebra are called terms. We prove that a specific kind of a term, under some conditions, fully abstracts a labeled tree structure. The abstraction methodology maps the original problem to a new representation by removing unwanted details, which makes it simpler to handle. Moreover, we present a set of relations and functions on the algebraic structure to shape the requirements of a term to represent a CCTree structure. The proposed formal approach can be generalized to other categorical clustering (classification) algorithms in which features play key roles in specifying the clusters (classes)
Facebook: a New Tool for Collecting Health Data?
No full textThis study investigates the use of social networks as a scientific tool for gathering medical data from young subjects while promoting healthier habits. Our first hypothesis is that social networks can facilitate epidemiological studies, reducing time and cost. The second question is whether social networks can enable the collection of data from young and healthy subjects who are otherwise beyond the reach of conventional social health polls.A Facebook application was created to collect data concerning adherence to the Mediterranean diet, considering the significant risk of cardiovascular and neurological degenerative diseases in subjects with poor adherence to a healthy diet. More than 1400 users were recruited in a short time without any promotional action. Collected data indicate that adherence to the Mediterranean diet is in general greater in older users vs young (p <0.01) and Italian vs Other Countries (mainly participants from the US) (p<0.03) while no statistical differences were found concerning gender.Results show that the proposed approach offers advantages in terms of reduced cost, faster data gathering and processing, and improved efficiency compared to a form-based epidemiology campaign. However, the initial network may influence the sample constitution in age and geographical location, especially if the spread does not become viral and autonomous.Based on the case study, we provide designers of Facebook apps with some simple guideline suggestions aimed at maximizing the heterogeneity of the sample, to collect significant data. The proposed scenario, suitable for collecting health data, can easily be extended to other fields
A personalized recommender system for pervasive social networks
No full textThe current availability of interconnected portable devices, and the advent of the Web 2.0,raise the problem of supporting anywhere and anytime access to a huge amount of content,generated and shared by mobile users. On the one hand, users tend to be always connectedfor sharing experiences and conducting their social interactions with friends andacquaintances, through so-called Mobile Social Networks, further improving their social inclusion.On the other hand, the pervasiveness of communication infrastructures spreadingdata (cellular networks, direct device-to-device contacts, interactions with ambient devicesas in the Internet-of-Things) makes compulsory the deployment of solutions able to filteroff undesired information and to select what content should be addressed to which users,for both (i) better user experience, and (ii) resource saving of both devices and network.In this work, we propose a novel framework for pervasive social networks, called PervasivePLIERS (p-PLIERS), able to discover and select, in a highly personalized way, contents ofinterest for single mobile users. p-PLIERS exploits the recently proposed PLIERS tag-basedrecommender system (Arnaboldi et al., 2016) as a context reasoning tool able to adapt recommendationsto heterogeneous interest profiles of different users. p-PLIERS effectivelyoperates also when limited knowledge about the network is maintained. It is implementedin a completely decentralized environment, in which new contents are continuously generatedand diffused through the network, and it relies only on the exchange of single nodes?knowledge during proximity contacts and through device-to-device communications. Weevaluated p-PLIERS by simulating its behavior in three different scenarios: a big event (Expo2015), a conference venue (ACM KDD?15), and a working day in the city of Helsinki. For eachscenario, we used real or synthetic mobility traces and we extracted real datasets fromTwitter interactions to characterize the generation and sharing of user contents
Quarter .it n. 2 - settembre 2016
No full textIl Quarter .it nasce nel 2013 ed ? un supplemento della testata giornalistica registrata Focus. it. Il quadrimestrale del Registro .it raccoglie dati statistici e commenti relativi al quadrimestre dell\u27anno di riferimento di registrazioni e tutte le attivit? correlate, di cui ci sia un dato rilevante da raccontare e di particolare rilievo. Allo stesso tempo raccoglie le news del Registro, progetti finanziati dall\u27anagrafe italiana dei domini Internet ed eventi. Il quadrimestrale esce sia nella versione italiana che in quella inglese.Il Quarter .it nasce nel 2013 ed ? un supplemento della testata giornalistica registrata Focus. it. Il quadrimestrale del Registro .it raccoglie dati statistici e commenti relativi al quadrimestre dell\u27anno di riferimento di?registrazioni e tutte le attivit? correlate, di cui ci sia un dato rilevante da raccontare e di particolare rilievo. Allo stesso tempo raccoglie le news del Registro, progetti finanziati dall\u27anagrafe italiana dei domini Internet ed eventi.?Il quadrimestrale esce sia nella versione italiana che in quella inglese
Ecco tre donne pioniere di Internet in Italia (ma sono di pi?)
No full textThe author explains the history of women who have made a contribution to the development of the Internet in ItalyCompetenza, passione e impegno sono il contributo che donne eccezionali hanno dato allo sviluppo di Internet in Italia
Rassegna stampa "Volare negli States con Registro.it" 14 Giugno 2015
No full textRaccoglie le notizie della stampa cartacea locale relative ad eventi (Internt Festival etc.) e altre particolarit? riguardanti il mondo delle rete e la sua rilevanza nel socialeRaccoglie le notizie della stampa cartacea locale relative ad eventi (Internt Festival etc.) e altre particolarit? riguardanti il mondo delle rete e la sua rilevanza nel social
Rassegna web "itCup: vince \u27Mindesk\u27, la penna in 3D" 9 ottobre 2015
No full textRaccoglie le pubblicazioni elettroniche locali riguardanti le attivit? e gli eventi (Internet Festival etc.) aventi come tema la rete e le sue applicazioni nel sociale.Raccoglie le pubblicazioni elettroniche locali riguardanti le attivit? e gli eventi (Internet Festival etc.) aventi come tema la rete e le sue applicazioni nel sociale
Decomposing Global Quantitative Properties into Local Ones.
No full textIn this paper we address the problem of identifying what local properties the sub-components of a system have to satisfy in order to guarantee a (security) property on the behaviour of the whole system.We associate each action with a value. Hence, we end up with quantitative properties on them, which are specified through a modal logic equipped with a parametric algebraic structure (i.e., a c-semiring). The aim is to have a value related to the satisfaction of a formula. Startingfrom the behaviour of a general distributed system (or context ), we propose a formal approach to decompose a global quantitative property intothe local quantitative properties to be satisfied by its sub-contexts
Exploiting Vehicles\u27 Reputation to Mitigate DoS Attack.
No full textRecently the convergence of safety and security needs in automotive systems is one of the main challenges of the research community. However, the different nature of safety and security metrics suggests that no individual assessment technique is sufficient, in isolation, to validate large systems that are intended to be both safe and secure. The introduction of new generation ICT systems into vehicles makes them potentially vulnerable to security attacks that may impact on the safety of passengers, pedestrians, and vehicle itself. Hence, entities involved in a communication have to be evaluated trustable by means of specific mechanisms of the vehicle or infrastructure system. This work aims at proposing an algorithm for the calculation of reputation of vehicles in a Vehicular Ad Hoc Network (VANET) based on the type and number of exchanged messages. The ultimate goal is to mitigate the Denial of Service (DoS) attack in such kind of communication by acting as a firewall with respect to not trustable vehicles. Indeed, the DoS is a security attack that affects the availability of network bandwidth. This may have an impact on safety of drivers and vehicles since it may prevent the communication and spread of important information for, e.g., human life