6809 research outputs found
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Breve ricognizione sui criteri di partecipazione alle gare d\u27appalto e sulla disciplina del soccorso istruttorio alla luce dei significativi pareri emanati dalle competenti Autorit? in materia
No full textObiettivo di questo nota tecnica ? quello di fornire una breve ricognizione dei requisiti generali e speciali previsti dal decreto legislativo 12 aprile 2006 n. 163 recante il Codice dei contratti pubblici relativi a lavori, servizi e forniture in attuazione delle direttive 2004/17/CE e 2004/18/CE che debbono essere posseduti dagli operatori economici che intendono contrarre con la pubblica amministrazione, nonch? relativamente alle modalit? i di verifica del possesso di tali requisiti.Obiettivo di questo nota tecnica ? quello di fornire una breve ricognizione dei requisiti generali e speciali previsti dal decreto legislativo 12 aprile 2006 n. 163 recante il Codice dei contratti pubblici relativi a lavori, servizi e forniture in attuazione delle direttive 2004/17/CE e 2004/18/CE che debbono essere posseduti dagli operatori economici che intendono contrarre con la pubblica amministrazione, nonch? relativamente alle modalit? i di verifica del possesso di tali requisiti
Correlating Languages and Sentiment Analysis on the basis of Text-based Reviews
No full textCustomer experiences, in the shape of online reviews, influence other customers and in general, contribute to build a perception of a destination. This work presents the conclusions of a survey to gather user text-based reviews about several categories of destination-related information (accommodation, restaurants, attractions and Points of Interest) from three well-known social media sources (Facebook, FourSquare and GooglePlaces) about eight worldwide destinations with a high overnight rate. Several hypotheses about the correlation between the language and sentiment features of the reviews have been validated over a large dataset of reviews. For example, the analysis detected that the highest number of reviews in a destination is written in the same official language spoken in that place. Furthermore, Dutch speaking people are more positive when writing a review. Finally, English, Italian and Spanish speakers seem to prefer FourSquare while German and French people are quite evenly distributed among FourSquare and GooglePlaces
LoSeRO: A Locality Sensitive Routing Protocol in Opportunistic Networks
No full textUser trajectories can be used to extrapolate personal infor- mation such as interests and movement patterns. Extrapo- lating this information is especially important in the context of opportunistic networks, which take advantage of human mobility and their interactions to deliver messages to rele- vant users. In this paper, we propose a Geo-casting routing protocol called LoSeRO for opportunistic networks, which uses knowledge of the locations most frequently visited by a user to route messages. LoSeRO forwards messages ?in a multicasting way? to all users who have a mobility profile that intersects the packet?s destination zone. In particular, users? mobility profile is defined based on pre-defined zones, and LoSeRO generates a mobility vector, called MobyZone, populated by the most n-frequented zones. Thus, if the des- tination zone of the packet belongs to the MobyZone of a user, then the user is chosen as valid candidate for receiv- ing the packet. Efficiency of our protocol has been evalu- ated using different metrics, such us coverage, precision and success rate, and compared to that of state-of-the-art geo- casting protocols. Simulations show that LoSeRO reaches the best compromise among the mentioned evaluation met- rics. Moreover, results highlight that the performance of our protocol improves as the number of network users increases
Privacy-preserving Data Allocation in Decentralized Online Social Networks
No full textDistributed Online Social Networks (DOSNs) have been recently proposed as an alternativeto centralized solutions to allowa major control of the users over their own data. Since there is no centralized service provider which decides the term of service, the DOSNs infrastructure exploits users\u27 devices to take on the online social network services. In this paper, we propose a data allocation strategy for DOSNs which exploits the privacy policies of the users to increase the availability of the users\u27 contents without diverging from their privacy preferences. A set of replicas of the profile\u27s content of a user Uare stored on the devices of other users who are entitled to access the profile according to U\u27s privacy policies.The experimental results obtained by the simulations on traces taken from a realsocial network show the effectiveness of our approach
Smartphone-based crowdsourcing for estimating the bottleneck capacity in wireless networks
No full textCrowdsourcing enables the fine-grained characterization and performance evaluation of today?s large-scale networks using the power of the masses and distributed intelligence. This paper presents SmartProbe, a system that assesses the bottleneck capacity of Internet paths using smartphones, from a mobile crowdsourcing perspective. With SmartProbe measurement activities are more bandwidth efficient compared to similar systems, and a larger number of users can be supported. An application based on SmartProbe is also presented: georeferenced measurements are mapped and used to compare the performance of mobile broadband operators in wide areas. Results from one year of operation are included
Risk analysis of Android applications: A user-centric solution
No full textAndroid applications (apps) pose many risks to their users, e.g., by including code that may threaten user privacy or system integrity. Most of the current security countermeasures for detecting dangerous apps show some weaknesses, mainly related to users? understanding and acceptance. Hence, users would benefit from an effective but simple technique that indicates whether an app is safe or risky to be installed. In this paper, we present MAETROID (Multi-criteria App Evaluator of TRust for AndrOID), a framework to evaluate the trustworthiness of Android apps, i.e., the amount of risk they pose to users, e.g., in terms of confidentiality and integrity. MAETROID performs a multi-criteria analysis of an app at deploy-time and returns a single easyto-understand evaluation of the app?s risk level (i.e., Trusted, Medium Risk, and High Risk), aimed at driving the user decision on whether or not installing a new app. The criteria include the set of requested permissions and a set of metadata retrieved from the marketplace, denoting the app quality and popularity. We have tested MAETROID on a set of 11,000 apps both coming from Google Play and from a database of known malicious apps.The results show a good accuracy in both identifying the malicious apps and in terms of false positive rate
Ego Network Structure in Online Social Networks and its Impact on Information Diffusion
No full textIn the last few years, Online Social Networks (OSNs) attracted the interest of a large number of researchers, thanks to their central role in the society. Through the analysis of OSNs, many social phenomena have been studied, such as the viral diffusion of information amongst people. What is still unclear is the relation between micro-level structural properties of OSNs (i.e. the properties of the personal networks of the users, also known as ego networks) and the emergence of such phenomena. A better knowledge of this relation could be essential for the creation of services for the Future Internet, such as highly personalised advertisements fitted on users? needs and characteristics. In this paper, we contribute to bridge this gap by analysing the ego networks of a large sample of Facebook and Twitter users. We show that micro-level structural properties of OSNs are interestingly similar to those found in social networks formed offline. In particular, online ego networks show the same structure found offline, with social contacts arranged in layers with compatible size and composition. From the analysis of Twitter ego networks, we have been able to find a direct impact of tie strength and ego network circles on the diffusion of information in the network. Specifically, there is a high correlation between the frequency of direct contact between users and her friends in Twitter (a proxy for tie strength), and the frequency of retweets made by the users from tweets generated by their friends. We analysed the correlation for each ego network layer identified in Twitter, discovering their role in the diffusion of information
Stateful Data Usage Control for Android Mobile Devices
No full textModern mobile devices allow their users to download data from the network, such as documents or photos, to store local copies and to use them.Many real scenarios would benefit from this capability of mobile devices to easily and quickly share data among a set of users but, in case of critical data, the usage of these copies must be regulated by proper security policies. To this aim, we propose a framework for regulating the usage of data when they have been downloaded on mobile devices, i.e., they have been copied outside the producer\u27s domain. Our framework regulates the usage of the local copy by enforcing the Usage Control policy which has been embedded in the data by the producer.Such policy is written in UXACML, an extension of the XACML language for expressing Usage Control model based policies, whose main feature is to include predicates which must be satisfied for the whole execution of the access to the data.Hence, the proposed framework goes beyond the traditional access control capabilities, being able to interrupt an ongoing access to the data as soon as the policy is no longer satisfied.This paper details the proposed approach, defines the architecture and the workflow of the main functionalities of the proposed framework,describes the implementation of a working prototype for Android devices, presents the related performance figures, and discusses the security of the prototype
Costs and benefits of orthographic inconsistency: Evidence from a cross-linguistic comparison.
No full textWe compared reading acquisition in English and Italian children up to late primary school analyzing RTs and errors as a function of various psycholinguistic variables and changes due to experience. Our results show that reading becomes progressively more reliant on larger processing units with age, but that this is modulated by consistency of the language. In English, an inconsistent orthography, reliance on larger units occurs earlier on and it is demonstrated by faster RTs, a stronger effect of lexical variables and lack of length effect (by fifth grade). After 5 years of schooling, children of the two languages read with similar accuracy, but the English children remain faster. However, not all English children are able to master this mode of processing yielding larger inter-individual variability. In Italian, a consistent orthography, reliance on larger units occurs later and it is less pronounced. This is demonstrated by larger length effects which remain significant even in older children and by larger effects of a global factor (related to speed of orthographic decoding) explaining changes of performance across ages. Our results show the importance of considering not only overall performance, but inter-individual variability and variability between conditions when interpreting cross-linguistic differences
Ritrovamento in Sardegna di Lamprocoris spiniger (Dallas, 1849), Scutelleride esotico: un\u27invasione fallita?
No full textThe knowledge of the fate of exotic species that reached new areas is very important to give an idea on the number of species that manage to settle and eventually to become invasive. For this reason it seems to be interesting report the finding in Sardinia of a species native to Asia, Lamprocoris spiniger (Heteroptera Scutelleridae), new for Europe and never found again