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Security Trend Analysis with CVE Topic Models
No full textWe study the vulnerability reports in the Common Vulnerability and Exposures (CVE) database by using topic models on their description texts to find prevalent vulnerability types and new trends semi-automatically. In our study of the 39,393 unique CVEs until the end of 2009, we identify the following trends, given here in the form of a weather forecast: PHP: declining, with occasional SQL injection. Buffer Overflows: flattening out after decline. Format Strings: in steep decline. SQL Injection and XSS: remaining strong, and rising. Cross-Site Request Forgery: a sleeping giant perhaps, stirring. Application Servers: rising steeply
The Impact of Vertical Integration and Outsourcing on Firm Efficiency: Evidence from the Italian Machine Tool Industry
No full textIn this paper we made use of an econometric approach to efficiency analysis in order to capture the role of vertical integration and outsourcing on firm's efficiency. Vertical integration is considered an indicator of structure, while outsourcing represents the process of its change. We consider inefficiency measures as indicators of organizational heterogeneity, related to the firm's choices regarding the phases of the production process that are under its control. We find support for the hypothesis of a relationship between vertical integration and efficiency. The results on outsourcing activity, and in particular the interaction between outsourcing and vertical structure, indicate that heterogeneous patterns, far from tending to cancel out each other as a consequence of common external changes, are reinforcing. Moreover, the sensitivity of inefficiency variance to the cycle, indicate that different firms may have different dynamic properties
Infinite horizon optimal control problems with multiple thermostatic hybrid dynamics
No full textWe study an optimal control problem for a hybrid system exhibiting several internal switching variables whose discrete evolutions are governed by some delayed thermostatic laws. By the dynamic programming technique we prove that the value function is the unique viscosity solution of a system of several Hamilton-Jacobi equations, suitably coupled. The method involves a contraction principle and some suitably adapted results for exit-time problems with discontinuous exit cost
State independence for tunneling processes through Black Hole horizons and Hawking radiation
No full textTunneling processes through black hole horizons have recently been investigated in the framework of WKB theory discovering interesting interplay with the Hawking radiation. In this paper we instead adopt the point of view proper of QFT in curved spacetime, namely, we shall use some scaling limit techniques in order to obtain the leading order of the correlation functions related with tunneling processess through a Killing horizon. The computation will be done with respect to a certain large class of reference states for scalar elds. In the limit of sharp localization either on the external side or on opposite sides of the horizon, the quantum correlation functions are of thermal nature, where in both cases the characteristic temperature is the Hawking one. Our approach is valid for every stationary charged rotating non extremal black hole, however, since the computation is completely local, it covers the case of a Killing horizon which just temporarily exist in some nite region too. These results give a strong support to the idea that the Hawking radiation, which is detected at future innity and needs some global structures to be dened, is actually related to a local phenomenon which holds also for geometric structures (local Killing horizons) existing just for a while
Dalla favola al proverbio, dal proverbio alla favola: Genesi e fortuna dell’elemento gnomico fedriano
No full textDopo un'introduzione sulla stretta interrelazione tra il genere favolistico e quello paremiografico in ambito classico e mediolatino, si fornisce il catalogo completo degli elementi gnomici presenti nelle singole favole fedriane o nelle loro riduzioni mediolatine quali gli anonimi Iocalis e Minor fabularius o la Fecunda ratis di Egberto di Liegi
The first Latin translation
No full textAlthough Agostino Nifo produced a Latin reworking of Il Principe before Machiavelli’s treatise saw print, the first proper Latin translation was not completed until 1560.
Commissioned by the publisher Pietro Perna, it was carried out by the Reformed Umbrian exile Silvestro Tegli and published in Basle as a work of politico-religious Reformist propaganda. The translation was essentially faithful to the original, except for the omission of some passages whose content was too compromising and a stylistic reworking marked by the use of rhetorical amplificatio, as was typical of literary prose in the sixteenth century. With its 14 republications and re-printings in the space of 60 years, it helped spread Machiavelli’s text throughout Europe, and its fame was only surpassed by Hermann Conring’s Latin translation published in 1660, which however largely recast the original for ideological reasons
Lightweight Parsing of Classications into Lightweight Ontologies
No full textUnderstanding metadata written in natural language is a premise to successful automated integration of large scale, language-rich, classications such as the ones used in digital libraries. We analyze the natural language labels within classication by exploring their syntactic structure, we then show how this structure can be used to detect patterns of language that can be processed by a lightweight parser with an average accuracy of 96.82%. This allows for a deeper understanding of natural language metadata semantics, which we show can improve by almost 18% the accuracy of the automatic translation of classications into lightweight ontologies required by semantic matching, search and classication algorithms
A semantic geo-catalogue implementation for a regional SDI
No full textIn this paper we report our work on the implementation of a semantic geocatalogue for the spatial data infrastructure (SDI) of the Trentino region, Italy
S-Match: an open source framework for matching lightweight ontologies
No full textAchieving automatic interoperability among systems with diverse data structures and languages expressing different viewpoints is a goal that has been difficult to accomplish. This paper describes S-Match, an open source semantic matching framework that tackles the semantic interoperability problem by transforming several data structures such as business catalogs, web directories, conceptual models and web services descriptions into lightweight ontologies and establishing semantic correspondences between them. The framework is the first open source semantic matching project that includes three different algorithms tailored for specific domains and provides an extensible API for developing new algorithms, including possibility to plug-in specific background knowledge according to the characteristics of each application domain. Published on Semantic Web, IOS Press, 2011 at: http://iospress.metapress.com/content/57661w1u1n712531/?p=7fd96e0bb13646f090c157f2c8e89c37&pi=
Discovering Scientific Communities using Conference Network
No full textThis paper presents an algorithm and a tool for discovering scientific communities. Several approaches have been proposed to discover community structure applying clustering methods over different networks, such as co-authorship and citation networks. However, most existing approaches do not allow for overlapping of communities, which is instead natural when we consider communities of scientists. The approach presented in this paper combines different clustering algorithms for detecting overlapping scientific communities, based on conference publication data. The Community Engine Tool implements the algorithm and was evaluated using the DBLP dataset, which contains information on more than 12 thousand conferences. The results show that using our approach it is possible to automatically produce community structure close to human-defined classification of conferences. The approach is part of a larger research effort aimed at studying how scientific communities are born, evolve, remain healthy or become unhealthy (e.g., self-referential), and eventually vanish