1,721,203 research outputs found
Combining Deduction and Model Checking into Tableaux and Algorithms for Converse-PDL
No full textAbstractThis paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse based on a combination of different techniques such as prefixed tableaux for modal logics and model checkers for μ-calculus. We prove the correctness and completeness of the calculus and illustrate its features. We also discuss the transformation of the tableaux method (naively NEXPTIME) into an EXPTIME algorithm
Tableaux and Algorithms for Propositional Dynamic Logic with Converse
No full textThis paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse based on a combination of different techniques such as prefixed tableaux for modal logics and model checkers for mu-calculus. We prove the correctness and completeness of the calculus and illustrate its features. We also discuss the transformation of the tableaux method (naively NEXPTIME) into an EXPTIME algorithm
Fire Detection using Wireless Sensor Networks: An Approach Based on Statistical Data Modeling
No full textThe aim of this work is to propose an innovative architecture for fire detection, using a Wireless Sensor Network. This scheme is based on the statistical modeling of the Angstrom Index. So far, such an index has been applied in outdoor environments. The results obtained by our analysis have extended its validity also to indoor scenarios. A key strength of our system is that each sensor node models the collected measures of the index, in order to transmit, in normal conditions, only the parameters of such a model, thus saving energy. To test the effectiveness of our fire detection system, we have simulated a fire in a building using the Fire Dynamics Simulator. Results have shown that our proposed system is able to reach a good tradeoff between energy consumption and detection delay, in several operative condition
A SAT-based decision procedure for ALC
No full textThe goal of this paper is to describe and thoroughly test a decision procedure, called Ksat, checking satisfiability in the terminological logic ALC. Ksat is said to be SAT-based as it is defined in terms of a decision procedure for propositional satisfiability (SAT). The tests are performed comparing Ksat with, among other procedures, Kris, a state-of-the-art tableau-based implementation of a decision procedure for ALC. Ksat outperforms Kris of orders of magnitude. Furthermore, the empirical results highlight an intrinsic weakeness that tableau-based decision procedures have with respect to SAT-based decision procedures. Franz Baader, Marco Cadoli, Enrico Franconi, Enrico Giunchiglia, Fabio Massacci and Bernhard Nebel have given very useful feedback. Fabio Massacci has suggested testing the Halpern & Moses formulas. Marco Roveri has given technical assistance in the testing phase. All the members of the Mechanized Reasoning Group in Genoa have put up with many weeks of CPU-time back..
Planning attacks to security protocols: Case studies in logic programming
Full text linkFormal verification of security protocols has become a key issue in computer security. Yet, it has proven to be a hard task often error prone and discouraging for non-experts in formal methods. In this paper we show how security protocols can be specified and verified efficiently and effectively by embedding reasoning about actions into a logic programming language. In a nutshell, we view a protocol trace as a plan to achieve a goal, so that protocol attacks are plans achieving goals that correspond to security violations. Building on results from logic programming and planning, we map the existence of an attack to a protocol into the existence of a model for the protocol specification that satisfies the specification of an attack. To streamline such way of modeling security protocols, we use a description language AL(SP) which makes it possible to describe protocols with declarative ease and to search for attacks by relying on efficient model finders (e.g. the smodels systems by Niemela and his group). This paper shows how to use AL(SP) for modeling two significant case studies in protocol verification: the classical Needham-Schroeder public-key protocol, and Aziz-Diffie Key agreement protocol for mobile communication
Security in the Firefox OS and Tizen Mobile Platforms
No full textEmerging mobile platforms Firefox OS and Tizen are learning from Android's security successes and trying to avoid its limitations. Although these platforms offer largely novel solutions, they can still learn from one another. The Web extra at http://youtu.be/yZjVsWz_DAY is a video discussion in which authors Fabio Massacci and Yury Zhauniarovich discuss Android's successes and limitations and what developers can learn from them
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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