1,138 research outputs found

    A Terminating Evaluation-Driven Variant of G3i

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    We present Gbu, a terminating variant of the sequent calculus G3i for intuitionistic propositional logic. Gbu modifies G3i by annotating the sequents so to distinguish rule applications into two phases: an unblocked phase where any rule can be backward applied, and a blocked phase where only right rules can be used. Derivations of Gbu have a trivial translation into G3i. Rules for right implication exploit an evaluation relation, defined on sequents; this is the key tool to avoid the generation of branches of infinite length in proof-search. To prove the completeness of Gbu, we introduce a refutation calculus Rbu for unprovability dual to Gbu. We provide a proof-search procedure that, given a sequent as input, returns either a Rbu-derivation or a Gbu-derivation of it

    A webgis for the knowledge and conservation of the historical buildings in Sardinia (Italy)

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    The presented work is part of the research project, titled "Tecniche murarie tradizionali: conoscenza per la conservazione ed il miglioramento prestazionale" (Traditional building techniques: from knowledge to conservation and performance improvement). This research project has the purpose of studying the building techniques of the 13th- 18thcenturies in the Sardinia Region (Italy) for their knowledge, conservation, and promotion. The end purpose of the entire study is to improve the performance of the examined structures. In particular, the task of the authors within the research project was to build a WebGIS to manage the data collected during the examination and study phases. This infrastructure was entirely built using Open Source software. The work consisted of designing a database built in PostgreSQL and its spatial extension PostGIS, which allows storing and managing feature geometries and spatial data. The data input is performed via a form built in HTML and PHP. The HTML part is based on Bootstrap, an open tools library for websites and web applications. The implementation of this template used both PHP and Javascript code. The PHP code manages the reading and writing of data to the database, using embedded SQL queries. The database is published on the Internet as a WebGIS built using the Leaflet Javascript open libraries, which allows creating map sites with background maps and navigation, input and query tools. This too uses an interaction of HTML, Javascript, PHP and SQL code. The Database can be accessed in QGIS via a PostgreSQL connection. As of today, we surveyed and archived more than 300 buildings, belonging to three main macro categories: fortification architectures, religious architectures, residential architectures

    A WEBGIS for the knowledge and conservation of the historical wall structures of the 13th–18th centuries

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    The presented work is part of the research project, titled "Tecniche murarie tradizionali: conoscenza per la conservazione ed il miglioramento prestazionale" (Traditional building techniques: from knowledge to conservation and performance improvement), with the purpose of studying the building techniques of the 13th–18th centuries in the Sardinia Region (Italy) for their knowledge, conservation, and promotion. The end purpose of the entire study is to improve the performance of the examined structures. In particular, the task of the authors within the research project was to build a WebGIS to manage the data collected during the examination and study phases. This infrastructure was entirely built using Open Source software. The work consisted of designing a database built in PostgreSQL and its spatial extension PostGIS, which allows to store and manage feature geometries and spatial data. The data input is performed via a form built in HTML and PHP. The HTML part is based on Bootstrap, an open tools library for websites and web applications. The implementation of this template used both PHP and Javascript code. The PHP code manages the reading and writing of data to the database, using embedded SQL queries. As of today, we surveyed and archived more than 300 buildings, belonging to three main macro categories: fortification architectures, religious architectures, residential architectures. The masonry samples investigated in relation to the construction techniques are more than 150. The database is published on the Internet as a WebGIS built using the Leaflet Javascript open libraries, which allows creating map sites with background maps and navigation, input and query tools. This too uses an interaction of HTML, Javascript, PHP and SQL code

    Sequent Calculus in the Topos of Trees

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    Nakano's "later" modality, inspired by G\"{o}del-L\"{o}b provability logic, has been applied in type systems and program logics to capture guarded recursion. Birkedal et al modelled this modality via the internal logic of the topos of trees. We show that the semantics of the propositional fragment of this logic can be given by linear converse-well-founded intuitionistic Kripke frames, so this logic is a marriage of the intuitionistic modal logic KM and the intermediate logic LC. We therefore call this logic KMlin\mathrm{KM}_{\mathrm{lin}}. We give a sound and cut-free complete sequent calculus for KMlin\mathrm{KM}_{\mathrm{lin}} via a strategy that decomposes implication into its static and irreflexive components. Our calculus provides deterministic and terminating backward proof-search, yields decidability of the logic and the coNP-completeness of its validity problem. Our calculus and decision procedure can be restricted to drop linearity and hence capture KM.Comment: Extended version, with full proof details, of a paper accepted to FoSSaCS 2015 (this version edited to fix some minor typos

    Vertical ridge augmentation with Ti-reinforced dense polytetrafluoroethylene (d-PTFE) membranes or Ti-meshes and collagen membranes: 3-year results of a randomized clinical trial

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    BackgroundThe present study aimed to evaluate hard and soft tissue parameters around implants placed in augmented posterior mandible, comparing Ti-reinforced d-PTFE membranes with Ti-meshes covered with collagen membranes, after 3 years of follow-up. Materials and MethodsForty eligible patients were randomly assigned to group A (Ti-reinforced d-PTFE membrane) or group B (mesh covered with collagen membrane) for vertical ridge augmentation (VRA) and simultaneous implants. Implants were evaluated using specific peri-implant parameters for bone and soft tissues: probing pocket depth (PPD), modified plaque index (mPI), bleeding on probing (BoP), modified gingival index (mGI), thickness of keratinized tissue (tKT), width of keratinized tissue (wKT), fornix depth (FD), peri-implant bone level (PBL), interproximal bone peaks (IBP), marginal bone loss (MBL), interproximal bone loss (IBL). ResultsA total of 28 patients with 79 implants were evaluated after 3 years of follow-up. The mean value of MBL was 0.70 mm (group A = 0.73 mm; group B = 0.71 mm), while mean IBL was 0.54 mm (group A = 0.64 mm; group B = 0.40 mm). The treatment with meshes resulted not inferior to PTFE and their clinical results appeared similar. A strong correlation between PBL and IBP was confirmed. Both study groups showed an increase of tKT and wKT values. ConclusionIn the posterior mandible, VRA using both techniques provides stable PBLs up to 3 years. A correct soft tissue management and a strict professional oral hygiene protocol play a crucial role on peri-implant health over time

    BCDL : Basic Constructive Description Logic

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    In this paper we present BCDL, a description logic based on information terms semantics, which allows a constructive interpretation of ALC formulas. In the paper we describe the information terms semantics, we define a natural deduction calculus for BCDL and we show it is sound and complete. As a first application of proof-theoretical properties of the calculus, we show how it fulfills the proofs-as-programs paradigm. Finally, we discuss the role of generators, the main element distinguishing our formalisation from the usual ones

    Simplification rules for intuitionistic propositional tableaux

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    The implementation of a logic requires, besides the definition of a calculus and a decision procedure, the development of techniques to reduce the search space. In this article we introduce some simplification rules for Intuitionistic propositional logic that try to replace a formula with an equi-satisfiable \u201csimpler\u201d one with the aim to reduce the search space. Our results are proved via semantical techniques based on Kripke models. We also provide an empirical evaluation of their impact on implementations

    A secondary semantics for second order intuitionistic propositional logic

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    In this paper we propose a Kripke-style semantics for second order intuitionistic propositional logic and we provide a semantical proof of the disjunction and the explicit definability property. Moreover, we provide a tableau calculus which is sound and complete with respect to such a semantics
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