107 research outputs found

    Towards an Ontological Modelling of Preference Relations

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    Preference relations are intensively studied in Economics, but they are also approached in AI, Knowledge Representation, and Conceptual Modelling, as they provide a key concept in a variety of domains of application. In this paper, we propose an ontological foundation of preference relations to formalise their essential aspects across domains. Firstly, we shall discuss what is the ontological status of the relata of a preference relation. Secondly, we investigate the place of preference relations within a rich taxonomy of relations (e.g. we ask whether they are internal or external, essential or contingent, descriptive or nondescriptive relations). Finally, we provide an ontological modelling of preference relation as a module of a foundational (or upper) ontology (viz. OntoUML). The aim of this paper is to provide a sharable foundational theory of preference relation that foster interoperability across the heterogeneous domains of application of preference relations

    Seismic Assessment and Strengthening Interventions of Atop Single-Block Rocking Elements in Monumental Buildings: the Case Study of the San Felice sul Panaro Fortress

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    The paper describes the seismic assessment of the San Felice sul Panaro Fortress (Italy), focusing the attention on the activation of the out-of-plane response of the North walkway, characterized by the presence of an apparatus of merlons which highlighted a significant damage after the Emilia earthquake (2012). Nonlinear kinematic analyses have been performed, referring to a macro-block model and considering both the original configuration and two different possible strengthened strategies. For the definition of the seismic input in terms of floor spectra, the analyses also benefitted from the results obtained for the global response through a detailed 3D model of the whole fortress. The results were coherent with the observed damage after the seismic event, highlighting in this way the reliability of the adopted modelling strategies and analysis method, and allowed to outline possible strengthening solutions targeted to minimize the impact on the monument and guarantee its preservation

    Damage and vulnerability analysis of URM churches after the Canterbury earthquake sequence 2010-2011

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    The Canterbury earthquake sequence, in 2010-2011, has highlighted once again the vulnerability ofmonumental structures, in particular churches, and the importance of reducing their risk from an economic, cultural and social point of view. Within this context, detailed analysis is reported of the earthquake-induced damage to a stock of 48 unreinforcedmasonry churches located in the Canterbury Region and the vulnerability analysis of a wider stock of 293 churches located all around New Zealand. New tools were developed forthe assessmentof New Zealand churches. The computation of a new damage grade isproposed, assessed as a proper combination of the damage level to each macroelement, as a step towards the definition of a New Zealand specific damage survey form. Several vulnerability indicators were selected, which are related to easily detectable structural details and geometric dimensions. The collection of such data for the larger set of churches (293) constitutes a useful basis for evaluating the potential impact of future seismic event

    Fragility functions for tall URM buildings around early 20th century in Lisbon. Part 1: Methodology and application at building level

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    The article proposes a procedure for the derivation of fragility functions for unreinforced masonry buildings considering the in-plane and out-of-plane response. Different approaches are considered for the generation of the corresponding fragility functions and for the evaluation of the propagation of uncertainties. The contributions for the dispersion of the fragility functions account for the variability in the definition of the capacity, the aleatory uncertainty in the definition of the seismic demand and the aleatory uncertainty in the definition of the modified/floor response spectrum, when the local mechanisms are located in the upper level of the building. In the end, the individual fragility curves are properly combined in order to define a single fragility curve for the class of buildings. As a case study, the procedure is applied to the assessment of one of the most vulnerable unreinforced masonry buildings constructed in the early 20th century in Lisbon, considering a typical prototype building with five storeys high. Results for a seismic event, as defined in the earthquake-resistant code for Lisbon, indicate that the typical building has about 50% probability of having heavy damage and about 30% probability of collapse.The first author would like to acknowledge the financial support of Fundação para a CiĂȘncia e a Tecnologia (FCT, MinistĂ©rio da Educação e CiĂȘncia, Portugal) through the scholarship PD/BD/106076/2015 through the FCT Doctoral Program: Analysis and Mitigation of Risks in Infrastructures, INFRARISK- (http://infrarisk.tecnico.ulisboa.pt)

    Repairing Socially Aggregated Ontologies Using Axiom Weakening

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    Ontologies represent principled, formalised descriptions of agents’ conceptualisations of a domain. For a community of agents, these descriptions may differ among agents. We propose an aggregative view of the integration of ontologies based on Judgement Aggregation (JA). Agents may vote on statements of the ontologies, and we aim at constructing a collective, integrated ontology, that reflects the individual conceptualisations as much as possible. As several results in JA show, many attractive and widely used aggregation procedures are prone to return inconsistent collective ontologies. We propose to solve the possible inconsistencies in the collective ontology by applying suitable weakenings of axioms that cause inconsistencies

    A methodology for the seismic risk mitigation based on mechanical models: the case of reinforced concrete school buildings in Genoa (Italy)

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    Recent earthquakes have highlighted the potential seismic vulnerability of existing reinforced concrete buildings; not only in case of residential buildings but also strategic structures, such as schools or hospitals. Thus, a reliable vulnerability assessment at large scale becomes crucial in particular for public institutions to optimize the criteria to identify the priorities of intervention (priority lists) in order to better allocate the limited economic resources. Among the different approaches proposed in literature, the use of mechanical models seems particularly suitable to this aim. These models, being based on a limited number of geometrical and mechanical parameters, allow to describe the inelastic response of buildings by capacity curves. In the paper the attention is focused on the DBV-concrete model proposed in Lagomarsino et al. (2010) based on the displacement-based approach. It has been applied on the case of 55 schools of Genoa Province (North Italy). Results are compared to those provided by on observational vulnerability model in order to combine these different approaches for defining proper priority list
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