561 research outputs found

    The xSAP Safety Analysis Platform

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    This paper describes the xSAP safety analysis platform. xSAP provides several model-based safety analysis features for finite- and infinite-state synchronous transition systems. In particular, it supports library-based definition of fault modes, an automatic model extension facility, generation of safety analysis artifacts such as Dynamic Fault Trees (DFTs) and Failure Mode and Effects Analysis (FMEA) tables. Moreover, it supports probabilistic evaluation of Fault Trees, failure propagation analysis using Timed Failure Propagation Graphs (TFPGs), and Common Cause Analysis (CCA). xSAP has been used in several industrial projects as verification back-end, and is currently being evaluated in a joint R&D Project involving FBK and The Boeing Company

    Model Checking Linear Logic Specifications

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    The overall goal of this paper is to investigate the theoretical foundations of algorithmic verification techniques for first order linear logic specifications. The fragment of linear logic we consider in this paper is based on the linear logic programming language called LO enriched with universally quantified goal formulas. Although LO was originally introduced as a theoretical foundation for extensions of logic programming languages, it can also be viewed as a very general language to specify a wide range of infinite-state concurrent systems. Our approach is based on the relation between backward reachability and provability highlighted in our previous work on propositional LO programs. Following this line of research, we define here a general framework for the bottom-up evaluation of first order linear logic specifications. The evaluation procedure is based on an effective fixpoint operator working on a symbolic representation of infinite collections of first order linear logic formulas. The theory of well quasi-orderings can be used to provide sufficient conditions for the termination of the evaluation of non trivial fragments of first order linear logic.Comment: 53 pages, 12 figures "Under consideration for publication in Theory and Practice of Logic Programming

    Assessing Gender Inequality among Italian Regions: The Italian Gender Gap Index

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    This paper aims at exploring and evaluating the geographic distribution of gender inequality across Italian regions. The aim of the analysis is two-fold. First we build a composite indicator of gender inequality at the regional level for Italy by applying the methodology developed by the World Economic Forum for the Global Gender Gap Index. Second, we compute the Italian Gender Gap Index for each region in order to measure the within-country heterogeneity that characterizes Italy. We complete the analysis by presenting the correlation between the Italian Gender Gap Index and relevant socio-economic variables

    Women, medieval commerce, and the education gender gap

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    We investigate the historical determinants of the education gender gap in Italy in the late nineteenth century, immediately following the country’s Unification. We use a comprehensive newly-assembled database including 69 provinces over twenty-year sub-samples covering the 1861- 1901 period. We find robust evidence that female primary school attainment, relative to that of males, is positively associated with the medieval pattern of commerce, along the routes that connected Italian cities among themselves and with the rest of the world. The effect of medieval commerce is particularly strong at the non-compulsory upperprimary level and persists even after controlling for alternative long-term determinants reflecting the geographic, economic, political, and cultural differentiation of medieval Italy. The long-term influence of medieval commerce quickly dissipates after national compulsory primary schooling is imposed at Unification, suggesting that the channel of transmission was the larger provision of education for girls in commercial centers

    Origins and implications of family structure across Italian provinces in historical perspective

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    In this study we review the literature on the origins and implications of family structure in historical perspective with a focus on Italian provinces. Furthermore we present newlycollected data on three of the main features of family structure: female mean age at marriage, the female celibacy rate, and the fraction of illegitimate births. The data are collected at the provincial level for 1871, the year of Italy's political unification. The analysis of the data allows us to confirm and quantify the geographic differentiation in family patterns across the country. We also illustrate the links between family structure and a set of socio-economic outcomes, in the short, medium, and long run

    Probabilistic Model-Based Safety Analysis

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    Model-based safety analysis approaches aim at finding critical failure combinations by analysis of models of the whole system (i.e. software, hardware, failure modes and environment). The advantage of these methods compared to traditional approaches is that the analysis of the whole system gives more precise results. Only few model-based approaches have been applied to answer quantitative questions in safety analysis, often limited to analysis of specific failure propagation models, limited types of failure modes or without system dynamics and behavior, as direct quantitative analysis is uses large amounts of computing resources. New achievements in the domain of (probabilistic) model-checking now allow for overcoming this problem. This paper shows how functional models based on synchronous parallel semantics, which can be used for system design, implementation and qualitative safety analysis, can be directly re-used for (model-based) quantitative safety analysis. Accurate modeling of different types of probabilistic failure occurrence is shown as well as accurate interpretation of the results of the analysis. This allows for reliable and expressive assessment of the safety of a system in early design stages

    Avoiding failure in forest restoration: the importance of genetically diverse and site-matched germplasm

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    A spatiotemporal object-oriented data model for landslides (LOOM)

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    LOOM (landslide object-oriented model) is here presented as a data structure for landslide inventories based on the object-oriented paradigm. It aims at the effective storage, in a single dataset, of the complex spatial and temporal relations between landslides recorded and mapped in an area and at their manipulation. Spatial relations are handled through a hierarchical classification based on topological rules and two levels of aggregation are defined: (i) landslide complexes, grouping spatially connected landslides of the same type, and (ii) landslide systems, merging landslides of any type sharing a spatial connection. For the aggregation procedure, a minimal functional interaction between landslide objects has been defined as a spatial overlap between objects. Temporal characterization of landslides is achieved by assigning to each object an exact date or a time range for its occurrence, integrating both the time frame and the event-based approaches. The sum of spatial integrity and temporal characterization ensures the storage of vertical relations between landslides, so that the superimposition of events can be easily retrieved querying the temporal dataset. The here proposed methodology for landslides inventorying has been tested on selected case studies in the Cilento UNESCO Global Geopark (Italy). We demonstrate that the proposed LOOM model avoids data fragmentation or redundancy and topological inconsistency between the digital data and the real-world features. This application revealed to be powerful for the reconstruction of the gravity-induced deformation history of hillslopes, thus for the prediction of their evolution

    Is there a need for a forest restoration certification scheme?

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    We propose the development of a certification scheme for forest ecosystem restoration that aims for the adoption of protocols and guidelines to ensure the sustained ecological and social value of restored ecosystems. Despite an accumulation of experience on ecosystem restoration over the past decades, it is still common to measure the success of restoration mainly in terms of number of seedlings planted or their survival in the short term. A strong focus on planting targets may divert attention from the actual objectives: establish self-sustaining forested ecosystems that provide livelihood or other ecosystem service benefits to local people. Two important determinants of short and long term success, which often do not receive sufficient attention, are matching the right seed source to the planting site conditions and ensuring that restored populations of trees have sufficient genetic variability to be self-sustaining. Because of the enormous scale of land degradation and the funds being pledged to tackle it, standardized measures of success are of increasing importance. Restoration success needs to be evaluated in a holistic way by restoration practitioners, government institutions, civil society organizations, private sector and, importantly, funding agencies. Much is known about how to restore ecosystems in different regions and under different conditions, however currently there is no consensus on what success looks like or what the minimum criteria should be for monitoring and documenting success. Success can be achieved by following well defined practices and protocols (eg by ensuring high diversity both at species and genes levels, number of mother trees for the collection of reproductive material, provenance, etc) during the various phases of the restoration process. We make a case for the development of a certification system to support long term value of restored populations for global application
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