565 research outputs found
The xSAP Safety Analysis Platform
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
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
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
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
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
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
A spatiotemporal object-oriented data model for landslides (LOOM)
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?
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
Regional networking for the conservation and management of forest genetic resources: priorities and experiences from around the world
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