147 research outputs found
Causality and Temporal Dependencies in the Design of Fault Management Systems
Reasoning about causes and effects naturally arises in the engineering of
safety-critical systems. A classical example is Fault Tree Analysis, a
deductive technique used for system safety assessment, whereby an undesired
state is reduced to the set of its immediate causes. The design of fault
management systems also requires reasoning on causality relationships. In
particular, a fail-operational system needs to ensure timely detection and
identification of faults, i.e. recognize the occurrence of run-time faults
through their observable effects on the system. Even more complex scenarios
arise when multiple faults are involved and may interact in subtle ways.
In this work, we propose a formal approach to fault management for complex
systems. We first introduce the notions of fault tree and minimal cut sets. We
then present a formal framework for the specification and analysis of
diagnosability, and for the design of fault detection and identification (FDI)
components. Finally, we review recent advances in fault propagation analysis,
based on the Timed Failure Propagation Graphs (TFPG) formalism.Comment: In Proceedings CREST 2017, arXiv:1710.0277
An Effective Fixpoint Semantics for Linear Logic Programs
In this paper we investigate the theoretical foundation of a new bottom-up
semantics for linear logic programs, and more precisely for the fragment of
LinLog that consists of the language LO enriched with the constant 1. We use
constraints to symbolically and finitely represent possibly infinite
collections of provable goals. We define a fixpoint semantics based on a new
operator in the style of Tp working over constraints. An application of the
fixpoint operator can be computed algorithmically. As sufficient conditions for
termination, we show that the fixpoint computation is guaranteed to converge
for propositional LO. To our knowledge, this is the first attempt to define an
effective fixpoint semantics for linear logic programs. As an application of
our framework, we also present a formal investigation of the relations between
LO and Disjunctive Logic Programming. Using an approach based on abstract
interpretation, we show that DLP fixpoint semantics can be viewed as an
abstraction of our semantics for LO. We prove that the resulting abstraction is
correct and complete for an interesting class of LO programs encoding Petri
Nets.Comment: 39 pages, 5 figures. To appear in Theory and Practice of Logic
Programmin
Basin scale assessment of landslides geomorphological setting by advanced InSAR analysis
An extensive investigation of more than 90 landslides affecting a small river basin in Central
Italy was performed by combining field surveys and remote sensing techniques. We thus defined the
geomorphological setting of slope instability processes. Basic information, such as landslides mapping
and landslides type definition, have been acquired thanks to geomorphological field investigations
and multi-temporal aerial photos interpretation, while satellite SAR archive data (acquired by ERS
and Envisat from 1992 to 2010) have been analyzed by means of A-DInSAR (Advanced Differential
Interferometric Synthetic Aperture Radar) techniques to evaluate landslides past displacements
patterns. Multi-temporal assessment of landslides state of activity has been performed basing
on geomorphological evidence criteria and past ground displacement measurements obtained by
A-DInSAR. This step has been performed by means of an activity matrix derived from information
achieved thanks to double orbital geometry. Thanks to this approach we also achieved more detailed
knowledge about the landslides kinematics in time and space
Symbolic Model Checking and Safety Assessment of Altarica models
Altarica is a language used to describe critical systems. In this paper we present a novel approach to the analysis of Altarica models, based on a translation into an extended version of NuSMV. This approach opens up the possibility to carry out functional verification and safety assessment with symbolic techniques. An experimental evaluation on a set of industrial case studies demonstrates the advantages of the approach over currently available tools.
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
Geological and geomorphological analysis of a complex landslides system: the case of San Martino sulla Marruccina (Abruzzo, Central Italy)
This work deals with the landslides affecting the area surrounding the village of San Martino sulla Marrucina and involving the neighboring municipalities of Casacanditella and Filetto. The geological and geomorphological settings of this area are being discussed. The enclosed maps have been realized following a multidisciplinary approach, based on morphometric, geological, and geomorphological analyses and supported by air-photo interpretation, dendrochronology, and satellite SAR interferometry (InSAR). The map is organized in four sections: orography (on the upper part), geological map (on the upper right part), main geomorphological map (in the central left part, 1:7,500 scale), and multitemporal analysis (in the lower part). The aforementioned multi-temporal assessment of landslides was performed according to the geomorphological evidence-based criteria and the past ground displacement measurements were obtained by dendrochronology and InSAR. The aim of the study is to understand the evolution in time and space of this landslide area, focusing on the corresponding kinematics
EMSO ERIC: A challenging infrastructure to monitor Essential Ocean Variables (EOVs) across European Seas
The European Multidisciplinary Seafoor and water Column Observatory (EMSO, www.emso.eu) is a distributed research infrastructure (RI), composed of fxed-point deep-sea observatories and shallow water test sites at strategic environmental locations from the southern entrance of the Arctic Ocean all the way through the North Atlantic through the Mediterranean to the Black Sea. Working as a single powerful system, it is a valuable new tool for researchers and engineers looking for long time series of high-quality and high-resolution data to study and continuously monitor complex processes interactions among the geosphere, biosphere, hydrosphere and atmosphere, as well as to test, validate and demonstrate new marine technologies.Peer Reviewe
EMSO ERIC: A challenging infrastructure to monitor Essential Ocean Variables (EOVs) across European Seas
Special issue 9th MARTECH: International Workshop on Marine Technology: 16-18 June 2021, Vigo, Spain.-- 2 pages, 1 figureThe European Multidisciplinary Seafoor and water Column Observatory (EMSO, www.emso.eu) is a distributed research infrastructure (RI), composed of fxed-point deep-sea observatories and shallow water test sites at strategic environmental locations from the southern entrance of the Arctic Ocean all the way through the North Atlantic through the Mediterranean to the Black Sea. Working as a single powerful system, it is a valuable new tool for researchers and engineers looking for long time series of high-quality and high-resolution data to study and continuously monitor complex processes interactions among the geosphere, biosphere, hydrosphere and atmosphere, as well as to test, validate and demonstrate new marine technologiesPeer reviewe
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