Using a Machine Learning Approach to Implement and Evaluate Product Line Features

Bike-sharing systems are a means of smart transportation in urban environments with the benefit of a positive impact on urban mobility. In this paper we are interested in studying and modeling the behavior of features that permit the end user to access, with her/his web browser, the status of the Bike-Sharing system. In particular, we address features able to make a prediction on the system state. We propose to use a machine learning approach to analyze usage patterns and learn computational models of such features from logs of system usage. On the one hand, machine learning methodologies provide a powerful and general means to implement a wide choice of predictive features. On the other hand, trained machine learning models are provided with a measure of predictive performance that can be used as a metric to assess the cost-performance trade-off of the feature. This provides a principled way to assess the runtime behavior of different components before putting them into operation.Comment: In Proceedings WWV 2015, arXiv:1508.0338

Logical Specification and Analysis of Fault Tolerant Systems through Partial Model Checking

This paper presents a framework for a logical characterisation of fault tolerance and its formal analysis based on partial model checking techniques. The framework requires a fault tolerant system to be modelled using a formal calculus, here the CCS process algebra. To this aim we propose a uniform modelling scheme in which to specify a formal model of the system, its failing behaviour and possibly its fault-recovering procedures. Once a formal model is provided into our scheme, fault tolerance - with respect to a given property - can be formalized as an equational µ-calculus formula. This formula expresses in a logic formalism, all the fault scenarios satisfying that fault tolerance property. Such a characterisation understands the analysis of fault tolerance as a form of analysis of open systems and thank to partial model checking strategies, it can be made independent on any particular fault assumption. Moreover this logical characterisation makes possible the fault-tolerance verification problem be expressed as a general µ-calculus validation problem, for solving which many theorem proof techniques and tools are available. We present several analysis methods showing the flexibility of our approach

Analisi dell'assorbimento energetico in velivoli All-Electric: sviluppo di modelli di attuatori elettromeccanici per comandi di volo

La presente tesi si inserisce nell'ambito del progetto europeo "Clean Sky" che coinvolge anche il Dipartimento di Ingegneria Aerospaziale di Pisa. L'obiettivo è lo sviluppo di modelli di attuatori elettromeccanici in ambiente Simulink e AMESim al fine di studiarne gli assorbimenti di potenza elettrica

Enhancing Test Coverage by Back-tracing Model-checker Counterexamples

AbstractThe automatic detection of unreachable coverage goals and generation of tests for "corner-case" scenarios is crucial to make testing and simulation based verification more effective. In this paper we address the problem of coverability analysis and test case generation in modular and component based systems. We propose a technique that, given an uncovered branch in a component, either establishes that the branch cannot be covered or produces a test case at the system level which covers the branch. The technique is based on the use of counterexamples returned by model checkers, and exploits compositionality to cope with large state spaces typical of real applications

Applying generalized non deducibility on compositions (GNDC) approach in dependability

This paper presents a framework where dependable systems can be uniformly modeled and dependable properties analyzed within the Generalized Non Deducibility on Compositions (GNDC), a scheme that has been profitably used in definition and analysis of security properties. Precisely, our framework requires a systems to be modelled using a formal calculus, here the CCS process algebra, where both the failing behaviour of the system and the related fault-recovering procedures are also explicitly described. An environment able to inject any fault in the system is then defined as a separated component. The parallel composition between the system and the environment represents our scenario of analysis, where some fault tolerance property (e.g., fail stop, safe and silent) are studied as instances of GNDC properties. By using different instances of GNDC we are able to argue about the availability of effective methodologies of analysis, and on the possibility of applying compositional techniques