172 research outputs found
Deriving Specifications of Dependable Systems: toward a Method
This paper proposes a method for deriving formal specifications of systems.
To accomplish this task we pass through a non trivial number of steps, concepts
and tools where the first one, the most important, is the concept of method
itself, since we realized that computer science has a proliferation of
languages but very few methods. We also propose the idea of Layered Fault
Tolerant Specification (LFTS) to make the method extensible to dependable
systems. The principle is layering the specification, for the sake of clarity,
in (at least) two different levels, the first one for the normal behavior and
the others (if more than one) for the abnormal. The abnormal behavior is
described in terms of an Error Injector (EI) which represents a model of the
erroneous interference coming from the environment. This structure has been
inspired by the notion of idealized fault tolerant component but the
combination of LFTS and EI using rely guarantee thinking to describe
interference can be considered one of the main contributions of this work. The
progress toward this method and the way to layer specifications has been made
experimenting on the Transportation and the Automotive Case Studies of the
DEPLOY project.Comment: Published in "12th European Workshop on Dependable Computing, EWDC
2009, Toulouse : France (2009)
Issues about the Adoption of Formal Methods for Dependable Composition of Web Services
Web Services provide interoperable mechanisms for describing, locating and
invoking services over the Internet; composition further enables to build
complex services out of simpler ones for complex B2B applications. While
current studies on these topics are mostly focused - from the technical
viewpoint - on standards and protocols, this paper investigates the adoption of
formal methods, especially for composition. We logically classify and analyze
three different (but interconnected) kinds of important issues towards this
goal, namely foundations, verification and extensions. The aim of this work is
to individuate the proper questions on the adoption of formal methods for
dependable composition of Web Services, not necessarily to find the optimal
answers. Nevertheless, we still try to propose some tentative answers based on
our proposal for a composition calculus, which we hope can animate a proper
discussion
On Modelling and Analysis of Dynamic Reconfiguration of Dependable Real-Time Systems
This paper motivates the need for a formalism for the modelling and analysis
of dynamic reconfiguration of dependable real-time systems. We present
requirements that the formalism must meet, and use these to evaluate well
established formalisms and two process algebras that we have been developing,
namely, Webpi and CCSdp. A simple case study is developed to illustrate the
modelling power of these two formalisms. The paper shows how Webpi and CCSdp
represent a significant step forward in modelling adaptive and dependable
real-time systems.Comment: Presented and published at DEPEND 201
The Internet of Hackable Things
The Internet of Things makes possible to connect each everyday object to the
Internet, making computing pervasive like never before. From a security and
privacy perspective, this tsunami of connectivity represents a disaster, which
makes each object remotely hackable. We claim that, in order to tackle this
issue, we need to address a new challenge in security: education
On Methods for the Formal Specification of Fault Tolerant Systems
This paper introduces different views for understanding problems and faults
with the goal of defining a method for the formal specification of systems. The
idea of Layered Fault Tolerant Specification (LFTS) is proposed to make the
method extensible to fault tolerant systems. The principle is layering the
specification in different levels, the first one for the normal behavior and
the others for the abnormal. The abnormal behavior is described in terms of an
Error Injector (EI), which represents a model of the erroneous interference
coming from the environment. This structure has been inspired by the notion of
idealized fault tolerant component but the combination of LFTS and EI using
Rely/Guarantee reasoning to describe their interaction can be considered as a
novel contribution. The progress toward this method and this way to organize
fault tolerant specifications has been made experimenting on case studies and
an example is presented.Comment: Presented and published at DEPEND 201
An LTL Semantics of Business Workflows with Recovery
We describe a business workflow case study with abnormal behavior management
(i.e. recovery) and demonstrate how temporal logics and model checking can
provide a methodology to iteratively revise the design and obtain a correct-by
construction system. To do so we define a formal semantics by giving a
compilation of generic workflow patterns into LTL and we use the bound model
checker Zot to prove specific properties and requirements validity. The working
assumption is that such a lightweight approach would easily fit into processes
that are already in place without the need for a radical change of procedures,
tools and people's attitudes. The complexity of formalisms and invasiveness of
methods have been demonstrated to be one of the major drawback and obstacle for
deployment of formal engineering techniques into mundane projects
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