221 research outputs found
Quantitative Assurance and Synthesis of Controllers from Activity Diagrams
Probabilistic model checking is a widely used formal verification technique
to automatically verify qualitative and quantitative properties for
probabilistic models. However, capturing such systems, writing corresponding
properties, and verifying them require domain knowledge. This makes it not
accessible for researchers and engineers who may not have the required
knowledge. Previous studies have extended UML activity diagrams (ADs),
developed transformations, and implemented accompanying tools for automation.
The research, however, is incomprehensive and not fully open, which makes it
hard to be evaluated, extended, adapted, and accessed. In this paper, we
propose a comprehensive verification framework for ADs, including a new profile
for probability, time, and quality annotations, a semantics interpretation of
ADs in three Markov models, and a set of transformation rules from activity
diagrams to the PRISM language, supported by PRISM and Storm. Most importantly,
we developed algorithms for transformation and implemented them in a tool,
called QASCAD, using model-based techniques, for fully automated verification.
We evaluated one case study where multiple robots are used for delivery in a
hospital and further evaluated six other examples from the literature. With all
these together, this work makes noteworthy contributions to the verification of
ADs by improving evaluation, extensibility, adaptability, and accessibility.Comment: 43 pages, 29 figures, 5 tables, submitted to Journal of Systems and
Software (JSS
Verification and validation of UML and SysML based systems engineering design models
In this thesis, we address the issue of model-based verification and validation of systems engineering design models expressed using UML/SysML. The main objectives are to assess the design from its structural and behavioral perspectives and to enable a qualitative as well as a quantitative appraisal of its conformance with respect to its requirements and a set of desired properties. To this end, we elaborate a heretofore unattempted unified approach composed of three well-established techniques that are model-checking, static analysis, and software engineering metrics. These techniques are synergistically combined so that they yield a comprehensive and enhanced assessment. Furthermore, we propose to extend this approach with performance analysis and probabilistic assessment of SysML activity diagrams. Thus, we devise an algorithm that systematically maps these diagrams into their corresponding probabilistic models encoded using the specification language of the probabilistic symbolic model-checker PRISM. Moreover, we define a first of its kind probabilistic calculus, namely activity calculus, dedicated to capture the essence of SysML activity diagrams and its underlying operational semantics in terms of Markov decision processes. Furthermore, we propose a formal syntax and operational semantics for the input language of PRISM. Finally, we mathematically prove the soundness of our translation algorithm with respect to the devised operational semantics using a simulation preorder defined upon Markov decision processes
FLACOS’08 Workshop proceedings
The 2nd Workshop on Formal Languages and Analysis of Contract-Oriented Software (FLACOS’08) is held in Malta. The aim of the workshop is to bring together researchers and practitioners working on language-based solutions to contract-oriented software development. The workshop is partially funded by the Nordunet3 project “COSoDIS” (Contract-Oriented Software Development for Internet Services) and it attracted 25 participants. The program consists of 4 regular papers and 10 invited participant presentations
Modeling Time in Computing: A Taxonomy and a Comparative Survey
The increasing relevance of areas such as real-time and embedded systems,
pervasive computing, hybrid systems control, and biological and social systems
modeling is bringing a growing attention to the temporal aspects of computing,
not only in the computer science domain, but also in more traditional fields of
engineering.
This article surveys various approaches to the formal modeling and analysis
of the temporal features of computer-based systems, with a level of detail that
is suitable also for non-specialists. In doing so, it provides a unifying
framework, rather than just a comprehensive list of formalisms.
The paper first lays out some key dimensions along which the various
formalisms can be evaluated and compared. Then, a significant sample of
formalisms for time modeling in computing are presented and discussed according
to these dimensions. The adopted perspective is, to some extent, historical,
going from "traditional" models and formalisms to more modern ones.Comment: More typos fixe
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