102 research outputs found
Viewpoint Development of Stochastic Hybrid Systems
Nowadays, due to the explosive spreading of networked and highly distributed systems, mastering system complexity becomes a critical issue. Two development and verification paradigms have become more popular: viewpoints and randomisation. The viewpoints offer large freedom and introduce concurrency and compositionality in the development process. Randomisation is now a traditional method for reducing complexity (comparing with deterministic models) and it offers finer analytical analysis tools (quantification over non-determinism, multi-valued logics, etc). In this paper, we propose a combination of these two paradigms introducing a viewpoint methodology for systems with stochastic behaviours
Formal Methods in Conformance Testing: A Probabilistic Refinement
This paper refines the framework of āFormal Methods in Conformance Testingā by introducing
probabilities for concepts which have a stochastic nature. Test execution is refined into test
runs, where each test run is considered as a stochastic process that returns a possible observa-
tion with a certain probability. This implies that not every possible observation that could be
made, will actually be made. The development process of an implementation from a specifica-
tion is also viewed as a stochastic process that may result in a specific implementation with a
certain probability. Together with a weight assignment on implementations this introduces a
valuation measure on implementations. The test run probabilities and the valuation measures
are integrated in generalized definitions of soundness and exhaustiveness, which can be used
to compare test suites with respect to their ability to accept correct, and to reject erroneous
implementations
Monadic Maps and Folds for Arbitrary Datatypes
Each datatype constructor comes equiped not only with a so-called map and fold (<i>catamorphism</i>), as is widely known, but, under some condition, also with a kind of map and fold that are related to an arbitrary given monad.\ud
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This result follows from the preservation of initiality under lifting from the category of algebras in a given category to a certain other category of algebras in the Kleisli category related to the monad
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