11,556 research outputs found
MeGARA: Menu-based Game Abstraction and Abstraction Refinement of Markov Automata
Markov automata combine continuous time, probabilistic transitions, and
nondeterminism in a single model. They represent an important and powerful way
to model a wide range of complex real-life systems. However, such models tend
to be large and difficult to handle, making abstraction and abstraction
refinement necessary. In this paper we present an abstraction and abstraction
refinement technique for Markov automata, based on the game-based and
menu-based abstraction of probabilistic automata. First experiments show that a
significant reduction in size is possible using abstraction.Comment: In Proceedings QAPL 2014, arXiv:1406.156
Possibilistic Information Flow Control for Workflow Management Systems
In workflows and business processes, there are often security requirements on
both the data, i.e. confidentiality and integrity, and the process, e.g.
separation of duty. Graphical notations exist for specifying both workflows and
associated security requirements. We present an approach for formally verifying
that a workflow satisfies such security requirements. For this purpose, we
define the semantics of a workflow as a state-event system and formalise
security properties in a trace-based way, i.e. on an abstract level without
depending on details of enforcement mechanisms such as Role-Based Access
Control (RBAC). This formal model then allows us to build upon well-known
verification techniques for information flow control. We describe how a
compositional verification methodology for possibilistic information flow can
be adapted to verify that a specification of a distributed workflow management
system satisfies security requirements on both data and processes.Comment: In Proceedings GraMSec 2014, arXiv:1404.163
Reconciling a component and process view
In many cases we need to represent on the same abstraction level not only
system components but also processes within the system, and if for both
representation different frameworks are used, the system model becomes hard to
read and to understand. We suggest a solution how to cover this gap and to
reconcile component and process views on system representation: a formal
framework that gives the advantage of solving design problems for large-scale
component systems.Comment: Preprint, 7th International Workshop on Modeling in Software
Engineering (MiSE) at ICSE 201
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