1,615 research outputs found
A probabilistic extension of UML statecharts: specification and verification
This paper is the extended technical report that corresponds to a published paper [14]. This paper introduces means to specify system randomness within UML statecharts, and to verify probabilistic temporal properties over such enhanced statecharts which we call probabilistic UML statecharts. To achieve this, we develop a general recipe to extend a statechart semantics with discrete probability distributions, resulting in Markov decision processes as semantic models. We apply this recipe to the requirements-level UML semantics of [8]. Properties of interest for probabilistic statecharts are expressed in PCTL, a probabilistic variant of CTL for processes that exhibit both non-determinism and probabilities. Verification is performed using the model checker Prism. A model checking example shows the feasibility of the suggested approach
Extensions of statecharts : with probability, time, and stochastic timing
Statecharts are a graphical language to describe the behaviour of a system. For example, in the UML, a statechart can be used to describe the behaviour of an object. Model checking is a method to verify automatically whether a system satisfies some desired property.\ud
The goal of this thesis is: To use statecharts to render model checking more widely usable.\ud
We show this in two respects: For real-time statecharts, we provide a property language that fits nicely with the features of statecharts. For probabilistic model checking, we provide an extension of statecharts as input language
Auto-coding UML statecharts for flight software
Statecharts have been used as a means to
communicate behaviors in a precise manner between
system engineers and software engineers. Handtranslating
a statechart to code, as done on some
previous space missions, introduces the possibility of
errors in the transformation from chart to code. To
improve auto-coding, we have developed a process
that generates flight code from UML statecharts. Our
process is being used for the flight software on the
Space Interferometer Mission (SIM)
A Holistic Approach in Embedded System Development
We present pState, a tool for developing "complex" embedded systems by
integrating validation into the design process. The goal is to reduce
validation time. To this end, qualitative and quantitative properties are
specified in system models expressed as pCharts, an extended version of
hierarchical state machines. These properties are specified in an intuitive way
such that they can be written by engineers who are domain experts, without
needing to be familiar with temporal logic. From the system model, executable
code that preserves the verified properties is generated. The design is
documented on the model and the documentation is passed as comments into the
generated code. On the series of examples we illustrate how models and
properties are specified using pState.Comment: In Proceedings F-IDE 2015, arXiv:1508.0338
Dependability checking with StoCharts: Is train radio reliable enough for trains?
Performance, dependability and quality of service (QoS) are prime aspects of the UML modelling domain. To capture these aspects effectively in the design phase, we have recently proposed STOCHARTS, a conservative extension of UML statechart diagrams. In this paper, we apply the STOCHART formalism to a safety critical design problem. We model a part of the European Train Control System specification, focusing on the risks of wireless communication failures in future high-speed cross-European trains. Stochastic model checking with the model checker PROVER enables us to derive constraints under which the central quality requirements are satisfied by the STOCHART model. The paper illustrates the flexibility and maturity of STOCHARTS to model real problems in safety critical system design
Timing diagrams add Requirements Engineering capability to Event-B Formal Development
Event-B is a language for the formal development of reactive systems. At present the RODIN toolkit [15] for Event-B is used for modeling requirements, specifying refinements and doing verification. In order to extend graphical requirements modeling capability into the real-time domain, where timing constraints are essential, we propose a Timing diagram (TD) [13] notation for Event-B. The UML 2.0 based notation provides an intuitive graphical specification capability for timing constraints and causal dependencies between system events. A translation scheme to Event-B is proposed and presented. Support for model refinement is provided. A partial case study is used to demonstrate the translation in practice
Statechart Slicing
The paper discusses how to reduce a statechart model by slicing. We start with the discussion of control dependencies and data dependencies in statecharts. The and-or dependence graph is introduced to represent control and data dependencies for statecharts. We show how to slice statecharts by using this dependence graph. Our slicing approach helps systems analysts and system designers in understanding system specifications, maintaining software systems, and reusing parts of systems models
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