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

A comparative reliability analysis of ETCS train radio communications

StoCharts have been proposed as a UML statechart extension for performance and dependability evaluation, and were applied in the context of train radio reliability assessment to show the principal tractability of realistic cases with this approach. In this paper, we extend on this bare feasibility result in two important directions. First, we sketch the cornerstones of a mechanizable translation of StoCharts to MoDeST. The latter is a process algebra-based formalism supported by the Motor/Möbius tool tandem. Second, we exploit this translation for a detailed analysis of the train radio case study

From StoCharts to MoDeST: a comparative reliability analysis of train radio communications

StoCharts have been proposed as a UML statechart extension for performance and dependability evaluation, and have been applied in the context of train radio reliability assessment to show the principal tractability of realistic cases with this approach. In this paper, we extend on this bare feasibility result in two important directions. First, we sketch the cornerstones of a mechanizable translation of StoCharts to MoDeST. The latter is a process algebra-based formalism supported by the Motor/Möbius tool tandem. Second, we exploit this translation for a detailed analysis of the train radio case study

A model checker for performance and dependability properties

Markov chains are widely used in the context of performance and reliability evaluation of systems of various nature. Model checking of such chains with respect to a given (branching) temporal logic formula has been proposed for both the discrete [8] and the continuous time setting [1], [3]. In this short paper, we describe the prototype model checker $E \vdash M C^2$ for discrete and continuous-time Markov chains, where properties are expressed in appropriate extensions of CTL.We illustrate the general benefits of this approach and discuss the structure of the tool

Transformation of UML Behavioral Diagrams to Support Software Model Checking

Unified Modeling Language (UML) is currently accepted as the standard for modeling (object-oriented) software, and its use is increasing in the aerospace industry. Verification and Validation of complex software developed according to UML is not trivial due to complexity of the software itself, and the several different UML models/diagrams that can be used to model behavior and structure of the software. This paper presents an approach to transform up to three different UML behavioral diagrams (sequence, behavioral state machines, and activity) into a single Transition System to support Model Checking of software developed in accordance with UML. In our approach, properties are formalized based on use case descriptions. The transformation is done for the NuSMV model checker, but we see the possibility in using other model checkers, such as SPIN. The main contribution of our work is the transformation of a non-formal language (UML) to a formal language (language of the NuSMV model checker) towards a greater adoption in practice of formal methods in software development.Comment: In Proceedings FESCA 2014, arXiv:1404.043

A model driven approach for software systems reliability

The reliability assurance of software systems from design to deployment level through transformation techniques and model driven approach, is described. Once the reliability mechanisms provided by current component-based development architectures (CBDA) are designed in a platform-independent way, platform-based design and implementation models must be extended. Current CBDAs, such as Enterprise Java Beans, address a considerable range of features to support system reliability. The evaluation aims to test maturity of the approach, its applicability, and the effectiveness of reliability models. The techniques such as process algebras are generally considered time consuming, in regard to software development

Scenario-Based Development and Verification of Domain-Specific Languages

The use of domain-specific languages (DSLs) has increased manifold for problem solving in specific domain areas as they allow for a wider variety of expressions within their domain. Modeling using DSLs has shown high increases in productivity after accounting for the time and cost expended in developing them, making them a suitable target for improvement in order to reap higher rewards. The currently used approach for domain modeling involves the creation of an ontology which is then used to describe the domain model. This ontology encapsulates all domain knowledge and can be cumbersome to create, requiring external sources of information and assistance from a domain expert. This dissertation first discusses the use and importance of DSLs for scenario generation for a domain and presents an extension to the Aviation Scenario Definition Language (ASDL). The main contribution of this dissertation is a novel framework for scenario based development of DSLs, called the Domain-Specific Scenario (DoSS) framework. This framework proposes the use of scenarios in natural language, which are currently used in requirements engineering and testing, as the basis for developing the domain model iteratively. An example of the use of this approach is provided by developing a domain model for ASDL and comparing the published model with one obtained using DoSS. This approach is supplemented with a case study to validate the claim that DoSS is easier to use by non-experts in the domain by having a user create a model and comparing it to one obtained by the author. These models were found to be almost identical, showing a promising return for this approach. The time taken and effort required to create this model by the user were recorded and found to be quite low, although no similar results have been published so no comparison could be made. State charts are then used for verification of scenarios to ensure the conformity between scenarios and models. The dissertation also discusses applications of the ideas presented here, specifically, the use of ASDL for Air Traffic Control training scenarios and the use of DoSS for ontology generation