We present PROB, an animation and model checking tool for the B method PROB's animation facilities allow users to gain confidence in their specifications, and unlike the animator provided by the B-Toolkit, the user does not have to guess the right values for the operation arguments or choice variables PROB contains a model checker and a constraint-based checker, both of which can be used to detect various errors in B specifications We present our first experiences in using PROB on several case studies, highlighting that PROB enables users to uncover errors that are not easily discovered by existing tools

ProB: A model checker for B

Industries like telecommunications, medical, automotive, military, avionics, and aerospace use complex real-time systems. Specification and Description Language (SDL) is one of the leading domain specific languages that is formally defined by international standards and well established in describing such systems. To check system properties abstracted model of the system is prepared in selected modeling language. We use Spin (Simple Promela Interpreter) model checker that is one of the leading tools for verification of complex concurrent and reactive systems. This paper focuses on modeling the SDL timer construct. It is one of the SDL constructs that is not easily modeled with Promela, but is present in many SDL systems. After an overview of the related work we propose a new Discrete Time Model for Promela (DTMP) that is seamlessly integrated in our framework for modeling SDL systems and can be used with the mainstream version of the Spin tool. To the best of our knowledge, this is not possible with the existing solutions. We describe how DTMP can be used to model SDL systems that use timers. Experimental results demonstrate its applicability to non-SDL systems with Fischer’s mutual exclusion protocol and the Parallel Acknowledgment with Retransmission that were used in prior studies. We compare state-space requirements with one of the existing solutions DT Promela and DT Spin. With that, virtues and shortcomings of this high-level solution are exposed. We have shown that DTMP is effective when an extensive range of timer expiration values are used, which is usually the case in real-life SDL systems.

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Discrete Time Model for Process Meta Language with Fictitious-Clock

This paper tackles the problem of model-checking SDL programs that use the save operator. Previous work on model-checking SDL programs with SPIN consisted in translating SDL into IF (using sdl2if) and finally IF to Promela (if2pml). However, the save operator of SDL is not handled by the (final) translator if2pml. We propose an extension of the if2pml tool that translates IF into Promela programs with save operators. We also add an abstraction method on buffer messages to if2pml allowing the user to gather some buffer messages into one abstract value. We use our extended version of if2pml to validate an Unmanned Under-water Vehicle (UUV) subsystem specified with SDL.

Extending translation from SDL to Promela

The paper introduces handover system by use of two radio connections fitted in the train operating on different channels as well as use of the train's location and directional information to aid in reducing ping pong during handover. The paper formulates the Global Systems for Mobiles Railway (GSM-R) algorithm to help make decisions on when to handover with the objective of minimizing the handoff latency. These measures allow seamless connection to the network while moving along the railway boundaries which improves communication. This reduces outage duration. Simulation of the system is done using MATLAB. The algorithm used is disruption free and quite effective in high speed train travel, and the handoff decision is very efficient and more exact. This will therefore significantly improve service availability and reduce latency in data communication.

Handover Enhancement in Wireless Communication-Based Train Control Systems

The integrated communication infrastructure is the core of the Smart Grid architecture. Its two-way communication and information flow provides this network with all needed resources in order to control and manage all connected components from the utility to the customer side. This latter, named the Home Area Network or HAN, is a dedicated network connecting smart devices inside the customer home, and using different solutions. In order to avoid problems and anomalies along the process life cycle of developing a new solution for HAN network, the modeling and validation is one of the most powerful tools to achieve this goal. This paper presents a practical case study of such validation. It intends to validate a HAN SDL model, described in a previous work, using model checking techniques. It introduces a method to translate the SDL model to a Promela model using an intermediate format IF. After the generation of the Promela model, verification is performed to ensure that some functional properties are satisfied. The desired properties are defined in Linear Temporal Logic (LTL), and DTSPIN (an extension of SPIN with discrete time) model checker is used to verify the correctness of the model.

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Soufiane Zahid

Papers

Practical Model Checking of a Home Area Network System: Case Study