Proceedings of the 11th Overture Workshop

The 11th Overture Workshop was held in Aarhus, Denmark on Wed/Thu 28–29th Au- gust 2013. It was the 11th workshop in the current series focusing on the Vienna De- velopment Method (VDM) and particularly its community-based tools development project, Overture (http://www.overturetool.org/), and related projects such as COMPASS(http://www.compass-research.eu/) and DESTECS (http://www.destecs.org). Invited talks were given by Yves Ledru and Joe Kiniry. The workshop attracted 25 participants representing 10 nationalities. The goal of the workshop was to provide a forum to present new ideas, to identify and encourage new collaborative research, and to foster current strands of work towards publication in the mainstream conferences and journals. The Overture initiative held its first workshop at FM’05. Workshops were held subsequently at FM’06, FM’08 and FM’09, FM’11, FM’12 and in between

On the Extensibility of Formal Methods Tools

Modern software systems often have long lifespans over which they must continually evolve to meet new, and sometimes unforeseen, requirements. One way to effectively deal with this is by developing the system as a series of extensions. As requirements change, the system evolves through the addition of new extensions and, potentially, the removal of existing extensions. In order for this kind of development process to thrive, it is necessary that the system have a high level of extensibility. Extensibility is the capability of a system to support the gradual addition of new, unplanned functionalities. This dissertation investigates extensibility of software systems and focuses on a particular class of software: formal methods tools. The approach is broad in scope. Extensibility of systems is addressed in terms of design, analysis and improvement, which are carried out in terms of source code and software architecture. For additional perspective, extensibility is also considered in the context of formal modelling. The work carried out in this dissertation led to the development of various extensions to the Overture tool supporting the Vienna Development Method, including a new proof obligation generator and integration with theorem provers. Additionally, the extensibility of Overture itself was also improved and it now better supports the development and integration of various kinds of extensions. Finally, extensibility techniques have been applied to formal modelling, leading to an extensible architectural style for formal models

On Extensibility of Software Systems

This report contains the progress report written as part of the author's PhD qualifying exam. It describes initial work carried out in analyzing and improving the extensibility of software systems, including a detailed case study analyzing the extensibility of the Proof Obligation Generator (POG) of the Overture tool. Additional extension work includes improving the output format of the POG and support for additional logic systems. Future work for the remaining half of the PhD is also discussed, including ways to combine formal modelling and extensibility analysis and also techniques for multi-paradigm extensibility

Enhancing Formal Modelling Tool Support with Increased Automation

Progress report for the qualification exam report for PhD Student Kenneth Lausdahl. Initial work on enhancing tool support for the formal method VDM and the concept of unifying a abstract syntax tree with the ability for isolated extensions is described. The tool support includes a connection to UML and a test automation principle based on traces written as a kind of regular expressions

Enhancing System Realisation in Formal Model Development

Software for mission-critical systems is sometimes analysed using formal specification to increase the chances of the system behaving as intended. When sufficient insights into the system have been obtained from the formal analysis, the formal specification is realised in the form of a software implementation. One way to realise the system's software is by automatically generating it from the formal specification -- a technique referred to as code generation. However, in general it is difficult to make guarantees about the correctness of the generated code -- especially while requiring automation of the steps involved in realising the formal specification. This PhD dissertation investigates ways to improve the automation of the steps involved in realising and validating a system based on a formal specification. The approach aims to develop properly designed software tools which support the integration of formal methods tools into the software development life cycle, and which leverage the formal specification in the subsequent validation of the system. The tools developed use a new code generation infrastructure that has been built as part of this PhD project and implemented in the Overture tool -- a formal methods tool that supports the Vienna Development Method. The development of the code generation infrastructure has involved the re-design of the software architecture of Overture. The new architecture brings forth the reuse and extensibility features of Overture to take into account the needs and requirements of software extensions targeting Overture. The tools developed in this PhD project have successfully supported three case studies from externally funded projects. The feedback received from the case study work has further helped improve the code generation infrastructure and the tools built using it

Using Executable VDM++ Models in an Industrial Application - Self-defense System for Fighter Aircraft

When developing complex software systems, one of the most significant challenges is to make sure that the customer and developer agree on the requirements of the system. By using executable models early in the development process, a higher degree of confidence can be gained in the system design and misunderstandings or ambiguous functional requirements can be avoided. This paper presents an industrial case of a communication protocol between two parts of a selfdefense system used on-board fighter aircraft. An executable model of both systems were created using the Vienna Development Method (VDM), and exercised using many scenarios to cover different corner cases. This was done as an alternative to analysing all the scenarios by hand, which would be much more time consuming and far more error prone. The results of the scenario based tests were used to communicate with the customer and ensure that agreement of the requirements was reached

Proceedings of the 9th Overture Workshop

This report contains the proceedings of The 9th Overture Workshop, held in Limerick on 20th June 2011