Who watches the watchers: Validating the ProB Validation Tool

Over the years, ProB has moved from a tool that complemented proving, to a development environment that is now sometimes used instead of proving for applications, such as exhaustive model checking or data validation. This has led to much more stringent requirements on the integrity of ProB. In this paper we present a summary of our validation efforts for ProB, in particular within the context of the norm EN 50128 and safety critical applications in the railway domain.Comment: In Proceedings F-IDE 2014, arXiv:1404.578

Adaptive development and maintenance of user-centric software systems

A software system cannot be developed without considering the various facets of its environment. Stakeholders – including the users that play a central role – have their needs, expectations, and perceptions of a system. Organisational and technical aspects of the environment are constantly changing. The ability to adapt a software system and its requirements to its environment throughout its full lifecycle is of paramount importance in a constantly changing environment. The continuous involvement of users is as important as the constant evaluation of the system and the observation of evolving environments. We present a methodology for adaptive software systems development and maintenance. We draw upon a diverse range of accepted methods including participatory design, software architecture, and evolutionary design. Our focus is on user-centred software systems

Computer-Aided Validation of Formal Conceptual Models

Conceptual modelling is the process of the software life cycle concerned with the identification and specification of requirements for the system to be built. The use of formal specification languages provides more precise and concise specifications. Nevertheless, there is still a need for techniques to support the validation of formal specifications against the informal user requirements. A limitation of formal specifications is that they cannot readily be understood by users unless they have been specially trained. However, user validation can be facilitated by exploiting the executable aspects of formal specification languages. This thesis presents a systematic approach and workbench environment to support the construction and validation through animation of TROLL specifications. Our approach is an iterative requirements definition process consisting of the formal specification of requirements, the automatic transformation of the specification into an executable form, and the interactive animation of the executable version to validate user requirements. To provide objects with persistence in the animation environment, we analyse how the static structure of TROLL objects can be mapped into relational tables. In order to execute the specification, we analyse the operational meaning of state transitions in TROLL, determine an execution model, and describe the transformation of the specifications into C++ code. We present a prototype implementation of the workbench environment.Die konzeptionelle Modellierung ist die Phase im Softwareentwurf, die sich mit der Identifikation und der Spezifikation von Systemanforderungen befasst. Formale Spezifikationssprachen ermöglichen präzisere und eindeutigere Spezifikationen. Trotzdem werden Techniken zur Validierung von formalen Spezifikationen bezüglich der informellen Benutzeranforderungen weiterhin benötigt. Ein Nachteil von formalen Spezifikationen ist, dass sie für Benutzer ohne entsprechende Vorkenntnisse nicht leicht verständlich sind. Die Einbeziehung der Benutzer in den Validierungsprozess kann jedoch durch die Ausführung der Spezifikation vereinfacht werden. Diese Arbeit liefert einen systematischen Ansatz und eine Entwicklungsumgebung für die Konstruktion von TROLL-Spezifikationen und deren Validierung durch Animation. Unser Ansatz basiert auf einem iterativen Prozess zur Anforderungsdefinition bestehend aus der formalen Spezifikation von Anforderungen, der automatischen Übersetzung der Spezifikation in eine ausführbare Form, und der interaktiven Animation um die Benutzeranforderungen zu validieren. Um die Objektzustände in der Animationsumgebung persistent zu halten, wird untersucht, wie die statische Struktur von TROLL-Objekten in relationale Tabellen umgesetzt werden kann. Um die Spezifikationen auszuführen, wird die operationale Bedeutung von TROLL-Zustandsübergängen analysiert und ein Ausführungsmodell festgelegt. Anschließend wird die Übersetzung von den Spezifikationen in C++ beschrieben. Wir zeigen eine prototypische Implementierung der Animationsumgebung

The Early Assessment of System Performance in Distributed Real-time Systems

Distributed real-time process control systems are notoriously difficult to develop. They frequently overrun time schedules and break cost constraints. The problems are compounded where there are multiple development teams and stakeholders. Conventional model-driven development has been examined to see if it can be extended to resolve some of these problems. It may be possible to use early system design stages to identify performance issues which would otherwise not be identified until late in the development of the system. A functional model is proposed, in addition to those conventionally used for model-driven development, based on loosely coupled functional elements, to represent the behaviour of each system component. The model complements existing requirements and design specifications and addresses the combination of individual component abstractions to produce a complete system specification. The functional model enables the accurate prediction of system performance prior to the detailed design of each component. The thesis examines how performance can be calculated and modelled. An animator tool and associated code generator are used to predict system and component performance in a distributed aircraft navigation system. The use of the animator to support the system design prior to the generation of the component contract specifications and interface control documents provides a means of assessing performance which is accessible to domain experts and system designers alike. The model also enables the effects of requirements changes and component design issues on the system design to be assessed in terms of the system design to provide system wide solutions. This performance assessment model and animator compliments the existing 'fix-it-later' approach, reducing the chances of performance failure detected late during the system development process when they are most expensive to fix

Applying model transformation and Event-B for specifying an industrial DSL

In this paper we describe our experience in applying the Event-B formalism for specifying the dynamic semantics of a real-life industrial DSL. The main objective of this work is to enable the industrial use of the broad spectrum of specification analysis tools that support Event-B. To leverage the usage of Event-B and its analysis techniques we developed model transformations, that allowed for automatic generation of Event-B specifications of the DSL programs. The model transformations implement a modular approach for specifying the semantics of the DSL and, therefore, improve scalability of the specifications and the reuse of their verification. Keywords: domain specific language, Event-B, model transformations, verification and validation, reuse, scalabilit

Automated Visualization of Input / Output for Processes in SOFL Formal Specifications

While formal specification is regarded as an effective means to capture accurate requirements and design, validation of the specifications remains a challenge. Specification animation has been proposed to tackle the challenge, but lacking an effective representation of the input / output data in the animation can considerably limit the understanding of the animation by clients. In this paper, we put forward a tool supported technique for visualization of the input / output data of processes in SOFL formal specifications. After discussing the motives of our work, we describe how data of each kind of data type available in the SOFL language can be visualized to facilitate the representation and understanding of input / output data. We also present a supporting tool for the technique and a case study to demonstrate the usability and effectiveness of our proposed technique

A 3D Pipeline for 2D Pixel Art Animation

Aquest document presenta un informe exhaustiu sobre un projecte destinat a desenvolupar un procés automatitzat per a la creació d'animacions 2D a partir de models 3D utilitzant Blender. L'objectiu principal del projecte és millorar les tècniques existents i reduir la necessitat que els artistes realitzin tasques repetitives en el procés de producció d'animació. El projecte implica el disseny i desenvolupament d'un complement per a Blender, programat en Python, que es va desenvolupar per ser eficient i reduir les tasques intensives en temps que solen caracteritzar algunes etapes en el procés d'animació. El complement suporta tres estils específics d'animació: l'art de píxel, "cel shader", i "cel shader" amb contorns, i es pot expandir per suportar una àmplia gamma d'estils. El complement també és de codi obert, permetent una major col·laboració i potencials contribucions per part de la comunitat. Malgrat els problemes trobats, el projecte ha estat exitós en aconseguir els seus objectius, i els resultats mostren que el complement pot aconseguir resultats similars als adquirits amb eines similars i animació tradicional. El treball futur inclou mantenir el complement actualitzat amb les últimes versions de Blender, publicar-lo a GitHub i mercats de complements de Blender, així com afegir nous estils d'art.This document presents a comprehensive report on a project aimed at developing an automated process for creating 2D animations from 3D models using Blender. The project's main goal is to improve upon existing techniques and reduce the need for artists to do clerical tasks in the animation production process. The project involves the design and development of a plugin for Blender, coded in Python, which was developed to be efficient and reduce time-intensive tasks that usually characterise some stages in the animation process. The plugin supports three specific styles of animation: pixel art, cel shading, and cel shading with outlines, and can be expanded to support a wider range of styles. The plugin is also open-source, allowing for greater collaboration and potential contributions from the community. Despite the challenges faced, the project was successful in achieving its goals, and the results show that the plugin could achieve results similar to those acquired with similar tools and traditional animation. The future work includes keeping the plugin up-to-date with the latest versions of Blender, publishing it on GitHub and Blender plugin markets, as well as adding new art styles

Executable formal specifications with Clojure

In software projects, where formal specifications are utilized, programmers usually need to know separate languages and tools for tasks related to programming and formal specifications. To remedy this situation, this thesis proposes a Clojure-based formal specification method consisting of a library and tool for writing and executing formal specifications. The library and the tool are targeted for Clojure programmers: the library enables programmers to write formal specifications with Clojure, which allows the usage of the same language for formal specifications and the implementation. The tool, that is used together with the library, allows simulating the specifications by executing them. The method presented in this thesis does not aim for formal verification with mathematical proving. Instead, the goal of the method is to offer support for formal specifications without intimidating the developers. The developed method eases the adoption of formal specifications in projects, where Clojure is used but formal specifications are still considered too costly to adopt; the library and the tool enable Clojure programmers to adopt formal specifications in their software projects without additional costs, as the language for the formal specification and the implementation is the same. The author's method also allows working iteratively from the specification to implementation because the models created with the author's library and tool can be transformed into implementation straightforwardly

Executable formal specifications of complex distributed systems with CoreASM

Formal specifications play a crucial role in the design of reliable complex software systems. Executable formal specifications allow the designer to attain early validation and verification of design using static analysis techniques and accurate simulation of the runtime behavior of the system-to-be. With increasing complexity of software-intensive computer-based systems and the challenges of validation and verification of abstract software models prior to coding, the need for interactive software tools supporting executable formal specifications is even more evident. In this paper, we discuss how CoreASM, an environment for writing and running executable specifications according to the ASM method, provides flexibility and manages the complexity by using an innovative extensible language architecture