From English to formal specifications

Formal methods provide an approach in which design steps can be shown to satisfy a specification. However, if a formal specification is wrong, then although the design steps may satisfy the formal specification, they are unlikely to satisfy the requirements of the system. Since most users are unfamiliar with formal methods, requirements specifications are often written in English. Such requirements, expressed in English, are then somehow translated to formal specifications. This transition has some potential for introducing errors and inconsistencies. In this paper we propose an interactive approach to proceeding from an informal specification to a formal specification in a systematic manner. The approach uses research in the area of natural language understanding to analyse English specifications in order to detect ambiguities and to generate an entity relationship model. The entity relationship model is then used as a basis for producing VDM data types and the specifications of some common operations. We illustrate the effectiveness of our approach by applying it to the specification of part of a route planning database system

From English to formal specifications

Specifications provide the foundation upon which a system can be formally developed. If a specification is wrong, then no matter what method of design is used, or what quality assurance procedures are in place, they willnot result in a system that meets the requirements.The specification of a system involves people of different profiles who favour different representations. At the beginning natural language is used because the specification document acts as a contract between the user and the developers. Most of the time, the only representation that users understand and agree on is natural language. At the other end, developers findnatural language specifications ambiguous and incomplete and may therefore prefer formal specifications. The transition from informal specifications to formal ones is an error prone and time consuming process. This transitionmust be supported to ensure that the formal specifications are consistent with the informal ones.In this research we propose an interactive approach for producing formal specifications from English specifications. The approach uses research in the area of natural language understanding to analyse English specifications in order to detect ambiguities. The method used for analysing natural language text is based on McCord’s approach. This method consists oftranslating natural language sentences into a logical form language representation.This helps to identify ambiguities present in natural language specifications and to identify the entities and relationships. These entities and relationships are used as a basis for producing VDM data types.We also investigate the production of data type invariants for restricted sentences and the production of some common specifications.We test our approach by implementing it in Prolog-2 and apply it to an independent case study

Tools for producing formal specifications : a view of current architectures and future directions

During the last decade, one important contribution towards requirements engineering has been the advent of formal specification languages. They offer a well-defined notation that can improve consistency and avoid ambiguity in specifications. However, the process of obtaining formal specifications that are consistent with the requirements is itself a difficult activity. Hence various researchers are developing systems that aid the transition from informal to formal specifications. The kind of problems tackled and the contributions made by these proposed systems are very diverse. This paper brings these studies together to provide a vision for future architectures that aim to aid the transition from informal to formal specifications. The new architecture, which is based on the strengths of existing studies, tackles a number of key issues in requirements engineering such as identifying ambiguities, incompleteness, and reusability. The paper concludes with a discussion of the research problems that need to be addressed in order to realise the proposed architecture

Generating natural language specifications from UML class diagrams

Early phases of software development are known to be problematic, difficult to manage and errors occurring during these phases are expensive to correct. Many systems have been developed to aid the transition from informal Natural Language requirements to semistructured or formal specifications. Furthermore, consistency checking is seen by many software engineers as the solution to reduce the number of errors occurring during the software development life cycle and allow early verification and validation of software systems. However, this is confined to the models developed during analysis and design and fails to include the early Natural Language requirements. This excludes proper user involvement and creates a gap between the original requirements and the updated and modified models and implementations of the system. To improve this process, we propose a system that generates Natural Language specifications from UML class diagrams. We first investigate the variation of the input language used in naming the components of a class diagram based on the study of a large number of examples from the literature and then develop rules for removing ambiguities in the subset of Natural Language used within UML. We use WordNet,a linguistic ontology, to disambiguate the lexical structures of the UML string names and generate semantically sound sentences. Our system is developed in Java and is tested on an independent though academic case study

Formal verification of interactive computing systems: Opportunities and challenges

Formal verification has the potential to provide a level of evidence based assurance not possible by more traditional development approaches. For this potential to be fulfilled, its integration into existing practices must be achieved. Starting from this premise, the position paper discusses the opportunities created and the challenges faced by the use of formal verification in the analysis of critical interactive computing systems. Three main challenges are discussed: the accessibility of the modelling stage; support for expressing relevant properties; the need to provide analysis results that are comprehensible to a broad range of expertise including software, safety and human factors.This work is financed by the ERDF - European Regional Development Fundthrough the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme and by National Funds through the Portuguese funding agency, FCT - Fundação para a Ciência e a Tecnologia, within project POCI-01-0145-FEDER-016826