Using formal methods to support testing

Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing

Differential Difficulty : Second Language Acquisition of English Prepositions

Article信州大学人文社会科学研究 10: 52-67(2016)departmental bulletin pape

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

Improving fault coverage and minimising the cost of fault identification when testing from finite state machines

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Software needs to be adequately tested in order to increase the confidence that the system being developed is reliable. However, testing is a complicated and expensive process. Formal specification based models such as finite state machines have been widely used in system modelling and testing. In this PhD thesis, we primarily investigate fault detection and identification when testing from finite state machines. The research in this thesis is mainly comprised of three topics - construction of multiple Unique Input/Output (UIO) sequences using Metaheuristic Optimisation Techniques (MOTs), the improved fault coverage by using robust Unique Input/Output Circuit (UIOC) sequences, and fault diagnosis when testing from finite state machines. In the studies of the construction of UIOs, a model is proposed where a fitness function is defined to guide the search for input sequences that are potentially UIOs. In the studies of the improved fault coverage, a new type of UIOCs is defined. Based upon the Rural Chinese Postman Algorithm (RCPA), a new approach is proposed for the construction of more robust test sequences. In the studies of fault diagnosis, heuristics are defined that attempt to lead to failures being observed in some shorter test sequences, which helps to reduce the cost of fault isolation and identification. The proposed approaches and techniques were evaluated with regard to a set of case studies, which provides experimental evidence for their efficacy.Brunel Research Initiative and Enterprise Fund (BRIEF) Award from Brunel University and Departmental bursary from Department of Information Systems and Computing, Brunel Universit

Formal functional testing of graphical user interfaces.

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Automated translation of VDM-SL to JML-annotated Java

When a system specified using the Vienna Development Method (VDM) is realised using code-generation, no guarantees are currently made about the correctness of the generated code. In this technical report, we improve code-generation of  VDM models by taking contract-based elements such as invariants and pre- and postconditions into account during the code-generation process. The contract-based elements of the Vienna Development Method Specification Language (VDM-SL) are translated into corresponding constructs in the Java Modelling Language (JML) and used to validate the generated code against the properties of the VDM model. VDM-SL and JML are both Design-by-Contract (DbC) languages, with the difference that VDM-SL supports abstract modelling and system specification, while JML is used for detailed specification of Java classes and interfaces. We describe the semantic differences between the contract-based elements of VDM-SL and JML and formulate the translation as a set of rules. We further demonstrate how dynamic JML assertion checks can be used to ensure the consistency of VDM’s subtypes when a model is code-generated. The translator is fully automated and produces JML-annotated Java programs that can be checked for correctness using JML tools. Specifically, it is shown how such analysis can be performed using the OpenJML runtime assertion checker. The translation is demonstrated using a case study example of an Automated Teller Machine and several other VDM-SL models, which have been used to validate and asses the translation

(How) is formulaic language universal? Insights from Korean, German and English

The existence of common expressions, also referred to as formulaic language or phraseological units, has been evidenced in a very large number of languages. However, the extent to which languages feature such formulaic material, how formulaicity may be understood across typologically different languages and whether indeed there is a concept of formulaic language that applies across languages, are questions that have been less commonly discussed. Using a novel data set consisting of topically matched corpora in three typologically different languages (Korean, German and English), this study proposes an empirically founded universal concept for formulaic language and discusses what the shape of this concept suggests for the theoretical understanding of formulaic language going forward. In particular, it is argued that the nexus of the concept of formulaic language cannot be fixed at any particular structural level (such as the phrase or the level of polylexicality) and incorporates elements specified at varying levels of abstraction (or schematicity). This means that a cross-linguistic concept of formulaic language fits in well with a constructionist view of linguistic structure

(How) is formulaic language universal? Insights from Korean, German and English

The existence of common expressions, also referred to as formulaic language or phraseological units, has been evidenced in a very large number of languages. However, the extent to which languages feature such formulaic material, how formulaicity may be understood across typologically different languages and whether indeed there is a concept of formulaic language that applies across languages, are questions that have been less commonly discussed. Using a novel data set consisting of topically matched corpora in three typologically different languages (Korean, German and English), this study proposes an empirically founded universal concept for formulaic language and discusses what the shape of this concept suggests for the theoretical understanding of formulaic language going forward. In particular, it is argued that the nexus of the concept of formulaic language cannot be fixed at any particular structural level (such as the phrase or the level of polylexicality) and incorporates elements specified at varying levels of abstraction (or schematicity). This means that a cross-linguistic concept of formulaic language fits in well with a constructionist view of linguistic structure

Animate-A-Story: Storytelling with Retrieval-Augmented Video Generation

Generating videos for visual storytelling can be a tedious and complex process that typically requires either live-action filming or graphics animation rendering. To bypass these challenges, our key idea is to utilize the abundance of existing video clips and synthesize a coherent storytelling video by customizing their appearances. We achieve this by developing a framework comprised of two functional modules: (i) Motion Structure Retrieval, which provides video candidates with desired scene or motion context described by query texts, and (ii) Structure-Guided Text-to-Video Synthesis, which generates plot-aligned videos under the guidance of motion structure and text prompts. For the first module, we leverage an off-the-shelf video retrieval system and extract video depths as motion structure. For the second module, we propose a controllable video generation model that offers flexible controls over structure and characters. The videos are synthesized by following the structural guidance and appearance instruction. To ensure visual consistency across clips, we propose an effective concept personalization approach, which allows the specification of the desired character identities through text prompts. Extensive experiments demonstrate that our approach exhibits significant advantages over various existing baselines.Comment: Github: https://github.com/VideoCrafter/Animate-A-Story Project page: https://videocrafter.github.io/Animate-A-Stor