Towards a method for rigorous development of generic requirements patterns

We present work in progress on a method for the engineering, validation and verification of generic requirements using domain engineering and formal methods. The need to develop a generic requirement set for subsequent system instantiation is complicated by the addition of the high levels of verification demanded by safety-critical domains such as avionics. Our chosen application domain is the failure detection and management function for engine control systems: here generic requirements drive a software product line of target systems. A pilot formal specification and design exercise is undertaken on a small (twosensor) system element. This exercise has a number of aims: to support the domain analysis, to gain a view of appropriate design abstractions, for a B novice to gain experience in the B method and tools, and to evaluate the usability and utility of that method.We also present a prototype method for the production and verification of a generic requirement set in our UML-based formal notation, UML-B, and tooling developed in support. The formal verification both of the structural generic requirement set, and of a particular application, is achieved via translation to the formal specification language, B, using our U2B and ProB tools

Assessing Unmet Needs of Caregivers after Stroke: Occupational Therapist Practices and Perspectives

Background: Family caregivers of stroke survivors often feel unprepared and overwhelmed post discharge with numerous unmet needs. Occupational therapists can play an integral role in addressing family caregivers’ needs. Limited research exists on assessment practices of occupational therapists in identifying caregivers’ needs poststroke. This study explores the practices and perspectives of occupational therapists in assessing unmet caregivers’ needs. Method: A cross-sectional, mixed methods research design was used to electronically survey 15 occupational therapists. Part 1 of the survey explored participant methods for identifying caregivers’ needs and their views on using formal caregiver assessment tools. Part 2 gathered participant perspectives on three selected caregiver assessments. Descriptive statistics and thematic analysis were used to interpret the data. Results: The participants perceive formal assessments as beneficial. However, they use informal strategies to assess the unmet needs of caregivers rather than formal assessment. Reimbursement challenges, productivity pressure, and questionable necessity are barriers to conducting formal assessments. Advantages and disadvantages of each assessment are discussed. Conclusion: Occupational therapists face barriers to conducting formal assessment across settings. Implementation of recent policies is needed to further support occupational therapy’s role in addressing caregivers’ needs. This study can inform future development of assessment tools tailored to occupational therapy

Formal verification and testing: An integrated approach to validating Ada programs

An integrated set of tools called a validation environment is proposed to support the validation of Ada programs by a combination of methods. A Modular Ada Validation Environment (MAVEN) is described which proposes a context in which formal verification can fit into the industrial development of Ada software

Score, Pseudo-Score and Residual Diagnostics for Spatial Point Process Models

We develop new tools for formal inference and informal model validation in the analysis of spatial point pattern data. The score test is generalized to a "pseudo-score" test derived from Besag's pseudo-likelihood, and to a class of diagnostics based on point process residuals. The results lend theoretical support to the established practice of using functional summary statistics, such as Ripley's $K$-function, when testing for complete spatial randomness; and they provide new tools such as the compensator of the $K$-function for testing other fitted models. The results also support localization methods such as the scan statistic and smoothed residual plots. Software for computing the diagnostics is provided.Comment: Published in at http://dx.doi.org/10.1214/11-STS367 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Experience with mural in formalising Dust-Expert

The mural system was an outcome of a significant effort to develop a support tool for the effective use of a full formal methods development cycle. Experience with it, however, has been limited to a small number of illustrative examples that have been carried out by those closely associated with its development and implementation. This paper aims to remedy this situation by describing the experience of using mural for specifying Dust-Expert, an expert system for the relief venting of dust explosions in chemical processes. The paper begins by summarising the main requirements for Dust-Expert, and then gives a ¯avour of the VDM speci®cation that was formalised using mural. The experience of using mural is described with respect to users' expectations that a formal methods tool should: (i) spot any inconsistencies; (ii) help manage and organise the specifications and allow one to easily add, access, update and delete specifications; (iii) help manage and carry out the refinement process; (iv) help manage and organise theories; (v) help manage and carry out proofs. The paper concludes by highlighting the strengths and weaknesses of mural that could be of interest to those developing the next generation of formal methods development tools

Formal methods technology transfer: Some lessons learned

IBM has a long history in the application of formal methods to software development and verification. There have been many successes in the development of methods, tools and training to support formal methods. And formal methods have been very successful on several projects. However, the use of formal methods has not been as widespread as hoped. This presentation summarizes several approaches that have been taken to encourage more widespread use of formal methods, and discusses the results so far. The basic problem is one of technology transfer, which is a very difficult problem. It is even more difficult for formal methods. General problems of technology transfer, especially the transfer of formal methods technology, are also discussed. Finally, some prospects for the future are mentioned

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

What lies between design intent coverage and model checking?

Practitioners of formal property verification often work around the capacity limitations of formal verification tools by breaking down properties into smaller properties that can be checked on the sub-modules of the parent module. To support this methodology, we have developed a formal methodology for verifying whether the decomposition is indeed sound and complete, that is, whether verifying the smaller properties on the submodules actually guarantees the original property on the parent module. In practice, however designers do not write properties for all modules and thereby our previous methodology was applicable to selected cases only. In this paper we present new formal methods that allow us to handle RTL blocks in the analysis. We believe that the new approach will significantly widen the scope of the methodology, thereby enabling the validation engineer to handle much larger designs than admitted by existing formal verification tools

Social media enhanced boundary crossing: exploring distance students' ecosystems of learning support

As the demand for distance learning increases, traditional campus-based universities continue to struggle in supporting working distance students. This has resulted in the increased phenomena of students using social media within their ecosystems of learning support. The use of formal and informal tools such as social media gives rise to boundaries which students need to cross for effective support. How social media facilitates the crossing of boundaries within ecosystems of learning support remains an unfamiliar area of research. This study employed a predominately qualitative research methods, with a small element being a quantitative method to view and investigate postgraduate distance students' ecosystem of learning support holistically. The findings of this study revealed that participants used a combination of formal and informal tools to support their learning, including social media. In particular WhatsApp, which enables the crossing of transitional, formal and informal learning contexts, hierarchical and, time and space boundaries. Recognizing social media as an important part of students' learning support ecosystem, allowed an expanded view on learning support. As such, the study highlighted a range of different learning mechanisms which occur when students cross these boundaries, with coordination being the dominant learning mechanism. In conclusion, social media (such as WhatsApp) does indeed enhance the crossing of various boundaries to support learning. However, some students do not necessarily perceive their interaction on social media as learning, which speaks to the need of legitimising social media as learning tools by institutions. This study then recommends the need for institutions to recognize and nurture the use of social media as one element of a distance learning support ecosystem for cost-effective student support strategies guided by institutional guidelines and policies