3,386 research outputs found
Tasking Event-B: An Extension to Event-B for Generating Concurrent Code
No full textThe Event-B method is a formal approach for modelling systems in safety-, and business-critical, domains. Initially, system specification takes place at a high level of abstraction; detail is added in refinement steps as the development proceeds toward implementation. Our aim has been to develop a novel approach for generating code, for concurrent programs, from Event-B. We formulated the approach so that it integrates well with the existing Event-B methodology and tools. In this paper we introduce a tasking extension for Event-B, with Tasking and Shared Machines. We make use of refinement, decomposition, and the extension, to structure projects for code generation for multitasking implementations. During the modelling phase decomposition is performed; decomposition reduces modelling complexity and makes proof more tractable. The decomposed models are then extended with sufficient information to enable generation of code. A task body describes a task’s behaviour, mainly using imperative, programming-like constructs. Task priority and life-cycle (periodic, triggered, etc.) are also specified, but timing aspects are not modelled formally. We provide tool support in order to validate the practical aspects of the approach
The UML-B Profile for formal systems modelling in UML
No full textThe UML is a popular modelling notation that has a natural appeal to hardware and software engineers and is adaptable through extension mechanisms. Formal (mathematical) modelling languages, on the other hand, are seen as difficult and costly to use and have achieved only limited use despite the benefits that they offer. In previous work, we have proposed an integration of UML and the formal notation, B and provided an automatic translator that produces a B specification. The integrated modelling notation, UML-B, inherits from both UML and B but primarily, is a specialisation of the UML. To achieve this integration we have specialised UML modelling elements via stereotypes, added tagged values to represent B modelling features and imposed constraints to ensure that UML-B models are translated into usable B. Here we describe ongoing work to define UML-B as a profile in accordance with the UML extensibility mechanisms
Rigorous development of reusable, domain-specific components, for complex applications
No full textThe reuse of reliable, domain-specific software components is a strategy commonly used in the avionics industry to develop safety critical airborne systems. One method of achieving reuse is to use domain specific languages that map closely onto abstractions in the problem domain. While this works well for control algorithms, it is less successful for some complex ancillary functions such as failure management. The characteristics of device failures are often difficult to predict resulting in late requirements changes. Hence a small semantic gap is especially desirable but difficult to achieve. Object-oriented design techniques include mechanisms, such as inheritance, that cater well for variations in behaviour. However, object-oriented notations such as the UML lack the precision, and rigor, needed for safety critical software. UML-B is a profile of the UML for formal modelling. In this paper we show how UML-B can be used to model failure management systems via progressive refinement, and indicate how this approach could utilise UML concepts to cope with high variability, while providing rigorous verification
Michel Foucault and Judith Butler: troubling Butler's appropriation of Foucault's work
No full textOne of the main influences on Judith Butler‘s thinking has been the work of Michel Foucault. Although this relationship is often commented on, it is rarely discussed in any detail. My thesis makes a contribution in this area. It presents an analysis of Foucault‘s work with the aim of countering Butler‘s representation of his thinking. In the first part of the thesis, I show how Butler initially interprets Foucault‘s project through Nietzschean genealogy, psychoanalysis and Derridean discourse, and how she later develops this interpretation in line with the progress of her own project. In the main part of the thesis, I present an analysis of Foucault‘s thinking in the period from The Archaeology of Knowledge (1969) to The History of Sexuality volume 1 (1976). This analysis focuses on the aspect of his work which has most influenced Butler‘s thinking: namely the notion of a relationship between knowledge, discourse and power. The other issues in his work which Butler addresses—genealogy, the subject, the body, abnormality, and sexuality—are discussed within this framework. I show how, in the early 1970s, Foucault develops the notion of power-knowledge, and sets out a relationship between power-knowledge and discourse which is overlooked by Butler. I argue that Butler interprets Foucaultian power through the notions of repression and social norms, and ignores the concepts of technology and strategy which form a key part of Foucault‘s thinking. I show how, from The Archaeology of Knowledge on, Foucault develops a socio-historical ontology and a genealogy of the subject, both of which are at variance with Butler‘s interpretation of his thinking
Towards a method for rigorous development of generic requirements patterns
No full textWe 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
Towards a methodology for rigorous development of generic requirements patterns
No full textWe present work in progress on a methodology 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. We consider the failure detection and management function for engine control systems as an application domain where product line engineering is useful. The methodology produces a generic requirement set in our, UML based, formal notation, UML-B. The formal verification both of the generic requirement set, and of a particular application, is achieved via translation to the formal specification language, B, using our U2B and ProB tools
Genomewide association scan of suicidal thoughts and behaviour in major depression
No full textBACKGROUND: Suicidal behaviour can be conceptualised as a continuum from suicidal ideation, to suicidal attempts to completed suicide. In this study we identify genes contributing to suicidal behaviour in the depression study RADIANT. METHODOLOGY/PRINCIPAL FINDINGS: A quantitative suicidality score was composed of two items from the SCAN interview. In addition, the 251 depression cases with a history of serious suicide attempts were classified to form a discrete trait. The quantitative trait was correlated with younger onset of depression and number of episodes of depression, but not with gender. A genome-wide association study of 2,023 depression cases was performed to identify genes that may contribute to suicidal behaviour. Two Munich depression studies were used as replication cohorts to test the most strongly associated SNPs. No SNP was associated at genome-wide significance level. For the quantitative trait, evidence of association was detected at GFRA1, a receptor for the neurotrophin GDRA (p = 2e-06). For the discrete trait of suicide attempt, SNPs in KIAA1244 and RGS18 attained p-values of <5e-6. None of these SNPs showed evidence for replication in the additional cohorts tested. Candidate gene analysis provided some support for a polymorphism in NTRK2, which was previously associated with suicidality. CONCLUSIONS/SIGNIFICANCE: This study provides a genome-wide assessment of possible genetic contribution to suicidal behaviour in depression but indicates a genetic architecture of multiple genes with small effects. Large cohorts will be required to dissect this further.Alexandra Schosser, Amy W. Butler, Marcus Ising, Nader Perroud, Rudolf Uher, Mandy Y. Ng, Sarah Cohen-Woods, Nick Craddock, Michael J. Owen, Ania Korszun, Lisa Jones, Ian Jones, Michael Gill, John P. Rice, Wolfgang Maier, Ole Mors, Marcella Rietschel, Susanne Lucae, Elisabeth B. Binder, Martin Preisig, Julia Perry, Federica Tozzi, Pierandrea Muglia, Katherine J. Aitchison, Gerome Breen, Ian W. Craig, Anne E. Farmer, Bertram Müller-Myhsok, Peter McGuffin and Cathryn M. Lewi
Thamnoecha uniformis Butler 1875
No full text<i>Thamnoecha uniformis</i> (Butler, 1875) <p>Plate 1, Fig. 21</p> <p> <b>Material examined. PAKISTAN, [Islamabad,]</b> 20km N Islamabad, Margalla Hills, Pir Sowaha, 33°50’N 72°55’E, 600m, vii. 1995 (CRBP).</p> <p> <b>Remarks.</b> This is the first record of this species from Pakistan. It is restricted to northern Pakistan, northwestern India and Nepal.</p>Published as part of <i>Rafi, Muhammad Ather, Sultan, Amir, Kitching, Ian J., Pittaway, Anthony R., Markhasiov, Maxim, Khan, Muhammad Rafique & Naz, Falak, 2014, The Hawkmoth Fauna of Pakistan (Lepidoptera: Sphingidae), pp. 393-418 in Zootaxa 3794 (3)</i> on page 399, DOI: 10.11646/zootaxa.3794.3.4, <a href="http://zenodo.org/record/230551">http://zenodo.org/record/230551</a>
Transforming Power Relationships: Leadership, Risk, and Hope. IHS Political Science Series No. 135, May 2013
No full textChronic communal conflicts resemble the prisoner’s dilemma. Both communities prefer peace to war. But neither trusts the other, viewing the other’s gain as its own loss, so
potentially shared interests often go unrealized.
Achieving positive-sum outcomes from apparently zero-sum struggles requires a kind of riskembracing leadership. To succeed leaders must: a) see power relations as potentially
positive-sum; b) strengthen negotiating adversaries instead of weakening them; and c) demonstrate hope for a positive future and take great personal risks to achieve it.
Such leadership is exemplified by Nelson Mandela and F.W. de Klerk in the South African democratic transition. To illuminate the strategic dilemmas Mandela and de Klerk faced, we examine the work of Robert Axelrod, Thomas Schelling, and Josep Colomer, who highlight important dimensions of the problem but underplay the role of risk-embracing leadership. Finally we discuss leadership successes and failures in the Northern Ireland settlement and the Israeli-Palestinian conflict
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