From Event-B models to Dafny code contracts

International audienceThe constructive approach to software correctness aims at formal modelling and verification of the structure and behaviour of a system in different levels of abstraction. In contrast, the analytical approach to software verification focuses on code level correctness and its verification. Therefore it would seem that the constructive and analytical approaches should complement each other well. To demonstrate this idea we present a case for linking two existing verification methods, Event-B (constructive) and Dafny (analytical). This approach combines the power of Event-B abstraction and its stepwise refinement with the verification capabilities of Dafny. We presented a small case study to demonstrate this approach and outline of the rules for transforming Event-B events to Dafny contracts. Finally, a tool for automatic generation of Dafny contracts from Event-B formal models is presented

Rethinking Knowledge and Pedagogy in Dental Education

Dentistry as a profession has often been considered both art and science. Traditional dental education has attempted to address both; however, in many places only the science of dentistry is emphasized. The move toward competency-based curricula in dental education requires an expansion of what constitutes meaningful knowledge in the curriculum and what pedagogies best support that curriculum. The scientific and technical knowledge considered foundational to clinical practice is not sufficient to teach competencies associated with the art of dentistry. Habermas, a social scientist, offers a way of looking beyond technical knowledge to consider two other forms of knowledge: practical and emancipatory. Pedagogy that supports development of practical and emancipatory knowledge includes problem-based learning and case methods, heuristics, reflective practica, journals, storytelling, and performance-based assessment methods. These important teaching strategies are being integrated into various dental curricula including a new competency-based dental curriculum at Marquette University\u27s School of Dentistry. It will be critical for dental educators to continue developing these methods to provide efficient and effective education for future practitioners in both the art and science of dentistry

Random walks of Wilson loops in the screening regime

Dynamics of Wilson loops in pure Yang-Mills theories is analyzed in terms of random walks of the holonomies of the gauge field on the gauge group manifold. It is shown that such random walks should necessarily be free. The distribution of steps of these random walks is related to the spectrum of string tensions of the theory and to certain cumulants of Yang-Mills curvature tensor. It turns out that when colour charges are completely screened, the holonomies of the gauge field can change only by the elements of the group center, which indicates that in the screening regime confinement persists due to thin center vortices. Thick center vortices are also considered and the emergence of such stepwise changes in the limits of infinitely thin vortices and infinitely large loops is demonstrated.Comment: Major revision of the previous version, to appear in Nucl. Phys. B (10 pages RevTeX, 3 figures

The value of theoretical multiplicity for steering transitions towards sustainability

Transition management, as a theory of directing structural societal changes towards sustainable system innovations, has become a major topic in scientific research over the last years. In this paper we focus on the question how transitions towards sustainability can be steered, governed or managed, in particular by governmental actors. We suggest an approach of theoretical multiplicity, arguing that multiple theories will be needed simultaneously for dealing with the complex societal sustainability issues. Therefore, we address the steering question by theoretically comparing transition management theory to a number of related theories on societal change and intervention, such as multi-actor collaboration, network governance, configuration management, policy agenda setting, and adaptive management. We conclude that these related theories put the managerial assumptions of transition management into perspective, by adding other steering roles and leadership mechanisms to the picture. Finally we argue that new modes of steering inevitable have consequences for the actual governance institutions. New ways of governing change ask for change within governance systems itself and vice versa. Our argument for theoretical multiplicity implicates the development of multiple, potentially conflicting, governance capacitie

Renewable and Nonrenewable Resource Theory Applied to Coastal Agriculture, Forest, Wetland, and Fishery Linkages

This paper addresses tradeoffs in wetland development using a framework that integrates economic theory of renewable and nonrenewable resources. The theory treats wetland development as use of a nonrenewable resource, while wetland preservation protects critical fishery habitat. The framework recognizes that wetland quality may vary for either development or fisheries. An illustrative application assesses tradeoffs in converting pocosin wetlands to agriculture rather than maintaining wetlands to protect salinity in estuarine nursery areas. Results reveal the marginal value of salinity protection may be substantial, while location may affect a wetland's value to an estuarine shrimp fishery. Comparisons between agricultural and forestry landuses show that ecological links may cause wetland values to depend upon the land-use chosen for the developed state. Future assessments of other development may reveal additional impacts through impacts on salinity.nonrenewable, renewable, fishery, wetland value, pocosin, Pamlico Sound, Community/Rural/Urban Development, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,

Vulnerabilities and responsibilities: dealing with monsters in computer security

Purpose – The purpose of this paper is to analyze information security assessment in terms of cultural categories and virtue ethics, in order to explain the cultural origin of certain types of security vulnerabilities, as well as to enable a proactive attitude towards preventing such vulnerabilities.\ud \ud Design/methodology/approach – Vulnerabilities in information security are compared to the concept of “monster” introduced by Martijntje Smits in philosophy of technology. The applicability of different strategies for dealing with monsters to information security is discussed, and the strategies are linked to attitudes in virtue ethics.\ud \ud Findings – It is concluded that the present approach can form the basis for dealing proactively with unknown future vulnerabilities in information security.\ud \ud Research limitations/implications – The research presented here does not define a stepwise approach for implementation of the recommended strategy in practice. This is future work.\ud \ud Practical implications – The results of this paper enable computer experts to rethink their attitude towards security threats, thereby reshaping their practices.\ud \ud Originality/value – This paper provides an alternative anthropological framework for descriptive and normative analysis of information security problems, which does not rely on the objectivity of risk

Metastability, Criticality and Phase Transitions in brain and its Models

This essay extends the previously deposited paper "Oscillations, Metastability and Phase Transitions" to incorporate the theory of Self-organizing Criticality. The twin concepts of Scaling and Universality of the theory of nonequilibrium phase transitions is applied to the role of reentrant activity in neural circuits of cerebral cortex and subcortical neural structures

Theoretical multiplicity for the governance of transitions. The energy producing greenhouse case

Transition management, as a theory of directing structural societal changes towards sustainable system innovations, has become a major topic in scientific research over the last years. In the Netherlands, the concept of transition management was adopted by several governmental agencies as one of the leading principles for steering sustainable development. In this paper we focus on the governance of transitions. The question is if and how transitions towards sustainability can be steered, governed or managed, in particular by governmental actors. We suggest an approach of theoretical multiplicity, arguing that multiple theories will be needed simultaneously for dealing with the complex societal sustainability issues. Therefore, we address the governance question by theoretically comparing transition management theory to a number of related theories on societal change and intervention, such as multi-actor collaboration, network governance, policy agenda setting and adaptive governance. We argue that these related theories put the managerial assumptions of transition management into perspective, by adding other steering roles and leadership mechanisms to the picture. We will illustrate the advantages of theoretical multiplicity by analysing the case of the greenhouse as a source of energy. The energy producing greenhouse can be considered a revolutionary technology, with the potential of turning the greenhouse horticultural sector from a mass energy consumer into a sustainable energy user and producer

Mediating between Services and Learning Activities – the User Perspective

We reflect upon the LADIE project’s experience of migrating a concept of user requirements from the teaching practitioner community to the technical developer community in the light of literature on ‘mediating representations’ and ‘mediating artefacts’. We show that the practical operation of mediating representations is far more complex than previously acknowledged. We suggest that communities need to overlap, allowing reciprocal communication, to migrate concepts via a representation. If they do not, a chain of intermediate representations and communities may be necessary. Finally, we draw a tentative distinction between mediating representations and mediating artefacts, based not in the nature of the resources, but in their mode and context of use