You Know, You Grow

As we have studied the nature of wicked problems and connected with local case studies, our team has come to the conclusion that in order for communities to grow and develop deeper connections, healthier neighborhoods, and happier residents, there must be inclusive dialogue and participatory action. Addressing a neighborhood’s nutritional needs is messy, involving complex social dynamics and disparate stakeholders. Through community connections and dialogic inquiry we have begun to recognize needs related to the local food system. We strive to empower residents to pursue self-directed, neighborhood oriented change. Our team first worked to develop a model of community engagement that can be adapted, copied, and spread to any community setting. The model explained how to conduct inclusive, participatory dialogue that aims to encourage story-telling and camaraderie rather than debate or opposition. Secondly, our team has engaged with several community members over the course of the semester to practice having these dialogic conversations in order to learn, change, and grow as individuals better equipped to understand and progress the dialogue on local food systems. This article synthesizes our findings, describes what we have learned, and offers a model for healthy community conversations that drive locally directed growth

Formal Agent Development: Framework to System

Much work in the field of agent-based systems has tended to focus on either the development of practical applications of agent systems on the one hand, or the development of sophisticated logics for reasoning about agent systems on the other. Our own view is that work on formal models of agent-based systems are valuable inasmuch as they contribute to a fundamental goal of computing of practical agent development. In an ongoing project that has been running for several years, we have sought to do exactly that through the development of a formal framework that provides a conceptual infrastructure for the analysis and modelling of agents and multi-agent systems on the one hand, and enables implemented and deployed systems to be evaluated and compared on the other. In this paper, we describe our research programme, review its achievements to date, and suggest directions for the future

Numerical relativity with characteristic evolution, using six angular patches

The characteristic approach to numerical relativity is a useful tool in evolving gravitational systems. In the past this has been implemented using two patches of stereographic angular coordinates. In other applications, a six-patch angular coordinate system has proved effective. Here we investigate the use of a six-patch system in characteristic numerical relativity, by comparing an existing two-patch implementation (using second-order finite differencing throughout) with a new six-patch implementation (using either second- or fourth-order finite differencing for the angular derivatives). We compare these different codes by monitoring the Einstein constraint equations, numerically evaluated independently from the evolution. We find that, compared to the (second-order) two-patch code at equivalent resolutions, the errors of the second-order six-patch code are smaller by a factor of about 2, and the errors of the fourth-order six-patch code are smaller by a factor of nearly 50.Comment: 12 pages, 5 figures, submitted to CQG (special NFNR issue

Znajek-Damour Horizon Boundary Conditions with Born-Infeld Electrodynamics

In this work, the interaction of electromagnetic fields with a rotating (Kerr) black hole is explored in the context of Born-Infeld (BI) theory of electromagnetism instead of standard Maxwell theory and particularly BI theory versions of the four horizon boundary conditions of Znajek and Damour are derived. Naturally, an issue to be addressed is then whether they would change from the ones given in Maxwell theory context and if they would, how. Interestingly enough, as long as one employs the same local null tetrad frame as the one adopted in the works by Damour and by Znajek to read out physical values of electromagnetic fields and fictitious surface charge and currents on the horizon, it turns out that one ends up with exactly the same four horizon boundary conditions despite the shift of the electrodynamics theory from a linear Maxwell one to a highly non-linear BI one. Close inspection reveals that this curious and unexpected result can be attributed to the fact that the concrete structure of BI equations happens to be such that it is indistinguishable at the horizon to a local observer, say, in Damour's local tetrad frame from that of standard Maxwell theory.Comment: 38 pages, Revtex, typos corrected, accepted for publication in Phys. Rev.

Systems Development using Z Generics

In this paper we present a method for using generic components in formal specifications. This approach results in a flexible generic system description that separates the concerns of structure and data types. The generic specification can be extended and modified in a natural manner, to track requirements as they inevitably evolve during the development process. In addition, the specification can readily be specialised to use more concrete data types without the need for a formal refinement, using explicit generic instantiation. Such generic instantiation also allows operation preconditions to be strengthened; this is not allowed by classic refinement, but it permits a separation of concerns by allowing preconditions relevant to specialised data types to be added only when they become relevant. Here we us

A Formal Approach to Model Emotional Agents Behaviour in Disaster Management Situations

Abstract. Emotions in Agent and Multi-Agent Systems change their behaviour to a more ’natural ’ way of performing tasks thus increasing believability. This has various implications on the overall performance of a system. In particular in situations where emotions play an important role, such as disaster management, it is a challenge to infuse artificial emotions into agents, especially when a plethora of emotion theories are yet to be fully accepted. In this work, we develop a formal model for agents demonstrating emotional behaviour in emergency evacuation. We use state-based formal methods to define agent behaviour in two lay-ers; one that deals with non-emotional and one dealing with emotional behaviour. The emotional level takes into account emotions structures, personality traits and emotion contagion models. A complete formal def-inition of the evacuee agent is given followed by a short discussion on visual simulation and results to demonstrate the refinement of the for-mal model into code