The Agent-Rule-Class Framework for Multi-Agent Systems

Multi-agent systems have become increasingly mature, but their appearance does not make the traditional OO approach obsolete. On the contrary, OO methodologies can benefit from the principles and tools designed for agent systems. The Agent-Rule-Class (ARC) framework is proposed as an approach that builds agents upon traditional OO system components and makes use of business rules to dictate agent behaviour with the aid of OO components. By modelling agent knowledge in business rules, the proposed paradigm provides a straightforward means to develop agent-oriented systems based on the existing object-oriented systems and offers features that are otherwise difficult to achieve in the original OO systems. The main outcome of using ARC is the achievement of adaptivity. The framework is supported by a tool that ensures agents implement up-to-date requirements from business people, reflecting desired current behaviour, without the need for frequent system rebuilds. ARC is illustrated with a rail track example.

Numerical simulation of the charge balance in an EBIT

The electron beam ions traps (EBITs) are widely used to study highly charged ions (HCIs). In an EBIT, a high energy electron beam collides with atoms and ions to generate HCIs in the trap region. It is important to study the physics in the trap. The atomic processes, such as electron impact ionisation (EI), radiative recombination (RR), dielectronic recombination (DR) and charge exchange (CX), occur in the trap and numerical simulation can give some parameters for design, predict the composition and describe charge state evolution in an EBIT [Phys. Rev. A 43 (199 1) 4861]. We are presently developing a new code, which additionally includes a description of the overlaps between the ion clouds of the various charge-states. It has been written so that it can simulate experiments where various machine parameters (e.g. beam energy and current) can vary throughout the simulation and will be able to use cross- sections either based on scaling laws or derived from atomic structure calculations. An object-oriented method is used in developing the new software, which is an efficient way to organize and write code. (C) 2003 Elsevier Science B.V. All rights reserved.

Numerical simulation of the charge balance and temperature evolution in an electron beam ion trap

A computer code has been developed to simulate and study the evolution of ion charge states inside the trap region of an electron beam ion trap. In addition to atomic physics phenomena previously included in similar codes such as electron impact ionization, radiative recombination, and charge exchange, several aspects of the relevant physics such as dielectronic recombination, ionization heating, and ion cloud expansion have been included for the first time in the model. The code was developed using object oriented concepts with database support, making it readable, accurate, and well organized. The simulation results show a good agreement with various experiments, and give useful information for selection of operating conditions and experiment design.

Soundweaving: Writings on Improvisation

This book consists of eight chapters with writings on improvisation and an introduction by one of the most intriguing improvisers of our generation – Evan Parker.
The initial discussions for this book were carried out during the “Two Thousand + TEN” symposium, which took place on the 6th of November 2010 at the Sonic Arts Research Centre in Belfast. The symposium’s theme was ‘improvisation’. Georgina Born and David Borgo gave keynote addresses, alongside many other excellent speakers, several of who are included in this book.
My contribution is a novel way of editing texts, as I have woven all chapters into an overall piece of writing, interlaced with my own contribution of around 40 pages.

MALTS: A Tool to Simulate Lorentz Transmission Electron Microscopy From Micromagnetic Simulations

Here we describe the development of the MALTS software which is a generalized tool that simulates Lorentz Transmission Electron Microscopy (LTEM) contrast of magnetic nanostructures. Complex magnetic nanostructures typically have multiple stable domain structures. MALTS works in conjunction with the open access micromagnetic software Object Oriented Micromagnetic Framework or MuMax. Magnetically stable trial magnetization states of the object of interest are input into MALTS and simulated LTEM images are output. MALTS computes the magnetic and electric phases accrued by the transmitted electrons via the Aharonov-Bohm expressions. Transfer and envelope functions are used to simulate the progression of the electron wave through the microscope lenses. The final contrast image due to these effects is determined by Fourier Optics. Similar approaches have been used previously for simulations of specific cases of LTEM contrast. The novelty here is the integration with micromagnetic codes via a simple user interface enabling the computation of the contrast from any structure. The output from MALTS is in good agreement with both experimental data and published LTEM simulations. A widely-available generalized code for the analysis of Lorentz contrast is a much needed step towards the use of LTEM as a standardized laboratory technique.

The formal specification of abstract data types and their implementation in Fortran 90: Implementation issues concerning the use of pointers

In this paper we continue our investigation into the development of computational-science software based on the identification and formal specification of Abstract Data Types (ADTs) and their implementation in Fortran 90. In particular, we consider the consequences of using pointers when implementing a formally specified ADT in Fortran 90. Our aim is to highlight the resulting conflict between the goal of information hiding, which is central to the ADT methodology, and the space efficiency of the implementation. We show that the issue of storage recovery cannot be avoided by the ADT user, and present a range of implementations of a simple ADT to illustrate various approaches towards satisfactory storage management. Finally, we propose a set of guidelines for implementing ADTs using pointers in Fortran 90. These guidelines offer a way gracefully to provide disposal operations in Fortran 90. Such an approach is desirable since Fortran 90 does not provide automatic garbage collection which is offered by many object-oriented languages including Eiffel, Java, Smalltalk, and Simula.

Class Responsibility Assignment (CRA) for Use Case Specification to Sequence Diagrams (UC2SD)

Identifying responsibility for classes in object oriented software design phase is a crucial task. This paper proposes an approach for producing high quality and robust behavioural diagrams (e.g. Sequence Diagrams) through Class Responsibility Assignment (CRA). GRASP or General Responsibility Assignment Software Pattern (or Principle) was used to direct the CRA process when deriving behavioural diagrams. A set of tools to support CRA was developed to provide designers and developers with a cognitive toolkit that can be used when analysing and designing object-oriented software. The tool developed is called Use Case Specification to Sequence Diagrams (UC2SD). UC2SD uses a new approach for developing Unified Modelling Language (UML) software designs from Natural Language, making use of a meta-domain oriented ontology, well established software design principles and established Natural Language Processing (NLP) tools. UC2SD generates a well-formed UML sequence diagrams as output.

Exploiting Human Resource Requirements to Infer Human Movement Patterns for Use in Modelling Disease Transmission Systems: An Example from Eastern Province, Zambia

In this research, an agent-based model (ABM) was developed to generate human movement routes between homes and water resources in a rural setting, given commonly available geospatial datasets on population distribution, land cover and landscape resources. ABMs are an object-oriented computational approach to modelling a system, focusing on the interactions of autonomous agents, and aiming to assess the impact of these agents and their interactions on the system as a whole. An A* pathfinding algorithm was implemented to produce walking routes, given data on the terrain in the area. A* is an extension of Dijkstra's algorithm with an enhanced time performance through the use of heuristics. In this example, it was possible to impute daily activity movement patterns to the water resource for all villages in a 75 km long study transect across the Luangwa Valley, Zambia, and the simulated human movements were statistically similar to empirical observations on travel times to the water resource (Chi-squared, 95% confidence interval). This indicates that it is possible to produce realistic data regarding human movements without costly measurement as is commonly achieved, for example, through GPS, or retrospective or real-time diaries. The approach is transferable between different geographical locations, and the product can be useful in providing an insight into human movement patterns, and therefore has use in many human exposure-related applications, specifically epidemiological research in rural areas, where spatial heterogeneity in the disease landscape, and space-time proximity of individuals, can play a crucial role in disease spread.

Gestão de informação académica com base na Web: um sistema de apoio a programas de pós-graduação

Esta dissertação descreve o processo de desenvolvimento de um sistema de informação para a gestão da informação académica de programas de pósgraduação - Sistema WebMaster - que tem como objectivo tornar aquela informação acessível aos utilizadores através da World Wide Web (WWW). Começa-se por apresentar alguns conceitos que se julgam relevantes para a compreensão da problemática dos sistemas de informação em toda a sua abrangência numa determinada organização, particularizando alguns conceitos para o caso das universidades. De seguida reflecte-se sobre os sistemas de informação com base na Web, confrontando-se os conceitos de Web Site (tradicional) e aplicação Web, a nível de arquitectura tecnológica, principais vantagens e desvantagens, fazendo-se, ainda, uma breve referência às principais tecnologias para a construção de soluções com geração dinâmica de conteúdos. Por último representa-se o sistema WebMaster ao longo das suas diferentes etapas de desenvolvimento, desde a análise de requisitos, projecto do sistema, até à fase da implementação. A fase análise de requisitos foi levada a cabo através de um inquérito realizado aos potenciais utilizadores no sentido de identificar as suas necessidades de informação. Com base nos resultados desta fase apresenta-se o projecto do sistema numa perspectiva conceptual, navegacional e de interface de utilizador, fazendo uso da metodologia OOHDM - Object-Oriented Hypermedia Design Method. Finalmente, passa-se à fase da implementação que, com base nas etapas anteriores e nas tecnologias seleccionadas na fase do planeamento, proporciona um espaço interactivo e de troca de informação a todos os interessados da comunidade académica envolvidos em cursos de pós-graduação.

Abstract thinking: a predictor of modelling ability?

In this paper, we describe a study of the abstract thinking skills of a group of students studying object-oriented modelling as part of a Masters course. Abstract thinking has long been considered a core skill for computer scientists. This study is part of attempts to gather evidence about the link between abstract thinking skills and success in the Computer Science discipline. The results of this study show a positive correlation between the scores of the students in the abstract thinking test with the marks achieved in the module. However, the small numbers in the study mean that wider research is needed.

Critical autopoiesis and the materiality of law

Autopoietic theory is increasingly seen as a candidate for a radical theory of law, both in relation to its theoretical credentials and its relevance in terms of new and emerging forms of law. An aspect of the theory that has remained less developed, however, is its material side, and more concretely the theory’s accommodation of bodies, space, objects and their claim to legal agency. The present article reads Luhmann’s theory of autopoietic systems in a radical and material manner, linking it on the one hand to current post-structural theorisations of law and society, and on the other hand extending its ambit to accommodate the influx of material considerations that have been working their way through various other disciplines. The latter comprises both a materialisation of the theory itself and ways of conceptualising the legal system as material through and through. This I do by further developing what I have called Critical Autopoiesis, namely an acentric, topological, post-ecological and posthuman understanding of Luhmann’s theory, that draws on Deleuzian thought, feminist theory, geography, non-representational theory, and new material and object-oriented ontologies. These are combined with some well-rehearsed autopoietic concepts, such as distinction, environment and boundaries; Luhmann’s earlier work on materiality continuum; more recent work on bodies and space; as well as his work on form and medium in relation to art. The article concludes with five suggestions for an understanding of what critical autopoietic materiality might mean for law.

Logics of generalization: Derrida, grammatology and transdisciplinarity

This article seeks to explore some issues regarding the different modes of generality at stake in the formation of transdisciplinary concepts within the production of ‘theory’ in the humanities and social sciences. Focused around Jacques Derrida’s seminal account of ‘writing’ in his 1967 book Of Grammatology, the article outlines what it defines as a logic of generalization at stake in Derrida’s elaborations of a quasi-transcendental ‘inscription in general’. Starting out from the questions thereby raised about the relationship between such forms of generality and those historically ascribed to philosophy, the article concludes by contrasting Derrida’s generalized writing with more recent returns to ‘metaphysics’ in the work of Bruno Latour and others. Against the immediately ‘ontological’ orientation of much recent ‘new materialist’ or ‘object-oriented’ thought, the article argues for the necessity of ‘different levels of writing in general’ through a continual folding back of absolute generalization into historically specific disciplinary crossings and exchanges; something suggested by but never really developed in Derrida’s own work.

Modelo SIG para apoio à análise de sistemas de transportes e usos do solo

Dissertação de natureza científica para obtenção do grau de Mestre em Engenharia Civil

Modelos de simulação em MATSim aplicados à análise de sistemas de transporte

Dissertação para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Vias de Comunicação e Transportes