On the development of slime mould morphological, intracellular and heterotic computing devices

The use of live biological substrates in the fabrication of unconventional computing (UC) devices is steadily transcending the barriers between science fiction and reality, but efforts in this direction are impeded by ethical considerations, the field’s restrictively broad multidisciplinarity and our incomplete knowledge of fundamental biological processes. As such, very few functional prototypes of biological UC devices have been produced to date. This thesis aims to demonstrate the computational polymorphism and polyfunctionality of a chosen biological substrate — slime mould Physarum polycephalum, an arguably ‘simple’ single-celled organism — and how these properties can be harnessed to create laboratory experimental prototypes of functionally-useful biological UC prototypes. Computing devices utilising live slime mould as their key constituent element can be developed into a) heterotic, or hybrid devices, which are based on electrical recognition of slime mould behaviour via machine-organism interfaces, b) whole-organism-scale morphological processors, whose output is the organism’s morphological adaptation to environmental stimuli (input) and c) intracellular processors wherein data are represented by energetic signalling events mediated by the cytoskeleton, a nano-scale protein network. It is demonstrated that each category of device is capable of implementing logic and furthermore, specific applications for each class may be engineered, such as image processing applications for morphological processors and biosensors in the case of heterotic devices. The results presented are supported by a range of computer modelling experiments using cellular automata and multi-agent modelling. We conclude that P. polycephalum is a polymorphic UC substrate insofar as it can process multimodal sensory input and polyfunctional in its demonstrable ability to undertake a variety of computing problems. Furthermore, our results are highly applicable to the study of other living UC substrates and will inform future work in UC, biosensing, and biomedicine

Modellierung und Simulation von Gebäudeevakuierung in Notsituationen: Ein Agenten-basierter Ansatz

Evacuation (from Latin ``evacuare'') is the expression which refers to the movement of people getting away from the source of hazard. In general, evacuations are complex in their dynamics due to the variation of the behavioural responses of individuals as part of evacuating crowds. Independent of the type of emergency, evacuation times are a common design measure for guaranteeing personal integrity for people inside of buildings. The accomplishment of design standards regarding evacuation times leads in practise to modifications of architectural design and construction materials of new buildings. Modifications in historic buildings are in contrary limited due to their cultural significance and difficulty of adaptation to modern safety standards. In addition to this, general safety regulations do not cover all aspects required for preventing fatal incidents due to evacuations. In this sense, the study of evacuation dynamics is relevant to the reduction of risk of fatal events. The present thesis proposes a mathematical model for the description of the behavioural dynamics of controlled evacuations based on visual perception. The object-oriented model of PerPedES (Perceiving Pedestrian Evacuation Simulator), which was developed for this thesis, describes the global dynamics of an evacuation by means of individual rules. Walking direction and speed of the modelled pedestrians are obtained based on information derived from a model for visual perception utilising a modified ray-tracing. Within PerPedES, an individual criterion for moving decision motivated by psychological considerations is introduced. The resulting traces of simulated evacuations present similar characteristics to motion patterns described in literature. In particular, arch- and lane-formations, clogging-effect, overtaking- and collision-avoidance manoeuvres. Within the context of risk reduction in the built environment, the presented behavioural model is applied in a case-study. In particular, for the analysis of the vulnerability of the occupants of the Uffizi Gallery in Florence, when pursuing an evacuation. In this thesis, mean evacuation times and individual walking speeds were computed together with the evacuation traces left by the occupant.Evakuierung (vom lateinischen Wort ``evacuare") beschreibt die Bewegung von Menschen weg von einer Gefährdung. Generell sind Evakuierungen komplex in ihrer Dynamik. Dies liegt begründet in der Individualität von menschlichen Reaktionen innerhalb von Menschenmengen. Für die Gewährleistung der Sicherheit von Personen innerhalb von Gebäuden ist die Evakuierungszeit, unabhängig von der Art einer Notsituation, von entscheidender Bedeutung. Die Umsetzung baulicher Standards mit Bezug auf Evakuierungszeiten führt in der Praxis zu Modifikationen an Architektur und Material neuer Gebäude. Modifikationen an historischen Gebäuden können hingegen aufgrund von Denkmalschutzbestimmungen modernen Sicherheitsstandards nicht genüge tragen. Zusätzlich dazu decken allgemeine Sicherheitsregulierungen nicht alle Aspekte ab, die erforderlich sind, um fatale Vorfälle auf Grund von Evakuierungen zu vermeiden. In diesem Sinne ist die Untersuchung der Dynamik von Evakuierungen für die Reduktion solcher fatalen Ereignisse von großer Bedeutung. Die vorliegende Arbeit präsentiert ein mathematisches Modell für die Beschreibung des dynamischen Verlaufs von kontrollierten Evakuierungen, welches auf visueller Wahrnehmung basiert. Das Modell des für diese Arbeit entwickelten Objekt-orientierten Simulators PerPedES (Perceiving Pedestrian Evacuation Simulator) beschreibt die globale Dynamik einer Evakuierung auf Basis von individuellen Zuständen einzelner Modellfußfänger. Die Laufrichtung und Geschwindigkeit dieser Modellfußfänger wird auf Basis eines Modells für visuelle Wahrnehmung ermittelt, welches ein modifiziertes ray-tracing verwendet. Innerhalb von PerPedES wird ein individuelles Kriterium für Bewegungsentscheidungen eingesetzt, welches von psychologischen Betrachtungen motiviert ist. Die aus Simulationen resultierenden Laufwege weisen ähnliche Charakteristika auf, wie in der Literatur dokumentiert. Nachvollzogen werden konnten insbesondere Bogen- und Schlangenformierungen, Verstopfungseffekte und Überholmanöver sowie Kollisionsvermeidung. Im Kontext der Risikoreduktion in Gebäudeumgebungen wurde eine Fallstudie durchgeführt, welche die Vulnerabilität von Besuchern der Uffizi Gallery in Florenz untersucht. Dabei wurden sowohl mittlere Evakuierungszeiten, als auch statistische Verteilung der Laufgeschwindigkeiten während einer Evakuierung und Wegspuren berechnet

Task Allocation in Foraging Robot Swarms:The Role of Information Sharing

Autonomous task allocation is a desirable feature of robot swarms that collect and deliver items in scenarios where congestion, caused by accumulated items or robots, can temporarily interfere with swarm behaviour. In such settings, self-regulation of workforce can prevent unnecessary energy consumption. We explore two types of self-regulation: non-social, where robots become idle upon experiencing congestion, and social, where robots broadcast information about congestion to their team mates in order to socially inhibit foraging. We show that while both types of self-regulation can lead to improved energy efficiency and increase the amount of resource collected, the speed with which information about congestion flows through a swarm affects the scalability of these algorithms

TOWARDS A MODEL FOR ARTIFICIAL AESTHETICS - Contributions to the Study of Creative Practices in Procedural and Computational Systems

Este trabalho propõe o desenvolvimento de um modelo analítico e da terminologia a ele associada para o estudo de artefactos estéticos computacionais. Reconhecendo a presença e uso crescentes dos media computacionais, começamos por estudar como através da remediação eles transformam quantitativamente os media precedentes, e como as suas propriedades procedimentais e computacionais os afectam qualitativamente. Para perceber o potencial criativo e a especificidade dos media computacionais, desenvolvemos um modelo para a sua prática, crítica e análise. Como ponto de partida recorremos à tipologia desenvolvida por Espen Aarseth para o estudo de cibertextos, avaliando a sua adequação à análise de peças ergódicas visuais e audiovisuais, adaptando-a e expandindo-a com novas variáveis e respectivos valores. O modelo é testado através da análise de um conjunto de peças que representam diversas abordagens à criação procedimental e diversas áreas de actividade criativa contemporânea. É posteriormente desenvolvida uma análise de controlo para avaliar a usabilidade e utilidade do modelo, a sua capacidade para a elaboração de classificações objectivas e o rigor da análise. Demonstramos a adequação parcial do modelo de Aarseth para o estudo de artefactos não textuais e expandimo-lo para melhor descrever as peças estudadas. Concluímos que o modelo apresentado produz boas descrições das peças, agrupando-as logicamente, reflectindo afinidades estilísticas e procedimentais entre sistemas que, se estudados com base nas suas propriedades sensoriais ou nas suas estruturas de superfície provavelmente não revelariam muitas semelhanças. As afinidades reveladas pelo modelo são estruturais e procedimentais, e atestam a importância das características computacionais para a apreciação estética das obras. Verificamos a nossa conjectura inicial sobre a importância da procedimentalidade não só nas fases de desenvolvimento e implementação das obras mas também como base conceptual e estética na criação e apreciação artísticas, como um prazer estético

Unmet goals of tracking: within-track heterogeneity of students' expectations for

Educational systems are often characterized by some form(s) of ability grouping, like tracking. Although substantial variation in the implementation of these practices exists, it is always the aim to improve teaching efficiency by creating homogeneous groups of students in terms of capabilities and performances as well as expected pathways. If students’ expected pathways (university, graduate school, or working) are in line with the goals of tracking, one might presume that these expectations are rather homogeneous within tracks and heterogeneous between tracks. In Flanders (the northern region of Belgium), the educational system consists of four tracks. Many students start out in the most prestigious, academic track. If they fail to gain the necessary credentials, they move to the less esteemed technical and vocational tracks. Therefore, the educational system has been called a 'cascade system'. We presume that this cascade system creates homogeneous expectations in the academic track, though heterogeneous expectations in the technical and vocational tracks. We use data from the International Study of City Youth (ISCY), gathered during the 2013-2014 school year from 2354 pupils of the tenth grade across 30 secondary schools in the city of Ghent, Flanders. Preliminary results suggest that the technical and vocational tracks show more heterogeneity in student’s expectations than the academic track. If tracking does not fulfill the desired goals in some tracks, tracking practices should be questioned as tracking occurs along social and ethnic lines, causing social inequality