Les travaux réalisés pendant mon doctorat répondent à la problématique de la simulation physique, en temps interactif, du comportement d'objets déformables soumis à des changements topologiques. Mes travaux ont abouti à la définition d'un nouveau modèle unifié couplant un modèle topologique complet et un modèle physique, pour la simulation physique d'objets déformables décomposés en éléments surfaciques comme volumiques, tout en réalisant pendant cette simulation des changements topologiques comme la découpe ou la subdivision locale d'un élément du maillage. Cette dernière opération a permis de proposer une méthode adaptative où les éléments du maillage sont raffinés selon un critère géométrique au cours de la simulation. Nous avons fait le choix des cartes combinatoires et plus particulièrement celui des complexes cellulaires linéaires, comme modèle topologique de notre modèle unifié. Ils ont l'avantage d'être génériques par rapport à la dimension de l'objet représenté mais également par rapport à la topologie des cellules en lesquelles l'objet est décomposé. Le système masses-ressort a, quant à lui, été choisi comme modèle physique de notre modèle unifié. L'avantage de ce dernier réside dans la simplicité de ses équations, son implémentation intuitive, son interactivité et sa facilité à gérer les changements topologiques. Enfin, la définition d'un modèle unifié nous a permis de proposer un modèle évitant la redondance d'informations et facilitant la mise à jour de ces dernières suite à des changements topologiques / The work made during my PhD, respond to the problematic of physical simulation of the behavior of deformable objects subject to topological changes in interactive time. My work resulted in the definition of a new unified model coupling a complete topological model and a physical model for physical simulation of deformable objects decomposed in surface as volume elements, while performing during this simulation topological changes such as cutting or subdivision local of a mesh element. This operation allowed us to propose an adaptive method where mesh elements are refined during the simulation according to a geometric criterion. For the topological model of our unified model, we made the choice of combinatorial maps and more particularly linear cellular complexes. Their main advantage of the latter is the simplicity of its equations, its intuitive implementation, its interactivity and its ease to handle topological changes. Finally, the definition of a unified model allowed us to propose a model avoiding duplication of information and facilitate the update after topological changes

La miniaturisation des composants, qui s’est engagée depuis l’avènement de l’électronique il y a plus de 50 ans, atteint aujourd’hui la dimension nanométrique, ouvrant la porte aux phénomènes quantiques. Ultime étape de cette miniaturisation, la boîte quantique, dans laquelle les électrons sont confinés dans les trois directions de l’espace, présente des propriétés remarquables, telles que l’augmentation du gap entre la bande de conduction et la bande de valence, ou la discrétisation des niveaux d’énergies. Autre conséquence du confinement, la forte interaction électron-électron régnant au sein de la boîte conduit à une énergie de charge importante, susceptible de bloquer l'entrée d'un électron dans la boîte sans apport d'énergie extérieur. Ce phénomène de blocage des charges est appelé blocage de Coulomb. Le transistor à un électron (SET), dispositif élémentaire tirant profit de ce phénomène, est pressenti pour quelques applications, comme la réalisation de fonctions logiques ou la détection de charge. Parmi les domaines concernés, la thermoélectricité, c’est-à-dire la possibilité de créer du courant électrique à partir d’une différence de température, s’intéresse de près aux dispositifs à un électron en raison de leurs niveaux d’énergie discrets qui conduisent à une très faible conductivité thermique. Ce travail présente le simulateur SENS (Single-Electron Nanodevice Simulation) développé dans l’équipe, et dont j’ai réalisé la partie destinée à la simulation du SET. Il s’appuie sur la résolution des équations couplées de Poisson et Schrödinger, nécessaire à la détermination des fonctions d’onde dans la boîte de silicium, elles-mêmes dépendantes des tensions appliquées aux électrodes. Les fréquences de transition tunnel sont ensuite calculées par la règle d’or de Fermi. L’étude approfondie du courant dans les SET permet d’extraire des diagrammes de stabilité en diamant, et démontre l’importance de paramètres tels que la taille de l’îlot, la dimension des barrières tunnel, la température et le nombre d’électrons occupant la boîte. L’étude du courant électronique et du courant de chaleur en présence d’une différence de température aux électrodes du SET est également faite pour juger de la pertinence de l’utilisation d’un SET en tant que générateur thermoélectrique, mais aussi comme étalon pour déterminer le coefficient Seebeck. Enfin, une étude du bruit de grenaille dans la double-jonction tunnel (SET sans la grille) est faite, démontrant le fort lien entre taux de transfert tunnel et bruit. En particulier, selon l’évolution des taux des transferts tunnel d’entrée et de sortie de l'îlot, pour un nombre d’électrons supérieur 2, il est possible d’observer une augmentation importante du bruit, qui devient alors super-Poissonien. L’étude de l’influence des paramètres géométriques démontre que le bruit de grenaille dépend essentiellement de la différence des épaisseurs de barrière tunnel. / After a continuous reduction which has begun 50 years ago, the feature size of electronic devices has now reached the nanometer scale, opening the door to quantum phenomena. The final stage of this miniaturization, the quantum dot, in which the electrons are confined in all three directions of space, has remarkable properties, such as an increase of the bandgap between the conduction band and the valence band, and the discretization of energy levels. Another consequence of confinement, the strong electron-electron interaction occurring in the dot induces a significant charging energy which may prevent an electron entering the dot if an external energy is not provided to the system. This charge blocking is called Coulomb blockade. The single electron transistor (SET), the elementary device taking advantage of Coulomb blockade, is slated for some applications, such as the realization of digital functions or charge sensors. Among the areas concerned, the thermoelectricity, i.e., the possibility of creating an electrical current from a temperature gradient, is very interested in single-electron devices due to their discrete energy levels which lead to a very low thermal conductivity.This thesis presents the simulator SENS (Single-Electron Nanodevice Simulation) developed in the team and the part I have developed specifically for the simulation of SET. It is based on a 3D solver of Poisson and Schrödinger coupled equations, necessary for the determination of the wave functions in the case of silicon, and dependent on voltages applied to the electrodes. Tunnel transfer rates are then calculated by Fermi's golden rule. In-depth study of the current in the SETs gives access to diamond stability diagrams, and demonstrates the importance of parameters such as dot size, tunnel the barriers thicknesses, the temperature and the number of electrons occupying the dot. The study of the electron current and the heat flow in the presence of a temperature difference at the electrodes of an SET is also made to consider the suitability of the use of an SET as thermoelectric generator, but also as a standard for determining the Seebeck coefficient.Finally, a study of shot noise in double-tunnel junction (SET without the gate) is made, demonstrating the strong link between tunnel transfer rate and shot noise. In particular, according to the evolution of in- and out – tunnel transfer rates, for a number of electrons in the dot greater than 2, it is possible to observe a significant increase in noise, which becomes super-Poissonian. The study of the influence of geometrical parameters shows that the shot noise depends mainly on the difference of the tunnel barrier thicknesses.

In this thesis a custom embedded system and control software developed for an Automated Storage and Retrieval System (AS/RS) which is based on the Computer Integrated Manufacturing Laboratory (CIMLAB) located in the Department of Mechanical Engineering, Middle East Technical University. Primary objective of this study is AS/RSs related control rules can be applicable to the current physical system. The secondary objective is determined as developing the control system in a flexible way that allows adding new equipments to the system and configuring parts of the system. Two types of control board are manufactured and also boards&rsquo / firmware and computer software are developed. These two boards communicate with computer one at a time. Some AS/RS related control rules are implemented at the control software. According to these rules the control software assigns tasks to the related board. Also the control software records necessary information in order to measure the performance of the AS/RS. Several control rules as storage assignment, dwell point and sequencing of storage and retrieval order rules are applicable to the AS/RS without need for low level programming. Because of the physical limitation, batching rules cannot be applied to the current system. Also a graphical user interface is developed for using the system easily and observing the real time status of the system equipments. Two experiments are designed and run in order to show flexibility of the control system. Different control rules applied to each of the experiment. Experiment results put forth the control system was quite successful in meeting the objectives.

Les transmissions radio à longue portée et basse énergie ouvrent de nouveaux champs d'application pour les capteurs, en particulier pour la surveillance de l'environnement. Le protocole radio LoRa permet, par exemple, de connecter des capteurs à une distance pouvant aller jusqu'à dix kilomètres en ligne de visée. Cependant, la grande surface couverte amène plusieurs difficultés, telles que le placement spatial en regard de la topologie géographique, ou la variabilité de la latence des communications. Le positionnement dans I'environnement comporte également des contraintes liées à I'intérêt des points de mesure du phénomène physique. Les critères de conception de ces réseaux tranchent donc avec les méthodes existantes (disques) quand on s'attaque aux terrains complexes. Cette thèse décrit des techniques de simulation basées sur I'analyse géographique cellulaire pour calculer les couvertures radio à longue portée et déduire les caractéristiques radios dans ces situations. Comme la propagation radio n'est qu'un cas particulier de phénomènes physiques, on montre qu'une approche unifiée cellulaire permet de caractériser beaucoup de comportements physiques potentiels. Le cas des fortes pluies et des inondations est étudié. L'analyse de la géographie est réalisée en utilisant des outils de segmentation pour produire des systèmes cellulaires qui sont à leur tour traduits en code pour des calculs de haute performance. La thèse fournit des résultats d'expériences de terrain complexes pratiques en utilisant LoRa, permettant de qualifier l'exactitude de la simulation des couvertures, et les caractéristiques d'ordonnancement des communications. Nous produisons des tables de performance pour les simulations sur les unités de traitement graphique (GPUs) qui montrent que le choix d'une algorithmique parallèle est pertinent sur ces problèmes. / Long-range radio transmissions open new sensor application fields, in particular for environment monitoring. For example, the LoRa radio protocol enables to connect remote sensors at distance as long as ten kilometers in a line-of-sight. However, the large area covered also brings several difficulties, such as the placement of sensing devices in regard to topology in geography, or the variability of communication latency. Sensing the environment also carries constraints related to the inlerest of sensing points in relation with a physical phenomenon. Thus criteria for designs are evolving a lot from the existing methods, especially in complex terrains. This thesis describes simulation techniques based on geography analysis to compute long-range radio coverages and radio characteristics in these situations. As radio propagation is just a particular case of physical phenomena, it is shown how a unified approach also allows to characterize the behavior of potential physical risks. The case of heavy rainfall and flooding is investigated. Geography analysis is achieved using segmentation tools to produce cellular systems which are in turn translated into code for high-þerformance computations. The thesis provides results from practical complex terrain experiments using LoRa which confirm the accuracy of the simulation, and scheduling characteristics for sample networks. Performance tables are produced for these simulations on current Graphics Processing Units (GPUs).

[pt] Os aços inoxidáveis duplex (AID) possuem uma estrutura mista de Delta-ferrita e Gamma-austenita em frações de volume aproximadamente iguais e combinam muitas das propriedades benéficas das duas fases, a ferrita fornece alta resistência mecânica e resistência à corrosão, enquanto que a austenita aumenta a ductilidade e a resistência à corrosão uniforme. Uma vantagem dos AID é a resistência à trincas de solidificação, que está associado à soldagem. Pela combinação de propriedades, esses aços são amplamente utilizados na indústria de equipamentos químicos, petróleo e gás, plantas de dessalinização, controle de poluição, usinas elétricas e, mais recentemente, em aplicações off-shore como na extração de petróleo em águas profundas. No entanto, a exposição destes aços a temperaturas elevadas entre 600 graus celsius e 1000 graus celsius, que ocorre durante a soldagem por fusão resulta na precipitação de diferentes compostos, sendo os mais frequentemente encontrados a fase sigma, a fase x, os nitretos de cromo e os carbonetos que reduzem tanto a resistência mecânica quanto a resistência a corrosão. Este trabalho teve como objetivo simular fisicamente as microestruturas da zona termicamente afetada (ZTA) dos AIDs UNS S32304, S32205 e S32750. De modo a obter diferentes ZTAs foi utilizado o simulador termo-mecânico Gleeble, por meio deste simulador foram aplicados vários aportes de calor que permitiram avaliar a evolução microestrutural e as propriedades mecânicas destas zonas. As temperaturas utilizadas nas simulações físicas foram determinadas por meio do software Thermo-Calc assegurando assim as faixas de transformações microestruturais. A temperatura de pico utilizada foi de 1350 graus celsius por 2 segundos; seguida de resfriamento em acordo com o modelo Rykalin-2D, onde um grupo de amostras sofreu resfriamento até alcançar a temperatura de 500 graus celsius seguido de uma têmpera em água e um outro grupo até 250 graus celsius seguido de uma têmpera. Este procedimento foi adotado de modo a identificar a influência dos aportes de calor e as taxas de resfriamento na frações volumétricas das fases obtidas. Foi observado um aumento da fração volumétrica da austenita, assim como um aumento do tamanho de grão da ferrita e um crescimento nos grãos da austenita, em função do aumento do aporte de calor durante as simulações físicas das ZTAs. Estas variações microestruturais ocasionaram o decréscimo da resistência mecânica nos três AID avaliados quando comparados ao respectivo metal de base. / [en] The duplex stainless steels (DSS) have a structure that consist of approximately equivalent amounts of delta-austenita and gamma-ferrite, exhibit excellent properties combinations of both phases. DSS combine the high strength and resistance to stress corrosion cracking come from ferrite, whereas the austenite phase influences ductility and uniform corrosion resistance. The advantage of DSS is solidification cracking resistance; it is associated to welding processes. The application of DSS have being increasingly used as structural material in various industrial sectors, such as chemical, petrochemical, pulp and paper, power generation, desalination, oil and gas, for the constructions in marine and chemical industries and most recently for manufacturing components used in off-shore oil platforms for oil extraction in deep water. However, the exposure of these steels to high temperatures between 600 celsius degrees and 1000 celsius degrees, which occurs during fusion welding results in different compounds precipitation, the most frequently encountered being the sigma phase, the X phase, the chromium nitrides and carbides which reduce both mechanical strength and corrosion resistance. The aim of this work was to simulate physically the Heat Affected Zone (HAZ) microstructures in DSS UNS S32304, S32205 and S32750. In order to obtain different HAZ the Gleeble system was used. Several heat inputs were applied through this simulator, which allowed evaluate the microstructural evolution and the mechanical properties of these zones. The temperatures used in physical simulations were determined by Thermo-Calc Software, this supplied the microstructural transformations temperature ranges. The peak temperature used was 1350 celsius degrees for 2 seconds; followed by cooling in accordance with the Rykalin-2D model; one sample set was cooled to 500 celsius degrees followed by water quenching, and the second sample set was cooled to 250 celsius degrees followed by quenching. This procedure was adopted in order to identify the effect of the final temperature on the phases volume fraction obtained. An increase in the austenite volume fraction, as well as an increase in the ferrite grain size and a widening in the austenite grains, due to the increase of the heat input during the physical simulations of the ZTAs was observed. These microstructural variations caused the tensile strength and Yield strength decreasing in HAZ of DSS evaluated when these zones were compared to the respective base metal.

Ce travail vise à étudier la robustesse de trois générations de MOSFET SiC de puissance (Silicon Carbide Metal Oxide Semiconductor Field E_ect Transistors). Plusieurs approches sont suivies : la caractérisation électrique, la modélisation physique, les tests de vieillissement et la simulation physique. Un modèle compact basé sur une nouvelle méthode d'extraction de paramètres et sur les résultats de caractérisation électrique est présenté. Les paramètres extraits du modèle (tensionde seuil, transconductance de la région de saturation et paramètre du champ électrique transverse) sont utilisés pour analyser avec précision le comportement statique de trois générations de MOSFET SiC. La robustesse de ces dispositifs sont étudiées par deux tests : le test HTRB (High Temperature Reverse Bias) et le test ESD (Electrostatic Discharge). Une simulation physique est réalisée pour comprendre l'impact de la température et des paramètres physiques sur les caractérisations électriques des MOSFETs SiC. / This work aims to investigate the robustness of three generations of power SiC MOSFETs (SiliconCarbide Metal Oxide Semiconductor Field E_ect Transistors). Several approaches are followed :electrical characterization, device modeling, ageing tests and physical simulation. An improvedcompact model based on an accurate parameters extraction method and one electrical characterization results is presented. The parameters extracted precisely from the model (thresholdvoltage, saturation region transconductance...) are used to accurately analyze the static behaviorof two generations of SiC MOSFETs. The robustness of these devices are investigated bytwo tests : HTRB (High Temperature Reverse Bias) stress and an ESD (Electrostatic Discharge)stress. Physical simulation is conducted to understand the impact of the temperature and thephysical parameters on the device electrical characterizations.

The topic of this dissertation is the anatomical, psychological, and cultural examination of a human face in order to effectively construct an anatomy-driven 3D virtual face customization and action model. In order to gain a broad perspective of all aspects of a face, theories and methodology from the fields of art, engineering, anatomy, psychology, and cultural studies have been analyzed and implemented. The computer generated facial customization and action model were designed based on the collected data. Using this customization system, culturally-specific attractive face in Korean popular culture, “kot-mi-nam (flower-like beautiful guy),” was modeled and analyzed as a case study. The “kot-mi-nam” phenomenon is overviewed in textual, visual, and contextual aspects, which reveals the gender- and sexuality-fluidity of its masculinity. The analysis and the actual development of the model organically co-construct each other requiring an interwoven process. Chapter 1 introduces anatomical studies of a human face, psychological theories of face recognition and an attractive face, and state-of-the-art face construction projects in the various fields. Chapter 2 and 3 present the Bezier curve-based 3D facial customization (BCFC) and Multi-layered Facial Action Model (MFAF) based on the analysis of human anatomy, to achieve a cost-effective yet realistic quality of facial animation without using 3D scanned data. In the experiments, results for the facial customization for gender, race, fat, and age showed that BCFC achieved enhanced performance of 25.20% compared to existing program Facegen , and 44.12% compared to Facial Studio. The experimental results also proved the realistic quality and effectiveness of MFAM compared with blend shape technique by enhancing 2.87% and 0.03% of facial area for happiness and anger expressions per second, respectively. In Chapter 4, according to the analysis based on BCFC, the 3D face of an average kot-mi-nam is close to gender neutral (male: 50.38%, female: 49.62%), and Caucasian (66.42-66.40%). Culturally-specific images can be misinterpreted in different cultures, due to their different languages, histories, and contexts. This research demonstrates that facial images can be affected by the cultural tastes of the makers and can also be interpreted differently by viewers in different cultures.

Cette thèse porte principalement sur la caractérisation électrique et la modélisation physique d'éléments mémoires émergents de type OxRRAM (Oxide Resistive Random Access Memory) intégrant soit un oxyde de nickel, soit un oxyde de hafnium. Une fois la maturité technologique atteinte, ce concept de mémoire est susceptible de remplacer la technologie Flash qui fait encore figure de référence. Les principaux avantages de la technologie OxRRAM reposent sur une très bonne compatibilité avec les filières CMOS, un faible nombre d'étapes de fabrication, une grande densité d'intégration et des performances attractives en termes de fonctionnement. Le premier objectif de ce travail concerne le diélectrique employé dans les cellules. Il s'agit d'apporter des éléments factuels permettant d'orienter un choix technologique sur la méthode d'élaboration de l'oxyde de nickel (oxydation thermique ou pulvérisation cathodique réactive) puis d'évaluer les performances de cellules à base d'oyxde de hafnium. Le second objectif est d'approfondir la compréhension des mécanismes physiques responsables du changement de résistance des dispositifs mémoire par une approche de modélisation physique des phénomènes opérant lors des phases d'écriture et d'effacement, sujet encore largement débattu dans la communauté scientifique. Le troisième objectif de cette thèse est d'évaluer, par le biais de caractérisations électriques, les phénomènes parasites intervenant dans les éléments mémoires de type 1R (élément résistif sans dispositif d'adressage) et, en particulier, la décharge capacitive apparaissant lors de leur programmation (opérations d'écriture). / This work is focused on the electrical characterization and physical modeling of emerging OxRRAM memories (Oxide Resistive Random Access Memory) integrating nickel or hafnium oxide. After reaching maturity, this memory concept is likely to replace the Flash technology which is still a standard in the CMOS industry. The main advantages of resistive memories technology is their good compatibility with CMOS processes, a small number of manufacturing steps, a high integration density and their attractive performances in terms of memory operation. The first objective of this thesis is to provide enough informations allowing to orientate the elaboration process of the active nickel oxide layer (thermal oxidation, reactive sputtering) then to compare the performances of the fabricated cells with devices featuring a hafnium oxide layer. The second objective is to understand the physical mechanisms responsible of the device resistance change. A physical model is proposed allowing to apprehend SET and RESET phenomenon in memory devices, subject which is still widely debated in the scientific community. The third objective of this thesis is to evaluate electrical parasitic phenomenon observed in 1R-type memory elements (resistive element without addressing device), in particular the parasitic capacitance appearing during cell programming (writing operation).

Made available in DSpace on 2015-03-05T13:58:27Z (GMT). No. of bitstreams: 0 Previous issue date: 10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo desta dissertação é propor, testar e avaliar o uso de técnicas de Aprendizado de Máquina (ML) na configuração automática do controle do caminhar de robôs com pernas. Para que este objetivo fosse atingido, um extensa pesquisa de técnicas do estado da arte foi realizada e descrita neste trabalho. Esta pesquisa permitiu a elaboração do modelo proposto, chamado de LegGen, que foi implementado em um protótipo. O protótipo modelo em questão permite a utilização de vários tipos de robôs, compostos de quatro, seis ou mais patas, e além disto permite a evolução da morfologia dos robôs. Utilizando o protótipo, é possível a realização de experimentos com robôs autônomos dotados de pernas, em um ambiente virtual tridimensional realístico, através de simulações baseadas em física. Foi utilizada a biblioteca ODE (Open Dynamics Engine) para a simulação de corpos rígidos e articulações, permitindo assim simular forças agindo nas articulações (atuadores), gravidade e colisões, entre outras propriedades físicas dos / The main goal of this dissertation is to propose, to test and to evaluate the use of Machine Learning (ML) techniques in the automatic con_guration of the gait control in legged robots. In order to achieve this goal, an extensive research about state-of-the-art techniques was accomplished and they are described in this work. This research allowed the development of the proposed model, called LegGen, which was implemented in a prototype. The proposed model allows the use of several different robot models with four, six or more paws. Besides that, the prototype allows also to study the robot's morphology evolution. The implemented prototype allows to accomplish experiments with autonomous legged robots, in a realistic three-dimensional virtual environment, through physics based simulations. The ODE (Open Dynamics Engine) software library was used in the physical simulation of rigid bodies and articulations, allowing to simulate forces acting in the articulations (actuators), gravity and collisions, among other

Swarm robotics is the study of developing and controlling large groups of robots. Collectives of robots possess advantages over single robots such as being robust to mission failures due to single-robot errors. Experimental research in swarm robotics is currently limited by swarm robotic technology. Current swarm robotic systems are either small groups of sophisticated robots or large groups of simple robots due to manufacturing overhead, functionality-cost dependencies, and their need to avoid collisions, amongst others. It is therefore useful to develop a swarm robotic system that is easy to manufacture, that utilises its sensors beyond standard usage, and that allows for physical interactions. In this work, I introduce a new type of low-friction locomotion and show its first implementation in the HoverBot system. The HoverBot system consists of an air-levitation and magnet table, and a HoverBot agent. HoverBots are levitating circuit boards which are equipped with an array of planar coils and a Hall-effect sensor. HoverBot uses its coils to pull itself towards magnetic anchors that are embedded into a levitation table. These robots consist of a Printed Circuit Board (PCB), surface mount components, and a battery. HoverBots are easily manufacturable, robots can be ordered populated; the assembly consists of plugging in a battery to a robot. I demonstrate how HoverBot's low-cost hardware can be used beyond its standard functionality. HoverBot's magnetic field readouts from its Hall-effect sensor can be associated with successful movement, robot rotation and collision measurands. I build a time series classifier based on these magnetic field readouts, I modify and apply signal processing techniques to enable the online classification of the time-variant magnetic field measurements on HoverBot's low-cost microcontroller. This method allows HoverBot to detect rotations, successful movements, and collisions by utilising readouts from its single Hall-effect sensor. I discuss how this classification method could be applied to other sensors and demonstrate how HoverBots can utilise their classifier to create an occupancy grid map. HoverBots use their multi-functional sensing capabilities to determine whether they moved successfully or collided with a static object to map their environment. HoverBots execute an "explore-and-return-to-nest" strategy to deal with their sensor and locomotion noise. Each robot is assigned to a nest (landmark); robots leave their nests, move n steps, return and share their observations. Over time, a group of four HoverBots collectively builds a probabilistic belief over its environment. In summary, I build manufacturable swarm robots that detect collisions through a time series classifier and map their environment by colliding with their surroundings. My work on swarm robotic technology pushes swarm robotics research towards studies on collision-dependent behaviours, a research niche that has been barely studied. Collision events occur more often in dense areas and/or large groups, circumstances that swarm robots experience. Large groups of robots with collision-dependent behaviours could become a research tool to help invent and test novel distributed algorithms, to understand the dependencies between local to global (emergent) behaviours and more generally the science of complex systems. Such studies could become tremendously useful for the execution of large-scale swarm applications such as the search and rescue of survivors after a natural disaster.