Pedestrians moving in dark: Balancing measures and playing games on lattices

We present two conceptually new modeling approaches aimed at describing the motion of pedestrians in obscured corridors: * a Becker-D\"{o}ring-type dynamics * a probabilistic cellular automaton model. In both models the group formation is affected by a threshold. The pedestrians are supposed to have very limited knowledge about their current position and their neighborhood; they can form groups up to a certain size and they can leave them. Their main goal is to find the exit of the corridor. Although being of mathematically different character, the discussion of both models shows that it seems to be a disadvantage for the individual to adhere to larger groups. We illustrate this effect numerically by solving both model systems. Finally we list some of our main open questions and conjectures

Multi-Agent Fitness Functions For Evolutionary Architecture

The dynamics of crowd movements are self-organising and often involve complex pattern formations. Although computational models have recently been developed, it is unclear how well their underlying methods capture local dynamics and longer-range aspects, such as evacuation. A major part of this thesis is devoted to an investigation of current methods, and where required, the development of alternatives. The main purpose is to utilise realistic models of pedestrian crowds in the design of fitness functions for an evolutionary approach to architectural design. We critically review the state-of-the-art in pedestrian and evacuation dynamics. The concept of 'Multi-Agent System' embraces a number of approaches, which together encompass important local and longer-range aspects. Early investigations focus on methods-cellular automata and attractor fields-designed to capture these respective levels. The assumption that pattern formations in crowds result from local processes is reflected in two dimensional cellular automata models, where mathematical rules operate in local neighbourhoods. We investigate an established cellular automata and show that lane-formation patterns are stable only in a low-valued density range. Above this range, such patterns suddenly randomise. By identifying and then constraining the source of this randomness, we are only able to achieve a small degree of improvement. Moreover, when we try to integrate the model with attractor fields, no useful behaviour is achieved, and much of the randomness persists. Investigations indicate that the unwanted randomness is associated with 2-lattice phase transitions, where local dynamics get invaded by giant-component clusters during the onset of lattice percolation. Through this in-depth investigation, the general limits to cellular automata are ascertained-these methods are not designed with lattice percolation properties in mind and resulting models depend, often critically, on arbitrarily chosen neighbourhoods. We embark on the development of new and more flexible methodologies. Rather than treating local and global dynamics as separate entities, we combine them. Our methods are responsive to percolation, and are designed around the following principles: 1) Inclusive search provides an optimal path between a pedestrian origin and destination. 2) Dynamic boundaries protect search and are based on percolation probabilities, calculated from local density regimes. In this way, more robust dynamics are achieved. Simultaneously, longer-range behaviours are also specified. 3) Network-level dynamics further relax the constraints of lattice percolation and allow a wider range of pedestrian interactions. Having defined our methods, we demonstrate their usefulness by applying them to lane-formation and evacuation scenarios. Results reproduce the general patterns found in real crowds. We then turn to evolution. This preliminary work is intended to motivate future research in the field of Evolutionary Architecture. We develop a genotype-phenotype mapping, which produces complex architectures, and demonstrate the use of a crowd-flow model in a phenotype-fitness mapping. We discuss results from evolutionary simulations, which suggest that obstacles may have some beneficial effect on crowd evacuation. We conclude with a summary, discussion of methodological limitations, and suggestions for future research

Common metrics for cellular automata models of complex systems

The creation and use of models is critical not only to the scientific process, but also to life in general. Selected features of a system are abstracted into a model that can then be used to gain knowledge of the workings of the observed system and even anticipate its future behaviour. A key feature of the modelling process is the identification of commonality. This allows previous experience of one model to be used in a new or unfamiliar situation. This recognition of commonality between models allows standards to be formed, especially in areas such as measurement. How everyday physical objects are measured is built on an ingrained acceptance of their underlying commonality. Complex systems, often with their layers of interwoven interactions, are harder to model and, therefore, to measure and predict. Indeed, the inability to compute and model a complex system, except at a localised and temporal level, can be seen as one of its defining attributes. The establishing of commonality between complex systems provides the opportunity to find common metrics. This work looks at two dimensional cellular automata, which are widely used as a simple modelling tool for a variety of systems. This has led to a very diverse range of systems using a common modelling environment based on a lattice of cells. This provides a possible common link between systems using cellular automata that could be exploited to find a common metric that provided information on a diverse range of systems. An enhancement of a categorisation of cellular automata model types used for biological studies is proposed and expanded to include other disciplines. The thesis outlines a new metric, the C-Value, created by the author. This metric, based on the connectedness of the active elements on the cellular automata grid, is then tested with three models built to represent three of the four categories of cellular automata model types. The results show that the new C-Value provides a good indicator of the gathering of active cells on a grid into a single, compact cluster and of indicating, when correlated with the mean density of active cells on the lattice, that their distribution is random. This provides a range to define the disordered and ordered state of a grid. The use of the C-Value in a localised context shows potential for identifying patterns of clusters on the grid

Physics of traffic Gridlock in a city: a study of the spreading of traffic jams on urban street networks

Abstract. Traffic congestion has profound and varied impacts on modern society, yet characterizing on a city scale the transition that gives rise to the congestion remains an elusive task. The challenge lies in understanding the role of the interplay between topology and spatial dynamics in this traffic phenomenon. In this thesis we combine cellular automata modelling with analysis tools from statistical physics to study the emergence of congestions at road (street), grid (neighbourhood) and network (city) levels. At street level, we shown for at least two traffic cellular automata that implementing a simple Monte Carlo exploration of the driving rules reproduces the fundamental diagram of a single road segment. Next, by applying tools of percolation theory, we unveiled the underlying mechanism of jamming process in the Biham-Middleton Levine model, i.e., a paradigmatic model for car traffic, both on square and honeycomb grids, solving a puzzle of more than a decade on the origin of the intermediate states of this model on square grids and pointing out the relevance of both asymmetry and the underlying grid on the model's behaviour. Finally, we used the origin-destination matrices obtained from mobile phone data to simulate car by car the traffic on the detailed road network of five large cities: Rio, Boston, San Francisco bay, Porto and Lisbon. We found at this network level that the characteristic recovery time the system takes to unload is proportional to the fraction of road infrastructure being used and the mean travel time on all trips. In addition, we study the emergence of congestion when the number of cars increases by keeping the trip distributions and street capacities unchanged. Our last findings strongly support the notion that the transitions to urban traffic gridlock resemble the direct percolation universality class and can be approached with the framework of non-equilibrium phase transitions. Our work illustrates the power of a computational description at the level of each car with the solid theoretical framework of statistical physics to analyze the origins and behaviour or vehicular traffic congestion.La congestión vehícular tiene un impacto profundo y diverso en la sociedad actual. Sin embargo, caracterizar a nivel de ciudad la transición que da lugar a la congestión ha sido una tarea inalcanzable. El problema se centra en la dificultad para entender la interacción que existe entre la topología de la red y la dinámica espacial del flujo vehícular. En esta tesis se combina el modelamiento por autómatas celulares con herramientas de la física estadística para estudiar la formación de la congestión a escala de calle, de malla regular y de red real de calles. A nivel de calle, mostramos que para al menos dos modelos de autómata celular, una exploración por Monte Carlo de las reglas de manejo permite reproducir el diagrama fundamental de una calle. A nivel de mallas regulares, el modelo Biham-Middleton-Levine (BML) es el paradigma de los estudios de tráfico vehícular. Aplicando las herramientas de la Teor\'ia de Percolación, logramos desentrañar los mecanismos de formación de atascos en este modelo, ya sea sobre mallas cuadradas o tipo panal. Logramos entonces resolver el misterio del origen los llamados estados intermedios en el BML en mallas cuadradas. Finalmente, usamos las matrices origen destino obtenidas a partir de datos de telefonía móvil para simular el tráfico vehícular de cinco ciudades alrededor del mundo: Río de Janeiro, Boston, la bahía de San Francisco, Porto y Lisboa. A este nivel de red de ciudad, encontramos que el tiempo de recuperación característico de cada ciudad es proporcional a la fracción de infraestructura utilizada y el tiempo promedio de viaje. Adicionalmente, incrementando la demanda, estudiamos el colapso vehícular en redes de ciudad bajo el marco de transiciones de fase fuera del equilibrio. Nuestros resultados muestran características similares a las observados en los modelos dentro de la clase de universalidad de percolación dirigida (DP). Nuestro trabajo ilustra cómo una descripción computacional a nivel de vehículo junto con las herramientas de la física estadística permite analizar y comprender los orígenes y el comportamiento de la congestión vehícular.Doctorad

KINE[SIS]TEM'17 From Nature to Architectural Matter

Kine[SiS]tem – From Kinesis + System. Kinesis is a non-linear movement or activity of an organism in response to a stimulus. A system is a set of interacting and interdependent agents forming a complex whole, delineated by its spatial and temporal boundaries, influenced by its environment. How can architectural systems moderate the external environment to enhance comfort conditions in a simple, sustainable and smart way? This is the starting question for the Kine[SiS]tem’17 – From Nature to Architectural Matter International Conference. For decades, architectural design was developed despite (and not with) the climate, based on mechanical heating and cooling. Today, the argument for net zero energy buildings needs very effective strategies to reduce energy requirements. The challenge ahead requires design processes that are built upon consolidated knowledge, make use of advanced technologies and are inspired by nature. These design processes should lead to responsive smart systems that deliver the best performance in each specific design scenario. To control solar radiation is one key factor in low-energy thermal comfort. Computational-controlled sensor-based kinetic surfaces are one of the possible answers to control solar energy in an effective way, within the scope of contradictory objectives throughout the year.FC

Detection and prediction of urban archetypes at the pedestrian scale: computational toolsets, morphological metrics, and machine learning methods

Granular, dense, and mixed-use urban morphologies are hallmarks of walkable and vibrant streets. However, urban systems are notoriously complex and planned urban development, which grapples with varied interdependent and oft conflicting criteria, may — despite best intentions — yield aberrant morphologies fundamentally at odds with the needs of pedestrians and the resiliency of neighbourhoods. This work addresses the measurement, detection, and prediction of pedestrian-friendly urban archetypes by developing techniques for high-resolution urban analytics at the pedestrian scale. A spatial-analytic computational toolset, the cityseer-api Python package, is created to assess localised centrality, land-use, and statistical metrics using contextually sensitive workflows applied directly over the street network. cityseer-api subsequently facilitates a review of mixed-use and street network centrality methods to improve their utility concerning granular urban analysis. Unsupervised machine learning methods are applied to recover ‘signatures’ — urban archetypes — using Principal Component Analysis, Variational Autoencoders, and clustering methods from a high-resolution multi-variable and multi-scalar dataset consisting of centralities, land-uses, and population densities for Greater London. Supervised deep-learning methods applied to a similar dataset developed for 931 towns and cities in Great Britain demonstrate how, with the aid of domain knowledge, machine-learning classifiers can learn to discriminate between ‘artificial’ and ‘historical’ urban archetypes. These methods use complex systems thinking as a departure point and illustrate how high-resolution spatial-analytic quantitative methods can be combined with machine learning to extrapolate benchmarks in keeping with more qualitatively framed urban morphological conceptions. Such tools may aid urban design professionals in better anticipating the outcomes of varied design scenarios as part of iterative and scalable workflows. These techniques may likewise provide robust and demonstrable feedback as part of planning review and approvals processes

Interventions Towards Sustainable Watershed Management as Demonstrated by Hydrologic Simulation

Increasing population, changing climate, and on-going legacies of environmental mismanagement motivate our need for deeper understanding of the process and limits of adaptation towards sustainable management of water resources. Movements towards open-science and transdisciplinary research have enabled deeper assessments of the co-evolution of human society and changing landscapes. Policies and decisions enabling environmental restoration or sustainable resource use have been actively pursued for decades. The social barriers that prevent adaptations to succeed are deep and entrenched, but equally important are the physical barriers. Successful adaptations in water resource management need to explicitly consider the joint interactions of intervention magnitude, or intensity, over the feasible extent of its operation. While a seemingly simple concept, many solutions to water resource management would be impossible to achieve without adequate consideration of these constraints.In these three studies specific management practices were evaluated in the context of whole watershed responses and found to characterize this common constraint despite the diversity of applications. The three studies impose alternative management practices within a model of watershed-scale hydrologic processes, and the success of each practice was ultimately determined by the geographic constraints over which it could act, not by any deficiency in the policy’s capacity to affect a sufficient intensity of change. In Chapter 1, current rates of road salt loading and potential levels of aquatic habitat impairment are estimated for a New England watershed. The potential for reducing impairment through a combination of reduced salt application and buildout are investigated. Chapter 2 examines issues of aquifer sustainability in the Pacific Northwest and evaluates tradeoffs in modernizing irrigation technology. As irrigation efficiency increased less water recharged the aquifer, which exacerbated aquifer drawdown. Drawdown was offset by enhanced aquifer recharge directly from the river. The study analyzes the constraints under which aquifer drawdown can be eliminated while minimizing any reduction in streamflow. Chapter 3 evaluates the efficacy of two programs that incentivize the restoration of wetlands within the Mississippi River basin to reduce nitrogen export as nitrate export to the Gulf of Mexico. A more thorough consideration of geographic and engineering constraints on restoration illustrates how complementary management practices would be necessary to meet nutrient reduction goals. Finally, Chapter 4 analyzes the three studies and develops the concepts of intensity and extensity in successful practices in watershed management. Chapter 4 also lays out the common methodology of model experimentation in silico used throughout these studies, and defends the epistemological framework chosen

3D-in-2D Displays for ATC.

This paper reports on the efforts and accomplishments of the 3D-in-2D Displays for ATC project at the end of Year 1. We describe the invention of 10 novel 3D/2D visualisations that were mostly implemented in the Augmented Reality ARToolkit. These prototype implementations of visualisation and interaction elements can be viewed on the accompanying video. We have identified six candidate design concepts which we will further research and develop. These designs correspond with the early feasibility studies stage of maturity as defined by the NASA Technology Readiness Level framework. We developed the Combination Display Framework from a review of the literature, and used it for analysing display designs in terms of display technique used and how they are combined. The insights we gained from this framework then guided our inventions and the human-centered innovation process we use to iteratively invent. Our designs are based on an understanding of user work practices. We also developed a simple ATC simulator that we used for rapid experimentation and evaluation of design ideas. We expect that if this project continues, the effort in Year 2 and 3 will be focus on maturing the concepts and employment in a operational laboratory settings

Assessment of thermal and visual micro-climate of a traditional commercial street in a hot arid climate

PhD ThesisIn the hot arid contexts, the impact of urban climate is often associated with negative effects on outdoor thermal comfort and an increase in the urban heat island (UHI) effect. The primary aim of this research is to investigate the outdoor thermal performance of traditional commercial urban streets located in the hot arid context of Cairo in Egypt. A number of methods were used including field measurements and social surveys. Consequently, urban air flows, temperature and daylight simulations to assess existing and possible improvement scenarios to extend pedestrian thermal and visual comfort were tested. The field measurements were conducted in order to first assess the UHI intensity in the urban street, and to investigate the effectiveness of the traditional design solutions in ensuring comfortable outdoor conditions based on human-biometeorological assessment methods. Validation of results was carried out by comparing measured and simulated results of thermal conditions in the commercial spine ENVI-met is a three dimensional microclimatic model based on computational fluid dynamics (CFD) models and is designed to simulate surface-air interactions in urban environments. It was used to calculate the mean radiant temperature and obtaining the microclimatic maps with problematic areas concerning the pedestrian's thermal comfort for the existing urban configurations. Outdoor thermal comfort was assessed based on a thermal sensation survey and the physiological equivalent temperature (PET), with a comfort range of (24oC - 32oC). To improve outdoor thermal conditions at pedestrian level seven different shading scenarios addressing the form and the opening of shading devices were simulated using CFD Fluent, based on two dependant variables including air temperature distribution and wind velocity. The daylight analysis software (DIVA) was used to evaluate the solar access for the tested cases. The findings show that typology and the opening locations are one of the paramount factors in providing a temperature reduction in the urban scale. As the air temperature was reduced by (2.3oC) for the best case compared to the base leading to a lower PET for the best case recording 32.9oC against 35oC for the base case