Towards the Evolution of Novel Vertical-Axis Wind Turbines

Renewable and sustainable energy is one of the most important challenges currently facing mankind. Wind has made an increasing contribution to the world's energy supply mix, but still remains a long way from reaching its full potential. In this paper, we investigate the use of artificial evolution to design vertical-axis wind turbine prototypes that are physically instantiated and evaluated under approximated wind tunnel conditions. An artificial neural network is used as a surrogate model to assist learning and found to reduce the number of fabrications required to reach a higher aerodynamic efficiency, resulting in an important cost reduction. Unlike in other approaches, such as computational fluid dynamics simulations, no mathematical formulations are used and no model assumptions are made.Comment: 14 pages, 11 figure

Data-efficient Neuroevolution with Kernel-Based Surrogate Models

Surrogate-assistance approaches have long been used in computationally expensive domains to improve the data-efficiency of optimization algorithms. Neuroevolution, however, has so far resisted the application of these techniques because it requires the surrogate model to make fitness predictions based on variable topologies, instead of a vector of parameters. Our main insight is that we can sidestep this problem by using kernel-based surrogate models, which require only the definition of a distance measure between individuals. Our second insight is that the well-established Neuroevolution of Augmenting Topologies (NEAT) algorithm provides a computationally efficient distance measure between dissimilar networks in the form of "compatibility distance", initially designed to maintain topological diversity. Combining these two ideas, we introduce a surrogate-assisted neuroevolution algorithm that combines NEAT and a surrogate model built using a compatibility distance kernel. We demonstrate the data-efficiency of this new algorithm on the low dimensional cart-pole swing-up problem, as well as the higher dimensional half-cheetah running task. In both tasks the surrogate-assisted variant achieves the same or better results with several times fewer function evaluations as the original NEAT.Comment: In GECCO 201

Unshackling evolution: evolving soft robots with multiple materials and a powerful generative encoding

In 1994 Karl Sims showed that computational evolution can produce interesting morphologies that resemble natural organisms. Despite nearly two decades of work since, evolved morphologies are not obviously more complex or natural, and the field seems to have hit a complexity ceiling. One hypothesis for the lack of increased complexity is that most work, including Sims’, evolves morphologies composed of rigid elements, such as solid cubes and cylinders, limiting the design space. A second hypothesis is that the encodings of previous work have been overly regular, not allowing complex regularities with variation. Here we test both hypotheses by evolving soft robots with multiple materials and a powerful generative encoding called a compositional pattern-producing network (CPPN). Robots are selected for locomotion speed. We find that CPPNs evolve faster robots than a direct encoding and that the CPPN morphologies appear more natural. We also find that locomotion performance increases as more materials are added, that diversity of form and behavior can be increased with di↵erent cost functions without stifling performance, and that organisms can be evolved at di↵erent levels of resolution. These findings suggest the ability of generative soft-voxel systems to scale towards evolving a large diversity of complex, natural, multi-material creatures. Our results suggest that future work that combines the evolution of CPPNencoded soft, multi-material robots with modern diversityencouraging techniques could finally enable the creation of creatures far more complex and interesting than those produced by Sims nearly twenty years ago

Morphogenetic Vase Forms

This paper describes Vase Forms: a series of art works created using morphogenetic processes. A key motivation for these works was exploration of ways of working creatively with complex generative processes, such as morphogenetic systems, where the desire is to be able to influence the process in creative directions whilst achieving desired properties, such as fabricability using 3D printing, in a manner that retains rich emergence. The paper describes methods used in the creation of these works, including directly affecting morphogenetic processes using constraints and differential growth rates, combined with evolutionary search and machine learning algorithms to explore the space of possibilities afforded by the system. As well as describing the creation of Vase Forms, which have been successfully used to create sculptures, the paper looks at the closely related Mutant Vase Forms: an additional series of artworks created by accident when the system exploited bugs in the rules for the growth system resulting in unexpected but aesthetically interesting structures. These Mutant Vase Forms are not fabricable as physical sculptures with the originally intended methods, but now exist as virtual sculptures in stereoscopic installations

Adapting models of visual aesthetics for personalized content creation

This paper introduces a search-based approach to personalized content generation with respect to visual aesthetics. The approach is based on a two-step adaptation procedure where (1) the evaluation function that characterizes the content is adjusted to match the visual aesthetics of users and (2) the content itself is optimized based on the personalized evaluation function. To test the efficacy of the approach we design fitness functions based on universal properties of visual perception, inspired by psychological and neurobiological research. Using these visual properties we generate aesthetically pleasing 2D game spaceships via neuroevolutionary constrained optimization and evaluate the impact of the designed visual properties on the generated spaceships. The offline generated spaceships are used as the initial population of an interactive evolution experiment in which players are asked to choose spaceships according to their visual taste: the impact of the various visual properties is adjusted based on player preferences and new content is generated online based on the updated computational model of visual aesthetics of the player. Results are presented which show the potential of the approach in generating content which is based on subjective criteria of visual aesthetics.Thanks to all the participants of the interactive evolution experiement. The research was supported, in part, by the FP7 ICT project SIREN (project no: 258453) and by the Danish Research Agency, Ministry of Science, Technology and Innovation project AGameComIn; project number: 274- 09-0083.peer-reviewe

Environmental Influence on the Evolution of Morphological Complexity in Machines

Whether, when, how, and why increased complexity evolves in biological populations is a longstanding open question. In this work we combine a recently developed method for evolving virtual organisms with an information-theoretic metric of morphological complexity in order to investigate how the complexity of morphologies, which are evolved for locomotion, varies across different environments. We first demonstrate that selection for locomotion results in the evolution of organisms with morphologies that increase in complexity over evolutionary time beyond what would be expected due to random chance. This provides evidence that the increase in complexity observed is a result of a driven rather than a passive trend. In subsequent experiments we demonstrate that morphologies having greater complexity evolve in complex environments, when compared to a simple environment when a cost of complexity is imposed. This suggests that in some niches, evolution may act to complexify the body plans of organisms while in other niches selection favors simpler body plans

Antspicbreeder: arte evolutiva produzida por formigas artificiais

Tese de mestrado em Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2013Os insetos sociais são conhecidos pelas suas extraordinárias capacidades auto-organizativas e cooperativas, que se traduzem em comportamentos coletivos complexos, mesmo quando a nível individual existe um acesso limitado a informação. As formigas da espécie Temnothorax albipennis constroem um dos ninhos mais simples encontrados entre os insetos sociais. Os seus ninhos têm propriedades específicas no que respeita à sua dinâmica, dado que se baseiam num template que adapta o tamanho do ninho de acordo com o número de indivíduos pertencentes à colónia. O template não é implementado fisicamente, mas é uma força que orienta a construção. No presente modelo, é concretizada uma representação de um sistema computacional evolucionário interativo, semelhante ao Picbreeder original, mas que contempla um nível de opacidades sobre as imagens originais. Estes pontos têm como principal intuito ocultar sua visibilidade das imagens e promover a emergência de designs compostos pelos trilhos de cores das formigas. Este parâmetro é fixo ao longo da evolução de cada geração. Cada espécie de formigas é definida por uma cor central e um intervalo de tolerância centrado nessa cor. O efeito de template para cada uma das espécies é dado pelas zonas de cores da imagem que coincidam com os respetivos intervalos de tolerância cor. Estes templates podem ser parcialmente visíveis logo desde o início da evolução, no momento em que as formigas partem para a sua atividade transformadora. Neste sistema as colónias de formigas têm capacidades comportamentais dinâmicas que lhes permite adaptar o seu trabalho de acordo com as alterações morfológicas de um template.Social insects are known for their extraordinary capabilities of self-organizing and cooperative behaviors, which are reflected through complex collective behaviors, even when individuals are limited in accessing local information. Ants of Temnothorax albipennis specie build one of the simplest nests found among social insects. The nests have specific properties regarding to its dynamic, since they are based on a template the size of the nest is adjusted in accordance with the number of individuals of the colony. The template is not implemented physically, but it is a driving force behind the construction. In this model, we achieved a representation of an interactive evolutionary system, similar to the original Picbreeder but which includes a level of opacities above the original images with the purpose to hide its visibility and promote the emergence of designs composed by the color rails made by the involved artificial ants. This parameter is fixed throughout the evolution of each generation. A center color and a range of tolerance define each species of ants. The areas of the image colors that match the respective color tolerance give the effect of template. These templates can be partially visible from the very beginning of evolution, when ants start their transforming activity. In this system, ant’s colonies have a dynamic behavioral capability that allows them to adapt their work according to the morphological changes of the template

A complex systems approach to education in Switzerland

The insights gained from the study of complex systems in biological, social, and engineered systems enables us not only to observe and understand, but also to actively design systems which will be capable of successfully coping with complex and dynamically changing situations. The methods and mindset required for this approach have been applied to educational systems with their diverse levels of scale and complexity. Based on the general case made by Yaneer Bar-Yam, this paper applies the complex systems approach to the educational system in Switzerland. It confirms that the complex systems approach is valid. Indeed, many recommendations made for the general case have already been implemented in the Swiss education system. To address existing problems and difficulties, further steps are recommended. This paper contributes to the further establishment complex systems approach by shedding light on an area which concerns us all, which is a frequent topic of discussion and dispute among politicians and the public, where billions of dollars have been spent without achieving the desired results, and where it is difficult to directly derive consequences from actions taken. The analysis of the education system's different levels, their complexity and scale will clarify how such a dynamic system should be approached, and how it can be guided towards the desired performance