Automatic Structure Generation using Genetic Programming and Fractal Geometry

Three dimensional model design is a well-known and studied field, with numerous real-world applications. However, the manual construction of these models can often be time-consuming to the average user, despite the advantages o ffered through computational advances. This thesis presents an approach to the design of 3D structures using evolutionary computation and L-systems, which involves the automated production of such designs using a strict set of fitness functions. These functions focus on the geometric properties of the models produced, as well as their quantifiable aesthetic value - a topic which has not been widely investigated with respect to 3D models. New extensions to existing aesthetic measures are discussed and implemented in the presented system in order to produce designs which are visually pleasing. The system itself facilitates the construction of models requiring minimal user initialization and no user-based feedback throughout the evolutionary cycle. The genetic programming evolved models are shown to satisfy multiple criteria, conveying a relationship between their assigned aesthetic value and their perceived aesthetic value. Exploration into the applicability and e ffectiveness of a multi-objective approach to the problem is also presented, with a focus on both performance and visual results. Although subjective, these results o er insight into future applications and study in the fi eld of computational aesthetics and automated structure design.

Automatic evolution of conceptual building architectures

This thesis describes research in which genetic programming is used to automatically evolve shape grammars that construct three dimensional models of possible external building architectures. A completely automated fitness function is used, which evaluates the three dimensional building models according to different geometric properties such as surface normals, height, building footprint, and more. In order to evaluate the buildings on the different criteria, a multi-objective fitness function is used. The results obtained from the automated system were successful in satisfying the multiple objective criteria as well as creating interesting and unique designs that a human-aided system might not discover. In this study of evolutionary design, the architectures created are not meant to be fully functional and structurally sound blueprints for constructing a building, but are meant to be inspirational ideas for possible architectural designs. The evolved models are applicable for today's architectural industries as well as in the video game and movie industries. Many new avenues for future work have also been discovered and highlighted.

Evolutionary Origin and Maintenance of Sociality in the Small Carpenter Bees

Many arthropods exhibit behaviours precursory to social life, including adult longevity, parental care, nest loyalty and mutual tolerance, yet there are few examples of social behaviour in this phylum. The small carpenter bees, genus Ceratina, provide important insights into the early stages of sociality. I described the biology and social behaviour of five facultatively social species which exhibit all of the preadaptations for successful group living, yet present ecological and behavioural characteristics that seemingly disfavour frequent colony formation. These species are socially polymorphic with both / solitary and social nests collected in sympatry. Social colonies consist of two adult females, one contributing both foraging and reproductive effort and the second which remains at the nest as a passive guard. Cooperative nesting provides no overt reproductive benefits over solitary nesting, although brood survival tends to be greater in social colonies. Three main theories explain cooperation among conspecifics: mutual benefit, kin selection and manipulation. Lifetime reproductive success calculations revealed that mutual benefit does not explain social behaviour in this group as social colonies have lower per capita life time reproductive success than solitary nests. Genetic pedigrees constructed from allozyme data indicate that kin selection might contribute to the maintenance of social nesting -, as social colonies consist of full sisters and thus some indirect fitness benefits are inherently bestowed on subordinate females as a result of remaining to help their dominant sister. These data suggest that the origin of sociality in ceratinines has principal costs and the great ecological success of highly eusociallineages occurred well after social origins. Ecological constraints such as resource limitation, unfavourable weather conditions and parasite pressure have long been considered some of the most important selective pressures for the evolution of sociality. I assessed the fitness consequences of these three ecological factors for reproductive success of solitary and social colonies and found that nest sites were not limiting, and the frequency of social nesting was consistent across brood rearing seasons. Local weather varied between seasons but was not correlated with reproductive success. Severe parasitism resulted in low reproductive success and total nest failure in solitary nests. Social colonies had higher reproductive success and were never extirpated by parasites. I suggest that social nesting represents a form of bet-hedging. The high frequency of solitary nests suggests that this is the optimal strategy when parasite pressure is low. However, social colonies have a selective advantage over solitary nesting females during periods of extreme parasite pressure. Finally, the small carpenter bees are recorded from all continents except Antarctica. I constructed the first molecular phylogeny of ceratinine bees based on four gene regions of selected species covering representatives from all continents and ecological regions. Maximum parsimony and Bayesian Inference tree topology and fossil dating support an African origin followed by an Old World invasion and New World radiation. All known Old World ceratinines form social colonies while New World species are largely solitary; thus geography and phylogenetic inertia are likely predictors of social evolution in this genus. This integrative approach not only describes the behaviour of several previously unknown or little-known Ceratina species, bu~ highlights the fact that this is an important, though previously unrecognized, model for studying evolutionary transitions from solitary to social behaviour.

Influence of dietary nutrients on life history-related traits of black flies and mosquitoes

The sugar-feeding ecology of dipteran vectors has recently been targeted because it presents opportunities to inoculate common food sources for these dipterans with entomopathogenic bacteria as a means of controlling the population of host-seeking adult dipteran vectors. Whereas this approach to vector control holds some promise, differences in the nutrient composition and concentration in sugary food sources can influence the food selection pattern of dipteran vectors and potentially confound the outcomes of field trials on the efficacy of entomopathogenic bacteria as vector control agents. Further, nutrient components of bacteria-inoculated artificial diets may present unintended effects of extending the survivorship or fecundity of the target population and potentially render the whole approach counterproductive. The present study investigated the diet-specific factors that influence the foraging decisions of female Simulium venustum/verecundum (Diptera: Simuliidae) and female Anopheles stephensi (Diptera: Culicidae) on artificial nectar and honeydew. Paired choice experiments showed that the black flies forage more frequently from high calorie diets, which contained melezitose, or those diets that contained amino acids, compared to low calorie melezitose-free diets or amino acid-free diets. The mosquitoes however displayed a more random diet selection pattern. The effects of sugary diets on certain life-history traits considered to be important to the ecological fitness of the black flies and mosquitoes were also investigated. Sugary diets had no significant effect on the survivorship and fecundity of the black flies, but they influenced the resistance of Leucocytozoon-infected flies to the parasite. Amino acid-containing diets appeared to extend the survival of mosquitoes, and also allowed them to take more vertebrate blood when they blood fed.

The Implications of Forager Behaviour for Social Organisation in a Socially Polymorphic Carpenter Bee (Xylocopa virginica)

In social Hymenoptera, the division of labour is a major step in the evolution of sociality. Bees, which express many different kinds of sociality, can be classified according to how individuals share or do not share foraging and reproductive activities (Michener, 1974). The large carpenter bee, Xylocopa virginica, lives in populations with both solitary and social nests. In social nests, reproduction is controlled by the dominant female, who does all of her own foraging and egg-laying, while the subordinates guard the nest only. This study examined foraging behaviour as a way to classify the social hierarchy. Individual females were marked, measured and intensely observed for the foraging season. It was found that a large number of subordinates forage and likely obtain more reproductive fitness than previously thought. The dominance hierarchy is very likely a social queue, in which bees take turns foraging and egg-laying.

Genetic Programming for Non-Photorealistic Rendering

This thesis focuses on developing an evolutionary art system using genetic programming. The main goal is to produce new forms of evolutionary art that filter existing images into new non-photorealistic (NPR) styles, by obtaining images that look like traditional media such as watercolor or pencil, as well as brand new effects. The approach permits GP to generate creative forms of NPR results. The GP language is extended with different techniques and methods inspired from NPR research such as colour mixing expressions, image processing filters and painting algorithm. Colour mixing is a major new contribution, as it enables many familiar and innovative NPR effects to arise. Another major innovation is that many GP functions process the canvas (rendered image), while is dynamically changing. Automatic fitness scoring uses aesthetic evaluation models and statistical analysis, and multi-objective fitness evaluation is used. Results showed a variety of NPR effects, as well as new, creative possibilities.

Is Pride a Vice or a Virtue? Associations to Well-Being and Physical Activity

The first objective of the present study was to determine patterns of association between authentic and hubristic fitness-related pride to outcomes of well-being and leisure-time physical activity (LTPA). A second objective was to examine motivation as a potential mediator of these relationships. Participants (N = 119) were young adults who completed self-report questionnaires at two time points separated by 4-weeks. Authentic and hubristic pride were associated with well-being and LTPA at Time 1 and Time 2. Changes in pride were associated with changes in well-being but not LTPA. Results of the mediation analyses highlight the role of more autonomous motives, specifically intrinsic motivation, as important mediators between pride and well-being. Motivation did not mediate the relationship between pride and LTPA. Overall, both authentic and hubristic pride seem to be important in the promotion of well-being More research is needed to elucidate the relationship between pride and LTPA.

Challenging Weight Loss: The Effectiveness of a 12 Week Weight Loss Challenge on Weight Loss, Physical Activity and Motivation

The objective of this study was to examine the effectiveness of a 12 week weight loss intervention in a commercial fitness centre on body mass index (BMI), moderate to vigorous physical activity (MVPA) and behavioural regulations consistent with Organismic Integration Theory (OIT, Deci & Ryan, 2002). The intervention group received weekly coaching sessions and bi-weekly seminars designed to increase MVPA and improve dietary intake. The results of the mixed model analyses of variance showed a significant within-subjects main effect for BMI (F = 3.57, p = .04). Changes in MVPA were not observed over time or between conditions. Changes in behavioural regulations congruent with OIT (Deci & Ryan, 2002) favoured the intervention condition. Study results indicate that 12 week weight loss challenges in commercial fitness centres may be effective to support the internalization process of exercise behavioural regulations but ineffective at producing sustainable weight loss or behavioural changes.

The Influence of Male Diet on Life History Traits of Female Mosquitoes

In the field, mosquitoes characteristically feed on sugars soon after emergence and intermittently during their adult lives. Sugar meals are commonly derived from plant nectar and homopteran honeydew, and without them, adults can only survive for a few days on larval reserves. In addition to sugar, females of most species rely on blood for the initiation and maintenance of egg development; thus their reproductive success depends to some extent on the availability of blood hosts. Males, on the other hand, feed exclusively on sugars. Consequently, their sexual maturation and reproductive success is largely dependent upon access to sugar sources. Plant nectar and homopteran honeydew are the two main sugar sources utilized by mosquitoes in the wild. Previous laboratory studies had shown that differences between nectar sources can affect the survivorship and biting frequency of disease vectoring mosquitoes. However, little is known on how sugar composition influence the reproductive processes in male mosquitoes. Male mosquitoes transfer accessory gland proteins and other hormones to their mates along with sperm during mating. In the female, these seminal fluid constituents exert their influence on reproductive genes that control ovulation and vitellogenesis. The present study tests the hypothesis that the mates of males consuming different sugar meals will exhibit varying levels of induction of vitellogenin (a gene which regulates the expression of egg yolk precursor proteins). Real-time quantitative RT-PCR was used to investigate how each sugar meal indirectly influences vitellogenin mRNA abundance in female Anopheles stephensi following mating. Results indicate that mates of nectar-fed males exhibit 2-fold greater change in vitellogenin expression than the mates of honeydew-fed males. However, this response did not occur in non-blood fed controls. These findings suggest that the stimulatory effect of mating on vitellogenesis in blood meal-reliant (i.e. anautogenous) mosquitoes may only be synergistic in nature. The present study also sought to compare the potential fitness costs of mating incurred by females that do not necessarily require a blood meal to initiate a reproductive cycle (i.e., exhibit autogeny). Females of the facultatively autogenous mosquito, Culex molestus were allowed to mate with males sustained on either nectar or honedyew. Mean lifetime fecundity and survivorship of females under the two different mating regimes were then recorded. Additionally, one-dimensional gel electrophoresis was used to verify the transfer of male accessory gland proteins to the sperm storage organs of females during mating.While there was no significant difference in survival between the test treatments, the mates of nectar-fed males produced 11% more eggs on average than mates of honeydew-fed males. However, additional data are needed to justify the extrapolation of these findings to natural settings. These findings prompt further investigation as the differences caused by diet variation in males may be reflected across other life history traits such as mating frequency and insemination capacity.

Autonomic and Electrophysiological Correlates of Cognitive Control in Aging

This thesis tested a model of neurovisceral integration (Thayer & Lane, 2001) wherein parasympathetic autonomic regulation is considered to play a central role in cognitive control. We asked whether respiratory sinus arrhythmia (RSA), a parasympathetic index, and cardiac workload (rate pressure product, RPP) would influence cognition and whether this would change with age. Cognitive control was measured behaviourally and electrophysiologically through the error-related negativity (ERN) and error positivity (Pe). The ERN and Pe are thought to be generated by the anterior cingulate cortex (ACC), a region involved in regulating cognitive and autonomic control and susceptible to age-related change. In Study 1, older and younger adults completed a working memory Go/NoGo task. Although RSA did not relate to performance, higher pre-task RPP was associated with poorer NoGo performance among older adults. Relations between ERN/Pe and accuracy were indirect and more evident in younger adults. Thus, Study 1 supported the link between cognition and autonomic activity, specifically, cardiac workload in older adults. In Study 2, we included younger adults and manipulated a Stroop task to clarify conditions under which associations between RSA and performance will likely emerge. We varied task parameters to allow for proactive versus reactive strategies, and motivation was increased via financial incentive. Pre-task RSA predicted accuracy when response contingencies required maintenance of a specific item in memory. Thus, RSA was most relevant when performance required proactive control, a metabolically costly strategy that would presumably be more reliant on autonomic flexibility. In Study 3, we included older adults and examined RSA and proactive control in an additive factors framework. We maintained the incentive and measured fitness. Higher pre-task RSA among older adults was associated with greater accuracy when proactive control was needed most. Conversely, performance of young women was consistently associated with fitness. Relations between ERN/Pe and accuracy were modest; however, isolating ACC activity via independent component analysis allowed for more associations with accuracy to emerge in younger adults. Thus, performance in both groups appeared to be differentially dependent on RSA and ACC activation. Altogether, these data are consistent with a neurovisceral integration model in the context of cognitive control.

Network Similarity Measures and Automatic Construction of Graph Models using Genetic Programming

A complex network is an abstract representation of an intricate system of interrelated elements where the patterns of connection hold significant meaning. One particular complex network is a social network whereby the vertices represent people and edges denote their daily interactions. Understanding social network dynamics can be vital to the mitigation of disease spread as these networks model the interactions, and thus avenues of spread, between individuals. To better understand complex networks, algorithms which generate graphs exhibiting observed properties of real-world networks, known as graph models, are often constructed. While various efforts to aid with the construction of graph models have been proposed using statistical and probabilistic methods, genetic programming (GP) has only recently been considered. However, determining that a graph model of a complex network accurately describes the target network(s) is not a trivial task as the graph models are often stochastic in nature and the notion of similarity is dependent upon the expected behavior of the network. This thesis examines a number of well-known network properties to determine which measures best allowed networks generated by different graph models, and thus the models themselves, to be distinguished. A proposed meta-analysis procedure was used to demonstrate how these network measures interact when used together as classifiers to determine network, and thus model, (dis)similarity. The analytical results form the basis of the fitness evaluation for a GP system used to automatically construct graph models for complex networks. The GP-based automatic inference system was used to reproduce existing, well-known graph models as well as a real-world network. Results indicated that the automatically inferred models exemplified functional similarity when compared to their respective target networks. This approach also showed promise when used to infer a model for a mammalian brain network.

Conceptions of Quality and Approaches to Quality Assurance in Ontario’s Universities

Many international, political, and economic influences led to increased demands for development of new quality assurance systems for universities. Like many policies and processes that aim to assure quality, Ontario’s Quality Assurance Framework (QAF) did not define quality. This study sought to explore conceptions of quality and approaches to quality assurance used within Ontario’s universities. A document analysis of the QAF’s rationale and structure suggested that quality was conceived primarily as fitness for purpose, while suggested indicators represented an exceptional conception of quality. Ontario universities perpetuated such confusion by adopting the framework without customizing it to their institutional conceptions of quality. Drawing upon phenomenographic traditions, a qualitative investigation was conducted to better understand various conceptions of quality held by university administrators and to appreciate ways in which they implemented the QAF. Three main approaches to quality assurance were identified: (a) Defending Quality, characterized by conceptions of quality as exceptional, which focuses on administrative accountability and uses a hands-off strategy to defend traditional notions of quality inputs and resources; (b) Demonstrating Quality, characterized by conceptions of quality as fitness for purpose and value for money, which focuses on accountability to students and uses centralized engaged strategies to demonstrate how programs meet current priorities and intended outcomes; and (c) Enhancing Quality, characterized by conceptions of quality as transformation, which focuses on reflection and learning experience and uses engaged strategies to find new ways of improving learning and teaching. The development of a campus culture that values the institution’s function in student learning and quality teaching would benefit from Enhancing Quality approaches to quality assurance. This would require holistic consideration of the beliefs held by members of the institution, a clear articulation of the institution’s conceptions of quality, and a critical analysis of how these conceptions align with institutional practices and policies.

Inverse Illumination Design with Genetic Programming

Interior illumination is a complex problem involving numerous interacting factors. This research applies genetic programming towards problems in illumination design. The Radiance system is used for performing accurate illumination simulations. Radiance accounts for a number of important environmental factors, which we exploit during fitness evaluation. Illumination requirements include local illumination intensity from natural and artificial sources, colour, and uniformity. Evolved solutions incorporate design elements such as artificial lights, room materials, windows, and glass properties. A number of case studies are examined, including many-objective problems involving up to 7 illumination requirements, the design of a decorative wall of lights, and the creation of a stained-glass window for a large public space. Our results show the technical and creative possibilities of applying genetic programming to illumination design.

The Clinical Translation Gap in Child Health Exercise Research: A Call for Disruptive Innovation

In children, levels of play, physical activity, and fitness are key indicators of health and disease and closely tied to optimal growth and development. Cardiopulmonary exercise testing (CPET) provides clinicians with biomarkers of disease and effectiveness of therapy, and researchers with novel insights into fundamental biological mechanisms reflecting an integrated physiological response that is hidden when the child is at rest. Yet the growth of clinical trials utilizing CPET in pediatrics remains stunted despite the current emphasis on preventative medicine and the growing recognition that therapies used in children should be clinically tested in children. There exists a translational gap between basic discovery and clinical application in this essential component of child health. To address this gap, the NIH provided funding through the Clinical and Translational Science Award (CTSA) program to convene a panel of experts. This report summarizes our major findings and outlines next steps necessary to enhance child health exercise medicine translational research. We present specific plans to bolster data interoperability, improve child health CPET reference values, stimulate formal training in exercise medicine for child health care professionals, and outline innovative approaches through which exercise medicine can become more accessible and advance therapeutics across the child health spectrum.

Feature Selection and Classification Using Age Layered Population Structure Genetic Programming

The curse of dimensionality is a major problem in the fields of machine learning, data mining and knowledge discovery. Exhaustive search for the most optimal subset of relevant features from a high dimensional dataset is NP hard. Sub–optimal population based stochastic algorithms such as GP and GA are good choices for searching through large search spaces, and are usually more feasible than exhaustive and deterministic search algorithms. On the other hand, population based stochastic algorithms often suffer from premature convergence on mediocre sub–optimal solutions. The Age Layered Population Structure (ALPS) is a novel metaheuristic for overcoming the problem of premature convergence in evolutionary algorithms, and for improving search in the fitness landscape. The ALPS paradigm uses an age–measure to control breeding and competition between individuals in the population. This thesis uses a modification of the ALPS GP strategy called Feature Selection ALPS (FSALPS) for feature subset selection and classification of varied supervised learning tasks. FSALPS uses a novel frequency count system to rank features in the GP population based on evolved feature frequencies. The ranked features are translated into probabilities, which are used to control evolutionary processes such as terminal–symbol selection for the construction of GP trees/sub-trees. The FSALPS metaheuristic continuously refines the feature subset selection process whiles simultaneously evolving efficient classifiers through a non–converging evolutionary process that favors selection of features with high discrimination of class labels. We investigated and compared the performance of canonical GP, ALPS and FSALPS on high–dimensional benchmark classification datasets, including a hyperspectral image. Using Tukey’s HSD ANOVA test at a 95% confidence interval, ALPS and FSALPS dominated canonical GP in evolving smaller but efficient trees with less bloat expressions. FSALPS significantly outperformed canonical GP and ALPS and some reported feature selection strategies in related literature on dimensionality reduction.