88 research outputs found

    The Evolution of Complexity in Autonomous Robots

    Get PDF
    Evolutionary robotics–the use of evolutionary algorithms to automate the production of autonomous robots–has been an active area of research for two decades. However, previous work in this domain has been limited by the simplicity of the evolved robots and the task environments within which they are able to succeed. This dissertation aims to address these challenges by developing techniques for evolving more complex robots. Particular focus is given to methods which evolve not only the control policies of manually-designed robots, but instead evolve both the control policy and physical form of the robot. These techniques are presented along with their application to investigating previously unexplored relationships between the complexity of evolving robots and the task environments within which they evolve

    Environmental Influence on the Evolution of Morphological Complexity in Machines

    Get PDF
    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

    Evolving Monolithic Robot Controllers through Incremental Shaping

    Get PDF
    Evolutionary robotics has been shown to be an effective technique for generating robot behaviors that are difficult to derive analytically from the robot’s mechanics and task environment. Moreover, augmenting evolutionary algorithms with environmental scaffolding via an incremental shaping method makes it possible to evolve controllers for complex tasks that would otherwise be infeasible. In this paper we present a summary of two recent publications in the evolutionary robotics literature demonstrating how these methods can be used to evolve robot controllers for non-trivial tasks, what the obstacles are in evolving controllers in this way, and present a novel research question that can be investigated under this framework

    Gaining Insight into Quality Diversity

    Get PDF
    Recently there has been a growing movement of researchers that believes innovation and novelty creation, rather than pure optimization, are the true strengths of evolutionary algorithms relative to other forms of machine learning. This idea also provides one possible explanation for why evolutionary processes may exist in nervous systems on top of other forms of learning. One particularly exciting corollary of this, is that evolutionary algorithms may be used to produce what Pugh et al have dubbed Quality Diversity (QD): as many as possible different solutions (according to some characterization), which are all as fit as possible. While the notion of QD implies choosing the dimensions on which to measure diversity and performance, we propose that it may be possible (and desirable) to free the evolutionary process from requiring defining these dimensions. Toward that aim, we seek to understand more about QD in general by investigating how algorithms informed by different measures of diversity (or none at all) create QD, when that QD is measured in a diversity of ways

    Cervical spinal cord dimensions and clinical outcomes in adults with Klippel-Feil syndrome: A comparison with matched controls.

    Get PDF
    Study Design Retrospective case–control study. Objectives To confirm the fact that spinal cord dimensions are smaller in adults with Klippel-Feil syndrome (KFS) than in pediatric patients with KFS and to compare the clinical characteristics and outcomes of neurologic complications in patients with KFS with matched controls. Methods We performed an independent 1:2 case–control retrospective radiographic and chart review of a consecutive series of adults with KFS who underwent surgical intervention. The control group consisted of consecutive non-KFS surgical patients. Patients were matched in 1:2 case–control manner. Their charts were reviewed and the clinical characteristics were compared. Axial T2-weighted magnetic resonance imaging (MRI) was used to measure the anteroposterior and mediolateral axial spinal cord and spinal canal at the operative levels and measurements were compared. Results A total of 22 patients with KFS and 44 controls were identified. The KFS group had a tendency of more myeloradiculopathy, and the control group had a tendency toward more radiculopathy. Both tendencies, however, were not significantly different. MRIs of 10 patients from the KFS group and 22 controls were available. There was no difference in the area of both spinal cord and canal at the operative levels. Conclusion Contrary to the finding in previous reports on pediatric patients, there were no differences between KFS and well-matched control groups in terms of age of onset, presentation, revision rate, complication rate, surgical outcome, and cross-sectional spinal cord and canal dimensions at the operative level

    WebAL Comes of Age: A review of the first 21 years of Artificial Life on the Web

    Get PDF
    We present a survey of the first 21 years of web-based artificial life (WebAL) research and applications, broadly construed to include the many different ways in which artificial life and web technologies might intersect. Our survey covers the period from 1994—when the first WebAL work appeared—up to the present day, together with a brief discussion of relevant precursors. We examine recent projects, from 2010–2015, in greater detail in order to highlight the current state of the art. We follow the survey with a discussion of common themes and methodologies that can be observed in recent work and identify a number of likely directions for future work in this exciting area

    Exposure and confidence across critical airway procedures in pediatric emergency medicine: An international survey study

    Get PDF
    Background: Airway management procedures are critical for emergency medicine (EM) physicians, but rarely performed skills in pediatric patients. Worldwide experience with respect to frequency and confidence in performing airway management skills has not been previously described. Objectives: Our aims were 1) to determine the frequency with which emergency medicine physicians perform airway procedures including: bag-mask ventilation (BMV), endotracheal intubation (ETI), laryngeal mask airway (LMA) insertion, tracheostomy tube change (TTC), and surgical airways, and 2) to investigate predictors of procedural confidence regarding advanced airway management in children. Methods: A web-based survey of senior emergency physicians was distributed through the six research networks associated with Pediatric Emergency Research Network (PERN). Senior physician was defined as anyone working without direct supervision at any point in a 24-h cycle. Physicians were queried regarding their most recent clinical experience performing or supervising airway procedures, as well as with hands on practice time or procedural teaching. Reponses were dichotomized to within the last year, or ≥ 1 year. Confidence was assessed using a Likert scale for each procedure, with results for ETI and LMA stratified by age. Response levels were dichotomized to “not confident” or “confident.” Multivariate regression models were used to assess relevant associations. Results: 1602 of 2446 (65%) eligible clinicians at 96 PERN sites responded. In the previous year, 1297 (85%) physicians reported having performed bag-mask ventilation, 900 (59%) had performed intubation, 248 (17%) had placed a laryngeal mask airway, 348 (23%) had changed a tracheostomy tube, and 18 (1%) had performed a surgical airway. Of respondents, 13% of physicians reported the opportunity to supervise but not provide ETI, 5% for LMA and 5% for BMV. The percentage of physicians reporting “confidence” in performing each procedure was: BMV (95%) TTC (43%), and surgical airway (16%). Clinician confidence in ETT and LMA varied by patient age. Supervision of an airway procedure was the strongest predictor of procedural confidence across airway procedures. Conclusion: BMV and ETI were the most commonly performed pediatric airway procedures by emergency medicine physicians, and surgical airways are very infrequent. Supervising airway procedures may serve to maintain procedural confidence for physicians despite infrequent opportunities as the primary proceduralist

    Fourteen Recommendations to Create a More Inclusive Environment for LGBTQ+ Individuals in Academic Biology

    Full text link
    Individuals who identify as lesbian, gay, bisexual, transgender, queer, and otherwise non-straight and/or non-cisgender (LGBTQ+) have often not felt welcome or represented in the biology community. Additionally, biology can present unique challenges for LGBTQ+ students because of the relationship between certain biology topics and their LGBTQ+ identities. Currently, there is no centralized set of guidelines to make biology learning environments more inclusive for LGBTQ+ individuals. Rooted in prior literature and the collective expertise of the authors who identify as members and allies of the LGBTQ+ community, we present a set of actionable recommendations to help biologists, biology educators, and biology education researchers be more inclusive of individuals with LGBTQ+ identities. These recommendations are intended to increase awareness of LGBTQ+ identities and spark conversations about transforming biology learning spaces and the broader academic biology community to become more inclusive of LGBTQ+ individuals
    corecore