6 research outputs found

    Safe Robot Planning and Control Using Uncertainty-Aware Deep Learning

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    In order for robots to autonomously operate in novel environments over extended periods of time, they must learn and adapt to changes in the dynamics of their motion and the environment. Neural networks have been shown to be a versatile and powerful tool for learning dynamics and semantic information. However, there is reluctance to deploy these methods on safety-critical or high-risk applications, since neural networks tend to be black-box function approximators. Therefore, there is a need for investigation into how these machine learning methods can be safely leveraged for learning-based controls, planning, and traversability. The aim of this thesis is to explore methods for both establishing safety guarantees as well as accurately quantifying risks when using deep neural networks for robot planning, especially in high-risk environments. First, we consider uncertainty-aware Bayesian Neural Networks for adaptive control, and introduce a method for guaranteeing safety under certain assumptions. Second, we investigate deep quantile regression learning methods for learning time-and-state varying uncertainties, which we use to perform trajectory optimization with Model Predictive Control. Third, we introduce a complete framework for risk-aware traversability and planning, which we use to enable safe exploration of extreme environments. Fourth, we again leverage deep quantile regression and establish a method for accurately learning the distribution of traversability risks in these environments, which can be used to create safety constraints for planning and control.Ph.D

    Collaborative Localization and Mapping for Autonomous Planetary Exploration : Distributed Stereo Vision-Based 6D SLAM in GNSS-Denied Environments

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    Mobile robots are a crucial element of present and future scientific missions to explore the surfaces of foreign celestial bodies such as Moon and Mars. The deployment of teams of robots allows to improve efficiency and robustness in such challenging environments. As long communication round-trip times to Earth render the teleoperation of robotic systems inefficient to impossible, on-board autonomy is a key to success. The robots operate in Global Navigation Satellite System (GNSS)-denied environments and thus have to rely on space-suitable on-board sensors such as stereo camera systems. They need to be able to localize themselves online, to model their surroundings, as well as to share information about the environment and their position therein. These capabilities constitute the basis for the local autonomy of each system as well as for any coordinated joint action within the team, such as collaborative autonomous exploration. In this thesis, we present a novel approach for stereo vision-based on-board and online Simultaneous Localization and Mapping (SLAM) for multi-robot teams given the challenges imposed by planetary exploration missions. We combine distributed local and decentralized global estimation methods to get the best of both worlds: A local reference filter on each robot provides real-time local state estimates required for robot control and fast reactive behaviors. We designed a novel graph topology to incorporate these state estimates into an online incremental graph optimization to compute global pose and map estimates that serve as input to higher-level autonomy functions. In order to model the 3D geometry of the environment, we generate dense 3D point cloud and probabilistic voxel-grid maps from noisy stereo data. We distribute the computational load and reduce the required communication bandwidth between robots by locally aggregating high-bandwidth vision data into partial maps that are then exchanged between robots and composed into global models of the environment. We developed methods for intra- and inter-robot map matching to recognize previously visited locations in semi- and unstructured environments based on their estimated local geometry, which is mostly invariant to light conditions as well as different sensors and viewpoints in heterogeneous multi-robot teams. A decoupling of observable and unobservable states in the local filter allows us to introduce a novel optimization: Enforcing all submaps to be gravity-aligned, we can reduce the dimensionality of the map matching from 6D to 4D. In addition to map matches, the robots use visual fiducial markers to detect each other. In this context, we present a novel method for modeling the errors of the loop closure transformations that are estimated from these detections. We demonstrate the robustness of our methods by integrating them on a total of five different ground-based and aerial mobile robots that were deployed in a total of 31 real-world experiments for quantitative evaluations in semi- and unstructured indoor and outdoor settings. In addition, we validated our SLAM framework through several different demonstrations at four public events in Moon and Mars-like environments. These include, among others, autonomous multi-robot exploration tests at a Moon-analogue site on top of the volcano Mt. Etna, Italy, as well as the collaborative mapping of a Mars-like environment with a heterogeneous robotic team of flying and driving robots in more than 35 public demonstration runs

    The Marketing of Electronic Cigarettes in the UK

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    First paragraph: Tobacco harm reduction has long been a public private partnership (PPP), with all the potential conflicts of interest between the two sectors that such arrangements bring. Until recently, however, this was a relatively simple PPP, between tobacco control and one private partner: the pharmaceutical industry. Now a combination of technical innovation and an energised debate about harm reduction has opened the territory to two new private sector operators: electronic cigarette (e-cigarette) companies and tobacco companies, which has stimulated a dramatic increase in commercial activity. This study was commissioned to examine these developments, and map out both current activity and likely future trends. It covered the period from May 2012 to June 2013, and comprised a systematic audit of all forms of e-cigarette marketing, as well as the related public relations and editorial comment in tobacco industry and retail trade press. Traditional and digital / social networking outlets were included. In addition, in-depth interviews were conducted with marketing experts to help make sense of what was a very extensive data set: 991 discrete items (editorial, images, online posts and advertising) were identified

    Seattle\u27s Seafaring Siren: A Cultural Approach to the Branding of Starbucks

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    Many corporate brands tend to be built on a strong foundation of culture, but very minimal research seems to indicate a thorough analysis of the role of an organizational\u27s culture in its entirety pertaining to large corporations. This study analyzed various facets of Starbucks Coffee Company through use of the cultural approach to organizations theory in order to determine if the founding principles of Starbucks are evident in their organizational culture. Howard Schultz\u27 book Onward was analyzed and documented as the key textual artifact in which these principles originated. Along with these principles, Starbucks\u27 Website, Facebook, Twitter and YouTube page were analyzed to determine how Starbucks\u27 culture was portrayed on these sites. The rhetorical analysis of Schultz\u27 book Onward conveyed that Starbucks\u27 culture is broken up into a professional portion and a personal portion, each overlapping one another in its principles. After sifting through various tweets, posts and videos, this study found that Starbucks has created a perfect balance of culture, which is fundamentally driven by their values and initiatives in coffee, ethics, relationships and storytelling. This study ultimately found that Starbucks\u27 organizational culture is not only carrying out their initiatives that they principally set out to perform, but they are also doing so across all platforms while engaging others to do the same. Based on these findings, this thesis aims to test the permeation of culture in corporate brands while posing a challenge for future research to classify social media sites as a part of culture. Also, the findings of this study propose a re-examination of Kennedy and Deal\u27s culture types in order to adapt to Web 2.0 and 3.0 technologies
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