FLAT2D: Fast localization from approximate transformation into 2D

Many autonomous vehicles require precise localization into a prior map in order to support planning and to leverage semantic information within those maps (e.g. that the right lane is a turn-only lane.) A popular approach in automotive systems is to use infrared intensity maps of the ground surface to localize, making them susceptible to failures when the surface is obscured by snow or when the road is repainted. An emerging alternative is to localize based on the 3D structure around the vehicle; these methods are robust to these types of changes, but the maps are costly both in terms of storage and the computational cost of matching. In this paper, we propose a fast method for localizing based on 3D structure around the vehicle using a 2D representation. This representation retains many of the advantages of "full" matching in 3D, but comes with dramatically lower space and computational requirements. We also introduce a variation of Graph-SLAM tailored to support localization, allowing us to make use of graph-based error-recovery techniques in our localization estimate. Finally, we present real-world localization results for both an indoor mobile robotic platform and an autonomous golf cart, demonstrating that autonomous vehicles do not need full 3D matching to accurately localize in the environment

Policy-Based Planning for Robust Robot Navigation

This thesis proposes techniques for constructing and implementing an extensible navigation framework suitable for operating alongside or in place of traditional navigation systems. Robot navigation is only possible when many subsystems work in tandem such as localization and mapping, motion planning, control, and object tracking. Errors in any one of these subsystems can result in the robot failing to accomplish its task, oftentimes requiring human interventions that diminish the benefits theoretically provided by autonomous robotic systems. Our first contribution is Direction Approximation through Random Trials (DART), a method for generating human-followable navigation instructions optimized for followability instead of traditional metrics such as path length. We show how this strategy can be extended to robot navigation planning, allowing the robot to compute the sequence of control policies and switching conditions maximizing the likelihood with which the robot will reach its goal. This technique allows robots to select plans based on reliability in addition to efficiency, avoiding error-prone actions or areas of the environment. We also show how DART can be used to build compact, topological maps of its environments, offering opportunities to scale to larger environments. DART depends on the existence of a set of behaviors and switching conditions describing ways the robot can move through an environment. In the remainder of this thesis, we present methods for learning these behaviors and conditions in indoor environments. To support landmark-based navigation, we show how to train a Convolutional Neural Network (CNN) to distinguish between semantically labeled 2D occupancy grids generated from LIDAR data. By providing the robot the ability to recognize specific classes of places based on human labels, not only do we support transitioning between control laws, but also provide hooks for human-aided instruction and direction. Additionally, we suggest a subset of behaviors that provide DART with a sufficient set of actions to navigate in most indoor environments and introduce a method to learn these behaviors from teleloperated demonstrations. Our method learns a cost function suitable for integration into gradient-based control schemes. This enables the robot to execute behaviors in the absence of global knowledge. We present results demonstrating these behaviors working in several environments with varied structure, indicating that they generalize well to new environments. This work was motivated by the weaknesses and brittleness of many state-of-the-art navigation systems. Reliable navigation is the foundation of any mobile robotic system. It provides access to larger work spaces and enables a wide variety of tasks. Even though navigation systems have continued to improve, catastrophic failures can still occur (e.g. due to an incorrect loop closure) that limit their reliability. Furthermore, as work areas approach the scale of kilometers, constructing and operating on precise localization maps becomes expensive. These limitations prevent large scale deployments of robots outside of controlled settings and laboratory environments. The work presented in this thesis is intended to augment or replace traditional navigation systems to mitigate concerns about scalability and reliability by considering the effects of navigation failures for particular actions. By considering these effects when evaluating the actions to take, our framework can adapt navigation strategies to best take advantage of the capabilities of the robot in a given environment. A natural output of our framework is a topological network of actions and switching conditions, providing compact representations of work areas suitable for fast, scalable planning.PhDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/144073/1/rgoeddel_1.pd

Yerba Mate in Argentina: A Cultural Reflection and Projection through a Popular Pastime

Yerba mate is a popular tea-like beverage widely consumed in many South American countries, including Paraguay, Brazil, and Argentina. Originally discovered and consumed by Paraguayan natives, mass production of yerba mate did not begin until the arrival of the Spanish in the sixteenth century. Its cultivation techniques developed over time, allowing production to spread to other countries including Argentina, today´s largest producer of yerba mate. In Argentina, yerba mate has evolved from simply being a stimulating beverage into a clear reflection of the country’s culture and values. The uses of yerba mate in Argentine literature – Jorge Luis Borges, Julio Cortázar, tango lyrics – demonstrate the beverage’s importance to everyday life and societal norms. Further connections between yerba and Argentine culture include straw-sharing with tactile communication, appetite-suppression with high beauty standards, and caffeine content with busy city life and laborious country work. These ideas are explored in this paper in order to assert that yerba mate’s own qualities project key aspects of Argentine culture, solidifying its continued popularity for years to come

Heterogenisation of ketone catalysts within mesoporous supports for asymmetric epoxidation

The synthesis of the first mesoporous silica (150 Å) anchored carbohydrate-derived chiral ketone is described. This new heterogeneous catalyst has been shown to be effective in the asymmetric epoxidation of olefins by oxone. The heterogeneous ketone catalyst has comparable activity to that of its homogeneous counterpart and returned enantioselectivities up to 90% e.e

A Literacy Photostory: Improving Classroom Literacy Instruction

In rapidly changing times, students need to understand and utilize various types of literacies in order to be productive citizens and communicate with each other in a fast-paced world. Literacy is often simplified to the ability to read and write, only on some occasions including other topics such as speaking and listening skills, or computer literacies. The need for improved literacy instruction is apparent in high schools, and this study seeks to inform educators of different needs and hopes that students may have in the broad field of literacy. This study seeks to expand the definition of literacy while simultaneously starting a conversation about ways to better incorporate literacy instruction into schools

NF-κB-inducing kinase regulates selected gene expression in the Nod2 signaling pathway

The innate immune system surveys the extra- and intracellular environment for the presence of microbes. Among the intracellular sensors is a protein known as Nod2, a cytosolic protein containing a leucine-rich repeat domain. Nod2 is believed to play a role in determining host responses to invasive bacteria. A key element in upregulating host defense involves activation of the NF-κB pathway. It has been suggested through indirect studies that NF-κB-inducing kinase, or NIK, may be involved in Nod2 signaling. Here we have used macrophages derived from primary explants of bone marrow from wild-type mice and mice that either bear a mutation in NIK, rendering it inactive, or are derived from NIK(−/−) mice, in which the NIK gene has been deleted. We show that NIK binds to Nod2 and mediates induction of specific changes induced by the specific Nod2 activator, muramyl dipeptide, and that the role of NIK occurs in settings where both the Nod2 and TLR4 pathways are activated by their respective agonists. Specifically, we have linked NIK to the induction of the B-cell chemoattractant known as BLC and suggest that this chemokine may play a role in processes initiated by Nod2 activation that lead to improved host defense

The Development and Evaluation of Graphite-Matrix Fuel Compacts for the HTGR

>A summary of development and evaluation of graphitematrix fuel compacts for the high-temperature gas-cooled reactor is presented. The fuel compacts consist of Th-- U dicarbide particles dispersed in a high-density graphite matrix and are produced by a hot-pressing process. Compacts prepared from Th--U oxide, Th-- U silicide, and Th--U dicarbide coated with pyrolytic C were subjected to radiation and fission-product-retention testing. Results of these tests are included and are discussed in detail. (J.R.D.

An Investigation of the Manganese Indium System

A preliminary phase-equilibria study has been made of the manganese-indium alloy system by means of thermal analysis (cooling curves) and metallographic studies (photomicrographs). Ferromagnetism has been found to exist in alloys containing up to 70 atom percent manganese and has tentatively been attributed to the compound Mn2In. A phase diagram has been proposed, on the basis of the data obtained, in which the indium rich portion of the system consists of indium plus Mn2In, while the manganese rich portion is made up of a manganese solid solution. Additional experiments have been outlined to further identify the nature and extent of the phases present. A new scheme of chemical analysis has been applied to the alloys with good success