Learning and Searching Methods for Robust, Real-Time Visual Odometry.

Accurate position estimation provides a critical foundation for mobile robot perception and control. While well-studied, it remains difficult to provide timely, precise, and robust position estimates for applications that operate in uncontrolled environments, such as robotic exploration and autonomous driving. Continuous, high-rate egomotion estimation is possible using cameras and Visual Odometry (VO), which tracks the movement of sparse scene content known as image keypoints or features. However, high update rates, often 30~Hz or greater, leave little computation time per frame, while variability in scene content stresses robustness. Due to these challenges, implementing an accurate and robust visual odometry system remains difficult. This thesis investigates fundamental improvements throughout all stages of a visual odometry system, and has three primary contributions: The first contribution is a machine learning method for feature detector design. This method considers end-to-end motion estimation accuracy during learning. Consequently, accuracy and robustness are improved across multiple challenging datasets in comparison to state of the art alternatives. The second contribution is a proposed feature descriptor, TailoredBRIEF, that builds upon recent advances in the field in fast, low-memory descriptor extraction and matching. TailoredBRIEF is an in-situ descriptor learning method that improves feature matching accuracy by efficiently customizing descriptor structures on a per-feature basis. Further, a common asymmetry in vision system design between reference and query images is described and exploited, enabling approaches that would otherwise exceed runtime constraints. The final contribution is a new algorithm for visual motion estimation: Perspective Alignment Search~(PAS). Many vision systems depend on the unique appearance of features during matching, despite a large quantity of non-unique features in otherwise barren environments. A search-based method, PAS, is proposed to employ features that lack unique appearance through descriptorless matching. This method simplifies visual odometry pipelines, defining one method that subsumes feature matching, outlier rejection, and motion estimation. Throughout this work, evaluations of the proposed methods and systems are carried out on ground-truth datasets, often generated with custom experimental platforms in challenging environments. Particular focus is placed on preserving runtimes compatible with real-time operation, as is necessary for deployment in the field.PhDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113365/1/chardson_1.pd

Designing Smooth Motions of Rigid Objects: Computing Curves in Lie Groups

Consider the problem of designing the path of a camera in 3D. As we may identify each camera position with a member of the Euclidean motions, SE(3), the problem may be recast mathematically as constructing interpolating curves on the (non-Euclidean) space SE(3). There exist many ways to formulate this problem, and indeed many solutions. In this thesis we shall examine solutions based on simple geometric constructions, with the goal of discovering well behaved and computable solutions. In affine spaces there exist elegant solutions to the problem of curve design, which are collectively known as the techniques of Computer Aided Geometric Design (CAGD). The approach of this thesis will be the generalization of these methods and an examination of computation on matrix Lie groups. In particular, the Lie groups SO(3) and SE(3) will be examined in some detail

A Study of the Cooperative Practices Involving the Use of Selected Secondary Public School Facilities by the Recreation Commissions in Rural Minnesota

The purpose of this study was to survey the use of selected public secondary schools by the recreation commissions in rural Manitoba, to determine the amount of, or lack of, cooperative practices between the school district and the recreation commission in these communities, in regard to the commission\u27s use of the school for community recreation. A single group non-probability sample of all school superintendents from the rural communities in southern Manitoba, that had a recreation commission and a population of between 800 and 4000 people was employed in this study. The questionnaire method was used with a questionnaire constructed by the writer and validated in a pilot study. The scale of measurement was considered to be nominal, with the type of statistics being descriptive and non-parametric. The Chi Square Test was employed to test the significant difference between the observed and the expected responses. The level of confidence selected to test was the .05 level. The data showed significantly that the majority of the school^ were being used to a limited extent for community recreation but a lack of established practices and policies in such areas as: contract}: forms for school usage, liabilities of the user and administrative planning seemed to be limiting the recreation commissions\u27 use of the school. The study hypothesis was therefore accepted; the more cooperative practices between the school district and the recreation commission involving the commission\u27s usage of the school for community recreation, the more available the school would be for recreation. The writer recommended that these communities should require that a school official be on the recreation commission and that the school board and the recreation commission should meet periodically to plan and promote the recreational use of the school

Agent-based Computational Demography and Beyond using JAS-mine

In this chapter we provide a hands-on guide on how to build a microsimulation using JAS-mine, a Java-based platform that provides unique simulation tools for discrete-event simulations, including both agent-based and microsimulation models. After presenting the rationale for the recent developments of the JAS-mine project and the main architectural choices made, we illustrate a step-by-step implementation of a rich dynamic microsimulation, which includes demographic processes (birth, death, household formation and dissolution) and other life course events (educational choices, labour market participation and employment outcomes).</p

MicroRNA-184 - An Ally in Calcium Signalling in the Skin

The skin provides a protective barrier against environmental, mechanical and microbial assault throughout life. Extracellular calcium (Ca2+) regulates the behavior of keratinocytes, the cells that form the epidermal layer of the skin. Calcium-dependent keratinocyte differentiation has been linked to microRNAs (miRNAs), small non-coding RNA molecules that attenuate gene output through mechanisms that culminate in target mRNA degradation. However, the impact of store-operated calcium entry (SOCE) on keratinocyte miRNA expression has received little attention. Here, I present our recent findings showing a relationship between SOCE and the induction of miRNA-184 (miR-184) in keratinocyte differentiation and migration. Levels of miR-184, barely detectable in untreated cells, rose by about 30-fold after keratinocytes were exposure to 1.5 mM Ca2+ for 5 days. Pharmacologic and genetic inhibitors of SOCE abrogated Ca2+-dependent miR-184 induction by 70%. Further, modulation of miR-184 levels using an exogenous miR-184 mimic or inhibitor enabled us to elucidate roles for miR-184 in keratinocyte differentiation. These include induction of involucrin, an important component of differentiating keratinocytes, elevation of p21 cyclin-dependent kinase (CDK) inhibitor and enhancement of DNA damage, as evidenced by higher levels of γH2AX, a marker of DNA double strand breaks. In addition, I will present our data implicating miR-184 in keratinocyte migration. We observed a 50-fold increase in miR-184 upon wounding keratinocyte monolayers. This occurred under routine low Ca2+ culture conditions, suggesting that high extracellular Ca2+is not an obligatory requirement for SOCE-dependent miR-184 induction. The induction of miR-184 in wounded monolayers was completely abolished in the presence of pharmacologic SOCE inhibitors. Transfection of keratinocytes with a miR-184 mimic stimulated migration in scratch assays, whereas the converse was observed when a miR-184 inhibitor was used. Together, these findings suggest miR-184 functions downstream of SOCE to promote differentiation and migration of epidermal keratinocytes

Brass Chamber Ensembles

Coached by Ross Wlater, Rex Richardson, and Kevin Malone

Chamber Brass Recital

Chamber Brass Recital Featurnng ensembles coached by Rex Richardson, Patrick Smith, and Ross Walte