No description available.

No description available.

No description available.

This thesis deals with the characterization of the dependence on the flow geometry of the streamwise fluctuations of the stagnation point of vortex breakdown in axisymmetric tubes and over delta wing aircraft. The statistical analysis presented herein shows that in an axisymmetric tube the 'darting' about the mean stagnation point are distributed normally for the two Reynolds numbers: ReD = 230,000 and 300,000 (independently of the Reynolds number in the range noted). The darting over a delta wing is not only non-Gaussian but also exhibits rather large localized fluctuations (Strouhal numbers ranging from 0.04 to 0.1), presumably due to the strong influence of the surrounding flow and the geometrical conditions: increase of circulation along the trailing edge, the abrupt separation of flow at the base of the delta wing, and other protuberances that emerge from the upper and lower surfaces of the wing (support elements in laboratory and stabilizers on delta wing aircraft). It is concluded that the behavior of vortex breakdown is strongly dependent on the surrounding geometry and that only experiments in axisymmetric tubes can provide the purest form of vortex breakdown for numerical simulations and analytical studies towards the understanding of the internal turbulence and its spectrum within the breakdown bubble for theoretical and industrial purposes. / US Navy (USN) author.

The purpose of the study was to construct and standardize a point-control test to be used to determine beginning fencing ability in a bouting situation. The specific problem was to determine the reliability and validity of the point-control test.

The camera is the cheapest and computationally real-time option for detecting or segmenting the environment for an autonomous vehicle, but it does not provide the depth information and is undoubtedly not reliable during the night, bad weather, and tunnel flash outs. The risk of an accident gets higher for autonomous cars when driven by a camera in such situations. The industry has been relying on LiDAR for the past decade to solve this problem and focus on depth information of the environment, but LiDAR also has its shortcoming. The industry methods commonly use projections methods to create a projection image and run detection and localization network for inference, but LiDAR sees obscurants in bad weather and is sensitive enough to detect snow, making it difficult for robustness in projection based methods. We propose a novel pointwise and Instance segmentation deep learning architecture for the point clouds focused on self-driving application. The model is only dependent on LiDAR data making it light invariant and overcoming the shortcoming of the camera in the perception stack. The pipeline takes advantage of both global and local/edge features of points in points clouds to generate high-level feature. We also propose Pointer-Capsnet which is an extension of CapsNet for small 3D point clouds.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Physics. / Vita. / Includes bibliographical references. / by Jeffrey F. Nicoll. / Ph.D.

No description available.

In the study of differential equations there are two fundamental questions: is there a solution? and what is it? One of the most elegant ways to prove that an equation has a solution is to pose it as a fixed point problem, that is, to find a function f such that x is a solution if and only if f (x) = x. Results from fixed point theory can then be employed to show that f has a fixed point. However, the results of fixed point theory are often nonconstructive: they guarantee that a fixed point exists but do not help in finding the fixed point. Thus these methods tend to answer the first question, but not the second. One such result is Schauder’s fixed point theorem. This theorem is broadly applicable in proving the existence of solutions to differential equations, including the Navier-Stokes equations under certain conditions. Recently a semi-constructive proof of Schauder’s theorem was developed in Rizzolo and Su (2007). In this thesis we go through the construction in detail and show how it can be used to search for multiple solutions. We then apply the method to a selection of differential equations.