Machine Learning For Planetary Mining Applications

Robotic mining could prove to be an efficient method of mining resources for extended missions on the Moon or Mars. One component of robotic mining is scouting an area for resources to be mined by other robotic systems. Writing controllers for scouting can be difficult due to the need for fault tolerance, inter-agent cooperation, and agent problem solving. Reinforcement learning could solve these problems by enabling the scouts to learn to improve their performance over time. This work is divided into two sections, with each section addressing the use of machine learning in this domain. The first contribution of this work focuses on the application of reinforcement learning to mining mission analysis. Various mission parameters were modified and control policies were learned. Then agent performance was used to assess the effect of the mission parameters on the performance of the mission. The second contribution of this work explores the potential use of reinforcement learning to learn a controller for the scouts. Through learning, these scouts would improve their ability to map their surroundings over time

Examining the Safety and Cost of Risk-Reducing Salpingectomies as Prophylactic Treatment for Women Seeking Sterilization Who Are at Low to Moderate Risk for Ovarian Cancer

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.Ovarian cancer ranks fifth among the most common cause of cancer deaths in women. There is evidence that the site of origin for the majority of the most serious form of ovarian cancers is the fallopian tube. There is growing consensus for risk-reducing salpingectomies (RRS) to be performed for women who are at moderate risk for developing ovarian cancer especially at a time of patient desired sterilization. A retrospective chart review to determine the safety and cost of risk-reducing salpingectomies in comparison to tubal ligations was performed using the Healthcare Cost and Utilization Project inpatient database from 2008-2012. Results showed no significant difference between each procedure for length of stay in days (95%CI -0.19, 0.79 p: 0.24) or intraoperative complications (OR 4.84 (95%CI 0.38, 60.9 p: 0.22)). There was a significant difference between the total charges associated with each procedure with tubal ligation having a mean cost of $2,227.21 (95$403.2, $4051.10) and the bilateral salpingectomy procedure having a mean cost of$11,189.80 (95%CI $6,582.70,$15,796.80 p<0.001). The cost difference between the two procedures should shift the conversation towards the question of whether hospital billing and insurance coverage for bilateral salpingectomy without oophorectomy should be examined more closely in order to provide RRS as a prophylactic treatment for women at moderate risk for developing ovarian cancer seeking sterilization.This item is part of the College of Medicine - Phoenix Scholarly Projects 2019 collection. For more information, contact the Phoenix Biomedical Campus Library at [email protected]

Estimating Mass of Inflatable Aerodynamic Decelerators Using Dimensionless Parameters

This paper describes a technique for estimating mass for inflatable aerodynamic decelerators. The technique uses dimensional analysis to identify a set of dimensionless parameters for inflation pressure, mass of inflation gas, and mass of flexible material. The dimensionless parameters enable scaling of an inflatable concept with geometry parameters (e.g., diameter), environmental conditions (e.g., dynamic pressure), inflation gas properties (e.g., molecular mass), and mass growth allowance. This technique is applicable for attached (e.g., tension cone, hypercone, and stacked toroid) and trailing inflatable aerodynamic decelerators. The technique uses simple engineering approximations that were developed by NASA in the 1960s and 1970s, as well as some recent important developments. The NASA Mars Entry and Descent Landing System Analysis (EDL-SA) project used this technique to estimate the masses of the inflatable concepts that were used in the analysis. The EDL-SA results compared well with two independent sets of high-fidelity finite element analyses

Discrete Data Transfer Technique for Fluid-Structure Interaction

This paper presents a general three-dimensional algorithm for data transfer between dissimilar meshes. The algorithm is suitable for applications of fluid-structure interaction and other high-fidelity multidisciplinary analysis and optimization. Because the algorithm is independent of the mesh topology, we can treat structured and unstructured meshes in the same manner. The algorithm is fast and accurate for transfer of scalar or vector fields between dissimilar surface meshes. The algorithm is also applicable for the integration of a scalar field (e.g., coefficients of pressure) on one mesh and injection of the resulting vectors (e.g., force vectors) onto another mesh. The author has implemented the algorithm in a C++ computer code. This paper contains a complete formulation of the algorithm with a few selected results

Topology and Grid Adaption for High-Speed Flow Computations

This study investigates the effects of grid topology and grid adaption on numerical solutions of the Navier-Stokes equations. In the first part of this study, a general procedure is presented for computation of high-speed flow over complex three-dimensional configurations. This includes the grid generation and solution algorithm for Navier-Stokes equations in a general three-dimensional curvilinear coordinate system. The flow field is simulated on the surface of a Butler wing in a uniform stream. Results are presented for Mach number 3.5 and a Reynolds number of 2,000,000. The O-type and H-type grids have been used for this study, and the results are compared together and with other theoretical and experimental results. The results demonstrate that while the H-type grid is suitable for the leading and trailing edges, a more accurate solution can be obtained for the middle part of the wing with an O-type grid. In spite of some discrepancies, the present numerical results compare favorably with the experimental results. In the second part of this study, methods of grid adaption are reviewed and a method is developed with the capability of adapting to several variables. This method is based on a variational approach and is an algebraic method. Also, the method has been formulated in such a way that there is no need for any matrix inversion. This method is used in conjunction with the calculation of hypersonic flow over a blunt-nose body. A movie has been produced which shows simultaneously the transient behavior of the solution and the grid adaption. For both cases, the simulations are done by integrating the viscous Navier-Stokes equations. These equations govern the unsteady, viscous, compressible and heat-conducting flow of an ideal gas, and all viscous terms are retained. The equations are written in curvilinear coordinates so that the body surface is represented accurately. The computer codes are written in FORTRAN, is vectorized and currently run on the CDC Vector Processing System (VPS-32, CYBER 205) computer. The results indicate the viability and validity of the proposed methods

A Multidisciplinary Tool for Systems Analysis of Planetary Entry, Descent, and Landing (SAPE)

SAPE is a Python-based multidisciplinary analysis tool for systems analysis of planetary entry, descent, and landing (EDL) for Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Titan. The purpose of SAPE is to provide a variable-fidelity capability for conceptual and preliminary analysis within the same framework. SAPE includes the following analysis modules: geometry, trajectory, aerodynamics, aerothermal, thermal protection system, and structural sizing. SAPE uses the Python language-a platform-independent open-source software for integration and for the user interface. The development has relied heavily on the object-oriented programming capabilities that are available in Python. Modules are provided to interface with commercial and government off-the-shelf software components (e.g., thermal protection systems and finite-element analysis). SAPE runs on Microsoft Windows and Apple Mac OS X and has been partially tested on Linux

Earth Entry Vehicle Design for Sample Return Missions Using M-SAPE

Most mission concepts that return sample material to Earth share one common element: an Earth entry vehicle (EEV). The primary focus of this paper is the examination of EEV design space for relevant sample return missions. Mission requirements for EEV concepts can be divided into three major groups: entry conditions (e.g., velocity and flight path angle), payload (e.g., mass, volume, and g-load limit), and vehicle characteristics (e.g., thermal protection system, structural topology, and landing concepts). The impacts of these requirements on the EEV design have been studied with an integrated system analysis tool, and the results will be discussed in details. In addition, through sensitivities analyses, critical design drivers that have been identified will be reviewed