Matching Items (3)
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- All Subjects: Fault scarps
- All Subjects: marine robotics
- All Subjects: Volcanic Tableland
- Genre: Academic theses
- Creators: Das, Jnaneshwar
- Creators: Scott, Tyler
Description
Rock traits (grain size, shape, orientation) are fundamental indicators of geologic processes including geomorphology and active tectonics. Fault zone evolution, fault slip rates, and earthquake timing are informed by examinations of discontinuities in the displacements of the Earth surface at fault scarps. Fault scarps indicate the structure of fault zones fans, relay ramps, and double faults, as well as the surface process response to the deformation and can thus indicate the activity of the fault zone and its potential hazard. “Rocky” fault scarps are unusual because they share characteristics of bedrock and alluvial fault scarps. The Volcanic Tablelands in Bishop, CA offer a natural laboratory with an array of rocky fault scarps. Machine learning mask-Region Convolutional Neural Network segments an orthophoto to identify individual particles along a specific rocky fault scarp. The resulting rock traits for thousands of particles along the scarp are used to develop conceptual models for rocky scarp geomorphology and evolution. In addition to rocky scarp classification, these tools may be useful in many sedimentary and volcanological applications for particle mapping and characterization.
ContributorsScott, Tyler (Author) / Arrowsmith, Ramon (Thesis advisor) / Das, Jnaneshwar (Committee member) / DeVecchio, Duane (Committee member) / Arizona State University (Publisher)
Created2020
Description
The need for incorporating game engines into robotics tools becomes increasingly crucial as their graphics continue to become more photorealistic. This thesis presents a simulation framework, referred to as OpenUAV, that addresses cloud simulation and photorealism challenges in academic and research goals. In this work, OpenUAV is used to create a simulation of an autonomous underwater vehicle (AUV) closely following a moving autonomous surface vehicle (ASV) in an underwater coral reef environment. It incorporates the Unity3D game engine and the robotics software Gazebo to take advantage of Unity3D's perception and Gazebo's physics simulation. The software is developed as a containerized solution that is deployable on cloud and on-premise systems.
This method of utilizing Gazebo's physics and Unity3D perception is evaluated for a team of marine vehicles (an AUV and an ASV) in a coral reef environment. A coordinated navigation and localization module is presented that allows the AUV to follow the path of the ASV. A fiducial marker underneath the ASV facilitates pose estimation of the AUV, and the pose estimates are filtered using the known dynamical system model of both vehicles for better localization. This thesis also investigates different fiducial markers and their detection rates in this Unity3D underwater environment. The limitations and capabilities of this Unity3D perception and Gazebo physics approach are examined.
This method of utilizing Gazebo's physics and Unity3D perception is evaluated for a team of marine vehicles (an AUV and an ASV) in a coral reef environment. A coordinated navigation and localization module is presented that allows the AUV to follow the path of the ASV. A fiducial marker underneath the ASV facilitates pose estimation of the AUV, and the pose estimates are filtered using the known dynamical system model of both vehicles for better localization. This thesis also investigates different fiducial markers and their detection rates in this Unity3D underwater environment. The limitations and capabilities of this Unity3D perception and Gazebo physics approach are examined.
ContributorsAnand, Harish (Author) / Das, Jnaneshwar (Thesis advisor) / Yang, Yezhou (Committee member) / Berman, Spring M (Committee member) / Arizona State University (Publisher)
Created2020
Description
Drylands make up more than 45% of the Earth’s land surface and are essential to agriculture and understanding global carbon and elemental cycling. This thesis presents an analysis of atmospheric relative humidity (RH) and temperature (T) as they impact soil moisture and water content at two dryland sites. In particular, this thesis assesses the likelihood and impact of non-rainfall moisture (NRM) sources on dryland soils. This work also includes a discussion of the development and testing of a novel environmental sensing network, using custom nodes called EarthPods, and recommendations for the collection of future data from dryland sites to better understand NRM events in these regions. An analysis of weather conditions at two drylands sites suggest that nighttime RH is frequently high enough for NRM events to occur. Thesis results were unable to detect changes in soil water content based on historical weather data, likely due to instrument limitations (depth and sensitivity of soil moisture probes) and the small changes in soil moisture during NRM events. However, laboratory tests of EarthPod soil moisture sensors indicated strong sensitivity to T. Characterization of these T sensitivities provide opportunities to calibrate and correct soil moisture estimates using these sensors in the future. This work provides the foundation for larger biogeochemical sampling campaigns focusing on NRM in dryland systems.
ContributorsHanan, Desmond (Author) / Trembath-Reichert, Elizabeth (Thesis advisor) / Das, Jnaneshwar (Committee member) / Throop, Heather (Committee member) / Arizona State University (Publisher)
Created2021