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Now showing items 31-40 of 83
A planned approach to high collision risk area
(Massachusetts Institute of Technology, 2020)
This thesis examines the transition of a vessel from the open ocean, where collisions are rare, to a high risk and heavy traffic area such as a Traffic Separation Scheme (TSS). Previous autonomy approaches generally view ...
Morphological approaches to understanding Antarctic Sea ice thickness
(Massachusetts Institute of Technology, 2020)
Sea ice thickness has long been an under-measured quantity, even in the satellite era. The snow surface elevation, which is far easier to measure, cannot be directly converted into sea ice thickness estimates without ...
Extraction of uranium from seawater : Design and testing of a symbiotic system
(Massachusetts Institute of Technology, 2017)
Seawater is estimated to contain 4.5 billion tonnes of uranium, approximately 1000 times that available in conventional terrestrial resources. Finding a sustainable way to harvest uranium from seawater will provide a source ...
Controller design for underwater vehicle systems with communication constraints
(Massachusetts Institute of Technology, 2015)
Real-time cooperation between autonomous vehicles can enable time-critical missions such as tracking and pursuit of a dynamic target or environmental feature, but relies on wireless communications. Underwater, communication ...
Computational imaging and automated identification for aqueous environments
(Massachusetts Institute of Technology, 2011)
Sampling the vast volumes of the ocean requires tools capable of observing from a distance while retaining detail necessary for biology and ecology, ideal for optical methods. Algorithms that work with existing SeaBED AUV ...
Robust acoustic signal detection and synchronization in a time varying ocean environment
(Massachusetts Institute of Technology, 2012)
Signal detection and synchronization in the time varying ocean environment is a difficult endeavor. The current common methods include using a linear frequency modulated chirped pulse or maximal length sequence as a detection ...
Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves
(Massachusetts Institute of Technology, 2011)
This thesis describes the physics of fully three-dimensional low frequency acoustic interaction with internal waves, bottom sediment waves and surface swell waves that are often observed in shallow waters and on continental ...
Verification of a six-degree of freedom simulation model for the REMUS autonomous underwater vehicle
(Massachusetts Institute of Technology, 2001)
mproving the performance of modular, low-cost autonomous underwater vehicles (AUVs) in such applications as long-range oceanographic survey, autonomous docking, and shallow-water mine countermeasures requires improving the ...
Modeling wind forcing in phase resolving simulation of nonlinear wind waves
(Massachusetts Institute of Technology, 2010)
Wind waves in the ocean are a product of complex interaction of turbulent air flow with gravity driven water surface. The coupling is strong and the waves are non-stationary, irregular and highly nonlinear, which restricts ...
Estimation and tracking of rapidly time-varying broadband acoustic communication channels
(Massachusetts Institute of Technology, 2006)
This thesis develops methods for estimating wideband shallow-water acoustic communication channels. The very shallow water wideband channel has three distinct features: large dimension caused by extensive delay spread; ...