Bruce, Matthew F.2014-03-142014-03-141993-08-19etd-11102009-020128http://hdl.handle.net/10919/45603Since the introduction of the Born and Rytov approximations for use in random wave propagation some forty years ago, a controversy has boiled over the regions of validity and relative merits of the methods. Although the methods fail for strong fluctuations and distant path lengths, these two perturbation methods are the only approaches available for weak fluctuations in a random in homogeneous media. The approximations have also been applied to the inverse problem for optical and acoustical tomography. The intent of this thesis is to investigate the work of previous authors and attempt to clarify the distinctions of each method. The conclusion will be reached that neither approximation is necessarily better than the other in general for all applications. A careful consideration of the problem following the points given should point towards the use of one approximation over the other.viii, 133 leavesBTDapplication/pdfenIn CopyrightLD5655.V855 1993.B779Approximation theoryBorn approximationWaves -- Mathematical modelsThesishttp://scholar.lib.vt.edu/theses/available/etd-11102009-020128/