[a little more about my research...]
GEOPHYSICAL INVERSE
THEORY MATERIALS
Over the years I've been pulling together various geophysical inversion materials onto a geophysical inverse theory resources webpage to share with others. This began with my TAing a graduate-level geophysical inverse theory course and then continued with my substitute teaching in it in a later year. Contents include recommended reading lists, links to web resources, a few Matlab scripts, and my lecture notes. Students, researchers, and professors alike may find something useful or interesting in here.
NONLINEAR FILTERS & SMOOTHERS TUTORIAL
Part of my inverse theory research relies on concepts from recursive filters, so I had to take some time to come up to speed on those. In section 6.1 of the classic textbook Applied Optimal Estimation (Gelb ed., 1974) are two simple radar tracking examples used to demonstrate several nonlinear filters. I've programmed up a Matlab script to recompute those examples, and have added other filters to compare and contrast them in both linear and nonlinear cases. Maybe you'll find them useful yourself in comparing properties of various standard recursive filters and smoothers. Check it out!
ASA STUDENT COUNCIL
I was the student representative for the Underwater Acoustics section of the Acoustical Society of America (ASA) from June 2006 to Jan 2008, and continue to run the official student website for ASA, the "ASA Student Zone". Please check it out for the latest on your ASA student representatives and upcoming ASA meetings, including the next one in Paris, France!
Over the years I've been pulling together various geophysical inversion materials onto a geophysical inverse theory resources webpage to share with others. This began with my TAing a graduate-level geophysical inverse theory course and then continued with my substitute teaching in it in a later year. Contents include recommended reading lists, links to web resources, a few Matlab scripts, and my lecture notes. Students, researchers, and professors alike may find something useful or interesting in here.
NONLINEAR FILTERS & SMOOTHERS TUTORIAL
Part of my inverse theory research relies on concepts from recursive filters, so I had to take some time to come up to speed on those. In section 6.1 of the classic textbook Applied Optimal Estimation (Gelb ed., 1974) are two simple radar tracking examples used to demonstrate several nonlinear filters. I've programmed up a Matlab script to recompute those examples, and have added other filters to compare and contrast them in both linear and nonlinear cases. Maybe you'll find them useful yourself in comparing properties of various standard recursive filters and smoothers. Check it out!
ASA STUDENT COUNCIL
I was the student representative for the Underwater Acoustics section of the Acoustical Society of America (ASA) from June 2006 to Jan 2008, and continue to run the official student website for ASA, the "ASA Student Zone". Please check it out for the latest on your ASA student representatives and upcoming ASA meetings, including the next one in Paris, France!
WHAT
DOES ALL THAT STUFF MEAN?
A Quick Low-Down for the Layperson
The research group I'm in at APL studies the ocean bottom by analyzing sound waves (from sonar for example) that travel into it and bounce off of it. It's a bit like when you sing in a room with your eyes closed and you can tell by listening whether you're in a tile-walled bathroom or in a wood-walled sauna. Except in this case the "wall" is the seafloor, perhaps a quarter-mile below underwater, and we want to discern the composition and features of not only the seafloor surface, but what lies underneath it as well. I study seismology math, or "theoretical seismology", because seismologists do essentially this same work - they analyze surface recordings of earthquake waves which bounced and bent in layers inside the Earth, and from them estimate the composition and features inside the Earth. My research focus is theoretical rather than with measurements in the field - this math is all about estimating quantities that are measured indirectly, and my niche for my PhD thesis relates to improving the quality of those estimates in the ocean bottom problem. Finally, all this ties into my planetary interests because a growing number of the icy moons in our solar system (like some moons of Jupiter and Saturn) are found to likely have buried oceans on them, and seismology and underwater acoustics will probably be the first way those oceans will be studied.
A Quick Low-Down for the Layperson
The research group I'm in at APL studies the ocean bottom by analyzing sound waves (from sonar for example) that travel into it and bounce off of it. It's a bit like when you sing in a room with your eyes closed and you can tell by listening whether you're in a tile-walled bathroom or in a wood-walled sauna. Except in this case the "wall" is the seafloor, perhaps a quarter-mile below underwater, and we want to discern the composition and features of not only the seafloor surface, but what lies underneath it as well. I study seismology math, or "theoretical seismology", because seismologists do essentially this same work - they analyze surface recordings of earthquake waves which bounced and bent in layers inside the Earth, and from them estimate the composition and features inside the Earth. My research focus is theoretical rather than with measurements in the field - this math is all about estimating quantities that are measured indirectly, and my niche for my PhD thesis relates to improving the quality of those estimates in the ocean bottom problem. Finally, all this ties into my planetary interests because a growing number of the icy moons in our solar system (like some moons of Jupiter and Saturn) are found to likely have buried oceans on them, and seismology and underwater acoustics will probably be the first way those oceans will be studied.