I've added 5 dissertations to the incomplete list of MIR related PhDs. I'm particularly happy that Markus, Tomoyasu, and Kazuyoshi (all of them are former colleagues of mine) finished their thesis so successfully.
Tomoyasu Nakano recently finished his thesis on "A Study on Developing Applications Systems Based on Singing Understanding and Singing Expression" (in Japanese). He has now joined Masataka Goto's research group as a postdoc and is working on the CrestMuse project. He recently received a lot of attention for his work on optimizing Vocaloid parameters.
Kazuyoshi Yoshii recently finished his thesis on "Studies on Hybrid Music Recommendation Using Timbral and Rhythmic Features". Kazuyoshi was awarded a tenure position at the AIST which is pretty impressive. He joined Masataka's group and is working on CrestMuse.
Markus Schedl recently finished his thesis on "Automatically Extracting, Analyzing, and Visualizing Information on Music Artists from the World Wide Web". As part of his thesis he crawled a very impressive number of web pages to build a retrieval system for 600,000 artists. In the next months he'll be finishing his business studies.
Steven Travis Pope's thesis is already a bit older (2005) and serves as perfect example of how incomplete the list of PhDs is which I maintain. His work was on "Software Models and Frameworks for Sound Composition, Synthesis, and Analysis: The Siren, CSL, and MAK Music Languages".
The 5th PhD thesis I added to the list is Matt Wright's work on "Computer-Based Music Theory and Acoustics" which he completed at CCRMA, Stanford University.