Adaptive Object-Oriented Software Technology is loaded with 
Ph.D. thesis topics. My book (see below) gives an introduction to this
improved OO technology. Seven theses have already been written on this
topic. Here is a partial list of possible topics:

Aspect-Oriented Programming with crosscutting class graphs
  Each aspect is formulated with respect to a class graph.
  Multiple aspects that crosscut each other.

Distributed Adaptive Programming

Mechansisms to Specify the Range of Applicability
  of Adaptive Programs

Develop further Aspects besides Structure, Synchronization and
Remote Invocation.

Real-time Adaptive Software

Specification and Correctness Proofs for Adaptive Programs
  when is an adaptive program correct?

Type Theory for Adaptive Programming

Complexity Theory of Adaptive Programming
  what is the running time of a program parameterized by a class graph?

General purpose AO languages
  improve on AspectJ and Aspectual Collaborations
  http://www.ccs.neu.edu/research/demeter/biblio/aspectual-comps.html

Dynamic Aspectual Collaborations
  allow collaborations and adapters to be added and removed at run-time

Partially evaluate DJ programs
  DJ programs are slow. Partially evaluate them when class graphs 
  and strategies and visitors are fixed.

TRAVERSAL EQUIVALENCE PROBLEM:
Given two strategy/class graph pairs (S1,G1) and (S2,G2) such that
Common = Objects(G1) intersect Objects(G2) is not empty,
determine whether they define the same traversals for all objects
in Common. (Also treat the case where the question is whether one
is always a subtraversal of the other.) If the traversals are different
for some objects, give an object where the traversals are different.

Motivation: during the evolution of adaptive programs and class graphs,
we need to know how traversals change.      
etc.

AP AND TRANSLATOR GENERATION
How can we view an adaptive program as a generator of
translators for objects? Given an adaptive program p and
two class graphs C1 and C2 with which p works, how can we
produce a generator that translates C1-objects to C2-objects?

Some of those topics are addressed in my book.

====== BOOK INFORMATION
Title: 		Adaptive Object-Oriented Software: 
  		  The Demeter Method with Propagation Patterns
Author: 	Karl Lieberherr
Publisher: 	PWS Publishing Company
ISBN: 		0-534-94602-X
Year:		1996

For more information, including the foreword by Gregor Kiczales and 
John Lamping from Xerox PARC plus some sample chapters, see URL:
 		 http://www.ccs.neu.edu/research/demeter/

The Demeter Tools are a useful addition to the book. They are freely
available in object form. See URL:
		ftp://ftp.ccs.neu.edu/pub/people/lieber/DemeterTools.txt