From the webpage:
Multidimensional and String Indexes for Streaming Data
The Superlinear Index project is investigating how to data structures and algorithms for maintaining superlinear indexes on out-of-core storage (such as disk drives), with high incoming data rates. To understand what a superlinear index is, consider a linear index, which provides a total order on keys. A superlinear index is more complex than a total order. Examples of superlinear indexes including multidimensional indexes and full-text indexes.
A number of publications but none in 2012.
I will be checking to see if the project is still alive.