DDI 3 Development at DDA

Diffusion Directions Imaging (DDI)

Di usion magnetic resonance imaging (dMRI) is the reference in vivo modality to study the connectivity of the brain white matter. Images obtained through dMRI are indeed related to the probability density function (pdf) of displacement of water molecules subject to restricted di usion in the brain white matter. The knowledge of this di usion pdf is therefore of primary importance. Several metho...

The DDI Approach to Morphology

DDI stands for “Don’t Do It.” White (1980) used the acronym DDI in a delightful paper on garbage collection. He argued 25 years ago that the garbage collector should be run rarely – perhaps once a year – if at all. That’s pretty much how many of us work these days. We buy enough memory so we don’t have to clean up more than once a week. Rebooting is easier than garbage collecting. As for disks,...

Locating the Geographic Center of DDI 3.0

2'-beta-fluoro-2',3'-dideoxyadenosine, lodenosine, in rhesus monkeys: plasma and cerebrospinal fluid pharmacokinetics and urinary disposition.

2'-beta-Fluoro-2',3'-dideoxyadenosine (F-ddA, lodenosine) is a nucleoside analog that was rationally designed as a more chemically and enzymatically stable anti-AIDS drug than its parent compound 2', 3'-dideoxyadenosine or didanosine. Plasma and cerebrospinal fluid (CSF) pharmacokinetics of this compound and its major metabolite, 2'-beta-fluoro-2',3'-dideoxyinosine (F-ddI), were studied in thre...

Optimizing DDA Code on a POWER5 Processor

In this paper we take an existing scientific computation code, DDA, and optimize it to run on an IBM Power5 processor. The DDA code, originally developed by a Ph.D. candidate in physics, suffers from excessive execution time caused by a high number of cache accesses and a low rate of instructions per cycle. Our goal is to improve the code’s performance by making a series of optimizations in a s...