http://www.stathead.com/bbeng/woolner/statglossary.htm

Statistics Glossary
by Keith Woolner

Projection Systems

Vladimir 
A projection system for hitters developed by Gary Huckabay of the Baseball
Prospectus.   Vladimir is based on neural nets, using inputs such as age,
walk rate, batting average, power, and level (A/AA/AAA/Majors).   It seems to
do a better job than the STATS projections in predicting breakout and
collapse seasons, though it tends to be less accurate than STATS overall.
 The Vlads are published annually in the Prospectus.

WFG 
A pitcher projection system created by the Baseball Prospectus's Gary
Huckabay.   The acronym stands for "Wild F* Guess", an indication that the
creator considers is, ah... errr...., experimental.  :-).  WFG is not a
neural net like Vladimir, but is, in the words of the Prospectus, "a melange
of ad hoc algorithms that try to isolate reasons for increased or decreased
performance and the likelihood of injury".

BrockN (Brock2, Brock6, etc) 
A series of projection systems invented by Bill James and now maintained by
STATS, Inc.   The Brock2 method was published in an early abstract, and code
for generating Brock2 career trajectories is available in Sean Lahman's
Baseball Archive.  The latest Brock projections are available in various
annual STATS publications, most notably the STATS Major League Handbook.

XAN5 
An as-yet unpublished projection system being developed at Stathead.