[ RadSafe ] Deterministic, Stochastic, Etc.

[JPreisig at aol.com]

Dear Radsafe:
 
 
     This is from:    _jpreisig at aol.com_ (mailto:jpreisig at aol.com)         .
 
 
     Howdy radsafers.  Hope you all are  having a good week at work.
 
     Before I get into this message in a serious  way,  I'd like to 
communicate the information
that some research experience programs for young people (former NSF summer  
programs???) don't
really take place so much in high school anymore, but seem to be taking  
place as REU's ---
Research Experiences for Undergraduates --- and occur sometime during USA  
undergraduate
years.  Do a websearch...
 
 
      Recent postings to radsafe seem to indicate  some sort of either/or 
relationship for Stochastic
and/or Deterministic Processes.  While this can happen and be modelled  
appropriately, a full
model of many physical processes will include BOTH deterministic and  
stochastic terms.
See. for example, books on State-Space Modelling (Electrical Engineering),  
Optimal Estimation,
Kalman Filtering and the like.  Such modelling is done in Rocket and  
Airplane/Jet Guidance and/or
Control systems and is also done in Mathematics, Physics, Geophysics,  Etc. 
 Relevant books
include those by R. Grover Brown, Jazwinski, Gelb, JV Candy and many  
others.  Jazwinski is a 
difficult book with some math theory.  I'm not looking to train anyone  
into becoming a rocket
scientist here, but much of this e-mail goes well beyond traditional Health 
 Physics
training.
 
     In some aeronautics applications, deterministic  terms are used to 
describe linear
accelerations, velocities and translations, and also rotational  
accelerations, angular orientation
of a rocket/jet in space (roll, pitch and yaw), etc.  These parameters  can 
also have
stochastic terms, which describe noise processes (kind of like radiation  
background),
unmodelled physical effects, etc.  White noise is one type of noise as  
well a integrated white
noise and other noise terms.  Stochastic Noise is also sometimes  
introduced into Kalman 
Filtering systems to keep the filter running, so they don't close up.
 
     I guess in Radiation Biology, Health Physics,  etc., the biophysical 
systems are quite different,
and by their very size, could start to include nano-scale (and/or quantum  
mechanical) effects.
One could readily envision systems where deterministic effects are  
relatively small.  Stochastic
processes would dominate any computer modelling and/or measurement  studies.
YET, I would suggest with a quote by some academic whose name I barely  
remember "The more
you study random processes, the less random they become."
 
     What this all means for various radiation  threshold models, I don't 
know.  MODEL SYSTEMS AS
COMPLETELY AS POSSIBLE.  KISS also (Keep It Simple Stu---}.   And as 
Einstein once said
(and I don't have his exact quote here) --- Model things simply, but not  
overly (and incorrectly)
simply.  Data fitting is important.
 
     I smile a bit as I read on RADSAFE about a Low  Level Waste Storage 
facility opening in Texas.
I once did modelling for a LLRW facility in New Jersey.  One  Texas 
facility for much of the USA's 
LLRW????   Hmmm.  Sounds like trucking/hauling companies are  going to be 
making
a few dollars on this one.
 
     The second edition of Cahn and Goldhaber's  Experimental Foundations 
of Particle Physics
just showed up at my front door.  I recommend reading it for people  
interested in such things.
Time to disappear into the new, next three or four chapters.
 
     Apparently, Fermilab has new-found life for the  next three or four 
years, to try and better define
the energy of the Higgs particle... pretty cool, huh????
 
     Maybe Mr. Obama could re-awaken the  USA proton supercollider in Texas 
(or elsewhere),
so we could compete  with the folks at CERN.   Have a good  weekend.
 
 
             Regards,    Joseph R. (Joe) Preisig, PhD