From mm4b+ at andrew.cmu.edu  Tue Aug 20 11:38:05 1996
From: mm4b+ at andrew.cmu.edu (Michael Matessa)
Date: Tue, 20 Aug 1996 11:38:05 -0400 (EDT)
Subject: new ACT-R web page
Message-ID: <8m6RjR_00YUq028Aw0@andrew.cmu.edu>

The ACT-R group in Groningen has a new homepage at
http://tcw2.ppsw.rug.nl/act-r

If anyone else has an ACT-R related page, please send email to
webmaster at sands.psy.cmu.edu so it can be linked to the CMU page.


From Andre_Mayers at uqac.uquebec.ca  Tue Aug 20 23:42:33 1996
From: Andre_Mayers at uqac.uquebec.ca (Andre Mayers)
Date: Wed, 21 Aug 1996 03:42:33 GMT
Subject: problem with the derivation of the parameter q (p. 66)
Message-ID: <321a7d78.53759933@132.212.12.12>

Good day,

I am writing my thesis, and I spent the last two days trying  to find
out the missing step. If some body can explain  the equation 3.15, 
I will be very grateful. The problem is that  the probability of
failure given  the considered production is 

	                                  P(F, D, E)
P(F | D,E) =  ----------------------------------- 
                          P(F, D, E) + P(S, D, E) 


but the equation 3.15 gives (as far as I can see)

	                                  P(F, D)
P(F | D,E) =  ----------------------------------- 
                          P(F, D) + P(S, D, E) 

some body know why  ?

Thank you

Andre Mayers
Universite de Montreal


From ja+ at CMU.EDU  Wed Aug 21 09:20:28 1996
From: ja+ at CMU.EDU (John Anderson)
Date: Wed, 21 Aug 1996 09:20:28 -0400 (EDT)
Subject: problem with the derivation of the parameter q (p. 66)
In-Reply-To: <321a7d78.53759933@132.212.12.12>
References: <321a7d78.53759933@132.212.12.12>
Message-ID: <0m6koQq00iV_E1D2Ub@andrew.cmu.edu>

Gee, I had to dredge up old memories:

The implicit assumption underlying Equation 3.15 is P(E|D,F) = 1 for all
E which is to say that if one keeps working at an unsolvable problem one
will eventually wind up expending any amount of effort E.  In contrast.

P(E1|S,D) < P(E2|S,D) if E1 > E2

which is to say that one eventually solves a solvable problem and stops
putting effort in.

In any case, since P(E|D,F) = 1, P(F,D,E) = P(F,D) and from that one can
substitute into Mayer's equations. 


From cl+ at andrew.cmu.edu  Wed Aug 28 11:22:22 1996
From: cl+ at andrew.cmu.edu (Christian J Lebiere)
Date: Wed, 28 Aug 1996 11:22:22 -0400 (EDT)
Subject: Research Programmer Position Available
Message-ID: <Mm96EiK00WBLI3MHxY@andrew.cmu.edu>


                  Department of Psychology
                 Carnegie Mellon University

            Research Programmer Position Available

We are  looking for  a AI  programmer to work on  development  of 
the  ACT-Rproduction  system and its  application to  intelligent 
tutoring  systems.  One  project will be  to develop  a graphical 
user interface to the ACT-Rsystem to help domain experts generate 
examples of  problem-solving.  The ACT-R analogy mechanism  would 
transform these examples into  production rules which  would form 
the basis of a model which would be used in tutoring students.


The programmer would work under the supervision of John Anderson.
A background in artificial intelligence and cognitive science is
desirable.  

Interested applicants should send resumes to:

    Helen Borek
    Psychology Department - BH345C
    Carnegie Mellon University
    Pittsburgh, PA  15213 


or via fax at (412) 268-2844.