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From: puget@ilog.ilog.fr (Jean-Francois Puget)
Subject: Re: Problem: Constraint Based Scheduling
Message-ID: <1995May14.195632.1830@ilog.fr>
To: smithd@BOREALIS.CS.UREGINA.CA (Donald Smith)
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Date: Sun, 14 May 95 19:56:32 GMT
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In article <smithd.800249825@borealis>, smithd@BOREALIS.CS.UREGINA.CA (Donald Smith) writes:
|> 
|>  I am working on my MSc thesis where I am examining some heuristics
|> for Constraint based intelligent scheduling.  My implementation
|> language is CLP(FD) and my chosen scheduling domain is the classic 
|> "job shop" model.
|> 
|>  I'm having some problems trying to scientifically "interpret" my 
|> results.
|> 
|>  For example, given that scheduling is NP hard, and assuming
|> I'm using examples "large" enough that a proof of optimality
|> is not feasable, how can I verify the effectiveness of a 
|> heuristic?  I've read several papers on scheduling with
|> large examples, but everyone seems to "dance" around the
|> issue by comparing their Scheduler output against the
|> output of other peoples schedulers, never mentioning
|> if their solution is even in the same magnitude as an optimal
|> solution.

Some people are interested by optimality...

I suggest that you look at the following papers:

\itemitem{1.} D. Applegate and W. Cook, ``A Computational Study of the
Job-Shop Sched-uling Problem,'' {\em ORSA Journal on Computing} {\bf 3}
(1991) 149-156.

\itemitem{4.} J. Carlier and E. Pinson, ``A Practical Use of Jackson's
Preemptive Schedule for Solving the Job-Shop Problem,'' {\em Annals of
Operations Research} {\bf 26} (1990) 269-287.

\itemitem{5.} J. Carlier and E. Pinson, ``Adjustment of Heads and
Tails for the Job-Shop Problem,'' {\em European Journal of Operational
Research} {\bf 78} (1994) 146-161.


\bibitem[Caseau and Laburthe, 1994] {Caseau 94}
Yves Caseau and Fran\c{c}ois Laburthe.
Improved CLP Scheduling with Task Intervals.
In {\em Proceedings of the Eleventh International Conference on Logic
Programming,} Santa Margherita Ligure, Italy, 1994.

Other papers are available on our web server: http://www.ilog.com

Select ILOG SCHEDULE in the product section, then select the following
papers:

TECHNICAL REPORT 95-03

A Theoretical and Experimental Comparison of Constraint Propagation
Techniques for Disjunctive Scheduling

DVI file : ijcai95.dvi
PS file  : ijcai95.ps
Authors  : Philippe Baptiste and Claude Le Pape
Also in  : Proceedings of the Fourteenth International Joint
	   Conference on Artificial Intelligence, Montreal, Quebec,
	   1995.

TECHNICAL REPORT 95-02

Incorporating Efficient Operations Research Algorithms in
Constraint-Based Scheduling

DVI file : aior95.dvi
PS file  : aior95.ps
Authors  : Philippe Baptiste, Claude Le Pape and Wim Nuijten
Also in  : Proceedings of the First International Joint Workshop on
	   Artificial Intelligence and Operations Research, Timberline
	   Lodge, Oregon, 1995.

TECHNICAL REPORT 95-01

Disjunctive Constraints for Manufacturing Scheduling: Principles and
Extensions

DVI file : iccim95.dvi
PS file  : iccim95.ps
Authors  : Philippe Baptiste and Claude Le Pape
Also in  : Proceedings of the Third International Conference on
	   Computer Integrated Manufacturing, Singapore, 1995.

I hope this helps

-- 
  Jean-Francois Puget		 net : puget@ilog.fr
  ILOG S.A.                      url : http://www.ilog.fr
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