Newsgroups: comp.ai.jair.announce
Path: cantaloupe.srv.cs.cmu.edu!bb3.andrew.cmu.edu!newsfeed.pitt.edu!news.duq.edu!newsgate.duke.edu!zombie.ncsc.mil!nntp.coast.net!newsfeed.dacom.co.kr!usenet.dacom.co.kr!news.postech.ac.kr!usenet.kornet.nm.kr!ames!cnn.nas.nasa.gov!eos!kronos.arc.nasa.gov!jair-ed
From: jair-ed@ptolemy.arc.nasa.gov
Subject: New Article, Accelerating Partial-Order Planners: Some ...
Message-ID: <1996Sep30.181400.7999@ptolemy-ethernet.arc.nasa.gov>
Originator: jair-ed@polya.arc.nasa.gov
Lines: 40
Sender: usenet@ptolemy-ethernet.arc.nasa.gov (usenet@ptolemy.arc.nasa.gov)
Nntp-Posting-Host: polya.arc.nasa.gov
Organization: NASA/ARC Computational Sciences Division
Date: Mon, 30 Sep 1996 18:14:00 GMT
Approved: jair-ed@ptolemy.arc.nasa.gov

JAIR is pleased to announce the publication of the following article:

Gerevini, A. and Schubert, L. (1996)
  "Accelerating Partial-Order Planners: Some Techniques for Effective Search 
   Control and Pruning", Volume 5, pages 95-137.

   Available in Postscript (401K) and compressed Postscript (164K). Two online 
   appendices (source code, domain description) are also available (68K and 47K).

   For quick access via your WWW browser, use this URL:
     http://www.cs.washington.edu/research/jair/abstracts/gerevini96a.html
   More detailed instructions are below.

Abstract: We propose some domain-independent techniques for bringing
well-founded partial-order planners closer to practicality. The first
two techniques are aimed at improving search control while keeping
overhead costs low.  One is based on a simple adjustment to the
default A* heuristic used by UCPOP to select plans for refinement. The
other is based on preferring ``zero commitment'' (forced) plan
refinements whenever possible, and using LIFO prioritization
otherwise. A more radical technique is the use of operator parameter
domains to prune search. These domains are initially computed from the
definitions of the operators and the initial and goal conditions,
using a polynomial-time algorithm that propagates sets of constants
through the operator graph, starting in the initial conditions.
During planning, parameter domains can be used to prune nonviable
operator instances and to remove spurious clobbering threats.  In
experiments based on modifications of UCPOP, our improved plan and
goal selection strategies gave speedups by factors ranging from 5 to
more than 1000 for a variety of problems that are nontrivial for the
unmodified version. Crucially, the hardest problems gave the greatest
improvements. The pruning technique based on parameter domains often
gave speedups by an order of magnitude or more for difficult problems,
both with the default UCPOP search strategy and with our improved
strategy. The Lisp code for our techniques and for the test problems
is provided in on-line appendices.

The article is available via:
   
 -- comp.ai.jair.papers (also see comp.ai.jair.announce)

 -- World Wide Web: The URL for our World Wide Web server is
       http://www.cs.washington.edu/research/jair/home.html
    For direct access to this article and related files try:
       http://www.cs.washington.edu/research/jair/abstracts/gerevini96a.html

 -- Anonymous FTP from either of the two sites below.

    Carnegie-Mellon University (USA):
	ftp://p.gp.cs.cmu.edu/usr/jair/pub/volume5/gerevini96a.ps
    The University of Genoa (Italy):
	ftp://ftp.mrg.dist.unige.it/pub/jair/pub/volume5/gerevini96a.ps

    The compressed PostScript file is named gerevini96a.ps.Z (164K)
    Two online appendices are available, named gerevini96a-appendix1 
    and gerevini96a-appendix2 (68K and 47K).

 -- automated email. Send mail to jair@cs.cmu.edu or jair@ftp.mrg.dist.unige.it
    with the subject AUTORESPOND and our automailer will respond. To
    get the Postscript file, use the message body GET volume5/gerevini96a.ps 
    (Note: Your mailer might find this file too large to handle.) 
    To obtain the online appendices, use the body:
    GET  volume5/gerevini96a-appendix1 
    or 
    GET  volume5/gerevini96a-appendix2

    Only one can file be requested in each message.

 -- JAIR Gopher server: At p.gp.cs.cmu.edu, port 70. 

For more information about JAIR, visit our WWW or FTP sites, or
send electronic mail to jair@cs.cmu.edu with the subject AUTORESPOND
and the message body HELP, or contact jair-ed@ptolemy.arc.nasa.gov.



