Declarative interaction through
interactive planners
Conn V Copas
Defence Science & Technology Organisation
Australia
Ernest A Edmonds
Loughborough University of Technology
Great Britain
Defense Science & Tech. Org. 1
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Presentation aims
• To introduce concepts of planning and declarative
interaction
• To describe an implementation of an interactive
planner
– goal description languages
• To compare planning with HCI formalisms
– model-based UIMSs
– Petri nets
Defense Science & Tech. Org. 2
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Concepts of Planning - 1
A
C
A
B
B
Initial state:
(on C A) (on A Table) (on B Table)
C
Goal state:
(on A B) (on B C)
Operator definitions:
operator:
(move ?What ?From ?To)
precondition: (clear ?What) (clear ?To)
effect:
(on ?What ?To) (not (on ?What ?From))
(clear ?From) (not (clear ?To))
Defense Science & Tech. Org. 3
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Concepts of Planning - 2
Plan: (move C A Table) (move B Table C) (move A Table B)
• Planner searches (nondeteministically) for
operator combinations which will achieve the goal
• Operators could be user-level commands
• A form of automatic programming
Defense Science & Tech. Org. 4
CADUI'96 - 5-7 June 1996 - FUNDP Namur
A GIS goal
“I would like to see the roads data on a white background, containing a
legend in the bottom right corner and a scale-bar on top”
Defense Science & Tech. Org. 5
CADUI'96 - 5-7 June 1996 - FUNDP Namur
A GIS command line
d.mon start=x0
d.erase color=white
d.rast -o map=roads
d.scale at=0,0
d.frame frame=frame0 at=0,40,75,100
d.erase color=black
d.legend map=roads
• General purpose, low-level application
Defense Science & Tech. Org. 6
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Graphical GIS user interfaces
• Pull-down menus reflect the
command-line
• The interface reflects the
underlying programming
language
• Direct manipulation
possibilities limited by ability to
represent actions by gesture
Defense Science & Tech. Org. 7
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Declarative interaction
• Users describe goals; machine infers procedures
• Intelligent interfaces, or ‘just’ constraint
satisfaction?
• Planners as indirect manipulation
– acceptability?
Defense Science & Tech. Org. 8
CADUI'96 - 5-7 June 1996 - FUNDP Namur
UCPOP (Penberthy & Weld 92)
• Public-domain planner supporting conditional
effects, dynamic object universes, universal and
existential quantification
• Proveably sound and complete
–
–
–
–
–
regressive
first-principles
partial-order
domain-independent
closed world assumption; instantaneous effects
Defense Science & Tech. Org. 9
CADUI'96 - 5-7 June 1996 - FUNDP Namur
GIS domain knowledge
(:operator d-rast
:parameters (?container ?name ?data ?map)
:precondition (and (selected ?container ?name) (data ?data) )
:effect (and
(displayed-in ?container ?name map ?map)
(kind map ?map two-d)
(refers-to map ?map data ?data) )
(forall (?A ?B)
(when (displayed-in ?container ?name ?A ?B)
(not (displayed-in ?container ?name ?A ?B))))
(forall (?frame ?id ?X ?Y)
(when (and (contains ?container ?name ?frame ?id)
(displayed-in ?frame ?id ?X ?Y))
(not (displayed-in ?frame ?id ?X ?Y)) ))
(forall (?colour)
(when (background-colour ?container ?name ?colour)
(not (background-colour ?container ?name ?colour))))
(forall (?frame1 ?id1 ?colour1)
(when (and (contains ?container ?name ?frame1 ?id1)
(background-colour ?frame1 ?id1 ?colour1))
(not (background-colour ?frame1 ?id1 ?colour1)))) ))
Defense Science & Tech. Org. 10
“The d-rast command
requires a currently selected
container, and some data.
Its effects are that a map
is displayed in the container,
and that, if anything is
already displayed, then all
contents are overwritten”
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Goal description languages
:goal (exists (window ?x)
(exists (frame ?y)
(exists (scale-bar ?z)
(and
(background-colour ?x white)
(displayed-in ?x map roads)
(contains ?x ?y)
(position frame ?y "0 40 75 100")
(displayed-in ?y legend roads)
(displayed-in ?x scale-bar ?z)
(position scale-bar ?z "0 0") ))))
Defense Science & Tech. Org. 11
• problem of Lisp/Ucpop syntax
• problem of mastery of predicate
calculus: conjunction,
disjunction, negation, universal
quantification
• lack of guidance about possible
goal statements
• analogy with SQL: the language
is declarative, demanding, and
limited by its first-order nature
CADUI'96 - 5-7 June 1996 - FUNDP Namur
A GIS data model
DISPLAYED
IN
background
SCALE
BAR
position
WINDOW
DISPLAYED
IN
MAP
REFERS
TO
kind
CONTAINS
FRAME
position
DISPLAYED
IN
kind
DATA
LEGEND
REFERS
TO
• Planners model state transitions, with domain
structure only implicit
• Data model necessary for methodical UI design
Defense Science & Tech. Org. 12
CADUI'96 - 5-7 June 1996 - FUNDP Namur
A planner form-filling interface
• Resembles a graphical
data-base interface, but
with explicit quantifiers
• Irrelevant (to the user)
whether the plan is
retrieved or derived
• Possibility of sketching the
goal?
Defense Science & Tech. Org. 13
CADUI'96 - 5-7 June 1996 - FUNDP Namur
HCI specification
•
•
•
•
Individual UIMS, CSCW and TA models?
Specification causes inflexibility?
Run-time generation of dynamics as a solution
Formalisms:
–
–
–
–
–
transition networks
context-free grammars
event languages
production rules
Petri nets
Defense Science & Tech. Org. 14
CADUI'96 - 5-7 June 1996 - FUNDP Namur
HCI specification
•
•
•
•
Individual UIMS, CSCW and TA models?
Specification causes inflexibility?
Run-time generation of dynamics as a solution
Formalisms:
–
–
–
–
–
transition networks
context-free grammars
event languages
production rules
Petri nets
{
Defense Science & Tech. Org. 15
ATNs
causal models
high-level rules
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Uses of causal knowledge
+ projection
(UIDE)
Knowledge base
Operators
Model-based UIMS
+ path finding algorithm
Planner
preconditions
- progressive
effects
- regressive
+ dependency analysis
Predicate
transition net
Defense Science & Tech. Org. 16
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Dependency analysis
Operator-1
preconditions: A
effects: C,D
Operator-2
preconditions: B,C
effects: G
Operator-3
preconditions: D,E
effects: B,F
Defense Science & Tech. Org. 17
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Petri net challenges
• Why generate a net manually?
• Expressiveness
– conditional effects
– universal quantifiers
(also a problem for model-based UIMS)
• Ontological clarity
– inhibitor arcs? places? tokens?
• Scalable reachability analysis
Defense Science & Tech. Org. 18
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Conclusion
– Contemporary planners are sufficiently expressive and
have sufficient performance to support declarative
interaction
– Graphical goal description languages are possible
– Planning supports constraint satisfaction, as a general
solution to inflexible system dynamics
• Shortcomings
– performance (?)
– the formalist fantasy?
Defense Science & Tech. Org. 19
CADUI'96 - 5-7 June 1996 - FUNDP Namur
Any questions?
Defense Science & Tech. Org. 20
CADUI'96 - 5-7 June 1996 - FUNDP Namur