1 CADUI'96 - 5-7 June 1996 - FUNDP Namur Defense Science & Tech. Org. Declarative interaction...

1 CADUI'96 - 5-7 June 1996 - FUNDP Namur Defense Science & Tech. Org.

Declarative interaction through Declarative interaction through interactive plannersinteractive planners

Conn V CopasDefence Science & Technology Organisation

Australia

Ernest A EdmondsLoughborough University of Technology

Great Britain


Presentation aimsPresentation 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


Concepts of Planning - 1Concepts of Planning - 1

Initial state: Goal state:

(on C A) (on A Table) (on B Table) (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))

A

C

B C

B

A


Concepts of Planning - 2Concepts of Planning - 2Plan: (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


A GIS goalA 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”


A GIS command lineA 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


Graphical GIS user interfacesGraphical 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


Declarative interactionDeclarative interaction

• Users describe goals; machine infers procedures

• Intelligent interfaces, or ‘just’ constraint satisfaction?

• Planners as indirect manipulation– acceptability?


UCPOP (Penberthy & Weld 92)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


GIS domain knowledgeGIS 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)))) ))

“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”


Goal description languagesGoal description languages• 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

: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") ))))


A GIS data modelA GIS data model

• Planners model state transitions, with domain structure only implicit

• Data model necessary for methodical UI design

WINDOW

DISPLAYED IN

DISPLAYED IN

SCALEBAR

MAP

position

kind

CONTAINS FRAME DISPLAYED IN

LEGEND

position

background

REFERS TO

REFERS TO

DATA

kind


A planner form-filling interfaceA 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?


HCI specificationHCI 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


HCI specificationHCI 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 ATNs

– Petri nets causal models

high-level rules{


Uses of causal knowledgeUses of causal knowledge

Operators

preconditions

effects

Knowledge base

Planner

- progressive

- regressive

+ path finding algorithm

Model-based UIMS

(UIDE)

+ projection

Predicate

transition net

+ dependency analysis


Dependency analysisDependency analysisOperator-1

preconditions: A

effects: C,D

Operator-3

preconditions: D,E

effects: B,F

Operator-2

preconditions: B,C

effects: G


Petri net challengesPetri 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


ConclusionConclusion– 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?


Any questions?

1 CADUI'96 - 5-7 June 1996 - FUNDP Namur Defense Science & Tech. Org. Declarative interaction...

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Transcript of 1 CADUI'96 - 5-7 June 1996 - FUNDP Namur Defense Science & Tech. Org. Declarative interaction...