Изкуствен интелект Упражнение № 2
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Transcript Изкуствен интелект Упражнение № 2
Изкуствен интелект
Упражнение № 6
спец. Информатика, ФМИ
2004/2005
Семантични мрежи и фрейми
Семантични мрежи
Фрейми
Семантични мрежи
Семантичните мрежи се състоят от
обекти и релации между обектите
Обикновено се представят чрез
граф, като възлите на графа
съответстват на обектите, а
релациите между обектите се
представят чрез именувани дъги
свързващи възлите на графа
Семантичнa мрежa
Семантичнa мрежa
Семантичнa мрежa
Основни типове връзки
Тип
Семантика
Пример
А Subset
B
А B
А Member
B
А B
is_a(bill,cats)
R ( А, B )
age(tom,12)
R
А
B
R
А
B
А B
R
x xАR(x, B)
subset(cats,mammals)
legs(birds,2).
x y x А y B R(x, y) parent(tom,an)
Семантична мрежа
animal
daylight
active_at
isa
bird
moving_method
albatross
kiwi
brown
Ross
black_&_white
walk
Kim
Albert
fly
night
isa(bird,animal).
isa(albatross,bird).
isa(kiwi,bird).
isa(ross,albatross).
isa(albert,albatross).
isa(kim,kiwi).
moving_method(bird,fly).
moving_method(kiwi,walk).
active_at(bird,daylight).
active_at(kiwi,night).
colour(albatross,black_&_white).
colour(kiwi,brown).
moving_method(X,Method):isa(X,SuperX),
moving_method(SuperX,Method).
(де)композиция на терм
+Term =.. ?List
?Term =.. +List
List е списък, чийто първи елемент е функтор на Term,
а останалите елементи на List са аргументите на този терм Term, т.е.
| ?- product(0, n, n-1) =.. L.
L = [product,0,n,n-1]
| ?- n-1 =.. L.
L = [-,n,1]
| ?- product =.. L.
L = [product]
| ?- X=..[functor,arg1,arg2,arg3,arg4].
X = functor(arg1,arg2,arg3,arg4) ?
Вместо този предикат може да се използват arg/3 и functor/3.
fact(Fact):Fact,!.
fact(Fact):Fact=..[Rel,Arg1,Arg2],
isa(Arg1,SuperArg),
SuperFact=..[Rel,SuperArg,Arg2],
fact(SuperFact).
| ?- fact(moving_method(kim,Method)).
Method = walk ?
| ?- fact(moving_method(albert,Method)).
Method = fly ?
Съпоставяне на семантични мрежи
figure
oval
circle
polygon
4-side
ellipse
rectangle
square
triangle
trapezoid
Съпоставяне на семантични мрежи
% is_a hierarchy
isa(square,rectangle).
isa(rectangle,4-side).
isa(trapezoid,4-side).
isa(parallelogram,4-side).
isa(circle,oval).
isa(ellipse,oval).
isa(triangle,polygon).
isa(4-side,polygon).
isa(polygon,figure).
isa(oval,figure).
Съпоставяне на семантични мрежи
c
c
Арка
a
b
a
b
support(a,c).
c
a
touch(a,b).
b
a
b
c
Съпоставяне на семантични мрежи
% Objects represented as facts in the format:
% object(Name,Parts,IsaRelations,
MustRelations,MustNotRelations
object(arch,[a,b,c],
[isa(a,4-side),isa(b,4-side), isa(c,polygon)],
[support(a,c),support(b,c)],
[touch(a,b)]).
Съпоставяне на семантични мрежи
% Test patterns
test1([X,Y,Z],
[isa(X,rectangle),isa(Y,rectangle),isa(Z,triangle)],
[support(X,Z),support(Y,Z)]).
test2([X,Y,Z],
[isa(X,rectangle),isa(Y,rectangle),isa(Z,triangle)],
[support(X,Z),support(Y,Z),touch(X,Y)]).
Съпоставяне на семантични мрежи
% Sample runs
?- match([X,Y,Z],
[isa(X,rectangle),isa(Y,rectangle),isa(Z,triangle)],
[support(X,Z),support(Y,Z)],
Name).
Name=arch
?- test1(Parts,Isa,Rels),match(Parts,Isa,Rels,Name).
Name=arch
Съпоставяне на семантични мрежи
match(Parts,Isa1,Rels,Name) :object(Name,Parts,Isa2,Must,MustNot),
match_isa(Isa1,Isa2),
subset(Must,Rels),
\+ intersect(Rels,MustNot).
Съпоставяне на семантични мрежи
match_isa([],[]).
match_isa([isa(X,P)|T],[isa(X,Q)|V]) :parent(P,Q),
match_isa(T,V).
Съпоставяне на семантични мрежи
subset([],_).
subset([X|T],Y) :member(X,Y),
subset(T,Y).
intersect(L1,L2) :member(X,L1),
member(X,L2).
Съпоставяне на семантични мрежи
parent(X,X).
parent(X,Z) :isa(X,Y),
parent(Y,Z).
Фрейми
Animals
rel(alive,animals,t).
rel(flies,animals,f).
Alive: T
subset(birds,animals).
Flies: F
Subset
subset(mammals,animals).
Subset
Birds
Mammals
rel(flies,birds,t).
Legs: 2
Legs: 4
rel(legs,birds,2).
Flies: T
Subset
Penguins
Subset
Cats
Flies: F
Subset
Bats
Legs: 2
Flies: T
Member
Member
Member
Opus
Bill
Pat
Name: Opus
Name: Bill
Name: Pat
Friend:
Friend:
rel(legs,mammals,4).
rel(legs,mammals,4).
Animals
subset(penguins,birds).
Alive: T
subset(cats,mammals).
Flies: F
Subset
subset(bats,mammals).
Subset
Birds
Mammals
rel(flies,penguins,f).
Legs: 2
Legs: 4
rel(legs,bats,2).
Flies: T
Subset
Penguins
Subset
Cats
Flies: F
Subset
Bats
Legs: 2
Flies: T
Member
Member
Member
Opus
Bill
Pat
Name: Opus
Name: Bill
Name: Pat
Friend:
Friend:
rel(flies,bats,t).
is_a(opus,penguins).
Animals
is_a(bill,cats).
Alive: T
is_a(pat,bats).
Flies: F
Subset
name(opus,'Opus').
Subset
Birds
Mammals
friend(opus,bill).
Legs: 2
Legs: 4
name(bill,'Bill').
Flies: T
Subset
Penguins
Subset
Cats
Flies: F
Subset
name(Pat,'Pat').
Bats
Legs: 2
Flies: T
Member
friend(bill,opus).
Member
Member
Opus
Bill
Pat
Name: Opus
Name: Bill
Name: Pat
Friend:
Friend:
Пример
FRAME: bird
a_kind_of: animal
moving_method: fly
active_at: daylight
Пример
FRAME: albatross
a_kind_of: bird
colour: black_and_white
size: 115 % 115 cm long
FRAME: kiwi
a_kind_of: bird
moving_method: walk
active_at: night
colour: brown
size: 40
Пример
FRAME: Albert
instance_of: albatross
size: 120
%
%
%
%
%
A frame is represented as a set of
Prolog facts:
frame_name(Slot,Value)
where Value is either a simple value or
a procedure
% Frame bird: the prototypical bird
bird(a_kind_of,animal).
bird(movin_method,fly).
bird(active_at,daylight).
% Frame albatross: albatross is a typical bird
% with some extra facts: it is black and white,
% and it is 115 cm long
albatross(a_kind_of, bird).
albatross(colour,black_and_white).
albatross(size,115).
% Frame kiwi: kiwi is a rather untypical
% bird in that it walks instead of flies,
% and it is active at night
kiwi(a_kind_of,bird).
kiwi(moving_method,walk).
kiwi(active_at,night).
kiwi(colour,brown).
kiwi(size,40).
% Frame albert: an instance of big albatross
albert(instance_of,albatross).
albert(size,120).
% Frame ross: an instance of baby albatross
ross(instance_ot,albatross).
ross(size,40).
% Frame animal: slot relative_size
% obtains its value by executing
% procedure relative_size
animal(relative_size,
execute(
relative_size(Object,Value),
Object,
Value
)
).
value(Frame,Slot,Value):Query=..[Frame,Slot,Value],
call(Query),!.
value(Frame,Slot,Value):parent(Frame,ParentFrame),
value(ParentFrame,Slot,Value).
parent(Frame,ParentFrame):(Query=..[Frame,a_kind_of,ParentFrame]
;
Query=..[Frame,instance_of,ParentFrame]),
call(Query).
?-value(albert,active_at,AlbertTime).
AlbertTime=daylight
?-value(kiwi,active_at,KiwiTime).
KiwiTime=night
% 40/115*100%=34.78%
?-value(ross,relative_size,R).
R=34.78
relative_size(Object,RelativeSize):value(Object,size,ObjSize),
value(Object,instance_of,ObjClass),
value(ObjClass,size,ClassSize),
RelativeSize is ObjSize/ClassSize*100.
animal(relative_size,
execute(
relative_size(Obj,Val),
Obj,
Val
)
).
value(Frame,Slot,Value):value(Frame,Frame,Slot,Value).
value(Frame,SuperFrame,Slot,Value):Query=..[SuperFrame,Slot,Information],
call(Query),
process(Information,Frame,Value).
value(Frame,SuperFrame,Slot,Value):parent(SuperFrame,ParentSuperFrame),
value(Frame,ParentSuperFrame,Slot,Value).
process(execute(Goal,Frame,Value),Frame,Value):-!,
call(Goal).
process(Value,_,Value).