Logic and Knowledge Representation K n o w l e d g e r e - - PowerPoint PPT Presentation

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Logic and Knowledge Representation K n o w l e d g e r e - - PowerPoint PPT Presentation

Logic and Knowledge Representation K n o w l e d g e r e p r e s e n t a t i o n , O n t o l o g i e s , S e m a n t i c We b 2 5 M a y 2 0 1 8 g s i l e n o @e n s t . f r G i


slide-1
SLIDE 1

Logic and Knowledge Representation

G i

  • v

a n n i S i l e n

  • g

s i l e n

  • @e

n s t . f r

T é l é c

  • m

P a r i s T e c h , P a r i s

  • D

a u p h i n e U n i v e r s i t y

K n

  • w

l e d g e r e p r e s e n t a t i

  • n

, O n t

  • l
  • g

i e s , S e m a n t i c We b

2 5 M a y 2 1 8

slide-2
SLIDE 2

What is Knowledge?

  • K

n

  • w

l e d g e i s w h a t w e a s c r i b e t

  • a

n a g e n t t

  • p

r e d i c t h i s b e h a v i

  • u

r u s i n g p r i n c i p l e s

  • f

r a t i

  • n

a l i t y .

N e w e l l , A . ( 1 9 8 2 ) . T h e K n

  • w

l e d g e L e v e l . A r t i fj c i a l I n t e l l i g e n c e , 1 8 ( 1 ) , 8 7 – 1 2 7 .

slide-3
SLIDE 3

What is Knowledge?

  • K

n

  • w

l e d g e i s w h a t w e a s c r i b e t

  • a

n a g e n t t

  • p

r e d i c t h i s b e h a v i

  • u

r u s i n g p r i n c i p l e s

  • f

r a t i

  • n

a l i t y .

– e

x a m p l e

  • f

r a t i

  • n

a l i t y p r i n c i p l e : I f a c

  • u

r s e

  • f

a c t i

  • n

l e a d t

  • m

y g

  • a

l , I w i l l t a k e t h a t c

  • u

r s e

  • f

a c t i

  • n

.

N e w e l l , A . ( 1 9 8 2 ) . T h e K n

  • w

l e d g e L e v e l . A r t i fj c i a l I n t e l l i g e n c e , 1 8 ( 1 ) , 8 7 – 1 2 7 .

slide-4
SLIDE 4

What is Knowledge?

  • K

n

  • w

l e d g e i s w h a t w e a s c r i b e t

  • a

n a g e n t t

  • p

r e d i c t h i s b e h a v i

  • u

r u s i n g p r i n c i p l e s

  • f

r a t i

  • n

a l i t y .

– e

x a m p l e

  • f

r a t i

  • n

a l i t y p r i n c i p l e : I f a c

  • u

r s e

  • f

a c t i

  • n

l e a d t

  • m

y g

  • a

l , I w i l l t a k e t h a t c

  • u

r s e

  • f

a c t i

  • n

. N

  • t

e : k n

  • w

l e d g e r e p r e s e n t a t i

  • n
  • n

l y r e p r

  • d

u c e s t h a t w h i c h w e a s c r i b e ; i t i s n

  • t

i n t e n d e d t

  • b

e a c c u r a t e , p h y s i c a l m

  • d

e l

N e w e l l , A . ( 1 9 8 2 ) . T h e K n

  • w

l e d g e L e v e l . A r t i fj c i a l I n t e l l i g e n c e , 1 8 ( 1 ) , 8 7 – 1 2 7 .

slide-5
SLIDE 5

Data, Information, Knowledge

  • D

a t a : u n i n t e r p r e t e d s i g n a l s

  • r

s y m b

  • l

s

slide-6
SLIDE 6

Data, Information, Knowledge

  • D

a t a : u n i n t e r p r e t e d s i g n a l s

  • r

s y m b

  • l

s

  • I

n f

  • r

m a t i

  • n

: d a t a w i t h a d d e d m e a n i n g

slide-7
SLIDE 7

Data, Information, Knowledge

  • D

a t a : u n i n t e r p r e t e d s i g n a l s

  • r

s y m b

  • l

s

  • I

n f

  • r

m a t i

  • n

: d a t a w i t h a d d e d m e a n i n g

  • K

n

  • w

l e d g e : a l l d a t a a n d i n f

  • r

m a t i

  • n

t h a t p e

  • p

l e u s e t

  • a

c t , a c c

  • m

p l i s h t a s k s a n d t

  • c

r e a t e n e w i n f

  • r

m a t i

  • n

( k n

  • w
  • h
  • w

,

  • w

h y ,

  • w

h

  • ,
  • w

h e r e a n d

  • w

h e n ) .

slide-8
SLIDE 8

Data, Information, Knowledge

D a t a : . . .

  • .

. . I n f

  • r

m a t i

  • n

: i t i s a m e s s a g e s a y i n g S O S K n

  • w

l e d g e : e m e r g e n c y s i g n a l , s t a r t r e s c u e

  • p

e r a t i

  • n

. D a t a : 1 4 5 4 3 1 2 I n f

  • r

m a t i

  • n

: i t i s a t e l e p h

  • n

e n u m b e r

  • f

a p e r s

  • n

K n

  • w

l e d g e : t

  • m

a k e a n a p p

  • i

n t m e n t I n e e d t

  • c

a l l i t

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SLIDE 9

Types of knowledge

  • E

x p l i c i t , c

  • n

s c i

  • u

s a n d e x t e r n a l , i n f

  • c

u s

  • I

m p l i c i t , m a y b e e x t e r n a l i z e d , n

  • t

i n f

  • c

u s

  • T

a c i t ,

  • f

t e n n

  • t

c

  • n

s c i

  • u

s , i n t e r n a l ( P

  • l

a n y i )

P i c t u r e f r

  • m

B r

  • h

m , R . ( 2 7 ) . B r i n g i n g P

  • l

a n y i

  • n

t h e T h e a t r e S t a g e

slide-10
SLIDE 10

More types of knowledge

  • P

r

  • c

e d u r a l k n

  • w

l e d g e : p r

  • c

e d u r e s , p l a n s

  • D

e c l a r a t i v e k n

  • w

l e d g e : c

  • n

c e p t s ,

  • b

j e c t s , f a c t s

slide-11
SLIDE 11

More types of knowledge

  • P

r

  • c

e d u r a l k n

  • w

l e d g e : p r

  • c

e d u r e s , p l a n s

  • D

e c l a r a t i v e k n

  • w

l e d g e : c

  • n

c e p t s ,

  • b

j e c t s , f a c t s

  • H

e u r i s t i c k n

  • w

l e d g e : e x p e r i e n c e , d e f a u l t s

  • K

n

  • w

l e d g e a b

  • u

t u n c e r t a i n t y : p r

  • b

a b i l i t y e s t i m a t i

  • n

s , d e f a u l t s , k n

  • w

i n g w h a t y

  • u

k n

  • w
slide-12
SLIDE 12

More types of knowledge

  • P

r

  • c

e d u r a l k n

  • w

l e d g e : p r

  • c

e d u r e s , p l a n s

  • D

e c l a r a t i v e k n

  • w

l e d g e : c

  • n

c e p t s ,

  • b

j e c t s , f a c t s

  • H

e u r i s t i c k n

  • w

l e d g e : e x p e r i e n c e , d e f a u l t s

  • K

n

  • w

l e d g e a b

  • u

t u n c e r t a i n t y : p r

  • b

a b i l i t y e s t i m a t i

  • n

s , d e f a u l t s , k n

  • w

i n g w h a t y

  • u

k n

  • w
  • C
  • m

m

  • n
  • s

e n s e k n

  • w

l e d g e : g e n e r a l c

  • n

c e p t s a n d t h e

  • r

i e s , g e n e r a l t a x

  • n
  • m

i e s a n d m e r e

  • n
  • m

i e s

slide-13
SLIDE 13

More types of knowledge

  • P

r

  • c

e d u r a l k n

  • w

l e d g e : p r

  • c

e d u r e s , p l a n s

  • D

e c l a r a t i v e k n

  • w

l e d g e : c

  • n

c e p t s ,

  • b

j e c t s , f a c t s

  • H

e u r i s t i c k n

  • w

l e d g e : e x p e r i e n c e , d e f a u l t s

  • K

n

  • w

l e d g e a b

  • u

t u n c e r t a i n t y : p r

  • b

a b i l i t y e s t i m a t i

  • n

s , d e f a u l t s , k n

  • w

i n g w h a t y

  • u

k n

  • w
  • C
  • m

m

  • n
  • s

e n s e k n

  • w

l e d g e : g e n e r a l c

  • n

c e p t s a n d t h e

  • r

i e s , g e n e r a l t a x

  • n
  • m

i e s a n d m e r e

  • n
  • m

i e s

  • Me

t a

  • k

n

  • w

l e d g e : k n

  • w

l e d g e a b

  • u

t k n

  • w

l e d g e t y p e s a n d t h e i r u s e

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SLIDE 14

What is Knowledge Representation?

R . D a v i s , H . S h r

  • b

e , a n d P . S z

  • l
  • v

i t s . Wh a t i s a K n

  • w

l e d g e R e p r e s e n t a t i

  • n

? A I M a g a z i n e , 1 4 ( 1 ) : 1 7

  • 3

3 , 1 9 9 3 .

a s i m p l i fj e d r e p r e s e n t a t i

  • n

r e i f y i n g

  • u

r a t t e n t i

  • n

t

  • t

h e w

  • r

l d a n d a m

  • d

e l

  • f

a s s

  • c

i a t e d r e a s

  • n

i n g p r

  • c

e s s e s t h a t i s a c c e s s i b l e t

  • p

r

  • g

r a m s a n d t

  • p

e

  • p

l e

slide-15
SLIDE 15

What is Knowledge Representation?

  • s

u r r

  • g

a t e

  • e

x p r e s s i

  • n
  • f
  • n

t

  • l
  • g

i c a l c

  • m

m i t m e n t

  • t

h e

  • r

y

  • f

i n t e l l i g e n t r e a s

  • n

i n g

  • m

e d i u m

  • f

e ffj c i e n t c

  • m

p u t a t i

  • n
  • m

e d i u m

  • f

h u m a n e x p r e s s i

  • n

R . D a v i s , H . S h r

  • b

e , a n d P . S z

  • l
  • v

i t s . Wh a t i s a K n

  • w

l e d g e R e p r e s e n t a t i

  • n

? A I M a g a z i n e , 1 4 ( 1 ) : 1 7

  • 3

3 , 1 9 9 3 .

a s i m p l i fj e d r e p r e s e n t a t i

  • n

r e i f y i n g

  • u

r a t t e n t i

  • n

t

  • t

h e w

  • r

l d a n d a m

  • d

e l

  • f

a s s

  • c

i a t e d r e a s

  • n

i n g p r

  • c

e s s e s t h a t i s a c c e s s i b l e t

  • p

r

  • g

r a m s a n d t

  • p

e

  • p

l e

slide-16
SLIDE 16

Knowledge systems

slide-17
SLIDE 17

if flower and seed then phanerogam if phanerogam and bare-seed then fir if phanerogam and 1-cotyledon then monocotyledonous if phanerogam and 2-cotyledon then dicotyledonous if monocotyledon and rhizome then thrush if dicotyledon then anemone if monocotyledon and ¬rhizome then lilac if leaf and flower then cryptogamous if cryptogamous and ¬root then foam if cryptogamous and root then fern if ¬leaf and plant then thallophyte if thallophyte and chlorophyll then algae if thallophyte and ¬ chlorophyll then fungus if ¬leaf and ¬flower and ¬plant then colibacille

Example of expert system

rhizome + flower + seed + 1-cotyledon ?

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SLIDE 18

From expert systems to KBS

  • E

x p e r t s y s t e m s S e p a r a t e k n

  • w

l e d g e ( r u l e s ) f r

  • m

t h e r e a s

  • n

i n g e n g i n e

slide-19
SLIDE 19

From expert systems to KBS

  • E

x p e r t s y s t e m s S e p a r a t e k n

  • w

l e d g e ( r u l e s ) f r

  • m

t h e r e a s

  • n

i n g e n g i n e

  • K

n

  • w

l e d g e

  • b

a s e d s y s t e m s S e p a r a t e k n

  • w

l e d g e ( c

  • n

c e p t s ) f r

  • m

r u l e s a n d r e a s

  • n

i n g

– e

x a m p l e : F r a m e s

  • s

t e r e

  • t

y p e d s t r u c t u r e s

  • f

k n

  • w

l e d g e

slide-20
SLIDE 20

From expert systems to KBS

  • E

x p e r t s y s t e m s S e p a r a t e k n

  • w

l e d g e ( r u l e s ) f r

  • m

t h e r e a s

  • n

i n g e n g i n e

  • K

n

  • w

l e d g e

  • b

a s e d s y s t e m s S e p a r a t e k n

  • w

l e d g e ( c

  • n

c e p t s ) f r

  • m

r u l e s a n d r e a s

  • n

i n g

– e

x a m p l e : F r a m e s

  • s

t e r e

  • t

y p e d s t r u c t u r e s

  • f

k n

  • w

l e d g e

– e

x a m p l e : S e m a n t i c n e t w

  • r

k s

  • r

e p r e s e n t a t i

  • n

b y g r a p h

  • b

a s e d f

  • r

m a l i s m

  • m
  • d

e l e n t i t i e s a n d t h e i r r e l a t i

  • n

s

slide-21
SLIDE 21

Frames

  • F

r a m e s a r e " s t e r e

  • t

y p e d " k n

  • w

l e d g e u n i t s r e p r e s e n t i n g s i t u a t i

  • n

s ,

  • b

j e c t s

  • r

e v e n t s

  • r

( c l a s s e s ) s e t s

  • f

s u c h e n t i t i e s .

slide-22
SLIDE 22

Frames

  • F

r a m e s a r e " s t e r e

  • t

y p e d " k n

  • w

l e d g e u n i t s r e p r e s e n t i n g s i t u a t i

  • n

s ,

  • b

j e c t s

  • r

e v e n t s

  • r

( c l a s s e s ) s e t s

  • f

s u c h e n t i t i e s .

  • A

f r a m e i s a c

  • l

l e c t i

  • n
  • f

a t t r i b u t e s ( s l

  • t

s ) , s p e c i fj e d b y f a c e t s t h a t c

  • r

r e s p

  • n

d t

  • t

h e v a l u e s t h e y a c q u i r e

  • r

p r

  • c

e d u r e s t h a t l a u n c h .

slide-23
SLIDE 23

Frames

  • F

r a m e s a r e " s t e r e

  • t

y p e d " k n

  • w

l e d g e u n i t s r e p r e s e n t i n g s i t u a t i

  • n

s ,

  • b

j e c t s

  • r

e v e n t s

  • r

( c l a s s e s ) s e t s

  • f

s u c h e n t i t i e s .

  • A

f r a m e i s a c

  • l

l e c t i

  • n
  • f

a t t r i b u t e s ( s l

  • t

s ) , s p e c i fj e d b y f a c e t s t h a t c

  • r

r e s p

  • n

d t

  • t

h e v a l u e s t h e y a c q u i r e

  • r

p r

  • c

e d u r e s t h a t l a u n c h .

slide-24
SLIDE 24

Frames

  • F

r a m e s a r e " s t e r e

  • t

y p e d " k n

  • w

l e d g e u n i t s r e p r e s e n t i n g s i t u a t i

  • n

s ,

  • b

j e c t s

  • r

e v e n t s

  • r

( c l a s s e s ) s e t s

  • f

s u c h e n t i t i e s .

  • A

f r a m e i s a c

  • l

l e c t i

  • n
  • f

a t t r i b u t e s ( s l

  • t

s ) , s p e c i fj e d b y f a c e t s t h a t c

  • r

r e s p

  • n

d t

  • t

h e v a l u e s t h e y a c q u i r e

  • r

p r

  • c

e d u r e s t h a t l a u n c h .

slide-25
SLIDE 25

Frames

  • F

r a m e s a r e " s t e r e

  • t

y p e d " k n

  • w

l e d g e u n i t s r e p r e s e n t i n g s i t u a t i

  • n

s ,

  • b

j e c t s

  • r

e v e n t s

  • r

( c l a s s e s ) s e t s

  • f

s u c h e n t i t i e s .

  • A

f r a m e i s a c

  • l

l e c t i

  • n
  • f

a t t r i b u t e s ( s l

  • t

s ) , s p e c i fj e d b y f a c e t s t h a t c

  • r

r e s p

  • n

d t

  • t

h e v a l u e s t h e y a c q u i r e

  • r

p r

  • c

e d u r e s t h a t l a u n c h .

slide-26
SLIDE 26

Towards semantic networks

  • R

a t h e r t h e n f

  • c

u s i n g

  • n

t h e “

  • b

j e c t ” a s p e c t , w e c

  • u

l d f

  • c

u s

  • n

t h e p r e d i c a t i

  • n

a s p e c t , j u s t a s w e d

  • w

i t h l a n g u a g e . ~

  • b

j e c t s c

  • n

s t i t u t e d b y w h a t w e c a n s a y a b

  • u

t t h e m

slide-27
SLIDE 27

“ Wi l l y t h r e w a b a l l t

  • M
  • r

g a n . ”

slide-28
SLIDE 28

“ Wi l l y t h r e w a b a l l t

  • M
  • r

g a n . ” n

  • d

e s : e n t i t i e s a r c s : r e l a t i

  • n

s h i p s

slide-29
SLIDE 29

“ Wi l l y t h r e w a b a l l t

  • M
  • r

g a n . ” n

  • d

e s : e n t i t i e s a r c s : r e l a t i

  • n

s h i p s l a b e l s

  • n

n

  • d

e s : e n t i t y n a m e s l a b e l s

  • n

a r c s : r e l a t i

  • n

n a m e s

slide-30
SLIDE 30

“ Wi l l y t h r e w a b a l l t

  • M
  • r

g a n . ”

fact( throwing, actor, willy ). % or: throwing( actor, willy ). fact( throwing, receiver, morgan ). % or: throwing( receiver, morgan ). fact( throwing, object, ball ). % or: throwing( object, ball ). who_action_what( Who, Act, What) :- fact( Act, actor, Who ), fact( Act, object, What ). ?- fact( throwing, X, willy). ?- who_action_what(willy, throwing, ball).

slide-31
SLIDE 31

“ Wi l l y t h r e w a b a l l t

  • M
  • r

g a n . ”

fact( throwing, actor, willy ). % or: throwing( actor, willy ). fact( throwing, receiver, morgan ). % or: throwing( receiver, morgan ). fact( throwing, object, ball ). % or: throwing( object, ball ). who_action_what( Who, Act, What) :- fact( Act, actor, Who ), fact( Act, object, What ). ?- fact( throwing, X, willy). ?- who_action_what(willy, throwing, ball).

We n e e d m

  • r

e k n

  • w

l e d g e t

  • i

n f e r s

  • m

e t h i n g m

  • r

e i n t e r e s t i n g !

slide-32
SLIDE 32

Semantic Networks

K n

  • w

l e d g e s y s t e m s , i n s p i r e d b y h u m a n c

  • g

n i t i

  • n

, a i m t

  • b

e r e u s a b l e a n d e ffj c i e n t . . .

slide-33
SLIDE 33

Semantic Networks

. . . b u t w h a t t h e m a c h i n e r e a d s i s n

  • t

w h a t w e r e a d !

slide-34
SLIDE 34

Semantic Networks

A n n

  • t

a t i

  • n

p r i n c i p l e : d i fg e r e n c e s i n i n t e n d e d p r

  • c

e s s i n g s h

  • u

l d b e r e fm e c t e d i n d i fg e r e n c e s i n t h e s y m b

  • l

s t r u c t u r e s

slide-35
SLIDE 35

First encounter between semantic networks and logic: KL-ONE

P r i m i t i v e c

  • n

c e p t s ( * ) d

  • n
  • t

h a v e s u ffj c i e n t c

  • n

d i t i

  • n

s , m a y h a v e n e c e s s a r y D e r i v e d c

  • n

c e p t s s p e c i fj e d b y s u ffj c i e n t a n d n e c e s s a r y c

  • n

d i t i

  • n

s .

B r a c h m a n , R . J . , & S c h m

  • l

z e , J . ( 1 9 8 5 ) . A n O v e r v i e w

  • f

t h e K L

  • O

N E K n

  • w

l e d g e R e p r e s e n t a t i

  • n

S y s t e m . C

  • g

n i t i v e S c i e n c e , 9 , 1 7 1 – 2 1 6 .

slide-36
SLIDE 36

First encounter between semantic networks and logic: KL-ONE

B r a c h m a n , R . J . , & S c h m

  • l

z e , J . ( 1 9 8 5 ) . A n O v e r v i e w

  • f

t h e K L

  • O

N E K n

  • w

l e d g e R e p r e s e n t a t i

  • n

S y s t e m . C

  • g

n i t i v e S c i e n c e , 9 , 1 7 1 – 2 1 6 . A MESSAGE is a THING with at least one Sender, all of which are PERSONs, at least one Recipient, all of which are PERSONs, exactly one Body, which is a TEXT, exactly one SendDate, which is a DATE, and exactly one ReceivedDate, which is a DATE.

v / r : v a l u e r e s t r i c t i

  • n

n / r : n u m b e r r e s t r i c t i

  • n

( m i n , m a x ) , N I L = ∞

slide-37
SLIDE 37

First encounter between semantic networks and logic: KL-ONE

B r a c h m a n , R . J . , & S c h m

  • l

z e , J . ( 1 9 8 5 ) . A n O v e r v i e w

  • f

t h e K L

  • O

N E K n

  • w

l e d g e R e p r e s e n t a t i

  • n

S y s t e m . C

  • g

n i t i v e S c i e n c e , 9 , 1 7 1 – 2 1 6 . A STARFLEET-MESSAGE is a MESSAGE, all of whose Senders are STARFLEET-COMMANDERS.

r

  • l

e r e s t r i c t i

  • n

t h r

  • u

g h v / r

slide-38
SLIDE 38

First encounter between semantic networks and logic: KL-ONE

  • K

L

  • O

N E i s a n a u t

  • m

a t i c c l a s s i fj e r

– t

a k e s a n e w C

  • n

c e p t a n d a u t

  • m

a t i c a l l y d e t e r m i n e s a l l s u b s u m p t i

  • n

r e l a t i

  • n

s ( i s

  • a

) b e t w e e n i t a n d a l l

  • t

h e r C

  • n

c e p t s i n t h e n e t w

  • r

k

– a

d d s n e w l i n k s w h e n n e w s u b s u m p t i

  • n

r e l a t i

  • n

s a r e d i s c

  • v

e r e d

– a

u t

  • m

a t e s t h e p l a c e m e n t

  • f

n e w C

  • n

c e p t s i n t h e t a x

  • n
  • m

y

– I

t i s s

  • u

n d ( a l l f

  • u

n d s u b s u m p t i

  • n

r e l a t i

  • n

s a r e l e g i t i m a t e ) b u t n

  • t

c

  • m

p l e t e ( i t d

  • e

s n

  • t

fj n d a l l s u b s u m p t i

  • n

r e l a t i

  • n

s )

  • b

a s i s f

  • r

O WL ( g i v i n g s e m a n t i c s t

  • t

h e S e m a n t i c We b )

slide-39
SLIDE 39

Differences

P r

  • l
  • g

s p e c i a l p u r p

  • s

e r e a s

  • n

i n g e n g i n e

– c

l

  • s

e d w

  • r

l d a s s u m p t i

  • n

– n

e g a t i

  • n

a s f a i l u r e ( N A F )

– o

n l y s u ffj c i e n t c

  • n

d i t i

  • n

s

– n

  • t

r u e e x i s t e n t i a l q u a n t i fj c a t i

  • n

– p

r

  • g

r a m m e r p r e v e n t s i n fj n i t e l

  • p

s K L

  • O

N E a n d O WL g e n e r a l p u r p

  • s

e k n

  • w

l e d g e m a n i p u l a t i

  • n

– o

p e n w

  • r

l d a s s u m p t i

  • n

– n

  • r

s t r

  • n

g n e g a t i

  • n

– a

t l e a s t n e c e s s a r y ,

  • p

t i

  • n

a l l y s u ffj c i e n t c

  • n

d i t i

  • n

s

– i

n fj n i t e l

  • p

s s h

  • u

l d n

  • t

b e p

  • s

s i b l e

slide-40
SLIDE 40

Qualifications of KR

slide-41
SLIDE 41

Canonicity

  • A

K R f

  • r

m a l i s m i s c a n

  • n

i c i f

  • n

e p i e c e

  • f

k n

  • w

l e d g e c a n

  • n

l y b e r e p r e s e n t e d i n

  • n

e w a y

alive(Elvis). is(Elvis, alive). alive(elvis). alive(Elvis, true). vivant(Elvis).

  • C

a n

  • n

i c i t y i s i m p r

  • v

e d b y

– r

e s t r i c t i n g t h e f

  • r

m a l i s m ( e . g .

  • n

l y u n a r y p r e d i c a t e s )

– p

r

  • v

i d i n g g u i d e l i n e s ( e . g . p r

  • p

e r n a m e i n u p p e r c a s e )

– u

s i n g s t a n d a r d v

  • c

a b u l a r i e s ( e . g . { a l i v e , d e a d } )

slide-42
SLIDE 42

Expressiveness

  • A

K R f

  • r

m a l i s m i s m

  • r

e e x p r e s s i v e t h a n a n

  • t

h e r

  • n

e i f w e c a n s a y t h i n g s i n t h e fj r s t f

  • r

m a l i s m t h a t w e c a n n

  • t

s a y i n t h e s e c

  • n

d . F i r s t O r d e r L

  • g

i c > P r

  • p
  • s

i t i

  • n

a l L

  • g

i c ∀x : m a n ( x )

m

  • r

t a l ( x ) ?

slide-43
SLIDE 43

Decidability

  • A

K R f

  • r

m a l i s m i s d e c i d a b l e , i f t h e r e i s a n a l g

  • r

i t h m t h a t c a n a n s w e r a n y q u e r y

  • n

a k n

  • w

l e d g e b a s e i n t h a t f

  • r

m a l i s m .

  • T

y p i c a l l y , t h e m

  • r

e e x p r e s s i v e a f

  • r

m a l i s m , t h e m

  • r

e l i k e l y i t i s u n d e c i d a b l e .

slide-44
SLIDE 44

Decidability

  • A

K R f

  • r

m a l i s m i s d e c i d a b l e , i f t h e r e i s a n a l g

  • r

i t h m t h a t c a n a n s w e r a n y q u e r y

  • n

a k n

  • w

l e d g e b a s e i n t h a t f

  • r

m a l i s m .

  • A

f

  • r

m a l i s m c a n b e m a d e d e c i d a b l e b y r e s t r i c t i n g i t .

– p

r

  • p
  • s

i t i

  • n

a l l

  • g

i c i s d e c i d a b l e

– F

O L i s d e c i d a b l e i f a l l f

  • r

m u l a s a r e i n t h i s f

  • r

m : ∃x , y , … . z , q , … ∀ : p ( x , y ) … = > … e x i s t e n t i a l u n i v e r s a l a r b i t r a r y f

  • r

m u l a q u a n t i fj e r s q u a n t i fj e r s w i t h

  • u

t q u a n t i fj e r s

slide-45
SLIDE 45

Closed and Open World Assumptions

  • A

K R f

  • r

m a l i s m f

  • l

l

  • w

s t h e c l

  • s

e d w

  • r

l d a s s u m p t i

  • n

( C WA ) , i f a n y s t a t e m e n t t h a t c a n n

  • t

b e p r

  • v

e n i s a s s u m e d t

  • b

e f a l s e . E x a m p l e , U F O s d

  • n
  • t

e x i s t !

I f i t i s n

  • t

t h e c a s e t h a t u f

  • s

e x i s t , t h e n i t i s t h e c a s e t h a t u f

  • s

d

  • n
  • t

e x i s t .

slide-46
SLIDE 46

Closed and Open World Assumptions

  • A

K R f

  • r

m a l i s m f

  • l

l

  • w

s t h e c l

  • s

e d w

  • r

l d a s s u m p t i

  • n

( C WA ) , i f a n y s t a t e m e n t t h a t c a n n

  • t

b e p r

  • v

e n i s a s s u m e d t

  • b

e f a l s e .

  • S
  • m

e t i m e s t h e

  • p

e n w

  • r

l d a s s u m p t i

  • n

( O WA ) i s m

  • r

e a p p r

  • p

r i a t e . A s t a t e m e n t c a n t h e n b e :

– p

r

  • v

a b l e f a l s e

– p

r

  • v

a b l e t r u e

– u

n k n

  • w

n

slide-47
SLIDE 47

Unique Name Assumption (UNA)

  • A

K R f

  • r

m a l i s m f

  • l

l

  • w

s t h e u n i q u e n a m e a s s u m p t i

  • n

( U N A ) , i f d i fg e r e n t n a m e s a l w a y s r e f e r t

  • d

i fg e r e n t

  • b

j e c t s .

slide-48
SLIDE 48

Unique Name Assumption (UNA)

  • A

K R f

  • r

m a l i s m f

  • l

l

  • w

s t h e u n i q u e n a m e a s s u m p t i

  • n

( U N A ) , i f d i fg e r e n t n a m e s a l w a y s r e f e r t

  • d

i fg e r e n t

  • b

j e c t s .

slide-49
SLIDE 49

Schemas

  • A

K R f

  • r

m a l i s m i s s c h e m a

  • b
  • u

n d , i f

  • n

e h a s t

  • d

e c i d e u p f r

  • n

t w h i c h e n t i t i e s c a n h a v e w h i c h p r

  • p

e r t i e s .

slide-50
SLIDE 50

Schemas

  • A

K R f

  • r

m a l i s m i s s c h e m a

  • b
  • u

n d , i f

  • n

e h a s t

  • d

e c i d e u p f r

  • n

t w h i c h e n t i t i e s c a n h a v e w h i c h p r

  • p

e r t i e s .

  • I

n s c h e m a

  • b
  • u

n d f

  • r

m a l i s m s ,

  • n

e h a s t

  • d

e c i d e a p r i

  • r

i f

  • r

c l a s s e s

  • f

t h i n g s a n d t h e i r p r

  • p

e r t i e s : a s c h e m a

  • b
  • u

n d f

  • r

m a l i s m p u t s m

  • r

e m

  • d

e l i n g c

  • n

s t r a i n t s , b u t c a n e x c l u d e n

  • n
  • s

e n s i b l e s t a t e m e n t s .

  • P

r

  • l
  • g

i s s c h e m a

  • f

r e e , a n y e n t i t y c a n h a v e a n y p r

  • p

e r t y .

slide-51
SLIDE 51

Schemas

  • D

a t a b a s e s a r e a p a r t i c u l a r s c h e m a

  • b
  • u

n d K R f

  • r

m a l i s m .

  • A

d a t a b a s e c a n b e s e e n a s a s e t

  • f

t a b l e s .

Name Profession Birth Elvis Singer 1935 Obama President 1961 … … … Name Resolution Brand Sony T300 4 MP Sony Ixus700 12 MP Canon … … …

e a c h r

  • w

c

  • r

r e s p

  • n

d s t

  • a

t h i n g e a c h t a b l e c

  • r

r e s p

  • n

d s t

  • n

e c l a s s

  • f

t h i n g s e a c h c

  • l

u m n c

  • r

r e s p

  • n

d s t

  • a

p r

  • p

e r t y

slide-52
SLIDE 52

Inheritance

  • A

K R f

  • r

m a l i s m s u p p

  • r

t s i n h e r i t a n c e , i f p r

  • p

e r t i e s s p e c i fj e d f

  • r
  • n

e c l a s s

  • f

t h i n g s c a n b e a u t

  • m

a t i c a l l y t r a n s f e r r e d t

  • a

m

  • r

e s p e c i fj c c l a s s .

  • A

c l a s s i s a s e t

  • f

e n t i t i e s w i t h t h e s a m e p r

  • p

e r t i e s .

P e r s

  • n

Name Profession Birth S i n g e r Name Profession Birth Instrument m

  • r

e g e n e r a l c l a s s , f e w p r

  • p

e r t i e s m

  • r

e s p e c i fj c c l a s s , m

  • r

e p r

  • p

e r t i e s , s

  • m

e r e s t r i c t i

  • n

s : = s i n g e r i n h e r i t e d p r

  • p

e r t i e s a d d i t i

  • n

a l p r

  • p

e r t i e s r e s t r i c t i

  • n

i n h e r i t a n c e / s u b c l a s s r e l a t i

  • n

s h i p

slide-53
SLIDE 53

Monotonicity and non-monotonicity

  • A

K R f

  • r

m a l i s m i s m

  • n
  • t
  • n

i c , i f a d d i n g n e w k n

  • w

l e d g e d

  • e

s n

  • t

u n d

  • d

e d u c e d f a c t s .

slide-54
SLIDE 54

Monotonicity and non-monotonicity

  • A

K R f

  • r

m a l i s m i s m

  • n
  • t
  • n

i c , i f a d d i n g n e w k n

  • w

l e d g e d

  • e

s n

  • t

u n d

  • d

e d u c e d f a c t s .

  • F

i r s t

  • r

d e r l

  • g

i c a n d p r

  • p
  • s

i t i

  • n

a l l

  • g

i c a r e m

  • n
  • t
  • n

i c .

  • M
  • n
  • t
  • n

i c i t y c a n b e c

  • u

n t e r

  • i

n t u i t i v e . I t r e q u i r e s t

  • k

n

  • w

e v e r y t h i n g u p

  • f

r

  • n

t .

elvis_is_person elvis_is_alive elvis_is_dead => ~ elvis_is_alive

+

=> elvis_is_alive elvis_is_person elvis_is_alive elvis_is_dead => ~ elvis_is_alive elvis_is_dead => michael_jackson_alive => elvis_is_dead

⊆ ⊆

=> elvis_is_alive

s u b s e t

slide-55
SLIDE 55
  • A

K R f

  • r

m a l i s m i s m

  • n
  • t
  • n

i c , i f a d d i n g n e w k n

  • w

l e d g e d

  • e

s n

  • t

u n d

  • d

e d u c e d f a c t s .

  • D

e f a u l t l

  • g

i c i s n

  • t

m

  • n
  • t
  • n

i c .

elvis_is_person: elvis_is_alive elvis_is_alive => elvis_is_alive elvis_is_dead ~elvis_is_alive if Elvis is a person (and nothing says he’s not alive) then he is alive if Elvis is dead then he is not alive elvis_is_person elvis_is_dead

+

prerequisite conclusion justification

Monotonicity and non-monotonicity

slide-56
SLIDE 56
  • A

K R f

  • r

m a l i s m i s d i s t r i b u t e d , i f i t e n c

  • u

r a g e s u s e a n d c

  • p

e r a t i

  • n

– b

y d i fg e r e n t p e

  • p

l e

– b

y d i fg e r e n t s y s t e m s

– a

c r

  • s

s d i fg e r e n t p l a c e s

– a

c r

  • s

s d i fg e r e n t

  • r

g a n i z a t i

  • n

s .

Distributedness

slide-57
SLIDE 57

Semantic Web

slide-58
SLIDE 58

What's in a web page?

  • T

e x t u a l c

  • n

t e n t , m a r k u p a n d e m b e d d e d m e d i a

  • T

h e t y p i c a l m a r k u p c

  • n

s i s t s

  • f

:

– h

y p e r

  • l

i n k s t

  • r

e l a t e d c

  • n

t e n t ,

– r

e n d e r i n g i n f

  • r

m a t i

  • n

( p a g i n a t i

  • n

, f

  • n

t s i z e a n d c

  • l
  • u

r , … )

  • T

h e s e m a n t i c c

  • n

t e n t i s a c c e s s i b l e t

  • h

u m a n s b u t n

  • t

d i r e c t l y t

  • c
  • m

p u t e r s . . .

slide-59
SLIDE 59

The Web was designed as an information space, with the goal that it

should be useful not only for human-human communication, but also that machines would be able to participate and help.

One of the major obstacles to this has been the fact that most information on the Web is designed for human consumption, and even if it was derived from a database with well

defined meanings (in at least some terms) for its columns, that the structure of the data is not evident to a robot browsing the Web. Leaving aside the artificial intelligence problem of training machines to behave like people, the Semantic Web approach instead develops

languages for expressing information in a machine processable form.

T i m B e r n e r s

  • L

e e , T h e S e m a n t i c We b R

  • a

d m a p .

slide-60
SLIDE 60
  • E

x t e r n a l a g r e e m e n t

  • n

m e a n i n g

  • f

a n n

  • t

a t i

  • n

s

– P

r

  • b

l e m s w i t h t h i s a p p r

  • a

c h

  • I

n fm e x i b l e

  • L

i m i t e d n u m b e r

  • f

t h i n g s c a n b e e x p r e s s e d

How to add meaning for machines?

slide-61
SLIDE 61
  • E

x t e r n a l a g r e e m e n t

  • n

m e a n i n g

  • f

a n n

  • t

a t i

  • n

s

– P

r

  • b

l e m s w i t h t h i s a p p r

  • a

c h

  • I

n fm e x i b l e

  • L

i m i t e d n u m b e r

  • f

t h i n g s c a n b e e x p r e s s e d

  • U

s e f

  • r

m a l v

  • c

a b u l a r i e s

  • r
  • n

t

  • l
  • g

i e s t

  • s

p e c i f y m e a n i n g

  • f

a n n

  • t

a t i

  • n

s

– o

n t

  • l
  • g

i e s p r

  • v

i d e a v

  • c

a b u l a r y

  • f

t e r m s t h a t a r e m a c h i n e u n d e r s t a n d a b l e

– n

e w t e r m s c a n b e f

  • r

m e d b y c

  • m

b i n i n g e x i s t i n g

  • n

e s a s a k i n d

  • f

“ c

  • n

c e p t u a l L e g

– m

e a n i n g ( s e m a n t i c s )

  • f

s u c h t e r m s i s f

  • r

m a l l y s p e c i fj e d

How to add meaning for machines?

slide-62
SLIDE 62

Four principles towards a Semantic Web of Data

  • P

1 : g i v e a l l t h i n g s a n a m e

slide-63
SLIDE 63

Four principles towards a Semantic Web of Data

  • P

2 : r e l a t i

  • n

s h i p s f

  • r

m a g r a p h b e t w e e n t h i n g s ( a k n

  • w

l e d g e g r a p h )

slide-64
SLIDE 64

Four principles towards a Semantic Web of Data

  • P

3 : n a m e s a r e a d d r e s s e s

  • n

t h e We b

slide-65
SLIDE 65
  • P

1 + P 2 + P 3 : a h u g e g l

  • b

a l g r a p h

L i n k i n g

  • p

e n d a t a c l

  • u

d d i a g r a m : h t t p : / / l

  • d
  • c

l

  • u

d . n e t /

slide-66
SLIDE 66

Four principles towards a Semantic Web of Data

  • P

4 : g i v e e x p l i c i t , f

  • r

m a l s e m a n t i c s

– a

s s i g n t y p e s t

  • t

h i n g s

– a

s s i g n t y p e s t

  • r

e l a t i

  • n

s

– o

r g a n i z e t y p e s i n h i e r a r c h i e s

– s

p e c i f y c

  • n

s t r a i n t s

slide-67
SLIDE 67

Semantic Web

  • T

h e S e m a n t i c We b i s a n e v

  • l

v i n g e x t e n s i

  • n
  • f

t h e Wo r l d Wi d e We b , p r

  • m
  • t

i n g a d i s t r i b u t e d k n

  • w

l e d g e r e p r e s e n t a t i

  • n

.

  • I

t p r

  • v

i d e s s t a n d a r d s t

  • – i

d e n t i f y e n t i t i e s ( U R I s )

– e

x p r e s s f a c t s ( R D F )

– e

x p r e s s c

  • n

c e p t s ( R D F S )

– s

h a r e v

  • c

a b u l a r i e s

– r

e a s

  • n
  • n

f a c t s ( O WL )

  • T

h e s e s t a n d a r d s a r e p r

  • d

u c e d a n d e n d

  • r

s e d b y t h e Wo r d Wi d e We b C

  • n

s

  • r

t i u m ( W3 C )

slide-68
SLIDE 68

The Semantic Web Tower

slide-69
SLIDE 69

URI and namespaces

  • U

R I = u n i f

  • r

m r e s

  • u

r c e s i d e n t i fj e r

– u

n i f

  • r

m r e s

  • u

r c e n a m e s ( U R N s ) : U R I s u s e d t

  • n

a m e s

  • m

e t h i n g , e v e n i f t h i s i s a n a b s t r a c t

  • b

j e c t t h a t i s n

  • t

a v a i l a b l e

  • n

t h e We b .

  • f
  • r

i n s t a n c e , a p e r s

  • n

m i g h t h a v e a U R I t h a t i s u s e d i n

  • n

t

  • l
  • g

i e s t

  • r

e f e r t

  • t

h a t p e r s

  • n

.

– u

n i f

  • r

m r e s

  • u

r c e l

  • c

a t

  • r

s ( U R L s ) : U R I s u s e d t

  • s

p e c i f y t h e l

  • c

a t i

  • n
  • f

s

  • m

e t h i n g . t h e y s t a r t w i t h a p r

  • t
  • c
  • l

i d e n t i fj e r , w i t h a w e l l

  • e

s t a b l i s h e d t e c h n i c a l i n t e r p r e t a t i

  • n

( e . g . " h t t p " ) .

slide-70
SLIDE 70

URI and namespaces

  • N

a m e s p a c e s

– D

e r i v e d f r

  • m

d

  • m

a i n r e g i s t r a t i

  • n

( e . g . e p i t a . f r )

– E

v e r y t h i n g u p t

  • #

m a y b e n a m e s p a c e

  • E

x a m p l e s : u r n : m y a p p n a m e : s t u d e n t s # s t u d e n t 1 2 3 4 h t t p : / / m y s e r v e r . c

  • m

/ m y a p p / s t u d e n t s / s t u d e n t 1 2 3 4

slide-71
SLIDE 71

URI and namespaces

  • N

a m e s p a c e s

– D

e r i v e d f r

  • m

d

  • m

a i n r e g i s t r a t i

  • n

( e . g . e p i t a . f r )

– E

v e r y t h i n g u p t

  • #

m a y b e n a m e s p a c e

  • E

x a m p l e s : u r n : m y a p p n a m e : s t u d e n t s # s t u d e n t 1 2 3 4 h t t p : / / m y s e r v e r . c

  • m

/ m y a p p / s t u d e n t s / s t u d e n t 1 2 3 4

  • U

R I a r e d e r e f e r e n c i a b l e i f t h e r e s

  • u

r c e i d e n t i fj e d b y t h e U R I i s r e t r i e v a b l e f r

  • m

t h a t U R I

slide-72
SLIDE 72

RDF (resource description framework)

  • R

D F i s a d a t a m

  • d

e l :

– a

p p l i c a t i

  • n

a n d d

  • m

a i n i n d e p e n d e n t

– b

a s e d

  • n

s i m p l e t r i p l e f

  • r

m a t

– (

l a b e l e d a n d d i r e c t e d ) g r a p h

slide-73
SLIDE 73

RDF (resource description framework)

  • R

D F i s a d a t a m

  • d

e l :

– a

p p l i c a t i

  • n

a n d d

  • m

a i n i n d e p e n d e n t

– b

a s e d

  • n

s i m p l e t r i p l e f

  • r

m a t

– (

l a b e l e d a n d d i r e c t e d ) g r a p h

  • R

D F “ s t a t e m e n t s ” c

  • n

s i s t

  • f

– r

e s

  • u

r c e s ( = n

  • d

e s )

  • w

h i c h h a v e p r

  • p

e r t i e s

– w

h i c h h a v e v a l u e s ( = n

  • d

e s , s t r i n g s , . . . )

slide-74
SLIDE 74

RDF (resource description framework)

  • R

D F i s a d a t a m

  • d

e l :

– a

p p l i c a t i

  • n

a n d d

  • m

a i n i n d e p e n d e n t

– b

a s e d

  • n

s i m p l e t r i p l e f

  • r

m a t

– (

l a b e l e d a n d d i r e c t e d ) g r a p h

  • R

D F “ s t a t e m e n t s ” c

  • n

s i s t

  • f

– r

e s

  • u

r c e s ( = n

  • d

e s )

  • w

h i c h h a v e p r

  • p

e r t i e s

– w

h i c h h a v e v a l u e s ( = n

  • d

e s , s t r i n g s ) p r e d i c a t e ( s u b j e c t ,

  • b

j e c t ) s u b j e c t p r e d i c a t e

  • b

j e c t

slide-75
SLIDE 75

RDF (resource description framework)

slide-76
SLIDE 76

RDF and XML

  • B

e i n g s

  • g

e n e r a l , s y n t a c t i c d e t a i l s a r e r e l a t i v e l y i n s i g n i fj c a n t ; h

  • w

e v e r X M L i s a n e x a m p l e

  • f

c

  • m

m

  • n

l y u s e d s y n t a c t i c s t r u c t u r e .

– N

O T E : X M L i s j u s t a w a y t

  • w

r i t e a n d t r a n s p

  • r

t R D F , b u t i s n

  • t

a c

  • m

p

  • n

e n t

  • f

R D F ! R D F d a t a c a n a l s

  • b

e s t

  • r

e d v e r y d i fg e r e n t l y , f

  • r

e x a m p l e i n a r e l a t i

  • n

a l d a t a b a s e

.

slide-77
SLIDE 77

RDF, a note on resources

  • A

g r a p h n

  • d

e ( c

  • r

r e s p

  • n

d i n g t

  • a

r e s

  • u

r c e ) c a n b e

– t

h e v a l u e

  • f

a p r

  • p

e r t y

– a

r b i t r a r i l y c

  • m

p l e x t r e e a n d g r a p h s t r u c t u r e s

  • S

y n t a c t i c a l l y , v a l u e s c a n b e

– e

m b e d d e d ( i . e . l e x i c a l l y i n

  • l

i n e )

– o

r r e f e r e n c e d ( l i n k e d )

slide-78
SLIDE 78

RDF Schema

  • B

a s e

  • l

e v e l s p e c i fj c a t i

  • n
  • f

s e m a n t i c s

slide-79
SLIDE 79

RDF Schema

  • B

a s e

  • l

e v e l s p e c i fj c a t i

  • n
  • f

s e m a n t i c s

  • L

a n g u a g e c

  • n

s t r u c t s i n c l u d e :

– c

l a s s ,

– p

r

  • p

e r t y ,

– s

u b c l a s s ,

– s

u b p r

  • p

e r t y

  • C

l a s s e s a n d p r

  • p

e r t i e s a r e t h e m s e l v e s a l s

  • r

e s

  • u

r c e s : t h i s e n a b l e s a n n

  • t

a t i

  • n

s a b

  • u

t a n n

  • t

a t i

  • n

s

  • V
  • c

a b u l a r y c a n b e u s e d t

  • d

e fj n e

  • t

h e r v

  • c

a b u l a r i e s f

  • r

y

  • u

r a p p l i c a t i

  • n

d

  • m

a i n

slide-80
SLIDE 80

RDF(S) Terminology and Semantics

  • C

l a s s e s a n d c l a s s h i e r a r c h y

– A

l l c l a s s e s a r e i n s t a n c e s

  • f

r d f s : C l a s s

– A

c l a s s h i e r a r c h y i s d e fj n e d b y r d f s : s u b C l a s s O f

  • I

n s t a n c e s ( i n d i v i d u a l s )

  • f

a c l a s s

– d

e fj n e d b y r d f : t y p e

slide-81
SLIDE 81

RDF(S) Terminology and Semantics

  • P

r

  • p

e r t i e s

– p

r

  • p

e r t i e s a r e g l

  • b

a l : a p r

  • p

e r t y n a m e i n

  • n

e p l a c e i s t h e s a m e a s t h e p r

  • p

e r t y n a m e i n a n

  • t

h e r ( a s s u m i n g t h e s a m e n a m e s p a c e )

– p

r

  • p

e r t i e s f

  • r

m a h i e r a r c h y , r d f s : s u b P r

  • p

e r t y O f

  • D
  • m

a i n a n d R a n g e

  • f

a p r

  • p

e r t y

– d

  • m

a i n : t h e c l a s s (

  • r

c l a s s e s ) t h a t h a v e t h e p r

  • p

e r t y

– r

a n g e : t h e c l a s s (

  • r

c l a s s e s ) t

  • w

h i c h p r

  • p

e r t y v a l u e s b e l

  • n

g

slide-82
SLIDE 82

RDF(S) Terminology and Semantics

slide-83
SLIDE 83

RDF(S) Terminology and Semantics

E x a m p l e :

(ex:MotorVehicle, rdf:type, rdfs:Class) (ex:PassengerVehicle, rdf:type, rdfs:Class) (ex:Van, rdf:type, rdfs:Class) (ex:Truck, rdf:type, rdfs:Class) (ex:MiniVan, rdf:type, rdfs:Class) (ex:PassengerVehicle, rdfs:subClassOf, ex:MotorVehicle) (ex:Van, rdfs:subClassOf, ex:MotorVehicle) (ex:Truck, rdfs:subClassOf, ex:MotorVehicle) (ex:MiniVan, rdfs:subClassOf, ex:Van) (ex:MiniVan, rdfs:subClassOf, ex:PassengerVehicle)

slide-84
SLIDE 84

Querying RDF: SPARQL

  • S

i m p l e P r

  • t
  • c
  • l

A n d R D F Q u e r y L a n g u a g e

– W3

C s t a n d a r d i s a t i

  • n

e fg

  • r

t s i m i l a r t

  • t

h e X q u e r y q u e r y l a n g u a g e f

  • r

X M L d a t a

– s

u i t a b l e f

  • r

r e m

  • t

e u s e ( r e m

  • t

e a c c e s s p r

  • t
  • c
  • l

)

PREFIX abc: <http://mynamespace.com/exampleOntology#> SELECT ?capital ?country WHERE { ?x abc:cityname ?capital. ?y abc:countryname ?country. ?x abc:isCapitalOf ?y. ?y abc:isInContinent abc:africa. }

slide-85
SLIDE 85

OWL (Web Ontology Language)

  • O

WL a d d s e x p r e s s i v i t y t

  • R

D F S c h e m a t

  • e

n a b l e m

  • r

e p

  • w

e r f u l s e m a n t i c s :

c a r d i n a l i t y r e s t r i c t i

  • n

s ,

l

  • c

a l r a n g e c

  • n

s t r a i n t s ,

e q u a l i t y

  • f

r e s

  • u

r c e s ,

i n v e r s e , s y m m e t r i c a n d t r a n s i t i v e p r

  • p

e r t i e s ,

b

  • l

e a n c l a s s c

  • m

b i n a t i

  • n

s ,

d i s j

  • i

n t n e s s a n d c

  • m

p l e t e n e s s , …

slide-86
SLIDE 86

OWL (Web Ontology Language)

  • O

WL a d d s e x p r e s s i v i t y t

  • R

D F S c h e m a t

  • e

n a b l e m

  • r

e p

  • w

e r f u l s e m a n t i c s :

c a r d i n a l i t y r e s t r i c t i

  • n

s ,

l

  • c

a l r a n g e c

  • n

s t r a i n t s ,

e q u a l i t y

  • f

r e s

  • u

r c e s ,

i n v e r s e , s y m m e t r i c a n d t r a n s i t i v e p r

  • p

e r t i e s ,

b

  • l

e a n c l a s s c

  • m

b i n a t i

  • n

s ,

d i s j

  • i

n t n e s s a n d c

  • m

p l e t e n e s s , …

  • O

WL L i t e : s u b s e t

  • f

f e a t u r e s t h a t i s e a s y t

  • i

m p l e m e n t a n d u s e

  • O

WL D L : s u b s e t

  • f

f e a t u r e s s u p p

  • r

t i n g d e s c r i p t i

  • n
  • l
  • g

i c r e a s

  • n

i n g ( e . g . u s e f u l f

  • r
  • n

t

  • l
  • g

y c

  • n

s t r u c t i

  • n

)

slide-87
SLIDE 87

Instances, Taxonomies, Mereonomies

hierarchies compositions

  • bjects
slide-88
SLIDE 88

Individuals (IS-INSTANCE-OF)

  • T

h e c

  • n

c e p t

  • f

c l a s s i n t u i t i v e l y r e f e r s t

  • s
  • m

e e n t i t y t h a t b e l

  • n

g s t

  • t

h a t c l a s s .

  • T

h i s e n t i t y

  • r
  • b

j e c t i s s a i d t

  • a

n i n s t a n c e

  • f

t h a t c l a s s .

slide-89
SLIDE 89

Individuals (IS-INSTANCE-OF)

class Person { String name void setName(String newName) { name = newName } } p = new Person() p.setName("Plato")

slide-90
SLIDE 90

Individuals (IS-INSTANCE-OF)

class Person { String name void setName(String newName) { name = newName } } p = new Person() p.setName("Plato")

d e s c r i b e p r

  • p

e r t i e s

  • f

t h e s y s t e m

slide-91
SLIDE 91

Individuals (IS-INSTANCE-OF)

class Person { String name void setName(String newName) { name = newName } } p = new Person() p.setName("Plato")

a c t u a l l y a l l

  • c

a t e ( m e m

  • r

y ) s p a c e f

  • r

t h e

  • b

j e c t

slide-92
SLIDE 92

Individuals (IS-INSTANCE-OF)

class Person { String name void setName(String newName) { name = newName } } p = new Person() p.setName("Plato")

a p p l y t h e r e q u i r e d m e t h

  • d

t

  • t

h e

  • b

j e c t

slide-93
SLIDE 93

Hierarchy as Taxonomy (IS-A)

  • T

h i n g s a n d c

  • n

c e p t s a r e u s u a l l y h i e r a r c h i c a l l y c l a s s i fj e d b

  • t

h i n c

  • m

m

  • n

a n d e x p e r t k n

  • w

l e d g e .

slide-94
SLIDE 94

Hierarchy as Taxonomy (IS-A)

  • T

h i n g s a n d c

  • n

c e p t s a r e u s u a l l y h i e r a r c h i c a l l y c l a s s i fj e d b

  • t

h i n c

  • m

m

  • n

a n d e x p e r t k n

  • w

l e d g e .

  • G

i v e n a c e r t a n c l a s s , a s u b c l a s s

  • r

d e r i v e d c l a s s i n h e r i t s c e r t a i n p r

  • p

e r t i e s ( a s a t t r i b u t e s a n d m e t h

  • d

s ) f r

  • m

t h e fj r s t .

– F

r

  • m

t h e p e r s p e c t i v e

  • f

t h e s e c

  • n

d c l a s s , t h e fj r s t i s c a l l e d s u p e r c l a s s .

– U

s u a l l y , d e r i v a t i

  • n

m i g h t b e

  • v

e r r i d d e n .

slide-95
SLIDE 95

Hierarchy as Taxonomy (IS-A)

class A { String salutation = "Ciao" void show() { print(salutation + "! My type is A.") } } class B extends A { @Override void show() { print(salutation + "! My type is B.") } }

  • = new A()
  • .show()
  • = new B()
  • .show()

C i a

  • !

My t y p e i s A . C i a

  • !

My t y p e i s B .

  • utput
slide-96
SLIDE 96

Hierarchy as partonomy (HAS-A)

  • G

i v e n a n

  • b

j e c t

  • f

a c e r t a i n c l a s s , i f i t i s c

  • m

p

  • s

e d b y

  • t

h e r

  • b

j e c t s , t h e s e c

  • n

d

  • n

e s b e l

  • n

g t

  • t

h e fj r s t .

slide-97
SLIDE 97

Hierarchy as partonomy (HAS-A)

  • G

i v e n a n

  • b

j e c t

  • f

a c e r t a i n c l a s s , i f i t i s c

  • m

p

  • s

e d b y

  • t

h e r

  • b

j e c t s , t h e s e c

  • n

d

  • n

e s b e l

  • n

g t

  • t

h e fj r s t .

– T

h e c a r h a s f

  • u

r w h e e l s .

– T

h

  • s

e w h e e l s b e l

  • n

g s t

  • t

h e c a r .

slide-98
SLIDE 98

Hierarchy as partonomy (HAS-A)

  • G

i v e n a n

  • b

j e c t

  • f

a c e r t a i n c l a s s , i f i t i s c

  • m

p

  • s

e d b y

  • t

h e r

  • b

j e c t s , t h e s e c

  • n

d

  • n

e s b e l

  • n

g t

  • t

h e fj r s t .

– T

h e c a r h a s f

  • u

r w h e e l s .

– T

h

  • s

e w h e e l s b e l

  • n

g s t

  • t

h e c a r . . . . b u t t h i n g s a r e a b i t m

  • r

e c

  • m

p l i c a t e d !

slide-99
SLIDE 99

“Strict” composition

class Car { Wheel frontLeftWheel Wheel frontRightWheel Wheel rearLeftWheel Wheel rearRightWheel Car { frontLeftWheel = new Wheel() frontRightWheel = new Wheel() rearLeftWheel = new Wheel() rearRightWheel = new Wheel() } } car = new Car()

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SLIDE 100

class Car { Wheel frontLeftWheel Wheel frontRightWheel Wheel rearLeftWheel Wheel rearRightWheel Car { } void mountWheels(fLW, fRW, rLW, rRW) { frontLeftWheel = fLW frontRightWheel = fRW rearLeftWheel = rLW rearLeftWheel = rRW } } car = new Car() car.mountWheels(...)

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Aggregation or weak composition

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SLIDE 101

Example of ontology in description logic

Woman Person Female ≐ ⊓ Man Person ¬Female ≐ ⊓ Mother Woman hasChild.Person ≐ ⊓ ∃ Father Man hasChild.Person ≐ ⊓ ∃ Parent Person hasChild.Person ≐ ⊓ ∃ Grandmother Mother hasChild.Parent ≐ ⊓ ∃ DaughterlessMother Mother hasChild.¬Female ≐ ⊓ ∀

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SLIDE 102

Example of ontology in description logic

Woman Person Female ≐ ⊓ Man Person ¬Female ≐ ⊓ Mother Woman hasChild.Person ≐ ⊓ ∃ Father Man hasChild.Person ≐ ⊓ ∃ Parent Person hasChild.Person ≐ ⊓ ∃ Grandmother Mother hasChild.Parent ≐ ⊓ ∃ DaughterlessMother Mother hasChild.¬Female ≐ ⊓ ∀ DaughterlessMother(Paulette) Child(Paulette, Pierre) Child(Paulette, Jacques) Father(Pierre) Child(Pierre, Marinette)

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