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Page 1: Whu beamer

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ÉÇ�Æ êÆ�ÚOÆ�

November 14, 2007

Page 2: Whu beamer

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1 �o´o÷8

2 o÷8A^Þ~

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4 C°Ýo÷8

5 �z

Page 3: Whu beamer

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What is Rough Set?

A�ÎÒ:

U k��, U ={x1, x2, . . . , xn

}.

R �d'X(÷vg�!é¡ÚD45).

[x]R �da, [x]R ={y ∈ U

∣∣ (x, y) ∈ R}.

U/R �d'X R y©Ø� U , ¤��da�8Ü.

¯K:

Question

�½ X ⊆ U , XÛ^�da

[xi1 ]R , [xi2 ]R , · · · , [xik ]R

£ãL� X?

Page 4: Whu beamer

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What is Rough Set?

A�ÎÒ:

U k��, U ={x1, x2, . . . , xn

}.

R �d'X(÷vg�!é¡ÚD45).

[x]R �da, [x]R ={y ∈ U

∣∣ (x, y) ∈ R}.

U/R �d'X R y©Ø� U , ¤��da�8Ü.

¯K:

Question

�½ X ⊆ U , XÛ^�da

[xi1 ]R , [xi2 ]R , · · · , [xik ]R

£ãL� X?

Page 5: Whu beamer

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What is Rough Set?

�½Ø� U ;^���d'Xò U ?1y©;�½8I8Ü X;X �eCq RX =

{x ∈ U

∣∣ [x]R ⊆ X}.

X �>.�.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 6: Whu beamer

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What is Rough Set?

�½Ø� U ;^���d'Xò U ?1y©;�½8I8Ü X;X �eCq RX =

{x ∈ U

∣∣ [x]R ⊆ X}.

X �>.�.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 7: Whu beamer

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What is Rough Set?

�½Ø� U ;^���d'Xò U ?1y©;�½8I8Ü X;X �eCq RX =

{x ∈ U

∣∣ [x]R ⊆ X}.

X �>.�.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 8: Whu beamer

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What is Rough Set?

�½Ø� U ;^���d'Xò U ?1y©;�½8I8Ü X;X �eCq RX =

{x ∈ U

∣∣ [x]R ⊆ X}.

X �>.�.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 9: Whu beamer

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What is Rough Set?

�½Ø� U ;^���d'Xò U ?1y©;�½8I8Ü X;X �eCq RX =

{x ∈ U

∣∣ [x]R ⊆ X}.

X �>.�.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 10: Whu beamer

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�½ X ⊆ U , �^ U/R ¥���5£ã!L� X, Ø�½U°(/?1©�~~�±^'u X ��éeCq!þCq5.½ X, ù��o÷8Vg��)©

½Â (Pawlak(1982)[2])

� R ´Ø� U þ��d'X, é8Ü X ⊆ U , óé

(RX, RX

)¡� X 3Cq�m (U,R) þ���o÷C

q, Ù¥

RX ={x ∈ U

∣∣ [x]R ⊆ X}

,

RX ={x ∈ U

∣∣ [x]R ∩X 6= ∅}

.(1)

RX!RX ©O¡� X � R eCqÚ R þCq©

Page 11: Whu beamer

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o÷8�½Â

�½ X ⊆ U , �^ U/R ¥���5£ã!L� X, Ø�½U°(/?1©�~~�±^'u X ��éeCq!þCq5.½ X, ù��o÷8Vg��)©

½Â (Pawlak(1982)[2])

� R ´Ø� U þ��d'X, é8Ü X ⊆ U , óé

(RX, RX

)¡� X 3Cq�m (U,R) þ���o÷C

q, Ù¥

RX ={x ∈ U

∣∣ [x]R ⊆ X}

,

RX ={x ∈ U

∣∣ [x]R ∩X 6= ∅}

.(1)

RX!RX ©O¡� X � R eCqÚ R þCq©

Page 12: Whu beamer

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��ûüL�~f

(a) ��&EûüL

Ø� ^ � á 5 ûüá5

¾< ÞÛ *SÛ N§ 6a

e1 ´ ´ �~ Ä

e2 ´ ´ p ´

e3 ´ ´ ép ´

e4 Ä ´ �~ Ä

e5 Ä Ä p Ä

e6 Ä ´ ép ´

e7 Ä Ä p ´

e8 Ä ´ ép Ä

(b) êizL��ûüL

U C D

a b c d

1 1 1 1 0

2 1 1 2 1

3 1 1 3 1

4 0 1 1 0

5 0 0 2 0

6 0 1 3 1

7 0 0 2 1

8 0 1 3 0

Page 13: Whu beamer

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��ûüL�~f

(a) ��&EûüL

Ø� ^ � á 5 ûüá5

¾< ÞÛ *SÛ N§ 6a

e1 ´ ´ �~ Ä

e2 ´ ´ p ´

e3 ´ ´ ép ´

e4 Ä ´ �~ Ä

e5 Ä Ä p Ä

e6 Ä ´ ép ´

e7 Ä Ä p ´

e8 Ä ´ ép Ä

(b) êizL��ûüL

U C D

a b c d

1 1 1 1 0

2 1 1 2 1

3 1 1 3 1

4 0 1 1 0

5 0 0 2 0

6 0 1 3 1

7 0 0 2 1

8 0 1 3 0

Page 14: Whu beamer

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ûüL^�á5�«©Ý

ûüL�«©ÝXeL¤«(dué¡5��ÑÙen�Ü©).

1 2 3 4 5 6 7 812 c3 c c4 a a, c a5 a, b, c a, b a, b, c b, c6 a, c a, c a, c c b, c7 a, b, c a, b a, b, c b, c b, c8 a, c a, c a, c c b, c b, c

N´��^�á5�{� {a, c}.

Page 15: Whu beamer

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^�á5��{

ÏLá5�{, ûüL{z�Xe�/ª:

LLL: �{�ûüL

U C Da c d

1 1 1 02 1 2 13 1 3 14 0 1 05 0 2 06 0 3 17 0 2 18 0 3 0

dL�, D/{d} ={{1, 4, 5, 8}, {2, 3, 6, 7}

};

U/{a, c} ={{1}, {2}, {3}, {4}, {5, 7}, {6, 8}

}.

Page 16: Whu beamer

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ûü5K

P D0 = {1, 4, 5, 8}, D1 = {2, 3, 6, 7}, K RD0 = {1, 4},RD1 = {2, 3}. ? ��(½�ûü5K:

r1 : (a, 1) ∧ (c, 1) 7−→ (d, 0); (2)r2 : (a, 0) ∧ (c, 1) 7−→ (d, 0); (3)r3 : (a, 1) ∧ (c, 3) 7−→ (d, 1); (4)r4 : (a, 1) ∧ (c, 2) 7−→ (d, 1). (5)

ù�ÒlÃS,�&E¥���<�Jøë��ûü5K:

(ÞÛ, ´)�(N§, �~) 7−→ (6a, Ä); (6)(ÞÛ, Ä)�(N§, �~) 7−→ (6a, Ä); (7)(ÞÛ, ´)�(N§, ép) 7−→ (6a, ´); (8)

(ÞÛ, ´)�(N§, p) 7−→ (6a, ´). (9)

Page 17: Whu beamer

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ûü5K

P D0 = {1, 4, 5, 8}, D1 = {2, 3, 6, 7}, K RD0 = {1, 4},RD1 = {2, 3}. ? ��(½�ûü5K:

r1 : (a, 1) ∧ (c, 1) 7−→ (d, 0); (2)r2 : (a, 0) ∧ (c, 1) 7−→ (d, 0); (3)r3 : (a, 1) ∧ (c, 3) 7−→ (d, 1); (4)r4 : (a, 1) ∧ (c, 2) 7−→ (d, 1). (5)

ù�ÒlÃS,�&E¥���<�Jøë��ûü5K:

(ÞÛ, ´)�(N§, �~) 7−→ (6a, Ä); (6)(ÞÛ, Ä)�(N§, �~) 7−→ (6a, Ä); (7)(ÞÛ, ´)�(N§, ép) 7−→ (6a, ´); (8)

(ÞÛ, ´)�(N§, p) 7−→ (6a, ´). (9)

Page 18: Whu beamer

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A^^�

o÷8^�:ROSE2(Rough Sets Data Explorer: http://idss.cs.put.poznan.pl);

RSES2(Rough Set Exploration System: http://logic.mimuw.edu.pl);

RS-SYSTEMS(http://www.rs-systems.com/).

Page 19: Whu beamer

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C°Ý�{{0

ù´²;o÷8ã«;ã¥�Ú¬�¹k�þ�k^&E, C°Ý�g�Ò´N�8Ü��¹§Ý, l ¦TÚ¬�B\�eCq8;b�©a�(Ç β = 0.8, Kã¥�Ú¬ÑB\�eCq8.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 20: Whu beamer

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C°Ý�{{0

ù´²;o÷8ã«;ã¥�Ú¬�¹k�þ�k^&E, C°Ý�g�Ò´N�8Ü��¹§Ý, l ¦TÚ¬�B\�eCq8;b�©a�(Ç β = 0.8, Kã¥�Ú¬ÑB\�eCq8.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 21: Whu beamer

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C°Ý�{{0

ù´²;o÷8ã«;ã¥�Ú¬�¹k�þ�k^&E, C°Ý�g�Ò´N�8Ü��¹§Ý, l ¦TÚ¬�B\�eCq8;b�©a�(Ç β = 0.8, Kã¥�Ú¬ÑB\�eCq8.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 22: Whu beamer

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C°Ýo÷8½Â

½Â (Ziarko (1993)[3])

� X ´k�Ø� U ���f8. é β ∈ (0.5, 1], ½Â X� β–eCq!β–þCq©O�

Rβ(X) =⋃ {

Xi ∈ U/R∣∣∣ Xi

β⊆X

}, (10)

Rβ(X) =⋃ {

Xi ∈ U/R∣∣∣ Xi

1−β⊂ X

}. (11)

Page 23: Whu beamer

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β–þCq8ã«

β–þCq: Rβ(X) =⋃ {

Xi ∈ U/R∣∣∣ Xi

1−β⊂ X

}.

b½ 1− β = 0.2, Kã¥�Ú¬Ø2áuþCq8.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 24: Whu beamer

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β–þCq8ã«

β–þCq: Rβ(X) =⋃ {

Xi ∈ U/R∣∣∣ Xi

1−β⊂ X

}.

b½ 1− β = 0.2, Kã¥�Ú¬Ø2áuþCq8.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 25: Whu beamer

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β–þCq8ã«

β–þCq: Rβ(X) =⋃ {

Xi ∈ U/R∣∣∣ Xi

1−β⊂ X

}.

b½ 1− β = 0.2, Kã¥�Ú¬Ø2áuþCq8.

8Ü X �>.

X �eCq(��)

X �þeCq��(>.�)

Page 26: Whu beamer

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C°Ýo÷8ã«

b�©a�(Ç β = 0.8.

8Ü X �>.

X � β–eCq

X � β–>.�

�±w�C°Ý�{¦�eCq8O�!þCq8~�, l ¦8Ü£ã�°ÝO�.

Page 27: Whu beamer

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C°Ýo÷8�ÿнÂ

½Â (Katzberg & Ziarko (1996)[4])

?�8Ü X ∈ U Úá58 R, é 0 6 l < u 6 1, 8Ü X� l–eCq!u–þCq©O½Â�

Ru(X) =⋃ {

Xi ∈ U/R∣∣∣ Xi

u⊆X

}, (12)

Rl(X) =⋃ {

Xi ∈ U/R∣∣∣ Xi

l⊂X

}. (13)

Page 28: Whu beamer

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�z

Ü©?, Ç��, ù3�, o��.

o÷8nØ��{.

�ÆÑ��, �®, 2001.

Z. Pawlak.

Rough sets.

International Journal of Computer Information Science, 5:341–356,1982.

W. Ziarko.

Variable precision rough set model.

Journal of Computer and System Sciences, 46:39–59, 1993.

J. D. Katzberg and W. Ziarko.

Variable precision extension of rough sets.

Fundamenta Informaticae, 27:155–168, 1996.

Page 29: Whu beamer

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Thank you!

Author: HUANG Zheng-huaAddress: School of Mathematics & Statistics

Wuhan UniversityWuhan, 430072, China

Email: [email protected]