1. 2019/9/3
Adaptive Hashing Based Multiple Variable Length Pattern Search Algorithm for Large Data Sets
比對 Simple Pattern 的方法是基於 Hash 並且可以比對不同長度的 Pattern。
2015 IEEE Conference on Network Function Virtualization and Software Defined Network (ICDSE)
Author: Punit Kanuga, Anamika Chauhan
Presenter: Cheng-Feng Ke
Date: /09/27
Department of Computer Science and Information Engineering
National Cheng Kung University, Taiwan R.O.C.
CSIE CIAL Lab 1

2. Find Minimum Pattern Length
2019/9/3
INTRODUCTION
Simple Pattern
scare
scar
arch
Find Minimum Pattern Length
Create Hash Table
Create
Match Table
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

3. Find Minimum Pattern Length
2019/9/3
Find Minimum Pattern Length
scare (Length = 5)
scar (Length = 4)
arch (Length = 5)
Min Length 4
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

4. Create Hash Table Patterns: scare、scar 、arch Min Length 4 Hash Table
2019/9/3
Min Length 4
Create Hash Table
Patterns: scare、scar 、arch
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

5. Create Match Table Patterns: scare、scar 、arch sc、ca、ar、re、rc、ch
2019/9/3
Min Length 4
Create Match Table
Patterns: scare、scar 、arch sc、ca、ar、re、rc、ch
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Match Table
Key
Values
HASH(sc)
HASH(ca)
HASH(ar)
HASH(re)
HASH(rc)
HASH(ch)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

6. Create Match Table Patterns: scare、scar 、arch sc => scare、scar
2019/9/3
Min Length 4
Create Match Table
Patterns: scare、scar 、arch sc => scare、scar
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Match Table
Key
Values
HASH(sc)
(0)
HASH(ca)
HASH(ar)
HASH(re)
HASH(rc)
HASH(ch)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

7. Create Match Table Patterns: scare、scar 、arch sc => scare、scar
2019/9/3
Min Length 4
Create Match Table
Patterns: scare、scar 、arch sc => scare、scar
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Match Table
Key
Values
HASH(sc)
(0, 1)
HASH(ca)
HASH(ar)
HASH(re)
HASH(rc)
HASH(ch) 1 2 3 4 s c a r e
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

8. Create Match Table Patterns: scare、scar 、arch sc => scare、scar
2019/9/3
Min Length 4
Create Match Table
Patterns: scare、scar 、arch sc => scare、scar
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3)
HASH(ca)
HASH(ar)
HASH(re)
HASH(rc)
HASH(ch) 1 2 3 s c a r e
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

9. Create Match Table Patterns: scare、scar 、arch sc => scare、scar
2019/9/3
Min Length 4
Create Match Table
Patterns: scare、scar 、arch sc => scare、scar
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3), (1,1,1,2)
HASH(ca)
(0,2,2,2), (1,2,2,1)
HASH(ar)
(0,3,3,1), (1,3,3,0),(2,1,1,2)
HASH(re)
(0,4,4,0),
HASH(rc)
(2,2,2,1)
HASH(ch)
(2,3,3,0) 1 2 3 s c a r
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

10. Search Min Length 4 4 - 2 = 2 Hash Table Index Hash Value HASH(scare)
2019/9/3
Min Length 4
Search
4 - 2 = 2
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Input String -2 -1 1 2 3 4 5 6 7 8 a r e s c h ●
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3), (1,1,1,2)
HASH(ca)
(0,2,2,2), (1,2,2,1)
HASH(ar)
(0,3,3,1), (1,3,3,0),(2,1,1,2)
HASH(re)
(0,4,4,0)
HASH(rc)
(2,2,2,1)
HASH(ch)
(2,3,3,0)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

11. Search Min Length 4 Hash Table Index Hash Value HASH(scare) 1
2019/9/3
Min Length 4
Search
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Input String -2 -1 1 2 3 4 5 6 7 8 a r e s c h ●
2 - 4 = -2
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3), (1,1,1,2)
HASH(ca)
(0,2,2,2), (1,2,2,1)
HASH(ar)
(0,3,3,1), (1,3,3,0),(2,1,1,2)
HASH(re)
(0,4,4,0)
HASH(rc)
(2,2,2,1)
HASH(ch)
(2,3,3,0)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

12. Search Min Length 4 Hash Table Index Hash Value HASH(scare) 1
2019/9/3
Min Length 4
Search
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Input String -2 -1 1 2 3 4 5 6 7 8 a r e s c h ●
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3), (1,1,1,2)
HASH(ca)
(0,2,2,2), (1,2,2,1)
HASH(ar)
(0,3,3,1), (1,3,3,0),(2,1,1,2)
HASH(re)
(0,4,4,0)
HASH(rc)
(2,2,2,1)
HASH(ch)
(2,3,3,0)
2 + 4 – 1 = 5
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

13. Search Min Length 4 Hash Table Index Hash Value HASH(scare) 1
2019/9/3
Min Length 4
Search
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Input String -2 -1 1 2 3 4 5 6 7 8 a r e s c h ●
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3), (1,1,1,2)
HASH(ca)
(0,2,2,2), (1,2,2,1)
HASH(ar)
(0,3,3,1), (1,3,3,0),(2,1,1,2)
HASH(re)
(0,4,4,0)
HASH(rc)
(2,2,2,1)
HASH(ch)
(2,3,3,0)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

14. Search Min Length 4 Hash Table Index Hash Value HASH(scare) 1
2019/9/3
Min Length 4
Search
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Input String -2 -1 1 2 3 4 5 6 7 8 a r e s c h ●
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3), (1,1,1,2)
HASH(ca)
(0,2,2,2), (1,2,2,1)
HASH(ar)
(0,3,3,1), (1,3,3,0),(2,1,1,2)
HASH(re)
(0,4,4,0)
HASH(rc)
(2,2,2,1)
HASH(ch)
(2,3,3,0)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

15. Search Min Length 4 Hash Table Index Hash Value HASH(scare) 1
2019/9/3
Min Length 4
Search
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Input String -2 -1 1 2 3 4 5 6 7 8 a r e s c h ●
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3), (1,1,1,2)
HASH(ca)
(0,2,2,2), (1,2,2,1)
HASH(ar)
(0,3,3,1), (1,3,3,0),(2,1,1,2)
HASH(re)
(0,4,4,0)
HASH(rc)
(2,2,2,1)
HASH(ch)
(2,3,3,0)
HASH( input[3-7] ) == HASH(scare)
Match List
(3, 7)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

16. Search Min Length 4 Hash Table Index Hash Value HASH(scare) 1
2019/9/3
Min Length 4
Search
Hash Table
Index
Hash Value
HASH(scare) 1
HASH(scar) 2
HASH(arch)
Input String -2 -1 1 2 3 4 5 6 7 8 a r e s c h ●
Match Table
Key
Values
HASH(sc)
(0, 1, 1, 3), (1,1,1,2)
HASH(ca)
(0,2,2,2), (1,2,2,1)
HASH(ar)
(0,3,3,1), (1,3,3,0),(2,1,1,2)
HASH(re)
(0,4,4,0)
HASH(rc)
(2,2,2,1)
HASH(ch)
(2,3,3,0)
HASH( input[3-6] ) == HASH(scar)
Match List
(3, 7)
(3, 6)
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

17. 2019/9/3
EVALUATION
Implementation of proposed algorithm is done in C language on Code::Blocks version
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

18. EVALUATION Search Time (ms) Input String Length
2019/9/3
EVALUATION
Search Time
(ms)
Input String Length
Number of patterns is kept fixed and length of Input String is varied from 10,000 to 200,000, this algorithm takes searching time of O(n/P) for Input String of length n.
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab

19. EVALUATION Search Time (ms) Number of Patterns
2019/9/3
EVALUATION
Search Time
(ms)
Number of Patterns
Input String length is kept fixed (100,000) and number of patterns are increased from 3 to 21 keeping length of smallest pattern same among all sets.
National Cheng Kung University CSIE Computer & Internet Architecture Lab
CSIE CIAL Lab