Study on the Automation Method of Regular Expression to Finite Automaton

2010 ◽  
Vol 34-35 ◽  
pp. 1493-1496
Author(s):  
Qiong Cao ◽  
Xian Ying Huang ◽  
Ke Ke Wang ◽  
Jing Yin
Keyword(s):  
Finite Automaton ◽  
Regular Expression

Regular expression was the foundation of advanced language and compiler. It can be recognized by finite automaton. In this paper, combined with operator priority analysis and the rules of regular expression, the table of priority relationship between operators involved in regular expression has be constructed. Based on the table, realized the automatic convert from regular expression to finite automaton, and the program is given. It provided a new reference of regular expression convert to finite automaton.

scholarly journals Packet Payload Monitoring for Internet Worm Content Detection Using Deterministic Finite Automaton with Delayed Dictionary Compression

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Divya Selvaraj ◽  
Padmavathi Ganapathi
Keyword(s):  
Finite Automaton ◽  
Regular Expression ◽  
Deterministic Finite Automaton ◽  
Memory Space ◽  
Internet Worm ◽  
Regular Expression Matching ◽  
Monitoring Applications ◽  
Communication Links ◽  
Worm Attacks ◽  
Memory Utilization

Packet content scanning is one of the crucial threats to network security and network monitoring applications. In monitoring applications, payload of packets in a network is matched against the set of patterns in order to detect attacks like worms, viruses, and protocol definitions. During network transfer, incoming and outgoing packets are monitored in depth to inspect the packet payload. In this paper, the regular expressions that are basically string patterns are analyzed for packet payloads in detecting worms. Then the grouping scheme for regular expression matching is rewritten using Deterministic Finite Automaton (DFA). DFA achieves better processing speed during regular expression matching. DFA requires more memory space for each state. In order to reduce memory utilization, decompression technique is used. Delayed Dictionary Compression (DDC) is applied for achieving better speeds in the communication links. DDC achieves decoding latency during compression of payload packets in the network. Experimental results show that the proposed approach provides better time consumption and memory utilization during detection of Internet worm attacks.

scholarly journals Set difference operation for regular Petri net languages for the producer/consumer problem with the bounded buffer

2021 ◽  
pp. 94-112
Author(s):  
Vitalii Statkevych
Keyword(s):  
Petri Net ◽  
Finite Automaton ◽  
Regular Expression ◽  
Formal Languages ◽  
Reachability Graph ◽  
Explicit Formulas ◽  
Elimination Method ◽  
Difference Operation ◽  
Consumer Problem ◽  
Synchronization Problems

We consider a Petri net for the producer/consumer problem (one of the classical synchronization problems) with the bounded buffer of size n and the regular formal languages Ln, generated by the net. The objective of this paper is to obtain a regular expression for the set difference of languages Ln \ Lm, n > m. For this purpose, we give the finite automaton which accepts the set difference of mentioned languages, and then we use the state elimination method to obtain the regular expression in the recursive form. The main result is illustrated by the examples. In an appendix, we consider the problem with two producers and two consumers with the bounded buffer of size 1. We give a reachability graph and propose the method for obtaining the regular expression. The explicit formulas are given for the problem with two producers and one consumer and also for the problem with one producer and two consumers.

PROVABLY SHORTER REGULAR EXPRESSIONS FROM FINITE AUTOMATA

2013 ◽  
Vol 24 (08) ◽  
pp. 1255-1279 ◽  
Author(s):  
HERMANN GRUBER ◽  
MARKUS HOLZER
Keyword(s):  
Graph Theory ◽  
Finite Automaton ◽  
Regular Expression ◽  
Finite Automata ◽  
Upper Bounds ◽  
Extremal Graph ◽  
Extremal Graph Theory ◽  
Regular Expressions ◽  
Deterministic Finite Automaton

Based on recent results from extremal graph theory, we prove that every n-state binary deterministic finite automaton can be converted into an equivalent regular expression of size O(1.742n) using state elimination. Furthermore, we give improved upper bounds on the language operations intersection and interleaving on regular expressions.

Improvement in Look-ahead Matching Hardware for Regular Expression

2016 ◽  
Vol 136 (10) ◽  
pp. 692-697
Author(s):  
Shuto Higa ◽  
Chikatoshi Yamada ◽  
Kei Miyagi ◽  
Shuichi Ichikawa
Keyword(s):  
Regular Expression ◽  
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