• The Journal of the Korea Contents Association
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• v.8 no.2
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• pp.33-40
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• 2008

In various manners, string pattern matching algorithm has been proven for prominence in speed of searching particular queries and keywords. Whereas, the existing algorithms are limited in terms of various pattern. In this paper, regular expression has been utilized to improve efficiency of pattern matching through efficient execution towards various pattern of queries including particular keywords. Such as this research would enable to search various harmful string pattern more efficiently, rather than matching simple keywords, which also implies excellent speed of string pattern matching compared to that of those existing algorism. In this research, the proposed string search engine generated from the LEX are more efficient than BM & AC algorithm for a string patterns search speed in cases of 1000 with more than patterns, but we have got similar results for the keywords pattern matching.

• Smart Media Journal
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• v.9 no.2
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• pp.33-38
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• 2020

Order preserving matching refers to the problem of reporting substrings of a given text where there exists order isomorphism with the pattern. In this paper, we propose a new algorithm based on filtering and evaluation. The proposed algorithm is simple and easy to implement, and runs in linear time on average. Experimental results show that it works efficiently with real world data.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2253-2261
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• 1999

ACK generates optimized code using the string pattern matching technique in pattern table generator and peephole optimizer. But string pattern matching method is not effective due to the many comparative actions in pattern selection. We designed and implemented the EM intermediate code optimizer using tree pattern matching algorithm composed of EM tree generator, optimization pattern table generator and tree pattern matcher. Tree pattern matching algorithm practices the pattern matching that centering around root node with refer to the pattern table, with traversing the EM tree by top-down method. As a result, compare to ACK string pattern matching methods, we found that the optimized code effected to pattern selection time, and contributed to improved the pattern selection time by about 10.8%.

• Journal of KIISE
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• v.43 no.5
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• pp.509-515
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• 2016

Given a text T and a pattern P, the order-preserving pattern matching problem is to find all substrings in T which have the same relative orders as P. The order-preserving pattern matching problem has been studied in terms of finding some patterns affected by relative orders, not by their absolute values. Given a text T and a pattern set $\mathbb{P}$, the order-preserving multiple pattern matching problem is to find all substrings in T which have the same relative orders as any pattern in $\mathbb{P}$. In this paper, we present a hashing-based algorithm for the order-preserving multiple pattern matching problem.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.86-94
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• 2009

Currently, positioning methods for LBS(Location Based Service) are GPS and network-based positioning techniques that use mobile communication networks. In these methods, however, the accuracy of positioning decreases due to the propagation delay caused by the non-line-of-sight(NLOS) effect and the repeater. To address this disadvantage, the CDMA system uses Pattern Matching algorithm. The Pattern Matching algorithm constructs a database of the propagation characteristics of the RF signals measured during the GPS positioning along with the positioned locations, so that the location can be provided by comparing the propagation characteristics of the received signals and the database, upon a user's request. In the area where GPS signals are not received, however, a database cannot be constructed. There are problem that the accuracy of positioning decreases due to the area without a database Because Pattern Matching algorithm depend on database existence. Therefore, this paper proposed a pilot signal strength prediction algorithm to enable construction of databases for areas without databases, so as to improve the performance of the Pattern Matching algorithm. The database was constructed by predicting the pilot signals in the area without a database using the proposed algorithm, and the Pattern Matching algorithm analysed positioning performance.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.110-116
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• 2014

Pattern matching algorithms are widely used in computer security systems such as computer networks, ubiquitous networks, sensor networks, and so on. However, the advances in information technology causes grow on the amount of data and increase on the computation complexity of pattern matching processes. Therefore, there is a strong demand for a novel high performance pattern matching algorithms. In light of this fact, this paper newly proposes a suffix tree based pattern matching algorithm. The suffix tree is constructed based on the suffix values of all patterns. Then, the shift nodes which informs how many characters can be skipped without matching operations are added to the suffix tree in order to boost matching performance. The proposed algorithm reduces memory usage on the suffix tree and the amount of matching operations by the shift nodes. From the performance evaluation, our algorithm achieved 24% performance gain compared with the traditional algorithm named as Wu-Manber.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.853-856
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• 2000

최근 정보통신 관련 시장의 양적 팽창과 함께 발생된 수많은 시스템 침입 사건들은 컴퓨터 보안 문제와 이를 해결하기 위한 보안 시스템에 대한 관심을 증가시키고 있다. 침입탐지시스템은 보안 시스템의 핵심 요소로, 그 중 대부분이 패턴 매칭을 이용한 침입탐지방식을 채택하고 있다. 그러나 현재의 패턴 매칭을 위한 알고리즘은 유연하지 못하기 때문에, 다양한 특성을 지닌 공격들에 대한 대처 능력이 부족하다. 이를 해결하기 위해 본 논문에서는 패턴들의 특성에 따라 유연하게 대처할 수 있는 세 가지의 유사 패턴 매칭 알고리즘을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.57-60
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• 2020

순위다중패턴매칭문제는 길이가 n인 텍스트 T와 패턴들의 집합 P' = {P₁,P₂…,P_k}가 주어졌을 때, P'에 속하는 패턴들과 상대적인 순위가 일치하는 T의 모든 부분문자열들의 위치를 찾는 문제이다. P'에서 가장 짧은 패턴의 길이가 m, 가장 긴 패턴의 길이를 $\bar{m}$, 모든 패턴들의 길이의 합을 M, q개의 연속된 문자들을 q-그램이라 할 때, 기존에 텍스트의 핑거프린트를 이용하여 순위다중패턴매칭문제를 $O(q!+nqlogq+Mlog\bar{m}+nM)$ 시간에 해결하는 알고리즘이 제시되었다. 본 논문에서는 텍스트의 핑거프린트를 활용하여 O(max(q!,M,n))개의 스레드를 이용하여 순위다중패턴매칭문제를 평균적으로 $O(\bar{m}+qlogq+n/q!)$ 시간에 해결하는 병렬 구현 방법을 제시한다. 실험 결과, n = 1,000,000, k = 1,000, m = 5, q = 3일 때, 본 논문에서 제시하는 병렬 구현 방법은 기존의 순차 알고리즘보다 약 19.8배 빠르게 수행되었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.36-39
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• 2017

길이가 같은 두 문자열의 같은 위치에 있는 문자의 순위가 모두 일치할 때, 두 문자열은 순위동형이라 한다. 순위다중패턴매칭문제는 텍스트 T와 k개의 패턴들의 집합 $P^{\prime}=\{P_1,P_2{\ldots},P_k\}$이 주어졌을 때, P'의 패턴들과 순위동형인 T의 모든 부분문자열의 위치를 찾는 문제이다. 최근 전처리단계에서 P'에 대한 이동테이블을 O(kmqlogq) 시간에 계산하여 순위다중패턴매칭문제를 해결하는 해싱기반 알고리즘이 제시되었다. 이때 P'에서 가장 짧은 패턴의 길이를 m, q-그램의 길이를 q라고 한다. 본 논문에서는 P'이 주어졌을 때, 이동테이블을 O(mqlogq) 시간에 계산하는 병렬알고리즘을 제시한다. 실험결과, 본 논문에서 제시하는 병렬알고리즘은 k개의 스레드를 이용하여 m=100, q=5에 대해 k=100일때와 k=1,000일 때 순차알고리즘보다 각각 약 12.9배, 약 215배 빠른 수행시간을 보였다.

• Journal of the Korea society of information convergence
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• v.7 no.2
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• pp.59-65
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• 2014

Grassfire spot matching method is based on similarity comparison of topological patterns for neighbor spots. This is a method where spot matching is performed as if fire spreads all around on grass. Spot matching starts from a seed spot pair confirmed as a matched pair of spots and spot matching spreads to the direction where the best matching result is produced. In this paper, it is a bit complicated way of grassfire method where multi-seed matched spot pair are manually selected and spot matching is performed from each multi-seed matched spot pair. The proposed method shows better performance in detection rate and accuracy than that of the previous method.