• Title/Summary/Keyword: String algorithms

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Development of the Pattern Matching Engine using Regular Expression (정규 표현식을 이용한 패턴 매칭 엔진 개발)

  • Ko, Kwang-Man;Park, Hong-Jin
    • 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.

Sway Control of Container Cranes as an Axially Moving Nonlinear String

  • Park, Hahn;Hong, Keum-Shik
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2474-2479
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    • 2005
  • The control objectives in this paper are to move the gantry of a container crane to its target position and to suppress the transverse vibration of the payload. The crane system is modeled as an axially moving nonlinear string equation, in which control inputs are applied at both ends, through the gantry and the payload. The dynamics of the moving string are derived using Hamilton's principle. The Lyapunov function method is used in deriving a boundary control law, in which the Lyapunov function candidate is introduced from the total mechanical energy of the system. The performance of the proposed control law is compared with other two control algorithms available in the literature. Experimental results are given.

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Boundary Control of Container Cranes as an Axially Moving String System (축방향으로 이동하는 현의 경계제어)

  • Park, Hahn;Hong, Keum-Shik
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.387-392
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    • 2004
  • The control objectives in this paper are to move the gantry of a container crane to its target position and to suppress the transverse vibration of the payload. The crane system is modeled as an axially moving string equation, in which control inputs are applied at both ends, through the gantry and the payload. The dynamics of the moving string are derived using Hamilton's principle for systems with changing mass. The Lyapunov function method is used in deriving a boundary control law, in which the Lyapunov function candidate is introduced from the total mechanical energy of the system. The performance of the proposed control law is compared with other two control algorithms available in the literature. Experimental results are given.

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Parallel Approximate String Matching with k-Mismatches for Multiple Fixed-Length Patterns in DNA Sequences on Graphics Processing Units (GPU을 이용한 다중 고정 길이 패턴을 갖는 DNA 시퀀스에 대한 k-Mismatches에 의한 근사적 병열 스트링 매칭)

  • Ho, ThienLuan;Kim, HyunJin;Oh, SeungRohk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.6
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    • pp.955-961
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    • 2017
  • In this paper, we propose a parallel approximate string matching algorithm with k-mismatches for multiple fixed-length patterns (PMASM) in DNA sequences. PMASM is developed from parallel single pattern approximate string matching algorithms to effectively calculate the Hamming distances for multiple patterns with a fixed-length. In the preprocessing phase of PMASM, all target patterns are binary encoded and stored into a look-up memory. With each input character from the input string, the Hamming distances between a substring and all patterns can be updated at the same time based on the binary encoding information in the look-up memory. Moreover, PMASM adopts graphics processing units (GPUs) to process the data computations in parallel. This paper presents three kinds of PMASM implementation methods in GPUs: thread PMASM, block-thread PMASM, and shared-mem PMASM methods. The shared-mem PMASM method gives an example to effectively make use of the GPU parallel capacity. Moreover, it also exploits special features of the CUDA (Compute Unified Device Architecture) memory structure to optimize the performance. In the experiments with DNA sequences, the proposed PMASM on GPU is 385, 77, and 64 times faster than the traditional naive algorithm, the shift-add algorithm and the single thread PMASM implementation on CPU. With the same NVIDIA GPU model, the performance of the proposed approach is enhanced up to 44% and 21%, compared with the naive, and the shift-add algorithms.

Variable length Chromosomes in Genetic Algorithms for Modeling the Class Boundaries

  • Bandyopadhyay, Sanghamitra;Pal, Sankar K.;Murthy, C.A.
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.06a
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    • pp.634-639
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    • 1998
  • A methodology based on the concept of variable string length GA(VGA) is developed for determining automatically the number of hyperplanes and their appropriate arrangement for modeling the class boundaries of a given training data set in RN. The genetic operators and fitness functionare newly defined to take care of the variability in chromosome length. Experimental results on different artificial and real life data sets are provided.

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Design of a Padding Algorithm Using the Pad Character Length (패딩 문자열 길이 정보를 이용한 패딩 알고리즘 설계)

  • Jang, Seung-Ju
    • Journal of Korea Multimedia Society
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    • v.9 no.10
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    • pp.1371-1379
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    • 2006
  • This paper suggests the padding algorithm using padding character length to concatenate more than one string without side-effect. Most existing padding algorithms padding null character in the empty location could not discriminate the real string from the padded character. To overcome this problem, in this paper, the padded character contains pad character length information. This mechanism is working better than NULL or '00' padding cases. The suggested padding algorithm could be effective for data encryption and decryption algorithms.

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Power Gain during Partial Shade Condition with Partial Shade Loss Compensation in Photovoltaic System

  • Yoon, Byung-Keun;Yun, Chul;Cho, Nae-Soo;Choi, Sang-Back;Jin, Yong-Su;Kwon, Woo-Hyen
    • Journal of Electrical Engineering and Technology
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    • v.13 no.2
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    • pp.769-780
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    • 2018
  • This paper presents an analysis of the power gain under partial shading conditions (PSC) when the partial shade loss is being compensated in photovoltaic(PV) system. To analyze the power gain, our study divides the mismatch loss into partial shade loss and operating point loss. Partial shade loss is defined as the power difference between a normal string and a partially shaded string at the maximum power point (MPP). Operating point loss is defined as the power loss due to the operating point shift while following the MPP of the PV array. Partial shading in a PV system affects the maximum power point tracking (MPPT) control by creating multiple MPPs, which causes mismatch losses. Several MPPT algorithms have been suggested to solve the multiple MPP problems. Among these, mismatch compensation algorithms require additional power to compensate for the mismatch loss; however, these algorithms do not consider the gain or loss between the input power required for compensation and the increased output power obtained after compensation. This paper analyzes the power gain resulting from the partial shade loss compensation under PSC, using the V-P curve of the PV system, and verifies that power gain existence by simulation and experiment.

Performance Comparison on Pattern Recognition Between DNA Coding Method and GA Coding Method (DNA 코딩방법과 GA 코딩방법의 패턴인식 성능 비교에 관한 연구)

  • 백동화;한승수
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2002.12a
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    • pp.383-386
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    • 2002
  • In this paper, we investigated the pattern recognition performance of the numeric patterns (from 0 to 9) using DNA coding method. The pattern recognition performance of the DNA coding method is compared to the that of the GA(Genetic Algorithm). GA searches effectively an optimal solution via the artificial evolution of individual group of binary string using binary coding, while DNA coding method uses four-type bases denoted by A(Adenine), C(Cytosine), G(Guanine) and T(Thymine), The pattern recognition performance of GA and DNA coding method is evaluated by using the same genetic operators(crossover and mutation) and the crossover probability and mutation probability are set the same value to the both methods. The DNA coding method has better characteristics over genetic algorithms (GA). The reasons for this outstanding performance is multiple possible solution presentation in one string and variable solution string length.

String Matching Algorithm on Multi-byte Character Set Texts (다중바이트 문자집합 텍스트에서의 문자열 검색 알고리즘)

  • Kim, Eun-Sang;Kim, Jin-Wook;Park, Kun-Soo
    • Journal of KIISE:Computing Practices and Letters
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    • v.16 no.10
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    • pp.1015-1019
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    • 2010
  • An extensive research on exact string matching has been done, but there have been few researches on the matching in multi-byte character set texts such as EUC~KR. This paper shows that false matches may occur in multi-byte character set texts such as EUC-KR when using KMP algorithm, and presents a refined KMP algorithm without false matches applying a character-based prefix function. And also, Experimental results show that our algorithm is faster than string matching algorithms of widely used editors, Vim and Emacs, and the existing automata-based algorithm.

Analysis of Partnering Strategies in Symbiotic Evolutionary Algorithms (공생진화 알고리듬에서의 공생파트너 선택전략 분석)

  • 김재윤;김여근;신태호
    • Journal of the Korean Operations Research and Management Science Society
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    • v.25 no.4
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    • pp.67-80
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    • 2000
  • Symbiotic evolutionary algorithms, also called cooperative coevolutionary algorithms, are stochastic search algorithms that imitate the biological coevolution process through symbiotic interactions. In the algorithms, the fitness evaluation of an individual required first selecting symbiotic partners of the individual. Several partner selection strategies are provided. The goal of this study is to analyze how much partnering strategies can influence the performance of the algorithms. With two types of test-bed problems: the NKC model and the binary string covering problem, extensive experiments are carried out to compare the performance of partnering strategies, using the analysis of variance. The experimental results indicate that there does not exist statistically significant difference in their performance.

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