• Title/Summary/Keyword: n그램

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Accurate Intrusion Detection using n-Gram Augmented Naive Bayes (N-Gram 증강 나이브 베이스를 이용한 정확한 침입 탐지)

  • Kang, Dae-Ki
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.10a
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    • pp.285-288
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    • 2008
  • In many intrusion detection applications, n-gram approach has been widely applied. However, n-gram approach has shown a few problems including double counting of features. To address those problems, we applied n-gram augmented Naive Bayes directly to classify intrusive sequences and compared performance with those of Naive Bayes and Support Vector Machines (SVM) with n-gram features by the experiments on host-based intrusion detection benchmark data sets. Experimental results on the University of New Mexico (UNM) benchmark data sets show that the n-gram augmented method, which solves the problem of independence violation that happens when n-gram features are directly applied to Naive Bayes (i.e. Naive Bayes with n-gram features), yields intrusion detectors with higher accuracy than those from Naive Bayes with n-gram features and shows comparable accuracy to those from SVM with n-gram features.

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Scalable and Accurate Intrusion Detection using n-Gram Augmented Naive Bayes and Generalized k-Truncated Suffix Tree (N-그램 증강 나이브 베이스 알고리즘과 일반화된 k-절단 서픽스트리를 이용한 확장가능하고 정확한 침입 탐지 기법)

  • Kang, Dae-Ki;Hwang, Gi-Hyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.4
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    • pp.805-812
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    • 2009
  • In many intrusion detection applications, n-gram approach has been widely applied. However, n-gram approach has shown a few problems including unscalability and double counting of features. To address those problems, we applied n-gram augmented Naive Bayes with k-truncated suffix tree (k-TST) storage mechanism directly to classify intrusive sequences and compared performance with those of Naive Bayes and Support Vector Machines (SVM) with n-gram features by the experiments on host-based intrusion detection benchmark data sets. Experimental results on the University of New Mexico (UNM) benchmark data sets show that the n-gram augmented method, which solves the problem of independence violation that happens when n-gram features are directly applied to Naive Bayes (i.e. Naive Bayes with n-gram features), yields intrusion detectors with higher accuracy than those from Naive Bayes with n-gram features and shows comparable accuracy to those from SVM with n-gram features. For the scalable and efficient counting of n-gram features, we use k-truncated suffix tree mechanism for storing n-gram features. With the k-truncated suffix tree storage mechanism, we tested the performance of the classifiers up to 20-gram, which illustrates the scalability and accuracy of n-gram augmented Naive Bayes with k-truncated suffix tree storage mechanism.

Grouping of Similar Programs using Program Similarity Evaluation (프로그램 유사도 평가를 이용한 유사 프로그램의 그룹 짓기)

  • 유재우;김영철
    • Journal of KIISE:Software and Applications
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    • v.31 no.1
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    • pp.82-88
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    • 2004
  • Comparing many programs like programming assignments one by one requires many costs. Moreover, if the checker would evaluate or grade assignments, much more time will be required. Even through the checker invest much time, fairness is not always guaranteed. These problems can be solved easily by grouping similar programs. So, programs after grouping can be easily evaluated and graded. In this paper, we propose and implement algerian performing grouping by similarity on many programs. The grouping algorithm evaluates similarity using algorithm proposed in (9), and performs a grouping following high similarity order. By using this grouping algorithm, the number of comparison among N programs can be reduced from N-1 times to N(N-1)/2 times. In the part of experiment and evaluation of this paper, we actually showed evaluation result by similarity using randomly 10 programming assignments at the university.

A Linear-time Algorithm for Computing the Spherical Voronoi Diagram of Unit Normal Vectors of a Convex Polyhedron (볼록 다면체 단위 법선 벡터의 구면 보로노이 다이아그램을 계산하기 위한 선형시간 알고리즘)

  • Kim, Hyeong-Seok
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.10
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    • pp.835-839
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    • 2000
  • 보로노이 다이아그램은 계산기하학에서 다양한 형태의 근접 문제를 해결함에 있어 중요한 역할을 하고 있다. 일반적으로 평면상의 n 개의 점에 의한 평면 보로노이 다이아그램 O(nlogn) 시간에 생성할 수 있으며 이 알고리즘의 시간 복잡도가 최적임이 밝혀져 있다. 본 논문에서는 특별한 관계를 갖는 단위 구면상의 점들에 대한 구면 상에서 정의되는 보로노이 다이아그램을 O(n)에 생성하는 알고리즘을 제시한다. 이때 주어진 구면상의 점들은 볼록 다면체의 단위 법선 벡터들의 종점에 해당되며, 구면 보로노이 다이아그램의 선분은 구면상의 geodesic으로 이루어진다.

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Part-Of-Speech Tagging using multiple sources of statistical data (이종의 통계정보를 이용한 품사 부착 기법)

  • Cho, Seh-Yeong
    • Journal of the Korean Institute of Intelligent Systems
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    • v.18 no.4
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    • pp.501-506
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    • 2008
  • Statistical POS tagging is prone to error, because of the inherent limitations of statistical data, especially single source of data. Therefore it is widely agreed that the possibility of further enhancement lies in exploiting various knowledge sources. However these data sources are bound to be inconsistent to each other. This paper shows the possibility of using maximum entropy model to Korean language POS tagging. We use as the knowledge sources n-gram data and trigger pair data. We show how perplexity measure varies when two knowledge sources are combined using maximum entropy method. The experiment used a trigram model which produced 94.9% accuracy using Hidden Markov Model, and showed increase to 95.6% when combined with trigger pair data using Maximum Entropy method. This clearly shows possibility of further enhancement when various knowledge sources are developed and combined using ME method.

Comparison Program Language in the Android System (안드로이드 시스템에서 프로그램 언어 비교 연구)

  • Janf, Seung Ju;Kim, Seung Jin
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.10a
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    • pp.681-684
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    • 2013
  • This paper compares the Java program environments and NDK program environments in the Android system. This paper experiments that how much is the performance enhancement in the NDK C programming of the Android system. I program sum of 1 to n for Java program and NDK C program. I experiment whether the influence an effect on a performance by changing n value. In experiment, NDK C program is over 50% performance enhancement than Java program.

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The Study of Wavefront Aberration Reconstruction for Optical System (광학계의 파면수차 재구성에 대한 연구)

  • Park, Seong-Jong;Ju, Seok-Hee;Kim, Sung-Gyun
    • Journal of Korean Ophthalmic Optics Society
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    • v.10 no.4
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    • pp.357-364
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    • 2005
  • To develope the assessment equpiments of an optical system using adaptive optics, we developed the program of wavefront reconstruction for an optical system like eye. We used matlab in order to program the wavefront reconstruction for an optical system and presented the wavefront function of optical system by the zemike polynomials using modal method. To test the developed program, we calculated the zemike coefficient(n=7) of cooke triplet using code V, and compared the wavefront shape and the zemike polynomials using code V to those using the developed program. In this case, the used zemike coefficients were n=2, 3, 4, 5, 6, 7, 8, 9, and 10 and the number of sub-aperture were 1,253. From these results, we know that the reconstructed wavefronts were similar to the wavefront of cooke triplet as n was the larger than 4 and the zemike coefficient was equal to that of cooke triplet as n was 7. The developed program is able to be applied to the core technology to develope the assessment equipment of an optical system using the adaptive optics.

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Comparison between Nl -N2 Audiograms of Guinea Pigs pre and post loudtone exposure (격음 노출 전후의 기니픽 N1-N2 오디오그램의 비교)

  • 장순석
    • Journal of Biomedical Engineering Research
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    • v.16 no.4
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    • pp.471-480
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    • 1995
  • The modification of Nl -N2 Audiograms before and after loudtone exposure onto the tympanic membrane of guinea pigs was examined. The exposure was a loud continuous tone of 106 dB SPL intensity at 10 KHz for 10 minutes. The comparison between Wl-H2 Audiograms pre and post loudtone exposure indicates that the exposed cochlea permanently lost its normal hearing function. The largest threshold shifts wore found between 12-13.2KHz. The functional change of the cochlea after the loudtone exposure depends on the state of the cochlea before the trauma. More sensitive cochlea is more critically damaged in its function after the trauma than less sensitive cochlea.

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An Efficient Authentication Scheme for Downloading and Updating Applications in Smart Cards (스마트 카드 응용 프로그램의 다운로드와 갱신에 대한 효율적인 인증 기법)

  • 박용수;조유근
    • Journal of KIISE:Computer Systems and Theory
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    • v.31 no.1_2
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    • pp.118-124
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    • 2004
  • In this paper we propose a method for authenticating the application that is to be downloaded or updated in smart cards. Previous works have some drawbacks such as having a long verification delay or requiring a large amount of primary/secondary storage. We propose an efficient parameterized scheme by using the hash chain technique where the secondary storage requirement and verification delay of updating the application are O(k) and O(k+n/k), respectively. Moreover, both the first storage requirement and verification delay of downloading the application are O(1).

A Sequence of the Extreme Vertices ova Moving Regular Polyhedron Using Spherical Voronoi Diagrams (구면 보로노이 다이아그램을 이용한 움직이는 정규 다면체의 근점 알고리즘)

  • 김형석
    • Journal of Korea Multimedia Society
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    • v.3 no.3
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    • pp.298-308
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    • 2000
  • We present an efficient algorithm for finding the sequence of extreme vortices of a moving regular convex polyhedron of with respect to a fixed plane H.. The algorithm utilizes the spherical Voronoi diagram that results from the outward unit normal vectors nF$_{i}$ 's of faces of P. It is well-known that the Voronoi diagram of n sites in the plane can be computed in 0(nlogn) time, and this bound is optimal. However. exploiting the convexity of P, we are able to construct the spherical Voronoi diagram of nF$_{i}$ ,'s in O(n) time. Using the spherical Voronoi diagram, we show that an extreme vertex problem can be transformed to a spherical point location problem. The extreme vertex problem can be solved in O(logn) time after O(n) time and space preprocessing. Moreover, the sequence of extreme vertices of a moving regular convex polyhedron with respect to H can be found in (equation omitted) time, where m$^{j}$ $_{k}$ (1$\leq$j$\leq$s) is the number of edges of a spherical Voronoi region sreg(equation omitted) such that (equation omitted) gives one or more extreme vertices.

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