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Plagiarism Detection among Source Codes using Adaptive Methods

  • Lee, Yun-Jung;Lim, Jin-Su;Ji, Jeong-Hoon;Cho, Hwaun-Gue;Woo, Gyun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.6
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    • pp.1627-1648
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    • 2012
  • We propose an adaptive method for detecting plagiarized pairs from a large set of source code. This method is adaptive in that it uses an adaptive algorithm and it provides an adaptive threshold for determining plagiarism. Conventional algorithms are based on greedy string tiling or on local alignments of two code strings. However, most of them are not adaptive; they do not consider the characteristics of the program set, thereby causing a problem for a program set in which all the programs are inherently similar. We propose adaptive local alignment-a variant of local alignment that uses an adaptive similarity matrix. Each entry of this matrix is the logarithm of the probabilities of the keywords based on their frequency in a given program set. We also propose an adaptive threshold based on the local outlier factor (LOF), which represents the likelihood of an entity being an outlier. Experimental results indicate that our method is more sensitive than JPlag, which uses greedy string tiling for detecting plagiarism-suspected code pairs. Further, the adaptive threshold based on the LOF is shown to be effective, and the detection performance shows high sensitivity with negligible loss of specificity, compared with that using a fixed threshold.

A Study on Automatic Classification of Fingerprint Images (지문 영상의 자동 분류에 관한 연구)

  • Lim, In-Sic;Sin, Tae-Min;Park, Goo-Man;Lee, Byeong-Rae;Park, Kyu-Tae
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.628-631
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    • 1988
  • This paper describes a fingerprint classification on the basis of feature points(whorl, core) and feature vector and uses a syntactic approach to identify the shape of flow line around the core. Fingerprint image is divided into 8 by 8 subregions and fingerprint region is separated from background. For each subregion of fingerprint region, the dominant ridge direction is obtained to use the slit window quantized in 8 direction and relaxation is performed to correct ridge direction code. Feature points(whorl, core, delta) are found from the ridge direction code. First classification procedure divides the types of fingerprint into 4 class based on whorl and cores. The shape of flow line around the core is obtained by tracing for the fingerprint which has one core or two core and is represented as string. If the string is acceptable by LR(1) parser, feature vector is obtained from feature points(whorl, core, delta) and the shape of flow line around the core. Feature vector is used hierarchically and linearly to classify fingerprint again. The experiment resulted in 97.3 percentages of sucessful classification for 71 fingerprint impressions.

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Studies on the Acoustical Characteristics of Violin Bridges and SDM Simulation (바이올린 브릿지의 음향적 특성 및 SDM 시뮬레이션에 관한 연구)

  • 정우양
    • Journal of the Korea Furniture Society
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    • v.12 no.1
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    • pp.47-55
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    • 2001
  • Violin bridge blank cut from maple wood with good quality has typical pattern of the radial direction in the side edge with minimal dispersion. This experimental study was designed and carried out to examine the effect of the physical and macroscopical characteristics on the compressive creep of violin bridge blank which had been imported from European manufacturer. This research arose from the idea that the maple solid wood with heterogeneous wood density and ray direction in the side edge would have uneven rheological property of violin bridge blank which is supposed to be pressed by the tension of strings. Experimentally, the compressive creep of bridge blank became smaller with the higher density of imported maple wood and showed clear density-dependence for the duration of load under the string tension of 5 kgf. Every bridge blank showed the behavior of primary creep stage(stress stabilization) having logarithmic regression creep curve with high correlation coefficient under the designed stress level. Even though the relationship between compressive creep and ray direction on the side edge of bridge was not so clear contrary to expectation, we could conclude that wood density and ray direction should be the quality decisive factors affecting the acoustical characteristics and performance of the bridge, the core member of violin-family bow instruments.

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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.

A Tree-Compare Algorithm for Similarity Evaluation (유사도 평가를 위한 트리 비교 알고리즘)

  • Kim, Young-Chul;Yoo, Chae-Woo
    • The KIPS Transactions:PartA
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    • v.11A no.2
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    • pp.159-164
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    • 2004
  • In the previous researches, tree comparison methods are almost studied in comparing weighted or labeled tree(decorated tree). But in this paper, we propose a tree comparison and similarity evaluation algorithm can be applied to comparison of two normal trees. The algorithm converts two trees into node string using unparser, evaluates similarity and finally return similarity value from 0.0 to 1.0. In the experiment part of this paper, we visually presented matched nodes and unmatched nodes between two trees. By using this tree similarity algorithm, we can not only evaluate similarity between two specific programs or documents but also detect duplicated code.

A Study on Modern Applicability of Traditional Colored Thread Quilting Technique (전통 색실누비 기법의 현대적 활용에 관한 연구)

  • Lee, Mi Seok
    • Journal of the Korean Society of Costume
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    • v.65 no.2
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    • pp.92-104
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    • 2015
  • Colored thread quilting is sewed up padded with Han-Ji (한지, korean paper) string using colored thread. This showed up geometric pattern with repeated line of straight, diagonal, curve. According to geometric pattern, Colored thread quilting showed visual effects. The purpose of this study is to present manufacturing techniques, kinds, use, shape of traditional colored thread quilting. furthermore, This study has produced fashion items that can be used in modern life by using techniques of colored thread quilting. According to the fashion items, It present succession and utilization of techniques of colored thread quilting. This study was conducted in the following manner First, It studied traditional colored thread quilting techniques through the documents consideration, previous researches and by surveying antiquity in the museum. 2nd, It tried to make a reproduction about techniques of traditional colored thread quilting. 3rd, This study has selected and developed item and design of fashion items that can be used pragmatically in modern life by using techniques of colored thread quilting. And Fashion items that have been produced in this study is a total 10 kinds that was composed of Vest 4ea, Pendant & Brooch 6ea. Colored thread quilting is a unique technique of thread quilting that combines powerful practicality with decorativeness only in korea. These technique hope that it can developed more variety of items in modern life.

Against the Asymmetric CP- V2 Analysis of Old English

  • Yoon, Hee-Cheol
    • Korean Journal of English Language and Linguistics
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    • v.4 no.2
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    • pp.117-149
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    • 2004
  • The paper is to argue against the asymmetric CP-V2 analysis of Old English, according to which finite verbs invariably undergo movement into a clause-final T within subordinate clauses and reach the functional head C within main clauses. The asymmetric CP-V2 analysis, first of all, faces difficulty in explaining a wide range of post-verbal elements within subordinate clauses. To resolve the problem, the analysis has to abandon the obligatoriness of V-to-T movement or introduce various types of extraposition whose status is dubious as a legitimate syntactic operation. Obligatory V-to-T movement in Old English lacks conceptual justification as well. Crosslinguistic evidence reveals that morphological richness in verbal inflection cannot entail overt verb movement. Moreover, the operation is always string-vacuous under the asymmetric CP- V2 analysis and has no effect at the interfaces, in violation of the principle of economy. The distribution of Old English finite verbs in main clauses also undermines the asymmetric CP-V2 analysis. Conceptually speaking, a proper syntactic trigger cannot be confirmed to motivate obligatory verb movement to C. The operation not only gets little support from nominative Case marking, the distribution of expletives, or complementizer agreement but also requires the unconvincing stipulation that expletives as well as sentence-initial subjects result from string-vacuous topicalization. Finally, textual evidence testifies that Old English sometimes permits non-V2 ordering patterns, many of which remain unexplained under the asymmetric CP-V2 analysis.

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Learning of Adaptive Behavior of artificial Ant Using Classifier System (분류자 시스템을 이용한 인공개미의 적응행동의 학습)

  • 정치선;심귀보
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.10a
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    • pp.361-367
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    • 1998
  • The main two applications of the Genetic Algorithms(GA) are the optimization and the machine learning. Machine Learning has two objectives that make the complex system learn its environment and produce the proper output of a system. The machine learning using the Genetic Algorithms is called GA machine learning or genetic-based machine learning (GBML). The machine learning is different from the optimization problems in finding the rule set. In optimization problems, the population of GA should converge into the best individual because optimization problems, the population of GA should converge into the best individual because their objective is the production of the individual near the optimal solution. On the contrary, the machine learning systems need to find the set of cooperative rules. There are two methods in GBML, Michigan method and Pittsburgh method. The former is that each rule is expressed with a string, the latter is that the set of rules is coded into a string. Th classifier system of Holland is the representative model of the Michigan method. The classifier systems arrange the strength of classifiers of classifier list using the message list. In this method, the real time process and on-line learning is possible because a set of rule is adjusted on-line. A classifier system has three major components: Performance system, apportionment of credit system, rule discovery system. In this paper, we solve the food search problem with the learning and evolution of an artificial ant using the learning classifier system.

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Searching for Variants Using Trie-Index (트라이 인덱스를 이용한 이형태 검색)

  • Park, In-Cheol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.8
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    • pp.1986-1992
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    • 2009
  • A user often searches a data by inputting a variant such as the abbreviation or substring of a word, or a misspelled word. The simple approach to the searching for variants is to build a variants dictionary. However, it entails enormous cost and time and can not handle variants by misspelling. Approximate searching, searching by approximate string matching, is a good approach to the searching. A problem in the approach is that it cannot handle variants by abbreviations. This paper propose a method for searching various variants including abbreviations and misspelled words, by using the trie indexing. First, this paper shows a variant matching method with the calculation of path weighted-metric. In addition, it provides variant searching algorithm to reduce the search time.

Character String Detection using Character-Edge Map with Adaptive Character Size and Character String Orientation in Natural Images (자연영상에서 문자의 크기와 문자열의 방향에 적응적인 문자-에지 맵을 이용한 문자열 검출)

  • Park, Jong-Cheon;Hwang, Dong-Guk;Lee, Woo-Ram;Jun, Byoung-Min
    • Proceedings of the KAIS Fall Conference
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    • 2007.11a
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    • pp.262-265
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    • 2007
  • 이미지 데이터베이스 시스템에서 이미지에 포함된 문자정보를 기반으로 검색어를 사용한다면 검색의 정확도 높일 수 있다. 이미지에서 문자정보를 추출을 위한 전단계로서 문자열 영역 검출이 필수적인 과제가 된다. 그러므로 본 논문에서는 문자의 크기와 문자열의 방향에 적응적인 문자-에지 맵을 이용한 문자열 영역 검출 방법을 제안한다. 캐니-에지 검출기로 에지를 추출하고, 생성된 에지 이미지로 레이블 이미지를 얻고, 그 영역의 문자구조 특징을 분석하기 위해서 배열문법으로 문자-에지 맵에 적응적으로 분석한다. 문자-에지 맵의 분석결과로서 문자열 후보 영역을 얻고, 문자열 영역의 구조적인 특징을 이용하여 문자열 후보 영역을 검증함으로서 최종적인 문자열 영역을 검출한다. 제안한 방법은 다양한 종류의 자연영상을 대상으로 실험하였고, 자연영상에서 기울어진 문자열과 다양한 크기의 문자를 갖는 문자열 영역을 효과적으로 검출하였다.

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