• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.689-699
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• 2016

As the demand for LCD increases, the importance of inspection equipment for improving the efficiency of LCD production is continuously emphasized. The pattern inspection apparatus is one that detects minute defects of pattern quickly using optical equipment such as line scan camera. This pattern inspection apparatus makes a decision on whether a pixel is a defect or not using a single threshold value in order to meet constraint of real time inspection. However, a method that uses an adaptive thresholding scheme with different threshold values according to characteristics of each region in a pattern can greatly improve the performance of defect detection. To apply this adaptive thresholding scheme it has to be known that a certain pixel to be inspected belongs to which region. Therefore, this paper proposes a region matching algorithm that recognizes the region of each pixel to be inspected. The proposed algorithm is based on the pattern matching scheme with the consideration of real time constraint of machine vision and implemented through GPGPU in order to be applied to a practical system. Simulation results show that the proposed method not only satisfies the requirement for processing time of practical system but also improves the performance of defect detection.

• Journal of the Korea Society of Computer and Information
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• v.16 no.5
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• pp.13-22
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• 2011

Network Intrusion Detection Systems use regular expression to represent malicious packets and hardware-based pattern matching is required for fast deep packet inspection. Although hardware architectures for implementing constraint repetition operators such as {10} were recently proposed, they have some limitation. In this paper, we propose hardware architecture supporting constraint repetitions of general regular expression sub-patterns with lower logic complexity. The subpatterns supported by the proposed contraint repetition architecture include general regular expression patterns as well as a single character and fixed length patterns. With the proposed building block, we can implement more efficiently regular expression pattern matching hardwares.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.211-212
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• 2008

본 논문에서는 LCD 구동 모들 PCB의 기능 검사를 위한 자동 검사시스템인 EVT(Emulated Vision Tester)를 제안하고 구현하였다. 기존의 대표적인 자동검사 방법으로는 전기적 검사나 영상기반 검사방식이 있으나 전기적 검사만으로는 Timing이 주요한 변수가 되는 LED 장비에서는 검출할 수 없는 구동불량이 존재하며 영상기반 검사는 영상획득에 일관성이 결여되거나 Gray Scale의 구분이 불명확하며 검출결과의 재현성이 떨어진다. EVT 시스템은 Pattern Generator에서 인가된 입력 패턴 신호라 구동모듈을 통한 후 출력되는 디지털 신호를 직접 비교하여 패턴을 검사하고 아날로그 신호 (전압, 저항, 파형)의 이상 여부도 신속 정확하게 검사할 수 있는 H/W적인 방법이다. 높은 검출 신뢰도와 빠른 처리 속도 뿐만 아니라 간결한 시스템 구성으로 원가절감 실현 등 많은 장점을 가진다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.598-600
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• 2001

본 논문에서는 양상 뮤 논리를 위한 속성 명세 패턴 연구를 통해 시제 논리에 대한 패턴 기반의 단일한 프레임워크를 제시한다. 본 연구에서는 Dwyer의 속성 명세 패턴 분류를 상태(S)와 행동(A)으로 세분화하고 이를 다시 강함(A)와 약함(E)으로 다시 세분했다. 이러한 의미 기반의 계층적 패턴 분류 체계를 통해 양상 뮤 논리의 속성 명세 패턴을 분석했으며 실제 모형 검사기에서 사용된 예제들의 패턴 분류에 적용했다. 그 결과 기존의 분류 체계보다 더 정확한 분류가 가능했을 뿐만 아니라, 속성 명세의 작성 및 이해가 용이하였다.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.102-109
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• 2006

Several methods for PCB pattern inspection have been tried to detect fine detects in pad contours, but their low detection accuracy results from pattern variations originating from etching, printing and handling processes. The adaptive inspection algorithm has been newly proposed to extract minute defects based on movable segments. With gerber master images of PCB, vertex extractions of a pad boundary are made and then a lot of segments are constructed in master data. The pad boundary is composed of segment units. The proposed method moves these segments to optimal directions of a pad boundary and so adaptively matches segments to pad contours of inspected images, irrespectively of various pattern variations. It makes a fast, accurate and reliable inspection of PCB patterns. Its performances are also evaluated with several images.

• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.65-72
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• 2007

In this study, we used nondestructive test based on ultrasonic test as inspection method and compared backpropagation neural network(BPNN) with probabilistic neural network(PNN) as pattern recognition algorithm of weld flaws. For this purpose, variables are applied the same to two algorithms. Where, feature variables are zooming flaw signals of reflected whole signals from weld flaws in time domain. Through this process, we compared advantages/ disadvantages of two algorithms and confirmed application methods of two algorithms.

• The Mathematical Education
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• v.62 no.2
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• pp.175-194
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• 2023

Despite the importance of pattern learning for elementary school students, few studies have investigated in detail the understanding of patterns of lower-grade students. This study aimed to analyze the understanding of patterns of second-grade elementary school students. Since the patterns in the second grade are taught through the unit called Finding Rules, students' understanding of patterns was compared and contrasted before and after they learned the unit. To this end, a written instrument to measure students' understanding of patterns was developed on the basis of previous studies on pattern learning for lower-grade students. A total of 189 students were analyzed. As a result of the study, the overall correct answer rates in the post-test were higher in most items than those in the pre-test, illustrating the positive effect of the specific unit. However, students found it difficult to find rules in which two components would change simultaneously either in geometric or numeric patterns, find patterns that would be similar in structure, represent geometric patterns into numeric patterns, find empty terms in increasing patterns, and reason the specific terms in patterns that can be differently interpreted. Based on these research results, this study sheds light on students' understanding of patterns and suggests implications to improve their understanding.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.27-37
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• 2011

The IDS/IPS(Intrusion Detection/Prevention System) has been widely deployed to protect the internal network against internet attacks. Reducing the packet inspection time is one of the most important challenges of improving the performance of the IDS/IPS. Since the IDS/IPS needs to match multiple patterns for the incoming traffic, we may have to apply the multiple pattern matching schemes, some of which use finite automata, while the others use the shift table. In this paper, we first show that the performance of those schemes would degrade with various kinds of pattern sets and payload, and then propose a hybrid multiple pattern matching scheme which combines those two schemes. The proposed scheme is organized to guarantee an appropriate level of performance in any cases. The experimental results using real traffic show that the time required to do multiple pattern matching could be reduced effectively.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.153-154
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• 2007

본 논문에서는 반도체 패키징 기술의 일종인 TCP와 COF의 패턴 결함을 검출하는 영상 처리 알고리즘을 제안한다. 제안된 방법은 우선, TCP와 COF의 양품 패턴을 기준 영상으로 취득한다. 라인 스캐너에서 취득된 실시간 영상을 그레이로 변환한 후, 평균화 필터를 적용하고 임계값을 이용해서 검사하고자 하는 필름 영상의 이진화를 수행한다. 이진화 된 기준 영상과 검사하고자 하는 필름 영상을 이용해서 차영상을 구한 후에 라벨링을 하여 필름의 불량을 검출하게 된다. 제안된 패턴 매칭 방법이 TCP와 COF의 다양한 불량 항목 중에서 10여 가지의 불량 패턴을 대상으로 제안된 방법의 타당성을 검증하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.931-934
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• 2009

본 논문은 $24{\mu}m$ 이하의 미세 폭 및 $30{\mu}m$ 이하의 피치와 같이 미세 패턴을 가진 칩 온 필름(chip-on-film, COF)에 발생한 결함들을 자동으로 검출할 수 있는 시스템을 제안한다. 개발된 검출시스템은 미세 패턴의 COF에서 발생한 개방 (open), 단락 (hard short), mouse bite 및 near short (soft short)과 같은 다양한 결함들을 자동으로 빠르게 검출할 수 있는 기술이 적용되어 있다. 본 논문에서 제안하는 결함 검사 기술의 기본 원리는 미세 패턴내의 결함으로 인해 발생한 저항의 미세 변화를 고주파 공진기 (resonator)를 이용하여 측정 주파수에서 증폭시키고 증폭된 결함 신호와 결함이 없는 경우의 신호와의 전압차를 읽어서 0이 아니면 결함이 있음을 판단한다. 제안된 시스템은 미세 패턴 COF 검사 과정에서 결함들을 신속히 측정할 수 있으므로 불필요한 COF 복사를 위해 소요되는 경비를 줄일 수 있으리라 기대한다.