• Korean Journal of Optics and Photonics
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• v.12 no.1
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• pp.55-60
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• 2001

We propose a method to extract features optically from the input pattern by use of an array of Hough transfOllli filters. Here the subparts of the input pattern are Hough-transformed by. their cOlTesponding elements of the filter array independently and simultaneously. Compared with the conventional method, in which the whole input pattern is Hough-transformed by a single optical filter, the proposed method not only provides the improved optical transform results when the input pattern becomes complex but also extracts the approximate position information of the line segment features. To show the feasibility of this approach, we fabricated a $5\times5$ filter array and performed preliminary experiments.iments.

• Korean Journal of Optics and Photonics
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• v.8 no.5
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• pp.403-409
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• 1997

We proposed a system that can perform pattern recognition based on parrallel optical feature extraction and performed experiments on this. The feature to be extracted are both 6 simple line orientations and two eigenvectors of the covariance matrix of the patterns that cannot be distinguished with the line orientation features alone. Our system consists of a feature-extraction part and a pattern-recognition part. The former that extracts the features in parallel with the multiplexed Vander Lugt filters was implemented optically, while the latter that performs the pattern recognition by the use of the extracted features was implemented in a computer. In the pattern recognition part, two methods are tested;one is to use an artificial neural network, which is trained to recognize the features directly, the other is to count the numbers of specific features simply and then to compare them with the stored reference feature numbers. We report the preliminary experimental results tested for 15 alpabet patterns with only straight line segments.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.3
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• pp.19-28
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• 1990

The main purpose of this paper is to present both fundamental and some higher natural frequencies of catenary arcs. The differential equations governing planar free vibrations for these arcs are derived, in which the rotatory inertia is included, as non-dimensional forms and solved numerically to obtain frequencies and mode shapes. The hinged-hinged and clamped-clamped end constraints are applied in numerical examples. The lowest four natural frequencies are reported as the functions of non -dimensional system parameters; the slenderness ratio and the rise to span length ratio. The effects of rotatory inertia on natural frequencies are reported and some typical mode shapes are also presented.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.485-494
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• 1992

This study dealt with the concentration of heavy metals in mussels, Mylitus edulis and oysters, Crassostrea gigas, in different habitats around the Korean coastal waters during 1985-1989. The high levels of heavy metal concentration in two bivalves were found at Station 1, 2, 5, 23 and 25, while the low levels were found at stations in Chinhae Bay. Oysters were more effective bioaccumulators of Cu, Zn and Hg than mussels showing the ratios of 16:1 for Cu, 1.63:1 for Cd, 1.36:1 for Pb, 7.61:1 for Zn and 2.08:1 for Hg. The larger mussels were, the higher the concentrations of five metals.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.249-249
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• 2011

투명전도성산화물(transparent conducting oxides, TCOs) 박막은 전기 전도성과 광투과성이 우수하여 유기발광다이오드(organic light-emitting diode, OLED), 태양전지(solar cell), 발광다이오드(LED) 등의 광전자 소자에 널리 응용되고 있다. 특히 LED에서 p-GaN층에서 전류가 층안에서 충분하게 확산되지 않기 때문에, TCO는 균일하게 전류를 흘려보내기 위해서 전류확산층(current spreading layer)으로 사용된다. 그 중 널리 쓰이는 산화인듐주석(indium tin oxide, ITO)은 고가의 indium가격과 인체에 유해한 독성 등이 문제점으로 지적되고 있다. 따라서 indium의 함량을 저감하거나 함유하지 않은 새로운 조성의 친환경적 대체 TCO 개발에 대한 연구가 많이 진행되고 있다. 이러한 반도체 재료 중 하나인 AZO (Al-doped zinc oxide, Al2O3 : 2wt.%)는 3.3 eV의 넓은 에너지 밴드갭을 가지며, 가시광선 및 근적외선 파장영역에서 높은 투과율을 나타낸다. 따라서 본 연구에서는 GaN기반 LED 응용을 위한 전류확산층으로 ITO 대신 AZO의 특성을 연구하였다. 박막 증착율이 높고, 제작과정의 조정이 용이한 RF magnetron 스퍼터를 이용하여 glass기판 위에 AZO, Ni/AZO, NiOx/AZO를 증착하였다. 이어서 $N_2$ 분위기에서 다양한 온도 조건에서 열처리(rapid thermal annealing, RTA)하여 전기적 광학적 특성에 대하여 비교 분석하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.161-169
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• 2004

This paper deals with system identification of a three-story building model with active mass damper (MID) for the controller design. Observer Kalman filter identification (OKID) technique is applied to find the relationship between the experimental results of the input and output. The inputs to the building model with MID are ground accelerations and motor command signal, which are, respectively, simulated earthquake and equivalent control force. The outputs are each floor acceleration and MID acceleration. The MID controller is designed based on the experimentally identified building system. Finally it is shown that experimental results agree accurately with simulated results.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.10
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• pp.48-58
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• 1998

We present a method that can recognize face images using independent component analysis that is used mainly for blind sources separation in signal processing. We assumed that a face image can be expressed as the sum of a set of statistically independent feature images, which was obtained by using independent component analysis. Face recognition was peformed by projecting the input image to the feature image space and then by comparing its projection components with those of stored reference images. We carried out face recognition experiments with a database that consists of various varied face images (total 400 varied facial images collected from 10 per person) and compared the performance of our method with that of the eigenface method based on principal component analysis. The presented method gave better results of recognition rate than the eigenface method did, and showed robustness to the random noise added in the input facial images.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6B
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• pp.349-354
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• 2005

Several IP autoconfiguration techniques for MANET have been proposed by this time. But most of them concentrate on dealing with address duplication, so they have problems with latency and inefficient address space utilization. In this paper, we proposed a new IP autoconfiguration technique, namely Relational MANET Autoconfiguration Protocol(RMAP). This technique distributes IP addresses effectively by exchanging messages and recovers IP addresses by applying parent-child relationship. Simulation experiments are conducted to demonstrate the enhancement of the proposed algorithm over other known algorithms regarding latency, uniform distribution, and IP address recovery ratio.

• Journal of Intelligence and Information Systems
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• v.1 no.1
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• pp.1-22
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• 1995

본 연구에서 퍼지인식도(Fuzzy Cognitive Map) 개념을 기초로 하여 (1) 특정 문제영역에 대한 전문가의 인과관계 지식(causal knowledge)을 추출하는 알고리즘을 제시하고, (2) 이 알고리즘에 기초하여 작성된 해당 문제영역에 대한 여러 전문가들의 인과관계 지식을 계층별로 분해하여, (3) 해당 계층간의 양방향 추론이 가능한 추론메카니즘을 제시하고자 한다. 특정 문제영역에 있어서의 인과관계 지식이란 해당 문제를 구성하는 여러 개념간에 존재하는 인과관계를 표현한 지식을 의미한다. 이러한 인과관계 지식은 기존의 IF-THEN 형태의 규칙과는 달리 행렬형태로 표현되기 때문에 수학적인 연산이 가능하다. 특정 문제영역에 대한 전문가의 인과관계 지식을 추출하는 알고리즘은 집합연산에 의거하여 개발되었으며, 특히 상반된 의견을 보이는 전문가들의 의견을 통합하여 하나의 통합된 인과관계 지식베이스를 구축하는데 유용하다. 그러나, 주어진 문제가 복잡하여 다양한 개념들이 수반되면, 자연히 인과관계 지식베이스의 규모도 커지게 되므로 이를 다루는데 비효율성이 개재되기 마련이다. 따라서 이러한 비효율성을 해소하기 위하여 주어진 문제를 여러계측(Hierarchy)으로 분해하여, 해당 계층별로 인과관계 지식베이스를 구축하고 각 계층별 인과관계 지식베이스를 연결하여 추론하는 메카니즘을 개발하면 효과적인 추론이 가능하다. 이러한 계층별 분해는 행렬의 분해와 같은 개념으로도 이해될 수 있다는 특징이 있어 그 연산이 간단명료하다는 장점이 있다. 이와같이 분해된 인과관계 지식베이스는 계층간의 추론메카니즘을 통하여 서로 연결된다. 이를 위하여 본 연구에서는 상향 또는 하향방식이 추론이 가능한 양방향 추론방식을 제시하여 주식시장에서의 투자분석 문제에 적용하여 그 효율성을 검증하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.7
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• pp.696-708
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• 1992

In this study, we have several objectives. First, In spite of a fixed bandwidth waste of reservation channel, we maximize the efficiency of transmission channel by the multiple access algorithm that performs channel reservation and data transmission independently, eliminating the frame structure of transmission channel and reserving it by the slot unit . Second, In order to improve the entire system performance, we accommodate the variation of traffic at each earth station more effectively, and accomplish the stable delay characteristics and the equlity of service #or users. For this purpose, we design the satellite channel that consists of reservation channel and transmission channel which are logically separate and operate Independently. We also design a demand assignment multiple access algorithm based on the satellite channel structure.