• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.1056-1064
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• 2010

This paper presents the approximate analysis method for the symmetric transmission line crossing the aperture in an backplane. The method of moments is used to determine the aperture impedance for the construction of the equivalent transmission line that the aperture impedance apply to the transmission line as the shunt impedance. As the results, the insertion loss increases at the specific frequency range for the impedance matching. In the case of the mismatching, we are confirmed to the insertion gain at the specific frequency. Also the horizontal length of the aperture affects to the transmission line better than vertical length. The measurement of the insertion loss is performed to verify the theoretical analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.1929-1939
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• 1999

This paper presents a neural network approach, which was named PRONET, to 3D object recognition and pose calculation. 3D objects are represented using a set of centroidal profile patterns that describe the boundary of the 2D views taken from evenly distributed view points. PRONET consists of the training stage and the execution stage. In the training stage, a three-layer feed-forward neural network is trained with the centroidal profile patterns using an error back-propagation method. In the execution stage, by matching a centroidal profile pattern of the given image with the best fitting centroidal profile pattern using the neural network, the identity and approximate orientation of the real object, such as a workpiece in arbitrary pose, are obtained. In the matching procedure, line-to-line correspondence between image features and 3D CAD features are also obtained. An iterative model posing method then calculates the more exact pose of the object based on initial orientation and correspondence.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.4
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• pp.289-294
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• 2011

Digital redesign is yet another efficient tool to convert a pre-designed analog controller into a sampled-data one to maintain the analog closed-loop performance in the sense of state matching. A rising difficulty in developing a digital redesign technique for trackers with time-varying references is the unavailability of a closed-form discrete-time model of a system, even if it is linear time-invariant. A way to resolve this is to approximate the time-varying reference as a piecewise constant one, which deteriorates the state matching performance. Another remedy may be to decrease a sampling period, which however could numerically destabilize the optimization-based digital redesign condition. In this paper, we develop a digital redesign condition for time-varying trackers by approximating the time-varying reference through a triangular hold and by introducing delta-operated discrete-time models. It is shown that the digitally redesigned sampled-data tracker recovers the performance of the pre-designed analog tracker under a fast sampling limit. Simulation results on the formation flying of satellites convincingly show the effectiveness of the development.

• Journal of KIISE:Software and Applications
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• v.37 no.10
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• pp.788-801
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• 2010

Advancing of mobile device is remarkable, so the research on mobile input device is getting more important issue. There are lots of input devices such as keypad, QWERTY keypad, touch and speech recognizer, but they are not as convenient as typical keyboard-based desktop input devices so input strings usually contain many typing errors. These input errors are not trouble with communication among person, but it has very critical problem with searching in database, such as dictionary and address book, we can not obtain correct results. Especially, Hangeul has more than 10,000 different characters because one Hangeul character is made by combination of consonants and vowels, frequency of error is higher than English. Generally, suffix tree is the most widely used data structure to deal with errors of query, but it is not enough for variety errors. In this paper, we propose fast approximate Korean word searching system, which allows variety typing errors. This system includes several algorithms for applying general approximate string searching to Hangeul. And we present profanity filters by using proposed system. This system filters over than 90% of coined profanities.

• Proceedings of the Korean Association for Survey Research Conference
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• 2006.12a
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• pp.67-83
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• 2006

In successive sampling on two occasions the problem of estimating a finite population quantile has been considered. The theory developed aims at providing the optimum estimates by combining (i) three double sampling estimators viz. ratio-type, product-type and regression-type, from the matched portion of the sample and (ii) a simple quantile based on a random sample from the unmatched portion of the sample on the second occasion. The approximate variance formulae of the suggested estimators have been obtained. Optimal matching fraction is discussed. A simulation study is carried out in order to compare the three estimators and direct estimator. It is found that the performance of the regression-type estimator is the best among all the estimators discussed here.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.415-417
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• 2001

인터넷의 성장에 따라, 많은 웹사이트가 생기고, 더 많은 정보들이 웹사이트에 등록되었다. 웹사이트에서 등록되는 정보가 많을수록, 사용자가 원하는 정보를 얻기가 쉽지 않다. 따라서, 사용자가 찾는 정보를 쉽게 찾을 수 있도록, 웹사이트 내에 전문(full-text) 검색엔진을 도입하기도 한다. 본 논문에서는 사용자가 자연어를 이용한 대화를 통해 웹사이트 내의 정보를 습득할 수 있도록 하는 대화형 도우미 에이전트를 위하여 한글 전처리 방법과 근사패턴매칭기법을 제안한다. 사용자가 문장을 입력하면, 동의어처리와 형태소 분석을 통해 사용자의 문장을 분석하고, 이미 작성되어 있는 지식과의 매칭을 통해 사용자에게 알맞은 대답을 제시한다. 지식은 XML 형식으로 저장되며, 사용자가 입력한 문장과 아주 똑같지 않더라도, 어느 정도의 유사도를 가지고 대답을 이끌어 낼수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.1861-1873
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• 1996

This paper describes the content-based image retrieval system that is implemented to retrieve images using constituent rate of lines and Bezier curves. We proposed the line and Bezier curve extraction algorithm which extracts lines and curve that are fitted on the contour information of images. For this extration, it was necessary to remove internal area of the proprocessed object within images and to approximate its contour to polygon, and proposed retrevial algorithm which gets the simularity using the consitituent rate of lines and curves and perform the simularity matching.

• Journal of the Korean Statistical Society
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• v.36 no.4
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• pp.543-556
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• 2007

In successive sampling on two occasions the problem of estimating a finite population quantile has been considered. The theory developed aims at providing the optimum estimates by combining (i) three double sampling estimators viz. ratio-type, product-type and regression-type, from the matched portion of the sample and (ii) a simple quantile based on a random sample from the unmatched portion of the sample on the second occasion. The approximate variance formulae of the suggested estimators have been obtained. Optimal matching fraction is discussed. A simulation study is carried out in order to compare the three estimators and direct estimator. It is found that the performance of the regression-type estimator is the best among all the estimators discussed here.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.5
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• pp.83-86
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• 1985

An alternative technique (or the numerical solution of Fredholm integral equations of second kind is presented. The approximate solution is obtained by fitting the data in mixed form at knots in the region of the problem. To decrease the error in the numerical solution, cubic B-spline functions which are twice continuously differentiable at knots are employed as basis function. For a given example, the results of this technique are compared with those of Moment method employing pulse functions for basis function and delta functions for test function and found to br in good agreement.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.969-970
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• 2006

This paper develops a recognition system of assembly parts using a hardware independent image module. Using a shared memory, the image module consists of the image acquiring process and the image processing process. We preprocess an acquisition image from the module, approximate the image edges to an ellipse, and then recognize an assembly part by matching the ellipse to a model base one.