• International Journal of Control, Automation, and Systems
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• 제6권6호
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• pp.800-808
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• 2008

A fingerprint verification system based on a set of invariant moment features and a nonlinear Back Propagation Neural Network(BPNN) verifier is proposed. An image-based method with invariant moment features for fingerprint verification is used to overcome the demerits of traditional minutiae-based methods and other image-based methods. The proposed system contains two stages: an off-line stage for template processing and an on-line stage for testing with input fingerprints. The system preprocesses fingerprints and reliably detects a unique reference point to determine a Region-of-Interest(ROI). A total of four sets of seven invariant moment features are extracted from four partitioned sub-images of an ROI. Matching between the feature vectors of a test fingerprint and those of a template fingerprint in the database is evaluated by a nonlinear BPNN and its performance is compared with other methods in terms of absolute distance as a similarity measure. The experimental results show that the proposed method with BPNN matching has a higher matching accuracy, while the method with absolute distance has a faster matching speed. Comparison results with other famous methods also show that the proposed method outperforms them in verification accuracy.

• 한국정보통신학회논문지
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• 제10권1호
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• pp.104-110
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• 2006

고정도, 저주파용 데이터 변환기로 사용되어온 델타-시그마 변환기는 그 출력 단에 1 bit 혹은 multi-bit 양자화기(ADC)를 사용할 수 있다. 이 중 multi-bit 양자화기를 사용하는 경우 궤환회로에도 multi-bit DAC을 사용하여야 하며 시스템의 데이터 변환 정확도는 DAC의 비선형성에 직접적인 영향을 받는다. 이 영향을 최소화하여 델타-시그마 변환기의 변환 정확도를 높이기 위해서는 DAC에 사용되는 단위 데이터 변환소자 간의 오차가 시스템에 미치는 영향을 최소화 하여야한다. 이 과정 즉 Dynamic Element Matching을 위하여 제안된 4가지 방안(DER, CLA, ILA, DWA)을 비교 설명하였다. 그리고 각 방안을 사용하였을 때 시스템 출력의 잡음 특성을 비교 하였다. 이중 DWA(Data Weighted Averaging) 방안이 가장 우수한 출력 특성을 보였다.

• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.211-221
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• 1998

It is becoming apparent that stereo matching algorithms need much information from high level cognitive processes. Otherwise, conventional algorithms based on bottom-up control alone are susceptible to local minima. We introduce a system that consists of two levels. A lower level, using a usual matching method, is based upon the local neighborhood and a second level, that can integrate the partial information, is aimed at contextual matching. Conceptually, the introduction of bottom-up and top-down feedback loop to the usual matching algorithm improves the overall performance. For this purpose, we model the image attributes using a Markov random field (MRF) and thereupon derive a maximum a posteriori (MAP) estimate. The energy equation, corresponding to the estimate, efficiently represents the natural constraints such as occlusion and the partial informations from the other levels. In addition to recognition, we derive a training method that can determine the system informations from the other levels. In addition to recognition, we derive a training method that can determine the system parameters automatically. As an experiment, we test the algorithms using random dot stereograms (RDS) as well as natural scenes. It is proven that the overall recognition error is drastically reduced by the introduction of contextual matching.

• 한국도로학회논문집
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• 제17권5호
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• pp.75-82
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• 2015

PURPOSES : In link matching using vehicular trajectory in a car navigation system, it is technically difficult to match the location of the subject vehicle with a link on an electronic map in the vehicle on a grade separation highway segment consisting of an elevated highway and atgrade highway, because of the overlap of geometric lines of the two highways. This study was initiated to propose a link matching algorithm using the characteristics of vehicular movement of the subject vehicle. METHODS : The selected test site is the highway segment between Jeong-reung IC and Gil-eum IC where the Inner Circulation Road and Jeong-reung-ro run together. To evaluate the proposed algorithm, this study collected the raw packet data of vehicles that drove on the test site. In a simulation environment, link matching was performed using an existing algorithm as well as the proposed algorithm. RESULTS: It was clearly found that the characteristics of vehicular movements are different on the two highways. CONCLUSIONS: The proposed algorithm outperformed the existing algorithm.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.361-367
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• 2006

This paper describes a novel stereo vision based localization of free parking site, which recognizes the target position of automatic parking system. Pixel structure classification and feature based stereo matching extract the 3D information of parking site in real time. The pixel structure represents intensity configuration around a pixel and the feature based stereo matching uses step-by-step investigation strategy to reduce computational load. This paper considers only parking site divided by marking, which is generally drawn according to relevant standards. Parking site marking is separated by plane surface constraint and is transformed into bird's eye view, on which template matching is performed to determine the location of parking site. Obstacle depth map, which is generated from the disparity of adjacent vehicles, can be used as the guideline of template matching by limiting search range and orientation. Proposed method using both the obstacle depth map and the bird's eye view of parking site marking increases operation speed and robustness to visual noise by effectively limiting search range.

• 한국음향학회지
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• 제43권2호
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• pp.145-151
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• 2024

함정 선체부착형 수동소나체계는 최근 표적탐지성능을 향상시키고자 함내 진동유기 소음을 제거하려는 연구가 활발히 진행중이다. 본 연구진은 신호처리의 관점에서 음향센서와 진동센서가 설치된 복합센서를 이용한 음향-진동 정합기법을 개선책으로 제시한다. 본 논문에서는 정합기법의 이론적 배경에 대해 기술한 후, 그것이 다중물리 유한 요소해석 상에서 실현됨을 보였다. 나아가 정합기법을 센서 시스템에 적용할 시의 표적신호 수신감도 상승 및 진동유기 소음 제거 성능을 산출하였으며, 정합기법의 실용성과 향후 연구방향에 대해 논하였다.

• Radiation Oncology Journal
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• 제37권2호
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• pp.134-142
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• 2019

Purpose: The aim is to study the dependence of deformable based auto-segmentation of head and neck organs-at-risks (OAR) on anatomy matching for a single atlas based system and generate an acceptable set of contours. Methods: A sample of ten patients in neutral neck position and three atlas sets consisting of ten patients each in different head and neck positions were utilized to generate three scenarios representing poor, average and perfect anatomy matching respectively and auto-segmentation was carried out for each scenario. Brainstem, larynx, mandible, cervical oesophagus, oral cavity, pharyngeal muscles, parotids, spinal cord, and trachea were the structures selected for the study. Automatic and oncologist reference contours were compared using the dice similarity index (DSI), Hausdroff distance and variation in the centre of mass (COM). Results: The mean DSI scores for brainstem was good irrespective of the anatomy matching scenarios. The scores for mandible, oral cavity, larynx, parotids, spinal cord, and trachea were unacceptable with poor matching but improved with enhanced bony matching whereas cervical oesophagus and pharyngeal muscles had less than acceptable scores for even perfect matching scenario. HD value and variation in COM decreased with better matching for all the structures. Conclusion: Improved anatomy matching resulted in better segmentation. At least a similar setup can help generate an acceptable set of automatic contours in systems employing single atlas method. Automatic contours from average matching scenario were acceptable for most structures. Importance should be given to head and neck position during atlas generation for a single atlas based system.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2004년도 추계 종합학술대회 논문집
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• pp.265-268
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• 2004

현재 대부분의 정보검색시스템에서 사용되고 있는 키워드 매칭기법은 기하급수적으로 늘어나는 정보를 효과적으로 처리하기에는 부적합하다. 이러한 문제는 의미정보를 활용하여 해결할 수 있으며, 본 논문에서는 의미정보를 효과적으로 활용할 수 있는 한 방법을 제시한다. 본 논문에서 제안한 기법은 의미정보를 개념그래프를 이용하여 표현하고, 이를 정보검색에 활용한다. 구현된 시스템은 완전 매칭과 부분 매칭이 가능한 시스템이다. 부분 매칭은 구문적 부분 매칭과 의미적 부분 매칭 두 가지가 있다. 의미적 유사도는 온톨로지 내의 서브클래스 관계로 계산된다. 이러한 기법은 정보검색 뿐만 아니라 동적 하이퍼링크의 구현 등 다양한 분야에서 적용될 수 있다.

• 한국자동차공학회논문집
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• 제5권6호
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• pp.192-201
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• 1997

The feedback control scheme of the pressure control system of the rear wheel steering gear which has relatively large volume and sprung load was built up in order to improve th response characteristic of the system. The control algorithm chosen was a feedback compensator joined by a feedfoward compensator and the model matching method was used in the process of control system design. The structures and properties of the reference models were inspected and the parameters of the controller were decided. The improvement of the response characteristic of the pressure control valve by means of the feedback control is affirmed. Particularly, when the order of the system model is higher than the 2nd order, the effectiveness of the feedback control on the improvement of the response characteristic of the valve is distinct. And the convenience of the model matching method is the process of control system design is confirmed as well.

• 한국전자파학회논문지
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• 제21권5호
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• pp.519-527
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• 2010

본 연구에서는 가변 임피던스 정합 회로를 갖는 루프 안테나를 이용한 13.56 MHz 무선 전력 전송 시스템을 제안하였다. 일반적으로 무선 전력 전송 시스템은 공진기간의 이격 거리가 변함에 따라 결합계수가 변하게 되며, 이는 반사 임피던스에 의한 임피던스 부정합을 발생시킨다. 본 연구에서 제안한 방식은 varactor 다이오드를 갖는 가변 임피던스 정합 회로를 사용함으로써 루프 안테나 간의 이격 거리 변화에 따른 임피던스 부정합을 보상할 수 있다. 따라서, 안테나간의 거리가 가까워 결합계수가 큰 경우에도 우모드와 기모드의 발생을 최소화하여 중심 주파수의 변화 없이 최적의 전송 효율을 얻을 수 있다. 본 논문에서 제안한 방법의 유용성을 입증하기 위하여 13.56 MHz에서 동작하는 $30\;cm{\times}30\;cm$ 크기의 루프 안테나를 갖는 무선 전력 전송 시스템을 고정 임피던스 정합 회로와 가변 임피던스 정합 회로를 갖는 경우로 각각 설계하고, 거리에 따른 입력 임피던스, 입력 반사 계수 및 효율 변화를 측정하였다. 또한 가변 임피던스 정합 회로를 송신기와 수신기의 한 쪽에만 사용하는 경우와 양 쪽 모두에 사용하는 경우를 비교 측정하였다. 측정 결과, 고정 임피던스 정합 회로보다 가변 임피던스 정합 회로를 사용하는 것이 효율이 개선되며, 한 쪽에만 사용하는 경우보다 양 쪽 모두에 사용하는 것이 개선된 효율을 보임을 확인하였다.