• 제어로봇시스템학회논문지
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• 제13권9호
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• pp.868-874
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• 2007

This paper proposes an efficient partial matching system and representation by using a region-based method for 2D image, and we applied to an extraction of the ROI(Region of Interest) according to its matching score. The matching templates consist of the global pattern and the local one. The global pattern can make it by using region-based relation between center region and its rest regions in an object. And, the local pattern can be obtained appling to the same method as global, except relation between objects. As the templates can be normalized, we use this templates for extraction of ROI with invariant to size and position. And, our system operates only one try to match, due to normalizing of region size. To use our system for searching and examining if it's the ROI by evaluating the matching function, at first, we are searching to find candidate regions with the global template. Then, we try to find the ROI among the candidates, and it works this time by using the local template. We experimented to the binary and the color image respectively, they showed that the proposed system can be used efficiently for representing of the template and the useful applications, such as partially retrievals of 2D image.

• 한국컴퓨터정보학회논문지
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• 제8권4호
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• pp.87-91
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• 2003

본 논문에서는 현재 주차장에서 사용되는 입출 차량의 관리를 정기권 카드나 티켓발행기와 병행하여 사용될 수 있는 자동차 번호 인식 시스템을 개발하였다. 주차장은 차량의 흐름을 원활하고 신속하게 처리해야 하기 때문에 많은 자동차 번호 인식시스템을 도입했으나 운영 면에서 여러 가지 문제점을 가지고 있었다. 본 논문에서는 이러한 단점을 보완하기 위하여 기존의 시스템을 바탕으로 유동적인 시스템을 개발하였다. 자동차 번호 인식시스템은 주차장에 설치될 경우 99%의 성능을 가져야 하지만 날씨의 변화와 계절이 변동함에 따라 많은 영향을 받고 있다. 따라서 본 논문에서는 4계절과 날씨에 민감함을 고려하여 차량번호판 영역을 히스토그램 모폴로지를 사용하여 번호판 영역을 추출하고 신경망을 사용하여 숫자만을 인식하는 시스템을 개발하였다.

• 디지털산업정보학회논문지
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• 제8권1호
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• pp.171-181
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• 2012

This paper introduces the double-density discrete wavelet transform(DWT) using quincunx sampling, which is a DWT that combines the double-density DWT and quincunx sampling method, each of which has its own characteristics and advantages. The double-density DWT is an improvement upon the critically sampled DWT with important additional properties: Firstly, It employs one scaling function and two distinct wavelets, which are designed to be offset from one another by one half. Secondly, the double-density DWT is overcomplete by a factor of two, and Finally, it is nearly shift-invariant. In two dimensions, this transform outperforms the standard DWT in terms of denoising; however, there is room for improvement because not all of the wavelets are directional. That is, although the double-density DWT utilizes more wavelets, some lack a dominant spatial orientation, which prevents them from being able to isolate those directions. A solution to this problem is a quincunx sampling method. The quincunx lattice is a sampling method in image processing. It treats the different directions more homogeneously than the separable two dimensional schemes. Proposed wavelet transformation can generate sub-images of multiple degrees rotated versions. Therefore, This method services good performance in image processing fields.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1596-1600
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• 2000

We propose a novel adaptive feed forward controller (AFC) design method for rejecting the effect of micro actuator resonance in the design of dual-stage actuator servo systems for disk drives. Microactuator's resonance is one of important issues in dual-stage actuator servo, which varies up to ${\pm}10%$ per product and even during operation. We derive an adaptive algorithm for the proposed AFC design, which turns out to be identical to the delayed-x LMS algorithm which is a special form of the filtered-x LMS algorithm. In the algorithm, coefficients of the AFC are adapted by the residuals of constrained structure defined in such a way that the coefficients become time invariant. Contrary to the conventional AFC, it considers the phase delay of closed-loop transfer function at resonance frequency for system stability. We also apply an adaptive algorithm with frequency tracking capability. The frequency tracking algorithm is induced by the orthogonality of AFC coefficients. Computer simulations are carried out to demonstrate effect of the proposed AFCs.

• 천문학회보
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• 제42권1호
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• pp.52.2-53
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• 2017

We develop a methodology to use the redshift dependence of the galaxy 2-point correlation function (2pCF) as a probe of cosmological parameters. The positions of galaxies in comoving Cartesian space varies under different cosmological parameter choices, inducing a redshift-dependent scaling in the galaxy distribution. This geometrical distortion can be observed as a redshift-dependent rescaling in the measured 2pCF. The shape of the 2pCF exhibits a significant redshift evolution when the galaxy sample is analyzed under a cosmology differing from the true, simulated one. Other contributions, including the gravitational growth of structure, galaxy bias, and the redshift space distortions, do not produce large redshift evolution in the shape. We show that one can make use of this geometrical distortion to constrain the values of cosmological parameters governing the expansion history of the universe. This method could be applicable to future large scale structure surveys, especially photometric surveys such as DES, LSST, to derive tight cosmological constraints. This work is a continuation of our previous works as a strategy to constrain cosmological parameters using redshift-invariant physical quantities.

• 한국언론정보학보
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• 제48권
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• pp.191-210
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• 2009

본 연구에서는 뉴스 메시지의 프레임과 개인의 관여도가 과학기술 관련 위험인식에 미치는 영향을 알아보고자 하였다. 이를 위해 위험에 대한 낙관적 편견과 제3자 효과 이론을 이론적 근거로 하여 가설을 제시하고 실험을 통해 검증하고자 하였다. 실험에서는 피험자를 방사선 조사식품에 대한 고관여자와 저관여자 집단으로 구분하고 뉴스 메시지의 프레임에 따라 이들이 자신과 다른 사람들에 대한 위험인식 과정에서 어떠한 특징을 보이는가를 조사하였다. 연구결과, 부정프레임 기사를 접한 저관여자를 제외하면 실험조건 별 사회수준 위험인식은 상대적으로 유사한 것으로 나타났다. 반면 개인수준의 위험인식은 기사 프레임과 관여도에 따라 다르게 형성되었다. 본 연구에서는 이러한 두 수준의 위험인식을 실험조건 별로 비교하여 낙관적 편견이 나타나는 과정에 대한 이해를 시도하였다.

• 제어로봇시스템학회논문지
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• 제14권5호
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• pp.462-466
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• 2008

This paper proposes a stable gain scheduling method of linear time invariant controllers for tracking servo system. In order to read and write the data on the optical disc, the pick-up head should be moved to the exact track quickly and follow the track immediately. Two different controllers are used for each moving and track-following. In pull-in period, a transition period from moving to track-following, the head might slip and miss the target track. This brings on another searching process and increases the total time. One way to avoid slipping is to extend the bandwidth of the track-following controller. But, extending the bandwidth could degrade the following performance. More prevalent way is to use one more controller in this pull-in period and switch to the following controller. In general, however, switching or scheduling of stable controllers cannot guarantee the stability. This paper suggests an scheduling method guaranteeing the overall stability not only in a generalized form but also in special form for SISO system. The sufficient condition is derived from the fact that Q factor of a stable controller should be stay in $RH_{\infty}$ space. In the experiment, the proposed method shows better performance than the switching method such as shorter time and lower current consumption.

• 제어로봇시스템학회논문지
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• 제19권11호
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• pp.1022-1028
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• 2013

It is well knowns that based on the CSP (Common Spatial Pattern) algorithm, the linear projection of an EEG (Electroencephalography) signal can be made to spaces that optimize the discriminant between two patterns. Sharing disadvantages from linear time invariant systems, CSP suffers from the non-stationary nature of EEGs causing the performance of the classification in a BCI (Brain-Computer Interface) system to drop significantly when comparing the training data and test data. The author has suggested a simple idea based on the parallel model of CSP filters to improve the performance of BCI systems. The model was tested with a simple CSP algorithm (without any elaborate regularizing methods) and a perceptron learning algorithm as a classifier to determine the improvement of the system. The simulation showed that the parallel model could improve classification performance by over 10% compared to conventional CSP methods.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2411-2414
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• 2003

In this paper, we present a digital image authentication using semi-fragile watermarking techniques. The algorithm is robust to innocuous manipulations while detecting malicious manipulations. Specifically, the proposed method is designed for the purpose of the real time authentication of an image frame captured from a digital camera due to its easy H/W implementation, security and visible verification. To achieve the semi-fragile characteristics that survive a certain amount of compression, we employ the invariant property of DCT coefficients' quantization proposed by Lin and Chang [1]. The binary watermark bits are generated by exclusive ORing the binary logo with pseudo random binary sequences. Then watermark bits are embedded into the LSBs of pre-quantized DCT coefficients in the medium frequency range. Verification is carried out easily due to visually recognizable pattern of the logo extracted by exclusive ORing the LSBs of the embedded DCT coefficient with pseudo random number seeded by a secret key. By the experiment results, this method is not only robust to JPEG compression but also it detects powerfully alterations of the original image, such as the tempering of images.

• Smart Structures and Systems
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• 제3권4호
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• pp.423-437
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• 2007

The empirical mode decomposition (EMD) method is well-known for its ability to decompose a multi-component signal into a set of intrinsic mode functions (IMFs). The method uses a sifting process in which local extrema of a signal are identified and followed by a spline fitting approximation for decomposition. This method provides an effective and robust approach for decomposing nonlinear and non-stationary signals. On the other hand, the IMF components do not automatically guarantee a well-defined physical meaning hence it is necessary to validate the IMF components carefully prior to any further processing and interpretation. In this paper, an attempt to use the EMD method to identify properties of nonlinear elastic multi-degree-of-freedom structures is explored. It is first shown that the IMF components of the displacement and velocity responses of a nonlinear elastic structure are numerically close to the nonlinear normal mode (NNM) responses obtained from two-dimensional invariant manifolds. The IMF components can then be used in the context of the NNM method to estimate the properties of the nonlinear elastic structure. A two-degree-of-freedom shear-beam building model is used as an example to illustrate the proposed technique. Numerical results show that combining the EMD and the NNM method provides a possible means for obtaining nonlinear properties in a structure.