• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2003년도 춘계학술발표논문집 (상)
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• pp.691-694
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• 2003

게이트는 사람의 걷는 방법 혹은 그 특성을 나타내는 용어로써, 최근 컴퓨터 비젼 기술을 이용하여 개개인을 분별하기 위한 게이트 특징 정보를 추출하고자 하는 연구가 활발히 진행되고 있다. 그러나 영상을 기반으로 추출한 게이트 정보는 카메라의 시점에 종속적인 단점을 가지고 있다. 이러한 단점을 해결하기 위한 노력으로 3차원 정보를 획득하려는 연구가 진행되고 있으나 이는 카메라와 사람간의 거리, 카메라 파라미터 등 부가적인 정보를 필요로 한다. 본 논문에서는 영상내의 정보만을 이용하여, 카메라 시점에 종속적인 게이트 인식의 단점을 해결할 수 있는 방안을 제안한다. 먼저 실루엣 영상으로부터 걷는 방향을 찾아내고, 간단한 연산을 통해 평면 호모그래피를 추정한다. 추정된 호모그래피를 이용하여 측면 시점의 영상으로 재구성하면, 시점 변화에 비종속적인 게이트 정보를 추출할 수 있다. 본 논문에서 제안한 방법을 평가하기 위하여 실추엣 영상의 폭과 높이 변화를 비교하였다 실험을 통해 제안한 방법을 적용할 경우, 그렇지 않은 경우에 비하여 특징 변화가 적음을 확인하였고, 특히 보폭 통의 게이트 특징 정보가 일정한 값을 유지함을 볼 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.47-53
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• 2004

The paper shows that the combination of the hardware, NI PCI 6110E board and the software, Fourier and continuous wavelet transform(CWT) can be used to implement for extracting the important features of the real-time signal. The results confirmed that CWT produces the fast computation enough for the application of the real-time signal processing except the negligible time delay. In denoising case, because of the lack of translation invariance of wavelet basis, traditional wavelet thresholding leads to pseudo-Gibbs phenomena in the vicinity of discontinuities of signal. In this paper, in order to reduce the pseudo-Gibbs phenomena, wavelet coefficients are threshold and reconstruction algorithm is implement through shift-invariant gibbs free denoising algorithm based on wavelet transform footprint. The proposed algorithm can potentially be extended to more general signals like piecewise smooth signals and represents an effective solution to problems like signal denoising.

• 한국항공우주학회지
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• 제37권8호
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• pp.759-766
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• 2009

본 논문은 INS/vSLAM 통합 항법 시스템의 성능 향상을 위한 기초 연구로써, 비전 센서의 영상처리 성능을 향상을 위한 알고리즘 개발에 목표를 두고 있다. 비전센서의 영상처리알고리즘으로 SIFT 알고리즘을 사용하였으며, SIFT 알고리즘의 특징점 정합 성능을 개선하기 위해 특징점 정합 필터를 적용하였다. 본 논문에서 제안한 알고리즘을 이용하여 기존의 SIFT 알고리즘을 파라미터 조절한 경우보다 향상된 결과를 얻을 수 있었다. 차후 실시간 통합 항법 시스템에 적용하기 위해서 알고리즘의 속도를 향상시키는 작업이 필요하다.

• International Journal of Contents
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• 제13권4호
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• pp.70-79
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• 2017

Images are an important element in patents and many experts use images to analyze a patent or to check differences between patents. However, there is little research on image analysis for patents partly because image processing is an advanced technology and typically patent images consist of visual parts as well as of text and numbers. This study suggests two methods for using image processing; the Scale Invariant Feature Transform(SIFT) algorithm and Optical Character Recognition(OCR). The first method which works with SIFT uses image feature points. Through feature matching, it can be applied to calculate the similarity between documents containing these images. And in the second method, OCR is used to extract text from the images. By using numbers which are extracted from an image, it is possible to extract the corresponding related text within the text passages. Subsequently, document similarity can be calculated based on the extracted text. Through comparing the suggested methods and an existing method based only on text for calculating the similarity, the feasibility is achieved. Additionally, the correlation between both the similarity measures is low which shows that they capture different aspects of the patent content.

• 한국군사과학기술학회지
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• 제16권4호
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• pp.456-464
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• 2013

Passive sonar in submarine can detect the target in long range and can attack using it. There are many noises which can be received at passive sonar of submarine. When noise received in the sonar it make diverse interference pattern depend on the ocean ambient and movement scenario. Interference pattern can be explained by theory of waveguide invariant. In this paper, analyze the interference pattern according to the relative motions of surface ship and submarine. And analyze the occurrence reason of 2 kinds of interference patterns those are usually display on the submarine console. The results show that if relative speed of submarine and target increase then gradient of interference pattern will increase. And closest point approach of submarine and target decrease then gradient of interference pattern will increase. Bathtube pattern usually appear when target pass though close to submarine and Pinetree pattern appear target pass though above of submarine.

• 융합신호처리학회논문지
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• 제4권3호
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• pp.1-6
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• 2003

탱크나 경유자동차 등과 같이 지상에서 이동하는 차량들의 엔진소음은 광대역 특성을 갖고 또한 지형의 다양성 및 표적의 이동으로 인한 다양한 반사 등으로 변화가 심하기 때문에 탐지나 추적이 쉽지 않다 또한 전장 등과 같이 복잡한 환경에서는 배열안테나의 위치 선정 등의 어려움으로 앨리아싱이 일어날 수도 있다. 본 논문에서는 수동 배열 안테나의 성긴 배치로 인한 심각한 공간 앨리아싱 조건하에서 광대역 신호를 방사하는 이동체의 탐지 및 추적 문제에 대해서 연구하였다. 여기서 서브밴드 MUSIC 알고리즘에 근거한 고해상도의 방위각 추정 알고리즘을 개발하였다. 이 것은 공간 앨리아싱으로 인하여 표적의 방위각 추정 값이 변할 때에도 실제의 방위각을 추정할 수 있는 알고리즘이다 결과적으로 이 알고리즘이 성긴 안테나 배치로 인한 공간 앨리아싱 영향을 극복하고 위치 추정을 개선함을 보인다.

• East Asian Economic Review
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• 제18권1호
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• pp.3-27
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• 2014

This paper examines the effects of financial crises on the long memory volatility dependency of daily exchange returns focusing on the Asian crisis in 97-98 and the Global crisis in 08-09. By using the daily KRW-USD and JPY-USD exchange rates which have different trading regions and volumes, this paper first applies both the parametric FIGARCH model and the semi-parametric Local Whittle method to estimate the long memory volatility dependency of the daily returns and the temporally aggregated returns of the two exchange rates. Then it compares the effects of the two financial crises on the long memory volatility dependency of the daily returns. The estimation results reflect that the long memory volatility dependency of the KRW-USD is generally greater than that of the JPY-USD returns and the long memory dependency of the two returns appears to be invariant to temporal aggregation. And, the two financial crises appear to affect the volatility dynamics of all the returns by inducing greater long memory dependency in the volatility process of the exchange returns, but the degree of the effects of the two crises seems to be different on the exchange rates.

• 동력기계공학회지
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• 제2권1호
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• pp.67-72
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• 1998

In crane control system, it is required that the travelling time of crane must be reduced as much as possible and there is no the swing of load at the end and starting points. In this paper, we present a hybrid control method which includes two control methods of the optimal regulator and the velocity pattern control in order to realize high performance of the anti-sway. To implement the control algorithm, the dynamic equation is linearlized at an equilibrium point, so that the linear time invariant state equation can be obtained. A 1/10 sized model crane of the usual gantry cranes is made and used to show the applicability of the developed hybrid control method. The effectiveness of developed hybrid control method is proved by experimental results which show us good performance for anti-sway control comparing to conventional velocity pattern control. Practically, it is expected that the proposed control system will make an important contribution to the automatic crane control system of the industrial fields.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1993년도 추계학술대회논문집; 반도아카데미, 26 Nov. 1993
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• pp.77-83
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• 1993

In this paper, the dynamics of a 2-DOF not 1:1 resonant Hamiltonian system are studied. In the first part of the work, the behaviors of special periodic orbits called normal modes are examined by means of the harmonic balance method and their approximate stability ar analyzed by using the Synge's concept named stability in the kinematico-statical sense. Secondly, the global dynamics of the system for low and high energy are studied in terms of a perturbation analysis and Poincare' maps. In this part, one can see that the unstable normal mode generates chaotic motions resulting from the transverse intersections of the stable and unstable manifolds. Although there exist analytic methods for proving the existence of infinitely many periodic orbits, chaos, they cannot be applied in our case and thus, the Poincare' maps constructed by direct numerical integrations are utilized fot detecting chaotic motions. In the last part of the work, the existence of arbitrarily many periodic orbits of the system are proved by using a subharmonic Melnikov's method. We also study the possibility of the breakdown of invariant KAM tori only when h>h$_{0}$ (h$_{0}$:bifurcating energy) and investigate the generality of the destruction phenomena of the rational tori in the systems perturbed by stiffness and inertial coupling.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.213-231
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• 2014

Existing image search systems allow users to search images by keywords, or by example images through content-based image retrieval (CBIR). On the other hand, users might learn more relevant textual information about an image from its text captions or surrounding contexts within documents or Web pages. Without such contexts, it's difficult to extract semantic description directly from the image content. In this paper, we propose an annotation watermarking system for users to embed text descriptions, and retrieve more relevant textual information from similar images. First, tags associated with an image are converted by two-dimensional code and embedded into the image by discrete wavelet transform (DWT). Next, for images without annotations, similar images can be obtained by CBIR techniques and embedded annotations can be extracted. Specifically, we use global features such as color ratios and dominant sub-image colors for preliminary filtering. Then, local features such as Scale-Invariant Feature Transform (SIFT) descriptors are extracted for similarity matching. This design can achieve good effectiveness with reasonable processing time in practical systems. Our experimental results showed good accuracy in retrieving similar images and extracting relevant tags from similar images.