• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.407-414
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• 2015

Interest points are generally located at the pixels where height changes occur. So, interest points can be the significant pixels for DSM generation, and these have the important role to generate accurate and reliable matching results. Manual operation is widely used to extract the interest points and to match stereo satellite images using these for generating height information, but it causes economic and time consuming problems. Thus, a tie point extraction method using Harris-affine technique and SIFT(Scale Invariant Feature Transform) descriptors was suggested to analyze height information of buildings in this study. Interest points on buildings were extracted by Harris-affine technique, and tie points were collected efficiently by SIFT descriptors, which is invariant for scale. Searching window for each interest points was used, and direction of tie points pairs were considered for more efficient tie point extraction method. Tie point pairs estimated by proposed method was used to analyze height information of buildings. The result had RMSE values less than 2m comparing to the height information estimated by manual method.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1259-1268
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• 2004

To organize training in limited training area for an actuai combat, realistic training simulation plugged in by various battle conditions is essential. In this paper, we propose a virtual target overlay technique which does not use a virtual image, but Projects a virtual target on ground-based CCD image by appointed scenario for a realistic training simulation. In the proposed method, we create a realistic 3D model (for an instructor) by using high resolution Geographic Tag Image File Format(GeoTIFF) satellite image and Digital Terrain Elevation Data (DTED), and extract the road area from a given CCD image (for both an instructor and a trainee). Satellite images and ground-based sensor images have many differences in observation position, resolution, and scale, thus yielding many difficulties in feature-based matching. Hence, we propose a moving synchronization technique that projects the target on the sensor image according to the marked moving path on 3D satellite image by applying Thin-Plate Spline(TPS) interpolation function, which is an image warping function, on the two given sets of corresponding control point pair. To show the experimental result of the proposed method, we employed two Pentium4 1.8MHz personal computer systems equipped with 512MBs of RAM, and the satellite and sensor images of Daejoen area are also been utilized. The experimental result revealed the effective-ness of proposed algorithm.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.189-194
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• 2012

The consequences of microbe-mineral interaction often resulted in the chemical, structural modification, or both in the biologically induced mineral. It is inevitable to utilize the high powered resolution of electron microscopy to investigate the mechanism of biogenic mineral transformation at nano-scale. The applications of transmission electron microscopy (TEM) capable of electron energy loss spectroscopy (EELS) to the study of microbe-mineral interaction were demonstrated for two examples: 1) biogenic illite formation associated with structural Fe(III) reduction in nontronite by Fereducing bacteria; 2) siderite phase formation induced by microbial Fe(III) reduction in magnetite. In particular, quantification of the changes in Fe-oxidation state at nanoscale is essential to understand the dynamic modification of minerals resulted from microbial Fe reduction. The procedure of EELS acquisition and advantages of EELS techniques were discussed.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1347-1358
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• 2008

A blind video watermarking scheme for providing safety, authenticity, and copyright protection is proposed in this paper, which is robust to MPEG-4 SVC and multimedia transcoding. In proposed method, embedding and detecting of watermark is performed based on base layer with considering spatial SVC. To be robust from temporal SVC, our method embeds repeatedly a permutated character with ordering number per one frame. Also for robustness from multimedia transcoding and FGS, the method is embedded watermark in low middle frequency of each frame adaptively based on DCT in ROI. Through experimental results, invisibility of the watermark is confirmed and robustness of the watermark against the spatial SVC, temporal SVC, FGS and video transcoding between MPEG-2 and MPEG-4 SVC is also verified.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.387-394
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• 2006

In this study, the effect of using a neutral beam formed by low-angle forward reflection of a reactive ion beam on aspect-ratio-dependent etching (ARDE) has been investigated. When a SF6 Inductively Coupled Plasma and $SF_6$ ion beam etching are used to etch poly-Si, ARDE is observed and the etching of poly-Si on $SiO_2$ shows a higher ARDE effect than the etching of poly-Si on Si. However, by using neutral beam etching with neutral beam directionality higher than 70 %, ARDE during poly-Si etching by $SF_6$ can be effectively removed, regardless of the sample conditions. The mechanism for the removal of ARDE via a directional neutral beam has been demonstrated through a computer simulation of different nanoscale features by using the two-dimensional XOOPIC code and the TRIM code.

• The Journal of the Acoustical Society of Korea
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• v.22 no.4
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• pp.299-307
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• 2003

There have been many studies on speaker normalization which aims to minimize the effects of speaker's vocal tract length on the recognition performance of the speaker independent speech recognition system. In this paper, we propose a simple vector quantizer based linear warping speaker normalization method based on the observation that the vector quantizer can be successfully used for speaker verification. For this purpose, we firstly generate an optimal codebook which will be used as the basis of the speaker normalization, and then the warping factor of the unknown speaker will be extracted by comparing the feature vectors and the codebook. Finally, the extracted warping factor is used to linearly warp the Mel scale filter bank adopted in the course of MFCC calculation. To test the performance of the proposed method, a series of recognition experiments are conducted on discrete HMM with thirteen mono-syllabic Korean number utterances. The results showed that about 29% of word error rate can be reduced, and that the proposed warping factor extraction method is useful due to its simplicity compared to other line search warping methods.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.23-30
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• 2017

Since shape, size and distribution of particles in particulate composites have spreaded characteristics, properties of particulate composites have variation and also system behavior using particulate composites have variation. However, it is difficult to consider spreaded characteristic of particles so that a system behavior is analysed using homogeneous techniques or using microstructure in local areas. In this study, for considering random variation of particles, RMDFs(random morphology description functions) are used to generate random microstructure and relationship between the number of gaussian functions and spreaded characteristic of particles was analysed using the geometrical moment of area. Also, multi-scale analysis was carried out for cantilever beam with full-random microstructure to study behavior of particulate composites structure. As a result, it is defined that spreaded characteristic of particles and the variation of deflections of cantilever beam are decreased as the number of Gaussian functions(N) is increased and converges at N=200.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.347-351
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• 2020

A material changes its physical and chemical properties through the interaction with radiation and also the neutrons, which is electronically neutral so that the penetration depth is relatively deeper than that of other radioactive way including alpha or beta ray. Therefore, the radiation damage by neutron irradiation has been intensively investigated for a long time with respect to the safety of nuclear power plants. The damage induced by neutron irradiation begins with the creation of point defects in atomic scale in the unit of picoseconds, and their progress pattern can be characterized by microstructural defects, such as dislocation loops and voids. Their morphological characteristics affect the properties of neutron-irradiated materials, therefore, it is very important to predict the microstructure at a given neutron irradiation condition. This paper briefly reviews the evolution of radiation damage induced by neutron irradiation and introduces a phase-field model that can be widely used in predicting the microstructure evolution of irradiated materials.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.10
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• pp.794-801
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• 2017

In this paper, we proposed airborne target recognition using multi-channel combining method in DTV-based passive radar. By combining multi-channel signals, we obtained the HRRP with sufficient range resolution. HRRP was obtained by AR method or zero-padding. From the obtained HRRP, we extracted scattering centers by CLEAN algorithm using the gradient descent. We extracted feature vectors and performed target recognition after training neural network using the extracted feature vectors. To verify performance of proposed methods, we assumed frequency bands of three broadcasting transmitters operated in Korea(Mt. Gwan-ak, Mt. Yong-moon, Kyeon-wol-ak) and used full scale 3D CAD model of four targets. Also we compared the target recognition performance of the proposed method with that of using only single-channel of three broadcasting transmitters. As a result, proposed methods showed better performance than using only single-channel at three broadcasting transmitters.

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.81-85
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• 2002

In this paper, a new fragi1e watermarking algorithm for medical images is proposed. It makes possible to resolve the security and forgery problem of the medical images. In the proposed algorithm. the singularity which represents the inherent characteristic of the medical image is extracted and used as watermark. To extract the singularity point. we adopted Mallat wavelet transform because it can describe the edge of image exactly. Mallat wavelet transform produces horizontal and vertical subbands of the same resolution with the original image. The magnitude and phase components of the edge are obtained using these subbands. Based on the magnitude and phase components. LMM which will be used as watermark is determined. As LMM is the inherent singularity of image, if any forgery is applied to medical image, LMM of original and forged image are different each other Detecting the changes of LMM for the two images makes it possible whether any image is undergone forgery or not From the experimental results, we conformed that the proposed algorithm detects the forged area of the image very well.