• Bulletin of the Korean Mathematical Society
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• v.53 no.5
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• pp.1439-1446
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• 2016

The execution complexities of the major time memory data tradeoff methods are analyzed in this paper. The multi-target tradeoffs covered are the classical Hellman, distinguished point, and fuzzy rainbow methods, both in their non-perfect and perfect table versions for the latter two methods. We show that their computational complexities are identical to those of the corresponding single-target methods executed under certain matching parameters and conclude that the perfect table fuzzy rainbow tradeoff method is most preferable.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.554-557
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• 2002

This paper describes power potential field method for the collision-free path planning of stereo-vision based mobile robot. Area based stereo matching is performed for obstacle detection in uncertain environment. The repulsive potential is constructed by distributing source points discretely and evenly on the boundaries of obstacles and superposing the power potential which is defined so that the source potential will have more influence on the robot than the sink potential when the robot is near to source point. The mobile robot approaches the goal point by moving the robot directly in negative gradient direction of the main potential. We have investigated the possibility of power potential method for the collision-free path planning of mobile robot through various experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5674-5691
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• 2016

Fast IDentity Online(FIDO) supports biometric authentications in an online environment without transmitting biometric templates over the network. For a given FIDO client, the "Fuzzy Vault" securely stores biometric templates, houses additional biometric templates, and unlocks private keys via biometrics. The Fuzzy Vault has been extensively researched and some vulnerabilities have been discovered, such as brute force, correlation, and key inversions attacks. In this paper, we propose a simple fingerprint Fuzzy Vault for FIDO clients. By using the FIDO feature, a simple minutiae alignment, and point-to-point matching, our Fuzzy Vault provides a secure algorithm to combat a variety of attacks, such as brute force, correlation, and key inversions. Using a case study, we verified our Fuzzy Vault by using a publicly available fingerprint database. The results of our experiments show that the Genuine Acceptance Rate and the False Acceptance Rate range from 48.89% to 80% and from 0.02% to 0%, respectively. In addition, our Fuzzy Vault, compared to existing similar technologies, needed fewer attempts.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.250-253
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• 2009

고해상도 컬러 위성 영상 촬영을 위한 다중분광 센서를 탑재한 위성의 영상은, 탑재체에 장착된 센서의 위치에 따라, 동일 지역에 대해 센서 간의 촬영시각의 차이가 발생한다. 만약 이동하는 구름이 촬영될 경우, 센서별 촬영 영상간에는 구름과 지상과의 상대적 위치가 달라진다. 고해상도 컬러 위성 영상을 생성하기 위해, 영상 정합(image registration) 기법이 사용되는 데, 일반적인 영상 정합 알고리즘은 촬영 영상에서의 특징점(feature point)이 움직이지 않는 것을 전제로 수행한다. 그 결과 이동하는 구름 경계부에서 정합점(matching point)이 추출될 경우, 지상 영역에서의 정합품질이 좋지 않다. 따라서, 본 연구에서는 구름 경계부에서 정합점이 추출되지 않는 알고리즘을 제안하였다. 실험 영상으로 구름이 존재하는 아리랑2호 영상을 사용하였고, 제안된 영상 정합 알고리즘은 지상 영역에서의 정합 품질이 높였음을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.967-973
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• 1997

In this paper, the designed and fabrication of a K-band push-push oscillator using miniaturized hairpin resonator have been presented. One experimenal oscillator has been designed and fabricated for K-band point-to-point operation. the miniaturized harpin resonator has been analyzed theoretically and simulated by MPIE(Mixed Potential Integral Equation) method. With this results, the analysis of hairpin resonator which coupled microstrip line has been carried out with transmission-mode using this results. an optimized output matching network for the suppression of the fundamental and the 3rd order harmonic was acquired by using a nonlinear analysis method. The fabricated oscillator shows the output power of -2.28dBm, the fundamental frequency suppression of -19dBc, the 3rd order harmonic suppressionof -24dBc and 0.33 percent effiiency at 22.8GHz. The experimental outputs are in good agreement with the theoretical and simulated results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2663-2678
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• 2012

Due to sharp depth transition, big holes may be found in the novel view that is synthesized by depth-image-based rendering (DIBR). A hole-filling method based on disparity map is proposed. One important aspect of the method is that the disparity map of destination image is used for hole-filling, instead of the depth image of reference image. Firstly, the big hole detection based on disparity map is conducted, and the start point and the end point of the hole are recorded. Then foreground pixels and background pixels are distinguished for hole-dilating according to disparity map, so that areas with matching errors can be determined and eliminated. In addition, parallaxes of pixels in the area with holes and matching errors are changed to new values. Finally, holes are filled with background pixels from reference image according to these new parallaxes. Experimental results show that the quality of the new view after hole-filling is quite well; and geometric distortions are avoided in destination image, in contrast to the virtual view generated by depth-smoothing methods and image inpainting methods. Moreover, this method is easy for hardware implementation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.153-158
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• 2016

In this paper, TE(transverse electric) scattering problems by a conductive strip grating between grounded double dielectric layer are analyzed by applying the PMM(point matching method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the conductive boundary condition is applied to analysis of the conductive strip. The numerical results for normalized reflected power are analyzed by according as the width and spacing of conductive strip, the relative permittivity and thickness of the double dielectric layers, and incident angles. The most normalized reflected powers of the sharp variations in minimum values are scattered in direction of the other angles except incident angle. The numerical results for the presented structure of this paper having a grounded double dielectric layer are shown in good agreement compared to those of the existing papers.

• The Journal of Advanced Prosthodontics
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• v.12 no.3
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• pp.173-180
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• 2020

PURPOSE. This study compared digital (reference point matching) and replica methods for measuring marginal and internal fit of full coverage restorations. MATERIALS AND METHODS. A maxillary left first molar typodent was fixed on to an aluminum base and prepared to receive all-ceramic full coverage restoration. The model was scanned with an intraoral scanner (CEREC Omnicam, Sirona, York, PA, USA). Twelve crowns were fabricated from lithium disilicate blocks (IPS emax CAD, Ivoclar Vivadent) and then crystalized. Marginal and internal fit of each restoration was measured by two examiners using replica and a new digital three-dimensional technique. Reliability between the two methods and two examiners was assessed by correlation and Cronbach's Alpha coefficient (P<.05). A Bland-Altman assessment for agreement was used to compare the two methods. RESULTS. Bland-Altman assessment showed that the mean of difference for marginal, absolute marginal, and axial gap was respectively -1.04 ㎛, -41.9 ㎛, and -29.53 ㎛ with limit of agreement (LOA) between -37.26 to 35.18 ㎛ for marginal, -105.85 to 22.05 ㎛ for absolute marginal and -80.52 to 22.02 ㎛ for axial gap. Positive correlation for repeatability (P<.05) in determining marginal and internal gaps by the two examiners in both techniques was revealed. Reliability of both techniques in all sites of measurements was at least good (0.8 ≤ α < 0.9). CONCLUSION. Both measuring techniques appeared highly reliable for evaluating fit of fixed dental restorations, while reference point matching provided higher values in axial and absolute marginal gap assessment.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.127-137
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• 2018

Recently, UAVs and Drones have been used for various applications. In particular, in the field of surveying, there are studies on the technology for monitoring the terrain based on the high resolution image data obtained by using the UAV-equipped digital camera or various sensors, or for generating high resolution orthoimage, DSM, and DEM. In this study, we analyzed the accuracy of GCP(Ground control point) matching using UAV and VRS-GPS. First, we used VRS-GPS to pre-empt the ground reference point, and then imaged at a base altitude of 150m using UAV. To obtain DSM and orthographic images of 646 images, RMSE was analyzed using pix4d mapper version As a result, even if the number of GCP matches is more than five, the error range of the national basic map(scale : 1/5,000) production work regulations is observed, and it is judged that the digital map revision and gauging work can be utilized sufficiently.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.73-79
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• 2018

In this paper, TM(transverse magnetic) scattering problems by a conductive strip grating between a double dielectric layer are analyzed by applying the PMM(point matching method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the conductive boundary condition is applied to analysis of the conductive strip. The most normalized reflected powers of the sharp variations in minimum values are scattered in direction of the other angles except incident angle. Generally, in the case of numerical analysis except for reflection and transmission power in free space, as the dielectric constants of the double dielectric layer increases, the reflected power increases and the transmitted power decreases relatively, respectively. The numerical results for the presented structure of this paper having a grounded double dielectric layer are shown in good agreement compared to those of the existing papers.