• The Korean Journal of Nuclear Medicine
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• v.39 no.3
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• pp.174-181
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• 2005

Purpose: Reduction of respiratory motion artifacts in PET images was studied using respiratory-gated PET (RGPET) with moving phantom. Especially a method of generating simulated helical CT images from 4D-CT datasets was developed and applied to a respiratory specific RGPET images for more accurate attenuation correction. Materials and Methods: Using a motion phantom with periodicity of 6 seconds and linear motion amplitude of 26 mm, PET/CT (Discovery ST: GEMS) scans with and without respiratory gating were obtained for one syringe and two vials with each volume of 3, 10, and 30 ml respectively. RPM (Real-Time Position Management, Varian) was used for tracking motion during PET/CT scanning. Ten datasets of RGPET and 4D-CT corresponding to every 10% phase intervals were acquired. from the positions, sizes, and uptake values of each subject on the resultant phase specific PET and CT datasets, the correlations between motion artifacts in PET and CT images and the size of motion relative to the size of subject were analyzed. Results: The center positions of three vials in RGPET and 4D-CT agree well with the actual position within the estimated error. However, volumes of subjects in non-gated PET images increase proportional to relative motion size and were overestimated as much as 250% when the motion amplitude was increased two times larger than the size of the subject. On the contrary, the corresponding maximal uptake value was reduced to about 50%. Conclusion: RGPET is demonstrated to remove respiratory motion artifacts in PET imaging, and moreover, more precise image fusion and more accurate attenuation correction is possible by combining with 4D-CT.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.6
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• pp.22-34
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• 2010

Existing image scalers generally adopt simple interpolation methods such as bilinear method to take cost-benefit, or highly complex architectures to achieve high quality resulting images. However, demands for a low power, low cost, and high performance image scaler become more important because of emerging high quality mobile contents. In this paper we propose the novel low power hardware architecture for a high quality raster scan image scaler. The proposed scaler architecture enhances the existing cubic interpolation look-up table architecture by reducing and optimizing memory access and hardware components. The input data buffer of existing image scaler is replaced with line memories to reduce the number of memory access that is critical to power consumption. The cubic interpolation formula used in existing look-up table architecture is also rearranged to reduce the number of the multipliers and look-up table size. Finally we analyze the optimized parameter sets of look-up table, which is a trade-off between quality of result image and hardware size.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.65-73
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• 2007

This paper introduces design-for-test (DFT) techniques for low-cost system-on-chip (SoC) test. We present a Scan-Test method that controls IEEE 1500 wrapper thorough IEEE 1149.1 SoC TAP (Test Access Port) and design an at-speed test clock generator for delay fault test. Test cost can be reduced by using small number of test interface pins and on-chip test clock generator because we can use low-price automated test equipments (ATE). Experimental results evaluate the efficiency of the proposed method and show that the delay fault test of different cores running at different clocks test can be simultaneously achieved.

• Journal of the Korea Convergence Society
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• v.8 no.2
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• pp.9-14
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• 2017

A fingerprint is unique to each person and can be represented as a digital form. As the fingerprint is the part of human body, fingerprint recognition is much more easy to use and secure rather than using password or resident card for user authentication. In addition, as the newly released smart phones have built-in camera and fingerprint sensors, the demand for biometric authentication is increasing rapidly. But, the drawback is that the fingerprint can be counterfeited easily and if it's exposed to the hacker, it cannot be reused. Thus, the original fingerprint template should be transformed for registration and authentication purposes. Existing transformation functions use passcode to transform the original template to the cancelable form. Additional module is needed to input the passcode, so it requires more cost and lowers the usability. In this paper, we propose biometric authentication scheme that is economic and easy to use. The proposed scheme is consisted of cancelable biometric template creation, registration and user authentication protocols, and can control several security levels by configuring the number of fingerprints and scan times. We also analyzed that our scheme is secure against the brute-force attack and the active attacks.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.10
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• pp.1077-1083
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• 2009

To reject the Doppler frequency spectrum dispersion of clutter caused by high-speed antenna rotation of MTI radar system due to terrain characteristics, signal processing parameters(MTI filter constant, M/N detector ration, K-factor and offset of CFAR) are adjusted for the optimal elimination of the ground clutter. For this investigation, logging equipment is designed and utilized for the collection of classified ground clutter data. Test case is devised through Matlab simulation for the classified analysis and optimization of clutter rejection. Then indoor radar test and outside test in accordance with terrain characteristics are repeatedly performed for the verification of the test. This whole process is through the evolutional development model and repeated for the optimization. Final result is that ground-clutter rejection capability is 5.6 times(7.5 dB) better than that of existing radar system.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.2
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• pp.169-176
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• 2001

In modern industry, the accuracy and the sulfate-finish requirements for machined parts have been becoming ever more stringent. In addition, the measurement and understanding of surface topography is rapidly attracting the attention of the physicist and chemist as well as the engineer. Optical measuring method is used in vibration measurement, crack and defect detection with the advent of opto-mechatronics, and it is expected to play an important role in surface topography. In this study, the principle of confocal microscope is described, and the advanced 3-D surface measuring system that has better performance than the traditional confocal microscope is developed. Suitable fixtures arc developed and integrated with the computer system for generating 3-D surface and form data. Software for data acquisition and analysis of various parameters in surface geometrical features has been developed.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.99-99
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• 2012

소비자의 기호가 다양화되면서 다품종 소량생산에 따른 대량 맞춤화에 대한 관심이 높아지고 있으며, 1990년대 후반부터 급격히 확산되고 있는 인터넷의 발달 및 디지털 기기의 확산에 따라 인터넷을 기반으로 한 전자상거래 환경에서의 대량 맞춤화 프로세스는 최근 의류 분야에서 주요한 경향으로 받아들여지고 있다. 대량 맞춤화 의류 제품의 수요는 인터넷 등 IT 기술의 발달과 맞물려 최근 개인의 특성과 취향을 고려한 인터넷 맞춤서비스를 기반으로 증가추세에 있으며, CAD 등의 테크놀러지의 활용을 통하여 디자인, 패턴제작, 재단 등의 자동 시스템을 도입함으로써 그 영역을 확장하고 있다. 이에 발맞추어 국내에서는 '디지털 패션 시스템'을 통해 3차원 바디 스캔, 3차원 컴퓨터 그래픽스, 3차원 Simulation, DID, DTP, 맞춤주문형 제품의 대량 생산기술 등의 단위 기술이 기업단위로 활용되는 등 가상현실을 이용한 3차원 가상쇼핑 등을 포함하는 기술로서 차세대 섬유패션 산업의 창출에 기여하고 있다. 그 중, 디지털 텍스타일 프린팅은 디자인에서부터 날염까지 전체 공정을 컴퓨터로 처리하여 기존의 복잡한 날염 공정을 단축하여 다품종 소량생산이 가능한 날염 방식으로, 대량 맞춤형 프로세스를 지원하며, 프로슈머(prosumer)로서의 소비자가 직접 참여하여 그들의 욕구를 최대화 할 수 있는 소비자 만족을 극대화 시킬 수 있는 대량 맞춤화 프로세스 중 하나의 단계로 소비자의 수요 반영하는 요소로 작용하고 있다. 즉, 디지털 패션 시스템에서의 디지털 텍스타일 프린팅은 대량 맞춤형 의류 제품에 있어 소비자 만족도와 직결되는 요인으로 분석된다. 따라서, 본 연구에서는 디지털 패션 시스템 기반의 대량맞춤형 섬유제품 및 디지털 텍스타일 프린팅 적용 섬유제품에 대한 기초 평가 문항을 제시하고, 소비자 태도를 분석하여 제시하였다. 또한, 분석된 기초 소비자 태도를 반영하여, 디지털 패션 시스템 기반의 디지털 텍스타일 프린팅(Digital Textile Printing) 의류 제품의 선호도, 인지도, 수요도 및 구입의향을 분석하여 최종적으로 디지털 패션 시스템에 적용된 디지털 텍스타일 프린팅 의류 제품의 수요 경향을 제시하였다.

• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.393-407
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• 2020

In order to reduce the threat by illegal unmanned aerial vehicles, a tracking system based on sound was implemented. There are three main points to the drone acoustic tracking method. First, it scans the space through variable beam formation to find a sound source and records the sound using a microphone array. Second, it classifies it into a hidden Markov model (HMM) to find out whether the sound source exists or not, and finally, the sound source is In the case of a drone, a sound source recorded and stored as a tracking reference signal based on an adaptive beam pattern is used. The simulation was performed in both the ideal condition without background noise and interference sound and the non-ideal condition with background noise and interference sound, and evaluated the tracking performance of illegal drones. The drone tracking system designed the criteria for determining the presence or absence of a drone according to the improvement of the search distance performance according to the microphone array performance and the degree of sound pattern matching, and reflected in the design of the speech reading circuit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1225-1233
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• 2008

In this paper, the 2D/3D converting algorithm is proposed. The single frame of 2D image is used fur the real-time processing of the proposed algorithm. The proposed algorithm creates a 3D image with the depth map by using the vertical position information of a object in a single frame. In order to real-time processing and improve the hardware complexity, it performs the generation of a depth map using the image sampling, the object segmentation with the luminance standardization and the boundary scan. It might be suitable to a still image and a moving image, and it can provide a good 3D effect on a image such as a long distance image, a landscape, or a panorama photo because it uses a vertical position information. The proposed algorithm can adapt a 3D effect to a image without the restrictions of the direction, velocity or scene change of an object. It has been evaluated with the visual test and the comparing to the MTD(Modified Time Difference) method using the APD(Absolute Parallax Difference).

• Journal of Biomedical Engineering Research
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• v.10 no.3
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• pp.253-260
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• 1989

The time domain methods of estimating the attenuation coefficient are generally based on the analysis of statisical properties of the reflected echoes form an attenuating medium. Hence, it is often required to have a large number of data samples in order to obtain a statistically stable estimation result. In the attenuation estimation problem, this means that many different speckle patterns are required in the spatial resolution volume of an attenLlation image. In this paper, by using the fact that the speckle pattern Is sensitive to the point spread function of the ultrasound beam, we suggest a method to generate the statiscally uncorrelated or slightly correlated data samples in a given region by rotating a linear transducer and carrying out lateral scans for all rotating angles. This technique is applied to the entropy method for attenuation estimation proposed recently by the authors where the performance is verified by experiments using a tissue equivalent phantom.