• 전자공학회논문지B
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• 제28B권12호
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• pp.51-58
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• 1991

In this paper, we propose a multiresolution edge detection method which selects the edge detection window size and scale automatically by using the local variance information as an edgeness measure of a region. The mode of the local variance distribution which is calculated over the (2p + 1) x (2p + 1) windows is used to determine the resolution of the given pixel and the edge operator with different scale can be applied to the pixel depending on its resolution. The combination of the resolution determination scheme with the conventional Canny and LOG edge detectors gives the proposed multiresolution edge detection schemes. The effectness of the proposed schemes is shown via computer simulation.

• Tuberculosis and Respiratory Diseases
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• 제58권6호
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• pp.543-553
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• 2005

Radiological analysis of chest lesions detected on chest radiographs or CT scans begins with their classification into parenchymal, pleural, or extrapleural lesions according to their presumed origin. The mediastinum is divided anatomically into the anterior, middle, and posterior mediastinal compartments, and localizing a mediastinal mass to one of these divisions can facilitate their differential diagnosis. A differential diagnosis of a mediastinal mass is usually based on a number of findings, including its location; the structure from which it is arising; whether it is single, multifocal (involving several different areas or lymph node groups), or diffuse; its size and shape; its attenuation (fatty, fluid, soft-tissue, or a combination of these); the presence of calcification along with its characteristics and amount; and its opacification following the administration of contrast agents.

• The Journal of Advanced Prosthodontics
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• 제4권4호
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• pp.235-238
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• 2012

Facial prosthesis is generally considered over surgical reconstruction to restore function and appearance in patients with facial defects that resulted from cancer resection. Retention of the prosthesis is challenging due to its size and weight. Retention can be achieved by using medical grade adhesives, resilient attachments, clips and osseointegrated implants. It can also be connected to obturator by magnets. This clinical report highlights the rehabilitation of a lateral midfacial defect with a two piece prosthesis that included an extra oral facial prosthesis and an intraoral obturator with the use of magnets.

• Journal of Communications and Networks
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• 제9권2호
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• pp.141-149
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• 2007

Multiple-input multiple-output (MIMO) transmit pre-coding/beamforming can significantly improve system spectral efficiency. However, several obstacles prevent precoding from wide deployment in early wireless networks: The significant feedback overhead, performance degradation due to feedback delay, and the large storage requirement at the mobile devices. In this paper, we propose a precoding method that addresses these issues. In this approach, only 3 or 6 bits feedback is needed to select a precoding matrix from a codebook. There are fifteen codebooks, each corresponding to a unique combination of antenna configuration (up to 4 antennas) and codebook size. Small codebooks are prestored and large codebooks are efficiently computed from the prestored codebook, modified Hochwald method and Householder reflection. Finally, the feedback delay is compensated by channel prediction. The scheme is validated by simulations and we have observed significant gains comparing to space-time coding and antenna selection. This solution was adopted as a part of the IEEE 802.16e specification in 2005.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2222-2224
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• 2001

This paper presents the implementation of an efficient car tracking system based on Inverted DGPS (IDGPS) using mobile phone and internet for data communication link. The IDGPS technique, which may provide the same level of accuracy as DGPS, is subject to degradation in real time applications when transmission time delays occur in the communication links. Therefore, an effective communication system is the key element for successful application of the IDGPS. The combination of internet and mobile phones provides a high data rate, unlimited communication packet size, flexible data structure, and wide coverage without additional communication devices. An implementation of such a data link system is described. Field test results are included to evaluate the performance of the proposed system.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.424-428
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• 2016

This paper presents the kinematics of a walking robot leg based on Jansen mechanism. By using simple mathematics, all trajectories of walking robot leg links can be calculated. A foot point trajectory is used to evaluate the performance of a walking robot leg. Trial and Error method is used to find a best combination of link lengths under certain restrictions. All simulations are performed by Matlab. Ground score, drag score, step size, foot lift, instant speed, and average speed of foot point trajectories are used for selecting the best one.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.625-626
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• 2006

In the present study, the focus is on the synthesis of nanosized WC powder by the chemical vapor condensation proces. The synthesized W-C system powder by the CVC process shows W2C, W, WO3 phases and can not shows WC phase. After recarburization heat treatment under mixture gas atmosphere of argon and hydrogen gases, the synthesized W-C system powder fully transformed to the pure WC. The synthesized WC powder after recarburization heat treatment has an average particle size of 20 nm. The nano-sized WC powder can be prepared by the combination of the CVC process and heat treatment methods.

• 소성∙가공
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• 제11권6호
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• pp.538-546
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• 2002

Hot deformation behavior of Udiment720Li was characterized by compression tests in the temperature range of 10$25^{\circ}C$ to 115$0^{\circ}C$ and the strain rate range of $0.0005 s^{-1};to;5 s^{-1}$. The combination of dynamic material model (DMM) and Ziegler's instability criterion was applied to predict an optimum condition and unstable regions for hot forming. A dynamic recrystallization model coupled with FEM results was used to interpret the evolution of microstructures. In order to verify the reliability of the present coupled model, isothermal forging was performed in the temperature range 1050~115$0^{\circ}C$ at strain rates of $0.05 s^{-1};and;0.005 s^{-1}$. The present model was successfully applied to the hot forming process of Udimet720Li.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.570-573
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• 2004

Conventional methods for reducing vibration in engineering designs may be undesirable in conditions where size or weight must be minimized, or where complex vibration spectra exist. Some alloys with a combination of high damping capacity and good mechanical properties can provide attractive techanical and economical solutions to problems involving seismic, shock and vibration isolation. In this paper, it showed the noise and vibration characteristic was compared conventional rail joint to improved rail joint(damping alloy) for reducing noise and vibration. Its applicability to rail joint is discussed.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.117-120
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• 1996

To enhance cellulose hydrolysis f Humicola insolens cellulase (HIC) was empolyed with immobilized glucose isomerase(IGI). Optimun pH and temperature for HIC were 6.5 and 55$^{\circ}C$, respectively, whereas those for IGI were 7.0 and 60$^{\circ}C$, respectively. Optimun loading size of IGI was 200mg(130 untis) with 15units of HIC. Reaction conditions were determined to be as follows: 55$^{\circ}C$,pH 6.5, HIC 15 units and IGI 130 units. After 24h hydrolysis, more than 65% of avicel was converted to glucose and fructose; in contrast, the conversion ratio of control was 40%.