• The Journal of the Acoustical Society of Korea
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• v.30 no.5
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• pp.239-248
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• 2011

In order to improve the quality of strain images in medical ultrasound imaging, displacements need to be accurately estimated. In this paper, in order to apply one-dimensional displacement estimation methods to two-dimensional motion estimation, the axial and lateral displacements are separately estimated. In order to estimate lateral displacements, one-dimensional signals aligned in the lateral direction are converted to analytic signals, which are then crosscorrelated. Strain images are produced by first compensating two-dimensional displacements for lateral motion with lateral motion displacement estimates obtained from the proposed lateral displacement estimation algorithm and then estimating axial displacements. Both phantom and human data experiments show that the proposed method provides better signal-to-noise ratio and contrast-to-noise ratio characteristics than a conventional strain imaging method that utilizes axial displacement estimates only.

• Journal of the Korean Society of Radiology
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• v.8 no.1
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• pp.1-10
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• 2014

The bi-plane cerebrovascular angiography radiation is done the radiation exposure at the forward and lateral direction as opposed to the one of the source. So, the exposure dose of radiation workers increases further. Therefore, the medical diagnostic radiation workers as well as patients is interested to ways to reduce the dose. The exposure dose of cerebral angiography and interventional radiology must be considered the primary radiation of X-ray tube directly, scattered primary radiation between lateral tube and lateral detector and relatively small secondary scatter radiation in the walls of room. The aim of study is that the exposure dose of primary and scatter radiation reduce as much as possible to install protection device of lateral protection than common shielding of table and ceiling. As a result, the dose of fluoroscopy was reduced approximately 3.64 times the gonads, thyroid approximately 3.13 times, 4.42 times around eyes. And the dose of DSA was reduced approximately 4.98 times the gonads, thyroid approximately 3.00 times, 1.67 times around eyes. Consequently, medical practitioners can be helpful for radiation dose-exposure for the lateral protection of bi-plane cerebrovascular angiography more than the common shield method in cerebrovascular angiography and interventional radiological procedures.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.425-431
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• 2019

The Study In order to obtain images of overlap of the two iron cores in the spinal cord simple x-ray scan after surgery of patients with ulcer lateral sclerosis and a fractured backbone, the researcher conducted a subjective evaluation on five radiographers of the university hospital's imaging department for more than 10 years. The results of the experiment showed that the lateral shot of lateral scoliosis of the spinal cord was taken with the middle face of the IR plane, and then the X-ray tube angle was taken vertically with the vertical spinal column fan-tom position, resulting in two overlapping images and high scores in the subjective evaluation. In addition, lateral shots of the lumbar dislocation fractured lumbar vertebrae were taken with the forehead aligned with the center of the IR plane and then with the X-ray angle perpendicular to the fourth waistline and the angle of the spinal cord perpendicular to the fourth waistline, the image of the two iron cores could be obtained from the radiographer.

• Korean Journal of Optics and Photonics
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• v.7 no.4
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• pp.375-385
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• 1996

Recently interest in the fabrication of LD operated by low current is gradually increasing as fabrication techniques of MQW-LD are progressed. In this viewpoint, theoretical estimation for decreasing the amount of threshold current will be helpful to design and make LD in case that active layer of conventional bulk type RWG-LD structure is replaced with MQW structure. Therefore, the optimum design condition of RWG MQW-LD was obtained from theoretical analysis in order to operate in the weakly index-guided LD and low threshold current. The lateral effective index step has been obtained in RWG MQW-LD structure. Waveguide mechanism including this index step has been investigated by solving the carrier diffusion equation and lateral wave equation. From these theoretical results, the optimum design condition of RWG MQW-LD have been suggested.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.53-60
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• 2020

The purpose of this paper is to evaluate the image of the Styrofoam Wedge that can minimize the position change by supporting the wrist during the True PA and lateral examination of the wrist. In 50 people, the gap between the distal radius joint facet and the wrist bone was measured after the wrist True PA and lateral images were obtained using a general examination(vertical), tube angle(vertical:10°, lateral:20°) and Styrofoam Wedge(vertical). When joint spacing was measured in the True PA and lateral images of the wrist, general examination(5.54mm, 9.42mm), tube angle(2.05mm, 5.07mm) and Styrofoam Wedge(1.79mm, 5.46mm) were shown to be small. The smaller the joint spacing, the easier it is to observe that is open. Therefore, True PA and lateral imaging of the wrist Styrofoam Wedge can reduce the distortion of the image and thus acquire images of high diagnostic value. In addition, it may be possible to reduce the deviation caused by the change of patient's position during re-projection.

• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.83-90
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• 1999

In this paper, we studied resolution to the FBP and BFP image reconstruction algorithms for ultrasonic diffraction tomography. In order to analyze the resolution to the tomographic images which can be reconstructed from the modified FBP image reconstruction algorithm by using fixed coordinate system and BFP image reconstruction algorithm which is suitable for plane structure object, we derived ambiguity functions to these algorithms and then analyzed lateral and depth resolution through simulation respectively. Simulation results show that the lateral and depth resolution to the FBP image reconstruction algorithm and the BFP image reconstruction algorithm was determined 0.27 λ, 0.70 λ and 0.39 λ, 0.98 λ at the 3dB respectively. These results imply that modified FBP and BFP image reconstruction algorithms for diffraction tomography is useful in the tomographic image reconstruction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.257-257
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• 2003

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.06a
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• pp.246-250
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• 1996

• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.88-89
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• 1999

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.8 s.338
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• pp.41-46
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• 2005

Microstrip open-end and linear resonator are analyzed by method of moment (MoM) taking the entire-domain current distribution, found in literature, along the transverse direction of microstrip line. A transverse correlation function which incorporates permittivity, thickness and width of the line is derived. Numerical examples are investigated and compared with the available other data and methods in order to give the validity of the proposed method. It is found that the proposed method can generate more accurate results than the conventional methods.