• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.82-98
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• 2019

The importance of spatial information is rapidly rising. In particular, 3D spatial information construction and modeling for Real World Objects, such as smart cities and digital twins, has become an important core technology. The constructed 3D spatial information is used in various fields such as land management, landscape analysis, environment and welfare service. Three-dimensional modeling with image has the hig visibility and reality of objects by generating texturing. However, some texturing might have occlusion area inevitably generated due to physical deposits such as roadside trees, adjacent objects, vehicles, banners, etc. at the time of acquiring image Such occlusion area is a major cause of the deterioration of reality and accuracy of the constructed 3D modeling. Various studies have been conducted to solve the occlusion area. Recently the researches of deep learning algorithm have been conducted for detecting and resolving the occlusion area. For deep learning algorithm, sufficient training data is required, and the collected training data quality directly affects the performance and the result of the deep learning. Therefore, this study analyzed the ability of detecting the occlusion area of the image using various image quality to verify the performance and the result of deep learning according to the quality of the learning data. An image containing an object that causes occlusion is generated for each artificial and quantified image quality and applied to the implemented deep learning algorithm. The study found that the image quality for adjusting brightness was lower at 0.56 detection ratio for brighter images and that the image quality for pixel size and artificial noise control decreased rapidly from images adjusted from the main image to the middle level. In the F-measure performance evaluation method, the change in noise-controlled image resolution was the highest at 0.53 points. The ability to detect occlusion zones by image quality will be used as a valuable criterion for actual application of deep learning in the future. In the acquiring image, it is expected to contribute a lot to the practical application of deep learning by providing a certain level of image acquisition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.76-84
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• 2012

In this paper, two kinds of E-plane microstrip-to-waveguide transitions are optimally designed and fabricated for combining output power from multiple small-power amplifiers in a WR-28 waveguide because conventional K connectors cause unnecessary insertion loss and adaptor loss. The transition design is based on target specifications such as a center frequency of 35 GHz, bandwidth of ${\pm}500MHz$, 0.1 dB insertion loss and 20 dB return loss. Performance variation caused by mechanical tolerance and assembly deviation is fully evaluated by three dimensional electromagnetic simulation. The fabricated back-to-back transitions with 16 mm and 26.57 mm interstage microstrip lines show insertion loss per transition of ~0.1 dB at 35 GHz and average 0.2 dB over full Ka band. Also the back-to-back transition shows return loss greater than 15 dB, which implies that the transition itself has return loss better than 20 dB.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.3 s.345
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• pp.48-58
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• 2006

This paper presents 8x8 two dimensional DCT/IDCT processor of adder-based distributed arithmetic architecture without applying ROM units in conventional memories. To reduce hardware cost in the coefficient matrix of DCT and IDCT, an odd part of the coefficient matrix was shared. The proposed architecture uses only 29 adders to compute coefficient operation in the 2-D DCT/IDCT processor, while 1-D DCT processor consists of 18 adders to compute coefficient operation. This architecture reduced 48.6% more than the number of adders in 8x8 1-D DCT NEDA architecture. Also, this paper proposed a form of new transpose network which is different from the conventional transpose memory block. The proposed transpose network block uses 64 registers with reduction of 18% more than the number of transistors in conventional memory architecture. Also, to improve throughput, eight input data receive eight pixels in every clock cycle and accordingly eight pixels are produced at the outputs.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.5
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• pp.529-545
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• 2012

Three-dimensional (3D) finite element analyses have been performed to study the behaviour of a single pile to open face tunnelling in stiff clay. Several key factors such as tunnelling-induced ground and pile settlement, and shear transfer mechanism have been studied in detail. Tunnelling resulted in the development of pile settlement larger than the Greenfield soil surface settlement. In addition, due to changes in the shear transfer between the pile and the soil next to the pile with tunnel advancement, axial force distributions along the pile change drastically. The apparent allowable pile capacity was reduced up to about 30% due to the development of tunnelling-induced pile head settlement. The skin friction on the pile was increased with tunnel advancement associated with the changes of soil stresses and ground deformation and hence axial pile force distribution was reduced. Maximum tunnelling-induced tensile force on the pile was about 21% of the designed pile capacity. The zone of influence on the pile behaviour in the longitudinal direction may be identified as ${\pm}1$-2D (D: tunnel diameter) from the pile centre (behind and ahead of the pile axis in the longitudinal direction) based on the analysis conditions assumed in the current study. Negative excess pore pressure was mobilised near the pile tip, while positive excess pore pressure was computed at the upper part of the pile. It has been found that the serviceability of a pile experiencing adjacent tunnelling is more affected by pile settlement than axial pile force changes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4666-4672
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• 2011

Performance of NOx removal in SCR(Selective Catalytic Reduction) process depends on such various factors as catalyst factors (catalyst composition, catalyst form, space velocity, etc.), temperature of exhaust gas, and velocity distribution of exhaust gas. Especially the flow uniformity of gas stream flowing into the catalyst layer is believed to be the most important factor to influence the performance. In this research, the flow characteristics of a SCR process at design stage was simulated, using 3-dimensional numerical analysis method, to confirm the uniformity of the gas stream. In addition, the effects of guide vanes, baffles, and perforated plates on the flow uniformity for the inside and catalyst layer of the reactor were studied in order to optimize the flow uniformity inside the SCR reactor. It was found that the installation of a guide vane at the inlet duct L-tube part and the installation of a baffle at the upper part is very effective in avoiding chaneling inside the reactor. It was also found that additional installation of a perforated plate at the lower part of the potential catalyst layer buffers once more the flow for very uniform distribution of the gas stream.

• Journal of the Korean Magnetics Society
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• v.22 no.2
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• pp.49-57
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• 2012

From among the NDT (Non-Destructive Testing) methods, the MFL (Magnetic Flux Leakage) PIG (Pipeline Inspection Gauge) is especially suitable for testing pipelines because the pipeline has high magnetic permeability. MFL PIG showed high performance in detecting the metal loss and corrosions. However, MFL PIG is difficult to detect the crack which occured by exterior-interior pressure difference in pipelines and the shape of crack is very long and narrow. Therefore, the new PIG is needed to be researched and developed for detecting the cracks. The CMFL (Circumferential MF) PIG performs magnetic fields circumferentially and can maximize the magnetic flux leakage at the cracks. In this paper, CMFL PIG is designed and the distribution of the magnetic fields is analyzed by using 3 dimensional nonlinear finite element method (FEM). By Simulating and Measuring the magnetic leakage field, it is possible to detect of axial cracks in the pipeline.

• Journal of Korean Society of Disaster and Security
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• v.15 no.2
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• pp.37-44
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• 2022

As the frequency of torrential rains and typhoons increases due to climate change, the frequency of occurrence of debris flow is also increasing. In particular, in the case of Kangwon-do, the occurrence of damage caused by mountain disasters is increasing as it has a topographical characteristic where the mountains and the coast are in contact. In order to analyze the flow characteristics in the sedimentary part of the debris flow, input data were constructed through numerical maps and field data, and a two-dimensional model, FLO-2D, was simulated. The damaged area was divided into the inflow part of the debris flow, the village center, and the vicinity of the port, and the flow center and flow velocity of the debris flow were simulated and compared with field survey data. As a result, the maximum flow depth was found to be 2.4 m at the debris flow inlet, 2.7 m at the center of the village, and 1.4 m at the port adjacent to the port so the results were similar when compared to the field survey. And in the case of the maximum flow velocity, it was calculated as 3.6 m/s at the debris flow inlet, 4.9 m/s in the center of the village and 1.2 m/s in the vicinity of the port, so It was confirmed that the maximum flow center occurred in the section where the maximum flow rate appeared.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.440-453
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• 2019

This study was carried out to investigate the effect of watching a two-dimensional (2D) forest video and a virtual reality (VR) forest video on stress reduction in adults. Experiments were conducted in an artificial climate room, and 40 subjects participated. After inducing stress in the subjects, subjects watched a 2D gray video, 2D forest video, or VR forest video for 5 mins. The autonomic nervous system activity was evaluated continuously in terms of measured heart rate variability during the experiment. After each experiment, the subject's psychological state was evaluated using a questionnaire. The 2D forest video decreased the viewer's stress index, increased HF, and reduced heart rate compared with the 2D gray video. The VR forest video had a greater stress index reduction effect, LF/HF increase effect, and heart rate reduction effect than the 2D gray video. Psychological measurements showed that subjects felt more comfortable, natural, and calm when watching the 2D gray video, 2D forest video or VR forest video. We also found that the 2D forest video and VR forest video increased positive emotions and reduced negative emotions compared to the 2D gray video. Based on these results, it can be concluded that watching the 2D forest and VR forest videos reduces the stress index and heart rate compared with watching the 2D gray video. Thus, it is considered that the 2D forest video increases the activity of the parasympathetic nervous system, and the VR forest video increases the activity of the sympathetic nervous system. The increased activity of the sympathetic nervous system upon watching the VR forest video is judged to be positive sympathetic nerve activity, such as novelty and curiosity, and not negative sympathetic activity, such as stress and tension. The results of this study are expected to be the basis for examining the visual effects of forest healing, with hope that the utilization of VR, the technology of the fourth industrial revolution in the forestry field, will broaden.

• Progress in Medical Physics
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• v.10 no.2
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• pp.63-71
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• 1999

For the purpose of utilization in 3-D conformal radiotherapy and whole body radiosurgery, the Whole Body 3-Dimensional Topographic Radiation Therapy System has been developed. Whole body frame was constructed in order to be installed on the couch. Radiopaque catheters were engraved on it for the dedicated coordinate system and a MeV-Green immobilizer was used for the patient setup by the help of side panels and plastic rods. By designing and constructing the whole body frame in this way, geometrical limitation to the gantry rotation in 3-D conformal radiotherapy could be minimized and problem which radiation transmission may be altered in particular incident angles was solved. By analyzing CT images containing information of patient setup with respect to the whole body frame, localization and coordination of the target is performed so that patient setup error may be eliminated between simulation and treatment. For the verification of setup, the change of patient positioning is detected and adjusted in order to minimize the setup error by means of comparison of the body outlines using 3 CCTV cameras. To enhance efficiency of treatment procedure, this work can be done in real time by watching the change of patient setup through the monitor. The method of image subtraction in IDL (Interactive Data Language) was used to visualize the change of patient setup. Rotating X-ray system was constructed for detecting target movement due to internal organ motion. Landmark screws were implanted either on the bones around target or inside target, and variation of target location with respect to markers may be visualized in order to minimize internal setup error through the anterior and the lateral image information taken from rotating X-ray system. For CT simulation, simulation software was developed using IDL on GUI(Graphic User Interface) basis for PC and includes functions of graphic handling, editing and data acquisition of images of internal organs as well as target for the preparation of treatment planning.

• Korean Security Journal
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• no.24
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• pp.53-66
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• 2010

This study aims to analyze kinematic variables regarding lateral break-fall quantitatively that can protect the body, prevent the injury and minimize the impact. To this end, three Hapkido, judo athletes of H University with experience of over 5 years were selected. Test was conducted through three dimensional image analysis by checking the time and order the subjects reach a mat. In this study, lateral break-fall was repeated five times and among them, the best movement was selected. The picture shot with high-speed camera was analyzed by using KWON3D ver. 3.1 program through three dimensional coordinate calculation based on DLT method and smoothing process of data. Study results were as follows. 1. With respect to time variables shown in lateral break-fall of A, B, C athletes, there is small difference in temporal variables and in the order the body reaches a mat. With respect to average value, hand is ($0.94{\pm}0.20$), elbow ($0.97{\pm}0.17$), hip ($0.97{\pm}0.18$), back ($0.98{\pm}0.18$), and shoulder ($1.04{\pm}0.16$). Time variable the body reaches a mat in lateral break-fall is in hand, elbow, hip, back and shoulder. 2. With respect to moving distance variables shown in lateral break-fall of A, B, C athletes, hand is ($34.33{\pm}34.59$), elbow ($52.00{\pm}26.06$), hip ($70.00{\pm}15.72$), back ($153.67{\pm}17.93$), and should ($130.67{\pm}29.02$). The fact that this study contributed to improving security martial arts technique and protecting the body by understanding the principle of lateral break-fall movement is of significance. In addition, the fact that this study provided systematic basic data for improving security martial arts technique is significant.