• Journal of Korean Association for Spatial Structures
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• v.8 no.6
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• pp.85-94
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• 2008

This paper is concerned with the domestic and foreign PV integrated projects in view of structural design. These projects are classified with public and display 6 facilities. The evaluated items are natural integration with building, engineering details and innovative new design. 6 domestic public and display facilities are frequently using isolated supporting system at roof, but show weakness in design integration. But the cases, using the PV panel in the stage of design some display facilities, are increasing. In the other hand, foreign public and display facilities are using the modul connection majorly and the structural and design integration are obtained.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.385-388
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• 2002

We measured and evaluated digital, pre-sampling and overall imaging properties (characteristic curves, Modulation Transfer Function (MTF), Wiener spectra (WS), Noise Equivalent Quanta (NEQ) and Detective Quantum Efficiency (DQE)) for the direct type and indirect type of Flat-Panel Detector (FPD). First, the digital and overall characteristic curves of the both types of FPD had more wide dynamic range than that of the S/F system. Second, the pre-sampling and overall MTF of the direct-type FPD were superior to those of the indirect-type FPD. Third, for identical exposures, the digital and overall WS of the direct-type FPD were similar or worse than those of the indirect-type FPD, and for larger exposure, the digital WS of the both types of FPD were smaller, but overall WS of the both types of FPD were larger. Fourth, the digital and overall NEQ and DQE of the direct-type FPD were worse than both NEQ and DQE of the indirect-type FPD at lower spatial frequencies, but were better at higher spatial frequencies.

• Journal of Korean Association for Spatial Structures
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• v.10 no.2
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• pp.117-126
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• 2010

Experiment on flexural analysis of RC beams strengthened with composite material panel is presented. Recently, the strengthening of reinforced concrete structures using advanced fiber reinforced plastic (FRP) composites, and in particular the behavior of FRP-reinforced concrete structure is topic that has become very popular because of good corrosion resistance and easy for site handling due to their light weight. In this study, an efficient computational analysis using ABAQUS to predict the ultimate moment capacity of reinforced concrete beams strengthened with FRP is presented. Test parameters in this study are the shape of fiber arrangement (LT, DB, DBT) and the number of carbon fiber sheets (2ply, 3ply). When comparing with results of the analytical model, results of the experiments show similar values. Furthermore, reinforced concrete beam with FRP obtains improved effects for ultimate strength.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.15-24
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• 2013

Purpose: With the demand of SPECT/CT increasing, the interest in complex diagnostic information of CT is rising along with the expansion of various studies on potential performance value. But the study on reduction of exposure dose generated by CT is not being conducted enough. Therefore, in this study, the goal is to identify how much dose reduction exists when performing the extremity bone SPECT/CT using the flat-panel CT. Materials and Methods: The extremity bone SPECT/CT was performed with two equipments -BrightView XCT (Philips Healthcare, Cleveland, USA) and Brilliance 16 CT (Philips Healthcare, Cleveland, USA)-to identify the exposed dose and image quality resulted by changing scan parameter (mAs) applying for both equipment respectively. The noise value of image and spatial resolution were measured with AAPM CT phantom. Tube voltage (kVp) was fixed to 120 kVp, tube current (mAs) calculated at different mA (20, 30, 40, 50, 60, 70, 80) was applied to both equipments respectively. DLP (dose length product) were calculated at the same distance at respective mAs. Also, we acquired images and % contrast with NEMA IEC body phantom to confirm the effect on image. The output of statistics was analyzed by SPSS ver.18. Results: Regarding AAPM phantom, the noise decreased as the tube current (mAs) increased and flat-panel had less noise than Helical CT. This difference increased at lower dose exposure. As to the evaluation of spatial resolution, we can differentiate the space up to 0.75 mm with both equipments. With scan parameter (mA) growing, the value of DLP increased up to 54-216 mGy cm at flat-panel CT and up to 177-709 mGy cm at Helical CT. Regarding NEMA IEC body phantom, same sphere with varied parameter (mA) shows that similar results. Conclusion: There is no significant differences of image quality in both flat-panel and Helical CT when the scan parameter (mA) is changed respectively. Moreover, we can identify the reduction of exposure dose and confirm %contrast analysis value with maintaining image quality. Therefore, at the extremity bone SPECT/CT requiring high spital resolution without the wide ROI, the flat-panel CT is considered to be more useful and it expected to result in the similar image quality with lower exposure dose compared to Helical CT. Additionally, through this study, we expect to help the reduction of the unnecessary exposure dose.

• ETRI Journal
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• v.41 no.1
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• pp.23-31
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• 2019

Since the late 20th century, there has been rapid development in the display industry. Only 30 years ago, we used big cathode ray tube displays with poor resolution, but now most people use televisions or smartphones with very high-quality displays. People now want images that are more realistic, beyond the two-dimensional images that exist on the flat screen, and digital holography-one of the next-generation displaysis expected to meet that need. The most important parameter that determines the performance of a digital hologram is the pixel pitch. The smaller the pixel pitch, the higher the level of hologram implementation possible. In this study, we fabricated the world-smallest $3-{\mu}m$-pixel-pitch holographic backplane based on the spatial light modulator technology. This panel could display images with a viewing angle of more than $10^{\circ}$. Furthermore, a comparative study was conducted on the fabrication processes and the corresponding holographic results from the large to the small pixel-pitch panels.

• Asian Journal of Innovation and Policy
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• v.10 no.2
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• pp.212-235
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• 2021

In spite of the increasing popularity of the Ricardian model for the study of the impact of climate change on agriculture, there has been few attempts to examine the role of interregional spillovers in this framework and all of them rely on geographical proximity-based weighting schemes. We remedy to this gap by focusing on the spatial externalities of surface water flow used for irrigation purposes and demonstrate that farmland value, the usual dependent variable used in the Ricardian framework, is a function of the climate variables experienced locally and in the upstream locations. This novel approach is tested empirically on a spatial panel model estimated across the counties of the Southwest USA over 1997-2012. This region is one of the driest in the country, hence its agriculture relies heavily on irrigated surface water. The results highlight how the weather conditions in upstream counties significantly affect downstream agriculture, thus the actual impact of climate change on agriculture and subsequent adaptation policies cannot overlook the streamflow network anymore.

• Advanced Composite Materials
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• v.17 no.2
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• pp.125-137
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• 2008

FBG (Fiber Bragg Grating) sensors and optical fibers were embedded into CFRP dry preforms before resin impregnation in VaRTM (Vacuum-assisted Resin Transfer Molding). The embedding location was the interface between the skin and the stringer in a CFRP-stiffened panel. The reflection spectra of the FBG sensors monitored the strain and temperature changes during all the molding processes. The internal residual strains of the CFRP panel could be evaluated during both the curing time and the post-curing time. The temperature changes indicated the differences between the dry preform and the outside of the vacuum bagging. After the molding, four-point bending was applied to the panel for the verification of its structural integrity and the sensor capabilities. The optical fibers were then used for the newly-developed PPP-BOTDA (Pulse-PrePump Brillouin Optical Time Domain Analysis) system. The long-range distributed strain and temperature can be measured by this system, whose spatial resolution is 100 mm. The strain changes from the FBGs and the PPP-BOTDA agreed well with those from the conventional strain gages and FE analysis in the CFRP panel. Therefore, the fiber-optic sensors and its system were very effective for the evaluation of the VaRTM composite structures.

• Health Policy and Management
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• v.30 no.1
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• pp.50-61
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• 2020

Background: This study aims to analyze the effects of air pollutants, such as particular matter, to the number of outpatient visits for allergic rhinitis in eup, myeon, and dong administrative boundaries. Methods: Dependent variable was the number of outpatient visits for allergic rhinitis per 10,000 people by region. Independent variables were air pollutants such as PM₁₀, PM_2.5, SO₂, O₃, CO₂, NO₂, and temperature that estimated by using Kriging analysis in all eup, myeon, and dong boundaries. Panel analysis was applied for the analysis to prove the relation between outpatient visits and the concentration of air pollutants. Results: Analysis results showed that particular matter concentration varied by regions and season. Panel analysis showed that outpatient visits for allergic rhinitis had positive relationships with PM₁₀, PM_2.5, SO₂, O₃, and CO₂ in all panel models. Conclusion: Regional variation of particular matter concentration should be considered in establishing regional policies for allergic rhinitis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.535-538
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• 2005

The purpose of this work is to study a process organization on space cognition by visio-auditory stimulation. We develop the system of visuo-auditory stimulation and Humans responses measurement to observe the relationship between the sensory and the motor system fur the localization of visual and auditory target direction in the space. The experiments is performed in a soundproof chamber, 2163 red, green and yellow LED(Luminescent Diode, Brightness: $20cd/m^2$ 1 degree apart each other)arrayed in front of half-circle panel were used and 57 Speaker(5 degree apart each other) arrayed in the hidden of half-circle panel. Physiological parameters such as EOG (Electro-Oculography), head movement and their synergic control are measured by BIOPAC system and Optotrak Certus. This result shows that the response latency time of the perception motion in the center is laster than the periphery of panel. These results can be used in the study of characterizing the spatial cognition.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.2
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• pp.124-128
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• 2017

A light guide improves the spatial resolution of a gamma ray imaging system by diffusing the scintillation light. Similarly, light diffusion film, which has been applied to flat-panel-display engineering, spreads the light from the light guide panel. In this study, we adopted light diffusion film for the light guide of a gamma ray imaging system, and evaluated its diffusion characteristics. We compared the light diffusion performance of the film to an ordinary acrylic plate. As a result, the diffusion film widely spreads scintillation light. As for the thickness of the light guide, we acquired more distinct images with three films overlapped than with an acrylic plate. We expect light diffusion film to be a promising candidate for light guides in gamma ray imaging systems.