• Journal of the Korean association of regional geographers
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• v.14 no.5
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• pp.587-603
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• 2008

The Woong-Chi region is located between Wan-ju and Jin-an had experienced transportation route change from past continuously. The difference of relative height especially steep slope of western side is given to the most difficulty for transportation route open in Woong-Chi region. For the overcome this restraint geomorphological condition, multi-route were developed according to available purpose in walking period. They effort to decrease of slope and curve in route continual1y, and only used the conditioned route for automobile from 1910s in automobile period. The social aspect in transportation route change on this region is, firstly, the transportation route has trend from variety to simplicity. Secondary, new transportation route is opened by social needs such as traffic accident and social big event. Thirdly, the regional range was extended for overcome restraint condition. Fourthly, the rise and fall of route related settlement is influenced by transportation route change. The used technical method for the overcome the geomorphological condition is make a tunnel, alleviate the curve radius, alleviate the slop and consider the direction of the sunny than shady side.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.660-668
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• 2018

The main object of this study was to find a way to operate the marker for simulating a virtual construction using a MR(mixed reality) device. The secondary object was to find a way to extract the form-data from BIM data, and to represent the virtual object by the MR device. A tiny error of scale causes large errors of length because the architectural objects are very large. The scale was affected by the way that the camera of the MR device recognizes the marker. The method of installing and operating the marker causes length errors in the virtual object in the MR system. The experimental results showed that the error factor of the Virtual object's length was 0.47%. In addition, the distance between the markers can be decided through the results of an experiment for the multi-marker tracking system. The minimum distance between markers should be more than 5 m, and the error of length was approximately 23mm. If the represented virtual object must be less than 20mm in error, the particular mark should be installed within a 5 m radius of it. Based on this research, it is expected that utilization of the MR device will increase for the application of virtual construction simulations to construction sites.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.1
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• pp.73-81
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• 2019

The purpose of this study is to draw safe environmental project factors for enhancing the safety of children in peripheral space around children's park and suggest environmental project measures for peripheral spaces around children's parks, based on the survey of children's park users' consciousness on peripheral spaces. Physical space range for this study was limited to low-rise housing area wihtin the radius of 250m, as peripheral spaces around children's parks in which children's playgrounds were built. In addition, the target areas for examining users' consciousness on peripheral spaces around children's parks were selected according to following criteria. 1)areas with highter portion of children; 2) those with higher portion of single-family houses/multi-housing/tenement houses, which constitute low-rise housing areas; and 3) those with higher safety accident rate of children, which was measured based on criminal and traffic accidents. The finding are as follows: first, users' consciousness on safety accidents that are likely to occur in peripheral spaces around children's parks was examined to show that there is most prominent difference between satisfaction and necessity. This result suggests that users are clearly conscious of the necessity of environmental improvement rather than the satisfaction with the current peripheral environment around children's park.; second, for the difference between satisfaction with and necessity of environmental project factors for access/boundary spaces around children's pakrs, there is most significant difference between the satisfaction with and the necessity of establishment of facilities against illegal parking for clear visibility of community roads, for access spaces, and the separate establishment of bicycle racks around main entry into parks, for boundary spaces. Users' necessity of the establishment of them is judged to be derived from the fact that the safety of children and even adults is threatened, because bicycles invaded into the deep inside of children parks. This study analyzed a correlation between satisfaction and necessity through factor and IPA analysis, and should be initially considenred if the future environmental improvement project would be conducted to promote safe environment in peripheral spaces around children's parks in the future. It will be necessary to provide practical environmental project factors through a field investigation.

• Analytical Science and Technology
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• v.17 no.2
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• pp.108-116
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• 2004

The adsorption characteristics of raw and crosslinked chitosan for rare earth elements (REEs) have been studied. The range of optimum pH for the maximum adsorption was observed: pH 4.5~5.5 for $Nd^{3+}$, $Tm^{3+}$ on raw and crosslinked chitosan; pH 4.0~5.5 for $La^{3+}$ and $Ce^{3+}$ on crosslinked chitosan and pH 2.0 for those on raw chitosan. The adsorption rate of REE at pH 4.0 has been found in the order of $Er^{3+}$ > $Gd^{3+}$ > $Yb^{3+}$ > $Nd^{3+}$ > $Lu^{3+}$ > $Eu^{3+}$ > $Tm^{3+}$ > $Ho^{3+}$ > $Dy^{3+}$ > $La^{3+}$ > $Ce^{3+}$ > $Y^{3+}$ > $Pr^{3+}$ in single metal system and that of $Lu^{3+}$ > $Yb^{3+}$ > $Tm^{3+}$ > $Dy^{3+}$ > $Ho^{3+}$ > $Er^{3+}$ > $Eu^{3+}$ > $Gd^{3+}$ > $Nd^{3+}$ > $Y^{3+}$ > $La^{3+}=Ce^{3+}=Pr^{3+}$ in multi metal system. In the competitive adsorption of multi metal system, the amount of metal adsorption generally increased with increasing atomic number and with decreasing ionic radius. On the adsorption studies of metal ions on chitosan, the time of equilibrium adsorption which was reached at the maximum adsorption was about 5 hours. 83~95 % for $Nd^{3+}$ ion and 90~106 % for $Tm^{3+}$ ion, were recovered from the crosslinked chitosan.

• The Korean Journal of Nuclear Medicine
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• v.38 no.4
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• pp.318-324
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• 2004

Purpose: Philips GEMINI is a newly introduced whole-body GSO PET/CT scanner. In this study, performance of the scanner including spatial resolution, sensitivity, scatter fraction, noise equivalent count ratio (NECR) was measured utilizing NEMA NU2-2001 standard protocol and compared with performance of LSO, BGO crystal scanner. Methods: GEMINI is composed of the Philips ALLEGRO PET and MX8000 D multi-slice CT scanners. The PET scanner has 28 detector segments which have an array of 29 by 22 GSO crystals ($4{\times}6{\times}20$ mm), covering axial FOV of 18 cm. PET data to measure spatial resolution, sensitivity, scatter fraction, and NECR were acquired in 3D mode according to the NEMA NU2 protocols (coincidence window: 8 ns, energy window: $409[\sim}664$ keV). For the measurement of spatial resolution, images were reconstructed with FBP using ramp filter and an iterative reconstruction algorithm, 3D RAMLA. Data for sensitivity measurement were acquired using NEMA sensitivity phantom filled with F-18 solution and surrounded by $1{\sim}5$ aluminum sleeves after we confirmed that dead time loss did not exceed 1%. To measure NECR and scatter fraction, 1110 MBq of F-18 solution was injected into a NEMA scatter phantom with a length of 70 cm and dynamic scan with 20-min frame duration was acquired for 7 half-lives. Oblique sinograms were collapsed into transaxial slices using single slice rebinning method, and true to background (scatter+random) ratio for each slice and frame was estimated. Scatter fraction was determined by averaging the true to background ratio of last 3 frames in which the dead time loss was below 1%. Results: Transverse and axial resolutions at 1cm radius were (1) 5.3 and 6.5 mm (FBP), (2) 5.1 and 5.9 mm (3D RAMLA). Transverse radial, transverse tangential, and axial resolution at 10 cm were (1) 5.7, 5.7, and 7.0 mm (FBP), (2) 5.4, 5.4, and 6.4 mm (3D RAMLA). Attenuation free values of sensitivity were 3,620 counts/sec/MBq at the center of transaxial FOV and 4,324 counts/sec/MBq at 10 cm offset from the center. Scatter fraction was 40.6%, and peak true count rate and NECR were 88.9 kcps @ 12.9 kBq/mL and 34.3 kcps @ 8.84 kBq/mL. These characteristics are better than that of ECAT EXACT PET scanner with BGO crystal. Conclusion: The results of this field test demonstrate high resolution, sensitivity and count rate performance of the 3D PET/CT scanner with GSO crystal. The data provided here will be useful for the comparative study with other 3D PET/CT scanners using BGO or LSO crystals.