• Journal of Radiation Protection and Research
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• v.47 no.4
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• pp.214-225
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• 2022

Background: The conventional cerium-doped Gd₂Al₂Ga₃O₁₂ (GAGG(Ce)) scintillator-based gamma-ray imager has a bulky detector, which can lead to incorrect positioning of the gammaray source if the shielding against background radiation is not appropriately designed. In addition, portability is important in complex environments such as inside nuclear power plants, yet existing gamma-ray imager based on a tungsten mask tends to be weighty and therefore difficult to handle. Motivated by the need to develop a system that is not sensitive to background radiation and is portable, we changed the material of the scintillator and the coded aperture. Materials and Methods: The existing GAGG(Ce) was replaced with Bi₄Ge₃O₁₂ (BGO), a scintillator with high gamma-ray detection efficiency but low energy resolution, and replaced the tungsten (W) used in the existing coded aperture with lead (Pb). Each BGO scintillator is pixelated with 144 elements (12 × 12), and each pixel has an area of 4 mm × 4 mm and the scintillator thickness ranges from 5 to 20 mm (5, 10, and 20 mm). A coded aperture consisting of Pb with a thickness of 20 mm was applied to the BGO scintillators of all thicknesses. Results and Discussion: Spectroscopic characterization, imaging performance, and image quality evaluation revealed the 10 mm-thick BGO scintillators enabled the portable gamma-ray imager to deliver optimal performance. Although its performance is slightly inferior to that of existing GAGG(Ce)-based gamma-ray imager, the results confirmed that the manufacturing cost and the system's overall weight can be reduced. Conclusion: Despite the spectral characteristics, imaging system performance, and image quality is slightly lower than that of GAGG(Ce), the results show that BGO scintillators are preferable for gamma-ray imaging systems in terms of cost and ease of deployment, and the proposed design is well worth applying to systems intended for use in areas that do not require high precision.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6D
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• pp.909-916
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• 2006

This study investigates tourists' sightseeing excursion behaviors and their information usage patterns at Fuji five lakes Area. This paper aims to empirically analyze the relationship between a sightseeing excursion behavior and use of tourist information applying a cluster analysis and a quantitative regression model. The main results are summarized as follows: (1) Tourists' information need is high about 90% of all tourists get information, 80% get the information before travel, 70% on the journey, 60% at the same time. (2) The patterns of information usage are categorized into 3 groups by the timing when tourists try to get the information.(3) There exists a difference among the time-spatial characteristics of excursion's behaviors such as the time after arriving time at sightseeing area, the time till go to home, duration time, and the total travel time between spots, the number of spots, and the size of excursion scale. (4) The quantitative regression model shows that information usage which constrained by time and space significantly determines both the number of the sightseeing spots and the duration time.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.541-547
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• 2006

With the new paradigm of ubiquitous in the developed computing technology, it is urgently necessary to research GIS fields centering around positioning techniques. The intention of this study is to propose implementation methods for integrating topographic and cadastral data. For this purpose an integrated data model is formed to coincide the graphic data of cadastral map with that of topographic map. As a result, the integrated data model could be built by harmonizing cadastral map with topographic map. We suggest data model for connecting with other information systems in the conditions of data uniformity and implementation. This data implementation models suggested in this research can provide a good reference for the future implementation of other systems. This results will be efficiently used as basis for practical use in ubiquitous environments of spatial informations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.731-738
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• 2006

Facing congestion, people want to know traffic information about their routes, especially real-time link travel time (LTT). In this paper, as a sequel paper of the previous non-taxi based LTT generating study by Choi et al. (1998), taxi based GPS probes have been tried to produce LTT for urban arterials. Taxis in itself are good deployment mode of GPS probes although it by nature experiences boarding and alighting time noises which should be accounted. A heuristic real-time dynamic outlier filter algorithm for taxi GPS probe has been developed focusing on urban arterials. An actual traffic survey for dynamic link travel times has been conducted using license plate method for the test arterials of Seoul city transportation network. With the algorithm, it is estimated that 70% of outliers have been filtered and the relative error has been improved by 73.7%. The filtering algorithm developed here would be expected to be in use for other spatial sites with some calibration efforts. Some limitations and future research agenda have also been discussed.

• Journal of Korea Entertainment Industry Association
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• v.13 no.7
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• pp.155-164
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• 2019

This paper studies the possible ways to make the most of Namsadang Nori Deotboegi which has been designated as National Intangible Cultural Property No 3 as well as UNESCO World Intangible Cultural Heritage in training actors. Considering the fact that all six parts of a Namsadang performance were included as Important Intangible Cultural Properties, the historical and traditional value of the itinerant performance troupe is significant. The improvisatory characteristics of witty remarks, the 'Korenness' of the movement and breathing in Deotboegi dance, the spatial awareness realised through performing witty remarks with musician as well as the 'Koreaness' in the emotions conveyed are the particular values of Deotbeogi for training actors. The required ability to listen to the co-performer and not to anticipate what might be said next helps the performer do develop a strong focus to be able to stay in the moment. The heightened awareness of the body, and the ability to control it as well as the awareness of the space including the co-performers are helpful in the context of both traditional and contemporary performance.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.792-799
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• 2022

Building Information Modeling (BIM) technology is a key component of modern construction engineering and project management workflows. As-is BIM models that represent the spatial reality of a project site can offer crucial information to stakeholders for construction progress monitoring, error checking, and building maintenance purposes. Geometric methods for automatically converting raw scan data into BIM models (Scan-to-BIM) often fail to make use of higher-level semantic information in the data. Whereas, semantic segmentation methods only output labels at the point level without creating object level models that is necessary for BIM. To address these issues, this research proposes a hybrid semantic-geometric approach for clutter-resistant floorplan generation from laser-scanned building point clouds. The input point clouds are first pre-processed by normalizing the coordinate system and removing outliers. Then, a semantic segmentation network based on PointNet++ is used to label each point as ceiling, floor, wall, door, stair, and clutter. The clutter points are removed whereas the wall, door, and stair points are used for 2D floorplan generation. A region-growing segmentation algorithm paired with geometric reasoning rules is applied to group the points together into individual building elements. Finally, a 2-fold Random Sample Consensus (RANSAC) algorithm is applied to parameterize the building elements into 2D lines which are used to create the output floorplan. The proposed method is evaluated using the metrics of precision, recall, Intersection-over-Union (IOU), Betti error, and warping error.

• International Area Studies Review
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• v.15 no.1
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• pp.571-583
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• 2011

We use the properties of competitive location equilibrium to study the relationship between the demand for education and the choice of primary residential location. Consumers can work and live in a comparatively high wage place where there are few education opportunities, or live in a place where education is available and commute to work. If education and employment are each location-specific, there are pooling equilibria in which consumers locate according to their preference for education. In general, the stronger the taste for education, the greater the attraction of living close to the education site and the lower the demand for other goods, including housing. Exploring the effects of the model parameters on the spatial distribution of consumers, we find that a higher frequency of trips taken to the education site, a shorter distance between the work place and the education site, or a greater out-of-pocket education cost each leads to a wider range of consumer types selecting to reside at the education location. We also find that a higher wage lowers the range of consumers who select to live near the education site.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.403-411
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• 2013

Horizontal construction projects such as oil and gas pipeline projects typically involve repetitive-work activities with the same crew and equipment from one end of the project to the other. Repetitive scheduling also known as linear scheduling is known to have superior schedule management capabilities specifically for such horizontal construction projects. This study discusses on expanding the capabilities of repetitive scheduling to account for the variance in production rates and visual representation by developing an automated alignment based linear scheduling program for applying temporal and spatial changes in production rates. The study outlines a framework to apply changes in productions rates when and where they will occur along the horizontal alignment of the project and illustrates the complexity of construction through the time-location chart through a new linear scheduling model, Linear Scheduling Model with Varying Production Rates (LSM_VPR). The program uses empirically derived production rate equations with appropriate variables as an input at the appropriate time and location based on actual 750 mile natural gas liquids pipeline project starting in Wyoming and terminating in the center of Kansas. The study showed that the changes in production rates due to time and location resulted in a close approximation of the actual progress of work as compared to the planned progress and can be modeled for use in predicting future linear construction projects. LSM_VPR allows the scheduler to develop schedule durations based on minimal project information. The model also allows the scheduler to analyze the impact of various routes or start dates for construction and the corresponding impact on the schedule. In addition, the graphical format lets the construction team to visualize the obstacles in the project when and where they occur due to a new feature called the Activity Performance Index (API). This index is used to shade the linear scheduling chart by time and location with the variation in color indicating the variance in predicted production rate from the desired production rate.

• Human Ecology Research
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• v.61 no.4
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• pp.543-563
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• 2023

The purpose of this study is to design and develop a Metaverse ZEP platform-based teaching and learning process plan by selecting learning topics that are commonly dealt with among the core concepts of the "family" area of practical (technical and home) subjects. To this end, a teaching and learning process plan was developed through planning, Metaverse platform design, expert review, and revision stages. The Metaverse ZEP "Open Class Day" platform, a virtual learning space, was created and developed to further utilize EduTech programs, such as Padlet, Mentimeter, Jamboard, Miricanvas, and Spatial. The teaching and learning process plan developed in this study consists of a total of seven sessions, including approaching EduTech, Changing Families, Exploring Our Family, and Counseling Centers 1, 2, and 3. Among them, Geumji Counseling Center 1, 2, and 3 was designed as a class in which parents and children participate together in open classes using the ZEP platform. This platform can be used as part of parent classes as well as to encourage online participation in the open classes held periodically at each individual school. In terms of the content validity ratio (CVR) of the developed teaching and learning process verified through five experts, 12 out of 15 questions had a CVR of 1, while the remaining three questions had a CVR of 0.6. The three questions with lower validity were revised and supplemented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.145-155
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• 2023

A radial combiner with high efficiency characteristics in the X-band was designed and manufactured using a waveguide and matching structure. In particular, in order to manufacture it in a small size, a dual waveguide to coaxial transition structure was applied that allows two ports to be matched to one waveguide. Applying this structure makes it possible to manufacture smaller than typical coaxial to waveguide radial combiner. As a result of measurement in the X-band band of 9.2~10GHz, the return loss was less than -18.408dB and the output insertion loss was less than 0.206dB, and the output combining efficiency was obtained as high as 95.37% or more. It is expected that it can be used in the combining part for high output transmitters in the millimeter wave band in the future. In particular, the range of use is expected to increase by reducing the size and weight.