• Journal of Korea Planning Association
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• v.54 no.2
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• pp.93-108
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• 2019

This study examines the relationship between three-dimensional urban built environment and urban surface temperature using LANDSAT 8 satellite image data in Seoul city. The image was divided into 600m×600m grid units as an unit of analysis. Due to the high level of spatial dependency in surface temperature, this study uses spatial statistics to take into account spatial auto-correlation. The spatial error model shows the best goodness of fit. The analysis results show that the three-dimensional built environment and transport environment as well as natural environment have statistically significant associations with surface temperature. First, natural environment variables such as green space, streams and river, and average elevation show statistically significant negative association with surface temperature. Second, the building area shows a positive association with surface temperature. In addition, while sky view factor (SVF) has a positive association with surface temperature, surface roughness (SR) shows a negative association with it. Third, transportation related variables such as road density, railway density, and traffic volume show positive associations with surface temperature. Moreover, this study finds that SVF and SR have different effects on surface temperature in regard to the levels of total floor areas in built environment. The results indicate that interactions between floor area ratio (FAR) and three-dimensional built environmental variables such as SVF and SR should be considered to reduce urban surface temperature.

• Journal of Korea Planning Association
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• v.54 no.7
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• pp.58-69
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• 2019

This study suggested the necessity of introducing the future-oriented new industrial complex as a way to enhance the competitiveness of the industrial complex in response to the industrial ecosystem change caused by the 4th industrial revolution. To evaluate the location suitability for the new industrial complex, location indices were developed in this study. The flexibility of location and connectivity to neighboring areas of the future-oriented new industrial complexes were the focused subjects of this study. In-depth expert consultation and Delphi survey were conducted to construct an index system and to measure the indices. Afterwards, the AHP analysis was conducted to elucidate the weighting by indicators. As a result, the indicators of industrial innovation environment were the most important in the major category. In addition, the convenience of workers, especially urban environment, was analyzed as an important factor for success of the future-oriented new industrial complex. The indicators which are closely related to the concept and purpose of the future-oriented new industrial complex turned out to have the higher weight compared to other indicators. From the point of view of the developers of the industrial complexes or tenant companies, the implications for deriving suitable locations for development of industrial complexes among urban under-utilized sites are suggested. Furthermore, It is expected that the government will be able to apply the development system to stimulate the development of these new industrial complexes and to prepare guidelines for selecting locations.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.755-767
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• 2020

A significant development has been made on a new fatigue damage model applicable to Gaussian wide band stress response spectra using numerical approximation methods such as data processing, time simulation, and regression analysis. So far, most of the alternative approximate models provide slightly underestimated or overestimated damage results compared with the rain-flow counting distribution. A more reliable approximate model that can minimize the damage differences between exact and approximate solutions is required for the practical design of ships and offshore structures. The present paper provides a detailed description of the development process of a new fatigue damage model. Based on the principle of the Gaussian wide band model, this study aims to develop the best approximate fatigue damage model. To obtain highly accurate damage distributions, this study deals with some prominent research findings, i.e., the moment of rain-flow range distribution MRR(n), the special bandwidth parameter μk, the empirical closed form model consisting of four probability density functions, and the correction factor QC. Sequential prerequisite data processes, such as creation of various stress spectra, extraction of stress time history, and the rain-flow counting stress process, are conducted so that these research findings provide much better results. Through comparison studies, the proposed model shows more reliable and accurate damage distributions, very close to those of the rain-flow counting solution. Several significant achievements and findings obtained from this study are suggested. Further work is needed to apply the new developed model to crack growth prediction under a random stress process in view of the engineering critical assessment of offshore structures. The present developed formulation and procedure also need to be extended to non-Gaussian wide band processes.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.343-350
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• 2021

3D printing technology is an additive manufacturing technology produced through 3D scanning or modeling method. This technology can be produced in a short time without mold, which has recently been applied in earnest in various fields. In the medical field, 3D printing technology is used in various fields of radiology and radiation therapy, but related research is insufficient in the field of nuclear medicine. In this study, we compare the characteristics of traditional nuclear medicine phantom with 3D printing technology and evaluate its applicability in clinical trials. We manufactured the same size phantom of poly methyl meta acrylate(PMMA) and acrylonitrile butadiene styrene(ABS) based on the aluminum step wedge. We used BrightView XCT(Philips Health Care, Cleveland, USA) SPECT/CT. We acquired 60 min list mode for Aluminum, PMMA and ABS phantoms using Rectangular Flood Phantom (Biodex, New York, USA) ^99mTcO₄ 3 mCi(111 MBq), 6 mCi (222MBq) and ⁵⁷Co Flood phantom(adq, New Hampshire, USA). For the analysis of acquired images, the region of interest(ROI) were drawn and evaluated step by step for each phantom. Depending on the type of radioisotope and radiation dose, the counts of the ABS phantom was similar to that of the PMMA phantom. And as the step thickness increased, the counts decreased linearly. When comparing the linear attenuation coefficient of Aluminum, PMMA and ABS phantom, the linear attenuation coefficient of the aluminium phantom was higher than that of the others, and the PMMA and ABS phantom had similar the linear attenuation coefficient. Based on ABS phantom manufactured by 3D printing technology, as the thickness of the PMMA phantom increased, the counts and linear attenuation coefficient decreased linearly. It has been confirmed that ABS phantom is applicable in the clinical field of nuclear medicine. If the calibration factor is applied through further research, it is believed that practical application will be possible.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1067-1073
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• 2021

Participants in the virtual environment will have an immersive and memorable perceived experience through interacting with virtual objects. Recently, commercial virtual reality technologies have released simple and cost-effective smartphone-based head-mounted displays (HMD) and high-quality wide field-of-view (FOV) HMDs. However, due to the vergence-accommodation conflict structure of HMD and the learned cognition mechanism in real, side effects such as dizziness and nausea remain challenging to overcome. This study focuses on consistent size perception among various cognitive difference factors, which are essential for interaction with virtual objects. We verified whether the visual angle, which affects the size perception of an object in real, is also the main factor in the virtual environment. Our experiments derived the relation between the visual angle and the environmental components, shadow, and grid, which help perceive a virtual object. As a result of the regression analysis, we presented that in the small FOV HMD environment, the visual angle affects size perception, and the relation between the shadow and the grid is statistically significant.

• International Journal of Advanced Culture Technology
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• v.10 no.1
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• pp.24-35
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• 2022

The purpose of this study was to form a linked model in which local institutions related to lifelong education for the disabled can cooperate based on the Daegu University K-PACE Center. The contents of the study started with recognizing the problem that the adult-centered lifelong education support system does not effectively cope with these factors, even though the independent life of people with developmental disabilities is a major factor determining the quality of life. Regarding this problem recognition, this study primarily emphasized the view that educational support for independent life of people with developmental disabilities should establish the context of the school foundation. The context of the school foundation is established for lifelong education centered on adulthood for people with developmental disabilities because the curriculum is embodied through the standards of subject matter education. In this regard, the Daegu University K-PACE Center, which established a curriculum that supports the independent life of people with developmental disabilities in terms of linking higher and lifelong education, actually reflects the context of the school foundation. As a result, this study prepared a strategy that could be considered as a transition to advance the curriculum organized by the Daegu University K-PACE Center, and the strategy was secondarily reflected as a procedure that could be linked to local lifelong education-related institutions for the disabled. Finally, this study presented a form of transition in which people with developmental disabilities can access the curriculum of lifelong education through the connection of local lifelong education-related institutions for the disabled, centering on the entire life of adulthood.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.333-342
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• 2022

This study analyzed the effects of start-up preparations for start-ups, start-up support for start-ups, and accelerator support on business satisfaction for start-ups. For this purpose, an empirical analysis was conducted on 308 founders. The main empirical study results are as follows. Start-up preparation, start-up support, and accelerator support have positive(+) significance in the start-up satisfaction of start-up companies. Among the variables that had a significant effect, the preparation of the start-up team was found to have the greatest influence. These results are considered to be consistent with the view that the importance of the private start-up support system is gradually increasing in the start-up ecosystem, and that the composition of the start-up team is the most important factor in start-up.

• Journal of Industrial Convergence
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• v.20 no.6
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• pp.7-15
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• 2022

Recently, due to the development of AI and big data technologies following the advent of the era of the 4th Industrial Revolution, the emerging metaverse industry is emerging as a new business, and in particular, from this point of view, this paper analyzes the history of metaverse and the pros and cons of "Geppetto", which is the most popular in the Korean metaverse market, and aims to give an appropriate direction for future development based on this. In order to carry out this study, we first used SWOT analysis techniques as an initial enterprise analysis method to examine the strengths and weaknesses, opportunities and threat requirements, and derive the status of each factor. Based on the factors in each of the subsequent derivatives, we wanted to explore the TOWS development strategy and present significant implications based on this.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.3194-3210
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• 2022

Wall obstruction is the main factor leading to the non-line of sight (NLoS) error of indoor localization based on received signal strength indicator (RSSI). Modeling and correcting the path loss of the signals through the wall will improve the accuracy of RSSI localization. Based on electromagnetic wave propagation theory, the reflection and transmission process of wireless signals propagation through the wall is analyzed. The path loss of signals through wall is deduced based on power loss and RSSI definition, and the theoretical model of path loss of signals through wall is proposed. In view of electromagnetic characteristic parameters of the theoretical model usually cannot be accurately obtained, the statistical model of NLoS error caused by the signals through the wall is presented based on the log-distance path loss model to solve the parameters. Combining the statistical model and theoretical model, a hybrid model of path loss of signals through wall is proposed. Based on the empirical values of electromagnetic characteristic parameters of the concrete wall, the effect of each electromagnetic characteristic parameters on path loss is analyzed, and the theoretical model of regional path loss of signals through the wall is established. The statistical model and hybrid model of regional path loss of signals through wall are established by RSSI observation experiments, respectively. The hybrid model can solve the problem of path loss when the material of wall is unknown. The results show that the hybrid model can better express the actual trend of the regional path loss and maintain the pass loss continuity of adjacent areas. The validity of the hybrid model is verified by inverse computation of the RSSI of the extended region, and the calculated RSSI is basically consistent with the measured RSSI. The hybrid model can be used to forecast regional path loss of signals through the wall.

• Journal of the Korean Society for Library and Information Science
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• v.56 no.1
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• pp.277-296
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• 2022

Despite the characteristics of public data with various potentials, few studies have been conducted on general users who lack an understanding of data as well as on expansion of the service uses. This study examined which digital-service-quality factors affect the intention to continue using public data services based on the expectation confirmation theory. As a result of the analysis, satisfaction partially mediated between expectation agreement and continued use intention for understandability and efficiency, which were combined as one factor, and completely mediated the relationship between perceived usefulness expectation agreement and continued use intention. It can be seen that the more the understanding and usefulness of the information provided by the service is satisfied, the higher the willingness to use it. Accordingly, it suggested adding an electronic bookmark function and the provision of online community for users to improve the overall quality of services. This study is significant in that it provided evidence on which part to focus on when designing electronic services from the point of view of general users.