• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.207-212
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• 2023

Near-infrared (NIR) absorbing dyes have been applied to various applications such as optical filters, biotechnology, energy storage and conversion, coating additive, and traditionally information-storage materials. Because image sensors used in cellphones and digital cameras have sensitivity in the NIR region, the NIR cut-off filter is essential to achieving more clear images. As energy storage and conversion have been important, diverse NIR absorbing materials have been developed to extend the absorption region to the NIR region, and NIR absorbing materials-based research has proceeded to improve device performances. Adding NIR-absorbing dye with a photo-thermal effect to a self-healable coating system has been attractive for future mobility technology, and more effective self-healing properties have been reported. In this report, the chemical structures of representative NIR-absorbing dyes and state of the art research based on NIR-absorbing dyes are introduced.

• Journal of the Korean Regional Science Association
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• v.39 no.2
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• pp.3-18
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• 2023

The aim of this study is to analyze problems with regional development projects by examining their actual conditions and to propose measures to promote such projects based on the size of local cities. To achieve this goal, problems associated with regional development projects were analyzed, and measures for their promotion were derived by dividing these projects into planning, strategy, policy, and institutional sectors according to the size of local cities. The problems identified with regional development projects include diversification leading to similar and overlapping projects, lack of participation by local experts, top-down government structure for designating and supporting regional development projects, and insufficient budget. In order to address these issues, local experts have suggested differential measures based on the size of local cities. Specifically, in the planning sector, it was proposed that economic, cultural, social, and welfare functions be expanded and reorganized primarily around small and medium-sized cities, and that long-term strategies be established for regional large cities through various partnerships and step-by-step procedures. In the policy sector, it was suggested that the implementation of bottom-up development under the leadership of local governments should be focused on small and medium-sized cities, and that the transition from a specific industry-oriented policy to a corporate growth policy needs to be established around large cities. Finally, in the institutional sector, it was recommended that a performance evaluation system for the use of financial resources and a system for expanding financial resources should be established primarily in small and medium-sized cities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.249-256
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• 2022

Various studies are being actively conducted to show that the real-time visualization technology that combines BIM (Building Information Modeling) and AR (Augmented Reality) helps to increase construction management decision-making and processing efficiency. However, when large-capacity BIM data is projected into AR, there are various limitations such as data transmission and connection problems and the image cut-off issue. To improve the high efficiency of visualizing, a mesh optimization algorithm based on the k-nearest neighbors (KNN) classification framework to reconstruct BIM data is proposed in place of existing mesh optimization methods that are complicated and cannot adequately handle meshes with numerous boundaries of the 3D models. In the proposed algorithm, our target BIM model is optimized with the Unity C# code based on triangle centroid concepts and classified using the KNN. As a result, the algorithm can check the number of mesh vertices and triangles before and after optimization of the entire model and each structure. In addition, it is able to optimize the mesh vertices of the original model by approximately 56 % and the triangles by about 42 %. Moreover, compared to the original model, the optimized model shows no visual differences in the model elements and information, meaning that high-performance visualization can be expected when using AR devices.

• Journal of Intelligence and Information Systems
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• v.29 no.2
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• pp.189-217
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• 2023

The metaverse is a virtual world where individuals engage in social, economic, and cultural activities using avatars, which represent an alternate version of oneself within the virtual realm. While the metaverse has garnered global attention recently, research exploring the identity manifested through avatars within the metaverse remains limited. This study investigates the influence of four IT artifact characteristics related to avatar usage in the metaverse-avatar representation, avatar copresence, avatar profiling, and avatar-space interaction-on perceived avatar identity verification. A survey was conducted with 196 experienced users of the Zepeto platform, and hypotheses were tested using structural equation modeling. The analysis results indicate that the use of IT artifacts enabling avatar representation, avatar copresence, and avatar-space interaction has a positive impact on perceived avatar identity verification. This achieved self-verification indirectly influences the satisfaction and subsequent intention to continue using the metaverse. This study contributes to the academic field by empirically verifying the metaverse technological factors that influence the projected identity onto avatars within the metaverse. Furthermore, it is expected to provide effective guidelines for metaverse platform companies in designing and implementing the metaverse.

• 한국체육학회지인문사회과학편
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• v.55 no.3
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• pp.349-363
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• 2016

The purpose of this study was to perceived interactivity about experience of using dance video contents and intention to use. This study was examine an adaptive model of Technology Acceptance Model and focused on YouTube. In order to achieve the purpose of this study, total 350 questionnaires were surveyed and 311 data were finally analyzed. All data were processed through SPSS for Windows 20.0 version and AMOS 18.0. For the analysis of data, frequency analysis, reliability analysis, confirmatory factor analysis, correlation analysis, model evaluation, and structural equation modeling techniques. The results were as follows. first. Perceived Interactivity had not affect on perceived usefulness but two-way communication, user control among the sub-factor in perceived Interactivity had a positive effect on perceived ease of use. second, perceived ease of use had a positive effect on perceived usefulness. Lastly, Perceived usefulness had not affect intention to use, but perceived ease of use had a positive effect on intention use.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.43-45
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• 2021

The short-term quantitative precipitation prediction (QPF) system is important socially and economically to prevent damage from severe weather. Recently, many studies for short-term QPF model applying the Deep Neural Network (DNN) has been conducted. These studies require the sophisticated pre-processing because the mistreatment of various and vast meteorological data sets leads to lower performance of QPF. Especially, for more accurate prediction of the non-linear trends in precipitation, the dataset needs to be carefully handled based on the physical and dynamical understands the data. Thereby, this paper proposes the following approaches: i) refining and combining major factors (weather radar, terrain, air temperature, and so on) related to precipitation development in order to construct training data for pattern analysis of precipitation; ii) producing predicted precipitation fields based on Convolutional with ConvLSTM. The proposed algorithm was evaluated by rainfall events in 2020. It is outperformed in the magnitude and strength of precipitation, and clearly predicted non-linear pattern of precipitation. The algorithm can be useful as a forecasting tool for preventing severe weather.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.737-746
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• 2008

Recently, NDTs (Non-Destructive Techniques) using electromagnetic(EM) properties are applied to the performance evaluation for RC (Reinforced Concrete) structures. Since nonmetallic materials which are cement-based system have their unique dielectric constant and conductivity, they can be characterized and changed with different mixture conditions like W/C (water to cement) ratios and unit cement weight. In a room condition, cement mortar is generally dry so that porosity plays a major role in EM properties, which is determined at early-aged stage and also be affected by curing condition. In this paper, EM properties (dielectric constant and conductivity) in cement mortar specimens with 4 different W/C ratios are measured in the wide region of 0.2 GHz~20 GHz. Each specimen has different submerged curing period from 0 to 28 days and then EM measurement is performed after 4 weeks. Furthermore, porosity at the age of 28 days is measured through MIP (Mercury Intrusion Porosimeter) and saturation is also measured through amount of water loss in room condition. In order to evaluate the porosity from the initial curing stage, numerical analysis based on the modeling for the behavior in early-aged concrete is performed and the calculated results of porosity and measured EM properties are analyzed. For the convenient comparison with influencing parameters like W/C ratios and curing period, EM properties from 5 GHz to 15 GHz are averaged as one value. For 4 weeks, the averaged dielectric constant and conductivity in cement mortar are linearly decrease with higher W/C ratios and they increase in proportion to the square root of curing period regardless of W/C ratios.

• Convergence Security Journal
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• v.22 no.4
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• pp.3-9
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• 2022

Recently, as the environment of the 4th industrial revolution has arrived, the opening, sharing and convergence of data are actively being achieved in any organization. However, the opening and sharing of data inevitably leads to security vulnerability and there is ambivalence that is a threat that can affect the existence of an organization operated in the 4th industrial revolution environment. Especially security issues in the organization of the military can be a threat to the state, not the military itself, so it is always necessary to maintain a high level of security discipline. In this paper, 14 variables were selected through structural equation model applying theory of planned behavior, deterrence and protection motivation to find out the security level development measures by extracting factors that can affect security level. As a result, the theory of planned behavior that the security knowledge embodied through the usual security regulation education and evaluation affects the behavior was adopted, and the theory of deterrence and protection motivation showed the significance of the rejection level. In addition, it was confirmed that the variables that have the greatest impact on the military security level through the measured values of the three-year security audit were commanders and mental security. In conclusion, in order to improve the security level, it is suggested that security education, definite reward and punishment, and security system upgrading should be firmly established and mental security posture should be secured.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.323-334
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• 2008

Present study examined the functionality of the solitary wave (tsunami) control of the two-rowed porous submerged breakwater by numerical experiments, using a numerical wave tank which is based on the Navier-Stokes equation to explain fluid fields and uses a Volume of Fluid (VOF) method to capture the free water surface. Solitary wave was generated by the internal wave source installed within the computational zone in the numerical wave tank and its wave transformations by structure were compared with those in the previous study. Comparisons with the precious numerical results showed a good agreement. Based on these results, several tow-dimensional numerical modeling investigations of the water fields, including wave transformations, reflection, transmission and energy flux, by the one- and two-rowed permeable submerged breakwater under solitary waves were performed. Even if, it is a research of the limited scope, in case of two-rowed permeable submerged breakwater with $h_0/h=0.925$ ($h_0$ is height of submerged breakwater and h is water depth), the wave height damping in range of $l/L_{eff}>0.4$($L_{eff}$ is effective distance of solitary wave) can reach nearly 60% of the incident wave height. In addition, it is found that reflection coefficient increases nearly 47% and transmission coefficient decreases nearly 18% than one-rowed one. The numerical results revealed that the tow-rowed submerged breakwater can control the incident solitary wave economically and more efficiently than the one-rowed one.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.839-848
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• 2006

Korea has become the 5th country to own and operate the high speed railroad in 2004. However, there were many difficulties until Koreans enjoy the first bullet train service with the average hourly speed of 300km. The high speed railroad requires elevated quality standards differently from the traditional railways. In addition to the technical difficulties, the construction project itself was an unpleasant case with huge delays and cost overruns mainly due to the lack of experiences, deficiency of owner$^{\circ}{\O}$s role, and increase of public resistances triggered by environmental concerns. This paper analyzes the reasons for delays on this mega-project. With respect to the characteristics of the whole project level, it is very complicated/linear project, whose total length is around 412 km with the composition of various sections in the route of the railway which have basically different conditions. For that reason, the analysis is performed in both macro and micro level. First, macroscopic analysis is performed to find critical subdivisions in the railway route that induces the significant delay in the opening due date. Then, microscopic analysis is followed to quantify the causes and effects of delays focused on these critical subdivisions in more detailed way. Finally, this paper provides lessons learned from this project to avoid the decisive delays in performing the similar large-scaled projects.