• Korean Journal of Remote Sensing
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• v.38 no.1
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• pp.57-72
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• 2022

In this paper, we aimed to examine the flowering dates of cherry blossom and the peak dates of maple leaves in South Korea, by the combination of temperature observation data from ASOS (Automated Surface Observing System) and NDVI (Normalized Difference Vegetation Index) from MODIS (Moderate Resolution Imaging Spectroradiometer). The more recent years, the faster the flowering dates and the slower the peak dates. This is because of the impacts of climate change with the increase of air temperature in South Korea. By reflecting the climate change, our statistical models could reasonably predict the plant phenology with the CC (Correlation Coefficient) of 0.870 and the MAE (Mean Absolute Error) of 3.3 days for the flowering dates of cherry blossom, and the CC of 0.805 and the MAE of 3.8 for the peak dates of maple leaves. We could suppose a linear relationship between the plant phenology DOY (day of year) and the environmental factors like temperature and NDVI, which should be inspected in more detail. We found that the flowering date of cherry blossom was closely related to the monthly mean temperature of February and March, and the peak date of maple leaves was much associated with the accumulated temperature. Amore sophisticated future work will be required to examine the plant phenology using higher-resolution satellite images and additional meteorological variables like the diurnal temperature range sensitive to plant phenology. Using meteorological grid can help produce the spatially continuous raster maps for plant phenology.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2158-2165
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• 2023

Marine radioactivity monitoring is critical for taking immediate action in case of unexpected nuclear accidents at nuclear facilities located near coastal areas. Especially when the level of contamination is not predictable, mobile monitoring systems will be useful for wide-area ocean radiation survey and for determination of the level of radioactivity. Here, we used a silicon photomultiplier and a high-efficiency GAGG crystal to fabricate a compact, battery-powered gamma spectroscopy that can be used in an ocean environment. The developed spectroscopy has compact dimensions of 6.5 × 6.5× 8 cm³ and weighs 560 g. We used LoRa, a low-power wireless protocol for communication. Successful data transmission was achieved within 1.4 m water depth. The developed gamma spectroscopy was able to detect radioactivity from a ¹³⁷Cs point source (3.7 kBq) at a distance of 20 cm in water. Moreover, we demonstrated an unmanned radioactivity monitoring system in a real sea by combining unmanned surface vehicle with the developed gamma spectroscopy. A hidden ¹³⁷Cs source (3.07 MBq) was detected by the unmanned system at a distance of 3 m. After successfully testing the developed mobile spectroscopy in an ocean environment, we believe that our proposed system will be an effective solution for mobile real-time marine radioactivity monitoring.

• Knowledge Management Research
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• v.24 no.4
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• pp.63-85
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• 2023

This study aims to identify the primary user group in the growing metaverse space based on the increased interest during the COVID-19 era. It also aims to explore the predictive factors for metaverse adoption. To predict online activities, the study examined user purposes, motivations, and relevant demographic factors as predictive variables through model analysis. The data from the Korean Media Panel Survey were used, and a two-stage analysis with the Heckman two-stage sample selection model was conducted to predict metaverse users. The analysis revealed that the key factors influencing metaverse adoption were offline activities, openness, OTT usage, and purchasing of paid content. Moreover, in the second stage model, openness, gender, and paid content purchases were identified as significant variables for increasing metaverse usage time. These results indicate that understanding metaverse users is essential in the context of the rising interest in online activities during the COVID-19 era and can provide valuable insights for metaverse platform-related companies and developers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.870-877
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• 2020

A suction bucket foundation, especially useful at depths of more than 20m, is a method of construction. The method first places an empty upturned bucket at the target site. Then, the bucket is installed by sucking water or air into it to create negative pressure. For stability, it is crucial to secure the verticality of the bucket. However, inclination by the bucket may occur due to sea-bottom conditions. In general, a repeated intrusion-pulling method is used for securing verticality. However, it takes a long time to complete the job. In this paper, we propose a real-time suction bucket verticality monitoring system. Specifically, the system consists of a sensor unit that collects raw verticality data, a controller that processes the data and wirelessly transmits the information, and a display unit that shows verticality information of a circular steel pipe. The system is implemented using an inclination sensor and an embedded controller. Experimental results show that the proposed system can efficiently measure roll/pitch information with a 0.028% margin of error. Furthermore, we show that the system properly operates in a suction bucket-based model experiment.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.49-54
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• 2020

To attach a stretchable/flexible electrode to something or something to on electrode, conductive adhesives must be stretchable/flexible to suit the properties of the electrode. In particular, conductive adhesive require durability and heat resistance, and unlike conventional adhesives, they should also have conductivity. To this end, Epoxy, which has good strength and adhesion, was selected as an adhesive, and a plasticizer and a reinforcement were mixed instead of a two-liquid material consisting of a conventional theme and a hardener, and a four-liquid material was used to give stretchability/flexibility to high molecules. The conductive filler was selected as silver, a material with low resistance, and for high conductivity, three shapes of Ag particles were used to increase packing density. Conductivity was compared with these developed conductive adhesives and two epoxy-based conductive adhesives being sold in practice, and about 10 times better conductivity results were obtained than products being actually sold. In addition, conductivity, mechanical properties, adhesion and strength were evaluated according to the presence of plasticizers and reinforcement agent. There was also no problem with 60% tensile after 5 minutes of curing at 120℃, and pencil hardness was excellently measured at 6H. As a result of checking the adhesion of electrodes through 3M tape test, all of them showed excellent results regardless of the mixing ratio of binders. After attaching the Cu sheet on top of the electrode through conductive adhesive, the contact resistance was checked and showed excellent performance with 0.3 Ω.

• Journal of Digital Convergence
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• v.12 no.6
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• pp.13-22
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• 2014

This study analyzed the globalization policy of ICT SMEs and ventures using cognitive map analysis and derived the priority to importance about action plans using AHP model, while the globalization paradigm has been rapidly changing in the ICT industry. Empirical results showed that policy tool variables should be needed to develop because policy goal variables are generally presented more than policy tool variables. In addition, this cognitive map could be characterized by a scarcity of feedback loops which means policy landscape for ICT SMEs and ventures' globalization is unilateral rather than cyclical to reach policy goal from policy tools. Another finding is that creative economy policy variable was not observed as policy tool variable but as policy goal variable. This means creative economy can be implemented through support for ICT SMEs and ventures' globalization. Finally, for detailed policy measures, installation of global start-up center, recruiting and utilization of global specialists, revitalization of ICT R&D international collaboration study, enlargement of global investment network, accompanied overseas advance of large enterprises and SMEs are presented in order in terms of the importance of policy priority.

• Journal of the Korea Institute of Building Construction
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• v.16 no.6
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• pp.535-544
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• 2016

Korean government is promoting "K-Smart City" to overseas market which is an integrated solution of construction industry with ICT(Information and Communciations Technologies) industry. Due to nature of Smart City, construction quality and the development quality of the facilities need to be established to improve the overall quality. However, guidelines and regulations to initiate quality control for Smart City are behind the actual demand. This deficiency is bringing quality control for construction and ICT to be controlled separately causing lack of synergy and resulting in overall quality degradation. This research is designed to improve the construction quality of Smart City during its establishment stage by integrating ICT system with on-site construction (Integrated control center and on-site equipment). The adoption of this research to a real Smart City case had resulted in 22% reduction of construction inspection failure (Audit), and also allowed Construction Company to pre-align quality control of all purchased items of ICT Infra that resulted in 18% reduction of nonconformity, thus contributing to an overall quality improvement. This research is expected to be used widely among all construction industry of Smart City.

• Journal of Digital Convergence
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• v.15 no.9
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• pp.35-46
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• 2017

This study aim to figure out the limitation of existing ICT SMEs technology support programs conducted by Government Funded Research Institute. To investigate the limitations of SMEs programs, we conducted Focus Group Interview(FGI) with staff in charge of R&D department of beneficiaries(ICT SMEs). The results of FGI show that SMEs have troubles with the lack of R&D manpower, R&D infrastructure and non-R&D activities. Then, we conducted Delphi survey(derived from FGI) with related field experts to ask the problems and limitations of SMEs programs. The Results of Delphi show that SMEs programs has limitations with avoiding of SMEs support staff, lack of public R&D infrastructure sharing center, incompleteness of policies. Based on the results of FGI and Delphi, we suggest the several ways to improving SMEs programs.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.103-109
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• 2021

About the orthogonal Hadamard matrix announced by Hadamard in France in 1893, Professor Moon Ho Lee newly defined it as Center Weight Hadamard in 1989 and announced it, and discovered the Jacket matrix in 1998. The Jacket matrix is a generalization of the Hadamard matrix. In this paper, we propose a method of obtaining the Symmetric Jacket matrix, analyzing important properties and patterns, and obtaining the Jacket matrix's determinant and Eigenvalue, and proved it using Eigen decomposition. These calculations are useful for signal processing and orthogonal code design. To analyze the matrix system, compare it with DFT, DCT, Hadamard, and Jacket matrix. In the symmetric matrix of Galois Field, the element-wise inverse relationship of the Jacket matrix was mathematically proved and the orthogonal property AB=I relationship was derived.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.2
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• pp.99-104
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• 2016

This paper aims to develop the One-In-One web solutions that can work in PC, tablet, notebook, and smart phone depending on the flow of the ICT times to promote the marketing of the technology. The characteristics of this web solutions can be used to a image viewer system of 3D array type for PC, tablet, notebook, and smart phone. It is implemented in the design of 3D display slide show type. And it is developed an image viewer system, which enables users to use by utilizing the links manner ICT base required by each channel of the image. This is the 3D photo viewer PR solution developed in the way that anyone can use easily without the knowledge of programming in various areas such as public relations, business, and education.