• KIPS Transactions on Computer and Communication Systems
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• v.12 no.10
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• pp.299-308
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• 2023

As the spectrum shortage problem has accelerated by the emergence of various services, New Radio-Unlicensed (NR-U) has appeared, allowing users who communicated in licensed bands to communicate in unlicensed bands. However, NR-U network users reduce the performance of Wi-Fi network users who communicate in the same unlicensed band. In this paper, we aim to simultaneously maximize the fairness and throughput of the unlicensed band, where the NR-U network users and the WiFi network users coexist. First, we propose an optimal power allocation scheme based on Monte Carlo Policy Gradient of reinforcement learning to maximize the sum of rates of NR-U networks utilizing rate-splitting multiple access in unlicensed bands. Then, we propose a channel occupancy time division algorithm based on sequential Raiffa bargaining solution of game theory that can simultaneously maximize system throughput and fairness for the coexistence of NR-U and WiFi networks in the same unlicensed band. Simulation results show that the rate splitting multiple access shows better performance than the conventional multiple access technology by comparing the sum-rate when the result value is finally converged under the same transmission power. In addition, we compare the data transfer amount and fairness of NR-U network users, WiFi network users, and total system, and prove that the channel occupancy time division algorithm based on sequential Raiffa bargaining solution of this paper satisfies throughput and fairness at the same time than other algorithms.

• Journal of Korean Society of Archives and Records Management
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• v.23 no.4
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• pp.137-157
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• 2023

The scale of research and development (R&D) investment is increasing to strengthen national competitiveness through technological innovation, leading to an increased interest in investment efficiency. In records management, the National Archives of Korea has been leading the national research and development project since 2008. Accordingly, this study analyzed R&D projects in records management regarding implementing organization, performance or outcomes, and subjects, targeting 111 National Archives of Korea contract research projects from 2008 to 2022. The analysis showed that small and medium-sized enterprises (SMEs) were the most likely to conduct research, the majority of the research outcomes were academic publications, and there were some discrepancies between the reported performance in research and the actual performance. In terms of research subjects, the most common type of records are paper or print documents, establishing an electronic management system among the National Archives' works. In terms of the frequency of keywords in the records management process and research projects, it was found that research was mainly conducted on "preservation." Meanwhile, only 10 cases, or 9% of the 111 projects, were found to be relevant in terms of utilizing big data and developing intelligent technologies related to digital transformation. Therefore, the effectiveness of the R&D project must be improved through follow-up management of the results even after the research project is completed. In addition, in terms of research topics, it was identified that aside from "preservation," studies focusing on "transfer," "classification," "evaluation," and "collection," as well as research that responds to digital transformation, are needed.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.3
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• pp.245-256
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• 2022

The purpose of this study is to provide comprehensive insights on the current research trends in entrepreneurship based on topic modeling and keyword co-occurrence analysis. This study queried Web of Science database with 'entrepreneurship' and collected 14,953 research articles between 2002 and 2021. The study used R program for topic modeling and VOSviewer program for keyword co-occurrence analysis. The results of this study are as follows. First, as a result of keyword co-occurrence analysis, 5 clusters divided: entrepreneurship and innovation cluster, entrepreneurship education cluster, social entrepreneurship and sustainability cluster, enterprise performance cluster, and knowledge and technology transfer cluster. Second, as a result of the topic modeling analysis, 12 topics found: start-up environment and economic development, international entrepreneurship, venture capital, government policy and support, social entrepreneurship, management-related issues, regional city planning and development, entrepreneurship research, and entrepreneurial intention. Finally, the study identified two hot topics(venture capital and entrepreneurship intention) and a cold topic(international entrepreneurship). The results of this study are useful to understand current research trends in entrepreneurship research and provide insights into research of entrepreneurship.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.517-525
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• 2023

The emergence and spread of multidrug-resistant Pseudomonas aeruginosa (MRPA) have become a serious problem worldwide. The involvement of metallo-β-lactamases (MBLs) in inducing carbapenem resistance is particularly acute. However, unlike other members of the Enterobacteriaceae genus, new clones of P. aeruginosa are constantly emerging and rapidly replacing previously prevalent dominant clones. Therefore, this study aimed to perform antimicrobial resistance gene analysis, integron gene cassette analysis using DNA sequencing, and plasmid transfer analysis by conjugation to investigate the antimicrobial resistance dynamics of 18 P. aeruginosa strains isolated from various medical samples at a general hospital in Busan from September 2017 to September 2019. All 18 strains showed extensively drug-resistant (XDR) phenotype and were resistant to most antibiotics, except colistin (100%) but were susceptible to aztreonam (22.2%) and ceftazidime (16.6%). Approximately 66.7% of the strains had Class 1 integrons showing various antimicrobial resistances. Notably, IMP-6 ST235 (66.7%), VIM-2 ST357 (16.7%), and IMP-1 ST446(16.7%) were identified. The identification of IMP-1-producing ST446, previously unreported in Korea, is noteworthy considering the emergence and prevalence of another MRPA high-risk clone.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.3
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• pp.169-189
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• 2024

In the current work, a series of three-dimensional finite element analyses have been carried out to understand the behaviour of pre-existing single piles and pile groups to adjacent Shield TBM tunnelling by considering various reinforcement conditions. The numerical modelling has analysed the effect of the pile cutting, ground reinforcement and pile cap reinforcement. The analyses concentrate on the ground settlements, the pile head settlements, the axial pile forces and the shear stress transfer mechanism at the pile-soil interface. In all cases of the pile tips supported by weathered rock, the distributions of shear stresses presented a similar trend. Also, when the pile tips were cut, tensile forces or compressive forces were induced on the piles depending on the relative positions of the piles. Furthermore, when the pile tips are supported by weathered rock, approximately 70% of the load is supported by surface friction, and only the remaining 30% is supported by the pile tip. Furthermore the final settlement of the piles without reinforcement showed approximately 70% more settlement than the piles for which ground reinforcement is considered. It has been found that the ground settlements and the pile settlements are heavily affected by the pile cutting and reinforcement conditions. The behaviour of the single pile and group piles, depending on the pile cutting, conditions of ground and pile cap reinforcement, has been extensively examined and analysed by considering the key features in great details.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.2
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• pp.1-15
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• 2002

Atmospheric aerosols interact with sunlight and affect the global radiation balance that can cause climate change through direct and indirect radiative forcing. Because of the spatial and temporal uncertainty of aerosols in atmosphere, aerosol characteristics are not considered through GCMs (General Circulation Model). Therefor it is important physical and optical characteristics should be evaluated to assess climate change and radiative effect by atmospheric aerosols. In this study GMS-5 satellite data and surface measurement data were analyzed using a radiative transfer model for the Yellow Sand event of April 7~8, 2000 in order to investigate the atmospheric radiative effects of Yellow Sand aerosols, MODTRAN3 simulation results enable to inform the relation between satellite channel albedo and aerosol optical thickness(AOT). From this relation AOT was retreived from GMS-5 visible channel. The variance observations of satellite images enable remote sensing of the Yellow Sand particles. Back trajectory analysis was performed to track the air mass from the Gobi desert passing through Korean peninsular with high AOT value measured by ground based measurement. The comparison GMS-5 AOT to ground measured RSR aerosol optical depth(AOD) show that for Yellow Sand aerosols, the albedo measured over ocean surfaces can be used to obtain the aerosol optical thickness using appropriate aerosol model within an error of about 10%. In addition, LIDAR network measurements and backward trajectory model showed characteristics and appearance of Yellow Sand during Yellow Sand events. These data will be good supporting for monitoring of Yellow Sand aerosols.

• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.365-371
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• 2012

The radiation therapy treatment technique is developed from 3D-CRT, IMRT to Tomotherapy. and these three technique was most widely using methods. We find out a comparison normal tissue doses and tumor dose of 3D-CRT, IMRT(Linac Based), and Tomotherapy on Head and Neck Cancer. We achieved radiological image used the Human model phantom (Anthropomorphic Phantom) and it was taken CT simulation (Slice Thickness : 3mm) and GTV was nasopharngeal region and PTV(including set-up margin) was GTV plus 2mm area. and transfer those images to the radiation planning system (3D-CRT - ADAC-Pinnacle3, Tomotherapy - Tomotherapy Hi-Art System). The prescription dose was 7020 cGy and measuring PTV's dose and nomal tissue (parotid gland, oral cavity, spinal cord). The PTV's doses was Tomotherapy, Linac Based - IMRT, 3D-CRT was 6923 cGy, 6901 cGy and 6718 cGy its dose value was meet TCP because its value was up to the 95% based on 7020 cGy, Nomal tissue (parotid gland, oral cavity, spinal cord) was 1966 cGy(Tomotherapy), 2405 cGy(IMRT), 2468 cGy(3D-CRT)[parotid gland], 2991 cGy(Tomotherapy), 3062 cGy(IMRT), 3684 cGy (3D-CRT)[oral cavity], 1768 cGy(Tomotherapy), 2151 cGy(IMRT), 4031 cGy(3D-CRT)[spinal cord] its value did not exceeded NTCP. All the treatment techniques are equated with tumor and nomal tissue doses. The 3D-CRT was worse than other techniques on dose distribution, but it is reasonable in terms of TCP and NTCP baseline Tomotherapy, IMRT -dose distribution was relatively superior- was hard to therapy to claustrophobic patients and patients with respiratory failure. Particularly, in case on Tomotherapy, it take MVCT before treatment so dose measurement will be unnecessary radiation exposure to patients. Conclusion, Tomotherapy was the best treatment technique and 2nd was IMRT, and 3rd 3D-CRT. But applicable differently depending on the the patient's condition even though dose not matter.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.07b
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• pp.37-54
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• 2003

It has been recognized that the hen. like its mammalian counterparts. provides young chicks with antibodies as protection against hostile invaders. This system facilitates the transfer of specific antibodies from serum to egg yolk. and provides a supply of antibodies called immunoglobulin Y(IgY) to the developing embryo and the hatched chick. The protection against pathogens that the relatively immuno-incompetent newly hatched chick has. is through transmission of antibodies from the mother via the egg. Egg yolk. therefore. can be loaded with a large amount of IgY against pathogens which can immobilize the existing or invading pathogens during the embryo development or in day-old chicks. Thus. the immunization of laying hens to various pathogens results in production of different antigen-specific IgY in eggs. Egg yolk contains 8~20 mg of immunoglobulins (IgY) per $m\ell$ or 136~340 mg per yolk suggesting that more than 30 g of IgY can be obtained from one immunized hen in a year. By immunizing laying hens with antigens and collecting IgY from egg yolk. low cost antibodies at less than ＄10 per g compared to more than ＄20.000 per g of mammalian IgG can be obtained. This IgY technology opens new potential market applications in medicine. public health veterinary medicine and food safety. A broader use of IgY technology could be applied as biological or diagnostic tool. nut-raceutical or functional food development. oral-supplementation for prophylaxis. and as pathogen-specific antimicrobial agents for infectious disease control. This paper has emphasized that when IgY-loaded chicken eggs are produced and consumed. the specific antibody binds. immobilizes and consequently reduces or inhibits the growth or colony forming abilities of microbial pathogens. This concept could serve as an alternative agent to replace the use of antibiotics. since today. more and more antibiotics are less effective in the treatment of infections. due to the emergence of drug-resistant bacteria.

• Clean Technology
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• v.26 no.2
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• pp.102-108
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• 2020

In recent years, packed column has been widely used in separation processes, such as absorption, desorption, distillation, and extraction, in the petrochemical, fine chemistry, and environmental industries. Packed column is used as a contacting facility for gas-liquid and liquid-liquid systems filled with random packed materials in the column. Packed column has various advantages such as low pressure drop, economical efficiency, thermally sensitive liquids, easy repairing restoration, and noxious gas treatment. The performance of a packed column is highly dependent on the maintenance of good gas and liquid distribution throughout a packed bed; thus, this is an important consideration in a design of packed column. In this study, hydraulic pressure drop, hold-up as a function of liquid load, and mass transfer in the air, air/water, and air-NH₃/water systems were studied to find the geometrical characteristic for raschig super-ring experiment dry pressure drop. Based on the results, design factors and operating conditions to handle noxious gases were obtained. The dry pressure drop of the random packing raschig super-ring was linearly increased as a function of gas capacity factor with various liquid loads in the Air/Water system. This result is lower than that of 35 mm Pall-ring, which is most commonly used in the industrial field. Also, it can be found that the hydraulic pressure drop of raschig super-ring is consistently increased by gas capacity factor with various liquid loads. When gas capacity factor with various liquid loads is increased from 1.855 to 2.323 kg^-1/2 m^-1/2 S^-1, hydraulic pressure drop increases around 17%. Finally, the liquid hold-up related to packing volume, which is a parameter of specific liquid load depending on gas capacity factor, shows consistent increase by around 3.84 kg^-1/2 m^-1/2 S^-1 of the gas capacity factor. However, liquid hold-up significantly increases above it.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.604-609
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• 2003

In order to investigate the transfer rate of calcium into rice and the effect of soaking conditions-temperature (20, 30, 40, 50 and $60^{\circ}C$, $X_1$), calcium concentration of soaking solution (0, 250, 500, 750 and 1000 mg/L, $X_2$) and soaking time (5, 10, 15, 20 and 25 min, $X_3$), moisture absorption rate, hardness and calcium content of rice after soaking were analyzed. When the soaking temperature and time were increased the moisture absorption rate also increased (p<0.01). Quadratic and interaction effects on the moisture absorption rate among variables were highly significant, within 5%. The predictive model for moisture absorption rate $(Y_1)$ was as follows: $Y=16.14+0.78X_1+1.24X_3-0.23X_1{^2}+0.14X_2{^2}-0.42X_3X_1-0.38X_3{^2}\;(R^2=0.9123)$. Hardness was decreased as soaking time and temperature increased. Calcium contents of soaked rice increased as temperature, the calcium concentration of soaking solution and soaking time were increased (p<0.01). Also the interactive effect between soaking time and calcium concentration of soaking solution was high. The predictive model for calcium content $(Y_3)$ was as follows: $Y_3=470.80+110.87X_1+123.47X_2+52.29X_3-7.42X_1{^2}-14.87X_2{^2}-9.49X_3X_2-20.57X_3{^2}\;(R^2=0.9840)$. From the results in this study, if adults and children take 400 g of calcium enriched rice with 600 mg/kg and $700{\sim}900\;mg/kg$, respectively, they can expect to take more calcium than the recommended intake without other calcium reinforcing agents.