• Journal of the Korean Applied Science and Technology
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• v.40 no.2
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• pp.223-232
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• 2023

Oxidative stress plays a significant role in the pathogenesis of various skin conditions, resulting in cellular and tissue damage that can contribute to the development of skin tone unevenness, roughness and wrinkles. In this study, we found that Trifolium pratense L. extract (TE) attenuated oxidative-induced damage in HaCaT cells and elucidated the underlying molecular mechanism. Our finding demonstrated that TE effectively protected HaCaT cells against H₂O₂-induced cell death by inhibiting caspase-3 activation, downregulating Bax and upregulating Bcl-2, and attenuating the activation of three mitogen-activated protein kinases (MAPKs). Our results suggest that TE has remarkable cytoprotective properties against oxidative damage in HaCaT cells and could serve as a complementary or alternative approach to prevent and treat skin damage.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.235-243
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• 2002

This study was designed to examine the ability of the bovine (MII) oocytes cytoplasm to support several mitotic cell cycles under the direction of differentiated somatic cell nuclei of bovine, porcine, mouse and human. Bovine GV oocytes were matured in TCM-199 supplemented with 10% FBS. At 20h after IVM, recipient oocytes were stained with 5 $\mu\textrm{g}$/$m\ell$ Hoechst and their 1st polar body (PB) and MII plate were removed by enucleation micropipette under UV filter. Ear skin samples were obtained by biopsy from an adult bovine, porcine, mouse and human and cultured in 10% FBS added DMEM. Individual fibroblast was anlaysed chromosome number to confirm the specificity of species. Nuclear transferred (NT) units were produced by electrofusion of enucleated bovine oocytes with individual fibroblast. The reconstructed embryos were activated in 5 $\mu$M ionomycin for 5 min followed by 1.9 mM 6-dimethylaminopurine (DMAP) in CR1aa for 3 h. And cleaved NT embryos were cultured in CR1aa medium containing 10% FBS on monolayer of bovine cumulus cell for 8 days. Also NT embryo of 4~8 cell stage was analysed chromosome number to confirm the origin of nuclear transferred somatic cell. The rates of fusion between bovine recipient oocytes and bovine, porcine, mouse and human somatic cells were 70.2%, 70.2%, 72.4% and 63.0%, respectively. Also, their cleavage rates were 60.6%, 63.7%, 54.1% and 62.7%, respectively, there were no differences among them. in vitro development rates into morula and blastocyst were 17.5% and 4.3% in NT embryos from bovine and human fibroblasts, respectively. But NT embryos from porcine and mouse fibroblasts were blocked at 16~32-cell stage. The chromosome number in NT embryos from individual fibroblast was the same as chromosome number of individual species. These results show that bovine MII oocytes cytoplasm has the ability to support several mitotic cell cycles directed by newly introduced nuclear DNA.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.305-311
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• 2013

Purpose: This study was conducted to evaluate the effect of prescription of overcorrection (-) lens, which is the one of the non-surgical treatments, on stereo-acuity and angle of deviation in intermittent exotropia. Methods: Twenty four children with intermittent exotropia were enrolled from October 2011 to December 2011. The angle of deviation(${\Delta}$), stereo-acuity (arcsec), monocular and binocular visual acuity (BVA, LogMAR), control of exodeviation and fusional ability using Worth 4 dot test were evaluated at near (33 cm) and far (6 m), under the overcorrecting (-)lens of -1.00, -.00, and -.00 D. Results: As a baseline finding, the angle of exodeviation was $20.9{\pm}9.7$ at near and $23.0{\pm}7.5$ at far. The angle of exodeviation at near decreased to $18.5{\pm}10.0$ (p<0.01), $15.8{\pm}9.0$ (p<0.01), $14.0{\pm}9.1$ (p<0.01) compared with baseline angle of exodeviation at near, as increasing diopters of (-) lens from -.00 D, -2.00 D and -.00 D, respectively. The angle of exodeviation at far also decreased to $21.4{\pm}5.2$ (p=0.01), $19.6{\pm}6.3$ (p<0.01) compared with baseline, as increasing minus lens from -2.00 D and -3.00 D, respectively. However, BVA, control of exodeviation, fusional ability and stereo-acuity showed no significant decrease despite of increasing diopters of (-)lens. Conclusions: The prescription of overcorrection (-)lens is an effective therapeutic method in intermittent exotropia which can reduce the near and far angle of exodeviation, and binocular visual acuity and stereo-acuity maintained without significant decrease despite of application of overcorrection (-)lens.

• Clean Technology
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• v.28 no.4
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• pp.309-315
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• 2022

Research was conducted to derive the optimal operation conditions and the optimal cathode for using a DSA electrode as an anode to minimize electrode consumption during the removal of nitrogen from wastewater by the electro-chemical method. Of the various electrodes tested as cathodes, brass was determined to be the optimal electrode. It had the highest NO₃-N removal rate and the lowest concentration of residual NH₃-N, a by-product when Cl is present in the solution. Investigating the effect of current density found that when the initial concentration of NO₃-N was 50 mg L^-1, the optimal current density was 15 mA cm^-2. In addition, current densities above 15 mA cm^-2 did not significantly affect the NO₃-N removal rate. The effect of electrolytes on removing NO₃-N and minimizing NH₃-N was investigated by using Na₂SO₄ and NaCl as electrolytes and varying the reaction times. When Na₂SO₄ and NaCl are mixed at a ratio of 1.0 g L^-1 to 0.5 g L^-1 and reacted for 90 min at a current density of 15 mA cm^-2 and an initial NO₃-N concentration of 50 mg L^-1, the removal rate of NO₃-N was about 48% and there was no residual NH₃-N. On the other hand, when using only 1.5 g L^-1 of NaCl as an electrolyte, the removal rate of NO₃-N was the highest at about 55% and there was no residual NH₃-N.

• Journal of the Korean Geotechnical Society
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• v.39 no.5
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• pp.51-63
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• 2023

Numerical analysis was conducted to determine the effect of soil behavior by thawing and freezing of seasonal frozen soil on pile foundations. The analysis was performed using the finite element method (FEM) to simulate soil-pile interaction based on the atmosphere temperature change. Thermomechanical coupled modeling using FEM was applied with the temperature-dependent nonlinear properties of the frozen soil. The analysis model cases were applied to the MCR and HDP models to simulate the elastoplastic behavior of soil. The numerical analysis results were analyzed and compared with various conditions having different length and width sizes of the pile. The results of the numerical analysis showed t hat t he HDP model was relat ively passive, and t he aspect and magnit ude of t he bearing capacit y and displacement of the pile head were similar depending on the length and width of the pile conditions. The vertical displacement of the pile head by thawing and freezing of the ground showed a large variation in displacement for shorter length conditions. In the MCR model, the vertical displacement appeared in the maximum thaw settlement and frost heaving of 0.0387 and 0.0277 m, respectively. In the HDP model, the vertical displacement appeared in the maximum thaw settlement and frost heaving of 0.0367 and 0.0264 m, respectively. The results of the pile bearing capacity for the two elastoplastic models showed a larger difference in the width condition than the length condition of the pile, with a maximum of about 14.7% for the width L condition, a maximum of about 5.4% for M condition, and a maximum of about 5.3% for S condition. The significance of the effect on the displacement of the pile head and the bearing capacity depended on the pile-soil contact area, and the difference depended on the presence or absence of an active layer in the soil and its thickness.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.555-560
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• 2023

Conventional aqueous amine-based CO₂ capture has a problem in that a large amount of renewable energy is required for CO₂ stripping and solvent regeneration in its industrial applications. This work proposes a water-lean absorbent that can reduce regeneration energy by lowering the water content in the absorbent with high absorption capacity for CO₂. To this purpose, this water-lean solvent introduced NMP (N-methyl-2-pyrrolidone), which has a higher physical solubility in CO₂ and a low specific heat capacity comparing to water, along with 3-methylaminopropylamine (MAPA), a diamine, into the absorbent. The circulating absorption capacity and absorption rate for CO₂ of this water-lean solvent were measured using a packed tower. When NMP was added to the absorbent, the absorption rate was improved. In the case of the absorbent containing 2.5M MAPA was used, the maximum circulating absorption capacity was obtained when 10 wt% of NMP was included in absorbent. The overall mass transfer coefficient increased as the concentration of NMP increased. However, at loading values higher than 0.5, the increment in mass transfer coefficient decreased as the concentration of NMP increased. When the lean loading value is low, the mass transfer resistance due to viscosity of the absorbent is low, so the overall mass transfer coefficient increases with the addition of NMP. However, as the lean loading value increases, the viscosity of the absorbent increases, and the diffusivity of CO₂ and MAPA decreases, resulting in sharply decreasing of the overall mass transfer coefficient.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.241-254
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• 2011

Financial time-series forecasting is one of the most important issues because it is essential for the risk management of financial institutions. Therefore, researchers have tried to forecast financial time-series using various data mining techniques such as regression, artificial neural networks, decision trees, k-nearest neighbor etc. Recently, support vector machines (SVMs) are popularly applied to this research area because they have advantages that they don't require huge training data and have low possibility of overfitting. However, a user must determine several design factors by heuristics in order to use SVM. For example, the selection of appropriate kernel function and its parameters and proper feature subset selection are major design factors of SVM. Other than these factors, the proper selection of instance subset may also improve the forecasting performance of SVM by eliminating irrelevant and distorting training instances. Nonetheless, there have been few studies that have applied instance selection to SVM, especially in the domain of stock market prediction. Instance selection tries to choose proper instance subsets from original training data. It may be considered as a method of knowledge refinement and it maintains the instance-base. This study proposes the novel instance selection algorithm for SVMs. The proposed technique in this study uses genetic algorithm (GA) to optimize instance selection process with parameter optimization simultaneously. We call the model as ISVM (SVM with Instance selection) in this study. Experiments on stock market data are implemented using ISVM. In this study, the GA searches for optimal or near-optimal values of kernel parameters and relevant instances for SVMs. This study needs two sets of parameters in chromosomes in GA setting : The codes for kernel parameters and for instance selection. For the controlling parameters of the GA search, the population size is set at 50 organisms and the value of the crossover rate is set at 0.7 while the mutation rate is 0.1. As the stopping condition, 50 generations are permitted. The application data used in this study consists of technical indicators and the direction of change in the daily Korea stock price index (KOSPI). The total number of samples is 2218 trading days. We separate the whole data into three subsets as training, test, hold-out data set. The number of data in each subset is 1056, 581, 581 respectively. This study compares ISVM to several comparative models including logistic regression (logit), backpropagation neural networks (ANN), nearest neighbor (1-NN), conventional SVM (SVM) and SVM with the optimized parameters (PSVM). In especial, PSVM uses optimized kernel parameters by the genetic algorithm. The experimental results show that ISVM outperforms 1-NN by 15.32%, ANN by 6.89%, Logit and SVM by 5.34%, and PSVM by 4.82% for the holdout data. For ISVM, only 556 data from 1056 original training data are used to produce the result. In addition, the two-sample test for proportions is used to examine whether ISVM significantly outperforms other comparative models. The results indicate that ISVM outperforms ANN and 1-NN at the 1% statistical significance level. In addition, ISVM performs better than Logit, SVM and PSVM at the 5% statistical significance level.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.249-261
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• 2020

Coastal monitoring using multiple platforms/sensors is a very important tools for accurately understanding the changes in offshore marine environment and disaster with high temporal and spatial resolutions. However, integrated observation studies using multiple platforms and sensors are insufficient, and none of them have been evaluated for efficiency and limitation of convergence. In this study, we aimed to suggest an integrated observation method with multi-remote sensing platform and sensors, and to diagnose the utility and limitation. Integrated in situ surveys were conducted using Rhodamine WT fluorescent dye to simulate various marine disasters. In September 2019, the distribution and movement of RWT dye patches were detected using satellite (Kompsat-2/3/3A, Landsat-8 OLI, Sentinel-3 OLCI and GOCI), unmanned aircraft (Mavic 2 pro and Inspire 2), and manned aircraft platforms after injecting fluorescent dye into the waters of the South Sea-Yeosu Sea. The initial patch size of the RWT dye was 2,600 ㎡ and spread to 62,000 ㎡ about 138 minutes later. The RWT patches gradually moved southwestward from the point where they were first released,similar to the pattern of tidal current flowing southwest as the tides gradually decreased. Unmanned Aerial Vehicles (UAVs) image showed highest resolution in terms of spatial and time resolution, but the coverage area was the narrowest. In the case of satellite images, the coverage area was wide, but there were some limitations compared to other platforms in terms of operability due to the long cycle of revisiting. For Sentinel-3 OLCI and GOCI, the spectral resolution and signal-to-noise ratio (SNR) were the highest, but small fluorescent dye detection was limited in terms of spatial resolution. In the case of hyperspectral sensor mounted on manned aircraft, the spectral resolution was the highest, but this was also somewhat limited in terms of operability. From this simulation approach, multi-platform integrated observation was able to confirm that time,space and spectral resolution could be significantly improved. In the future, if this study results are linked to coastal numerical models, it will be possible to predict the transport and diffusion of contaminants, and it is expected that it can contribute to improving model accuracy by using them as input and verification data of the numerical models.

• Journal of the International Relations & Interdisciplinary Education
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• v.3 no.1
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• pp.51-75
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• 2023

Relying on disciplinary competitions to enhance college students' innovation and entrepreneurship is one of the specific paths to explore the reform of innovation and entrepreneurship education in colleges and universities. This paper conducts an empirical study on the practice of disciplinary competitions among Chinese university students, the problems of innovation and entrepreneurship education in Chinese universities and the impact of disciplinary competitions on innovation and entrepreneurship among Chinese university students, using university students in Chinese universities as the respondents. The data collected online and offline were analysed using SPSS26 statistical software. The results of the analysis show that Chinese university students show a high level of interest in innovation and entrepreneurship competitions and that there are some differences in the level of interest in innovation and entrepreneurship competitions among university students of different academic levels. More than half of Chinese university students have participated in innovation and entrepreneurship competitions and the initiative of participating in innovation and entrepreneurship competitions varies by grade. The biggest problem facing innovation and entrepreneurship education in schools is the lack of professional innovation and entrepreneurship teachers, followed by the lack of guidance on innovation and entrepreneurship-related policies, and the unreasonable reward system, which makes teachers and students less motivated to innovate and entrepreneurship. Through one-dimensional linear regression analysis, it is found that the degree of attention to innovation and entrepreneurship among college students affects college students' entrepreneurial awareness and entrepreneurial practice; the degree of initiative of college students' innovation and entrepreneurship competition affects college students' entrepreneurial effect; and the degree of initiative of college students' innovation and entrepreneurship competition affects college students' entrepreneurial practice.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.321-335
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• 2020

Given that with the development of the 4th industry, interest and desire for smart cities are gradually increasing and related technologies are developed as a way to strengthen urban competitiveness by utilizing big data, information and communication technology, IoT, M2M, and AI, the purpose of this study is to find out how to achieve this goal on the premise of the idea of smart well fair city. In other words, the purpose is to devise a smart well-fair city in the care area, such as health care, medical care, and welfare, and see if it is feasible. With this recognition, the paper aimed to review the concept and scope of smart city, the discussions that have been made so far and the issues or limitations on its connection to social security and social welfare, and based on it, come up with the concept of welfare city. As a method of realizing the smart welfare city, the paper reviewed characteristics and features of a social security platform as well as the applicability of smart city, especially care services. Furthermore, the paper developed discussions on the standardization of the city in terms of political and institutional improvements, utilization of personal information and public data as well as ways of institutional improvement centering on social security information system. This paper highlights the importance of implementing the digitally based community care and smart welfare city that our society is seeking to achieve. With regard to the social security platform based on behavioral design and the 7 principles(6W1H method), the present paper has the limitation of dealing only with smart cities in the fields of healthcare, medicine, and welfare. Therefore, further studies are needed to investigate the effects of smart cities in other fields and to consider the application and utilization of technologies in various aspects and the corresponding impact on our society. It is expected that this paper will suggest the future course and vision not only for smart cities but also for the social security and welfare system and thereby make some contribution to improving the quality of people's lives through the requisite adjustments made in each relevant field.