• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.611-620
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• 2020

Although process-based models have been a preferred approach for modeling freshwater aquatic systems over extended time intervals, the increasing utility of data-driven models in a big data environment has made the data-driven models increasingly popular in recent decades. In this study, international peer-reviewed journals for the relevant fields were searched in the Web of Science Core Collection, and an extensive literature review, which included total 2,984 articles published during the last two decades (2000-2020), was performed. The review results indicated that the rate of increase in the number of published studies using data-driven models exceeded those using process-based models since 2010. The increase in the use of data-driven models was partly attributable to the increasing availability of data from new data sources, e.g., remotely sensed hyperspectral or multispectral data. Consistently throughout the past two decades, South Korea has been one of the top ten countries in which the greatest number of studies using the data-driven models were published. Among the major data-driven approaches, i.e., artificial neural network, decision tree, and Bayesian model, were illustrated with case studies. Based on the review, this study aimed to inform the current state of knowledge regarding the biogeochemical water quality and ecological models using data-driven approaches, and provide the remaining challenges and future prospects.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.73-78
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• 2009

Objectives : In this study, we studied the effect of Pinellia Ternata (PT) on regulatory T cells and CD3+CCR3+ Th2 cells number in asthma model mice. Methods : All mice were immunized on two different days (21 days and 7 days before inhalational exposure) by i.p. injections of 0.2 $m\ell$ alum-precipitated Ag containing 100 ${\mu}g$ of OVA bound to 4 mg of aluminum hydroxide in PBS. Seven days after the second sensitization, mice were exposed to aerosolized ovalbumin for 30 min/day on 3 days/week for 12 weeks(at a flow rate of 250 L/min, 2.5％ ovalbumin in normal saline) and PT (400, 200 mg/kg) were orally administered 3 times a week for 8 weeks. After C57BL/6 mice were orally given of PT, the percentages, cell numbers, phenotype and function of CD4+CD25+Treg cells were determined by flow cytometry. Results : The cell numbers of CD4+CD25+Treg cell subsets were markedly increased in PT treated mice as reported. However, PT significantly reduced the CD3+CCR3+ Th2 cells in PBMC and lung of mice. Conclusions : These results indicate that PT has a deep inhibitory effect on asthma model mice by increase the number of regulatory T cells, and by reducing CD3+CCR3+ Th2 cells.

• The Korea Journal of Herbology
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• v.24 no.1
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• pp.79-88
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• 2009

Objectives : It has been recently shown that Piperis Longi Fructus (PLF) is involved in the reduction of eosinophil recruitment and production of Th2 cytokines in vivo. However, the main therapeutic mechanisms of PLF remains a matter of considerable debate. To investigate the therapeutic mechanisms of PLF, we examined the influence of PLF on regulatory T cells number, IgE, histamine production in vivo and Th1/Th2 cytokine balance in vitro. Methods : All mice were immunized on two different days (21 days and 7 days before inhalational exposure) by i.p. injections of 0.2 $m\ell$ alum-precipitated Ag containing 100 ${\mu}g$ of OVA bound to 4 mg of aluminum hydroxide in PBS. Seven days after the second sensitization, mice were exposed to aerosolized ovalbumin for 30 min/day on 3 days/week for 12 weeks(at a flow rate of 250 L/min, 2.5％ ovalbumin in normal saline) and PLF (150 mg/kg) were orally administered 3 times a week for 8 weeks. Splenocytes from C57BL/6 mice at 8 weeks of age were stimulated with anti-CD3 (1 mg/ml) plus anti-CD28 (1 mg/ml) antibody for 48hrs. IL-4 and IFN-$\gamma$ in the culture supernatants were measured by ELISA Results : The suppressive effects of PLF on asthma model were demonstrated by the increase the number of regulatory T cells and by reducing IgE, histamine production in vivo and modulation of Th1/Th2 cytokine balance. Conclusions : These results indicate that PLF has a deep inhibitory effects on asthma model mice by increase the number of regulatory T cells, and by reducing IgE, histamine production.

• Development and Reproduction
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• v.11 no.1
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• pp.49-54
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• 2007

Ethane 1,2-dimethane sulfonate(EDS), a toxin which specifically kills Leydig cells(LC), has been widely used to prepare the reversible testosterone(T) depletion rat model. In the present study, we monitored the gene expression profiles of pituitary gonadotropins, LH and FSH, up to 7 weeks after EDS injection. Adult male Sprague-Dawley rats($300{\sim}350\;g$ B.W.) were injected with a single dose of EDS(75 mg/kg i.p.) and sacrificed on weeks 0, 1, 2, 3, 4, 5, 6 and 7. Total RNAs were purified from each pituitary, and the message levels of common alpha subunit($C{\alpha}$) of pituitary glycoprotein hormones, LH beta subunit($LH{\beta}$), FSH beta subunit($FSH{\beta}$) and GnRH receptor(GnRH-R) were evaluated by semi-quantitative RT-PCRs. The message levels of $C{\alpha}$ increased sharply during weeks 1-4, then return to the control level on week 5. The mRNA levels of $LH{\beta}$ were elevated after week 2, reached the peak at week 4, then declined to the control level after week 5. The message levels of $FSH{\beta}$ were elevated after week 2, reached the peak at week 3, then declined to the nadir at week 5. Similarly, the mRNA levels of GnRH-R were elevated after week 2, reached the peak at week 3, then gradually declined to the control level after week 5. The present study indicated that EDS treatment could induce reversible alterations in the transcriptional activities of gonadotropin subunits and GnRH-R in the anterior pituitary from male rats. EDS injection model might be useful to understand the mechanism of hormonal regulation of hypothalamus- pituitary neuroendocrine axis in male rats.

• Journal of Life Science
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• v.19 no.1
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• pp.21-33
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• 2009

In this study, we investigated the effect of Rhei Rhizoma (RR; 大黃) water extract on gene expression in a hypoxia model of cultured rat hippocampal neurons. RR water extract $(2.5{\mu}g/ml)$ was added to the culture media on day 10 in vitro (DIV10), and a hypoxic shock (2% $O_2$/5% $CO_2$, $37^{\circ}C$, 3 h) was given on DIV13. After maintaining the cultures in normoxia for 24 hr, total RNA was isolated and used for microarray analysis. The MA-plot indicated that most genes were up- or downregulated within 2-fold. There were more downregulated genes (725 ea) than upregulated ones (472 ea) when larger than Global M value 0.2 (i.e., >15% increase) or smaller than Global M value -0.2 (i.e., >15% decrease) were considered. Antiapoptosis genes such as Tegt (2.4-fold), Nfkb1 (2.4-fold) Veg (1.8-fold), Ngfr (1.6-fold) were upregulated, while pro-apoptosis genes such as Bad (-64%), Cstb (-66%) were downregulated. Genes for combating environmental stress (stress response genes) such as Defb3 (2.7-fold), Cygb (2.2-fold), Ahsg (2.18-fold), Alox5 (2-fold) were upregulated. Genes for cell proliferation (cell cycle-related genes) such as Erbb2 (1.84-fold), Mapk12 gene (1.8-fold) was upregulated. Therefore, RR water extracts upregulate many pro-survival genes while downregulating many pro-death genes. It is interpreted that these genes, in combination with other regulated genes, can promote neuronal survival in a stress such as hypoxia.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.442-451
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• 2016

The aim of this study was to investigate the anti-inflammatory effect of Sargassum miyabei Yendo ethanol extract (SMYEE) using RAW 264.7 cells and croton oil-induced Balb/c mice. SMYEE inhibited the production of pro-inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor $(TNF)-{\alpha}$, and $IL-1{\beta}$] and nitric oxide in lipopolysaccharide (LPS)-induced inflammatory response. In addition, SMYEE suppressed the expression of inducible nitric oxide, cyclooxygenase-2, and nuclear factor-kappa B. Further, SMYEE inhibited the expression of mitogen-activated protein kinases (MAPKs), such as extra cellular signal-regulated kinase 1/2, p38, and c-Jun N-terminal kinase. In ear edema test, edema formation in the SMYEE treatment was lower than that in the positive control and was similar to that in the prednisolone treatment group. Photomicrographs of mice ear tissue showed a reduction in dermal thickness and number of infiltrated mast cells. Therefore, our results indicate that SMYEE exerts an anti-inflammatory effect via inhibition of nuclear factor ${NF}-{\kappa}B$ and MAPK activation and can be used as a natural source of anti-inflammatory compounds.

• Childhood Kidney Diseases
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• v.7 no.1
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• pp.9-15
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• 2003

Purpose : Several studies have suggested that hyperlipidemia might be a causative factor contributing to the progression of initial glomerular injury through the development of glomerulosclerosis. We examined the potential beneficial effect of atorvastatin - which blocks the rate limiting step of cholesterol synthesis by inhibiting HMG-CoA reductase - in PAN-induced nephrosis. Materials and Methods : Glomerulosclerosis was induced in Sprague-Dawley male rats by repeated administration of PAN. Sprague-Dawley male rats were divided into 3 groups : group I(control), group II(PAN 20 mg/kg, subcutaneous injection), group III(PAN 20 mg/kg subcutaneous injection and atorvastatin 50 mg/kg/day per oral). On the 11th week, upon sacrifice of the experimental animals, blood sampling, 24-hr urine collection and nephrectomy were performed. Results : Group III had significantly lower BUN and higher serum albumin($30.9{\pm}17.2\;vs.\;17.3{\pm}2.5\;mg/dL;\;2.3{\pm}0.1\;vs.\;2.5{\pm}0.2\;g/dL$, P<0.05) compared with group II. In the lipid profiles, group III was associated with a reduction in total cholesterol and LDL($291{\pm}173\;vs.\;167{\pm}72\;mg/dL:\;57{\pm}53\;vs.\;27{\pm}12\;mg/dL$, P>0.05) compared with group II. Atorvastatin administration lowered the glomerular sclerosing index significantly(26.2% vs. 13.3%, P<0.05). Conclusion : Puromycin-induced glomerulosclerosis could be ameliorated by the reduction of hyperlipidemia with atorvastatin. This suggests that hyperlipidemia contributes to the pathogenesis of glomerulosclerosis.

• Korean Journal of Optics and Photonics
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• v.22 no.4
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• pp.184-190
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• 2011

A compact imaging spectrometer (COMIS) was developed for a microsatellite STSAT-3. The satellite is now rescheduled to be launched into a low sun-synchronous Earth orbit (~700 km) by the end of 2012. Its main operational goal is the imaging of the Earth's surface and atmosphere with ground sampling distance of 27 m and 2 - 15 nm spectral resolution over visible and near infrared spectrum (0.4 - 1.05 ${\mu}m$). A flight model of COMIS was developed following an engineering model that had successfully demonstrated hyperspectral imaging capability and structural rigidity. In this paper we report the environmental test results of the flight model. The mechanical stiffness of the model was confirmed by a small shift of the natural frequency i.e., < 1% over 10 gRMS random vibration test. Electrical functions of the model were also tested without showing any anomalies during and after vacuum thermal cycling test with < $10^{-5}$ torr and $-30^{\circ}C\;-\;35^{\circ}C$. The imaging capability of the model, represented by a modulation transfer function (MTF) value at the Nyquist frequency, was also kept unvaried after all those environmental tests.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.2
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• pp.119-133
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• 2022

Due to the improvement of surveying, mapping and communication techniques, various apps for road direction guides and vehicle navigations have been developed. Although such a development has impacted on walking and driving, there is a limit to improving the daily convenience of the socially impaired people. This is mainly due to the fact that the software have been developed for normal pedestrians and drivers. Therefore, visually impaired people still have problems with the confusion of direction and/or non-provision of risk factors in walking. This study aimed to propose a scheme which constructs data for mobility-impaired or traffic-impaired people based on various geospatial information. The factors and components related to walking for the visually impaired are selected by geospatial data and a walking route guidance network that can be applied to a commercial software. As a result, it was confirmed that road direction guidance would be possible if additional contents, such as braille blocks (dotted/linear), sound signals, bus stops, and bollards are secured. In addition, an initial version of the application software was implemented based on the suggested data model and its usefulness was evaluated to a visually impaired person. To advance the stability of the service in walking for the visually impaired people, various geospatial data obtained by multiple institutes are necessary to be combined, and various sensors and voice technologies are required to be connected and utilized through ICT (Information and Communications Technologies) technology in near future.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.6
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• pp.253-266
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• 2020

The extended slip-weakening model was investigated by using a compiled set of source-spectrum-related parameters, i.e. seismic moment M_o, S-wave velocity V_s, corner-frequency f_c, and source-controlled high-cut frequency fmax, for 113 shallow crustal earthquakes (focal depth less than 25 km, M_W 3.0~7.5) that occurred in Japan from 1987 to 2016. The investigation was focused on the characteristics of stress drop, radiation energy-to-seismic moment ratio, radiation efficiency, and fracture energy release rate, G_c. The scaling relationships of those source parameters were also investigated and compared with those in previous studies, which were based on generally used singular models with the dimensionless numbers corresponding to f_c given by Brune and Madariaga. The results showed that the stress drop from the singular model with Madariaga's dimensionless number was equivalent to the breakdown stress drop, as well as Brune's effective stress, rather than to static stress drop as has been usually assumed. The scale dependence of stress drop showed a different tendency in accordance with the size category of the earthquakes, which may be divided into small-moderate earthquakes and moderate-large earthquakes by comparing to M_o = 10¹⁷~10¹⁸ Nm. The scale dependence was quite similar to that shown by Kanamori and Rivera. The scale dependence was not because of a poor dynamic range of recorded signals or missing data as asserted by Ide and Beroza, but rather it was because of the scale dependent V_r-induced local similarity of spectrum as shown in a previous study by the authors. The energy release rate G_c with respect to breakdown distance D_c from the extended slip-weakening model coincided with that given by Ellsworth and Beroza in a study on the rupture nucleation phase; and the empirical relationship given by Abercrombie and Rice can represent the results from the extended slip-weakening model, the results from laboratory stick-slip experiments by Ohnaka, and the results given by Ellsworth and Beroza simultaneously. Also the energy flux into the breakdown zone was well correlated with the breakdown stress drop, ${\tilde{e}}$ and peak slip velocity of the fault faces. Consequently, the investigation results indicate the appropriateness of the extended slip-weakening model.