• Knowledge Management Research
• /
• v.25 no.1
• /
• pp.193-215
• /
• 2024

This study aims to identify the main factors that caused the digital divide during the COVID-19 pandemic. Utilizing data from the 2020 and 2021 Digital Divide Surveys by the National Information Agency, a research model was constructed for analysis using SmartPLS 4, applying PLS-SEM and Multigroup Analysis methods. The results of the study are as follows. First, combining 2020 and 2021, mobile internet usage during COVID-19 is positively associated with digital skills, digital usage, and usage outcomes except for networking. Second, the impact of digital usage was significantly higher during the outbreak than during the beginning of COVID-19, which may be due to the increased demand for digital usage as the outbreak continued, and the corresponding increase in internet usage. Third, we discovered that demographics are not the main factor affecting changes in mobile internet use during the COVID-19 pandemic. Instead, digital literacy affects mobile usage, which is the most important one. The results show the importance of creating programs to teach people how to use technology appropriately. We propose that digital literacy should be central to training programs for people who use digital services.

• Journal of Animal Science and Technology
• /
• v.54 no.2
• /
• pp.103-109
• /
• 2012

Present study was performed to investigate the effect of single and co-culture of adipocyte and muscle cell lines on cell differentiation. 3T3-L1 (adipocyte) and L6 (muscle) cell lines were single-cultured on the condition of 10% fetal bovine serum (FBS)/Dulbeco's modified eagle's medium (DMEM) for 48 h followed by culture within 5% FBS/DMEM as a growth media. Then, the growth media was replaced by differentiation media composed of 2% FBS/DMEM without additives in single- or co-culture of the 3T3-L1 and the L6 cells to induce differentiation of both cell types. In co-culture system, the 3T3-L1 and the L6 cells were grown in separated places by being seeded on a $0.4{\mu}m$ insert membrane and on the bottom of 6 well plate, respectively. Cell differentiation was measured using morphological investigation and cytosolic analysis of glycerol-3-phosphate dehydrogenase (GPDH; for 3T3-L1) and creatine kinase (CK; for L6). Based on the GPDH results, the presence of L6 cells did not stimulate 3T3-L1 differentiation showing more differentiation of 3T3-L1 cells in the single-culture compared to the co-culture condition. In contrast, 3T3-L1 cells in the co-culture promoted differentiation of L6 cells. Enzymatic analysis supported this result showing that 3T3-L1 cells showed statistically (P<0.05) higher GPDH activity in the single-culture than the co-culture, whereas CK results of L6 cells were vice versa (P<0.05). Overall, present results may indicate that co-culture system is more reliable and precise technique compared to single-culture. Further studies on several co-culture trials including different media conditions, supplementation of differentiating substances, molecular biological analysis, etc. should be required to obtain practical and fundamental mass data.

• Journal of Animal Science and Technology
• /
• v.51 no.3
• /
• pp.231-240
• /
• 2009

Sixteen ruminally cannulated Korean native steers (Hanwoo; $626.2\pm47.72$ kg) were used to investigate the effects of polyclonal antibodies against abdominal (AAb) and subcutaneous adipocyte membrane proteins (SAb) on ruminal fermentation patterns and blood metabolites. The body weight (BW) of Hanwoo was decreased 2-weeks after AAb and SAb injection, BW reduction was also observed in control and non-immunized serum groups, indicating that stress induced by other factors (e.g. blood sampling etc.) rather than antibodies injection may affect the BW reduction. Antibodies treatment did not affect (P > 0.05) rumen pH, volatile fatty acids and ammonia-N concentration. The ranges were similar with typical ranges of those in Hanwoo. Compared with control, blood urea N concentration was decreased in AAb group and increased (P < 0.05) in SAb group before antibodies treatment. However, none of the groups were significantly (P > 0.05) affected at 2- or 4-weeks after the treatment. Concentration of plasma glucose in the non-immunized serum group was significantly higher (P < 0.05) than the other groups at 0-week after treatment. However, antibodies treatment did not affect the concentration of plasma glucose. Concentration of plasma triglyceride showed no difference (P > 0.05) between the groups and ranged from 11.4 to 19.9 mg/dl, which is the perfect range of plasma triglyceride of Hanwoo fed concentrate based diets. In conclusion, these results may indicate that the present AAb and SAb have safety in nutritional physiological metabolism in Hanwoo. Further study on in vivo fat reduction of the antibodies against abdominal and subcutaneous adipocytes PMPs of Hanwoo is required for inedible fat-reduced high quality beef production.

• Clinical and Experimental Pediatrics
• /
• v.48 no.5
• /
• pp.488-494
• /
• 2005

Purpose : To outline the aspects of extubation by birth weight and find the predictors for success/failure at the first extubation in extremely low birth weight infants. Methods : One hundred thirteen extremely low birth weight infants(<1,000 g) who were admitted to NICU at Samsung Seoul Hospital between Jan. 2000 and Jun. 2004 were enrolled. Clinical characteristics that are thought to be related with extubation success or failure were compared with the success and the failure of the first extubation. Results : As the birth weight decreased, extubation success day was significantly delayed : $16{\pm}3day(d)$ in 900-999 g; $20{\pm}3d$ in 800-899 g; $35{\pm}4d$ in 700-799 g; $37{\pm}9d$ in 600-699 g; $49{\pm}12d$ in ${\leq}599g$. 25 out of 113 infants(22%) failed the first extubation. Preterm premature rupture of membrane was associated with extubation success, and air leak was associated with extubation failure, with a borderline significance. Postnatal and corrected age and body weight at the first extubation, nutritional status, and ventilator settings were not associated with extubation success or failure. Extubation success day was significantly delayed, and the incidence of late-onset sepsis and mortality was significant higher in the failure of the first extubation. Conclusion : We could not find significant predictors for success/failure at the first extubation. The failure of the first extubation had an increased risk of late-onset sepsis and death. Further studies are needed to find the predictors for extubation success/failure.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.12
• /
• pp.246-257
• /
• 2018

The purpose of this study was to investigate the effects of physical health status and social support on depression and quality of life among the elderly in G City. This is a descriptive research study of 497 elderly residents in 45 senior citizen centers in G city; the data were collected from March 5 to 30, 2018. Data were analyzed using the IBM SPSS/win 24.0 program by t-test, ANOVA and multiple regression analysis. In physical health status, the chronic disease score was $1.35{\pm}0.91$, the functional status score was $1.80{\pm}4.45$, and the subjective health score was $3.14{\pm}1.13$. The average score for social support in the emotional network was $5.71{\pm}1.13$. In the sub-region of the social network, the score for frequency of contact with relatives was $2.92{\pm}1.31$, that for contact with friends was $3.18{\pm}0.98$, and that for social participation was $0.68{\pm}0.82$. In the multiple regression analysis of factors affecting depression and quality of life, the explanatory power of physical health status and quality of life was 45.5% and 21.1%, respectively. The explanatory power of depression based on social support and quality of life was 46.7% and 27.5%, respectively. This study indicates that physical health status and social support affect depression and quality of life. Therefore, programs should be developed to increase the physical health status and social support and thus improve the quality of life of the elderly in the community.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.25 no.6
• /
• pp.583-603
• /
• 2023

Recently, the advancement of mechanical tunnel boring machine (TBM) technology and the characteristics of subsea railway tunnels subjected to hydrostatic pressure have led to the widespread application of shield TBM methods in the design and construction of subsea railway tunnels. Subsea railway tunnels are exposed in a constant pore water pressure and are influenced by the amplification of seismic waves during earthquake. In particular, seismic loads acting on subsea railway tunnels under various ground conditions such as soft ground, soft soil-rock composite ground, and fractured zones can cause significant changes in tunnel displacement and stress, thereby affecting tunnel safety. Additionally, the dynamic response of the ground and tunnel varies based on seismic load parameters such as frequency characteristics, seismic waveform, and peak acceleration, adding complexity to the behavior of the ground-tunnel structure system. In this study, a finite difference method is employed to model the entire ground-tunnel structure system, considering hydrostatic pressure, for the investigation of dynamic behavior of subsea railway tunnel during earthquake. Since the key factors influencing the dynamic behavior during seismic events are ground conditions and seismic waves, six analysis cases are established based on virtual ground conditions: Case-1 with weathered soil, Case-2 with hard rock, Case-3 with a composite ground of soil and hard rock in the tunnel longitudinal direction, Case-4 with the tunnel passing through a narrow fault zone, Case-5 with a composite ground of soft soil and hard rock in the tunnel longitudinal direction, and Case-6 with the tunnel passing through a wide fractured zone. As a result, horizontal displacements due to earthquakes tend to increase with an increase in ground stiffness, however, the displacements tend to be restrained due to the confining effects of the ground and the rigid shield segments. On the contrary, peak compressive stress of segment significantly increases with weaker ground stiffness and the effects of displacement restrain contribute the increase of peak compressive stress of segment.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.5 no.2
• /
• pp.39-44
• /
• 1972

Considerable damages of the cultivated Porphyra by Porphyra diseases were reported from the Porphyra culture bed along the coast of Yongwon-ri, Changwon, Kyungnam during the years of 1969 and 1970. The present study deals with the effects of fertilizer plant effluents on the Porphyra diseases, and the results are summarized as follows : 1. By the result of current observation, the polluted water of Haeng-am Bay which has an inflow of pollutants from the fertilizer plant was affecting the bed with tides. The results of pollution studies in Chinhae Bay and adjacent waters conducted by Won and Park(1971) also show that Chinhae Bay and adjacent waters are contaminated with the plant effluents. It seems that the effect increases due to the wind drift current when north-westerly or westerly winds prevail. Accordingly, effects of the Porphyra diseases in the culture bed seem to originate from the pollutants, since there are more damages when the north-westerly or westerly winds prevail, and also spring tide develops. 2. As compared to the photosynthetic activity of the Porphyra suborbiculata in uncontaminated seawater, it decreases up to $4\%$ in 200pmm, $20\%$ in 300ppm and $43\%$ in 1,000ppm of contaminated seawater which contains dilluted pollutants from the fertilizer plant. The results of the measurements using the water collected in the polluted area of Chinhae Bay and adjacent waters revealed that the photosynthesis was depressed about 21 to $34\%$ near the plant, and in the area of the Porphyra beds, $15\%$ in the portion where tide is weak and $5\%$ where the tide is strong, in comparison with the area of unpolluted water. 3. Although the present results do not indicate the exact level of harmful pollutants, it is evident that the pollutants of the plant effluents interfere photosynthetic activity of the Porphyra, even in the water containing pollutants as low as 200 ppm.

• Korean Journal of Organic Agriculture
• /
• v.25 no.4
• /
• pp.773-788
• /
• 2017

This study was carried out to investigate the damage patterns, the occurrence and migration time of Pseudococcus comstocki and in order to improve the control effect of organic agricultural materials (OAMs). The experiment was carried out at Okcheon's organic vineyard ($2,500m^2$, sandy loam, manure) where planted 8~9 year old 'Muscat of Alexandria' vines. The comstock mealybug's migration to grape clusters occurred from the middle of July, and produced eggs in the grape clusters from the end of July, and the density of the comstock mealybug was highest at $0.6cm^2$ in late August. The number and fruit damage of comstock mealybug in eco-friendly vineyards were higher than in conventional culture vineyard. And the marketability of green variety grape was more damaged from comstock mealybug than the black variety grape. Toxicities of 8 OAMs were evaluated to comstock mealybug at the recommended concentration. As a results, Lightyellow sophora and Derris extracts exhibited strong insecticidal activity with 100% mortality. When the Lightyellow sophora extract was uniformly distributed on the vine from early-July to mid-July, fruit damage reduction rate was 96.2% and 84.6%, respectively. So commercial grapes could be harvested. Therefore, it was considered to be effective to reduce fruit damage by controlling in early - late July (the green stage) when the comstock mealybug migrated to grape clusters in the vine greenhouse. In the future, it will be necessary to study the effect of external exposure time and momentum on the control of OAMs.

• Journal of Animal Science and Technology
• /
• v.52 no.5
• /
• pp.375-382
• /
• 2010

Twelve pigs were used to investigate the effects of polyclonal antibody candidate against abdominal (AAb) and subcutaneous adipocyte membrane proteins (SAb) on body weight, fecaldigestibility and blood metabolites. When AAb and SAb developed by Choi et al. (2010) were injected to pigs, the numerical increase in BW (body weight) occurred at 4 weeks post-treatment, but BW for an entire period was also increased, indicating that the BW increase may not be affected by the antibodies injection. Antibodies treatment did not affect (P>0.05) fecal digestibility of dry matter, crude protein, crude fat and crude fiber. Fecal digestibility of crude ash for control (no treatment) at 2 weeks decreased, and that for non-immunized serum treatmentgroup at 4 weeks post-treatment increased, respectively (P<0.05). However, fecal digestibility of crude ash for AAb and SAb groups did not significantly change. At 4 weeks after the antibodies treatment, blood urea N concentration for AAb and SAb groups was significantly increased (P<0.05). However, these increases may not be caused by the antibodies treatment because similar pattern in blood urea N concentration occurred before the antibodies treatment. Antibodies treatment did not affect concentration of plasma glucose and triglycerides (P<0.05). Compared with control, concentration of plasma total cholesterol for AAb and SAb groups at 4 weeks post-treatment was significantly (P<0.05) decreased. This may suggest that body fat reduction possibly occurs. In conclusion, the AAb and the SAb developed by Choi et al. (2010) may have safety in nutritional physiological metabolism in pigs. Further study on in vivo fat reduction of the antibodies against abdominal and subcutaneous adipocytes of pigs should be required for fat-reduced pork production.

• Journal of radiological science and technology
• /
• v.39 no.4
• /
• pp.651-660
• /
• 2016

Due to recent population aging, the number of check-up for senior citizens has increased steadily. According to this trend, the market size of dental X-ray equipment and the number of approval and review for these devices have simultaneously increased. The technical document of medical device is required for approval and review for medical device, and medical device companies needs to have work comprehension and expertise, as the document needs to include the overall contents such as performances, test criteria, etc.. Yet, since most of domestic manufacturers or importers of medical devices are small businesses, it is difficult for them to recruit professional manpower for approval of medical devices, and submission of inaccurate technical documents has increased. These problems lead to delay of the approval process and to difficulties in quick entering into the market. Especially, the Ministry of Food and Drug safety (MFDS) standards of a dental extra-oral X-ray equipment, a dental intra-oral X-ray equipment, an arm-type computed tomography, and a portable X-ray system have been recently enacted or not. this guideline of dental X-ray equipment adjusting revised standards was developed to help relative companies and reviewers. For this study, first, the methods to write technical document have been reviewed with revised international and domestic regulations and system. Second, the domestic and foreign market status of each item has been surveyed and analyzed. Third, the contents of technical documents already approved by MFDS have been analyzed to select the correct example, test items, criteria, and methods. Finally, the guideline has been developed based on international and domestic regulation, through close review of a consultative body composed of academic, industrial, research institute and government experts.