• Journal of Communications and Networks
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• v.18 no.6
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• pp.975-988
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• 2016

Large access providers (ISPs) are seeking for new types of business agreements and pricing models to manage network costs and monetize better the provision of last-mile services. A typical paradigm of such new pricing norms is the proliferation of paid peering deals between ISPs and content providers (CPs), while on top of this, some ISPs are already experimenting with usage-based tariffs, usually through data-plans, instead of the typical fixed-based charging. In this work we define as common platform, the infrastructure in which a single ISP transacts with several CPs through peering agreements. In this context, we examine whether, and under which market conditions, the profitability of the involved stakeholders improves when the establishment of this platform is accompanied by a monetary compensation from the CPs to the ISP (paid peering), v.s. a scenario where their deal is a typical settlement-free one. In both cases, we assume that the ISP implements a usage-based access pricing scheme, implying that end-users will pay more for higher transaction rates with the CPs. Our framework captures some of the most important details of the current market, such as the various business models adopted by the CPs, the end-users' evaluation towards the ISP's and CPs' level of investments and the traffic rates per transaction for the offered services. By analysing the equilibrium derived by a leader-follower game, it turns out (among other practical takeaways) that whether or not the profitability of a CP improves, it highly depends on whether its business model is to sell content, or if it obtains its revenue from advertisements. Finally, we extract that consumer surplus is considerably higher under paid peering, which in turn implies improved levels of social welfare.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.49-55
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• 2020

Recently, companies are growing by introducing rational and optimized technology for all processes, including design. In particular, the emergence of ICT-based cloud platforms has given rise to solutions that are equipped with all the necessary business services in corporations and schools, affecting technical education and corporate growth that have not been experienced thus far. The virtual reality technology and convergence of HMD devices utilizing this platform is a new turning point in corporate development. Therefore, this study tested the VR functions used in design based on 3DEXP and HMD VR devices. Second, design utilization and this issue were examined through a survey based on the experimental data. The results showed that 3DEXP and HMD VR technologies are closely related in terms of design utilization and have demonstrated their mediated effects through statistical analysis. Nevertheless, it is not enough to generalize some engineering students as a result of the study. On the other hand, the introduction of HMD VR technology is one of the pillars of education and the implementation of virtual reality technology.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.445-454
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• 2015

The purpose of this study is to analyze the influence of the financial structure of pharmaceutical companies on R&D investment. 358 pharmaceutical firms listed in the KOSDAQ market from 2000 to 2012. Financial statements and comments in general and internal transactions were extracted from TS-2000 of the Korea Listed Company Association (KLCA), and data related to stock price was extracted from KISVALUE-III of NICE Information Service Co., Ltd. STATA 12.0 was used as the statistical package for panel analysis. The summary of the findings and the interpretation of the significance of this are as follows: First, the shareholding ratio of major shareholders and foreigners had a positive influence on R&D investment. Second, the ratio of outside directors had a negative influence on R&D investment. Third, the shareholding ratio of institutional investors did not have a significant influence on R&D investment.

• The Korean Journal of Community Living Science
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• v.14 no.3
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• pp.99-109
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• 2003

This study was conducted to collect basic marketing and management data from businesses run by farmers producing traditional Kanjang and Doenjang, fermented soybean products. The actual conditions of the fermentation processing sites at farmhouses participating in the production of soybean fermentation products were investigated. The subjects of this survey were 130 small size farmhouse Kanjang and Doenjang processing sites nationwide. The frequency, percentage, t-value, chi-square, and ANOVA were used for statistical analysis. The farmhouse business surveyed were generally operated by rural women for non-farming business income. The percentage of co-worked sites was 71.2 while the percentage of sites operating with permits was 39.2. Generally, the the facilities, size, number of working people, and output were very small. The areas in which the products were sold, site-located regions and region metropolises, were equally weighted. Sales volumes in region metropolises for sites with permits were a little higher than sites without permits. Without regard to operation type, the percentage of sales was highest in cases of direct sale by customer order. Co-worked sites have been found to have more experience in publicity than individually operated sites. As for methods of publicity, co-worked sites use mass media such as newspapers and broadcasting. Individually operated sites usually use social organizations and acquaintances. It was found that the average sales of each site totaled 25 million Won. The average income of each site was 12 million Won, and average income per participant was 3 million Won. Total sales income for sites with permits was significantly higher than sites without permits. But personal income was much higher at individually operated sites without regard to whether the site had a permit or not. This kind of business was found to contribute to an individual's time management skills as well as instill a sense of pride.

• Korean Journal of Community Nutrition
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• v.21 no.6
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• pp.558-573
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• 2016

Objectives: The purpose of this study was to evaluate the main sources of dietary sodium and potassium intake in Koreans by gender, age and regions. Methods: We used the data from 2010-2012 KNHANES. A total of 20,387 subjects aged 8 years and older were included. Intakes were compared by gender, age (8-18, 19-49 and >50 years) and geographical regions in Korea. Dishes were classified into 28 dish groups based on cooking methods. Statistical analysis was performed by using the SAS 9.3 and SUDAAN 11.0.1 software. Results: The mean sodium intake of Koreans was $4866.5{\pm}35.9mg/day$, which was 2.4 times higher than the adequate intake (AI) of sodium for Koreans. We found that daily sodium intakes were significantly different by age, gender and regions. Men and aged over 50 years had significantly higher sodium intake than women and other age groups. The mean potassium intake in Koreans was $3002.2{\pm}19.4mg/day$ and daily potassium intakes were significantly different by age, gender and regions. Women and age 50 years and over had significantly higher potassium intakes than men and other age groups. The average Na/K ratio was $2.89{\pm}0.01$ and was highest in men and in the age group of 19-49 years. The major sources of dietary sodium were soup and stew, followed by Kimchi, noodles and dumpling, pickled vegetables and seasonings, which represented 63.1 % of total sodium intakes. Soup and stew or Kimchi were the primary sources of dietary sodium intake. The major sources of dietary potassium were cooked rice, followed by soup and stew, Kimchi, fruits and beverages. Conclusions: Sodium and potassium intakes and the major sources of those were significantly different by gender, age groups and regions. Therefore, different approaches based on gender, age and regions are needed to decrease sodium intake and increase potassium intake.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.5
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• pp.467-475
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• 2007

This study compared the sea surface wind pattern between model results from KMA operational model (RDAPS) and observational results from QuikSCAT in the 2005-2006 year. The mean spatial distributions of sea surface wind show the prominent seasonal patterns of summer and winter season adjacent to Korean Peninsular. The statistical analysis also shows well seasonal variation of sea surface wind patterns between model and observation results. The BIAS value represents less than -0.5 m/s and -1 m/s in summer and winter seasons, respectively. The spatially averaged correlation coefficient shows larger than 0.7 and 0.8 in summer and winter seasons, respectively. The correlation coefficient of winter season shows higher value than that of summer season in the comparison between model and observation. This results show that the RDAPS model simulate well strong sea surface wind in winter season rather than weak sea surface wind in summer season.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.110-117
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• 2008

Three kinds of prenylated flavonols, icariside I, icariside II, and icaritin, were isolated from an icariin hydrolysate and their effects on melanogenesis evaluated based on mushroom tyrosinase inhibition and quantifying the melanin contents in melanocytes. Although none of the compounds had an effect on tyrosinase activity, icariside II and icaritin both effectively inhibited the melanin contents with an $IC_{50}$ of 10.53 and $11.13{\mu}M$, respectively. Whereas icariside II was obtained from a reaction with ${\beta}$-glucosidase and cellulase, the icariin was not completely converted into icariside II. Thus, for the high-purity production of icariside II, the reaction was optimized using the response surface methodology, where an enzyme concentration of 5.0mg/ml, pH 7, $37.5^{\circ}C$, and 8 h reaction time were selected as the central conditions for the central composite design (CCD) for the enzymatic hydrolysis of icariin into icariside II using cellulase. Empirical models were developed to describe the relationships between the operating factors and the response (icariside II yield). A statistical analysis indicated that all four factors had a significant effect (p<0.01) on the icariside II production. The coefficient of determination $(R^2)$ was good for the model (0.9853), and the optimum production conditions for icariside II was an enzyme concentration of 7.5mg/ml, pH 5, $50^{\circ}C$, and 12 h reaction time. A good agreement between the predicted and experimental data under the designed optimal conditions confirmed the usefulness of the model. A laboratory pilot scale was also successful.

• Journal of Korean society of Dental Hygiene
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• v.8 no.3
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• pp.23-36
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• 2008

This study lays its purpose on providing basic material for managing dental hygiene care programs by grasping images of the elderly perceived by dental hygienists and their behaviors toward the elderly, who have an important role in improving the elderly's dental health in the aging society. For these purposes, the researcher conducted a self-administrative questionnaire survey of 370 dental hygienists working in dental clinics or offices located in the Seoul and Daejeon areas from June 2 to 21 in 2008 and collected data, statistical analysis of the $x^2$-test, t-test, one-way ANOVA, Pearson Correlation used. resulting in the following findings. 1. In perceived images of the elderly according to their general characteristics, a subject group with under 8-year career showed 85.38 points, indicating the statistically significant difference (p=0.001). 2. When we look at perceived images of the elderly and behaviors toward them according their characteristics, in images of the elderly, a subject group with positive perceptions of the elderly showed 85.51 points (p=0.000), a subject group with meaningful old person(s), 84.66 points (p=0.000), a subject group living with old person(s), 86.04 points (p=0.001), and a subject group with experience in volunteer service activities, 84.11 points (p=0.001), and in behaviors toward the elderly, a subject group with positive perceptions of the elderly and with meaningful old person(s) showed 56.46 (p=0.036) and 55.91 points respectively, indicating the statistically significant difference (p=0.040). 3. Images of the elderly and behaviors toward them showed a positive correlation, indicating that the more positive images of the elderly, the more positive behaviors toward them (r=0.317). Putting these results together, it is thought that it is time to need continuous education and efforts regarding the formation of desirable relationships with and images of the elderly and behaviors toward them, for dental hygienists who have an important role in managing and enhancing the elderly's dental health in the aging society.

• Journal of Korean society of Dental Hygiene
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• v.18 no.5
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• pp.797-806
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• 2018

Objectives: The purpose of this study was to analyze Influence of stress on oral health and quality of life. Methods: The participants were 172 students from 4 universities located in DaeJeon, South Korea. A questionnaire was administered, assessing the impacts of the general characteristics of the participants, temporomandibular joint (TMJ) symptoms, xerostomia, and halitosis on stress. And oral impacts on daily performance were also investigated. Data were analyzed using the Statistical Package for the Social Sciences 18.0. Results: The level of stress was higher in female, and the causes of stress was reported scholastic achievement, relations with professors, get a job. The students who were higher stress were more conscious of TMJ symptoms, xerostomia and halitosis(p<0.05). Stress was significantly positively correlated with TMJ symptoms (r=0.376, p<0.001), dry mouth (r=0.360, p<0.001), and bad breath (r=0.343, p<0.001). Oral Impacts on Daily Performance (OIDP) scores were significantly positively correlated with dry mouth, bad breath, TMJ symptoms, and stress. Regression analysis showed that 54.5% of the independent variables were related to OIDP scores. Stress and TMJ symptoms exerted a significant effect on OIDP scores. Conclusions: Stress among university students affects oral health and quality of life. Stress coping mechanisms and oral health care education programs should be developed and applied at universities.

• Journal of Korean society of Dental Hygiene
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• v.20 no.5
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• pp.635-643
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• 2020

Objectives: The purpose of this study was to evaluate dental hygienists understanding of the provisions of oral health care and awareness for the elderly. Methods: A survey was conducted among 285 dental hygienists, currently practicing around Gwangju province, Korea. The questionnaire contained questions on general characteristics of the subjects (5 items), oral health status of the elderly (5 items), and awareness (8 items) among the dental hygienists. The data were analyzed using a chi-square test. IBM SPSS 21.0 program was used for all statistical analyses. Results: The results showed that 47.7% of the dental hygienists took care of 1 to 5 elderly patients per day; they could not provide high quality oral health education to these patients because of lack of knowledge, lack of treatment time, and excessive workload. An analysis of the hygienists' professional educational experience related to oral healthcare of the elderly during university years showed that the older and more experienced hygienists' were less likely to have completed this education, i.e., 22.05% and 10.9%, respectively (p<0.001). Of all the dental hygienists, 62.8% were interested in oral health problems of the elderly, and 34.4% of dental hygienists for geriatric oral care were the most needed for geriatric oral care education (p<0.001). Conclusions: According to these results, it is important that dental hygienists participate in training on oral healthcare for the elderly and develop various programs for managing the oral health of the elderly.