• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.362-371
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• 2004

It is essential to have adequate knowledge of the timing of root resorption of deciduous teeth for diagnosis and treatment planning in pediatric and orthodontic dentistry. Dental development is also influenced by hereditary characteristics, environmental factors, race, sex, endocrine reaction, nutrition, socioeconomic condition and secular factor. The aims of the present study were to determine the mean age of root resorption of deciduous teeth in contemporary Korean children and to compare the mean age of root resorption time of deciduous teeth between early 1990s and early 2000s. The study population was made up of Korean children attending the pediatric dentistry ward of Kyungpook National University Hospital. One thousand thirty seven children's panoramic radiograph (girls: 528 persons, boys: 509 persons) in $1990{\sim}1992$ and one thousand sixty five children's panoramic radiograph (girls: 394 persons, boys: 671 persons) in $2001{\sim}2003$ were examined. This study utilized a cross-sectional design. Due to the problems of imaging in the maxillary region and the mandibular incisor region, the mandibular deciduous canine, the mandibular deciduous first molar and the mandibular deciduous second molar were chosen for examination. The results were as follows. 1. There is a tendency for the teeth to resort earlier in the early 2000s group than the in early 1990s group. At the Res c stage, the difference of the mean age was 0.4 years. 2. At the Res c stage, the order of difference of the mean age from smaller to larger for the girls was the mandibular deciduous canine, the mandibular first deciduous molar, and the mandibular second deciduous molar. On the other hand, for the boys, the order was the mandibular second deciduous molar, the mandibular first deciduous molar, and the mandibular deciduous canine. The difference was larger with aging in girls and smaller with aging in boys. 3. There is a tendency for the teeth to resort earlier in girls in both the early 1990s group and the early 2000s group. The difference of the mean age between girls and boys was 0.3 year. 4. The commencement of root resorption of the mandibular deciduous canine was slower than that of the mandibular first deciduous molar. However, the completion of root resorption of the mandibular deciduous canine is faster than that of the mandibular first deciduous molar. The total elapsed time of root resorption from commencement to completion was shortest in the mandibular deciduous canine. 5. For each of the teeth in the early 1990s and the early 2000s groups, the speed of root resorption was in the later stage faster than in the earlier stage. In order to know about the exact timing of root resorption of deciduous teeth, periodic and longitudinal studies preferably covering the entire period of growth, is required.

• Clinical and Experimental Pediatrics
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• v.51 no.5
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• pp.518-522
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• 2008

Purpose : The purpose of this study was to investigate the prevalence of enuresis in association with voiding habits and socioeconomic status in elementary school children. Methods : A dynamic survey was done of 1,514 students from two elementary schools in Suwon, Korea in December 2006. Data regarding gender, age, height and weight, voiding habits, and monthly family incomes were gathered and analyzed to discover any correlation with the incidence of enuresis. The percentile value of height or weight was extrapolated from the standard population curve. Results : Among 1,514 children, 1,063 (70.2%) answered and returned the questionnaires. Overall, the prevalence of enuresis was 8.7% and there was no difference between the public (8.8%) and private school (8.7%). The family incomes of the students from the two schools differed greatly from each other, but there was no difference in the prevalence of enuresis between the two schools. Children with a habit of void-holding showed a higher prevalence of enuresis. No significant correlation was found between the prevalence of enuresis and the height and weight percentile of children. Experience with hospital visits was low among enuretic children (20.8%), suggesting that Korean parents tend to neglect treatment of enuresis for their children. The prevalence of enuresis decreased by 2.0% each year, as school children aged. Conclusion : The overall prevalence of enuresis among elementary school children in Suwon district was 8.7%. The 12.1% prevalence of enuresis at the seven years came down gradually, to be nil at the age of 13. Infrequent urination or void-holding was assumed to be one of the important factors causing enuresis in elementary school children.

• Asia pacific journal of information systems
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• v.17 no.2
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• pp.123-137
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• 2007

The advent of the Internet and related Web technologies has created an easily accessible link between a firm and its customers, and has provided opportunities to a firm to use information technology to support supplementary after-sale services associated with a product or service. It has been widely recognized that supplementary services are an important source of customer value and of competitive advantage as the characteristics of the product itself. Many of these supplementary services are information-based and need not be co-located with the product, so more and more companies are delivering these services electronically. Net-based customer service, which is defined as an Internet-based computerized information system that delivers services to a customer, therefore, is the core infrastructure for supplementary service provision. The importance of net-based customer service in delivering supplementary after-sale services associated with product has been well documented. The strategic advantages of well-implemented net-based customer service are enhanced customer loyalty and higher lock-in of customers, and a resulting reduction in competition and the consequent increase in profits. However, not all customers utilize such net-based customer service. The digital divide is the phenomenon in our society that captures the observation that not all customers have equal access to computers. Socioeconomic factors such as race, gender, and education level are strongly related to Internet accessibility and ability to use. This is due to the differences in the ability to bear the cost of a computer, and the differences in self-efficacy in the use of a technology, among other reasons. This concept, applied to e-commerce, has been called the "e-commerce divide." High Internet penetration is not eradicating the digital divide and e-commerce divide as one would hope. Besides, to accommodate personalized support, a customer must often provide personal information to the firm. This personal information includes not only name and address, but also preferences information and perhaps valuation information. However, many recent studies show that consumers may not be willing to share information about themselves due to concerns about privacy online. Due to the e-commerce divide, and due to privacy and security concerns of the customer for sharing personal information with firms, limited numbers of customers adopt net-based customer service. The limited level of customer adoption of net-based customer service affects the firm profits and the customers' welfare. We use a game-theoretic model in which we model the net-based customer service system as a mechanism to enhance customers' loyalty. We model a market entry scenario where a firm (the incumbent) uses the net-based customer service system in inducing loyalty in its customer base. The firm sells one product through the traditional retailing channels and at a price set for these channels. Another firm (the entrant) enters the market, and having observed the price of the incumbent firm (and after deducing the loyalty levels in the customer base), chooses its price. The profits of the firms and the surplus of the two customers segments (the segment that utilizes net-based customer service and the segment that does not) are analyzed in the Stackelberg leader-follower model of competition between the firms. We find that an increase in adoption of net-based customer service by the customer base is not always desirable for firms. With low effectiveness in enhancing customer loyalty, firms prefer a high level of customer adoption of net-based customer service, because an increase in adoption rate decreases competition and increases profits. A firm in an industry where net-based customer service is highly effective loyalty mechanism, on the other hand, prefers a low level of adoption by customers.

• Journal of the Korean association of regional geographers
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• v.23 no.1
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• pp.151-167
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• 2017

The main objective of this study was to investigate the climatic impact of $PM_{10}$ concentration on the temperature change pattern in Busan Metropolitan City(BMC), Korea during 2001~2015. Mean $PM_{10}$ concentration of BMC has gradually declined over the past 15 years. While the highest $PM_{10}$ concentration was observed in spring followed by winter, summer, and fall on average, the seasonal variations of $PM_{10}$ concentration differed from place to place within the city. Frequency analysis showed that the most frequently observed $PM_{10}$ concentration ranged from $20{\mu}g/m^3$ to $60{\mu}g/m^3$, which accounted for 64.6% of all daily observations. Overall, the west-high and east-low pattern of $PM_{10}$ concentration was relatively strong during the winter when the effect of yellow-dust events on the air quality was weak. Comparative analyses between $PM_{10}$ concentration and monthly temperature slope derived from generalized temperature curves indicated that the decreasing trend of $PM_{10}$ concentration was associated with increases of annual temperature range, and $PM_{10}$ concentration had a negative relationship with the temperature slope of warming months. Overall, $PM_{10}$ concentration had a weak correlation with the annual mean temperature, but it had a significant, positive correlation with the winter season, which had a dominant influence on the annual mean temperature. In terms of energy budget, it has been known that the change in $PM_{10}$ concentration contributes to the warming or cooling effect by affecting the radiative forcing due to the reflection and absorption of radiant energy. The correlation between $PM_{10}$ concentration and temperature changes in the study area was not seasonally and spatially consistent, and its significance was statistically limited partly due to the number of observations and the lack of potential socioeconomic factors relevant to urban air quality.

• Journal of agricultural medicine and community health
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• v.34 no.2
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• pp.175-187
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• 2009

Objectives: This study was conducted to investigate whether joint effects between family allergy history and environmental tobacco smoke(ETS) by parents were associated with pediatric asthma and wheezing. Methods: The study objects of this study were 2301 element school students and their parents in an urban-rural areas of Gyeonggi-do. Pediatric asthma and wheezing were identified by measures of International Study of Asthma and Allergies in Childhood (ISAAC) questionnaires. We investigated history of parental allergy, ETS, and other socioeconomic status of both parent. Data were analyzed using logistic regression methods. Results: After adjusting other variables, children with maternal asthma history were more likely to be reported life time wheezing (OR: 3.79 95%CI:2.43-5.90), recent wheezing (OR:4.09 95%CI:2.28-7.38), and diagnostic asthma (OR:2.61 95%CI: 1.44-4.75). Paternal asthma history increasing risk of life time wheezing (OR 2.01 95%CI:1.19-3.38) and recent wheezing (OR:2.38 95%CI:1.24-4.56). Joint effect between parental allergy history and ETS significantly effected on child's life time wheezing and recent wheezing. The risks of life time wheezing (OR:2.47 95%CI:1.64-3.717) and recent wheezing (OR: 2.51 95%CI:1.34-4.69) were significantly higher than others without both factors. The risk of recent wheezing of children with maternal recent smoking and parental allergy history (OR:4.83 95%CI:1.89-12.33) was higher than their counterpart. Conclusions: The result of this study implies that children with family allergy history and passive smoking are more likely to be get asthma and wheezing than children with family allergy history and non-passive smoking. This study provide the object information to increase the efficiency of non-smoking campaign and education for decreasing pediatric asthma risk.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.400-412
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• 2023

In this study, the biogeochemistry management (BGC-MAN) model was applied to North and South Korea pine and oak forest stands to evaluate the Net Primary Productivity (NPP), an indicator of forest ecosystem productivity. For meteorological information, historical records and East Asian climate scenario data of Shared Socioeconomic Pathways (SSPs) were used. For vegetation information, pine (Pinus densiflora) and oak(Quercus spp.) forest stands were selected at the Gwangneung and Seolmacheon in South Korea and Sariwon, Sohung, Haeju, Jongju, and Wonsan, which are known to have tree nurseries in North Korea. Among the biophysical information, we used the elevation model for topographic data such as longitude, altitude, and slope direction, and the global soil database for soil data. For management factors, we considered the destruction of forests in North and South Korea due to the Korean War in 1950 and the subsequent reforestation process. The overall mean value of simulated NPP from 1991 to 2100 was 5.17 Mg C ha^-1, with a range of 3.30-8.19 Mg C ha^-1. In addition, increased variability in climate scenarios resulted in variations in forest productivity, with a notable decline in the growth of pine forests. The applicability of the BGC-MAN model to the Korean Peninsula was examined at a time when the ecosystem process-based models were becoming increasingly important due to climate change. In this study, the data on the effects of climate change disturbances on forest ecosystems that was analyzed was limited; therefore, future modeling methods should be improved to simulate more precise ecosystem changes across the Korean Peninsula through process-based models.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.230-238
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• 1998

Purpose : Worldwidely, the incidence of the hepatitis A has been markedly decreased in the past years. Also in Korea, there has been only a few sporadic cases without evidence of epidemics since the mid 1980s. However, the incidence of the hepatitis A in young adults and childen has been in trends of increasing since 1996. So, we retrospectively performed the study on the epidemiolgical changes and the clinical feature of hepatitis A in childen, living in Kyung-gi province, since 1988 to 1998. Methods : The four affiliated hospitals of the Catholic University of Korea, Our lady of Mercy's hospital, Holy family hospital, Eui-Jung-bu St. Mary's hospital, and St. Vincent hospital, were enrolled in this study. We conducted statistical analysis on the incidence of hepatitis A since 1988 to 1998, concerning with the period (monthly, annually), age, sex and related epidemiological property, by reviewing the hospital records of the patients with hepatitis A. We simultaneously performed the study concerning with the clinical characteristics of hepatitis A. Results : 1) During the study period, 46 children was diagnosed as hepatitis A, and among them 28 children (60.1%) developed sporadically in the 1998. And sex ratio was 1.2(male):1(female). 2) Most of the patients developed between March and July, and hepatitits A were mainly developed in the patients above the 10 year old ages(37 patients; 80.4%). 3) The socioeconomic and educational status of the patient's parents was almostly below the middle and low class. Although, we could not find the etiological factors in most cases, but we found the evidence of interfamilial transmission in one family. 4) The patients complained the symptoms of nausea and vomiting, jaundice, poor appetite, mild fever, fatigueness, abdominal pain, URI symptom, dyspepsia, dark urine, headache and diarrhea in order, and findings of jaundice, hepatomegaly, RUQ tenderness, splenomegaly and LLQ tenderness in order were seen. 5) All patients showed abnormal findings of the liver function tests, and the pattern of cholestatic hepatitis were seen in most cases, but these findings were normalized within the 2~4 weeks. The findings of the gall bladder wall thickening, hepatomegaly, splenomegaly and ascites were seen on abodominal sonogram. 6) The prognosis of all patients were good without complications, except in one case who had the episode of transient recuurence. And the mean hospitalization dates were 11.1 days. Conclusion : We found that the incidence of hepatitis A showed the increasing trend, and peaked in the 1998 in Kyung-gi province children. And hepatitis A mainly developed in children above the 10 year old ages. The scioeconomic and educational status of patient's family was almostly below the middle class. All of them showed abnormal liver function, and clinically cholestatic hepatitis features were seen in most cases. But, the prognosis was excellent without complication in all cases.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.4
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• pp.101-118
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• 2023

During the COVID-19 pandemic, the utilization rate of neighborhood parks and green spaces increased significantly, and the outbreak served as an opportunity to highlight the values and functions of neighborhood parks and green spaces for urban residents. This study aims to empirically analyze how citizens' movement and the use of neighborhood parks and green spaces changed before and after COVID-19 and examine the social and spatial characteristics that affected these changes. As a research method, first, people's mobility around neighborhood parks and green spaces before and after the COVID-19 pandemic were compared using signal data from telecommunication carriers. Through the analysis of changes in residence time and movement volume, the movement characteristics of citizens after COVID-19 and changes in walking-based park visits were examined. Second, the factors affecting the mobility change in neighborhood parks and green spaces were analyzed. The social and spatial characteristics that affect citizens' visits to neighborhood parks and green spaces before and after COVID-19 were examined through correlation and multiple regression analysis. Subsequently, through cluster analysis, the types of living areas for the post-COVID era were classified from the perspective of the supply and management of neighborhood parks and green spaces services, and directions for improving neighborhood parks and green spaces by type were presented. Major research findings are as follows: First, since the outbreak of COVID-19, activities within 500m of the residence have increased. The amount of stay and walking movement increased in both 2020 and 2021, which means that the need to review the quantitative standards and attractions of neighborhood parks and green spaces has increased considering the changed scope of the walking and living area. Second, the overall number of visits to neighborhood parks and green spaces by walking has increased since the outbreak of COVID-19. The number of visits to neighborhood parks and green spaces centered on the house and the workplace increased significantly. The park green policy in the post-COVID era should be promoted by discovering underprivileged areas, focusing on areas where residential, commercial, and business facilities are concentrated, and improving neighborhood parks and green services in quantitative and qualitative terms. Third, it was found that the higher the level of park green service, the higher the amount of walking movement. It is necessary to use indicators that contribute to improving citizens' actual park green services, such as walking accessibility, rather than looking at the criteria for securing green areas. Fourth, as a result of cluster analysis, five types of neighborhood parks and green spaces were derived in response to the post-COVID era. This suggests that it is necessary to consider the socioeconomic status and characteristics of living areas and the level of park green services required in future park green policies. This study has academic and policy significance in that it has laid the basis for establishing neighborhood parks and green spaces policy in response to the post-COVID era by using various analysis methodologies such as carrier signal data analysis, GIS analysis, and statistical analysis.