• Korea journal of population studies
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• v.34 no.3
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• pp.55-84
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• 2011

This study initiated with the intention to reveal the social consultations and fissures through a comparative analysis on generational characteristics by indicating occupation-related identities with the concept of social identity supported by theoretical resources. According to the three dimensions of social identity which are evaluation, potency and activity, there was more generational agreement rather than difference toward occupation-related identities. Among the 44 identities, only evaluation dimensions on minister, congressman, plane captain, farmer and potency dimensions on CEO of a major companies, professor, medical doctor, nurse, celebrity, shaman, unemployed person were statistically significant. For 'Leader and Professional', the respondents in their 50's gave high scores in both evaluation and potency dimensions. On the other side, the 30's had negative viewpoints while the 20's and 40's had neutral perspectives. For the potency dimension, the age groups were divided into the 20's, 30's and 40's, 50's; having the younger generations underestimate the potency dimension of such categories. Also for the 'General Occupation', 20's and the 30's relatively devaluated with more distinctive degree toward evaluation dimensions. For religion, 20's and 30's were positive toward buddhist monks while the 40's and 50's were more favorable with priests. For the non-economically active population, the lifetime cycle influenced each generations. When performing a two dimensional analysis toward the 'Leader and Professional' with evaluation and potency on each axis, the 50's highly evaluated both evaluation and potency dimension of such identities. However, for the 40's, 30's and 20's, the average value fell while the focus of the distribution deepened. The 30's had negative perspective toward the evaluation dimension while the 20's reflected critical attitude toward the potency dimension.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.169-177
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• 2009

In the past decade there has been increasing concern about the atopic dermatitis (AD) associated with environmental diseases. AD has been increased in the last decade and known as one of the multifactoral diseases, which has the genetic background and environmental factors at the same time. The purposes of this study were to investigate the prevalence rate and etiologic risk factors of atopic dermatitis in preschool children in Changwon, which is a one of the Korean cities and has a large industrial complex. We reviewed and analyzed the statistical data, obtained from Korea National Health Insurance Corporation, related to prevalence rate by age and administrative district. A cross-sectional questionnaire survey, based on ISAAC (International Study of Allergy and Asthma in Childhood), was conducted on random samples of preschool children (5 to 8 years old) of large sized kindergartens in Changwon. The lifetime and last one years prevalence of AD in preschool children in Changwon was increased from 1998 to 2008. The prevalence rate of AD in the preschool children in Changwon city was 9.6%. The prevalence rate in boys was 9.7% and that in girls was 9.4%. The one year prevalence of AD was ranked as middle among other provincial cities in Korea in 2008. This study showed that the prevalence rate of the atopic disease in Changwon was 9% in 2008, which was increased especially compare to 2000. More active governmental approaches for control and prevention of atopic dermatitis for children are recommended. Further studies are needed for more accurate estimation of the prevalence of AD in Korea including different regional and age population.

• Journal of health informatics and statistics
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• v.43 no.4
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• pp.344-351
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• 2018

Objectives: The purpose of this study is to investigate the impact of health behaviors of male workers without diabetes such as smoking, drinking and physical activities on HbA1c using 2015 and 2016 data from Korea National Health and Nutrition Examination Survey (KNHANES). Methods: The final study subjects of KNHANES were a total of 1,703 male workers in their 30s-50s who had normal levels of fasting blood sugar level, HbA1c, and hemoglobin. For the study variables, age, household income, educational level and occupation were included as socio-demographic characteristics; smoking behavior, drinking behavior, and physical activity behavior as characteristics of health behavior; and waist circumference, body mass index, systolic and diastolic blood pressures, total cholesterol, triglyceride and HDL cholesterol as medical examination characteristics were included. The analysis was conducted using independent variables t-test, one-way ANOVA, Pearson's correlation analysis and multiple regression analysis. Results: Socio-demographic factors that affect HbA1c were age, educational level, and occupation. As for HbA1c according to the status of current smoking, it was higher in order of the present, past and nonsmoking and HbA1c according to smoking amount pack-year increased linearly in between less than 1 pack-year and over 30 pack-year (p<0.001). Muscular exercises affected the reduction of HbA1c (p<0.05). In the multiple regression analysis with independent variables of the socio-demographic characteristics and health behavior, factors affecting HbA1c were age, occupation and smoking amount pack-year (p<0.05). In the multiple regression analysis where the characteristics of physical examination were added, factors affecting HbA1c were age, occupation, smoking amount pack-year, waist circumference and total cholesterol (p<0.001). Conclusions: As a result, the health behavior that had the most effect on HbA1c management for male workers without diabetes was the total lifetime smoking amount. Therefore, it is essential to prevent smoking as well as control, cholesterol to prevent diabetes for male workers.

• Journal of Life Science
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• v.28 no.12
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• pp.1397-1405
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• 2018

Mitochondria have multiple functions in cells: providing chemical energy, storing cellular $Ca^{2+}$, generating reactive oxygen species, and regulating apoptosis. Through these functions, mitochondria are also involved in the maintenance, proliferation, and differentiation of stem/progenitor cells. In the brain, the subventricular zone (SVZ) is one of the neurogenic regions that contains neural stem cells (NSCs) throughout a lifetime. However, reports on the role of mitochondria in SVZ NSCs are scarce. Here, we show that rotenone, a complex I inhibitor of mitochondria, inhibits the proliferation and differentiation of SVZ NSCs in different ways. In proliferating NSCs, rotenone decreases mitosis as measured through phosphorylated histone H3 detection; moreover, apoptosis is not induced by rotenone at 50 nM. In differentiating NSCs, rotenone blocks neurogenesis and oligodendrogenesis while glial fibrillary acidic protein-positive astrocytes are not affected. Interestingly, in this study there were more cells in the differentiating NSCs treated with rotenone for 4-6 days than in the vehicle control group which was a different effect from the reduced number of cells in the proliferating NSCs. We examined both apoptosis and mitosis and found that rotenone decreased apoptosis as detected by staining cleaved caspase-3 but did not affect mitosis. Our results suggest that functional mitochondria are necessary in both the proliferation and differentiation of SVZ NSCs. Furthermore, mitochondria might be involved in the mitosis and apoptosis that occur during those processes.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.3
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• pp.166-171
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• 2023

Efficient energy management is a very important factor in sensor networks with limited resources, and cluster techniques have been studied a lot in this respect. However, a problem may occur in which energy use of the cluster header is concentrated, and when the cluster header is not evenly distributed over the entire area but concentrated in a specific area, the transmission distance of the cluster members may be large or very uneven. The transmission distance can be directly related to the problem of energy consumption. Since the energy of a specific node is quickly exhausted, the lifetime of the sensor network is shortened, and the efficiency of the entire sensor network is reduced. Thus, balanced energy consumption of sensor nodes is a very important research task. In this study, factors for balanced energy consumption by cluster headers and sensor nodes are analyzed, and a balancing distribution clustering method in which cluster headers are balanced distributed throughout the sensor network is proposed. The proposed cluster method uses multi-hop routing to reduce energy consumption of sensor nodes due to long-distance transmission. Existing multi-hop cluster studies sets up a multi-hop cluster path through a two-step process of cluster setup and routing path setup, whereas the proposed method establishes a hierarchical cluster routing path in the process of selecting cluster headers to minimize the overhead of control messages.

• Clinical and Experimental Pediatrics
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• v.51 no.4
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• pp.343-350
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• 2008

Asthma and allergic diseases are one of the most common disorders in children. Due to its increased prevalence, as well as the increased morbidity and mortality from these diseases, asthma and allergic diseases have come to be recognized as a major worldwide public health issue. In addition, socioeconomic burden of asthma and allergic diseases has increased in Korea also. The International Study of Asthma and Allergies in Childhood (ISAAC) investigated the worldwide prevalence of asthma and other allergic diseases using simple standardized methods because of the comparison of asthma and allergic diseases between the countries. In Korea, several epidemiologic studies have been conducted to determine the prevalence of asthma in children. Although these studies showed increased prevalence of asthma among Korean children (from 3.4% in 1964 to 10.1% in 1989), these findings were based on data from small numbers of subjects. The first Nationwide Study of Asthma and Allergies in Korean Children, which utilized the Korean version of ISAAC written and video questionnaire, was conducted in 1995 and the second Nationwide Study of Asthma and Allergies in Korean Children was conducted in 2000, directed by the Korean Academy of Pediatric Allergy and Respiratory Diseases. We report here the prevalence of asthma and other allergic diseases in Korean children and adolescents, and show the changes that occurred over this 5 year period. We also describe the risk factors for development of these diseases in Korean children. We developed Korean versions of the ISAAC written (WQ) and video (AVQ) questionnaires for allergic diseases. In 1995, the enrolled population consisted of 25,117 children selected from 34 elementary school and 14,946 children selected from 34 middle school across the nation, the response rate was 94.8%. In 2000, 27,831 children selected from 34 elementary school and 15,214 children selected from 34 middle school, and the response rate was 96.4%. From these studies, we can confirm that increase of the prevalences of asthma, allergic rhinitis, and atopic dermatitis in Korea, except the prevalence of food allergy. Especially, the video questionnaire showed increases in the lifetime and 12 month prevalence rates of wheeze at rest, exercise-induced wheeze, nocturnal wheeze, nocturnal cough, and severe wheeze over this period of time in middle school children. In addition, the increase of prevalences of symptoms, diagnosis and treatment of atopic dermatitis was noted significantly. Risk factor analysis showed that body mass index (BMI), passive smoking and living with a dog or cat were associated with higher risk of wheeze. Also the occurrence of fever during infancy and the frequent use of antibiotics were associated with the risk of wheeze. In conclusion, during the 5 year period from 1995 to 2000, the prevalences of asthma, allergic rhinitis, and atopic dermatitis has increased in Korean children. BMI, passive smoking, living with a dog or cat, the fever episodes in infancy, and the frequent use of antibiotics in infancy are important risk factors to development of asthma and atopic dermatitis. In the near future, the birth cohort study will be needed to investigate the causes of this increase and the natural course of allergic diseases, then we develop the methods to control asthma and allergic diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1592-1599
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• 2013

Despite numerous studies regarding overweight or obese children, only a limited number of studies have investigated the effect of underweight. The purpose of this study is to investigate the determinants of underweight among school-aged children. A total of 493 students (86 underweight and 407 normal weight students) aged 11 to 13 years were included in our study. Socio-demographic characteristics, eating habits, health information, self-perception of weight, weight-control efforts and birth-related information were collected by using survey questionnaires for children and parents. Dietary information was obtained by two 24-hour food records, which were completed by both children and their parents. The prevalence of underweight was significantly higher in girls than boys, and the frequency of medical treatment and flu symptoms were higher in underweight children than normal ones. Overall, girls tended to overestimate their own weight; this misclassification was greater among underweight girls. Birthweight was positively correlated with current weight (P<0.05) and height (P<0.01) in girls, but these correlations were not seen in boys. In conclusion, underweight girls had inappropriate self-perception of weight, and underweight in girls may be related with birthweight and inadequate dietary intakes. Therefore, it is important to build a well-designed framework that integrates efforts of home, school, and community to maintain a healthy weight with balanced diet and exercise throughout the lifetime.

• Journal of Energy Engineering
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• v.29 no.2
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• pp.68-78
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• 2020

According to the new climate change agreement, technology development to reduce greenhouse gases is actively conducted worldwide, and research on energy efficiency improvement in the field of power generation and transmission and distribution is underway [1,2]. Economic analysis of the operation method of storing and supplying surplus electricity using energy storage devices, and using energy storage devices as a frequency adjustment reserve power in regional cogeneration plants has been reported as the most profitable operation method [3-7]. Therefore, this study conducted an economic analysis for the installation of energy storage devices in the combined heat and power plant in the Czech Republic. The most important factor in evaluating the economics of battery energy storage devices is the lifespan, and the warranty life is generally 10 to 15 years, based on charging and discharging once a day. For the simulation, the ratio of battery and PCS was designed as 1: 1 and 1: 2. In general, the primary frequency control is designed as 1: 4, but considering the characteristics of the cogeneration plant, it is set at a ratio of up to 1: 2, and the capacity is simulated at 1MW to 10MW and 2MWh to 20MWh according to each ratio. Therefore, life was evaluated based on the number of cycles per year. In the case of installing a battery energy storage system in a combined heat and power plant in the Czech Republic, the payback period of 3MW / 3MWh is more favorable than 5MW / 5MWh, considering the local infrastructure and power market. It is estimated to be about 3 years or 5 years from the simple payback period considering the estimated purchase price without subsidies. If you lower the purchase price by 50%, the purchase cost is an important part of the cost for the entire lifetime, so the payback period is about half as short. It can be, but it is impossible to secure profitability through the economy at the scale of 3MWh and 5MWh. If the price of the electricity market falls by 50%, the payback period will be three years longer in P1 mode and two years longer in P2 and P3 modes.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.180-193
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• 2014

In plants, a shoot apex has a small region known as the shoot apical meristem (SAM) having a group of dividing (initiating) cells. The SAM gives rise to all the groundabove structures of plants throughout their lifetime, and thus it plays important role in growth and development of plants. This review describes theories to explain the SAM organization and function developed over the last 250 years. Since in 1759 German botanist C. F. Wolff has described firstly the SAM, in 1858 Swiss botanist C. N${\ddot{a}}$geli proposed the apical cell theory from the observation of a large single apical cell in the SAM of seedless vascular plants: however, this view was recognized to be unsuitable to seed plants. In 1868, German botanist J. Hanstein suggested the histogen theory: this concept subdividing the SAM into dermatogen, periblem, and plerome was unable to generally apply to seed plants. In 1924, German botanist A. Schmidt proposed the tunica-corpus theory from the examination of angiosperm SAM in which two parts show different planes of cell division: this theory was proved to be not suitable to gymnosperm SAM, not have stable surface tunica layer. In 1938, American botanist A. Foster described zones in gymnosperm SAM based on the cytohistologic differentiation and thus called it a cytohistological zonation theory. With works by E. Gifford, in 1954, this zonation pattern was demonstrated to be also applicable to angiosperm SAM. As another theory, in 1952 French botanist R. Buvat proposed the m${\acute{e}}$rist${\grave{e}}$me d'attente (waiting meristem) theory: however, this concept was confuted because of its negation of function during vegetative growth phase to central initial cells. Rescent studies with Arabidopsis thaliana have found that formation and maintenance of the SAM are under the control of selected genes: SHOOTMERISTEMLESS (STM) gene forms the SAM, and WUSCHEL (WUS) and CLAVATA (CLV) genes function in maintaining the SAM; signaling between WUS and CLV genes act through a negative feedback loop.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.209-213
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• 2019

Recently, demand for high energy density and long cycling stability of energy storage system has increased for application using with frequency regulation (F/R) in power grid. Supercapacitor have long lifetime and high charge and discharge rate, it is very adaptable to apply a frequency regulation in power grid. Supercapacitor can complement batteries to reduce the size and installation of batteries. Because their utilization in a system can potentially eliminate the need for short-term frequent replacement as required by batteries, hence, saving the resources invested in the upkeep of the whole system or extension of lifecycle of batteries in the long run of power grid. However, low energy density in supercapacitor is critical weakness to utilization for huge energy storage system of power grid. So, it is still far from being able to replace batteries and struggle in meeting the demand for a high energy density. But, today, LIC (Lithium Ion Capacitor) considered as an attractive structure to improve energy density much more than EDLC (Electric double layer capacitor) because LIC has high voltage range up to 3.8 V. But, many aspects of the electrochemical performance of LIC still need to be examined closely in order to apply for commercial use. In this study, in order to improve the capacitance of LIC related with energy density, we designed new method of pre-doping in anode electrode. The electrode in cathode were fabricated in dry room which has a relative humidity under 0.1% and constant electrode thickness over $100{\mu}m$ was manufactured for stable mechanical strength and anode doping. To minimize of contact resistance, fabricated electrode was conducted hot compression process from room temperature to $65^{\circ}C$. We designed various pre-doping method for LIC structure and analyzing the doping mechanism issues. Finally, we suggest new pre-doping method to improve the capacitance and electrochemical stability for LIC.