• Asian Journal of Atmospheric Environment
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• v.12 no.1
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• pp.17-29
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• 2018

For the first time in the city of Riyadh, the formation of $O_3$ and its relationship with NO and $NO_2$ ($NO_x$) was investigated. Throughout the summer $O_3$, NO, and $NO_2$ were collected from three locations: residential, industrial, and rural areas. During the sampling period $O_3$ concentrations exceeded 1-hour local standards a few times yet remained consistent with the standards most of the time. The $O_3$ concentrations were observed highest in the rural location and lowest in the industrial area. The diurnal variation of NO followed a double peak: one in the morning and the other in the evening, representing the traffic pattern. Early morning NO peaks were observed in the rural location, which were attributed to the movement of NO from other locations. The $O_3$ concentrations depicted typical pattern, increasing after sunrise and reaching its maximum during midday. The highest $O_3$ concentrations were observed in the rural location followed by the residential and industrial. $NO_2$ photolysis rates were 3-4 times higher compared to other similar investigations, potentially due to intense solar radiation. A strong negative correlation was observed between $NO_x$ and $O_3$ values in the industrial location indicating photochemical activities around the industrial area were higher, likely due to additional $NO_x$ emissions from industries. Regression analysis of $NO_x$ and OX ($O_3+NO_2$) indicated that in residential and industrial locations at nighttime there were large $NO_x$ independent regional contributions which is attributed to VOCs. The Weekend Effect was observed in the city potentially due to the production of the OH radical and subsequent reactions with VOCs implying that the area is VOC-sensitive.

• Nutrition Research and Practice
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• v.7 no.6
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• pp.488-494
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• 2013

A food allergy is an adverse health effect arising from a specific immune response that occurs reproducibly upon exposure to a given food. In those with food allergies that are thought to cause aggravation of eczema, food avoidance is important. The objective of this study was to research the nutritional status of patients with food allergies. A total of 225 subjects diagnosed with atopic dermatitis underwent a skin prick test as well as measurement of serum immunoglobulin E. Food challenge tests were conducted using seven food items: milk, eggs, wheat, soybeans, beef, pork, and chicken. At post-food challenge visits to the test clinic, participants completed a three-day dietary record, which included two week days and one weekend day, in order to evaluate energy intake and diet quality during the challenge. We analyzed nutrient intake based on differential food allergens. Subjects with a food allergy to milk showed lower intake of Ca, Zn, and vitamin B2, and subjects with a food allergy to egg showed lower intake of vitamin A, B1, B2, niacin, and cholesterol. Subjects with a food allergy to wheat and soybean showed lower intake of Ca, P, Fe, K, Zn, vitamin B2, vitamin B6, and niacin; and subjects with a food allergy to beef, pork, and chicken showed lower intake of Fe and higher intake of K, vitamin A, B2. Subjects with atopic dermatitis were lacking in several nutrients, including vitamin A and vitamin C. A greater number of food allergies showed an association with a greater number of nutrient intake deficiencies. Allergen avoidance is the basic treatment for atopic dermatitis. However, when the allergen is food, excessive restriction can lead to nutrition deficiency. Findings of this study suggest the necessity for enhanced nutritional education in order to provide substitute foods for patients with food allergies who practice food restriction.

• Journal of Family Resource Management and Policy Review
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• v.19 no.3
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• pp.121-142
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• 2015

The purpose of this study is to resolve the factors that affect happiness levels and leisure life satisfaction of middle-class and to find way to incorporate them into policy. In this study, a status analysis on leisure life and One-Way ANOVA conduct a study on leisure resource and income levels that affect the happiness level and leisure life satisfaction. To recap briefly, to reduce the social and cultural polarization caused by economic disparity and to promote leisure life satisfaction and happiness level is possible quantitative-qualitative growth and maturation of middle class. The most important thing here is increasing in leisure time and leisure costs that consumed in real leisure life. In other words, leisure life satisfaction and happiness levels in the middle class has seen a significant difference in depending on whether and how much to spend on leisure time and cost, rather than differences of the monthly average household income. More particularly, analysis results seem to hoping of the extra leisure costs about 50,000 won per person and increasing the leisure time on weekdays and long weekend holiday. Above all, It is important to redefine the middle class that meets the recognition of the people and it should reflect government policy. Ultimately, The state of the socio-economic-welfare policies will be further expanded in the direction for the middle class, thinking of themselves as middle class and leading national consciousness.

• Journal of the Korean Society for Railway
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• v.14 no.5
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• pp.470-476
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• 2011

This study proposed the intervention ARIMA model as a way to forecast the KTX passenger demand. The second phase of the Gyeongbu high-speed rail project and the financial crisis in 2008 were analyzed in order to determine the effect of time series on the opening of a new line and economic impact. As a result, the financial crisis showed that there is no statistically significant impact, but the second phase of the Gyeongbu high-speed rail project showed that the weekday trips increased about 17,000 trips/day and the weekend trips increased about 26,000 trips/day. This study is meaningful in that the intervention explained the phenomena affecting the time series of KTX trip and analyzed the impact on intervention of time series quantitatively. The developed model can be used to forecast the outline of the overall KTX demand and to validate the KTX O/D forecasting demand.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.161-171
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• 2019

Varied methods have been researched continuously because the past as the daily maximum electricity demand expectation has been a crucial task in the nation's electrical supply and demand. Forecasting the daily peak electricity demand accurately can prepare the daily operating program about the generating unit, and contribute the reduction of the consumption of the unnecessary energy source through efficient operating facilities. This method also has the advantage that can prepare anticipatively in the reserve margin reduced problem due to the power consumption superabundant by heating and air conditioning that can estimate the daily peak load. This paper researched a model that can forecast the next day's daily peak load when considering the influence of temperature and weekday, weekend, and holidays in the Seasonal ARIMA, TBATS, Seasonal Reg-ARIMA, and NNETAR model. The results of the forecasting performance test on the model of this paper for a Seasonal Reg-ARIMA model and NNETAR model that can consider the day of the week, and temperature showed better forecasting performance than a model that cannot consider these factors. The forecasting performance of the NNETAR model that utilized the artificial neural network was most outstanding.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.3
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• pp.205-216
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• 2017

Carbonaceous aerosols such as the equivalent black carbon (eBC), the elemental carbon (EC) and the organic carbon (OC) were monitored at the Seoul Olympic Park site ($37.521^{\circ}N$, $127.124^{\circ}E$) during the KORUS-AQ 2016 campaign using a Multi Angle Absorption Photometer (MAAP) and an OCEC Analyzer. Averaged mass concentrations of eBC, EC and OC were presented as $2.46{\pm}1.52{\mu}g/m^3$, $1.01{\pm}0.60{\mu}g/m^3$ and $4.85{\pm}2.60{\mu}g/m^3$, respectively. OC/EC ratio and mass absorption cross-section (MAC) of light absorbing aerosols were calculated as 2.32 and $14.8m^2/g$, respectively. Diesel OC concentrations were estimated from a source profile of diesel vehicles as well. eBC mass concentrations measured from May $26^{th}$ to May $27^{th}$, 2016 showed 40% higher than averaged eBC mass concentrations during campaign period. $PM_{2.5}$ concentrations measured in this period were also higher than average $PM_{2.5}$ concentrations. High eBC concentrations were observed from May $29^{th}$ to May $31^{st}$, 2016 and from June $9^{th}$ to June $11^{th}$, 2016, possibly due to morning rush hour and the effect of temperature inversion at night. Diurnal variations of eBC, EC and Diesel OC showed a typical pattern of metropolitan area. In the weekend, however, diurnal variations of eBC, EC and Diesel OC mass concentrations were different from those measured in the weekday. It is expected that this study can help to understand the relationship between carbonaceous aerosols in a metropolitan area.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.111-121
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• 2017

Smartphone use has become a part of everyday life, not only for adolescents but also for elderly and older people. Thus, this study explored the effect of demographic variables, the amount of smartphone usage, type of smartphone use and psychosocial variables on smartphone dependence of the elder group. We analyzed the data of 5627 (50s and 60s) of the Internet overdependence survey data of the Korea Information Society Agency in 2016. As a result of hierarchical multiple regression analysis, More frequency of smartphone use of weekday and weekend, and usage time of smartphone of weekday were related to greater smartphone dependence. More smartphone use for information seeking and games were associated with greater smartphone dependence. And, as loneliness and anxiety increased, smartphone dependence increased, while smartphone dependence decreased, as social capital increased. Through this study, it is necessary to understand characteristics related to smartphone dependence of elder and older group, and to use this knowledge to solve their smartphone dependence. Future studies also need to identify the causal relationship between predictors of smartphone dependence in elderly and older people.

• The Journal of Fisheries Business Administration
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• v.40 no.2
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• pp.49-70
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• 2009

This study proviedes GARCH model(Bollerslev, 1986) to analyze the structural characteristics of price volatility in domestic aquacultural fish market of Korea. As a case study, flatfish and rock-fish are analyzed as major species with relatively high portion in an aspect of production volume among fish captured in Korea. For analyzing, this study uses daily market data (dating from Jan 1 2000 to June 30, 2008) published by the Noryangjin Fisheries Wholesale Market which is located in Seoul of Korea. This study performs normality test on trading volume and price volatility of flatfish and rock-fish as an advanced empirical approach. The normality test adopted is Jarque-Bera test statistic. As a result, first, a null hypothesis that "an empirical distribution follows normal distribution" was rejected in both fishes. The distribution of daily market data of them were not only biased toward positive(+) direction in terms of kurtosis and skewness, but also characterized by leptokurtic distribution with long right tail. Secondly, serial correlations were found in data on market trading volume and price volatility of two species during very long period. Thirdly, the results of unit root test and ARCH-LM test showed that all data of time series were very stationary and demonstrated effects of ARCH. These statistical characteristics can be explained as a reasonable ground for supporting the fitness of GARCH model in order to estimate conditional variances that reveal price volatility in empirical analysis. From empirical data analysis above, this study drew the following conclusions. First of all, from an empirical analysis on potential effects of seasonality and the day of week on price volatility of aquacultural fish, Monday effects were found in both species and Thursday and Friday effects were also found in flatfish. This indicates that Monday is effective in expanding price volatility of aquacultural fish market and also Monday has higher effects upon the price volatility of fish than other days of week have since it has more new information for weekend. Secondly, the empirical analysis led to a common conclusion that there was very high price volatility of flatfish and rock-fish. This points out that the persistency parameter($\lambda$), an index of possibility for current volatility to sustain similarly in the future, was higher than 0.8-equivalently nearly to 1-in both flatfish and rock-fish, which presents volatility clustering. Also, this study estimated and compared and model that hypothesized normal distributions in order to determine fitness of respective models. As a result, the fitness of GARCH(1, 1)-t model was better than model where the distribution of error term was hypothesized through-distribution due to characteristics of fat-tailed distribution, was also better than model, as described in the results of basic statistic analysis. In conclusion, this study has an important mean in that it was introduced firstly in Korea to investigate in price volatility of Korean aquacultural fishery products, although there was partially a limited of official statistic data. Therefore, it is expected that the results of this study will be useful as a reference material for making and assessing governmental policies. Also, it is looked forward that the results will be helpful to build a fishery business plan as and aspect of producer, and also to take timely measures to potential price fluctuations of fishery products in market. Hence, it is advisable that further studies related to such price volatility in fishery market will extend and evolve into a wider variety of articles and issues in near future.

• Journal of Family Resource Management and Policy Review
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• v.17 no.4
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• pp.19-37
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• 2013

From the perspective of labor welfare, forty-hour-a-week working system:(FWS) has been an important goal throughout world, and in fact, advanced countries implemented this a long time ago. However, there are differences in opinions concerning FWS; some people emphasizes the improvement in life quality, while others point out that this measure increases the cost of wages and has limited effectiveness. Thus, discussions about the success of FWS have emerged from diverse perspectives; One thing that should be made clear before debating FWS is that reducing laborers' working hours is already a global trend, and Korea, also intends to extend it. Therefore, in order to maximize the benefits resulting from the execution of the system and to identify measures that can be used to solve the problems related to FWS, it is necessary to consider actual laborers' use of leisure resources and whether they have increased or decreased as a result of FWS. It is also necessary to look at the differences in workers' leisure activity with and without the system. To evaluate and diagnose FWS's political effect from the perspective of laborers' leisure satisfaction and improvements in life quality, this study examines differences in leisure expenses, leisure hours, use of and demand for leisure resources such as leisure space, and types of leisure activity, according to the execution of FWS, This research is based on the "2012 Survey on National Leisure Activity" conducted by the Ministry of Culture, Sports and Tourism. In addition, through analysis of the differences in leisure satisfaction and happiness levels, the study intends to confirm the necessity of executing FWS and ensuring that the system is in use. The study results can be briefly summed up as followa:: First, regarding the general findings of the study, a significant result was shown in terms of the execution of FWS according to income level. The finding that the execution of FWS works differently according to the working environment or life quality reassures us of the common notion in society that working environment or life quality may differ in relation to social characteristics. The utility of weekday leisure hours did not indicate a statistically significant difference, but in terms of weekend leisure hours, laborers practicing FWS had an additional 30 minutes of leisure time than those who did not. Furthermore, regarding leisure expenses, laborers practicing FWS indicated more monthly average leisure expenses or expected leisure expenses. In relation to leisure activity, those working at a company executing FWS engaged in culture and art activities more frequently than those working at the companies that did not. On the other hand, those working at companies without FWS indicated more hobbies, amusement activities, rest, and other activities than those working at the companies with FWS. In terms of vacation experience, those working at companies with FWS had more vacation time than those working at companies without it; on average, they had longer vacations by 1.64 days. Regarding their leisure life satisfaction and happiness level, those working at companies with FWS indicated higher satisfaction and greater happiness than those working at companies without it. The findings mentioned above represent the preliminary results of this paper, and the remainder of the research will provide more detailed analysis results and suggestions corresponding to them.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.20-28
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• 2014

The three air quality monitoring sites, analysed simultaneously PM-10 and PM-2.5, ie. Ihyeondong in industrial area, Manchondong in residential area, Pyeongnidong in streetside, among 13 air quality monitoring sites in Daegu area, were investigated the concentration distribution characteristics of PM-2.5 and PM-10 in the last 2 years (2011~2012). PM-10 concentrations exceeded annual average reference value ($50{\mu}g/m^3$) in Ihyeondong ($52.5{\mu}g/m^3$) and Pyeongnidong ($60.9{\mu}g/m^3$) but satisfied in Manchondong ($44.9{\mu}g/m^3$). All PM-2.5 concentrations exceeded EPA annual standard value of the United States ($15{\mu}g/m^3$) in three points, but also exceeded new control annual standard value ($25{\mu}g/m^3$) coming into effect in 2015. Seasonal concentration of PM-10 appeared the order of spring > winter > fall > summer, and in the case of PM-2.5, the order was winter > spring > fall > summer. Monthly concentrations of PM-10 and PM-2.5 were highest in February and lowest in September. Diurnal concentrations of PM-10 and PM-2.5 increased from 7:00 AM, and recorded the highest concentration between 10:00 AM and 11:00 AM. And after 6:00 PM it lowered continuously and tended to show fixed concentrations from evening until early morning. In addition, the concentration of fine particles during the week was higher than the weekend. The fluctuation in industrial area was larger than the residential area. At the PM-2.5/PM-10 ratio, summer was generally high, spring was the lowest. And, when yellow sand occurred, it was 0.32 to 0.42. It was very low compared to 0.54 to 0.64 during non-yellow sand times. This paper for the state and the characteristics of Daegu' fine particles (PM-10, PM-2.5) will be valuable to future researches of fine particles and air pollution management.