• Journal of the Korean earth science society
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• v.23 no.5
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• pp.424-435
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• 2002

This study analyzes the surface ozone and meteorological data in Daegu for a period from 1997 to 1999. It also investigates the meteorological characteristics of high ozone episodes. For this study the high ozone episode has been defined as a daily maximum ozone concentration higher than 100ppb in at least one station among six air quality monitoring stations in Daegu, Korea. The frequency of episodes is 13 days. The frequency is the highest in May and September. The average value of daily maximum ozone concentration is 81.6ppb, and 8-hour average ozone concentration is 58.6ppb for the high episodes. This shows that ozone pollution is continuous and wide-ranging in Daegu. The daily maximum ozone concentration is positively correlated to solar radiation and daily maximum temperature, but negatively correlated to relative humidity, wind speed and cloud amount. The maximal correlation coefficient to solar radiation is 0.45. The differences between high ozone episode day's daily mean meteorological value and monthly mean value are +1.58hPa for sea level pressure, +3.45${\circ}$C for maximum temperature, -5.69% for relative humidity, -0.46ms$^{-1}$ for wind speed, -1.79 for cloud amount, and +3.97MJm$^{-2}$ for solar radiation, respectively. This shows that strong solar radiation, low wind speed and no precipitation between 0700${\sim}$1100LST are favorite conditions for high ozone episodes. It is related to the morning stagnant condition.

• Journal of the Korean earth science society
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• v.30 no.2
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• pp.210-222
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• 2009

Lightning data, observed from total lightning detection system (TLDS) of KMA, for the recent five years (2002-2006) have been analyzed for temporal and spatial characteristics of frequency, intensity, duration, and flash rate. Lightning frequency varies largely with years (most frequent in 2006) and the lightning during the summer accounts for 75% of total flashes and only 0.6% of lightnings strike in cold season. In rainy season (JJAS), the ratio of positive flashes to negative ones is as low as 0.15, but it increases up to 0.98 in February. The seasonal variation of lightning duration is strongly linked with lightning occurrences, whereas flashes rates show weak seasonal variability. In a daily scale, lightning, on average, occurs more often at dawn (2 am, 5-7 am) and in the mid-afternoon (15 pm), and the lightning at dawn (around 5 am) is most intense during the day. The western inland areas md the West/South Sea show high lightning density during JJAS, whereas eastern part and the East Sea exhibit a low density of lightning. Considering the low ratio of positive flashes (0.15) for the whole analysis domain during summer period, Chungnam and Jeonbuk areas have a high ratio of flashes over 0.4. However, these should be analyzed with much caution because weak positive cloud-to-cloud discharges can be regarded as cloud-to-ground flashes. The western inland also exhibits long annual flash hours (15-24). And the W3st Sea has high flash rates as a result of large density and low flash hours. The most frequent time of lightning occurrence over most inland areas lies between mid-afternoon and early-evening, whereas mountainous and coastal areas, and the northern Kyoungki and Hwanghae provinces show the maximum lightning strikes in the morning and at dawn, respectively.

• Journal of Korean Elementary Science Education
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• v.24 no.2
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• pp.103-110
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• 2005

The purpose of this study was to investigate the relation between the learning styles and science process skills of students of the gifted class in elementary school. Subjects were forty-eight students of the gifted class who are in the fifth grade studying at the gifted class of S elementary school in Bucheon, M and Y elementary school in Incheon on learning styles and science process skills of students. Learning Style Profile (LSP) was used as instrument to survey learning style of students of the gifted class which was developed by NASSP, and consists of four categories (cognitive skills, perceptual response, orientation and teaming preferences) and twenty-four subscales. The results of this study were as follows: 1. In the learning styles test, students of the gifted class have higher scores of spatial skill, sequential processing skill, persistence orientation, manipulative preference, temperature preference and afternoon preference than general class students, but they have lower scores of discrimination skill and lighting preference, and there were statistically significant difference. 2. In science process skills test, there were statistically significant difference between students of the gifted class and general students. 3. In the correlation between the learning styles and science process skills, there was positive correlation of observing skill with spatial skill and manipulate skill of cognitive skill domain. For classifying skill, there was positive correlation with visual perceptual response, but was negative correlations with auditory and emotive perceptual response of perceptual response domain and with evening preference and verbal risk orientation of study preference domain. For measuring skill, there was positive correlation with sequential processing skill of cognitive skill domain. For formulating hypotheses, there was controlling variables, there was positive correlation with sequential processing skill and simultaneous processing skill of cognitive skill domain, and with verbal-spatial preference and early morning study preference of study preference domain. When planning and managing the gifted class, it will be beneficial and effective to consider the meaningful relations between the elements of loaming style and science process skills in order to improve science process skills.

• Korean Journal of Psychosomatic Medicine
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• v.18 no.1
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• pp.30-39
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• 2010

Objectives：Assessment of sleep disturbance is an essential part of the diagnostic criteria used for several psychiatric disorders. Change in sleep patterns over time may indicate response to treatment. In clinical practice, sleep is usually evaluated subjectively by patient self-report. This study was aimed to compare subjective sleep assessment with objective sleep measurement by actigraphy in psychiatric inpatients. Methods：A total of 32 psychiatric inpatients were studied. Patients were asked to wear a wrist actigraphy for three consecutive days and nights and to fill out a sleep log each morning. The severity of depression and anxiety was evaluated according to Beck Depression Inventory and State-Trait Anxiety Inventory on the first day of the study. The subjective level of satisfaction with quality of sleep was also evaluated according to visual analog scale. Nurses assessed sleep at one hour interval between 10:00 PM and 6:00 AM for three consecutive nights. Results：There was statistically significant difference of sleep latency between patient's sleep log and acti-graphic measurement. Nursing reports were more consistent with actigraphic measurement than sleep log. Interestingly, subjectively poor sleepers show no significant difference in sleep parameters compared with those of good sleepers. Subjectively poor sleepers report longer sleep latency than that of actigraphic assessment. The discrepancy between subjective and objective assessment of sleep latency was significantly correlated with scores of Beck Depression Inventory and State-Trait Anxiety Inventory. Conclusion：These results show that there are discrepancies between subjective and objective assessment of sleep. The discrepancy of sleep assessment could be influenced by severe depression and anxiety. Especially objective sleep measurement is needed to assess sleep in psychiatric inpatients with severe depression or anxiety and the subjectively poor sleepers for more reliable measurements.

• Journal of the Korean association of regional geographers
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• v.3 no.1
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• pp.13-34
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• 1997

The impact of a central place on daily living over wide outlying territory has been one of traditional subjects in the field of urban geography. The flow of rural population toward the central city of Chinju characterizes the population movement in Western Kyungnam, where the spillover of urban population into outlying areas, an especially prominent phenomenon in American society, does not occur. The central city of Chinju is supposed to be the most favored settlement area in Western Kyungnam. More than two thousands of teachers. who live in Chinju, cross the city boundary each morning to do their jobs in Western Kyungnam. But only ninety teachers living outside Chinju commute to the workplace in the city. The teachers willingly spend hours commuting each day to enjoy better quality of life in the central city. In fact, the central city of Chinju functions as bedroom communities for many middle-class workers in Western Kyungnam. On the basis of teachers' commuting behavior, four levels of Chinju's urban spheres are identified in Western Kyungnam. As Table-6 and Figure-2 show, the first-order level of Chinju's sphere includes most Myuns of Sanchung/Hadong Guns and some Myuns of Sachun/Gosung Guns. The second-order level comprises Sanchung/Sachun Eubs and many Myuns of Sachun /Gosung Guns. The third-order level is made up of Samchunpo, Hadong/Gosung/Eryung/Namhae/Habchun/Hamyang Eups, and many Myuns of Eryung/Namhae/Habchun Guns. And all of Guchang Gun and most Myuns of Hamyang Gun belong to the fourth-order level of Chinju's sphere. The influence sphere of Metropolitan Chinju is extended farther in the direction of less competition with other metropolises. Such a situation occurs to the west and south of Chinju. Daily commuting, defined as the journeys to and from work, is an excellent indicator for delimiting urban spheres of influence.

• The Journal of Engineering Geology
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• v.18 no.2
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• pp.191-196
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• 2008

This study is a case study for application of the RTI warning model to Korea which was previously developed to predict landslide potential and occurrence time during a rainfall event. The rainfall triggering index (RTI) is defined as the product of the rainfall intensity I (mm/hr) and the effective accumulated rainfall $R_t$ (mm). This index is used to evaluate the landslide and debris-flow occurrence potential at time t during a rainfall event. The upper critical value ($RTI_{UC}$) of RTI and the lower critical value ($RTI_{LC}$) of RTI can be determined by historical rainfall data of a certain area. When the rainfall intensity exceeds the upper critical value, there are high potential to occur land-slides. The analysis result can predict landslide occurrence time of an area during a rainfall event as well as land-slide potential. The result can also be used as an important data to issue early-warning of landslides. In order to apply the RTI warning model to Korea this study analyzed rainfall data and landslides data in Inje county, Gangwon province, Korea from July 13 to July 19, 2006. According to the analysis result, the rainfall intensity exceeded the upper critical value 23 hours ago, 11 hours ago, and 9 hours ago from 11:00 in the morning, July 16. Therefore, landslide warnings would be issued three times for people evacuation for avoiding or reducing hurts and dam-ages from landslides in mountainous areas of Inje.

• Korean Journal of Community Nutrition
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• v.13 no.4
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• pp.476-488
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• 2008

This study investigates the relationship of smoking on daily intake of nutrients and snacks in the Chungnam and Daejeon high school students. Up to date scientific nutrition education and counseling programs in the regular school system is needed for a professional nutrition education teacher. The primary objective of this study was to provide useful information to nutrition education teachers. A survey was conducted with 400 high school students in the Chungnam and Daejeon areas. 381 out of 400 questionnaires were analyzed with SPSS 12.0K. The subjects were composed of 49.8% male, 50.1% female and 40.9% regular high school students, 59.1% business high school students and smokers 43.1%, non-smokers 56.9%. 43.4% of smokers had been smoking since middle school. On analysis of daily nutrient intakes, 16 out of 19 nutrients except animal calcium, Vitamin A and Vitamin C were much more consumed by the smoking group than the non-smoking group non-significantly. Especially vegetable fat and Vitamin E were higher in the smoking group than the non-smoking group (p<0.05). The intake ratio of carbohydrates: protein: fat was similar in the two groups (smoking group 55:15:29, nonsmoking group 56:15:28). Intakes of Vitamin B1 and potassium in comparison with the Korean dietary reference intakes(KDRI) were under 50% in both groups. However, sodium was taken over 200% compared to KDRI in both groups. Intakes of Vitamin C in the smoking group were as low as 76.5% in comparison to KDRI. Smokers need to increase the intakes of Vitamin C considering that smokers need to intake Vitamin C two times than non-smokers. Nutrient intakes from snacks in the smoking group were higher than the non-smoking group. Nutrients that originated from snacks which took over 20% among daily nutrient intakes were 12 nutrients(energy, fat, carbohydrate, calcium, P, Fe, K, Vitamin $B_1$, Vitamin $B_2$, Vitamin C, Vitamin E, dietary fiber) in the smoking group compared to 7 nutrients(energy, vegetable protein, fat, carbohydrate, calcium, Vitamin $B_2$, Vitamin C) in the non-smoking group. The smoking group was significantly paying more money for snacks each month than the non-smoking group was(p<0.01). Periods of consumption were irregular in the smoking group(p<0.05) and the smoking group was used to taking snacks in the morning compared to the non-smoking group. The smoking group preferred sweets and high calorie food over other snacks in comparison of the non-smoking group. The nonsmoking group had better eating habits than the smoking group.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.151-158
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• 2010

In order to measure the deposition velocity of $I_2$ vapor for radish plants and its translocation factor for their roots, radish plants were exposed to $I_2$ vapor for 80 min. at different growth stages between 29 and 53 d after sowing. The exposure was performed in a transparent chamber during the morning time. Deposition velocities ($ms^{-1}$) were on the whole in the range of $1.0{\times}10^{-4}{\sim}2.0{\times}10^{-4}$ showing an increasing tendency with an increase in the biomass density. The results showed some agreement with existing reports that a higher relative humidity would lead to a higher deposition velocity. The acquired deposition velocities were lower than by factors of several tens than some field measurements probably due to a very low wind speed (about $0.2\;ms^{-1}$) in the chamber. Translocation factors (ratio of the total iodine in the roots at harvest to the total plant deposition), estimated in a more or less conservative way, were $1.3{\times}10^{-3}$ for an exposure at 29 d after sowing and $5.0{\times}10^{-3}$ for an exposure at 53 d after sowing. In using the present experimental data, meteorological conditions and chemical and physical forms of iodine need to be carefully considered.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.69-76
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• 2008

Three failure cases of CNG composite vessels were reported since after January 2005. The 1st and 2nd accidents were indebted to vessel defect and installation mistake. The 3rd was caused by gas leak at pipe connections. In this paper various aspects were studied based on information of the three failure analysis, which must be improved for better safety of the CNG bus system. Overpressure region caused by vessel explosion was theoretically predicted and also assessed by PHAST program. Explosion of 120 l vessel under 20 MPa is equivalent to 1.2 kg TNT explosion. The predicted value by PHAST was more serious than theoretical one. However, actual consequence of explosion was much less than both of the predicted consequences. Since the CNG vessel was designed by the performance based design methodology, it is difficult to verify whether the required process and tests were properly conducted or not after production. If material toughness is not enough, the vessel should be weak in brittle fracture at early in the morning of winter season since the metal temperature can be lower than the transition temperature. If autofrettage pressure is not correct, fatigue failure due to tensile stress during repeated charging is possible. One positive aspect is that fire did not ocurred after vessel failure. This may be indebted to fast diffusion of natural gas which hindered starting fire.

• Journal of Korean Society of Transportation
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• v.35 no.3
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• pp.210-219
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• 2017

Electric vehicles, which are attracting attention as eco-friendly vehicles, have been increasing in number since 2011 in Korea. The purpose of this study is to analyze the efficient operation of existing charging stations and factors to consider when installing additional charging stations based on the case of Jeju Island where the electric vehicle penetration rate is high and the charging infrastructure is relatively well established. The characteristics of using electric car charging stations by region, type of facility, and time of day are analyzed. As a result of analyzing the frequency of using the charger installed in Jeju Island, the utilization of both the fast charger and the slow charger is found to be concentrated in a specific area. The usage rate of charger installed in a business facility and a public parking lot is high in both fast charger and slow charger. However, according to the usage rate by time of day, the fast charger has a high utilization rate throughout the afternoon, while the use of a slow charger is concentrated in the morning. In order to enable users to utilize the electric vehicle charging station efficiently, it is necessary to provide a publicity guide for the charging station having a low utilization rate, a notice for using the charger, and a notification of completion of charging. Considering the charging demand, the area where the charger is not yet installed should be considered as the area to install the charger, and in addition, the additional installation should be considered in the area and the facility where the amount of charge is large. Service improvement is expected to be possible by utilizing actual electric vehicle charging behavior analysis result.