• 한국환경과학회지
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• 제2권2호
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• pp.103-113
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• 1993

The land and sea breeze over the Pusan coastal area is studied by three dimensional mesoscale numerical model. According to the results of the simulation experiments, both Pusan areas and Kimhae areas, the sea breeze began at 0800LST and the strongest at 1500LST and then at 1800LST. After midnight, the sea breeze changed about the land breeze and become weaker than that of the sea breeze in the daytime. Comparisons between calculations and observations showed that the characteristics of diurnal variation and v-component of the wind velocity relatively is similar to the Pusan areas. On the Kimhae areas, however, observations showed time lag which compared to the results of simulation experiments in the velocity of sea breeze and diurnal variation. From the above results, comparisons between calculations and observations is much more similar to the coastal areas than on the inland area.

• 한국환경과학회지
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• 제7권2호
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• pp.195-202
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• 1998

The low level atmospheric obsewation carried out to Investigate magnitude, formation and dissipation of nocturnal surface Inversion layer, also to survey relation to each meterological parameter In Inversion layer at Pusan power plant for Oct. 13, 1996. As coastal area, the surface Inversion layer height was relatively high(186m), and after sunset unstable layer formated firom surface to around 40m, and the Inversion layer was left still in the upper layer. The surface Inversion layer dissipated at 0920LST perfectly. The layer that strong Inversion layer was formated, showed steep variation of potential temperature and wand speed and relative humidity.

• 한국환경과학회지
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• 제8권5호
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• pp.555-558
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• 1999

A sea/land breeze circulation system and a regional scale circulation system are formed at a region which has complex terrain around coastal area and affect to the dispersion and advection of air pollutants. Therefore, it is important that atmospheric circulation model should be well designed for the simulation of regional dispersion of air pollutants. For this, Local Circulation Model, LCM which has an ability of high resolution is used. To verify the propriety of a LCM, we compared the simulation result of LCM with an exact solution of a linear theory over a simple topography. Since they presented almost the same value and pattern of a vertical velocity at the level of 1 km, we had a reliance of a LCM. For the prediction of dispersion and advection of air pollutants, the wind filed should be calculated with high accuracy. A numerical simulation using LCM will provide more accurate results over a complex terrain around coastal area.

• 한국통신학회논문지
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• 제28권8A호
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• pp.644-649
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• 2003

새로운 구조의 622Mbps급 버스트 모드 클럭/데이터 복원 회로를 구현하였다. 회로는 2개의 muxed oscillator (MO)와 위상 동기 회로 등으로 구성되어 있으며, passive optical network(PON) 시스템에 사용될 수 있도록 instantaneous locking 특성을 갖는다. 또한. 지터가 내재된 데이터가 인가되어도 데이터에 따라 클럭이 연동되어 항상 최적의 샘플링 포인트를 갖는다. 이 회로는 0.35$\mu\textrm{m}$ CMOS 공정을 이용하여 제작되었다. 측정 결과 제안된 클럭/데이터 복원 회로는 400Mbps 680MbPs 까지의 버스트 모드 입력 데이터를 에러없이 복원하였다.

• 한국치위생학회지
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• 제13권5호
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• pp.873-879
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• 2013

Objectives : The purpose of this study was to investigate the factors related to the dental fear based on the general characteristics, major and personality type of the 400 girl students in university in Ulsan. Methods : Subjects were 400 girl students in university in Ulsan from November 2012 to March 2013. Data were collected by questionnaire and dental checkup and analyzed using SPSS 20.0 version. Results : Neuroticism was closely related to dental clinic visit. Those who did not visit dental clinics tended to have low score of neuroticism. Conclusions : To reduce dental fear in girl students, it is necessary to make them visit dental clinics frequently and promote the preventive dental care effectively.

• 한국환경과학회지
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• 제15권3호
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• pp.203-209
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• 2006

In predicting oxidants concentration, the most important fact is to select a suitable photochemical reaction mechanism. Sensitivity analysis of $O_3$ and other important photochemical oxidants concentrations was conducted by using CBM-IV model. The predicted oxidants concentration was considerably related with the initial concentration of formaldehyde, $[NO_2]/[NO],\;NO_x$, RH and RCHO. As the initial concentration of formaldehyde increased, concentration of $NO_2$ increased. $O_3$ concentration was proportional to the $[NO_2]/[NO]$ ratio. When the initial concentrations of RH and RCHO were high, photochemical reaction was more reactive, including more rapid conversion of NO to $NO_2$ and increased oxidants. Also, the sensitivities of ozone formation to rate constants, $K_l,\;K_2\;and\;K_3$ in the $NO_2$ photolysis were studied.

• 한국환경과학회지
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• 제10권6호
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• pp.407-415
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• 2001

A case of air pollution study of estimation of emission rate for source to railroad rolling stock and emissive character about is unusual. Recent emission rate of railroad rolling stock was estimated with emission factor of EPA in three region(Seoul, Incheon, and Gyeonggido). But this EPA factor could be incorrect because Korea and America have a different railroad environment in the variety of fuel and character of railroad rolling stock In this study, emission rate of each line, car and region(district) with omission factor of Korean case(National Railroad Administration, 1997) was estimated. In Busan Metropolitan City, railroad rolling stocks were divided accoding to, each line, car and service. Particularly, the Idle fuel rate omitted in the preceding study was included in calculation fuel rate. Total emission rate of Busan Metropolitan City was 887.41 t/year Each emission rates of Kyeongbu line, Donghaenambu line, Gaya line, Uam line, Bujeon line, and idle was 489.15t, 196.46t, 33.94t, 12.66t, 6.47t, and 48.75t, respectively.

• 한국환경과학회지
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• 제23권11호
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• pp.1929-1941
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• 2014

Now a days, frequency of abnormally high temperatures like heat wave by global warming and climate change is increasing constantly and the number of patient with heat related illness are jumping rapidly. In this study, we chose the case day for the heat wave in Busan area(Busan and Yangsan), 2013 which it was the most hottest year during 21th century. And then, we analysed the weather condition using automatic synoptic observing system(ASOS) data. Also, four indices, heat index(HI), wet bulb globe temperature(WBGT), Man-ENvironment heat EXchange model(MENEX)'s results like Physiological subjective temperature(PST), Physiological strain(PhS), were calculated to evaluate the thermal comfort and stress quantitatively. However, thermal comfort was different as the each station and thermal comfort index during same time. Busan's thermal indices (HI: hot, WBGT: sweltering, PST: very hot, PhS: very hot) indicated relatively higher than Yansan's (HI: very hot, WBGT: sweltering, PST: very hot, PhS: sweltering). It shows that Busan near coast is relatively more comfortable than Yangsan located in inland.

• 한국환경과학회지
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• 제23권11호
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• pp.1807-1820
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• 2014

The spatial and temporal changes of the annual mean urban heat island(UHI) intensity were investigated using near surface temperature data measured at 16 automatic weather systems(AWS) in Busan metropolitan area(BMA) during the 11-yr period, from 2000 to 2010. For nighttime, the annual mean UHI intensity at Dongnae(U1) in 2000 was weaker than it in 2010. However the change of the annual mean UHI intensity at Daeyeon(U2) during 11 years was different from it at U1. The annual frequency of the UHI intensity over $5^{\circ}C$ considerably increased at U2 and decreased at U1 during 11 years. The center of the UHI also spatially shifted southward with Daeyeon and Haeundae in BMA. It would be caused by the increase of urban area, population-density and transportation near U2 and by the decrease of them near U1. We found that the spatial and temporal differences of the UHI intensity have coincided with changes of land-use, population density and transportation in BMA.

• 한국대기환경학회지
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• 제28권3호
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• pp.261-272
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• 2012

In this study, climate variability was predicted by the Weather Research and Forecasting (WRF) model under two different scenarios (current trends scenario; SC1 and managed scenario; SC2) for future urban growth over the Seoul metropolitan area (SMA). We used the urban growth model, SLEUTH (Slope, Land-use, Excluded, Urban, Transportation, Hill-Shade) to predict the future urban growth in SMA. As a result, the difference of urban ratio between two scenarios was the maximum up to 2.2% during 50 years (2000~2050). Also, the results of SLEUTH like this were adjusted in the Weather Research and Forecasting (WRF) model to analysis the difference of the future climate for the future urbanization effect. By scenarios of urban growth, we knew that the significant differences of surface temperature with a maximum of about 4 K and PBL height with a maximum of about 200 m appeared locally in newly urbanized area. However, wind speeds are not sensitive for the future urban growth in SMA. These results show that we need to consider the future land-use changes or future urban extension in the study for the prediction of future climate changes.