• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.755-758
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• 2007

For a stable water supply, it is necessary to consider the present unusual change in the weather, seasonal variation of water use, and the frequency and duration of low flow. Therefore, in this study, a theoretical background of specific probability distribution type and the reliability of frequency analysis for the time series of low flow data was investigated and programmed to support the operation of multipurpose dam.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.399-399
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• 2011

최근 한반도와 세계 곳곳에서 기후변화로 야기되는 이상기후에 의한 피해가 늘고 있으며, 그 피해 규모와 빈도 또한 점점 증가하는 추세이다. 이러한 추세 속에서 인적, 물적 피해를 최소화하기 위해 세계 각국이 기후변화에 대한 정확한 예측을 위한 많은 노력과 연구가 진행되고 있다. 지금까지 수행된 연구들은 일반적으로 강수특성의 변화를 파악하기 위해서 연 및 월 최대 강우량, 지속시간별 최대 강우량 등 총량적 개념을 이용한 연구가 대부분이다. 그러나 이는 실제 강수사상의 구조적 변화를 파악하는 데 있어서 한계가 있다. 본 연구에서는 전국 기상관측소 59개의 지점에 대한 1961년-2009년까지의 시계열 강수자료를 이용하여 지점 및 유역별 강수사상의 number of rain even, duration, intensity, quantity 시간분포 구조의 변화를 파악하고자 하였다. 분석결과 number of rain event와 total quantity는 전국적으로 증가 하였으며 total rain hour는 남해안 지역을 제외한 전국에서 증가 하는 것으로 분석 되었다. 결과를 바탕으로 강수변화의 패턴과 추세를 보다 정확하게 파악하고 미래강수 예측에 유용한 자료로 활용될 것으로 사료된다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42
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• pp.24-30
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• 2000

A system for evaluating streamflow data (KORSAS) was developed, and is operated using PC based Windows to help the hydrological observation practitioner's working in Korea Water Resources Corporation (KOWACO). This system has modules including; DB access and data management, flow measurement arranging, H-Q relation deriving, area rainfall calculating, flow calculating, and flow evaluating modules. Evaluation of observed streamflow is accomplished through the following processes. First, hourly streamflow data is calculated from water level data stored in a DB server by applying the rating relationship between water level and flow rates derived from the past flow measurements. Second, hourly areal rainfal data is calculated from point data stored in the DB server by applying Thiessen networks. Third, hydrographs are displayed on a daily, weekly, monthly, or seasonal duration basis, and are compared to hydrographs of reservoir inflow, hydrographs at water level observation stations and hydrographs derived from simulated results using models.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.65-71
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• 2000

A study was conducted to examine the relationship between abiotic factors and the population of white-fly (Dialeuropora decempuncta) in mulberry field. The study reveals that relationship between abiotic factors and the whitefly population is very much existent like other pests in other agricultural crops. Duration and time of distinct occurrence of whitefly in mulberry is influenced by the abiotic conditions of field. Abiotic parameters of previous month are more important in influencing the intensity of the pest than the current abiotic factors. Not all the abiotic factors are equally important but factors like minimum temperature, fluctuation in temperature during the days minimum relative humidity, fluctuation in relative humidity and rainfall are the major important lactors in influencing the intensity of the pest under consideration.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1124-1128
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• 2005

The duration of a construction project is not only a key element for taking a new order, but also a strict yardstick to determine certain project successful or not. However, since construction project is basically outdoor job and most of the activities are proceeded out-air, no matter how the schedule plan has been established accurately, actual project proceeds due to the weather condition, beyond anyone's control. In this paper, the functional relationship between work productivity rate and weather elements is suggested by regression analysis. Difference of the relationship and influence of weather due to the seasonal group are also revealed. With these results, by simulating actual weather data and generating weather forecast through historical data, more accurate schedule would be obtained.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4B
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• pp.413-427
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• 2010

Urbanization means the sudden increment of a population and the industrialization. The hydrologic water cycle causes many changes due to urbanization. Therefore, the affects that urbanization influences on the precipitation events were analyzed. But the precipitation events are very much influenced many meteorological and climatologically indices besides the effect of an urbanization. So, an analysis was performed by using precipitation data observed in many spots of the Korean peninsula. The analysis data are annual precipitation, the duration 1 daily maximum amount of precipitation, the rainy days, and 10 mm over the rainy days, and 80 mm. seasonal precipitation and seasonal rainy days. The analytical method classified 4 clusters in which the precipitation characteristic is similar through the cluster analysis. It compared and analyzed precipitation events of the urban and rural stations. Moreover, the representative rainfall stations were selected and the urban stations and rural stations were compared. In the analyzed result, the increment of the rainy days was conspicuous over 80mm in which it can cause the heavy rainfall. By using time precipitation data, the design precipitation was calculated. Rainfall events over probability precipitation on duration and return period were analyzed. The times in which it exceeds the probability precipitation in which the urban area is used for the hydrologic structure design in comparison with the rural area more was very much exposed to increase.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.81-92
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• 2013

This paper presents the results of a numerical investigation into the behavior of retaining wall subject to cycles of freezing and thawing due to seasonal temperature change. The thermo-hydro-mechanical coupled finite element modeling strategy was first established to simulate the wall behavior. A series of finite element analyses were then performed on a range of conditions representing seasonal temperature change characteristics. The results indicated that the average freezing temperature and the number of cycles of freezing and thawing were the primary influencing factors for the wall behavior. Also revealed was that the duration of freezing period does not significantly affect the wall displacement and the lateral earth pressure, and that the earth pressure on the wall does not significantly change due to the freezing and thawing action suggesting that the increase in the wall displacement during the freezing and thawing action may be attributed to degradation of backfill due to the freezing and thawing action.

• Journal of environmental and Sanitary engineering
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• v.23 no.4
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• pp.45-54
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• 2008

Our study indicates the zooplankton abundance with characteristics of water column and the vertical distribution in Lake Jinyang, South Korea. Seasonal changes of zooplankton community are determined by environmental parameters like water temperature, pH, dissolved oxygen, suspended solids and chlorophyll a. In lake Jinyang, this study showed that the zooplankton abundance in transition zone(St.1, St.2) was higher density than in lacustrine zone(St.3). Rotifers were dominant zooplankton and among them, Polyarthra spp., Keratella spp. and Nauplli(Copepoda) were common. But Cladoceran showed the low density. During survey period, zooplankton abundance with vertical distribution in surface layer(epilimnion) was higher than in bottom layer(hypolimninon). Zooplankton densities in Surface and middle layer showed positive relationship with water temperature and the densities in bottom layer(hypolimnion) showed positive relationship with chlorophyll a. Our assumption in spite of the short term study are supported by the facts that increase of temperature driven by climate change more maintains the thermocline duration by the summer temperature stratification. Thus the results suggest that the climate changes are an important source of changing zooplankton community feeding phytoplankton. So the zooplankton should be monitoring by the ecological management of Lake Jinyang to cope with climate changes like flood plain or drought.

• Journal of Korea Water Resources Association
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• v.47 no.3
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• pp.269-283
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• 2014

This study evaluated the environmental impact based on watershed characteristics and climate change using RCP climate change scenarios provided by the Korea Meteorological Administration. Future dam inflow was estimated by the SWAT model. Dam safety evaluation and downstream duration curve analysis was performed using HEC-ResSim model. Trends of water quality was analyzed through seasonal-Kendall Test using existing water quality observation data. Release discharge and tributary runoff derived SWAT and HEC-ResSim models applied to Qual2E and the future change in water quality trends were analyzed. Integrated environmental review watershed following techniques will be able to obtain the river environment management system and environmental issues such as climate change, new guidelines for preemptively response will be provided.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.27 no.4
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• pp.58-66
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• 2014

Objectives : The purpose of this study was to investigate the clinical manifestations and influences of occupation, concomitant allergic diseases, various aggravating factors and seasonal changes for patients with dyshidrotic eczema. Methods : A total of 219 patients who showed clinical manifestations of dyshidrotic eczema were included in this study. We retrospectively reviewed the clinical characteristics of all the patients. Results : 1. Among 219 patients, there were 76 male patients (34.7%), 143 female patients (65.3%), male to female ratio was 1: 1.88. The average age of the patients at admission was $31.9{\pm}9.8$ years, had a lot of 20s and 30s the distribution. 2. The average of duration of the admission to the clinic after the onset was $4.01{\pm}4.42$ years. 3. Common accompaning diseases dyshidrotic eczema patients have were allergic rhinitis(87 cases), and atopic dermatitis(55 cases), sweating(45 cases), and asthma(10 cases) in order. 4. The most commonly occurring sites for dyshidrotic eczema patients are fingers(60.3%), palm(53.4%), dorsum of hand(19.2%) and nails(5.5%) in order. 5. The most commonly contacted materials for dyshidrotic eczema patients are water(130 cases), cosmetics(40 cases) and rubber gloves(34 cases) in order. The aggravating factors of dyshidrotic eczema patients are emotional stress(110 cases), fatty food(22 cases) and alcohol(22 cases) in order. 6. The number of patients showing seasonal changes in symptoms was 111. The season with the most severe symptom was summer with 76 cases, which was statistically significant. Conclusions : This study demonstrated the various clinical characteristics of Korean patients with dyshidrotic eczema.