• 제목/요약/키워드: Wind-pressure

검색결과 1,472건 처리시간 0.032초

The Development of the Anchor Dragging Risk Assessment Program (선박 주묘 위험성 판별 프로그램 개발에 관한 연구)

  • Kim, Joo-Sung;Park, Jun-Mo;Jung, Chang-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • 제24권6호
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    • pp.646-653
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    • 2018
  • Marine accidents caused by dragging anchors occur constantly due to enlargement of ships' size and unusual weather conditions. Nevertheless, vessel operators rely on their experience because the calculations of actual holding power and external forces are complex and inconvenient. The purpose of this study was to propose a program for the anchor dragging risk assessment in order to provide crew and VTSO with the information to determine easily the danger of dragging and take appropriate action. The input data in this program were composed of the ship's basic particulars, anchoring condition, and external environment etc. on calculating for the wind pressure, frictional force, drift force, and holding power. Three dragging anchor accidents were applied to the program's data input at the time of the day, then the result was assessed by 'warning', which was verified with a high confidence. As a result, the risk of dragging anchors can be predicted in advance through this program. In further studies, it is necessary to simplify the input data and improve user convenience through automatic input from various equipment.

A clinical study on facial paralysis. (口眼와斜에 대한 臨床的 考察)

  • An, Su-Gi;Hwang, Choong-Yeon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • 제4권1호
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    • pp.89-98
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    • 1991
  • Clinical study on the 114 facial paralysis patients, visited Won Kwang University Oriental Medical Hospital in Kwang ju from July 1990 to Jun 1991, was carried out. The results obtained are as follows. 1. Prevalence was almost same in both sexes and high in the age of 3 and 4 decades but distributed in an age group. 2. Majority of the patients were nomotensive, which meant blood pressure did not affect the incidence. 3. The incidence distributed in every occupations but high in housewife as 37 cases ($32\%$) and decreased gradually in office employee, labor worker, student and merchant in order. 4. Overwork, wind and cold, emotional stress, and numerous implicated agents were etiological factor. 5. The paralysis mostly occured in summer and winter as 40($35\%$) and 37 cases($32\%$) respectively, 18($16\%$) and 19cases($17\%$) were recorded respectively in spring and autumn. 6. The majority of patients showed only facial muscle paralysis without other complications, whose cure rate was $60\%$ (47 cases). The patients with auditory impairment or taste loss was less common and cure rate was low. 7. The number of the patients with migraine or mastoid pain was 81($71\%$), which was more than 33 patients($29\%$) with such pain. The cure rate was high in the patients without migraine than with migraine as a raito of 64 to $46\%$. 8. Most of duration from attack to admission were in a week as 86 cases($75\%$) and the patients with duration over 4 weeks 11 cases($10\%$). The cure rate of the patients in a week, was 54 cases($60\%$) and the patients over 4 weeks was none($0\%$), which meant shorter the duration was, the beter the result was. 9. Response on electro acupuncture on initiating therapy showed good in 39 cases($34\%$) the majority group, moderate in 37 cases, exellent in 29 cases and poor in 5 cases. 10. The results of treatment were as follows : asymptomatic in 58 cases($51\%$), improved n 40cases($35\%$), effective in 10 cases($9\%$) and ineffective in 6 cases($5\%$). 11. Cure rate according to the response on electro acupuncture showed $72\%$ in exellent group, $59\%$ in good group, $27\%$ in moderate groop, and $0\%$ in poor group. These show the better the response on the electro-acupuncture is, the higher the cure rate is, which will be able to indicate the prognosis of facial paralysis.

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Regional Realtime Ocean Tide and Storm-surge Simulation for the South China Sea (남중국해 지역 실시간 해양 조석 및 폭풍해일 시뮬레이션)

  • Kim, Kyeong Ok;Choi, Byung Ho;Lee, Han Soo;Yuk, Jin-Hee
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • 제30권2호
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    • pp.69-83
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    • 2018
  • The South China Sea (SCS) is a typical marginal sea characterized with the deep basin, shelf break, shallow shelf, many straits, and complex bathymetry. This study investigated the tidal characteristics and propagation, and reproduced typhoon-induced storm surge in this region using the regional real-time tide-surge model, which was based on the unstructured grid, resolving in detail the region of interest and forced by tide at the open boundary and by wind and air pressure at the surface. Typhoon Haiyan, which occurred in 2013 and caused great damage in the Philippines, was chosen as a case study to simulate typhoon's impact. Amplitudes and phases of four major constituents were reproduced reasonably in general, and the tidal distributions of four constituents were similar to the previous studies. The modelled tide seemed to be within the acceptable levels, considering it was difficult to reproduce the tide in this region based on the previous studies. The free oscillation experiment results described well the feature of tide that the diurnal tide is prevailing in the SCS. The tidal residual current and total energy dissipation were discussed to understand the tidal and sedimentary environments. The storm-surge caused by typhoon Haiyan was reasonably simulated using this modeling system. This study established the regional real-time barotropic tide/water level prediction system for the South China Sea including the seas around the Philippines through the validation of the model and the understanding of tidal characteristics.

Estimation of Air-Sea Heat Exchange Using BUOY Data at the Yellow Sea, Korea (부이 관측자료를 이용한 서해 해역의 해양-대기 열교환량 산출)

  • kang, Yune-Jeung;Hwang, Seung-On;Kim, Tae-Hee;Nam, Jae-Cheol
    • Journal of the Korean earth science society
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    • 제22권1호
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    • pp.40-46
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    • 2001
  • Heat exchange between the atmosphere and sea is produced using the data from two 3m discus buoy installed by KMA in 1996. The meteorological and oceanic characteristics at the Dukjukdo and Chilbaldo buoy for the period 1996 ${\sim}$ 2000 are discussed. Daily averaged sensible heat and latent heat flux at each site are estimated from bulk aerodynamic method using given data and analyzed. Quantitative analyses show SST indicates 1-year cycle like air temperature but has 1 month lag. Sea level pressure is lowest in July, humidity is higher from May to August, and wind speed has averaged value of 5 m/s and higher in autumn and winter. Sensible heat flux analyses present that strong heat loss from the sea occurs in autumn and winter and weak heat loss from atmosphere appears in spring and summer, and net sensible heat loss from the sea is found throughout the year. The ocean significantly releases latent heat into atmosphere from August to May but get a little latent heat from atmosphere in other months. Net latent heat loss from the sea is larger than net sensible heat loss except in January and February. Comparison with two sites suggests that the magnitude of heat flux and their fluctuation are generally stronger at Dukjukdo than at Chilbaldo. In case study, both sensible and latent heat flux is a little more at Chilbaldo in March 1998, but substantially stronger at Dukjukdo in November 1996.

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Influence of Land Use and Meteorological Factors for Evapotranspiration Estimation in the Coastal Urban Area (해안도시 지역에서 증발산량 산정에 토지이용도와 기상인자의 영향성)

  • Yang, Sung-Il;Kang, Dong-Hwan;Kwon, Byung-Hyuk;Kim, Byung-Woo
    • Journal of Environmental Science International
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    • 제19권3호
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    • pp.295-304
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    • 2010
  • Actual evapotranspiration (AET) in the Suyeong-gu was estimated and correlations between AET and meteorological factors were analyzed. The study area was Suyeong-gu lay at the east longitude $129^{\circ}$ 05' 40" ~ 129$^{\circ}$ 08' 08" and north latitude $35^{\circ}$ 07' 59" ~ $35^{\circ}$ 11' 01". The Kumryun mountain, the Bae mountain, the Suyeong river and the Suyeong bay are located on west, north, northeaster and south side in the study area, respectively. AET was estimated using precipitation (P), potential evapotranspiration (PET) and plant-available water coefficient. Meteorological factors to estimate PET were air temperature, dewpoint temperature, atmospheric pressure, duration of sunshine and mean wind speed (MWS). PET and AET were estimated by a method of Allen et al. (1998) and Zhang et al. (2001), respectively. PET was the highest value (564.45 mm/yr) in 2002 year, while it was the lowest value (449.95 mm/yr) in 2003 year. AET was estimated highest value (554.14 mm/yr) in 2002 year and lowest value (427.91 mm/yr) in 2003 year. Variations of PET and AET were similar. The linear regression function of AET as PET using monthly data was AET=0.87$\times$PET+3.52 and coefficient of determination was high, 0.75. In order to analyze relationship between the evapotranspiration and meteorological factors, correlation analysis using monthly data were accomplished. Correlation coefficient of AET-PET was 0.96 high, but they of AET-P and PET-P were very low. Correlation coefficients of AET-MWS and PET-MWS were 0.67 and 0.73, respectively. Thus, correlation between evapotranspiration and MWS was the highest among meteorological factors in Suyong-gu. This means that meteorological factor to powerfully effect for the variation of evapotranspiration was MWS. The linear regression function of AET as MWS was AET=84.73$\times$MWS+223.05 and coefficient of determination was 0.54. The linear regression function of PET as MWS was PET=83.83$\times$MWS+203.62 and coefficient of determination was 0.45.

Estimation of Erosion Damage of Armor Units of Rubble Mound Breakwaters Attacked by Typhoons (태풍에 의한 경사식 방파제의 피복재 침식 피해 산정)

  • Kim, Seung-Woo;Suh, Kyung-Duck
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • 제22권5호
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    • pp.295-305
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    • 2010
  • Although the rubble mound breakwaters in Korea have been damaged by typhoons almost every year, quantification of erosion of armor block have seldomly been made. In this paper, the damage of armor units is standardized by the relative damage. In the case where the number of damaged units is reported, it is divided by the total number of units to calculate the relative damage. In the case where the rehabilitation cost is reported, the relative damage is calculated by using its relationship with the present value of the past rehabilitation cost. The relative damage is shown to have strong correlations with the typhoon parameters such as nearest central air pressure and maximum wind speed at each site. On the other hand, the existing numerical methods for calculating the cumulative damage are compared with hydraulic model tests. The method of Melby and Kobayashi (1998) is shown to give a reasonable result, and it is used to calculate the relative damage, which is compared with the measured damage. A good agreement is shown for the East Breakwater of Yeosu Harbor, while poor agreement is shown for other breakwaters. The poor agreement may be because waves of larger height than the design height occurred due to strong typhoons associated with climate change so that the relative damage increased during the last several decades.

The Study on the Sweating Responses of Adult Female according to Garment types (의복형태에 따른 성인여성의 발한반응에 관한 연구)

  • Yeom Hee Gyong;Choi Jeong Wha
    • Journal of the Korean Society of Clothing and Textiles
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    • 제16권4호
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    • pp.405-416
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    • 1992
  • This study was performed to investigate correlation between total body weight loss and local sweat rate and to find out any possible method that can estimate total body weight loss judging from local sweat rate. Twelve adult females were kept at 44 $\pm1^{\circ}C$, 50 ${\pm}5\%$ R.H. (1) Physiological responses such as total body weight loss, local sweat rate, rectal temperature, skin temperature, blood pressure and pulse, (2) micro climate inside garment and (3) subjective sensation were examined. Two types of garment such as long-sleeves with long pants (Type I) and half·sleeves with short pants (Type II) were used to observe the effect of garment types on sweating response. Both clothing weight was equal (132$\pm$3 g/$m^{2}$). The results were as follows: 1. Regardless of the different types, total body weight loss was more interrelated with the sweat rate on forehead than any other parts of the body. Except the forehead, different parts of body with different types of garment influenced on body weight loss quite differently. 2. Total body weight loss was more interrelated with the weight gain of garment than the local sweat rate. 3. Under the environment of 44$\pm1^{\circ}C,\;50{\pm}5\%$R.H., body weight loss during 1 hour of subject clothed and silted was 275.2 g/hr and weight loss per body surface area was 178.9 g/$m^{2}/hr$ Garment types have no influences on total body weight loss. 4. Local sweat rate (mg/7.07 $cm^{2}/hr$) was 208.0,191.0, 133.0, 115.0,81 0, 75.1 and 66.3 on scruff, breast, forehead, forearm, thigh, upper arm, leg respectively No evidence has been found that garment types influenced on local sweat rate (p<0.1). 5. No interrelationships between rectal temperature and total body weight loss, local skin temperature and total body weight loss, and local skin temperature and local sweat rate were found. From this study, some possible method that we can estimate total body' weight loss judging from weight loss of garment. But considering the fact that clothing design factor, the physical characteristics of fabric and environmental factor such as humidity and wind velocity should be concerned in weight loss of garment, it should be studied further whether the total body weight loss can be estimated properly from the weight loss of garment. This experiment suggest that different parts of body with different types of garment can influence on body weight loss quite differently. Therefore, in order to get more precise results, more studies under the diversity of garment types should be done in the near future.

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The Characteristics of Earth System Thinking of Science Gifted Students in relation to Climate Changes (기후변화와 관련된 과학영재들의 지구시스템 사고 특성)

  • Park, Kyeong-Jin;Chung, Duk-Ho
    • Journal of Gifted/Talented Education
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    • 제24권2호
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    • pp.271-288
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    • 2014
  • This study aimed to investigate the perception of earth system thinking of science gifted students in future problem solving (FPS) in relation to climate changes. In order to this study, the research problem associated with climate changes was developed through a literature review. The thirty seven science gifted students participated in lessons. The ideas in problem solving process of science gifted students were analyzed using the semantic network analysis method. The results are as follows. In the problem solving processes, science gifted students are 'changes of the sunlight by water layer', 'changes of the Earth's temperature', 'changes of the air pressure', ' change of the wind and weather' were represented in order. On other hand, regard to earth system thinking for climate changes, while science gifted students were used sub components related to atmospheres frequently, they were used sub components related to biosphere, geosphere, and hydrosphere a little. But, the analytical results of the structural relationship between the sub components related to earth system, they were recognised that biosphere, geosphere, and hydrosphere used very important in network structures. In conclusion, science gifted students were understood well that components of the earth system are influencing each other.

The Methodology for Prediction and Control of Hazardous Chlorine Gas Flow Releases as Meteorological Data (기상조건에 따른 유해독성염소가스의 가상흐름누출에 관한 예측 및 제어론)

  • Kim, Jong-Shik;Park, Jong-Kyu
    • Applied Chemistry for Engineering
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    • 제10권8호
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    • pp.1155-1160
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    • 1999
  • The screening methodology modeling, dispersion modeling procedures for continuous and instantaneous releases of the gas phase flow from the storage tank and pressure relief valve were considered. This study was performed to develop the screening methodology for prediction and control of hazardous/toxic gas releases by estimating the 1-hr average maximum ground-level concentration of $Cl_2$ gas vs. downwind distance by incorporating source term model including the general/physical properties of released material and release mode of the $Cl_2$ storage tank of the chemical plant facilities, dispersion model, and meteorological/topographical data into the TSCREEN model. As the results of the study, it was found that dispersion modes of the dense gas were affected by the state of the released material, the released conditions, physical-chemical properties of released material, and the released modes (continuous and instantaneous releases), and especially largely affected by initial (depressurized) density of the released material and release emission rate as well as the wind velocity. Especially, this study was considered to release hazardous material as meteorological data. It was thought that this screening methodology can be useful as a preliminary guideline for application of the refined analysis model by developing the generic sliding scale methodology for various senarios selected.

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Numerical Simulation of Storm Surge and Wave due to Typhoon Bolaven of 2012 (2012년 태풍 볼라벤에 대한 폭풍해일과 파랑 수치모의)

  • Kim, Gun Hyeong;Ryu, Kyong Ho;Yoon, Sung Bum
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • 제32권4호
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    • pp.273-283
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    • 2020
  • Numerical simulations of the storm surge and waves induced by the Typhoon Bolaven incident on the west sea of Korea in 2012 are performed using the JMA-MSM weather field provided by the Japan Meteorological Agency, and the calculated surge heights are compared with the time history observed at harbours along the various coasts of Korea. For the waves occurring coincidentally with the storm surges the calculated significant wave heights are compared with the data measured using the wave buoys operated by the Korea Hydrographic and Oceanographic Agency and the Korea Meteorological Administration. Additional simulations are also performed based on the pressure and wind fields obtained using the best track information provided by the Joint Typhoon Warning Center, and the calculated results are compared and analyzed. The waves and storm surges calculated using JMA-MSM wether field agree well with the observations because of the better reflection of the topography and the pre-background weather field. On the other hand, the calculated results based on the weather fields produced using the JTWC best track information show some limitations of the general trend of the variations of wave and surge heights. Based on the results of this study it is found that the reliable weather fields are essential for the accurate simulation of storm surges and waves.