• Journal of Environmental Science International
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• v.16 no.5
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• pp.593-602
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• 2007

The frequency of tropical nights and tropical days in Busan during summer season (June-August) from 1995 to 2004 were investigated. When air temperature higher than $25^{\circ}C$ continuously maintains at night in summer, it is called the occurrence of tropical night. Tropical day is defined that maximum air temperature is higher than $30^{\circ}C$, In Jin-Gu and Daeyeon-dong shows a lot of frequency of tropical day and tropical night because there were located in downtown. Relatively, the areas where are located in seaside and riverside show very low frequency. This can be explained the cooling effects of sea and river. The main meteorological characteristics during tropical nights and tropical days is proved pattern of reverse tendency through wind rose. We analyzed heat index and discomfort index during tropical night and tropical day. This study is useful to understand the aspect of urban thermal environment but need some more observation to quantify.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.873-885
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• 2014

To identify the characteristics of extreme heat events and tropical nights in major cities, the correlations between automated synoptic observing station (ASOS), automatic weather station (AWS), and temperature in seven metropolitan areas were analyzed. Temperatures at ASOS were found to be useful sources of the reference temperature of each area. To set the standard for identifying dates of extreme heat events in relation to regional topography and the natural environment, the monthly and yearly frequency of extreme heat in each region was examined, based on the standards for extreme heat day (EHD), tropical night day (TND), and extreme heat and tropical night day (ETD). All three cases identified 1994 as the year with the most frequent heat waves. The frequency was low according to all three cases in 1993, 2003 and 2009. Meanwhile, the yearly rate of increase was the highest in 1994, followed by 2010 and 2004, indicating that the frequency of extreme heat changed significantly between 1993 and 1994, 2003 and 2004, and 2009 and 2010. Therefore all three indexes can be used as a standard for high temperature events. According to monthly frequency data for EHD, TND, and ETD, July and August accounted for 80% or more of the extreme heat of the entire year.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5B
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• pp.397-408
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• 2009

In this study, a stochastic precipitation generation framework for simultaneous simulation of daily precipitation at multiple sites is presented. The precipitation occurrence at individual sites is generated using hybrid-order Markov chain model which allows higher-order dependence for dry sequences. The precipitation amounts are reproduced using Anscombe residuals and gamma distributions. Multisite spatial correlations in the precipitation occurrence and amount series are represented with spatially correlated random numbers. The proposed model is applied for a network of 17 locations in the middle of Korean peninsular. Evaluation statistics are reported by generating 50 realizations of the precipitation of length equal to the observed record. The analysis of results show that the model reproduces wet day number, wet and dry day spell, and mean and standard deviation of wet day amount fairly well. However, mean values of 50 realizations of generated precipitation series yield around 23% Root Mean Square Errors (RMSE) of the average value of observed maximum numbers of consecutive wet and dry days and 17% RMSE of the average value of observed annual maximum precipitations for return periods of 100 and 200 years. The provided model also reproduces spatial correlations in observed precipitation occurrence and amount series accurately.

• The Journal of Korean Physical Therapy
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• v.17 no.2
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• pp.22-37
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• 2005

This study was performed to investigate LBP(low-back pain) prevalence rate and its related factors inphysical therapists. A self-administered questionnaire survey was conducted to 522 physical therapists in Daegu and Gyeongsangbuk. The LBP prevalence rate for recent 6 months was $61.7\%$. According to age, the prevalence rate was highest in the group aged 24 or less for both male and female physical therapistis. For male physical therapists , it was higher in smokers and drivers, but for female ones, it was not in a significant relationship with smoking and driving. According to work experience, the prevalence rates of those who had been working for less than one year were the highest, and those who had been working at hospitals and clinics were $69.1\%$, significantly high. According to therapy techinque, the prevalence rate related ti PNF was $71.6\%$, the highest and to occupational therapy was $34.3\%$, the lowest. According to working environment for six months, in both male and female physical therapists. LBP prevalence rate was in a statistically significant relationship with work hours during the day, night and weekend duties, repetitive works, motions that bend or twist the waist, the number of patients per day, the number of time to help patients per day, the number of time to carry medical equipment per day and the length of time to work standing. The rate was also higher when physical therapists fekt nire stress from their work. According to the result of multiple logistic regression analysis, male was in a significant relationship with work experience and motions that bend or twist the waist and female was in a significant relationship with work hours during the night and weekend duties, the number of time to help patients per day, motions that bena or twist the waist, actions taken to protect the waist. As for the developmental pattem of LBP in the group of physical therapists with LBP for six moths, $15.7\%$ of them had LBP for first time, $42.3\%$ had recurred LBP, and $42.0\%$ had chronic LBP. As for the causes of LBP, $51.7\%$ said that it was because they worked in the same posture for a long time, and as for how to treat LBP, 48.8% said that they treated themselvs or got help from their co-wokers. The results presented above suggest that physical therapists are exposed to high risk of LBP caused form occupational activities. Therefire, it is necessary to improve working environment to reduce the occurrence of LBP and to develop education programs for preventing the occurrence and recurrence of LBP.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.26-35
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• 1993

Differences in weed occurrence was investigated among five types of rice (Oryza sativa L.) cultivation. The five types employed were three transplanting cultivations such as conventional hand transplanting, machine transplanting with 30-day-old seedling, and machine transplanting with 10-day-old seedling and two direct-seedings such as flood direct-seeded rice by pregerminated seed and dry direct-seeded rice by dry seed. Weed specie, occurred varied from 7 to 20, depending on the different cultivation types. Weeds were more diverse in transplanting with l0-day-old seedling than in other transplanting cultivations and in direct-seeding than in transplanting practice. Dominant weed species also varied with cultivation types. In transplanting cultivations Scirpus juncoides Roxb., Echinochloa crus-galli (L.) P. Beauv., and Eleocharis kuroguwai Ohwi were dominant, whereas occurrence of annual weeds such as Cyperus difformis L. and Monochoria vaginalis Presl. aside from the three weed species increased in direct-seeded cultivations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4D
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• pp.513-521
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• 2008

The objective of this study is the evaluation of the impact on the construction condition due to historical observation data and IPCC SRES A2 climate change scenario. For this purpose, daily precipitation and daily mean temperature data which have been observed over the past 30 years by Korea Meteorological Administration are collected and applied. Also, A2 scenarios during 2011~2040 and 2051~2080 are used for this analysis. According to the results of trend analyses on annual precipitation and annual mean temperature, they are on the increase mostly. The available working day and the day occurred an extreme event are used as correlation indices between climate factor and construction condition. For the past observation data, linear regression and Mann-Kendall test are used to analyze the trend on the correlation index. As a result, both working day and extreme event occurrence day are increased. Likewise, for the future, variation analysis showed the similar result to that of the past and the occurrence frequency of extreme events is increased obviously. Therefore, we can project to increase flood damage potential on the construction site by climate change.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.45-60
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• 2009

Occurrence ecology and possibility of mass trapping of Popillia quadriguttata, one of the most serious turfgrass insect pest in domestic golf courses was investigated using pheromone traps in Gimpo and Jinhae. Peak period of adult occurrence of P. quadriguttata was late June and early July in Gimpo Seaside Country Club from 2006 to 2008. It was early and middle July in Youngwon Country Club in 2006. The first catched day of P. quadriguttata adult was 20 June, while the last day was 10 September in Gimpo Seaside Country Club, 2006. Mean catched number of P. quadriguttata adult in Japanese beetle pheromone trap per day in peak period of occurrence were 18.2, 25.7, 29.0, and 15.7 at 2005, 2006, 2007 and 2008 respectively. Mean catched number of P. quadriguttata adult in Japanese beetle pheromone trap were more in fairways or roughs than tees or greens. Possibility of control of scarab beetle using pheromone trap with pesticide treatment was investigated against oriental beetle, Blitopertha orientalis in Dongrae Benest Golf Club. Mean number of dead oriental beetle adult were more higher(2.9 folds) in fenitrothion EC treatment than fenitrothion EC treatment after set oriental beetle pheromone trap.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.2
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• pp.105-116
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• 2023

The fatality rate of secondary accidents is seven times that of general traffic accidents. If limited to highways, one in four deaths are said to occur from secondary accidents. Unexpected situations which do not give drivers time to prepare are the cause of secondary accidents. This risk results in more fatalities on highways with high driving speeds. Existing studies have conducted research on traffic accidents and on secondary traffic accidents that occur after a primary traffic accident, without considering unexpected situations that may occur on the road. Therefore, to reduce damage and casualties caused by secondary accidents, there is a need to create a safe road environment by removing the possibility of causing accidents. This study analyzes whether the day of occurrence, time of occurrence, and radius of the curve of an unexpected situation are related to the occurrence of an unexpected situation. This study was based on data of accidents that occurred in 2022 on the Cheonan-Nonsan Expressway and the Seoul-Yangyang Expressway. The radius of the curve was calculated by dividing the section of the highway into straight, clothoid, and curved sections through cluster analysis. Results of the analysis indicate that the day and time of occurrence and the curve radius are associated with unexpected situations.

• Journal of the Korean Geographical Society
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• v.46 no.1
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• pp.36-49
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• 2011

This paper aims to investigate the frequency and intensity variations of Okhotsk high pressure system focused on the Korean Peninsula. Weather chart (00UTC), daily weather data and reanalysis data were used. The first occurrence date of Okhotsk high pressure system tends to be earlier in those years that surrounding land air temperature in April is high. The frequency of Okhotsk high has recently decreased, and its intensity tends to be stronger when the difference between sea surface temperature and surrounding land air temperature is big. The frequency of Okhotsk high in April, May, June and July increases when surrounding land air temperature is high, and its intensity grows when the difference between surrounding land air temperature and sea surface temperature is big. The frequency of Okhotsk high may increase and its intensity may increase when the first occurrence date comes earlier. In June, however, the reverse may apply.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.367-374
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• 2015

The aim of this study was to assess the occurrence and foraging of social and other wasps and bees in Jirisan National Park (JNP, South Korea), in particular in an apiary. Sixty one traps were placed in the southwestern part of JNP to identify social wasps from July to September 2014, and the damage to the apiary caused by wasps or bees was observed once a month from May to December 2014 between 10 a.m. and 5 p.m. In total, 10 species of Vespidae were collected by trapping. Vespa crabro was the most abundant (245 individuals, 28.3%), followed by Vespa velutina (162 individuals, 18.7%). In the apiary, however, V. velutina was the most frequent species. V. velutina visited a maximum of 167 times a day in September, which corresponded to one visit in 2.5 min. Accordingly, these data are in line with the most serious impact of V. velutina on the apiaries in South Korea. V. simillima was the second most frequent species; both Vespa species hawked honeybees. Even though the occurrence of V. mandarinia was low, this species caused serious damage by mass slaughter of honeybees. The occurrence of V. crabro, V. analis and V. ducalis was quite low and their impact on honeybees was negligible. There have been few reports of V. dybowskii foraging for honeybees, but they are considered to be a new pest because their impact on apiaries is considerable. Most Vespa species attacked the apiary from June to October, with a maximum in September. However, V. velutina visited until November to early December. Vespula species are not more serious pests than Vespa species, but many adults were observed stealing honey from beehives. Polistes, Orancistrocerus, and Bombus species had no impact on honeybee colonies in the apiary.