The purpose of this study is to extract climate element affecting coffee yield by growth period using data of production and cultivation area of coffee and climate data for 2000-2018. During the analysis period, the production of coffee in Vietnam has been consistently increasing, but Ðăk Lăk in the Central Highlands, the main cultivation area for coffee production, has recently stagnated in the trend of increasing yield. The yield of Lâm Đồng, located in the relatively highlands of the Central Highlands, is steadily increasing. Coffee yields of Ðăk Lăk is negatively correlated with the temperature during flowering period, and is also significantly negatively correlated with the maximum temperature and precipitation during the late growing period. On the other hand, Lâm Đồng, located at a relatively high altitude, has a positive correlation with temperature during the late growing period. It is analyzed that the lower the altitude, the higher the temperature, the lower the coffee productivity due to the high temperature appearance, and the lower the low temperature appearance in the high altitude region.

이 연구에서는 전단연결재의 종류를 변수로 더블리브유닛 깊은 데크플레이트 슬래브의 휨 실험을 수행하였으며, 실험결과를 기반으로 비선형유한요소해석을 통하여 춤이 깊은 데크플레이트와 콘크리트 사이의 합성도를 평가하였다. 그 결과, 전단 연결재가 설치되어 있는 경우 휨 강성 및 강도가 크게 향상되는 것으로 나타났다.

The purpose of this study is to examine the effect of climatic elements on the arabica coffee yield during the various growth stages of coffee plant for the period of 1996-2017 over Costa Rica. For the future scenario, change rate of arabica coffee yield is also estimated using the data of production and cultivated area. The cultivation area and the yield of arabica coffee has been decreasing since the 1990s in Costa Rica. The decreasing trend in arabica coffee yield could have a negative effect on Costa Rica’s coffee industry in the future. During the dry season, the yield of arabica coffee has significant negative correlation with precipitation at the stage of flowering in the month of February. In case of wet season, coffee yield and temperature were negatively correlated while precipitation showed positive association with coffee yield at the stage of growing period in the month of August. However, the observation revealed the excessive precipitation drastically reduced arabica coffee yield in 2013 during August, the month of wet season. According to the RCP 4.5 and RCP 8.5 climate change scenarios, due to high temperature and fluctuated precipitation the yield of arabica coffee is unstable and the future of coffee industries is also insecure.

In this study, a numerical research has been conducted to investigate the fire resistance performance of prestressed hollow-core slabs, in which the number of prestressing strands and the load ratio were set as the analysis parameters. Based on the numerical simulation results, the temperature distribution and deflection according to the fire duration time were analyzed in detail.

In this study, an experimental research was conducted to investigate the effective compressive strengths of slab-column connections with different strengths. From the test results, it was found that the effective compressive strengths of the interior columns completely restrained by slab were similar to the compressive strengths of the columns.

The purpose of this study is to extract climate factors affecting sweet persimmon yield by growth period and estimate the rate of future sweet persimmon yield using data of production and cultivation area of sweet persimmon and climate data for 1998-2015. During the analysis period, the cultivation area of sweet persimmon in Gyeongnam has been consistently decreasing, but sweet persimmon yield has increased. Climate factors that have statistically significant effects on sweet persimmon yield are mean temperature, maximum temperature, precipitation, precipitation days, and sunshine hours. The sweet persimmon yield is a statistically positively correlated with temperature and sunshine hours and negatively correlated with precipitation during the flowering period (April to May). The sweet persimmon yield is statistically positively correlated with precipitation in the growing period (June to August) and negatively correlated with temperature in maturity period (September to November). Future sweet persimmon yield is estimated to have a steadily decreasing rate of change in future climate change scenarios, RCP4.5 and RCP8.5.

In this study, spatio-temporal distribution was analyzed with the number of days for summer heat wave and winter cold wave defined as three or more consecutive +5% quantile days and -5% quantile days, respectively, by using daily maximum temperature in summer and daily minimum temperature in winter during 1973-2015. Although monthly heat wave occurrence has been only concentrated in July and August during the 1970s and 1980s, it had further extended into June and September since the 2000s. Monthly cold spell occurrence has been distinguished by increasing occurrence ratio in the month of December since the 2000s. The occurrences of heat waves were classified into either strong or weak cluster depending on intensity and magnitude over the entire region of South Korea rather than in specific areas. On the other hand, the occurrences of cold spell were classified by intensity of cold spell and spatial distribution of dominant cold spell areas over South Korea.

In this study, we analyzed the effect of the drainage slope to collapse. The presence of drainage has a low correlation with the collapse of the slope. But drainage of the drainage has an important role in preventing the decay slope. Therefore, the drain state is very important in order to evaluate the drainage.

In this study, weight of assessment items for rock and soil slopes is deducted using AHP(Analytic Hierarchy Process). And also, weight of each performance for final evaluation is analyzed. As a result, tension crack and ground deformation make up a large proportion in all slopes, and weight of each performance based on the location of the slope does not show a big difference.

In this study, the flexural tests were performed to investigate the flexural performance of prestressed hybrid wide flange (PHWF) beams. The main test variable was the shear stud on the top steel flange for composite action with the topping slab. All the specimens had the flexural strengths exceeding their design strengths. The test results also indicate that the PHWF beams had experienced fully composite behavior with high ductility, regardless of the existence of shear studs.

In this study, the relationships between the wheat imports of South Korea and the climate of wheat production areas (the United States is selected as an example) during 1995-2014 are analyzed. While the wheat imports in South Korea have increased in the second half of the analysis period compared to the first half, wheat imports from the United States have decreased somewhat in the second half than the first half. The unit cost of wheat import from the United States is unstable in the second half due to the increasing tendency of unit cost of wheat imports since 2007 and the enhanced variability. Wheat yields of Kansas (winter wheat) and North Dakota (spring wheat) in the major wheat growing regions in the United States are affected by precipitation during growing period and high-temperature condition before harvest, respectively. The unit cost of wheat imports from the United States to South Korea was caused by the impact of fluctuations in precipitation of Kansas, rather than temperature condition of North Dakota.

Climate change, in particular temperature change, has an impact on the demand for heating and cooling. This paper explores the effect of gradually warming climate on the demand for heating and cooling in Seoul during 1995-2014 using an autoregressive distributed-lag model, a family of timeseries econometric multivariate regression model. The estimated results reveal that there are two peaks in Seoul's electricity consumption because cooling degree days (CDD) and heating degree days (HDD) are statistically highly significant. CDD’s regression coefficient for a short and long-run model is approximately twice bigger than HDD’s and the summer peak is more important in terms of electricity consumption in Seoul. Furthermore, there exists a long-run relationship between electricity consumption and the explanatory variables such as economic growth, CDD, HDD, seasonal dummies, and black out dummy.

In this study, we conducted a pilot basis for the census debris flow hazard zone is located on the roadside in some national road. Valley part by usage data for 154 points by calculating the risk and damage was also selected for the debris flow prevention research priorities. This databased to be able to systematically manage a debris flow that may occur on the national roadside.

In Korea, the anchor pull-out tests apply overseas standards because there are no suitable standards for domestic. Therefore, according to the standards, parameters of ground and anchor force appear differently. In this study, we've compared the field tests conducted in Korea with the field tests of Europe, Hong Kong and Japan and established a pull-test standards being suitable for domestic. Also, we've proposed a research plan using analysis results.

In Korea, the chemical oxygen demand(CODsed) in freshwater sediments has been measured by the potassium permanganate method used for marine sediment because of the absence of authorized analytical method. However, this method has not been fully verified for the freshwater sediment. Therefore, the use or modification of the potassium permanganate method or the development of the new CODsed analytical method may be necessary. In this study, two modified CODsed analytical methods such as the modified potassium permanganate method for CODMn and the modified closed reflux method using potassium dichromate for CODCr were compared. In the preliminary experiment to estimate the capability of the two oxidants for glucose oxidation, CODMn and CODCr were about 70% and 100% of theoretical oxygen demand(ThOD), respectively, indicating that CODCr was very close to the ThOD. The effective titration ranges in CODMn and CODCr were 3.2 to 7.5 mL and 1.0 to 5.0 mL for glucose, 4.3 to 7.5 mL and 1.4 to 4.3 mL for lake sediment, and 2.5 to 5.8 mL and 3.6 to 4.5 mL for river sediment, respectively, within 10% errors. For estimating CODsed recovery(%) in glucose-spiked sediment after aging for 1 day, the mass balances of the CODMn and CODCr among glucose, sediments and glucose-spiked sediments were compared. The recoveries of CODMn and CODCr were 78% and 78% in glucose-spiked river sediments, 91% and 86% in glucose-spiked lake sediments, 97% and 104% in glucose-spiked sand, and 134% and 107% in glucose-spiked clay, respectively. In conclusion, both methods have high confidence levels in terms of analytical methodology but show significant different CODsed concentrations due to difference in the oxidation powers of the oxidants.

일반적으로 고속도로는 대용량의 교통량을 높은 수준의 안전성과 효율성을 가지고 고속으로 이동시키기 위해 건설되었다. 국내 경부고속도로와 남해고속도로는 부산항을 기 종점으로 하는 핵심고속도로로 컨테이너차량을 포함한 수출입화물트럭의 집중으로 교통문제가 종종 발생하고 있어서 교통문제 완화를 위해서는 교통특성연구의 필요성이 제기되고 있는 상황이다. 그리하여 본 연구에서는 경부고속도로와 남해고속도로의 8차로 기본구간을 대상으로 차로별 점유율과 평균밀도의 상관관계를 통해 고속도로의 밀도추정모형을 제시하고자 하였다.

In general, protection and reinforcement measures on cut slope are often focused natural slopes to slope design are considered as slopes of safety. In this study, stability analysis is carried out and the differences to the factor were safety based on cases of analyzed erosion and surface collapse on boundary between Cut slope and Upper natural slope.