• Tunnel and Underground Space
• /
• v.29 no.5
• /
• pp.332-345
• /
• 2019

Maximum dip vector of individual joint plane, which can be uniquely defined on the hemispherical projection plane, has been established by considering its dip and dip direction. A new stereographic projection method for the rock slope analysis which employs the maximum dip vector can intuitively predict the failure modes of rock slope. Since the maximum dip vector is uniquely projected on the maximum dip point of the great circle, the sliding direction of discontinuity plane can be recognized directly. By utilizing the maximum dip vector of discontinuity both the plane sliding and toppling directions of corresponding blocks can be discerned intuitively. Especially, by allocating the area of high dip maximum dip vector which can form the flanks of sliding block the potentiality for the formation of virtual sliding block has been estimated. Also, the potentiality of forming the triangular-sectioned sliding block has been determined by considering the dip angle of joint plane the dip direction of which is nearly opposite to that of the slope face. Safety factors of the different-shaped blocks of triangular section has been estimated and compared to the safety factor of the most hazardous block of rectangular section. For the wedge analysis the direction of crossline of two intersecting joint planes, which has same attribute of the maximum dip vector, is used so that wedge failures zone can be superimposed on the stereographic projection surface in which plane and toppling failure areas are already lineated. In addition the maximum dip vector zone of wedge top face has been delineated to extract the wedge top face-forming joint planes the orientation of which provides the vital information for the analysis of mechanical behavior of wedge block.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2018.05a
• /
• pp.39-39
• /
• 2018

우리나라는 전체 국토의 약 70%가 산악지형으로 이루어져 있고 연중 강우가 6월에서 9월에 집중되는 기후적 특성을 가지고 있다. 최근 기후변화의 영향까지 더해지면서 시간당 300mm 이상의 집중호우를 보이는 이상강우가 빈번하게 발생하고 있다. 대부분의 도시지역은 하천을 중심으로 발달되어 있어 인구 및 사회기반시설의 집약정도가 매우 높고 하천변 저지대 지역에 주거 및 상업시설이 밀집되어 있다. 기후적 지역적 특성으로 인한 홍수피해를 미연에 방지하고 피해를 최소화하기 위하여 치수 중심의 수자원 관리를 위해 노력하고 있다. 하지만 우리나라의 하천관리는 시기별 하천 수량의 급격한 변동으로 어려움을 겪고 있다. 이러한 어려움을 극복하고 효율적인 수자원 관리 및 홍수피해 저감을 위해 수계를 중심으로 20개의 다목적댐을 건설하여 운영 관리 중에 있다. 특히, 홍수기 시 댐 운영은 예상 강우에 따라 적절한 예비방류와 강우 시 효율적인 댐 운영계획이 필수적이다. 본 연구에서는 강우가 집중되는 홍수기 댐 운영 시에 예상 강우량에 따라 댐 유역 내 유량 증가에 기여하는 정도를 예측할 수 있는 유출율 예측 회귀식을 개발하였다. 유출율은 강우와 유출량의 비로 지역특성, 강우특성, 관개여부, 선행강우량, 강우이동 방향 등 다양한 요인에 의해 복잡한 메케니즘을 갖는다. 단순히 예상되는 총강우량에 따른 유출율 만으로 상호관계를 정의하기가 쉽지 않기 때문에 한국수자원공사에서 개발한 댐군 홍수조절 연계운영시스템(COSFIM)인 수문학적 연계운영모형을 활용하였다. 최근 10년간 홍수기에 발생한 강우사상별 시간단위의 수문자료(총강우량, 기저유량, 유출율, 무강우일수, 강우지속시간 등) 분석을 실시하였다. COSFIM 모형을 통한 결과를 토대로 고려항목 간 교차검증을 통해 사분위수범위의 이상치 경계를 설정하고 상관분석 결과에 따라 0.5 이상의 상관성이 높은 항목을 활용하여 예측 강우량에 따른 유출율 예측 회귀식을 도출하였다. 본 연구에서 개발한 예측 강우에 따른 유출율 예측 산정식은 댐 유역에 예상되는 강우량에 대하여 하천의 유량 증가 예측 정도를 정량적으로 제시할 수 있으며, 실제 홍수기 댐 운영 시 예상 강우량에 따라 신속하고 적절한 수문 방류 계획 수립에서 용이하게 활용할 수 있을 것으로 기대한다.

• Korean Journal of Remote Sensing
• /
• v.37 no.6_3
• /
• pp.1951-1963
• /
• 2021

Remote sensing data using earth observation satellites in agricultural environment monitoring has many advantages over other methods in terms of time, space, and efficiency. Since the sensor mounted on the satellite measures the energy that sunlight is reflected back to the ground, noise is generated in the process of being scattered, absorbed, and reflected by the Earth's atmosphere. Therefore, in order to accurately measure the energy reflected on the ground (radiance), atmospheric correction, which must remove noise caused by the effect of the atmosphere, should be preceded. In this study, atmospheric correction sensitivity analysis, inter-satellite cross-analysis, and comparative analysis with ground observation data were performed to evaluate the application of KOMPSAT-3 satellite's atmospheric correction for agricultural application. As a result, in all cases, the surface reflectance after atmospheric correction showed a higher mutual agreement than the TOA reflectance before atmospheric correction, and it is possible to produce the time series vegetation index of the same standard. However, additional research is needed for quantitative analysis of the sensitivity of atmospheric input parameters and the tilt angle.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.2
• /
• pp.368-377
• /
• 2019

The purpose of this study is to examine the present operation process and to suggest the points of improvement so that vocational education and training institutions can be activated more effectively. The subjects of this study were 250 college students who completed or attended the vocational education and training course in Seoul and Gyeonggi-do, and collected 230 data, excluding inappropriate responses. Data analysis was performed by using the statistical package program SPSS Statistics (Ver. 24: IBM, USA). In this study, frequency analysis was conducted to examine the characteristics of data, and crossover analysis was conducted mainly to investigate the correlation between categorical data. The results of this study are as follows: First, it provides information about vocational education and training course to all general high school students at the beginning of the first year of high school, and then, from the first semester of the second grade, do. Second, it is to open four major courses in beauty education at the same time. This makes it possible to acquire qualifications according to four beauty courses during the training period at the training institute rather than the private education institute where private education expenses are incurred. By training all major courses in skin, hair, make-up, and nail art, you will be given the opportunity to carefully determine the major course that fits your aptitude. Based on the results of this research, we propose a plan to improve the vocational education system for vocational high school students who are majoring in cosmetology.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.6
• /
• pp.895-906
• /
• 2018

The improvement project for school zone in Korea is occurring mostly in kindergartens and elementary schools in which children are mainly active, and is being promoted as part of measures to prevent children's traffic accidents. However, since the study on the essential installation facilities and proper level of safety facilities for School zone is lacking, this study relatively evaluated the efficiency of safety facility installation using DEA (Data Envelope Analysis) and suggested improvement plan. We built the facilities and incident data for 28 school zones in Hwaseong City. Six major facilities (Raised intersection, Raised crosswalk, Protective fence, Skid Proof, Speed hump, Speed cameras) that have proven to be effective in the preceding research were analyzed as input factors. As a result of the analysis, only 12 out of 28 showed efficiency and 16 out of efficiency. Effective groups of school zones were found to have fewer installed Protective fences, Skid Proof, and Speed cameras installations than school zones classified as ineffective groups. Protective fences were found to be efficient even if only 47% of the total extension of the school zone was installed, and the number of slip prevention facilities was 8.7 per square km. The number of subjects to be compared is 28, so this study is limited to use as a relative efficiency evaluation index, and it can be grouped into nationwide units and efficiency evaluation can be done for each group.

• Korean Journal of Remote Sensing
• /
• v.34 no.6_2
• /
• pp.1261-1272
• /
• 2018

It is important to measure the Arctic surface air temperature because it plays a key-role in the exchange of energy between the ocean, sea ice, and the atmosphere. Although in-situ observations provide accurate measurements of air temperature, they are spatially limited to show the distribution of Arctic surface air temperature. In this study, we proposed machine learning-based models to estimate the Arctic surface air temperature in summer based on buoy data and Advanced Microwave Scanning Radiometer 2 (AMSR2)satellite data. Two machine learning approaches-random forest (RF) and support vector machine (SVM)-were used to estimate the air temperature twice a day according to AMSR2 observation time. Both RF and SVM showed $R^2$ of 0.84-0.88 and RMSE of $1.31-1.53^{\circ}C$. The results were compared to the surface air temperature and spatial distribution of the ERA-Interim reanalysis data from the European Center for Medium-Range Weather Forecasts (ECMWF). They tended to underestimate the Barents Sea, the Kara Sea, and the Baffin Bay region where no IABP buoy observations exist. This study showed both possibility and limitations of the empirical estimation of Arctic surface temperature using AMSR2 data.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.21 no.5
• /
• pp.675-687
• /
• 2019

In recent years, the needs for double deck-tunnels have increased in large cities due to the increase in traffic volume and high land compensation costs. In Korea, a network type tunnel which is smaller than general road tunnels and crosses another tunnel underground is planned. In the shield tunnel joints between the existing shield tunnel and the box-type enlargement section, a partial steel-concrete joint is proposed where the bending moment is large instead of the existing full-section steel joint. In order to analysis the enlargement section of the shield tunnel diverged section to reflect the three-dimensional effect, the two-dimensional analysis model is considered to consider the column effect and the stiffness effect of the longitudinal member. A two-dimensional analysis method is proposed to reflect the stiffness of the longitudinal member and the column effect of the longitudinal point by considering the rigidity of the longitudinal member as the elastic spring point of the connecting part in the lateral model. As a result of the analysis of the model using the longitudinal member, it was considered that the structural safety of the partial steel-concrete joint can be secured by reducing the bending moment of the joint and the box member by introducing the longitudinal member having the stiffness equal to or greater than a certain value.

• Journal of the Korea Convergence Society
• /
• v.10 no.9
• /
• pp.69-74
• /
• 2019

The purpose of this study is to compare the efficiency of bacteria removal of three different types of hand washing methods. This study performed a convenient sampling of 30 volunteers in cross-over design. The study divided the 30 volunteers into three random groups. The three groups were asked to use antiseptic soap, alcohol-based hand disinfectant, and disposable wet wipes respectively. The result of the study showed that mean log reduction values after each had washing method were $-0.45({\pm}0.69)$ with antiseptic soap and water, $-1.19({\pm}0.52)$ with alcohol-based hand disinfectant and $-0.75({\pm}0.58)$ with disposable wet wipes. The difference was statistically significant when using alcohol-based hand disinfectant compared to the other two methods (p=0.000). According to this study, alcohol-based hand disinfectant was the most effective product based on bacteria removal for hand washing. Advantages of using alcohol-based hand disinfectant are that it is cost-effective and easy to buy, also eco-friendly. Therefore, to prevent infectious disease, providing alcohol-based hand disinfectant to every corner of the community will be very helpful.

• Journal of Convergence for Information Technology
• /
• v.9 no.5
• /
• pp.65-76
• /
• 2019

The purpose of this study was to investigate breast cancer its menopause in South Korean adult women using data from the seventh Korea national health and nutrition examination survey(KNHANES VII-2) 2017. The subjects were 3,414 people in total. The Data were analyzed by frequency, ${\chi}^2$ test and multiple logistic regression analysis using SPSS complex samples Win 25 program. According to the age of the subjects, breast cancer was 1.7% higher in women aged 50~59 years than aged 40~49 years, and 1.7% was significantly more frequent in women who had no drinking frequency than in almost everyday. Menopausal age was significantly higher in women under 44 years of age with breast cancer than in those over 50 years of age. According to menopause, postmenopausal breast cancer was 1.7% more than before menopause. When adjusted for age and alcohol drinking frequency, premenopausal adult women in Korea had significantly lower breast cancer frequency by 0.03 compared with postmenopausal women. Based on these results, it is important to pay attention to the management of breast cancer in young women aged 44 years or younger and multidisciplinary efforts are needed to reduce the ever-increasing prevalence of breast cancer.

• Journal of Conservation Science
• /
• v.37 no.2
• /
• pp.120-134
• /
• 2021

A Woolen carpet from the late Joseon Dynasty was unearthed in the process of repairing Seongjeonggak in Changdeokgung. Since relics are rarer than documentary records, the woolen carpet is highly valued as a relics. It is presumed to have been woven in the late 19th or early 20th century because there is a record of repairing Seongjeonggak in 1907. In the carpet, a pattern is made by inserting colored yarn dyed yellow and red onto a reddish-purple ground weave. The selvage of the woolen carpet used cotton thread, and jute is used for the warp and weft of the ground weave. The colored patterns is made of wool in the form of loop pile. Cut piles may appear occasionally when the colored yarn changes, but are almost invisible from the surface because they are pressed tightly with a shuttered weft. Making carpets with jute and wool is thought to be influenced by the Brussels carpets of the mid-18th century. Furthermore, the woolen carpet is torn and the pattern is completely unclear; however, it is understandable that the pattern is partially repeated. Microscopic and Fourier transform-Infrared spectrometer(FT-IR) analyses were performed for the above investigation. To identify the dyes used in relics, we compared them with natural dyed fabric samples based on chromaticity measurements and Ultraviolet/Visible spectrophotometer(UV-Vis) analysis. These analyses revealed that the woolen carpet's dyed green yarn did not use indigo, and reddish-purple ground weave is estimated to have used Caesalpinia sappan.