• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.421-426
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• 2012

The purpose of this study was to investigate the knowledge of dental hygiene students of the quality assurance of dental radiation such quality assurance and related educational experiences in an effort to accelerate the preparation of a curriculum for systematic quality-assurance. The subjects in this study were 453 dental hygiene students who participated in dental radiography courses. Varied statistical analyses such as frequency analyses, reliability, chi-square, and independent samples t-tests were conducted on the data collected, using SPSS 12.0. Scheffe test was also used after one-way ANOVA as post-hoc tests. Results showed that (a) the students' acknowledge level of Radiographic Quality Assurance was $7.71{\pm}1.7$ out of 12 on average. The more theory and practical classes students took, the higher points they got (p<0.001); (b) Most of the students experienced 1-3 lessons out of 13 in practical training and 26.3% of students did not take any practical lesson. ;(c)Students who did not take any practical training got 7.20 points out of 13, students who took 1-3 lessons got 7.84 points out of 13, students who took 4-5 lessons got 7.87 points out of 13, and students who took more than 6 lessons got 8.14 points out of 13 on average. The more practical classes they took the higher acknowledge level they were. Therefore it needs to provide adequate practical lessons to them.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.508-512
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• 2007

하천유량자료는 이수, 치수, 수질관리 등의 목적으로 널리 사용되기 때문에 여러 가지 수문관측 자료 중 가장 중요하다고 할 수 있다. 그러나 우리나라의 유량자료는 여러 가지 한계를 가지고 있어서 수문자료로서 제대로 사용되지 못하고 있는 실정이다. 특히 홍수기 부자측정 방법에 의해 산정된 유량자료는 측정 여건, 방법, 기기 등의 한계로 인해 그 정확도가 더욱 낮다. 부자에 의한 유량측정은 일정거리를 유하하는 부자의 유하시간을 측정하여 평균유속을 구하고, 사전에 측량된 횡단면으로부터 유하한 개별 부자의 해당 단면적을 구하여 부분 단면적을 구한다. 구해진 개별 부자의 평균유속과 부분 단면적을 곱하여 부분유량을 산출한 후, 각 부분유량을 합하여 전체 유량을 계산한다. 이와같은 부자법은 유속-면적법이 가지고 있는 흐름 단면적 계산, 평균유속 계산의 불확실도 이외에 유하경로에 의한 불확실도, 부자 유하 시간의 불확실도, 유속 보정 계수의 불확실도 등을 포함한다. 기존 홍수 유량측정에 사용하고 있는 부자법은 육안에 의해 부자의 위치를 파악하고, 가상의 횡단선을 통과할 때 육안으로 관측하여 유하시간을 측정하는 방법이기 때문에 정확한 유량측정에 한계가 있다. 뿐만 아니라 측정에 다수의 인원이 필요하며, 홍수시 많은 비가 내리거나, 야간에 측정하는 경우에는 부자의 식별이 곤란하고 측정 여건이 불량하기 때문에 측정에 큰 애로가 있다. GPS를 이용한 전자부자는 자동으로 유속을 측정하기 위해 기존 홍수유량 측정에 사용하던 부자에 전자장치를 추가하는 것을 말한다. 본 연구에서는 GPS와 RF를 기존 봉부자에 추가하여 봉부자의 유속과 봉부자의 괘적을 측정할 수 있는 전자부자를 개발하였다. 개발한 전자부자는 기존 육안에 의한 방식보다 자동으로 정확한 유속 측정이 가능하며, 동시에 여러 개의 봉부자 사용이 가능하여 측정시간 절감이 가능하고, 비가 내리거나 야간에도 자동으로 측정이 가능한 특징을 지니고 있다. 본 연구에서 개발된 전자부자는 3개 주파수 대역을 이용할 수 있도록 개발하여, 총 15개의 부자를 동시에 투하할 수 있도록 개발하였다. 전자부자 시험결과 50m, 100m 구간 유속을 검증한 결과 50m의 경우 최대 평균 5.97%, 평균 2.38%의 상대오차를 나타냈으며, 100m의 경우 최대 5.43%, 평균 1.9%의 상대오차를 나타냈다. 자연하천 유량측정 결과 댐 방류량 대비 기존방법의 경우 약 8.2%의 상대오차를 지니고 있었으며, 전자부자의 경우 약 2.8% 상대오차를 지니고 있어, 기존 부자법에 비해 전자부자법이 5.4%의 상대오차 개선효과를 지니고 있었다. 이와같은 오차의 범위는 실제 하천에서 전자부자를 이용하여 유속측정이 가능함을 나타내는 결과이다.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.167-175
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• 2011

Evaluation of fuel consumption for the various road condition and vehicle type is necessary to perform the economic analysis of road construction which is important for the efficient design and management of road. Economic analysis of road should consider the social cost which can be divided into agency cost including initial construction expense, maintenance cost, and so on, and user cost consisting of vehicle operating cost, congestion cost, etc. Since vehicle operating cost depends on the traffic volume, fuel consumption that is a major part of vehicle operating cost will change by traffic volume as well. Fuel consumption is significantly affected by vehicle speed and road condition, especially the roughness. Thus, fuel consumption should be evaluated in terms of road condition, which is not currently considered. In this study, the estimation model of fuel consumption for the passenger cars in Korea has been developed by considering the road condition. First, the relationship between vehicle speed and fuel consumption that is used to calculate the vehicle operating cost for investment evaluation of transportation facility and the initial feasibility study of road construction was investigated. Second, with the consideration of road roughness, fuel consumption of the passenger car was measured. From the measurement, it was found that fuel consumption increased by $80m{\ell}$ per 100km driving as the roughness increased by 1m/km. Therefore, it is recommended that for the economic analysis of road design and management, the fuel consumption should be a function of road roughness.

• Journal of Korea Water Resources Association
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• v.49 no.8
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• pp.673-683
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• 2016

An Idea to estimate flexible criteria for river water use permits was proposed that takes the spatio-temporal flow variation along the river into account, which was applied to the Keumho River, one of the tributary of the Nakdong River in Korea. This idea implies the temporal division of four periods with different criteria, combining flood/non-flood seasons and irrigation/non-irrigation periods, while a single one has been applied throughout the year in the current practice. Through flow regime analysis of daily natural flow simulations at Dongchon and Seongseo, the control points of the study area, Q355 and 1Q10 for non-flood and non-irrigation period, Q275 for non-flood and irrigation period, Q185 for flood and irrigation period were suggested respectively. So, those values that subtract instream flow were determined as the flexible criteria in each season. From the comparison of current practice and the proposed method, it was estimated that $10.6\;million\;m^3/year$ is available for more water use permits without additional development of water storage. Therefore, it is conceived that flexible criteria for river water use permission suggested in this study can contribute to improve the national policies for more efficient water resources management in the future.

• Journal of the Society of Disaster Information
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• v.19 no.4
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• pp.826-833
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• 2023

Purpose: We suggest the need to utilize ESG in the safety field to prevent serious industrial accidents. Method: The Serious Accident Punishment Act, a strong serious accident prevention system, was reviewed through a review of previous research. And through comparative analysis of serious accident data from the United States and Korea, the main causes of accidents in the domestic chemical industry were derived. Result: It was determined that there was a need to induce voluntary safety management by companies through ESG management along with the Serious Accident Punishment Act, which aims to prevent corporate accidents. Through statistical analysis of accident data, it was confirmed that the scale of damage and number of deaths in domestic accidents was greater than in the United States. The reason was interpreted to be that there are many accidents caused by human causes in the country. Conclusion: In order to compensate for the lack of voluntariness in corporate safety management as well as the Serious Accident Punishment Act and encourage active safety management, the proportion of 'ESG safety evaluation' must be expanded. By using ESG as an indirect social sanction, we can expect companies to voluntarily and actively manage safety and expand safety investments in the safety field.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.335-339
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• 2014

Cowper chlorotic mottle virus (CCMV) is the 'controlled' quarantine virus as plant pathogenic virus that are classed as group VI (+) ssRNA virus that belongs to the genus Bromovirus and family Bromoviridae, When plants that are Phaseolus vulgaris, Clitoria ternatea, Nicotiana tabaccum, Glycine max, Vigna unguiculata and Vigna siensis, and Arachis hypogaea is imported in domestic. In this study, inspection system is implemented to analyze CCMV accurately and rapidly by developing RT-PCR, nested PCR, and gene insertion positive control. It is expected that the method developed in this study will contribute to the plant quarantine to be consistently utilized in the field.

• Journal of The Korean Dental Society of Anesthesiology
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• v.12 no.4
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• pp.229-233
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• 2012

Hemophilia, the most common of the inherited bleeding disorder, is the result of a deficiency of clotting factor. Since bleeding after dental treatment may cause severe or even fatal complications, people with hemophilia must be given special dental care. We report on the diagnosis and treatment of a 9-year-old boy having severe hemophilia visited our department with the chief complaints of pus discharge on the left lower molar region. In the clinical and radiographic examination, periapical abscess and dental caries were diagnosed. Considering complexity of the treatment and complication in the coagulation, it was decided to carry on the treatment under general anesthesia. Clotting factor IX concentrates were intended to provide 50-70% plasma level. Pulpectomy, resin restoration and Stainless steel crown were given under general anesthesia. Several teeth were extracted and the sockets were packed with Surgicel$^{(R)}$ (Oxidized Regenerated Cellulose, Johnson and Johnson Co. Neuchatel, Switzerland) under general anesthesia. Transpalatal arch and lingual arch were given for maintaining the extracted space before discharged. For people with severe hemophilia, factor replacement is necessary before scaling, surgery or regional block injections. Therefore, if several extractions are needed, dental care under general anesthesia would be effective and efficient management.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.1
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• pp.79-87
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• 2018

Water management impacts both methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from rice paddy fields. Although irrigation is one of the most important methods for reducing $CH_4$ emission in rice production systems it can also $N_2O$ emissions and reduce crop yields. A feasibility study on the system of rice intensification (SRI) methods with respect to irrigation requirements, greenhouse gas (GHG) emissions was conducted for either 2 or 3 years depending on the treatment in Korea. The SRI methods (i.e. SRI and midsummer drainage (MD) with conventional practice (CT)) reduced the irrigation requirement by 49.0 and 22.0 %, respectively. Global warming contribution of GHG to different depending on the type of GHG. Therefore, the emission of $CH_4$ and $N_2O$ shall be converted to Global Warming Potential (GWP). The GHG emission from the conventional practice with midsummer drainage (MD) and the SRI plots, in GWP were reduced by 49.1 and 77.1 %, respectively. Application of SRI water management method could help to improve Korea's water resources and could thus contribute to mitigation of the negative effects of global warming.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.989-992
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• 2008

In this paper, we are presenting a case that integrates ultra high strength concrete(150MPa) with surface-exposed concrete. Ahead of the field application, we carried out laboratory experiment and B/P Test for a basic property of concrete(slump flow, air content, 50cm flow time, elapse time change and compression strength) and productivity. The next, we conducted Mock-up Test using simulation specimen to evaluate infilling, surface-finishing and hydration heat of concrete. We had satisfactory results for a basic property and hydration heat of concrete. However at the time of field application, it was occurred rupture of formwork because of high lateral pressure of concrete, and then formwork was reinforced and case-in-place time was adjusted. And regardless of low and high frequency vibration, it occurred to surface-pockmark. In case that applies ultra high strength concrete to surface-exposed concrete, we estimate that it is important of systematic management and improvement of construction.

• Journal of the Korean Geotechnical Society
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• v.32 no.3
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• pp.5-13
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• 2016

Stability analysis was conducted to analyze the application of pile-supported embankment to concrete slab track on the soft ground in Korea. Pile efficiency and tension of geosynthetics in accordance with the hight of embankment and the depth of soft soil were carried out by theoretical and numerical methods. Theoretical method predicted more conservatively than the numerical method for all the cases presented herein. The settlement stability is satisfied to allowable criteria of high speed railway in Korea. The pile-supported embankment has great potential for application to soft ground condition.