FLO-2D를 활용한 경사지 형상에 따른 토석류 흐름양상에 대한 수치모의

정효준,유형주,이승오,Jung, Hyo Jun,Yoo, Hyung Ju,Lee, Seung Oh 한국방재안전학회 2020 한국방재안전학회 논문집 Vol.13 No.3

국내 지형특성은 산지의 비율이 높아 토석류로 인한 피해 위험이 높다. 또한 기후변동성으로 인한 게릴라 국지성 호우는 토석류 재해의 발생빈도와 잠재적 위협을 증가시킨다. 토석류는 발생에 대한 예측이 어려워 거동특성을 분석하여 사전에 피해를 예방하는 것이 효과적이다. 본 연구는 공차와 평균경사가 각각 다른 경사지 형상을 FLO-2D를 사용하여 전파면과 경사면에 대해 발생하는 피해규모를 연구하였다. 수치모의를 통해 계산된 유속, 수심, 충격응력, 도달거리, 전파형상을 분석하였다. 수치모의 결과, 평균경사가 낮을수록 경사형상이 토석류 거동에 미치는 영향이 크며, 층격응력, 유속에서 분명한 차이를 나타낸다. 본 연구결과는 산지 주변 구조물 설계 및 시공 시 토석류 발생 피해 및 대비에 대해 참고할 자료가 될 것을 기대한다. Due to a high portion of mountainous terrains in Korea, debris flow and its disasters have been increased. In addition, recently localized flash-floods caused by climate change should add frequencies and potential risks. Grasping and understanding the behaviors of debris flow would allow us to prevent the consequent disasters caused by its occurrence. In this study, we developed a number of cases by changing the bottom slopes and their curvatures and investigated their effects on potential damage caused by the debris flow using FLO-2D. As simulating each bed slopes we analyzed for velocity, depth, impact, reach distance, and reach shape. As a result the lower the average slope, the greater the influence of its curvature and the numerical results were analyzed with showed a well-marked difference in impact stress and flow velocity. The result from this study could be referred for protecting from the debris flows when design countermeasure structures in mountainous regions.

자기관리 역량 기반 초등영어 쓰기 교수·학습 모형에 대한 초등교사의 요구와 인식

정효준(Jung, Hyo-Jun),이제영(Lee, Je-Young) 미래영어영문학회 2017 영어영문학 Vol.22 No.3

The purpose of this study is to investigate the elementary school teachers" demand and perception on the teaching-learning model for self-management competence-based English writing and to draw on its implications. In order to do so, 108 teachers who had experience in teaching English or hope to teach English were surveyed. The results of the questionnaires were as follows: First, the mean of students" interest in textbook writing activity was as low as 2.54. In order to motivate the students, many teachers used game activities and exercises. Second, the results of the questionnaire asking students" confidence to participate in writing activities were as low as 2.80. 39.8% of the respondents said that they use learning materials appropriate for the student"s level to improve their self-confidence. Third, the average for how students use various learning strategies was lowered to 2.62, suggesting that English textbooks need to provide more helpful learning strategies. Fourth, in the questionnaire asking whether to use self-evaluation in writing activities, the average value was 3.09. However, the mean of the questionnaire which asked whether self–evaluation helped to improve the writing ability was 3.28. The implications of this study are as follows: The English textbooks, currently under development, should consider students" writing level, diversify writing styles, and present practical learning strategies and self-evaluation activities. Should these points be reflected, it would be very effective in achieving goals of elementary English education.

초등영어 말하기 수업과 자기평가 연계를 위한 방안

정효준(Jung, Hyo-Jun),이재근(Lee, Jae-Keun) 경인교육대학교 교육연구원 2020 교육논총 Vol.40 No.1

본 연구에서는 초등영어 말하기 수업과 자기평가 연계를 위한 방안을 제시하기 위해 4학년 5종 영어 검정교과서의 말하기 자기평가 요소를 분석하였고, 자기평가에 대한 교사의 요구를 조사하였다. 이를 바탕으로 제시한 말하기 수업과 자기평가 연계를 위한 방안은 다음과 같다. 단원의 2차시 수업은 학생들이 단원의 주요 표현을 말하는데 익숙하지 않기 때문에 점검 및 목표 설정, 자기점검, 자기반성 및 평가, 후속학습 계획 수립의 자기평가 단계를 통해 말하기 수업과 자기평가가 연계되도록 구성하였으며, 말하기 활동이 발전된 4차시는 실천 점검 및 목표 재확인, 자기점검, 자기반성 및 평가, 피드백, 후속학습 계획 수립 등의 자기평가 단계를 통해 말하기 수업과 자기평가가 연계되도록 구성하였다. 또한, 말하기 수업과 자기평가의 연계 방안을 적용하기 위한 2, 4차시에 맞는 자기평가지를 구안하였다. 이러한 연구 결과를 바탕으로 한 후속연구에 대한 제언은 다음과 같다. 초등영어 교과서 개발 시 말하기 수업과 자기평가가 연계될 수 있게 선순환적 자기평가 과정을 단계적으로 제시해야 하며, 언어의 네 기능은 각기 다른 특징을 가지고 있기 때문에 수업과 자기평가 연계를 위한 듣기, 읽기, 쓰기 수업에 관한 연구도 이루어져야 한다. The purpose of this study is to suggest a method for linking English speaking classes with self-evaluation in elementary school. For this purpose, self-evaluation components of the speaking portion of English textbooks from all five different publishers were analyzed, and a research survey was conducted among teachers who had experienced teaching fourth grade English classes in order to examine the perceptions and needs of linking English speaking classes with self-evaluation. The research results were as follows: Most of the textbooks were constructed so that only the cognitive elements of speaking could be evaluated, and the teachers recognized the importance of students’ self-evaluation of their own speech. Speaking classes are customarily held in the second and fourth classes of each chapter. In the second class, students learn to speak the target expressions for the first time, thus self-evaluation was designed to be linked with the class through the stages of self-check, formation of speaking goals, self-monitoring, self-judgment, and a follow-up study plan. The fourth class, with students improved speaking ability, consisted of self-evaluation in stages such as practice check, goal reconfirmation, self-monitoring, self-judgment, feedback, and a follow-up study plan. For a more advanced method of linking English speaking classes with self-evaluation, the process of self-evaluation should be increasingly integral in developing elementary English textbooks. Furthermore, as the four skills of language have different characteristics, future studies should research using self-evaluation in conjunction with listening, reading, and writing.

방파제 내부 공동현상 적용을 위한 샌드매스틱 아스팔트 혼합물 시공성에 대한 수치해석

정효준(Hyo Jun Jung),유형주(Hyung Joo Yoo),양성린(Sung Lyn Yang),이승오(Seung Oh Lee) 한국연안방재학회 2021 한국연안방재학회지 Vol.8 No.2

As a breakwater gradually becomes obsolete, it becomes vulnerable to loss of its original functions and finally occurs corruption due to cavitation, scours inside, etc. The mortar grouting method, which has been in general applied in many cases, would invoke serious issues such as coastal environmental pollutions because of spilled-out cement before curing on the near sea. Thus, the sand mastic that utilizes the mastic asphalt becomes focused on as a substitute. However, the related study is hard to find in the domestic literature. In this study, therefore, the workability of sand mastic when filling up the cavitation inside a breakwater was evaluated with a 3-D numerical model, FLOW-3D software. It was intended to propose the workability index (WI) of sand mastic based on the diffusion diameter. It has been shown that the temperature and the fractions of the asphalt are the most significant parameters on the rheologic characteristics of the sand mastic. As a result, it is recommended that the asphalt mixture above 16% and the initial temperature above 150℃ when applying with a breakwater with inside cavitation.

샌드매스틱의 국내 방파제 보수공사 적용성 향상을 위한 수치해석

정효준(Hyo Jun Jung),방영준(Young Jun Bang),이승오(Seung Oh Lee) 한국연안방재학회 2021 한국연안방재학회지 Vol.8 No.4

As a breakwater gradually becomes obsolete, it becomes vulnerable to loss of its original functions and finally occurs corruption due to cavitation, scours inside, etc. The mortar grouting method, which has been in general applied in many cases, would invoke serious issues such as coastal environmental pollutions because of spilled-out cement before curing on the near sea. Thus, the sand mastic that utilizes the mastic asphalt becomes focused on as a substitute. However, the related study is hard to find in the domestic literature. In this study, therefore, the workability of sand mastic when filling up the cavitation inside a breakwater was evaluated with a 3-D numerical model, FLOW-3D. It was intended to propose the workability index (WI) of sand mastic based on the diffusion diameter. It has been shown that the temperature and the composition ratio of the asphalt are the most significant parameters on the rheologic characteristics of the sand mastic. As a result, it is recommended that the asphalt composition above 16% and the initial temperature above 150℃ when applying with a breakwater with inside cavitation.

FLO-2D를 이용한 도심지 내 토석류 방재시설 효과에 대한 수치모의

정효준 ( Hyo Jun Jung ),김동현 ( Dong Hyun Kim ),이승오 ( Seung Oh Lee ) 한국구조물진단유지관리공학회 2020 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.24 No.1

기후변동성과 지속적인 산지적용면적 증가로 인해 발생하는 토석류는 인명피해와 재산피해를 초래한다. 상용 프로그램인 FLO-2D를 통해 우면산에서 발생한 토석류에 대해서 방재시설을 적용한 경우를 모의함으로서 방재시설 적용에 따른 토석류의 흐름변화를 분석하였다. 이를 통해 도심지 산지의 적합한 사방시설을 검토하여 사방시설 확충에 효율성을 높이려 한다.

모노파일 형식 해상풍력 기초의 국부세굴 검토

정효준(Hyo Jun Jung),김영택(Young Teak Kim),유형주(Hyung Joo Yoo),이승오(Seung Oh Lee) 한국연안방재학회 2021 한국연안방재학회지 Vol.8 No.3

원격탐사를 이용한 하천 제방 변위량 측정과 취약지점 선별

방영준(Young Jun Bang),정효준(Hyo Jun Jung),이승오(Seung Oh Lee) 한국방재안전학회 2021 한국방재안전학회 논문집 Vol.14 No.1

하천 제방 변위를 사전에 예측하는 방안으로 본 연구에서는 InSAR 기법 중 Differential Interferometry(D-InSAR) 기법을 이용하여 2020년 여름 발생한 남원시 금곡교(섬진강) 인근의 제방 붕괴 지역에서 취약지점을 확인하였다. 2020년 봄과 여름 각각 5장의 sentinel-1 영상과 위성 영상 전처리 도구인 SNAP을 사용하여 2020년 8월 8일 제방 붕괴 전까지의 발생한 변위를 분석한 결과, 붕괴 발생 지역의 변위 변동성지수(Variation Index), V가 상대적으로 크게 발생하였으며 이를 통해 붕괴 전조증상을 확인할 수 있었다. 향후에 산출한 변위를 분석한 결과와 유역의 지하수위, 기온, 수위, 토양도 및 토양 수분도와 같은 수문기상학적 요인과 상관관계를 분석하여 하천 제방의 모니터링 시스템을 구축할 수 있다면 기존의 하천 제방 유지·보수 점검 시스템의 많은 한계점을 극복하고 초정밀, 자동화된 하천 제방 유지관리 기술 고도화와 국가 재난관리의 향상이 가능할 것으로 기대한다. As a method of predicting the displacement of river levee in advance, Differential Interferometry (D-InSAR) kind of InSAR techniques was used to identify weak points in the area of the levee collapes near Gumgok Bridge (Somjin River) in Namwon City, which occurred in the summer of 2020. As a result of analyzing the displacement using five images each in the spring and summer of 2020, the Variation Index (V) of area where the collapse occurred was larger than that of the other areas, so the prognostic sysmptoms was detected. If the levee monitoring system is realized by analyzing the correlations with displacement results and hydrometeorological factors, it will overcome the existing limitations of system and advance ultra-precise, automated river levee maintenance technology and improve national disaster management.

혼화강도에 따른 점착성 유사의 플록형성 실험연구

김동현(Kim, Dong Hyun),정효준(Jung, Hyo Jun),이승오(Lee, Seung Oh) 대한토목학회 2020 대한토목학회 학술대회 Vol.2020 No.10

SIND을 이용한 침수예상도를 평가하기 위한 최적 형상유사도 기법

김동현(Kim, Dong Hyun),김영인(Kim, Young In),정효준(Jung, Hyo Jun),이승오(Lee, Seung Oh) 대한토목학회 2019 대한토목학회 학술대회 Vol.2019 No.10