• Geomechanics and Engineering
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• 제16권4호
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• pp.399-413
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• 2018

This paper addresses the issue of field measurement of excavation damage zone (EDZ) and its numerical simulation method considering both excavation unloading and blasting load effects. Firstly, a 2000 m-deep rock cavern in China is focused. A detailed analysis is conducted on the field measurement data regarding the mechanical response of rock masses subjected to excavation and blasting operation. The extent of EDZ is revealed 3.6 m-4.0 m, accounting for 28.6% of the cavern span, so it is significantly larger than rock caverns at conventional overburden depth. The rock mass mechanical response subjected to excavation and blasting is time-independent. Afterwards, based on findings of the field measurement data, a numerical evaluation method for EDZ determination considering both excavation unloading and blasting load effects is presented. The basic idea and general procedures are illustrated. It features a calibration operation of damage constant, which is defined in an elasto-plastic damage constitutive model, and a regression process of blasting load using field blasting vibration monitoring data. The numerical simulation results are basically consistent with the field measurement results. Further, some issues regarding the blasting loads, applicability of proposed numerical method, and some other factors are discussed. In conclusion, the field measurement data collected from the 2000 m-deep rock cavern and the corresponding findings will broaden the understanding of tunnel behavior subjected to excavation and blasting at great depth. Meanwhile, the presented numerical simulation method for EDZ determination considering both excavation unloading and blasting load effects can be used to evaluate rock caverns with similar characteristics.

• Geomechanics and Engineering
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• 제12권1호
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• pp.139-160
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• 2017

The bearing mechanism of tunnel-type anchorage (TTA) for suspension bridges is studied. Model tests are conducted using different shapes of plug bodies, which are circular column shape and circular truncated cone shape. The results show that the plug body of the latter shape possesses much larger bearing capacity, namely 4.48 times at elastic deformation stage and 4.54 times at failure stage compared to the former shape. Numerical simulation is then conducted to understand the mechanical and structural responses of plug body and surrounding rock mass. The mechanical parameters of the surrounding rock mass are firstly back-analyzed based on the monitoring data. The calculation laws of deformation and equivalent plastic strain show that the numerical simulation results are rational and provide subsequent mechanism analysis with an established basis. Afterwards, the bearing mechanism of TTA is studied. It is concluded that the plug body of circular truncated cone shape is able to take advantage of the material strength of the surrounding rock mass, which greatly enhances its bearing capacity. The ultimate bearing capacity of TTA, therefore, is concluded to be determined by the material strength of surrounding rock mass. Finally, recommendations for TTA design are proposed and discussed.

• 컴퓨터교육학회논문지
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• 제17권2호
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• pp.65-76
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• 2014

본 논문의 연구목적은 탐구실험중심 과학교육의 실현 방법으로 고고보드와 NetLogo를 이용한 실세계와 가상세계를 연결해주는 시뮬레이션 콘텐츠를 설계 및 개발하는데 있다. 먼저 탐구실험 수업을 위한 컴퓨터 시뮬레이션과 로봇활용교육을 이용한 수업모형을 탐색하고 가상시뮬레이션과 실제실험을 연동할 수 있도록 컴퓨터 기반의 실험 장치(MBL)을 제작하였다. 이 장치를 토대로 중등과학교과내용 중 온도변화(열평형)과 전기(저항과 전압과의 관계)단원 내용을 대상으로 시뮬레이션 콘텐츠를 제작하였다. 닫혀 있는 계에서의 온도변화가 같아지는 열평형반응을 탐구실험과 시뮬레이션으로 시각화하였으며, 전기단원의 저항과 전압과의 관계에서는 각 저항의 직렬연결을 이루었을 때, 각 저항에 걸리는 전류가 같고 전하의 흐름을 시뮬레이션 하였다. 중학생들을 대상으로 개발된 콘텐츠를 사용하게 하면서 시뮬레이션 사용 및 인터페이스에 대한 형성평가를 하였으며 컴퓨터 기반 과학교육에서 활용할 수 있는 방향성을 제시하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 춘계학술대회
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• pp.36-37
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• 2014

It is necessary to develop highly sophisticated Modeling & Simulation (M&S) system for the scientific investigation of marine accident causes and for the systematic reproduction of accidental damage procedure. To ensure an accurate and reasonable prediction of marine accidental causes, such as collision, grounding and flooding, full-scale ship M&S simulations would be the best approach using hydrocode, such as LS-DYNA code, with its Fluid-Structure Interaction (FSI) analysis technique. The objectivity of this paper is to present three full-scale ship collision, grounding and flooding simulation results of marine accidents, and to show the possibility of the scientific investigation of marine accident causes using highly sophisticated M&S system.

• 한국과학교육학회지
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• 제23권4호
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• pp.430-441
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• 2003

The purpose of this study was to investigate the effects of students' prior knowledge on scientific reasoning in solving a pendulum task with a computer simulation. Subjects were 60 Korean students: 27 fifth-grade students from an elementary school and 33 seventh grade students from a middle school located in a city with 300,000 people. This study adapted a pendulum task presented with a computer simulation on which subjects would use a pattern of multivariable causal inferences. The subjects were interviewed individually in a three-phase structured interview by the researcher and three assistants while he/she was investigating the pendulum task. This study showed that most students across grades focused heavily on demonstrating the primacy of their prior knowledge or their current hypothesis. In addition, students' theories that are part of one's prior knowledge have a significant impact on formulating, testing, and revising hypotheses. Therefore, this study supported the notion that students' prior knowledge had a strong effect on students' experimental intent and hypothesis evaluation.

• 한국초등과학교육학회지:초등과학교육
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• 제42권1호
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• pp.109-126
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• 2023

이 연구는 초등 예비교사가 모의수업 시연에서 구성한 과학적 추론을 증거-설명의 연속선 관점에서 해석하여 그들의 과학적 추론이 갖는 인식론적 의미를 조사하였다. 연구를 위해 계절 변화에 관한 모의 수업을 시연한 예비교사 2명, 고기압과 저기압 및 바람에 관한 모의수업을 시연한 예비교사 2명이 연구 참여자로 선정되었다. 예비교사의 교수발화 중에서 귀납적, 연역적(가설-연역적) 추론, 또는 귀추적 추론의 사례가 드러난 에피소드에서 각 추론이 증거-설명의 연속선의 단계에서 어떤 역할을 하는지 비교하여 예비교사의 과학적 추론이 가진 인식론적 의미를 분석하였다. 계절 변화의 원인에 관한 모의수업을 시연했던 두 예비교사는 학생들이 수집한 데이터를 비교하여 증거를 인식하였고, 증거와 가설을 비교하여 가설을 검증하는 가설-연역적 추론을 활용하여 설명을 구성하였다. 고기압과 저기압 및 바람의 방향을 주제로 모의수업을 시연했던 두 예비교사는 모둠별 데이터를 종합하여 증거로 인식하는 귀납적 추론과 선형적 논리 구조를 가진 연역적 추론을 설명구성 전략으로 선택하여 최종 설명을 제시하였다. 연구에 참여한 예비교사들은 유사한 주제의 모의수업 시연에서 대체로 비슷한 흐름의 과학적 추론을 활용하여 과학지식을 구성하였으나, 증거-설명의 연속선에서 데이터, 증거, 모델, 설명으로 전개되는 인식론적 의미 측면에서 조금씩 다른 양상을 보였다. 또한, 일부 사례를 제외하면, 공통적으로 증거에서 모델을 탐색하는 과학적 추론은 부족하였으며, 가설이나 설명모델을 추리하기 위한 귀추적 추론이 부재하였다. 이 연구에서 분석틀로 적용했던 증거-설명의 연속선 접근은 과학적 추론의 인식론적 의미를 파악할 수 있게 하며 대안적인 과학적 추론 함양 지도 방법으로 사용될 수 있음을 논의하였다.

• 한국조경학회지
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• 제14권3호
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• pp.3-19
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• 1987

The purpose of this study was to investigate desirable width / height ratio of enclosed space and to offer basic information for the design of enclosed spaces. The data of this study were gathered from the experiment through simulation. Photographic sampling of 7 campus sites located in Kwanak campus of Seoul National University and slides of perspective drawings of enclosed spaces with various D/H ratio (12, 1, 2, 4, 6, 9, 12)were used for simulation. A response format was made using the method of paired comparison and students from various departments were randomly selected for evaluation. In the method of analysis of data Thurstone's equation of Comparative Judgement was used for calculating preference score. A1so non-linear regression analysis was used for finding out relations between preference and D/H ratio. The other method of data analysis were correlation, Chi - test. And the results were summarized as follows. 1. In sketch simulation the ratio of D/H 4 got the highest preference store. This result suggests that desirable D/H ratio of enclosed space is D/H 4. And at the lower range of D/H ratio, as ratio increases, the preference score increases. At the higher range of D/H ratio, however, as ratio increases, the preference score starts to decrease from the cardinal point of D/H 4. 2. In campus photograph simulation preference is influenced by slope, elevation change of floor, trees, lawn area, familiarity, space arrangement, and exterior shape of building besides D/H ratio. 3. The preference virtue was not significantly affected by order effect. This result suggests that order effect can be ignored in the study of visual preference. 4. There are so many factors related to preference that it is difficult to explore those factors without scientific information based on scientific method. We must carry out study for scientific approach of planning and design based on precise, complete simulation technique.

• 한국과학교육학회지
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• 제22권2호
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• pp.314-335
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• 2002

The purpose of this study was to investigate the effects of students' prior knowledge on scientific reasoning process performing a task of controlling variables with computer simulation and to identify a number of problems that students encounter in scientific discovery. Subjects for this study included 60 Korean students: 27 fifth-grade students from an elementary school; 33 seventh-grade students from a middle school. The sinking objects task involving multivariable causal inference was used. The task was presented as computer simulation. The fifth and seventh-grade students participated individually. A subject was interviewed individually while the investigating a scientific reasoning task. Interviews were videotaped for subsequent analysis. The results of this study indicated that students' prior knowledge had a strong effect on students' experimental intent; the majority of participants focused largely on demonstrating their prior knowledge or their current hypothesis. In addition, studnets' theories that were part of one's prior knowledge had significant impact on formulating hypotheses, testing hypothesis, evaluating evidence, and revising hypothesis. This study suggested that students' performance was characterized by tendencies to generate uninformative experiments, to make conclusion based on inconclusive or insufficient evidence, to ignore, reject, or reinterpret data inconsistent with their prior knowledge, to focus on causal factors and ignore noncausal factors, to have difficulty disconfirming prior knowledge, to have confirmation bias and inference bias (anchoring bias).

• 대한원격탐사학회지
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• 제39권5_2호
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• pp.827-835
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• 2023

드론 라이다(Drone LiDAR)는 산지의 비탈면 정상부나 접근이 불가한 사면에 대해 근접 조사가 가능한 첨단 측량 기술로 산악지형에서 현장조사를 위한 활용이 높아지고 있다. 드론 라이다를 활용하여 지형 정보를 구축하기 위해서는 취득된 포인트 클라우드로부터 지면과 비지면 점들을 효과적으로 분리하는 전처리 과정이 필요하다. 따라서 본 연구에서는 상업용 드론에 탑재된 항공 라이다를 이용하여 산악지형의 점군 자료를 취득하고, 지면분리 기법 중 하나인 cloth simulation filtering (CSF) 알고리즘을 적용하고 정확도를 검증하였다. 알고리즘을 적용한 결과, 지면과 비지면에 대한 분리 정확도는 84.3%, kappa 계수는 0.71로 나타났고 드론 라이다 데이터를 산악지형의 산사태 현장조사에 효과적으로 활용할 수 있음을 확인하였다.

• 한국콘텐츠학회논문지
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• 제18권8호
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• pp.9-17
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• 2018

이종의 고성능 컴퓨팅 시스템은 최근 다양한 분야의 계산과학 시뮬레이션 처리 도구로 큰 각광을 받고 있다. 그러나 고성능 컴퓨팅 자원에 대한 활용 방법이 콘솔 기반으로 제공되기 때문에 컴퓨팅 자원에 대한 접근성과 활용성이 크게 떨어진다. 본 연구는 이러한 문제점을 해결하기 위해, 웹 기반의 이종 계산 자원 및 시뮬레이션 작업 관리 프로그램 개발에 대해 기술한다. 제안한 계산과학 시뮬레이션 관리 프로그램은 물리 가상 계산 자원 제어뿐만 아니라 사용자 인증, 데이터 관리, 시뮬레이션 작업 관리 등의 기능을 제공하며, 모듈식 플러그인 구조 설계를 통해 고도의 확장성을 가진다. 다분야 계산과학공학 교육 및 생명의료분야 적용 사례를 통해 그 우수성을 확인한다.