• 한국방재안전학회논문집
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• 제10권1호
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• pp.67-74
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• 2017

드론은 취미생활 및 농약 살포, 배송 등 다양한 분야에 활용되고 있다. 하지만 재난관리 분야의 활용도는 상대적으로 미미하여 구호품의 운송, 동영상의 활용 등 제한된 분야에서 일부 기능만을 사용하고 있는 것이 현실이다. 특히 재난을 전문으로 하는 기관이나 재난 전문가의 드론에 대한 이해 부족으로 활성화에 어려움이 가중된다고 판단한다. 이에 본 연구에서는 드론의 조종법에 대한 개략적인 특성과 재난관리 분야에서 드론이 활성화가 되지 않는 원인을 분석하여 제도적 측면에서는 법적 규제와 활용 측면에서는 카메라, 열 감지카메라, 적외선센서, RFID 등 센서 기반 등의 융합 적용상의 문제점을 도출하고 이에 대한 개선방안 방향에 대해 제시하고자 한다.

• 한국콘텐츠학회논문지
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• 제16권7호
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• pp.73-90
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• 2016

본 연구에서는 일본 재난관리 및 재난심리지원 체계를 살펴보고, 국내 재난심리지원체계의 구축 및 개선에 대한 시사점을 얻고자 한다. 이를 위해 일본과 한국의 재난심리지원 체계에 대한 국 내외 문헌을 중심으로 문헌연구가 이루어졌다. 일본에서는 대규모 재난 초동기에는 중앙에서 파견된 재난심리지원 인력인 재해파견정신의료팀(DPAT)에 의한 정신의료적 지원과 함께 적십자사에 의한 심리사회적 지원이 이루어지고, 재난 이후 중장기개입에 있어서는 마음케어센터에 의한 지원이 이루어지고 있다. 재난심리지원의 중앙 컨트롤타워 역할을 하는 재해시마음의정보지원센터는 재난정신건강정보지원시스템을 통해 전국적인 재난관련 데이터를 수집 분석 관리하여 전국적 수준에서 재난상황을 파악하고, 정보의 취합을 통해 중앙에서의 재난심리지원 활동을 관리한다. 일본 재난심리지원체계는 대규모 재난 시 마다 이를 계기로 하여 문제점들을 보완하고 수정하여 현재의 모습을 갖추어 왔다는 점에서 우리나라에 시사점을 준다. 연구결과에 기초하여 논의 및 시사점이 제시되었다.

• Earthquakes and Structures
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• 제10권6호
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• pp.1253-1272
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• 2016

For a nonlinear control system, there are many uncertainties, such as the structural model, controlled parameters and external loads. Although the significant progress has been achieved on the robust control of nonlinear systems through some researches on this issue, there are still some limitations, for instance, the complicated solving process, weak conservatism of system, involuted structures and high order of controllers. In this study, the computational structural mechanics and optimal control theory are adopted to address above problems. The induced norm is the eigenvalue problem in structural mechanics, i.e., the elastic stable Euler critical force or eigenfrequency of structural system. The segment mixed energy is introduced with a precise integration and an extended Wittrick-Williams (W-W) induced norm calculation method. This is then incorporated in the market-based control (MBC) theory and combined with the force analogy method (FAM) to solve the MBC robust strategy (R-MBC) of nonlinear systems. Finally, a single-degree-of-freedom (SDOF) system and a 9-stories steel frame structure are analyzed. The results are compared with those calculated by the $H{\infty}$-robust (R-$H{\infty}$) algorithm, and show the induced norm leads to the infinite control output as soon as it reaches the critical value. The R-MBC strategy has a better control effect than the R-$H{\infty}$ algorithm and has the advantage of strong strain capacity and short online computation time. Thus, it can be applied to large complex structures.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 추계학술논문발표회 논문집
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• pp.111-116
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• 2008

지구온난화로 재난 재해가 날로 증가 되고 있으며, 그 규모도 대형화 되고 있는 추세이다. 재난 재해의 원인으로서는 자연적인 것도 있지만 인위적인 것이 큰 부분을 차지하고 있다. 이러한 재난 재해를 사전에 예방 및 통제를 목적으로 환경정보를 수집하여 위험상태를 판단하기위해 다양한 환경정보수집 무선통신기술에 대한 연구가 활발하게 진행되고 있다. 본 연구는 이러한 목적을 달성하기 위해 다양한 환경정보수집 및 시간 장소 설치 등에 많은 편리성 및 효율성을 갖으며, Ubiquitous Sensor Network(USN)기반요소가 되는 Sensor Network Node를 연구 개발하였고, 이를 이용하여 USN 환경감시 및 통제 네트워크를 구축하여 실험을 통하여 타당성을 입증하였다.

• Structural Engineering and Mechanics
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• 제44권2호
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• pp.179-196
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• 2012

An eigenspace projection clustering method is proposed for structural damage detection by combining projection algorithm and fuzzy clustering technique. The integrated procedure includes data selection, data normalization, projection, damage feature extraction, and clustering algorithm to structural damage assessment. The frequency response functions (FRFs) of the healthy and the damaged structure are used as initial data, median values of the projections are considered as damage features, and the fuzzy c-means (FCM) algorithm are used to categorize these features. The performance of the proposed method has been validated using a three-story frame structure built and tested by Los Alamos National Laboratory, USA. Two projection algorithms, namely principal component analysis (PCA) and kernel principal component analysis (KPCA), are compared for better extraction of damage features, further six kinds of distances adopted in FCM process are studied and discussed. The illustrated results reveal that the distance selection depends on the distribution of features. For the optimal choice of projections, it is recommended that the Cosine distance is used for the PCA while the Seuclidean distance and the Cityblock distance suitably used for the KPCA. The PCA method is recommended when a large amount of data need to be processed due to its higher correct decisions and less computational costs.

• Smart Structures and Systems
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• 제13권6호
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• pp.1065-1094
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• 2014

Civil engineers always face the challenge of uncertainty in planning, building, and maintaining infrastructure. These works rely heavily on a variety of surveying and monitoring techniques. Unmanned aerial vehicles (UAVs) are an effective approach to obtain information from an additional view, and potentially bring significant benefits to civil engineering. This paper gives an overview of the state of UAV developments and their possible applications in civil engineering. The paper begins with an introduction to UAV hardware, software, and control methodologies. It also reviews the latest developments in technologies related to UAVs, such as control theories, navigation methods, and image processing. Finally, the paper concludes with a summary of the potential applications of UAV to seismic risk assessment, transportation, disaster response, construction management, surveying and mapping, and flood monitoring and assessment.

• Structural Engineering and Mechanics
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• 제47권6호
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• pp.741-756
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• 2013

Distributed-Steel Bar Reinforced Concrete (DSBRC) columns, a new and innovative construction technique for composite steel and concrete material which can alleviate the difficulty in the arrangement of the stirrup in the column, were studied experimentally and analytically in this paper. In addition, an ordinary steel Reinforced Concrete (SRC) column was also tested for comparison purpose. The specimens were subjected to quasi-static load reversals to model the earthquake effect. The experimental results including the hysteresis curve, resistance recession, skeleton curves and ductility ratio of columns were obtained, which showed well resistant-seismic behavior for DSBRC column. Meanwhile a numerical three-dimensional nonlinear finite-element (FE) analysis on its mechanical behavior was also carried out. The numerically analyzed results were then compared to the experimental results for validation. The parametric studies and investigation about the effects of several critical factors on the seismic behavior of the DSBRC column were also conducted, which include axial compression ratios, steel ratio, concrete strength and yield strength of steel bar.

• Geomechanics and Engineering
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• 제24권1호
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• pp.81-89
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• 2021

Uniaxial compression tests were conducted on sandstone-CGFB composite samples with different interface angles, and their strength, acoustic emission (AE), and failure characteristics were investigated. Three macro-failure patterns were identified: the splitting failure accompanied by local spalling failure in CGFB (Type-I), the mixed failure with small sliding failure along with the interface and Type-I failure (Type-II), and the sliding failure along with the interface (Type-III). With an increase of interface angle β measured horizontally, the macro-failure pattern changed from Type-I to Type-II, and then to Type-III, and the uniaxial compressive strength and elastic modulus generally decreased. Due to the small sliding failure along with the interface in the composite sample with β of 45°, AE events underwent fluctuations in peak values at the later post-peak failure stage. The composite samples with β of 60° occurred Type-III failure before the completion of initial compaction stage, and the post-peak stress-time curve initially exhibited a slow decrease, followed by a steep linear drop with peaks in AE events.

• Structural Engineering and Mechanics
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• 제91권2호
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• pp.227-238
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• 2024

Sparse regularization methods have proven effective in addressing the ill-posed equations encountered in moving force identification (MFI). However, the complexity of vehicle loads is often ignored in existing studies aiming at enhancing MFI accuracy. To tackle this issue, a double 𝑙₁ regularization method is proposed for MFI based on a response spectrum-based weighted dictionary in this study. Firstly, the relationship between vehicle-induced responses and moving vehicle loads (MVL) is established. The structural responses are then expanded in the frequency domain to obtain the prior knowledge related to MVL and to further construct a response spectrum-based weighted dictionary for MFI with a higher accuracy. Secondly, with the utilization of this weighted dictionary, a double 𝑙₁ regularization framework is presented for identifying the static and dynamic components of MVL by the alternating direction method of multipliers (ADMM) method successively. To assess the performance of the proposed method, two different types of MVL, such as composed of trigonometric functions and driven from a 1/4 bridge-vehicle model, are adopted to conduct numerical simulations. Furthermore, a series of MFI experimental verifications are carried out in laboratory. The results shows that the proposed method's higher accuracy and strong robustness to noises compared with other traditional regularization methods.

• 대한원격탐사학회지
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• 제39권5_2호
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• pp.849-858
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• 2023

지진, 산사태와 같은 재난사고현장에서 조사업무는 시설물 붕괴 등 2차 재난 피해가 발생할 수 있어 많은 위험이 따른다. 이처럼 조사자가 직접 접근하기 힘든 재난현장에서 라이다(light detection and ranging, LiDAR)가 탑재된 드론 측량시스템을 통해 고정밀의 3차원 재난정보를 안전하게 취득할 수 있는 방법을 강구할 수 있다. 이에 본 연구에서는 2023년 4월 성남시 분당구의 정자교 붕괴사고 현장을 대상으로 드론 LiDAR의 재난 현장에서의 활용 가능성을 확인하였다. 이를 위해 사고 교량에 대한 고밀도 포인트 클라우드를 수집하고, 사고 교량을 3차원 지형정보로 복원하여 10점의 지상기준점 측량 성과와 비교하였다. 그 결과, 수평방향으로의 root mean square error (RMSE)는 0.032 m, 수직방향으로 0.055 m로 확인되었다. 또한, 지상 LiDAR를 통해 같은 대상지를 측량하여 생성한 포인트 클라우드와 비교한 결과, 수직방향으로 약 0.08 m가량의 오차가 발생하였지만 전체적인 형상은 큰 차이가 없을 뿐만 아니라 전체적인 데이터 취득과 자료 처리 시간 측면에서 드론 LiDAR가 지상 LiDAR보다 효율적임을 확인할 수 있었다. 따라서 많은 위험이 따르는 재난현장에서 드론 LiDAR의 활용을 통해 안전하고 신속한 현장 조사가 가능할 것으로 판단된다.