• Smart Structures and Systems
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• 제26권3호
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• pp.277-290
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• 2020

Disasters, including earthquakes and landslides, have enormous economic and social losses besides their impact on environmental disruption. Iran, and particularly its Western part, is known as an earthquake susceptible area due to numerous strong ground motions. Studying ecological changes due to climate change can improve the public and expert sector's awareness and response to future disastrous events. Synthetic Aperture Radar (SAR) data and Interferometric Synthetic Aperture Radar (InSAR) technologies are appropriate tools for modeling and surface deformation modeling. This paper proposes an efficient approach to detect ground deformation changes using Sentinel-1A. The focal point of this research is to map the ground surface deformation modeling is presented using InSAR technology over Sarpol-e Zahab on 25^th November 2018 as a study case. For surface deformation modeling and detection of the ground movement due to earthquake SARPROZ in MATLAB programming language is used and discussed. Results show that there is a general ground movement due to the Sarpol-e Zahab earthquake between -7 millimeter to +18 millimeter in the study area. This research verified previous researches on the advanced image analysis techniques employed for mapping ground movement, where InSAR provides a reliable tool for assisting engineers and the decision-maker in choosing proper policies in a time of disasters. Based on the result, 574 out of 682 damaged buildings and infrastructures due to the 2017 Sarpol-e Zahab earthquake have moved from -2 to +17 mm due to the 2018 earthquake with a magnitude of 6.3 Richter. Results show that mountainous areas have suffered land subsidence, where urban areas had land uplift.

• 한국농공학회논문집
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• 제63권5호
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• pp.95-105
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• 2021

Drought is a disaster that causes prolonged and wide scale damage. Recently, the severity and frequency of drought occurrences, and drought damage have been increased significantly due to climate change. As a result, a quantitative study of drought factors is needed to better understand and prevent future droughts. In the case of agricultural drought, several existing studies examine the economic damage caused by droughts and their causes, but these studies are not well suited to estimating crop-oriented agricultural drought damage and the factors that absolutely affect agricultural drought. This study determines which factors most affect agricultural drought. It examines meteorological factors and those related to agricultural water supplied by irrigation facilities. Rice paddy production per unit area is lower than the average from the last two years where agricultural drought occurred. We compare the relative frequency of agricultural drought impacts with irrigation facilities, effective reservoir storage, the number of water supply facilities, and the meteorological drought index such as Standardized Precipitation Index (SPI). To identify factors that affect agricultural drought, we correlate rice paddy production anomalies with irrigation water supply for the past two years. There was a high positive correlation between rice paddy production and irrigation water usage, and there was a low or moderate negative correlation between rice paddy production anomalies compared to the average of the past two years and SPI. As a result, agricultural water supply by irrigation facilities was judged to be more influential than meteorological factors in rice paddy production. This study is expected to help local governments establish policies related to agricultural drought response.

• Smart Structures and Systems
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• 제33권2호
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• pp.119-131
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• 2024

Drift angle is a significant index for diagnosing post-event structures. A common way to estimate this drift response is by using modal parameters identified under natural excitations. Although the modal parameters of shear structures cannot be identified accurately in the real environment, the identification error has little impact on the estimation when measurements from several floors are used. However, the estimation accuracy falls dramatically when there is only one accelerometer. This paper describes the susceptibility of single sensor identification to modelling error and simulations that preliminarily verified this characteristic. To make a robust evaluation from measurements of one floor of shear structures based on imprecisely identified parameters, a novel scheme is devised to approximately correct the mode shapes with respect to fictitious frequencies generated with a genetic algorithm; in particular, the scheme uses constrained minimization to take both the mathematical aspect and the realistic aspect of the mode shapes into account. The algorithm was validated by using a full-scale shear building. The differences between single-sensor and multiple-sensor estimations were analyzed. It was found that, as the number of accelerometers decreases, the error rises due to insufficient data and becomes very high when there is only one sensor. Moreover, when measurements for only one floor are available, the proposed method yields more precise and appropriate mode shapes, leading to a better estimation on the drift angle of the lower floors compared with a method designed for multiple sensors. As well, it is shown that the reduction in space complexity is offset by increasing the computation complexity.

• 한국환경과학회지
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• 제33권3호
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• pp.193-203
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• 2024

This study aims to determine the factors affecting the level of satisfaction with the Cell Broadcast Service (CBS) among citizens in Incheon. Partial least squares (PLS) regression, instead of multiple regression, was used for the analysis because it can solve multicollinearity and sample size issues. The analysis results are as follows: The factor with the greatest effect on satisfaction with CBS among Incheon citizens, was the elimination of redundancies (VIP=1.185). Therefore, local governments, government agencies, and public organizations must coordinate their ideas and collectively create guidelines to eliminate redundancies. The second most influential factor was the expansion in the broadcast medium from legal, institutional, and policy aspects (VIP=1.087). This is because differences in generation, age, gender, and personal characteristics were not considered. Therefore, it is necessary to devise a customized messaging tool through the expansion of broadcast media. The broadcast criteria of the legal, institutional, and policy perspectives comprised the third most influential factor, with a high VIP value of 1.053. Consequently, it is essential to devise a plan to avoid distributing unnecessary cell broadcast services, by establishing criteria for areas and sections, time, and the direct and indirect impact zones of a disaster. In the future, this study could be used as base data to develop policies, guidelines, and response measures for Incheon CBS. Given the lack of research on the diverse characteristics of each social class and the city traits of each region, and a lack of concrete empirical research on each factor, continuous and in-depth studies are required in the future.

• Smart Structures and Systems
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• 제33권5호
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• pp.365-374
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• 2024

This paper adopts a new approach in which nonlinear vibrations can be controlled using fuzzy controllers by optimal grey evolutionary algorithm. If the fuzzy controller cannot stabilize the systems, then the high frequency is injected into the system to assist the controller, and the system is asymptotically stabilized by adjusting the parameters. This paper uses the GM (grey model) and the neural network prediction model. The structure of the neural network is improved from a single factor, and multiple data inputs are extended to various factors and numerous data inputs. The improved model expands the applicable range of uncontrolled elements and improves the accuracy of controlled prediction, using the model that has been trained and stabilized by multiple learning. The simulation results show that the improved gray neural network model has higher prediction accuracy and reliability than the traditional GM model, improving controlled management and pre-control ability. In the combined prediction, the time series parameters and the predicted values obtained from the GM (1,1) (Grey Model of first order and one variable) are simultaneously used as the input terms of the neural network, considering the influence of the non-equal spacing of the data, which makes the results of the combined gray neural network model more rationalized. By adjusting the model structure and system parameters to simulate and analyze the controlled elements, the corresponding risk change trend graphs and prediction numerical calculation results are obtained, which also realize the effective prediction of controlled elements. According to the controlled warning principle and objective, the fuzzy evaluation method establishes the corresponding early warning response method. The goals of this paper are towards access to adequate, safe and affordable housing and basic services, promotion of inclusive and sustainable urbanization and participation, implementation of sustainable and disaster-resilient buildings, sustainable human settlement planning and manage.

• 한국재난정보학회 논문집
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• 제17권2호
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• pp.289-305
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• 2021

연구목적: "AHP 분석을 통한 공동주택 입주민의 안전 및 안심생활 수준 향상"을 위하여 상위계층과 sub 상위계층, 하위대안 요소의 중요도 및 안심생활을 위한 요인을 확인하며, 종합우선도를 확인하고자 한다. 연구방법: 본 연구에서는 공동주택 유지보수 및 제도에 관한 선행연구와 전문가 자문을 토대로 안전관리 평가요소 및 대안을 계층 구조화하였다. 연구 모형은 전문가를 상대로 쌍대비교 구성의 설문에 활용하고, 대체안 순위 결정 등을 위해 AHP분석 기법을 사용 하였다. 연구결과: 설문조사 응답 결과는 일관성을 확보하였고, 연구의 최종 목표 달성을 위해 sub상위계층 그리고 대안을 상대적 가중치 비교 등을 분석한 결과 상위계층은 공동주택 전기설비 안전점검, sub 상위계층은 안전점검/정밀점검/진단평가, 대안은 급·배수시설이 최우선적으로 중요한 것으로 확인되었다. 결론: 공동주택관리 전문가의 관리자적 시각으로 볼 때 급·배수시설, 방범안전, 전기안전이 최우선적인 대안으로 나타났다. 이는 생활안전사고의 중요성을 확보하고 안심생활의 수준 향상이 가능한 것으로 의사 결정되어 사전 예방 및 관리 강화의 대안임을 보여 주었다.

• 한국수자원학회논문집
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• 제56권11호
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• pp.775-784
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• 2023

최근 이상기후로 수공 구조물의 설계빈도를 상회하는 극한호우의 증가 경향이 뚜렷함에 따라 과거에 설계된 농업용 저수지의 안전성 검토가 필요하다. 그러나 한국농어촌공사 관할 일정 규모 이상의 저수지를 제외한 지자체 관리 저수지는 비상시 긴급 방류가 가능 저수지는 전무하다(13,685개소). 이러한 경우 이동식 사이펀을 현장에 빠르게 투입하여 사전 방류하는 방법이 긴요하며, 본 연구에서는 사전 및 긴급방류 기능을 동시에 수행할 수 있는 직경 200 mm, 최소 수위차 6 m, 420(m²/h), 10,000(m²/day)의 이동식 사이펀을 경주시 유금저수지를 대상으로 적용 가능성을 평가하였다. 테스트베드인 유금 저수지는 1945년 준공되어 공용기간이 78년 정도 경과한 시설물로 수문학적 안정성 분석 결과 현재 댐마루 구간의 최저높이는 27.15(EL.m)로 검토 홍수위 27.44(EL.m) 보다 0.29 m 낮아 제방을 통한 월류 가능성이 있고 여유고도 1.72 m 부족한 것으로 나타나 수문학 안전성을 확보하지 못하는 것으로 검토되었다. 유금저수지는 수위-유량 계측이 주기적으로 이루어진지 얼마 되지 않아 저수지의 수위-유량 관계 곡선식을 명확하게 확립하기 어려워 수위-용적 곡선을 임의로 도출하였으며 도출된 곡선을 기반으로 중소규모 노후저수지 운영 알고리즘을 통해 사전방류시간, 여수로 방류량을 고려하고 빈도별 홍수량에 따른 저수지 월류시간을 예측함으로써 사전에 대피 시간을 확보하고 붕괴위험을 저감할 수 있는 기술을 확보하였다. 직경 200 mm 이동식사이펀 1열 기준, 30년 빈도 홍수량 유입 시 상한수위 기준 80% 수준(약 30,000 m²)을 유지하면서 주민대피 시간(약 1시간)을 확보할 수 있는 최적 사전방류시간은 12시간 이전으로 분석되었다. 중소규모 노후저수지를 대상으로 사이펀 활용 사전방류기술 및 저수지 운영 알고리즘에 따라 이상기후 대비 사전에 방류를 시행하고 관리자의 의사결정을 돕는다면, 저수지 붕괴 위험지역 내의 주민들의 안전을 확보하고 주민대피 지원체계 구축을 통해 주민들의 불안감 해소, 저수지 위험상황 시 위험회피 수단 제공으로 위험요소 감소가 충분히 가능하다.

• 한국터널지하공간학회 논문집
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• 제19권1호
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• pp.11-27
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• 2017

서울시 등의 국내 주요 도심은 지역적 팽창에 따라 도로망 체계가 급격하게 발전하였고 도시민이 안락하고 풍요로운 생활을 영위하도록 전력, 통신, 상수도, 하수도, 냉 난방관로, 가스관 등이 무분별하게 개별 매설되었으며 비효율적으로 개별 관리되고 있다. 국토계획법에서는 Life-Line을 공동 수용함으로써 도로의 반복 굴착을 줄이고 도시 미관의 개선, 포장 내구성 향상에 따른 주행성능 향상 그리고 원활한 교통소통 등을 기대하는 도시계획 시설물로 공동구를 정의하고 있다. 최근 기존 도심지의 재정비 측면에서 쾌적한 도시공간 조성, 지하공간 이용 효율과 도로관리 효율 향상, 지진 및 도로함몰에 대한 재난안전성, 스마트 그리드와 전기자동차 보급과 같은 미래 생활환경 변화에 대한 신속한 대응 등을 기대할 수 있는 기존 도심지의 공동구 설치 필요성이 증가하고 있으나 국내에 설치된 모든 공동구는 신도시 개발에 따라 계획된 Life-Line을 모두 수용하도록 설치한 개착식 공동구 형태이다. 기존 도심지에서는 현재 가동중인 모든 Life-line을 모두 수용할 수 없으므로 도심지 유형별 공동구 설치 타당성 평가시스템을 활용한 설계용량 최적화 등의 새로운 연구가 필요하다. 본 연구는 신도시 공동구를 탈피하고 기존 도심지를 대상으로 평가지표에 의한 정량적 평가모델을 제시 하는 등 유형별 타당성 평가시스템을 세분화하며 정량적 평가시스템의 구현이 가능한 프로그램을 개발해 궁극적으로 도심지 공동구 활성화에 기여하고자 한다.