• 제목/요약/키워드: Time-series displacement

검색결과 112건 처리시간 0.023초

Time-series InSAR Analysis and Post-processing Using ISCE-StaMPS Package for Measuring Bridge Displacements

  • Vadivel, Suresh Krishnan Palanisamy;Kim, Duk-jin;Kim, Young Cheol
    • 대한원격탐사학회지
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    • 제36권4호
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    • pp.527-534
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    • 2020
  • This study aims to monitor the displacement of the bridges using Stanford Method for Persistent Scatterers (StaMPS) time-series Persistent Scatterer Interferometric Synthetic Aperture Radar analysis. For case study bridges: Kimdaejung bridge and Deokyang bridge, we acquired 60 and 33 Cosmo-Skymed Synthetic Aperture Radar (SAR) data over the Mokpo region and Yeosu region, respectively from 2013 to 2019. With single-look interferograms, we estimated the long-term time-series displacements over the bridges. The time-series displacements were estimated as -8.8 mm/year and -1.34 mm/year at the mid-span over the selected bridges: Kimdaejung and Deokyang bridge, respectively. This time-series displacement provides reliable and high spatial resolution information to monitor the structural behavior of the bridge for preventing structural behaviors.

Displacement prediction in geotechnical engineering based on evolutionary neural network

  • Gao, Wei;He, T.Y.
    • Geomechanics and Engineering
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    • 제13권5호
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    • pp.845-860
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    • 2017
  • It is very important to study displacement prediction in geotechnical engineering. Nowadays, the grey system method, time series analysis method and artificial neural network method are three main methods. Based on the brief introduction, the three methods are analyzed comprehensively. Their merits and demerits, applied ranges are revealed. To solve the shortcomings of the artificial neural network method, a new prediction method based on new evolutionary neural network is proposed. Finally, through two real engineering applications, the analysis of three main methods and the new evolutionary neural network method all have been verified. The results show that, the grey system method is a kind of exponential approximation to displacement sequence, and time series analysis is linear autoregression approximation, while artificial neural network is nonlinear autoregression approximation. Thus, the grey system method can suitably analyze the sequence, which has the exponential law, the time series method can suitably analyze the random sequence and the neural network method almostly can be applied in any sequences. Moreover, the prediction results of new evolutionary neural network method is the best, and its approximation sequence and the generalization prediction sequence are all coincided with the real displacement sequence well. Thus, the new evolutionary neural network method is an acceptable method to predict the measurement displacements of geotechnical engineering.

언커플시스템의 파라메트릭 모델링 (Parametric Modelling of Uncoupled System)

  • 윤문철;김종도;김광희
    • 한국기계가공학회지
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    • 제5권3호
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    • pp.36-42
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    • 2006
  • The analytical realization of uncoupled system was introduced in this study using times series and its spectrum analysis. The ARMAX spectra of time series methods were compared with the conventional FFT spectrum. Also, the response of second order system uncoupled was solved using the Runge-Kutta Gill method. In this numerical analysis, the displacement, velocity and acceleration were calculated. The displacement response among them was used for the power spectrum analysis. The ARMAX algorithm in time series was proved to be appropriate for the mode estimation and spectrum analysis. Using the separate response of first and second mode, each modes were calculated separately and the response of mixed modes was also analyzed for the mode estimation using several time series methods.

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고정산란체 기반 시계열 영상레이더 간섭기법을 활용한 부산 대심도 지하 고속화도로 건설 구간의 지반 안정성 분석 (Time-Series Interferometric Synthetic Aperture Radar Based on Permanent Scatterers Used to Analyze Ground Stability Near a Deep Underground Expressway Under Construction in Busan, South Korea)

  • 김태욱;한향선;이시웅;김우석
    • 지질공학
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    • 제33권4호
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    • pp.689-699
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    • 2023
  • Assessing ground stability is critical to the construction of underground transportation infrastructure. Surface displacement is a key indicator of ground stability, and can be measured using interferometric synthetic aperture radar (InSAR). This study measured time-series surface displacement using permanent scatterer InSAR applied to Sentinel-1 SAR images acquired from January 2017 to June 2023 for the area around a deep underground expressway under construction to connect Mandeok-dong and Centum City in Busan, South Korea. Regions of seasonal subsidence and uplift were identified, as were regions with severe subsidence after summer 2022. To evaluate stability of the ground in the construction area, the mean displacement velocity, final surface displacement, cumulative surface displacement, and difference between minimum and maximum surface displacement were analyzed. Considering the time-series surface displacement characteristics of the study area, the difference between minimum and maximum surface displacement since June 2022 was found to be the most suitable parameter for evaluating ground stability. The results identified highly unstable ground in the construction area as being to the north of the mid-lower reaches of the Oncheon-cheon River and to the west of the Suyeong River at the point where both rivers meet, with the difference between minimum and maximum surface displacement of 40~60 mm.

A new model approach to predict the unloading rock slope displacement behavior based on monitoring data

  • Jiang, Ting;Shen, Zhenzhong;Yang, Meng;Xu, Liqun;Gan, Lei;Cui, Xinbo
    • Structural Engineering and Mechanics
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    • 제67권2호
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    • pp.105-113
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    • 2018
  • To improve the prediction accuracy of the strong-unloading rock slope performance and obtain the range of variation in the slope displacement, a new displacement time-series prediction model is proposed, called the fuzzy information granulation (FIG)-genetic algorithm (GA)-back propagation neural network (BPNN) model. Initially, a displacement time series is selected as the training samples of the prediction model on the basis of an analysis of the causes of the change in the slope behavior. Then, FIG is executed to partition the series and obtain the characteristic parameters of every partition. Furthermore, the later characteristic parameters are predicted by inputting the earlier characteristic parameters into the GA-BPNN model, where a GA is used to optimize the initial weights and thresholds of the BPNN; in the process, the numbers of input layer nodes, hidden layer nodes, and output layer nodes are determined by a trial method. Finally, the prediction model is evaluated by comparing the measured and predicted values. The model is applied to predict the displacement time series of a strong-unloading rock slope in a hydropower station. The engineering case shows that the FIG-GA-BPNN model can obtain more accurate predicted results and has high engineering application value.

고무의 힘-변위 관계를 나타내는 모델링에의 볼테라 급수의 응용 (Application of Volterra Series to Modeling an Elastomer Force-Displacement Relation)

  • 성단근
    • 대한전자공학회논문지
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    • 제26권6호
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    • pp.71-78
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    • 1989
  • 비선형 시스템의 입출력 관계는 볼테라 급수로 나타낼 수 있으며 그것은 볼테라 커널에 의해 규명될 수 있다. 본 연구는 소수의 볼테라 급수항을 사용하여 계단 입력에 의한 고무의 힘-변위 관계를 모델링하는데 관한 것이다. 무한의 기울기를 가진 계단 입력을 가하여 얻어진 실험결과에서 일정한 압축시의 계단입력에 대한 결과를 예측한다. 비스코일레스틱 재료를 나타내는 현저한 특징중의 하나인 힘-변위 관계를 모델링하기 위해 2차와 3차 볼테라 급수 모델을 사용한다. 3차 볼테라 급수 모델이 2차 볼테라 급수 모델의 결과에 비해 더 좋은 결과가 얻어지고 있다.

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Monitoring Time-Series Subsidence Observation in Incheon Using X-Band COSMO-SkyMed Synthetic Aperture Radar

  • Sang-Hoon Hong
    • 대한원격탐사학회지
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    • 제40권2호
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    • pp.141-150
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    • 2024
  • Ground subsidence in urban areas is mainly caused by anthropogenic factors such as excessive groundwater extraction and underground infrastructure development in the subsurface composed of soft materials. Global Navigation Satellite System data with high temporal resolution have been widely used to measure surface displacements accurately. However, these point-based terrestrial measurements with the low spatial resolution are somewhat limited in observing two-dimensional continuous surface displacements over large areas. The synthetic aperture radar interferometry (InSAR) technique can construct relatively high spatial resolution surface displacement information with accuracy ranging from millimeters to centimeters. Although constellation operations of SAR satellites have improved the revisit cycle, the temporal resolution of space-based observations is still low compared to in-situ observations. In this study, we evaluate the extraction of a time-series of surface displacement in Incheon Metropolitan City, South Korea, using the small baseline subset technique implemented using the commercial software, Gamma. For this purpose, 24 COSMO-SkyMed X-band SAR observations were collected from July 12, 2011, to August 27, 2012. The time-series surface displacement results were improved by reducing random phase noise, correcting residual phase due to satellite orbit errors, and mitigating nonlinear atmospheric phase artifacts. The perpendicular baseline of the collected COSMO-SkyMed SAR images was set to approximately 2-300 m. The surface displacement related to the ground subsidence was detected approximately 1 cm annually around a few Incheon Subway Line 2 route stations. The sufficient coherence indicates that the satellite orbit has been precisely managed for the interferometric processing.

커플시스템의 파라메트릭 모델링 (Parametric Modelling of Coupled System)

  • 윤문철;김종도;김병탁
    • 한국기계가공학회지
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    • 제5권3호
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    • pp.43-50
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    • 2006
  • In this successive study, the analytical realization of coupled system was introduced using the times series identification and spectrum analysis, which was compared with conventional FFT spectrum. Also, the numerical responses of second order system, which is coupled, were solved using the numerical calculation of Runge-Kutta Gill method. After numerical analysis, the displacement, velocity and acceleration were acquired. Among them, the response of displacement was used for the analysis of time series spectrum. Among several time series, the ARMAX algorithm was proved to be appropriate for the spectrum analysis of the coupled system. Using the separated response of 1st and 2nd mode, the mode was calculated separately. And the responses of mixed modes were also analyzed for calculation of the mixed modes in the coupled system.

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Sustainable Surface Deformation Related with 2006 Augustine Volcano Eruption in Alaska Measured Using GPS and InSAR Techniques

  • Lee, Seulki;Kim, Sukyung;Lee, Changwook
    • 한국측량학회지
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    • 제34권4호
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    • pp.357-372
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    • 2016
  • Augustine volcano, located along the Aleutian Arc, is one of the most active volcanoes in Alaska and nearby islands, with seven eruptions occurring between 1812 and 2006. This study monitored the surface displacement before and after the most recent 2006 eruption. For analysis, we conducted a time-series analysis on data observed at the permanent GPS(Global Positioning System) observation stations in Augustine Island between 2005 and 2011. According to the surface displacement analysis results based on GPS data, the movement of the surface inflation at the average speed of 2.3 cm/year three months prior to the eruption has been clearly observed, with the post-eruption surface deflation at the speed of 1.6 cm/year. To compare surface displacements measurement by GPS observation, ENVISAT(Environmental satellite) radar satellite data were collected between 2003 and 2010 and processed the SBAS(Small Baseline Subset) method, one of the time-series analysis techniques using multiple InSAR(Interferometric Synthetic Aperture Radar) data sets. This result represents 0.97 correlation value between GPS and InSAR time-series surface displacements. This research has been completed precise surface deformation using GPS and time-series InSAR methods for a detection of precursor symptom on Augustine volcano.

SAR 영상을 활용한 지반침하의 위험평가를 위한 지표결정에 대한 연구 (A Study on the Determination of Indicators for the Risk Assessment of Ground Depression Using SAR Imageson)

  • 이효진;윤홍식;한학
    • 한국지반환경공학회 논문집
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    • 제22권7호
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    • pp.13-20
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    • 2021
  • 2015년 4월 개통한 호남고속철도 근처 노반의 침하 문제가 지속적으로 제기되고 있으며 이에 따라 호남고속철도 인근지역의 지반 안정성 또한 문제가 있을 수 있다. 위험지도를 제작하는데 있어서 지표 및 지표를 결정하는 인자를 선정하는 것은 매우 중요하다. 기존의 위험지표는 관측된 기간 중 가장 마지막 관측날을 기준으로한 최종 변위량으로 산정하는데 침하 원인과 지표의 거동을 분석하기 위해서는 시계열적인 지표변위를 확인해야한다. 또한 광범위한 지역의 경우 직접 수준측량을 실시하기에 경제적으로 비효율적이므로 SAR 영상을 이용해 지표변위를 관측하고자 하였다. 본 논문에서는 PS-InSAR기법을 이용해 시계열 지표변위를 관측하였으며 위험지표를 결정하기 위한 인자로 최종지표변위량, 누적지표변위량, 최소변위량과 최대변위량의 차를 이용해 각 인자로 위험도를 등급화하여 비교하였다. 그 결과 최종변위량의 위험도 등급과 각 인자 간 위험도 등급이 상이하였으며 위험지표를 결정하는데 있어 다양한 관점의 인자를 추가하는 것을 제안하였다. 이는 지반침하의 원인을 찾고 해결방안을 모색하는데 있어 중요한 연구가 될 것으로 기대한다.