scholarly journals Semi-automated extraction of Deviation Indexes (DI) from satellite Persistent Scatterers time series: tests on sedimentary volcanism and tectonically-induced motions

2012 ◽  
Vol 19 (6) ◽  
pp. 643-655 ◽  
Author(s):  
F. Cigna ◽  
D. Tapete ◽  
N. Casagli
Keyword(s):  
Time Series ◽  
Southern Italy ◽  
A Priori ◽  
Deformation Model ◽  
Automated Extraction ◽  
Persistent Scatterers ◽  
Information Level ◽  
Coherence Factors ◽  
The Village ◽  
The Town

Abstract. We develop a methodology based on satellite Persistent Scatterers (PS) time series and aimed to calculate two indexes which are capable to depict the deviation from a deformation model defined a priori. Through a simple mathematical approach, these indexes reproduce the visual process of identification of trend deviations that is usually performed manually by the radar-interpreter, and guide the prioritization of further interpretation for those areas recording significant variations within their motion history. First tests on semi-automated extraction of the Deviation Indexes (DI) from RADARSAT-1 PS data available over Southern Italy allowed the quantification of tectonically-induced land motions which occurred in February 2005 within the town of Naro, and also the clear recognition of the precursors to mud volcano eruptions which occurred in August 2008 in the village of St. Barbara. For these areas, the information level brought by the DI increases and adds onto that of other PS parameters, such as yearly velocity, standard deviation and coherence. Factors exerting influence on the DI are critically tackled within the discussions, together with the analysis of the potentials of these indexes for monitoring and warning activities of geohazards.

scholarly journals Constructing Adaptive Deformation Models for Estimating DEM Error in SBAS-InSAR Based on Hypothesis Testing

2021 ◽  
Vol 13 (10) ◽  
pp. 2006
Author(s):  
Jun Hu ◽  
Qiaoqiao Ge ◽  
Jihong Liu ◽  
Wenyan Yang ◽  
Zhigui Du ◽  
...  
Keyword(s):  
Time Series ◽  
Hypothesis Testing ◽  
Surface Deformation ◽  
A Priori ◽  
Least Square ◽  
Deformation Model ◽  
Phase Time ◽  
Testing Theory ◽  
Sbas Insar ◽  
Deformation Models

The Interferometric Synthetic Aperture Radar (InSAR) technique has been widely used to obtain the ground surface deformation of geohazards (e.g., mining subsidence and landslides). As one of the inherent errors in the interferometric phase, the digital elevation model (DEM) error is usually estimated with the help of an a priori deformation model. However, it is difficult to determine an a priori deformation model that can fit the deformation time series well, leading to possible bias in the estimation of DEM error and the deformation time series. In this paper, we propose a method that can construct an adaptive deformation model, based on a set of predefined functions and the hypothesis testing theory in the framework of the small baseline subset InSAR (SBAS-InSAR) method. Since it is difficult to fit the deformation time series over a long time span by using only one function, the phase time series is first divided into several groups with overlapping regions. In each group, the hypothesis testing theory is employed to adaptively select the optimal deformation model from the predefined functions. The parameters of adaptive deformation models and the DEM error can be modeled with the phase time series and solved by a least square method. Simulations and real data experiments in the Pingchuan mining area, Gaunsu Province, China, demonstrate that, compared to the state-of-the-art deformation modeling strategy (e.g., the linear deformation model and the function group deformation model), the proposed method can significantly improve the accuracy of DEM error estimation and can benefit the estimation of deformation time series.

Optimization of the time series surface deformation analysis using machine learning algorithms on the interferogram simulation data

2021 ◽  
Author(s):  
Muhammad Fulki Fadhillah ◽  
SeulKi Lee ◽  
Chang-Wook Lee
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Machine Learning Algorithms ◽  
Deformation Analysis ◽  
Support Vector ◽  
Detection Accuracy ◽  
Deformation Model ◽  
Measurement Point ◽  
Persistent Scatterers ◽  
Optimum Measurement

<p>Time-series InSAR techniques, such as Stanford Method for Persistent Scatterers (StaMPS) are commonly used to measure time-series surface deformation. This study presents a novel approach of optimized time series deformation analysis based on a support vector regression (SVR) algorithm and optimization Hot-Spot Analysis on persistent scatterers (PS). To examine the performances of the optimized process in time-series, we generated a synthetic interferogram using a Mogi model equation to construct a simulated surface deformation phase. Topography errors simulated orbital error and atmospheric error phases have been added to synthetic interferogram construction. All the synthetic interferogram based on Sentinel-1 SAR Image acquisition dates over Seoul, Korea. An SVR algorithm was used to find an optimum measurement point and reduce error points in time-series analysis. Then, the OHSA approach was implemented on the optimum measurement point through the analysis of Getis-Ord Gi* statistics. As the result, the optimization measurement point indicates refined results in the mean velocity deformation map and time-series graph. In addition, the detection accuracy can be improved by more than 10% with synthetic data. Then, the correlation coefficient between the optimization result and the deformation model shows a good correlation (> 0.8). Also, the standard deviation of time-series results can be reduced by more than 7% after optimizing the process. The proposed method is useful to detect a low deformation rate and can be implemented for several deformation cases.   </p>

scholarly journals Stationary and Non-Stationary Frameworks for Extreme Rainfall Time Series in Southern Italy

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1477 ◽  
Author(s):  
Davide De Luca ◽  
Luciano Galasso
Keyword(s):  
Time Series ◽  
Climate Models ◽  
Southern Italy ◽  
Regional Climate ◽  
Data Series ◽  
Rainfall Time Series ◽  
Annual Maximum ◽  
Data Set ◽  
Maximum Rainfall ◽  
Rainfall Events

This study tests stationary and non-stationary approaches for modelling data series of hydro-meteorological variables. Specifically, the authors considered annual maximum rainfall accumulations observed in the Calabria region (southern Italy), and attention was focused on time series characterized by heavy rainfall events which occurred from 1 January 2000 in the study area. This choice is justified by the need to check if the recent rainfall events in the new century can be considered as very different or not from the events occurred in the past. In detail, the whole data set of each considered time series (characterized by a sample size N > 40 data) was analyzed, in order to compare recent and past rainfall accumulations, which occurred in a specific site. All the proposed models were based on the Two-Component Extreme Value (TCEV) probability distribution, which is frequently applied for annual maximum time series in Calabria. The authors discussed the possible sources of uncertainty related to each framework and remarked on the crucial role played by ergodicity. In fact, if the process is assumed to be non-stationary, then ergodicity cannot hold, and thus possible trends should be derived from external sources, different from the time series of interest: in this work, Regional Climate Models’ (RCMs) outputs were considered in order to assess possible trends of TCEV parameters. From the obtained results, it does not seem essential to adopt non-stationary models, as significant trends do not appear from the observed data, due to a relevant number of heavy events which also occurred in the central part of the last century.

scholarly journals Flood history in the karst environment of Castellana-Grotte (Apulia, southern Italy)

2003 ◽  
Vol 3 (6) ◽  
pp. 593-604 ◽  
Author(s):  
M. Parise
Keyword(s):  
Rock Mass ◽  
Complex Network ◽  
Critical Analysis ◽  
Southern Italy ◽  
Karst Area ◽  
Flood Events ◽  
Karst Environment ◽  
Main Factors ◽  
The Town

Abstract. Karst environments are characterized by peculiar hydrologic features, and in particular by a very limited, if not absent, surface hydrography. Water tends to infiltrate rapidly underground through the complex network of fractures and karstic conduits in the rock mass. However, on the occasion of concentrated rainfall, as well as in case of prolonged precipitation, such network might not be able to allow flowing of large amounts of water, which causes the occurrence of floods. This contribution illustrates the flood history in a classical karst area of Southern Italy, the town of Castellana-Grotte, in Apulia. The oldest part of the town lies at the bottom of a karst valley, which was hit by many flood events in the last centuries. More than twenty of these are here documented, starting from critical analysis of existing publications and documents, integrated with additional historical researches. Aimed at reconstructing the flood history at Castellana-Grotte, the best-documented events are described, together with the main factors, which played a role in distribution and gravity of the related damage. Eventually some engineering works realized during the first decades of the last century, in order to avoid further damage on the occasion of catastrophic floods, are also described.

scholarly journals Monitoring distributed computing beyond the traditional time-series histogram

2020 ◽  
Vol 245 ◽  
pp. 03036
Author(s):  
M S Doidge ◽  
P. A. Love ◽  
J Thornton
Keyword(s):  
Time Series ◽  
Distributed Computing ◽  
Real Time ◽  
A Priori ◽  
Time Data ◽  
Use Of Time ◽  
Computing Services ◽  
Monitoring Tools ◽  
Novel Approach ◽  
Current Monitoring

In this work we describe a novel approach to monitor the operation of distributed computing services. Current monitoring tools are dominated by the use of time-series histograms showing the evolution of various metrics. These can quickly overwhelm or confuse the viewer due to the large number of similar looking graphs. We propose a supplementary approach through the sonification of real-time data streamed directly from a variety of distributed computing services. The real-time nature of this method allows operations staff to quickly detect problems and identify that a problem is still ongoing, avoiding the case of investigating an issue a-priori when it may already have been resolved. In this paper we present details of the system architecture and provide a recipe for deployment suitable for both site and experiment teams.

scholarly journals THE ERROR TERM IN THE HISTORY OF TIME SERIES ECONOMETRICS

2001 ◽  
Vol 17 (2) ◽  
pp. 424-450 ◽  
Author(s):  
Duo Qin ◽  
Christopher L. Gilbert
Keyword(s):  
Time Series ◽  
Rational Expectations ◽  
Time Series Data ◽  
A Priori ◽  
Theoretical Models ◽  
Series Data ◽  
London School ◽  
Time Series Econometrics ◽  
Cowles Commission ◽  
Modeling Strategy

We argue that many methodological confusions in time-series econometrics may be seen as arising out of ambivalence or confusion about the error terms. Relationships between macroeconomic time series are inexact, and, inevitably, the early econometricians found that any estimated relationship would only fit with errors. Slutsky interpreted these errors as shocks that constitute the motive force behind business cycles. Frisch tried to dissect the errors further into two parts: stimuli, which are analogous to shocks, and nuisance aberrations. However, he failed to provide a statistical framework to make this distinction operational. Haavelmo, and subsequent researchers at the Cowles Commission, saw errors in equations as providing the statistical foundations for econometric models and required that they conform to a priori distributional assumptions specified in structural models of the general equilibrium type, later known as simultaneous-equations models. Because theoretical models were at that time mostly static, the structural modeling strategy relegated the dynamics in time-series data frequently to nuisance, atheoretical complications. Revival of the shock interpretation in theoretical models came about through the rational expectations movement and development of the vector autoregression modeling approach. The so-called London School of Economics dynamic specification approach decomposes the dynamics of the modeled variable into three parts: short-run shocks, disequilibrium shocks, and innovative residuals, with only the first two of these sustaining an economic interpretation.

scholarly journals Long-term time-lapse microgravity and geotechnical monitoring of relict salt mines, Marston, Cheshire, U. K.

Geophysics ◽  
2012 ◽  
Vol 77 (6) ◽  
pp. B287-B294 ◽  
Author(s):  
Jamie K. Pringle ◽  
Peter Styles ◽  
Claire P. Howell ◽  
Michael W. Branston ◽  
Rebecca Furner ◽  
...  
Keyword(s):  
Time Lapse ◽  
Ground Subsidence ◽  
Near Surface ◽  
Geotechnical Monitoring ◽  
Salt Mines ◽  
History Of ◽  
Mine Workings ◽  
The Village ◽  
The Town

The area around the town of Northwich in Cheshire, U. K., has a long history of catastrophic ground subsidence caused by a combination of natural dissolution and collapsing abandoned mine workings within the underlying Triassic halite bedrock geology. In the village of Marston, the Trent and Mersey Canal crosses several abandoned salt mine workings and previously subsiding areas, the canal being breached by a catastrophic subsidence event in 1953. This canal section is the focus of a long-term monitoring study by conventional geotechnical topographic and microgravity surveys. Results of 20 years of topographic time-lapse surveys indicate specific areas of local subsidence that could not be predicted by available site and mine abandonment plan and shaft data. Subsidence has subsequently necessitated four phases of temporary canal bank remediation. Ten years of microgravity time-lapse data have recorded major deepening negative anomalies in specific sections that correlate with topographic data. Gravity 2D modeling using available site data found upwardly propagating voids, and associated collapse material produced a good match with observed microgravity data. Intrusive investigations have confirmed a void at the major anomaly. The advantages of undertaking such long-term studies for near-surface geophysicists, geotechnical engineers, and researchers working in other application areas are discussed.

Historic Preservation in Nazi Germany

2018 ◽  
Author(s):  
Joshua Hagen
Keyword(s):  
Historic Preservation ◽  
Cultural Politics ◽  
Nazi Germany ◽  
Critical Examination ◽  
National History ◽  
National Heritage ◽  
The Village ◽  
The City ◽  
The Town ◽  
Do So

This chapter offers a critical examination of historic preservationist practices to expand our understanding of the Nazi regime’s ideologies and objectives regarding historic places and national heritage. Rather than catalogue the actual techniques of historic preservation, this chapter focuses on the cultural politics animating the regime’s efforts to construct its vision of national history, heritage, and memory. To do so, the chapter surveys the Nazi regime’s efforts to “preserve” three generalized places: the city, the town, and the village

Cadres’ Voices

2019 ◽  
pp. 115-148
Author(s):  
John James Kennedy ◽  
Yaojiang Shi
Keyword(s):  
Family Planning ◽  
Policy Implementation ◽  
Reciprocal Relationship ◽  
Village Level ◽  
The Social ◽  
The Village ◽  
The Relationship ◽  
The Town ◽  
Depth Interviews ◽  
Local Leaders

While village cadres, along with town and county officials, are often portrayed as the strong arm of the state, enforcing the birth policy regardless of the social and personal costs, the relationship between villagers, cadres, and officials is, in fact, more fluid and complex. In-depth interviews with local cadres, including village leaders, midwives, and family planning cadres, as well as town and county officials, show a more dynamic and at times reciprocal relationship between local leaders and villagers. Many of the village cadres and officials interviewed admitted that it was not uncommon for births to go unregistered for years and that official birth counts and population reports compiled at the village level and sent up to the town governments were, at times, incomplete. The interviews reveal mutual noncompliance and selective policy implementation at the grassroots and even town and county levels.

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