Nach oben pdf Detecting Changes in Persistent Scatterers

Detecting Changes in Persistent Scatterers

Detecting Changes in Persistent Scatterers

In PSI (Persistent Scatterer Interferometry) the PSs are implicitly as- sumed to have a stable phase throughout a stack of images so that all images can be used for estimation. However, PSs can be expected to fade due to changes in acquisition geometry and physical changes [1, 2, 3]. A change in the zero Doppler frequency (squint angle) means that the SAR observes the PS from a different azimuth an- gle and so the azimuth amplitude response of the PS is imprinted on the return. Likewise, a change in perpendicular baseline (eleva- tion angle) imprints the elevation amplitude response of the PS on the return. The degree to which acquisition geometry affects fad- ing depends however on the physical extension of the PS and the zero Doppler or baseline spread. Fading due to physical changes can be caused by the construction and demolition of buildings with PSs suddenly appearing and disappearing or by seasonal effects such as snow cover.
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High Precision 3D Localization and Motion Analysis of Persistent Scatterers using Meter-Resolution Radar Satellite Data

High Precision 3D Localization and Motion Analysis of Persistent Scatterers using Meter-Resolution Radar Satellite Data

Many geometrical details are expected to show up in geocoded PS point clouds that can be derived from the distribution of points in 3D space. This is facilitated by the large amount of PS in combination with the high precision of localization of these points presented in the last section. A top view on two of these point clouds obtained from two stacks of the test sites Berlin and Munich is presented in Figures 58 and 59 in the UTM coordinate system. The points are colorcoded by their height deviations from the chosen reference surface (defined by the horizontal plane used in PSI), whereas the difference between lower and upper limits (blue and red colors) is 35 m and 30 m in the case of Berlin and Munich respectively. The images already give an impression on the structural details available from the spatial distribution of PS using meter-resolution SAR data; individual buildings and bridges can be identified, as well as rail tracks, which interestingly show a high density of point scatterers. In principle, the structure of the city can be derived, because the PS are mainly situated at building facades, roofs and most likely at the intersection between vertical and horizontal structures aligned towards the sensor creating double bounce lines. At a few spatially limited locations no PS are available due to the absence of dihedral or trihedral structures, or simply as an effect of viewing geometry (e.g., not all facades of each building can be seen). The areas of low PS densities can be assigned to, e.g., vegetated or unused areas, like the large part in Berlin south-west of central train station (Großer Tiergarten) or north and south-west of Munich city center (Englischer Garten and Theresienwiese), water surfaces (Berlin: river Spree; Munich: river Isar ) and areas under (de)construction affected by fast structural changes.
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Assessment of number and distribution of persistent scatterers prior to radar acquisition using open access land cover and topographical data

Assessment of number and distribution of persistent scatterers prior to radar acquisition using open access land cover and topographical data

The land cover classes ‘mineral extraction’, ‘dump sites’ and ‘construction sites’ show very large variations of the relative PS(DS) density. As these classes show strong changes over a short time period, the time lag between the acquisition date of the multispectral satellite data used for the classification of the CORINE land cover data and the acquisition date of the SAR data is very important. The larger this time lag becomes, the stronger the uncertainty of the relative PS density gets. This very high temporal variability makes the application of PSI very difficult there. The single values of the class ‘sands’ showed very different values depending on the type of geographic location. The widely sandy North Sea beaches of the Netherland and North Germany sites contain no rocks and very rarely buildings. Therefore, they show a very low PS density. As opposed to this, in the Piedmont sites the class ‘sands’ is located at riverbanks containing much more rocks and buildings in the neighborhood, which can work as PS targets. Consequently, we divided the class ‘sands’ into the two subcategories ‘sands (seashore)’ and ‘sands (riverbank)’. But it is important to notice, that the term ‘seashore’ represents widely sandy beaches with no rocks and only a few buildings, as e.g. at the Dutch and German North Sea coast. However, if the site is characterized by a coast containing significantly more rocks and therefore more potential PS targets, the relative PS density value of the class ‘sands (riverbank)’ should be used. By using freely available optical data (e.g. Landsat and ASTER) or Google Earth™, one is able to get an overview of the coast characteristic.
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Monitoring the response of roads and railways to seasonal soil movement with persistent scatterers interferometry over six UK sites

Monitoring the response of roads and railways to seasonal soil movement with persistent scatterers interferometry over six UK sites

In total, six sites were selected for this study, separated into two distinct study areas, see Figure 1 and Table 3. The prevailing climate across all sites is classified as temperate oceanic, with all areas receiving regular precipitation events throughout the year. Sites situated in the West of England receive on average 195 mm more precipitation annually than sites in Eastern England. Of the six sites, Bournemouth receives the highest annual precipitation of 835 mm, whilst Grantham receives the least (608 mm). Temperature ranges exhibit very little variation between all six sites, with typical maximum average summer temperatures of ~21 °C and minimum average winter temperatures of ~1 °C. Bournemouth receives the highest range in monthly total precipitation from 47.8 mm in July to 100.7 mm in December. Grantham receives its highest monthly precipitation in October—59.3 mm— and its lowest—36.8 mm—in February. Bristol and Bath show similar precipitation trends to Bournemouth, whilst Kings Lynn and Peterborough show similar trends to Grantham. Due to the seasonal changes in temperature and precipitation all study sites have annual profiles of soil moisture which gives rise to the conditions required for the shrinking and swelling of clay soils. Moreover, soils which are prone to seasonal waterlogging (i.e., Ground-water Gley soils, Brown soils, Pelosols and Surface-water Gley soils) may also show shrink and swell cycles in accordance to available soil moisture. In situ soil moisture data was obtained from two representative meteorological stations (data provided by the Centre for Ecology and Hydrology). The data provided in Figure 2 shows the daily averaged (from 30-minute measurements) soil Volumetric Water Content (VWC), taken at a depth of 10 cm using a Time-domain Transmission probe. As expected, the Eastern site (Redmere) held the lowest VWC value 14.8% (2 September 2016) with a range of 26.6%, whilst the Western site (Tadham Moor) had a significantly larger VWC—49.5% (1 August 2016)—and a range of 33.9%, Figure 2. Therefore, some degree of surface deformation was expected in all study sites where clay soils, or soils which have significant volume change potential, are present.
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Comparison of Orientation Angle Estimation Methodes over Coherent Scatterers

Comparison of Orientation Angle Estimation Methodes over Coherent Scatterers

In this paper, a study concerning the comparison of several different procedures for the estimation of scatterers orientation angle for the coherent backscattering case is performed. Routines were proposed for the estimation of the orientation angle of distributed as well as of deterministic (coherent) scatterers. On deterministic scatterers it is expected that all routines converge to the same value, and we verify this statement. The procedures that can be applied to the general case of non-symmetrical scatterers were found out to belong to two main classes that are fundamentally different. We indicate the cases for which the classes of routines diverge due to their fundamental difference. The Coherent Scatterers (CSs) technique is used to support the analysis and confirm the existence of general non-symmetric point-like scatterers in SAR images of urban environments. For that, experimental data using the DLR’s ESAR system at L-band over the city of Dresden, in Germany, is used.
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Persistent bias in advice-giving

Persistent bias in advice-giving

This paper presents evidence for such persistent effects from advisers’ conflicts of interest. In an experiment, we offer advisers a bonus which pays if they recommend less informed clients an investment option that is preferred only by risk-seeking individuals. Among advisers in a control group without such a bonus, almost no-one recommends this risky option. In contrast, almost half of the advisers to whom the bonus was offered do recommend it. Afterwards, advisers have to choose for themselves among the same options and then make a second recommendation for another client. For these tasks, it was explicitly stated that there would not be any bonus. Our results show that advisers who were previously exposed to the bonus were six times more likely to recommend the risky option than those who were not. We also find a similar increase in the probability that advisers choose the risky option for themselves. In consequence, being exposed to a conflict of interest in advice-giving in one single instance creates an externality on the advice which another client receives and the adviser’s own choices.
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Charitable giving and its persistent and transitory reactions to changes in tax incentives: Evidence from the German taxpayer panel

Charitable giving and its persistent and transitory reactions to changes in tax incentives: Evidence from the German taxpayer panel

with contributions between the 60 th and the 95 th quantile; and (3) price elastic taxpayers with contributions close to minus one and high contributions above the 95 th quantile of the distribution of charitable giving. Hence, we find the price elasticity to exceed one in absolute value at the tails of the distribution. In sum, taxpayers with high amounts of charitable giving confirm the prominent interpretations to be more sensitive to tax incentives as itemizing their donations potentially results in a considerable tax relief and, hence, tax planning pays off. In contrast, the behavior in the middle of the distribution of giving is rather price inelastic with price elasticities below .8 in absolute values and tax incentives are not treasure efficient (Feldstein 1975) to boost giving. Those medium donors are driven rather by income than by tax incentives. The very price and income elastic behavior at the lower tail of the distribution may reflect purposely decisions in case of rather small donations. According to theory, here the marginal utility pay off is very high and thus prone to be elastic to changes in prices, tax reliefs and income.
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Application of permanent scatterers on mining-induced subsidence

Application of permanent scatterers on mining-induced subsidence

3: Comparison of levelling and IPTs along a profile After analyzing and comparing the IPT with the ground truth we interpolated displacement maps of the leveling data.. (Fig.[r]

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Increasing Persistent Poverty in Germany

Increasing Persistent Poverty in Germany

Altogether, poverty is tending to increase in all the occupational groups, but there is no evidence that social class is becoming less significant. On the contrary, the rapid rise in poverty ratios among unskilled workers rather suggests that the social differences are becoming more marked in regard to the risk of slipping into persis- tent poverty. In the period observed around three quar- ters of all the persons in the zone of persistent poverty belong to the working classes(skilled and unskilled). Of course the risk of poverty is influenced by many other factors as well. It is particularly high for persons with a migrant background, single parents and families with more than two children _ and it accumulates accordingly for working class families with many children and a background in immigration.
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Detecting Peering Infrastructure Outages in the Wild

Detecting Peering Infrastructure Outages in the Wild

If the signal is classi�ed as a PoP-level outage, the algorithm proceeds to explore the granularity of the PoP. Here, we combine the colocation map with active traceroute measurements that we collect either opportunistically by mining public traceroute reposi- tories, such as those provided by PathCache [95], or by executing our own targeted traceroute campaigns. The traceroute paths help us to validate the outage and eliminate false positives by mapping the IP-level hops to IXPs and facility interfaces using the techniques described in [50, 76]. When the data-plane and control-plane infer- ence identify the same PoP as the source of the outage, we consider the outage as validated. We determine the length of the outage (i) by actively probing the involved interfaces and (ii) by monitoring BGP messages for changes in the communities that indicate that the paths have returned to the baseline PoP. Since we mainly rely on passive measurements via BGP, our active monitoring is rather selective and does not rely on greedily probing all infrastructure addresses. Therefore, our approach is practical and conforms to the resource limitations of publicly available measurement platforms, including RIPE Atlas [90] and Looking Glasses [48].
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Persistent bias in advice-giving

Persistent bias in advice-giving

The findings we present and the theory we develop also connect to the literature on moral reasoning and economic behavior. Central to these approaches is the notion that people care about their image of being perceived as moral and that their own actions are used to infer about themselves (Bodner and Prelec, 2003; B´ enabou and Tirole, 2004), in particular, their own moral values (B´ enabou and Tirole, 2011; Falk and Tirole, 2016). Although image concerns can refer to both, social and self-image, the latter alone can steer moral behavior. This applies, for example, to non-maximal lying in order to uphold the illusion of being honest (Mazar et al., 2008), inflicting less harm on others while seeing oneself on a video screen (Falk, 2017), or paying more under a pay-what-you- want scheme than under fixed prices to avoid appearing greedy to oneself (Gneezy et al., 2012). The theory we present and the results we report show how image concerns can be linked to moral reasoning in the context of advice-giving and how they lead to persistent biases in a setting where social image concerns were minimized.
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Persistent Identifier für wissenschaftliche Einrichtungen

Persistent Identifier für wissenschaftliche Einrichtungen

Forschungsstand 2 Forschungsstand 2.1 Persistent Identifier Im Zuge der Zugänglichkeit zu wissenschaftlicher Literatur über das Internet stellt sich die Herausforderung, wie digitale Informationsobjekte eindeutig und langfristig identifizierbar bleiben können, um das Auffinden und die zuverlässige Referenzierbarkeit von wissenschaftlichen Ergebnissen zu garantieren. Seit Anfang der 2000er Jahre erfolgte eine Reihe von Studien, die die mangelnde Persistenz von Belegen und Referenzen in wissenschaftlichen Publikationen aufzeigen (vgl. Lawrence u. a., 2001; Dellavalle, 2003; Hennessey und Ge, 2013). Das Ergebnis dieser Studien zeigt, dass die Referenzierung digitaler Informationsobjekte über einen Uniform Resource Locator (URL) keine langfristig verlässlichen Belege liefern kann, da URLs keine eineindeutige Bezeichnung für ein Objekt darstellen, sondern nur einen „Weg” hin zu einem Objekt beschreiben (vgl. Lynch, 1998). Wenn das referenzierte Objekt verschoben oder gelöscht wurde, der Service des Anbieters (Domain oder Host) nicht mehr existiert oder das Objekt umbenannt wurde, können URLs nicht mehr verarbeitet und das Objekt nicht mehr erreicht werden. Das „verschwinden” von digitalen Objekten aufgrund nicht funktionaler Links wird als Link Rot bezeichnet; im Kontext des Verweisens auf Quellen in wissenschaftlichen Publikationen spricht man von Reference Rot (vgl. Klein u. a., 2014). Ein Hauptproblem besteht darin, dass URLs sowohl ein Objekt identifizieren, als auch seinen Speicherort im Internet beschreiben (vgl. Dellavalle, 2003).
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Persistent Identifiers für dynamische Inhalte

Persistent Identifiers für dynamische Inhalte

Wenn weiterhin das rote x angezeigt wird, müssen Sie das Bild möglicherweise löschen und dann erneut einfügen... Das Bild kann nicht angezeigt werden.[r]

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Detecting and measuring nonlinearity

Detecting and measuring nonlinearity

In this section, I illustrate an empirical use of the measure of nonlinearity κ by performing an analysis of the return-risk trade-off based on the Merton ’s ( 1973 ) intertemporal capit[r]

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Detecting Semantic Business Process Model Clones

Detecting Semantic Business Process Model Clones

designers to create the same business process model in various ways. Detecting model clones, i.e., pairs of business process models sharing a certain degree of similarity can be difficult. In this paper, we propose an approach to process model clone detection based upon dominator trees and targeted at detecting semantically though not necessarily syntactically similar process models of business processes.

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Detecting outliers in time series

Detecting outliers in time series

7 Conclusion In this paper a new test to detect outlying observations was proposed. For a small outlier a likelihood ratio test has more accurate results. This changes when there is more than one outlier present or when the size of the outlier increases. Another advantage of the proposed test is that it is non-parametric, so no exact model for the time series has to be assumed. We can reduce the number of observations that have to be tested with the LR-test by rst applying the online analysis approach.

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Viscoelastometry for detecting oral anticoagulants

Viscoelastometry for detecting oral anticoagulants

effective treatments are available, but patients receiving anticoagulation therapy can be at risk of excessive bleed- ing, e.g. in trauma or emergency surgery [ 3 – 5 ]. These situations may require immediate treatment of anti- coagulant effects, whereas interventions differ between anticoagulants [ 6 , 7 ]. Depending on urgency, vitamin K antagonists (VKAs, e.g. warfarin) may be reversed using vitamin K or prothrombin complex concentrates (PCCs) [ 8 , 9 ]. Furthermore, specific reversal agents have been developed for direct oral anticoagulants (DOACs), © The Author(s). 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
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Detecting Collusion in Spatially Differentiated Markets

Detecting Collusion in Spatially Differentiated Markets

Detecting Collusion in Spatially Differentiated Markets ∗ Matthias Firgo † and Agnes K¨ ugler ‡ Abstract The empirical literature on mergers, market power and collusion in differentiated markets has mainly focused on methods relying on out- put and/or panel data. In contrast to this literature we suggest a novel approach that allows for the detection of collusive behavior among a group of firms making use of information on the spatial structure of horizontally differentiated products. By estimating best response func- tions using a spatial econometrics approach, we focus on differences in the strategic interaction in pricing between different groups of firms as well as on differences in price levels. We apply our method to the market for ski lift tickets using a unique data set on ticket prices and detailed resort-specific characteristics covering all ski resorts in Austria. We show that prices of ski resorts forming alliances are higher and increase with the size and towards the spatial center of an alliance. Strategic interaction in pricing is higher within than outside alliances. All re- sults are in line with the findings of theoretical models on collusion in horizontally differentiated markets.
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Pol-DinSAR: Polarimetric SAR Differential Interferometry Using Coherent Scatterers

Pol-DinSAR: Polarimetric SAR Differential Interferometry Using Coherent Scatterers

Polarimetric effects and their influence on DinSAR tech- niques have been addressed in the paper. Using the proposed symmetry degrees we demonstrated that many CSs in urban areas are reflection asymmetric and/or have high internal characteristic phases. For these scatterers, in the presence of Faraday or a scatterer LOS rotation, implications leading to mis-interpretation of the DinSAR phase may arise.

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InSAR forensics: tracing InSAR scatterers in high resolution optical image

InSAR forensics: tracing InSAR scatterers in high resolution optical image

This paper presents a step towards a better interpretation of the scattering mechanism of different objects and their deformation histories in SAR interferometry (InSAR). The proposed technique traces individual SAR scatterer in high resolution optical images where their geometries, materials, and other properties can be better analyzed and classified. And hence scatterers of a same object can be analyzed in group, which brings us to a new level of InSAR deformation monitoring.

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