727 research outputs found
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Correspondence-driven plane-based M3C2 for quantification of 3D topographic change with lower uncertainty [Data and Source Code]
No full textThe analysis and interpretation of 3D topographic change requires methods that achieve low uncertainties in change quantification. Many recent geoscientific studies that perform point cloud-based topographic change analysis have used the multi-scale-model-to-model-cloudcomparison (M3C2) algorithm to consider the associated uncertainty. Change measured with the M3C2 approach, however, is difficult to interpret where 1) change occurs in directions different to the direction of change computation or 2) the quantified magnitudes of change are exceeded by the associated uncertainty due to a rough surface morphology. We present a correspondence-driven plane-based M3C2 approach that is tailored to quantifying small-magnitude (< 0.1 m) 3D topographic change of rough surfaces by reducing the uncertainty of quantified change. The approach 1) extracts planar surfaces in point clouds of successive epochs, 2) identifies corresponding planar surfaces between two point clouds using a binary random forest classification, and 3) calculates M3C2 distances and the associated uncertainty between the corresponding planar surfaces. This correspondence-driven plane-based M3C2 does not require recognition or reconstruction of geometrically complex objects but instead quantifies change between less complex, homologous planar surfaces. The approach further allows to relate change directly to a moving object. We apply our approach to a bi-weekly time
series of terrestrial laser scanning point clouds acquired at a rock glacier in the Austrian Alps. The approach enables a sevenfold reduction in the uncertainty associated with topographic change compared to standard M3C2. Significant change is therefore detected in around 75% of the area of change analysis, whereas standard M3C2 detects significant change in only 16% (2-week timespan) to 59% (10-week timespan) of the same area. The correspondence-driven plane-based M3C2 complements 3D change analysis in applications that aim to quantify smallmagnitude
topographic change in photogrammetric or laser scanning point clouds with low uncertainties in natural scenes which are characterised by overall rough surface morphology and by individual rigid objects with planar surfaces (e.g., rock glaciers, landslides, debris covered glaciers).
This dataset includes six point clouds acquired bi-weekly by terrestrial laser scanning in the summer of 2019.
Point clouds have been preprocessed using the following workflow:
1) MSA coregistration within all epochs using RiSCAN PRO (v. 2.11),
2) cropping of point clouds to the area of the rock glacier using a region filter in the software OPALS,
3) tiling into 10 tiles using a region filter in OPALS,
4) point cloud filtering to remove statistical outlier points in CloudCompare (v. 2.11.1) according to https://pointclouds.org/documentation/classpcl_1_1_statistical_outlier_removal.html (parameters: number of points to use for mean distance estimation: 12; standard deviation multiplier threshold (nSigma): 1.00),
5) normal computation in OPALS (parameters: -NormalsAlg robustPlane -searchMode d3 -searchRad 0.5 -neigh 200 -selmode nearest -storeMetaInfo medium -direction upwards)
Based on these datasets, the extraction of planar areas and the identification of plane correspondences were performed as described in Zahs et al. (2021)
Fully Automatic Spatiotemporal Segmentation of 3D LiDAR Time Series for the Extraction of Natural Surface Changes [Source Code, Validation Material and Validation Results]
No full textThis dataset comprises the source code to perform fully automatic spatiotemporal segmentation in time series of topographic surface change data (Python scripts). Further provided is the validation material of the resulting extraction of 4D objects-by-change at the study site of a sandy beach in The Netherlands, together with results of the validation as aggregated expert evaluations. Details on the method and workflow are given in the corresponding paper:
Geographic observation benefits from the increasing availability of time series of 3D geospatial data, which allow analysis of change processes at high temporal detail and over extensive periods. In this context, the demand for advanced methods to detect and extract topographic surface changes from these 4D geospatial data emerges. Changes in natural scenes occur with varying magnitude, duration, spatial extent, and change rate, and the timing of their occurrence is not known. Standard pairwise change detection requires the selection of fixed analysis periods and the specification of magnitude thresholds to determine accumulation or erosion forms. In settings with continuous surface morphology and dynamic changes to the surface due to material transport, such change forms are typically temporary and may be missed or aggregated if they occur with spatial and/or temporal overlap. This is overcome with the extraction of 4D objects-by-change (4D-OBCs). These objects are obtained by firstly detecting surface changes in the temporal domain at locations in the scene. Subsequently, they are spatially delineated by considering the full history of surface change during region growing from the seed location of a detected change. To perform this spatio¬temporal segmentation systematically for entire 3D time series, we develop a fully automatic approach of seed detection and selection, combined with locally adaptive thresholding for region growing of individual objects with varying change properties. We apply our workflow to a five-months hourly time series of around 3,000 terrestrial laser scanning point clouds acquired for coastal monitoring at a sandy beach in The Netherlands. This provides 2,021 4D-OBCs as extracted accumulation or erosion forms. Results are validated through majority agreement of six expert analysts, who evaluate the segmentation performance at sample locations throughout the scene. Accordingly, our method extracts surface changes with an error of omission of 4.7 % and an error of commission of 16.6 %. We examine the results and provide considerations how postprocessing of segments can further improve the change analysis workflow. The developed approach thereby provides a powerful tool for automatic change analysis in 4D geospatial data, namely to detect and delineate natural surface changes across space and time
Research Data supporting the paper: Synthetic Control over the Binding Configuration of Luminescent sp³-Defects in Single-Walled Carbon Nanotubes
No full textUnderlying data for all figures in the paper "Synthetic Control over the Binding Configuration of Luminescent sp3-Defects in Single-Walled Carbon Nanotubes" , Nat. Commun. 2021, 12, 2119
Hells Bells project - results of sampling campaign in February 2020
No full textThis data set compiles the results of water chemical analyses as well as bulk chemical analyses of the particles suspended in the water columns of cenotes (sinkholes) obtained during a sampling campaign in Mexico in February 2020. Three stratified cenotes from North-Eastern Yucatán Peninsula were investigated: El Zapote and Siete Bocas with Hells Bells underwater speleothems and cenote Angelita without these structures. The goal of the sampling and analyses was to obtain a high depth resolution of water data around the pelagic redoxclines of the cenotes for a better understanding of the biogeochemical processes and particle formation in these particular water layers, especially with regard to the biologically promoted precipitation of calcite (Ritter et al., 2019). This process is apparently involved in the formation of underwater speleothems termed as Hells Bells. The comparison of cenotes with Hells Bells (El Zapote and Siete Bocas) with a similar cenote without Hells Bells (Angelita) allows to identify the prerequisites for biologically promoted calcite precipitation and thus, Hells Bells formation.
Furthermore, cenote Xcolac from the northern-central Yucatán Peninsula was investigated. Prior studies indicated that Hells Bells-like underwater speleothems might occur in cenote Xkolac (Ritter S.M., 2020). In order to verify, the cenote was explored and investigated in February 2020 by a team of divers and scientists. Below ~52 m water depth, the limestone walls actually revealed brownish calcitic coatings forming pine-cone like structures at overhangs (see video: Ritter et al., 2021). These novel underwater speleothems were termed as "Piñas de Yucatán". The hydrogeochemistry around the pelagic redoxcline indicates biologically-promoted calcite precipitation in the water depth level at which sulfide is re-oxidized to elemental sulfur.
Based on this discovery, Hells Bells and Piñas de Yucatán might represent a novel sub-type of underwater speleothems, the redoxithems. This special kind of speleothems are formed by a common formation mechanism, which is the microbially promoted calcite precipitation in pelagic redoxclines of very stagnant aquatic systems
Methodenprobleme einer Chronologie der Merowingerzeit in Süddeutschland. Eine Diskussion anhand von Matthias Friedrich „Archäologische Chronologie und historische Interpretation: Die Merowingerzeit in Süddeutschland“ (2016) [Supplement]
No full textDrei Tabellen zur Relativchronologie der Merowingerzeit und ihrer Phasengliederung anhand von Typen von Grabfunden
Fish primary embryonic pluripotent cells assemble into retinal tissue mirroring in vivo early eye development - in vivo imaging of OV formation
No full textDevelopment of a functional retina is accompanied by several morphological events transitions that ultimately result in the formation of a functional retina. One of them is the formation of the OV. When fish-derived organoids were generated with reduced cell-seeding density by 50%, the organoids formed individual domains reminiscent of the forming optic vesicle in vivo. To address the mode of OV formation in fish organoids, we employed live imaging of Rx3::H2B-GFP-derived organoids from day 1 to day 2 of development. This dataset is a raw data from live imaging of Rx3::H2B-GFP-derived organoids from day 1 to day 2 of development performed on the 16× detection MuVi SPIM Multiview light-sheet microscope (Luxendo Light-sheet, Bruker Corporation)
SO2 and BrO emissions of Masaya volcano from 2014 to 2020 [Research Data]
No full textEXCERPT FROM ABSTRACT: Masaya (Nicaragua, 12.0°N, 86.2°W; 635m a.s.l.) is one of the few volcanoes hosting a lava lake, today. This study has two foci: (1) discussing the state of the art of long-term SO2 emission flux monitoring with the example of Masaya and (2) the provision and discussion of a continuous data set on volcanic gas data with a large temporal coverage, which is a major extension of the empirical database for studies in volcanology as well as atmospheric bromine chemistry. We present time series of SO2 emission fluxes and BrO/SO2 molar ratios in the gas plume of Masaya from March 2014 to March 2020
Discursive construction of neighborhood across Brooklyn: A corpus-ethnographic approach - Corpus Data
No full textThis data set consists of several sub-corpora used for the analysis of the discursive construction of 'neighborhood' in Brooklyn, New York. It comprises orthographic transcriptions of 200 spoken interviews (BK_SpokenRA), the written contents of 20 Brooklyn neighborhood organization websites (BK_OrgaWeb), five years of press releases from the Brooklyn Borough president published between January 2014 and March 2019 (BK_BBHPR), and online restaurant reviews from Yelp.com collected between October 2018 and July 2019 (BK_Yelp)
Die Zukunft des kunsthistorischen Publizierens [XML-Version]
No full textDer Sammelband „Zur Zukunft des kunsthistorischen Publizierens“ – erschienen als PDF-E-Book, HTML-Version und Print-on-Demand-Ausgabe – wird hier zusätzlich als angereichte XML-Version publiziert.
Zum Buch: Das wissenschaftliche Publikationswesen ist im Umbruch begriffen, am Digitalen als universellem game changer kommt niemand vorbei. Ob in diesem Feld das gedruckte Buch in Zukunft das gängige Modell sein wird, ist sehr zu bezweifeln. Vielmehr bietet sich das Internet als äußerst flexibles Medium an, das einerseits einen deutlichen Mehrwert liefert, andererseits aber auch geläufige Rezeptionsweisen ermöglicht. Welche Möglichkeiten das digitale Publizieren in vielerlei Hinsicht eröffnet, wird in diesem Band in einer Reihe von 14 Aufsätzen aus kunsthistorischer Perspektive beleuchtet.
Das Experiment: Der Beitrag von Christof Schöch (https://doi.org/10.11588/arthistoricum.663.c9210) in diesem Band diente dem Heidelberger arthistoricum.net-Team als Anregung, Anforderungen an Daten in den Blick zu nehmen, die primär der maschinellen Weiterverarbeitung von Forschungsliteratur dienen sollen und nicht der „klassischen“ lesenden Lektüre. Dieser Sammelband wurde zum selbstreflexiven Experimentierfeld für die fünf von Schöch formulierten Anforderungen an maschinelesbare wissenschaftliche Publikationen, von denen immerhin drei erfüllt und das redaktionelle wie technische Vorgehen hier dokumentiert werden konnten: Die Anreicherung mit Metadaten, die Kodierung von Textstrukturen sowie die semantische Datenanreicherung in Form von Entitäten und Konzepten und deren Verknüpfung mit der Gemeinsamen Normdatei (GND) und der Wissensdatenbank Wikidata. Weiteres zum konkreten Vorgehen siehe den Beitrag von Effinger/Krabbes in diesem Band (https://doi.org/10.11588/arthistoricum.663.c10517)
Good decision vs. good results: Outcome bias in the evaluation of financial agents [Dataset]
No full textWe document outcome bias in situations where an agent makes risky financial
decisions for a principal. In three experiments, we show that the principal’s eval-
uations and financial rewards for the agent are strongly affected by the random
outcome of the risky investment. This happens despite her exact knowledge of the
investment strategy, which can, therefore, be assessed independently of the out-
come. The principal thus judges the same decision by the agent differently,
depending on factors that the agent has no influence on. The effect of outcomes
persists in a setting where principals communicate a preferred investment level.
Principals are more satisfied with the agent after a random success when the agent
did not follow the requested investment level, than after a failed investment that
followed their explicit request