218 research outputs found
Doppler radar observation, CG lightning activity and aerial survey of a multiple downburst in southern Germany on 23 March 2001
Two downburst events from one thunderstorm are investigated, which occurred on 23 March 2001, in Germany's climatologic annual minimum of downburst activity. Observations by two Doppler radars are combined with hail reports, ground lightning detection and an aerial survey conducted after the event. The downburst-producing storm had formed at a synoptic convergence
line within the warm sector of a cyclone. It had a remarkably high propagation speed of up to 31 m s−1 corresponding to the midtropospheric flow. Thus, by superposition with the storm motion, even two weak downbursts were sufficient to cause the observed damage of F1 and F2 intensity, respectively. While in its late stages, the storm was dynamically characterized by lower- and midtropospheric divergence; at about the time of the first downburst, a mesocyclonic vortex signature was verified. Aside from midtropospheric dry air entrainment, a thermodynamic explanation for the triggering of the two downbursts by melting of small hail according to recent findings by Atlas et al. [Atlas, D., Ulbrich, C.W., Williams, C.R., 2004. Physical origin of a wet microburst: observations and theory. J. Atmos. Sci. 61, 1186–1196] appears probable. Despite the lack of warnings to the public, the storm's
potential for hail and strong straight-line winds was detected by the German weather service radar software CONRAD more than a half hour before the downbursts occurred
Towards a Neuronally Consistent Ontology for Robotic Agents
The Collaborative Research Center for Everyday Activity Science & Engineering
(CRC EASE) aims to enable robots to perform environmental interaction tasks
with close to human capacity. It therefore employs a shared ontology to model
the activity of both kinds of agents, empowering robots to learn from human
experiences. To properly describe these human experiences, the ontology will
strongly benefit from incorporating characteristics of neuronal information
processing which are not accessible from a behavioral perspective alone. We,
therefore, propose the analysis of human neuroimaging data for evaluation and
validation of concepts and events defined in the ontology model underlying most
of the CRC projects. In an exploratory analysis, we employed an Independent
Component Analysis (ICA) on functional Magnetic Resonance Imaging (fMRI) data
from participants who were presented with the same complex video stimuli of
activities as robotic and human agents in different environments and contexts.
We then correlated the activity patterns of brain networks represented by
derived components with timings of annotated event categories as defined by the
ontology model. The present results demonstrate a subset of common networks
with stable correlations and specificity towards particular event classes and
groups, associated with environmental and contextual factors. These neuronal
characteristics will open up avenues for adapting the ontology model to be more
consistent with human information processing.Comment: Preprint of paper accepted for the European Conference on Artificial
Intelligence (ECAI) 2023 (minor typo corrections
The perception of dynamic and static facial expressions of happiness and disgust investigated by ERPs and fMRI constrained source analysis
A recent functional magnetic resonance imaging (fMRI) study by our group demonstrated that dynamic emotional faces are more accurately recognized and evoked more widespread patterns of hemodynamic brain responses than static emotional faces. Based on this experimental design, the present study aimed at investigating the spatio-temporal processing of static and dynamic emotional facial expressions in 19 healthy women by means of multi-channel electroencephalography (EEG), event-related potentials (ERP) and fMRI-constrained regional source analyses. ERP analysis showed an increased amplitude of the LPP (late posterior positivity) over centro-parietal regions for static facial expressions of disgust compared to neutral faces. In addition, the LPP was more widespread and temporally prolonged for dynamic compared to static faces of disgust and happiness. fMRI constrained source analysis on static emotional face stimuli indicated the spatio-temporal modulation of predominantly posterior regional brain activation related to the visual processing stream for both emotional valences when compared to the neutral condition in the fusiform gyrus. The spatio-temporal processing of dynamic stimuli yielded enhanced source activity for emotional compared to neutral conditions in temporal (e.g., fusiform gyrus), and frontal regions (e.g., ventromedial prefrontal cortex, medial and inferior frontal cortex) in early and again in later time windows. The present data support the view that dynamic facial displays trigger more information reflected in complex neural networks, in particular because of their changing features potentially triggering sustained activation related to a continuing evaluation of those faces. A combined fMRI and EEG approach thus provides an advanced insight to the spatio-temporal characteristics of emotional face processing, by also revealing additional neural generators, not identifiable by the only use of an fMRI approach
New Developments in the SCIAMACHY Level 2 Ground Processor Towards Version 7
SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric ChartographY) aboard ESA’s
environmental satellite ENVISAT observed the Earth’s atmosphere in limb, nadir, and solar/lunar occultation
geometries covering the UV-Visible to NIR spectral range. It is a joint project of Germany, the Netherlands and
Belgium and was launched in February 2002. SCIAMACHY doubled its originally planned in-orbit lifetime
of five years before the communication to ENVISAT was severed in April 2012, and the mission entered its
post-operational phase.
In order to preserve the best quality of the outstanding data recorded by SCIAMACHY, data processors are still
being updated. This presentation will highlight three new developments that are currently being incorporated into
the forthcoming Version 7 of ESA’s operational Level 2 processor:
1. Tropospheric BrO, a new retrieval based on the scientific algorithm of (Theys et al., 2011). This algorithm had originally been developed for the GOME-2 sensor and was later adapted for SCIAMACHY.
2. Improved cloud flagging using limb measurements (Liebing, 2015). Limb cloud flags are already part of
the SCIAMACHY L2 product. They are currently calculated employing the scientific algorithm developed by
(Eichmann et al., 2015). Clouds are categorized into four types: water, ice, polar stratospheric and noctilucent
clouds. High atmospheric aerosol loadings, however, often lead to spurious cloud flags, when aerosols had been
misidentified as clouds. The new algorithm will better discriminate between aerosol and clouds. It will also have a
higher sensitivity w.r.t. thin clouds.
3. A new, future-proof file format for the level 2 product based on NetCDF. The data format will be aligned and harmonized with other missions, particularly GOME and Sentinels. The final concept for the new format is still under discussion within the SCIAMACHY Quality Working Group
Исследование величины наклепанного слоя при обработке стали 40Х концевыми фрезами из быстрорежущей стали с разными углами винтовой стружечной канавки
Объект исследования – концевые фрезы из быстрорежущей стали Р6М5 с разными углами наклона винтовой стружечной канавки в 20°, 30°, 45° и концевая фреза с волнообразной режущей кромкой.
Предмет исследования – влияние на величину наклепанного слоя после обработки фрезерованием стали 40Х.
Цель. Исследовать величину наклепанного слоя при обработке стали 40Х концевыми фрезами из быстрорежущей стали с разными углами наклона винтовой канавки, выявить меньшую величину наклепанного слоя, определить конструкцию и геометрию концевых фрез для улучшения качества обработки стали 40Х.
Тема диссертации актуальна для производства корпусов сборного инструмента на предприятии ООО "ПК МИОН".The object of research – end mills made of high-speed steel R6M5 with different angles of inclination of the screw chip groove in 20°, 30°, 45° and an end mill with a wavy cutting edge.
The subject of the study is the influence on the size of the riveted layer after processing by milling steel 40X.
Goal. Investigate the size of the riveted layer when processing 40X steel with high-speed steel end mills with different angles of inclination of the screw groove, identify a smaller size of the riveted layer, determine the design and geometry of the end mills to improve the quality of processing 40X steel.
Relevance. The topic of the dissertation is relevant for the production of prefabricated tool cases at the company "PC MION"
SCIAMACHY: The new Level 0-1 Processor
SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) is a scanning nadir and limb spectrometer covering the wavelength range from 212 nm to 2386 nm in 8 channels. It is a joint project of Germany, the Netherlands and Belgium and was launched in February 2002 on the ENVISAT platform. After the platform failure in April 2012, SCIAMACHY is now in the postprocessing phase F. SCIAMACHY�s originally specified in-orbit lifetime was double the planned lifetime. SCIAMACHY was designed to measure column densities and vertical profiles of trace gas species in the mesosphere, in the stratosphere and in the troposphere (Bovensmann et al., 1999). It can detect a large amount of atmospheric gases (e.g. O3 , H2CO, CHOCHO, SO2 , BrO, OClO, NO2 , H2O, CO, CH4 , among others ) and can provide information about aerosols and clouds.
The operational processing of SCIAMACHY is split into Level 0-1 processing (essentially providing calibrated radiances) and Level 1-2 processing providing geophysical products.
The operational Level 0-1 processor has been completely re-coded and embedded in a newly developed framework that speeds up processing considerably. In the frame of the SCIAMACHY Quality Working Group activities, ESA is continuing the improvement of the archived data sets. Currently Version 9 of the Level 0-1 processor is being implemented. It will include
An updated degradation correction
Several improvements in the SWIR spectral range like a better dark correction, an improved dead & bad pixel characterisation and an improved spectral calibration
Improvements to the polarisation correction algorithm
Improvements to the geolocation by a better pointing characterisation
Additionally a new format for the Level 1b and Level 1c will be implemented. The version 9 products will be available in netCDF version 4 that is aligned with the formats of the GOME -1 and Sentinel missions. We will present the first results of the new Level 0-1 processing in this paper
ESA's Space-based Doppler Wind Lidar Mission Aeolus - First Wind and Aerosol Product Assessment Results
The European Space Agency (ESA) wind mission,
Aeolus, hosts the first space-based Doppler Wind
Lidar (DWL) world-wide. The primary mission
objective is to demonstrate the DWL technique for
measuring wind profiles from space, intended for
assimilation in Numerical Weather Prediction
(NWP) models. The wind observations will also be
used to advance atmospheric dynamics research
and for evaluation of climate models. Mission spinoff products are profiles of cloud and aerosol
optical properties. Aeolus was launched on 22
August 2018, and the Atmospheric LAser Doppler
INstrument (Aladin) instrument switch-on was
completed with first high energy output in wind
mode on 4 September 2018. The on-ground
data processing facility worked excellent, allowing
L2 product output in near-real-time from the start
of the mission. First results from the wind profile
product (L2B) assessment show that the winds are
of very high quality, with random errors in the free
Troposphere within (cloud/aerosol backscatter
winds: 2.1 m/s) and larger (molecular backscatter
winds: 4.3 m/s) than the requirements (2.5 m/s), but
still allowing significant positive impact in first
preliminary NWP impact experiments. The higher
than expected random errors at the time of writing
are amongst others due to a lower instrument outand input photon budget than designed. The
instrument calibration is working well, and some of
the data processing steps are currently being
refined to allow to fully correct instrument
alignment related drifts and elevated detector dark
currents causing biases in the first data product
version. The optical properties spin-off product
(L2A) is being compared e.g. to NWP model
clouds, air quality model forecasts, and collocated
ground-based observations. Features including
optically thick and thin particle and hydrometeor
layers are clearly identified and are being validated
Initial Assessment of the Performance of the First Wind Lidar in Space on Aeolus
Soon after its successful launch in August 2018,
the spaceborne wind lidar ALADIN (Atmospheric
LAser Doppler INstrument) on-board ESA's
Earth Explorer satellite Aeolus has demonstrated
to provide atmospheric wind profiles on a global
scale. Being the first ever Doppler Wind Lidar
(DWL) instrument in space, ALADIN contributes
to the improvement in numerical weather
prediction (NWP) by measuring one component
of the horizontal wind vector. The performance of
the ALADIN instrument was assessed by a team
from ESA, DLR, industry, and NWP centers
during the first months of operation. The current
knowledge about the main contributors to the
random and systematic errors from the instrument
will be discussed. First validation results from an
airborne campaign with two wind lidars on-board
the DLR Falcon aircraft will be shown
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