311 research outputs found
Training a Fast Object Detector for LiDAR Range Images Using Labeled Data from Sensors with Higher Resolution
In this paper, we describe a strategy for training neural networks for object
detection in range images obtained from one type of LiDAR sensor using labeled
data from a different type of LiDAR sensor. Additionally, an efficient model
for object detection in range images for use in self-driving cars is presented.
Currently, the highest performing algorithms for object detection from LiDAR
measurements are based on neural networks. Training these networks using
supervised learning requires large annotated datasets. Therefore, most research
using neural networks for object detection from LiDAR point clouds is conducted
on a very small number of publicly available datasets. Consequently, only a
small number of sensor types are used. We use an existing annotated dataset to
train a neural network that can be used with a LiDAR sensor that has a lower
resolution than the one used for recording the annotated dataset. This is done
by simulating data from the lower resolution LiDAR sensor based on the higher
resolution dataset. Furthermore, improvements to models that use LiDAR range
images for object detection are presented. The results are validated using both
simulated sensor data and data from an actual lower resolution sensor mounted
to a research vehicle. It is shown that the model can detect objects from
360{\deg} range images in real time
The proximal map of the weighted mean absolute error
We investigate the proximal map for the weighted mean absolute error function. An algorithm for its efficient and vectorized evaluation is presented. As a demonstration, this algorithm is applied to a nonsmooth energy minimization problem.DFG
http://dx.doi.org/10.13039/501100001659Peer Reviewe
Direct to angiography suite approaches for the triage of suspected acute stroke patients: a systematic review and meta-analysis
Mechanical thrombectomy; Stroke; TriageTrombectomia mecànica; Ictus; TriatgeTrombectomía mecánica; Ictus; TriajeBackground:
Increasing evidence suggests improved time metrics leading to better clinical outcomes when stroke patients with suspected large vessel occlusion (LVO) are transferred directly to the angiography suite (DTAS) compared with cross-sectional imaging followed by transfer to the angiography suite. We performed a systematic review and meta-analysis on the efficacy and safety of DTAS approaches.
Methods:
We searched Embase, Medline, Scopus, and clinicaltrials.gov for studies comparing outcomes of DTAS and conventional triage. Eligible studies were assessed for risk of bias. We performed a random-effects meta-analysis on the differences of median door-to-groin and door-to-reperfusion times between intervention and control group. Secondary outcomes included good outcome at 90 days (modified Rankin Scale ⩽ 2) rate of symptomatic intracranial hemorrhage (sICH) and mortality within 90 days.
Results:
Eight studies (one randomized, one cluster-randomized trial and six observational studies) with 1938 patients were included. Door-to-groin and door-to-reperfusion times in the intervention group were on median 29.0 min [95% confidence interval (CI): 14.3–43.6; p < 0.001] and 32.1 min (95% CI: 15.1–49.1; p < 0.001) shorter compared with controls. Prespecified subgroup analyses for transfer (n = 1753) and mothership patients (n = 185) showed similar reductions of the door-to-groin and door-to-reperfusion times in response to the intervention. The odds of good outcome did not differ significantly between both groups but were numerically higher in the intervention group (odds ratio: 1.38, 95% CI: 0.97–1.95; p = 0.07). There was no significant difference for mortality and sICH between the groups.
Conclusion:
DTAS approaches for the triage of suspected LVO patients led to a significant reduction in door-to-groin and door-to-reperfusion times but an effect on functional outcome was not detected. The subgroup analysis showed similar results for transfer and mothership patients
The Historic Square Foot Dataset : outstanding small‐scale richness in Swiss grasslands around the year 1900
Grasslands host a significant share of Europe's species diversity but are among the most threatened vegetation types of the continent. Resurvey studies can help to understand patterns and drivers of changes in grassland diversity and species composition. However, most resurveys are based on local or regional data, and hardly reach back more than eight decades. Here, we publish and describe the Historic Square Foot Dataset, comprising 580 0.09-m2 and 43 1-m2 vegetation plots carefully sampled between 1884 and 1931, covering a wide range of grassland types across Switzerland. We provide the plots as an open-access data set with coordinates, relocation accuracy and fractional aboveground biomass per vascular plant species. We assigned EUNIS habitat types to most plots. Mean vascular plant species richness in 0.09 m2 was 19.7, with a maximum of 47. This is considerably more than the present-day world record of 43 species for this plot size. Historically, species richness did not vary with elevation, differing from the unimodal relationship found today. The data set provides unique insight into how grasslands in Central Europe looked more than 100 years ago, thus offering manifold options for studies on the development of grassland biodiversity and productivity
Strongly Correlated Quantum Fluids: Ultracold Quantum Gases, Quantum Chromodynamic Plasmas, and Holographic Duality
Strongly correlated quantum fluids are phases of matter that are
intrinsically quantum mechanical, and that do not have a simple description in
terms of weakly interacting quasi-particles. Two systems that have recently
attracted a great deal of interest are the quark-gluon plasma, a plasma of
strongly interacting quarks and gluons produced in relativistic heavy ion
collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic
gases confined in optical or magnetic traps. These systems differ by more than
20 orders of magnitude in temperature, but they were shown to exhibit very
similar hydrodynamic flow. In particular, both fluids exhibit a robustly low
shear viscosity to entropy density ratio which is characteristic of quantum
fluids described by holographic duality, a mapping from strongly correlated
quantum field theories to weakly curved higher dimensional classical gravity.
This review explores the connection between these fields, and it also serves as
an introduction to the Focus Issue of New Journal of Physics on Strongly
Correlated Quantum Fluids: from Ultracold Quantum Gases to QCD Plasmas. The
presentation is made accessible to the general physics reader and includes
discussions of the latest research developments in all three areas.Comment: 138 pages, 25 figures, review associated with New Journal of Physics
special issue "Focus on Strongly Correlated Quantum Fluids: from Ultracold
Quantum Gases to QCD Plasmas"
(http://iopscience.iop.org/1367-2630/focus/Focus%20on%20Strongly%20Correlated%20Quantum%20Fluids%20-%20from%20Ultracold%20Quantum%20Gases%20to%20QCD%20Plasmas
Direct to angiography suite approaches for the triage of suspected acute stroke patients: a systematic review and meta-analysis
Increasing evidence suggests improved time metrics leading to better clinical outcomes when stroke patients with suspected large vessel occlusion (LVO) are transferred directly to the angiography suite (DTAS) compared with cross-sectional imaging followed by transfer to the angiography suite. We performed a systematic review and meta-analysis on the efficacy and safety of DTAS approaches.; We searched Embase, Medline, Scopus, and clinicaltrials.gov for studies comparing outcomes of DTAS and conventional triage. Eligible studies were assessed for risk of bias. We performed a random-effects meta-analysis on the differences of median door-to-groin and door-to-reperfusion times between intervention and control group. Secondary outcomes included good outcome at 90 days (modified Rankin Scale ⩽ 2) rate of symptomatic intracranial hemorrhage (sICH) and mortality within 90 days.; Eight studies (one randomized, one cluster-randomized trial and six observational studies) with 1938 patients were included. Door-to-groin and door-to-reperfusion times in the intervention group were on median 29.0 min [95% confidence interval (CI): 14.3-43.6;; p; < 0.001] and 32.1 min (95% CI: 15.1-49.1;; p; < 0.001) shorter compared with controls. Prespecified subgroup analyses for transfer (; n; = 1753) and mothership patients (; n; = 185) showed similar reductions of the door-to-groin and door-to-reperfusion times in response to the intervention. The odds of good outcome did not differ significantly between both groups but were numerically higher in the intervention group (odds ratio: 1.38, 95% CI: 0.97-1.95;; p; = 0.07). There was no significant difference for mortality and sICH between the groups.; DTAS approaches for the triage of suspected LVO patients led to a significant reduction in door-to-groin and door-to-reperfusion times but an effect on functional outcome was not detected. The subgroup analysis showed similar results for transfer and mothership patients.; Registration:; This study was registered in PROSPERO (CRD42020213621)
Quark Soup al dente: Applied Superstring Theory
We discuss the application of the AdS/CFT correspondence to possibly gain new
physical insights for the strongly coupled quark-gluon plasma. This article
provides an informal summary of a talk given by RCM at the 18th International
Conference on General Relativity and Gravitation in July 2007.Comment: This article provides an informal summary of a talk given by RCM at
the 18th International Conference on General Relativity and Gravitation in
July 200
Design and performance of the multiplexing spectrometer CAMEA
The cold neutron multiplexing secondary spectrometer CAMEA (Continuous Angle
Multiple Energy Analysis) was commissioned at the Swiss spallation neutron
source SINQ at the Paul Scherrer Institut at the end of 2018. The spectrometer
is optimised for an efficient data collection in the horizontal scattering
plane, allowing for detailed and rapid mapping of excitations under extreme
conditions. The novel design consists of consecutive, upward scattering
analyzer arcs underneath an array of position sensitive detectors mounted
inside a low permeability stainless-steel vacuum vessel. The construction of
the world's first continuous angle multiple energy analysis instrument required
novel solutions to many technical challenges, including analyzer mounting,
vacuum connectors, and instrument movement. These were solved by extensive
prototype experiments and in-house developments. Here we present a technical
overview of the spectrometer describing in detail the engineering solutions and
present our first experimental data taken during the commissioning. Our results
demonstrate the tremendous gains in data collection rate for this novel type of
spectrometer design
Indikatoren zur Erfassung genetischer Vielfalt in biologischen und nicht-biologischen Landwirtschaftssystemen
Genetic variability is the fundament of life. Large genetic variability within species is the basis for adaptation to changing environmental conditions. Farmers and breeders have developed a multitude of crop cultivars and animal breeds to stabilize and increase quality and productivity. This study evaluated genetic diversity within different organic and non-organic farming systems using crop-cultivar and livestock-breed information as simple indicators. Data was collected using on-farm surveys in 15 case study regions in Europe and beyond. Selected indicators revealed strong differences of cultivar diversity between different countries and farming systems across Europe. No or only small differences were detectable between organic and non-organic farming systems. Landraces, as on-farm genetic resources, were under-represented in European case study regions
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