2,170 research outputs found
Biological and toxicological investigations of Chicago area navigation projects
unpublishednot peer reviewe
Failure modes and gradual degradation due to large electrical stresses in GaAs/AlGaAs heterojunction bipolar transistors
In situ determination of hydraulic conductivity and hydraulic head in shallow coastal sediments
First record of the leptonectid ichthyosaur Eurhinosaurus longirostris from the Early Jurassic of Switzerland and its stratigraphic framework
An incomplete skull of the leptonectid ichthyosaur Eurhinosaurus longirostris found in the Rietheim Member (previously "Posidonienschiefer”; Toarcian, Early Jurassic) of Staffelegg, Canton Aargau, is the first record from Switzerland of this taxon and supports the status of Eurhinosaurus longirostris as a palaeobiogeographic very widespread ichthyosaur species in the Early Toarcian of Western Europe. Being from either the Bifrons or Variabilis zone, it is one of the youngest records of Eurhinosaurus and one of the few diagnostic ichthyosaur finds from this time interval. The partial skull is well articulated and preserved three-dimensionally in a carbonate concretion. Both the mode of preservation of the ichthyosaur and an associated ammonoid (Catacoeloceras raquinianum) provided the age of the concretion, which had been collected from scree. Taphocoenosis and taphonomy show the C. raquinianum to be one of few non re-worked fossils recorded from the Early to Late Toarcian boundary (Bifrons/Variabilis zone) of northern Switzerland in general and of this ammonite species in particular. The Toarcian section at Staffelegg differs from other localities where strata of the same age are exposed with respect to facies variations of the Rietheim Member (previously "Posidonienschiefer”, Early Toarcian) and the extraordinarily high thickness of the Gross Wolf Member (previously "Jurensis-Mergel”, Late Toarcian
Überörtliche Biotopverbundplanungen : eine planerische Grundlage für den Straßenbau
Anhand von drei OU im Zuge von Bundesstraßen wird dargestellt, wie die überörtliche Biotopverbundplanung dazu beitragen kann, Eingriffe nicht nur punktuell-lokal, sondern im größeren Zusammenhang der Biotopverbundsysteme zu bewerten und zu bewältigen. Die Biotopverbundplanung stellt einen Ideen- und Flächenpool bereit, Maßnahmen aus nicht ausgleichbaren Eingriffen sinnvoll zu konzentrieren und mit bestmöglicher Wirkung für Natur und Landschaft umzusetzen. Die Straßenbauverwaltung greift die Vorschläge der Biotopverbundplanung gern auf, wie weitere, bereits realisierte Vorhaben zeigen. Allerdings darf man nicht übersehen, dass Kompensationsmaßnahmen für Eingriffe an anderer Stelle bestenfalls dazu beitragen, die Qualität der Biotopverbundsysteme auf dem gegenwärtigen Stand zu erhalten
Temporal Smoothing for Joint Probabilistic People Detection in a Depth Sensor Network
Wide-area indoor people detection in a network of depth sensors is the basis for many applications, e.g. people counting or customer behavior analysis. Existing probabilistic methods use approximative stochastic inference to estimate the marginal probability distribution of people present in the scene for a single time step. In this work we investigate how the temporal context, given by a time series of multi-view depth observations, can be exploited to regularize a mean-field variational inference optimization process. We present a probabilistic grid based dynamic model and deduce the corresponding mean-field update regulations to effectively approximate the joint probability distribution of people present in the scene across space and time. Our experiments show that the proposed temporal regularization leads to a more robust estimation of the desired probability distribution and increases the detection performance
Joint Probabilistic People Detection in Overlapping Depth Images
Privacy-preserving high-quality people detection is a vital computer vision task for various indoor scenarios, e.g. people counting, customer behavior analysis, ambient assisted living or smart homes. In this work a novel approach for people detection in multiple overlapping depth images is proposed. We present a probabilistic framework utilizing a generative scene model to jointly exploit the multi-view image evidence, allowing us to detect people from arbitrary viewpoints. Our approach makes use of mean-field variational inference to not only estimate the maximum a posteriori (MAP) state but to also approximate the posterior probability distribution of people present in the scene. Evaluation shows state-of-the-art results on a novel data set for indoor people detection and tracking in depth images from the top-view with high perspective distortions. Furthermore it can be demonstrated that our approach (compared to the the mono-view setup) successfully exploits the multi-view image evidence and robustly converges in only a few iterations
Pulsed Quantum Frequency Combs from an Actively Mode-locked Intra-cavity Generation Scheme
We introduce an intra-cavity actively mode-locked excitation scheme for nonlinear microring resonators that removes the need for external laser excitation in the generation of pulsed two-photon frequency combs. We found a heralded anti-bunching dip of 0.245 and maximum coincidence-to-accidental ratio of 110 for the generated photon pairs
Effect of rainfall patterns on soil surface CO(2 )efflux, soil moisture, soil temperature and plant growth in a grassland ecosystem of northern Ontario, Canada: implications for climate change
BACKGROUND: The effect of rainfall patterns on soil surface CO(2 )efflux, soil moisture, soil temperature and plant growth was investigated in a grassland ecosystem of northern Ontario, Canada, where climatic change is predicted to introduce new precipitation regimes. Rain shelters were established in a fallow field consisting mainly of Trifolium hybridum L., Trifolium pratense L., and Phleum pratense L. Daytime ambient air temperatures within the shelters increased by an average of 1.9°C similar to predicted future increases in air temperatures for this region. To simulate six precipitation regimes which cover the maximum range to be expected under climate change, a portable irrigation system was designed to modify the frequency of monthly rainfall events with a constant delivery rate of water, while maintaining contemporary average precipitation volumes. Controls consisted of blocks irrigated with frequencies and total monthly precipitation consistent with the 25 year average rainfall for this location. RESULTS: Seasonal soil moisture correlated with soil surface CO(2 )efflux (R = 0.756, P < 0.001) and above ground plant biomass (R = 0.447, P = 0.029). By reducing irrigation frequency, soil surface CO(2 )efflux decreased by 80%, P < 0.001, while soil moisture content decreased by 42%, P < 0.001. CONCLUSIONS: Manipulating the number of precipitation events and inter-rainfall intervals, while maintaining monthly rainfall averages impacted CO(2 )efflux and plant growth. Even with monthly rainfall averages that are similar to contemporary monthly precipitation averages, decreasing the number of monthly rainfall events reduced soil surface CO(2 )efflux and plant growth through soil moisture deficits. Although many have speculated that climate change will increase ecosystem productivity, our results show that a reduction in the number of monthly rainfall events while maintaining monthly averages will limit carbon dynamics
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