1,371 research outputs found
Hybrid Bayesian Eigenobjects: Combining Linear Subspace and Deep Network Methods for 3D Robot Vision
We introduce Hybrid Bayesian Eigenobjects (HBEOs), a novel representation for
3D objects designed to allow a robot to jointly estimate the pose, class, and
full 3D geometry of a novel object observed from a single viewpoint in a single
practical framework. By combining both linear subspace methods and deep
convolutional prediction, HBEOs efficiently learn nonlinear object
representations without directly regressing into high-dimensional space. HBEOs
also remove the onerous and generally impractical necessity of input data
voxelization prior to inference. We experimentally evaluate the suitability of
HBEOs to the challenging task of joint pose, class, and shape inference on
novel objects and show that, compared to preceding work, HBEOs offer
dramatically improved performance in all three tasks along with several orders
of magnitude faster runtime performance.Comment: To appear in the International Conference on Intelligent Robots
(IROS) - Madrid, 201
Design of waveguides and transmission lines by the distributed maximum principle
Maximum principle for distributed systems applied to design of waveguides and transmission line
Visualizing Landslide Hazards: Methods for Empowering Communities in Guatemala Through Hazard Mapping
Landslides occur at a high frequency throughout the mountainous regions of Guatemala, posing an elevated risk to communities and their infrastructure. A crucial component of the analysis of landslide hazards incorporates the creation of landslide hazard or susceptibility maps. This paper\u27s research objective had two distinct components. The first was to identify practical and effective cartographic visualization methods to deliver map-based hazard information at the community level in Guatemala. Mapping methods were evaluated for their potential effectiveness in visually communicating landslide risks to the isolated rural communities of Lake Atitlan and the town of Santiago Atitlan. The research illustrated the importance of the depiction of relief, imagery, and landmarks in addition to local knowledge of the construction of hazard maps.
The second component analyzed the suitability of SRTM 90-meter resolution DEMs for landslide susceptibility mapping. A SRTM 90-meter resolution DEM of the Sierra de las Minas, Guatemala and corresponding USGS landslide inventories were examined in the ArcMap 10 environment. Spatial analysis revealed that although lower resolution did limit the SRTM DEM\u27s suitability for comprehensive landslide hazard analysis in Guatemala, a potential existed for it to be a useful aid in identifying areas susceptible to large debris flow
The Unaka Mountains of Tennessee and North Carolina
The author examines the geography, climate, natural resources, and people of the Unaka Mountains. He also discusses transportation, tourism, and the Great Smoky Mountains National Park
Seismicity and active tectonics of the Andes and the origin of the Altiplano
Shallow and intermediate depth earthquakes and crustal movements in the Andes Mountains of Peru are discussed. Epicenters of major seismic events are shown on charts. Microearthquakes are mapped on a chart
Temperature-Time History of Subducted Continental-Crust, Mount Olympos Region, Greece
In the Mt. Olympos region of northeastern Greece, continental margin strata and basement rocks were subducted and metamorphosed under blueschist facies conditions, and thrust over carbonate platform strata during Alpine orogenesis. Subsequent exposure of the subducted basement rocks by normal faulting has allowed an integrated study of the timing of metamorphism, its relationship to deformation, and the thermal history of the subducted terrane. Alpine low-grade metamorphic assemblages occur at four structural levels. Three thrust sheets composed of Paleozoic granitic basement and Mesozoic metasedimentary cover were thrust over Mesozoic carbonate rocks and Eocene flysch; thrusting and metamorphism occurred first in the highest thrust sheets and progressed downward as units were imbricated from NE to SW. 40Ar/39Ar spectra from hornblende, white mica, and biotite samples indicate that the upper two units preserve evidence of four distinct thermal events: (1) 293–302 Ma crystallization of granites, with cooling from \u3e550°C to \u3c325°C by 284 Ma; (2) 98–100 Ma greenschist to blueschist-greenschist transition facies metamorphism (T∼350–500°C) and imbrication of continental thrust sheets; (3) 53–61 Ma blueschist facies metamorphism and deformation of the basement and continental margin units at T\u3c350–400°C; (4) 36–40 Ma thrusting of blueschists over the carbonate platform, and metamorphism at T∼200–350°C. Only the Eocene and younger events affected the lower two structural packages. A fifth event, indicated by diffusive loss profiles in microcline spectra, reflects the beginning of uplift and cooling to T\u3c100–150°C at 16–23 Ma, associated with normal faulting which continued until Quaternary time. Incomplete resetting of mica ages in all units constrains the temperature of metamorphism during continental subduction to T≤350°C, the closure temperature for Ar in muscovite. The diffusive loss profiles in micas and K-feldspars enable us to “see through” the younger events to older events in the high-T parts of the release spectra. Micas grown during earlier metamorphic events lost relatively small amounts of Ar during subsequent high pressure-low temperature metamorphism. Release spectra from phengites grown during Eocene metamorphism and deformation record the ages of the Ar-loss events. Alpine deformation in northern Greece occurred over a long time span (∼90 Ma), and involved subduction and episodic imbrication of continental basement before, during, and after the collision of the Apulian and Eurasian plates. Syn-subduction uplift and cooling probably combined with intermittently higher cooling rates during extensional events to preserve the blueschist facies mineral assemblages as they were exhumed from depths of \u3e20 km. Extension in the Olympos region was synchronous with extension in the Mesohellenic trough and the Aegean back-arc, and concurrent with westward-progressing shortening in the external Hellenides
Serum Cotinine Levels and Prehypertension in Never Smokers
Background. Few studies have shown that self-reported secondhand smoke exposure in never smokers is associated with high blood pressure. However, there are no studies investigating the relationship between secondhand smoke exposure, measured objectively by serum cotinine levels, and high blood pressure in never smokers.
Methods. We examined never smokers (n=2027) from the National Health and Nutrition Examination Survey 2005–2008. Our exposure of interest was the secondhand smoke exposure estimated by serum cotinine level and our outcome was prehypertension (n=734), defined as a systolic blood pressure of 120–139 mmHg or diastolic blood pressure of 80–89 mmHg. Results. We found that, in never smokers, serum cotinine levels were positively associated with prehypertension. Compared to those with cotinine levels in the lowest quartile (≤0.024 ng/mL), the multivariable odds ratio (95% confidence interval) of prehypertension among those with cotinine levels in the highest quartile (≥0.224 ng/mL) was 1.45(1.00, 2.11); P trend =0.0451. In subsequent subgroup analyses, the positive association was found to be stronger among men, non-Whites, and non-obese subjects. Conclusion. Higher secondhand smoke exposure measured objectively by serum cotinine levels was found to be associated with prehypertension in certain subgroups of a representative sample of the US population
Structural discordance between neogene detachments and frontal Sevier thrusts, central Mormon Mountains, southern Nevada
Detailed geologic mapping in the Mormon Mountains of southern Nevada provides significant insight into processes of extensional tectonics developed within older compressional orogens. A newly discovered, WSW-directed low-angle normal fault, the Mormon Peak detachment, juxtaposes the highest levels of the frontal most part of the east-vergent, Mesozoic Sevier thrust belt with autochthonous crystalline basement. Palinspastic analysis suggests that the detachment initially dipped 20–25° to the west and cut discordantly across thrust faults. Nearly complete lateral removal of the hanging wall from the area has exposed a 5 km thick longitudinal cross-section through the thrust belt in the footwall, while highly attenuated remnants of the hanging wall (nowhere more than a few hundred meters thick) structurally veneer the range. The present arched configuration of the detachment resulted in part from progressive “domino-style” rotation of a few degrees while it was active, but is largely due to rotation on younger, structurally lower, basement-penetrating normal faults that initiated at high-angle.
The geometry and kinematics of normal faulting in the Mormon Mountains suggest that pre-existing thrust planes are not required for the initiation of low-angle normal faults, and even where closely overlapped by extensional tectonism, need not function as a primary control of detachment geometry. Caution must thus be exercised in interpreting low-angle normal faults of uncertain tectonic heritage such as those seen in the COCORP west-central Utah and BIRP's MOIST deep-reflection profiles. Although thrust fault reactivation has reasonably been shown to be the origin of a very few low-angle normal faults, our results indicate that it may not be as fundamental a component of orogenic architecture as it is now widely perceived to be. We conclude that while in many instances thrust fault reactivation may be both a plausible and attractive hypothesis, it may never be assumed
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