167 research outputs found
Realistic Modeling of Human Timings for Wearable Cognitive Assistance
Wearable Cognitive Assistance (WCA) applications present a challenge to
benchmark and characterize due to their human-in-the-loop nature. Employing
user testing to optimize system parameters is generally not feasible, given the
scope of the problem and the number of observations needed to detect small but
important effects in controlled experiments. Considering the intended
mass-scale deployment of WCA applications in the future, there exists a need
for tools enabling human-independent benchmarking.
We present in this paper the first model for the complete end-to-end
emulation of humans in WCA. We build this model through statistical analysis of
data collected from previous work in this field, and demonstrate its utility by
studying application task durations. Compared to first-order approximations,
our model shows a ~36% larger gap between step execution times at high system
impairment versus low. We further introduce a novel framework for stochastic
optimization of resource consumption-responsiveness tradeoffs in WCA, and show
that by combining this framework with our realistic model of human behavior,
significant reductions of up to 50% in number processed frame samples and 20%
in energy consumption can be achieved with respect to the state-of-the-art.Comment: 16 total pages. 12 figures, 2 tables, 1 appendix. Main document body
by Manuel Olgu\'in Mu\~noz and Vishnu N. Moothedath; appendix by Vishu N.
Moothedath and Jaya Prakash Champati; editing and feedback by all authors;
funding by James Gross and Mahadev Satyanarayanan. Submitted to IEEE
Transactions on Mobile Computin
On the Origin of the -4.4 eV Band in CdTe(100)"
We calculate the bulk- (infinite system), (100)-bulk-projected- and
(100)-Surface-projected Green's functions using the Surface Green's Function
Matching method (SGFM) and an empirical tight-binding hamiltonian with
tight-binding parameters (TBP) that describe well the bulk band structure of
CdTe. In particular, we analyze the band (B--4) arising at --4.4 eV from the
top of the valence band at according to the results of Niles and
H\"ochst and at -4.6 eV according to Gawlik {\it et al.} both obtained by
Angle-resolved photoelectron spectroscopy (ARPES). We give the first
theoretical description of this band.Comment: 17 pages, Rev-TEX, CIEA-Phys. 02/9
New evidence for an early settlement of the Yucatán Peninsula, Mexico: The Chan Hol 3 woman and her meaning for the Peopling of the Americas.
Human presence on the Yucatán Peninsula reaches back to the Late Pleistocene. Osteological evidence comes from submerged caves and sinkholes (cenotes) near Tulum in the Mexican state of Quintana Roo. Here we report on a new skeleton discovered by us in the Chan Hol underwater cave, dating to a minimum age of 9.9±0.1 ky BP based on 230Th/U-dating of flowstone overlying and encrusting human phalanges. This is the third Paleoindian human skeleton with mesocephalic cranial characteristics documented by us in the cave, of which a male individual named Chan Hol 2 described recently is one of the oldest human skeletons found on the American continent. The new discovery emphasizes the importance of the Chan Hol cave and other systems in the Tulum area for understanding the early peopling of the Americas. The new individual, here named Chan Hol 3, is a woman of about 30 years of age with three cranial traumas. There is also evidence for a possible trepanomal bacterial disease that caused severe alteration of the posterior parietal and occipital bones of the cranium. This is the first time that the presence of such disease is reported in a Paleoindian skeleton in the Americas. All ten early skeletons found so far in the submerged caves from the Yucatán Peninsula have mesocephalic cranial morphology, different to the dolicocephalic morphology for Paleoindians from Central Mexico with equivalent dates. This supports the presence of two morphologically different Paleoindian populations for Mexico, coexisting in different geographical areas during the Late Pleistocene-Early Holocene
Robust modeling of human contact networks across different scales and proximity-sensing techniques
The problem of mapping human close-range proximity networks has been tackled
using a variety of technical approaches. Wearable electronic devices, in
particular, have proven to be particularly successful in a variety of settings
relevant for research in social science, complex networks and infectious
diseases dynamics. Each device and technology used for proximity sensing (e.g.,
RFIDs, Bluetooth, low-power radio or infrared communication, etc.) comes with
specific biases on the close-range relations it records. Hence it is important
to assess which statistical features of the empirical proximity networks are
robust across different measurement techniques, and which modeling frameworks
generalize well across empirical data. Here we compare time-resolved proximity
networks recorded in different experimental settings and show that some
important statistical features are robust across all settings considered. The
observed universality calls for a simplified modeling approach. We show that
one such simple model is indeed able to reproduce the main statistical
distributions characterizing the empirical temporal networks
First release of the IPHAS catalogue of new extended planetary nebulae
Date of Acceptance: 30/06/2014We present the first results of our search for new, extended planetary nebulae (PNe) based on careful, systematic, visual scrutiny of the imaging data from the Isaac Newton Telescope Photometric Ha Survey of the Northern Galactic plane (IPHAS). The newly uncovered PNe will help to improve the census of this important population of Galactic objects that serve as key windows into the late-stage evolution of low- to intermediate-mass stars. They will also facilitate study of the faint end of the ensemble Galactic PN luminosity function. The sensitivity and coverage of IPHAS allows PNe to be found in regions of greater extinction in the Galactic plane and/or those PNe in a more advanced evolutionary state and at larger distances compared to the general Galactic PN population. Using a set of newly revised optical diagnostic diagrams in combination with access to a powerful, new, multiwavelength imaging data base, we have identified 159 true, likely and possible PNe for this first catalogue release. The ability of IPHAS to unveil PNe at low Galactic latitudes and towards the Galactic Anticentre, compared to previous surveys, makes this survey an ideal tool to contribute to the improvement of our knowledge of the whole Galactic PN population.Peer reviewe
Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent
This study investigated the removal of nitrogen and phosphorus from the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) by means of a lab-scale photobioreactor in which algae biomass was cultured in a semi-continuous mode for a period of 42 days. Solids retention time was 2 days and a stable pH value in the system was maintained by adding CO2. Nitrogen and phosphorus concentrations in the SAnMBR effluent fluctuated according to the operating performance of the bioreactor and the properties of its actual wastewater load. Despite these variations, the anaerobic effluent proved to be a suitable growth medium for microalgae (mean biomass productivity was 234 mgl(-1) d(-1)), achieving a nutrient removal efficiency of 67.2% for ammonium (NH4+-N) and 97.8% for phosphate (PO4-3-P). When conditions were optimum, excellent water quality with very low ammonium and phosphate concentrations was obtained.This research project has been supported by the Spanish Research Foundation (CICYT, projects CTM2011-28595-C02-01 and CTM2011-28595-C02-02), whose support is gratefully acknowledged.Ruiz MartĂnez, A.; Martin Garcia, N.; Romero Gil, I.; Seco, A.; Ferrer, J. (2012). Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent. Bioresource Technology. 126:247-253. https://doi.org/10.1016/j.biortech.2012.09.022S24725312
Resilience of willows (<i>Salix</i> spp.) differs between families during and after flooding according to floodwater depth
Although the morphological and physiological responses of willows to flooding have already been characterized, less is known about their responses during the post- flooding period. After the end of the stress episode, plants may modify some leaf and plant traits to compensate for biomass loss. The aim of this work was to analyze the post-flooding responses of different willow genotypes under two different depths of floodwater. The hypothesis was that the growth recovery in the post-flooding period would be different according to the genotype and the floodwater depth. We analyzed three genotypes of five willow families (4 interspecific hybrids and one open-pollinated family). The treatments were: 1) Control: plants watered to field capacity; 2) T10: water covering 10 cm above soil level; 3) T65: water covering 65 cm above soil level. Both flooding treatments were followed by a period of recovery (without flooding). Growth was reduced by flooding in T65 but not in T10, while root-to-shoot ratio was reduced in both flooding treatments. The relative growth rate in height, leaf nitrogen concentration, stomatal conductance and electron transport rate changed in a different manner during the post-flooding period, depending on the treatment and genetic background. These results emphasize the need for evaluating a post - flooding recovery period for the breeding of willow genotypes destined for areas under risk of flooding. According to our results, Salix matsudana could be a source of flooding tolerance for willow breeding programs.Instituto de FisiologĂa Vegeta
Optical studies of gap, hopping energies and the Anderson-Hubbard parameter in the zigzag-chain compound SrCuO2
We have investigated the electronic structure of the zigzag ladder (chain)
compound SrCuO2 combining polarized optical absorption, reflection,
photoreflectance and pseudo-dielectric function measurements with the model
calculations. These measurements yield an energy gap of 1.42 eV (1.77 eV) at
300 K along (perpendicular) to the Cu-O chains. We have found that the lowest
energy gap, the correlation gap, is temperature independent. The electronic
structure of this oxide is calculated using both the
local-spin-density-approximation with gradient correction method, and the
tight-binding theory for the correlated electrons. The calculated density of
electronic states for non-correlated and correlated electrons shows
quasi-one-dimensional character. The correlation gap values of 1.42 eV
(indirect transition) and 1.88 eV (direct transition) have been calculated with
the electron hopping parameters t = 0.30 eV (along a chain), t_yz = 0.12 eV
(between chains) and the Anderson-Hubbard repulsion on copper sites U= 2.0 eV.
We concluded that SrCuO_2 belongs to the correlated-gap insulators.Comment: 24 pages, 8 figures, to be published in Phys.Rev.
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