5,212 research outputs found
An Android-Based Mechanism for Energy Efficient Localization Depending on Indoor/Outdoor Context
Today, there is widespread use of mobile applications that take advantage of a user\u27s location. Popular usages of location information include geotagging on social media websites, driver assistance and navigation, and querying nearby locations of interest. However, the average user may not realize the high energy costs of using location services (namely the GPS) or may not make smart decisions regarding when to enable or disable location services-for example, when indoors. As a result, a mechanism that can make these decisions on the user\u27s behalf can significantly improve a smartphone\u27s battery life. In this paper, we present an energy consumption analysis of the localization methods available on modern Android smartphones and propose the addition of an indoor localization mechanism that can be triggered depending on whether a user is detected to be indoors or outdoors. Based on our energy analysis and implementation of our proposed system, we provide experimental results-monitoring battery life over time-and show that an indoor localization method triggered by indoor or outdoor context can improve smartphone battery life and, potentially, location accuracy
The changing role of gold in the International Monetary System
Special issue on goldGold standard ; International finance ; Gold reserves
Central bank policy towards inflation
Inflation (Finance) ; Monetary theory ; Pacific Area ; Banks and banking, Central
Stressed olympians set for a break: medalists eyeing rest and family time after the strains of competing
Dielectric Screening by 2D Substrates
Two-dimensional (2D) materials are increasingly being used as active
components in nanoscale devices. Many interesting properties of 2D materials
stem from the reduced and highly non-local electronic screening in two
dimensions. While electronic screening within 2D materials has been studied
extensively, the question still remains of how 2D substrates screen charge
perturbations or electronic excitations adjacent to them. Thickness-dependent
dielectric screening properties have recently been studied using electrostatic
force microscopy (EFM) experiments. However, it was suggested that some of the
thickness-dependent trends were due to extrinsic effects. Similarly, Kelvin
probe measurements (KPM) indicate that charge fluctuations are reduced when BN
slabs are placed on SiO, but it is unclear if this effect is due to
intrinsic screening from BN. In this work, we use first principles calculations
to study the fully non-local dielectric screening properties of 2D material
substrates. Our simulations give results in good qualitative agreement with
those from EFM experiments, for hexagonal boron nitride (BN), graphene and
MoS, indicating that the experimentally observed thickness-dependent
screening effects are intrinsic to the 2D materials. We further investigate
explicitly the role of BN in lowering charge potential fluctuations arising
from charge impurities on an underlying SiO substrate, as observed in the
KPM experiments. 2D material substrates can also dramatically change the
HOMO-LUMO gaps of adsorbates, especially for small molecules, such as benzene.
We propose a reliable and very quick method to predict the HOMO-LUMO gap of
small physisorbed molecules on 2D and 3D substrates, using only the band gap of
the substrate and the gas phase gap of the molecule.Comment: 24 pages, 5 figures, Supplementary Informatio
- …