25,267 research outputs found
A Novel Framework for Software Defined Wireless Body Area Network
Software Defined Networking (SDN) has gained huge popularity in replacing
traditional network by offering flexible and dynamic network management. It has
drawn significant attention of the researchers from both academia and
industries. Particularly, incorporating SDN in Wireless Body Area Network
(WBAN) applications indicates promising benefits in terms of dealing with
challenges like traffic management, authentication, energy efficiency etc.
while enhancing administrative control. This paper presents a novel framework
for Software Defined WBAN (SDWBAN), which brings the concept of SDN technology
into WBAN applications. By decoupling the control plane from data plane and
having more programmatic control would assist to overcome the current lacking
and challenges of WBAN. Therefore, we provide a conceptual framework for SDWBAN
with packet flow model and a future direction of research pertaining to SDWBAN.Comment: Presented on 8th International Conference on Intelligent Systems,
Modelling and Simulatio
DNA folding and melting observed in real time redefine the energy landscape
We report real-time observations of the folding and melting of DNA by probing two active sites of a hairpin structure, the bases and the stem end, and using an ultrafast T-jump. Studies at different initial temperatures (before, during, and after melting) provide the time scale of water heating (<20 ps), single-strand destacking (700 ps to 2 ns), and hairpin destacking (microseconds and longer) in solutions of various ionic strengths and pH values. The behavior of transient changes gives direct evidence to the existence of intermediate collapsed structures, labile in destacking but compact in nature, and indicates that melting is not a two-state process. We propose a landscape that is defined by these nucleation structures and destacking for efficient folding and melting
Regularization of Vertical-Cavity Surface-Emitting Lasers emission by periodic non-Hermitian potentials
We propose a novel physical mechanism based on periodic non-Hermitian
potentials to efficiently control the complex spatial dynamics of broad-area
lasers, particularly in Vertical-Cavity Surface-Emitting Lasers (VCSELs),
achieving a stable emission of maximum brightness. Radially dephased periodic
refractive index and gain-loss modulations accumulate the generated light from
the entire active layer and concentrate it around the structure axis to emit
narrow, bright beams. The effect is due to asymmetric-inward radial coupling
between transverse modes, for particular phase differences of the refractive
index and gain-loss modulations. Light is confined into a central beam with
large intensity opening the path to design compact, bright and efficient
broad-area light sources. We perform a comprehensive analysis to explore the
maximum central intensity enhancement and concentration regimes. The study
reveals that the optimum schemes are those holding unidirectional inward
coupling but not fulfilling a perfect local PT-symmetry.Comment: 4 pages, 4 figure
Supergravity inflation on a brane
We discuss supergravity inflation in braneworld cosmology for the class of
potentials with .
These minimal SUGRA models evade the problem due to a broken shift
symmetry and can easily accommodate the observational constraints. Models with
smaller are preferred while models with larger are out of the
region. Remarkably, the field excursions required for -foldings stay
sub-planckian .Comment: 10 pages, 4 figure
X-ray Absorption Near Edge Structure of FePt nanoclusters
X-ray Absorption Near Edge Structure [XANES] of FePt nanoclusters has been
studied using a full multiple scattering, self-consistent field [SCF],
real-space Green`s function approach realized via the powerful ab initio FEFF8
code. One purpose of our study is to determine the sensitivity of Pt L3 edge
with respect to the size and shape of the FePt nanoclusters. We also give the
results of the calculations with respect to the Fe L3 edge. Calculations are
made with and without core-hole for two main reasons, to check and cross-check
the FEFF code and also since in some cases it is known such as Pt clusters that
better results are obtained without the core-hole. This is mainly because the
screening electron will occupy empty d or f states and correspondingly reduce
the white line intensity.Comment: TeX version 3.14159, LaTex2e, 6 pages with 6 figure
Near-infrared photoluminescence from molecular crystals containing tellurium
We report the observation of near-infrared photoluminescence from
Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 molecular crystals containing Te42+ polycations.
The experimental and theoretical results clearly revealed that Te42+ polycation
is one smart near-infrared emitter with characteristic emission peaks at 1252
and 1258 nm for Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 crystals, respectively, resulting
from the intrinsic electronic transitions of Te42+. Furthermore, it was also
found that the emissions strongly depend on the excitation wavelengths for both
Te4(Ga2Cl7)2 and Te4(Al2Cl7)2 samples, most possibly owing to the co-existence
of other Te-related optically active centers. This research not only enriches
the species of luminescent charged p-block element polyhedra and deepens the
understanding of Te-related photophysical behaviors, but also may stimulate
efforts for designing novel material systems using such active centers. It is
also greatly expected that these sub-nanometer optically active species could
exist in other systems such as glasses, polymers, and bulk optical crystals,
and the stabilization of these centers in widely used hosts will pave the way
for their practical applications
Formal Availability Analysis using Theorem Proving
Availability analysis is used to assess the possible failures and their
restoration process for a given system. This analysis involves the calculation
of instantaneous and steady-state availabilities of the individual system
components and the usage of this information along with the commonly used
availability modeling techniques, such as Availability Block Diagrams (ABD) and
Fault Trees (FTs) to determine the system-level availability. Traditionally,
availability analyses are conducted using paper-and-pencil methods and
simulation tools but they cannot ascertain absolute correctness due to their
inaccuracy limitations. As a complementary approach, we propose to use the
higher-order-logic theorem prover HOL4 to conduct the availability analysis of
safety-critical systems. For this purpose, we present a higher-order-logic
formalization of instantaneous and steady-state availability, ABD
configurations and generic unavailability FT gates. For illustration purposes,
these formalizations are utilized to conduct formal availability analysis of a
satellite solar array, which is used as the main source of power for the Dong
Fang Hong-3 (DFH-3) satellite.Comment: 16 pages. arXiv admin note: text overlap with arXiv:1505.0264
The Impact of Exchange Rate Depreciation on Economic and Business Growth in Pakistan
Depreciation remained a common factor in Pakistani economic history in different regimes, which affected different economic variables, especially the growth and business sector. We have linked depreciation with economic and business growth for Pakistan in this paper. Using time series data from 1976 to 2010 and employing cointegration followed by the Error Correction Model, we find that exchange rate depreciation has adversely affected growth in the business sector, notably Investment and FDI, while net export has a positive association with the exchange rate. All these findings reveal that depreciation is not a good practice because it has negative impact for growth in the business sector. The present scenario of the flexible exchange rate doesn't allow the corresponding authorities to set desirable exchange rates, however, the government must reinforce the real sector in order to ensure a stable exchange rate and hence macroeconomic stability. Keywords: Foreign Exchange; General; Open Economy Macroeconomics; Economic Growth of Open Economie
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