23,742 research outputs found
Power Beacon-Assisted Millimeter Wave Ad Hoc Networks
Deployment of low cost power beacons (PBs) is a promising solution for
dedicated wireless power transfer (WPT) in future wireless networks. In this
paper, we present a tractable model for PB-assisted millimeter wave (mmWave)
wireless ad hoc networks, where each transmitter (TX) harvests energy from all
PBs and then uses the harvested energy to transmit information to its desired
receiver. Our model accounts for realistic aspects of WPT and mmWave
transmissions, such as power circuit activation threshold, allowed maximum
harvested power, maximum transmit power, beamforming and blockage. Using
stochastic geometry, we obtain the Laplace transform of the aggregate received
power at the TX to calculate the power coverage probability. We approximate and
discretize the transmit power of each TX into a finite number of discrete power
levels in log scale to compute the channel and total coverage probability. We
compare our analytical predictions to simulations and observe good accuracy.
The proposed model allows insights into effect of system parameters, such as
transmit power of PBs, PB density, main lobe beam-width and power circuit
activation threshold on the overall coverage probability. The results confirm
that it is feasible and safe to power TXs in a mmWave ad hoc network using PBs.Comment: This work has been submitted to the IEEE for possible publication.
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Stochastic Averaging Principle for Dynamical Systems with Fractional Brownian Motion
Stochastic averaging for a class of stochastic differential equations (SDEs)
with fractional Brownian motion, of the Hurst parameter H in the interval (1/2,
1), is investigated. An averaged SDE for the original SDE is proposed, and
their solutions are quantitatively compared. It is shown that the solution of
the averaged SDE converges to that of the original SDE in the sense of mean
square and also in probability. It is further demonstrated that a similar
averaging principle holds for SDEs under stochastic integral of pathwise
backward and forward types. Two examples are presented and numerical
simulations are carried out to illustrate the averaging principle
Doctor of Philosophy
dissertationIliad is a diagnostic expert system for internal medicine. One important feature that Iliad offers is the ability to analyze a particular patient case and to determine the most cost-effective findings to pursue next at any stage of a work-up. The best information"" algorithm combines an information content calculation together with a cost factor. The calculations then provide a rank-ordering of the alternative patient findings according to cost-effectiveness. This dissertation presents a three-part study to evaluate the performance of different best information algorithms. In the first two parts of the study the suggestions about the next best data elements to pursue from different algorithms were collected for different vignettes. The performance of different algorithms was compared based on the judgments provided by expert clinicians. The results indicated that the current Iliad information content model could be improved by using a version of Shannon information content model. The third part of the study evaluated different best information algorithms by a simulation approach. The results indicated that two types of diagnostic behaviors could be simulated. The first type of behavior was characterized by pursuing more history and physical examination findings, less laboratory tests, less expensive work-ups, and more steps to solve a patient case. The second type of behavior was characterized by pursuing less history and physical examination findings, more laboratory tests, more expensive work-ups, and less steps to solve a patient case. The Shannon information content model accomplished work-ups that were significantly less costly than work-ups performed by the current LR (likelihood ratio) information content model. However, the Shannon model required additional computational resources and more history and physical examination steps than the LR model. Decisions regarding the implementation of alternative models require a balance of the relative merits of cost, steps, expert preference, and other important factors."
Asymmetries and Violation in Charmed Baryon Decays into Neutral Kaons
We study the asymmetries and violations in charm-baryon
decays with neutral kaons in the final state. The asymmetry can
be used to search for two-body doubly Cabibbo-suppressed amplitudes of
charm-baryon decays, with the one in as a promising
observable. Besides, it is studied for a new -violation effect in these
processes, induced by the interference between the Cabibbo-favored and doubly
Cabibbo-suppressed amplitudes with the neutral kaon mixing. Once the new
CP-violation effect is determined by experiments, the direct asymmetry in
neutral kaon modes can then be extracted and used to search for new physics.
The numerical results based on symmetry will be tested by the
experiments in the future.Comment: 15 pages, 3 tables. Version published in JHE
Domain wall brane in a reduced Born-Infeld- theory
The Born-Infeld theory is reduced from the Born-Infeld determinantal
gravity in Weitzenb\"ock spacetime. We investigate a braneworld scenario in
this theory and obtain an analytic domain wall solution by utilizing the
first-order formalism. The model is stable against the linear tensor
perturbation. It is shown that the massless graviton is localized on the brane,
but the continuous massive gravitons are non-localized and will generate a tiny
correction with the behavior of to the Newtonian potential.
The four-dimensional teleparallel gravity is recovered as an effective infrared
theory on the brane. As a physical application, we consider the
(quasi-)localization property of spin-1/2 Dirac fermion in this model.Comment: 9 pages, 2 figures, published versio
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