2,294 research outputs found
Attack-Aware Routing and Wavelength Assignment of Scheduled Lightpath Demands
In Transparent Optical Networks, tra c is carried over lightpaths, creating a vir- tual topology over the physical connections of optical bers. Due to the increasingly high data rates and the vulnerabilities related to the transparency of optical network, security issues in transparent wavelength division multiplexing (WDM) optical net- works have become of great signi cance to network managers. In this thesis, we intro- duce some basic concepts of transparent optical network, the types and circumstances of physical-layer attacks and analysis of related work at rst. In addition, based on the previous researches, we present a novel approach and several new objective cri- terions for the problem of attack-aware routing and wavelength assignment. Integer Linear Programming (ILP) formulation is used to solve the routing sub-problem with the objective to minimize the disruption of physical-layer attack as well as to opti- mize Routing and Wavelength Assignment (RWA) of scheduled transparent optical network
Linear stability analysis of transient electrodeposition in charged porous media: suppression of dendritic growth by surface conduction
We study the linear stability of transient electrodeposition in a charged
random porous medium, whose pore surface charges can be of any sign, flanked by
a pair of planar metal electrodes. Discretization of the linear stability
problem results in a generalized eigenvalue problem for the dispersion relation
that is solved numerically, which agrees well with the analytical approximation
obtained from a boundary layer analysis valid at high wavenumbers. Under
galvanostatic conditions in which an overlimiting current is applied, in the
classical case of zero surface charges, the electric field at the cathode
diverges at Sand's time due to electrolyte depletion. The same phenomenon
happens for positive charges but earlier than Sand's time. However, negative
charges allow the system to sustain an overlimiting current via surface
conduction past Sand's time, keeping the electric field bounded. Therefore, at
Sand's time, negative charges greatly reduce surface instabilities and suppress
dendritic growth, while zero and positive charges magnify them. We compare
theoretical predictions for overall surface stabilization with published
experimental data for copper electrodeposition in cellulose nitrate membranes
and demonstrate good agreement between theory and experiment. We also apply the
stability analysis to how crystal grain size varies with duty cycle during
pulse electroplating.Comment: 55 pages, 12 figures, 2 table
Short-coherence length superconductivity in the Attractive Hubbard Model in three dimensions
We study the normal state and the superconducting transition in the
Attractive Hubbard Model in three dimensions, using self-consistent
diagrammatics. Our results for the self-consistent -matrix approximation are
consistent with 3D-XY power-law critical scaling and finite-size scaling. This
is in contrast to the exponential 2D-XY scaling the method was able to capture
in our previous 2D calculation. We find the 3D transition temperature at
quarter-filling and to be . The 3D critical regime is much
narrower than in 2D and the ratio of the mean-field transition to is
about 5 times smaller than in 2D. We also find that, for the parameters we
consider, the pseudogap regime in 3D (as in 2D) coincides with the critical
scaling regime.Comment: 4 pages, 5 figure
Quantitative calculations of the excitonic energy spectra of semiconducting single-walled carbon nanotubes within a -electron model
Using Coulomb correlation parameters appropriate for -conjugated
polymers (PCPs), and a nearest neighbor hopping integral that is arrived at by
fitting the energy spectra of three zigzag semiconducting single-walled carbon
nanotubes (S-SWCNTs), we are able to determine quantitatively the exciton
energies and exciton binding energies of 29 S-SWCNTs within a semiempirical
-electron Hamiltonian that has been widely used for PCPs. Our work
establishes the existence of a deep and fundamental relationship between PCPs
and S-SWCNTs.Comment: 6 pages, 2 figures, 2 table
Plane Constraints Aided Multi-Vehicle Cooperative Positioning Using Factor Graph Optimization
The development of vehicle-to-vehicle (V2V) communication facil-itates the
study of cooperative positioning (CP) techniques for vehicular applications.
The CP methods can improve the posi-tioning availability and accuracy by
inter-vehicle ranging and data exchange between vehicles. However, the
inter-vehicle rang-ing can be easily interrupted due to many factors such as
obsta-cles in-between two cars. Without inter-vehicle ranging, the other
cooperative data such as vehicle positions will be wasted, leading to
performance degradation of range-based CP methods. To fully utilize the
cooperative data and mitigate the impact of inter-vehicle ranging loss, a novel
cooperative positioning method aided by plane constraints is proposed in this
paper. The positioning results received from cooperative vehicles are used to
construct the road plane for each vehicle. The plane parameters are then
introduced into CP scheme to impose constraints on positioning solutions. The
state-of-art factor graph optimization (FGO) algo-rithm is employed to
integrate the plane constraints with raw data of Global Navigation Satellite
Systems (GNSS) as well as inter-vehicle ranging measurements. The proposed CP
method has the ability to resist the interruptions of inter-vehicle ranging
since the plane constraints are computed by just using position-related data. A
vehicle can still benefit from the position data of cooperative vehicles even
if the inter-vehicle ranging is unavaila-ble. The experimental results indicate
the superiority of the pro-posed CP method in positioning performance over the
existing methods, especially when the inter-ranging interruptions occur.Comment: 14 pages, 16 figures, IEEE trans on IT
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