40,054 research outputs found
Ground state cooling of a nanomechanical resonator in the weak-confinement regime via quantum interference
Ground state cooling of a nanomechanical resonator coupled to a
superconducting flux qubit is discussed. We show that by inducing quantum
interference to cancel detrimental carrier excitations, ground state cooling
becomes possible in the weak-confinement or non-resolved regime. The qubit is
modelled as a three-level system in lambda configuration, and the driving
fluxes are applied such that the qubit absorption spectrum exhibits
electromagnetically induced transparency, thereby cancelling the unwanted
carrier excitation. As our interference-based scheme allows to apply strong
cooling fields, fast and efficient cooling can be achieved
Generalized extreme value regression for binary response data: An application to B2B electronic payments system adoption
In the information system research, a question of particular interest is to
interpret and to predict the probability of a firm to adopt a new technology
such that market promotions are targeted to only those firms that were more
likely to adopt the technology. Typically, there exists significant difference
between the observed number of ``adopters'' and ``nonadopters,'' which is
usually coded as binary response. A critical issue involved in modeling such
binary response data is the appropriate choice of link functions in a
regression model. In this paper we introduce a new flexible skewed link
function for modeling binary response data based on the generalized extreme
value (GEV) distribution. We show how the proposed GEV links provide more
flexible and improved skewed link regression models than the existing skewed
links, especially when dealing with imbalance between the observed number of
0's and 1's in a data. The flexibility of the proposed model is illustrated
through simulated data sets and a billing data set of the electronic payments
system adoption from a Fortune 100 company in 2005.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS354 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Traffic congestion in interconnected complex networks
Traffic congestion in isolated complex networks has been investigated
extensively over the last decade. Coupled network models have recently been
developed to facilitate further understanding of real complex systems. Analysis
of traffic congestion in coupled complex networks, however, is still relatively
unexplored. In this paper, we try to explore the effect of interconnections on
traffic congestion in interconnected BA scale-free networks. We find that
assortative coupling can alleviate traffic congestion more readily than
disassortative and random coupling when the node processing capacity is
allocated based on node usage probability. Furthermore, the optimal coupling
probability can be found for assortative coupling. However, three types of
coupling preferences achieve similar traffic performance if all nodes share the
same processing capacity. We analyze interconnected Internet AS-level graphs of
South Korea and Japan and obtain similar results. Some practical suggestions
are presented to optimize such real-world interconnected networks accordingly.Comment: 8 page
Powder alignment system for anisotropic bonded NdFeB Halbach cylinders
A Halbach cylinder, fabricated from pre-magnetized sintered NdFeB magnet segments, is proposed for the powder aligning system during the compression or injection moulding of anisotropic bonded Halbach oriented NdFeB ring magnets. The influence of leading design parameters of the powder aligning system, viz. the number of magnet segments per pole, their axial length and radial thickness, and their clearance from the mould, is investigated by finite element analysis, and validated experimentall
Analysis of anisotropic bonded NdFeB Halbach cylinders accounting for partial powder alignment
An analytical technique is developed for predicting the performance of a bonded Halbach oriented anisotropic magnet, with due account of partial alignment of the NdFeB powder during injection molding. The predicted performance of a 12-pole injection molded, Halbach oriented magnet is compared with measuremen
Rotor eddy-current loss in permanent magnet brushless machines
This paper presents an analysis of the rotor eddy-current loss in modular and conventional topologies of permanent magnet brushless machine. The loss is evaluated both analytically and by time-stepped finite-element analysis, and it is shown that it can be significant in both machine topologies. It is also shown that the loss can be reduced significantly by segmenting the magnets
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