124,598 research outputs found
Cluster mean-field approximations with the coherent-anomaly-method analysis for the driven pair contact process with diffusion
The cluster mean-field approximations are performed, up to 13 cluster sizes,
to study the critical behavior of the driven pair contact process with
diffusion (DPCPD) and its precedent, the PCPD in one dimension. Critical points
are estimated by extrapolating our data to the infinite cluster size limit,
which are in good accordance with recent simulation results. Within the cluster
mean-field approximation scheme, the PCPD and the DPCPD share the same
mean-field critical behavior. The application of the coherent anomaly method,
however, shows that the two models develop different coherent anomalies, which
lead to different true critical scaling. The values of the critical exponents
for the particle density, the pair density, the correlation length, and the
relaxation time are fairly well estimated for the DPCPD. These results support
and complement our recent simulation results for the DPCPD
Human Capital Spending, Inequality, and Growth in Middle-Income Asia
Asia’s rapid population aging fortifies the case for strengthening human capital investments. Further, the experience of the newly industrialized economies suggests that human capital investments will be a vital ingredient of the transition from middle income to high income. Those investments can also affect equity and public finances. In this paper, we use data from the National Transfer Accounts to empirically analyze the effect of human capital investment in Asian countries on economic growth, inequality, and fiscal balance. Our empirical evidence suggests that human capital investments have a positive effect on labor productivity and, hence, output. The positive effect is stronger for poorer households and, hence, beneficial for equity. We also find that such investments can generate sufficient tax revenues to improve the fiscal balance. Overall, our evidence points to a positive effect of human capital on growth, equity, and fiscal balance in Asia
Towards Efficient Full Pose Omnidirectionality with Overactuated MAVs
Omnidirectional MAVs are a growing field, with demonstrated advantages for
aerial interaction and uninhibited observation. While systems with complete
pose omnidirectionality and high hover efficiency have been developed
independently, a robust system that combines the two has not been demonstrated
to date. This paper presents VoliroX: a novel omnidirectional vehicle that can
exert a wrench in any orientation while maintaining efficient flight
configurations. The system design is presented, and a 6 DOF geometric control
that is robust to singularities. Flight experiments further demonstrate and
verify its capabilities.Comment: 10 pages, 6 figures, ISER 2018 conference submissio
A note on Hawking radiation via complex path analysis
As long as we neglect backreaction, the Hawking temperature of a given black
hole would not depend upon the parameters of the particle species we are
considering. In the semiclassical complex path analysis approach of Hawking
radiation, this has been verified by taking scalar and Dirac spinors separately
for different stationary spacetime metrics. Here we show, in a coordinate
independent way that, for an arbitrary spacetime with any number of dimensions,
the equations of motion for a Dirac spinor, a vector, spin- and
spin- fields reduce to Klein-Gordon equations in the WKB
semiclassical limit. We then obtain, under some suitable assumptions, the
complex solutions of those resulting scalar equations across the Killing
horizon of a stationary spacetime to get a coordinate independent expression
for the emission probability identical for all particle species. Finally we
consider some explicit examples to demonstrate the validity of that expression.Comment: 12 pages, v2; manuscript divided into sections, many discussions and
references adde
Core-periphery organization of complex networks
Networks may, or may not, be wired to have a core that is both itself densely
connected and central in terms of graph distance. In this study we propose a
coefficient to measure if the network has such a clear-cut core-periphery
dichotomy. We measure this coefficient for a number of real-world and model
networks and find that different classes of networks have their characteristic
values. For example do geographical networks have a strong core-periphery
structure, while the core-periphery structure of social networks (despite their
positive degree-degree correlations) is rather weak. We proceed to study radial
statistics of the core, i.e. properties of the n-neighborhoods of the core
vertices for increasing n. We find that almost all networks have unexpectedly
many edges within n-neighborhoods at a certain distance from the core
suggesting an effective radius for non-trivial network processes
Remarks on the Scalar Graviton Decoupling and Consistency of Horava Gravity
Recently Horava proposed a renormalizable gravity theory with higher
derivatives by abandoning the Lorenz invariance in UV. But there have been
confusions regarding the extra scalar graviton mode and the consistency of the
Horava model. I reconsider these problems and show that, in the Minkowski
vacuum background, the scalar graviton mode can be consistency decoupled from
the usual tensor graviton modes by imposing the (local) Hamiltonian as well as
the momentum constraints.Comment: Some clarifications regarding the projectable case added, Typos
corrected, Comments (Footnote No.9, Note Added) added, References updated,
Accepted in CQ
Comments on "Entropy of 2D Black Holes from Counting Microstates"
In a recent letter, Cadoni and Mignemi proposed a formulation for the
statistical computation of the 2D black holes entropy. We present a criticism
about their formulation.Comment: 5 pages, Latex, no figure
Finite element solution of low bond number sloshing
The dynamics of liquid propellant in a low Bond number environment which are critical to the design of spacecraft systems with respect to orbital propellant transfer and attitude control system were investigated. Digital computer programs were developed for the determination of liquid free surface equilibrium shape, lateral slosh natural vibration mode shapes, and frequencies for a liquid in a container of arbitrary axisymmetric shape with surface tension forces the same order of magnitude as acceleration forces. A finite volume element representation of the liquid was used for the vibration analysis. The liquid free surface equilibrium shapes were computed for several tanks at various contact angles and ullage volumes. A configuration was selected for vibration analysis and lateral slosh mode shapes and natural frequencies were obtained. Results are documented
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