6,250 research outputs found

    Analyticity of a class of degenerate evolution equations on the canonical simplex of Rd\R^d arising from Fleming--Viot processes

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    We study the analyticity of the semigroups generated by a class of degenerate second order differential operators in the space C(Sd)C(S_d), where SdS_d is the canonical simplex of Rd\R^d. The semigroups arise from the theory of Fleming--Viot processes in population genetics.Comment: 32 page

    Dependency-aware unequal erasure protection codes

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    Classical unequal erasure protection schemes split data to be protected into classes which are encoded independently. The unequal protection scheme presented in this paper is based on an erasure code which encodes all the data together according to the existing dependencies. A simple algorithm generates dynamically the generator matrix of the erasure code according to the packets streams structure, i.e., the dependencies between the packets, and the rate of the code. This proposed erasure code was applied to a packetized MPEG4 stream transmitted over a packet erasure channel and compared with other classical protection schemes in terms of PSNR and MOS. It is shown that the proposed code allows keeping a high video quality-level in a larger packet loss rate range than the other protection schemes

    Adjoint bi-continuous semigroups and semigroups on the space of measures

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    For a given bi-continuous semigroup T on a Banach space X we define its adjoint on an appropriate closed subspace X^o of the norm dual X'. Under some abstract conditions this adjoint semigroup is again bi-continuous with respect to the weak topology (X^o,X). An application is the following: For K a Polish space we consider operator semigroups on the space C(K) of bounded, continuous functions (endowed with the compact-open topology) and on the space M(K) of bounded Baire measures (endowed with the weak*-topology). We show that bi-continuous semigroups on M(K) are precisely those that are adjoints of a bi-continuous semigroups on C(K). We also prove that the class of bi-continuous semigroups on C(K) with respect to the compact-open topology coincides with the class of equicontinuous semigroups with respect to the strict topology. In general, if K is not Polish space this is not the case

    Clean Zones: The Dirty Side of Super Bowl XLVI

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    Are Happy Individuals Less Xenophobic Than Unhappy Individuals? Happiness & Income Versus Xenophobia

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    The social science literature on xenophobia is immense. Researchers have found that individual levels of xenophobia have a strong correlation with economic indicators, education, and political affiliation. However, do they have any correlation with unconventional indicators like happiness? This paper uses data from the World Value Survey to study the correlation between individual happiness and xenophobia. I find that there is a significant correlation between individual levels of happiness and xenophobia, even when controlling for income around the world
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