6,188 research outputs found
Evolution of the Dependence of Residual Lifetimes
We investigate the dependence properties of a vector of residual lifetimes by means of the copula associated with the conditional distribution function. In particular, the evolution of positive dependence properties (like quadrant dependence and total positivity) are analyzed and expressions for the evolution of measures of association are given
Water-waves modes trapped in a canal by a body with the rough surface
The problem about a body in a three dimensional infinite channel is
considered in the framework of the theory of linear water-waves. The body has a
rough surface characterized by a small parameter while the
distance of the body to the water surface is also of order . Under a
certain symmetry assumption, the accumulation effect for trapped mode
frequencies is established, namely, it is proved that, for any given and
integer , there exists such that the problem has at
least eigenvalues in the interval of the continuous spectrum in the
case . The corresponding eigenfunctions decay
exponentially at infinity, have finite energy, and imply trapped modes.Comment: 25 pages, 8 figure
The localization effect for eigenfunctions of the mixed boundary value problem in a thin cylinder with distorted ends
A simple sufficient condition on curved end of a straight cylinder is found
that provides a localization of the principal eigenfunction of the mixed
boundary value for the Laplace operator with the Dirichlet conditions on the
lateral side. Namely, the eigenfunction concentrates in the vicinity of the
ends and decays exponentially in the interior. Similar effects are observed in
the Dirichlet and Neumann problems, too.Comment: 25 pages, 10 figure
A model for the analysis of security policies in service function chains
Two emerging architectural paradigms, i.e., Software Defined Networking (SDN)
and Network Function Virtualization (NFV), enable the deployment and management
of Service Function Chains (SFCs). A SFC is an ordered sequence of abstract
Service Functions (SFs), e.g., firewalls, VPN-gateways,traffic monitors, that
packets have to traverse in the route from source to destination. While this
appealing solution offers significant advantages in terms of flexibility, it
also introduces new challenges such as the correct configuration and ordering
of SFs in the chain to satisfy overall security requirements. This paper
presents a formal model conceived to enable the verification of correct policy
enforcements in SFCs. Software tools based on the model can then be designed to
cope with unwanted network behaviors (e.g., security flaws) deriving from
incorrect interactions of SFs in the same SFC
Courts in more republican-leaning counties sentence black individuals to longer prison terms than white individuals
The United States puts more people in prison than any other country in the world, and Black and Latinx individuals are disproportionately incarcerated and for longer. In new research which examines over 500,000 people admitted to state prisons through county courts, Katherine A. Durante finds that Black and Latinx individuals are sentenced, on average, for longer than White individuals, and that Black individuals are sentenced more harshly as the percentage of voters for Donald Trump in a county increases. These findings, she writes, raise questions of bias and unequal justice in the US justice system
Chromosome Aberrations in Astronauts
A review of currently available data on in vivo induced chromosome damage in the blood lymphocytes of astronauts proves that, after protracted exposure of a few months or more to space radiation, cytogenetic biodosimetry analyses of blood collected within a week or two of return from space provides a reliable estimate of equivalent radiation dose and risk. Recent studies indicate that biodosimetry estimates from single spaceflights lie within the range expected from physical dosimetry and biophysical models, but very large uncertainties are associated with single individual measurements and the total sample population remains low. Retrospective doses may be more difficult to estimate because of the fairly rapid time-dependent loss of "stable" aberrations in blood lymphocytes. Also, biodosimetry estimates from individuals who participate in multiple missions, or very long (interplanetary) missions, may be complicated by an adaptive response to space radiation and/or changes in lymphocyte survival and repopulation. A discussion of published data is presented and specific issues related to space radiation biodosimetry protocols are discussed
How does monetary policy affect investment in the euro area?
We set out to analyze the monetary policy transmission mechanism by documenting how the annual investment of more than one million firms in Germany, Spain, France and Italy responded to monetary policy shocks between 2000 and 2016. We show that euro area firms react differently depending on their age and the industry they operate in: young firms and those producing durable goods react more strongly than the average firm. This confirms that monetary policy is affecting firms’ investment through two different channels. On the one hand, the interest rate channel affects demand for durable goods more than demand for services, which in turn affects investment demand from the producers of those goods. On the other hand, as young firms are more likely to face financing constraints, their stronger than average reaction can be explained by the balance sheet channel of monetary policy transmission
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