4,691 research outputs found
Entropic Ricci curvature bounds for discrete interacting systems
We develop a new and systematic method for proving entropic Ricci curvature
lower bounds for Markov chains on discrete sets. Using different methods, such
bounds have recently been obtained in several examples (e.g., 1-dimensional
birth and death chains, product chains, Bernoulli-Laplace models, and random
transposition models). However, a general method to obtain discrete Ricci
bounds had been lacking. Our method covers all of the examples above. In
addition, we obtain new Ricci curvature bounds for zero-range processes on the
complete graph. The method is inspired by recent work of Caputo, Dai Pra and
Posta on discrete functional inequalities.Comment: Published at http://dx.doi.org/10.1214/15-AAP1133 in the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Sea surface temperature, marine productivity and terrigenous fluxes in the western Bering Sea during the last 150 ka
Late Pleistocene to Holocene paleoceanographic reconstructions at Shirshov Ridge, western Bering Sea
Late Pleistocene to Holocene variations of sea surface conditions and intermediate water ventilation in the western Bering Sea
Deglacial variability of sea surface temperature and salinity in the subarctic North Pacific and its marginal seas
Designing wheelchair-based movement games
People using wheelchairs have access to fewer sports and other physically stimulating leisure activities than nondisabled persons, and often lead sedentary lifestyles that negatively influence their health. While motion- based video games have demonstrated great potential of encouraging physical activity among nondisabled players, the accessibility of motion-based games is limited for persons with mobility disabilities, thus also limiting access to the potential health benefits of playing these games. In our work, we address this issue through the design of wheelchair-accessible motion-based game controls. We present KINECTWheels, a toolkit designed to integrate wheelchair movements into motion-based games. Building on the toolkit, we developed Cupcake Heaven, a wheelchair-based video game designed for older adults using wheelchairs, and we created Wheelchair Revolution, a motion-based dance game that is accessible to both persons using wheelchairs and nondisabled players. Evaluation results show that KINECTWheels can be applied to make motion-based games wheelchair-accessible, and that wheelchair-based games engage broad audiences in physically stimulating play. Through the application of the wheelchair as an enabling technology in games, our work has the potential of encouraging players of all ages to develop a positive relationship with their wheelchair
An axiomatic approach to default risk and model uncertainty in rating systems
In this paper, we deal with an axiomatic approach to default risk. We
introduce the notion of a default risk measure, which generalizes the classical
probability of default (PD), and allows to incorporate model risk in various
forms. We discuss different properties and representations of default risk
measures via monetary risk measures, families of related tail risk measures,
and Choquet capacities. In a second step, we turn our focus on default risk
measures, which are given as worst-case PDs and distorted PDs. The latter are
frequently used in order to take into account model risk for the computation of
capital requirements through risk-weighted assets (RWAs), as demanded by the
Capital Requirement Regulation (CRR). In this context, we discuss the impact of
different default risk measures and margins of conservatism on the amount of
risk-weighted assets.Comment: References have been updated, typos have been corrected, final
version to appear in Journal of Mathematical Economic
A representation theorem for end spaces of infinite graphs
End spaces of infinite graphs sit at the interface between graph theory,
group theory and topology. They arise as the boundary of an infinite graph in a
standard sense generalising the theory of the Freudenthal boundary developed by
Freudenthal and Hopf in the 1940's for infinite groups.
A long-standing quest in infinite graph theory with a rich body of literature
seeks to describe the possible end structures of graphs by a set of
low-complexity representatives. In this paper we present a solution to this
fifty-year-old problem by showing that every end space is homeomorphic to the
end space of some (uniform graph on a) special order tree.Comment: 23 pages. V2 adds a moreover-part to Theorem 3.
Bilingualism, Multilingualism, Globalization and Superdiversity:Toward Sociolinguistic Repertoires
A survey of developments in research on sociolinguistic superdiversity, emphasizing the increased relevance of repertoires as focus of research
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