4,876 research outputs found
Polarised and Unpolarised Charmonium Production at Higher Orders in v
We study the unpolarised and polarised hadro-production of charmonium in
non-relativistic QCD (NRQCD) at low transverse momentum, including sufficiently
higher orders in the relative velocity, , so as to study the ratio of
and production rates.Comment: 4 pages, 1 Postscript figure, LaTeX, Presented at the QCD97
Euroconference, Montpellier, July 3-9, 1997, to appear in Nuclear Physics B
Proceedings Supplemen
When is a Function Securely Computable?
A subset of a set of terminals that observe correlated signals seek to
compute a given function of the signals using public communication. It is
required that the value of the function be kept secret from an eavesdropper
with access to the communication. We show that the function is securely
computable if and only if its entropy is less than the "aided secret key"
capacity of an associated secrecy generation model, for which a single-letter
characterization is provided
Dynamic Motion Planning for Aerial Surveillance on a Fixed-Wing UAV
We present an efficient path planning algorithm for an Unmanned Aerial
Vehicle surveying a cluttered urban landscape. A special emphasis is on
maximizing area surveyed while adhering to constraints of the UAV and partially
known and updating environment. A Voronoi bias is introduced in the
probabilistic roadmap building phase to identify certain critical milestones
for maximal surveillance of the search space. A kinematically feasible but
coarse tour connecting these milestones is generated by the global path
planner. A local path planner then generates smooth motion primitives between
consecutive nodes of the global path based on UAV as a Dubins vehicle and
taking into account any impending obstacles. A Markov Decision Process (MDP)
models the control policy for the UAV and determines the optimal action to be
undertaken for evading the obstacles in the vicinity with minimal deviation
from current path. The efficacy of the proposed algorithm is evaluated in an
updating simulation environment with dynamic and static obstacles.Comment: Accepted at International Conference on Unmanned Aircraft Systems
201
Perturbations of planar algebras
We analyze the effect of pivotal structures (on a 2-category) on the planar
algebra associated to a 1-cell as in \cite{Gho08} and come up with the notion
of {\em perturbations of planar algebras by weights} (a concept that appeared
earlier in Michael Burns' thesis \cite{Bur03}); we establish a one-to-one
correspondence between weights and pivotal structures. Using the construction
of \cite{Gho08}, to each bifinite bimodule over -factors, we associate a
{\em bimodule planar algebra} in such a way that extremality of the bimodule
corresponds to sphericality of the planar algebra. As a consequence of this, we
reproduce an extension of Jones' theorem (\cite{Jon}) (of associating
`subfactor planar algebras' to extremal subfactors). Conversely, given a
bimodule planar algebra, we construct a bifinite bimodule whose associated
bimodule planar algebra is the one which we start with, using perturbations and
Jones-Walker-Shlyakhtenko-Kodiyalam-Sunder method of reconstructing an extremal
subfactor from a subfactor planar algebra. The perturbation technique helps us
to construct an example of a family of non-spherical planar algebras starting
from a particular spherical one; we also show that this family is associated to
a known family of subfactors constructed by Jones.Comment: 28 page
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