7,866 research outputs found
Promarc: An Online Skills and Projects Marketplace
Technical projects can vary greatly in terms of cost, complexity, and time. Project leads spend a lot of valuable time and energy making sure that their teams are organized and on-task. A major part of their responsibilities includes putting together a team with the right skills in order to maximize efficiency. Having a platform where project leads can quickly find team members with the right skills would save them a lot of stress and trouble. The goal of this project is to deliver such a platform, where users can make posts about their projects and the technical skills that they require, and be connected to an entire network of potential viable team members. Our system consists of a web application connected to a database backend, accessible through different interfaces depending on the credentials of the user. This report will also provide an in-depth analysis on the systems requirements specifications, use cases, data flow, involved actors, architecture, testing procedures, risk analysis, development timeline, final results, and societal impact
Tamagawa numbers of polarized algebraic varieties
Let be an ample metrized invertible sheaf on
a smooth quasi-projective algebraic variety defined over a number field.
Denote by the number of rational points in having -height . We consider the problem of a geometric and arithmetic
interpretation of the asymptotic for as in
connection with recent conjectures of Fujita concerning the Minimal Model
Program for polarized algebraic varieties.
We introduce the notions of -primitive varieties and -primitive fibrations. For -primitive varieties over we
propose a method to define an adelic Tamagawa number which
is a generalization of the Tamagawa number introduced by Peyre for
smooth Fano varieties. Our method allows us to construct Tamagawa numbers for
-Fano varieties with at worst canonical singularities. In a series of
examples of smooth polarized varieties and singular Fano varieties we show that
our Tamagawa numbers express the dependence of the asymptotic of on the choice of -adic metrics on .Comment: 54 pages, minor correction
Spare capacity allocation using shared backup path protection for dual link failures
This paper extends the spare capacity allocation (SCA) problem from single link failure [1] to dual link failures on mesh-like IP or WDM networks. The SCA problem pre-plans traffic flows with mutually disjoint one working and two backup paths using the shared backup path protection (SBPP) scheme. The aggregated spare provision matrix (SPM) is used to capture the spare capacity sharing for dual link failures. Comparing to a previous work by He and Somani [2], this method has better scalability and flexibility. The SCA problem is formulated in a non-linear integer programming model and partitioned into two sequential linear sub-models: one finds all primary backup paths first, and the other finds all secondary backup paths next. The results on five networks show that the network redundancy using dedicated 1+1+1 is in the range of 313-400%. It drops to 96-181% in 1:1:1 without loss of dual-link resiliency, but with the trade-off of using the complicated share capacity sharing among backup paths. The hybrid 1+1:1 provides intermediate redundancy ratio at 187-310% with a moderate complexity. We also compare the passive/active approaches which consider spare capacity sharing after/during the backup path routing process. The active sharing approaches always achieve lower redundancy values than the passive ones. These reduction percentages are about 12% for 1+1:1 and 25% for 1:1:1 respectively
Fredholm conditions on non-compact manifolds: theory and examples
We give explicit Fredholm conditions for classes of pseudodifferential
operators on suitable singular and non-compact spaces. In particular, we
include a "user's guide" to Fredholm conditions on particular classes of
manifolds including asymptotically hyperbolic manifolds, asymptotically
Euclidean (or conic) manifolds, and manifolds with poly-cylindrical ends. The
reader interested in applications should be able read right away the results
related to those examples, beginning with Section 5. Our general, theoretical
results are that an operator adapted to the geometry is Fredholm if, and only
if, it is elliptic and all its limit operators, in a sense to be made precise,
are invertible. Central to our theoretical results is the concept of a Fredholm
groupoid, which is the class of groupoids for which this characterization of
the Fredholm condition is valid. We use the notions of exhaustive and strictly
spectral families of representations to obtain a general characterization of
Fredholm groupoids. In particular, we introduce the class of the so-called
groupoids with Exel's property as the groupoids for which the regular
representations are exhaustive. We show that the class of "stratified
submersion groupoids" has Exel's property, where stratified submersion
groupoids are defined by glueing fibered pull-backs of bundles of Lie groups.
We prove that a stratified submersion groupoid is Fredholm whenever its
isotropy groups are amenable. Many groupoids, and hence many pseudodifferential
operators appearing in practice, fit into this framework. This fact is explored
to yield Fredholm conditions not only in the above mentioned classes, but also
on manifolds that are obtained by desingularization or by blow-up of singular
sets
Uniform shift estimates for transmission problems and optimal rates of convergence for the parametric Finite Element Method
Let \Omega \subset \RR^d, , be a bounded domain with
piecewise smooth boundary and let be an open subset of a
Banach space . Motivated by questions in "Uncertainty Quantification," we
consider a parametric family of uniformly strongly
elliptic, second order partial differential operators on . We
allow jump discontinuities in the coefficients. We establish a regularity
result for the solution u: \Omega \times U \to \RR of the parametric,
elliptic boundary value/transmission problem , , with
mixed Dirichlet-Neumann boundary conditions in the case when the boundary and
the interface are smooth and in the general case for . Our regularity and
well-posedness results are formulated in a scale of broken weighted Sobolev
spaces \hat\maK^{m+1}_{a+1}(\Omega) of Babu\v{s}ka-Kondrat'ev type in
, possibly augmented by some locally constant functions. This implies
that the parametric, elliptic PDEs admit a shift theorem that
is uniform in the parameter . In turn, this then leads to
-quasi-optimal rates of convergence (i.e. algebraic orders of convergence)
for the Galerkin approximations of the solution , where the approximation
spaces are defined using the "polynomial chaos expansion" of with respect
to a suitable family of tensorized Lagrange polynomials, following the method
developed by Cohen, Devore, and Schwab (2010)
Decays of Pentaquarks in Hadrocharmonium and Molecular Pictures
We consider decays of the hidden charm LHCb pentaquarks in the
hadrocharmonium and molecular scenarios. In both pictures the LHCb pentaquarks
are essentially nonrelativistic bound states. We develop a semirelativistic
framework for calculation of the partial decay widths that allows the final
particles to be relativistic. Using this approach we calculate the decay widths
in the hadrocharmonium and molecular pictures. Molecular hidden charm
pentaquarks are constructed as loosely bound states of charmed and anticharmed
hadrons. Calculations show that molecular pentaquarks decay predominantly into
states with open charm. Strong suppression of the molecular pentaquark decays
into states with hidden charm is qualitatively explained by a relatively large
size of the molecular pentaquark. The decay pattern of hadrocharmonium
pentaquarks that are interpreted as loosely bound states of excited charmonium
and nucleons is quite different. This time dominate decays into states
with hidden charm, but suppression of the decays with charm exchange is weaker
than in the respective molecular case. The weaker suppression is explained by a
larger binding energy and respectively smaller size of the hadrocharmonium
pentaquarks. These results combined with the experimental data on partial decay
widths could allow to figure out which of the two theoretical scenarios for
pentaquarks (if either) is chosen by nature.Comment: 33 pages, 14 figures; v2: minor editorial changes, version published
in Phys. Rev.
- …