15,808 research outputs found
New Measurements of Upsilon Spin Alignment at the Tevatron
We describe a new analysis of Upsilon(nS) to mu+mu- decays collected in
proton anti-proton collisions with the CDF II detector at the Fermilab
Tevatron. This analysis measures the angular distributions of the final state
muons in the Upsilon rest frame, providing new information about Upsilon
production polarization. We find the angular distributions to be nearly
isotropic up to Upsilon transverse momentum of 40 GeV/c, consistent with
previous measurements by CDF, but inconsistent with results obtained by the D0
experiment. The results are compared with recent NLO calculations based on
color-singlet matrix elements and non-relativistic QCD with color-octet matrix
elements.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 4 pages, 5 figure
'5 Minutes With Matt': the Innovative use of Micro Video Blogging in Higher Education
Recent developments in online learning platforms and associated technologies have changed the dynamics of higher education by forcing practitioners to reconsider traditional assumptions of teaching and learning (Garrison & Kanuka, 2004). This has fundamentally changed the nature and parameters of pedagogy within higher education whilst also shifting the associated expectations of students (HEA, 2000). Today, face-to-face teaching alone is considered somewhat antiquated; instead an effective higher education practitioner is now someone who can draw upon a myriad of blended learning strategies (see HEFCE, 2009). Because of this, the author of this paper contends that it is a fundamental responsibility of higher education practitioners today to be responsive to such changes and to continually seek ways of innovatively ‘blending’ traditional face-to-face methods of teaching and learning with new technologies and online platforms. In this vein, this short paper provides an example of how micro-video-blogging has been used as a blended learning tool within a social science programme
Content-based ontology ranking
Techniques to rank ontologies are crucial to aid and encourage the re-use of publicly available ontologies. This paper presents a system that obtains a list of ontologies from a search engine that contain the terms provided by a knowledge engineer and ranks them. The ranking of these ontologies will be done according to how many of the concept labels in those ontologies match a set of terms extracted from a corpus of documents related to the domain of knowledge identified by the knowledge engineer's original search terms
Relaxing The Hamilton Jacobi Bellman Equation To Construct Inner And Outer Bounds On Reachable Sets
We consider the problem of overbounding and underbounding both the backward
and forward reachable set for a given polynomial vector field, nonlinear in
both state and input, with a given semialgebriac set of initial conditions and
with inputs constrained pointwise to lie in a semialgebraic set. Specifically,
we represent the forward reachable set using the value function which gives the
optimal cost to go of an optimal control problems and if smooth satisfies the
Hamilton-Jacobi- Bellman PDE. We then show that there exist polynomial upper
and lower bounds to this value function and furthermore, these polynomial
sub-value and super-value functions provide provable upper and lower bounds to
the forward reachable set. Finally, by minimizing the distance between these
sub-value and super-value functions in the L1-norm, we are able to construct
inner and outer bounds for the reachable set and show numerically on several
examples that for relatively small degree, the Hausdorff distance between these
bounds is negligible
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