2,505 research outputs found
Lunar mission performance evaluation procedure for orbit-launched nuclear vehicles
Lunar mission performance evaluation procedure for orbit-launched vehicles with nuclear propulsion syste
A supply chain approach to meat goat industry development
The Victorian goat meat industry is a significant contributor to export earnings, which is derived largely from the harvest of feral goats. The potential for exports of farmed goat meat into Asian product markets is being developed in a supply chain approach with producers, processors, exporters and Asian importers. Producers have been networked in four locations to improve supply capability and participate in production and economic benchmarking. In the absence of an existing market for premium farmed goat meat, a larger group of producers are cooperating with a marketer to develop a niche market in the Asian food service sector. This presents a challenge to the group in developing commercial relationships and playing a role in the marketing of their goat meat
Private Aggregation from Fewer Anonymous Messages
Consider the setup where parties are each given a number and the goal is to compute the sum in a secure
fashion and with as little communication as possible. We study this problem in
the anonymized model of Ishai et al. (FOCS 2006) where each party may broadcast
anonymous messages on an insecure channel.
We present a new analysis of the one-round "split and mix" protocol of Ishai
et al. In order to achieve the same security parameter, our analysis reduces
the required number of messages by a multiplicative factor. We
complement our positive result with lower bounds showing that the dependence of
the number of messages on the domain size, the number of parties, and the
security parameter is essentially tight.
Using a reduction of Balle et al. (2019), our improved analysis of the
protocol of Ishai et al. yields, in the same model, an -differentially private protocol for aggregation that, for any
constant and any ,
incurs only a constant error and requires only a constant number of messages
per party. Previously, such a protocol was known only for
messages per party.Comment: 31 pages; 1 tabl
Measuring the Small-Scale Power Spectrum of Cosmic Density Fluctuations Through 21 cm Tomography Prior to the Epoch of Structure Formation
The thermal evolution of the cosmic gas decoupled from that of the cosmic
microwave background (CMB) at a redshift z~200. Afterwards and before the first
stars had formed, the cosmic neutral hydrogen absorbed the CMB flux at its
resonant 21cm spin-flip transition. We calculate the evolution of the spin
temperature for this transition and the resulting anisotropies that are
imprinted on the CMB sky due to linear density fluctuations during this epoch.
These anisotropies at an observed wavelength of 10.56[(1+z)/50] meters, contain
an amount of information that is orders of magnitude larger than any other
cosmological probe. Their detection, although challenging, could tightly
constrain any possible running of the spectral index from inflation (as
suggested by WMAP), small deviations from Gaussianity, or any significant
contribution from neutrinos or warm dark matter to the cosmic mass budget.Comment: 4 pages, 3 figures, accepted for publication in Physical Review
Letter
Risk-Averse Matchings over Uncertain Graph Databases
A large number of applications such as querying sensor networks, and
analyzing protein-protein interaction (PPI) networks, rely on mining uncertain
graph and hypergraph databases. In this work we study the following problem:
given an uncertain, weighted (hyper)graph, how can we efficiently find a
(hyper)matching with high expected reward, and low risk?
This problem naturally arises in the context of several important
applications, such as online dating, kidney exchanges, and team formation. We
introduce a novel formulation for finding matchings with maximum expected
reward and bounded risk under a general model of uncertain weighted
(hyper)graphs that we introduce in this work. Our model generalizes
probabilistic models used in prior work, and captures both continuous and
discrete probability distributions, thus allowing to handle privacy related
applications that inject appropriately distributed noise to (hyper)edge
weights. Given that our optimization problem is NP-hard, we turn our attention
to designing efficient approximation algorithms. For the case of uncertain
weighted graphs, we provide a -approximation algorithm, and a
-approximation algorithm with near optimal run time. For the case
of uncertain weighted hypergraphs, we provide a
-approximation algorithm, where is the rank of the
hypergraph (i.e., any hyperedge includes at most nodes), that runs in
almost (modulo log factors) linear time.
We complement our theoretical results by testing our approximation algorithms
on a wide variety of synthetic experiments, where we observe in a controlled
setting interesting findings on the trade-off between reward, and risk. We also
provide an application of our formulation for providing recommendations of
teams that are likely to collaborate, and have high impact.Comment: 25 page
Age-specific vaccine effectiveness of seasonal 2010/2011 and pandemic influenza A(H1N1) 2009 vaccines in preventing influenza in the United Kingdom
An analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI x6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group
Neutrino oscillation physics at an upgraded CNGS with large next generation liquid Argon TPC detectors
The determination of the missing element (magnitude and phase) of
the PMNS neutrino mixing matrix is possible via the detection of \numu\to\nue
oscillations at a baseline and energy given by the atmospheric
observations, corresponding to a mass squared difference . While the current optimization of the CNGS
beam provides limited sensitivity to this reaction, we discuss in this document
the physics potential of an intensity upgraded and energy re-optimized CNGS
neutrino beam coupled to an off-axis detector. We show that improvements in
sensitivity to compared to that of T2K and NoVA are possible with
a next generation large liquid Argon TPC detector located at an off-axis
position (position rather distant from LNGS, possibly at shallow depth). We
also address the possibility to discover CP-violation and disentangle the mass
hierarchy via matter effects. The considered intensity enhancement of the CERN
SPS has strong synergies with the upgrade/replacement of the elements of its
injector chain (Linac, PSB, PS) and the refurbishing of its own elements,
envisioned for an optimal and/or upgraded LHC luminosity programme.Comment: 37 pages, 20 figure
Mind the gap? The persistence of pathological discourses in urban regeneration policy
Urban regeneration policy has historically framed policy problems using a discourse that pathologises areas and spatial communities. Since 2001 in England, and 2002 in Scotland a structural change in policy has occurred where citywide partnerships are now meant overcome structural spatial inequalities, countering pathological explanations. This paper uses historical and discourse analysis to evaluate one of the major community regeneration strategies developed by the Scottish Executive in 2002: Better Communities in Scotland: Closing the Gap. It seeks to ask whether structural change in policy was paralleled by discursive change; what discursive path dependence is evidenced? The text is placed in the historic context of UK urban renewal policies dating back to the launch of the Urban Programme in 1968 and particularly the policy discourse created by the influential Conservative government policy of 1988 New Life for Urban Scotland and the wider discourses of poverty and neighbourhood renewal policy created by Labour governments since 1997. The close textual analysis of the text shows that Better Communities in Scotland continues to pathologise spatial communities. Although this suggests a degree of historical path dependency, the historic breadth of the analysis also problematises simple historical determinism
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