6,174 research outputs found
Security in Wireless Sensor Networks: Issues and Challenges
Wireless Sensor Network (WSN) is an emerging technology that shows great
promise for various futuristic applications both for mass public and military.
The sensing technology combined with processing power and wireless
communication makes it lucrative for being exploited in abundance in future.
The inclusion of wireless communication technology also incurs various types of
security threats. The intent of this paper is to investigate the security
related issues and challenges in wireless sensor networks. We identify the
security threats, review proposed security mechanisms for wireless sensor
networks. We also discuss the holistic view of security for ensuring layered
and robust security in wireless sensor networks.Comment: 6 page
Copula-Based Nonlinear Models of Spatial Market Linkages
Replaced with revised version of paper 06/28/11.Spatial Market Linkages, Copula Models, State-dependence, Forest Products, Research Methods/ Statistical Methods,
Nonlinear Models of Exchange Rate Pass-Through in International Forest Product Markets
Forest Products, International Price Linkages, Exchange Rate Pass-Through, Vector Error Correction Models (VECM), Thresholds, International Relations/Trade, Research Methods/ Statistical Methods,
An instrument to measure fast gas phase radical kinetics at hight temperatures and pressures
Fast radical reactions are central to the chemistry of planetary atmospheres and combustion systems. Laser-induced fluorescence is a highly sensitive and selective technique that can be used to monitor a number of radical species in kinetics experiments, but is typically limited to low pressure systems owing to quenching of fluorescent states at higher pressures. The design and characterisation of an instrument is reported using laser-induced fluorescence detection to monitor fast radical kinetics (up to 25,000 s-1) at high temperatures and pressures by sampling from a high pressure reaction region to a low pressure detection region. Kinetics have been characterised at temperatures reaching 740 K and pressures up to 2 atm, with expected maximum operational conditions of up to ~ 900 K and ~ 5 atm. The distance between the point of sampling from the high pressure region and the point of probing within the low pressure region is critical to the measurement of fast kinetics. The instrumentation described in this work can be applied to the measurement of kinetics relevant to atmospheric and combustion chemistry
Commissioning of the CMS zero degree calorimeter using LHC beam
This paper reports on the commissioning and first running experience of the
CMS Zero Degree Calorimeters during December 2009. All channels worked
correctly. The ZDCs were timed into the data acquisition system using beam
splash events. These data also allowed us to make a first estimate of
channel-by-channel variations in gain.Comment: 6 pages, 8 figures, Presented at CALOR2010: 14th International
Conference for Calorimetry in High Energy Physic
Spin-Splitter Studies: Polarization Stability Measurements at IUCF
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Forward Neutron Production at the Fermilab Main Injector
We have measured cross sections for forward neutron production from a variety
of targets using proton beams from the Fermilab Main Injector. Measurements
were performed for proton beam momenta of 58 GeV/c, 84 GeV/c, and 120 GeV/c.
The cross section dependence on the atomic weight (A) of the targets was found
to vary as where is for a beam momentum of
58 GeV/c and 0.540.05 for 120 GeV/c. The cross sections show reasonable
agreement with FLUKA and DPMJET Monte Carlos. Comparisons have also been made
with the LAQGSM Monte Carlo.Comment: Accepted for publication in Physical Review D. This version
incorporates small changes suggested by referee and small corrections in the
neutron production cross sections predicted by FLUK
Measurement of Charged Pion Production Yields off the NuMI Target
The fixed-target MIPP experiment, Fermilab E907, was designed to measure the
production of hadrons from the collisions of hadrons of momenta ranging from 5
to 120 GeV/c on a variety of nuclei. These data will generally improve the
simulation of particle detectors and predictions of particle beam fluxes at
accelerators. The spectrometer momentum resolution is between 3 and 4%, and
particle identification is performed for particles ranging between 0.3 and 80
GeV/c using , time-of-flight and Cherenkov radiation measurements. MIPP
collected events of 120 GeV Main Injector protons striking a
target used in the NuMI facility at Fermilab. The data have been analyzed and
we present here charged pion yields per proton-on-target determined in bins of
longitudinal and transverse momentum between 0.5 and 80 GeV/c, with combined
statistical and systematic relative uncertainties between 5 and 10%.Comment: 15 pages, 13 figure
Characterisation of the muon beams for the Muon Ionisation Cooling Experiment
A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV/c, have emittances of approximately 1.2–2.3 π mm-rad horizontally and 0.6–1.0 π mm-rad vertically, a horizontal dispersion of 90–190 mm and momentum spreads of about 25 MeV/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE
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