52,483 research outputs found
Leeds Met Library Facebook application
At the Leeds Met staff development festival in 2008 a library graduate trainee, Anna Hepworth, took part in a ‘Dragons’ Den’ event which saw staff propose new, innovative ideas to a panel of senior managers. Anna’s suggestion was to develop a Facebook application (or ‘app’) for the library and it was one of the competition winners. Anna’s initial proposal was to create a Leeds Met library catalogue application, but after discussions with members of the library’s ‘technologies for learning’ team it was decided to take the application a stage further, creating a mash-up using data from the library management system (Sirsi-Dynix Symphony). The Facebook application would send a library catalogue search box to a Facebook profile, but would also add value by delivering customised user data, including library record details such as number of issues, reservations and overdues. There would also be links to the library website and online self-service functions from the application
The Optimum Distance at which to Determine the Size of a Giant Air Shower
To determine the size of an extensive air shower it is not necessary to have
knowledge of the function that describes the fall-off of signal size from the
shower core (the lateral distribution function). In this paper an analysis with
a simple Monte Carlo model is used to show that an optimum ground parameter can
be identified for each individual shower. At this optimal core distance,
, the fluctuations in the expected signal, ,
due to a lack of knowledge of the lateral distribution function are minimised.
Furthermore it is shown that the optimum ground parameter is determined
primarily by the array geometry, with little dependence on the energy or zenith
angle of the shower or choice of lateral distribution function. For an array
such as the Pierre Auger Southern Observatory, with detectors separated by 1500
m in a triangular configuration, the optimum distance at which to measure this
characteristic signal is close to 1000 m
Challenges with bearings only tracking for missile guidance systems and how to cope with them.
This paper addresses the problem of closed loop missile guidance using bearings and target angular extent information. Comparison is performed between particle filtering methods and derivative free methods. The extent information characterizes target size and we show how this can help compensate for observability problems. We demonstrate that exploiting angular extent information improves filter estimation accuracy. The performance of the filters has been studied over a testing scenario with a static target, with respect to accuracy, sensitivity to perturbations in initial conditions and in different seeker modes (active, passive and semi-active)
Executive computer program for linking independent computer programs: ODINEX
Program controls sequence of execution of network of program elements and maintains data base of common information which forms communication link among them. Approach is applicable to any multiple-program task
Patents from government-financed research and development
Data on numbers, sources, and kinds of patented inventions from government financed research and developmen
Symmetries of quasiplatonic Riemann surfaces
We state and prove a corrected version of a theorem of Singerman, which
relates the existence of symmetries (anticonformal involutions) of a
quasiplatonic Riemann surface (one uniformised by a normal
subgroup of finite index in a cocompact triangle group ) to the
properties of the group . We give examples to illustrate the
revised necessary and sufficient conditions for the existence of symmetries,
and we relate them to properties of the associated dessins d'enfants, or
hypermaps
Dynamic performance of detuned ridge waveguide AlInGaAs distributed feedback laser diodes
The dynamic behavior of AlInGaAs ridge waveguide distributed feedback lasers is reported in this work covering five detuned wavelengths between 1291 nm and 1326 nm for a laser active layer optical peak gain design centered at 1310 nm at room temperature. The detuning is achieved by modifying the laser grating pitch that performs the mode selection within the laser cavity simultaneously across a single processed wafer. The dynamic behavior is evaluated using the resonance frequencies of the detuned lasers measured at a range of injection currents for heatsink temperatures of 25°C and 85°C. The results confirm that a speed improvement can be achieved at 25°C by detuning the laser to shorter wavelengths. However, the results also show that a lower direct modulation bandwidth at 85°C makes the shorter wavelength design less attractive. For communications applications such as 10 Gbps uncooled operation, this trade-off between detuning and modulation bandwidth imply an optimum around −2 nm to +8 nm detuning (measured at 25°C)
Bessel beam propagation: Energy localization and velocity
The propagation of a Bessel beam (or Bessel-X wave) is analyzed on the basis
of a vectorial treatment. The electric and magnetic fields are obtained by
considering a realistic situation able to generate that kind of scalar field.
Specifically, we analyze the field due to a ring-shaped aperture over a
metallic screen on which a linearly polarized plane wave impinges. On this
basis, and in the far field approximation, we can obtain information about the
propagation of energy flux and the velocity of the energy.Comment: 6 pages, 4 figure
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