45,704 research outputs found
Expert systems for real-time monitoring and fault diagnosis
Methods for building real-time onboard expert systems were investigated, and the use of expert systems technology was demonstrated in improving the performance of current real-time onboard monitoring and fault diagnosis applications. The potential applications of the proposed research include an expert system environment allowing the integration of expert systems into conventional time-critical application solutions, a grammar for describing the discrete event behavior of monitoring and fault diagnosis systems, and their applications to new real-time hardware fault diagnosis and monitoring systems for aircraft
Electronic structure and resistivity of the double exchange model
The double exchange (DE) model with quantum local spins S is studied; an
equation of motion approach is used and decoupling approximations analogous to
Hubbard's are made. Our approximate one-electron Green function G is exact in
the atomic limit of zero bandwidth for all S and band filling n, and as n->0
reduces to a dynamical coherent potential approximation (CPA) due to Kubo; we
regard our approximation as a many-body generalisation of Kubo's CPA. G is
calculated self-consistently for general S in the paramagnetic state and for
S=1/2 in a state of arbitrary magnetization. The electronic structure is
investigated and four bands per spin are obtained centred on the atomic limit
peaks of the spectral function. A resistivity formula appropriate to the model
is derived from the Kubo formula and the paramagnetic state resistivity rho is
calculated; insulating states are correctly obtained at n=0 and n=1 for strong
Hund coupling. Our prediction for rho is much too small to be consistent with
experiments on manganites so we agree with Millis et al that the bare DE model
is inadequate. We show that the agreement with experiment obtained by Furukawa
is due to his use of an unphysical density of states.Comment: 20 pages, 8 figures, submitted to J. Phys.: Condens. Matte
Limb amputations in fixed dystonia: a form of body integrity identity disorder?
Fixed dystonia is a disabling disorder mainly affecting young women who develop fixed abnormal limb postures and pain after apparently minor peripheral injury. There is continued debate regarding its pathophysiology and management. We report 5 cases of fixed dystonia in patients who sought amputation of the affected limb. We place these cases in the context of previous reports of patients with healthy limbs and patients with chronic regional pain syndrome who have sought amputation. Our cases, combined with recent data regarding disorders of mental rotation in patients with fixed dystonia, as well as previous data regarding body integrity identity disorder and amputations sought by patients with chronic regional pain syndrome, raise the possibility that patients with fixed dystonia might have a deficit in body schema that predisposes them to developing fixed dystonia and drives some to seek amputation. The outcome of amputation in fixed dystonia is invariably unfavorable
The nature of the long time decay at a second order transition point
We show that at a second order phase transition, of \phi^4 like system, a
necessary condition for streched exponential decay of the time structure factor
is obeyed. Using the ideas presented in this proof a crude estimate of the
decay of the structure factor is obtained and shown to yield stretched
exponential decay under very reasonable conditions.Comment: 7 page
The Data Processing Pipeline for the Herschel-HIFI Instrument
The HIFI data processing pipeline was developed to systematically process
diagnostic, calibration and astronomical observations taken with the HIFI
science instrumentas part of the Herschel mission. The HIFI pipeline processed
data from all HIFI observing modes within the Herschel automated processing
environment, as well as, within an interactive environment. A common software
framework was developed to best support the use cases required by the
instrument teams and by the general astronomers. The HIFI pipeline was built on
top of that and was designed with a high degree of modularity. This modular
design provided the necessary flexibility and extensibility to deal with the
complexity of batch-processing eighteen different observing modes, to support
the astronomers in the interactive analysis and to cope with adjustments
necessary to improve the pipeline and the quality of the end-products. This
approach to the software development and data processing effort was arrived at
by coalescing the lessons learned from similar research based projects with the
understanding that a degree of foresight was required given the overall length
of the project. In this article, both the successes and challenges of the HIFI
software development process are presented. To support future similar projects
and retain experience gained lessons learned are extracted.Comment: 18 pages, 5 figure
Nucleon Structure from Lattice QCD
Recent advances in lattice field theory, in computer technology and in chiral
perturbation theory have enabled lattice QCD to emerge as a powerful
quantitative tool in understanding hadron structure. I describe recent progress
in the computation of the nucleon form factors and moments of parton
distribution functions, before proceeding to describe lattice studies of the
Generalized Parton Distributions (GPDs). In particular, I show how lattice
studies of GPDs contribute to building a three-dimensional picture of the
proton. I conclude by describing the prospects for studying the structure of
resonances from lattice QCD.Comment: 6 pages, invited plenary talk at NSTAR 2007, 5-8 September 2007,
Bonn, German
For Adults Only: Queer Theory Meets the Self and Identity in Adult Education
This article brings the perspective of Queer theory to the field of Adult Education as a way of examining critically the notions of self, identity, and sexuality as they have been taken for granted within the field. Adult Education, like most fields of practice and research, assumes the Western ideals of the monadic self, clear and undisputed identities, and heterosexuality. However, the intersection of a strong postmodern voice in both academia and the popular culture, the increasing exploration of other-than-hetero-sexualities in the media, and the foregrounding of sexuality in the work of adult education researchers (Brooks & Edwards,1997; Edwards, 1997; Hill,1995; Edwards, Grace, Henson, B., Henson, W., Hill, & Taylor, 1998; Tisdell & Taylor, 1995) forces the question of what relevance Queer theory has for adult educators
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