11,543 research outputs found
Microprocessor control of a wind turbine generator
A microprocessor based system was used to control the unattended operation of a wind turbine generator. The turbine and its microcomputer system are fully described with special emphasis on the wide variety of tasks performed by the microprocessor for the safe and efficient operation of the turbine. The flexibility, cost and reliability of the microprocessor were major factors in its selection
TDRSS momentum unload planning
A knowledge-based system is described which monitors TDRSS telemetry for problems in the momentum unload procedure. The system displays TDRSS telemetry and commands in real time via X-windows. The system constructs a momentum unload plan which agrees with the preferences of the attitude control specialists and the momentum growth characteristics of the individual spacecraft. During the execution of the plan, the system monitors the progress of the procedure and watches for unexpected problems
Theory of Linear Spin Wave Emission from a Bloch Domain Wall
We report an analytical theory of linear emission of exchange spin waves from
a Bloch domain wall, excited by a uniform microwave magnetic field. The problem
is reduced to a one-dimensional Schr\"odinger-like equation with a
P\"oschl-Teller potential and a driving term of the same profile. The emission
of plane spin waves is observed at excitation frequencies above a threshold
value, as a result of a linear process. The height-to-width aspect ratio of the
P\"oschl-Teller profile for a domain wall is found to correspond to a local
maximum of the emission efficiency. Furthermore, for a tailored P\"oschl-Teller
potential with a variable aspect ratio, particular values of the latter can
lead to enhanced or even completely suppressed emission.Comment: added ancillary file
Product and other fine structure in polynomial resolutions of mapping spaces
Let Map_T(K,X) denote the mapping space of continuous based functions between
two based spaces K and X. If K is a fixed finite complex, Greg Arone has
recently given an explicit model for the Goodwillie tower of the functor
sending a space X to the suspension spectrum \Sigma^\infty Map_T(K,X). Applying
a generalized homology theory h_* to this tower yields a spectral sequence, and
this will converge strongly to h_*(Map_T(K,X)) under suitable conditions, e.g.
if h_* is connective and X is at least dim K connected. Even when the
convergence is more problematic, it appears the spectral sequence can still
shed considerable light on h_*(Map_T(K,X)). Similar comments hold when a
cohomology theory is applied. In this paper we study how various important
natural constructions on mapping spaces induce extra structure on the towers.
This leads to useful interesting additional structure in the associated
spectral sequences. For example, the diagonal on Map_T(K,X) induces a
`diagonal' on the associated tower. After applying any cohomology theory with
products h^*, the resulting spectral sequence is then a spectral sequence of
differential graded algebras. The product on the E_\infty -term corresponds to
the cup product in h^*(Map_T(K,X)) in the usual way, and the product on the
E_1-term is described in terms of group theoretic transfers. We use explicit
equivariant S-duality maps to show that, when K is the sphere S^n, our
constructions at the fiber level have descriptions in terms of the
Boardman-Vogt little n-cubes spaces. We are then able to identify, in a
computationally useful way, the Goodwillie tower of the functor from spectra to
spectra sending a spectrum X to \Sigma ^\infty \Omega ^\infty X.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-28.abs.htm
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