11,872 research outputs found
Preliminary test results of a flight management algorithm for fuel conservative descents in a time based metered traffic environment
A flight management algorithm designed to improve the accuracy of delivering the airplane fuel efficiently to a metering fix at a time designated by air traffic control is discussed. The algorithm provides a 3-D path with time control (4-D) for a test B 737 airplane to make an idle thrust, clean configured descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path is calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithms and the results of the flight tests are discussed
Development and test results of a flight management algorithm for fuel conservative descents in a time-based metered traffic environment
A simple flight management descent algorithm designed to improve the accuracy of delivering an airplane in a fuel-conservative manner to a metering fix at a time designated by air traffic control was developed and flight tested. This algorithm provides a three dimensional path with terminal area time constraints (four dimensional) for an airplane to make an idle thrust, clean configured (landing gear up, flaps zero, and speed brakes retracted) descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithm is described. The results of the flight tests flown with the Terminal Configured Vehicle airplane are presented
Coherence of Associativity in Categories with Multiplication
The usual coherence theorem of MacLane for categories with multiplication
assumes that a certain pentagonal diagram commutes in order to conclude that
associativity isomorphisms are well defined in a certain practical sense. The
practical aspects include creating associativity isomorphisms from a given one
by tensoring with the identity on either the right or the left. We show, by
reinspecting MacLane's original arguments, that if tensoring with the identity
is restricted to one side, then the well definedness of constructed
isomorphisms follows from naturality only, with no need of the commutativity of
the pentagonal diagram. This observation was discovered by noting the
resemblance of the usual coherence theorems with certain properties of a
finitely presented group known as Thompson's group F. This paper is to be taken
as an advertisement for this connection.Comment: 8 pages, to appear in Journal of Pure and Applied Algebr
Cratering in low-density targets
Cratering in low density targets, and comparisons of various hypervelocity projectile-target combination
Presentations of higher dimensional Thompson groups
In a previous paper, we defined a higher dimensional analog of Thompson's
group V, and proved that it is simple, infinite, finitely generated, and not
isomorphic to any of the known Thompson groups. There are other Thompson groups
that are infinite, simple and finitely presented. Here we show that the new
group is also finitely presented by calculating an explicit finite
presentation.Comment: 35 pages, to appear in J. Algebr
The Algebra of Strand Splitting. II. A Presentation for the Braid Group on One Strand
Presentations are computed for a braided version BV of Thompson's group V and
for V itself showing that there is an Artin group/Coxeter group relation
between them. The presentation for V is obtained from that for BV by declaring
all that all generators are involutions.Comment: 15 page
The Algebra of Strand Splitting. I. A Braided Version of Thompson's Group V
We construct a braided version of Thompson's group V.Comment: 27 page
On small homotopies of loops
Two natural questions are answered in the negative:
(1) If a space has the property that small nulhomotopic loops bound small
nulhomotopies, then are loops which are limits of nulhomotopic loops themselves
nulhomotopic?
(2) Can adding arcs to a space cause an essential curve to become
nulhomotopic?
The answer to the first question clarifies the relationship between the
notions of a space being homotopically Hausdorff and -shape injective.Comment: 12 pages, 5 figure
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