9,205 research outputs found
Determination of the Topology of a Directed Network
We consider strongly-connected directed networks of identical synchronous,
finite-state processors with in- and out-degree uniformly bounded by a network
constant. Via a straightforward extension of Ostrovsky and Wilkerson's
Backwards Communication Algorithm in [OW], we exhibit a protocol which solves
the Global Topology Determination Problem, the problem of having the root
processor map the global topology of a network of unknown size and topology,
with running time O(ND) where N represents the number of processors and D
represents the diameter of the network. A simple counting argument suffices to
show that the Global Topology Determination Problem has time-complexity Omega(N
logN) which makes the protocol presented asymptotically time-optimal for many
large networks.Comment: 9 pages, no figures, accepted to appear in IPDPS 2002 (unable to
attend), (journal version to appear in Information Processing Letters
Copyrights in Computer-Generated Works: Whom, if Anyone, Do We Reward?
Computer-generated works raise grave authorship concerns under U.S. copyright law, with arguments in favor of allocating copyrights to the computer user, programmer, the computer itself, or some combination therein. The author discusses the issues and paradoxes inherent in these choices, and assesses the nature of mathematical graphical processes in light of the idea/expression dichotomy
Quantum Modeling
We present a modification of Simon's algorithm that in some cases is able to
fit experimentally obtained data to appropriately chosen trial functions with
high probability. Modulo constants pertaining to the reliability and
probability of success of the algorithm, the algorithm runs using only
O(polylog(|Y|)) queries to the quantum database and O(polylog(|X|,|Y|))
elementary quantum gates where |X| is the size of the experimental data set and
|Y| is the size of the parameter space.We discuss heuristics for good
performance, analyze the performance of the algorithm in the case of linear
regression, both one-dimensional and multidimensional, and outline the
algorithm's limitations.Comment: 16 pages, 5 figures, in Proceedings, SPIE Conference on Quantum
Computation and Quantum Information, pp. 116-127, April 21-22, 200
Dynamic response and control of a jet-transport aircraft encountering a single-axis vortex
The dynamic responses of a jet-transport aircraft to two types of single-axis wind vortex encounters are studied. Aircraft attitude, flight path angle, and aerodynamic angle excursions are analyzed and dominating dynamic forcing effects are identified for each encounter. A simple departure-preventing LQR controller is designed to demonstrate the benefits of using automatic control to reduce the wind vortex hazard. A Proportional-Integral-Filter controller structure successfully regulates the critical parameters, roll angle, phi, and sideslip angle, beta, for the two different vortex encounters considered in this study
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