496,164 research outputs found
Satellite auxiliary propulsion systems
Report is announced which describes techniques for selecting optimum system for specific satellite mission. Descriptions of propulsion systems are presented along with illustrations and diagrams. Report contains references, cost-effectiveness techniques, and reliability measurements and estimates
Probabilistic cloning with supplementary information contained in the quantum states of two auxiliary systems
In probabilistic cloning with two auxiliary systems, we consider and compare
three different protocols for the success probabilities of cloning. We show
that, in certain circumstances, it may increase the success probability to add
an auxiliary system to the probabilistic cloning machine having one auxiliary
system, but we always can find another cloning machine with one auxiliary
system having the same success probability as that with two auxiliary systems.Comment: 18 page
Secure Communication using Compound Signal from Generalized Synchronizable Chaotic Systems
By considering generalized synchronizable chaotic systems, the
drive-auxiliary system variables are combined suitably using encryption key
functions to obtain a compound chaotic signal. An appropriate feedback loop is
constructed in the response-auxiliary system to achieve synchronization among
the variables of the drive-auxiliary and response-auxiliary systems. We apply
this approach to transmit analog and digital information signals in which the
quality of the recovered signal is higher and the encoding is more secure.Comment: 7 pages (7 figures) RevTeX, Please e-mail Lakshmanan for figures,
submitted to Phys. Lett. A (E-mail: [email protected]
Secondary electric power generation with minimum engine bleed
Secondary electric power generation with minimum engine bleed is discussed. Present and future jet engine systems are compared. The role of auxiliary power units is evaluated. Details of secondary electric power generation systems with and without auxiliary power units are given. Advanced bleed systems are compared with minimum bleed systems. A cost model of ownership is given. The difference in the cost of ownership between a minimum bleed system and an advanced bleed system is given
New Approach to Duality-Invariant Nonlinear Electrodynamics
We survey a new approach to the duality-invariant systems of nonlinear
electrodynamics, based on introducing auxiliary bi-spinor fields. In this
approach, the entire information about the given self-dual system is encoded in
the U(1) invariant interaction of the auxiliary fields, while the standard
self-dual Lagrangians appear on shell as a result of eliminating auxiliary
fields by their equations of motion. Starting from the simplest U(1) duality,
we show how this approach can be generalized to the U(N) duality (with N
independent Maxwell field strengths), as well as to self-dual systems of {\cal
N}=1 supersymmetric electrodynamics. Also, it works perfectly for self-dual
systems with higher derivatives in the action.Comment: 13 pages, Talk given by E. Ivanov at the conference "Integrable
Systems and Quantum Symmetries", Prague, June 11 - 16, 201
Identification of Stochastic Wiener Systems using Indirect Inference
We study identification of stochastic Wiener dynamic systems using so-called
indirect inference. The main idea is to first fit an auxiliary model to the
observed data and then in a second step, often by simulation, fit a more
structured model to the estimated auxiliary model. This two-step procedure can
be used when the direct maximum-likelihood estimate is difficult or intractable
to compute. One such example is the identification of stochastic Wiener
systems, i.e.,~linear dynamic systems with process noise where the output is
measured using a non-linear sensor with additive measurement noise. It is in
principle possible to evaluate the log-likelihood cost function using numerical
integration, but the corresponding optimization problem can be quite intricate.
This motivates studying consistent, but sub-optimal, identification methods for
stochastic Wiener systems. We will consider indirect inference using the best
linear approximation as an auxiliary model. We show that the key to obtain a
reliable estimate is to use uncertainty weighting when fitting the stochastic
Wiener model to the auxiliary model estimate. The main technical contribution
of this paper is the corresponding asymptotic variance analysis. A numerical
evaluation is presented based on a first-order finite impulse response system
with a cubic non-linearity, for which certain illustrative analytic properties
are derived.Comment: The 17th IFAC Symposium on System Identification, SYSID 2015,
Beijing, China, October 19-21, 201
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