33,980 research outputs found
A study of the very high order natural user language (with AI capabilities) for the NASA space station common module
The requirements are identified for a very high order natural language to be used by crew members on board the Space Station. The hardware facilities, databases, realtime processes, and software support are discussed. The operations and capabilities that will be required in both normal (routine) and abnormal (nonroutine) situations are evaluated. A structure and syntax for an interface (front-end) language to satisfy the above requirements are recommended
Users Guide for SnadiOpt: A Package Adding Automatic Differentiation to Snopt
SnadiOpt is a package that supports the use of the automatic differentiation
package ADIFOR with the optimization package Snopt. Snopt is a general-purpose
system for solving optimization problems with many variables and constraints.
It minimizes a linear or nonlinear function subject to bounds on the variables
and sparse linear or nonlinear constraints. It is suitable for large-scale
linear and quadratic programming and for linearly constrained optimization, as
well as for general nonlinear programs. The method used by Snopt requires the
first derivatives of the objective and constraint functions to be available.
The SnadiOpt package allows users to avoid the time-consuming and error-prone
process of evaluating and coding these derivatives. Given Fortran code for
evaluating only the values of the objective and constraints, SnadiOpt
automatically generates the code for evaluating the derivatives and builds the
relevant Snopt input files and sparse data structures.Comment: pages i-iv, 1-2
A Primal-Dual Augmented Lagrangian
Nonlinearly constrained optimization problems can be solved by minimizing a sequence of simpler unconstrained or linearly constrained subproblems. In this paper, we discuss the formulation of subproblems in which the objective is a primal-dual generalization of the Hestenes-Powell augmented Lagrangian function. This generalization has the crucial feature that it is minimized with respect to both the primal and the dual variables simultaneously. A benefit of this approach is that the quality of the dual variables is monitored explicitly during the solution of the subproblem. Moreover, each subproblem may be regularized by imposing explicit bounds on the dual variables. Two primal-dual variants of conventional primal methods are proposed: a primal-dual bound constrained Lagrangian (pdBCL) method and a primal-dual 1 linearly constrained Lagrangian (pd1-LCL) method
Fisher information in quantum statistics
Braunstein and Caves (1994) proposed to use Helstrom's {\em quantum
information} number to define, meaningfully, a metric on the set of all
possible states of a given quantum system. They showed that the quantum
information is nothing else than the maximal Fisher information in a
measurement of the quantum system, maximized over all possible measurements.
Combining this fact with classical statistical results, they argued that the
quantum information determines the asymptotically optimal rate at which
neighbouring states on some smooth curve can be distinguished, based on
arbitrary measurements on identical copies of the given quantum system.
We show that the measurement which maximizes the Fisher information typically
depends on the true, unknown, state of the quantum system. We close the
resulting loophole in the argument by showing that one can still achieve the
same, optimal, rate of distinguishability, by a two stage adaptive measurement
procedure.
When we consider states lying not on a smooth curve, but on a manifold of
higher dimension, the situation becomes much more complex. We show that the
notion of ``distinguishability of close-by states'' depends strongly on the
measurement resources one allows oneself, and on a further specification of the
task at hand. The quantum information matrix no longer seems to play a central
role.Comment: This version replaces the previous versions of February 1999 (titled
'An Example of Non-Attainability of Expected Quantum Information') and that
of November 1999. Proofs and results are much improved. To appear in J. Phys.
Large dimensional classical groups and linear spaces
Suppose that a group has socle a simple large-rank classical group.
Suppose furthermore that acts transitively on the set of lines of a linear
space . We prove that, provided has dimension at least 25,
then acts transitively on the set of flags of and hence the
action is known. For particular families of classical groups our results hold
for dimension smaller than 25.
The group theoretic methods used to prove the result (described in Section 3)
are robust and general and are likely to have wider application in the study of
almost simple groups acting on finite linear spaces.Comment: 32 pages. Version 2 has a new format that includes less repetition.
It also proves a slightly stronger result; with the addition of our
"Concluding Remarks" section the result holds for dimension at least 2
MISAT: Designing a Series of Powerful Small Satellites Based upon Micro Systems Technology
MISAT is a research and development cluster which will create a small satellite platform based on Micro Systems Technology (MST) aiming at innovative space as well as terrestrial applications. MISAT is part of the Dutch MicroNed program which has established a microsystems infrastructure to fully exploit the MST knowledge chain involving public and industrial partners alike.
The cluster covers MST-related developments for the spacecraft bus and payload, as well as the satellite architecture. Particular emphasis is given to distributed systems in space to fully exploit the potential of miniaturization for future mission concepts. Examples of current developments are wireless sensor and actuator networks with plug and play characteristics, autonomous digital Sun sensors, re-configurable radio front ends with minimum power consumption, or micro-machined electrostatic accelerometer and gradiometer system for scientific research in fundamental physics as well as geophysics.
As a result of MISAT, a first nano-satellite will be launched in 2007 to demonstrate the next generation of Sun sensors, power subsystems and satellite architecture technology. Rapid access to in-orbit technology demonstration and verification will be provided by a series of small satellites. This will include a formation flying mission, which will increasingly rely on MISAT technology to improve functionality and reduce size, mass and power for advanced technology demonstration and novel scientific applications.
Behavioural compensatory adjustments to exercise training in overweight women
<b>Purpose:</b> To examine extent to which changes in non-exercise physical activity contribute to individual differences in body fat loss induced by exercise programs. <b>Methods:</b> Thirty four overweight/obese sedentary women (age: 31.7 +/- 8.1 years, BMI: 29.3 +/- 4.3 kg m-2) exercised for 8 weeks. Body composition, total energy expenditure (TEE), exercise EE (ExEE), activity EE (AEE) calculated as energy expenditure of all active activities minus ExEE, sedentary EE (SEDEE), sleeping EE (SEE), and energy intake were determined before and during the last week of the exercise intervention. <b>Results:</b> Over the 8-week exercise program net ExEE was 30.2 +/- 12.6 MJ and based on this, body fat loss was predicted to be 0.8 +/- 0.2 kg. For the group as a whole, change in body fat (-0.0 +/- 0.2 kg) was not significant but individual body fat changes ranged from -3.2 kg to +2.6 kg. Eleven participants achieved equal or more than the predicted body fat loss and were classified as 'Responders' and 23 subjects achieved less than the predicted fat loss and were classified as 'Non-responders'. In the group as a whole, daily TEE was increased by 0.62 +/- 0.30 MJ (p<0.05) and the change tended to be different between groups (Responders, +1.44 +/- 0.49 MJ; Non-responders, +0.29 +/- 0.36 MJ, p=0.08). Changes in daily AEE of Responders and Non-responders differed significantly between groups (Responders, +0.79 +/- 0.50 MJ; Non-responders, -0.62 +/- 0.39 MJ, p<0.05). There were no differences between Responders and Non-responders for changes in SEDEE and SEE or energy intake. <b>Conclusion:</b> Overweight and obese women who during exercise intervention achieve lower than predicted fat loss are compensating by being less active outside exercise sessions
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