Dynamic stability of space vehicles. Volume 8 - Atmospheric disturbances that affect flight control analysis

Space vehicle and control system dynamic response to atmospheric disturbance

A generalized virial theorem and the balance of kinetic and potential energies in the semiclassical limit

We obtain two-sided bounds on kinetic and potential energies of a bound state of a quantum particle in the semiclassical limit, as the Planck constant \hbar\ri 0. Proofs of these results rely on the generalized virial theorem obtained in the paper as well as on a decay of eigenfunctions in the classically forbidden region

Perturbation Theory of Schr\"odinger Operators in Infinitely Many Coupling Parameters

In this paper we study the behavior of Hamilton operators and their spectra which depend on infinitely many coupling parameters or, more generally, parameters taking values in some Banach space. One of the physical models which motivate this framework is a quantum particle moving in a more or less disordered medium. One may however also envisage other scenarios where operators are allowed to depend on interaction terms in a manner we are going to discuss below. The central idea is to vary the occurring infinitely many perturbing potentials independently. As a side aspect this then leads naturally to the analysis of a couple of interesting questions of a more or less purely mathematical flavor which belong to the field of infinite dimensional holomorphy or holomorphy in Banach spaces. In this general setting we study in particular the stability of selfadjointness of the operators under discussion and the analyticity of eigenvalues under the condition that the perturbing potentials belong to certain classes.Comment: 25 pages, Late

Producing Chart Data from Interferometric Sonars on Small AUVs

High frequency (100kHz to 500kHz) ‗interferometric‘ or phase measuring sonars are a common tool for boat-mounted hydrographic surveys. Recent improvements in sonar and positioning technology have led to improved data quality: 2005 saw the first interferometric survey accepted for charting by the UK Hydrographic office. In parallel with this there have been significant advances in man-portable autonomous underwater vehicles (AUVs). These technologies can be combined: there are now growing numbers of small AUVs running interferometric bathymetry surveys worldwide. The ability to access hazardous areas, provide cost-effective force-multiplication, and acquire higher resolution data from deeper water has proven very attractive.This paper discusses the influences on data quality when acquiring swath bathymetric data using interferometric sonars on small AUVs, including how the data can be processed and qualified for hydrographic charting. Commercial AUV capabilities are illustrated using data collected by a 7-inch diameter Gavia AUV (Teledyne Gavia, Iceland) carrying a 500kHz GeoSwath sonar (GeoAcoustics, UK). Error budgets are discussed, showing that existing technology is capable of achieving IHO S-44 Ed.5 Special Order surveys, within certain operational limits and using appropriate survey planning and data processing.Possible future improvements in data analysis methods are mentioned, including the use of SLAM (Simultaneous Localisation and Mapping) methods to improve navigation. This is illustrated using sample data processed in CleanSweep software (OIC Inc., Hawaii).Los sonares ―interferométricos‖ de alta frecuencia (100kHz a 500kHz) o que miden las fases son un instrumento común para los levantamientos hidrográficos montados en las barcas. Las mejoras recientes en tecnología han dado como resultado diferencias en la calidad de los datos: en el 2005 se aceptó el primer levantamiento interferométrico para su uso en cartografía por el Servicio Hidrográ-fico del Reino Unido. Paralelamente a esto ha habido mejoras en la tecnología portátil de Vehículos Submarinos Autónomos (AUV - Autonomous Underwater Vehicle). Hay ahora cada vez más cantidades de pequeños AUVs que efectúan levantamientos batimétricos en el mundo entero. La posibilidad de acceso a zonas peligrosas proporciona una multiplicación de las fuerzas rentable, y la adquisición de datos de una resolución mayor procedentes de aguas más profundas ha resultado muy atractiva.Este documento describe la ruta desde el vehículo lanzador a los datos que pueden ser cartografia-dos, concentrándose en el modo en el que los datos batimétricos de banda barrida adquiridos mediante sonares interferométricos en pequeños AUVs pueden ser procesados y aptos para la cartografía hidrográfica. Las capacidades de los AUVs comerciales se ilustran utilizando los datos recogidos con un AUV Gavia (Teledyne Gavia, Islandia) de 7 pulgadas de diámetro que transporta un sonar de barrido de 500kHz (de GeoAcoustics, RU). Se discuten los factores de error, que mues-tran que la tecnología existente puede llevar a cabo levantamientos de una Clase Especial según la Ed. 5 de la Norma S-44 de la OHI, dentro de ciertos límites operativos.Se mencionan las posibles mejoras futuras en los métodos de análisis de datos, incluyendo el uso de métodos de Localización y Cartografía Simultáneas (SLAM - Simultaneous Localisation and Map-ping) para mejorar la navegación. Esto se ilustra utilizando datos de muestras procesados en el pro-grama CleanSweep (OIC Inc., Hawaii).Les sonars ―interférométriques‖ à haute fréquence (de 100kHz à 500kHz) ou de mesure de phases sont un outil répandu pour la réalisation de levés hydrographiques à bord des navires. Des améliora-tions récentes dans le domaine de la technologie ont permis de faire des bonds en avant en matière de qualité des données. En 2005, le premier levé interférométrique a été agréé pour la cartographie par le Service hydrographique du Royaume-Uni. Il y a eu parallèlement des améliorations relatives à la technologie des véhicules sous-marins autonomes portables (AUV). Il existe maintenant un nombre croissant de petits AUV qui réalisent des levés bathymétriques dans le monde entier. La possibilité d‘accéder à des zones dangereuses, de multiplier les forces de façon rentable et d‘acquérir des données à plus haute résolution dans des eaux plus profondes s‘est révélée très intéressante.Ce document décrit le parcours suivi depuis la mise à la mer du véhicule jusqu‘aux données qui sont utilisées pour les cartes et se concentre sur la manière dont les données bathymétriques à large couverture acquises par sonars interférométriques à bord d‘AUV peuvent être traitées et admises pour la reproduction cartographique des données hydrographiques. Les capacités commerciales des AUV sont illustrées par les données recueillies par un AUV Gavia de 7 pouces de diamètre (Teledyne Gavia, Islande) embarquant un sonar GeoSwath de 500 kHz (GeoAcoustics, RU). Les budgets d‘erreur, qui montrent que la technologie existante est capable d‘obtenir des levés d’ordre spécial conformément à la 5ème édition de la publication S-44 de l’OHI dans le cadre de certaines limites opérationnelles, y sont discutés.De futurs progrès éventuels dans les méthodes d‘analyse des données sont mentionnés, y compris l‘utilisation de la méthode SLAM (Cartographie et localisation simultanée) afin d‘améliorer la navigation. Ceci est illustré par l‘exemple du traitement des données à l‘aide du logiciel CleanSweep software (OIC Inc., Hawaï)

Dynamical phase transition for a quantum particle source

We analyze the time evolution describing a quantum source for noninteracting particles, either bosons or fermions. The growth behaviour of the particle number (trace of the density matrix) is investigated, leading to spectral criteria for sublinear or linear growth in the fermionic case, but also establishing the possibility of exponential growth for bosons. We further study the local convergence of the density matrix in the long time limit and prove the semiclassical limit.Comment: 24 pages; In the new version, we added several references concerning open quantum systems and present an extended result on linear particle production in the fermionic cas

Long-Time Dynamics of Variable Coefficient mKdV Solitary Waves

We study the Korteweg-de Vries-type equation dt u=-dx(dx^2 u+f(u)-B(t,x)u), where B is a small and bounded, slowly varying function and f is a nonlinearity. Many variable coefficient KdV-type equations can be rescaled into this equation. We study the long time behaviour of solutions with initial conditions close to a stable, B=0 solitary wave. We prove that for long time intervals, such solutions have the form of the solitary wave, whose centre and scale evolve according to a certain dynamical law involving the function B(t,x), plus an H^1-small fluctuation.Comment: 19 page

Some remarks on quasi-Hermitian operators

A quasi-Hermitian operator is an operator that is similar to its adjoint in some sense, via a metric operator, i.e., a strictly positive self-adjoint operator. Whereas those metric operators are in general assumed to be bounded, we analyze the structure generated by unbounded metric operators in a Hilbert space. Following our previous work, we introduce several generalizations of the notion of similarity between operators. Then we explore systematically the various types of quasi-Hermitian operators, bounded or not. Finally we discuss their application in the so-called pseudo-Hermitian quantum mechanics.Comment: 18page

Protecting Ourselves from Harm: Voices of Aging Farmers

Senior farmers suffer the highest fatality risk of any age group in agriculture. The purpose of this exploratory study was to develop a voice for senior farmers by examining aging farmers\u27 and their families\u27 perspectives of farm work, associated injury risks, and methods to decrease those risks. Focus groups and personal interviews were used to collect data from 81 participants across seven U.S. states. The findings reflect the collective and verified voice of the study group. The Health Belief Model was applied and revealed differences between farmers and their family members; however, the need and desire to continue self-directed work was ubiquitous. Seniors reported external risks, while family members were more likely to name risks associated with the health of the senior farmer. Both groups cited stress as an injury risk. Posing risk to others was the trigger point for senior farmers to make behavior changes. Family members reported uneasiness in initiating safety conversations. Adaptation of existing interventions for self-assessment of risk was rejected. Use of the popular farm press and respected local resources were desired as avenues for safety education. Humor and stories were highly regarded. Interventions should be tailored for the target audience. These new insights into the risk perceptions of senior farmers and their families may result in more appropriate actions by health professionals, extension staff social workers, vocational rehabilitation specialists, and others who work with farm populations

Testing the Master Constraint Programme for Loop Quantum Gravity II. Finite Dimensional Systems

This is the second paper in our series of five in which we test the Master Constraint Programme for solving the Hamiltonian constraint in Loop Quantum Gravity. In this work we begin with the simplest examples: Finite dimensional models with a finite number of first or second class constraints, Abelean or non -- Abelean, with or without structure functions.Comment: 23 pages, no figure

Non-relativistic Lee Model on two Dimensional Riemannian Manifolds

This work is a continuation of our previous work (JMP, Vol. 48, 12, pp. 122103-1-122103-20, 2007), where we constructed the non-relativistic Lee model in three dimensional Riemannian manifolds. Here we renormalize the two dimensional version by using the same methods and the results are shortly given since the calculations are basically the same as in the three dimensional model. We also show that the ground state energy is bounded from below due to the upper bound of the heat kernel for compact and Cartan-Hadamard manifolds. In contrast to the construction of the model and the proof of the lower bound of the ground state energy, the mean field approximation to the two dimensional model is not similar to the one in three dimensions and it requires a deeper analysis, which is the main result of this paper.Comment: 18 pages, no figure