10,483 research outputs found
Experiments with Ada
A 1200-line Ada source code project simulating the most basic functions of an operations control center was developed. We selected George Cherry's Process Abstraction Methodology for Embedded Large Applications (PAMELA) and DEC's Ada Compilation System (ACS) under VAX/VMS to build the software from requirements to acceptance test. The system runs faster than its FORTRAN implementation and was produced on schedule and under budget with an overall productivity in excess of 30 lines of Ada source code per day
Hamiltonian linearization of the rest-frame instant form of tetrad gravity in a completely fixed 3-orthogonal gauge: a radiation gauge for background-independent gravitational waves in a post-Minkowskian Einstein spacetime
In the framework of the rest-frame instant form of tetrad gravity, where the
Hamiltonian is the weak ADM energy , we define a special
completely fixed 3-orthogonal Hamiltonian gauge, corresponding to a choice of
{\it non-harmonic} 4-coordinates, in which the independent degrees of freedom
of the gravitational field are described by two pairs of canonically conjugate
Dirac observables (DO) , , . We define a Hamiltonian linearization of the
theory, i.e. gravitational waves, {\it without introducing any background
4-metric}, by retaining only the linear terms in the DO's in the
super-hamiltonian constraint (the Lichnerowicz equation for the conformal
factor of the 3-metric) and the quadratic terms in the DO's in . {\it We solve all the constraints} of the linearized theory: this
amounts to work in a well defined post-Minkowskian Christodoulou-Klainermann
space-time. The Hamilton equations imply the wave equation for the DO's
, which replace the two polarizations of the TT
harmonic gauge, and that {\it linearized Einstein's equations are satisfied} .
Finally we study the geodesic equation, both for time-like and null geodesics,
and the geodesic deviation equation.Comment: LaTeX (RevTeX3), 94 pages, 4 figure
L’invitation au voyage. Étude des configurations relationnelles dans les pages d’accueil de sites internet touristiques français
Variable Support Control for the Wave Equation: A Multiplier Approach
We study the controllability of the multidimensional wave equation in a
bounded domain with Dirichlet boundary condition, in which the support of the
control is allowed to change over time. The exact controllability is reduced to
the proof of the observability inequality, which is proven by a multiplier
method. Besides our main results, we present some applications
El espacio de lo provincial en el siglo XIX : memoria descriptiva sobre el Tucumán, de Juan Bautista Alberdi
Hacia el año 1834, Juan Bautista Alberdi regresa a su Tucumán natal, luego de una larga ausencia. En ese momento, instigado por el entonces gobernador, general Alejandro Heredia, redactó su Memoria descriptiva sobre el Tucumán, considerada el primer exponente de la literatura provincial en la Argentina. En este breve texto, de menos de treinta páginas, el escritor aúna a su perspectiva de extra-ambientado, de viajero, la del romántico y la del patriota, las cuales determinan las isotopías que lo estructuran. Este trabajo intenta rescatar del olvido tan valioso texto. Para ello se analizan la estructura, procedimientos y recursos que, estando al servicio de una intención precisamente manifestada por el autor, configuran una visión idealizada del terruño natal. El procedimiento descriptivo es el principal canal de textualización. A través de él, el autor ofrece una visión subjetiva, idealizadora y humanizada del paisaje para detenerse luego en la presentación del hombre tucumano, cuyo temperamento aparece determinado por la geografía de su entorno. Finalmente, Alberdi centra su mirada en los monumentos históricos; en este caso, su discurso materializa la confrontación entre lo que ve y lo que recuerda e identifica la vida de la patria con su propia vida.Towards 1834, Juan Bautista Alberdi returns to his native Tucuman after a long absence. At the request of the then governor General Alejandro Heredia, he wrote his Descriptive Memoir of Tucuman, which is considered the first example of provincial literature in Argentina. In this brief text, shorter than 30 pages, the author combines his perspec-tive of an extra- ambiented, a traveler, a romantic and a patriot, all of which determine the structuring isotopies. This paper aims at recovering from oblivion such a valuable text. The structure, procedure and figures are analyzed, considering that, at the service of a clear intention manifested by the author, they configure an idealized vision of the native land. The main process of textualization is decriptive. Through it, the writer offers a subjective, idealizing, and humanizing view of the landscape, to present then the man from Tucuman, whose temperament seems to be determined by the surrounding geography. Finally, Alberdi focuses on historical monuments; in this case, his discourse materializes the confrontation between what he sees and what he remembers; and identifies the homeland's life with his own.Fil: Agresti, Mabel Susana.
Universidad Nacional de Cuy
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