Numerical implications of stabilization by the use of integrals

Liapunov or energy restraint methods for dynamic stabilization in two body motion perturbation problems are considered. Results of computerized orbital stabilization estimates show that the application of energy restraint prevents the occurrence of consistent timing errors in the stepwise integration of equations of motion for a nearly circular orbit

Context dependent prediction and category encoding for DPCM image compression

Efficient compression of image data requires the understanding of the noise characteristics of sensors as well as the redundancy expected in imagery. Herein, the techniques of Differential Pulse Code Modulation (DPCM) are reviewed and modified for information-preserving data compression. The modifications include: mapping from intensity to an equal variance space; context dependent one and two dimensional predictors; rationale for nonlinear DPCM encoding based upon an image quality model; context dependent variable length encoding of 2x2 data blocks; and feedback control for constant output rate systems. Examples are presented at compression rates between 1.3 and 2.8 bits per pixel. The need for larger block sizes, 2D context dependent predictors, and the hope for sub-bits-per-pixel compression which maintains spacial resolution (information preserving) are discussed

LAMMR world data base documentation support and demonstrations

The primary purpose of the World Surface Map is to provide the LAMMR subsystem with world surface type classifications that are used to set up LAMMR LEVEL II process control. This data base will be accessed solely by the LAMMR subsystem. The SCATT and ALT subsystems will access the data base indirectly through the T sub b (Brightness Temperature) Data Bank, where the surface types were updated from a priori to current classification, and where the surface types were organized on an orbital subtrack basis. The single most important factor in the design of the World Surface Maps is the ease of access to the information while the complexity of generating these maps is of lesser importance because their generation is a one-time, off-line process. The World Surface Map provides storage of information with a resolution of 7 km necessary to set flags concerning the earth's features with a different set of maps for each month of the year

An automated approach to the design of decision tree classifiers

The classification of large dimensional data sets arising from the merging of remote sensing data with more traditional forms of ancillary data is considered. Decision tree classification, a popular approach to the problem, is characterized by the property that samples are subjected to a sequence of decision rules before they are assigned to a unique class. An automated technique for effective decision tree design which relies only on apriori statistics is presented. This procedure utilizes a set of two dimensional canonical transforms and Bayes table look-up decision rules. An optimal design at each node is derived based on the associated decision table. A procedure for computing the global probability of correct classfication is also provided. An example is given in which class statistics obtained from an actual LANDSAT scene are used as input to the program. The resulting decision tree design has an associated probability of correct classification of .76 compared to the theoretically optimum .79 probability of correct classification associated with a full dimensional Bayes classifier. Recommendations for future research are included

Context sensitive formulations of antenna pattern correction and side lobe compensation for NOSS/LAMMR real time processing

Large antenna multi-channel microwave radiometer (LAMMR) software specifications were written for LAMMR ground processing. There is a need to determine more computationally-efficient antenna temperature correction methods in compensating side lobe contributions especially near continents, islands and weather fronts. One of the major conclusions was that the antenna pattern corrections (APC) processes did not accomplish the implied goals of compensating for the antenna side lobe influences on brightness temperature. A-priori knowledge of land/water locations was shown to be needed and had to be incorporated in a context sensitive APC process if the artifacts caused by land presence is to be avoided. The high temperatures in land regions can severely bias the lower ocean response

Rhétorique lexicale, polyphonie et argument d’autorité : une analyse de cas

Nous nous intéresserons ici aux procédés de langage et à leur rôle dans la prise en charge énonciative du discours. Ces procédés consistent à produire du sens en s’appuyant spécifiquement sur les possibilités de substitutions des ressources lexicales de la langue (plutôt que sur leur mise en discours) et servent à constituer des paradigmes désignationnels, qui vont servir de supports aux jugements. À partir d’un article intitulé « Autopsie d’une mini-crise » (Le Devoir, 11 juillet 1998, p. A9), nous nous attardons spécifiquement aux procédés lexicaux par lesquels l’énonciateur gère les voix énonciatives de manière à consolider un argument d’autorité sur lequel toute son argumentation est fondée.This paper investigates language procedures and their role in bearing the enunciative weight of discourse. These procedures enable meaning to be produced by emphasizing the possibility of substitution of the language's lexical resources (rather than their discursive use); they serve to construct the designational paradigms that will support the judgments being made. Basing our study on an article entitled "Autopsie d’une mini-crise" (from Le Devoir, July 11, 1998, p. A9), we will explore the lexical procedures through which the enunciator manages the enunciative voices in the text, so as to construct a fallacious appeal to authority on which his entire argument is based