An element being known quite nearly, to determine its correction by the collection of a great number of observations. Formation of the equations of condition. By disposing them in a manner that, in each of them, the coefficient of the correction of the element has the same sign, and adding them, we form a final equation which gives a mean correction. Expression of the probability that the error...

Estimation of escapement for steelhead trout (Oncorhynchus mykiss) from periodic visual counts of spawners is complicated by extreme changes in observer efficiency over the migration period, low numbers of fish, pulsed arrival timing, and variable survey life. We present a maximum likelihood method to compute escapement and uncertainty that accounts for these difficulties using mark–recapture d...

In order to support users to recover from erroneous changes or to explore previously executed modifications, collaborative editing systems offer the undo mechanism. Providing an undo feature in fully decentralised collaborative editors is challenging as users are allowed to revert any changes performed by any user. Operational transformation has been devised as a suitable mechanism for maintain...

We present and analyze an algorithm for the production of accurate digital elevation models (DEMs) using interferometric synthetic aperture radar (InSAR). The algorithm requires minimal manual intervention, as a result of using coarse or low-quality DEMs in the InSAR processing stream. The low-quality DEM data are used to estimate the relative geometry (baseline parameters) of the SAR systems. ...

This work is devoted to the numerical reliability and time requirements of the Mixed Finite Element (MFE) and Mixed-Hybrid Finite Element (MHFE) methods. The behavior of these methods is investigated under the influence of two factors: the mesh discretization and the medium heterogeneity. We show that, unlike the MFE, the MHFE ”suffers” with the presence of flatted triangular elements. A numeri...

Une approche bayésienne pour lesprobì emes inverses en imagerie Radarà synthèse d'ouverture Résumé L'imagerie Radarà Synthèse d'Ouverture (RSO) est une technique bien connue dans les domaines de télédétection, de surveillance aérienne, de géologie et de cartographie. Obtenir des images de haute résolution malgré la présence de bruit, tout en prenant en compte les caractéristiques des cibles dan...

Résumé On compare différentes méthodes d’estimation pour un modèle de régression non linéaire à variance paramétrée: les moindres carrés pondérés (MCP), les moindres carrés pondérés en deux étapes (MCP2), où l’estimateur des moindres carrés obtenu à la première étape sert à calculer la variance utilisée pour une estimation par MCP à la seconde étape, et enfin un estimateur des MCP avec des pond...

The problem of tracking a moving target with a nonholonomic mobile robot, by using sensor-based control techniques, is addressed. Two control design methods, relying on the transverse function approach, are proposed. For the first method, sensory signals are used to calculate an estimate of the relative pose of the robot with respect to the target. This estimate is then used for the calculation...