Abstract

Abstract

Abstract
The values of measured and calculated spectroscopic quantities of lithium niobate doped with rare earth and transition metal ions, such as polarized emission and absorption cross sections, variation of fluorescence life time with temperature and concentration of the dopant, Judd-Ofelt coefficients, non-radiative transition probabilities and energy levels are presented. Wherever published data is available, comparison with measured or calculated data presented in this work is carried out. The theories utilized in the interpretation of the experimental results, such as Judd-Ofelt theory, Fuchtbauer-Lademburg relation and McCumber theory are summarily presented.

Abstract
The interrogation of fiber Bragg grating sensors with multimode laser diodes is theoretically and experimentally analyzed using two different approaches: serrodyne and dithering techniques. It is also demonstrated that by using several laser modes it is possible to enhance the measurement range without compromising sensitivity, (C) 2000 Academic Press.

Abstract
This paper presents some of the developments we made with the goal of allowing a friendly control and simulation of a large number of autonomous agents based in behavior in interactive real-time systems. Our work has been specially oriented to the simulation and control of autonomous vehicles and pedestrians in the preparation of scenarios to driving simulation experiments in the DriS simulator. Because every element is intrinsically autonomous, only a few of them are usually addressed to implement the desired study event. Also, because our model is autonomous and controllable, we can use the same model in the implementation of both environment traffic and controlled vehicles. Our scripting language is based in Grafcet, a well known graphical language used in the specification and programming of industrial controllers. Our technique allows the imposition of both short time orders and long time goals to each autonomous element. Orders can be triggered reactively using sensors that monitor the state of virtual traffic and configurable timers that generate all the necessary Fixed and variable time events.

Abstract
It is known that neurons in the primary visual cortex are characterized by receptive fields that are selective for speciftc spatial orientations. It is believed that the sense of object motion and velocity are also related to these fields, as objects in natural scenes are represented by a sparse set of statistically independent components, such as edges. Currently, computational models of receptive fields consider only spatial components, and thus cannot account for time-varying sensory stimuli. In this paper, a model based on independent components analysis and cellular neural networks is proposed. This approach extends existing models to incorporate temporal aspects of sequences of images of natural scenes.