Abstract

Abstract
Given C-2 infinitely renormalizable unimodal maps f and g with a quadratic critical point and the same bounded combinatorial type, we prove that they are C1+alpha conjugate along the closure of the corresponding forward orbits of the critical points, for some alpha > 0.

Abstract
This paper describes the mission control software used in the LSTS/FEUP underwater vehicles. This software follows the guidelines of the generalized vehicle architecture [1], adapts the original idea to encompass the current application requirements and constitutes a first implementation. The work is focused on the design and implementation of an application that can be easily adapted to different vehicle configurations or even to different vehicles. One of the desired goals was to enhance software reusability and to establish a development environment that allows developers with a minimal knowledge of coding details to upgrade the application. To assist this purpose, a CASE tool, which provides modern software development techniques, was used. A simulation environment was also developed whose purpose is to test the applications and to detect possible malfunctions before they occur during mission execution.

Abstract
This paper proposes a design of a sliding mode controller for direct torque control of an induction motor drive. The design includes the hardware structure, the control laws for torque control and rotor flux control. The modulation is defined as part of the variable structure control algorithm which enables an optimum choice of output voltage of the static converter. The validity and robustness of the proposed control system were verified by simulation. The simulation results are presented to demonstrate their agreement with theoretical predictions of the proposed controller. Copyright (C) 1998 IFAC.

Abstract

Abstract
This paper presents a description of the image generation sub-system developed to allow the presentation of realistic visual feedback in interactive visual simulation with large scene databases. The developed image generator applies all the standard state-of-art image generation algorithms aimed to real-time interactive simulation. Some of these important algorithms are also explained in this document. I addition, some innovative optimization techniques like the hierarchical back face rejection of objects, the visibility preprocessing and the automatic optimization of levels-of-detail are being developed and detailed in this paper. These techniques will allow a better use of any image generation system and improve significantly the visualization of huge scene databases even in high-end graphics architectures.