Visibility-Related Problems on Parallel Computational Models

Visibility-related problems find applications in seemingly unrelated and diverse fields such as computer graphics, scene analysis, robotics and VLSI design. While there are common threads running through these problems, most existing solutions do not exploit these commonalities. With this in mind, this thesis identifies these common threads and provides a unified approach to solve these problems and develops solutions that can be viewed as template algorithms for an abstract computational model. A template algorithm provides an architecture independent solution for a problem, from which solutions can be generated for diverse computational models. In particular, the template algorithms presented in this work lead to optimal solutions to various visibility-related problems on fine-grain mesh connected computers such as meshes with multiple broadcasting and reconfigurable meshes, and also on coarse-grain multicomputers. Visibility-related problems studied in this thesis can be broadly classified into Object Visibility and Triangulation problems. To demonstrate the practical relevance of these algorithms, two of the fundamental template algorithms identified as powerful tools in almost every algorithm designed in this work were implemented on an IBM-SP2. The code was developed in the C language, using MPI, and can easily be ported to many commercially available parallel computers

(1) time Parallel Agorithm for Finding 2D Convex Hull on a Reconfigurable Mesh Computer Architecture

In this paper we propose a parallel algorithm in image processing in (1) time, intended for a parallel machine '' Reconfigurable Mesh Computer (RMC), of size n x n Elementary Processors (PE). The algorithm consists in determining the convex envelope of a two-level 2D image with a complexity in (1) time. The approach used is purely geometric. It is based solely on the projection of the coordinates of PEs retained in specific quadrants and on the application of the algorithm that determines the Min / Max in (1) time. This has reduced the complexity of the algorithm for determining the convex hull at (1) time

Geometric modeling for computer aided design

The primary goal of this grant has been the design and implementation of software to be used in the conceptual design of aerospace vehicles particularly focused on the elements of geometric design, graphical user interfaces, and the interaction of the multitude of software typically used in this engineering environment. This has resulted in the development of several analysis packages and design studies. These include two major software systems currently used in the conceptual level design of aerospace vehicles. These tools are SMART, the Solid Modeling Aerospace Research Tool, and EASIE, the Environment for Software Integration and Execution. Additional software tools were designed and implemented to address the needs of the engineer working in the conceptual design environment. SMART provides conceptual designers with a rapid prototyping capability and several engineering analysis capabilities. In addition, SMART has a carefully engineered user interface that makes it easy to learn and use. Finally, a number of specialty characteristics have been built into SMART which allow it to be used efficiently as a front end geometry processor for other analysis packages. EASIE provides a set of interactive utilities that simplify the task of building and executing computer aided design systems consisting of diverse, stand-alone, analysis codes. Resulting in a streamlining of the exchange of data between programs reducing errors and improving the efficiency. EASIE provides both a methodology and a collection of software tools to ease the task of coordinating engineering design and analysis codes

Design Optimization of Folding Solar Powered Autonomous Underwater Vehicles Using Origami Structure

Origami, as an application for morphing structure engineering, which has been studied for a long time, has recently made remarkable progress in terms of technology. The most distinctive feature of this technology is the presence of two types, flat mode and folded mode. The origami algorithm enables the conversion of these two modes based on the mathematical formulations. Completion of this algorithm now means that origami is part of the design process and can be applied to applications. This thesis demonstrates a design process for origami-inspired morphing structures that transform between a flat configuration and a folded convex shape. There are many obstacles in the development of the design process. In particular, consideration should be given to the surface difference of the flat configuration and the folded convex mode. In this thesis, I introduce the design process which takes into consideration the origami structure design deeply. To demonstrate this process, I have selected an application which is emerging and interesting, that is, unmanned vehicles. Especially, the design of Autonomous Underwater Vehicles (AUVs) is a difficult challenge since it requires the consideration of various aspects such as mission range, controllability, energy source, and carrying capacity. The Predictive Parameterized Pareto Genetic Algorithm (P3GA) is selected as the optimization method to determine a parameterized Pareto frontier of design options with desired characteristics for a variety of missions for the AUV