Solid modeling interactive interface for design drafting

Providing certain Solid Modeling software systems with Computer-Aided Design Drafting facilities allows these systems to produce industry acceptable engineering drawing displays. A method is put forth to provide these facilities through the design and implemention of a two-dimensional interactive graphics package that interfaces with these systems. This allows other graphical and textual elements to be added to displays produced by the Solid Modeling systems

Bio-inspired log-polar based color image pattern analysis in multiple frequency channels

The main topic addressed in this thesis is to implement color image pattern recognition based on the lateral inhibition subtraction phenomenon combined with a complex log-polar mapping in multiple spatial frequency channels. It is shown that the individual red, green and blue channels have different recognition performances when put in the context of former work done by Dragan Vidacic. It is observed that the green channel performs better than the other two channels, with the blue channel having the poorest performance. Following the application of a contrast stretching function the object recognition performance is improved in all channels. Multiple spatial frequency filters were designed to simulate the filtering channels that occur in the human visual system. Following these preprocessing steps Dragan Vidacic\u27s methodology is followed in order to determine the benefits that are obtained from the preprocessing steps being investigated. It is shown that performance gains are realized by using such preprocessing steps

Collaborative Appearance-Based Place Recognition and Improving Place Recognition Using Detection of Dynamic Objects

This dissertation makes contributions to the problem of Long-Term Appearance-Based Place Recognition. We present a framework for place recognition in a collaborative scheme and a method to reduce the impact of dynamic objects on place representations. We demonstrate our findings using a state-of-the-art place recognition approach. We begin in Part I by describing the general problem of place recognition and its importance in applications where accurate localization is crucial. We discuss feature detection and description and also explain the functioning of several place recognition frameworks. In Part II, we present a novel framework for collaboration between agents from a pure appearance-based place recognition perspective. Using this framework, multiple agents can efficiently share partial or complete knowledge about places and benefit from their teamwork. This collaborative framework allows agents with limited storage and memory capacity to become useful in environment exploration tasks (for instance, by enabling remote recognition); includes procedures to manage an agent’s memory load and distributes knowledge of places across agents; allows the reuse of knowledge from one agent to another; and increases the tolerance for failure of individual agents. Part II also defines metrics which allow us to measure the performance of a system that uses the collaborative framework. Finally, in Part III, we present an innovative method to improve the recognition of places in environments densely populated by dynamic objects. We demonstrate that we can improve the recognition performance in these environments by incorporating high- level information from dynamic objects. Tests conducted using a synthetic dataset show the benefits of our approach. The proposed method allows the system to significantly improve the recognition performance in the photo-realistic dataset while reducing storage requirements, resulting in up to 23.7 percent less storage space than the state-of-the-art approach that we have extended; smaller representations also reduced the time required to match places. In Part III, we also formulate the concept of a valid place representation and determine the quality of the observation based on dynamic objects present in the agent’s view. Of course, recognition systems that are sensitive to dynamic objects incur additional computational costs to recognize those objects. We show that this additional cost is outweighed by the benefits that incorporating dynamic object detection in the place recognition pipeline. Our findings can be used in many applications, including applications for navigation, e.g. assisting visually impaired individuals with navigating indoors, or autonomous vehicles

Microwave brightness temperature and its relation to atmospheric general circulation features

August 1989.Includes bibliographical references.Sponsored by NSF ATM-8617856

Development, Evaluation and Validation of a Stereo Camera Underwater SLAM Algorithm

In this work the development of an algorithm for visual underwater localization is described. It spans the complete process from the initial idea, the development of a suitable underwater vehicle for testing to the algorithm's experimental validation in real underwater environments. Besides the development and validation of the visual SLAM algorithm, the methodology for its evaluation is a key aspect of this work. The resulting SURE-SLAM algorithm uses a stereo camera system and basic vehicle sensors (AHRS, DPS) to compute a complete, error-bounded localization solution for underwater vehicles in real-time with similar quality as state-of-the-art acoustically stabilized dead-reckoning approaches. The robustness of the algorithm as well as its limitations and failure-cases are established by extensive field testing with the AUV Dagon, which was developed during this thesis as test and evaluation vehicle

Analysis of BCNS and Newhope Key-exchange Protocols

Lattice-based cryptographic primitives are believed to offer resilience against attacks by quantum computers. Following increasing interest from both companies and government agencies in building quantum computers, a number of works have proposed instantiations of practical post-quantum key-exchange protocols based on hard problems in lattices, mainly based on the Ring Learning With Errors (R-LWE) problem. In this work we present an analysis of Ring-LWE based key-exchange mechanisms and compare two implementations of Ring-LWE based key-exchange protocol: BCNS and NewHope. This is important as NewHope protocol implementation outperforms state-of-the art elliptic curve based Diffie-Hellman key-exchange X25519, thus showing that using quantum safe key-exchange is not only a viable option but also a faster one. Specifically, this thesis compares different reconciliation methods, parameter choices, noise sampling algorithms and performance

Manned orbital systems concepts study. Book 3: Configurations for extended duration missions

Mission planning, systems analysis, and design concepts for the Space Shuttle/Spacelab system for extended manned operations are described. Topics discussed are: (1) payloads, (2) spacecraft docking, (3) structural design criteria, (4) life support systems, (5) power supplies, and (6) the role of man in long duration orbital operations. Also discussed are the assembling of large structures in space. Engineering drawings are included

Computational and algebraic aspects of two-dimensional, linear, multivariable control systems

There are at present a large number of theoretical and algorithmic results relating to one-variable polynomial matrices arising from one-dimensional multivariable systems. In recent years many of the theoretical results have been extended to two-variable polynomial matrices arising from two-dimensional multi variable systems, such as delay-differential or partial differential systems. However there has been no major attempt to extend the algorithmic results associated with single variable polynomial matrices to two-variable or multivariable polynomial matrices. This thesis investigates further some of the extensions of the algebra of one-dimensional multivariable systems to two-dimensional multivariable systems. [Continues.

Solar Probe: Report of the Science and Technology Definition Team

The Solar Probe mission of the Living With a Star program will be a historic mission, flying into one of the last unexplored regions of the solar system, the Sun's atmoshpere or corona, for the first time. Approaching as close as 3 Rs above the Sun's surface, Solar Probe will employ a combination of in-situ measurements and imaging to achieve the mission's primary scientific goal: to understand how the Sun's corona is heated and how the solar wind is accelerated. Solar Probe will revolutionize our knowledge of the physics of the origin and evolution of the solar wind. Moreover, by making the only direct, in-situ measurements of the region where some of the deadliest solar energetic particles are energized, Solar Probe will make unique and fundamental contributions to our ability to characterize and forecast the radiation environment in which future space explorers will work and live