20 research outputs found
Dependable Embedded Systems
This Open Access book introduces readers to many new techniques for enhancing and optimizing reliability in embedded systems, which have emerged particularly within the last five years. This book introduces the most prominent reliability concerns from today’s points of view and roughly recapitulates the progress in the community so far. Unlike other books that focus on a single abstraction level such circuit level or system level alone, the focus of this book is to deal with the different reliability challenges across different levels starting from the physical level all the way to the system level (cross-layer approaches). The book aims at demonstrating how new hardware/software co-design solution can be proposed to ef-fectively mitigate reliability degradation such as transistor aging, processor variation, temperature effects, soft errors, etc. Provides readers with latest insights into novel, cross-layer methods and models with respect to dependability of embedded systems; Describes cross-layer approaches that can leverage reliability through techniques that are pro-actively designed with respect to techniques at other layers; Explains run-time adaptation and concepts/means of self-organization, in order to achieve error resiliency in complex, future many core systems
Selected topics in robotics for space exploration
Papers and abstracts included represent both formal presentations and experimental demonstrations at the Workshop on Selected Topics in Robotics for Space Exploration which took place at NASA Langley Research Center, 17-18 March 1993. The workshop was cosponsored by the Guidance, Navigation, and Control Technical Committee of the NASA Langley Research Center and the Center for Intelligent Robotic Systems for Space Exploration (CIRSSE) at RPI, Troy, NY. Participation was from industry, government, and other universities with close ties to either Langley Research Center or to CIRSSE. The presentations were very broad in scope with attention given to space assembly, space exploration, flexible structure control, and telerobotics
Software and hardware implementation techniques for digital communications-related algorithms
There are essentially three areas addressed in the body of this thesis. (a) The first is a theoretical investigation into the design and development of a practically realizable
implementation of a maximum-likelihood detection process to deal with digital data transmission over
HF radio links. These links exhibit multipath properties with delay spreads that can easily extend over 12
to 15 milliseconds. The project was sponsored by the Ministry of Defence through the auspices of the Science
and Engineering Research Council. The primary objective was to transmit voice band data at a minimum
rate of 2.4 kb/s continuously for long periods of time during the day or night. Computer simulation
models of HF propagation channels were created to simulate atmospheric and multipath effects of transmission
from London to Washington DC, Ankara, and as far as Melbourne, Australia. Investigations into
HF channel estimation are not the subject of this thesis. The detection process assumed accurate knowledge
of the channel. [Continues.
Recent Advances in Wireless Communications and Networks
This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters
NASA Tech Briefs, July 1993
Topics include: Data Acquisition and Analysis: Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences
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The application of artificial neural networks to interpret acoustic emissions from submerged arc welding
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Automated fusion welding processes play a fundamental role in modern manufacturing industries. The proliferation of joint geometries together with the large permutation of associated process variable configurations has given rise to research into complex system modelling and control strategies. Many of these techniques have involved monitoring of not only the electrical characteristics of the process but visual and acoustic information. Acoustic information derived from certain welding processes is well documented as it is an established fact that skilled manual welders utilise such information as an aid to creating an optimum weld. The experimental investigation presented in this thesis is dedicated to the feasibility of monitoring airborne acoustic emissions of Submerged Arc Welding (SAW) for diagnostic and real time control purposes. The experimental method adopted for this research takes a cybernetic approach to data processing and interpretation in an attempt to replicate the robustness of human biological functions. A custom designed audio hardware system was used to analyse signals obtained from bead on mild steel plate fusion welds. Time and frequency domains were used in an attempt to establish salient characteristics or identify the signatures associated with changes of the process variables. The featured parameters were voltage / current and weld travel speed, due to their ease of validation. However, consideration has also been given to weld defect prediction due to process instabilities. As the data proved to be highly correlated and erratic when subjected to off line statistical analysis, extensive investigation was given to the application of artificial neural networks to signal processing and real time control scenarios. As a consequence, a dedicated neural based software system was developed, utilising supervised and unsupervised neural techniques to monitor the process. The research was aimed at proving the feasibility of monitoring the electrical process parameters and stability of the welding process in real time. It was shown to be possible, by the exploitation of artificial neural networks, to generate a number of monitoring parameters indicative of the welding process state. The limitations of the present neural method and proposed developments are discussed, together with an overview of applied neural network technology and its impact on artificial intelligence and robotic control. Further developments are considered together with recommendations for future areas of research
NASA Tech Briefs, December 1988
This month's technical section includes forecasts for 1989 and beyond by NASA experts in the following fields: Integrated Circuits; Communications; Computational Fluid Dynamics; Ceramics; Image Processing; Sensors; Dynamic Power; Superconductivity; Artificial Intelligence; and Flow Cytometry. The quotes provide a brief overview of emerging trends, and describe inventions and innovations being developed by NASA, other government agencies, and private industry that could make a significant impact in coming years. A second bonus feature in this month's issue is the expanded subject index that begins on page 98. The index contains cross-referenced listings for all technical briefs appearing in NASA Tech Briefs during 1988
Satellite Networks: Architectures, Applications, and Technologies
Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled
Creating cohesive video with the narrative-informed use of ubiquitous wearable and imaging sensor networks
Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2010.Page 232 blank. Cataloged from PDF version of thesis.Includes bibliographical references (p. 222-231).In today's digital era, elements of anyone's life can be captured, by themselves or others, and be instantly broadcast. With little or no regulation on the proliferation of camera technology and the increasing use of video for social communication, entertainment, and education, we have undoubtedly entered the age of ubiquitous media. A world permeated by connected video devices promises a more democratized approach to mass-media culture, enabling anyone to create and distribute personalized content. While these advancements present a plethora of possibilities, they are not without potential negative effects, particularly with regard to privacy, ownership, and the general decrease in quality associated with minimal barriers to entry. This dissertation presents a first-of-its-kind research platform designed to investigate the world of ubiquitous video devices in order to confront inherent problems and create new media applications. This system takes a novel approach to the creation of user-generated, documentary video by augmenting a network of video cameras integrated into the environment with on-body sensing. The distributed video camera network can record the entire life of anyone within its coverage range and it will be shown that it, almost instantly, records more audio and video than can be viewed without prohibitive human resource cost.(cont.) This drives the need to develop a mechanism to automatically understand the raw audiovisual information in order to create a cohesive video output that is understandable, informative, and/or enjoyable to its human audience. We address this need with the SPINNER system. As humans, we are inherently able to transform disconnected occurrences and ideas into cohesive narratives as a method to understand, remember, and communicate meaning. The design of the SPINNER application and ubiquitous sensor platform is informed by research into narratology, in other words how stories are created from fragmented events. The SPINNER system maps low level sensor data from the wearable sensors to higher level social signal and body language information. This information is used to label the raw video data. The SPINNER system can then build a cohesive narrative by stitching together the appropriately labeled video segments. The results from three test runs are shown, each resulting in one or more automatically edited video piece. The creation of these videos is evaluated through review by their intended audience and by comparing the system to a human trying to perform similar actions. In addition, the mapping of the wearable sensor data to meaningful information is evaluated by comparing the calculated results to those from human observation of the actual video.by Mathew Laibowitz.Ph.D