340 research outputs found
Applications of satellite data relay to problems of field seismology
A seismic signal processor was developed and tested for use with the NOAA-GOES satellite data collection system. Performance tests on recorded, as well as real time, short period signals indicate that the event recognition technique used is nearly perfect in its rejection of cultural signals and that data can be acquired in many swarm situations with the use of solid state buffer memories. Detailed circuit diagrams are provided. The design of a complete field data collection platform is discussed and the employment of data collection platforms in seismic network is reviewed
Advanced sensors technology survey
This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed
Inaudible acoustics: Techniques and applications
This dissertation is focused on developing a sub-area of acoustics that we call inaudible acoustics. We have developed two core capabilities, (1) BackDoor and (2) Ripple, and demonstrated their use in various mobile and IoT applications. In BackDoor, we synthesize ultrasound signals that are inaudible to humans yet naturally recordable by all microphones. Importantly, the microphone does not require any modification, enabling billions of microphone-enabled devices, including phones, laptops, voice assistants, and IoT devices, to leverage the capability. Example applications include acoustic data beacons, acoustic watermarking, and spy-microphone jamming. In Ripple, we develop modulation and sensing techniques for vibratory signals that traverse through solid surfaces, enabling a new form of secure proximal communication. Applications of the vibratory communication system include on-body communication through imperceptible physical vibrations and device-device secure data transfer through physical contacts. Our prototypes include an inaudible jammer that secures private conversations from electronic eavesdropping, acoustic beacons for location-based information sharing, and vibratory communication in a smart-ring sending password through a finger touch. Our research also uncovers new security threats to acoustic devices. While simple abuse of inaudible jammer can disable hearing aids and cell phones, our work shows that voice interfaces, such as Amazon Echo, Google Home, Siri, etc., can be compromised through carefully designed inaudible voice commands. The contributions of this dissertation can be summarized in three primitives: (1) exploiting inherent hardware nonlinearity for sensing out-of-band signals, (2) developing the vibratory communication system for secure touch-based data exchange, and (3) structured information reconstruction from noisy acoustic signals. In developing these primitives, we draw from principles in wireless networking, digital communications, signal processing, and embedded design and translate them to completely functional systems
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
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Short Distance Telemetry for Piston Monitoring. Design and Development of Short Distance Telemetry for Engine Condition Monitoring.
Piston telemetry research involves monitoring the temperatures at specific internal location points within a combustion engine piston. The temperatures are detected with type K thermocouples as voltages and processed to convert them into temperatures using cold junction compensation methods.
The present system uses a specific sensor designed to operate in the high temperature environment within the piston, reading multiple thermocouples. Because of the reciprocating motion of the piston, power generation is intermittent and available only when the piston reaches near bottom dead centre, using inductive coupling to power the sensors and transmit data to an evaluation unit for data processing.
The planned system involves designing and building a prototype telemetry unit using ¿off the shelf¿ components that integrate the reading of thermocouple outputs, signal processing and cold junction compensation. Wireless telemetry is adopted for data transmission with an integrated Bluetooth and microcontroller module. The data acquisition module can be adapted for other sensors by adapting the firmware uploaded to the microcontroller. The hardware electronics are envisaged to be encased in thermal insulation to enable operation in high temperature environments.
The considered system requires a power supply for the integrated components in the form of a power generator and that it should meet two criteria: to be located within confined spaces and to be permanently available, without having to dismantle systems to change batteries. The selected method is an induction generator constructed from a coil stator connected to the piston connection rod big end and a permanent magnet rotor connected to the crankshaft.
The suggested mechatronic system is validated against the present system by comparing both systems to determine whether wireless telemetry can perform within acceptable tolerances and limits for the specified task. Then, for acceptable performances, reduce costs and include flexibility to operate in multiple environments. Bench testing shows that the power generator is capable of driving the sensors and the Bluetooth integrated DAQ system.EPSRC and University of Bradfor
OBSERVER-BASED-CONTROLLER FOR INVERTED PENDULUM MODEL
This paper presents a state space control technique for inverted pendulum system. The system is a common classical control problem that has been widely used to test multiple control algorithms because of its nonlinear and unstable behavior. Full state feedback based on pole placement and optimal control is applied to the inverted pendulum system to achieve desired design specification which are 4 seconds settling time and 5% overshoot. The simulation and optimization of the full state feedback controller based on pole placement and optimal control techniques as well as the performance comparison between these techniques is described comprehensively. The comparison is made to choose the most suitable technique for the system that have the best trade-off between settling time and overshoot. Besides that, the observer design is analyzed to see the effect of pole location and noise present in the system
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