633 research outputs found
Applications of optical processing for improving ERTS data, volume 1
Application of optically diagnosed noise information toward development of filtering subroutines for improvement of digital sensing data tape quality - Vol.
Estimating Movement from Mobile Telephony Data
Mobile enabled devices are ubiquitous in modern society. The information gathered by
their normal service operations has become one of the primary data sources used in the
understanding of human mobility, social connection and information transfer. This thesis
investigates techniques that can extract useful information from anonymised call detail records
(CDR). CDR consist of mobile subscriber data related to people in connection with the network
operators, the nature of their communication activity (voice, SMS, data, etc.), duration of the
activity and starting time of the activity and servicing cell identification numbers of both the
sender and the receiver when available.
The main contributions of the research are a methodology for distance measurements
which enables the identification of mobile subscriber travel paths and a methodology for
population density estimation based on significant mobile subscriber regions of interest. In
addition, insights are given into how a mobile network operator may use geographically located
subscriber data to create new revenue streams and improved network performance. A range of
novel algorithms and techniques underpin the development of these methodologies. These
include, among others, techniques for CDR feature extraction, data visualisation and CDR data
cleansing.
The primary data source used in this body of work was the CDR of Meteor, a mobile
network operator in the Republic of Ireland. The Meteor network under investigation has just
over 1 million customers, which represents approximately a quarter of the country’s 4.6 million
inhabitants, and operates using both 2G and 3G cellular telephony technologies.
Results show that the steady state vector analysis of modified Markov chain mobility
models can return population density estimates comparable to population estimates obtained
through a census. Evaluated using a test dataset, results of travel path identification showed
that developed distance measurements achieved greater accuracy when classifying the routes
CDR journey trajectories took compared to traditional trajectory distance measurements.
Results from subscriber segmentation indicate that subscribers who have perceived similar
relationships to geographical features can be grouped based on weighted steady state mobility
vectors. Overall, this thesis proposes novel algorithms and techniques for the estimation of
movement from mobile telephony data addressing practical issues related to sampling, privacy
and spatial uncertainty
Resonant Tunnelling Optoelectronic Circuits
Nowadays, most communication networks such as local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs) have replaced or are about to replace coaxial cable or twisted copper wire with fiber optical cables. Light-wave communication systems comprise a transmitter based on a visible or near-infrared light source, whose carrier is modulated by the information signal to be transmitted, a transmission media such as an optical fiber, eventually utilizing in-line optical amplification, and a receiver based on a photo-detector that recovers the information signal (Liu, 1996)(Einarsson, 1996). The transmitter consists of a driver circuit along a semiconductor laser or a light emitting diode (LED). The receiver is a signal processing circuit coupled to a photo-detector such as a photodiode, an avalanche photodiode (APD), a phototransistor or a high speed photoconductor that processes the photo-detected signal and recovers the primitive information signa
Software defined wireless network (sdwn) for industrial environment: case of underground mine
Avec le développement continu des industries minières canadiennes, l’établissement des réseaux de communications souterrains avancés et sans fil est devenu un élément essentiel du processus industriel minier et ceci pour améliorer la productivité et assurer la communication entre les mineurs. Cette étude vise à proposer un système de communication minier en procurant une architecture SDWN (Software Defined Wireless Network) basée sur la technologie de communication LTE. Dans cette étude, les plateformes les plus importantes de réseau mobile 4G ont été étudiées, configurées et testées dans deux zones différentes : un tunnel de mine souterrain et un couloir intérieur étroit. Également, une architecture mobile combinant SDWN et NFV (Network Functions Virtualization) a été réalisée
Reconfigurable Antennas
In this new book, we present a collection of the advanced developments in reconfigurable antennas and metasurfaces. It begins with a review of reconfigurability technologies, and proceeds to the presentation of a series of reconfigurable antennas, UWB MIMO antennas and reconfigurable arrays. Then, reconfigurable metasurfaces are introduced and the latest advances are presented and discussed
Digital Filters
The new technology advances provide that a great number of system signals can be easily measured with a low cost. The main problem is that usually only a fraction of the signal is useful for different purposes, for example maintenance, DVD-recorders, computers, electric/electronic circuits, econometric, optimization, etc. Digital filters are the most versatile, practical and effective methods for extracting the information necessary from the signal. They can be dynamic, so they can be automatically or manually adjusted to the external and internal conditions. Presented in this book are the most advanced digital filters including different case studies and the most relevant literature
NASA Tech Briefs, June 2004
Topics covered include: COTS MEMS Flow-Measurement Probes; Measurement of an Evaporating Drop on a Reflective Substrate; Airplane Ice Detector Based on a Microwave Transmission Line; Microwave/Sonic Apparatus Measures Flow and Density in Pipe; Reducing Errors by Use of Redundancy in Gravity Measurements; Membrane-Based Water Evaporator for a Space Suit; Compact Microscope Imaging System with Intelligent Controls; Chirped-Superlattice, Blocked-Intersubband QWIP; Charge-Dissipative Electrical Cables; Deep-Sea Video Cameras Without Pressure Housings; RFID and Memory Devices Fabricated Integrally on Substrates; Analyzing Dynamics of Cooperating Spacecraft; Spacecraft Attitude Maneuver Planning Using Genetic Algorithms; Forensic Analysis of Compromised Computers; Document Concurrence System; Managing an Archive of Images; MPT Prediction of Aircraft-Engine Fan Noise; Improving Control of Two Motor Controllers; Electro-deionization Using Micro-separated Bipolar Membranes; Safer Electrolytes for Lithium-Ion Cells; Rotating Reverse-Osmosis for Water Purification; Making Precise Resonators for Mesoscale Vibratory Gyroscopes; Robotic End Effectors for Hard-Rock Climbing; Improved Nutation Damper for a Spin-Stabilized Spacecraft; Exhaust Nozzle for a Multitube Detonative Combustion Engine; Arc-Second Pointer for Balloon-Borne Astronomical Instrument; Compact, Automated Centrifugal Slide-Staining System; Two-Armed, Mobile, Sensate Research Robot; Compensating for Effects of Humidity on Electronic Noses; Brush/Fin Thermal Interfaces; Multispectral Scanner for Monitoring Plants; Coding for Communication Channels with Dead-Time Constraints; System for Better Spacing of Airplanes En Route; Algorithm for Training a Recurrent Multilayer Perceptron; Orbiter Interface Unit and Early Communication System; White-Light Nulling Interferometers for Detecting Planets; and Development of Methodology for Programming Autonomous Agents
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