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Articles 1561 - 1590 of 2088

Full-Text Articles in Systems and Communications

Footwear-Centric Body Area Network With Directional Uwb Antenna, Domenico Gaetano, Vit Sipal, Patrick Mcevoy, Max Ammann, C Brannigan, Louise Keating, Frances Horgan Jul 2013

Footwear-Centric Body Area Network With Directional Uwb Antenna, Domenico Gaetano, Vit Sipal, Patrick Mcevoy, Max Ammann, C Brannigan, Louise Keating, Frances Horgan

Articles

A footwear-centric body area network employing a directional antenna is compared with waist-centric systems using omnidirectional and directional antennas. The impact of body movements on path gain is analysed for two bands at 3.99 GHz and 7.99 GHz. The path gain and data rate results demonstrate that footwear-centric configurations are equivalent or better than waist-centric body area networks.


Adaptive Ofdm For Wireless Interconnect In Confined Enclosures, Vit Sipal, Javier Gelabert, Christopher J. Stevens, Ben Allen, David Edwards Jul 2013

Adaptive Ofdm For Wireless Interconnect In Confined Enclosures, Vit Sipal, Javier Gelabert, Christopher J. Stevens, Ben Allen, David Edwards

Articles

This letter considers and recommends OFDM with adaptive subcarrier modulation as a suitable candidate for wireless UWB communication in computer chassis. A rigorous measurement campaign studies the guaranteed spectral efficiency. It concludes that enhancement of the existing WiMedia OFDM systems with a bandwidth of 528 MHz in order to support adaptive OFDM would enable data-rates above 1 Gbps over short ranges, i.e. the spectral efficiency would be doubled. Moreover, the guaranteed spectral efficiency is shown to increase with bandwidth, i.e. the guaranteed data-rate increases better than linearly with bandwidth.


Open Source Kiswahili Spell Checker (Sw-Tz), Hashim Twaakyondo Jun 2013

Open Source Kiswahili Spell Checker (Sw-Tz), Hashim Twaakyondo

Tanzania Journal of Engineering and Technology (TJET)

Different English software products are localized into many native languages spoken around the world, the most popular software products localized so far are word processing software and web browsers. The effort has begun to localize these software products in Kiswahili language which is widely spoken in Tanzania, East and Central Africa. Kiswahili is an official language of Tanzania, and is a national language in Uganda and Kenya. To make these software products useful to Kiswahili speaking community particularly in Tanzania a new Kiswahili spell checker has been developed and, it uses most of the Kiswahili words spoken in Tanzania and …


2d Autocad Geometric Data Extraction And Post Processing For Numerical Control, Tito Mwinuka Jun 2013

2d Autocad Geometric Data Extraction And Post Processing For Numerical Control, Tito Mwinuka

Tanzania Journal of Engineering and Technology (TJET)

In this paper, a method of extracting 2D geometric data from AutoCAD drawing and post processing for Numerical Control (NC) is presented. Geometric data already available in the Drawing Interchange Files (DXF) can be utilized to accurately and economically prepare part programs for controlling NC/CNC machine tools. AutoCAD, being general purpose software, stores its geometric data in a form that cannot be directly applied for automatic generation of Numerical Control (NC) codes. The way around the discrepancy between the structure of a drawing database (DXF files) and the information requirement for part programming is addressed in this work. NC programming …


Gas Leakage Detection System (Glds), Daudi Simbeye Jun 2013

Gas Leakage Detection System (Glds), Daudi Simbeye

Tanzania Journal of Engineering and Technology (TJET)

This paper mainly focuses on the detection of gas leakage and providing security when the user is around or away from home. The system is Short Message Service (SMS) based and uses wireless technology for providing security against gas leakage to users hence cost effective and more adaptable. The system comprises of sensors for detecting gas leak interfaced to microcontroller that will give an alert to user whenever there is a gas leakage, display warning information by using Liquid Crystal Display (LCD), sending SMS to the user for notification wherever he/she might be and turning off electric power with the …


Comparison Of Non-Coherent Linear Detection Algorithms Applied To A 2-D Numerical Breast Model, Giuseppe Ruvio, Raffaele Solimene, Antonio Cuccaro, Max Ammann Jun 2013

Comparison Of Non-Coherent Linear Detection Algorithms Applied To A 2-D Numerical Breast Model, Giuseppe Ruvio, Raffaele Solimene, Antonio Cuccaro, Max Ammann

Articles

A comparative analysis of an imaging method based on a multifrequency Multiple Signal Classification (MUSIC) approach against two common linear detection algorithms based on noncoherent migration is made. The different techniques are tested using synthetic data generated through CST Microwave Studio and a phantom developed from MRI scans of a mostly fat breast. The multifrequency MUSIC approach shows an overall superior performance compared to the noncoherent techniques. This letter reports that this highly performing algorithm does not require any antenna calibration or phase response estimation and allows the use of efficient and complex antenna geometries without difficult algorithm redefinitions.


The Design And Analysis Of Electrically Large Custom-Shaped Reflector Antennas, Joshua M. Wilson Jun 2013

The Design And Analysis Of Electrically Large Custom-Shaped Reflector Antennas, Joshua M. Wilson

Theses and Dissertations

Designing and analyzing electrically large reflectors poses numerically complex problems because the reflector must be sampled finely to obtain an accurate solution, causing an unwieldy number of samples. In addition to these complexities, a custom-shaped reflector poses a new analysis problem. Previously developed methods and theorems including Geometric Optics, Ray-Tracing, Surface Equivalence Theorems, Image Theory, and Physical Optics can be applied to these custom-shaped reflectors however. These methods all share in common their capability to provide accurate results in the analysis of electrically large structures. In this thesis, two custom-shaped reflector concepts are explored which include a rectangular shaped, spherically …


Pier Portal Project Ii, Andy Lam, Brian Markwart Jun 2013

Pier Portal Project Ii, Andy Lam, Brian Markwart

Computer Engineering

The goal of this project is to design and build a remotely controllable camera system that will be deployed at the Cal Poly Pier located in Avila Beach. The system is composed of a camera and all of its lighting and movement controlling hardware enclosed into a waterproof acrylic tube, allowing it to be lowered underwater. The camera will stream its video feed onto a website where any user will be able to watch a live video stream from the pod. In addition, users with the correct privileges will be able to remotely control of the camera system via the …


Eco Sensor Pod, Austin Zuffi, Michael Chamoures Jun 2013

Eco Sensor Pod, Austin Zuffi, Michael Chamoures

Computer Engineering

The EcoSensor Pod, designed by the UCSD Data Turbine group, is a self-contained hardware/software solution for environmental monitoring, disaster response, and other real-time sensing applications. We improved upon the design of the Sensor Pod by 1. Developing a custom PCB for the system to remove the problem of wires becoming de-attached in harsh environment deployments and 2. Creating an easy-to-use web application that provides the UCSD team with the ability to view various charts displaying both past and live, real-time data. These modifications were successfully implemented and tested and will make future deployments of the EcoSensor Pod more robust and …


Design Of An Energy Efficient Virtual End Node Client Using Openadr2.0a And Smap, Kevin Navero Jun 2013

Design Of An Energy Efficient Virtual End Node Client Using Openadr2.0a And Smap, Kevin Navero

BioResource and Agricultural Engineering

Demand Response (DR) describes the set of actions taken to impose a reduction in electrical loads to stabilize the power grid and decrease costs. It is used when power grid emergencies or extremely high demand and congestion, threaten the electricity supply-demand balance. Automated Demand Response (ADR) describes a web-based control system that triggers DR events automatically by signaling other pre-programmed control systems. This project intends to use the OpenADR2.0 specifications provided by the OpenADR Alliance to construct an open source Virtual End Node (VEN) client to retrieve DR signals. The Simple Measurement and Actuation Profile (sMAP) software is also used …


Practical Irrigation Scheduling Program, Dominic Sween Jun 2013

Practical Irrigation Scheduling Program, Dominic Sween

BioResource and Agricultural Engineering

This senior project discusses the design, construction, and evaluation of an irrigation scheduling program that aids users in alfalfa irrigation management, with the potential for application with other crops. The program uses a very accurate irrigation prediction model that forecasts what the estimated irrigation need of each week will be, as well as the number of irrigations needed to satisfy the requirement. The model was found to predict the sum of the actual required weekly irrigation amount within less than 1% of the true value. The program was based off the single crop coefficient approach that was outlined previously by …


Path Loss In An Urban Peer-To-Peer Channel For Six Public-Safety Frequency Bands, David W. Matolak, Qian Zhang, Qiong Wu Jun 2013

Path Loss In An Urban Peer-To-Peer Channel For Six Public-Safety Frequency Bands, David W. Matolak, Qian Zhang, Qiong Wu

Faculty Publications

We provide path loss data and models for a peer-to-peer wireless channel for an urban environment in six public safety bands, for simultaneous transmission to five spatially separated receiving sites. Results are from measurements in Denver, Colorado. The six frequencies at which we measured are (in MHz) 430, 750, 905, 1834, 2400, and 4860. Both line-of-sight and non-line-of-sight conditions were covered, and we quantify path loss exponents and linear-fit standard deviations as functions of frequency and location. Line-of-sight results agree with prior work, but non-line-of-sight exponents, from 3.6-7.3, are generally larger than in most other references.


Buddy: A Breathalyzer For Iphone, Douglas Blaalid, Brandon Bevans Jun 2013

Buddy: A Breathalyzer For Iphone, Douglas Blaalid, Brandon Bevans

Electrical Engineering

Buddy is a Breathalyzer for the iPhone designed to be more a product than a project. Through proprietary hardware and a custom iOS application, Buddy provides users with a previously untapped link from the alcohol in their body to the display on their phones. Buddy uses an alcohol sensor connected to an Arduino Uno to accurately detect the BAC of the user’s breath. The BAC is then transmitted to an iPhone via the headphone jack where it is displayed and logged in a captivating app. The finished prototype successfully measured the approximate BAC of intoxicated users. The product website has …


High Frequency Open Air Optical Communication System, Alexander C. Wolff Jun 2013

High Frequency Open Air Optical Communication System, Alexander C. Wolff

Electrical Engineering

The goal of this project is to create a wireless optical communication system that operates at high frequencies (up to 3 GHz). The system will function by taking a digital electric input signal, converting it to a photonic signal, recovering the signal at the other end of a short distance (~1 foot) and converting it back into a digital signal. Unlike the more common fiber-optic data transmission systems, this system will transmit light through air, instead of fiber, as its medium. Doing so will have the benefits of a wireless system combined with the benefits from an optical system, including …


A Novel Unit Cell Antenna For Highly Integrated Phased Arrays In The Shf Band, Timothy Bryan Ogilvie Jun 2013

A Novel Unit Cell Antenna For Highly Integrated Phased Arrays In The Shf Band, Timothy Bryan Ogilvie

Master's Theses

Phased arrays are electromagnetic antenna systems comprised of many radiating elements and processing electronics. Radiating elements are typically positioned in an orderly grid within the antenna aperture. In the receive mode of operation, radiating elements capture some of the signal energy from incoming radiation and guide these signals to processing electronics. Signals are filtered and amplified to maintain the desired sensitivity and complexly weighted using circuits with reconfigurable amplification gain and phase delay. Finally, all signals are combined. The summation of these complexly weighted spatial samples forms a spatial filter in the same way complexly weighted temporal samples establish a …


Nonlinearity Analysis And Predistortion Of 4g Wireless Communication Systems, Xiao Li May 2013

Nonlinearity Analysis And Predistortion Of 4g Wireless Communication Systems, Xiao Li

Dissertations and Theses

The nonlinearity of RF power amplifiers (PA) is one of critical concerns for RF designers because it causes spectral regrowth related to in-band and out-of-band spurious emissions control in communication standards. Traditionally, RF power amplifiers must be backed off considerably from the peak of their power level in order to prevent spectral regrowth. The digital predistortion (DPD) technique is being widely used for compensation of the nonlinearity of RF power amplifiers, as the high power efficiency becomes increasely important in wireless communication systems.

However, the latest generations of communication systems, such as Wi-Fi, WiMAX, and LTE, using wider bandwidth have …


Reliability Analysis Of Social Networks, Kellie R. Schneider May 2013

Reliability Analysis Of Social Networks, Kellie R. Schneider

Graduate Theses and Dissertations

The primary focus of this dissertation is on the quantification of actor interaction and the dissemination of information through Social networks. Social networks have long been used to model the interactions between people in various Social and professional contexts. These networks allow for the explicit modeling of the complex interrelations between relevant individuals within an organization and the role they play in the decision making process. This dissertation considers Social networks represented as network flow models in which actors have the ability to provide some level of influence over other actors within the network. The models developed incorporate performance metrics …


A Compact Shorted Printed Monopole Antenna For Tv White Space Trials, Matthias John, Max Ammann Apr 2013

A Compact Shorted Printed Monopole Antenna For Tv White Space Trials, Matthias John, Max Ammann

Conference Papers

This paper presents a compact shorted printed monopole antenna for machine-to-machine, remote sensing and rural wireless applications in the TV whitespace band from 470 MHz to 862 MHz. The antennas performance in this operating band is demonstrated.


Analysis Of The Feasibility Of Utilizing Wakeup Radios To Optimize Energy And Latency Performance Of Wireless Sensor Networks, Benjamin D. Parks Apr 2013

Analysis Of The Feasibility Of Utilizing Wakeup Radios To Optimize Energy And Latency Performance Of Wireless Sensor Networks, Benjamin D. Parks

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

Wireless sensor networks (WSNs) have the potential to radically improve our lives by pervasive environmental monitoring in many applications. However, there are many applications that would be ideal for WSNs, but where reportable events occur with long (days, weeks) or unpredictable durations between occurrences. These uses are hampered by the high energy and latency costs of always-on and periodic wakeup networks, which waste energy on node synchronization and idle monitoring of the RF channel, and exhibit unacceptably high latency for urgent events, e.g., alarms. This thesis proposes, designs, assembles and tests, in a multi-hop WSN test bed, a wakeup receiver …


Impact Of Primary User Activity On The Performance Of Energy-Based Spectrum Sensing In Cognitive Radio Systems, Sara L. Macdonald Apr 2013

Impact Of Primary User Activity On The Performance Of Energy-Based Spectrum Sensing In Cognitive Radio Systems, Sara L. Macdonald

Electrical & Computer Engineering Theses & Dissertations

Increasing numbers of wireless devices and mobile data requirements have led to a spectrum shortage. However spectrum utilization percentages are often low due to the current static spectrum allocation process where primary users (PUs) are given exclusive use to spectrum. Several mechanisms to increase spectrum utilization have been proposed including opportunistic spectrum access (OSA). Cognitive Radio (CR) is an emerging concept in wireless communication systems that aims to enable OSA in licensed frequencies by secondary users (SUs). CR systems are expected to sense the spectrum in order to determine if the PU is transmitting. Therefore OSA performance relies on the …


Communication Technology In The Military, Jordan Diehl Apr 2013

Communication Technology In The Military, Jordan Diehl

Senior Seminars

No abstract provided.


Detecting Point-Like Sources Of Unknown Frequency Spectra, Raffaele Solimene, Giuseppe Ruvio, Angela Dell’Aversano, Antonio Cuccaro, Max Ammann, Rocco Pierri Apr 2013

Detecting Point-Like Sources Of Unknown Frequency Spectra, Raffaele Solimene, Giuseppe Ruvio, Angela Dell’Aversano, Antonio Cuccaro, Max Ammann, Rocco Pierri

Articles

The problem of detecting point-like sources whose frequency spectrum is unknown is addressed. Limitations of single-frequency approaches are identified by analytical as well as numerical arguments. To overcome these limits, different multifrequency approaches which combine frequency data incoherently are compared. In particular, a novel multifrequency MUSIC-like algorithm based on interferometric concepts is proposed. Results show that the algorithm outperforms other methods under comparison.


Time Synchronization For Ofdm Transmission With Applications To 4g Wimax Wireless Systems, Hamad Alhajri Apr 2013

Time Synchronization For Ofdm Transmission With Applications To 4g Wimax Wireless Systems, Hamad Alhajri

Electrical & Computer Engineering Theses & Dissertations

Orthogonal Frequency Division Multiplexing (OFDM) has recently gained a lot of attention as a promising new technology for Broadband Wireless Access. OFDM-based communication systems decompose a high rate data stream into a set of lower data rate streams that are transmitted simultaneously over multiple subcarriers. WiMAX is an efficient and reliable wireless transmission standard that employs OFDM transmission. Due to its flexibility and mobility, WiMAX is becoming a preferred air interface for next generation broadband wireless systems. OFDM systems, including WiMAX, are very sensitive to time offsets introduced by radio signal propagation between transmitters and receivers. The lack of time …


Stochastic Modeling And Time-To-Event Analysis Of Voip Traffic, Imad Al Ajarmeh Mar 2013

Stochastic Modeling And Time-To-Event Analysis Of Voip Traffic, Imad Al Ajarmeh

College of Computing and Digital Media Dissertations

Voice over IP (VoIP) systems are gaining increased popularity due to the cost effectiveness, ease of management, and enhanced features and capabilities. Both enterprises and carriers are deploying VoIP systems to replace their TDM-based legacy voice networks. However, the lack of engineering models for VoIP systems has been realized by many researchers, especially for large-scale networks. The purpose of traffic engineering is to minimize call blocking probability and maximize resource utilization. The current traffic engineering models are inherited from the legacy PSTN world, and these models fall short from capturing the characteristics of new traffic patterns. The objective of this …


Automatic Modulation Classification Of Common Communication And Pulse Compression Radar Waveforms Using Cyclic Features, John A . Hadjis Mar 2013

Automatic Modulation Classification Of Common Communication And Pulse Compression Radar Waveforms Using Cyclic Features, John A . Hadjis

Theses and Dissertations

This research develops a feature-based MAP classification system and applies it to classify several common pulse compression radar and communication modulations. All signal parameters are treated as unknown to the classifier system except SNR and the signal carrier frequency. The features are derived from estimated duty cycle, cyclic spectral correlation, and cyclic cumulants. The modulations considered in this research are BPSK, QPSK, 16-QAM, 64-QAM, 8-PSK, and 16-PSK communication modulations, as well as Barker coded, Barker coded, Barker coded, Frank coded, Px49 coded, and LFM pulse compression modulations. Simulations show that average correct signal modulation type classification %C 90% is achieved …


Spectrum Regrowth For Ofdm-Based Lte And Wimax Systems, Bosi Chen Jan 2013

Spectrum Regrowth For Ofdm-Based Lte And Wimax Systems, Bosi Chen

Dissertations and Theses

An abstract of the thesis of Bosi Chen for the Master of Science in Electrical and Computer Engineering presented Aug 1st, 2012. Title: Spectrum Regrowth for OFDM-based LTE and WiMAX Systems. In OFDM-based (Orthogonal Frequency Dimension Multiplexing) LTE (Long Term Evolution) and WiMAX (Worldwide Interoperability for Microwave Access) Systems, one of the critical components is the RF power amplifier. With current technologies, RF power amplifiers are not perfectly linear. The nonlinearity of an RF power amplifier is one of the main concerns in RF power amplifier design. The nonlinearity control is described by the out-of-band power emission levels, and the …


Comparison Of Post-Detonation Combustion In Explosives Incorporating Aluminum Nanoparticles: Influence Of The Passivation Layer, William K. Lewis, C. G. Rumchik, M. J. Smith, K. A. Shiral Fernando, Christopher A. Crouse, Jonathan E. Spowart, Elena A. Guliants, Christopher E. Bunker Jan 2013

Comparison Of Post-Detonation Combustion In Explosives Incorporating Aluminum Nanoparticles: Influence Of The Passivation Layer, William K. Lewis, C. G. Rumchik, M. J. Smith, K. A. Shiral Fernando, Christopher A. Crouse, Jonathan E. Spowart, Elena A. Guliants, Christopher E. Bunker

Electrical and Computer Engineering Faculty Publications

Aluminum nanoparticles and explosive formulations that incorporate them have been a subject of ongoing interest due to the potential of aluminum particles to dramatically increase energy content relative to conventional organic explosives. We have used time-resolved atomic and molecular emission spectroscopy to monitor the combustion of aluminum nanoparticles within the overall chemical dynamicsof post-detonation fireballs. We have studied the energy release dynamics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) charges incorporating three types of aluminum nanoparticles: commercial oxide-passivated nanoparticles, oleic acid-capped aluminum nanoparticles (AlOA), and nanoparticles in which the oxide shell of the particle has been functionalized with an acrylic monomer and copolymerized into …


Maintaining The Master International Frequency Register, Frans G. Von Der Dunk Jan 2013

Maintaining The Master International Frequency Register, Frans G. Von Der Dunk

Space, Cyber, and Telecommunications Law Program: Faculty Publications

The present paper is the written elaboration of a presentation held under the same title at the workshop “International Regulations of Space Communications” held in Luxembourg on 24 and 25 May 2012. Consequently, the topic of this paper, the maintenance of the Master International Frequency Register as a key tool for allowing satellite communications to be a viable international sector of space activities, is viewed through the looking glass of the session title, “WRC-12 from the Perspective of International Telecommunications Law.”

In other words, it does not purport to deal with the actual details of maintaining the Register …


A New Variable Step-Size Zero-Point Attracting Projection Algorithm, Jianming Liu, Steven L. Grant Jan 2013

A New Variable Step-Size Zero-Point Attracting Projection Algorithm, Jianming Liu, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a new variable step-size (VSS) scheme for the recently introduced zero-point attracting projection (ZAP) algorithm. The proposed variable step-size ZAPs are based on the gradient of the estimated filter coefficients' sparseness that is approximated by the difference between the sparseness measure of current filter coefficients and an averaged sparseness measure. Simulation results demonstrate that the proposed approach provides both faster convergence rate and better tracking ability than previous ones. © 2013 IEEE.


Independent Component Analysis Enhancements For Source Separation In Immersive Audio Environments, Yue Zhao Jan 2013

Independent Component Analysis Enhancements For Source Separation In Immersive Audio Environments, Yue Zhao

Theses and Dissertations--Electrical and Computer Engineering

In immersive audio environments with distributed microphones, Independent Component Analysis (ICA) can be applied to uncover signals from a mixture of other signals and noise, such as in a cocktail party recording. ICA algorithms have been developed for instantaneous source mixtures and convolutional source mixtures. While ICA for instantaneous mixtures works when no delays exist between the signals in each mixture, distributed microphone recordings typically result various delays of the signals over the recorded channels. The convolutive ICA algorithm should account for delays; however, it requires many parameters to be set and often has stability issues. This thesis introduces the …