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2,334 full-text articles. Page 95 of 102.

Exploring User-Provided Connectivity - A Simple Model, M. H. Afrasiabi, Roch A. Guérin 2011 University of Pennsylvania

Exploring User-Provided Connectivity - A Simple Model, M. H. Afrasiabi, Roch A. Guérin

Departmental Papers (ESE)

The advent of cheap and ubiquitous wireless access has introduced a number of new connectivity paradigms. This paper investigates one of them, user-provided connectivity or UPC. In contrast to traditional infrastructure-based connectivity, e.g., connectivity through the up-front build-out of expensive base-stations, UPC realizes connectivity organically as users join and expand its coverage. The low(er) deployment cost this affords is one of its main attractions. Conversely, the disadvantages of connectivity sharing and a high barrier-to-entry from low initial penetration create strong disincentives to its adoption. The paper’s contributions are in formulating and solving a simple model that captures key aspects of …


Wideband Dual-Frequency Dual-Polarized Dipole-Like Antenna, Xiulong Bao, Max Ammann 2011 Technological University Dublin

Wideband Dual-Frequency Dual-Polarized Dipole-Like Antenna, Xiulong Bao, Max Ammann

Articles

A wideband dual-frequency dual-polarized printed antenna is proposed for LTE, WLAN, and UWB systems. The dual-band antenna provides wide impedance bandwidths of 74% with respect to the center frequency of 2.725 GHz, and 39% with respect to the center frequency of 7.15 GHz. An open slot in the ground plane between the feed arms provides an orthogonal path to realize an embedded circularly polarized band at 2.35 GHz with an axial-ratio bandwidth of 16%. Dual-band characteristics are achieved by an asymmetrical dipole-like element and the coupling configuration between the T-shaped feed line and the wide ground-plane slot.


Chaotic Bandgaps In Hybrid Acousto-Optic Feedback And Their Implications, Monish Ranjan Chatterjee, Mohammed A. Al-Saedi 2011 University of Dayton

Chaotic Bandgaps In Hybrid Acousto-Optic Feedback And Their Implications, Monish Ranjan Chatterjee, Mohammed A. Al-Saedi

Electrical and Computer Engineering Faculty Publications

The nonlinear dynamics of a hybrid acousto-optic device was examined from the perspective of the Lyapunov exponent (LE) and bifurcation maps. The plots for LE versus system parameters and bifurcation maps have recently been examined against known simulation results including chaotic encryption experiments [1]. It is verified that the "loop gain" (feedback gain (β) times incident light amplitude (Iin) needs to be greater than one as a necessary , but not sufficient condition for the onset of chaos.

It is found that for certain combinations of β, Iin, net bias voltage (αtοt), and the initial value of the first-order scattered …


Monofilar Spiral Slot Antenna For Dual-Frequency Dual-Sense Circular Polarization, Xiulong Bao, Max Ammann 2011 Technological University Dublin

Monofilar Spiral Slot Antenna For Dual-Frequency Dual-Sense Circular Polarization, Xiulong Bao, Max Ammann

Articles

A dual-band antenna with right-hand circular polarization for the first frequency and the counter polarization at the second frequency is realized with compact printed spiral slots. The coupled spiral slots are fed by a 50 Ω microstrip line. Dual-sense circularly-polarized performance is achieved by realizing oppositely-directed current rotation for the two frequency bands. A parametric study shows that the additional slot significantly improves the bandwidth for both frequency bands. Measured results show that the fractional impedance bandwidth is greater than 18% for both bands. The 3 dB axial-ratio bandwidths are 4.5% and 3.5% for the RHCP and LHCP bands, respectively.


Cyclostationary Detection For Ofdm In Cognitive Radio Systems, Marcos E. Castro 2011 University of Nebraska-Lincoln

Cyclostationary Detection For Ofdm In Cognitive Radio Systems, Marcos E. Castro

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

Research on cognitive radio systems has attracted much interest in the last 10 years. Cognitive radio is born as a paradigm and since then the idea has seen contribution from technical disciplines under different conceptual layers. Since then improvements on processing capabilities have supported the current achievements and even made possible to move some of them from the research arena to markets.

Cognitive radio implies a revolution that is even asking for changes in current business models, changes at the infrastructure levels, changes in legislation and requiring state of the art technology.

Spectrum sensing is maybe the most important part …


Cyber Physical Complex Networks, Modeling, Analysis, And Control, Neveen Shlayan 2011 University of Nevada, Las Vegas

Cyber Physical Complex Networks, Modeling, Analysis, And Control, Neveen Shlayan

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research scrutinize various attributes of complex networks; mainly, modeling, sensing, estimation, safety analysis, and control. In this study, formal languages and finite automata are used for modeling incident management processes. Safety properties are checked in order to verify the system. This method introduces a systematic approach to incident management protocols that are governed by mostly unsystematic algorithms. A portion of the used data in this study is collected by means of radar and loop detectors. A weighted t-statistics methodology is developed in order to validate these detectors. The detector data is then used to extract travel time information where …


Wireless Passive Power Transfer Using Wire Antennas, Sheng Da Zhang 2011 California Polytechnic State University - San Luis Obispo

Wireless Passive Power Transfer Using Wire Antennas, Sheng Da Zhang

Electrical Engineering

This project tests and analyzes the efficiency of directional and omnidirectional antennas in wireless power transfer for charging. The project demonstrates the steps of construction and properties of dipole, monopole, and Yagi Uda antennas. A low power high frequency DC rectifier circuit converts the received RF power from the antenna and stored it as DC voltage on a capacitor. The receiver circuit also estimates the power received by the antenna. Wireless RF power transmission proves to be inefficient for short distances. The best efficiencies of the antennas were under 50% even at 0.1meter. The near field attenuation starts at around …


Primary User Emulation Attacks In Cognitive Radio - An Experimental Demonstration And Analysis, Benjamin James Ealey 2011 University of Tennessee - Knoxville

Primary User Emulation Attacks In Cognitive Radio - An Experimental Demonstration And Analysis, Benjamin James Ealey

Masters Theses

Cognitive radio networks rely on the ability to avoid primary users, owners of the frequency, and prevent collisions for effective communication to take place. Additional malicious secondary users, jammers, may use a primary user emulation attacks to take advantage of the secondary user's ability to avoid primary users and cause excessive and unexpected disruptions to communications. Two jamming/anti-jamming methods are investigated on Ettus Labs USRP 2 radios. First, pseudo-random channel hopping schemes are implemented for jammers to seek-and-disrupt secondary users while secondary users apply similar schemes to avoid all primary user signatures. In the second method the jammer uses adversarial …


Calibration Of Complex System Dynamics Models: A Practioner's Report, Rod Walker, Wayne W. Wakeland 2011 Altus Consulting, Inc.

Calibration Of Complex System Dynamics Models: A Practioner's Report, Rod Walker, Wayne W. Wakeland

Wayne W. Wakeland

This paper is not a typical academic paper that is solidly grounded in the literature. Instead, this paper reports practitioner’s experiences in rebuilding and calibrating a very large system dynamics model. A prior version of this model had been in use for over 10 years in an ongoing executive training simulation. That model had never worked correctly in several key areas, requiring the outputs to be manually adjusted by very experienced facilitators during the course of the simulation. The present project rebuilt the system dynamics model, redesigned the parts that weren’t working, and calibrated the resulting model to match the …


Calibration Of Complex System Dynamics Models: A Practioner's Report, Rod Walker, Wayne Wakeland 2011 Altus Consulting, Inc.

Calibration Of Complex System Dynamics Models: A Practioner's Report, Rod Walker, Wayne Wakeland

Systems Science Faculty Publications and Presentations

This paper is not a typical academic paper that is solidly grounded in the literature. Instead, this paper reports practitioner’s experiences in rebuilding and calibrating a very large system dynamics model. A prior version of this model had been in use for over 10 years in an ongoing executive training simulation. That model had never worked correctly in several key areas, requiring the outputs to be manually adjusted by very experienced facilitators during the course of the simulation. The present project rebuilt the system dynamics model, redesigned the parts that weren’t working, and calibrated the resulting model to match the …


Lna Lowers Noise, Raises Oip3 At 3.5 Ghz, Chin-Leong Lim 2011 Avago Technologies, Malaysia

Lna Lowers Noise, Raises Oip3 At 3.5 Ghz, Chin-Leong Lim

Chin-Leong Lim

A 3.5 GHz LNA with good noise figure, gain and linearity performances has been designed around a low-cost, QFN2x2-packaged monolithic integrated circuit (MMIC). Incorporation of bias regulator, ESD protection and stability network at chip-level reduces the external component count to 12. The proprietary 0.25 um EPHEMT process achieves +15-dB gain in single stage and less than 1 dB noise figure at 3.5 GHz.


Printed Circularly-Polarized Antenna With Ultra-Wide Axial-Ratio Bandwidth, Xiulong Bao, Max Ammann 2011 Technological University Dublin

Printed Circularly-Polarized Antenna With Ultra-Wide Axial-Ratio Bandwidth, Xiulong Bao, Max Ammann

Articles

A circularly polarised printed dipole-like antenna employing asymmetrical arms and an orthogonal slit in the ground plane is presented. It is fed by a stepped microstrip line which connects to the shorter arm. By utilising surface currents on the asymmetrical arms and the orthogonal feedline structure, circular polarisation is realised. Experimental and numerical data are in agreement and the measured results show a fractional impedance bandwidth of 41.3% (1.77–2.69 GHz) and a wide axial-ratio bandwidth of 38.4% (1.81–2.67 GHz).


San Luis Obispo Transit Tracker System Back-End Server, Daryl Alan A. Dimalanta 2011 California Polytechnic State University - San Luis Obispo

San Luis Obispo Transit Tracker System Back-End Server, Daryl Alan A. Dimalanta

Computer Engineering

This document gives the rationale, design process, technical implementation, testing procedures, and testing results of a back-end server used for the San Luis Obispo (SLO) Transit Tracker System. The SLO Transit Tracker System (SLOTTS) includes client software installed on mobile devices and a back-end server. The purpose of this system is to encourage SLO residents to utilize the transit system by having the client software present current bus location, navigation instructions, and bus schedule in a simple, fast, and easy to use mobile application.

Due to the limited central processing unit (CPU) and limited power supplied by the battery, route …


An Investigation Into Ultrasonic Communication For Near-Body Networks, Eric Joshua Escudero Jr., Gursewak Singh Rai 2011 California Polytechnic State University - San Luis Obispo

An Investigation Into Ultrasonic Communication For Near-Body Networks, Eric Joshua Escudero Jr., Gursewak Singh Rai

Electrical Engineering

The following report presents a study of body-area, free-space ultrasonic communication system. Two analog communication systems are investigated. The initial communications system setup relies upon the amplitude modulation (AM) techniques to transmit the signal. Such a system is prone to noise since the amplitude of the signal is directly affected by distance and the signal strength will deteriorate. The secondary communication system involves utilizing frequency modulation (FM). This method avoids the issue of losing information due to amplitude deterioration, but encounters delay issues. The main hardware components used in the approach outlined include ultrasonic transducers (UTs) used for both transmitting …


Wirelessly Operated Pa Loudspeaker System For Rmax Search-And-Rescue Uav: A Preliminary Design, Travis Luke, Nolan Uchizono 2011 California Polytechnic State University - San Luis Obispo

Wirelessly Operated Pa Loudspeaker System For Rmax Search-And-Rescue Uav: A Preliminary Design, Travis Luke, Nolan Uchizono

Electrical Engineering

This paper discusses the approach used to implement a wireless PA loudspeaker system on a search-and-rescue RMAX UAV.

The purpose of this project is to allow the continuation of communication between search-and-rescue workers as well as potential rescuees in an environment that won't always allow it. Since rugged terrain tends to cause interference between two radio communications, there needs to be a way to bypass this problem. In addition, people in need of rescue are unlikely to be using a radio on an emergency frequency, so there needs to be a way to efficiently issue orders or evacuation notices without …


Digital Modulations Using The Universal Software Radio Peripheral, Daniel Keith Artis 2011 California Polytechnic State University - San Luis Obispo

Digital Modulations Using The Universal Software Radio Peripheral, Daniel Keith Artis

Electrical Engineering

Software defined radios (SDRs) are versatile systems that integrate hardware and software to create a reprogrammable wireless system. Due to the versatility and hardware requirements of a SDR, they are typically expensive and not always affordable for educational institutions. GNU Radio is a free software package that allows users to do signal processing on any computer using python and C++. Using the Universal Software Radio Peripheral (USRP) board in conjunction with a standard personal computer (PC), a RF daughterboard, and the GNU Radio software, we can create a software defined radio that can transmit, receive, and process signals. Because the …


Laser Cursor, Michael Liman 2011 California Polytechnic State University - San Luis Obispo

Laser Cursor, Michael Liman

Electrical Engineering

A user controls a cursor on a computer screen using a laser pointer. A camera picks up the laser pointer’s position and sends the data to the computer to move the cursor in the correct position.


Discrete Alarm Clock, Travis Moore, Collin Barth 2011 California Polytechnic State University - San Luis Obispo

Discrete Alarm Clock, Travis Moore, Collin Barth

Electrical Engineering

The standard alarm clock, as used daily by millions worldwide, has clear room for modification and improvement. This paper documents an implementation that rectifies many of these flaws. Improvements include adjustable snooze length, an IR remote for ease of use, and an RF headset for discrete alarm use or potential incorporation into a device much like a hearing aid. The processes involved in creating a digital alarm clock, as well as the obstacles met in the implementation of the enhanced design, are detailed within.


Wireless Sensor Network For Energy And Environmental Monitoring: Helping Old Buildings Go Green, Jacob Power 2011 California Polytechnic State University - San Luis Obispo

Wireless Sensor Network For Energy And Environmental Monitoring: Helping Old Buildings Go Green, Jacob Power

Electrical Engineering

Today, the rising cost of energy and social trend of “going green” has put increasing pressure on commercial property owners to improve the efficiency of their investments. There is good reason for this, too. In the State of California, office buildings represent the single largest user of energy in the commercial sector. This project consisted of the design, implementation, construction, testing, and deployment of a wireless sensor network for energy and environmental monitoring in retrofit commercial office installations. The analyzed data generated by this system can be used by building management and owners to identify areas of inefficiency within the …


A Neural Network Receiver For Em-Mwd Communication, Timothy P. Whitacre 2011 California Polytechnic State University, San Luis Obispo

A Neural Network Receiver For Em-Mwd Communication, Timothy P. Whitacre

Master's Theses

Baseband digital communication in electro-magnetic measurement while drilling (EM-MWD) systems is often corrupted by non-white surface noise. The inability to reliably decode the transmitted signals in a noisy environment limits the depth at which EM-MWD systems can operate. Correlation receivers, which are optimal in the presence of additive white Gaussian noise, can be sub-optimal in the presence of various types of field noise at different drilling sites.

This thesis investigates the application of artificial neural networks (ANN) as communication receivers in EM-MWD baseband digital communication systems. The performances of various ANN architectures and training algorithms are studied and compared with …


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