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2,334 full-text articles. Page 96 of 102.

Underwater Localization And Tracking Of Physical Systems, Patrick E. Carroll 2011 University of Connecticut

Underwater Localization And Tracking Of Physical Systems, Patrick E. Carroll

Master's Theses

In this paper, we investigate the problem of localizing an underwater sensor node basedon message broadcasting from multiple surface nodes. With the time-of-arrival measurementsfrom a DSP-based multicarrier modem, each sensor node localizes itself based on the traveltime differences among multiple senders to the receiver. Using one-way message passing, such asolution can scale to accommodate a large number of nodes in a network. We consider the issuefrom not only the physical layer, but also at the node processing layer by incorporating a trackingsolution. We present simulation results as well as preliminary testing results in a swimming poolwith both stationary and moving …


Wireless Communications And Cognitive Radio Transmissions Under Quality Of Service Constraints And Channel Uncertainty, Sami Akin 2011 University of Nebraska-Lincoln

Wireless Communications And Cognitive Radio Transmissions Under Quality Of Service Constraints And Channel Uncertainty, Sami Akin

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

In this thesis, we study wireless communications and cognitive radio transmissions under quality of service (QoS) constraints and channel uncertainty. Initially, we focus on a time-varying Rayleigh fading channel and assume that no prior channel knowledge is available at the transmitter and the receiver. We investigate the performance of pilot-assisted wireless transmission strategies. In particular, we analyze different channel estimation techniques, including single-pilot minimum mean-square-error (MMSE) estimation, and causal and noncausal Wiener filters, and analyze efficient resource allocation strategies. Subsequently, we study the training-based transmission and reception schemes over a priori unknown, Rayleigh fading relay channels in which the fading …


On The Economic Viability Of Network Systems And Architectures, Soumya Sen 2011 University of Pennsylvania

On The Economic Viability Of Network Systems And Architectures, Soumya Sen

Publicly Accessible Penn Dissertations

Understanding the relationship between technology and economics is fundamental to making judicious policy and design decisions. Many technologies that are successful in meeting their technical goals often fail to get adopted due to economic factors. This holds true even for networked systems, e.g., the Internet, which witnessed failures in the adoption of QoS solutions, IPv6 migration etc., due to factors such as high costs, lack of demand, and weight of incumbency. To gain better insights into these issues, researchers need access to analytical frameworks that account for both technological and economic factors and provide useful design guidelines. This dissertation was …


Investigation Of Vertical Handoff Techniques In Integrated Wlan/Cellular Networks And Performance Analysis Of Horizon Handoff In Wimax Networks, Elaheh Arabmakki 2011 Morehead State University

Investigation Of Vertical Handoff Techniques In Integrated Wlan/Cellular Networks And Performance Analysis Of Horizon Handoff In Wimax Networks, Elaheh Arabmakki

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirement for the Degree of Master of Science by Elaheh Arabmakki May 9, 2011.


Exploration Of Spatial Diversity In Multi-Antenna Wireless Communication Systems, Shichuan Ma 2011 University of Nebraska-Lincoln

Exploration Of Spatial Diversity In Multi-Antenna Wireless Communication Systems, Shichuan Ma

Theses, Dissertations, & Student Research in Computer Electronics & Engineering

With increasing demand on wireless internet and personal multimedia, the data rate of wireless communications is expected to increase dramatically. Future wireless networks face challenges of supporting data rates higher than one gigabits per second. Among various technologies, multi-antennas, also known as multiple-input multiple-output (MIMO), are undoubtedly the most promising to enable higher data rates. By employing the extra degrees of freedom in the spatial domain, multi-antenna techniques enhance the wireless communication systems through array gain, spatial diversity, and spatial multiplexing. Although multi-antenna systems have been utilized for more than ten years, a thorough analysis of various aspects of multi-antenna …


Examination Of Chaotic Signal Encryption And Recovery For Secure Communication Using Hybrid Acousto-Optic Feedback, Monish Ranjan Chatterjee, Mohammed A. Al-Saedi 2011 University of Dayton

Examination Of Chaotic Signal Encryption And Recovery For Secure Communication Using Hybrid Acousto-Optic Feedback, Monish Ranjan Chatterjee, Mohammed A. Al-Saedi

Electrical and Computer Engineering Faculty Publications

Generation of chaos from acousto-optic (A-O)Bragg cell modulators with an electronic feedback has been studied for over 3 decades. Since an acousto-optic Bragg cell with zeroth- and first-order feedback exhibits chaotic behavior past the threshold for bistability, such a system was recently examined for possible chaotic encryption of simple messages (such as a low-amplitude sinusoidal signal) applied via the bias input of the sound cell driver. Subsequent recovery of the message signal was carried out via a heterodyne-type strategy employing a locally generated chaotic carrier, with threshold parameters matched to the transmitting Bragg cell.

In this paper, we present numerical …


Low Power Rtty And Psk31 Decoder For Ham Radio Applications, Benjamin Bales 2011 University of Tennessee - Knoxville

Low Power Rtty And Psk31 Decoder For Ham Radio Applications, Benjamin Bales

Chancellor’s Honors Program Projects

No abstract provided.


An Exploration Of Knowledge And Skills Transfer From A Formal Software Engineering Curriculum To A Capstone Practicum Project, Ray Bareiss, Ed Katz 2011 Carnegie Mellon University

An Exploration Of Knowledge And Skills Transfer From A Formal Software Engineering Curriculum To A Capstone Practicum Project, Ray Bareiss, Ed Katz

Ray Bareiss

Students at Carnegie Mellon Silicon Valley complete a team-based practicum project for an industrial sponsor as the capstone of their master’s education in software engineering. Over time, the faculty member who typically serves as advisor for such projects has been disturbed by the failure of several student teams to transfer some relevant knowledge and skills from the formal curriculum to the relatively unstructured practicum project environment. We conducted a survey of all 2010 software engineering students to ascertain the most significant selfreported shortcomings. This paper presents the survey data and then discusses the results in terms of a theory of …


A Simple Distributed Method For Control Over Wireless Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam 2011 University of Pennsylvania

A Simple Distributed Method For Control Over Wireless Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

We present a distributed scheme used for control over wireless networks. In our previous work, we introduced the concept of a Wireless Control Network (WCN), where the network itself, with no centralized node, acts as the controller. In this work, we show how the WCN can be modified to include observer style updates which substantially improves robustness of the closed-loop system to link failures. In addition, we analyze how the WCN simplifies extraction of the communication and computation schedules and enables system compositionality and scalability.


Scalar Em Beam Propagation In Inhomogeneous Media, John M. Jarem, Partha P. Banerjee 2011 University of Alabama, Huntsville

Scalar Em Beam Propagation In Inhomogeneous Media, John M. Jarem, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

In the previous chapter, we reviewed some of the mathematical preliminaries that will be useful later on in the text. In this chapter, we discuss some of the basic concepts of scalar wave propagation, and discuss an important numerical method, called the beam propagation method (BPM), to study propagation in linear media and in media with induced nonlinearities. Furthermore, we also discuss propagation through induced gratings, both transmission and reflection type, in order to assess energy coupling between participating waves. Finally, we introduce readers to an important characterization method, called the z-scan method, which is often used to determine the …


Binary And Core-Shell Nanoparticle Dispersed Liquid Crystal Cells For Metamaterial Applications, George Nehmetallah, Rola Aylo, Partha P. Banerjee 2011 The Catholic University of America

Binary And Core-Shell Nanoparticle Dispersed Liquid Crystal Cells For Metamaterial Applications, George Nehmetallah, Rola Aylo, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We theoretically explored the feasibility of a tunable metamaterial using binary as well as core-shell nanoparticle dispersed liquid crystal cells in the infrared and optical regimes. Owing to the spatial variation of the permittivity of the liquid crystal host upon the application of a bias voltage, the host was decomposed into a layered medium and the effective refractive index recalculated for each layer due to the distribution of polaritonic and plasmonic nanoparticles.

The scattering, extinction, and absorption of such a nanoparticle dispersed liquid crystal cell were also found. Depending on the applied voltage bias across the liquid crystal host, the …


A Framework For Incident Detection And Notification In Vehicular Ad-Hoc Networks, Mahmoud Abuelela 2011 Old Dominion University

A Framework For Incident Detection And Notification In Vehicular Ad-Hoc Networks, Mahmoud Abuelela

Computer Science Theses & Dissertations

The US Department of Transportation (US-DOT) estimates that over half of all congestion events are caused by highway incidents rather than by rush-hour traffic in big cities. The US-DOT also notes that in a single year, congested highways due to traffic incidents cost over $75 billion in lost worker productivity and over 8.4 billion gallons of fuel. Further, the National Highway Traffic Safety Administration (NHTSA) indicates that congested roads are one of the leading causes of traffic accidents, and in 2005 an average of 119 persons died each day in motor vehicle accidents.

Recently, Vehicular Ad-hoc Networks (VANET) employing a …


Worse-Than-Rayleigh Fading: Experimental Results And Theoretical Models, David W. Matolak, Jeff Frolik 2011 University of South Carolina - Columbia

Worse-Than-Rayleigh Fading: Experimental Results And Theoretical Models, David W. Matolak, Jeff Frolik

Faculty Publications

This article is motivated by the recent recognition that channel fading for new wireless applications is not always well described by traditional models used for mobile communication systems. In particular, fading data collected for vehicleto- vehicle and wireless sensor network applications has motivated new models for conditions in which channel fading statistics can be worse than Rayleigh. We review the use of statistical channel models, describe our example applications, and provide both measured and modeling results for these severe fading conditions.


Imirok: Real-Time Imitative Robotic Arm Control For Home Robot Applications, Heng-Tze Cheng, Zheng Sun, Pei Zhang 2011 Carnegie Mellon University

Imirok: Real-Time Imitative Robotic Arm Control For Home Robot Applications, Heng-Tze Cheng, Zheng Sun, Pei Zhang

Zheng Sun

Training home robots to behave like human can help people with their daily chores and repetitive tasks. In this paper, we present Imirok, a system to remotely control robotic arms by user motion using low-cost, off-the-shelf mobile devices and webcam. The motion tracking algorithm detects user motion in real-time, without classifier training or predefined action set. Experimental results show that the system achieves 90% precision and recall rate on motion detection with blank background, and is robust under the change of cluttered background and user-to-camera distance.


Leveraging Mobile Context For Effective Collaboration And Task Management In Disaster Response, Faisal Luqman, Martin L. Griss 2011 Carnegie Mellon University

Leveraging Mobile Context For Effective Collaboration And Task Management In Disaster Response, Faisal Luqman, Martin L. Griss

Martin L Griss

Collaboration and task management is challenging in distributed, dynamically-formed teams, typical in large scale disaster response scenarios. Ineffective collaboration may result in poor performance and possible loss of life. In this paper, we present Overseer, an agent-based system that exploits context information from mobile devices to facilitate collaboration and task allocation. We describe our system architecture and show how mobile context can be used to create dynamic role-based assignments to support collaboration and effective task management.


Malicious And Malfunctioning Node Detection Via Observed Physical Layer Data, Tyler J. Hardy 2011 Air Force Institute of Technology

Malicious And Malfunctioning Node Detection Via Observed Physical Layer Data, Tyler J. Hardy

Theses and Dissertations

There are many mechanisms that can cause inadequate or unreliable information in sensor networks. A user of the network might be interested in detecting and classifying specific sensors nodes causing these problems. Several network layer based trust methods have been developed in previous research to assess these issues; in contrast this work develops a trust protocol based on observations of physical layer data collected by the sensors. Observations of physical layer data are used for decisions and calculations, and are based on just the measurements collected by the sensors. Although this information is packaged and distributed on the network layer, …


Routing Uavs To Co-Optimize Mission Effectiveness And Network Performance With Dynamic Programming, Spenser D. Lee 2011 Air Force Institute of Technology

Routing Uavs To Co-Optimize Mission Effectiveness And Network Performance With Dynamic Programming, Spenser D. Lee

Theses and Dissertations

In support of the Air Force Research Laboratory's (AFRL) vision of the layered sensing operations center, command and control intelligence surveillance and reconnaissance (C2ISR) more focus must be placed on architectures that support information systems, rather than just the information systems themselves. By extending the role of UAVs beyond simply intelligence, surveillance, and reconnaissance (ISR) operations and into a dual-role with networking operations we can better utilize our information assets. To achieve the goal of dual-role UAVs, a concrete approach to planning must be taken. This research defines a mathematical model and a non-trivial deterministic algorithmic approach to determining UAV …


Evaluating Information Assurance Control Effectiveness On An Air Force Supervisory Control And Data Acquisition (Scada) System, Jason R. Nielsen 2011 Air Force Institute of Technology

Evaluating Information Assurance Control Effectiveness On An Air Force Supervisory Control And Data Acquisition (Scada) System, Jason R. Nielsen

Theses and Dissertations

Supervisory Control and Data Acquisition (SCADA) systems are increasingly being connected to corporate networks which has dramatically expanded their attack surface to remote cyber attack. Adversaries are targeting these systems with increasing frequency and sophistication. This thesis seeks to answer the research question addressing which Information Assurance (IA) controls are most significant for network defenders and SCADA system managers/operators to focus on in order to increase the security of critical infrastructure systems against a Stuxnet-like cyber attack. This research applies the National Institute of Science and Technology (NIST) IA controls to an attack tree modeled on a remote Stuxnet-like cyber …


Touch2query Enabled Mobile Devices: A Case Study Using Openstreetmap And Iphone, Junjun Yin, James Carswell 2011 Technological University Dublin

Touch2query Enabled Mobile Devices: A Case Study Using Openstreetmap And Iphone, Junjun Yin, James Carswell

Conference papers

This paper describes our mobile spatial interaction (MSI) prototype Touch2Query which presents the idea of using the touch screen on mobile devices to assist in performing ad-hoc spatial queries. This approach differs from conventional mobile LBS applications where the query shape (search space) is limited to either a bounding box or radius. Instead, we provide functionality that allows users to interactively draw any desired query shape overlaid on an area of interest directly on a mobile device with their finger by combining vector primitives such as circles, polygons, polylines, and points. With the help of location and orientation aware mobile …


Single-Beam Holographic Tomography Creates Images In Three Dimensions, George Nehmetallah, Partha P. Banerjee, Nickolai Kukhtarev 2011 The Catholic University of America

Single-Beam Holographic Tomography Creates Images In Three Dimensions, George Nehmetallah, Partha P. Banerjee, Nickolai Kukhtarev

Electrical and Computer Engineering Faculty Publications

In digital holography (DH), the interference between light scattered from an object and a reference wave is recorded using a CCD camera. DH has various advantages over analog holography: no film processing is needed, reconstruction is performed using numerical methods, and no further experimental setup is necessary. However, one of the disadvantages of DH is that current CCDs have a resolution of approximately 1,000 lines/mm, which is less than that of photographic film.


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