Defense Notices
All students and faculty are welcome to attend the final defense of EECS graduate students completing their M.S. or Ph.D. degrees. Defense notices for M.S./Ph.D. presentations for this year and several previous years are listed below in reverse chronological order.
Students who are nearing the completion of their M.S./Ph.D. research should schedule their final defenses through the EECS graduate office at least THREE WEEKS PRIOR to their presentation date so that there is time to complete the degree requirements check, and post the presentation announcement online.
Upcoming Defense Notices
Elizabeth Wyss
A New Frontier for Software Security: Diving Deep into npmWhen & Where:
Eaton Hall, Room 2001B
Committee Members:
Drew Davidson, ChairAlex Bardas
Fengjun Li
Bo Luo
J. Walker
Abstract
Open-source package managers (e.g., npm for Node.js) have become an established component of modern software development. Rather than creating applications from scratch, developers may employ modular software dependencies and frameworks--called packages--to serve as building blocks for writing larger applications. Package managers make this process easy. With a simple command line directive, developers are able to quickly fetch and install packages across vast open-source repositories. npm--the largest of such repositories--alone hosts millions of unique packages and serves billions of package downloads each week.
However, the widespread code sharing resulting from open-source package managers also presents novel security implications. Vulnerable or malicious code hiding deep within package dependency trees can be leveraged downstream to attack both software developers and the end-users of their applications. This downstream flow of software dependencies--dubbed the software supply chain--is critical to secure.
This research provides a deep dive into the npm-centric software supply chain, exploring distinctive phenomena that impact its overall security and usability. Such factors include (i) hidden code clones--which may stealthily propagate known vulnerabilities, (ii) install-time attacks enabled by unmediated installation scripts, (iii) hard-coded URLs residing in package code, (iv) the impacts of open-source development practices, (v) package compromise via malicious updates, (vi) spammers disseminating phishing links within package metadata, and (vii) abuse of cryptocurrency protocols designed to reward the creators of high-impact packages. For each facet, tooling is presented to identify and/or mitigate potential security impacts. Ultimately, it is our hope that this research fosters greater awareness, deeper understanding, and further efforts to forge a new frontier for the security of modern software supply chains.
Alfred Fontes
Optimization and Trade-Space Analysis of Pulsed Radar-Communication Waveforms using Constant Envelope ModulationsWhen & Where:
Nichols Hall, Room 246 (Executive Conference Room)
Committee Members:
Patrick McCormick, ChairShannon Blunt
Jonathan Owen
Abstract
Dual function radar communications (DFRC) is a method of co-designing a single radio frequency system to perform simultaneous radar and communications service. DFRC is ultimately a compromise between radar sensing performance and communications data throughput due to the conflicting requirements between the sensing and information-bearing signals.
A novel waveform-based DFRC approach is phase attached radar communications (PARC), where a communications signal is embedded onto a radar pulse via the phase modulation between the two signals. The PARC framework is used here in a new waveform design technique that designs the radar component of a PARC signal to match the PARC DFRC waveform expected power spectral density (PSD) to a desired spectral template. This provides better control over the PARC signal spectrum, which mitigates the issue of PARC radar performance degradation from spectral growth due to the communications signal.
The characteristics of optimized PARC waveforms are then analyzed to establish a trade-space between radar and communications performance within a PARC DFRC scenario. This is done by sampling the DFRC trade-space continuum with waveforms that contain a varying degree of communications bandwidth, from a pure radar waveform (no embedded communications) to a pure communications waveform (no radar component). Radar performance, which is degraded by range sidelobe modulation (RSM) from the communications signal randomness, is measured from the PARC signal variance across pulses; data throughput is established as the communications performance metric. Comparing the values of these two measures as a function of communications symbol rate explores the trade-offs in performance between radar and communications with optimized PARC waveforms.
Arin Dutta
Performance Analysis of Distributed Raman Amplification with Different Pumping ConfigurationsWhen & Where:
Nichols Hall, Room 246 (Executive Conference Room)
Committee Members:
Rongqing Hui, ChairMorteza Hashemi
Rachel Jarvis
Alessandro Salandrino
Hui Zhao
Abstract
As internet services like high-definition videos, cloud computing, and artificial intelligence keep growing, optical networks need to keep up with the demand for more capacity. Optical amplifiers play a crucial role in offsetting fiber loss and enabling long-distance wavelength division multiplexing (WDM) transmission in high-capacity systems. Various methods have been proposed to enhance the capacity and reach of fiber communication systems, including advanced modulation formats, dense wavelength division multiplexing (DWDM) over ultra-wide bands, space-division multiplexing, and high-performance digital signal processing (DSP) technologies. To maintain higher data rates along with maximizing the spectral efficiency of multi-level modulated signals, a higher Optical Signal-to-Noise Ratio (OSNR) is necessary. Despite advancements in coherent optical communication systems, the spectral efficiency of multi-level modulated signals is ultimately constrained by fiber nonlinearity. Raman amplification is an attractive solution for wide-band amplification with low noise figures in multi-band systems.
Distributed Raman Amplification (DRA) have been deployed in recent high-capacity transmission experiments to achieve a relatively flat signal power distribution along the optical path and offers the unique advantage of using conventional low-loss silica fibers as the gain medium, effectively transforming passive optical fibers into active or amplifying waveguides. Also, DRA provides gain at any wavelength by selecting the appropriate pump wavelength, enabling operation in signal bands outside the Erbium doped fiber amplifier (EDFA) bands. Forward (FW) Raman pumping configuration in DRA can be adopted to further improve the DRA performance as it is more efficient in OSNR improvement because the optical noise is generated near the beginning of the fiber span and attenuated along the fiber. Dual-order FW pumping scheme helps to reduce the non-linear effect of the optical signal and improves OSNR by more uniformly distributing the Raman gain along the transmission span.
The major concern with Forward Distributed Raman Amplification (FW DRA) is the fluctuation in pump power, known as relative intensity noise (RIN), which transfers from the pump laser to both the intensity and phase of the transmitted optical signal as they propagate in the same direction. Additionally, another concern of FW DRA is the rise in signal optical power near the start of the fiber span, leading to an increase in the non-linear phase shift of the signal. These factors, including RIN transfer-induced noise and non-linear noise, contribute to the degradation of system performance in FW DRA systems at the receiver.
As the performance of DRA with backward pumping is well understood with relatively low impact of RIN transfer, our research is focused on the FW pumping configuration, and is intended to provide a comprehensive analysis on the system performance impact of dual order FW Raman pumping, including signal intensity and phase noise induced by the RINs of both 1st and the 2nd order pump lasers, as well as the impacts of linear and nonlinear noise. The efficiencies of pump RIN to signal intensity and phase noise transfer are theoretically analyzed and experimentally verified by applying a shallow intensity modulation to the pump laser to mimic the RIN. The results indicate that the efficiency of the 2nd order pump RIN to signal phase noise transfer can be more than 2 orders of magnitude higher than that from the 1st order pump. Then the performance of the dual order FW Raman configurations is compared with that of single order Raman pumping to understand trade-offs of system parameters. The nonlinear interference (NLI) noise is analyzed to study the overall OSNR improvement when employing a 2nd order Raman pump. Finally, a DWDM system with 16-QAM modulation is used as an example to investigate the benefit of DRA with dual order Raman pumping and with different pump RIN levels. We also consider a DRA system using a 1st order incoherent pump together with a 2nd order coherent pump. Although dual order FW pumping corresponds to a slight increase of linear amplified spontaneous emission (ASE) compared to using only a 1st order pump, its major advantage comes from the reduction of nonlinear interference noise in a DWDM system. Because the RIN of the 2nd order pump has much higher impact than that of the 1st order pump, there should be more stringent requirement on the RIN of the 2nd order pump laser when dual order FW pumping scheme is used for DRA for efficient fiber-optic communication. Also, the result of system performance analysis reveals that higher baud rate systems, like those operating at 100Gbaud, are less affected by pump laser RIN due to the low-pass characteristics of the transfer of pump RIN to signal phase noise.
Audrey Mockenhaupt
Using Dual Function Radar Communication Waveforms for Synthetic Aperture Radar Automatic Target RecognitionWhen & Where:
Nichols Hall, Room 246 (Executive Conference Room)
Committee Members:
Patrick McCormick, ChairShannon Blunt
Jon Owen
Abstract
Pending.
Rich Simeon
Delay-Doppler Channel Estimation for High-Speed Aeronautical Mobile Telemetry ApplicationsWhen & Where:
Eaton Hall, Room 2001B
Committee Members:
Erik Perrins, ChairShannon Blunt
Morteza Hashemi
Jim Stiles
Craig McLaughlin
Abstract
The next generation of digital communications systems aims to operate in high-Doppler environments such as high-speed trains and non-terrestrial networks that utilize satellites in low-Earth orbit. Current generation systems use Orthogonal Frequency Division Multiplexing modulation which is known to suffer from inter-carrier interference (ICI) when different channel paths have dissimilar Doppler shifts.
A new Orthogonal Time Frequency Space (OTFS) modulation (also known as Delay-Doppler modulation) is proposed as a candidate modulation for 6G networks that is resilient to ICI. To date, OTFS demodulation designs have focused on the use cases of popular urban terrestrial channel models where path delay spread is a fraction of the OTFS symbol duration. However, wireless wide-area networks that operate in the aeronautical mobile telemetry (AMT) space can have large path delay spreads due to reflections from distant geographic features. This presents problems for existing channel estimation techniques which assume a small maximum expected channel delay, since data transmission is paused to sound the channel by an amount equal to twice the maximum channel delay. The dropout in data contributes to a reduction in spectral efficiency.
Our research addresses OTFS limitations in the AMT use case. We start with an exemplary OTFS framework with parameters optimized for AMT. Following system design, we focus on two distinct areas to improve OTFS performance in the AMT environment. First we propose a new channel estimation technique using a pilot signal superimposed over data that can measure large delay spread channels with no penalty in spectral efficiency. A successive interference cancellation algorithm is used to iteratively improve channel estimates and jointly decode data. A second aspect of our research aims to equalize in delay-Doppler space. In the delay-Doppler paradigm, the rapid channel variations seen in the time-frequency domain is transformed into a sparse quasi-stationary channel in the delay-Doppler domain. We propose to use machine learning using Gaussian Process Regression to take advantage of the sparse and stationary channel and learn the channel parameters to compensate for the effects of fractional Doppler in which simpler channel estimation techniques cannot mitigate. Both areas of research can advance the robustness of OTFS across all communications systems.
Mohammad Ful Hossain Seikh
AAFIYA: Antenna Analysis in Frequency-domain for Impedance and Yield AssessmentWhen & Where:
Eaton Hall, Room 2001B
Committee Members:
Jim Stiles, ChairRachel Jarvis
Alessandro Salandrino
Abstract
This project presents AAFIYA (Antenna Analysis in Frequency-domain for Impedance and Yield Assessment), a modular Python toolkit developed to automate and streamline the characterization and analysis of radiofrequency (RF) antennas using both measurement and simulation data. Motivated by the need for reproducible, flexible, and publication-ready workflows in modern antenna research, AAFIYA provides comprehensive support for all major antenna metrics, including S-parameters, impedance, gain and beam patterns, polarization purity, and calibration-based yield estimation. The toolkit features robust data ingestion from standard formats (such as Touchstone files and beam pattern text files), vectorized computation of RF metrics, and high-quality plotting utilities suitable for scientific publication.
Validation was carried out using measurements from industry-standard electromagnetic anechoic chamber setups involving both Log Periodic Dipole Array (LPDA) reference antennas and Askaryan Radio Array (ARA) Bottom Vertically Polarized (BVPol) antennas, covering a frequency range of 50–1500 MHz. Key performance metrics, such as broadband impedance matching, S11 and S21 related calculations, 3D realized gain patterns, vector effective lengths, and cross-polarization ratio, were extracted and compared against full-wave electromagnetic simulations (using HFSS and WIPL-D). The results demonstrate close agreement between measurement and simulation, confirming the reliability of the workflow and calibration methodology.
AAFIYA’s open-source, extensible design enables rapid adaptation to new experiments and provides a foundation for future integration with machine learning and evolutionary optimization algorithms. This work not only delivers a validated toolkit for antenna research and pedagogy but also sets the stage for next-generation approaches in automated antenna design, optimization, and performance analysis.
Soumya Baddham
Battling Toxicity: A Comparative Analysis of Machine Learning Models for Content ModerationWhen & Where:
Eaton Hall, Room 2001B
Committee Members:
David Johnson, ChairPrasad Kulkarni
Hongyang Sun
Abstract
With the exponential growth of user-generated content, online platforms face unprecedented challenges in moderating toxic and harmful comments. Due to this, Automated content moderation has emerged as a critical application of machine learning, enabling platforms to ensure user safety and maintain community standards. Despite its importance, challenges such as severe class imbalance, contextual ambiguity, and the diverse nature of toxic language often compromise moderation accuracy, leading to biased classification performance.
This project presents a comparative analysis of machine learning approaches for a Multi-Label Toxic Comment Classification System using the Toxic Comment Classification dataset from Kaggle. The study examines the performance of traditional algorithms, such as Logistic Regression, Random Forest, and XGBoost, alongside deep architectures, including Bi-LSTM, CNN-Bi-LSTM, and DistilBERT. The proposed approach utilizes word-level embeddings across all models and examines the effects of architectural enhancements, hyperparameter optimization, and advanced training strategies on model robustness and predictive accuracy.
The study emphasizes the significance of loss function optimization and threshold adjustment strategies in improving the detection of minority classes. The comparative results reveal distinct performance trade-offs across model architectures, with transformer models achieving superior contextual understanding at the cost of computational complexity. At the same time, deep learning approaches(LSTM models) offer efficiency advantages. These findings establish evidence-based guidelines for model selection in real-world content moderation systems, striking a balance between accuracy requirements and operational constraints.
Past Defense Notices
PAUL LENZEN
Two-way Active Splitter for the TV BandWhen & Where:
2001B Eaton Hall
Committee Members:
James Stiles, ChairChris Allen
Glenn Prescott
Abstract
The design of a two-way active splitter requires background knowledge of discrete RF amplifier design and 3-port power divider design. These two design topics will sufficiently showcase the knowledge acquired thus far from previous graduate courses and show the ability to research/acquire the needed information to combine these two general topics into one design. The completed design will consist of a gain stage at the input of a 3-port power divider, and a gain stage at each output of the 3-port power divider. Matching networks will be required at the input/outputs of the design and also between the gain stages and 3-port power divider. The most important design considerations are: Bandwidth, Noise and Stability. The next critical design considerations are: Gain, DC requirements, S parameter flatness return loss and Group Delay. Once the NF, BW and Stability specifications are met, the amplifier will be adjusted to increase gain until the previous specs become violated. Gain is not as critical; the minimum gain required will only need to be greater than the insertion loss of the 3-port power divider and matching networks. The matching networks will be tuned to minimize NF; maximizing gain is not as important as minimizing NF. At this point the less important parameters will be verified/optimized. ADS will be used to simulate the design. The gain stage will be simulated and optimized first. Then the optimized gain stage will be added to the 3-port power divider input/outputs, along with the matching networks, to create the finalized simulation. Once the simulation of the entire design has been optimized it will be implemented similar to the simulation steps. Start with a milled PCB to test/optimize the gain stage. Then mill a PCB of the entire design and test/optimize it also. Throughout the simulation and implementation testing/optimizing the main design lessons learned/take aways will be presented and discussed. The main goal is to present the major design tradeoffs discovered throughout the design process.
PATRICK CLARK
Firewall Policy Diagram: Novel Data Structures and Algorithms for Modeling, Analysis, and Comprehension of Network FirewallsWhen & Where:
2001B Eaton Hall
Committee Members:
Arvin Agah, ChairSwapan Chakrabarti
Jerzy Grzymala-Busse
Bo Luo
Prajna Dhar
Abstract
Firewalls, network devices, and the access control lists that manage traffic are very important components of modern networking from a security and regulatory perspective. They provide the protection between networks that only wish to communicate over an explicit set of channels, expressed through the protocols, traveling over the network.
In small test environments and networks, firewall policies may be easy to comprehend and understand; however, in real world organizations these devices and policies must be capable of handling large amounts of traffic traversing hundreds or thousands of rules in a particular policy. Therefore, the need for an organization to unerringly and deterministically understand what traffic is allowed through a firewall, while being presented with hundreds or thousands of rules and routes, is imperative. This dissertation investigates the comprehension of traffic flow through these complex devices by focusing on the following research
topics:
- Expands on how a security policy may be processed by decoupling the original rules from the policy, and instead allow a holistic understanding of the solution space being represented.
- Introduces a new set of data structures and algorithms collectively referred to as a Firewall Policy Diagram (FPD). A structure that is capable of modeling Internet Protocol version 4 packet (IPv4) solution space in memory efficient, mathematically set-based entities.
- Presents a concise, precise, and descriptive language called Firewall Policy Query Language (FPQL) as a mechanism to explore the space. FPQL is a Backus Normal Form (Backus-Naur Form) (BNF) compatible notation for a query language to do just that sort of exploration. It looks to translate concise representations of what the end user needs to know about the solution space, and extract the information from the underlying data structures.
- Finally, this dissertation presents a behavioral model of the capabilities found in firewall type devices and a process for taking vendor-specific nuances to a common implementation. This includes understanding interfaces, routes, rules, translation, and policies; and modeling them in a consistent manner such that the many different vendor implementations may be compared to each other.
PURITY KIPKOECH
Performance Analysis of MANET Routing Protocols Using ns-3 Mobility ModelsWhen & Where:
246 Nichols Hall
Committee Members:
James Sterbenz, ChairRon Hui
Gary Minden
Abstract
A mobile Ad Hoc network commonly referred to as a MANET is made up of many nodes that can communicate to each other directly without the need of an access point or a central coordinator. Essentially all the nodes in the network can act either as an end system or an intermediate system. The nodes are also mobile and their movements and speed can be random thus making its network topology very dynamic due to constant link breakages and formations leading to deterioration of the performance of the MANET routing protocols. MANETs are not widely deployed and therefore mobility models are used in simulation environments to test network performance. I plan to use four of the mobility models supported in the ns-3 network simulator to show the impact of mobility on MANET routing protocols. The attributes of the nodes that will be changing are velocity and node density and the performance parameters that will be evaluated are throughput, end-to-end delay and overhead. The analysis will seek to answer the following questions: how does mobility and node density affect the performance of the different protocols? Does mobility model used affect protocol performance? Is there a superior protocol that performs better overall? And is there a mobility model that seems to offer better performance to all the protocols?
JOSE FRANCISCO FLORENCIO NETO
Receiver Antenna Array for a Multichannel Sense-and-Avoid Radar for Small UAVsWhen & Where:
2001B Eaton Hall
Committee Members:
Chris Allen, ChairRon Hui
Sarah Seguin
Abstract
A receiver monopole antenna array is designed for use in a sense-and-avoid radar for use in the Cessna C-172 and small Unmanned Aerial Vehicles (UAVs). This three element array is used for range, radial velocity and azimuthal angle calculations. After modeling and simulating it, the array is designed, implemented and finally tested in an anechoic chamber. These results are compared to both simulation and theoretical results. Since this array was designed to face harsh weather conditions, a protective dome made with ABS plastic is designed to cover it. The effects of this dome on the array’s radiation pattern are analyzed and compared to the array’s pattern without the dome.
This array has a center frequency of 1.4454 GHz and has good reflection coefficient and coupling levels for the range of frequencies tested (1.35 to 1.5 GHz). The maximum gain of its elements varies between 0 and 2.2 dB for this frequency range.
ZHI LI
Power Modeling and Optimization for GPGPUsWhen & Where:
246 Nichols Hall
Committee Members:
Xin Fu, ChairPrasad Kulkarni
Gary Minden
Abstract
State-of-the-art General-Purpose computing on Graphics Processing Unit (GPGPU) is facing severe power challenge due to the increasing number of cores placed on a chip with decreasing feature size. In order to hide the long latency operations, GPGPU employs the fine-grained multi-threading among numerous active threads, leading to the sizeable register files with massive power consumption. Exploring the optimal power savings in register files becomes the critical and first step towards the energy-efficient GPGPU design. The conventional method to reduce dynamic power consumption is the supply voltage scaling, and the inter-bank tunneling FETs (TFETs) are the promising candidates compared to CMOS for low voltage operations regarding to both leakage and performance. However, always executing at the low voltage (so that low frequency) will result in significant performance degradation. In this study, we propose the hybrid CMOS-TFET based register files. To optimize the register power consumption, we allocate TFET-based registers to threads whose execution progress can be delayed to some degree to avoid the memory contentions with other threads, and the CMOS-based registers are still used for threads requiring normal execution speed. Our experimental results show that the proposed technique achieves 30% energy (including both dynamic and leakage) reduction in register files with little performance degradation compared to the baseline case equipped with naive power optimization technique.
VICTOR JARA-OLIVARES
Enhanced Glacial Sounding Accuracy with Dual-Frequency HF RadarWhen & Where:
2001B Eaton Hall
Committee Members:
Chris Allen, ChairShannon Blunt
Dave Petr
Jim Stiles
George Tsoflias
Abstract
Radar instruments can be used to provide information on the internal and basal conditions of large and small ice masses. Radars operating in the lower part of the high frequency (HF) spectrum are required for sounding glaciers with large inclusions. Also, low-frequency sounders are useful for measuring thickness of fast-flowing glaciers in Greenland and Antarctica. This is due to the composition, attenuation, and backscattering from large pockets of water (inclusions) present in ice profile.
To radio-echo sound (RES) glaciers while providing compatibility between lightweight/portability (mass and volume) with low power consumption, we have designed, built, tested and deployed a radar for sounding glaciers requiring the trade-offs between science requirements and performance. The attenuation factors for an electromagnetic (EM) wave traveling through ice such as the extinction coefficient (Ke), the target surface scattering due to the rms height and correlation length, and the external EM noise sources, have been estimated for the design of the radar.
The HF radar used is a man-portable, dual-frequency radio-echo sounder, optimized to work in the lower half of the HF spectrum using electrically-small antennas (ESA). The radar is powered by 24 VDC provided by the use of batteries, solar panels or a portable generator capable of at least 50 W.
On July 31, 2009, the HF sounder successfully collected ice thickness data when operated at 8.75 MHz and 14.2 MHz at Jakobshavn, Greenland glacier. The present work represents the first successful survey for ice thickness using a dual-frequency technique for enhancing range accuracy. Indeed, with a single frequency time of arrival (TOA) backscattered signal the ice thickness was estimated to be 957.1 m with an estimated accuracy of 22 m. By using a second frequency TOA and the phase information at the previously estimated range at both frequencies, the target range has been re-estimated to be 952.2 m with an estimated accuracy of 8.8 m.
EHSAN HOSSEINI
Synchronization Techniques for Burst-Mode CPMWhen & Where:
250 Nichols Hall
Committee Members:
Erik Perrins, ChairShannon Blunt
Andrew Gill
David Petr
Tyrone Duncan
Abstract
Synchronization is a critical operation in digital communication systems which establishes and maintains an operational link between the transmitter and the receiver. As the advancement of digital modulation and coding schemes continues, the synchronization task becomes more and more challenging since the new standards require high-throughput functionality at low signal-to-noise ratios (SNRs). Consequently, well-established synchronization methods have to be revised and improved in order to meet the new requirements. In this research effort, we study the synchronization of continuous phase modulations (CPMs) in burst-mode communications which allow transmission of data packets to multiple users efficiently in terms of consumed power and bandwidth. Despite the attractive characteristics of CPM, its synchronization in burst-mode transmissions has not been studied well because it is a rather complex modulation with memory. In this work, we resort to data-aided techniques where a known training sequence is embedded in the burst to assist the synchronization algorithms. Therefore, the first phase of this effort is to derive the optimum training sequence for which the estimation error is minimized. The second phase consists of designing practical synchronization algorithms to resolve frequency offset, carrier phase and symbol timing ambiguities based on the observed training sequence. Finally, a hardware implementation is proposed in order to test the theoretical results in a real-world environment.
MUHARREM ALI TUNC
Optimal LPTV-Aware Bit Loading and Reduced Complexity Schemes in Broadband PLC for Smart GridWhen & Where:
250 Nichols Hall
Committee Members:
Erik Perrins, ChairShannon Blunt
Lingjia Liu
James Sterbenz
Tyrone Duncan
Abstract
Power line communication (PLC) has received steady interest over recent decades because of its economic use of existing power lines, and is one of the communication technologies envisaged for Smart Grid (SG) applications. However, since the power lines are not initially designed for data communication, the power line medium exhibits unique challanges for data communication. In particular for broadband (BB) PLC, the PLC channel shows linear periodically time varying (LPTV) behavior synchronous to the AC mains cycle, due to the time varying impedances of electrical devices that are connected to the power grid. In this research proposal, we focus on BB PLC LPTV channels, and investigate two major aspects for an orthogonal frequency division multiplexing (OFDM) system. First, we investigate the problem of optimal bit and power allocation, in order to increase throughput and improve energy e?ciency. We also provide reduced complexity mechanisms for the proposed bit loading scheme. This part constitutes the initial phase of our research. Second, we plan to tackle the problem of channel estimation for BB PLC LPTV channels and try to come up with low overhead and reduced complexity solutions, which is part of our future work that is in progress.
MEEYOUNG PARK
HealthTrust: Assessing the Trustworthiness of Healthcare Information on the InternetWhen & Where:
250 Nichols Hall
Committee Members:
Bo Luo, ChairXue-Wen Chen
Arvin Agah
Luke Huan
Yong Zeng
Abstract
Healthcare information is growing exponentially and is made more available to public. However, not all health-related information on the Internet is scientific, accurate and objective. The trustworthiness of the web information can be hardly discriminated due to the fast and augmentative properties of the Internet. Most search engines provide relevant pages to given keywords, but the results might contain unreliable or biased information. Consequently, a significant challenge associated with the information explosion is to ensure effective use of information. One way to improve the search results is by accurately identifying more trustworthy data. Surprisingly, although trustworthiness of sources is essential for a great number of daily users, not much work has been done for healthcare information sources by far. In this work, we propose a new method, HealthTrust, a new approach to automatically assess the trustworthiness of online healthcare information providers. The goal of the HealthTrust is to generalize and formalize the observations to develop a computational model that integrates topology-based and opinion-based approaches for credibility assessment of websites containing healthcare related information.
ZAID HAYYEH
Covert Networks Exploiting OFDMWhen & Where:
250 Nichols Hall
Committee Members:
Victor Frost, ChairShannon Blunt
David Petr
Erik Perrins
Jeffrey Lang
Abstract
The desire to hide communications has been around for a very long time. This includes hiding the existence of the transmission and the location of the sender. The existence of wireless networks offers another medium for these covert communications.
With many devices and networks competing for the limited spectrum, new technologies and methods are constantly sought after to increase spectral efficiency and broaden use to more devices and their bandwidth hungry applications. Orthogonal Frequency Division Multiplexing (OFDM) increases spectral efficiency when compared to Frequency Division Multiplexing (FDM). Adaptive modulation and coding (AMC), hybrid auto-repeat-request (HARQ), and opportunistic scheduling allows the system the ability to adapt to the changing environment and maintain performance. These technologies are utilized in fourth generation (4G) wireless networks such as Long Term Evolution Advanced (LITE-Advanced) and WiMAX.
This research proposes to hide a covert communications network within the RF environment of these packet based networks. We anticipate the existence of the aforementioned technologies to allow the non-covert network to adjust to the existence of the covert network. In other words, the wireless networks will view the covert network as a minor change in the RF environment. This research will also seek to measure the effect of the covert networks on the non-covert networks performance.