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Electrical Engineering and Computer Science

Defense Notices

EECS MS and PhD Defense Notices for

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


GOUTHAM SELVAKUMAR - Constructing an Environment and Providing a Performance Assesment of Android's Dalvik Virtual Machine on x86 and ARM

MS Project Defense (CS)

When & Where:
June 7, 2013
10:00 am
250 Nichols Hall
Committee Members:
Prasad Kulkarni, Chair
Victor Frost
Xin Fu

Abstract: [ Show / Hide ]
Android is one of the most popular operating systems (OS) for mobile touchscreen devices, including smart-phones and tablet computers. Dalvik is a process virtual machine (VM) that provides an abstraction layer over the Android OS, and runs the Java-based Android applications. The first goal of this project is to construct a development environment for conveniently investigating the properties of Android's Dalvik VM on contemporary x86 and ARM architectures. The normal development environment restricts the Dalvik VM to run on top of Android, and requires an updated Android image to be built and installed on the target device after any change to the Dalvik code. This update-build-install process unnecessarily slows down any Dalvik VM exploration. We have now discovered a (undisclosed) configuration that enables us to study the Dalvik VM as a stand-alone application on top of the Linux OS.
The second goal of this project is to understand the translation/compilation sub-system in the Dalvik VM, experiment with various modifications to determine the best translation parameters, and compare the Dalvik VM's just-in-time (JIT) compilation characteristics (such as quality of code generated and compilation time) on the x86 and ARM systems with a state-of-the-art Java VM. As expected, we find that JIT compilation is able to significantly improve application performance over basic interpretation. Comparing Dalvik's generated code quality with the Java HotSpot VM, we observe that Dalvik's ARM target is a much more mature compared to Dalvik-x86. However, Dalvik's simple trace-based compilation generates code quality that is much worse as compared to HotSpot. Finally, our experiments also reveal the most effective JIT compilation parameters for the Dalvik VM, and its effect of benchmark performance and memory usage.


ADAM CRIFASI - Framework of Real-Time Optical Nyquist-WDM Receiver using Matlab and Simulink

MS Thesis Defense (EE)

When & Where:
June 3, 2013
10:30 am
2001B Eaton Hall
Committee Members:
Ron Hui, Chair
Shannon Blunt
Erik Perrins

Abstract: [ Show / Hide ]
I investigate an optical Nyquist-WDM Bit Error Rate (BER) detection system. A transmitter and receiver system is simulated, using Matlab and Simulink, to form a working algorithm and to study the effects of the different processes of the data chain. The inherent lack of phase information in the N-WDM scheme presents unique challenges and requires a precise phase recovery system to accurately decode a message. Furthermore, resource constraints are applied by a cost-effective Field Programmable Gate Array (FPGA). To compensate for the speed, gate, and memory constraints of a budget FPGA, several techniques are employed to design the best possible receiver. I study the resource intensive operations and vary their resource utilization to discover the effect on the BER. To conclude, a full VHDL design is delineated, including peripheral initialization, input data sorting and storage, timing synchronization, state machine and control signal implementation, N-WDM demodulation, phase recovery, QAM decoding, and BER calculation.


TIANCHEN LI - Radar Cross-Section Enhancement of a 40 Percent Yak54 Unmanned Aerial Vehicle

MS Project Defense (EE)

When & Where:
May 31, 2013
2:00 pm
2001B Eaton Hall
Committee Members:
Chris Allen, Chair
Ken Demarest
Ron Hui

Abstract: [ Show / Hide ]
With increasing civilian use of unmanned aerial vehicles (UAVs), flight safety of these unmanned devices in populated area has become one of the most concerned issues among the operators and users. To reduce the rate of colliding, anti-collision systems based on airborne radar system and enhanced autopilot programs are developed. However, for most civilian UAVs being made of non-metal materials which has considerably low radar cross-section (RCS), those UAVs are really hard or even impossible to be detected by radars. This project aims to design a light-weight UAV mounted RCS enhancement device that can increase the visibility of the UAV for airborne radars which work in the frequency band near
1.445 GHz. In this project, a 40% YAK54 radio controlled UAV is used as the subject UAV. The report also concentrates on the design of passive Van Atta Array reflector approach.


REID CROWE - Development and Implementation of a VHF High Power Amplifier for the Multi-Channel Coherent Radar Depth Sounder/Imager System

MS Thesis Defense (EE)

When & Where:
May 31, 2013
10:30 am
317 Nichols Hall
Committee Members:
Fernando Rodriguez-Morales, Chair
Chris Allen
Carl Leuschen

Abstract: [ Show / Hide ]
This thesis presents the implementation and characterization of a VHF high power amplifier developed for the Multi-channel Coherent Radar Depth Sounder/Imager (MCoRDS/I) system. MCoRDS/I is used to collect data on the thickness and basal topography of polar ice sheets, ice sheet margins, and fast-flowing glaciers from airborne platforms. Previous surveys have indicated that higher transmit power is needed to improve the performance of the radar, particularly when flying over challenging areas.
The VHF high power amplifier system presented here consists of a 50-W driver amplifier and a 1-kW output stage operating in Class C. Its performance was characterized and optimized to obtain the best tradeoff between linearity, output power, efficiency, and conducted and radiated noise. A waveform pre-distortion technique to correct for gain variations (dependent on input power and operating frequency) was demonstrated using digital techniques.
The amplifier system is a modular unit that can be expanded to handle a larger number of transmit channels as needed for future applications. The system can support sequential transmit/receive operations on a single antenna by using a high-power circulator and a duplexer circuit composed of two 90° hybrid couplers and anti-parallel diodes. The duplexer is advantageous over switches based on PIN-diodes due to the moderately high power handling capability and fast switching time. The system presented here is also smaller and lighter than previous implementations with comparable output power levels.




Past Defense Notices


KENNETH DEWAYNE BROWN - A Mobile Wireless Channel State Recognition Algorithm

PhD Dissertation Defense (EE)

When & Where:
May 22, 2013
2:00 pm
2001B Eaton Hall
Committee Members:
Glenn Prescott, Chair
Chris Allen
Gary Minden
Erik Perrins
Richard Hale*

Abstract: [ Show / Hide ]
The scope of this research is a blind mobile wireless channel state recognition (CSR) algorithm that detects channel time and frequency dispersion. Hidden Markov Models (HMM) are utilized to represent the statistical relationship between these hidden channel dispersive state process and an observed received waveform process. The HMMs provide sufficient sensitivity to detect the hidden channel dispersive state process. First-order and second-order statistical features are assumed to be sufficient to discriminate channel state from the receive waveform observations. State hard decisions provide sufficient information, and can be combined, to increase the reliability of a time block channel state estimate. To investigate the feasibility of the proposed CSR algorithm, this research effort has architected, designed, and verified a blind statistical feature recognition process capable of detecting whether a mobile wireless channel is coherent, single time, single frequency, or dual dispersive. Channel state waveforms are utilized to compute the transition and output probability parameters for a set of feature recognition HMMs. Time and frequency statistical features are computed from consecutive sample blocks and input into the set of trained HMMs which compute a state sequence conditional probability for each feature. The conditional probabilities identify how well the input waveform statistically agrees with the previous training waveforms. Hard decisions were produced from each feature state probability estimate and combined to produce a single output channel dispersive state estimate for each input time block. To verify the CSR algorithm performance, combinations of state sequence blocks were input to the process and state recognition accuracy was characterized. Initial results suggest that CSR based on blind waveform statistical feature recognition is feasible.


WENRONG ZENG - Content-Based Access Control

PhD Comprehensive Defense (CS)

When & Where:
May 17, 2013
4:00 pm
250 Nichols Hall
Committee Members:
Bo Luo, Chair
Arvin Agah
Jerzy Grzymala-Busse
Prasad Kulkarni
Alfred Tat-Kei Ho*

Abstract: [ Show / Hide ]
In conventional database access control models, access control policies are explicitly specified for each role against each data object manually. Nowadays, in large-scale content-centric data sharing,
conventional approaches could be impractical due to exponential explosion and the sensitivity of data objects. In this proposal, we first introduce Content-Based Access Control (CBAC), an innovative access control model for content-centric information sharing. As a complement to conventional access control models, the CBAC model makes access control decisions based on the content similarity between user credentials and data content automatically. In CBAC, each user is allowed by a meta-rule to access “a subset” of the designated data objects of the whole database, while the boundary of the subset is dynamically determined by the textual content of data objects. We then present an enforcement mechanism for CBAC that exploits Oracle’s Virtual Private Database (VPD). To further improve the performance of the proposed approach, we introduce a content-based blocking mechanism to improve the efficiency of CBAC enforcement to further
reveal a more relavant part of the data objects comparing with the user credentials and data content. We also utilized a tagging mechanism for more accurate textual content matching for short text snippets (e.g. short VarChar attributes) to extract topics other than pure word occurences to
represent the content of data. Experimental results show that CBAC makes reasonable access control decisions with a small overhead.


MARIANNE JANTZ - Detecting and Understanding Dynamically Dead Instructions for Contemporary Machines

MS Thesis Defense (CS)

When & Where:
May 16, 2013
2:00 pm
246 Nichols Hall
Committee Members:
Prasad Kulkarni, Chair
Xin Fu
Man Kong

Abstract: [ Show / Hide ]
Instructions executed by the processor are dynamically dead if the values they produce are not used by the program. Researchers have discovered that a surprisingly large fraction of executed instructions are dynamically dead. Dynamically dead instructions (DDI) can potentially slow-down program execution and waste power. Unfortunately, although the issue of DDI is well-known, there has not been any comprehensive study to understand and explain the occurence of DDI, evaluate its performance impact, and resolve the problem, especially for contemporary architectures.
The goals of our research are to quantify and understand the properties of DDI, as well as, systematically characterize them for existinng state-of-the-art compilers and popular architectures in order to develop compiler and/or architectural techniques to avoid their execution at runtime. In this thesis, we describe our GCC-based framework to instrument binary programs to generate control-flow and data-flow (registers and memory) traces at runtime. We present the percentage of DDI in our benchmark programs, as well as, characteristics of the DDI. We display that context information can have a siginificant impact on the probability that an instruction will be dynamically dead. We show that a low percentage of static instructions actually contribute to the overall DDI in our benchmark programs. We also describe the outcome of our manual study to analyze and categorize the instances of dead instructions in our x86 benchmarks into seven distinct categories. We briefly describe our plan to develop compiler and architecture based techniques to eliminate each category of DDI in future programs. And finally, we find that x86 and ARM programs, compiled with GCC, generally contain a significant amount of DDI. However, x86 programs present fewer DDI than the ARM benchmarks, which display similar percentages of DDI as earlier research for other architectures. Therefore, we suggest that the ARM architecture observes a non-negligible fraction of DDI and should be examined further. Overall, we believe that a close synergy between static code generation and program execution techniques may be the most effective strategy to eliminate DDI.


YUHAO YANG - Protecting Attributes and Contents in Online Social Networks

PhD Comprehensive Defense (CS)

When & Where:
May 16, 2013
11:00 am
2001B Eaton Hall
Committee Members:
Bo Luo, Chair
Arvin Agah
Luke Huan
Prasad Kulkarni
Alfred Tat-Kei Ho*

Abstract: [ Show / Hide ]
With the extreme popularity of online social networks, security and privacy issues become critical. In particular, it is important to protect user privacy without preventing them from normal socialization. User privacy in the context of data publishing and structural re-identification attacks has been well studied. However, protection of attributes and data content was mostly neglected in the research community. While social network data is rarely published, billions of messages are shared in various social networks on a daily basis. Therefore, it is more important to protect attributes and textual content in social networks.

We first study the vulnerabilities of user attributes and contents, in particular, the identifiability of the users when the adversary learns a small piece of information about the target. We have presented two attribute-reidentification attacks that exploit information retrieval and web search techniques. We have shown that large portions of users with online presence are very identifiable, even with a small piece of seed information, and the seed information could be inaccurate.
To protect user attributes and content, we will adopt the social circle model derived from the concepts of “privacy as user perception” and “information boundary”. Users will have different social circles, and share different information in different circles. We propose to automatically identify social circles based on three observations: (1) friends in the same circle are connected and share many friends in common; (2) friends in the same circle are more likely to interact; (3) friends in the same circle tend to have similar interests and share similar content. We propose to adopt multi-view clustering to model and integrate such observations to identify implicit circles in a user’s personal network. Moreover, we propose an evaluation mechanism that evaluates the quality of the clusters (circles).
Furthermore, we propose to exploit such circles for cross-site privacy protection for users –new messages (blogs, micro-blogs, updates, etc) will be evaluated and distributed to the most relevant circle(s). We monitor information distributed to each circle to protect users against information aggregation attacks, and also enforce circle boundaries to prevent sensitive information leakage.


MICHAEL JANTZ - Automatic Cross-Layer Framework to Improve Memory Power and Efficiency

PhD Comprehensive Defense (CS)

When & Where:
May 13, 2013
9:30 am
246 Nichols Hall
Committee Members:
Prasad Kulkarni, Chair
Xin Fu
Andy Gill
Bo Luo
Karen Nordheden*

Abstract: [ Show / Hide ]
Recent computing trends include an increased focus on power and energy consumption and the need to support multi-tenant use cases in which physical resources need to be multiplexed efficiently without causing performance interference. Many recent works have focused on how to best allocate CPU, storage and network resources to meet competing service quality objectives and reduce power. At the same time, data-intensive computing is placing larger demands on physical memory systems than ever before. In comparison to other resources, however, it is challenging to obtain precise control over distribution of memory capacity, bandwidth, or power, when virtualizing and multiplexing system memory. That is because these effects intimately depend upon the results of activity across multiple layers of the vertical execution stack, which are often not available in any individual component.

The goal of our proposed work is to exercise collaboration between the compiler, operating system, and memory controller for a hybrid memory architecture to reduce energy consumption, while balancing performance trade-offs. Analysis, data structure partitioning, and code layout transformations will be conducted by the compiler and two-way communication between the applications and OS will guide memory management. The OS, together with the hardware memory controller, will allocate, map, and migrate pages to minimize energy consumption for a specified performance tolerance.


NIRANJAN SUNDARARAJAN - Study of Balanced and Unbalanced RFID Tags Attached to Charge Pumps

MS Project Defense (EE)

When & Where:
May 10, 2013
1:00 pm
246 Nichols Hall
Committee Members:
Ken Demarest, Chair
Dan Deavours
Jim Stiles

Abstract: [ Show / Hide ]
Ultra High frequency Radio Frequency Identification (UHF RFID) technology has gained wide prominence in recent years. The main drawback of a UHF RFID tag antenna is that it is sensitive to the environment in which it is placed. That is the performance of a RFID tag deteriorates when placed on conductive or dielectric objects. Most UHF RFID antennas use variations of a balanced folded dipole, such as a T-match antenna. In this project, we answer the question, would it be beneficial having an unbalanced version of a T-match antenna (Gamma match antenna) in a RFID tag compared to having a conventional balanced T-match antenna? To test this we analyzed the performance of a gamma match and T-match antenna, when attached to a charge pump, which generally acts as a load for a RFID antenna in a RFID tag. Also, we propose a procedure to find out the best impedance to drive a charge pump and outline a simple procedure to design a balanced T-match antenna for any desirable input impedance. Later, we transform a balanced T-match antenna into a unbalanced Gamma match antenna and tested to see that a Gamma match antenna is able to deliver more power and voltage to a charge pump than a T-match antenna. Finally we validate these results by studying and comparing the Z-parameters of a Gamma match and T-match antenna.


HARIPRASAD SAMPATHKUMAR - A Framework for Information Retrieval and Knowledge Discovery from Online Healthcare Social Networks

PhD Comprehensive Defense (CS)

When & Where:
May 8, 2013
9:30 am
246 Nichols Hall
Committee Members:
Bo Luo, Chair
Xue-Wen Chen, Co-Chair
Jerzy Grzymala-Busse
Prasad Kulkarni
Jie Zhang*

Abstract: [ Show / Hide ]
Information used to assist biomedical research has largely comprised of data available in published sources like scientific literature or clinical sources like patient health records. Information from such sources, though extensive and organized, is often not readily available due to its proprietary and/or privacy-sensitive nature. Collecting such information through clinical and pharmaceutical studies is expensive and the information is limited to the diversity of people involved in the study. With the growth of Web 2.0, more and more people openly share their health experiences with other similar patients on healthcare related social networks. The data available in these networks can act as a new source that provides for unrestricted, high volume, highly diverse and up-to-date information needed for assisting biomedical and pharmaceutical research. However, this data is often unstructured, noisy and scattered, making it unsuitable for use in its current form. The goal of this research is to develop an Information Retrieval and Knowledge Discovery framework that is capable of automatically collecting such data from online healtcare networks, extracting useful information and representing it in a form that would facilitate knowledge discovery in biomedical and pharmaceutical research. Information retrieval, Text mining and Ontology modeling techniques are employed in building this framework. An Adverse Drug Reaction discovery tool and a patient profiling tool are being developed to demonstrate the utility of this framework.


SRINIVAS PALGHAT VISWANATH - Design and Development of a Social Media Aggregator

MS Project Defense (CoE)

When & Where:
May 7, 2013
3:00 pm
2001B Eaton Hall
Committee Members:
Fengjun Li, Chair
Victor Frost
Prasad Kulkarni

Abstract: [ Show / Hide ]
There are so many social network aggregators available in the market, e.g.SocialNetwork.in, FriedFeed, Pluggio, Postano, Hootsuite etc. A social network aggregator is a one-stop shop which provides a single point of entry to manage operations of multiple social network accounts and keep track of social media streams. Once a user establishes the sites credentials onto the aggregator, it pulls static data like user profile information, dynamic data like news feed and user posts.

This project aims to design a unified interface of static and dynamic data from facebook, foursquare and twitter for a particular user. Unlike other social aggregators that display dynamic social media stream data in different tabs, each corresponding to a social networking site, we merge dynamic data like timeline from facebook and sent tweets from twitter together and display them on a single stream sorted according to the posting date. Similarly, news feed from facebook and twitter home are merged together and can be seen on a single stream. To simplify cross-social-network management, we support unified operations such as Posting. New posts/tweets can be easily posted at the same time on both the sites through this application. User can further specify the access privileges (i.e., seen by public, friends, friends of friends or only me) of the posts on Facebook, for dynamic privacy protection.

Least but not last, this aggregator supports integration of user profiles from the three social networks. An edit distance based similarity score is calculated to determine the likelihood of profiles from three social networks belong to a same friend. For those with a perfect score, the matched profiles are combined and displayed in an additional dialog.


BRIGID HALLING - Towards a Formal Verification of the Trusted Platform Module

MS Thesis Defense (CS)

When & Where:
May 3, 2013
3:00 pm
250 Nichols Hall
Committee Members:
Perry Alexander, Chair
Andy Gill
Fengjun Li

Abstract: [ Show / Hide ]
The Trusted Platform Module (TPM) serves as the root-of-trust in a trusted computing environment, and therefore warrants formal specification and verification. This thesis presents results of an effort to specify and verify an abstract TPM 1.2 model using PVS that is useful for understanding the TPM and verifying protocols that use it. TPM commands are specified as state transformations and sequenced to represent protocols using a state monad. Preconditions, postconditions, and invariants are specified for individual commands and validated. All specifications are written and verified automatically using the PVS decision procedures and rewriting system.


ANNETTE TETMEYER - A POS Tagging Approach to Capture Security Requirements within an Agile Software Development Process

MS Thesis Defense (CS)

When & Where:
April 24, 2013
10:00 am
2001B Eaton Hall
Committee Members:
Hossein Saiedian, Chair
Arvin Agah
Prasad Kulkarni

Abstract: [ Show / Hide ]
Software use is an inescapable reality. Computer systems are embedded into devices from the mundane to the complex and significantly impact daily life. Increased use expands the opportunity for malicious use which threatens security and privacy. Factors such as high profile data breaches, rising cost due to security incidents, competitive advantage and pending legislation are driving software developers to integrate security into software development rather than adding security after a product has been developed. Security requirements must be elicited, modeled, analyzed, documented and validated beginning at the initial phases of the software engineering process rather than being added at later stages. However, approaches to developing security requirements have been lacking which presents barriers to security requirements integration during the requirements phase of software development. In particular, software development organizations working within short development lifecycles (often characterized as agile lifecyle) and minimal resources need a light and practical approach to security requirements engineering that can be easily integrated into existing agile processes.
In this thesis, we present an approach for eliciting, analyzing, prioritizing and developing security requirements which can be integrated into existing software development lifecycles for small, agile organizations. The approach is based on identifying candidate security goals, categorizing security goals based on security perspectives, understanding the stakeholder goals to develop preliminary security requirements and prioritizing preliminary security requirements. The identification activity implements part of speech tagging to scan requirements artifacts for security terminology to discover candidate security goals. The categorization activity applies a general security perspective to candidate goals. Elicitation activities are undertaken to gain a deeper understanding of the security goals from stakeholders. Elicited goals are prioritized using risk management techniques and security requirements are developed from validated goals. Security goals may fail the validation activity, requiring further iterations of analysis, elicitation, and prioritization activities until stakeholders are satisfied with or have eliminated the security requirement. Finally, candidate security requirements are output which can be further modeled, defined and validated using other approaches. A security requirements repository is integrated into our proposed approach for future security requirements refinement and reuse. We validate the framework through an industrial case study with a small, agile software development organization.


PAUL LENZEN - Two-way Active Splitter for the TV Band

MS Project Defense (EE)

When & Where:
April 23, 2013
2:00 pm
2001B Eaton Hall
Committee Members:
James Stiles, Chair
Chris Allen
Glenn Prescott

Abstract: [ Show / Hide ]
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 Firewalls

PhD Dissertation Defense (CS)

When & Where:
April 19, 2013
12:30 pm
2001B Eaton Hall
Committee Members:
Arvin Agah, Chair
Swapan Chakrabarti
Jerzy Grzymala-Busse
Bo Luo
Prajna Dhar*

Abstract: [ Show / Hide ]
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 Models

MS Project Defense (CoE)

When & Where:
April 19, 2013
11:00 am
246 Nichols Hall
Committee Members:
James Sterbenz, Chair
Ron Hui
Gary Minden

Abstract: [ Show / Hide ]
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 FLORENCI0 NETO - Receiver Antenna Array for a Multichannel Sense-and-Avoid Radar for Small UAVs

MS Project Defense (EE)

When & Where:
April 17, 2013
11:00 am
2001B Eaton Hall
Committee Members:
Chris Allen, Chair
Ron Hui
Sarah Seguin

Abstract: [ Show / Hide ]
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 GPGPUs

MS Thesis Defense (CoE)

When & Where:
April 8, 2013
8:30 am
246 Nichols Hall
Committee Members:
Xin Fu, Chair
Prasad Kulkarni
Gary Minden

Abstract: [ Show / Hide ]
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 Radar

PhD Dissertation Defense (EE)

When & Where:
April 1, 2013
3:30 pm
2001B Eaton Hall
Committee Members:
Chris Allen, Chair
Shannon Blunt
Dave Petr
Jim Stiles
George Tsoflias*

Abstract: [ Show / Hide ]
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 CPM

PhD Comprehensive Defense (EE)

When & Where:
January 18, 2013
10:00 am
250 Nichols Hall
Committee Members:
Erik Perrins, Chair
Shannon Blunt
Andrew Gill
David Petr
Tyrone Duncan*

Abstract: [ Show / Hide ]
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 Grid

PhD Comprehensive Defense (EE)

When & Where:
January 16, 2013
2:00 pm
250 Nichols Hall
Committee Members:
Erik Perrins, Chair
Shannon Blunt
Lingjia Liu
James Sterbenz
Tyrone Duncan*

Abstract: [ Show / Hide ]
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 Internet

PhD Comprehensive Defense (CS)

When & Where:
January 11, 2013
1:00 pm
250 Nichols Hall
Committee Members:
Bo Luo, Chair
Xue-Wen Chen, Co-chair
Arvin Agah
Luke Huan
Prasad Kulkarni
Yong Zeng*

Abstract: [ Show / Hide ]
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.