2009 ECE Affiliates Conference - Demo/Poster Session

Graduate Research

Senior Design Projects

Wednesday, October 14, 2009
1:00pm - Martel Hall, Duncan Hall

Graduate Research:

Demo: Axon Ethernet Device (pdf)

Student Leads: Mike Foss, Jeff Shafer, Brent Stephens
Faculty: Alan Cox and Scott Rixner

Abstract: Datacenter networks must provide low latency, fault tolerance, security, manageability, and scalability. Current hierarchical IP-Ethernet networks achieve many of these benefits but incur significant management and performance overheads.

We are developing the Axon network device to address the shortcomings of hierarchical IP-Ethernet networks. The Axon device implements transparent source routing, making the network appear as a single, large Ethernet segment to connected hosts. Inside the network, however, Axons use source-routing, eliminating Ethernet's barriers to scalability: spanning trees, traffic flooding, and distributed state. The flexibility of source-routing and the simplicity of Ethernet make an Axon network a viable replacement for hierarchical IP-Ethernet networks in the datacenter.

Demo/Poster: MMU Caching: (Quickly) Finding a Needle in a Haystack

Student Lead: Thomas W. Barr
Faculty: Alan L. Cox and Scott Rixner

Abstract: Virtual memory support allows multiple programs to address memory locations as if they were they were the only program running on a system. The operating system manages a table, called a 'page table', that specifies where each virtual memory location is actually stored in the underlying physical memory space. As programs have began to use more and more memory, these tables have become very complex and increasingly slow to read. In fact, the processor can spend almost half its time consulting these tables for some real life applications. As such, fast caches have been developed by both AMD and Intel for these tables. We have examined and defined the design space for these 'MMU caches', and propose new points in the space which have superior performance, area efficiency and flexibility to differing applications.

Demo/Poster: Power Modeling and Color Transformation of Graphical User Interfaces on OLED Displays

Student Lead: Mian Dong
Faculty: Lin Zhong

Abstract: Emerging organic light-emitting diode (OLED)-based displays obviate external lighting; and consume drastically different power when displaying different colors, due to their emissive nature. This creates a pressing need for OLED display power models for system energy management, optimization as well as energy-efficient GUI design, given the display content or even the graphical user interface (GUI) code. In this work, we study this opportunity using commercial QVGA OLED displays and user studies. We first present a comprehensive treatment of power modeling of OLED displays, providing models that estimate power consumption based on pixel, image, and code, respectively. These models feature various tradeoffs between computation efficiency and accuracy so that they can be employed in different layers of a mobile system. We validate the proposed models using a commercial QVGA OLED module and a mobile device with a QVGA OLED display. Then, based on the models, we propose techniques that adapt GUIs based on existing mechanisms as well as arbitrarily under usability constraints. Our measurement and user studies show that more than 75% display power reduction can be achieved with user acceptance.

Demo: Cooperative Partial Detection Test Setup (pdf)

Student Leads: Michael Wu, Kia Amiri
Faculty: Joseph Cavallaro

Abstract: Cooperative communication with multi-antenna relays can signicantly increase the reliability and speed. However, cooperative MIMO detection would impose considerable complexity overhead onto the relay if a detect-and-forward (FDF) strategy is employed. In order to address this challenge, we propose a novel cooperative partial detection (CPD) strategy to partition the detection task between the relay and the destination. CPD utilizes the inherent structure of the tree-based sphere detectors, and modifies the tree traversal so that instead of visiting all the levels of the tree, only a subset of the levels, thus a subset of the transmitted streams, are visited. Based on this methodology, the destination combines the source signal and the partial relay signal to perform the detection step. Using the CPD approach, the relay can avoid the considerable overhead of MIMO detection while helping the source-destination link to improve its performance.

Demo: BeamSwitch: Directional Communication on Mobile Devices and its Application to Energy Conservation

Student Leads: Ardalan Amiri Sani, Hasan Dumanli
Faculty: Lin Zhong, Ashutosh Sabharwal

Abstract:

Demo: Synchronized CSMA: Model and Implementation (pdf)

Student Lead: Ehsan Aryafar
Faculty: Edward Knightly

Abstract: A class of CSMA protocols used in a broad range of wireless applications uses synchronized contention where nodes periodically contend at intervals of fixed duration. While several models exist for asynchronous CSMA contention used in protocols like IEEE 802.11 MAC, no model exists for synchronized CSMA contention that also incorporates realistic factors like clock drifts. In this paper, we introduce a model that quantifies the interplay of clock drifts with contention window size, control packet size, and carrier sense regulated by usage of guard time. Using an FPGA-based MAC protocol implementation and controlled experiments on a wireless testbed we evaluate the model predictions on the isolated and combined impact of these key performance factors to per-flow throughput and fairness properties in both single-hop and multi-hop networks. Our model and experimental evaluation reveal conditions on protocol parameters under which the throughput of certain flows can exponentially decrease; while at the same time, it enables solutions that can offset such problems in a predictable manner.

Demo: FPGA Prototyping of a High Data Rate LTE Uplink Baseband Receiver (pdf)

Student Lead: Guohui Wang, Bei Yin, Kia Amiri, Michael Wu
Faculty: Joseph Cavallaro

Abstract: The Third Generation Partnership Project(3GPP) Long Term Evolution (LTE) standards is becoming the appropriate choice to pave the way for the next generation wireless and cellular standards. While the popular OFDM technique has been adopted and implemented in previous standards and also in the down link LTE, it suffers from high peak-to-average-power ratio(PAPR). High PAPR required more sophisticated power amplifiers in the handsets and would result in lower efﬁciency PAs. In order to combat such effects, the uplink LTE choice of transmission is the novel Single Carrier Frequency Division Multiple Access(SC-FDMA) scheme which has lower PAPR due to its inherent signal structure. While reducing the PAPR, the SC-FDMA requires a more complicated detector structure in the base station for multi-antenna and multi-user scenarios. Since the multi-antenna and multi-user scenarios are critical part of the LTE standard to deliver high performance and data rate, it is important to design novel architectures to ensure high reliability and data rate in the receiver. We propose an architecture as well as the ﬁrst FPGA prototype for an LTE uplink receiver with two receive antennas. The prototype is to be implemented on the Rice Wireless Open-access Research Platform (WARP).

Demo/Poster: Infrared trace gas sensing technologies for environmental, biomedical and industrial applications

Team Members: Jim Doty, Lei Dong, Rafal Lewicki, David Thomazy, and Bernadeta Wysocka (MIRTHE)
Faculty: Anatoliy Kosterev and Frank Tittel

Abstract: Recent advances in the development of sensors based on the use of diode and quantum cascade lasers for the sensitive, selective detection and quantification of both small and large molecular gas species with resolved and unresolved spectroscopic features respectively will be show cased. Different spectroscopic techniques have been employed such as laser absorption spectroscopy and quartz enhanced photoacoustic spectroscopy (QEPAS). Applications include concentration measurements of single and multiple trace gas species for applications in such diverse fields as environmental monitoring, industrial process control and medical diagnostics. In this demo we will focus on several examples of real world sensor applications, which include fire and post fire detection in spacecraft habitats. A poster depicts the design and performance evaluation of a QEPAS based acetylene sensor. A second poster describes a modular, wide spectral range QEPAS trace gas sensor based on a near-infrared telecom distributed-feedback diode laser. This research is partially funded by a National Science Foundation Engineering Center grant for Mid-Infrared Technology for Health and the Environment (MIRTHE).

Demo: Laboratory for Nanophotonics

Poster: Light Bending Nanoparticles
Poster: Reshaping the Plasmonic Properties of an Individual Nanoparticle

Authors: Nicholas King, Shaunak Mukherjee, J. Britt Lassiter, Mark Knight, Nikolay Mirin
Faculty: Naomi Halas

Abstract: Metallic nanostructures with their geometry-dependent optical resonances are a topic of intense current interest due to their ability to manipulate light in ways not possible with conventional optical materials. When symmetry is broken in plasmonic nanostructures, new optical properties emerge. We have recently fabricated reduced symmetry nanocup structures by two different techniques. One is by controllably reshaping an individual Au nanoshell into a reduced-symmetry nanoegg, then a semishell or nanocup. The second technique is by electron beam deposition of metal on silica nanospheres and lifting it off the substrate. We follow the changes in the plasmonic response at the single nanostructure level, and observe the splitting of plasmon modes and the onset of electroinductive plasmons upon controlled, incremental opening of the outer metallic layer of the nanoshell. We show that Au nanocups at their magnetoinductive resonance have the unique ability to redirect scattered light in a direction dependent on cup orientation, as a true three-dimensional nanoantenna.

Demo: Connexions: Transforming Engineering Education

Abstract: Connexions is a global, interconnected, reusable repository of textbooks, teaching materials and learning materials, founded by Rice University ECE faculty member Rich Baraniuk in 1999. Since then the repository has grown to nearly 15,000 items woven into 900 textbooks, courses, journals, and other learning materials. The National Science Foundation and ECE corporate sponsor, National Instruments funded the creation and dissemination of engineering education materials resulting in more than 30 collections covering subjects from Applied Probability to Electrical Engineering. Corporate sponsors Texas Instruments, National Instruments use Connexions for teaching materials geared toward hardware and software used in engineering education, and the IEEE Signal
Processing Society is using Connexions for a major initiative to develop a critical mass of signal processing educational modules and courses
that will be available for free access by anyone, anywhere, at any time. In this poster session we will highlight the impact these materials are having on engineering education at Rice and around the world.

Poster: Hybrid Relaying for the Parallel Relay Network (pdf)

Student Author: Samantha Summerson
Faculty: Behnaam Aazhang

Abstract: Although cooperation in wireless networks is known to improve communication in many aspects, efficient relay selection remains an open problem. We analyze a wireless network which employs multiple parallel relays to assist in communication between a single source-destination pair, demonstrating that gains are achieved when the relays selected form a random set as compared to utilizing a deterministic set of relays. We assume that no direct link exists between the source and destination and the system is time-slotted. Relays are selected to actively participate in transmission based on their instantaneous channel magnitudes, which implies that the relays chosen to participate in a block of time is stochastic. Three relaying options are considered: Amplify-and-Forward (AF), Decode-and-Forward (DF), and no relaying (entering an idle state). The efficient allocation of resources, namely bandwidth and power, is considered for both perfect feedback from the destination to the relays and no feedback. From our information theoretic analysis we conclude that by integrating known relaying protocols to create a hybrid protocol we can increase the performance of multiple-relay networks in terms of achievable rates and probability of outage when measured against using only AF or DF relaying.

Poster: Resource Allocation in Multiflow Wireless Networks (pdf)

Student Author: Gareth Middleton
Faculty: Behnaam Aazhang

Abstract: In wired networks, scheduling and routing is a well-posed and largely solved problem. This is not so in the TDMA wireless case. The broadcast nature of the wireless channel complicates the scheduling by introducing interference, while unpredictable channel fading introduces variability into routing decisions and requires power control at all nodes. These issues are all greatly magnified when considering scheduling and routing multiple information flows. The problem of choosing the optimal schedule, routes, and power allocations so as to maximize average throughput for all flows is NP-Complete and requires an exhaustive search over an exponential space.

In this work, we present an approximation of this problem and a solution technique which runs in polynomial time. We first define a class of problems for which this approximation holds, and then exploit the structure of this class to employ successive dynamic programming methods. The class includes the problem of maximizing throughput for each flow, and also that of minimizing total end-to-end delay, and applies for arbitrary network topologies and resource availability.

Poster: Bargaining for Energy-efficient User Cooperation

Student Author: Matthew Nokleby
Faculty: Behnaam Aazhang

Abstract: User cooperation can improve performance in wireless systems, but it requires other users to expend energy acting as relays. When energy is scarce, users have incentive to refuse to cooperate in order to conserve resources. Therefore, we investigate cooperative communications from an energy-efficiency perspective. We present a cellular framework in which two mobile users, who desire to communicate with a common base station, may cooperate via decode-and-forward relaying. We define the achievable bits-per-energy region and characterize the power allocations associated with its boundary points. In order to find an approach that gives selfish users incentive to cooperate, we apply game theory, finding the power allocations that achieve the Nash bargaining solution. Numerical results indicate that the Nash bargain provides a fair and efficient compromise, and that both users obtain noticeably improved bits-per-energy efficiency via user cooperation.

Poster: Acumen: An Environment for Rapid Prototyping of Cyber-physical systems

Student Authors: Angela Zhu, Marisa Peralta, Jun Inoue, Travis Martin, Henry Gorman
Postdoc/Staff: Edwin Westbrook, Alexandre Chaptout
Faculty: Marcia O'Malley, Walid Taha

Abstract: Cyber-Physical Systems (CPS) combine discrete and continuous physical processes. Developing a new cyber-physical system is an iterative process that involves design, simulation, prototyping, and production. Writing simulation code using current tech- niques is time consuming. Our thesis is that a carefully designed, domain-speciﬁc language can alleviate this diffculty. To demonstrate this thesis, we designed and implemented a prototype of a novel simulation environment called Acumen. The centerpiece of Acumen is a physical description language called PhyDL, which allows the user to directly describe dynamic equations governing the system being modeled, making the writing of simulation code much easier for engineers. A series of auto- matic transformations convert the high-level descriptions into a form that is directly machine executable. This poster presents the design of PhyDL and several case stud- ies of using PhyDL for designing CPS systems, which show that PhyDL is accurate and easy to use for domain experts.

Poster: Medium Access Protocol Design and Analysis: An Error-event Approach

Student Author: Pedro Santacruz
Faculty: Ashutosh Sabharwal

Abstract: In this work we take a new perspective on the multiple access scenario and rethink the way in which we analyze the performance of different communication mechanisms. We take a more holistic approach by looking at system performance across the physical and network layers. The motivation for this work comes from the observation that, in the wireless multiple access setting, errors might be caused by different types of sources. We approach this new perspective by reverse engineering the inner workings of random access protocols. We identify how these processes contribute to the successful transmission of data by analyzing them as distributed algorithms. Our method for evaluation of these algorithms hinges on the identification of events that cause errors. We present the new procedure to analyze random access protocols and examples on the application of the technique.

Poster: Paranoid Secondary: Power-control for Bursty Cognitive Interference Channel (pdf)

Student Author: Debashis Dash
Faculty: Ashutosh Sabharwal

Abstract: Cognitive wireless is a promising approach to improve the spectral efficiency of underutilized wireless networks and at the same time be compatible with legacy systems. We derive optimal schemes for a secondary user when a passive primary with a fixed single user encoder- decoder structure is operating below capacity over a common interference channel (IC). We show that the optimal secondary strategy falls back to the single user design for a subset of weak or moderate IC, and to a multi-user interference cancellation design for strong IC. Otherwise, the optimal strategy is to split the secondary into two virtual users, one which treats the primary as noise and the other uses interference cancellation. We show that the rate regions are non-convex due to the lack of user cooperation. Additionally, if the primary user has bursty data, the secondary senses the channel at the beginning of each block to estimate the state of the primary. The key issue here is the change in the expected noise of the channel as seen by the secondary when it is not sensing. We show that the optimal power profile for the secondary is found by water-filling across the parallel channels with varying expected noise. Depending on the sensed state of the primary, the optimal power profile is either growing or decaying. This paranoid power profile of the secondary is the side effect of the lack of information about the idle channel slots. Finally we extend these results to the noisy sensing and give genie-aided and no-sensing bounds.

Poster: Impact of Network Topology Knowledge on Fairness: A Geometric Approach

Student Author: David Kao
Faculty: Ashutosh Sabharwal

Abstract: We examine how the precision of network topology knowledge impacts the achievable degree of max-min fairness. We focus on time-division multiple access (TDMA) networks, and employ a model based on physical-layer eventsthat sufficiently describes the topology effects with respect to TDMA. Using Jain’s fairness index, we characterize the fairness loss resulting from allocation of resources (in our case time-divisions) based on imprecise knowledge of topology. We find loss is more pronounced when a single link has low signal-to-noise ratio (SNR); i.e. links which have poor throughput also make the allocation more unfair. Conversely, our analysis suggests that if the relative error in estimating link qualities is identical for all links in the network, no one link dominates the fairness loss..

Poster: Statistical IC design using sensitivity analysis (pdf)

Student Author: Masoud Rostami
Faculty: Kartik Mohanram

Abstract: In this work, an efficient algorithm will be proposed to perform gate sizing considering the statistical variations of chip's physical parameters. In the first step, gates are short-listed to reduce the computational dimensions to an affordable size. Sensitivity of circuit delay to the aforementioned short-list of gates is used to augment the traditional convex formulation of gate sizing. In comparison with other methods, the proposed algorithm is faster and has shown a good performance on a wide range of benchmarks.

Poster: Graphene polarity controllable amplifier and its applications

Student Authors: Xuebei Yang and Masoud Rostami
Faculty: Kartik Mohanram

Abstract: This work exploits the unique ambipolar conduction property of graphene field effect transistors to realize a single transistor polarity controllable amplifier. The amplifier is polarity controllable since its small signal gain can be switched between positive and negative modes through proper biasing. Polarity controllable amplifiers can greatly simplify communication circuits in applications such as phase shift keying and phase detection that traditionally use complicated analog multipliers. We also propose a robust design that addresses issues of unmatched performance in gain and output DC levels in the two modes, even in the presence of non-idealities due to contact resistance and asymmetric drive currents.

Poster: I-Slate : Probabilistically Designed Device for Point-of-Care Education (pdf)

Student Author: Avinash Lingamneni
Faculty: Krishna Palem
Collaborators: Al Barr, Vincent Mooney, Rajeswari Pingali, Harini Sampath, Jayanthi Sivaswamy

Abstract: In this project, the design of an ultra-low energy and low cost sustainable educational device, called the interactive and intelligent slate, or I-Slate is proposed. It is based on the revolutionary concept of probabilistic hardware design and of Ethnomathematics with an aim to improve literacy in developing countries - with an emphasis on India as the first test, focusing on grades 1-5. The pioneering principle of trading accuracy of electronics for energy is at the heart of probabilistic hardware design, wherein the answers to the calculations performed by the electronics for processing video or graphics need not be precise and it drives the design of I-Slate’s hardware architecture, while educational pedagogy and practice drive the software design. Energy and concomitant environmental sustainability are the overarching themes that encompass all aspects of this effort.

Poster: Efficient coupling between on-chip and on-board optical waveguides

Student Author: Jie Shu
Faculty: Qianfan Xu

Abstract: We propose an efficient coupling structure which can couple between highly confined silicon-on-insulator waveguide on chip and larger polymer waveguide for board-level optical interconnections. Instead of conventional butt-coupling, we use an adiabatic taper that is flip-chip bonded on top of a polymer waveguide. Through the taper, optical wave gradually couples from a sub-micron silicon waveguide to a micron-sized polymer waveguide. We show that the tolerance of misalignment between the taper and the polymer waveguide is as high as 5 microns for less than 0.7-dB coupling loss, which allows the coupling to be done with high throughput and low cost by commercial pick-and-place equipments. We also present a design of the shape of the taper in order to minimize the taper length.

Poster: SaVE: Sensor-assisted motion estimation for efficient H.264/AVC video encoding

Student Author: Ahmad Rahmati
Faculty: Lin Zhong
Collaborators (National University of Singapore): Xiaoming Chen, Zhendong Zhao, Ye Wang

Abstract: Motion estimation is a key component of modern video encoding and is very compute-intensive. We present a novel Sensor-assisted Video Encoding (SaVE) method to reduce the computational complexity of motion estimation in H.264/AVC encoders, leveraging accelerometers and digital compasses that are increasingly available on mobile devices. Using these sensors, SaVE calculates the rotational movement of a camera and then infers the global motion in the camera image sensor; it subsequently employs the estimated global motion to simplify the state-of-the-art motion estimation algorithms, UMHS and EPZS used in H.264/AVC encoders. We have constructed a prototype of SaVE and report extensive evaluation of it. Our experimental results show that SaVE can reduce the computations of UMHS and EPZS algorithms by up to 27% and 18%, respectively, while achieving the same or better video quality.

Poster: Exploring High Level Algorithmic Synthesis: A Case Study of LDPC Decoder Design Using HLS (pdf)

Student Author: Yang Sun
Faculty: Joseph Cavallaro

Abstract: We present a scalable and low power low-density parity-check (LDPC) decoder design for the next generation wireless handset SoC. The methodology is based on high level synthesis: PICO (program-in chip-out) tool was used to produce efficient RTL directly from a sequential untimed C algorithm. Based on the PICO technology, we have synthesized, placed, and routed a two-layer pipelined decoder on a TSMC 65nm 0.9V 8-metal layer CMOS technology with a core area of 1.2 mm2. The maximum achievable throughput is 415 Mbps when operating at 400 MHz clock frequency and the estimated peak power consumption is 180 mW.

Poster: Methods for analyzing the activity of neuronal populations from in-vivo two-photon calcium image data

Student Author: Eva Dyer
Faculty: Richard Baraniuk, Don Johnson, Andreas Tolias (BCM)

Abstract: Measuring the activity of neuronal populations, at the resolution of a single cell, has proven to be an important yet difficult challenge. An emerging experimental technique, known as two-photon calcium imaging, is capable of capturing the activity of hundreds of neurons, but the aliasing introduced by the temporal resolution of these systems, in addition to the high-levels of photon shot noise introduced by the acquisition process, make the problem of inferring the spiking activity of each cell within the population very challenging. The effects of noise become exacerbated when imaging large populations, as the effective signal-to-noise ratio over the field-of-view is dramatically reduced. In order to infer the spiking activity of cells, from noisy and corrupted observations, we first learn a model that describes the relationship between the spiking activity of a cell and our observations. Upon learning this model, we cast the problem of spike inference as a sparse approximation problem and use ell-1 minimization to infer the underlying spiking activity of every cell within the population.

Poster: Localization via Compressive Sensing

Student Author: Andrew Waters
Faculty: Richard Baraniuk
Researchers: Volkan Cevher, Petros Boufounos
Collaborators: Anna Gilbert, Martin Strauss (University of Michigan)
Abstract: We exploit recent results in compressive sensing to aid in the problem of geolocalizing targets in a wireless sensor network. Localization typically requires each sensor to send large snapshots of its observed signal around the network which, in turn, causes a severe drain on both power and communication bandwidth. In our approach, we send a small number of compressive measurements across the network to ease these communication burdens while still providing accurate localization estimates.

Poster: QCL based Mid-IR microscopy system for tissue imaging

Student Author: Benjamin Appiah
Faculty: Rebekah Drezek

Abstract: We have designed and assembled a mid-infrared microscope for use in the imaging of biological tissues. This setup uses a continuous wave quantum cascade laser (QCL) as the source of illumination. The laser operates at a wavelength of about 8.2um (1220cm-1) at room temperature. The setup utilizes low F/# lenses up to f/0.5; these high numerical apertures lenses have recently become commercially viable at increasingly lower costs and hence contribute towards the development of low cost systems. An f/0.5 aspheric ZnSe lens is employed in a setup intended for cellular imaging, and an f/1 CAF2 lens is implemented for imaging protein structures and fibers in human tissue.

Poster: Lightweight user authentication with a single tri-axis accelerometer (pdf)

Student Author: Jiayang Liu
Faculty: Lin Zhong

Abstract: We report a series of user studies that evaluate the feasibility and usability of light-weight user authentication with a single tri-axis accelerometer. We base our investigation on uWave, a state-of-the-art recognition system for user-created free-space manipulation, or gestures. Our user studies address two types of user authentication: non-critical authentication (or identification) for a user to retrieve privacy-insensitive data; and critical authentication for protecting privacy-sensitive data. For non-critical authentication, our evaluation shows that uWave achieves high recognition accuracy (98%) and its usability is comparable with text ID-based authentication. Our results also highlight the importance of constraints for users to select their gestures. For critical authentication, the evaluation shows uWave achieves state-of-the-art resilience to attacks with 3% false positives and 3% false negatives, or 3% equal error rate. We also show that the equal error rate increases to 10% if the attackers see the users performing their gestures. This shows the limitation of gesture-based authentication and highlights the need for visual concealment.

Poster: Soft Information in a three node network

Student Author: Corina Serediuc
Faculty: Behnaam Aazhang

Abstract: Reliable transmission in a wireless environment has always been a challenge. One solution to improve reliability is to use a relay to aid in the communication, thus using a cooperative communications system. A relay protocol defines the processing performed by a relay on the signal it receives from a source. Three common protocols are used in wireless communication systems: decode-and-forward (DF), amplify-and-forward (AF) and estimate-and-forward (EF), also known as compress-and-forward or quantize-and-forward. An EF protocol is characterized by the soft information sent by the relay to the destination and the processing algorithm of the received signals at the destination node (i.e., the decision rule). We investigate the performance of the cooperative system using an expected value as the soft information and compare it with other relaying protocols as AF and DF. We apply the proposed EF protocol to the canonical three-node cooperative network and assume additive white Gaussian noise (AWGN) channels. Using the bit error rate (BER) as a metric, we conclude that EF outperforms AF and DF, for a pathloss model in which we use BPSK modulation.

Poster: Exploiting Channel Symmetry in Two-way Channels

Student Author: Justin Fritz
Faculty: Behnaam Aazhang

Abstract: Wireless communication is frequently employed for the bi-directional exchange of information between devices with disparate capabilities. Most current two-way wireless links are between mobile units and either access points for wireless local area network (WLAN) or basestations for third generation long term evolution and WiMax. These basestations or access points are typically stationary with relaxed constraints on size, weight and power consumption relative to the mobile units with small form factors. Asymmetry of constraints results in asymmetry of the cost of computation and make multiple antennas more feasible at the stationary unit. This disparity in cost motivates efforts to shift signal processing such as channel estimation and equalization from cost sensitive nodes to those with more relaxed constraints. In this work we propose a precoding scheme, two-way training, and channel estimation that shifts all the computation involved in dealing with multiplicative channel gain as well as frequency selective channels to the basestaion or access point. This work demonstrates the first tractable implementation of a precoding based transceiver scheme of this class on the Rice University Wireless Open Access Research Platform (WARP). This scheme will lend itself to immediate implementation on cellular phones and personal wireless devices resulting in reduced complexity and cost of devices as well as prolonging the battery life.

Poster: Robust Stable Radiometric Fingerprinting for Wireless Devices (pdf)

Student Author: Ovunc Kocabas
Faculty: Farinaz Koushanfar

Abstract: We introduce a new method for radiometric ﬁngerprinting that detects the unique variations in the antenna,oscillator properties, as well as the digital and analog interfaces of the radio by passively monitoring the radio packets. Several individual identiﬁers are used for extracting the unique physical characteristics of the radio, including the frequency offset, mod- ulated phase offset, in-phase/quadrature-phase offset from the origin, and magnitude. Our method provides stable and robust identiﬁcation by developing individual identiﬁers (classiﬁers) that may each be weak (i.e., incurring a high prediction error) but their committee can provide a strong classiﬁcation technique. We use two methods for combining the classiﬁers: (1) weighted voting, and (2) maximum likelihood. Our hardware implementation and experimental evaluations over multiple radios demonstrate that our weighted voting approach can identify the radios with an average of 88% detection probability and an average of 12.8% probability of false alarm after testing only 5 frames. The probability of detection and probability of false alarms both rapidly improve by increasing the number of test frames.

Poster: TFA Wireless – Networking Research for Underserved Communities

Student Authors: Stanislav Miskovic, Anastasios Giannoulis
Faculty: Edward Knightly

Abstract: TFA Wireless is a joint project of the Rice Networks Group and the non-profit, Technology-For-All (TFA). The project was initiated with two main goals: (i) to empower one of the most economically disadvantaged Houston neighborhoods via means of communication, and (ii) to enable breakthrough wireless networking research. In four years of operation, the TFA Wireless network has served more than 4000 clients, which gained computer literacy, searched for jobs, monitored their health, improved their education, kept in touch with their relatives living abroad via voice and email services, etc.

The network also expanded frontiers of wireless research far beyond analytical models and wireless testbeds. Our research identified significant improvements to almost all state-of-the-art networking mechanisms: rate adaptation, routing, client mobility support, overhead reduction, etc. Today, our results not only enable higher throughputs of wireless communication, but also protect investments in capacity of wireless networks. In our poster, we present some of our key research results..

Poster: Plasmonic Nanorod Absorbers as Orientation Sensors (pdf)

Student Author: Ji Won Ha, Liane Slaughter
Postdoc: Wei-Shun Chang
Faculty: Stephan Link

Abstract: Nanoparticles are actively exploited as biological imaging probes. Of particular interest are gold nanoparticles because of their non-blinking and non-bleaching absorption and scattering properties that arise from the excitation of surface plasmons. Nanoparticles with anisotropic shapes furthermore provide information about the probe orientation and its environment. Here we show how the orientation of single gold nanorods (25x73 nm) can be determined from both the transverse and longitudinal surface plasmon resonance by using polarization sensitive photothermal imaging. By measuring the orientation of the same nanorods separately using scanning electron microscopy we verified the high accuracy of this plasmon absorption based technique. However, care had to be taken when exciting the transverse plasmon absorption using a large numerical aperture objective as out-of-plane plasmon oscillations were also excited then. For the size regime studied here, being able to establish the nanorod orientation from the transverse mode is unique to photothermal imaging and almost impossible with conventional dark-field scattering spectroscopy. This is important because the transverse surface plasmon resonance is mostly insensitive to the medium refractive index and nanorod aspect ratio allowing nanorods of any length to be used as orientation sensors without changing the laser frequency.

Senior Design Projects (New Feature):

Senior Design Project: Where's the Bus?

Team Members: Bailey Basile (ELEC), Alysha Jeans (ELEC), Katherine Threlkeld (ELEC)
Faculty Mentor: Jim Young

Abstract: Currently, Rice University ahs an extensive shuttle system covering several routes, each running on a different schedule. Predicting when a certain bus will arrive at a stop is difficult, especially for busses that run less frequently. Our project will aim at making students' bus-riding experiences faster and more convenient by providing data as to busses' current locations and predicted arrival times. We are building on the work of a previous senior design team who laid the foundation for a tracking system utilizing RFID technology. Our main goal is to develop a user interface for this system so that it can be implemented at Rice.

Senior Design Project: Video Trolley for Gait Analysis

Team Members: Ashley Hill (MEMS), Lara Liem (MEMS), Michelle Pyle (MEMS), Jon Stanley (ELEC)

Faculty Mentor: Gary Woods
Corporate Mentor: Steve Irby, Shriners Hospital for Children

Abstract: Gait analysis helps doctors diagnose walking problems in their patients and determine the next course of action, which may involve multiple surgical procedures to perform at one setting. The Motion Analysis Lab at Shriners Hospital for Children has a need for a video feed of a consistent sagittal view of a moving patient. A video trolley system can produce the necessary video feed by automatically tracking the motions of a patient with a moving video camera on a fixed one-dimensional track. The system makes use of video motion tracking software and a bidirectional motor control system that drives a camera-mounted trolley. A good video recording of the sagittal view could make all the difference in the speedy recovery of the patient.

Senior Design Project: BluefraRed

Team Members: Kevin Choi (ELEC), Jose Hernandez (ELEC), Samuel Kim (ELEC), Lucia Sun (ELEC)

Faculty Mentor: Lin Zhong
Corporate Mentor: Jehan Wickramasuriya, Motorola

Abstract: A hardware implementation that converts Bluetooth signals to infrared. Users that have mobile devices with Bluetooth capability will be able to control their home audio/video appliances using the mobile device instead of their home remotes. We plan to research the Bluetooth and infrared protocols and demonstrate their implementation by sending out BT and IR signals.

Senior Design Project: Emergency Radio TV Receiver (pdf)

Team Members: Michael Foree (ELEC), Christopher Eagleson (ELEC), Daniel Valvano (ELEC)

Faculty Mentor: J.D. Wise

Abstract: Victims of natural disasters often lose power for an extended length of time. Some people rely on battery powered radios and televisions to keep up with the latest news. Unfortunately, the switch to digital broadcast television has rendered old battery powered televisions obsolete, and decoding digital signals in an urban, multipath environment is a power intensive task. Team TeleAudio proposes a self-powered product that plays the audio and/or closed caption track of the television signal. This product should use less power than existing portable televisions since it does not have a lighted screen and does not need to process video.

Currently, we are in the process of deciding type of output (headphone, speaker, LCD with scrolling closed caption), antenna (internal, fold out, roof mounted), power source (battery cartridge, hand crank, solar, combination), and extra features (AM/FM radio, MP3 playback capability, closed caption memory storage, clock, flashlight, etc).

Senior Design Project: IGVC Obstacle Mapping Outdoor Robot

Team Members: Frank Chen (ELEC), Shamoor Anis (ELEC), Chris Ertel (MECH), Wally Kelly (MECH)

Faculty Mentors: J.D. Wise and Gary Woods
External Mentor: Andrew Lynch, Rice Robotics Club

Abstract: In this poster, we will display a possible design for the sensor component of the Intelligent Ground Vehicle Competition (IGVC) robot that our senior design group is responsible for. The specifications will be indicated as well as how we propose to meet those requirements in order to improve the chances of successful navigation of an obstacle course by a robot. A sketch of the possible obstacles and format of the competition will be presented in order to indicate the challenges we will encounter and how we plan to solve detecting the obstacles with an integration of various sensor systems.

Senior Design Project: Remote Performance Monitoring in TFA Network (pdf)

Team Members: Joe Cavazos (ELEC), Jash Guo (ELEC), Michael Lo (ELEC), Nik Maureira (ELEC)

Faculty Mentor: Edward Knightly
External Mentor: Anastasios Giannoulis

Abstract: The Rice TFA network is a state-of-the-art, multi-hop wireless network that has been made available to approximately 4,000 users in an underserved Houston neighborhood. However, tools that gauge the end user's quality of service do not exist. Our senior design project aims to develop a user experience framework which will measure network performance within this network, and to the internet. After determining the correct networking metrics which represent user experience, we will then implement software for both end users and network administrators.

Senior Design Project: Gesture-Based Remote Control

Team Members: Maxime Paul (ELEC), Jaimeet Gulati (ELEC), Ryan Pei (ELEC), Tate Hornbeck (ELEC)

Faculty Mentor: Lin Zhong, Gary Woods
Corporate Mentor: Jehan Wickramasuriya, Motorola

Abstract: Today's home entertainment is provided by complicated, multi-component theatre systems as well as media focused PCs. As of now there does not exist a coherent, comprehensive means of controlling these systems. The current method, a simple, linear remote control, has been outdated for many years. There has been many technological advances in sensor technology since the invention of the remote. Even now we work with remote controls and have to deal with complicated, time-wasting menus, and a simple "point and click" interface. We are developing a remote control to better suit our mobile and computerized world. We are going to design a remote that is capable of controlling not only a traditional home entertainment system, but also a personal computer for use with "Hulu" and other media players. We feel that the most natural and efficient way for humans to interact with these devices is through the use of gestures. Working with the three-axis accelerometer of mobile phones (i.e. Blackberrys, iPhones, etc.) and Dr. Zhong's uWave software, we will develop a method to use gesture based controls, possibly combined with voice and touch commands to provide increased remote controllability.

Senior Design Project: 3D Model Extractor

Team Members: Robert LiKamWa (ELEC), Ben Bahorich (MechE), John Cate (CAAM)

Faculty Mentors: Mark Embree and Lin Zhong

Abstract: Our Senior Design Project group seeks to find a cheap and easy way to obtain 3D models of real-life objects. Interior designers and game programmers would benefit from the ability to manipulate digital 3D objects. Even the casual computer user would enjoy the experience of playing around with 3D models of objects in digital environments. However, it is rather difficult and time-consuming to generate these models. We seek to create an inexpensive user-friendly device to work with a computer and capture a 3D model of an object. This will provide all users with the ability to create and manipulate 3D models.

Senior Design Project: Guitar Effects Processor

Team Members: Ricardo Frank Barrera (ELEC), Kyle Barnhart (ELEC), Seth O'Brien (ELEC/COMP)

Faculty Mentors: Joseph Cavallaro
Corporate Mentor: Michael Brogioli, Freescale Semiconductor

Abstract: Today's guitar effect pedals are implemented as rugged, bulky analog circuits that must be manually switched in order to turn the effects on and off. Digital variations of these effect pedals do exist but they are expensive, rather large and cannot achieve the high fidelity of analog effect petals. Our project goal is to implement these sorts of effects on a DSP chip in real time, while designing our effects box to avoid the shortcomings of analog and digital effects pedals currently on the market. Furthermore, we will be automating the distortion, auto-tuning the play and harmonize with other instruments all in real time. The novel part is that one person can because a one man band for the most part. Imagine, playing a C chord with your electric guitar and automatically having a C for a bass or an acoustic guitar ring out in the background as well.