RITE Site Project Descriptions: Summer 2001
1.
Advanced Components for Mobile and Optical Communication Systems
Prof. A. Iliadis
In this project Micro-Electro-Mechanical Systems (MEMS) technology is employed to miniaturize antennas for mobile communication platforms. Antennas will be modeled and their design optimized for sizes suitable for monolithic integration with personal communication cards and hand held units. Emphasis is placed on developing new geometries and using novel materials deposited by Pulsed Laser Deposition (PLD) such as oxides and metallic compounds, both for the efficient propagation and containment (shielding, isolation) of the signals. MEMS technology and PLD deposition will be applied for the processing and fabrication of these "chip" form antennas.
Current mobile communication hand held units use an analog front-end receiver/transmitter amplifier design that down-shifts (or up-shifts for emission) to an intermediate frequency compatible to the digital signal processor (DSP) unit that then processes the in-coming (or out-going) signals. In this project we study the conditions under which the DSP can be brought to the front end of the system, the specific requirements of the system in terms of shielding, power, and frequency response.
Students will have the opportunity to learn the intricate details of antenna design, use software to model and simulate wave propagation, develop processing and fabrication skills, and understand the properties of novel materials critical to the development of the next generation of microelectronics systems. Furthermore, students will examine and evaluate different circuit design approaches, introduce novel absorbing and shielding materials, and interact with industry.
2.
Computational Models of the Human Auditory System
Prof. S. Shamma
Over the last few years, Prof. Shamma's group has conducted summer projects with several undergraduates dealing with how the auditory system processes sound, from the ear up to the brain. Projects suitable for RITE participants are those involving the use of an extensive library of auditory signal processing algorithms and graphics dedicated to speech and music analysis and editing. Developed in MATLAB at the University, this package includes help and graphics features, as well as sophisticated interfaces and interactive capabilities that make it particularly easy to use by undergraduates. In using this software, students focus initially on the basic description of the processing stages and their underlying concepts, treating the computational elements as black boxes. They learn first how to perform various useful operations on sound signals such as transformations between time and frequency domains, conditioning, morphing sentences into each other, and altering voices. Once they acquire familiarity and facility with the package, they move on to examine the underlying principles behind each command and operation. In the process, students learn how to use MATLAB commands, various linear system concepts and operations, filtering, and some nonlinear transformations. In many cases, particularly interested and bright students may go on to create new algorithms (albeit simple), to modify existing ones, or to invent new applications ranging from recognition of musical instruments to the synthesis of music and speech.
The projects described above are fully supported by extensive computational and laboratory facilities at the Neural Systems Laboratory.
3.
Computer Recognition of Faces
Prof. Rama Chellappa
Computer recognition of faces has applications in access control, ATM machines and in human/computer interfaces. In the project, the student(s) will develop global principal component analysis/linear discriminant analysis or feature-based approaches for verifying the presence/absence of a human and then determine the human's gender, identity and emotions. Using images acquired by a camera mounted on a PC, the algorithms will be able to produce an electronic log of the human's arrival/departure record. Emphasis will be placed on real-time implementations of existing algorithms in Professor Chellappa's group.
4.
GPS-Based Location Determination
Prof. P. S. Krishnaprasad
The nucleus of a GPS (global positioning laboratory) has been set up within the Intelligent Servosystems Laboratory, a joint facility of the Electrical and Computer Engineering Department and the Institute for Systems Research. This is the outgrowth of projects and courses on GPS Theory and Technology over the period 1997-1999. At the present time the lab includes a mobile remote controlled platform (actually a meter long radio-controlled car equipped with an internal combustion engine), with on-board Novatel GPS receiver, and a Novatel base station receiver, and telemetry channel enabling differential, carrier-sensed GPS positioning to an accuracy of 2 cm, based on commercial and hand-crafted estimation algorithms. The new algorithms are being developed by a Ph.D student and an undergraduate student is involved in ongoing experimental work.
GPS represents a remarkable integration of several major advances in the field of electrical engineering--from satellite communication, coding, estimation of signals in noise, to real-time signal processing via fast, low power circuitry on portable devices--providing us the capability to determine with increasing precision and accuracy, the location and speed of a GPS-equipped platform practically anywhere on earth. Emerging practical applications of this technology range from high accuracy surveying for geographical information systems (GIS), high-precision geodesy for earth science, to accurate navigation and flight control of aircraft, personal and commercial land vehicles, autonomous farm equipment, autonomous mobile robotics, to name a few. Bringing this technology to the attention of undergraduate students would be useful in strengthening the empirical base and technical preparedness of a typical student.
It is expected that initially, work in the proposed project would emphasize a view of the integration of subject matter inherent to GPS, demonstrating how systems concepts, such as filtering algorithms (e.g. Kalman filters and various nonlinear filters), mathematical descriptions of orbital mechanics of satellites, and differential or interferometric techniques, and phase tracking techniques contribute to the advances in precision and accuracy achievable via GPS. Electrophysical aspects with an impact on a variety of noise/error phenomena (ionospheric distortions, foliage-induced loss-of-lock and multipath) have to be dealt with properly in a successful GPS system. The project will also provide opportunities for studying applications of GPS to motion control, and in this context also investigate integration of a variety of other sensor technologies (example inertial and optical/acoustic proximity sensors) with GPS for this purpose. It is expected that initially, work in the proposed project would emphasize a view of the integration of subject matter inherent to GPS, demonstrating how systems concepts, such as filtering algorithms (e.g. Kalman filters and various nonlinear filters), mathematical descriptions of orbital mechanics of satellites, and differential or interferometric techniques, and phase tracking techniques contribute to the advances in precision and accuracy achievable via GPS. Electrophysical aspects with an impact on a variety of noise/error phenomena (ionospheric distortions, foliage-induced loss-of-lock and multipath) have to be dealt with properly in a successful GPS system. The project will also provide opportunities for studying applications of GPS to motion control, and in this context also investigate integration of a variety of other sensor technologies (example inertial and optical/acoustic proximity sensors) with GPS for this purpose. Students selected under the RITE site program will be able to pursue software development in this arena (with interesting challenges in integer optimization for phase ambiguity resolution, cycle slip detection and mode switching in satellite tracking). A primary goal of the project will be for students to learn the principles and carry out implementations of motion determination algorithms based on filtering and estimation theory and gain a better appreciation of issues in signal processing influenced by noise characteristics associated to the GPS system.
5.
Opto-Impulse
Radio for High Data Rate Wireless Communications
Prof. Chi Lee
The objective of this research is to achieve high information data rate (multi-Mbs/s to Gbs/s) wireless communications with low probability of detection (LPD) and low probability of interception (LPI). The approach employed is the ultra-wideband impulse radio using optoelectronic technique. The innovation includes the use of picosecond semiconductor lasers and ultrafast photoconductive switches for impulse generation and reception. We refer this new technology as opto-impulse radio. We expect that opto-impulse radio will revolutionize wireless communications with quantum jump in system performance. The proposed research for the NSF RITE students covers only hardware related issues. Students will be asked to set-up and demonstrate a simple opto-impulse radio system.
6.
Network Security for Emerging Broadband Networks
Dr. Patrick Dowd
As the world becomes more connected, the need for advancement in network security has become crucial. Network security mechanisms need to be developed to keep pace with this very exciting environment. It is not just the advancement in terms of network speed - it is also the integration of voice, video and data on the same network. Voice over IP is extremely important and is expected to become a dominant vehicle for voice transport. This project will develop security methods to protect voice traffic in an IP-based (internet) like environment, and will also study the interface between the SS7 public switched telephone network (PSTN) to the IP network. The goal is to develop mechanisms for high speed fire walling and network intrusion detection in this context. This project will have both experimental and theoretical components. The experimental testbed will be ATDnet/MONET - a multi-gigabit WDM research network that is located in the Washington DC area. The research project will build from a current research project on high speed firewalling for broadband networks and will also include the participation of a major telecommunications company.
7.
High
Data Rate Fiber-Optic Communication Research
Prof. Julius Goldhar
nvestigation of physical limitations to very high bit rate fiber optic communications: Possible research topics include: characterization of the transmission lines, development of opto-electronic components for generation, regeneration and detection various types high bit rate signals. Experimental work will be conducted at the Laboratory for Physical Science, a US Department of Defense research laboratory affiliated with the University of Maryland.
8.
Optical Wireless
Prof. C. C. Davis
We are engaged in a program of research designed to improve the performance of line of sight optical communication links (optical wireless) through the atmosphere along paths relatively close to the ground. These links must perform in the face of varying degrees of atmospheric turbulence and obscuration. The principal difficulties in achieving high data rate and low bit-error-rate performance with such links are discussed. A series of studies is ongoing, which involve new modulation approaches, sources, and coding schemes to deal with problems such as fading, tracking and pointing, and various system engineering issues. Specifically, our program of research can be summarized as follows:
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Studies of fade statistics on realistic urban-based line-of-sight ranges.
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Studies of atmospheric chirality
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Studies of Polarization Shift Keying and Polarization Diversity for fade resistance, and channel capacity doubling.
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Tests of delayed, orthogonal channel polarization diversity for fade resistance.
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Bit-error-rate measurements at high (1Gb/s and above) data rates.
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Development and testing of forward error correcting codes for turbulent channels.
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System engineering involving transmitter/receiver design, and aperture averaging.
9.
Optical Fiber Biosensors
Prof. C. C. Davis
Recent development of extremely small, tapered optical fiber probes for hybridization based biosensing promises the capability for real-time, in-situ, detection of bioagents. We are working to optimize the performance of near-field optical probes within small diameter capillaries for this purpose. These sensors use miniaturized, adiabatically tapered single-mode optical fibers, with end diameters as small as 50 nm. The reduced diameter region of the fiber is gradually tapered so as to appear almost cylindrical under a microscope. The silica surface of the fiber is treated in a series of chemical reactions that allow the covalent attachment of oligonucletide probes whose base sequences are complementary to signature genes of a bioagent (bacterium or virus). In work so far a fluorescent-labeled probe was used to detect gene expression in a sandwich assay. The labeled gene then hybridized with the oligonucleotides bound on the fiber surface placing the fluorophore in the evanescent field of the guided wave in the fiber. The evanescent wave has an optical field that is guided by the fiber, but lies outside the fiber so that it can excite fluorophores only on, or very near, the fiber surface. Evanescent waves do not radiate and only extend about a half wavelength from the fiber surface. The resultant fluorescence is collected by the fiber and returned to a wavelength-selective detection system. Although evanescent waves are guided by a fiber, these waves do not couple from one fiber to another in a bundle, so the use of evanescent field excitation allows the bundling of fibers and the subsequent detection of multiple genes simultaneously. We have demonstrated that this system has sensitivity on the order of 100 femtomole/ml for fluorescent-labeled oligonucleotide DNA or Helicobacter pylori RNA and that the sensor responds in a matter of seconds. H. Pylori has been associated with various intestinal problems and stomach cancer, and in our sensor was detected through its ribosomal RNA. We are planning studies of “molecular beacons” as the fluorescent labels in the sensor, which could potentially eliminate the need for fluorescently labeled probes for detection. These sensors will detect in real-time, the presence of signature genes in samples, obtained for example, by air-sampling and subsequent lysis of collected biomaterial. This work is carried out in a collaboration with Professor William Bentley of the Department of Chemical Engineering and would give students an opportunity to work in the exciting bioengineering area.
10.
Near-Field Measurements of Antennas Relevent to Cellular Communications
Prof. C. C. Davis
In a collaboration with the Food and Drug Administration (FDA) we are developing procedures to make accurate measurements of field strengths and Specific Absorption Rates (SARs) in the proximity of cell phones. This work is aimed at verifying the performance of cell phone antennas, and demonstrating that they are in compliance with Federal Communications Committee ( FCC) guidelines. In these measurements a cell phone type antenna is placed in close proximity to a tank loaded with dielectric liquid designed to mimic the dielectric properties of the human head. A scanning probe arrangement makes E-field and SAR measurements as a function of position near the antenna. This project gives students an opportunity to become familiar with radiofrequency/microwave (RF/MW) hardware and measurement techniques.