Engineering Commons^™

Correlation Between Eut Failure Levels And Esd Generator Parameters, Jayong Koo, Qing Cai, Kai Wang, J. Maas, T. Takahashi, Andrew Martwick, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Some system-level electrostatic discharge (ESD) tests repeat badly if different ESD generators are used. For improving repeatability, ESD generator specifications have been changed, and modified generators have been compared in a worldwide round robin test. The test showed up to 1 : 3 variations of failure levels. Multiple parameters that characterize ESD generators have been measured. This paper correlates the parameters to test result variations trying to distinguish between important and nonrelevant parameters. The transient fields show large variations among different ESD generators. A correlation has been observed in many equipment under tests (EUTs) between failure levels and the spectral …

A Variable-Order Flom Algorithm For Heavy-Tailed Clutter Suppression, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

The normalized fractionally-lower order moment (FLOM) algorithm exhibits fast convergence but high excess mean squared error (MSE) when the order is less than 2. This paper proposes a method using variable order moments to adaptively changing the order during adaptation, thus achieving both fast initial convergence and low excess MSE in the steady state. The algorithm is applied to both Gaussian and heavy-tailed non-Gaussian clutter suppression in phased array applications. The results show better performances of the proposed algorithm over the normalized FLOM and normalized Least Mean Square (NLMS) algorithms. The proposed algorithm also performs well in other adaptive filtering …

On Control System Design For The Conventional Mode Of Operation Of Vibrational Gyroscopes, Lili Dong, Qing Zheng, Zhiqiang Gao

Electrical and Computer Engineering Faculty Publications

This paper presents a novel control circuitry design for both vibrating axes (drive and sense) of vibrational gyroscopes, and a new sensing method for time-varying rotation rates. The control design is motivated to address the challenges posed by manufacturing imperfection and environment vibrations that are particularly pronounced in microelectromechanical systems (MEMS) gyroscopes. The method of choice is active disturbance rejection control that, unlike most existing control design methods, does not depend on an accurate model of the plant. The task of control design is simplified when the internal dynamics, such as mechanical cross coupling between the drive and sense axes, …

A C-Band Scatterometer Simultaneous Wind/Rain Retrieval Method, David G. Long, Congling Nie

Faculty Publications

Using collocated ERS scatterometer (ESCAT), Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), and European Centre for Medium-Range Weather Forecasts (ECMWF) data, the effects of rain on ESCAT wind-only retrieval are evaluated. Additional scattering from rain causes estimated wind speeds to appear higher than expected. Selected directions of the rain-corrupted wind vectors are biased toward along-track directions under conditions of heavy rain, which is regardless of the true wind direction. Rain becomes more significant for data acquired at a high incidence angle. To compensate for rain-induced backscatter, a simultaneous wind/rain retrieval (SWRR) method, which simultaneously retrieves wind velocity and surface …

Intelligent Scheduling Of Hybrid And Electric Vehicle Storage Capacity In A Parking Lot For Profit Maximization In Grid Power Transactions, Chris Huston, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an intelligent method for scheduling usage of available energy storage capacity from plugin hybrid electric vehicles (PHEV) and electric vehicles (EV). The batteries on these vehicles can either provide power to the grid when parked, known as vehicle- to-grid (V2G) concept or take power from the grid to charge the batteries on the vehicles. A scalable parking lot model is developed with different parameters assigned to fleets of vehicles. The size of the parking lot is assumed to be large enough to accommodate the number of vehicles performing grid transactions. In order to figure out the appropriate …

Nano-Structured Materials For Imaging Polarimetry, Andrew Sarangan

Andrew Sarangan

No abstract provided.

Collision-Tolerant Transmission With Narrow-Beam Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu, Bo Li

Hong-Ning Dai

The application of directional antennas in wireless ad hoc networks brings numerous benefits, such as increased spatial reuse and mitigated interference. Most MAC protocols with directional antennas are based on the RTS/CTS mechanism which works well in wireless ad hoc networks using omni-directional antennas. However, RTS/CTS frames cannot mitigate the interference completely. Besides, they also contribute a lot to the performance overhead. This paper studies the problem from a new perspective. We have found that the transmission success probability under directional transmission and directional reception is quite high when the antenna beamwidth is quite narrow. Motivated by the analytical results, …

Surface Relief D-Fiber Bragg Gratings For Sensing Applications, Tyson Lee Lowder

Theses and Dissertations

This dissertation presents the novel creation of a surface relief fiber Bragg grating on the flat surface of a D-shaped optical fiber. In order to produce an efficient surface relief grating the grating must be etched into the surface of the glass fiber close to the core. A short etch that removes the cladding above the core is performed in order to decrease the core-to-flat distance and allow the light to interact with the grating on the flat surface. Due to the unique D-shape of the optical fiber the mechanical integrity of the fiber remains high even after the fabrication …

Plurality Of Principal Angles For A Given Pseudo-Brewster Angle When Polarized Light Is Reflected At A Dielectric-Conductor Interface, R. M.A. Azzam, A. Alsamman

Electrical Engineering Faculty Publications

The pseudo-Brewster angle ϕpB of minimum reflectance for p-polarized light and the principal angle ϕ¯ at which incident linearly polarized light of the proper azimuth is reflected circularly polarized are considered as functions of the complex relative dielectric function ε of a dielectric–conductor interface over the entire complex ε plane. In particular, the spread of ϕ¯for a given ϕpB is determined, and the maximum difference (ϕ¯−ϕpB)max is obtained as a function of ϕpB . The maximum difference (ϕ¯−ϕpB)max approaches 45° and 0 in the limit as ϕpB→0 and 90°, respectively. ForϕpB<22.666° , multiple principal angles ϕ¯i , i=1,2,3 , appear for each ε in a subdomain of fractional optical constants. …

Cmol/Cmos Hardware Architectures And Performance/Price For Bayesian Memory - The Building Block Of Intelligent Systems, Mazad Shaheriar Zaveri

Dissertations and Theses

The semiconductor/computer industry has been following Moore's law for several decades and has reaped the benefits in speed and density of the resultant scaling. Transistor density has reached almost one billion per chip, and transistor delays are in picoseconds. However, scaling has slowed down, and the semiconductor industry is now facing several challenges. Hybrid CMOS/nano technologies, such as CMOL, are considered as an interim solution to some of the challenges. Another potential architectural solution includes specialized architectures for applications/models in the intelligent computing domain, one aspect of which includes abstract computational models inspired from the neuro/cognitive sciences.

Consequently in this …

Methodology For Developing A Functional Multiscale Architecture Model System Towards Future Integrated Circuits, Yamini Yadov

Dissertations and Theses

Detection of the biochemical species in the environmental pollution, industrial emission monitoring, medical diagnosis, public security, agriculture and a variety of industries has resulted in the emerging need for a generation of high density nanostructured sensor arrays. The fundamental two terminal and three terminal device components because of their potential for specificity eventually have to be integrated into miniaturized and portable nanoarray sensors. One of the key components in these nanosensors is the development of building functional building blocks that improve device performance capabilities. This research is focused on methodology for developing fundamental, functional, multiscale architecture model system for generating …

Request For Graduate Travel Support To Attend The Nanoelectronic Devices For Defense $ Security (Nano-Dds) Conference 2007. To Be Held June 18-21, 2007 In Crystal City Arlington, Carl P. Tripp

University of Maine Office of Research Administration: Grant Reports

Objective:
The objective of this proposal is to request travel funds from NSF to enable graduate students to attend the Nanoelectronic Devices for Defense and Security (NANO-DDS) Conference 2007 to be held on June 18-21, 2007 in Crystal City, Arlington, VA.

Intellectual Merit:
The NANO-DDS conference plans to bridge the intellectual gap between the frontier and application portions of the nanoelectronics deices spectrum for the purpose of accelerating nanotechnology payoffs that have relevance to national Defense and Security in the future. This is a biannual conference. The payoffs are expected to be in the core defense and security related areas …

System And Technique For Retrieving Depth Information About A Surface By Projecting A Composite Image Of Modulated Light Patterns, Laurence G. Hassebrook, Daniel L. Lau, Chun Guan

Electrical and Computer Engineering Faculty Patents

A technique, associated system and program code, for retrieving depth information about at least one surface of an object. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the object; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to …

Non-Destructive Testing Of Physical Characteristics Of Composite Structures, R. Zoughi, Sergey Kharkovsky, Vivian Stephen

Electrical and Computer Engineering Faculty Research & Creative Works

A method for detecting an anomaly in a composite material comprising directing two transmitted electromagnetic wave signals orthogonally polarized with respect to each other from a probe to the composite material, wherein the probe and composite material are positioned for near-field evaluation of the probe. A related apparatus comprising an open-ended square waveguide probe.

Spin Transport Studies In Nanoscale Spin Valves And Magnetic Tunnel Junctions, Sridhar Patibandla

Theses and Dissertations

Spintronics or electronics that utilizes the spin degree of freedom of a single charge carrier (or an ensemble of charge carriers) to store, process, sense or communicate data and information is a rapidly burgeoning field in electronics. In spintronic devices, information is encoded in the spin polarization of a single carrier (or multiple carriers) and the spin(s) of these carrier(s) are manipulated for device operation. This strategy could lead to devices with low power consumption. This dissertation investigates spin transport in one dimensional and two dimensional semiconductors, with a view to applications in spintronic devices.

Design Of An Ic Controller For A Light Emitting Diode Stack, Andrew Alleman

All Theses

An integrated circuit (IC) powering up to nine series connected high brightness light emitting diodes (HBLED's) was designed. The LED's are split into three groups by color (RGB), and the average current through each group is independently varied using a separate microprocessor in conjunction with the IC controller. Integrated comparators compare the voltage across each LED group with internally generated references to check for open or short circuit diodes. In the event of an open circuit failure, the IC controller switches in a SCR to bypass the open circuit device thus maintaining light output at reduced intensity.
Silvaco CAD tools …

Homogeneous Dbd In N2: 1) Lif, Talif And Electrical Measurements, N. Gherardi, Et. Es-Sebbar, C. Sarra-Bourret, N. Naudé, F. Massines

Dr. Et-touhami Es-sebbar

In this paper we compare two different discharges that can be obtained in a DBD configuration, that is to say the filamentary discharge (usual regime in atmospheric DBD) with the Atmospheric Pressure Townsend Discharge (APTD), which is a homogeneous regime obtained in nitrogen atmosphere. The aim is to help in the understanding of the processes which control the transition from one regime to the other. To do so, the discharge is characterized through electrical measurements, coupled with optical diagnostics among which Laser Induced Fluorescence (LIF) for radical density measurements. The influence of the addition of small quantities of additives on …

Optimization Of Top Polymer Gratings To Improve Gan Leds Light Transmission, Xiaomin Jin, Bei Zhang, Tao Dai, Wei Wei, Xiangning Kang, Guoyi Zhang, Simeon Trieu, Fei Wang

Electrical Engineering

We present a grating model of two-dimensional (2D) rigorous coupled wave analysis (RCWA) to study top diffraction gratings on light-emitting diodes (LEDs). We compare the integrated-transmission of the non-grating, rectangular-grating, and triangular-grating cases for the same grating period of 6 μm, and show that the triangular grating has the best performance. For the triangular grating with 6-μm period, the LED achieves the highest light transmission at 6-μm grating bottom width and 2.9-μm grating depth. Compared with the non-grating case, the optimized light transmission improvement is about 74.6%. The simulation agrees with the experimental data of the thin polymer grating encapsulated …

Minimum Mean-Squared Error Estimation Of Mel-Frequency Cepstral Coefficients Using A Novel Distortion Model, Kevin M. Indrebo, Richard J. Povinelli, Michael T. Johnson

Electrical and Computer Engineering Faculty Research and Publications

In this paper, a new method for statistical estimation of Mel-frequency cepstral coefficients (MFCCs) in noisy speech signals is proposed. Previous research has shown that model-based feature domain enhancement of speech signals for use in robust speech recognition can improve recognition accuracy significantly. These methods, which typically work in the log spectral or cepstral domain, must face the high complexity of distortion models caused by the nonlinear interaction of speech and noise in these domains. In this paper, an additive cepstral distortion model (ACDM) is developed, and used with a minimum mean-squared error (MMSE) estimator for recovery of MFCC features …

Chain-Type Wireless Sensor Network For Monitoring Long Range Infrastructures: Architecture And Protocols, Chang Wen Chen, Yu Wang

Electrical Engineering and Computer Science Faculty Publications

We present in this paper an investigation of a special class of wireless sensor networks for monitoring critical infrastructures that may extend for hundreds of miles in distances. Such networks are fundamentally different from traditional sensor networks in that the sensor nodes in this class of networks are deployed along narrowly elongated geographical areas and form a chain-type topology. Based on careful analysis of existing sensor network architectures, we first demonstrate the need to develop new architecture and networking protocols to match the unique topology of chain-type sensor networks. We then propose hierarchical network architecture that consists of clusters of …

Canonical Correlation Feature Selection For Sensors With Overlapping Bands: Theory And Application, Biliana S. Paskaleva, Majeed M. Hayat, Zhipeng Wang, J. Scott Tyo, Sanjay Krishna

Electrical and Computer Engineering Faculty Research and Publications

The main focus of this paper is a rigorous development and validation of a novel canonical correlation feature- selection (CCFS) algorithm that is particularly well suited for spectral sensors with overlapping and noisy bands. The proposed approach combines a generalized canonical correlation analysis framework and a minimum mean-square-error criterion for the selection of feature subspaces. The latter induces ranking of the best linear combinations of the noisy overlapping bands and, in doing so, guarantees a minimal generalized distance between the centers of classes and their respective reconstructions in the space spanned by sensor bands. To demonstrate the efficacy and the …

Optimisation Of Multicast Routing In Wireless Mesh Networks, Brian Keegan, Karol Kowalik, Mark Davis

Conference papers

In recent years Wireless Mesh Networks have been deployed and grown in popularity in many metropolitan areas. The deployment of such networks has allowed clients to gain access to publicly available broadband networks. The implementation of wireless mesh networks requires that backhaul services (traditionally carried by wired networks) be maintained via wireless mesh points. Because of their structure, wireless mesh networks provide an excellent means for targeting a large group of end users or simply to relay data. This may be achieved by means of broadcasting or more specifically multicasting. The lack of standards and support for multicasting over wireless …

Investigation Of Across-Layer Modification To The Dsr Routing Protocol In Wireless Mesh Networks, Mustafa Ramadhan, Mark Davis

Conference papers

This work introduces a cross-layer modification to the DSR protocol that increases the global throughput in wireless mesh networks. In our modified DSR protocol we have introduced the Access Efficiency metric as an alternative to the hop-count metric in order to improve the route selection mechanism. The selected path in the route selection mechanism is identified by choosing the path with the highest minimum Access Efficiency value. We have employed the OPNET modeller as a simulator to examine two different patterns of traffic for a series of randomly generated network topologies. Each topology was simulated twice. One simulation used the …

Effects Of Lline Rate On Vvideo Qos Over Wireless Networks: An Experimental Approach, Stuart Wallace, Mark Davis

Conference papers

Video streaming over Wireless Local Area Networks (WLANS) is becoming an increasingly popular service. However, end user OoS is highly influenced by many factors. These include the video codec used, the packetization scheme, error concealment and correction techniques, the complexity of the video, propagation losses, and the line rate. In this paper the effect of the line rate on the capacity of the network when streaming multimedia content is analyzed experimentally. It is shown that as the line rate decreases the bandwidth load of the video stream dramatically increases leading to poor QoS at the client side. As automatic line …

An Investigation Of The Correlation Between Passive Monitoring And Activie Probing Techniques Used In Wlan Mesh Networks, Chenzhe Zhang, Mark Davis

Conference papers

In recent years, Wireless Mesh Networks (WMNs) have emerged as a promising solution to provide low cost networks that extend Internet access and other networking services. Mesh routers form the backbone connectivity through cooperative routing in an often unstable wireless medium. Therefore, the techniques used to monitor and manage the performance metrics to help optimize the link performance in WMNs. This paper presents an assessment of the correlation between passive monitoring and active probing techniques used for link performance measurement in WMNs. This paper presents an assessment of the correlation between passive monitoring and active probing techniques used for link …

Temperature (5.6-300k) Dependence Comparison Of Carrier Transport Mechanisms In Hfo2/Sio2 And Sio2 Mos Gate Stacks, Richard G. Southwick Iii, Justin Reed, Christopher Buu, Hieu Bui, Ross Butler, G. Bersuker, William B. Knowlton

Electrical and Computer Engineering Faculty Publications and Presentations

Temperature dependent measurements have been used to examine transport mechanisms and energy band structure in MOS devices. In this study, a comparison between high-k HfO₂ dielectrics and conventional SiO₂ dielectrics is made to investigate dielectric specific thermally activated mechanisms. Temperature dependent measurements on large area n/pMOSFETs composed of SiO₂ and HfO₂/SiO₂ gate dielectrics were performed from 5.6 K to 300 K. A large increase in the gate leakage current is observed at the formation of the minority carrier channel. The data indicate that gate leakage current prior to the formation of the minority channel …

Imaging Of Buried Utilities By Ultra Wideband Sensory Systems, Arun Prakash Jaganathan

Doctoral Dissertations

Third-party damage to the buried infrastructure like natural gas pipelines, water distribution pipelines and fiber optic cables are estimated at $10 billion annually across the US. Also, the needed investment in upgrading our water and wastewater infrastructure over the next 20 years is estimated by Environmental Protection Agency (EPA) at $400 billion, however, non-destructive condition assessment technologies capable of providing quantifiable data regarding the structural integrity of our buried assets in a cost-effective manner are lacking. Both of these areas were recently identified several U.S. federal agencies as 'critical national need'. In this research ultra wideband (UWB) time-domain radar technology …

A Detailed Look At The Omega-K Algorithm For Processing Synthetic Aperture Radar Data, Matthew A. Tolman

Theses and Dissertations

In this thesis, the Omega-k algorithm used for processing stripmap synthetic aperture radar (SAR) data is explored in detail. While the original Omega-k algorithm does not achieve the same SNR as a matched filter, a modification is presented which enables the algorithm to nearly achieve that SNR. It is shown that the focused point spread function obtained when the Omega-k algorithm is used differs in important ways from the output of a modified version of the matched filter. Spread out sidelobes and a stretched mainlobe are observed when the data is processed by the Omega-k algorithm. These differences may increase …

Hardware Implementation Of An Ais-Based Optimal Excitation Controller For An Electric Ship, Chuan Yan, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

The operation of high energy loads on Navy's future electric ships, such as directed energy weapons, will cause disturbances in the main bus voltage and impact the operation of the rest of the power system when the pulsed loads are directly powered from the main dc bus. This paper describes an online design and laboratory hardware implementation of an optimal excitation controller using an artificial immune system (AIS) based algorithm. The AIS algorithm, a clonal selection algorithm (CSA), is used to minimize the effects of pulsed loads by improved excitation control and thus, reduce the requirement on energy storage device …

Real-Time Implementation Of Intelligent Modeling And Control Techniques On A Plc Platform, Curtis Alan Parrott, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

Programmable logic controllers (PLCs) have been used for many decades for standard control in industrial and factory environments. Over the years, PLCs have become computational efficient and powerful, and a robust platform with applications beyond the standard control and factory automation. Due to the new advanced PLC's features and computational power, they are ideal platforms for exploring advanced modeling and control methods, including computational intelligence based techniques such as neural networks, particle swarm optimization (PSO) and many others. Some of these techniques require fast floating-point calculations that are now possible in real-time on the PLC. This paper focuses on the …