Engineering Commons^™

Exploiting Multiple Sensory Modalities In Brain-Machine Interfaces, Aaron J. Suminski, Dennis C. Tkach, Nicholas G. Hatsopoulos

Biomedical Engineering Faculty Research and Publications

Recent improvements in cortically-controlled brain-machine interfaces (BMIs) have raised hopes that such technologies may improve the quality of life of severely motor-disabled patients. However, current generation BMIs do not perform up to their potential due to the neglect of the full range of sensory feedback in their strategies for training and control. Here we confirm that neurons in the primary motor cortex (MI) encode sensory information and demonstrate a significant heterogeneity in their responses with respect to the type of sensory modality available to the subject about a reaching task. We further show using mutual information and directional tuning analyses …

A Framework For Bioacoustic Vocalization Analysis Using Hidden Markov Models, Yao Ren, Michael T. Johnson, Patrick J. Clemins, Michael Darre, Sharon Stuart Glaeser, Tomasz S. Osiejuk, Ebenezer Out-Nyarko

Electrical and Computer Engineering Faculty Research and Publications

Using Hidden Markov Models (HMMs) as a recognition framework for automatic classification of animal vocalizations has a number of benefits, including the ability to handle duration variability through nonlinear time alignment, the ability to incorporate complex language or recognition constraints, and easy extendibility to continuous recognition and detection domains. In this work, we apply HMMs to several different species and bioacoustic tasks using generalized spectral features that can be easily adjusted across species and HMM network topologies suited to each task. This experimental work includes a simple call type classification task using one HMM per vocalization for repertoire analysis of …

Analysis And Diagnostics Of Adjacent And Nonadjacent Broken-Rotor-Bar Faults In Squirrel-Cage Induction Machines, Gennadi Y. Sizov, Ahmed Mohamed Sayed Ahmed, Chia-Chou Yeh, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

In this paper, faults associated with the rotor of an induction machine are considered. More specifically, effects of adjacent and nonadjacent bar breakages on rotor fault diagnostics in squirrel-cage induction machines are studied. It is shown that some nonadjacent bar breakages may result in the masking of the commonly used fault indices and, hence, may lead to a possible misdiagnosis of the machine. A discussion of the possible scenarios of these breakages as well as some conclusions regarding the types of squirrel-cage induction machines (number of poles, number of squirrel-cage bars, etc.) that may be more prone to these nonadjacent …

Evaluation Of Alternatives For Florida's 2010 Energy Code Update For Residential Buildings, Florida Solar Energy Center, Philip W. Fairey

FSEC Energy Research Center®

This report provides results of analysis of the Florida Energy Code (FEC) with respect to requirements of Florida House Bill 7135. The analysis uses Florida's performance-based code compliance software, EnergyGauge® USA, to conduct detailed analysis of H.B 7135 requirements to significantly increase the efficiency of new homes over time. First, results of an analysis of the long-term, year 2019 requirement for a 50% increase in new home energy efficiency are presented. Next, the 2009 edition of the International Energy Conservation Code (IECC) is analyzed with respect to the H.B. 7135 dual requirements that the 2009 IECC become the foundation code …

Steel Sheet Sheathing Options For Cold-Formed Steel Framed Shear Wall Assemblies Providing Shear Resistance - Phase 2, Cheng Yu, Yujie Chen

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The North American Standard for Cold-Formed Steel Framing - Lateral Design, AISI S213-07, provides design provisions for cold-formed steel framed shear walls with steel sheet sheathing. However, options are limited to 18-mil and 27-mil steel sheet sheathing. Phase 1 of this project was successfully completed and a final report, Steel Sheet Sheathing Options for Cold-Formed Steel Framed Shear Wall Assemblies Providing Shear Resistance, dated October 31, 2007 has been issued. The primary objective of Phase 1 was to add values to AISI S213 for 30-mil and 33-mil sheet steel shear walls with 2:1 and 4:1 aspect ratios and 6”, 4”, …

Terrain Constrained Stereo Correspondence, Gabrielle Inglis, Chris Roman

Graduate School of Oceanography Faculty Publications

There is a persistent need in the oceanographic community for accurate three dimensional reconstructions of seafloor structures. To meet this need underwater mapping techniques have expanded to include the use of stereo vision and high frequency multibeam sonar for mapping scenes 10's to 100's of square meters in size. Both techniques have relative advantages and disadvantages that depend on the task at hand and the desired accuracy. In this paper, we develop a method to constrain the often problematic stereo correspondence search to small sections of the image that correspond to estimated ranges along the epipolar lines calculated from coregistered …

Modeling Soil Depth From Topographic And Land Cover Attributes, Teklu K. Tesfa, David G. Tarboton, David G. Chandler, James P. Mcnamara

Civil and Environmental Engineering Faculty Publications

Soil depth is an important input parameter in hydrological and ecological modeling. Presently, the soil depth data available in national soil databases (STATSGO and SSURGO) from the Natural Resources Conservation Service are provided as averages within generalized land units (map units). Spatial uncertainty within these units limits their applicability for distributed modeling in complex terrain. This work reports statistical models for prediction of soil depth in a semiarid mountainous watershed that are based upon the relationship between soil depth and topographic and land cover attributes. Soil depth was surveyed by driving a rod into the ground until refusal at locations …

A Pll-Based Multirate Structure For Time-Varying Power Systems Harmonic/ Interharmonic Estimation, Janison Rodrigues De Carvalho, Carlos A. Duque, Moisés V. Ribeiro, Augusto S. Cerqueira

University Faculty Publications and Creative Works

This paper describes a phase-locked-loop (PLL)-based power systems harmonic estimation algorithm, which uses an analysis filter bank and multirate processing. The filter bank is composed of bandpass filters. The initial center frequency of each filter is purposely chosen to be equal to harmonic frequencies. However, an adaptation strategy makes it possible to track time-varying frequencies as well as interharmonic components. A downsampler device follows the filtering stage, reducing the computational burden, especially because undersampling operations are performed. Finally, the last stage is composed of a PLL estimator which provides estimates for amplitude, phase, and frequency of the input signal. The …

A Pll-Based Multirate Structure For Time-Varying Power Systems Harmonic/ Interharmonic Estimation, Janison Rodrigues De Carvalho, Carlos A. Duque, Moisés V. Ribeiro, Augusto S. Cerqueira

University Faculty Publications and Creative Works

This paper describes a phase-locked-loop (PLL)-based power systems harmonic estimation algorithm, which uses an analysis filter bank and multirate processing. The filter bank is composed of bandpass filters. The initial center frequency of each filter is purposely chosen to be equal to harmonic frequencies. However, an adaptation strategy makes it possible to track time-varying frequencies as well as interharmonic components. A downsampler device follows the filtering stage, reducing the computational burden, especially because undersampling operations are performed. Finally, the last stage is composed of a PLL estimator which provides estimates for amplitude, phase, and frequency of the input signal. The …

Mechanical Behavior And Length Adaptation Of Rabbit Bladder Smooth Muscle, Atheer Almasri

Theses and Dissertations

Overactive bladder (OAB), involuntary contractions during bladder filling, is a common condition affecting 17% of the adult population worldwide, and in the U.S. ranks ahead of diabetes in a list of the 10 most common chronic disorders (Mullins 2009). Mechanical mechanisms contributing to OAB are not completely understood and because of the unique function and broad volume range of the bladder, there may be mechanical characteristics that distinguish detrusor smooth muscle (DSM) in bladder from other smooth muscles. Recent studies have shown that the length-passive tension curve in DSM exhibits adjustable passive stiffness (APS) characterized by a passive curve that …

Stimulus Reconstruction From The Biphasic Integrate-And-Fire Sampler, Alexander Singh Alvarado, José C. Príncipe, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

An algorithm to recover the encoded stimulus from a biphasic integrate-and-fire model has been proposed using the sampling framework for local averages. The algorithm converges for sparse sampling sets, common in extracellular neural recordings. Moreover, the spike region can be recovered with up to 50 dB accuracy even though the instantaneous and overall pulse rates are below the Nyquist bound. ©2009 IEEE.

Differential Eeg, Sheng Feng Yen, Daniel Schoonover, Justin C. Sanchez, Jose C. Principe, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

We propose to improve the spatial resolution of electroencephalography (EEG) using a differential recording methodology. Conventional EEG (CEEG) systems independently amplify and digitize the signal from each electrode. The Differential EEG (DEEG) approach amplifies the minute difference signal between neighboring electrodes which greatly eases the burden on the subsequent amplification and data conversion stages. A custom DEEG system was designed and fabricated in a 0.6 um CMOS process. The fabricated chip was built into a small prototype DEEG recording system used to measure alpha waves from the occipital lobe of a human subject. We show that the differential approach suffers …

An Integrated Recording System Using An Asynchronous Pulse Representation, Sheng Feng Yen, Jie Xu, Manu Rastogi, John G. Harris, Jose C. Principe, Justin C. Sanchez

Electrical and Computer Engineering Faculty Research & Creative Works

A neuronal recording system for brain-machine interfaces (BMI) based on asynchronous biphasic pulse coding is described. It demonstrates the first step in the development of a complete implanted wireless solution with fully integrated circuit architecture. A recording experiment comparing in parallel a commercial recording system (Tucker-Davis Technology (TDT)) and the UF's custom solution (FWIRE) is set up to compare performance. The novel aspect of the UF system is that the analog signal is represented by an asynchronous pulse train, which provides a low-power, low-bandwidth, noise-resistant means for coding and transmission. Taking advantage of neural firing features, the pulse-based approach uses …

Use Of In-Planta Solid Phase Sampling Devices To Delineate Voc Plumes, Joel Gerard Burken, Kendra Waltermire, Emily Sheehan

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Plants Directly Interact with Surrounding Water, Air, and Soil, Collecting and Storing Chemicals and Elements from the Surrounding Environment. Two New and Innovative Sampling Methods in Which This Valuable Data Can Be Accessed to Replace as Well as Supplement Contaminated-Site Investigations Have Been Developed. When Determining the Extent of the Plume on a Contaminated Site, Groundwater Sampling May Be Limited Due to Time, Site Access, and Expense. by using New Techniques that Place Sampling Devices Inside the Trees on Site, We Can Sample Trees Naturally Occurring on a Contaminated Site or Those Planted in Phytoremediation or Redevelopment Efforts, Evaluate the …

3d Reconstruction And Visualization Of A Hovering Dragonfly, Christopher Koehler, Thomas Wischgoll, Haibo Dong, Zachary Gaston, Hui Wan

Computer Science and Engineering Faculty Publications

No abstract provided.

Periodicity Detection And Localization Using Spike Timing From The Aer Ear, Theodore Yu, Andrew Schwartz, John Harris, Malcolm Slaney, Shih Chii Liu

Electrical and Computer Engineering Faculty Research & Creative Works

We present a system consisting of a spiking cochlea chip and real-time event-based processing software that is able to discriminate between two sets of sounds based on their periodicity content. The periodicity measurements are computed from the spike timing information of asynchronous output spikes from the binaural spiking-cochlea chip. The chip consists of a matched pair of silicon cochlea with an address event interface for the output. Each section of the cochlea is modeled by a second-order low-pass filter followed by a simplified Inner Hair Cell circuit and a Spiking Neuron circuit. We show discrimination results using the periodicity measure …

A Low-Complexity Hardware Implementation Of Discrete-Time Frequency-Selective Rayleigh Fading Channels, Fei Ren, Yahong R. Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

A low-complexity hardware implementation method is proposed for discrete-time frequency-selective Rayleigh fading channels. the proposed method first employs the Sum-of-Sinusoids method to generate multiple independent flat fading channel responses, then utilizes a simple weight-delay-sum filtering method to incorporate the fractionally delayed multipath rays into inter-tap correlated tap gains. It thus achieves accurate correlation properties in both inter-tap correlation and temporal correlation (or Doppler spectrum). the proposed method is implemented by an Altera Stratix II FPGA development kit and the results show excellent performance match with those by MATLAB software simulations. ©2009 IEEE.

Simulations Of Aquaculture Dissolved Waste Transport And Mixing In Near-Coastal Waters, S. K. Venayagamoorthy, O. B. Fringer, J. R. Koseff, R. L. Naylor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The present study focuses on understanding the transport and fate of dissolved waste from aquaculture pens in near-coastal environments using the hydrodynamic code SUNTANS, which employs unstructured grids to compute flows at very high resolution. We perform simulations of the dissolved waste field and study the effects of different flow conditions (tides and currents) on the evolution of the waste plume. The fish pen causes partial blockage of the flow, leading to the deceleration of the approaching flow and the formation of a downstream wake. Results of the concentration field for an oscillatory flow condition superimposed on a mean current …

A New Variable Step-Size Fractional Lower-Order Moment Algorithm For Non-Gaussian Interference Environments, Tiange Shao, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

A new variable step-size fractional lower-order moment (FLOM) algorithm is proposed for non-Gaussian interference suppression. the Normalized FLOM algorithm is a generalization of the normalized least mean square (NLMS) algorithm with a lower order p ≤ 2 and p = 2 corresponding to the NLMS algorithm. with a fixed step size, the smaller the order p, the faster the convergence of the NFLOM algorithm, but the higher the excess mean square errors (MSE) after convergence. the proposed vs.S-FLOM provides a compromise solution to the two conflicting goals of low excess MSE and fast convergence. Simulation results for a system identification …

Biologically Plausible Speech Recognition Using Spike-Based Phase Locking Cues, Ismail Uysal, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A biologically plausible algorithm is proposed for phoneme recognition that makes use of spikes for computation. The prototype system is demonstrated on voiced phonemes and shows competitive performance with state-of-the-art systems on a vowel dataset in the presence of noise. Using novel phase locking cues, the algorithm performs surprisingly well down to SNR values as low as 5dB, where the performance of the baseline algorithm used for comparison drops considerably. These results suggest, not only a possible explanation for the extreme noise robustness of human recognition, but also a novel technique for information processing for speech signals with computers. ©2009 …

Low Power Integrate And Fire Circuit For Data Conversion, Manu Rastogi, Vaibhav Garg, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

We have developed an adaptively biased Integrate and Fire (I&F) circuit to reduce the power consumption of our ADC replacement approach. Unlike conventional circuits this I&F consumes no standby power. Power consumed is input signal dependent and increases exponentially as the input approaches the set threshold value. We describe the circuit model and present an intuitive as well as mathematical model for the power savings. Results from the chip fabricated in AMI 0.6 μm technology are also presented. ©2009 IEEE.

A Biphasic Integrate-And-Fire System, Sheng Feng Yen, Jie Xu, Manu Rastogi, John G. Harris, Jose C. Principe, Justin C. Sanchez

Electrical and Computer Engineering Faculty Research & Creative Works

A neuronal recording system for brain-machine interfaces (BMI) based on asynchronous biphasic pulse coding is described. It demonstrates the first step in the development of a completely implanted wireless solution with a fully integrated circuit architecture. A recording experiment comparing, in parallel, a commercial recording system (Tucker-Davis Technology (TDT)) and the UF's custom solution (FWIRE) is set up to compare performance. The novel aspect of the UF system is that the analog signal is represented by an asynchronous pulse train, which provides a low-power, low-bandwidth, noise resistant means for coding and transmission. Taking advantage of neural firing features, the pulse-based …

Observation Of Quantum-Hall Effect In Gated Epitaxial Graphene Grown On Sic (0001), T Shen, J J. Gu, M Xu, Michael Bolen, Michael A. Capano, L Engel, P. D. Ye

Birck and NCN Publications

Epitaxial graphene films examined were formed on the Si-face of semi-insulating 4H-SiC substrates by a high temperature sublimation process. A high-k gate stack on the epitaxial graphene was realized by inserting a fully oxidized nanometer thin aluminum film as a seeding layer, followed by an atomic-layer deposition process. The electrical properties of epitaxial graphene films are retained after gate stack formation without significant degradation. At low temperatures, the quantum-Hall effect in Hall resistance is observed along with pronounced Shubnikov-de Haas oscillations in diagonal magnetoresistance of gated epitaxial graphene on SiC (0001).

In-Plane All-Photonic Transduction With Differential Splitter Using Double-Step Rib Waveguide For Photonic Microcantilever Arrays, Ryan Anderson, Seunghyun Kim, Gregory P. Nordin, Jong Wook Noh, Weisheng Hu

Faculty Publications

We report a differential splitter consisting of an asymmetric double-step multimode rib waveguide and a Y-branch splitter for in-plane photonic transduction of photonic microcantilever deflection. Arrays of photonic microcantilevers are integrated with differential splitters and an optical waveguide network to demonstrate uniformity and sensitivity of transduction. Measurement results from multiple arrays indicate a sensitivity of 0.32 x 10-3 nm-1 and minimum detectable deflection of 141 pm for a 3.5 Hz measurement bandwidth.

Agenda: World Energy Justice Conference And Appropriate Technology Arcade, University Of Colorado Boulder. Center For Energy & Environmental Security, University Of Colorado Boulder. School Of Law

World Energy Justice Conference (October 23-24)

The 2009 CEES Energy Justice Conference took place at the University of Colorado Law School on October 23rd and 24th, 2009. It featured 11 sessions, more than 40 speakers, and attracted over 200 attendees. The Conference brought together leading international and U.S. decision-makers in politics, engineering, public health, law, business, economics, and innovators in the sciences to explore how best to address the critical needs of the energy-oppressed poor (EOP) through long-term interdisciplinary action, information sharing, and deployment of appropriate sustainable energy technologies (ASETs).

The Colorado Journal of International Environmental Law & Policy (CJIELP) at the University of Colorado Law …

On The Thermal Activation Of Negative Bias Temperature Instability, Richard G. Southwick Iii, William B. Knowlton, Ben Kaczer, Tibor Grasser

Materials Science and Engineering Faculty Publications and Presentations

The temperature dependence of negative bias temperature instability (NBTI) is investigated on 2.0nm SiO₂ devices from temperatures ranging from 300K down to 6K with a measurement window of ~12ms to 100s. Results indicate that classic NBTI degradation is observed down to ~200K and rarely observed at temperatures below 140K in the experimental window. Since experimental results show the charge trapping component contributing to NBTI is thermally activated, the results cannot be explained with the conventionally employed elastic tunneling theory. A new mechanism is observed at temperatures below 200K where device performance during stress conditions improves rather than degrades with …

Fabrication Of High-Capacity Biomolecular Carriers From Dispersible Single-Walled Carbon Nanotube-Polymer Composites, Pu Zhang, David B. Henthorn

Chemical and Biochemical Engineering Faculty Research & Creative Works

One of the most interesting applications for carbon nanotubes is as a support material for bioanalytical devices. in this work, we successfully used an ultraviolet light initiated "graft from" polymerization method to fabricate polymer functionalized carbon nanotubes (PFCNTs) with pendant chains of various functionalities, including poly (ethylene glycol) chains to boost dispersibility and pendant epoxy groups for protein conjugate sites. a model enzyme, alkaline phosphatase, was used to study biomolecule loading efficiency as well as the retention of enzyme activity. Samples with various ratios of the two monomers were fabricated to optimize their use in aqueous environments, and an optimal …

Methods And Devices For Cryopreservation Of Biological Cells And Tissues, Dayong Gao, Gary Van Zant, Xiangdong Cui

Mechanical Engineering Faculty Patents

Novel methods, compositions, and devices for achieving optimal cooling of living cells during cryopreservation are disclosed. In one aspect, the method comprises gradually cooling the cell to a first predetermined temperature, followed by rapidly cooling the cell to a second predetermined temperature. In another aspect, a device is described for achieving a desired cooling rate for a cell, comprising a first container for holding a cell, a second container for holding the first container, and optionally a frame for holding the first container in a spaced apart relationship with the second container. The method of the invention comprises placing cells …

An Overview Of The Odot Safety Investigations Manual, Christopher M. Monsere, Karen Dixon

Civil and Environmental Engineering Faculty Publications and Presentations

This presentation provides an overview of the ODOT Safety Investigations Manual. The objective of this manual is to function as a resource that will assist ODOT traffic investigators with highway safety project screening and evaluations.

East Bay Energy Consortium Budget Committee Meeting Minutes, October 19, 2009, East Bay Energy Consortium

East Bay Energy Consortium Meeting Minutes

No abstract provided.