Engineering Commons^™

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 …

Demonstration Of A Bias Tunable Quantum Dots-In-A-Well Focal Plane Array, Jonathan Andrews, Woo-Yong Jang, Jorge E. Pezoa, Yagya D. Sharma, Sang Jun Lee, Sam Kyu Noh, Majeed M. Hayat, Sergio Restaino, Scott W. Teare, Sanjay Krishna

Electrical and Computer Engineering Faculty Research and Publications

Infrared detectors based on quantum wells and quantum dots have attracted a lot of attention in the past few years. Our previous research has reported on the development of the first generation of quantum dots-in-a-well (DWELL) focal plane arrays, which are based on InAs quantum dots embedded in an InGaAs well having GaAs barriers. This focal plane array has successfully generated a two-color imagery in the mid-wave infrared (i.e. 3–5 μm) and the long-wave infrared (i.e. 8–12 μm) at a fixed bias voltage. Recently, the DWELL device has been further modified by embedding InAs quantum dots in InGaAs …

On Coupling A Lumped Parameter Heart Model And A Three-Dimensional Finite Element Aorta Model, H. J. Kim, Irene E. Vignon-Clementel, C. A. Figueroa, John F. Ladisa, K. E. Jansen, Jeffrey A. Feinstein, Charles A. Taylor

Biomedical Engineering Faculty Research and Publications

Aortic flow and pressure result from the interactions between the heart and arterial system. In this work, we considered these interactions by utilizing a lumped parameter heart model as an inflow boundary condition for three-dimensional finite element simulations of aortic blood flow and vessel wall dynamics. The ventricular pressure–volume behavior of the lumped parameter heart model is approximated using a time varying elastance function scaled from a normalized elastance function. When the aortic valve is open, the coupled multidomain method is used to strongly couple the lumped parameter heart model and three-dimensional arterial models and compute ventricular volume, ventricular pressure, …

Comparison Of Cumulative Planimetry Versus Manual Dissection To Assess Experimental Infarct Size In Isolated Hearts, Matthias L. Riess, Samhita S. Rhodes, David F. Stowe, Mohammed Aldakkak, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

Introduction

Infarct size (IS) is an important variable to estimate cardiac ischemia/reperfusion injury in animal models. Triphenyltetrazolium chloride (TTC) stains viable cells red while leaving infarcted cells unstained. To quantify IS, infarcted and non-infarcted tissue is often manually dissected and weighed (IS-DW). An alternative is to measure infarcted areas by cumulative planimetry (IS-CP).

Methods

We prospectively compared these two methods in 141 Langendorff-prepared guinea pig hearts (1.44 ± 0.02 g) that were part of different studies on mechanisms of cardioprotection. Hearts were perfused with Krebs–Ringer's and subjected to 30 min global ischemia after various cardioprotective treatments. Two hours after reperfusion …

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 …

Highway Work Zone Risk Factors And Their Impact On Crash Severity, Yingfeng Li, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

Numerous factors may contribute to high-severity crashes in highway work zones. Identifying these factors and then alleviating their impact is a challenging task that traffic engineers and researchers have to confront. In this study, the work zone risk factors that could increase the probability of causing fatalities when severe crashes occur were examined using a comprehensive approach. The researchers first identified the significant risk factors based on a screening process that incorporates both statistical analyses and empirical research findings. They then systematically investigated these factors using logistic regression and frequency analysis techniques. The severe crashes including the fatal crashes between …

Splenic Trauma As An Adverse Effect Of Torso-Protecting Side Airbags: Biomechanical And Case Evidence, Jason John Hallman, Karen J. Brasel, Narayan Yoganandan, Frank A. Pintar

Biomedical Engineering Faculty Research and Publications

Injury mechanisms from frontal airbags, first identified in anecdotal reports, are now well documented for pediatric, small female, and out-of-position occupants. In contrast, torso side airbags have not yet been consistently associated with specific injury risks in field assessments. To determine possible torso side airbag-related injuries, the present study identified crashes involving side airbags from reports within the CIREN, NASS, and SCI databases. Injury patterns were compared to patterns from lateral crashes in absence of side airbag. Splenic trauma (AIS 3+) was found present in five cases of torso side airbag deployment at lower impact severity (as measured by velocity …

Modulation Of Mitochondrial Bioenergetics In The Isolated Guinea Pig Beating Heart By Potassium And Lidocaine Cardioplegia: Implications For Cardioprotection, Mohammed Aldakkak, David F. Stowe, Edward J. Lesnefsky, James S. Heisner, Qun Chen, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

Mitochondria are damaged by cardiac ischemia/reperfusion (I/R) injury but can contribute to cardioprotection. We tested if hyperkalemic cardioplegia (CP) and lidocaine (LID) differently modulate mitochondrial (m) bioenergetics and protect hearts against I/R injury. Guinea pig hearts (n = 71) were perfused with Krebs Ringer's solution before perfusion for 1 minute just before ischemia with either CP (16 mM K+) or LID (1 mM) or Krebs Ringer's (control, 4 mM K+). The 1-minute perfusion period assured treatment during ischemia but not on reperfusion. Cardiac function, NADH, FAD, m[Ca2+], and superoxide (reactive oxygen species) were assessed at baseline, during the 1-minute perfusion, …

Flexor Reflex Decreases During Sympathetic Stimulation In Chronic Human Spinal Cord Injury, Mark Kevin Garrison, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

A better understanding of autonomic influence on motor reflex pathways in spinal cord injury is important to the clinical management of autonomic dysreflexia and spasticity in spinal cord injured patients. The purpose of this study was to examine the modulation of flexor reflex windup during episodes of induced sympathetic activity in chronic human spinal cord injury (SCI). We simultaneously measured peripheral vascular conductance and the windup of the flexor reflex in response to conditioning stimuli of electrocutaneous stimulation to the opposite leg and bladder percussion. Flexor reflexes were quantified using torque measurements of the response to a noxious electrical stimulus …

Bit Error Rates For Ultrafast Apd Based Optical Receivers: Exact And Large Deviation Based Asymptotic Approaches, Peng Sun, Majeed M. Hayat, Abhik K. Das

Electrical and Computer Engineering Faculty Research and Publications

Exact analysis as well as asymptotic analysis, based on large-deviation theory (LDT), are developed to compute the bit-error rate (BER) for ultrafast avalanche-photodiode (APD) based optical receivers assuming on-off keying and direct detection. The effects of intersymbol interference (ISI), resulting from the APD's stochastic avalanche buildup time, as well as the APD's dead space are both included in the analysis. ISI becomes a limiting factor as the transmission rate approaches the detector's bandwidth, in which case the bit duration becomes comparable to APD's avalanche buildup time. Further, the effect of dead space becomes significant in high-speed APDs that employ thin …

Optimization Of Inp Apds For High-Speed Lightwave Systems, Daniel S.G. Ong, Jo Shien Ng, Majeed M. Hayat, John P.R. David

Electrical and Computer Engineering Faculty Research and Publications

Calculations based on a rigorous analytical model are carried out to optimize the width of the indium phosphide avalanche region in high-speed direct-detection avalanche photodiode-based optical receivers. The model includes the effects of intersymbol interference (ISI), tunneling current, avalanche noise, and its correlation with the stochastic avalanche duration, as well as dead space. A minimum receiver sensitivity of -28 dBm is predicted at an optimal width of 0.18 mum and an optimal gain of approximately 13, for a 10 Gb/s communication system, assuming a Johnson noise level of 629 noise electrons per bit. The interplay among the factors controlling the …

Efficient Embedded Speech Recognition For Very Large Vocabulary Mandarin Car-Navigation Systems, Yanmin Qian, Jia Liu, Michael T. Johnson

Electrical and Computer Engineering Faculty Research and Publications

Automatic speech recognition (ASR) for a very large vocabulary of isolated words is a difficult task on a resource-limited embedded device. This paper presents a novel fast decoding algorithm for a Mandarin speech recognition system which can simultaneously process hundreds of thousands of items and maintain high recognition accuracy. The proposed algorithm constructs a semi-tree search network based on Mandarin pronunciation rules, to avoid duplicate syllable matching and save redundant memory. Based on a two-stage fixed-width beam-search baseline system, the algorithm employs a variable beam-width pruning strategy and a frame-synchronous word-level pruning strategy to significantly reduce recognition time. This algorithm …

Discriminating Pulmonary Hypertension Caused By Monocrotaline Toxicity From Chronic Hypoxia By Near-Infrared Spectroscopy And Multivariate Methods Of Analysis, Simon Duri, Robert C. Molthen, Chieu D. Tran

Biomedical Engineering Faculty Research and Publications

A new method has been developed for the determination of tissue pathology caused by chronic hypoxia and monocrotaline toxicity. The method is based on the use of near-infrared (NIR) spectrophotometry to measure spectra of lung tissue from normal chronic hypoxia (CH) and monocrotaline (MCT) models of pulmonary hypertension (PH), followed by analysis using multivariate methods, that is, principal component analysis (PCA) and partial least squares (PLS). Synergistic use of NIR with the PCA/PLS method makes it possible, for the first time, not only to divide different lung tissue samples into their respective groups (normal, CH, and MCT) but also to …

Optimal "Image-Based" Weighting For Energy-Resolved Ct, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

This paper investigates a method of reconstructing images from energy-resolved CT data with negligible beam-hardening artifacts and improved contrast-to-nosie [sic] ratio (CNR) compared to conventional energy-weighting methods. Conceptually, the investigated method first reconstructs separate images from each energy bin. The final image is a linear combination of the energy-bin images, with the weights chosen to maximize the CNR in the final image. The optimal weight of a particular energy-bin image is derived to be proportional to the contrast-to-noise-variance ratio in that image. The investigated weighting method is referred to as “image-based” weighting, although, as will be described, the weights can …

Elastic, Viscous, And Mass Load Effects On Poststroke Muscle Recruitment And Co-Contraction During Reaching: A Pilot Study, Tina M. Stoeckmann, Katherine J. Sullivan, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Background: Resistive exercise after stroke can improve strength (force-generating capacity) without increasing spasticity (velocity-dependent hypertonicity). However, the effect of resistive load type on muscle activation and co-contraction after stroke is not clear.

Objective: The purpose of this study was to determine the effect of load type (elastic, viscous, or mass) on muscle activation and co-contraction during resisted forward reaching in the paretic and nonparetic arms after stroke.

Design: This investigation was a single-session, mixed repeated-measures pilot study.

Methods: Twenty participants (10 with hemiplegia and 10 without neurologic involvement) reached forward with each arm against equivalent elastic, viscous, and mass loads. …

Demonstration Of Bias-Controlled Algorithmic Tuning Of Quantum Dots In A Well (Dwell) Midir Detectors, Woo-Yong Jang, Majeed M. Hayat, J. Scott Tyo, Ram S. Attaluri, Thomas E. Vandervelde, Yagya D. Sharma, Rajeev Shenoi, Andreas Stintz, Elizabeth R. Cantwell, Steven C. Bender, Sang Jun Lee, Sam Kyu Noh, Sanjay Krishna

Electrical and Computer Engineering Faculty Research and Publications

The quantum-confined Stark effect in intersublevel transitions present in quantum-dots-in-a-well (DWELL) detectors gives rise to a midIR spectral response that is dependent upon the detector's operational bias. The spectral responses resulting from different biases exhibit spectral shifts, albeit with significant spectral overlap. A postprocessing algorithm was developed by Sakoglu that exploited this bias-dependent spectral diversity to predict the continuous and arbitrary tunability of the DWELL detector within certain limits. This paper focuses on the experimental demonstration of the DWELL-based spectral tuning algorithm. It is shown experimentally that it is possible to reconstruct the spectral content of a target electronically without …

Mitochondrial Reactive Oxygen Species Production In Excitable Cells: Modulators Of Mitochondrial And Cell Function, David F. Stowe, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

The mitochondrion is a major source of reactive oxygen species (ROS). Superoxide (O₂^•−) is generated under specific bioenergetic conditions at several sites within the electron-transport system; most is converted to H₂O₂ inside and outside the mitochondrial matrix by superoxide dismutases. H₂O₂ is a major chemical messenger that, in low amounts and with its products, physiologically modulates cell function. The redox state and ROS scavengers largely control the emission (generation scavenging) of O₂^•−. Cell ischemia, hypoxia, or toxins can result in excess O₂^•− production when the redox …

Bioresorbable Film For The Prevention Of Adhesion To The Anterior Spine After Anterolateral Discectomy, Lisa S. Klopp, Jeffrey M. Toth, William C. Welch, Sangeeta Rao, Joseph W. Tai, Kevin A. Thomas, Simon Turner

Biomedical Engineering Faculty Research and Publications

Background context

The development of scar tissue and adhesions postoperatively is a natural consequence of healing but can be associated with medical complications and render reoperation difficult. Many biocompatible products have been evaluated as barriers or deterrents to adhesions.

Purpose

To evaluate the efficacy of a bioresorbable polylactide film as a barrier to adhesion formation after anterolateral discectomy.

Study design

Experimental study.

Methods

Seven, skeletally mature female sheep underwent a retroperitoneal approach to the anterolateral lumbar spine. A discectomy was performed at two levels with an intervening unoperated disc site. One site was treated with a polylactide film barrier (Hydrosorb …

Vascular Injury After Whole Thoracic X-Ray Irradiation In The Rat, S. N. Ghosh, Q. Wu, M. Mäder, B. L. Fish, John E. Moulder, Elizabeth R. Jacobs, Meetha Medhora, Robert C. Molthen

Biomedical Engineering Faculty Research and Publications

Purpose

To study vascular injury after whole thoracic irradiation with single sublethal doses of X-rays in the rat and to develop markers that might predict the severity of injury.

Methods and Materials

Rats that received 5- or 10-Gy thorax-only irradiation and age-matched controls were studied at 3 days, 2 weeks, and 1, 2, 5, and 12 months. Several pulmonary vascular parameters were evaluated, including hemodynamics, vessel density, total lung angiotensin-converting enzyme activity, and right ventricular hypertrophy.

Results

By 1 month, the rats in the 10-Gy group had pulmonary vascular dropout, right ventricular hypertrophy, increased pulmonary vascular resistance, increased dry lung …

Optimal Distributed Microphone Phase Estimation, Marek B. Trawicki, Michael T. Johnson

Dr. Dolittle Project: A Framework for Classification and Understanding of Animal Vocalizations

This paper presents a minimum mean-square error spectral phase estimator for speech enhancement in the distributed multiple microphone scenario. The estimator uses Gaussian models for both the speech and noise priors under the assumption of a diffuse incoherent noise field representing ambient noise in a widely dispersed microphone configuration. Experiments demonstrate significant benefits of using the optimal multichannel phase estimator as compared to the noisy phase of a reference channel.

Auditory Coding Based Speech Enhancement, Yao Ren, Michael T. Johnson

Dr. Dolittle Project: A Framework for Classification and Understanding of Animal Vocalizations

This paper demonstrates a speech enhancement system based on an efficient auditory coding approach, coding of time-relative structure using spikes. The spike coding method can more compactly represent the non-stationary characteristics of speech signals than the Fourier transform or wavelet transform. Enhancement is accomplished through the use of MMSE thresholding on the spike code. Experimental results show that compared with the spectral domain logSTSA filter, both the subjective spectrogram evaluation and objective SSNR improvement for the proposed approach is better in suppressing noise in high noise situations, with fewer musical artifacts.P

Analysis Of Load-Induced Strains In A Hot Mix Asphalt Perpetual Pavement, James Crovetti

Transportation Reports with the Wisconsin Department of Transportation

This report presents the findings of a research study conducted to investigate the structural performance of a 275 mm hot mix asphalt perpetual pavement constructed as part of the WIM bypass lane at the Kenosha Safety & Weigh Station Facility. Two separate test sections were constructed using variable binder types and in-place air voids. Asphalt strain sensors were fabricated at Marquette University and installed during the construction of the HMA pavement. Sensors were positioned within the outer wheel path and located at the bottom of the 275 mm HMA pavement and at the interface between the lower layers at a …

Ankle Load Modulates Hip Kinetics And Emg During Human Locomotion, Keith E. Gordon, Ming Wu, Jennifer H. Kahn, Yasin Y. Dhaher, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

The purpose of this research was to examine the role of isolated ankle-foot load in regulating locomotor patterns in humans with and without spinal cord injury (SCI). We used a powered ankle-foot orthosis to unilaterally load the ankle and foot during robotically assisted airstepping. The load perturbation consisted of an applied dorsiflexion torque designed to stimulate physiological load sensors originating from the ankle plantar flexor muscles and pressure receptors on the sole of the foot. We hypothesized that 1) the response to load would be phase specific with enhanced ipsilateral extensor muscle activity and joint torque occurring when unilateral …

A Comparison Of Pilot-Scale Photocatalysis And Enhanced Coagulation For Disinfection Byproduct Mitigation, Daniel Gerrity, Brooke Mayer, Hodon Ryu, John Crittenden, Morteza Abbaszadegan

Civil and Environmental Engineering Faculty Research and Publications

This study evaluated pilot-scale photocatalysis and enhanced coagulation for their ability to remove or destroy disinfection byproduct (DBP) precursors, trihalomethane (THM) formation potential (FP), and THMs in two Arizona surface waters. Limited photocatalysis (/m³) achieved reductions in most of the DBP precursor parameters (e.g., DOC, UV₂₅₄, and bromide) but led to increased chlorine demand and THMFP. In contrast, enhanced coagulation achieved reductions in the DBP precursors and THMFP. Extended photocatalysis (/m³) decreased THMFP once the energy consumption exceeded 20 kWh/m³. The photocatalytic energy requirements for THM destruction were considerably lower (EEO = …

Short-Term Osteoclastic Activity Induced By Locally High Concentrations Of Recombinant Human Bone Morphogenetic Protein–2 In A Cancellous Bone Environment, Jeffrey M. Toth, Scott D. Boden, J. Kenneth Burkus, Jeffrey Badura, Steve M. Peckham, William Mckay

Biomedical Engineering Faculty Research and Publications

Study Design. An experimental study investigating osteoclastic activity induced by rhBMP-2 in sheep.

Objective. To examine the effects of increasing local rhBMP-2 concentration on osteoclastic response and peri-implant bone resorption.

Summary of Background Data. Level I clinical studies have established the safe and effective volume and concentration of rhBMP-2 delivered on an absorbable collagen sponge. However, peri-implant bone resorption appearing as decreased mineral density has been observed radiographically in rare instances after implantation of rhBMP-2 on an absorbable collagen sponge (rhBMP-2/ACS).

Methods. Bilateral corticocancellous defects were created in the distal femora of 30 adult sheep. Combinations of rhBMP-2/ACS implant volume …

Effectiveness Of Temporary Traffic Control Measures In Highway Work Zones, Yingfeng Li, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

In the United States, hundreds of people lose their lives each year and many more are injured due to vehicle crashes in the work zones. Over the years, temporary traffic control (TCC) measures have been developed and deployed in work zones. To continuously improve the safety, there is a need to identify the traffic control deficiencies in work zones by evaluating the effectiveness of existing TTC measures based on the real crash cases. In this study, researchers evaluated the effectiveness of several commonly used TTC methods using logistic regression techniques and various significance test methods including likelihood ratio test, score …

Simulated Scatter Performance Of An Inverse-Geometry Dedicated Breast Ct System, Reema Bhagtani, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

The purpose of this work was to quantify the effects of scatter for inverse-geometry dedicated breast CT compared to cone-beam breast CT through simulations. The inverse geometry was previously proposed as an alternative to cone-beam acquisition for volumetric CT. The inverse geometry consists of a large-area scanned-source opposite a detector array that is smaller in the transverse direction. While the gantry rotates, the x-ray beam is rapidly sequenced through an array of positions, acquiring a truncated projection image at each position. Inverse-geometry CT (IGCT) is expected to detect less scatter than cone-beam methods because only a fraction of the object …

Imaging Radiation Pneumonitis In A Rat Model Of A Radiological Terrorism Incident, Robert C. Molthen, Qingping Wu, Gary S. Krenz, Meetha Medhora, Elizabeth R. Jacobs, John E. Moulder

Biomedical Engineering Faculty Research and Publications

We have developed a rat model of single, sub-lethal thoracic irradiation. Our irradiation protocol is considered representative of exposures near the detonation site of a dirty bomb or small nuclear device. The model is being used to investigate techniques for identifying, triaging and treating possible victims. In addition to physiological markers of right ventricular hypertrophy, pulmonary vascular resistance, and arterial distensibility, we present two methods for quantifying microvascular density. We used methods including microfocal X-ray imaging to investigate changes in lung structure/function resulting from radiation exposure. Radiation pneumonitis is a complication in subjects receiving thoracic irradiation. A radiographic hallmark of …

A Pilot Study Evaluating Use Of A Computer-Assisted Neurorehabilitation Platform For Upper-Extremity Stroke Assessment, Xin Feng, Jack Winters

Electrical and Computer Engineering Faculty Research and Publications

Background

There is a need to develop cost-effective, sensitive stroke assessment instruments. One approach is examining kinematic measures derived from goal-directed tasks, which can potentially be sensitive to the subtle changes in the stroke rehabilitation process. This paper presents the findings from a pilot study that uses a computer-assisted neurorehabilitation platform, interfaced with a conventional force-reflecting joystick, to examine the assessment capability of the system by various types of goal-directed tasks.

Methods

Both stroke subjects with hemiparesis and able-bodied subjects used the force-reflecting joystick to complete a suite of goal-directed tasks under various task settings. Kinematic metrics, developed for specific …