Matching Items (296)
Description
In many systems, it is difficult or impossible to measure the phase of a signal. Direct recovery from magnitude is an ill-posed problem. Nevertheless, with a sufficiently large set of magnitude measurements, it is often possible to reconstruct the original signal using algorithms that implicitly impose regularization conditions on this ill-posed problem. Two such algorithms were examined: alternating projections, utilizing iterative Fourier transforms with manipulations performed in each domain on every iteration, and phase lifting, converting the problem to that of trace minimization, allowing for the use of convex optimization algorithms to perform the signal recovery. These recovery algorithms were compared on a basis of robustness as a function of signal-to-noise ratio. A second problem examined was that of unimodular polyphase radar waveform design. Under a finite signal energy constraint, the maximal energy return of a scene operator is obtained by transmitting the eigenvector of the scene Gramian associated with the largest eigenvalue. It is shown that if instead the problem is considered under a power constraint, a unimodular signal can be constructed starting from such an eigenvector that will have a greater return.
ContributorsJones, Scott Robert (Author) / Cochran, Douglas (Thesis director) / Diaz, Rodolfo (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2014-05
Description
The project described here is a solar powered intrusion detection system consisting of three modules: a battery recharging circuit, a laser emitter and photodetector pair, and a Wi- Fi connectivity board. Over the preceding seven months, great care has been taken for the design and construction of this system. The first three months were spent researching and selecting suitable IC's and external components (e.g. solar panel, batteries, etc.). Then, the next couple of months were spent ordering specific materials and equipment for the construction of our prototype. Finally, the last two months were used to build a working prototype, with a substantial amount of time used for perfecting our system's packaging and operation. This report will consist of a detailed discussion of our team's research, design activities, prototype implementation, final budget, and final schedule. Technical discussion of the concepts behind our design will assist with understanding the design activities and prototype implementation sections that will follow. Due to the generous funding of the group from the Barrett Honors College, our overall budget available for the project was $1600. Of that amount, only $334.51 was spent on the actual system components, with $829.42 being spent on the equipment and materials needed for the testing and construction of the prototype. As far as the schedule goes, we are essentially done with the project. The only tasks left to finish are a successful defense of the project at the oral presentation on Friday, 29 March 2013, followed by a successful demo on 26 April 2013.
ContributorsTroyer, Nicole L. (Co-author) / Shtayer, Idan (Co-author) / Guise, Chris (Co-author) / Kozicki, Michael (Thesis director) / Roedel, Ronald (Committee member) / Goodnick, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2013-05
Description
This report outlines the current methods and instrumentation used for diabetes monitoring and detection, and evaluates the problems that these methods face. Additionally, it will present an approach to remedy these problems. The purpose of this project is to create a potentiostat that is capable of controlling a diabetes meter that monitors multiple biological markers simultaneously. Glucose is the most commonly measured biomarker for diabetes. However, it provides only a limited amount of information. In order to give the user of the meter more information about the progression of his or her disease, the concentrations of several different biological markers for diabetes may be measured using a system that operates in a similar fashion to blood glucose meters. The potentiostat provides an input voltage into the electrode sensor and receives the current from the sensor as the output. From this information, the impedance may be calculated. The concentrations of each of the biomarkers in the blood sample can then be determined. In an effort to increase sensitivity, the diabetes meter forgoes the use of amperometric i-t in favor of the electrochemical impedance spectroscopy technique. A three-electrode electrochemical sensor is used with the meter. In order to perform simultaneous and rapid testing of biomarker concentration, a single multisine input wave is generated using a hardware implementation of a summing amplifier and waveform generators.
ContributorsWu, Diane Zhang (Author) / LaBelle, Jeffrey (Thesis director) / Bakkaloglu, Bertan (Committee member) / Spano, Mark (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2013-05
Description
The problem of detecting the presence of a known signal in multiple channels of additive white Gaussian noise, such as occurs in active radar with a single transmitter and multiple geographically distributed receivers, is addressed via coherent multiple-channel techniques. A replica of the transmitted signal replica is treated as a one channel in a M-channel detector with the remaining M-1 channels comprised of data from the receivers. It is shown that the distribution of the eigenvalues of a Gram matrix are invariant to the presence of the signal replica on one channel provided the other M-1 channels are independent and contain only white Gaussian noise. Thus, the thresholds representing false alarm probabilities for detectors based on functions of these eigenvalues remain valid when one channel is known to not contain only noise. The derivation is supported by results from Monte Carlo simulations. The performance of the largest eigenvalue as a detection statistic in the active case is examined, and compared to the normalized matched filter detector in a two and three channel case.
ContributorsBeaudet, Kaitlyn Elizabeth (Author) / Cochran, Douglas (Thesis director) / Wu, Teresa (Committee member) / Howard, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2013-05
Description
The nonmedical use of prescription ADHD medications by American college students for the purpose of enhancing academic performance has been well-documented for more than a decade. A closer look at this trend through the lens of biomedicalization theory shows us that this behavior, which is often dismissed as a simple abuse of the system by deviant young people, is consistent with broader trends in post-modern medicine and health. The goal of this project was to describe the biomedicalization of studying by illustrating the historical, sociocultural, and politico-economic roots of nonmedical stimulant use by college students in the United States. An online survey was administered to students at ASU and responses from students studying in the College of Liberal Arts and Sciences (n=233) were analyzed. A 12.4% lifetime prevalence of illicit stimulant use was found among the sample population. Thematic analysis was performed on students' open-ended commentary and several themes related to the biomedicalization framework were uncovered including Necessity, Identity, Inextricability from academia, and Trust in the system. Through these themes it was found that many of the theorized transitions of biomedicalization were visible in the data set, confirming the idea that nonmedical stimulant use is embedded in the complex network of processes that represents post-modern medicine today.
ContributorsStevenson, Christine Renee (Author) / Brian, Jennifer (Thesis director) / Robert, Jason (Committee member) / Caniglia, Guido (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / Department of Chemistry and Biochemistry (Contributor)
Created2014-05
Description
The first global estimate of maternal mortality in 1985 revealed that over half a million women die each year due to pregnancy related causes. Although a relatively small figure compared to the deaths attributed to such diseases as malaria and HIV, this was new data. New data meant attraction from powerful international agency leaders, which eventually led to the formation of a global effort called the Safe Motherhood Initiative (SMI). In turn, the global SMI provided the framework for the World Health Organization's (WHO) Millennium Development Goal 5 (MDG 5). Both of these global campaigns, which were largely implemented through advocacy efforts, adopted time sensitive goals aimed specifically to decrease maternal mortality. Although the placement of maternal health on the public health agenda was an extraordinary accomplishment for women's health advocates, a historical examination of safe motherhood efforts will reveal that these advocacy techniques would not keep maternal health on the public health agenda. Over two decades of unsuccessful efforts to reduce maternal mortality have shown that advocacy efforts are not the answer to actually decreasing maternal mortality ratios. Due to the intrinsic difficulties in measuring maternal mortality, and the public health sector's emphasis in prioritizing the political agenda based on such measurements, maternal health has arguably fallen in last place on the agenda. This thesis will explore how the concern for mothers influenced the formation of MDG 5, and how MDG 5 has been translated into local practices. A case study of the Pan American Health Organization's advocacy effort also called the Safe Motherhood Initiative explores the underlying, culturally complex problems that are hindering progress of MDG 5. The results show that the lack of comprehensive reproductive health services for women is not only due to poor health systems in place, which is what many safe motherhood 5 efforts have attempted to address, but also due to cultural traditions and laws on sexual and reproductive health forbidding women to obtain the care they need to survive.
ContributorsAntonios, Nathalie (Author) / Hurlbut, Ben (Thesis director) / Brian, Jennifer (Committee member) / Ellison, Karin (Committee member) / Barrett, The Honors College (Contributor)
Created2013-12
Description
Electroencephalogram (EEG) used simultaneously with video monitoring can record detailed patient physiology during a seizure to aid diagnosis. However, current patient monitoring systems typically require a patient to stay in view of a fixed camera limiting their freedom of movement. The goal of this project is to design an automatic patient monitoring system with software to track patient movement in order to increase a patient's mobility. This report discusses the impact of an automatic patient monitoring system and the design steps used to create and test a functional prototype.
ContributorsBui, Robert Truong (Author) / Frakes, David (Thesis director) / Helms Tillery, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2014-05
Description
MESFETs are used in high frequency applications and are typically made from GaAs. Dr. Trevor Thornton designed a silicon-on-insulator MESFET \u2014 a cheaper alternative with competitive capabilities. This paper concerns the characterization and modeling of this device to exhibit its marketability as a CMOS integrated transistor. Overviews of the MESFET's history and DLTS (deep level transient spectroscopy) are offered.
ContributorsTerrell, Catherine Elaine (Author) / Thornton, Trevor (Thesis director) / Young, Alexander (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2014-05
Description
A novel strain sensing procedure using an optical scanning methodology and diffraction grating is explored. The motivation behind this study is due to uneven thermal strain distribution across semiconductor chips that are composed of varying materials. Due to the unique properties of the materials and the different coefficients of thermal expansion (CTE), one can expect the material that experiences the highest strain to be the most likely failure point of the chip. As such, there is a need for a strain sensing technique that offers a very high strain sensitivity, a high spatial resolution while simultaneously achieving a large field of view. This study goes through the optical setup as well as the evolution of the optical grating in an effort to improve the strain sensitivity of this setup.
ContributorsChen, George (Co-author) / Ma, Teng (Co-author) / Liang, Hanshuang (Co-author) / Song, Zeming (Co-author) / Nguyen, Hoa (Co-author) / Yu, Hongbin (Thesis director) / Jiang, Hanqing (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2014-05
Description
Head's up displays (HUD) are now emerging into the technological market that is used in various functionalities, but most of all, they are expensive. An alternative method to find cheaper ways to develop a head's up display is researched and implemented. The HUD is equipped with a processor and projector. Both of these hardware components encompasses most part of the HUD along with some manipulation of the material that the image is projected on. In this study, the software and the optics of the HUD will be explored and lastly, taking into full consideration on the future work that can be done to make improvements on the HUD.
ContributorsKim, Lilian SA (Author) / Goryll, Michael (Thesis director) / Zhang, Yong-Hang (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor)
Created2014-05