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Recent advances in camera architectures and associated mathematical representations now enable compressive acquisition of images and videos at low data-rates. While most computer vision applications of today are composed of conventional cameras, which collect a large amount redundant data and power hungry embedded systems, which compress the collected data for further processing, compressive cameras offer the advantage of direct acquisition of data in compressed domain and hence readily promise to find applicability in computer vision, particularly in environments hampered by limited communication bandwidths. However, despite the significant progress in theory and methods of compressive sensing, little headway has been made in developing systems for such applications by exploiting the merits of compressive sensing. In such a setting, we consider the problem of activity recognition, which is an important inference problem in many security and surveillance applications. Since all successful activity recognition systems involve detection of human, followed by recognition, a potential fully functioning system motivated by compressive camera would involve the tracking of human, which requires the reconstruction of atleast the initial few frames to detect the human. Once the human is tracked, the recognition part of the system requires only the features to be extracted from the tracked sequences, which can be the reconstructed images or the compressed measurements of such sequences. However, it is desirable in resource constrained environments that these features be extracted from the compressive measurements without reconstruction. Motivated by this, in this thesis, we propose a framework for understanding activities as a non-linear dynamical system, and propose a robust, generalizable feature that can be extracted directly from the compressed measurements without reconstructing the original video frames. The proposed feature is termed recurrence texture and is motivated from recurrence analysis of non-linear dynamical systems. We show that it is possible to obtain discriminative features directly from the compressed stream and show its utility in recognition of activities at very low data rates.
ContributorsKulkarni, Kuldeep Sharad (Author) / Turaga, Pavan (Thesis advisor) / Spanias, Andreas (Committee member) / Frakes, David (Committee member) / Arizona State University (Publisher)
Created2012
Description
In this study, the specific goal was to evaluate the effectiveness of utilizing a novel virtual reality software package with a haptic device to practice spine surgery. This spine surgery simulator was commissioned by Barrow Neurological Institute (BNI) and is as yet untested. To test the simulator, an experiment was run in which resident neurosurgeons at Barrow Neurological Institute were asked to perform two “virtual surgeries” with the spine surgical simulator, provide observations on the simulator, and then complete a questionnaire evaluating different aspects of the simulator. The mean questionnaire score across all the neurosurgical residents was found to be 65.5 % ± 9.4 % of the maximum score which suggests that certain aspects of the virtual spine surgical simulator were deemed to be effective by the resident neurosurgeons but that improvements need to be made for the simulator to be fully ready as a teaching and planning tool. As of right now, the simulator is more suited as a training tool instead of a planning tool. Improvements that should be implemented include changing the hardware placement of the haptic device and the computer, minimizing aberrant tactile feedback, and adding anatomical and planning detail to the software to provide a more accurate reflection of spine surgery. It was also suggested that future experiments that evaluate an improved simulator should ensure that participants are trained adequately and have enough time to complete surgical operations to get a fair assessment of the tool.
ContributorsIyer, Sudarshan Rajan (Author) / Frakes, David (Thesis director) / Crawford, Neil (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
Description
A specific type of Congenital Heart Defect (CHD) known as Coarctation (narrowing) of the Aorta (CoA) prevails in 10% of all CHD patients resulting in life-threatening conditions. Treatments involve limited medical therapy (i.e PGE1 therapy), but in majority of CoA cases, planned surgical treatments are very common. The surgical approach is dictated by the severity of the coarctation, by which the method of treatments is divided between minimally invasive and extensive invasive procedures. Modern diagnostic procedures allude to many disadvantages making it difficult for clinical practices to properly deliver an optimal form of care. Computational Fluid Dynamics (CFD) technique addresses these issues by providing new forms of diagnostic measures that is non-invasive, inexpensive, and more accurate compared to other evaluative devices. To explore further using the CFD based alternative diagnostic measure, this project aims to validate CFD techniques through in vitro studies that capture the fluid flow in anatomically accurate aortic structures. These studies combine particle image velocimetry and catheterization experimental techniques in order to provide a significant knowledge towards validation of fluid flow simulations.
ContributorsPathangey, Girish (Co-author) / Matheny, Chris (Co-author) / Frakes, David (Thesis director) / Pophal, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
Description
Bacteria play a vital role in the world ecosystem, more importantly human health and disease. The capability to differentiate and identify these microorganisms serves as an important research objective. In past years, separations-based approaches have served as a way to observe and identify bacteria based on their characteristics. Gradient insulator dielectrophoresis (g-iDEP) provides benefits in identifying serotypes of a single species with precise separation. Separation of Staphylococcus epidermidis in a single g-iDEP microchannel is conducted exploiting their electrophoretic and electrokinetic properties. The cells were captured and concentrated at gates with interacting forces within the microchannel to clearly distinguish between the two strains. These results provide support for g-iDEP serving as a separating method and, furthermore, future clinical applications.
ContributorsDavis, Paige Elizabeth (Author) / Hayes, Mark (Thesis director) / Borges, Chad (Committee member) / Jones, Paul (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / T. Denny Sanford School of Social and Family Dynamics (Contributor)
Created2015-05
Description
This study investigates the application of Computational Fluid Dynamics (CFD) to the medical field. An overview of recent advances in computational simulation and modeling in medical applications is provided, with a particular emphasis on CFD. This study attempts to validate CFD and demonstrate the possibility for applying CFD to the clinical treatment and evaluation of atherosclerotic disease. Three different geometric configurations are investigated: one idealized bifurcation with a primary diameter of 8 mm, and two different patient-specific models of the bifurcation from the common femoral artery to the superficial and deep femoral arteries. CFD is compared against experimental measurements of steady state and pulsatile flow acquired with Particle Image Velocimetry (PIV). Steady state and pulsatile flow rates that are consistent with those observed in the femoral artery are used. In addition, pulsatile CFD simulations are analyzed in order to demonstrate meaningful clinical applications for studying and evaluating the treatment of atherosclerotic disease. CFD was successfully validated for steady state flow, with an average percent error of 6.991%. Potential for validation was also demonstrated for pulsatile flow, but methodological errors warrant further investigation to reformulate methods and analyze results. Quantities frequently associated with atherosclerotic disease and arterial bifurcations, such as large variations in wall shear stress and the presence of recirculation zones are demonstrated from the pulsatile CFD simulations. Further study is required in order to evaluate whether or not such phenomena are represented by CFD accurately. Further study must also be performed in order to evaluate the practicality and utility of CFD for the evaluation of atherosclerotic disease treatment.
ContributorsMortensen, Matthew James (Author) / VanAuker, Michael (Thesis director) / Frakes, David (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Background: High risk types of human papillomavirus (HPV) are known to cause cancer, including cervical (99%) and oropharyngeal cancer (70%). HPV type 16 is the most common subtype. Three antigens that are critical for integration or tumor progression are E2, E6 and E7. In this study, we developed a systematic approach to identify naturally-processed HPV16-derived HLA class I epitopes for immunotherapy development. Methods: K562 cells, which lack HLA expression, were transduced with each HPV16 antigen using lentivirus and supertransfected with HLA-A2 by nucleofection. Stable cell lines expressing each antigen were selected for and maintained throughout the investigation. In order to establish a Gateway-compatible vector for robust transient gene expression, a Gateway recombination expression cloning cassette was inserted into the commercial Lonza pMAX GFP backbone, which has been experimentally shown to display high transfection expression efficiency. GFP was cloned into the vector and plain K562 cells were transfected with the plasmid by nucleofection. Results: Expression of K562-A2 was tested at various time points by flow cytometry and A2 expression was confirmed. Protein expression was shown for the transduced K562 E7 by Western blot analysis. High transfection efficiency of the pMAX_GFP_Dest vector (up to 97% GFP+ cells) was obtained 48 hours post transfection, comparable to the commercial GFP-plasmid. Conclusion: We have established a rapid system for target viral antigen co-expression with single HLA molecules for analysis of antigen presentation. Using HPV as a model system, our goal is to identify specific antigenic peptide sequences to develop immunotherapeutic treatments for HPV-associated cancers.
ContributorsVarda, Bianca Marie (Author) / Anderson, Karen (Thesis director) / Borges, Chad (Committee member) / Krishna, Sri (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Glioblastoma Multiforme (GBM) is an aggressive and deadly form of brain cancer with a median survival time of about a year with treatment. Due to the aggressive nature of these tumors and the tendency of gliomas to follow white matter tracks in the brain, each tumor mass has a unique growth pattern. Consequently it is difficult for neurosurgeons to anticipate where the tumor will spread in the brain, making treatment planning difficult. Archival patient data including MRI scans depicting the progress of tumors have been helpful in developing a model to predict Glioblastoma proliferation, but limited scans per patient make the tumor growth rate difficult to determine. Furthermore, patient treatment between scan points can significantly compound the challenge of accurately predicting the tumor growth. A partnership with Barrow Neurological Institute has allowed murine studies to be conducted in order to closely observe tumor growth and potentially improve the current model to more closely resemble intermittent stages of GBM growth without treatment effects.
ContributorsSnyder, Lena Haley (Author) / Kostelich, Eric (Thesis director) / Frakes, David (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Intracranial aneurysms are blood \u2014filled sacs along the blood vessels in the brain. These aneurysms can be particularly dangerous due to difficulty in detection and potential lifethreatening outcome. When these aneurysms are detected, there are few treatment options to prevent rupture, one of which is endovascular stents. By placing a stent across the parent vessel, blood flow can be diverted from the aneurysm. Reduced flow reduces the chance of rupture and promotes clotting within the aneurysm. In this study, hemodynamics in idealized basilar tip aneurysm models were investigated at three flow rates using particle imaging velocimetry (PIV). Two models were created with increasing dome size (4mm vs 6mm), and constant dome-to-neck ratio (3:2) and parent vessel contact angle to represent growing aneurysm. With the pulsatile flow, data is acquired at three separate points in the cardiac cycle. Both of the models were studied untreated, treated with Enterprise stent and treated with Pipeline stent. Enterprise stent was developed mainly for structural support while the Pipeline stent was developed as a flow diverter. Due to target functions of the stents, Enterprise stent is more porous than the Pipeline stent. Hemodynamics were studied using a stereo particle image velocimetry technique. The flow in models was characterized by neck and aneurysmal RMS velocity, neck and aneurysm kinetic energy, cross neck flow. It was found that both of the stents are capable diverting flow. Enterprise reduced aneurysmal RMS velocity in model 1 by 38.7% and in model 2 by 76.2%. Pipeline stent reduced aneurysmal RMS velocity in model 1 by 71.4% and in model 2 by 88.1%. Both reductions are data for 3ml/s at peak systole pulsatile flow. Data shows that the Pipeline stent is better than Enterprise stent at reducing flow to the aneurysm.
ContributorsChung, Hanseung (Author) / Frakes, David (Thesis director) / Caplan, Michael (Committee member) / Babiker, Haithem (Committee member) / Barrett, The Honors College (Contributor) / Economics Program in CLAS (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
The Honors Thesis involved the use of vertically-aligned, piezoelectric nanowire sensor arrays configured by Dr. Henry A. Sodano and Dr. Aneesh Koka from the University of Florida, in order to acquire acceleration data. Originally, the project was focused on interfacing and calibrating the barium titanate (BaTio3) sensors to measure wall shear stress, a fluid dynamic characteristic. In order to gain an understanding of these novel piezoelectric sensors, the experiments performed by Sodano and Koka were to be investigated, replicated, and results reproduced. After initial trial phases, signals failed to be consistently measured from the sensors and the project's emphasis was re-defined. The outlined goals were 1) to re-design the initial system used for signal acquisition, 2) test the improved signal acquisition system, 3) successfully measure output signals from the BaTiO3 nanowire sensors, and 4) determine the cause for inconsistent signal measurements from the piezoelectric nanawire sensors. Following a detailed review of the previous experimental procedures and the initial signal acquisition system, an improved acquisition system was designed and its expected behavior was tested and verified. Despite the introduction of the improved acquisition system, voltage outputs were unable to be measured as a function of shaker table acceleration. It was impossible to verify the effect of the improved signal acquisition system on the measured BaTiO3 nanowire sensor output. Based on an analysis of data collected using a commercial 3-axis acceleromoeter, it is hypothesized that the BaTiO3 nanowire sensors were broken after the first experimental trial due to an excessively applied force from an external source (i.e. shaker table, improper handling during experimentation, and/or improper handling during transportation).
ContributorsThomas, Jonah (Author) / Frakes, David (Thesis director) / LaBelle, Jeffrey (Contributor) / Barrett, The Honors College (Contributor)
Created2014-05
Description
Cerebral aneurysms, also known as intracranial aneurysms, are sac-like lesions in the arteries of the brain that can rupture to cause subarachnoid hemorrhaging, damaging and killing brain cells. Metal coil embolization has been traditionally used to occlude and treat cerebral aneurysms to limited success, but polymer embolization has been suggested, because it can provide a greater fraction of occlusion. One such polymer with low cytotoxicity is poly(propylene glycol)diacrylate (PPODA) crosslinked via Michael-type addition with pentaerythritol tetrakis(3-mercaptopropionate) (QT). This study was performed to examine the behavior of PPODA-QT gel in vitro under pulsatile flow emulating physiological conditions. An idealized cerebral aneurysm flow model was designed based on geometries associated with an increase in rupture risk. Pressure was monitored at the apex of the aneurysm dome for varied flow rates and polymer filling fractions of 32.4, 78.2, and 100%. The results indicate that the amount of PPODA-QT deployed into the aneurysm decreases the peak-to-peak oscillation in pressure at the aneurysm wall by an inverse proportion. The 32.4 and 78.2% treatments did not significantly decrease the mean pressure applied to the aneurysm dome, but the 100% treatment greatly reduced it by diverting flow. This study indicates that the maximum filling fraction after swelling of PPODA-QT polymer should be deployed into the aneurysmal sac for treatment.
ContributorsWorkman, Christopher David (Author) / Vernon, Brent (Thesis director) / Frakes, David (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05