Search Results (1 - 10 of 10 Results)

Sort By  
Sort Dir
 
Results per page  

Scott, Kevon KOcclusion-Aware Sensing and Coverage in Unmanned Aerial Vehicle (UAV) Networks
MS, University of Cincinnati, 2016, Engineering and Applied Science: Computer Engineering
The use of small and miniature Unmanned Aerial Vehicles (UAVs) for remote sensing and surveillance applications has become increasingly popular in the last two decades. Networks of UAVs, capable of providing flexible aerial views over large areas, are playing important roles in today's distributed sensing systems. Since camera sensors are sensitive to occlusions, it is more challenging to deploy UAVs for sensing in geometrically complex environments, such as dense urban areas and mountainous terrains. The intermittent connectivity in a sparse UAV network also makes it challenging to efficiently gather sensed multimedia data. This thesis is composed of two pieces of work. In the first piece of work, a new occlusion-aware UAV coverage technique with the objective of sensing a target area with satisfactory spatial resolution subject to the energy constraints of UAVs is proposed. An occlusion-aware waypoint generation algorithm is first designed to find the best set of waypoints for taking pictures in a target area. The selected waypoints are then assigned to multiple UAVs by solving a vehicle routing problem (VRP), which is formulated to minimize the maximum energy for the UAVs to travel through the waypoints. A genetic algorithm is designed to solve the VRP problem. Evaluation results show that the proposed coverage technique can reduce energy consumption while achieving better coverage than traditional coverage path planning techniques for UAVs. In the second piece of work, a communication scheme is designed to deliver the images sensed by a set of mobile survey UAVs to a static base station through the assistance of a relay UAV. Given the planned routes of the survey UAVs, a set of relay waypoints are found for the relay UAV to meet the survey UAVs and receive the sensed images. An Online Message Relaying technique (OMR) is proposed to schedule the relay UAV to collect images. Without any global collaboration between the relay UAV and the survey UAVs, OMR utilizes a markov decision process (MDP) that determines the best schedules for the relay UAV such that the image acquisition rate could be maximized. Evaluation results show that the proposed relaying technique outperforms traditional relaying techniques, such as the traveling salesman problem (TSP) and the random walk, in terms of end-to-end delay and frame delivery ratio.

Committee:

Rui Dai, Ph.D. (Committee Chair); Dharma Agrawal, D.Sc. (Committee Member); Carla Purdy, Ph.D. (Committee Member)

Subjects:

Computer Engineering

Keywords:

Unmanned Aerial Vehicle;UAV;Occlusion;FANET;Flying Ad-Hoc Networks;Remote Sensing

Cayot, Trent EThe Effect of Blood Flow Restriction Techniques during Aerobic Exercise in Healthy Adults
Doctor of Philosophy, University of Toledo, 2015, Exercise Science
Although the importance of aerobic exercise in disease prevention and maintenance of a healthy lifestyle has been extensively demonstrated [1-4], it was recently reported by the American Heart Association (AHA) that approximately 30% of the adult population within the United States does not engage in regular aerobic exercise [2]. The most commonly reported reason why adults did not engage in regular exercise was due to a "lack of time" within their daily routine [5, 6]. In order to best integrate exercise into a time constrained schedule many have turned to high-intensity interval training (HIIT) due to the advantageous training outcomes reported in a relatively short duration (2-4 week) [7, 8]. In addition, the exercise volume is significantly reduced (~80-90%) during HIIT sessions compared to traditional "continuous" cardiovascular exercise sessions [8, 9] thus decreasing the time spent exercising [8]. However, the exercise intensities used during HIIT sessions ("all-out effort" [9, 10] or near maximal intensities [11, 12]) may become a deterrent or may not be appropriate for certain populations. An exercise technique known as blood flow restriction (BFR) exercise may be an acceptable alternative approach for these populations as it utilizes low exercise intensities. BFR exercise has been shown to concurrently increase muscle hypertrophy [13, 14], muscle strength [13] and peak oxygen uptake (VO2pk) [14, 15] subsequent to low-intensity (i.e., walking, cycling) cardiovascular training programs. The combination of BFR (i.e., decreased exercise intensity) and interval training (i.e., decreased exercise volume) is both intriguing and a unique alternative solution that could potentially be applicable to a variety of populations. This alternative exercise approach (i.e., BFR interval training) addresses many commonly cited barriers for exercise retention (i.e., time constrained schedules, high exercise intensities). Therefore, the primary purpose of this dissertation was to determine the results of a short duration (2 weeks) BFR low-intensity interval training (BFR-LIIT) program on aerobic capacity and skeletal muscle strength (chapter 5). However, before the primary purpose could be investigated many secondary aims needed to be examined, including i) determining the effect of occlusion duration on the microvascular oxygenation and neuromuscular activation during exercise (chapter 3) and ii) determining the acute physiological responses (oxygen uptake, microvascular oxygenation, neuromuscular activation) to BFR used in cardiovascular exercise models (constant load, chapter 4; interval, chapter 5). The effects of occlusion duration were examined as healthy subjects performed isometric knee extension contractions at different sub-maximal intensities under control (CON, no occlusion), immediate occlusion (IO) and pre occlusion (PO) conditions. During the IO condition the occlusion pressure (130% of the resting systolic blood pressure, 130% SBP) was applied immediately prior to exercise while the occlusion pressure (130% SBP) was applied five minutes prior to exercise in the PO condition. Varying the occlusion duration did not affect the neuromuscular activation of the exercising musculature (p > 0.05), although activation did significantly increase with increasing sub-maximal exercise intensities. However, PO elicited greater microvascular deoxygenation (deoxy-[Hb+Mb]), as assessed by near-infrared spectroscopy) compared to CON at all exercise intensities (p < 0.05), whereas the deoxy-[Hb+Mb] was only greater during PO compared to IO at the lowest exercise intensity tested (20% maximal voluntary contraction, MVC). Furthermore, IO resulted in greater deoxy-[Hb+Mb] compared to CON only at low exercise intensities (20% MVC, 40% MVC). In conclusion, although occlusion duration did significantly affect neuromuscular activation, BFR techniques influenced microvascular oxygenation the most during low-intensity exercise. Many investigations have observed an increased neuromuscular activation with BFR resistance exercise [16-19], however, the peripheral responses (i.e., neuromuscular activation, microvascular oxygenation) to BFR cardiovascular exercise (i.e., cycling) has yet to be determined. Therefore, healthy subjects performed bouts of heavy (above estimated lactate threshold, >LT) constant cycling exercise with and without BFR. No difference in oxygen uptake (VO2) was observed (p > 0.05) despite a greater deoxy-[Hb+Mb] response during the beginning and end of BFR exercise compared to control (CON) exercise (p < 0.05). Unlike previous BFR resistance training investigations [16-19], BFR cycling exercise resulted in significantly lower neuromuscular activation during the end of exercise. Additionally each exercise condition elicited an increase in blood lactate concentration (from 20 watt baseline cycling to immediately post-exercise), however, plasma vascular endothelial growth factor receptor 2 was not significantly affected subsequent to any exercise condition. These results may suggest that the perturbation caused by BFR during low-intensity cycling exercise may have a greater localized affect within the exercising muscle, similar to previous investigations [20-23]. Lastly, healthy subjects completed a short duration BFR low-intensity interval training (BFR-LIIT) program on a cycle ergometer. The subjects performed 8-12 intervals at 40% VO2pk during six exercise sessions across two weeks. During the BFR-LIIT sessions continuous bilateral occlusion was applied to the proximal thigh at an occlusion pressure of 130% SBP. Significant increases in the estimated LT and knee extensor strength (isometric, eccentric) were observed following BFR-LIIT. However, no changes were detected in VO2pk and oxidative phosphorylation capacity at the level of the mitochondria (assessed from the phase II oxygen uptake time constant). Collectively all of the investigations suggest that the perturbation induced by BFR techniques during cardiovascular exercise has a greater localized affect within the exercising musculature. Furthermore, we suggest that exercise volume is more heavily relied upon to induce significant training stimuli during BFR exercise since the exercise intensity is reduced. This could explain the lack of increase in VO2pk (3.3%) following BFR-LIIT as a low exercise volume (interval exercise, 2 weeks) was combined with low-intensity exercise. Therefore, the findings within this dissertation would not recommend the use of BFR during short duration (2 weeks), low volume (interval) exercise programs if the training objectives include significant peak cardiovascular adaptations (VO2pk). Future investigation into an appropriate dose response of BFR low-intensity exercise and exercise volume is required to explain previous reports of increases in VO2pk subsequent to BFR training [14, 15]. However, rapid improvements in muscle strength and sub-maximal aerobic capacity (estimated LT) were observed with BFR-LIIT that may have considerable applicability to certain populations.

Committee:

Barry Scheuermann (Advisor); Suzanne Wambold (Committee Member); Michael Tevald (Committee Member); David Weldy (Committee Member)

Subjects:

Health Sciences; Physiology

Keywords:

Blood Flow Restriction; Occlusion; KAATSU; Aerobic Exercise

Cheng, XinhuaThe Effects of AcMNPV fp25k Mutations on Very Late Gene Expression and Virion Occlusion in Insects and Insect Cells
Doctor of Philosophy, Miami University, 2012, Cell, Molecular and Structural Biology (CMSB)
Baculoviruses are promising for bio-control of insect pests in agriculture and have been used for exogenous protein expression. Autographa californica multiple nucleopolyhedrovirus (AcMNPV) has been widely studied for baculovirus early and late gene transcription in insect cell lines such as Sf21, Sf9 derived from Spodoptera frugiperda and High Five™ (Hi5) from Trichoplusia ni. AcMNPV expresses high levels of the polyhedrin (polh) protein which can occlude virions into polyhedra for protection from UV irradiation in the field. The AcMNPV fp25k gene is prone to mutation during high multiplicity of infection (MOI) of insect cells and fp25k mutation can lead to the development of few polyhedra (FP)/cell phenotype in contrast to a multiple polyhedra (MP)/cell phenotype of the wild type fp25k mutant viruses have been reported to have reduced polyhedrin expression and reduced virion occlusion which leads to low expression of foreign gene, low yield and poor quality of bio-insecticide. Here, we found that AcMNPV fp25k contains two 7 adenine (A7) mononucleotide repeats (MNRs) that were mutated to A8 MNRs and the 10th TTAA site contains a 287 bp cellular DNA insertion during passage in Sf21 cells to form fp25k mutants. Sf9 and Hi5 cell lines infected with the mutant viruses only showed the typical FP whereas many Sf21 cells showed MP. The mutant viruses had reduced polh mRNA and protein expression levels in Sf9 and Hi5 but not in Sf21 cell line. Clusters of MP were observed in the fat body cells of T. ni and S. frugiperda larvae infected with mutant viruses. Although MP were produced in both insects, virion occlusion occurred in T. ni larval fat body and Hi5 cells but not in S. frugiperda fat body, Sf21 and Sf9 cell lines. Transmission electron microcopy revealed that some fat body cells of T. ni larvae produced MP filled with virions. Therefore, insect cells that showed better protein expression and/or virion occlusion should be cloned for improved viral insecticide development and for improved protein expression. Further evidence demonstrated that elimination of the mutation sites of AcMNPV fp25k delayed FP development and improved polyhedra production for better viral insecticide production.

Committee:

Xiao-Wen Cheng, PhD (Advisor); Gary R. Janssen, PhD (Committee Member); Joseph M. Carlin, PhD (Committee Member); Eileen K. Bridge, PhD (Committee Chair); Haifei Shi, PhD (Committee Member)

Subjects:

Virology

Keywords:

AcMNPV; fp25k; gene expression; insect cells; mutation mechanism; transposition; polyhedrin promoter; polyhedra production; few polyhedra in fat body cells; virion occlusion; mononucleotide repeats; DNA replication slippage; virus serial passage in cells

Lao, YuanweiVisual Tracking by Exploiting Observations and Correlations
Doctor of Philosophy, The Ohio State University, 2010, Electrical and Computer Engineering

When more video cameras are employed in a wide range of applications, how to understand this huge amount of video data in an automatic way becomes a urgent task. Visual tracking is such a strong tool used to abstract the high-level information, such as human activity recognition, traffic information accumulation, security event detection, etc. However, efficiency is still one major issue limiting tracking algorithms in many real-time applications. Consequently a great deal of research effort has been focused on the design of an efficient searching strategy and a discriminative measuring method for a good tracker. Under the probabilistic framework, we notice that intermediate measurements and the correlations among the multiple targets are valuable information for the generation of samples, which have not been fully utilized before. Therefore, the objective of this research is to exploit how to improve the searching efficiency by integrating these two factors into the sampling in several applications.

We first start with a single target tracking, and we propose to update the proposal distribution by dynamically incorporating the most recent measurements and generating particles sequentially, where the contextual confidence of the user on the measurement model is also involved. In addition, the matching template is divided into non-overlapping fragments, and by learning the background information, only a subset of the most discriminative target regions are dynamically selected to measure each particle, where the model update is easily embedded to handle fast appearance changes. The two parts are dynamically fused together such that the system is able to capture abrupt motions and produce a better localization of the moving target in an efficient way.

Then we extend our attention to the case of multiple targets, and we consider a special case where targets are highly correlated, demonstrating a common motion pattern with individual variations. We propose to update the sampling distribution by incorporating both the most recent observations and the correlation information. The correlation is either known a priori or learned from the previous tracking results. In this way, the observation of a single target is multiplexed statistically through mutual correlation for other targets, and the correlation serves as both a prior information to improve the efficiency and a constraint to prevent trackers from confusing or drifting. Experiments on both synthetic and real-world data verify the effectiveness of the new algorithm and demonstrate its superiority over existing methods.

Committee:

Yuan F. Zheng (Advisor); Jose B. Cruz, Jr. (Committee Member); Ashok Krishnamurthy (Committee Member); James M. Unger (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Particle filter; tracking; proposal distribution; measurement confidence; Haar; occlusion; MCMC

Penchikala, MadhuriANGIOTENSIN AT1 RECEPTOR BLOCKADE PROTECTS THE BRAIN FROM ISCHEMIC DAMAGE
Master of Science (MS), Wright State University, 2007, Pharmacology and Toxicology
Angiotensin (Ang) AT1 receptors are considered to play an important role in ischemic stroke via degenerative processes leading to cell death. Recent clinical and basic studies show that systemic blockade of Ang AT1 receptors reduces brain lesion in ischemic stroke. In this study we evaluated whether blockade of central Ang AT1 receptors protects the brain from ischemia and inflammation during ischemic stroke. Adult male C57BL/6 mice were divided into two groups for chronic intracerebroventricular (ICV) infusion of a selective Ang AT1 receptor antagonist, losartan (Los, n=18, 2 ug/hr) or isotonic saline (Con, n=20) using osmotic minipump. Twelve days post infusion, focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). The success of MCAO was verified by measurement of cerebral blood flow (CBF) using laser-Doppler flowmetry. Neurological deficits due to ischemic damage of neuronal cells were evaluated 24 hours after MCAO. Brains were removed 48 hrs after MCAO and the degree of damage due to ischemia was determined using triphenyltetrazolium chloride (TTC) staining. The expression of Ang AT1 receptors, matrix metalloproteinase-2 (MMP-2) and myeloperoxidase (MPO) was carried out using western blot analysis. Immunohistochemistry was performed to determine the inflammatory cell infiltration in control vs. losartan treated mice. Focal cerebral ischemia resulted in overexpression of Ang AT1 receptor ischemic hemisphere compared to non-ischemic hemisphere (27%, p<0.05) suggesting a role of Ang AT1 receptor in ischemia. We also found a significant increase in the expression of MPO and MMP-2 in ischemic vs. non-ischemic hemispheres. Pretreatment with losartan significantly improved neurological deficits and infarct volume compared to control mice (p < 0.05). Parelleling these effects on ischemia, losartan pretreatment also reduced (~50%) the reactive upregulation of MPO (P < 0.05) and inflammatory cells (neutrophils and macrophages, P < 0.01) in the ischemic area. These results support a role for Ang AT1 receptors in cerebral ischemia and inflammation produced by stroke.

Committee:

YANFANG CHEN (Advisor)

Subjects:

Health Sciences, Pharmacology

Keywords:

Stroke; angiotensin II; angiotensin type I (AT1) receptor; middle cerebral artery occlusion; ICV infusion; losartan

Keck, Mark A.Occlusion Recovery and Reasoning for 3D Surveillance
Doctor of Philosophy, The Ohio State University, 2009, Computer Science and Engineering

In this work we propose algorithms to learn the locations of static occlusions and reason about both static and dynamic occlusion scenarios in multi-camera scenes for 3D surveillance (e.g., reconstruction, tracking). We will show that this leads to a computer system which is able to more effectively track (follow) objects in video when they are obstructed from some of the views. Because of the nature of the application area, our algorithm willbe under the constraints of using few cameras (no more than 3) that are configured wide-baseline.

Our algorithm consists of a learning phase, where a 3D probabilistic model of occlusions is estimated per-voxel, per-view over time via an EM-style framework. In this framework, at each frame the visual hull of the foreground objects (people) is computed via a Markov Random Field that integrates the occlusion model. The model is then updated at each frame using this solution, providing an iterative process that can accurately estimate the occlusion model by accumulating temporal information and overcome the few-camera constraint. We demonstrate the application of such a model to a number of areas, including visual hull reconstruction, 3D tracking, and the reconstruction of the occluding structures themselves.

Committee:

James Davis, Ph.D. (Advisor); Rick Parent, Ph.D. (Committee Member); James Todd, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

Computer Vision; Occlusion Recovery, Tracking

Khare, VinodPrecise Image Registration and Occlusion Detection
Master of Science, The Ohio State University, 2011, Civil Engineering

Image registration and mosaicking is a fundamental problem in computer vision. The large number of approaches developed to achieve this end can be largely divided into two categories - direct methods and feature-based methods. Direct methods work by shifting or warping the images relative to each other and looking at how much the pixels agree. Feature based methods work by estimating parametric transformation between two images using point correspondences.

In this work, we extend the standard feature-based approach to multiple images and adopt the photogrammetric process to improve the accuracy of registration. In particular, we use a multi-head camera mount providing multiple non-overlapping images per time epoch and use multiple epochs, which increases the number of images to be considered during the estimation process. The existence of a dominant scene plane in 3-space, visible in all the images acquired from the multi-head platform formulated in a bundle block adjustment framework in the image space, provides precise registration between the images.

We also develop an appearance-based method for detecting potential occluders in the scene. Our method builds upon existing appearance-based approaches and extends it to multiple views.

Committee:

Alper Yilmaz, PhD (Advisor); Carolyn Merry, PhD (Committee Member); Li Rongxing, PhD (Committee Member)

Keywords:

Image Registration; Occlusion Detection; Multi-head Cameras; Bundle Adjustment

Tong, XinInteractive Visual Clutter Management in Scientific Visualization
Doctor of Philosophy, The Ohio State University, 2016, Computer Science and Engineering
Scientists visualize their data and interact with them on computers in order to thoroughly understand them. Nowadays, data become so large and complex that it is impossible to display the entire data on a single image. Scientific visualization often suffers from visual clutter problem because of high spacial resolution/dimension and temporal resolution. Interacting with the visualizations of large data, on the other hand, allows users to dynamically explore different parts of the data and gradually understand all information in the data. Information congestion and visual clutter exist in visualizations of different kinds of data, such as flow field data, tensor field data, and time-varying data. Occlusion presents a major challenge in visualizing 3D flow and tensor fields using streamlines. Displaying too many streamlines creates a dense visualization filled with occluded structures, but displaying too few streams risks losing important features. Glyph as a powerful multivariate visualization technique is used to visualize data through its visual channels. Placing large number of glyphs over the entire 3D space results in occlusion and visual clutter that make the visualization ineffective. To avoid the occlusion in streamline and glyph visualization, we propose a view-dependent interactive 3D lens that removes the occluding streamlines/glyphs by pulling the them aside through animations. High resolution simulations are capable of generating very large vector fields that are expensive to store and analyze. In addition, the noise and/or uncertainty contained in the data often affects the quality of visualization by producing visual clutter that interferes with both the interpretation and identification of important features. Instead, we can store the distributions of many vector orientations and visualize the distributions with 3D glyphs, which largely reduce visual clutter. Empowered by rapid advance of high performance computer architectures and software, it is now possible for scientists to perform high temporal resolution simulations with unprecedented accuracy. The large number of time steps makes it difficult to perform post analysis and visualization after the computation is completed. Instead of visualize all the time steps, users filter the original data that is too large to be all visualized and interactively pick the interesting parts of the data to display. To achieve this goal, we provide a time-varying data exploration system that allows users to pick the most salient time steps with Dynamic Time Warping (DTW) algorithm and then only visualize the data volumes corresponding to those time steps. We generalize three general strategies to manage visual clutter and demonstrate them using four visualization techniques. In the end of this dissertation, we present possible directions of future works that may inspire the readers to do more researches on visual clutter management for different data and applications.

Committee:

Han-Wei Shen (Advisor); Huamin Wang (Committee Member); Arnab Nandi (Committee Member)

Subjects:

Computer Engineering; Computer Science

Keywords:

visual clutter; view-dependent; focus-context; glyph-based visualization; virtual reality; touch screen; flow visualization; streamline; white matter tracts; deformation; occlusion management; time-varying data; vector field distribution; key time step

Collier, JeffExamining laser triangulation system performance using a software simulation
Master of Science (MS), Ohio University, 1998, Electrical Engineering & Computer Science (Engineering and Technology)

Examining laser triangulation system performance using a software simulation

Committee:

Joseph Nurre (Advisor)

Keywords:

laser triangulation system; CCD camera; Occlusion; software simulation

Ben-Amotz, RonEffects Of Intraperitoneal Bilirubin Administration On Infarct Area And Left Ventricular Function In A Rat Model Of Acute Coronary Occlusion
Master of Science, The Ohio State University, 2011, Veterinary Clinical Sciences
Bilirubin was considered to be a toxin that accumulates after catabolism of heme by the enzyme heme oxygenase. However, a mounting body of evidence suggests that bilirubin, at physiological (non-toxic) doses, is a powerful antioxidant and anti-atherosclerotic agent. Recent clinical studies have shown that human beings with mild hyperbilirubinemia (Gilbert Syndrome) are protected against coronary heart disease. The purpose of this study was to investigate whether administration of exogenous bilirubin to normal rats would convey similar protective effects in an experimental model of coronary ischemia. Our hypothesis was that bilirubin administration (20uM/kg, IP, 1 hour before injury) would decrease infarct area and preserve left ventricular function when compared to non-treated rats. Coronary ischemia was induced by temporary (30 min) ligation of the left anterior descending coronary artery in control rats (n=5) and in bilirubin treated rats (n=5), followed by a 1hour period of reperfusion. Left ventricular function was estimated non-invasively using echocardiographic measurements of fractional shortening and percent area shortening. Effects of anesthesia on cardiac function were controlled by using a sham group (n=5). There was a significant reduction of infarct size in the bilirubin treated group compared to the non-treated group (p<0.0067). Left ventricular systolic function decreased in both experimental groups after ischemia and reperfusion, although bilirubin seemingly provided a protective effect on fractional shortening during the period of ischemia (p=0.034). Based on these results, bilirubin supplementation appears to provide significant myocardial protection following ischemia in this rodent model. However, protective effects on left ventricular function were noted only during the period of ischemia.

Committee:

Christopher Adin (Advisor); John Bonagura, MS (Committee Member); Robert Hamlin, PhD (Committee Member)

Subjects:

Surgery; Veterinary Services

Keywords:

Ischemia; Reperfusion; Injury; Occlusion