In the modern society, mobile is gradually going to become all about video streaming. The main reasons of video growth are mobile devices such as smartphones and tablets which enable people to have access to videos they would like to watch at anywhere and anytime. However, due to the large video data size and intensive computation, video processing leads to a huge power consumption. Mobile system designers typically focus on hardware-level power optimization techniques without considering how hardware performance interfaces with viewer experience. In my research, I investigated how viewing context factors affect mobile viewing experience. Furthermore, a viewer-aware intelligent mobile video system was designed to optimize power efficiency automatically in real-time according to the viewing context and maintain the same viewing experience. Our research opened a door for developments of future viewer-aware mobile system design, accelerating low-cost mobile devices with longer battery life.

This master thesis deals with methodology for the possibility of properly evaluation the traffic situation by the driver based on the speed observation of a vehicle moving along the main road. It is outlined from the physicist aspect of the visual system of man and the vision of the man as a required element in the transport and traffic situation with variable speed.

Spatial-based attention is shown to vary in strength over short intervals of time. Whether object-based selection also has similar temporal variability is not known. Egly, Driver and Rafal (1994) demonstrated using 2-rectangle displays how both spatial and object-based selection engages in processing of a visual scene. In Experiment-1 using the 2-rectangle paradigm we measured temporal variability of target detection by presenting targets at a variable SOA. In Experiment-2, we used 4-squares to preclude any object-based selection and measured temporal variability in target detection at similar locations as in Experiment-1. We found target detection to be periodic in delta and theta hertz rhythm in both Experiment-1 and Experiment-2 upon comparing corresponding cue-valid and same-object locations. Similar spectral profiles across experiments indicate a split-spotlight of spatial attention that rhythmically monitors cue-valid and other invalid locations. Future experiments are needed to determine whether object-based selection is periodic in nature. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

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Yes / We investigated the role of the human right Supra-Marginal Gyrus (SMG) in the generation of learned eye movement sequences. Using MRI-guided transcranial magnetic stimulation (TMS) we disrupted neural activity in the SMG whilst human observers performed saccadic eye movements to multiple presentations of either predictable or random target sequences. For the predictable sequences we observed shorter saccadic latencies from the second presentation of the sequence. However, these anticipatory improvements in performance were significantly reduced when TMS was delivered to the right SMG during the inter-trial retention periods. No deficits were induced when TMS was delivered concurrently with the onset of the target visual stimuli. For the random version of the task, neither delivery of TMS to the SMG during the inter-trial period nor during the presentation of the target visual stimuli produced any deficit in performance that was significantly different from the no-TMS or control conditions. These findings demonstrate that neural activity within the right SMG is causally linked to the ability to perform short latency predictive saccades resulting from sequence learning. We conclude that neural activity in rSMG constitutes an instruction set with spatial and temporal directives that are retained and subsequently released for predictive motor planning and responses.

Yes / Where do the bottlenecks for information and attention lie when our visual system processes incoming stimuli? The human visual system encodes the incoming stimulus and transfers its contents into three major memory systems with increasing time scales, viz., sensory (or iconic) memory, visual short-term memory (VSTM), and long-term memory (LTM). It is commonly believed that the major bottleneck of information processing resides in VSTM. In contrast to this view, we show major bottlenecks for motion processing prior to VSTM. In the first experiment, we examined bottlenecks at the stimulus encoding stage through a partial-report technique by delivering the cue immediately at the end of the stimulus presentation. In the second experiment, we varied the cue delay to investigate sensory memory and VSTM. Performance decayed exponentially as a function of cue delay and we used the time-constant of the exponential-decay to demarcate sensory memory from VSTM. We then decomposed performance in terms of quality and quantity measures to analyze bottlenecks along these dimensions. In terms of the quality of information, two thirds to three quarters of the motion-processing bottleneck occurs in stimulus encoding rather than memory stages. In terms of the quantity of information, the motion-processing bottleneck is distributed, with the stimulus-encoding stage accounting for one third of the bottleneck. The bottleneck for the stimulus-encoding stage is dominated by the selection compared to the filtering function of attention. We also found that the filtering function of attention is operating mainly at the sensory memory stage in a specific manner, i.e., influencing only quantity and sparing quality. These results provide a novel and more complete understanding of information processing and storage bottlenecks for motion processing. / Supported by R01 EY018165 and P30 EY007551 from the National Institutes of Health (NIH).

Traumatic brain injury is a major health problem with much of its morbidity associated with traumatic axonal injury (TAI). To date, significant insight has been gained into the initiating pathogenesis of TAI. However, the specific anterograde and retrograde sequelae of TAI are poorly understood because the diffuse nature of TAI complicates data analysis. To overcome this limitation, we subjected transgenic mice expressing yellow fluorescent protein (YFP) within the visual system to central fluid percussion injury, and consistently generated diffuse TAI within the optic nerve that could easily be followed in the organized YFP positive fibers. We demonstrated progressive axonal swelling, disconnection and proximal and distal axonal dieback, with regression and reorganization of the proximal swellings, and the persistence of the distal disconnected and degenerating swellings. Antibodies targeting the C-terminus of amyloid precursor protein, a marker of TAI, mapped to the proximal axonal segments without distal targeting. Antibodies targeting microglia/macrophages, revealed activated microglia/ macrophages closely encompassing the distal disconnected, degenerating axonal segments at 7 - 28 days post injury, suggesting their role in the delayed axonal degeneration. In contrast, in the proximal reorganizing axonal segments, microglia/macrophages appeared less reactive with their processes paralleling preserved axonal profiles. Concomitant with these events, YFP fluorescence quenching also occurred, complicating data analysis. This quenching mapped to Texas-Red-conjugated-IgG immunoreactive loci, suggesting that blood–brain barrier disruption and its attendant edema participated in fluorescence quenching. This was confirmed through antibodies targeting endogenous YFP, which identified the retention of intact axons despite YFP fluorescent loss. Paralleling these events, TAI was not accompanied by retrograde retinal ganglion cell (RGC) death. Specifically, no TUNEL+ or cleaved caspase-3 immunoreactive RGCs were observed from 2 days to 3 months post-TBI. Further, Brn3a immunoreactive RGC quantification revealed no significant RGC loss. This RGC preservation was accompanied by the persistent phospho-c-Jun expression for up to 3 months post-TBI, a finding linked to neuronal survival and potential axonal repair. Parallel ultrastructural study again failed to identify RGC death. Collectively, this study provides unprecedented insight into the evolving pathobiology associated with TAI, and offers advantages for future studies focusing on its therapeutic management and neuronal reorganization.

Work title: The response of the visual system when driving a car in real conditions and in a simulator during a parallel motor task. Aims: To implement a laboratory measurement in a driving simulator and in real conditions during a parallel motor task. To track the response of the visual system during the task and to determine potential differences in the response of the visual system and in the speed in the simulator and in the real car environment. Methods: The laboratory measurement was realized in a driving simulator OCTAVIA II. The measurement in real conditions was realized in Škoda Octavia as well. The eye-tracking method was used to track the drivers` eyes. Results: In the simulator the more experienced driver managed to do the parallel motor task within a shorter period of time than the less experienced driver, lower frequency of looks at the radio during the tasks with the more experienced driver was not proved. There was not an evidence of more balanced speed during the drive with the more experienced driver in the simulator. On the average the driver spent shorter time doing the tasks in the real environment than in the simulator and the total number of looks at the radio was lower. The speed of the drive in the real environment was lower than the speed in the simulator. Key words:...

Os receptores glutamatérgicos metabotrópicos (mGluRs) estão envolvidos nos processos de plasticidade, neurodegeneração e neuroproteção. Avaliamos a expressão de mGluRs no sistema visual de ratos e pintos em diferentes tempos após enucleação ocular. Os animais foram avaliados pelo método de imuno-histoquímica, immunoblotting e RT-PCR, para detecção dos receptores mGluR1,2/3,5 e 7. Foi observado aumento da imunorreatividade (IR) de mGluR1, 5 e 7 no colículo superior, porém não foi observada diferença no núcleo geniculado lateral. Houve aumento na expressão protéica para mGluR1, 5 e 7 e aumento da expressão gênica para mGluR1,5 e 7; por outro lado, ocorreu uma diminuição de mGluR3. No TeO, foi observado aumento da IR para mGluR1 e 5 e diminuição para mGluR2/3. As análises de immunoblotting confirmaram o aumento observado de mGluR1 e diminuição de mGluR2/3. Os resultados indicam uma modulação diferencial na expressão gênica e protéica dos mGluRs, sugerindo a participação desses receptores em processos plásticos decorrentes de lesões no sistema visual adulto. / The metabotropic glutamate receptors (mGluRs) are involved in neuronal plasticity and neuroprotection. We analyzed the expression of mGluRs in the visual system of rats and chicks in several periods after ocular enucleation. The localization and expression of mGluR1, 5, 2/3 and 7 receptors were evaluated by standard immunoperoxidase, immunoblotting and real-time PCR protocols. The immunorreativity, protein and gene expression of mGluR1, 5 and 7 receptors in the superior colliculus showed an increase, whereas no changes were seen in the lateral geniculate nucleus. For mGluR3, gene expression was decreased. In the TeO, mGluR1 and 5 increased for all survival periods analyzed. Immunoblotting analyses confirmed the increases for mGluR1 and 5, decreases for mGluR2/3. These results indicate that the expression of mGluRs is regulated by the glutamatergic retinal input, and add data on a possible role of these receptors in neuroplasticity in adult animals.

Image quality measures are used to optimize image processing algorithms and evaluate their performances. The only reliable way to assess image quality is subjective evaluation by human observers, where the mean value of their scores is used as the quality measure. This is known as mean opinion score (MOS). In addition to this measure there are various objective (quantitative) measures. Most widely used quantitative measures are: mean squared error (MSE), peak signal to noise ratio (PSNR) and signal to noise ratio (SNR). Since these simple measures do not always produce results that are in agreement with subjective evaluation, many other quality measures have been proposed. They are mostly various modifications of MSE, which try to take into account some properties of human visual system (HVS) such as nonlinear character of brightness perception, contrast sensitivity function (CSF) and texture masking. In these approaches quality measure is computed as MSE of input image intensities or frequency domain coefficients obtained after some transform (DFT, DCT etc.), weighted by some coefficients which account for the mentioned properties of HVS. These measures have some advantages over MSE, but their ability to predict image quality is still limited. A different approach is presented here. Quality measure proposed here uses simple model of HVS, which has one user-defined parameter, whose value depends on the reference image. This quality measure is based on the average value of locally computed correlation coefficients. This takes into account structural similarity between original and distorted images, which cannot be measured by MSE or any kind of weighted MSE. The proposed measure also differentiates between random and signal dependant distortion, because these two have different effect on human observer. This is achieved by computing the average correlation coefficient between reference image and error image. Performance of the proposed quality measure is illustrated by examples involving images with different types of degradation.