Thèses sur le sujet « Visual area »
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1
Hudson, Andrew E. « Attentional modulation in primate visual area V4 / ». Access full-text from WCMC:, 2007. http://proquest.umi.com/pqdweb?did=1296098321&sid=10&Fmt=2&clientId=8424&RQT=309&VName=PQD.
Texte intégral
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Cadieu, Charles Fredrick. « Modeling shape representation in visual cortex area V4 ». Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30367.
Texte intégralRésumé :
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 85-89).
Visual processing in biological systems is classically described as a hierarchy of increasingly sophisticated representations, originating in primary visual cortex (V1), progressing through intermediate area V4, and ascending to inferotemporal cortex. The computational mechanisms that produce representations in intermediate area V4 have remained a mystery. In this thesis I show that the standard model, a quantitative model which extends the classical description of visual processing, provides a computational mechanism capable of reproducing and predicting the responses of neurons in area V4 with a translation invariant combination of V1 responses. Using techniques I have developed, model neurons accurately predict the responses of 8 V4 neurons to within-class stimuli, such as closed contours and gratings, and achieve an average correlation coefficient of 0.77 between predicted responses and measured V4 responses. Furthermore, model neurons fit to a V4 neuron's grating stimulus response, can qualitatively predict the V4 neuron's 2-spot reverse correlation map. These results successfully demonstrate the first attempt to bridge V1 and V4 experimental data, by describing how representation in V4 could emerge from the nonlinear combination of V1 neural responses.
by Charles Fredrick Cadieu.
M.Eng.
3
Mansouri, Sina Sharif. « On Visual Area Coverage Using Micro Aerial Vehicles ». Licentiate thesis, Luleå tekniska universitet, Signaler och system, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-68666.
Texte intégralRésumé :
The aim of this Licentiate is to advance the field of cooperative visual coverage path planners for multiple Micro Aerial Vehicles (MAVs), while aiming for their real life adoption towards the tasks of aerial infrastructure inspection. The fields that will be addressed are focusing in: a) the collaborative perception of the environment, b) the collaborative visual inspection, and c) the optimization of the aerial missions based on the remaining flying battery, camera constraints, coverage constraints and other real life mission induced constraints. Towards this envisioned aim, this Licentiate will present the following main theoretical contributions: a) centralized and distributed Model Predictive Control (MPC) schemes for the cooperative motion control of MAVs focusing in the establishing of a formation control architecture to enable a dynamic visual sensor from monocular cameras towards a reconfigurable environmental perception, b) revisiting the Cooperative Coverage Path Planning (C-CPP) problem for the inspection of complex infrastructures, c) developing a holistic approach to the problems of 2-D area coverage with MAVs for polygon areas, while considering the camera footprint, and d) designing of a scheme to estimate the Remaining Useful Life (RUL) of the battery during a flight mission, a fact that directly effects the flying capabilities of the MAVs. The theoretical contributions of this thesis have been extensively evaluated in simulation and real life large scale field trials, a direction that adds another contribution of the suggested framework towards the massive insertion of the aerial platforms as aerial tools in the close future. In the first part of this Licentiate, the vision, motivation, open challenges, contributions, and future works are discussed, while in the second part the full articles connected to the presented contributions in this Licentiate are presented in the annex.
4
Duncan, Hazel Annette. « Beyond shadowplay : the body and the visual ». Monash University, Centre for Comparative Literature and Cultural Studies, 2004. http://arrow.monash.edu.au/hdl/1959.1/5216.
Texte intégral
5
King, Li-Wei. « Selectivity and development of the visual word form area ». Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/79184.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, February 2013.Cataloged from PDF version of thesis. "February 2013."
Includes bibliographical references (p. 95-113).
An area of left occipitotemporal cortex commonly referred to as the visual word form area (VWFA), has consistently been shown to activate during the processing of written language. However, the exact nature of the region's selectivity is still under debate. In this thesis, I explore the selectivity of the visual word form area at three different levels. First, I examine whether the VWFA differentiates between letter strings of different lexicality and pronounceability and argue that the VWFA's selectivity is greatly influenced by attention. Second, I explore the developmental course of mirror discrimination in the VWFA, and show that children do not display adult-like mirror discrimination of letters even into early adolescence. Finally, I look at the developmental course of VWFA selectivity for words compared to nonlinguistic visual stimuli. While children have adult-like activation patterns when words are compared to a low-level visual control, they show less specialization compared to adults when objects are used as a control.
by Li-Wei King.
Ph.D.
6
Chen, Zhuling M. Eng Massachusetts Institute of Technology. « Production system improvement : floor area reduction and visual management ». Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78157.
Texte intégralRésumé :
Thesis (M. Eng. in Manufacturing)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 69-70).
This thesis suggests on the development process of a new layout design and visual management tools to improve the efficiency of a production line in a medical device company. Lean production philosophy and common lean techniques were adopted as a guideline in this project. A new layout design was proposed to utilize less manufacturing space while maintaining or improving the current production rate. A thorough study of the current system was conducted and preliminary analysis on the current system efficiency was evaluated. Design concepts were generated based on major reduction opportunities, namely removal of non-production areas on the floor, a point of use inventory system, consolidation of equipment and benches, new bench configuration. The final layout design reduced 479 ft 2 from the original layout with the same production rate. Visual management tools were developed after identifying key performance indicators for the production line. The visual management tools presented important data in a comprehensive way, facilitated communication among the production team and management team and empowered production associates in making continuous improvement on the floor. Key Words: Lean Manufacturing, Floor Area Reduction, Visual Management, Key Performance Indicators, System Efficiency
by Zhuling Chen.
M.Eng.in Manufacturing
7
Zaharia, Andrew D. « Neural computation of visual motion in macaque area MT ». Thesis, New York University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10192285.
Texte intégralRésumé :
How does the visual system determine the direction and speed of moving objects? In the primate brain, visual motion is processed at several stages. Neurons in primary visual cortex (V1), filter incoming signals to extract the motion of oriented edges at a fine spatial scale. V1 neurons send these measurements to the extrastriate visual area MT, where neurons are selective for direction and speed in a manner that is invariant to simple or complex patterns. Previous theoretical work proposed that MT neurons achieve selectivity to pattern motion by combining V1 inputs consistent with a common velocity. Here, we performed two sets of experiments to test this hypothesis. In the first experiment, we recorded single-unit V1 and MT responses to drifting sinusoidal gratings and plaids (two gratings superimposed). These stimuli either had jointly varying direction and drift rate (consistent with a constant velocity) or independently varying direction and drift rate. In the second experiment, we presented arbitrary, randomly chosen combinations of gratings in rapid succession, to sample as widely as possible the space of stimuli that could excite or suppress neural responses. Responses to single gratings alone were insufficient to uniquely identify the organization of MT selectivity. To account for MT responses to both simple and compound stimuli, we developed new versions of an existing cascaded linear-nonlinear model in which each MT neuron pools inputs from V1. We fit these models to our data. By comparing the performance of the different model variants and examining their parameters that best accounted for the data, we showed that MT responses are best described when selectivity is organized along a common velocity. This confirms previous predictions that MT neurons are selective for the arbitrary motion of objects, independent of object shape or texture. We explore new model variants of MT computation that capture this behavior. These studies show that in order to characterize sensory computation, stimuli must be complex enough to engage the nonlinear aspects of neural selectivity. By exploring different linear-nonlinear model architectures, we identified the essential components of MT computation. Together, these provide an effective framework for characterizing changes in selectivity between connected sensory areas. Supplementary materials: figures 3.4(a-e), 3.10(a-e), and 3.14(a-e) are rendered as movies.
8
Downes, Sarah. « Reading Jean Rhys : empire, modernism and the politics of the visual ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206736.
Texte intégralRésumé :
This thesis considers the relationship between literary modernism and visual culture in the work of Caribbean modernist Jean Rhys. Through analysis of a range of visual modes—theatre, fashion, visual art, cinema and exhibition culture—it examines the racialised sexual politics of Rhys’s modernist aesthetics, as represented in her texts of the 1920s—30s.
I read Rhys’s four interwar novels—Quartet (1928), After Leaving Mr Mackenzie (1930), Voyage in the Dark (1934) and Good Morning, Midnight (1939)—in the context of contemporary visual practices and the politics of empire. Rhys’s descriptions of artistic practices, acts of viewing and interpreting art, and the identification of her protagonists as both objects and consumers of art are a crucial aspect of her anti-colonial feminism. The politics of vision and of empire are always intertwined for Rhys. Chapter One studies theatrical spectacle and everyday performances of the self. Chapter Two moves to the fashioning of female identities and sartorial constructions of Englishness. Chapter Three turns to Rhys’s use of ekphrasis to question representational structures as they exist in the modernist, primitivist art context. Chapter Four reads Rhys and cinema, focusing on divided or fractured subjectivities as relayed through allusions to distorted mirrors. This conveys Rhys’s powerful evocation of themes of alienation and dislocation. I conclude by analysing what ‘exhibition’ means for those occupying both subject and object visual positions within the imperial metropolis. Analysis is supported by readings of unpublished short stories, letters and poems, works that are relatively absent from current Rhys scholarship.
The conjunction of revolutions in the visual arts and the destabilization of the empire in the modernist period provides clear space for investigation into the creation of new ways of seeing that provided a degree of visual agency for those deemed incapable of aesthetic production. Crucial to this is Rhys’s own Creolité. Situated within and outside of European visual subjectivity, Rhys’s work becomes vital to any study of social acts of seeing, in terms of individual subjectivity and within the wider systems of vision produced through the arts.published_or_final_version
English
Doctoral
Doctor of Philosophy
9
Crook, J. M. « A neurophysiological investigation of the feline extrastriate visual cortex (area 18) using oriented and textured stimuli : A comparison with area 17 ». Thesis, Keele University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379422.
Texte intégral
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Biro, Dora. « The role of visual landmarks in the homing pigeon's familiar area map ». Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249515.
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Zhao, Ruilin 1972. « Functional analysis of middle temporal visual area and its associated behavior ». Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8084.
Texte intégralRésumé :
Thesis (Ph. D.)--Harvard--Massachusetts Institute of Technology Division of Health Sciences and Technology, 2002.Includes bibliographical references (leaves 106-120).
Our lab's long-term goal is to elucidate the circuitry of the visual cortex, to develop quantitative computational models of neuronal function in the visual cortex, and to establish how these models may relate to visual perception and visually guided behavior. Central to this goal is the analysis of functional architecture, which is crucial to an understanding of how the brain works. In my thesis research, I applied behavioral and microstimulation techniques to demonstrate the causal connections between neural activity and behavior. Understanding these relationships is one of the fundamental issues needed to be addressed in Neurobiology. Specifically, I focused on the functional analysis of the middle temporal visual area (MT) and the behavior associated with it. MT is an extrastriate area that is primarily involved in visual motion processing. A very important function within MT is a segregation of center-surround interactions which plays a critical role in processing visual motion cues. There are two types of motion center-surround interactions in MT neurons: surrounds may reinforce (at wide-field sites) or suppress (at local-motion sites) the centers' directional responses. They are important in representing the initial stages of a functional segregation between wide-field and local-contrast motion processing. To further study the computational model used by the brain to readout sensory information, I conducted microstimulation experiments in MT by changing stimulation amplitudes (from 10/LA to 160tA) and frequencies (from 25Hz to 500Hz). Microstimulation can introduce an additional velocity signal into MT and the pursuit and saccadic systems usually compute a vector average of the visually evoked and microstimulation-induced velocity signals.
(cont.) Increasing either amplitude or frequency generally increases the relative weight of the electrical velocity signal,' with the effects of amplitude being slightly more prominent. In addition, applying higher current fre-quencies appears to preserve the directionality of microstimulation better than does applying higher current amplitudes. With increasing frequencies, the magnitude of the electrical velocity signal either increased or remained constant, while its direction remained consistent. In contrast, increasing current amplitude tended to decrease the magnitude of the signal and increased its variability in direction. This finding is consistent with the idea that large current amplitudes, which presumably activate many MT columns signaling different directions, introduce noise into the behavior. My preliminary results have demonstrated that microstimulation in MT can also introduce an additional positional signal into the saccade system and that this electrical signal is combined with the visually evoked signal through a vector summation mechanism. The direction of this electrical signal is highly correlated with the position of the receptive field relative to the fixation point. To test the notion that the center-surround properties of MT neurons may be important for signaling the relative motion between object and background, we conducted behavioral experiments by using real background motion to simulate the microstimulation experiments at wide-field sites ...
by Ruilin Zhao.
Ph.D.
12
Tanaka, Tomohiro. « Visual response of neurons in the lateral intraparietal area and saccadic reaction time during a visual detection task ». Kyoto University, 2013. http://hdl.handle.net/2433/179343.
Texte intégral
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Berman, Daniel. « Representations of Spatial Frequency, Depth, and Higher-level Image Content in Human Visual Cortex ». The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1542184547546769.
Texte intégral
14
Price, D. J. « The organisation and development of area 18 of the cat's visual cortex ». Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355793.
Texte intégral
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Ghadooshahy, Azriel (Azriel Sion). « A prefrontal source of visual target enhancement in the macaque area V4 ». Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/114077.
Texte intégralRésumé :
Thesis: S.M. in Neuroscience, Massachusetts Institute of Technology, Department of Brain and Cognitive Sciences, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (page 16).
The ventral pre-arcuate area (VPA) in the primate prefrontal cortex has recently been found to play an important role in feature-based selection of visual targets in the context of a naturalistic free-gaze visual search task. While VPA neuronal activation was found to be necessary for behavioral performance as well as target selection in the FEF, its role in the broader context of the visual system remains to be addressed. To this end, we have interrogated the role of the VPA in mediating the effects of feature attention in the macaque visual area V4 by recording in V4 with and without muscimol inactivation in the VPA. We report here that neuronal activation in the VPA is necessary for firing rate increases related to target selection in V4. KEYWORDS: feature attention, visual search, muscimol, neurophysiology
by Azriel Ghadooshahy.
S.M. in Neuroscience
16
Abel, Paul Lawrence. « The pattern of anatomical connections in visual area V2 of Macaque monkey / ». Thesis, Connect to this title online ; UW restricted, 1997. http://hdl.handle.net/1773/9079.
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17
Solomon, Selina Sharmalar. « Population signals in the middle temporal (MT) area of marmoset visual cortex ». Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/12685.
Texte intégralRésumé :
In primates, including humans, the perception of motion and the control of eye movements depend on the population activity of neurons in the middle temporal (MT) area of the visual cortex. Much is known about the responses of individual neurons in area MT, but it is unclear how neurons work together to provide motion analysis. In the work of this thesis, I use electrophysiological recordings from area MT of a New World monkey, the common marmoset (Callithrix jacchus), to provide knowledge of the spatial and temporal structure of spiking activity and local field potentials (LFP). I first establish that the functional properties of neurons in area MT of the marmoset are similar to those in the major primate model of visual processing, the macaque monkey. I then use multi-electrode arrays to examine co-variability in spiking activity and LFP during rest, and during presentation of visual stimuli. There are three main findings of this thesis. First, correlated variability is affected by the presentation of a visual stimulus, and its structure depends on whether the visual stimulus is a dot field or a grating. Second, correlated variability has local and global components; the local component is largely independent of the type of visual stimulus used, but the global component depends on whether the stimulus is a dot field or a grating. Third, the distinct structures of spiking co-variability observed during presentations of dot fields and gratings do not reflect distinct local mechanisms, but instead distinct global interactions between local mechanisms that are similarly employed during presentation of a stimulus. Together, these results suggest that visual processing in area MT involves stable neural circuitry that is local, and global neural circuitry that is dynamically modulated by a visual stimulus.
18
Di, Silvestro Lorenzo Paolo. « Data Mining and Visual Analytics Techniques ». Doctoral thesis, Università di Catania, 2014. http://hdl.handle.net/10761/1559.
Texte intégralRésumé :
With the beginning of the Information Age and the following spread of the information overload phenomenon, it has been mandatory to develop a means to simply explore, analyze and summarize large quantity of data. To achieve this purposes a data mining techniques and information visualization methods are used since decades.
In the last years a new research field is gaining importance: Visual Analytics, an outgrowth of the fields of scientific and information visualization but includes technologies from many other fields, including knowledge management, statistical analysis, cognitive science and decision science. In this dissertation the combined effort of the mentioned research fields will be analyzed, pointing out different way to combine them following the best practice according to several application cases.
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Santarcangelo, Vito. « Visual Behavior Analysis in Retail Scenario ». Doctoral thesis, Università di Catania, 2018. http://hdl.handle.net/10761/4135.
Texte intégralRésumé :
The retail world is today highly competitive and has seen its logics completely revolutionized by the introduction of e-commerce that have prompted a reaction from the retail market, requiring greater attention to the consumer. We therefore moved from the world of traditional marketing (generic flyer) to that of 1to1 marketing (specific attention to the customer, profiling and personalization of the assortment offer). In this context the need arises to introduce innovative tools that can allow the physical sales spaces to be kept competitive, interacting more with the customer in order to create a more relevant commercial proposal. As a consequence, the computer vision represented one of the possible means to carry out the behavioral analysis of the consumer useful for dynamically adapting the assortment proposal.
DOOH (Digital Out Of Home) in its most widespread form of interactive point-of sale kiosks is one of the best tools to get in touch with the customer, create a synergy with him, listen to his needs in order to improve the offer, the level of service and therefore customer satisfaction. Next to DOOH, it is necessary to introduce further and time-continuous monitoring tools, which map the entire customer's shopping experience into the point of sale. For this purpose the egocentric vision is introduced through the use of cam narratives on board the trolleys, which allow a timely story of the consumer, called Visual Market Basket Analysis (evolution of Market Basket Analysis), which generates process functional alerts to the improvement of
the service offered. The story of these approaches is provided in this PhD thesis, which tells the three-year course carried out, its experiments and possible future developments.
This study has been conducted thanks to the support of Centro Studi S.r.l., a sister company of a privately owned consumer goods distribution company called Orizzonti Holding Group, located in southern Italy. The study has been implemented through an industrial application approach, in a real context (Futura Supermarkets). Consequently, the PhD thesis has considered the typical difficulties of a challenging environment, starting from the creation and acquisition of a dataset to the integration of the approach in the current business processes.
20
Cavallet, Mikael. « Distribuição da atenção visual em áreas não adjacentes do campo visual ». Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/59/59134/tde-17112011-154944/.
Texte intégralRésumé :
A atenção visual é um conjunto de processos que permite processar preferencialmente uma informação visual em um dado momento. Muitos modelos de atenção visual propõem que a atenção pode ser destinada e focalizada a uma única localização no espaço por vez quando dicas espaciais são usadas para orientar esse deslocamento. Porém, diferentes estudos têm encontrado evidências de que em circunstâncias apropriadas, a atenção pode ser destinada a áreas não adjacentes do campo visual. O objetivo deste estudo foi investigar a distribuição da atenção por estas áreas quando o tamanho e a localização de dicas espaciais periféricas foram manipulados. Os resultados sugerem que a atenção visual pode ser destinada a mais de uma localização ao mesmo tempo como um gradiente com picos de processamento, mas que o tamanho das áreas indicadas não deve ser determinante para isso ocorrer. Os resultados indicam também que a habilidade para dividir a atenção pode depender da localização em que os eventos ocorrem em relação aos lados do campo visual. Eventos que ocorrem em lados opostos têm uma chance maior de serem beneficiados por focos independentes de atenção, enquanto eventos que ocorrem do mesmo lado do campo visual parecem ter mais chance de serem processados por um foco único de atenção, mas essa diferença parece ser relativa do que absoluta. Este estudo traz também contribuições para o entendimento do processo de focalização quando diferentes tarefas são solicitadas, revelando que o ajuste da atenção ao tamanho de uma área indicada é mais facilmente verificado em tarefas que requerem a detecção rápida de um alvo do que quando julgamentos de ordem temporal são solicitados.Visual attention is a set of processes which permits a preferential processing of visual information in a given moment. Several models of visual attention propose that attention might be allocated and focused in only one location by time when spatial cues are used to orient this displacement. However, different studies have been finding evidences that in appropriate circumstances, attention can be deployed to non-adjacent areas of the visual field. The main objective of the present study was to investigate the distribution of attention on these areas when the size and the localization of peripheral spatial cues were manipulated. The results suggest that visual attention can be deployed to more than one location simultaneously as a gradient with peaks in processing quality. The results also indicate that the ability to divide attention might depend on the localization in which the events occur in relation to each hemifield. Events that occur in different hemifields have more chance to take advantage of independent focus of attention while events that happen on the same hemifield have more chance to be processed by a single attentional focus but that this difference seems to be relative than absolute. This study have also contributions for the understanding of the focalization process when different tasks are requested revealing that the adjustment of the attentional focus to the size of a cued area is more easily verified in tasks that require fast detection of an target than when temporal order judgments are requested.
21
Das, Nibedita. « Critical analysis of Shyambazar traffic intersection area, Kolkata : A study of visual appropriateness ». Kansas State University, 2006. http://hdl.handle.net/2097/145.
Texte intégralRésumé :
Master of Regional and Community PlanningDepartment of Landscape Architecture/Regional and Community Planning
Ray B. Weisenburger
This research explores the challenges related to the visual image of a city situated in a developing country. Originated as the colonial capital of British India, Kolkata faces new urban challenges in the post colonial world. This report intends to answer questions of imageability of the city as relevant to the Third World countries. Empathizing on the issues of scarcity of land, traffic congestion, accumulation of the urban poor, inadequacies in infrastructure and the organic expansion of fluid city boundaries under the neo-ideological globalization and liberal economic policies – Kolkata faces a host of urban problems. Imageability of the city usually tries to define the positive image of a city. The question here is, should the notions of imageability be confined to cities that inherently have succeeded in maintaining an appealing public image or should it be applied to the potential qualities of visual appropriateness to cities that have historically remained unattractive? This research intends to explore the visual quality of an area surrounding the five point intersection at Shyambazar, Kolkata, India. This study will be based on a number of observations and the different visual analysis techniques applicable in critically analyzing the visual conditions of an urban street pattern of a megacity in India. The main objective of this study is to find an appropriate visual quality for Kolkata, a megacity in the tropics – considering various related factors like – historical significance, demographic trends, geographical and climatological influences, transportation pattern, existing land use, socio-economic structure and inherent or associated urban problems of planning in developing nations.
22
Courtney, Jon R. « Examining memory for area and distance untangling the relationship between memory psychophysics and boundary extension / ». Fort Worth, Tex. : Texas Christian University, 2006. http://etd.tcu.edu/etdfiles/available/etd-07262006-140632/unrestricted/courtney.pdf.
Texte intégral
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Smith, Jackson. « The link between neural activity in area MT of visual cortex and motion perception ». Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110544.
Texte intégralRésumé :
The transformation from action potentials to perception can only beunderstood by first explaining how the brain uses sensory neural responses todrive perceptual behaviour. It is currently unknown to what extent this is achievedby bottom-up or top-down processes. In a bottom-up model, sensory neuralactivity has a direct impact upon perceptual performance. But in a top-downmodel, the subject's high-order mental state determines perceptual performance,while also feeding signals back down to sensory neurones. The validity of eithermodel is complicated by the prediction that the link between sensory neurones andperceptual behaviour is critically affected by the level of correlation betweensensory neural signals.In this thesis, three main questions are asked to better understand how thebrain connects sensory neural activity to perceptual behaviour. (1) Can a bottom-up model explain the detection of visual motion? (2) Do visual neurones receivetop-down signals that predict motion detection performance? (3) Is the connectionof visual neurones to motion detection related to the correlations between visualneural signals?To answer these questions, we recorded neural activity from the middletemporal area (MT i.e. V5) of visual cortex – while monkey subjects performed amotion-detection task. The experiment was designed to separate bottom-up fromtop-down activity in time, by using a brief and unpredictable motion signal tocontrol when the neurones were informative. Separation was further achieved bycomparing the bottom-up versus top-down spectral components of local fieldpotentials that were recorded alongside the spiking responses. The potentialsources of neural correlation were limited by choosing pairs of neurones withreceptive fields that did not overlap, and by recording each neurone on a separateelectrode 1–2 mm from its partner. Crucially, the motion stimuli were tailored tomaximise the contribution of each neurone to the subject's detection performance.There were three major observations. (1) The link between MT spikingresponses and the subject's detection performance was well accounted for by abottom-up model. (2) Top-down signals arrived in MT, but after the local, bottom-up response to the motion signal. (3) The correlation between a pair of MTneurones was dynamic, and varied with the pair's link to motion detectionperformance. Altogether, the results presented in this thesis favour a bottom-upconnection between sensory neurones and perceptual behaviour, but suggest adynamic interaction between sensory responses and top-down signals.La transformation des potentiels d'action en perception ne peut êtrecomprise qu'en expliquant d'abord la façon dont le cerveau utilise les réponsesneurosensorielles pour dicter le comportement perceptif. À l'heure actuelle, nousignorons dans quelle mesure cela est accompli par les processus ascendant etdescendant. Dans un modèle ascendant, l'activité neurosensorielle a une incidencedirecte sur la perception. Cependant, dans un modèle descendant, l'état mentald'ordre supérieur du sujet détermine la perception, tout en alimentant également leretour des signaux vers les neurones sensoriels. La validité de chaque modèle estcomplexifiée par la prédiction que le lien entre les neurones sensoriels et lecomportement perceptif est fortement influencé par le niveau de corrélation entreles signaux neurosensoriels.Dans la présente thèse, trois questions importantes sont posées afin demieux comprendre la façon dont le cerveau relie l'activité neurosensorielle aucomportement perceptif. (1) Un modèle ascendant peut-il expliquer la détectiond'un mouvement visuel? (2) Les neurones visuels reçoivent-ils des signauxdescendants qui prédisent la détection du mouvement? (3) La connexion entre lesneurones visuels et la détection du mouvement est-elle liée aux corrélations entreles signaux neurovisuels?Pour répondre à ces questions, nous avons enregistré l'activité neuronalede la région temporale médiane (MT i.e. V5) du cortex visuel pendant que lessujets simiens effectuaient un exercice de détection du mouvement. L'expériencea été conçue afin de distinguer l'activité ascendante de l'activité descendante dansle temps au moyen d'un signal mobile bref et imprévisible pour capter le momentoù les neurones échangeaient de l'information. On a poussé la distinction encomparant les composantes spectrales, ascendante et descendante, des potentielsde champs locaux qui ont été enregistrées pendant les réponses de décharge. Lessources potentielles de corrélation neurale ont été limitées en choisissant despaires de neurones ayant des champs réceptifs qui ne se chevauchaient pas, et enenregistrant le signal de chaque neurone à l'aide d'une électrode distincte située à1 à 2 mm de sa contrepartie. Il a été tout particulièrement important d'adapter lesstimuli mobiles pour maximiser la contribution de chaque neurone à la détectiondu sujet.Trois observations majeures ont été faites. (1) Le lien entre les réponses dedécharge de l'aire MT et la détection du sujet est bien expliqué par un modèleascendant. (2) Les signaux descendants sont arrivés dans l'aire MT, mais après laréponse ascendante locale au signal mobile. (3) La corrélation entre une paire deneurones de l'aire MT et le lien de la paire par rapport à la détection dumouvement a été dynamique et variée. Somme toute, les résultats présentés danscette thèse favorisent une connexion ascendante entre les neurones sensoriels et lecomportement perceptif, mais suggèrent une interaction dynamique entre lesréponses sensorielles et les signaux descendants.
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Dambacher, Michael, Martin Rolfs, Kristin Göllner, Reinhold Kliegl et Arthur M. Jacobs. « Event-related potentials reveal rapid verification of predicted visual input ». Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2010/4495/.
Texte intégralRésumé :
Human information processing depends critically on continuous predictions about upcoming events, but the temporal convergence of expectancy-based top-down and input-driven bottom-up streams is poorly understood. We show that, during reading, event-related potentials differ between exposure to highly predictable and unpredictable words no later than 90 ms after visual input. This result suggests an extremely rapid comparison of expected and incoming visual
information and gives an upper temporal bound for theories of top-down and bottom-up interactions in object recognition.
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Oliveira, Juliana Rigotti de. « Accessibility and pedestrian mobility oith phisical disabilities and visual area in urban Tauabté city (SP) ». Universidade de Taubaté, 2015. http://www.bdtd.unitau.br/tedesimplificado/tde_busca/arquivo.php?codArquivo=799.
Texte intégralRésumé :
The increase in population, economic development and ease in acquisition of vehicles for individual transportation in Brazil (car and motorcycle) in recent decades have resulted in targeted policies and projects for the road system and the mobility of motor vehicles, with making the pedestrian disabled or not, suits existing environment. Policies and projects aimed at accessibility and mobility of people with disabilities (PCD) are recent and are deployed in some Brazilian cities. From this premise, this paper aims to examine and discuss measures aimed at accessibility and mobility pedestrian sidewalks in the urban area of the city of Taubaté. Field research was conducted with a quantitative approach, and exploratory mode, probabilistic and accessibility. Participatory actors are within the classes of disabled and visually impaired, the sample consisted of 31 shares and the applied instrument for data analysis was the analysis of Pearson (r). The work had as a basic reference the existing literature on the subject, as well as field research. The results show that the difficulties of accessibility and mobility of people with disabilities occur due to the current structure of sidewalks as wide, obstacles, physical barriers, signaling absence and projects targeted physical and visual PCD.O aumento da população, o desenvolvimento econômico e a facilidade na aquisição de veículos para o transporte individual no Brasil (automóvel e motocicleta) nas últimas décadas resultaram em políticas e projetos voltadas para o sistema viário e a mobilidade dos veículos motorizados, fazendo com que o pedestre com deficiência ou não, se adapte ao ambiente existente. As políticas e projetos voltados para a acessibilidade e mobilidade das pessoas com deficiência (PCD) são recentes e estão implantadas em algumas cidades brasileiras. Ao partir dessa premissa, esta pesquisa tem o objetivo de analisar medidas direcionada a acessibilidade e mobilidade do pedestre nas calçadas na área urbana da cidade de Taubaté localizada no Estado de São Paulo. Foi realizado pesquisa de campo, com abordagem quantitativa, de modo exploratório, probabilístico e por acessibilidade. Os atores participativos, estão dentro das classes dos deficientes físicos e deficientes visuais, a amostra foi composta de 31 participantes. O instrumento aplicado foi um questionário e para análise dos dados foi aplicado a análise de Correlação de Pearson (R). O trabalho desenvolvido teve como referência básica a literatura existente sobre o assunto, assim como na pesquisa de campo. Os resultados obtidos demonstram que as dificuldades de acessibilidade e mobilidade das pessoas com deficiência, ocorrem devido a estrutura atual das calçadas, como largura, obstáculos, barreiras físicas e ausência de sinalização. Conclui-se que o Poder Público precisa adotar um conjunto de medidas, como práticas aplicadas com sucesso em outras cidades e países, por meio de planejamento a longo prazo e elaboração de políticas públicas que respeite as características e limitações das PCD física e visual.
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Hunter, Matthew W. « Liberation in White and Black : The American Visual Culture of Two Philadelphia-area Episcopal Churches ». Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/108346.
Texte intégralRésumé :
ReligionPh.D.
Liberation in White and Black studies, respectively, Washington Memorial Chapel (WMC) and The Church of the Advocate (COA), which are two Episcopal parishes in the Diocese of Pennsylvania. This dissertation investigates the ways that the visual culture of these spaces represents and affects the religious, racial and national self-understanding of these churches and their ongoing operations by offering particular and opposing narrative interpretations of American history. These "sacred spaces" visually describe the United States (implicitly and explicitly) in terms of race and violence in narratives that set them in fundamental opposition to each other, and set a trajectory for each parishes' life that has determined a great deal of its activities over time. I develop this thesis by situating each congregation and its development in the context of the entire history of both the Episcopal Church and Philadelphia as related to race, violence and patriotism. WMC is what historian of religions scholar Jonathan Z. Smith calls a "locative" space and tries to persuade all Americans to patriotically covenant with images of heroic "White" freedom struggle. COA is what Smith calls a "utopian" space and tries to compel its visitors to covenant with a subversive critique of the United States in terms of the parallels between biblical Israel and the African American freedom struggle. My analysis draws especially on the theoretical work of Pierre Bourdieu and David Morgan. A major focus of Pierre Bourdieu's work in both Language and Symbolic Power, and The Logic of Practice is the power of group-making. Group-creating power is often exercised through representations that create a seemingly objective sense of group identity and a social world that is perceived as "natural." David Morgan writes that religious visual culture functions as this sort of political practice through the organization of memory among those who are drawn to "covenant" with images. The Introduction of my dissertation lays out the theoretical approaches informing the visual culture analysis of these Episcopal Churches and raises the significant questions. Three main chapters provide: 1) an historical background of patriotism, race and violence in the Episcopal Church and in Philadelphia in particular, and 2-3) a thorough analysis of the history and visual culture of each space in context. A great deal of my analysis will be interpretive "readings" of the visual culture of the aforementioned churches in their larger contexts to explain how the visual culture represents social classifications to affect the constituents religious, racial and national self-understanding, and their ongoing operations by offering particular and opposing narrative interpretations of American history. The project concludes by summarizing the ways that the analysis of these spaces explicates the thesis with thoughts about the implications for the disciplines involved and further research.
Temple University--Theses
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Kogan, Cary. « The expression of neurofilament protein and mRNA levels in the lateral geniculate nucleus and area V1 of the developing and adult vervet monkey (Ceorcopithicus aethiops) / ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0028/MQ50807.pdf.
Texte intégral
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Tanaka, Yusuke. « Visual responses to moving objects with invariant contours in the monkey superior temporal polysensory area(STP) ». 京都大学 (Kyoto University), 1999. http://hdl.handle.net/2433/182003.
Texte intégral
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Kidman, Gillian C. « Middle years school students' area judgement rules : A cross-sectional study ». Thesis, Queensland University of Technology, 2002. https://eprints.qut.edu.au/36667/1/36667_Digitised%20Thesis.pdf.
Texte intégralRésumé :
This study explored Years 4, 6 and 8 students' understanding of the area concept. In particular, it identified and explained students' intuitive judgement rules, that is, the method by which a person integrates information about perceived stimuli when comparing area of rectangular and near-rectangular regions when no length dimensions were given.
The study was based on the work of Anderson and Cuneo (1978) and the method of Information Integration Theory (IIT). IIT is a technique that classifies area judgement rules as additive, Area = Height + Width, where salient dimensions are added, or multiplicative, Area = Height x Width where salient dimensions are added.
Thirty-six students aged 9 to 13 years, twelve at the beginning, 12 at the middle, and twelve at the end of the area-formulae instructional sequence (Years 4, 6 and 8), were given three exercises. The first exercise involved the students estimating the sizes of rectangular regions on a graphic rating scale. The second and third exercises also involved estimation and the graphic rating scale, but used near-rectangular regions. An additional exercise containing area calculation tasks similar to those found in many text books and classrooms was also presented to the students.
The results of the study found that approximately one half of the students perceived area as being related to the sum of the rectangle's linear dimensions. Such students perceived that doubling the lengths of the sides of a rectangle doubles the area and were referred to as predominantly 'additive thinkers'. In estimating the size of rectangular regions, these students showed a preference for three strategies: vertical alignment of the test piece, use of a ruler (to measure the test piece), and use of the index finger (to measure the test piece informally). They also did not attempt many of the area calculation tasks, and for the ones they did attempt, they concentrated on boundary counting. Boundary counting included either grid line counting around the four sides of the figure or a count of the spaces around the four sides of the figure.
The proportion of additive students remained largely the same across the Years. That is, the students at the end of the area-formulae instructional sequence who had increased levels of instruction had not advanced beyond the students in the middle of the area-formulae instructional sequence. These students in turn did not appear to have advanced much beyond the capability exhibited by students at the start of the area-formulae instructional sequence. It was clear, particularly from the classroom tasks, that many of these students experienced confusion between area and perimeter irrespective of their level of area-formulae instruction. However, the proportion of students exhibiting additive thinking reduced for the near-rectangular regions. These regions appeared to divert some students' attention from the linear dimensions to the surface area of the regions.
Students who think multiplicatively in terms of their judgements of area were equally likely to use a form of perimeter to calculate area as were students who think additively in terms of area. Students who used a predominantly multiplicative integration of the stimulus cues should have been capable of correctly using multiplication to calculate the area of rectangles from the dimensions of the rectangles. This was found not to be the case in the area calculation tasks closely resembling classroom textbook area formula exercises. Over 65% of the multiplicative students were found to add the salient dimensions. They seemed to employ an additive integration of the dimensions indicating confusion with perimeter. Most students who employed multiplicative judgement rules were found to be more likely to draw a diagram and be able to calculate the area than students who employed additive judgement rules.
The majority of students experienced 'intra-individual' rule changes. In the case of the additive thinkers, for one of the three exercises they thought multiplicatively. Similarly for the multiplicative thinkers for one of the three exercises they thought additively. The area calculation task strategies for the additive thinkers and the multiplicative thinkers in this group were the same. They attempted all tasks and these attempts included calculations of perimeter, half perimeter as well as calculations of area through direct 1 to 1 counting of the congruent sub-regions. Computational errors also prevented these students from obtaining a correct area solution. For this group also, there was a lot of confusion between area and perimeter.
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Gilbert, Johann. « Étude et développement d'un réseau de capteurs synchronisés à l'aide d'un protocole de communication sans fil dédié à l'Internet des objets ». Thesis, Toulon, 2018. http://www.theses.fr/2018TOUL0012/document.
Texte intégralRésumé :
Depuis les 20 dernières années, l'essor de l'IoT et du "cloud computing" a conditionné le besoin dedéployer massivement, et globalement, des capteurs afin d'alimenter des bases de données et améliorerla précision des algorithmes d'analyse. Pour répondre à ces demandes, de nouveaux réseaux basés surles bandes de fréquences ISM ont été déployés. Nous avons donc appréhendé de façon complète cestechnologies afin de garantir une qualité maximale pour nos produits mais aussi proposer des conseilsjustes dans un secteur ou abus de langage et promesses de performances sont monnaie courante.Cependant, le nombre grandissant d'objets émettant sous la fréquence du gigahertz lève un doutequant à l'impact sur la santé des êtres vivants. Dès lors, coupler l'aspect non invasif des VLC avecl'Internet des Objets permettrait non seulement de réduire les risques pour les êtres humains maisaussi de limiter la saturation des bandes radio.Néanmoins, les techniques d'aujourd'hui consistent principalement en la réalisation de systèmesdiffusant l'information depuis une source unique vers plusieurs récepteurs, ce qui est l'inverse du paradigmede l'IoT. Dans cette étude, nous avons donc réalisé un nouveau design basé sur les VLC qui meten place une topologie de réseau en étoile 3. Ce système, basé sur un concentrateur disposant d'une ouplusieurs caméra en guise de photo-récepteurs, est optimisé pour plus d'autonomie. Ainsi, la vitessede transmission peut être gérée dynamiquement sans être connue par les autres éléments du systèmeIn the last 20 years, the coming up of Internet of Things and Cloud Computing has conditionedthe need to deploy sensors everywhere to feed databases and analytics. To meet this requirements,new kind of networks have been massively deployed based on the sub-gigahertz frequency which haveunknown effect on human health.Couple the non-invasive aspect of the Visible Light Communication (VLC) with IoT could notonly reduce potential risks for human health but also avoid radio band saturation. However, today'stechniques consist mainly in broadcast data from light sources to receivers which is the opposite of theIoT paradigm. In this study, we will present a new design where the gateway is not a classic photodiodebut a camera.With this camera based method, we are able to design a star network using VLC. Even if the datarate is not the same as standard method, we are now able to collect data emanating from many sensorsat once with only one photoreceptor. This system also includes the ability of discriminate LED matrix,which transfer the same data faster, and single LED. Finally, data rate can be handle autonomouslyby the system to provide an optimal data transfer
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Distefano, Alessandra. « The Effect of Emotions and Imagery Appeals on Visual Consumption Experiences ». Doctoral thesis, Università di Catania, 2014. http://hdl.handle.net/10761/1608.
Texte intégralRésumé :
There is currently a mismatch between our traditional models of consumer decision-making and the way consumers actually make decisions, at least for certain product categories. Multi-attribute models have been successful in modeling how consumers make decisions about frequently purchased products or services, where decision-making proceeds rationally. But these models cannot account for decisions in which less experience is available, where the problem is not well-structured, and where emotional reactions are important. Whereas traditional models assume verbal and semantic processes, the consumption vision perspective focuses on visual and imaginal processing. The consumption vision approach explicitly acknowledges creative sense-making processes consumers use to anticipate the future.
A consumption vision can be defined as a visual image of certain product-related behaviors and their consequences on decision-making processes. Consumption visions consist of concrete and vivid mental images that enable consumers to experience self-relevant consequences of product use. Based on the findings of several studies on consumption visions and on the role of anticipated emotions in consumption experiences, the goal of this study is to understand what triggers consumption visions, and consequently, in what direction consumption visions influence consumers decision making processes. I suggest that forming a consumption vision is one possible heuristic by which a consumer can decide among alternative courses of action. I discuss the possible effects of consumption visions on consumers cognitive and affective reactions to products, intentions, and behaviors. Three studies examine the mediating role of imagery accessibility during consumption experiences and demonstrate that the difficulty of imagery generation can reverse the generally observed positive effects on imagery appeals and consumption decisions. The same results indeed, can be achieved considering consumers predisposition to emotional experiences. When participants are low in imagery abilities (as well as when they show low need for emotion attitudes), whether there is or not an explicit invitation to imagine a consumption experience, or whether the product is present in a vivid manner or not, imagery appeals are not only ineffective, but even have a negative effect on product preferences. Moreover, this work aims to demonstrate that imagery fluency effect, given its subjective nature, is more likely for individuals with richer personal past experiences or with higher predisposition to use imagination (higher in need for emotions levels). Finally, I discuss how consumer researchers can integrate consumption visions into decision-making research.
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Murabito, Francesca. « Deeply Incorporating Human Capabilities into Machine Learning Models for Fine-Grained Visual Categorization ». Doctoral thesis, Università di Catania, 2019. http://hdl.handle.net/10761/4144.
Texte intégralRésumé :
Artificial intelligence and machine learning have long attempted to emulate human visual system.
With the recent advances in deep neural networks, which take inspiration from the architecture of the primate visual hierarchy, human-level visual abilities are now coming within reach of artificial systems. However, the existing computational models are designed with engineering goals, loosely emulating computations and connections of biological neurons, especially in terms of intermediate visual representations.
In this thesis we aim at investigating how human skills can be integrated into computational models in order to perform fine-grained image categorization, a task which requires the application of specific perceptive and cognitive abilities to be solved. In particular, our goal is to develop systems which, either implicitly or explicitly, combine human reasoning processes with deep classification models. Our claims is that by the emulation of the process carried out by humans while performing a recognition task it is possible to yield improved classification performance.
To this end, we first attempt to replicate human visual attention by modeling a saliency detection system able to emulate the integration of the top-down (task-controlled, classification-driven) and bottom-up (sensory information) processes; thus, the generated saliency maps are able to represent implicitly the way humans perceive and focus their attention while performing recognition, and, therefore, a useful supervision for the automatic classification system. We then investigate if and to what extent the learned saliency maps can support visual classification in nontrivial cases. To achieve this, we propose SalClassNet, a CNN framework consisting of two networks jointly trained: a) the first one computing top-down saliency maps from input images, and b) the second one exploiting the computed saliency maps for visual classification.
Gaze shifts change in relation to a task is not the only process when performing classification in specific domains, but humans also leverage a-priori specialized knowledge to perform recognition. For example, distinguishing between different dog breeds or fruit varieties requires skills that not all human possess but only domain experts. Of course, one may argue that the typical learning-by-example approach can be applied by asking domain experts to collect enough annotations from which machine learning methods can derive the features necessary for the classification. Nevertheless, this is a really costly process and often infeasible. Thus, the second part of this thesis aim at explicitly modeling and exploiting domain-specific knowledge to perform recognition.
To this end, we introduce and demonstrate that computational ontologies can explicitly encode human knowledge and that it can be used to support multiple tasks from data annotation to classification. In particular, we propose an ontology-based annotation tool, able to reduce significantly the efforts to collect highly-specialized labels and demonstrate its effectiveness building the VegImage dataset, a collection of about 4,000 images belonging to 24 fruit varieties, annotated with over 65,000 bounding boxes and enriched with a large knowledge base consisting of more than 1,000,000 OWL triples.
We then exploit this ontology-structured knowledge by combining a semantic-classifier, which performs inference based on the information encoded in the domain ontology, with a visual convolutional neural network, showing that the integration of semantics into automatic classification models can represents the key to solve a complex task such as the fine-grained recognition of fruit varieties, a task which requires the contribution of domain expert to be completely solved.
Performance evaluation of the proposed approaches provides a basis to assess the validity of our claim along with the scientific soundness of developed models.
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Hjärkéus, Erik, et Tim Larsson. « Riktade ljudeffekters påverkan på den visuella uppmärksamheten : En ögonrörelsestudie ». Thesis, Högskolan Dalarna, Bildproduktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-29347.
Texte intégralRésumé :
Eftersom att dagens biografer utvecklas med mer avancerad teknik för att rikta ljudeffekter på flera olika sätt är det viktigt att förstå vad den riktade ljudeffekten har för påverkan på betraktarna. Vi har undersökt hur den visuella uppmärksamheten skiljer sig vid uppspelning av riktade och ej riktade ljudeffekter. Detta har vi gjort med hjälp av en ögonrörelsestudie där deltagare har fått betrakta fyra anpassade filmsekvenser som vi har skapat själva. För att analysera vår data har vi använt oss av analysmetoden area of interest. Vårt resultat tyder på att det finns en skillnad i den visuella uppmärksamheten där vi till en viss grad kan styra tittarna med riktade ljudeffekter. Denna kunskap gör att filmskapare kan använda sig av riktade ljudeffekter som ett verktyg för att styra sin publik.
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Ortis, Alessandro. « Methods for Sentiment Analysis and Social Media Popularity of Crowdsourced Visual Contents ». Doctoral thesis, Università di Catania, 2019. http://hdl.handle.net/10761/4136.
Texte intégralRésumé :
This thesis collects all the research work done by the PhD candidate in the Joint Open Lab for Wireless Applications in multi-deVice Ecosystems (JOL WAVE Catania) of TIM Telecom Italia, which granted his doctoral fellowship.
The crowdsourcing paradigm opens new opportunities to understand various aspects of people's interactions, preferences and behaviors.
In this thesis we investigated methods aimed to infer people's reaction toward visual contents, under different headings.
We first focus on the task of understanding how people visit a place (e.g., a cultural heritage site) and infer what catch most their attention and interest, by means of the analysis of the shared photos taken by the users themselves.
Then, addressing the issues related to the noisy text associated to images, we defined a method for Image Popularity Prediction, considering an alternative source of text automatically extracted from the visual content. We first highlight the drawbacks of the text used in most of the state of the art methods, and then experimentally compared the two sources of text.
Starting from the analysis of the state of the art in image popularity prediction, we observed that a time-aware approach is needed, as the temporal normalization commonly employed in literature makes two contents published at different times incomparable. For this reason we introduced a new task, named Image Popularity Dynamics Prediction, which aims to predict the evolution of the engagement scores of a photo over a period of 30 days from its upload. To challenge the problem, we introduce a large scale dataset of 20K photos whose engagement scores have been tracked for 30 days. Moreover, we presented an approach that is able to perform the prediction at time zero.
Furthermore, we investigated methods for scene popularity estimation, from a set of videos taken by people attending a public event.
This involved the definition of methods for unsupervised video segmentation and scene clustering, able to work in both mobile and wearable domains.
The methods have been developed considering unconstrained scenarios without any prior on the input videos. In appendix, we also report some additional results and the pseudocode of the developed algorithms.
35
Ziesche, Arnold, et Fred H. Hamker. « Brain circuits underlying visual stability across eye movements—converging evidence for a neuro-computational model of area LIP ». Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-147862.
Texte intégralRésumé :
The understanding of the subjective experience of a visually stable world despite the occurrence of an observer's eye movements has been the focus of extensive research for over 20 years. These studies have revealed fundamental mechanisms such as anticipatory receptive field (RF) shifts and the saccadic suppression of stimulus displacements, yet there currently exists no single explanatory framework for these observations. We show that a previously presented neuro-computational model of peri-saccadic mislocalization accounts for the phenomenon of predictive remapping and for the observation of saccadic suppression of displacement (SSD). This converging evidence allows us to identify the potential ingredients of perceptual stability that generalize beyond different data sets in a formal physiology-based model. In particular we propose that predictive remapping stabilizes the visual world across saccades by introducing a feedback loop and, as an emergent result, small displacements of stimuli are not noticed by the visual system. The model provides a link from neural dynamics, to neural mechanism and finally to behavior, and thus offers a testable comprehensive framework of visual stability.
36
Li, Jin. « The typical and atypical development of the visual word form area : the role of innate connectivity and experience ». The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1593448336086218.
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Wheat, Katherine L. « The role of Broca's area for phonology during visual word recognition : investigations using magnetoencephalography and transcranial magnetic stimulation ». Thesis, University of York, 2012. http://etheses.whiterose.ac.uk/2082/.
Texte intégralRésumé :
This thesis explored a possible role of Broca's area (specifically the pars opercularis of left inferior frontal gyrus and neighbouring precentral gyrus; LIFGpo/PCG) in accessing sublexical phonology during visual word recognition. In Experiments 1 to 4, behavioural masked sublexical phonological priming effects were tested during lexical decision and reading aloud in English. No sublexical phonological effects were found during the lexical decision tasks, but significant sublexical phonological priming effects were found during reading aloud. In Experiment 5, masked sublexical phonological priming effects were then tested during a silent reading task using magnetoencephalography. Sublexical phonological priming effects were localised to LIFGpo/PCG within ~200 ms for real word targets and within ~75 ms for nonword targets. This indicates an early sensitivity to sublexical phonological information at LIFGpo/PCG during silent reading of English. In Experiment 6 chronometric functional magnetic resonance imaging guided transcranial magnetic stimulation was used to create focal and transient virtual lesions to LIFGpo/PCG in order to test the hypothesis that the putative early sublexical phonological representations seen at LIFGpo/PCG are functionally necessary for visual word recognition. Dutch participants underwent transcranial magnetic stimulation during reading aloud as compared to picture naming. An early disruption to word reading that was not present for picture naming would be evidence in favour of a necessary role of LIFGpo/PCG during early visual word recognition processes, as opposed to disruption of later speech production processes that are common to reading and naming. Experiment 6 failed to demonstrate that this region is functionally necessary for reading aloud prior to 200 ms in Dutch. The combination of findings in this thesis lead to many possible interpretations, which cannot be ruled in or out without further investigation. As yet, the functional significance of this early LIFGpo/PCG activation, therefore, remains unclear.
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Berman, Daniel. « From Photons to Photos : Mapping Functional and Organizational Properties of Human Visual Cortex with fMRI ». The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1422972281.
Texte intégral
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Giovannardi, Gianmarco. « Geometric properties of 2-dimensional minimal surfaces in a sub-Riemannian manifold which models the Visual Cortex ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11473/.
Texte intégralRésumé :
In this paper we study the notion of degree forsubmanifolds embedded in an equiregular sub-Riemannian manifold and we provide the definition of their associated area functional. In this setting we prove that the Hausdorff dimension of a submanifold coincides with its degree, as stated by Gromov. Using these general definitions we compute the first variation for surfaces embedded in low dimensional manifolds and we obtain the partial differential equation associated to minimal surfaces. These minimal surfaces have several applications in the neurogeometry of the visual cortex.
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Westraadt, Georina. « The potential for facilitating a rich variety of learning opportunities through the learning area arts and culture (visual arts) ». Thesis, [S.l. : s.n.], 2007. http://dk.cput.ac.za/cgi/viewcontent.cgi?article=1032&context=td_cput&preview_mode=1&z=1243931944.
Texte intégral
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Stevens, James Barrie. « Preferences for visual attributes in the process of selection and location of street trees in the Brisbane metropolitan area ». Thesis, Queensland University of Technology, 1995. https://eprints.qut.edu.au/36248/1/36248_Stevens_1995.pdf.
Texte intégralRésumé :
Preference for visual attributes in the process of selection and location
of street trees in Brisbane
This thesis seeks to establish the attributes of streetscapes that are important to
people who live in the city of Brisbane. It develops and tests a methodology for
determining streetscape preference. The research methodology is based on an
adaptation of the 'psychophysical' paradigm for landscape assessment using
analysis of primary data collected in the study area (Brisbane metropolitan area).
The analysis has yielded original findings relating street scale with public
preference.
The preference for 30 suburban streetscapes depicting a typical range of street
trees of many sizes, species, locations and densities was assessed by 28 people of
varying age, vocation and interests. The assessment records of those selected
were compared with objective measurements of the tree/street scale. A second
expert assessment of 'scale' and 'contrast' was made and also compared with the
objective scale measurements and public preference assessments, to identify any
relationship between expert 'scale' and 'contrast' and public preference.
Judgements of preference were found to have a relationship with objective scale
ratios expressed as decimals, having an optimum value in the region of 0.618.
Analysis of the contribution of attributes to preference suggested that the
following attributes were significant, ranked in priority:
1. a high degree of axial symmetry, with trees of similar foliage density
2. well formed mature tree specimens, with prominent foliage
3. trees spaced to permit continuous canopies as a corridor or enclosure
4. a clear minimum height of approximately two metres to the underside of
foliage
5. evidence of human intervention was at a minimum
6. there was an optimum visible length of street preferred.
Analysis of expert 'scale' assessments indicated a relationship which, when
graphed, changed character approximately coinciding with peak preference. This
indicated strong sensitivity to 'scale' up to the public's peak preference, thereafter
being less so. Analysis of means of expert 'contrast' assessments was
inconclusive, in that only the most generalised trend could be identified within the
data. This indicates that more specific aspects of contrast might be studied for
potential correlation.
Integration with related areas of research is discussed and recommendations for
further research are given. Applications of the research to landscape design are
__ outlined in the concluding chapter of the thesis.
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Mi, Liang. « A Testbed for Design and Performance Evaluation of Visual Localization Technique inside the Small Intestine ». Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/620.
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Wireless video capsule endoscopy (VCE) plays an increasingly important role in assisting clinical diagnoses of gastrointestinal (GI) diseases. It provides a non-invasive way to examine the entire small intestine, where other conventional endoscopic instruments can barely reach. Existing examination systems for the VCE cannot track the location of a endoscopic capsule, which prevents the physician from identifying the exact location of the diseases. During the eight hour examination time, the video capsule continuously keeps taking images at a frame rate up to six frame per sec, so it is possible to extract the motion information from the content of the image sequence. Many attempts have been made to develop computer vision algorithms to detect the motion of the capsule based on the small changes in the consecutive video frames and then trace the location of the capsule. However, validation of those algorithms has become a challenging topic because conducting experiments on the human body is extremely difficult due to individual differences and legal issues. In this thesis, two validation approaches for motion tracking of the VCE are presented in detail respectively. One approach is to build a physical testbed with a plastic pipe and an endoscopy camera; the other is to build a virtual testbed by creating a three-dimensional virtual small intestine model and simulating the motion of the capsule. Based on the virtual testbed, a physiological factor, intestinal contraction, has been studied in terms of its influence on visual based localization algorithm and a geometric model for measuring the amount of contraction is proposed and validated via the virtual testbed. Empirical results have made contributions in support of the performance evaluation of other research on the visual based localization algorithm of VCE.
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Seeloff, Desiree Machelle. « But is it local ? A Content Analysis of Farm-to-Table Restaurants within the Columbus Metropolitan Area ». The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494289333534779.
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Johnson, Bryan Fisher. « Influence of Several Herbicides on Visual Injury, Leaf Area Index, and Yield of Glyphosate-Tolerant Soybean (Glycine max) ». Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/32295.
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The occasional failure of glyphosate to control all weeds throughout the entire growing season has prompted growers to sometimes use herbicides other than glyphosate on glyphosate-tolerant soybean. Field studies were conducted in 1999 and 2000 to investigate potential crop injury from several herbicides on glyphosate-tolerant soybean, and to determine the relationship between soybean maturity, planting date, and herbicide treatment on soybean injury, leaf area index (LAI), and yield. Three glyphosate-tolerant soybean cultivars representing maturity groups III, IV and V were planted at dates representing the full-season and double-crop soybean production systems used in Virginia. Within each cultivar and planting date, 15 herbicide treatments, in addition to a control receiving only metolachlor preemergence, were applied to cause multiple levels of crop injury. Results of this study indicate that glyphosate-tolerant soybean generally recovered from early-season herbicide injury and LAI reductions; however, reduced yield occurred with some treatments. Yield reductions were more common in double-crop soybean than in full-season soybean. In full-season soybean, most yield reductions occurred only in the early maturing RT-386 cultivar. These yield reductions may be attributed to the reduced developmental periods associated with early maturing cultivars and double-crop soybean that often lead to reduced vegetative growth and limited LAI. Additional reductions of LAI by some herbicide treatments on these soybean may have coincided with yield reductions; however, reduced LAI did not occur with all yield reducing treatments. Therefore, soybean LAI response to herbicide treatments does not always accurately indicate the potential detrimental effects of herbicides on soybean yield. Further, yield reductions associated with herbicide applications occurred, although soybean sometimes produced leaf area exceeding the critical LAI level of 3.5 to 4.0 which is the minimum LAI needed for soybean to achieve maximum yield.Master of Science
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Buffalo, Elizabeth Ann. « Memory, visual perception, the perirhinal cortex, and area TE : findings from behavioral studies in monkeys and in human amnesic patients / ». Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9911843.
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La, Delfa Gaetano Carmelo. « Methodologies and Technologies for Indoor Localization : a Computer Vision Based Approach ». Doctoral thesis, Università di Catania, 2016. http://hdl.handle.net/10761/3928.
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The massive diffusion of smartphones we are seeing in the last years, the growing interest for everything related to wearable devices and Internet of Things (IoT), the exponential rise of Location Based Services (LBS: services based on the position of the users and accessible through the device) has meant that technologies capable of determining the position of the user inside a specific context have taken a crucial role in the consumer sector. In outdoor environments, GPS (Global Positioning System) can be considered today as a standard de facto , while the localization and navigation in indoor environments still remains one of the technological challenges of the next years.
Indoor Positioning Systems (IPS) have a remarkable importance in a lot of important market segments such as the retail sectors for con- textual advertising (commercial centers, supermarkets), touristic and transportation sectors (airports, museums), healthcare sectors (hospitals). Sometimes, in emergency situations they can make the difference between life and death. Even if actually doesn t exist a definitive solution as efficient and precise as GPS and with all its advantages, various approaches and methodologies has been proposed in the last years in scientific literature, and several technologies are appearing into the market. The researches have focused, rather than on realizing a general purpose IPS with high performances everywhere, on the development of a variety of solutions suitable for the specific place of deployment and which meet the specifics precision, security, invasiveness and cost requirements.
In the first part of this doctoral dissertation, after an overview on the main methodologies used for locating a user in an indoor environment, we will analyze the state of the art and present some of the most interesting cases. We will focus particularly on approaches which utilize the smartphone s inertial sensors and 2D visual markers based computer vision techniques. In the second part of the dissertation we will propose our own solution to the indoor localization problem. Such solution consists in a visual markers system deployed onto the area of interest s floor and a step detection algorithm. We will compare the performances of three types of markers, taken from the scientific literature, from the point of view of the specifications required by the suggested solution, and choose the most better performing one. We will then propose a client - server architecture for managing the whole process of tracking the user inside a building, and present an implementation of the client, on the iOS platform. Finally in the last part of the dissertation, we will show the obtained results, and talk about the possible future works.
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PAPA, Dorina. « Visual perception of the historic city image. An urban landscape approach to integrate the residual margins of the historical area. Gjirokastra case study ». Doctoral thesis, Università degli studi di Ferrara, 2018. http://hdl.handle.net/11392/2478771.
Texte intégralRésumé :
This thesis investigates the integrity of the historic city image in relation to human’s visual perception and the possibility to extend this quality to the fragile margins of the historical area in order to achieve a historical urban landscape as a whole and to guarantee visual sustainability as an important component of historical urban development.
In Albanian context, numerous historic cities or traditional settlements following the recent rapid urban growth and upgrade interventions have caused a degradation of the historical urban landscape reflecting a chaotic image made up of separate fragments which do not fit with each other visually and are not posed in harmony with the historical center. Thus, these inconsistent transformations not only harm the quality of the historical landscape as a whole, but they further disturb the visualizing of the historical center, putting at risk the preservation of the historic urban landscape as a whole. Hence, these new inconsistent transformations which provoke disorientation and distress at a psychological level, can cause a lack of interest for the visual frame of the traditional area and provoke a cognitive dissonance or rejection towards it, being foreign to the collective consciousness used to the idea of visual coherence and harmony of the historical center, which has the capacity to activate visual comprehension, and the desire to experience it.
While on one hand, the current interventions seem to fulfill almost the best functional requirements which are numerically quantified and objectively discussed, on the other hand, the principle of visual integrity started gradually lacking as they still seem to be vague and subjective.
Even the legal framework, when considering new interventions in the protected residual areas around the historical centers, although aims to conserve the historical city image by emphasizing the importance of interventions “in harmony” with the visual and morphological character of the historical center, do not provide objective parameters to assess this harmony.
Accordingly, the aim of this research is to determine a series of constants that characterize the historical city image which will constitute the parameters of evaluation of its visual sustainability and will be used as tools for new interventions in the residual margins. Taking as a case study the historic center of Gjirokastra, in Albania, the research will focus on understanding and represent at an urban scale the visual perceptual characteristics of the historical landscape.
The final outcome of the thesis is the representation of the synthesis of Gjirokastra image. These synthetic representations constitute the basis for the guidelines and recommendations for adjusting interventions in the residual area around the historical center. They can be further used as a design tool to transmit the visual quality in new design projects.
Moreover, the research intends to be relevant and original, as it presents a methodology to analyze and define the quality of the historical city image, which has not been an object of previous studies in Albania, and which can be used in other historical cities or settlements in Albania and in a wider context.
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Vilela, Estrada Martín A., Chumacero Mary M. Araujo, Zapata Fiorela E. Solano, Adrianzén Aarón Dávila et Christian R. Mejia. « Agudeza visual baja según residir en una ciudad rural del norte del Perú : estudio de casos y controles ». Elsevier B.V, 2016. http://hdl.handle.net/10757/614919.
Texte intégralRésumé :
Introduction In Peru, there are few studies which show that they might be a difference between school children in rural areas and the ones from non-rural areas, this is necessary because it has been shown that the place of residence is an influential exogenous factor in the development of low visual acuity. Likewise, the influence of environment on the development of visual errors and low visual acuity has been demonstrated. Methodology Case-control study between child population of an urban and a rural area (Piura and Joras); prior informed consent of their parents. The primary variable was the visual acuity, qualified with the principles of Snellen (sensitivity 85%, specificity 96%) 20/0 was considered as optimal and normal visual acuity was considered to 20/25. Values below were low visual acuity. Results 1,094 were surveyed. 50.0% (488) were female, and the median age was 9 years (interquartile range: 7-10 years). 22.6% (221) of the children had low visual acuity. In bivariate analysis, the age of children (p = .001), the degree coursing (p <.001) and city of residence (p = .005) were associated with low visual acuity of children. The multivariate analysis found that non-rural children had 1.55 (95% CI: 1.14 to 2.11, p-value = .005) more chances of having low visual acuity, adjusted for sex, age and degree academic growth of children. Conclusions It is concluded that children living non-rural residences have more low visual acuity in the northern Peru.Revisión por pares
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Averna, Guido. « SIRENE un linguaggio di programmazione visuale per la didattica della programmazione ». Doctoral thesis, Università di Catania, 2018. http://hdl.handle.net/10761/4180.
Texte intégralRésumé :
Dalla metà del ventesimo secolo vi è stato un aumento della diffusione dei personal computer dovuto ad una crescente domanda nel mercato di questo elaboratore grazie alla sua riduzione sia di prezzo e sia di dimensioni. Questo ha permesso, a molte persone, di poter utilizzare i computer per le più svariate finalità e non soltanto per attività di tipo strettamente scientifico o accademico. La facilità di utilizzo, dovuta alle interfacce Uomo-Macchina, e le potenzialità di utilizzo dei personal computer hanno portato le comunità scolastiche ed accademiche, nazionali ed internazionali, a sviluppare corsi di programmazione a ogni livello. In questi anni, dunque, sono stati sviluppati molti strumenti utili all implementazione di programmi: molti di questi usano un paradigma text-based mentre solo pochi strumenti usano un paradigma visuale, o iconico. Questo lavoro propone un framework iconico di programmazione utile all insegnamento ed all apprendimento dell arte della programmazione, a livello sia concettuale e sia implementativo, in un contesto collaborativo e distribuito in rete sfruttando le più recenti tecnologie per una condivisione, in tempo reale, dell ambiente di lavoro e degli algoritmi e programmi sviluppati tra il docente, o l esperto , e gli studenti, o i principianti . Si discuterà delle difficoltà comuni che hanno gli studenti dei corsi di programmazione e lo stato dell arte attuale degli strumenti iconici di sviluppo utili all insegnamento e all apprendimento della programmazione. Dunque, si presenterà un framework iconico, SIRENE, che possiede caratteristiche real-time, è cooperativo, usabile in ogni dispositivo ed in internet ed è progettato per l insegnamento e l apprendimento della programmazione. Si discuterà della sua implementazione, argomentando anche delle varie difficoltà implementative riscontrate e le loro soluzioni. Si perverrà, infine, alla conclusione analizzando una sperimentazione ed i suoi risultati e la realizzazione del framework visuale, dei suoi possibili usi pratici, delle sue potenzialità e delle sue possibili estensioni.
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McGraw, Cathy. « Montreal Association for the Blind user satisfaction survey ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ37290.pdf.
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