Dissertations / Theses on the topic 'Color categorization'

L’objectif central de cette thèse consiste à étudier les effets des couleurs associées au genre, particulièrement bleu et rose, sur la perception du sexe des visages. Les enregistrements électrophysiologiques de surface (potentiels évoqués cérébraux) et les données comportementales issus de mon travail indiquent que la perception du visage, au-delà de sa dimension physiologique, est soumise à l’influence de processus top-down induits par le stéréotype de la couleur bleue pour le genre masculin et de la couleur rose pour le genre féminin. Ces influences s’observent précocement au cours de l'étape d'encodage perceptif des visages
The present thesis aims at studying the impact of the colors associated to gender, particularly blue and pink, on the perception of face gender. Our electrophysiological and behavioral data indicate that the perception of the face, beyond its physiological dimension, is subject to the influence of top-down processes induced by pink for female and blue for male stereotype. These influences are evident at early perceptual stage of face processing

Le concept de fraîcheur a été récemment étudié en sciences du consommateur en raison de sa dimension hédonique influençant les préférences des consommateurs. Les études antérieures ont conclu que la fraîcheur pouvait résulter d’une intégration multisensorielle des signaux olfactifs, gustatifs, trigéminaux, visuels et auditifs. Dans les boissons, la fraîcheur est également complexe au niveau sémantique puisqu'elle peut avoir des significations différentes. La plupart des études se sont concentrées sur les attentes des consommateurs à partir de données déclaratives. Compte tenu de la complexité des mécanismes cognitifs impliqués, des mesures plus objectives du comportement sont apparues nécessaires. Dans cette thèse, nous avons ciblé l’influence des interactions audiovisuelles à partir desquelles les consommateurs perçoivent une boisson comme fraîche, avant la dégustation. Nos résultats révèlent que des stimuli audiovisuels liés à la température et la carbonatation influencent positivement la fraîcheur perçue. L'existence d’effets de correspondance audiovisuelle entre la taille des bulles et la hauteur des sons dans les boissons pétillantes ont également été montrés et se sont avérés être robustes à des variations du stimulus ainsi qu’au paradigme expérimental utilisé. Enfin, les effets de correspondance observés entre taille des bulles et hauteur du son seraient plus susceptibles de se produire lorsque l’attention des participants est dirigée sur les caractéristiques pour lesquelles la correspondance est testée. Certains mécanismes cognitifs sous-tendant la perception multisensorielle de fraîcheur pourraient aider à augmenter l'attractivité et l'appréciation des boissons
The concept of freshness has received recent consideration in the field of consumer science, mainly due to its hedonic dimension, assumed to influence consumers’ preference and behavior. Previous studies concluded that freshness could be defined as the result of the multisensory integration of olfactory, gustatory, trigeminal, visual, and auditory cues. In the case of beverages, freshness is also complex at a semantic level since it conveys different meanings. Up to now, most studies focused on consumers’ expectations by a collection of declarative data. Given the complexity of the perceptual and cognitive mechanisms involved, this approach needed to be completed by more objective measures of behavior. In this thesis, we focus on the influence of audiovisual interactions from which consumers can perceive a beverage as fresh, before tasting. The first experiments revealed that audiovisual stimuli cuing temperature and carbonation positively influence the perception and categorization of freshness in beverages. The second experiments revealed the existence of audiovisual crossmodal correspondence effects between bubbles size and pouring sounds pitch in carbonated beverages that were robust to variations of the stimulus context as well as the experimental design used. A final experiment revealed that the Pitch-Size correspondence effects in beverages are more likely to occur when the participants’ attention is directed toward the same features on which the correspondence is tested. Applications such as the triggering of perceptual and cognitive mechanisms underpinning the multisensory perception of freshness could help to increase beverages’ attractiveness and appreciation

Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-10-04T13:38:28Z No. of bitstreams: 1 GEISA PERAL GIMENES MARTINS.pdf: 1580175 bytes, checksum: 8f822a47410e0626bff8ea2311ea33fc (MD5)
Made available in DSpace on 2017-10-04T13:38:28Z (GMT). No. of bitstreams: 1 GEISA PERAL GIMENES MARTINS.pdf: 1580175 bytes, checksum: 8f822a47410e0626bff8ea2311ea33fc (MD5) Previous issue date: 2017-02-17
In this dissertation we present the results of the research on the initiative of the State Department of Education of S?o Paulo that, using the results of school performance in SARESP and data of school dropout, categorized or ranked schools in the colors blue, green, yellow, orange or red, in order to understand the trajectory, the operation and the reactions triggered by this governmental initiative in the educational scenario. In order to achieve the proposed objectives, we carried out a bibliographic research and established the state of the art in the academic-scientific literature regarding the categorization or ranking of schools by color, empirical research in order to understand the operation, implementation and extinction of this initiative in the light of perceptions of the school directors and regional directorates of education managers and, finally, documentary research, to study the repercussion of the implementation from the news reports published in the mainstream press, in the trade union press and in data on legal proceedings instituted against the Education of the State of S?o Paulo. The research pointed out that in the academic-scientific literature, in the mainstream press and in the legal media, there is a tendency to value the awards received by schools that obtained high performance in SARESP, with predominantly negative-biased speeches on schools ranking by color, focusing on the resistance of the teachers' union and teachers' dissatisfaction with the neoliberal logic that would be present in the government policies of the PSDB, with a reduced emphasis on positive aspects related to the actions of the State Department of Education. School principals and regional directories of education managers pointed out several positive points related to the categorization or ranking of schools by color, such as the motivation of the school teams that wanted to improve their results, the reflection of the pedagogical practice regarding the results obtained, the secretariat's investments in training courses, funds for underperforming schools, the simplicity of the quality indicator, and the fact that the results of ranking schools took teachers out of a comfort zone. However, the negative points, such as the stigmatization of poor-performing school-based school teams, motivated parents to transfer their children to better-performing schools, as well as the lack of clarity regarding the criteria used in schools ranking, accentuated the dissatisfaction and discomfort of many teachers with the actions that subsidized the categorization or ranking of color schools and raised the level of tension between teachers and the state secretariat of education, pressing the state government to extinguish the initiative in 2002, soon after its implementation.
Por meio da presente disserta??o apresentamos os resultados da pesquisa sobre a iniciativa da Secretaria de Educa??o do Estado de S?o Paulo que, utilizando-se dos resultados do desempenho escolar no SARESP e dados da evas?o escolar, categorizava ou classificava as escolas nas cores azul, verde, amarelo, laranja ou vermelho, com vistas a compreender a trajet?ria, o funcionamento e as rea??es desencadeadas por essa iniciativa governamental no cen?rio educacional. Para atingir os objetivos propostos, realizamos pesquisa bibliogr?fica e estabelecemos o estado da quest?o na literatura acad?mico-cient?fica referente a categoriza??o ou classifica??o das escolas por cores, pesquisa emp?rica com vistas a compreender o funcionamento, a implementa??o e a extin??o dessa iniciativa ? luz das percep??es dos diretores de escola e de gestores das diretorias regionais de ensino e, por fim, pesquisa documental, para estudar a repercuss?o da implementa??o a partir das not?cias veiculadas na grande imprensa, na imprensa sindical e em informa??es constantes de processos judiciais instaurados contra a Secretaria de Educa??o do Estado de S?o Paulo. A pesquisa apontou que na literatura acad?mico-cient?fica, na grande imprensa e nos meios legais h? uma tend?ncia de se valorizar as premia??es recebidas pelas escolas que obtiveram alto desempenho no SARESP, com predomin?ncia de discursos com vi?s negativo sobre a classifica??o das escolas por cores, focados na resist?ncia do sindicato dos professores e na insatisfa??o de professores com a l?gica neoliberal que estaria presente nas pol?ticas governamentais do PSDB, havendo reduzida ?nfase em aspectos positivos relacionados ?s a??es da secretaria estadual de educa??o. Os diretores de escola e gestores das diretorias regionais de ensino apontaram diversos pontos positivos relacionados ? categoriza??o ou classifica??o das escolas por cores, como por exemplo, a motiva??o das equipes escolares que desejavam melhorar seus resultados, a reflex?o da pr?tica pedag?gica diante dos resultados obtidos, os investimentos da secretaria em cursos de capacita??o, as verbas para as escolas com baixo desempenho, a simplicidade do indicador de qualidade e o fato de que os resultados da classifica??o das escolas tiraram os professores de uma zona de conforto. Entretanto, os pontos negativos, como por exemplo a estigmatiza??o das equipes escolares com o r?tulo de ruins que as escolas de baixo desempenho ficaram motivavam pais a transferir seus filhos para escolas com melhor desempenho, e, ainda, a falta de clareza quanto aos crit?rios utilizados na classifica??o das escolas, acentuaram a insatisfa??o e o desconforto de muitos professores com as a??es que subsidiavam a categoriza??o ou classifica??o das escolas por cores e elevaram o n?vel de tens?o entre os professores e a secretaria estadual de educa??o, pressionando o governo estadual a extinguir a iniciativa no ano de 2002, logo ap?s a sua implementa??o.

This thesis deals with content based automatic photo categorization. The aim of the work is to experiment with advanced techniques of image represenatation and to create a classifier which is able to process large image dataset with sufficient accuracy and computation speed. A traditional solution based on using visual codebooks is enhanced by computing color features, soft assignment of visual words to extracted feature vectors, usage of image segmentation in process of visual codebook creation and dividing picture into cells. These cells are processed separately. Linear SVM classifier with explicit data embeding is used for its efficiency. Finally, results of experiments with above mentioned techniques of the image categorization are discussed.

Visose pasaulio kalbose yra terminai spalvoms reikšti, tačiau priklausomai nuo ekstralingvistinių veiksnių, skirtingos tautos turi nevienodą jų skaičių. Išanalizavę dešimtis kalbų lingvistai B. Berlinas ir P. Kėjus nustatė, jog ankstyvame kalbų raidos etape tebuvo du žodžiai spalvoms apibrėžti: vienas - tamsioms, kitas – šviesioms. Šviesai atstovauja balta spalva, tamsai – juoda. Į prototipines baltumo ir juodumo konceptų reikšmes (baltas, -a – sniego spalvos, visai šviesus, juodas, -a – visiškai tamsus, kaip anglis) remiasi nemažai metaforinių reikšmių. Šio magistro darbo tikslas – išskirti skirtingas ir bendras baltumo ir juodumo metaforines reikšmes, būdingas lietuvių ir anglų kalboms. Tyrimo medžiagą sudaro lietuvių kalbos tekstyno grožinės literatūros blokas ir anglų kalbos tekstyno medžiaga. Išanalizavus tekstyno medžiagą nustatyta, jog prototipinės juodo reikšmės: tamsus, neperregimas, tankus, gilus; nešvarus, suteptas; rasė, gymis; rūšies pavadinimas; kava, arbata; metaforinės reikšmės: nešvarus, nedoras; prastas apie maistą (tik lietuvių kalboje); blogis: a) viduje išgyvenamas (emocijos); b) bauginantys, tragiški, nelaimingi įvykiai, su jais sietinos vietos; sunkus, kasdienis; neteisėta veikla, tokios veiklos rezultatai; simbolinės reikšmės: artėjančios nelaimės simbolis; nelaimės pranašai (blogio simboliai); gedulo simbolis. Tekstyno medžiagos analizė parodė, jog prototipinės balto reikšmės: šviesa; perregimas, bespalvis; švara; tuštuma; rasė, gymis; rūšies... [toliau žr. visą tekstą]
Every language has colour terms, but different amount of them depending on extra linguistic features. Linguist B. Berlin and P. Kay analysed dozens of languages and determined that there were only two colour terms (dark and bright) in the first stage of language evolution. Bright is represented by white and dark is represented by black. Many metaphoric meanings are based on prototypical meanings of concepts of whiteness (white – of colour of snow, very bright) and blackness (black – very dark, like coal). The goal of this master thesis is to determine common and different metaphorical meanings of whiteness and blackness characteristic for Lithuanian and English languages. The research material is collected from corpuses of Lithuanian and English languages. The data of the analysis of both concepts showed, blackness and whiteness in most cases are used to identify a feature of colour, i.e. prototypical colour meaning. But it also revealed a number of cases when the colour term does not denote a colour feature, but it is used metaphorically, with objects lacking the colour feature. The analysis has also revealed the importance of the symbolic meaning in the research of the colour concepts. The concept of Blackness in both languages is perceived similarly. Prototypical meanings are the following: dark, lacking light, impenetrable, soiled; used to characterize dark skin pigmentation; certain object in black colour (blackcurrant, black bread and etc.); (coffee or tea) without... [to full text]

Nous avons examiné comment des lésions cérébrales chez l'homme affectent les interdépendances entre trois modules de traitement cortical de la couleur, notamment : la perception, la dénomination et la connaissance de la couleur de l'objet. Nous avons étudié la catégorisation des couleurs - un exemple de l'interaction entre la perception et le langage. Les preuves provenant du développement cognitif, de la psychologie comparée et des neurosciences cognitives suggèrent que la catégorisation des couleurs ne provient ni de la perception ni du langage, comme le présume le débat Nature-Nurture. Les catégories de couleurs peuvent plutôt refléter des objets pertinents dans l'environnement. Pour évaluer la causalité entre la catégorisation et la dénomination, nous avons étudié un patient victime d'un AVC, le RDS. Malgré de difficultés pour nommer les couleurs chromatiques, résultant d’une lésion occipito-temporale gauche, la catégorisation des couleurs était relativement épargnée chez RDS. Des expériences d'IRM multimodale ont révélé que la connectivité perception-langage est essentielle pour un nommage efficace des couleurs, mais pas pour une catégorisation. L’étude de la connaissance de la couleur des objets dans le contexte de la dégradation des noms de couleurs de RDS a montré que celui-ci ne pouvait pas lier la perception des couleurs au langage ni à la connaissance sémantique. Il ne pouvait pas associer une couleur visuelle à un nom de couleur ou à la forme de son objet typique. Globalement, nous avons démontré trois ségrégations fonctionnelles dans le traitement cortical des couleurs, entre : (1) la catégorisation et la dénomination des couleurs, (2) la dénomination des couleurs chromatiques et achromatiques et (3) la connaissance des objets colorés et celle des couleurs abstraites. Les mécanismes corticaux du traitement des couleurs pourraient avoir pour objectif de lier des informations sensorielles et sémantiques afin de guider le comportement lié aux objets, en réalisant (1) une perception des couleurs stable, (2) des catégories de couleurs pertinentes et (3) des représentations mentales communes des formes et des couleurs. L'évolution culturelle peut avoir recyclé les circuits neuronaux nécessaires à ces processus pour isoler la couleur de l'objet et l'étiqueter avec des noms de couleur
We examined the effects of brain lesions in humans on the interdependences between three modules of cortical colour processing, namely colour perception, naming and object-colour knowledge. We first focused on colour categorisation - a case-in-point of the interplay between perception and language. Reviewed evidence from cognitive development, comparative psychology and cognitive neuroscience hints that colour categorisation originates from neither perception nor language, as assumed by the Nature-Nurture debate. Instead, colour categories may reflect relevant objects in the environment. To assess the causal link between categorization and naming, we investigated a stroke patient, RDS. Despite severe difficulties in naming chromatic colours, due to a left occipito-temporal lesion, RDS’s colour categorisation was relatively spared. Multimodal MRI experiments revealed that the language-perception connectivity is essential for efficient colour naming but not for categorisation. Investigation of object-colour knowledge in the context of RDS’s colour-naming impairment showed that RDS could not link colour perception to neither language nor semantic knowledge. He could not associate a visual colour to a colour name or to the shape of its typical object. Overall, we demonstrated three functional segregations in colour processing: between (1) colour categorisation and colour naming, (2) naming of chromatic and achromatic colours and (3) knowing about coloured objects and knowing about abstract colours. The main purpose of high-level cortical colour mechanisms could be providing sensory and semantic information to guide object-related behaviour, by achieving (1) stable colour perception, (2) relevant colour categories, and (3) joint mental representations of shapes and colours. These neural computations may have been recycled in cultural evolution to isolate colours from objects and label them with names

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro
Lançando um olhar sociocognitivista sobre um fenômeno geralmente estudado sob outros pontos de vista (textual e interacional), este estudo descreve as funções sociocognitivas das repetições lexicais e sintáticas em um contexto socialmente situado: o discurso político de Fernando Collor datado das eleições de 1989. Tendo em vista os fatores de ordem pragmática que emergem desse contexto, principalmente o propósito comunicativo, combinamos bases teóricas em Processamento do Discurso e Semântica Cognitiva para construir hipóteses que explicassem a saliência das repetições no discurso político de Collor. A análise qualitativa dos dados aponta para o uso da repetição enquanto estratégia lingüístico-discursiva útil na construção argumentativa e na diminuição do custo de processamento do discurso, alinhando-se, portanto, aos propósitos de convencimento e alcance das massas.
Departing from traditional analyses of repetition (textual and interactional), this study analyzes it within the light of Cognitive Linguistics. Its objective is to describe the sociocognitive functions of lexical and syntactic repetitions in a situated context: The political discourse of Fernando Collor de Melo, during the 1989 election campaign in Brazil. Given the pragmatic factors that emerge in such a context, mainly its communicative purpose, the study combines literature in Discourse Processing and in Cognitive Semantics to construe probable hypotheses that can account for the salience of repetitions in the political discourse under examination. Qualitative analysis renders repetition a linguistic-discursive strategy useful for the construction of arguments and for decreasing the cost of discourse processing. Therefore, a very useful strategy to reach, persuade, and convince the masses.

L'objectif de cette thèse était d‟étudier les processus d'activation et d'inhibition lexicales sous-tendant la lecture de mots et de déterminer le rôle du système affectif sur ces processus chez l'adulte. Pour cela, nous avons testé les effets de fréquence du voisinage orthographique et de l'émotionalité de ce voisinage dans plusieurs tâches cognitives. Les résultats ont montré un effet de fréquence du voisinage orthographique qui était inhibiteur dans des tâches de reconnaissance visuelle de mots (Expériences 1-4) et facilitateur dans des tâches de catégorisation de couleur de mots (Expériences 6-8). L'inhibition lexicale ralentirait la reconnaissance du mot stimulus et diminuerait ainsi son effet d'interférence dans des tâches de type Stroop. De plus, la valence et le niveau d'arousal du voisin plus fréquent modifiaient également la vitesse de reconnaissance du mot stimulus (Etude préliminaire, Expérience 1-5) et la catégorisation de sa couleur (Expériences 6, 7 et 9). Le système affectif s'activerait lors de la lecture de mots avec un voisin émotionnel et modifierait la propagation d'activation et d'inhibition lexico-émotionnelles. De plus, les résultats indiquaient que ces effets de voisinage orthographique étaient sensibles aux caractéristiques des participants. Une diminution de l'effet de fréquence du voisinage selon l'âge a été montrée et interprétée en termes de déficits conjoints d'activation et d'inhibition lexicales (Expériences 4, 5, 8 et 9). Enfin, l'effet du voisinage émotionnel obtenu suggérait une préservation des processus lexico-émotionnels avec l'avancée en âge (Expériences 4, 5 et 9), mais cet effet était corrélé négativement avec le niveau d'alexithymie des individus (Expériences 2, 4 et 6). Dans l'ensemble, ces données soulignent l‟importance de la prise en compte du système affectif dans les modèles de reconnaissance visuelle des mots
The aim of this thesis was to study lexical activation and inhibition processes underlying word reading and to determine the role of affective system on these processes in adults. For this, we investigated the effects of orthographic neighbourhood frequency and emotionality of this neighbourhood in several cognitive tasks. Results showed an orthographic neighbourhood frequency effect that was inhibitory in visual word recognition tasks (Experiments 1-4) and facilitatory in colour categorization tasks (Experiments 6-8). Lexical inhibition likely slows down the recognition of the stimulus word as well as diminishing its interference effect in Stroop-like tasks. Moreover, emotional valence and arousal level of the higher-frequency neighbour also modified the speed of stimulus word recognition (Preliminary study, Experiments 1-5) and its colour categorization (Experiments 6, 7 and 9). Thus, the affective system would be activated during reading of words with an emotional neighbour and would modify the spread of lexico-emotional activation and inhibition. Moreover, results indicated that these orthographic neighbourhood effects were sensitive to participants‟ characteristics. A decreaseof the orthographic neighbourhood effect depending on age was shown and interpreted in terms of deficits in both activation and inhibition processes (Experiments 4, 5, 8 and 9). Finally, the emotional neighbourhood effect that was obtained suggested a preservation of lexico-emotional processes with advance in age (Experiments 4, 5, and 9), but this effect was negatively correlated with individuals' level of alexithymia (Experiments 2, 4, and 6). Taken together, thes data underline the importance of taking the affective system into account in models of visual word recognition

碩士
國立中正大學
資訊工程研究所
100
Scene categorization acts as an essential part in many applications since scene type of an image provides abundant information for media analysis. Most works about scene categorization target on gray images, and rely on oriented gradient calculated based on intensity values as local descriptors. With these descriptors, the bag of word model is used in describing scene images. However, a visual word may be generated from different objects in various categories, and discriminative capability of visual words may hence decrease. On the other hand, exhaustive computation makes processes inefficient. In this thesis, we propose a fast scene categorization system to solve the problems mentioned above. We would like to study scene categorization for color images. We devise a new visual descriptor that incorporates color information into the framework of CENsus TRansform hISTogram (CENTRIST), a state-of-the-art visual descriptor for scene categorization. CENTRIST mainly encodes the structural properties within an image and suppresses detailed textural information. It is suitable to place and scene recognition task. Based on CENTRIST, we devise a new visual descriptor, i.e., color CENTRIST, that incorporates the advantage of CENTRIST and color information. The newly proposed color CENTRIST descriptor describes global shape information by not only gradient derived from intensity values but also color variations between pixels in local image patches. With color information, scenes of images can be effectively categorized. Through extensive evaluations on various datasets, we demonstrate that the color CENTRIST descriptor is not only easily to be implemented, but also reliably achieves performance over that of CENTRIST. Considering color information indeed benefits scene categorization.

博士
國立交通大學
電控工程研究所
102
With the popularity of internet in recent years, the usage of digital image is growing dramatically, which raises the trend of using image capture device. In order to allow users taking good photos with correct exposure in different scenes, the image capture device provides many scene modes such as scenery, beach…etc for user choosing. However, many scene modes complicate the function of digital cameras and users always feel inconvenient to switch the modes again and again. If a single mode can apply in different scenes, it would solve this inconvenience. The dissertation proposes a Scene Categorization System (SCS) with color cast correction, the preview image is applied into color cast detection, if judged by the color cast detection module with color cast, and the white balance module will depend on the suggestions to fine-tune image parameters to remove the color cast. After that, the image will be split into multiple image block units to extract each image block of the hue, saturation, brightness and contrast value and base on those characteristic values to estimate the shooting scene. Then the image capture device aperture value, shutter speed, and other parameters can be set up automatically. By the scene categorization system, the photographer is not necessary to take too much care with detailed camera settings and will be able to focus on composition.

碩士
國立雲林科技大學
工業設計系碩士班
92
The feeling from the color of a product is inseparable from its texture. This research aims to explore the people’s recognition on the features of color and texture and cognition effect, and furthermore explores whether the diversity in the users’ different backgrounds. The research analyzes the features of color and texture by the morphological analysis technique and simulates the plastic mice with different features combination. The method can find the better cause and effect explanation. Experiment 1, Free Will Categorization Experiment, explores recognition attitude of people on the constructive features of the mouse, and then finds out which feature or feature combination can be easily discriminated by users. Finally, we can confirm the cognition mode of people about the color and texture. Experiment 2, Semantic Different Experiment, explores which feature or feature combination effects users’ emotional feeling of color and texture on mouse. Through the results of the two experiments, we will understand the relationship between cognition and product features. Designers can vary colors and textures to create a product out looking which will be more appreciated by customers. Specific results are found from this research： 1.Color and texture’s categorization attitude from subjects’ different backgrounds－Designers frequently classify colors with the difference of hue, but non-designers classify colors with the difference of value in the categorization experiment. 2.Different results from different experiment tasks－We find out that the semantic different experiment can guide non-designers to evaluate vocabulary with noticeable value feelings, but designers evaluate vocabulary with various structure forms of noticeable value and transparency. 3.Different images feelings from different background subjects－They are affected by various structure forms of features. 4.Different results between color and form research with morphological analysis are affected by structures of features.

Propostas recentes no âmbito da cognição social situada sugerem que a cognição e comportamento humanos são influenciados por fatores contextuais. O objectivo principal do presente trabalho é examinar experimentalmente o impacto de um destes factores- a cor, no desempenho, nomeadamente em tarefas de decisão e categorização lexical. Em dois estudos experimentais, os participantes foram convidados a categorizar estímulos apresentados a vermelho, verde e cinzento (baseline). A manipulação da cor assentou no pressuposto geral de que a cor verde tenderia a acelerar o desempenho na categorização enquanto que a cor vermelha teria o efeito oposto. No primeiro estudo, os participantes decidiam se um conjunto de estímulos apresentados a vermelho, verde ou cinzento eram “palavras” ou “não-palavras”. Os resultados mostraram mais acertos e tempos de classificação mais rápidos quando os estímulos foram apresentadas a verde do que a vermelho. No segundo estudo os participantes categorizam palavras sinónimas de “avançar” ou “parar” e neutras, apresentadas a vermelho, verde ou cinzento. Tal como esperado, os participantes acertam mais em palavras de “parar” apresentadas a vermelho e em palavras de “avançar” apresentadas a verde. Foram ainda observados tempos de reação menores na classificação de palavras “parar” apresentadas a vermelho (vs. verde) e de palavras “avançar” apresentadas a verde. Em termos teóricos os resultados sugerem a influência contextual na cognição e comportamento humano dando suporte às propostas da cognição social situada. Os resultados poderão ainda informar possíveis aplicações organizacionais, educativas e sociais no que diz respeito à utilização da cor nos mais variados contextos.
Recent proposals in social cognition suggest that cognition and human behavior are influenced by contextual factors. This work aims to experimentally examine the impact of one of these factors- the color and how it affects performance, particularly in lexical decision and categorization tasks. In two experimental studies participants were asked to categorize stimuli presented in three different colors: red, green, and grey (baseline). The color manipulation was based on the general assumption that green would speed up the categorization performance while red would have the opposite effect. In the first study, participants decided whether a set of stimuli presented in red, green or grey were “words” or “non-words”. The results showed higher speed and accuracy rates when the stimuli were presented in green than in red. In the second study, participants categorized words that were synonyms of “go” and “stop” and neutral words. As expected, higher hit rates were observed for the “stop” words when they were presented in red, and for the “go” words when they were presented in green. Furthermore, we also observed that the reaction times were faster when the “stop” words were presented in red (vs. green), and the “go” words presented in green. Theoretically, the results suggest the contextual influence in cognition and human behavior, supporting the socially situated cognition proposals. Results are also likely to inform potential organizational, educational and social applications, regarding the use of color in the most varied contexts.

La présente thèse avait pour mandat d’examiner la question suivante : quels sont les indices visuels utilisés pour catégoriser le sexe d’un visage et comment sont-ils traités par le cerveau humain? La plupart des études examinant l’importance de certaines régions faciales pour la catégorisation du sexe des visages présentaient des limites quant à leur validité externe. L’article 1 visait à investiguer l’utilisation des indices achromatiques et chromatiques (sur l’axe xy) dans un contexte de plus grande validité externe. Pour ce faire, nous avons utilisé la technique Bubbles afin d’échantillonner l’espace xy de visages en couleurs n’ayant subi aucune transformation. Afin d’éviter les problèmes liés à la grande répétition des mêmes visages, nous avons utilisé un grand nombre de visages (c.-à-d. 300 visages caucasiens d’hommes et de femmes) et chaque visage n’a été présenté qu’une seule fois à chacun des 30 participants. Les résultats indiquent que la région des yeux et des sourcils—probablement dans le canal blanc-noir—est l’indice le plus important pour discriminer correctement le genre des visages; et que la région de la bouche—probablement dans le canal rouge-vert—est l’indice le plus important pour discriminer rapidement et correctement le genre des visages. Plusieurs études suggèrent qu’un indice facial que nous n’avons pas étudié dans l’article 1—les distances interattributs—est crucial à la catégorisation du sexe. L’étude de Taschereau et al. (2010) présente toutefois des données allant à l’encontre de cette hypothèse : les performances d’identification des visages étaient beaucoup plus faibles lorsque seules les distances interattributs réalistes étaient disponibles que lorsque toutes les autres informations faciales à l’exception des distances interattributs réalistes étaient disponibles. Quoi qu’il en soit, il est possible que la faible performance observée dans la condition où seules les distances interattributs étaient disponibles soit explicable non par une incapacité d’utiliser ces indices efficacement, mais plutôt par le peu d’information contenue dans ces indices. L’article 2 avait donc comme objectif principal d’évaluer l’efficacité—une mesure de performance qui compense pour la faiblesse de l’information disponible—des distances interattributs réalistes pour la catégorisation du sexe des visages chez 60 participants. Afin de maximiser la validité externe, les distances interattributs manipulées respectaient la distribution et la matrice de covariance observées dans un large échantillon de visages (N=515). Les résultats indiquent que les efficacités associées aux visages ne possédant que de l’information au niveau des distances interattributs sont un ordre de magnitude plus faibles que celles associées aux visages possédant toute l’information que possèdent normalement les visages sauf les distances interattributs et donnent le coup de grâce à l’hypothèse selon laquelle les distances interattributs seraient cuciale à la discrimination du sexe des visages. L’article 3 avait pour objectif principal de tester l’hypothèse formulée à la fin de l’article 1 suivant laquelle l’information chromatique dans la région de la bouche serait extraite très rapidement par le système visuel lors de la discrimination du sexe. Cent douze participants ont chacun complété 900 essais d’une tâche de discrimination du genre pendant laquelle l’information achromatique et chromatique des visages était échantillonnée spatiotemporellement avec la technique Bubbles. Les résultats d’une analyse présentée en Discussion seulement confirme l’utilisation rapide de l’information chromatique dans la région de la bouche. De plus, l’utilisation d’un échantillonnage spatiotemporel nous a permis de faire des analyses temps-fréquences desquelles a découlé une découverte intéressante quant aux mécanismes d’encodage des informations spatiales dans le temps. Il semblerait que l’information achromatique et chromatique à l’intérieur d’une même région faciale est échantillonnée à la même fréquence par le cerveau alors que les différentes parties du visage sont échantillonnées à des fréquences différentes (entre 6 et 10 Hz). Ce code fréquentiel est compatible avec certaines évidences électrophysiologiques récentes qui suggèrent que les parties de visages sont « multiplexées » par la fréquence d’oscillations transitoires synchronisées dans le cerveau.
In this thesis, we asked which face cues are used for gender discrimination and how they are processed by the humain brain. The few studies have tried to answer this question used only a small set of grayscale stimuli, often distorted and presented a large number of times. In Article 1, we reassessed the importance of chromatic and achromatic facial cues for gender categorisation in a more realistic setting. We used the Bubbles technique to sample the xy plane of a set of 300 color photographs of Caucasian faces, each presented only once to 30 participants. Results show that the region of the eyes and the eyebrows—probably in the light-dark channel—is the most important facial cue for accurate gender discrimination; and that the mouth region is also driving fast correct responses (but not fast incorrect responses)—the gender discrimination information in the mouth region is concentrated in the red-green color channel. Several studies suggest that a cue which we did not examine in Article 1—interattribute distances (e.g. the interpupil distance)—is critical for gender discrimination. A recent study by Taschereau-Dumouchel et al. (2010) challenged this idea by showing that participants were nearly at chance when asked to identify faces on the sole basis of real-word interattribute distances, while they were nearly perfect when all other facial cues were shown. However, it remains possible that humans are highly tuned to interattribute distances but that the information conveyed by these cues is scarce. In Article 2, we tested this hypothesis by contrasting the efficiencies—a measure of performance that factors out task difficulty—of 60 observers in six face-gender categorization tasks. Most importantly, efficiencies for faces that varied only in terms of their interattribute distances were an order of magnitude lower than efficiencies for faces that varied in all respects except their interattribute distances or in all respects. These results provide a definitive blow to the idea that real-world interattribute distances are critical for face gender categorization. In Article 3, we tested and confirmed the hypothesis formulated at the end of Article 1 according to which observers would rapidly extract chromatic information in the mouth region during sex categorization. One hundred and twelve participants each performed 900 trials of a face gender categorization task in which the achromatic and isoluminant chromatic content of faces were partially revealed in space and time with Bubbles. This experiment also allowed us to perform time-frequency analyses, which showed that achromatic and isoluminant chromatic information within the same facial part were sampled by the brain at the same frequency, whereas different facial parts were sampled at distinct frequencies (ranging from 6 to 10 Hz). This sampling code is consistent with recent electrophysiological evidence suggesting that facial features are multiplexed by the frequency of transient synchronized oscillations in the brain.

No
The bag of visual words (BOW) model is an efficient image representation technique for image categorization and annotation tasks. Building good visual vocabularies, from automatically extracted image feature vectors, produces discriminative visual words, which can improve the accuracy of image categorization tasks. Most approaches that use the BOW model in categorizing images ignore useful information that can be obtained from image classes to build visual vocabularies. Moreover, most BOW models use intensity features extracted from local regions and disregard colour information, which is an important characteristic of any natural scene image. In this paper, we show that integrating visual vocabularies generated from each image category improves the BOW image representation and improves accuracy in natural scene image classification. We use a keypoint density-based weighting method to combine the BOW representation with image colour information on a spatial pyramid layout. In addition, we show that visual vocabularies generated from training images of one scene image dataset can plausibly represent another scene image dataset on the same domain. This helps in reducing time and effort needed to build new visual vocabularies. The proposed approach is evaluated over three well-known scene classification datasets with 6, 8 and 15 scene categories, respectively, using 10-fold cross-validation. The experimental results, using support vector machines with histogram intersection kernel, show that the proposed approach outperforms baseline methods such as Gist features, rgbSIFT features and different configurations of the BOW model.

Przedłożona rozprawa doktorska zatytułowana Analiza łączliwości leksykalnej w ujęciu leksykograficznym (na przykładzie nazw barw w języku polskim i języku angielskim) jest pracą z zakresu językoznawstwa, a jej celem było poddanie analizie leksykalnej haseł słownikowych definiujących podstawowe nazwy barw w języku polskim oraz języku angielskim w celu ukazania sposobów konceptualizacji barw podstawowych w analizowanych językach. Przed przystąpieniem do badań empirycznych niezbędne było zapoznanie się z teorią koloru w ujęciu diachronicznym ze szczególnym uwzględnieniem ujęcia językoznawczego, następnie omówienie sposobów kategoryzacji barw w obydwu językach przez pryzmat nauk językoznawczych jak również innych, takich jak filozofia, historia sztuki czy fizyka, by następnie przejść do opisu leksykograficznego, na podstawie którego wyodrębnione zostały elementy mikrostruktury stanowiące przedmiot analizy leksykalnej.

THIS THESIS IS IN THE EXAMINATION PROCESS The ability to locate symbols on a visual display forms an integral part of the effective use of AAC systems. Characteristics of display design and perceptual features of symbols have been shown to influence rate and accuracy of symbol location (Thistle&Wilkinson, 2009; Wilkinson, Carlin,&Jagaroo, 2006). The current study endeavoured to compare the use of two colour-coded organisational strategies (alphabetical order and subcategorisation) for their effectiveness in symbol location and to investigate if some bottom-up features influenced the performance of the participants in these tasks. 114 learners in Grade 1 to 3 in a mainstream school were randomly divided into two groups. Both of the groups were exposed to two visual search tests in alternating order. The tests involved searching for 36 visual targets amongst 81 coloured Picture Communication Symbols on a computer screen in one of two colour-coded organizational methods, namely alphabetical order or subcategorisation. The data from the research task was collected through computer logging of all mouse selections. Findings showed that locating symbols on a computer screen with a subcategorisation strategy was significantly faster and more accurate than with an alphabetical strategy for the Grade 1 to 3 participants. The differences between the rates and accuracy of target symbol location using the two strategies decreased significantly as grade increased. It was also found that although the tests in this study placed heavy top-down processing demands on the participants, there was still evidence of bottom-up factors influencing their performance. Implications for display design in AAC clinical practice were discussed.
Thesis (PhD)--University of Pretoria, 2012.
Centre for Augmentative and Alternative Communication (CAAC)
Unrestricted