Tesis sobre el tema "Perceptual mapping"

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
A indústria hoteleira vem se desenvolvendo significativamente nos últimos anos impulsionada por grandes investimentos privados e do governo no setor de turismo e infraestrutura. Inteiramente vinculada à demanda turística e inserida no setor de serviços, a indústria apresenta um composto variável de bens e serviços, que requer o entendimento das necessidades e dos desejos de seus clientes para adotar as estratégias adequadas. Tal mercado é particularmente sensível à qualidade dos serviços prestados e produtos oferecidos aos hóspedes. A satisfação do consumidor é, portanto, um dos principais objetivos do setor, que busca criar valor para os seus clientes ao antecipar e gerenciar suas expectativas, sejam elas no segmento de turismo de lazer, sejam no segmento de turismo de negócios. Nesta pesquisa alguns atributos apontados como essenciais aos serviços de hotelaria foram utilizados com o objetivo de entender como o mercado percebe um conjunto de hotéis localizados na cidade do Rio de Janeiro. Para tanto, foi realizado um estudo em que se empregou análise de correspondência para desenhar o mapa de percepções relativo a um conjunto pré-definido de atributos e hotéis. O mapa bidimensional indica prevalência dos atributos área de lazer e valor para a dimensão I e de um conjunto de atributos mais voltados para o segmento de negócios no caso da dimensão II, onde localização e restaurante são destaques positivos e qualidade do quarto e limpeza têm relevo negativo. O Othon Palace enfatiza os dois segmentos (as duas dimensões). O hotel Pestana Rio Atlântica prioriza o turismo lazer, enquanto que os outros oito hotéis pesquisados estão mais concentrados em torno da origem (coordenadas normalizadas com valor absoluto inferior a 0,4), o que caracteriza um posicionamento estratégico ambíguo, buscando privilegiar tanto o turismo de negócios quanto o de lazer.
The hotel industry has been developing significantly in the last years, driven by large public and private investments in the tourism and infrastructure sectors. Said industry is entirely related to the demand of tourism activity and is inserted in the service sector. Additionally, it is made up of a variable of good and services, which requires the understanding of the needs and wants of its clients in order to adopt the adequate strategies. Such a market is particularly sensitive to the quality of services rendered as well as to products offered to guests. Therefore, customer satisfaction is one of the main objectives of the sector that strives to create value for its clients by anticipating and managing their expectations, be them in the leisure or business tourism segments. In this research some attributes considered to be essential to the services of the hotel industry were used with the purpose of understanding how the market perceives a group of hotels located in the City of Rio de Janeiro. To this effect, a study was done in which correspondence analysis was implemented to conceptualize the perceptions map concerning a group of predefined attributes and hotels. The bi-dimensional map indicates mostly leisure attributes and value to the Dimension I and a group of attributes pertaining to the business segment in the Dimension II, where location and restaurant stand out as positive factors and room quality and cleanliness have a negative relevance. Othon Palace hotel emphasizes the two segments (the two dimensions). Pestana Rio Atlântica hotel prioritizes leisure tourism, while the other eight hotels that were analyzed are more concentrated due to their origin (normalized coordinates with an absolute value inferior to 0.4), which characterizes an ambiguous strategic positioning, striving to excel both in leisure and business tourism.

This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 51-53).
Product perceptual maps are visualizations of the perceptions of products by customers. They provide many advantages to businesses, such as identifying gaps in the market, understanding competition, and finding how new products fit into a market. Conventional product perceptual mapping methods exhibit limitations, particularly in capturing the highly nonlinear structure in product perceptual categories. Therefore, given only a set of images and triplet data representing product co-occurence by consumers, we propose and use a Gaussian mixture variational autoencoder (GMVAE) with triplet loss to create product embeddings. These product embeddings are then flattened into a 2D perceptual map able to be interpreted by human judgment. We test the GMVAE approach on three datasets: (1) a dataset of simple generated data; (2) the MNIST dataset, a dataset of handwritten digits; and (3) the Amazon Fashion dataset, a dataset of product images, product categories, and similar products. The GMVAE method is quantitatively evaluated on its ability to capture product "latent" categories, and qualitatively evaluated on the quality of its 2D perceptual maps compared with those produced by using a conventional perceptual mapping method. We find that across the experiments, the GMVAE method could reasonable capture "latent" perceptual product categories and is more effective than the conventional perceptual mapping baseline in correctly identifying and predicting latent product categories.
by Mike Wang.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

Regional differences in sweat gland output, skin temperature and thermoreceptor distribution can account for variations in regional perceptions of temperature, thermal comfort and wetness sensation. Large cohorts of studies have assessed these perceptual responses during sedentary activity but the findings are typically applied to a multitude of conditions, including exercise. Increases in sweat gland output, redistribution of blood flow and changes in skin and core temperature are basic responses to exercise in most conditions and these ultimately influence our perceptual responses. The primary aim of this thesis is to determine factors that influence regional differences in thermal sensation, thermal comfort and wetness sensation during exercise in moderate to hot conditions. The secondary aim is to develop and understand an additional variable, galvanic skin conductance (GSC) that can be used to predict thermal comfort and wetness sensation. The aim of the first study (Chapter 4) was to determine the influence of exercise on thermal sensitivity and magnitude sensation of warmth to a hot-dry stimulus (thermal probe at 40°C) and assess if any gender-linked differences and/or regional differences exist. From the data, body maps indicating sensitivity were produced for both genders during rest and exercise. Females had more regional differences than males. Overall sensitivity was greatest at the head, then the torso and declined towards the extremities. The data showed that exercise did not cause a significant reduction in thermal sensitivity but magnitude estimation was significantly lower after exercise for males and selected locations in females. The cause of a reduced magnitude sensation is thought to be associated with exercise induced analgesia; a reduction in sensitivity due to exercise related increases in circulating hormones. As the literature suggests that thermal comfort in the heat is influenced by the presence of sweat, the next study and all proceeding studies were concerned with this concept. In Chapter 5, building on earlier studies performed in our laboratories, the influence of local skin wettedness (wlocal) on local thermal comfort and wetness sensation was investigated in a neutral dry condition (20.2 ± 0.5°C and 43.5 ± 4.5% RH) whilst walking (4.5 km∙hr-1). Regional differences in wlocal were manipulated using specialised clothing comprising permeable and impermeable material areas. Strong correlations existed between local thermal comfort and local wetness sensation with the various measured wlocal (r2>0.88, p<0.05 and r2>0.83, p<0.05, respectively). The thermal comfort limit was defined as the wlocal value at which the participants no longer felt comfortable. Regional comfort limits for wlocal were identified (in order of high-low sensitivity); lower back (0.40), upper legs (0.44), lower legs (0.45), abdomen (0.45), chest (0.55), upper back (0.56), upper arms (0.57) and lower arms (0.65). The maximum degree of discomfort and wetness sensation experienced during the investigation was kept deliberately low in an attempt to determine the threshold values. Therefore comfort scores and wetness scores rarely reached a state of uncomfortable or wet so the next step was to assess these relationships when sweat production is high and the sensations worsened. However, pilot testing indicated that a ceiling effect would occur for wlocal at high levels of sweat production whilst thermal discomfort increased indicating wlocal was not the determining parameter in that case. Thus an additional parameter was required. The chosen parameter was galvanic skin conductance (GSC) due to its alleged ability to monitor pre-secretory sweat gland activity, skin hydration and surface sweat. In Chapter 6, the reliability, reproducibility and validity of GSC were confirmed in a series of pilot tests. Moderate to strong correlations were found between GSC and regional sweat rate (RSR) (r2>0.60, p<0.05) and wlocal (r2>0.55, p<0.05). The literature suggests standardising GSC relative to a minimum and maximum GSC value; however uncertainties arise when attempting to achieve maximum GSC. Therefore a change from baseline (∆GSC) was chosen as the proposed method of standardisation for further use. Additional results (from Chapter 9) revealed that ∆GSC also reflects pre-secretory sweat gland activity as it increased prior to sweat being present on the skin surface and prior to an increase in RSR. In Chapter 9, also hydration of the stratum corneum was measured using a moisture meter and the results revealed that it has an upper limit; indicating maximal hydration. From this point of full skin saturation ∆GSC and RSR markedly increase though sensations did not. It was also found that ∆GSC is only influenced by surface sweat that is in direct contact with the electrode and is not influenced by sweat elsewhere on the skin surface between electrodes. Higher levels of thermal discomfort have rarely been explored and neither has its relationship with wlocal. The ability of ∆GSC and wlocal to predict local thermal comfort and wetness sensation were compared in two different conditions to elicit low and high sweat production. Unlike Chapter 5, the body sites were not manipulated to control wlocal but allowed to vary naturally over time. The test was carried out on males (Chapter 7) and females (Chapter 8) to compare any gender linked differences and the results suggest that females are more sensitive than males to the initial presence of sweat. For both genders, wlocal and ∆GSC are strong predictors of thermal comfort and wetness sensation. More importantly, wlocal can only be used to predict local thermal comfort in conditions of low sweat production or low levels of thermal discomfort. However, once sweat production increases and thermal discomfort worsens ΔGSC (and not wlocal) can predict thermal comfort. Due to low sweat production observed in females indicates that this is only relevant for females. It appears that epidermal hydration has an important role on influencing thermal comfort. Receptors influencing our perceptual responses are located in the epidermis and when sweat is produced and released onto the skin surface, this epidermis swells and the sensitivity of receptors are said to increase. wlocal indicates the amount of moisture present on the skin surface, yet ∆GSC indicates presecretory sweat gland activity and epidermal hydration where the receptors are located. This may explain why on numerous occasions thermal comfort had a stronger relationship with ∆GSC than wlocal. Where Chapter 5 indicated the true local comfort limits for each respective zone, Chapter 7 and 8 provided a global picture of how local regions interact and influence local thermal comfort across the body. When wlocal varies naturally, the torso areas naturally produce more sweat than the extremities and it seemed that these areas produce so much more sweat than the extremities that they dominate local thermal comfort across the whole body. This is referred to in this thesis as a model of segmental interaction. As with thermal comfort, wetness sensation had strong relationships with wlocal and ∆GSC. The results also revealed a strong relationship between wetness sensation and thermal comfort. In contrast to the widely supported claim, a drop in skin temperature is not required to stimulate a wetness sensation. The point at which we detect sweat and when it becomes uncomfortable occurs at different wlocal values across the body. Thermal comfort is shown to be influenced by sweat during exercise in moderate-to-hot conditions. As w has an upper limit the findings suggest that it cannot predict thermal comfort during high sweat rates. Galvanic skin conductance monitors the process of sweat production more closely and thus is a better predictor of thermal comfort during all conditions and particularly during high sweat production. The strong relationship between thermal comfort and wetness sensation confirm the role of sweat production on thermal comfort. Gender differences to perceptual responses were observed, with females generally being more sensitive to sweat and a warm thermal stimulus than males. Regional differences to sweat and a warm stimulus generally suggest that the torso area is more sensitive than the extremities. This is important not only for sports clothing design but also protective clothing at the work place.

Perceptual dialectology studies have shown that people have strong opinions about the number and placement of dialect regions. There has been relatively little research conducted in this area on Korean, however, with early studies using only short language attitude surveys. To address this gap in research, in the present study, I use the 'draw-­?a-­?map' task to examine perceptions of language variation in Korea. I ask respondents to draw a line around places in Korea where people speak differently and provide names, examples, and comments about the language spoken in those areas. With the resulting data, I use ArcGIS 10.0 software to quantitatively identify, aggregate, and map the most salient dialect areas and categories for subjects' perceptions. I also perform a content analysis of the qualitative data provided by respondents using 'keywords.' During this process, I categorize comments and labels given by respondents to find emerging themes. Finally, I stratify perceptions of respondents by demographic factors, e.g., age, sex, and urbanicity, that have often been found to be important in language variation and change. An analysis of these data suggests that Koreans' perceptions of dialect regions are not necessarily limited by administrative boundaries. In fact, the data reveal not only perceptions of dialect variation unassociated with geographic borders, but they also tap into the way people connect ideas about language and place. Results from this study have implications for language attitudes research, perceptual dialectology methodology, and the relationship between language and place in Korea.

Public Health
Ph.D.
The rate at which women choose mastectomy has grown dramatically, and of particular note is the increase in contralateral prophylactic mastectomy (CPM). For women with no history of breast cancer or genetic risk, CPM represents a treatment decision that does not offer better long-term outcomes than the decision not to remove a healthy breast and may be associated with increased surgical risk and interventions, increased cost to the healthcare system, and potential adverse psycho-social outcomes. To better understand the decision making process regarding the election of CPM among women with early stage unilateral breast cancer, with no family history or genetic risk, a three-phase exploratory study was conducted. Qualitative in-depth interviews were conducted with healthcare providers who have close interaction with women during the decision making process (N=3) and patients who made a surgical decision about breast cancer treatment within the past three years (N=11). These two phases informed the design of the quantitative internet survey, conducted among women diagnosed with early stage breast cancer in the process of making a surgical decision (N=336). The survey design was also guided by an existing model for treatment decision making which uses a social ecological framework (Revenson & Pranikoff, 2005). In addition to descriptive analyses, perceptual mapping was utilized to understand patients’ conceptualizations of the relative importance of factors considered during the decision making process, and AdSAM® was used to gauge emotional response. Results suggest that women more likely to elect CPM demonstrate an emotional response to a generalized fear of cancer, along with the need to take control of their situation. In addition, retrospective interviews emphasized somewhat different reasons for electing CPM, highlighting the importance of prospective research in studying the decision making process.
Temple University--Theses

This thesis is concerned with maximizing the coding efficiency, random accessibility and visual performance of scalable compressed video. The unifying theme behind this work is the use of finely embedded localized coding structures, which govern the extent to which these goals may be jointly achieved. The first part focuses on scalable volumetric image compression. We investigate 3D transform and coding techniques which exploit inter-slice statistical redundancies without compromising slice accessibility. Our study shows that the motion-compensated temporal discrete wavelet transform (MC-TDWT) practically achieves an upper bound to the compression efficiency of slice transforms. From a video coding perspective, we find that most of the coding gain is attributed to offsetting the learning penalty in adaptive arithmetic coding through 3D code-block extension, rather than inter-frame context modelling. The second aspect of this thesis examines random accessibility. Accessibility refers to the ease with which a region of interest is accessed (subband samples needed for reconstruction are retrieved) from a compressed video bitstream, subject to spatiotemporal code-block constraints. We investigate the fundamental implications of motion compensation for random access efficiency and the compression performance of scalable interactive video. We demonstrate that inclusion of motion compensation operators within the lifting steps of a temporal subband transform incurs a random access penalty which depends on the characteristics of the motion field. The final aspect of this thesis aims to minimize the perceptual impact of visible distortion in scalable reconstructed video. We present a visual optimization strategy based on distortion scaling which raises the distortion-length slope of perceptually significant samples. This alters the codestream embedding order during post-compression rate-distortion optimization, thus allowing visually sensitive sites to be encoded with higher fidelity at a given bit-rate. For visual sensitivity analysis, we propose a contrast perception model that incorporates an adaptive masking slope. This versatile feature provides a context which models perceptual significance. It enables scene structures that otherwise suffer significant degradation to be preserved at lower bit-rates. The novelty in our approach derives from a set of "perceptual mappings" which account for quantization noise shaping effects induced by motion-compensated temporal synthesis. The proposed technique reduces wavelet compression artefacts and improves the perceptual quality of video.

Public Health
Ph.D.
School-based body mass index (BMI) screenings seek can improve parents' recall about their child's weight, increase concern about excess weight, and correct parents' misperceptions to help them make informed decisions about their child's health. However, schools have questioned parents' understanding of and attitudes about BMI, and have expressed concern about parents' reactions to BMI reports. Using a sample of school nurses (n=7) and parents/guardians (n=125) from the School District of Philadelphia (SDP), this research addressed these concerns by clarifying: 1) parents'/guardians' perceptions and knowledge about BMI; 2) the challenges schools face in communicating with parents/guardians; and 3) the messages that can be communicated to parents/guardians to help them understand their child's BMI-for-age category and why their child's BMI is measured in his/her school. The research used framing theory and perceptual mapping methods to study and improve communication about BMI to parents/guardians in the School District. The four-phase study design incorporated qualitative (focus groups and semi-structured in-depth interviews) and quantitative (cross-sectional survey) methods to assist in the development of an evidence-informed BMI report card template for the SDP. Messages were constructed to meet the needs of four distinct groups of parents/guardians that emerged from the factor and cluster analyses - "Passive Parents," "Neutral Parents," "Confident Advocates" and "Active Worriers." Although each cluster of parents/guardians had their own unique perceptions and varying degrees of assuredness and confidence related to BMI concepts, the majority of parents/guardians in this study shared common favorable perceptions about BMI measures, school-based screening programs and BMI report cards.
Temple University--Theses

The cinema and television industries are continuously working in the development of image features that can provide a better visual experience to viewers; these image attributes include large spatial resolution, high temporal resolution (frame rate), greater contrast, and recently, with emerging display technologies, much wider color gamut. The gamut of a device is the set of colors that this device is capable of reproducing. Gamut Mapping Algorithms (GMAs) transform colors of the original content to the color palette of the display device with the simultaneous goals of (a) reproducing content accurately while preserving the artistic intent of the original content’s creator and (b) exploiting the full color rendering potential of the target display device. There are two types of gamut mapping: Gamut Reduction (GR) and Gamut Extension (GE). GR involves the transformation of colors from a larger source gamut to a smaller destination gamut. Whereas in GE, colors are mapped from a smaller source gamut to a larger destination gamut. In this thesis we propose three spatial Gamut Reduction Algorithms (GRAs) and four spatial Gamut Extension Algorithms (GEAs). These methods comply with some basic global and local perceptual properties of human vision, producing state of the art results that appear natural and are perceptually faithful to the original material. Moreover, we present a psychophysical evaluation of GEAs specifically for cinema using a digital cinema projector under cinematic (low ambient light) conditions; to the best of our knowledge this is the first evaluation of this kind reported in the literature. We also show how currently available image quality metrics, when applied to the gamut extension problem, provide results that do not correlate well with users’ choices.
Les indústries de cinema i televisió estan treballant contínuament en el desenvolupament de diferents característiques de la imatge que puguin proporcionar una millor experiència visual per als espectadors; aquests atributs d’imatge inclouen la resolució espacial, la resolució temporal (fotogrames per segon), major contrast i, recentment, amb les noves tecnologies de visualització emergents, una gamma de colors (gamut) molt més ampli. El gamut d’un dispositiu és el conjunt de colors que aquest dispositiu és capaç de reproduir. Els algoritmes de modificació de gamut (GMA, de les seves sigles en anglés) transformen els colors del contingut original a la paleta de color del dispositiu de visualització amb els objectius de (a) reproduir el contingut amb precisió preservant al mateix temps la intenció artística del creador del contingut original i (b) utilitzar tot el gamut de color del dispositiu de visualització. Hi ha dos tipus d’algoritmes de modificació de gamut: Reducció de Gamut (GR) i Extensió de Gamut (GE). GR implica la transformació dels colors d’un gamut d’origen més gran a un gamut de destinació més petit. Mentre que a GE, els colors s’assignen d’un gamut d’origen petit a un gamut de destinació més gran. En aquesta tesi es proposen tres algoritmes de Reducció de Gamut (GRAs) i quatre algoritmes d’extensió de Gamut (GEAs). Aquests mètodes compleixen amb algunes propietats perceptives globals i locals bàsiques de la visió humana, produint resultats que són estat de l’art, i que són naturals i perceptualment fidels al material original. D’altra banda, es presenta una avaluació psicofísica del problema d’extensió de Gamut específicament dissenyada per a cinema utilitzant un projector de cinema digital en condicions cinemàtiques (baixa llum ambiental); aquest estudi creiem que és el primer del seu tipus a la literatura. També mostrem com les mètriques de qualitat d’imatge disponibles actualment proporcionen resultats que no es correlacionen bé amb l’elecció dels usuaris quan s’apliquen al problema d’Extensió de Gamut.

Le système de gestion de couleur vise à réaliser la reproduction cohérente de contenus visuels à travers une chaîne de reproduction avec des médias différents. C'est un domaine de recherche pluridisciplinaire qui implique les sciences de la couleur, de la vision et les techniques de traitement d'image. Actuellement, le modèle de reproduction CMS apparait comme la solution la plus acceptée. La plupart des solutions sont basées sur le Consortium International de Couleurs (ICC) version 4 dont les recommandations sur les modes de rendu sont principalement basées sur la science des couleurs et n’intègre pas d’analyse fine du contenu de l'image. Cela conduit inévitablement à une ambigüité au niveau de la sélection des modes de rendu et la faiblesse quant à la préservation des détails dans l’image. Pour répondre à ces insuffisances, le concept d’évaluation de la qualité d'image (IQA) est introduit dans le CMS. L’idée est alors de réduire le gamut en analysant l’image localement. Cela permet ainsi de faire le meilleur choix des modes de rendu. Une contribution importante dans ce travail consiste à introduire quelques algorithmes d’amélioration de l’apparence visuelle de l'image en s’appuyant sur les solutions de CMS existantes tout en tenant compte des caractéristiques de l'appareil. Cette stratégie permet d’améliorer considérablement le rendu global tout en préservant les détails de l'image
Color Management System (CMS) aims to realize coherent reproduction through a cross-media chain. It is a joint-domain issue which involves color science, vision science and image processing. Nowadays, pleasant reproduction of CMS draws increasing concern as well. Most of the state-of-the-art solutions are based on the International Color Consortium (ICC) standard Version 4 whose recommendations on rendering intents are mainly based on color science and unaware of image contents. This leads to ambiguity of rendering intents selection and insufficient detail retaining in real practice. Targeting these insufficiencies, the concept of Image Quality Assessment (IQA) is introduced into CMS by the proposed Image Gamut Boundary Reduction (IGBR) operation to enable more reasonable rendering intents selection based on image content analysis. More importantly, several natural color image enhancement algorithms are developed and integrated into the existing CMS solutions with consideration of device characteristics which dramatically improves the global pleasantness and detail retaining of the image reproduction

L'un des buts principaux de l'imagerie numérique est d'une part la capture et d'autre part la reproduction de scènes réelles ou synthétiques sur des dispositifs d'affichage aux capacités restreintes. Les techniques d'imagerie traditionnelles sont limitées par la gamme de luminance qu'elles peuvent capturer et afficher. L'imagerie à grande gamme de luminance (High Dynamic Range – HDR) vise à dépasser cette limitation en capturant, représentant et affichant les quantités physique de la lumière présente dans une scène. Cependant, les technologies d'affichage existantes ne vont pas disparaitre instantanément, la compatibilité entre ces nouveaux contenus HDR et les contenus classiques est donc requise. Cette compatibilité est assurée par une opération de réduction des gammes de luminance (tone mapping) qui adapte les contenus HDR aux capacités restreintes des écrans. Bien que de nombreux opérateurs de tone mapping existent, ceux-ci se focalisent principalement sur les images fixes. Les verrous scientifiques associés au tone mapping de vidéo HDR sont plus complexes du fait de la dimension temporelle. Les travaux recherche menés dans la thèse se sont focalisés sur la préservation de la cohérence temporelle du vidéo tone mapping. Deux principaux axes de recherche ont été traités : la qualité subjective de contenus tone mappés et l'efficacité de la compression des vidéos HDR. En effet, tone mapper individuellement chaque image d'une séquence vidéo HDR engendre des artefacts temporels. Ces artefacts affectent la qualité visuelle de la vidéo tone mappée et il est donc nécessaire de les minimiser. Au travers de tests effectués sur des vidéos HDR avec différents opérateurs de tone mapping, nous avons proposé une classification des artefacts temporels en six catégories. Après avoir testé les opérateurs de tone mapping vidéo existants sur les différents types d'artefacts temporels, nous avons observé que seulement trois des six types d'artefacts étaient résolus. Nous avons donc créé une technique de post-traitement qui permet de réduire les 3 types d'artefacts non-considérés. Le deuxième aspect considéré dans la thèse concerne les relations entre compression et tone mapping. Jusque là, les travaux effectués sur le tone mapping et la vidéo compression se focalisaient sur l'optimisation du tone mapping de manière à atteindre des taux de compression élevés. Ces techniques modifient fortement le rendu, c'est à dire l'aspect de la vidéo, modifiant ainsi l'intention artistique initiale en amont dans la chaine de distribution (avant la compression). Dans ce contexte, nous avons proposé une technique qui permet de réduire l'entropie d'une vidéo tone mappée sans en modifier son rendu. Notre méthode adapte la quantification afin d'accroitre les corrélations entre images successives d'une vidéo
One of the main goals of digital imagery is to improve the capture and the reproduction of real or synthetic scenes on display devices with restricted capabilities. Standard imagery techniques are limited with respect to the dynamic range that they can capture and reproduce. High Dynamic Range (HDR) imagery aims at overcoming these limitations by capturing, representing and displaying the physical value of light measured in a scene. However, current commercial displays will not vanish instantly hence backward compatibility between HDR content and those displays is required. This compatibility is ensured through an operation called tone mapping that retargets the dynamic range of HDR content to the restricted dynamic range of a display device. Although many tone mapping operators exist, they focus mostly on still images. The challenges of tone mapping HDR videos are more complex than those of still images since the temporal dimensions is added. In this work, the focus was on the preservation of temporal coherency when performing video tone mapping. Two main research avenues are investigated: the subjective quality of tone mapped video content and their compression efficiency. Indeed, tone mapping independently each frame of a video sequence leads to temporal artifacts. Those artifacts impair the visual quality of the tone mapped video sequence and need to be reduced. Through experimentations with HDR videos and Tone Mapping Operators (TMOs), we categorized temporal artifacts into six categories. We tested video tone mapping operators (techniques that take into account more than a single frame) on the different types of temporal artifact and we observed that they could handle only three out of the six types. Consequently, we designed a post-processing technique that adapts to any tone mapping operator and reduces the three types of artifact not dealt with. A subjective evaluation reported that our technique always preserves or increases the subjective quality of tone mapped content for the sequences and TMOs tested. The second topic investigated was the compression of tone mapped video content. So far, work on tone mapping and video compression focused on optimizing a tone map curve to achieve high compression ratio. These techniques changed the rendering of the video to reduce its entropy hence removing any artistic intent or constraint on the final results. That is why, we proposed a technique that reduces the entropy of a tone mapped video without altering its rendering

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A questão do posicionamento de marcas é central ao processo de gerenciamento de marketing, pois produtos e serviços são adquiridos em grande parte em função da imagem que constroem na mente dos consumidores e clientes. Este trabalho busca explorar as relações existentes entre posicionamento de marca, preferências dos indivíduos e comportamento de compra através do tempo. Mais especificamente, ele se propõe a examinar as relações entre distância de uma marca ao ponto ideal num mapa perceptual e sua participação de mercado, e o quanto mudanças nessa distância através do tempo são acompanhadas de ganhos ou perdas de participação de mercado. Nessa tarefa são utilizadas técnicas de análise multivariada como o escalonamento multidimensional, a fim de elaborar os mapas perceptuais, e o mapeamento de preferências, a fim de localizar pontos ideiais nos mapas elaboradas. Também é utilizada a técnica de análise procrusteana, no processo de comparação de diferentes mapas perceptuais. Uma vez determinadas as distâncias das marcas ao ponto ideal e suas variações entre dois momentos no tempo, tais medidas são correlacionadas às participações de mercado das marcas, e suas variações. Os resultados obtidos no estudo empírico indicam que a variável 'distância ao ponto ideal no mapa perceptual' é boa candidata a um indicador de participação de mercado, presente e futura. No entanto, esta distância não se mostra um bom indicador das variações na participação de mercado propriamente ditas. Outro resultado interessante diz respeito ao conceito de equilíbrio entre a ordenação das marcas em função das distâncias ao ponto ideal e ordenação das marcas em função da participação de mercado, sugerindo que quando existe uma discordância nestas ordens, as participações de mercado das mrcas tendem a mudar na direção de reduzir este desequilíbrio.
The matter of brand positioning is central to the process of marketing management, as products and services are purchased a great deal due to the image they build in consumers and clients minds. This work aims to explore the relationships that exist between brand positioning, subject’s preferences and buying behavior across a period of time. More specifically, it proposes itself to examine the relationships between distance of a brand to the ideal point in a perceptual map and its market share, and to what extent changes in the distance of the brand to the ideal point are followed by gains or losses in market share. In this task, multivariate analysis techniques are employed, such as multidimensional scaling, in order to build the perceptual maps, and preference mapping, in order to determine the location of ideal points in the maps. Procrustean analysis is also employed in the process of comparing individual maps to each other. Once determined the distances of brands to the ideal point and its changes across two points in time, these measures are compared to the market share of these brands, and its changes. The results from the empirical study indicate that the variable “distance to the ideal point in a perceptual map” is a good indicator of market share, present and future. However, this distance does not represent a good indicator of the market share changes themselves. Another interesting result relates to the concept of equilibrium between ordering of brands according to distances to the ideal point, and ordering of brands according to market share, suggesting that, when there is disagreement between these two orderings, the market share of the brands tend to shift towards a reduction of this disequilibrium.

Design fixation is a phenomenon experienced by professional designers and engineering design students that stifles creativity and innovation through discouraging ideational productivity, fluency and diversity. During the design idea and concept generation phase of the design process, a reliance on perceptual surface feature similarities between design artefacts increases the likelihood of design fixation leading to design duplication. Psychologists, educators and designers have become increasingly interested in creative idea generation processes that encourage innovation and entrepreneurial outcomes. However, there is a notable lack of collaborative research between psychology, education and engineering design particularly on inductive reasoning of undergraduate engineering students in higher education. The data gathered and analysed for this study provides an insight into property inference decision-making preferences and decision switching (SWITCH) patterns of engineering undergraduates under similarity-based inductive judgements [SIM] and category-based inductive judgements [CAT]. For this psychology experiment, property induction tasks were devised using abstract shapes in a triad configuration. Participants (N = 180), on an undergraduate engineering programme in London, observed a triad of shapes with a target shape more similar-looking to one of two given shapes. Factors manipulated for this experiment included category alignment, category group, property type and target shape. Despite the cognitive development and maturation stage of undergraduate engineers (adults) in higher education, this study identified similarity-based inductive judgements [SIM] to play a significant role during inductive reasoning relative to the strength of category-based inductive judgements [CAT]. In addition to revealing the property inference decision-making preferences of a sample of undergraduate engineers (N = 180), two types of switch classification and two types of non-switch classification (SWITCH) were found and named SIM_NCC, SIM-Salient, Reverse_CAT and CAT_Switching. These different classifications for property inference switching and non-switching presented a more complex pattern of decision-making driven by the relative strength between similarity-based inductive judgements [SIM] and category-based inductive judgements [CAT]. The conditions that encouraged CAT_Switching is of particular interest to design because it corresponds to inference decision switching that affirms the sharing of properties between dissimilar-looking shapes designated as category members, i.e., in a conflicting category alignment condition (CoC). For CAT_Switching, this study found a significant interaction between a particular set of conditions that significantly increased the likelihood of property inference decisions switching to affirm the sharing of properties between dissimilar-looking shapes. Stimuli conditions that combined a conflicting category alignment condition (where dissimilar-looking shapes belong to the same category) with category specificity, a causal property and a target shape with merged (or blended) perceptual surface features significantly increased the likelihood of a property inference decision switching. CAT_Switching has important implications for greater ideational productivity, fluency and diversity to discourage design fixation within the conceptual design space. CAT_Switching conditions could encourage more creative design transformations with alternative design functions through inductive inferences that generalise between dissimilar artefact designs. The findings from this study led to proposing a Cartesian view of the concept design space to represent the possibilities for greater movements through flexible and expanding category boundaries to encourage conceptual combinations, greater ideational fluency and greater ideational diversity within a configuration design space. This study has also created a platform for further research into property inference decision-making, ideational diversity and category boundary flexibility under stimuli conditions that encourage designers and design students to make inductive generalisations between dissimilar domains of knowledge through a greater emphasis on causal relations and semantic networks.

碩士
國立成功大學
資訊工程學系碩博士班
101
High-Dynamic Range images have a span widely radiances, so the HDR images are not displayable in a regular Low-Dynamic Range monitors. The common solution of this problem is called Tone Mapping. Tone mapping can compress the HDR images into the LDR images with distortion. A good tone mapping operator should reproduce the original scene realistically instead of damaging the original images to obtain the exaggerate results. We propose our method in two stages. The first stage is a global perceptual-based tone mapping operator that implements the Naka-Rushton equation to do visual adaptation and preserves the detail of the brightness region. The second stage is to implement the Guided Image Filter to analyze local detail enhancement methods in order to avoid halos artifact and reduce the distortion rate efficiently. Focusing on distortion, we evaluate both two stages of our method with metric validated by psychophysical experiments, the distortion rate of two stages outperform the state of the art.

碩士
國立暨南國際大學
資訊管理學系
99
Despite travel products are one of the most popular items in online shopping market, the tourism market competition is still intense. The successful tourism business must simultaneously manage physical and Internet channels. Therefore, the dual channel mode (hybrid travel agency) is common in the tourism industry. Travel agency managers should pay more attention to the competition and market position issues on these two channel-dimensions. Market positioning analysis using perceptual mapping is generally used for analyzing consumers and markets. This study focuses on market positioning analysis of online travel agencies in Taiwan based on consumers' perceptual mapping and uses multidimensional scaling (MDS) to identify the perceptual maps of relative positions of the main nine travel websites in the perception of the customer. Empirical data were collected from Taiwanese who had purchased travel goods. A total of 951 Taiwan respondents participated in this study. The results of multidimensional scaling analyses show that the customer perceptions of some travel websites are very close in the perceptual map. This may mean that they are highly competitive. But some travel websites have unique service positions that are not strongly associated with other travel websites in the perceptual maps. This research result will to provide management-related references for hybrid travel agency managers.

碩士
朝陽科技大學
企業管理系
104
In recent years, with the rapid technological development and the raise of economic and national income, consumers’ demand of household electric appliances has changed from luxury to indispensable necessities. As the demand of household electric appliances increases, the industry of household electric appliances has developed. The people’ life has closely lived with household electric appliances. The industry of household electric appliances in Taiwan has been more than seventy years. Tatung, which has the longest history, is not only durable and economical but also the love and the miss to hometown, Taiwan, to the students abroad and the consumers in 1950s and 1960s. After Taiwan became the member of the WTO, brands of imported appliance begin to march into Taiwan. This situation is a major threat to Tatung and the Panasonic, from Japan, and LG, from Korea all have occupied considerable degree of market size in Taiwan. Tatung must need to make some transformation and change. This research wants to understand Taiwan consumers’viewpoints to Tatung by the questionnaire. The empirical result shows that different interviewee has different evaluation to Tatung, Panasonic and LG. The interviewees’ evaluation to Tatung will positively affect brand loyalty. And then, through the Importance Performance Analysis( IPA), we know that Tatung should improve the two services, “function” and “after-sales service” respectively. Keywords: brand loyalty, product attributes,I mportance Performance Analysis, perceptual map

Tone mapping operators aim to compress high dynamic range (HDR) images to low dynamic range ones so as to visualize HDR images on standard displays. Most existing works were demonstrated on specific examples without being thoroughly tested on well-established and subject-validated image quality assessment models. A recent tone mapped image quality index (TMQI) made the first attempt on objective quality assessment of tone mapped images. TMQI consists of two fundamental building blocks: structural fidelity and statistical naturalness. In this thesis, we propose an enhanced tone mapped image quality index (eTMQI) by 1) constructing an improved nonlinear mapping function to better account for the local contrast visibility of HDR images and 2) developing an image dependent statistical naturalness model to quantify the unnaturalness of tone mapped images based on a subjective study. Experiments show that the modified structural fidelity and statistical naturalness terms in eTMQI better correlate with subjective quality evaluations. Furthermore, we propose an iterative optimization algorithm for tone mapping. The advantages of this algorithm are twofold: 1) eTMQI and TMQI can be compared in a more straightforward way; 2) better quality tone mapped images can be automatically generated by using eTMQI as the optimization goal. Numerical and subjective experiments demonstrate that eTMQI is a superior objective quality assessment metric for tone mapped images and consistently outperforms TMQI.

碩士
國立清華大學
工業工程與工程管理學系
104
With the rapid development of e-commerce applications, online shopping has become more popular and convenient than in-store shopping. E-commerce provides a fast and global platform in which transactions, pre- and post-sales communications take place efficiently and rapidly. Online shopping offers a range of product options with no geographical limitations to customers. Many people choose to use the Internet to search and purchase products and, thus, Internet provides enormous opportunities to consumer goods marketers and manufacturers. In recent years, many e-commerce websites provide consumer feedback functions and social networks, allowing customers to share their purchasing and usage experiences online. Companies collect and analyze information from customers’ reviews through the platform to understand the impressions of customers for products they purchased. Online customer reviews has been widely regarded as an important source of information influencing customers buying decisions. In addition, online customer reviews help companies to redesign their products with key features that better positions to target customers in promising market sectors. This research uses online customer reviews as the business intelligence (BI) corpus. After determining the source webpage of customer reviews, a web crawler needs to collect customer review text. Afterwards, computer-assisted text mining, clustering analysis, association rule mining, and perceptual mapping are applied to develop a formal methodology to compare similar products in a given domain. In this research, the consumer electronic sector is studied. Mobile phone customer reviews are web crawled, collected, mined, and analyzed. The study assists mobile phone manufacturers to understand the voice of customers in both positive and negative perspectives of post-purchasing experiences. The customer-preferred product functions, hardware/software/app features, and price positions, as key business intelligence, are derived for new product designs and market launches.

Knowledge about how body parts are configured is crucial in determining appropriate strategies for achieving desired goals. Prior work suggests that this knowledge is evident in later infancy (Brownell et al., 2010; Slaughter et al., 2004), however, the methods used to assess canonical body knowledge arguably require a conceptual form of knowledge. In contrast, we propose that a functional knowledge about the configuration of the body can be detected in younger infants. We used a tactile localization procedure in which the child's task was to retrieve a target that emitted proprioceptive information via a slight vibration. Children aged 7 - 22 months received targets placed on various locations on the head and body one at a time. The results suggest that even the youngest children in the current study were able to map their actions to get to target locations. Notably, this was also the case for locations that require a form of canonical body knowledge to reach successfully. When the area could be reached with either the ipsilateral or the contralateral hand (i.e., head locations), there was a tendency for ipsilateral hand use, though contralateral hand use increased with increasing age. Visual-proprioception integration (i.e., both seeing and feeling the target on the body) did facilitate manual target localization, however, visual localization became less important for successful manual localization as age increased. In sum, the current study demonstrates the perceptuo-motor competencies that manifest prior to children's ability to succeed on mirror recognition and discrimination tasks.
acase@tulane.edu

In this report, we evaluate the role of visual areas responsive to motion in the human brain in the perception of stimulus speed. We first identified and localized V1, V3A, and V5/MT+ in individual participants on the basis of blood oxygenation level-dependent responses obtained in retinotopic mapping experiments and responses to moving gratings. Repetitive transcranial magnetic stimulation (rTMS) was then used to disrupt the normal functioning of the previously localized visual areas in each participant. During the rTMS application, participants were required to perform delayed discrimination of the speed of drifting or spatial frequency of static gratings. The application of rTMS to areas V5/MT and V3A induced a subjective slowing of visual stimuli and (often) caused increases in speed discrimination thresholds. Deficits in spatial frequency discrimination were not observed for applications of rTMS to V3A or V5/MT+. The induced deficits in speed perception were also specific to the cortical site of TMS delivery. The application of TMS to regions of the cortex adjacent to V5/MT and V3A, as well as to area V1, produced no deficits in speed perception. These results suggest that, in addition to area V5/MT+, V3A plays an important role in a cortical network that underpins the perception of stimulus speed in the human brain.