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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Avaliação da qualidade de ajuste e predição de modelos não lineares: uma aplicação em dados de crescimento de frutos de cacaueiro / Evaluation of the quality of fit and prediction of nonlinear models: an application in growth data of cacao fruits

Eloy, Raquel Aline Oliveira 09 February 2018 (has links)
Atualmente o Brasil é o quinto maior produtor de cacau no mundo e a sua produção está diretamente ligada ao ponto certo da colheita, colher frutos verdes ou verdoengos faz com que suas sementes tenham menor peso, em 1000 frutos maduros as amêndoas secas pesam em média 40 kg, colher frutos verdoengos, ou seja, frutos que estão parcialmente maduros, faz com que esse peso caia para 36 kg em média uma perda verificada de 10%, já quando os frutos estão verdes o peso passa a ser em média de 32 kg, possuindo uma perda de 20%, por isso é importante conhecer as fases de crescimento, que permite estabelecer formas adequadas de manejo, adubação e irrigação. Dentre as características biométricas do fruto do cacaueiro as que tem maior relevância econômica são o comprimento, o diâmetro e o volume. Uma forma de explicar relações de crescimento e produtividade de plantas, árvores, frutos ou animais é por meio da utilização de modelos de crescimento, pois possuem parâmetros com interpretação biológica. Os mais utilizados nestas áreas são os modelos: Logístico, Gompertz, Von Bertalanffy, Richards e Brody, sendo os dois últimos mais utilizados para descrever o crescimento animal. O objetivo do trabalho é avaliar a qualidade de ajuste e de predição dos modelos não lineares, Logístico, Gompertz e Von Bertalanffy, para medidas de comprimento e diâmetro do fruto do cacau, com a finalidade de predizer o seu volume. Para predizer o volume do fruto foi utilizado a fórmula de volume do esferoide prolato. Os critérios AIC e BIC foram utilizados para verificar qual dos modelos se ajusta melhor à essas medidas, já para verificar qual modelo se ajusta melhor na predição do volume do fruto, foram relacionadas as estatísticas: viés médio, índice de concordância, eficiência da modelagem e o desdobramento do quadrado médio do erro de predição. / Currently Brazil is the fifth largest producer of cocoa in the world and its production is directly linked to the right point of harvest, harvesting green or green fruits makes their seeds have less weight, in 1000 mature fruits dry almonds weight on average 40 kg, harvested green fruits, that is, fruits that are partially ripe, causes this weight to fall to 36 kg on average a verified loss of 10%, when the fruits are green the weight becomes an average of 32 kg, with a loss of 20%, so it is important to know the growth phases, which allows to establish appropriate forms of management, fertilization and irrigation. Among the biometric characteristics of the cacao fruit, the most economically important are length, diameter and volume. One way to explain growth and productivity relationships of plants, trees, fruits or animals is through the use of growth models, since they have parameters that with biological interpretation are the most used in these areas: Logistics, Gompertz, Von Bertalanffy, Richards and Brody, the last two being most used to describe animal growth. The objective of this work is to evaluate the quality of fit and prediction of the non linear models, Logistic, Gompertz and Von Bertalanffy, for measures of length and diameter of the fruit of the cocoa, in order to predict its volume. To predict the volume of the fruit, the volume formula of the prolate spheroid was used. The AIC and BIC criteria were used to verify which model best fits these measures, and to verify which model best fits the fruit volume prediction, the statistics were related: mean bias, concordance index, modeling efficiency, and the unfolding of the mean square of the prediction error.
12

Avaliação da qualidade de ajuste e predição de modelos não lineares: uma aplicação em dados de crescimento de frutos de cacaueiro / Evaluation of the quality of fit and prediction of nonlinear models: an application in growth data of cacao fruits

Raquel Aline Oliveira Eloy 09 February 2018 (has links)
Atualmente o Brasil é o quinto maior produtor de cacau no mundo e a sua produção está diretamente ligada ao ponto certo da colheita, colher frutos verdes ou verdoengos faz com que suas sementes tenham menor peso, em 1000 frutos maduros as amêndoas secas pesam em média 40 kg, colher frutos verdoengos, ou seja, frutos que estão parcialmente maduros, faz com que esse peso caia para 36 kg em média uma perda verificada de 10%, já quando os frutos estão verdes o peso passa a ser em média de 32 kg, possuindo uma perda de 20%, por isso é importante conhecer as fases de crescimento, que permite estabelecer formas adequadas de manejo, adubação e irrigação. Dentre as características biométricas do fruto do cacaueiro as que tem maior relevância econômica são o comprimento, o diâmetro e o volume. Uma forma de explicar relações de crescimento e produtividade de plantas, árvores, frutos ou animais é por meio da utilização de modelos de crescimento, pois possuem parâmetros com interpretação biológica. Os mais utilizados nestas áreas são os modelos: Logístico, Gompertz, Von Bertalanffy, Richards e Brody, sendo os dois últimos mais utilizados para descrever o crescimento animal. O objetivo do trabalho é avaliar a qualidade de ajuste e de predição dos modelos não lineares, Logístico, Gompertz e Von Bertalanffy, para medidas de comprimento e diâmetro do fruto do cacau, com a finalidade de predizer o seu volume. Para predizer o volume do fruto foi utilizado a fórmula de volume do esferoide prolato. Os critérios AIC e BIC foram utilizados para verificar qual dos modelos se ajusta melhor à essas medidas, já para verificar qual modelo se ajusta melhor na predição do volume do fruto, foram relacionadas as estatísticas: viés médio, índice de concordância, eficiência da modelagem e o desdobramento do quadrado médio do erro de predição. / Currently Brazil is the fifth largest producer of cocoa in the world and its production is directly linked to the right point of harvest, harvesting green or green fruits makes their seeds have less weight, in 1000 mature fruits dry almonds weight on average 40 kg, harvested green fruits, that is, fruits that are partially ripe, causes this weight to fall to 36 kg on average a verified loss of 10%, when the fruits are green the weight becomes an average of 32 kg, with a loss of 20%, so it is important to know the growth phases, which allows to establish appropriate forms of management, fertilization and irrigation. Among the biometric characteristics of the cacao fruit, the most economically important are length, diameter and volume. One way to explain growth and productivity relationships of plants, trees, fruits or animals is through the use of growth models, since they have parameters that with biological interpretation are the most used in these areas: Logistics, Gompertz, Von Bertalanffy, Richards and Brody, the last two being most used to describe animal growth. The objective of this work is to evaluate the quality of fit and prediction of the non linear models, Logistic, Gompertz and Von Bertalanffy, for measures of length and diameter of the fruit of the cocoa, in order to predict its volume. To predict the volume of the fruit, the volume formula of the prolate spheroid was used. The AIC and BIC criteria were used to verify which model best fits these measures, and to verify which model best fits the fruit volume prediction, the statistics were related: mean bias, concordance index, modeling efficiency, and the unfolding of the mean square of the prediction error.
13

Lyckoparadoxen : Motsättningen mellan lycka, sociala relationer och användandet av sociala medier / The happinessparadox : The contradiction between happiness, social relations and the use of social media

Persson Lidholm, Hillevi, Gullström, Claudia January 2023 (has links)
Sociala relationer är grundläggande för upplevelsen av lycka och sociala medier är utformade för att underlätta dessa. Paradoxalt nog ökar inte användandet av sociala medier alltid upplevelsen av lycka. Syftet med studien har därför varit att undersöka och öka förståelsen för hur kvinnor födda under 70- och 80-talet upplever att deras lycka påverkas av användandet av sociala medier. Sex kvinnor, mellan 35 och 51 år, som använder sociala medier dagligen, rekryterades via sociala medier. Data insamlades via semistrukturerade intervjuer och analyserades genom Interpretative Phenomenological Analysis (IPA). Fyra övergripande teman identifierades - Social tillhörighet, Ändlöst scrollande, Social jämförelse och Medvetet användande. Resultaten visar att deltagarna upplever att ett tydligt syfte med användandet av sociala medier ökar deras lycka, simultant som bristen på medvetet förhållningssätt leder till destruktiva användarbeteenden som minskar lyckan. Samexistensen av positiva och negativa känslor hindrar därmed deltagarna från att känna långvarig och övergripande lycka vid användandet av sociala medier. / Social relationships are fundamental to the experience of happiness and social media is designed to facilitate these. Paradoxically, the use of social media does not always increasethe experience of happiness. The purpose of the study has therefore been to investigate and increase understanding of how women born in the 70s and 80s feel that their happiness is affected by the use of social media. Six women, aged between 35 and 51, who use social media daily, were recruited via social media. Data were collected via semi-structured interviews and analyzed through Interpretative Phenomenological Analysis (IPA). Four overarching themes were identified - Social belonging, Endless scrolling, Social comparison and Conscious use. The results show that the participants feel that a clear purpose for using social media increases their happiness, simultaneously as the lack of a conscious mindset leads to destructive user behaviors that reduce happiness. The coexistence of positive and negative emotions therefore prevents the participants from feeling long-term and overall happiness when using social media.
14

Vilken riktning ska vi ta? : Användarupplevelse av vertikal skrollning i horisontella webbgränssnitt / Which direction should we take? : User Experience of vertical scrolling in horizontal web interfaces

Gerre, Isak, Einarsson, Matilda January 2024 (has links)
Denna studie undersöker användarpreferenser och utmaningar kopplade till horisontella gränssnitt som använder vertikala skrollningsmekanismer på webbplatser. I det snabbt föränderliga digitala landskapet ökar förekomsten av horisontella gränssnitt, särskilt på webbplatser som använder horisontella layouter samtidigt som de behåller traditionella vertikala skrollningsmekanismer. Studien syftar till att analysera användarupplevelser vid sådana gränssnitt med fokus på användarattityder mot vertikal skrollning på horisontellt orienterade webbplatser samt dess inverkan på användbarhet och användarupplevelse.Forskningen innefattade utvecklingen av en prototypwebbplats med ett horisontellt gränssnitt och genomförandet av användartester. Deltagarna interagerade med prototypen genom att använda Tänka Högt-protokoll och System Usability Scale (SUS) vilket gav insikter i deltagarnas uppfattningar och erfarenheter. Resultaten visade blandade attityder mot horisontell skrollning, påverkade av faktorer som mentala modeller, feedbackmekanismer och personliga preferenser. Studien belyser vikten av att anpassa gränssnittsdesignen efter användarförväntningar och feedbackens roll i att förbättra användarupplevelsen. / This study investigates user preferences and challenges associated with horizontal interfaces that use vertical scrolling mechanisms on websites. In the rapidly changing digital landscape, the prevalence of horizontal interfaces is increasing, especially on websites that use horizontal layouts while retaining traditional vertical scrolling mechanisms. The study aims to analyze user experiences with such interfaces, focusing on user attitudes towards vertical scrolling on horizontally oriented websites and its impact on usability and user experience.The research included developing a prototype website with a horizontal interface and conducting user tests. Participants interacted with the prototype using the "Think Aloud" protocol and the System Usability Scale (SUS), providing insights into their perceptions and experiences. The results showed mixed attitudes towards horizontal scrolling, influenced by factors such as mental models, feedback mechanisms, and personal preferences. The study highlights the importance of adapting interface design to user expectations and the role of feedback in enhancing user experience.
15

« Ça dépend » : converser, publier et scroller sur les réseaux sociaux à l’adolescence

Parent, Emmanuelle 11 1900 (has links)
Les adolescentes et adolescents multiplient leurs activités sur Instagram, Snapchat, Tiktok et autres réseaux sociaux. Cette présence en ligne inquiète puisque plusieurs recherches corrèlent l’exposition aux écrans à certains impacts négatifs sur le bien-être. Ces préoccupations vis-à-vis le temps-écran mènent l’État, les entreprises et les organismes communautaires à proposer des recommandations qui visent l’autorégulation. Bien qu’intéressante, cette approche en prévention éclipse les dynamiques collectives mises en lumière par les études en sciences sociales qui rapportent la perspective des ados, suggérant que les réseaux sociaux jouent un rôle important dans le maintien de relations sociales et l’expression personnelle. Cette thèse se penche sur les façons dont les personnes adolescentes participent collectivement et au quotidien à la médiatisation de pratiques sociales dans l’écosystème des plateformes, particulièrement via les réseaux sociaux. Elle rappelle l’importance d’écouter les ados avec leur allégresse, leurs incertitudes et leurs contradictions, afin d’incorporer davantage les questions sociales lorsqu’on parle de leur utilisation des réseaux sociaux, notamment en développant des interventions qui les concernent. L’aspect social de la question de recherche est d’abord observé à travers le concept sensibilisateur de la deep mediatization, rappelant que les pratiques mises en données aujourd’hui sont le berceau des transformations sociales de demain. Avec une attention particulière à l’écosystème des plateformes, les mécanismes de datafication, commodification et sélection ainsi que les affordances permettent de faire un pont entre l’expérience rapportée par les jeunes, la formation de normes sociales, et l’architecture des réseaux sociaux. Mobilisant une méthodologie qualitative, cette démarche donne une voix à des jeunes de 14 à 17 ans de milieux différents, en documentant leur expérience des médias sociaux grâce à une analyse thématique de 19 entrevues et de 2 groupes de discussion. Les résultats de la thèse documentent les façons nuancées dont les personnes adolescentes composent avec leurs relations sociales et la panoplie de fonctionnalités pour converser, publier et scroller. Ces pratiques sociales génèrent des données qui peuvent bénéficier aux réseaux sociaux, et nous invitent à considérer l’ado non pas comme une victime des effets des plateformes, mais comme une personne occupant un rôle actif dans le façonnement de leur écosystème. Cinq normes sont identifiées pour étudier la force injonctive du collectif dans les pratiques des ados: 1) la sensibilité à autrui au moment de converser; 2) la disponibilité en tout temps pour converser; 3) la fréquence et la qualité du contenu partagé selon le type de publication; 4) se présenter authentiquement conforme et 5) scroller sur les réseaux sociaux les plus populaires. Enfin, on apprend que les ados considèrent davantage les relations sociales que les fonctionnalités lorsqu’une pratique est collectivement imbriquée, comme l’entretien d’une conversation médiatisée ou la publication. Et à l’opposé, les ados se disent plus affecté.e.s par les fonctionnalités du réseau social quand l’activité est réalisée individuellement, comme scroller. Comprendre l’agentivité de l’environnement en ligne et son processus normatif selon le caractère social d’une pratique nous informe de nouvelles manières d’intervenir auprès des ados pour une utilisation plus lucide du numérique. / Adolescents are using Instagram, Snapchat, Tiktok and other social media more than ever before. Their increased presence online is worrisome because a number of studies establish correlations between screen time and negative impacts on well-being. Concerns about the amount of time spent with screens have led governments, companies and community organizations to issue recommendations that call for self-regulation of time spent online. Despite its benefits, this approach to prevention fails to consider the collective dynamics highlighted by social science research that, drawing on adolescents’ perspectives, illustrate the important role of social media in personal expression and maintaining social relationships. This thesis examines the ways in which adolescents participate collectively and on a daily basis in the mediatization of social practices within an ecosystem of platforms, particularly through their activities on social media. It argues for the importance of listening to adolescents’ voices, with all their enthusiasm, uncertainties, and contradictions, in order to look beyond individual uses of social media when designing programs and interventions that concern them. We frame our observations using the sensitizing concept of deep mediatization, that reminds us how today’s data practices are the source of tomorrow’s societal transformations. Within an ecosystemic perspective on digital platforms, the concept of affordances establishes links between the mechanisms of datafication, commodification and selection, platform architectures, the formation of social norms and youth’s experiences on social media. Using a qualitative methodology, we documented the social media experiences of young people aged 14 to 17 from a variety of backgrounds, through a thematic analysis of 19 interviews and two focus groups. The results document the subtle ways that adolescents manage their social relationships and the multiple functionalities offered by these media to converse online, post content and scroll. While direct messaging, posting and scrolling all generate data that fuel the economic model of various social media platforms, the active role of young people on social media invites us to consider adolescents not as victims needing protection from social media but as fullfledged participants in shaping their ecosystem. The injunctive effect of the community on adolescents’ practices is apparent in five norms identified from their comments : 1) being sensitive to others while direct messaging; 2) the expectation of constant availability to converse online; 3) implicit rules about the frequency and quality of content posted according to the type of publication; 4) presenting oneself authentically while fitting in (i.e. being a unique individual but not too different); and 5) scrolling on the most popular social media. Our results demonstrate that when a practice is collectively configured and visible, as in the case direct messaging or posting, adolescents rely heavily on social cues and relationships and platform functionalities have limited effects. In contrast, they appear to be more dependent on what the platforms propose when an activity, like scrolling, is primarily individual. Understanding how the agency of the online environment and the normative processes at work vary according to the social characteristics of different social media practices opens the door to imagining new ways of intervening in order to encourage a more lucid use of digital environments by youth.
16

DRAWN TO LIFE: Exploring real-time manipulation of the digitally represented surface in comics on smartphones and tablets

Ericsson Duffy, Mikael January 2013 (has links)
This research thesis is an exploration into what possibilities lie beyond the representation of analog material when it transcends into the digital realm. Specifically, how printed comics can be altered in realtime by creator- allowed user interaction, when adapted for presentation within the digital sphere of mobile smartphones and computer tablets. Using legacy computer-game techniques like parallax scrolling with modern digital layer filters, device sensors and applying them in realtime to the comic creators digitally layered content, alternative forms of presentation arise.This is an investigation into the comic creator’s will of allowing possibilities of added depth perception, interactivity and alternative visual narratives in their comic, manga or graphic novels when employing new techniques based on sensor data input from a reader, like accelerometer-, gyroscope- or eye-tracking sensors. Several different techniques are evaluated. The focus is mainly on the context of creators of comics or manga who use digital tools and layer compositions when producing their work. Several aspects of the user-centered experience are also explored.Although mainly an interaction design project, most of the design methods are used from a service design approach, emphasizing co-design techniques like interviews, observations and user tests. The results are digital prototypes and proof-of-concepts featuring technology tests that support final design conclusions.The results will show both enthusiasm and reluctance from test subjects towards the new technologies presented. The professional craft of comic, manga and graphic novel creation has a deeply rooted aesthetic and production cycle in its history of the printed form. It could be difficult to alter its standard, reverence and nostalgia in the eyes of its readers and creators, when pursuing the digital format and narrative possibilities of the future. A video explaining the project’s “Drawn To Life” technology is available online.
17

Le noir comme invention du cinéma : matière, forme, dispositif / Black as Cinema's Invention : material, form, device

Kuo, Li-Chen 21 November 2018 (has links)
Antipode de la lumière, le noir est pourtant indissociable du cinéma. Qu'est-ce que le noir du cinéma ? Figure de l'ombre ou de l'obscurité à l'image, il y est aussi présent en tant que tel, un noir sans représentation et avec sa réalité physique singulière. Ce noir-là est avant tout une condition technique, que l'on cache, mais qui joue un rôle décisif dans la production des illusions d'optique et la création de la fiction. Il est également omniprésent dans tout le processus de fabrication de l'image cinématographique. Le noir joue avec la lumière, conditionne la visibilité et l'invisibilité et, en ce sens, invente le cinéma. Le noir propose une autre manière de comprendre ce qu'est le cinéma ainsi que son fonctionnement. Cette étude traitera d'abord l'aspect matériel de l'image argentique : le noircissement photochimique et les idées qu'il suggère en tant que processus de la formation et de la dissolution de l'image. On évoquera ensuite, au travers du noir formel, outil rhétorique et mécanique, les effets produits par le noir, lorsqu'il intervient en tant que forme dans l'image, de l'image, et entre les images. Enfin, en tant que dispositif envahisseur de l'écran et de l'espace de projection, le noir révèlera son rôle dans le dispositif du spectacle visuel : la construction d'un accès à l'illusion et à la révélation. Chaque partie se déploiera dans un parcours à la fois historique, technique, et esthétique. On verra notamment dans des tentatives artistiques et expérimentales que la mise en avant du noir permet de révéler les caractéristiques du médium cinématographique, voire de ré-inventer le cinéma. Cette quête du noir se révèle comme une quête sur la nature du cinéma, nature que l'industrie du cinéma tente d'effacer. Le noir fait voir, et il fait voir autrement. / Even though black is the antipode of light it is nevertheless inseparable from the world of cinema. What is black in cinema? A figure of shadow or darkness in the image that is also present as such. Black without representation and with its singular physical reality. This blackness is above all a technical condition which is hidden but which plays a decisive role in the production of optical illusions and the creation of fiction. It is also omnipresent in the entire process of making the cinematographic image. Black plays with light and conditions visibility and invisibility. In this sense it invents cinema. Black also offers another way of understanding what cinema is and how it works. This study will first deal with the material aspect of photography: photochemical blackening and the ideas it suggests as a process of image formation and dissolution. I will then portray the different effects produced by black- the black shape a rhetorical and mechanical tool. When it intervenes as a form in the image, of the image, and between the image. Finally, I will discuss how black can be an invading device of the screen and the projection space and reveal its role as a visual spectacle apparatus: the construction of an access to illusion and revelation. Each part of this outline will be dealt with in a historical, technical and aesthetic way. We will see in particular in artistic and experimental attempts that the emphasis on black makes it possible to reveal the characteristics of the cinematographic medium or even to re-invent cinema. This quest for blackness is revealed as a quest for the nature of cinema. A nature that the film industry is trying to erase. Black makes you see but it makes you see differently.

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