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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.
81

Multi-objective hyper-heuristics and their application to water distribution network design

McClymont, Kent January 2012 (has links)
Hyper-heuristics is a new field of optimisation which has recently emerged and is receiving growing exposure in the research community and literature. Hyper-heuristics are optimisation methods which are designed with a high level of abstraction from any one specific problem or class of problems and therefore are more generally applicable than specialised meta-heuristic and heuristic methods. Instead of being designed to solve a specific real-world problem, hyper-heuristics are designed to solve the problem of heuristic generation and selection. As such, hyper-heuristics can be thought of as methods for optimising the operations of an optimisation process which finds good solutions to a problem as a by-product. This approach has been shown to be very effective and in some cases provides improvement in search performance as well as reducing the burden associated with tailoring meta-heuristics which is often required when solving new problems. In this thesis, the hypothesis that hyper-heuristics can be competitively applied to real-world multi-objective optimisation problems such as the water distribution design problem is tested. Although many single-objective hyper-heuristics have been proposed in the literature, only a few multi-objective methods have been proposed. This thesis explores two different novel multi-objective hyper-heuristics: one designed for generating new specialised heuristics; and one designed for solving the online selection of heuristics. Firstly, the behaviour of a set of heuristics is explored to create a base understanding of different heuristic behavioural traits in order to better understand the hyper-heuristic behaviours and dynamics later in the study. Both approaches are tested on a range of benchmark optimisation problems and finally applied to real-world instances of the water distribution network design problem where the selective hyper-heuristics is demonstrated as being very effective at solving this difficult problem. Furthermore, the thesis demonstrates how heuristic selection can be improved by incorporating a greater level of information about heuristic performance, namely the historical joint performance of different heuristics, and shows that exploiting this sequencing information in heuristic selection can produce highly competitive results.
82

”Man vill ju få lite wow-effekt” : En fokusgruppsstudie om identitet på Instagram / One wants to get a wow - effect : A focus group study of identity on Instagram

Hakami, Natasha, Lindell, Cecilia January 2016 (has links)
This thesis examines Instagram users and how they create an identity, and their interaction with other users. The aim of this study is to understand what we do with Instagram and what Instagram does with us in our everyday lives, and what the effects of the medium entails. This thesis is based on theories of identity, hyper- reality and effects of the development of social media. The method used in this study is qualitative focus group interviews with five women and five men, where the answers are transcribed and analyzed to gain an understanding of the effects and the impact of Instagram in their lives. We chose to interview both men and women, and therefore we have also had the gender issue in mind, but it has not been the main focus of this study. The results we reached in this study is that Instagram is mainly used to keep updated and that the medium provides both positive and negative effects. We also discovered that individuals are not one hundred percent themselves on Instagram. The conclusion we can draw is that people play different roles on Instagram of different purposes, and that we live in a hyper- reality that brings both good and bad. We can also conclude that even though people today have the power to present themselves in the way they want to, we see tendencies that gender representation is present in a stereotypical way.
83

Characterization and Mitigation of Hyper-Rayleigh Fading

Ketcham, Richard 30 November 2007 (has links)
Due to the unprecedented spatial and temporal resolution they offer, wireless sensor networks are considered an enabling technology for the distributed monitoring of industrial, military, and natural environments. As these systems migrate into vastly different and novel applications, new constraints are discovered that affect network reliability and utility. For example, wireless sensors are typically statically deployed and, unlike mobile systems, cannot move to a new location for better radio reception. As a result, the signal fades caused by non-optimal environmental conditions can increase the outage probability of the system, potentially rendering the network unreliable and ineffectual. Stochastic models that quantify link reliability and the effectiveness of diversity methods are often employed to understand the impact of such fading. However, the performance of these models applied to wireless sensor networks is entirely dependent on the appropriateness of the model with respect to the environment. This work first presents an empirical study of the propagation environment for a wingless, rotary aircraft, showing that the wireless environment within exhibits frequency-selective fading much more severe than predicted by current worst-case models (i.e., Rayleigh). An analysis is then given of the effectiveness of several diversity methods operating within such environments (referred to as hyper-Rayleigh). These fade mitigation techniques are simple enough to be employed for use with low-complexity wireless sensor hardware, and include spatial diversity, polar diversity, two-element passive combining, and two-element phased combining. Two-element phased combining is further developed by examining the effect that smaller element spacing has on diversity gain. A demonstration of a wireless
84

Lung Impedance Measurements Using Tracked Breathing

Nirav, Daphtary 16 June 2010 (has links)
The forced Oscillation Technique (FOT) can be used to measure lung impedance continuously during breathing. However, spectral overlap between the breathing waveform and the applied flow oscillation can be problematic if the frequency content of spontaneous breathing is unknown. This problem motivated us to develop a modification to the FOT system called the Tracked Breathing Trainer. The modification uses biofeedback to constrain subjects to breathe at a single predetermined frequency. This thesis investigates the engineering and physiological aspects of the modification we made. We studied 8 adult non-asthmatic and 8 adult asthmatic subjects. Three 16 s perturbatory flow oscillation signals ranging from 1-40 Hz were used on the subjects. Each subject received three trials per perturbation for both spontaneous and tracked breathing. We then fitted a resistance-elastance-inertance model of the lung to each data set. For non-asthmatic subjects, the average resistance (R) and elastance (E) values for the first spontaneous breathing trial were 2.5±0.15 cmH2O.s.ml-1 and 18.1±3.55 cmH2O.ml-1, and for the third spontaneous breathing trial were 2.4±0.12 cmH2O.s.ml-1 and 21.8±4 cmH2O.ml-1. R and E for the first tracked breathing trial were 2.3±0.21 cmH2O.s.ml-1 and 33.6±7.4 cmH2O.ml-1, and for the third tracked breathing trial were 2.4±0.14 cmH2O.s.ml-1 and 25.75±4.3 cmH2O.ml-1, respectively. For asthmatic subjects, the average R and E values for the first spontaneous breathing trial were 3.32±0.68 cmH2O.s.ml-1 and 39.13±9.8 cmH2O.ml-1, and for the third spontaneous breathing trial were 3.12±0.15 cmH2O.s.ml-1 and 39.91±6.2 cmH2O.ml-1. R and E for the first tracked breathing trial were 2.86±0.15 cmH2O.s.ml-1 and 32.47±4.1 cmH2O.ml-1, and for the third tracked breathing trial were 2.86±0.21 cmH2O.s.ml-1 and 33.89±10 cmH2O.ml-1, respectively. These results show that R was consistently lower during tracked breathing than spontaneous breathing in both non-asthmatic and asthmatic subjects. However, an increase in E was observed during tracked breathing. We suspect this effect may have resulted from dynamic hyperinflation. These results also show that R and E are reproducible with both spontaneous and tracked breathing, and that R and E were not noticeably different between both breathing maneuvers. We conclude that using biofeedback to control the breathing pattern during application of the FOT in normal subjects does not significantly affect impedance measurements, and thus may be useful for avoiding spectral overlap between FOT perturbations and the breathing pattern.
85

The shopping channel : simulation, consumption, and the author as cultural critic in Don DeLillo's White Noise

Lacerte, Pierre January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
86

Towards modeling of a class of bionic manipulator robots / Vers la modélisation d’une classe de robots mobiles manipulateurs bioniques

Escande, Coralie 12 December 2013 (has links)
Ce travail concerne une catégorie de robot mobile manipulateur omnidirectionnel bionique, en l’occurence le RobotinoXT qui dispose d’un manipulateur bionique CBHA monté sur un robot mobile omnidirectionnel, nommée Robotino. D’abord, nous avons proposé un modèle cinématique direct de ce système en utilisant une méthode nommée « arc geometry ». Celle-ci a été validée grâce à un banc d’expérimentation en ayant recours à une technique de trilatération. Pour atteindre cet objectif, les capteurs ont été calibrés. Concernant le problème de calibration des paramètres constants du modèle, il a été résolu en développant un algorithme d’optimisation incluant une méthode nommée SQP, validée via un manipulateur industriel à bras rigides. Puis, nous avons proposé un modèle cinématique inverse du CBHA en supposant que chaque vertèbre de celui-ci est assimilée à un robot parallèle. Ce modèle a été validé par les mesures réelles obtenues avec le manipulateur industriel, permettant la définition de l’espace de travail du robot. Enfin, nous avons implémenté une boîte à outils qui englobe les modèles développés dans ce travail. / This work deals with a particular class of mobile omnidrive-bionic manipulator robot namely RobotinoXT. It contains a bionic manipulator Compact Bionic Handling Assistant (CBHA) mounted over a mobile omnidrive robot Robotino. We first proposed a forward kinematic model of such a system by using an “arc geometry” method which was validated through a test bench using a trilateration technique. To achieve this purpose, the sensors were calibrated. For the model’s constant parameters calibration problem, this latter was resolved by developing an optimization algorithm which incorporates a SQP method, validated via an industrial manipulator with rigid links. Then, we proposed an inverse kinematic model of the CBHA by assuming that each backbone of it, is assimilated to a parallel robot. This model was validated by real measurements obtained with the industrial manipulator, allowing defining the robot workspace. Finally, we implemented a toolbox which encompasses the models developed in this work.
87

Impact of in-store actions on brand relationship quality : Application to fast moving consumer goods distributed in hyper and supermarkets / Impact des actions au point de vente sur la qualité de la relation consommateur-marque : Le cas des produits de grande consommation distribués en grandes et moyennes surfaces

Mussol, Sarah 13 November 2014 (has links)
Comment les relations consommateurs-marques peuvent-elles être développées en magasin ? Beaucoup de recherches sur les actions au point de vente les ont étudiées dans une perspective transactionnelle tandis que le marketing relationnel a prêté peu d'attention à ce qui se passe en magasin. Cependant le point de vente constitue un point de contact essentiel entre consommateurs et marques. Sur la base de deux études qualitatives et d'une étude expérimentale, cette recherche se concentre sur l'impact des actions en magasin sur les relations consommateurs-marques. Nous différencions les actions relationnelles des actions transactionnelles pour comparer leurs effets. L'application empirique est faite avec des marques de glaces distribuées en grandes et moyennes surfaces. Un questionnaire en ligne est mis en place pour tester des actions fictives que les marques pourraient mettre en œuvre. Nos résultats montrent l'intérêt pour les marques d'utiliser des actions relationnelles au point de vente. Les personnes exposées à des actions relationnelles attribuent plus souvent l'action à la marque. Ils perçoivent des efforts et une orientation relationnelle de la marque plus importants, ils s'identifient plus avec la marque, et déclarent ainsi une plus grande fidélité envers celle-ci. L'originalité de la recherche réside dans la prise en compte des actions en magasin dans une perspective relationnelle. Plus généralement, la conceptualisation et l'étude de l'impact de ce genre d'actions mettent en évidence une façon plus sociale de tenir compte des interactions entre les consommateurs et les marques. / How can be developed and impacted relationships in store ? Many researches have studied in-store actions in a transactional perspective while relationship marketing has paid little attention to what happens in store. However, stores constitute a key point of contact between consumers and brands. Based on two qualitative studies and an experimental study, this research focuses on the impact of in-store actions on consumer-brand relationships. It differentiates relational and transactional actions and compares their effects. The empirical application involves ice cream brands distributed in the super-hypermarket channel. An online questionnaire is implemented to test fictitious actions that brands could implement. Our results show the interest for manufacturers brands to use relational in-store actions. Individuals exposed to relational in-store actions attribute more frequently the effort to the manufacturer. They perceive stronger efforts and brand expression, they identify more with the brand, and declare a higher loyalty to the latter. The originality of the research lies in the consideration of in-store actions in a relational perspective. More generally, the conceptualization and the study of the impact of these kinds of actions highlight a more social way to consider interactions between consumers and brands in the marketplace.
88

Aproximación y análisis semiótico del consumo e hiperconsumo en el discurso publicitario / Approximation and semiotic analysis of consumption and hyperconsumption in advertising discourse

Yalán Dongo, Eduardo Enrique 24 April 2019 (has links)
La presente es una investigación y aplicación metodológica que tiene como objetivo general el estudio del discurso publicitario peruano contemporáneo asociado a relaciones sociales de la sociedad de consumo. El tema se encargará de mostrar, exponer y estudiar las diferencias discursivas y narrativas entre los nuevos modos de producción publicitaria (propios del hiperconsumismo) y los modos “tradicionales” publicitarios (propios de la sociedad de consumo) mediante el estudio semiótico de las campañas de Inca Kola (motor y motivo) & BCP (decisiones de la vida) en el Perú del año 2011 como representantes de tales discursos. La investigación considera el estudio de las relaciones discontinuas del consumo como principal factor que determina la significación de la publicidad. Partiendo de esta primera noción y adoptando la tesis de una figura ternaria de la sociedad de consumo (la fase 1 (1880-1945), la fase 2 (1950-1985) y la fase 3 (1985 - ¿?)), es que se relacionará por tanto a la fase 1 y 2 con la llamada “publicidad tradicional” y la fase 3 con la “publicidad no tradicional” o hiperpublicidad. Estos tres tipos de discurso no se eliminan, sino que conviven y funcionan en la comunicación contemporánea adecuándose a los códigos sociales logrando modular su sentido. La investigación sustenta, partiendo de esta discontinuidad o cambio en las prácticas de consumo, que se han suscitado modificaciones en la comunicación publicitaria actual ocasionando que la narrativa y discurso de la publicidad tradicional produzca lecturas y sentidos contrarios o tangenciales respecto a dicha comunicación publicitaria. / This is a research and methodological application that has as a general objective the study of contemporary Peruvian advertising discourse associated with social relations of the consumer society. The theme will be responsible for showing, exposing and studying the discursive and narrative differences between the new modes of advertising production (typical of hyper-consumerism) and the "traditional" advertising modes (typical of the consumer society) through the semiotic study of advertising campaigns Inca Kola (motor and motive) & BCP (life decisions) in Peru in 2011 as representatives of such speeches. The investigation considers the study of the discontinuous relations of consumption as the main factor that determines the significance of advertising. Starting from this first notion and adopting the thesis of a ternary figure of the consumer society, namely phase 1 (1880-1945), phase 2 (1950-1985) and phase 3 (1985 -?). Is which will therefore relate to phase 1 and 2 with the so-called "traditional advertising" and phase 3 with "non-traditional advertising" or hyper-advertising. These three types of discourse are not eliminated, but they coexist and function in contemporary communication, adapting to the codes and social foundations and modulating their meaning. The research is based on this discontinuity or change in consumer practices that have led to changes in the current advertising communication causing the narrative and discourse of traditional advertising to produce readings and contrary or tangential views regarding such advertising communication. / Tesis
89

Modeling, measurement and performance of World Wide Web transactions

Barford, Paul R. January 2001 (has links)
Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / The size, diversity and continued growth of the World Wide Web combine to make its understanding difficult even at the most basic levels. The focus of our work is in developing novel methods for measuring and analyzing the Web which lead to a deeper understanding of its performance. We describe a methodology and a distributed infrastructure for taking measurements in both the network and end-hosts. The first unique characteristic of the infrastructure is our ability to generate requests at our Web server which closely imitate actual users. This ability is based on detailed analysis of Web client behavior and the creation of the Scalable URL Request Generator (SURGE) tool. SURGE provides us with the flexibility to test different aspects of Web performance. We demonstrate this flexibility in an evaluation of the 1.0 and 1.1 versions of the Hyper Text Transfer Protocol. The second unique aspect of our approach is that we analyze the details of Web transactions by applying critical path analysis (CPA). CPA enables us to precisely decompose latency in Web transactions into propagation delay, network variation, server delay, client delay and packet loss delays. We present analysis of pe1formance data collected in our infrastructure. Our results show that our methods can expose surprising behavior in Web servers, and can yield considerable insight into the causes of delay variability in Web transactions. / 2031-01-01
90

Caracterização e avaliação dos usuários frequentes (hiperutilizadores) do serviço público de urgência/emergência do município de Monte Alto/SP / Description and appraisal of frequent users (hyper users) of public immediacy/emergency needs of service in Monte Alto county/SP

Melo, Sueli Regina Alves de 15 March 2019 (has links)
O objetivo do presente estudo foi rever na literatura qual a definição de usuários frequentes/hiperutilizadores de serviços de urgência e emergência e conhecer as implicações destes usuários no serviço de urgência e emergência. Trata-se de um estudo realizado através Scoping Review, conforme a proposta do Joanna Briggs Institute (JBI). Resultados: Identificados 37 estudos e através da leitura do título e resumo, selecionados 27 para leitura na íntegra. Porém após a leitura detalhada foram excluídos 11 estudos que não apresentavam resultados e conclusões diretamente ligados à temática. Assim, a amostra final foi composta por 16 estudos. Entre estes, quatro eram brasileiros e escritos pelo mesmo autor. Não houve 18 consenso entre s autores quanto a definição do termo pesquisado, todavia indicaram como usuário frequente/hiperutilizador o paciente que utiliza o serviço de urgência e emergência mais de 3 vezes por ano. Conclusões: Há lacuna na literatura e não consenso sobre a temática. Há necessidade de mais estudos sobre o assunto para o delineamento de ações que possibilitem a melhora deste quadro / The purpose of this study is to review the definition done by the literature of frequent / hyper-users of immediacy and emergency services and to know the involvement of such users in the immediacy and emergency services. This is a study conducted through Scoping Review (Revisão de Alcance) as proposed by Joanna Briggs Institute (JBI). Results: 37 studies were identified and by means of reading the titles and abstracts, 27 were selected as for thorough reading. However after the itemized reading, 11 studies that did not bring forward results and conclusions directly related to the thematic, they were excluded. So the final specimen was consisted of 16 studies. Four amongst these were Brazilian and written by the same author. There was no consensus between the authors regarding definition of the searched word, nevertheless they indicated as frequent / hyper-user the patient who uses the immediacy and emergency services more than thrice a year. Conclusions: There is a vacuity in literature and no agreement on this thematic. There are needs for further studies on the topic for the delineation of actions to make improvements possible for this picture

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