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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.
491

Development of a soft-core based power electronic conversion controller

Nsumbu, Cassandra Daviane January 2014 (has links)
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2014. / The application of digital control techniques has become dominant in power electronics owing to several advantages they present, when compared to analogue solutions. Their development is based on the use of microprocessors and microcontrollers, such as Application Specific Integrated Circuit (ASIC), Digital signal processors (DSP), Field Programmable Gate Arrays (FPGA), or a combination of these devices. This thesis presents an investigation of a soft-core based FPGA control system as a solution for power electronic applications. The aim was the development and implementation of a conversion controller, which purpose is to supply control inputs in the form of digital Pulse Width Modulation (PWM) signals, to a number of power electronic applications, such as single half and full bridge DC-DC converters, three phase and multicell inverters. The PWM control technique is achieved via their power semiconductor switching devices. These PWM control signals are necessary for the high frequency conversion of an analog input voltage (AC, DC or unregulated) to an analog output voltage of another level (AC or DC). This was intended to be achieved by exploiting and combining the advantages that FPGA and embedded processors provide such as high reconfigurability and multipurpose ability. This controller’s digital outputs, namely PWM switching signals, can be directly delivered to an analog signal amplification circuit to create an adequate voltage level before being processed by the converters’ switches.
492

Aplicação de redes neurais artificiais na análise de dados de molhamento foliar por orvalho /

Mathias, Ivo Mário, 1959- January 2006 (has links)
Resumo: O trabalho descrito nesta tese apresenta o desenvolvimento de um sistema computacional denominado PMNeural, baseado em Redes Neurais Artificiais (RNAs). A finalidade do sistema é o tratamento de dados climáticos e de molhamento foliar por orvalho, visando reconhecer padrões de comportamento de variáveis meteorológicas em relação ao molhamento foliar por orvalho. Para determinar as melhores arquiteturas e algoritmos de treinamento de RNAs, bem como, definir quais as variáveis climáticas que influenciam significativamente na ocorrência do molhamento foliar, foram utilizados dois simuladores: o simulador SNNS (Stuttgart Neural Network Simulator) versão 4.2, que utiliza plataforma operacional Linux e o simulador JavaNNS - Java Neural Network Simulator 1.1, com ambiente de execução Windows, o qual é baseado no SNNS. Foram utilizados dados climáticos de três estudos de caso, dois destes referentes à cultura do trigo, oriundos de locais e datas diferentes. Base de Dados 1 - Fazenda Capão do Cipó, em Castro - PR, safra de inverno de 2003. Base de Dados 2 - Campo Demonstrativo e Experimental da Fundação ABC - Fazenda Palmeirinha, em Piraí do Sul - PR., safra de inverno de 2005. Base de Dados 3 - Posto Agrometeorológico ESALQ/USP em Piracicaba - SP, período entre julho e setembro de 2005. Um quarto estudo de caso foi elaborado a partir dos arquivos dos estudos de casos 1, 2 e 3, utilizando-se as variáveis climáticas comuns, juntamente com seus respectivos índices de molhamento. Dentre os algoritmos de treinamento testados nos simuladores, o Resilient 2 Propagation (Rprop) foi o que apresentou as menores taxas de erro em relação aos outros... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The work described in this thesis presents the development of a computational system named PMNeural based on Artificial Neural Networks (ANNs). The system has for purpose the handle of climatic and leaf wetness data, aiming to recognize patterns of behavior of meteorological variables in relation to the wetness from dew. Two simulators were used in order to determine the best architecture and ANNs training algorithms, as well as, to define which the climatic variables that influence significantly in the leaf wetness occurrence: the SNNS (Stuttgart Neural Network Simulator) version 4.2 for Linux platform, and the JavaNNS - Java Neural Network Simulator 1.1, for Windows platform, which is based on the SNNS. Climatic data of three case studies were used, two related to wheat culture, obtained from different places and dates. Dataset 1 - Capão do Cipó Farm, in Castro - PR, 2003. Dataset 2 - Palmeirinha Farm in Piraí do Sul - PR, 2005 winter crop. Dataset 3 - Meteorological Station of ESALQ/USP in Piracicaba - SP, from July to September, 2005. A fourth case study was elaborated from datasets of the case studies 1, 2 and 3, using the common climatic variables together with their respective wetness indexes. After testing the training algorithms in the simulators, the Resilient Propagation (Rprop) presented lower training errors than the others evaluated methods: Backpropagation Standard, Backpropagation for batch training, Backpropagation with momentum term, Backpropagation with chunkwise update, Backpropagation with Weight Decay and Quickprop. It was verified 4 also that, among the climatic variables used for classification of leaf wetness from dew, the inclusion of the schedule had influenced in the obtaining better ANNs results... (Complete abstract, click electronic access below) / Orientador: Angelo Cataneo / Coorientador: Alaine Margarete Guimarães / Banca: Célia Regina Lopes Zimback / Banca: Marco Antonio Martim Biaggioni / Banca: Manoel Henrique Salgado / Banca: Marcelo Giovanetti Canteri / Doutor
493

Intuições para uma pedagogia da intuição : a amizade enquanto uma experiência integral pela dinâmica das cartas

Machado, Alexsandro dos Santos January 2012 (has links)
A partir de uma de uma atividade denominada “Dinâmica das Cartas”, o autor convidou seus estudantes do Ensino Médio a escreverem cartas para si mesmos a serem recebidas cinco anos depois. Após esse período, conforme o combinado, tais cartas foram remetidas de volta aos seus autores pelo correio e houve um reencontro com todos os participantes. Trinta e oito voluntários aceitaram o convite do autor e continuaram um processo de aprofundamento de reflexões sobre a Dinâmica das Cartas por meio de e-mails, cartas e encontros presenciais. O produto desse processo foi analisado pelo autor a partir da obra de Henri Bergson, de maneira especial, por meio dos conceitos de intuição, memória, duração e experiência integral. Constatou-se que, sustentada pela amizade, as experiências escolares podem envolver a inteligência e a intuição, mediante um misto de processos da mente e da memória, que podem se entrelaçar em experiências integrais. Por fim, ao verificarmos que a intuição é o fio metodológico capaz de, em complemento à inteligência, transformar as vivências educativas em experiências integrais, apontamos a necessidade de se organizar pressupostos mais consistentes para uma Pedagogia da Intuição. / From an activity called a "Dynamics of Letters", the author invited his high school students to write letters to themselves to be received five years later. After this period, as agreed, such letters were sent back to their authors by mail and there was a meeting with all participants. Thirty-eight volunteers accepted the invitation of the author and continued a process of deepening reflection on the dynamics of letters through e-mails, letters and meetings. The product of this process was analyzed by the author based on work of Henri Bergson, especially, through the concepts of intuition, memory, duration and integral experience. Thus, we conclude that through friendship, the dynamics of the Letters was formed as an integral experience. We see through this dynamic that the school experiences may involve intelligence and intuition, through a combination of processes of the mind and memory, which can be interwoven through the integral experiences. Finally, to verify that intuition is the thread methodological able to, in addition to intelligence, transform the educational experiences in integral experiences, highlighting the need to organize more consistent fundamentals for a Pedagogy of Intuition.
494

Intuições para uma pedagogia da intuição : a amizade enquanto uma experiência integral pela dinâmica das cartas

Machado, Alexsandro dos Santos January 2012 (has links)
A partir de uma de uma atividade denominada “Dinâmica das Cartas”, o autor convidou seus estudantes do Ensino Médio a escreverem cartas para si mesmos a serem recebidas cinco anos depois. Após esse período, conforme o combinado, tais cartas foram remetidas de volta aos seus autores pelo correio e houve um reencontro com todos os participantes. Trinta e oito voluntários aceitaram o convite do autor e continuaram um processo de aprofundamento de reflexões sobre a Dinâmica das Cartas por meio de e-mails, cartas e encontros presenciais. O produto desse processo foi analisado pelo autor a partir da obra de Henri Bergson, de maneira especial, por meio dos conceitos de intuição, memória, duração e experiência integral. Constatou-se que, sustentada pela amizade, as experiências escolares podem envolver a inteligência e a intuição, mediante um misto de processos da mente e da memória, que podem se entrelaçar em experiências integrais. Por fim, ao verificarmos que a intuição é o fio metodológico capaz de, em complemento à inteligência, transformar as vivências educativas em experiências integrais, apontamos a necessidade de se organizar pressupostos mais consistentes para uma Pedagogia da Intuição. / From an activity called a "Dynamics of Letters", the author invited his high school students to write letters to themselves to be received five years later. After this period, as agreed, such letters were sent back to their authors by mail and there was a meeting with all participants. Thirty-eight volunteers accepted the invitation of the author and continued a process of deepening reflection on the dynamics of letters through e-mails, letters and meetings. The product of this process was analyzed by the author based on work of Henri Bergson, especially, through the concepts of intuition, memory, duration and integral experience. Thus, we conclude that through friendship, the dynamics of the Letters was formed as an integral experience. We see through this dynamic that the school experiences may involve intelligence and intuition, through a combination of processes of the mind and memory, which can be interwoven through the integral experiences. Finally, to verify that intuition is the thread methodological able to, in addition to intelligence, transform the educational experiences in integral experiences, highlighting the need to organize more consistent fundamentals for a Pedagogy of Intuition.
495

Influência do turno de trabalho noturno sobre a pressão arterial e prevalência de hipertensão em equipe de enfermagem de hospital de grande porte

Sfredo, Carla Cristina Farias January 2009 (has links)
Objective: To evaluate the association between shift work and blood pressure, pre-hypertension and hypertension in nursing personnel of a large general hospital. Methods: In a cross-sectional survey, 493 nurses, nurse technicians and assistants, were selected at random in a large general hospital. Hypertension was diagnosed by the mean of four automatic blood pressure readings>= 140/90 mmHg or use of blood pressure lowering agents, and pre-hypertension by systolic blood pressure>= 120-139 or diastolic blood pressure>= 80-89 mmHg. Risk factors for hypertension were evaluated by a standardized questionnaire and anthropometric measurements. The association between turns of work, defined as day or night, and by the combination of turns, and blood pressure, pre-hypertension and hypertension was explored in bivariate and multivariate analyses, controlling for risk factors for hypertension by covariance analysis and modified regression Poisson. Results: The mean age of the participants was 34.3 ± 9.4 years and 88.2% were women. Night shift workers were older, more frequently married or divorced, and less educated. The prevalence of hypertension in the whole sample was 16%, and 28% had pre-hypertension. Blood pressure (after adjustment for confounding) was not different in day and night shift workers. The prevalence of hypertension and pre-hypertension by shift work (day/night and combination of turns) was not different in the bivariate analysis and after adjustment for confounding (all risk ratios = 1.0). Conclusion: Night shift work is not associated with blood pressure, hypertension and pre-hypertension in nurses and nurses assistants working in a large general hospital.
496

Comportamento e fisiologia reprodutiva do macho de Podisus nigrispinus (Dallas) (Hemiptera : Pentatomidae) / Male reproductive behavior and physiology of Podisus nigrispinus (Dallas) (Hemiptera : Pentatomidae)

RODRIGUES, Agna Rita dos Santos 01 February 2008 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-11-22T15:55:38Z No. of bitstreams: 1 Agna Rita dos Santos Rodrigues.pdf: 1041996 bytes, checksum: 09225af0315071627118074737e4ebda (MD5) / Made available in DSpace on 2016-11-22T15:55:38Z (GMT). No. of bitstreams: 1 Agna Rita dos Santos Rodrigues.pdf: 1041996 bytes, checksum: 09225af0315071627118074737e4ebda (MD5) Previous issue date: 2008-02-01 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The reasons of multiple and long successive mates accomplished by Podisus nigrispinus (Dallas) (Hem.: Pentatomidae) males has been unknown. Thus, mating behavior of P. nigrispinus was investigated as function of male body size (i), previous mating status (ii), risk of predation (iii), interrupted mating (iv), and spermatogenesis (v). The female choice for mating with large or small body size males was investigated under three conditions: multiples choice within a population of large and small males; partial choice (ca. only one pair of small and large male) and no choice (only small or large male). Time to initiate a copula and its duration was observed after pairing males and females under the risk of predation imposed by the presence of the predatory wasp Polistes versicolor Oliver (Hym.: Vespidae). Furthermore, females had their reproductive success evaluated with interrupted mating at different intervals (30, 60, 120 and 240 minutes afterinitiating a mating) and when mating with males previously mated. The spermatogenesis of these mated and unmated males was investigated. The outcomes show that P. nigrispinus female mates with males disregarding their body size, previous mating status and, exhibits no mating partner preference in successive mates. In addition, duration of mating, partner choice and female fertility were not influenced by male body size. The risk of predation did not alter mating behavior and duration of mating. However, females with interrupted mating at 30, 60, 120 and 240 minutesexhibited low egg viability (0, 3.1, 7.7, and 34%, respectively) compared to females with uninterrupted mating (338 to 671 minutes) that showed egg viability of 74.2%. The dissection of males of different mating status shows that P. nigrispinus exhibits continuous spermatogenesis and absence of a storage seminal vesicle. Spermatozoa were present in the lumen of the vas deferents independent of mating status. The spermatheca does not change size according to the duration of mating, although its duct exhibited elasticity with significant deformation after mating for 30 minutes. Females under uninterrupted mating exhibited spermathecal duct fully expanded and spermatheca filled with spermatozoa. Based on the results, the reproductive success of P. nigrispinus male is related to the duration of copula and female requires multiple mates to fill spermatheca with spermatozoa. However, the reproductive success of the species does not depend on males’ body size and their mating status. / A realização de múltiplas e longas cópulas por Podisus nigrispinus (Dallas) (Hem.: Pentatomidae) tem sido uma incógnita. Assim, este trabalho teve como objetivo investigar o comportamento reprodutivo de macho de P. nigrispinus. A cópula foi estudada em função do tamanho do macho, status prévio de acasalamento do macho e risco de predação (i). Também, foram analisados a espermatogênese e o efeito do tempo de cópula na transferência de espermatozóides para fêmeas (ii), bem como foram descritas a espermateca e estruturas relacionadas quanto à morfologia interna e modificações ocorridas durante a cópula (iii). A escolha da fêmea por machos virgens ou previamente acasalados foi estudada sob chance múltipla, parcial ou sem chance de escolha por machos grandes ou pequenos. O comportamento para o acasalamento e duração da cópula sob risco de predação [presença de Polistes versicolor Oliver (Hym.: Vespidae)] foi comparado com casais sem risco de predação. Fêmeas tiveram osucesso de fertilização e inseminação avaliado através da interrupção da cópula após 30, 60, 120 e 240 minutos. Em função do status de acasalamento, machos foram dissecados e investigados quanto a produção e transferência de espermatozóides para as fêmeas. Os resultados mostram que o acasalamento em P. nigrispinus independe do tamanho e status prévio de acasalamento dosmachos, além de não apresentar preferência de parceiro. A duração da cópula, escolha do parceiro e a fertilidade das fêmeas não sofrem influência do tamanho do macho. Também, o risco de predação não alterou o comportamento de acasalamento e duração de cópula. Fêmeas com cópulas interrompidas após 30, 60, 120 e 240 minutos apresentaram baixa viabilidade de ovos (0; 3,1; 7,7; e 34%, respectivamente), enquanto aquelas sem interrupção de cópula (338 a 671 minutos) obtiveram 74,2% de viabilidade de ovos. Também, foi observado que machos possuem espermatogênese contínua e ausência de vesícula seminal. A análise do ducto deferente mostra espermatozóides presentes no seu lúmen independente do status de acasalamento (machos virgens, 0h, 12h ou 24h após término da cópula). Em fêmeas, o volume da espermateca não sofre alteração com a cópula. Contudo, ocorre mudança de formato do ducto elástico da espermateca a partir de 30 minutos do início da cópula. Fêmeas que tiveram cópula sem interrupção apresentaram espermatecas completamente preenchidas com espermatozóides. Para P. nigrispinus o sucesso de inseminação e fertilização de fêmeas é dependente da duração da cópula e de múltiplas cópulas. Por outro lado, o sucesso reprodutivo não depende do tamanho do macho e de seu status de acasalamento.
497

Itinerários de uma identidade territorial na invenção do ser tocantinense / Itineraries of a territorial identity in the invention of being tocantinense

Brito, Eliseu Pereira de 07 November 2016 (has links)
Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2016-12-02T17:19:13Z No. of bitstreams: 2 Tese - Eliseu Pereira de Brito - 2016.pdf: 7408438 bytes, checksum: 213b9f2628c43354743987f391be8a02 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2016-12-13T15:31:09Z (GMT) No. of bitstreams: 2 Tese - Eliseu Pereira de Brito - 2016.pdf: 7408438 bytes, checksum: 213b9f2628c43354743987f391be8a02 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-12-13T15:31:09Z (GMT). No. of bitstreams: 2 Tese - Eliseu Pereira de Brito - 2016.pdf: 7408438 bytes, checksum: 213b9f2628c43354743987f391be8a02 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-11-07 / This thesis has as its central theme the identity forged in the territorial relations, discussed under the bias of Human Geography. Territory and identity were analyzed in order to seek answers to the central research problem on the existence of a “territorial tocantinense identity”. This study aimed to analyze the constitution of territorial identity in the interface with territory formation as identification and differentiation of/in the spaces by multiple tocantinenses subjects. The approach proposed in the thesis is a qualitative study, using primary and secondary sources, interviews, historical documents and census information. We used techniques from Diagnóstico Rural Participativo – DRP for data collection through interviews and description of Tocantins’ landscapes in fieldwork. Such data were read by means of discourse analysis based on Nogueira (2001), and the territory was interpreted with basis on geosymbolism proposed by Bonnemaison (1987). It was considered that the first rupture of the territory of Goiás was in 1736, and it was the main framework of the territorial differentiation process. Ruptures in 1809 and 1821 were the result of a non-unified goiana identity. The subjects of the north of Goiás started to be called the nortenses by those from the south, who, in turn, were called the goianos. The territorial singularities created in the midst of a different world in the north of Goiás intensified over the XIX and XX centuries, and in 1956, under the Feliciano Braga command in Porto Nacional, the nortenses became the tocantinenses, which resulted in the creation of the state of Tocantins, in 1988. The mobility through the territory, the paths, places of work and leisure had their importance identified within in the formation of Tocantins’ territorial identity. Therefore, the Tocantins territorial identity is multiple and open to new territorial content, which forms a diachrony in the process. But also, there is a temporal duration of the identity process, which we identified as a persistence / Esta tese tem como temática central a identidade forjada nas relações territoriais, discutida sob o viés da Geografia Humana. Território e identidade foram analisados a fim de buscar respostas ao problema central da pesquisa sobre a existência de uma “identidade territorial tocantinense”. Objetivou-se analisar a constituição da identidade territorial na interface da formação do território enquanto identificação e diferenciação dos/nos espaços por múltiplos sujeitos tocantinenses. A abordagem proposta na tese é de uma pesquisa qualitativa, com uso de fontes primárias e secundárias, entrevistas, documentos históricos e informações censitárias. Utilizou-se de técnicas do Diagnóstico Rural Participativo – DRP para coletas de informações por meio de entrevistas e para descrição da paisagem tocantinense, em campo. Essas informações foram lidas por meio da análise do discurso em Nogueira (2001) e o território foi interpretado como uma trama geossimbólica, conforme proposto por Bonnemaison (1987). Considerou-se que a primeira cisão do território goiano foi em 1736, sendo esta o marco principal do processo de diferenciação territorial. As rupturas de 1809 e 1821 foram resultado de uma não identidade goiana unificada. Os sujeitos do norte de Goiás passaram a ser chamados de nortenses em relação aos do sul, chamados, por sua vez, de goianos. As singularidades territoriais criadas no bojo de um mundo diferenciado no norte de Goiás se intensificaram ao longo dos séculos XIX e XX e, em 1956, sob o comando de Feliciano Braga, em Porto Nacional, os nortenses foram denominados de tocantinenses, intento que permaneceu com a criação do Tocantins, em 1988. A mobilidade espacial, os caminhos, os lugares do trabalho e do ócio foram identificados sua importância na formação da identidade territorial tocantinense. Para tanto, a identidade territorial tocantinense é múltipla e aberta a novos conteúdos territoriais, o que forma uma diacronia no processo. Mas, também, há uma duração temporal do processo identitário, identificado na tese como identidade de persistência.
498

La durée de protection en droit d'auteur et droits voisins / Duration of protection in droit d’auteur and droits voisins

Bélot, Dimitri 13 July 2017 (has links)
Le modèle de protection des oeuvres de l’esprit, qu’il s’agisse du copyright ou du droit d’auteur, estaujourd’hui vivement critiqué. Notamment concernant sa durée. Pourquoi applique-t-on aujourd’huiune durée de protection de principe de soixante-dix ans post mortem auctoris aux oeuvres de l’espriten France, en Europe et aux Etats-Unis ? Et quels sont les enjeux actuels d’une telle durée de laprotection à l’heure d’internet et des contenus dématérialisés ?Pour répondre à ces questions, il est nécessaire de « déconstruire » historiquement et juridiquementle modèle, afin de comprendre l’application actuelle d’une durée de protection de principe desoixante-dix ans post mortem auctoris aux oeuvres de l’esprit.S’il est également primordial de comprendre les évolutions récentes des délais de computation etnotamment les différentes prorogations de la durée de protection, il est aussi fondamental d’étudierl’élargissement du champ d’application du copyright et du droit d’auteur à certains types d’oeuvrestels que le logiciel ou la base de données.La volonté des lobbyistes de la culture et de nombreux ayants droit de proroger la protection desoeuvres de l’esprit participe à la tendance actuelle d’une durée de protection toujours plus longue. Ily a donc urgence, et revaloriser de manière concrète le domaine public est aujourd’hui capital.L’analyse économique du modèle prouve que la durée de protection des oeuvres de l’esprit,aujourd’hui particulièrement longue au regard des outils technologiques actuels, freine la diffusiondu savoir sans toutefois augmenter l’incitation à la création Ainsi, le modèle de protection doit êtreanalysé et repensé, aussi bien juridiquement qu’économiquement, afin qu’une réforme concrète soitproposée. / The model of protection of works, whether is copyright or droit d’auteur, is now strongly criticized.Particularly regarding its duration. Why do we now have a seventy years post mortem auctoristerm of protection of in France, in European Union and in the United States? In an era ofconstantly evolving Internet and dematerialized contents what are the risen current challenges forsuch a period of protection?Answering these questions requires historical and legal "deconstruction" of the model in order toapprehend the current application of a term of protection of seventy years post mortem auctoris tothe works.While it is also important to understand recent developments in computation time, and in particularthe different extensions of the term of protection, it is also fundamental to study the extension of thescope of copyright and droit d’auteur to certain types of works such as software or database.Cultural lobbyists and many right holders play an important part in the current trend of an everlonger protection period. Therefore reasserting the value of public domain is now not only urgent,it’s capital. The economic analysis of the model shows that the duration of protection of works,which is today particularly long with regard to the current technological tools, impedes the spreadof knowledge without, however, increasing the incentive to create. Thus, the protection model needsto be analyzed and rethought, both legally and economically, so that concrete reform of this modelcan be proposed.
499

Adolescents' sleep in a 24/7 society : Epidemiology and prevention

Bauducco, Serena January 2017 (has links)
Sleep undergoes important changes during adolescence and many teenagers experience problems sleeping. These in turn affect adolescents´ academic, physical and psychosocial functioning. Moreover, there are some indications that sleep problems in this age group may be increasing, possibly as a consequence of societal changes, e.g., internet availability. Research on adolescents´ sleep is growing, but more epidemiological studies are needed to clarify the prevalence of poor sleep, long and short-term outcomes associated with it, and potential risk and protective factors to target in preventive interventions. The aim of this dissertation was to contribute to each of these goals; Study I investigated the longitudinal association between sleep problems, defined as symptoms of insomnia, and school absenteeism; Study II explored the prevalence of poor sleep, defined as sleep deficit, in an adolescent population and psychosocial and contextual factors associated with it, including emotional and behavioral problems, stress, sleep hygiene and technology use; finally, Study III evaluated the short-term effects of a novel universal school-based intervention to improve adolescents´ sleep health. The findings show that poor sleep was strongly related to adolescents´ functioning, including emotional and behavioral problems and school attendance, and that sleep deficit was prevalent in adolescents. This supports the need for prevention. Moreover, sleep deficit was associated with stress, technology use and arousal at bedtime, which may represent important barriers to sleep. A preventive intervention targeting these barriers to promote adolescents´ sleep health was successful with the individuals most at risk. However, it remains to be seen whether these changes will be maintained after the intervention and whether incidence of sleep problems will be lower relative to a control group. Implications for theory and practice are discussed.
500

Projektledning i korta projekt : Observationer av projektledares arbete i multiprojektmiljö / Project Management in Short-Duration Projects : Observations of Project Managers’ Work in a Multi-Project Environment

Nilsson, Andreas January 2004 (has links)
As most of the project management models were developed for larger projects, there is a lack of understanding of what project managers in short duration projects do. Short-duration projects are projects in multi-project environments lasting for a number of weeks rather than a number of months. Even if they are common today, short-duration projects have not yet attracted the interest of project researchers. The present study aims to analyze what the project managers in short duration projects do and to develop a method for studying the project managers at work. A theoretical framework is built on earlier studies of managers’ work, suggesting three areas having impact on the project manager’s work. The impacting areas are the project, the project manager’s experience, and the organizational context of the project. The project manager and the assisting project manager were studied while managing a sub-project in a greater telecom system project. The project managers were studied one week each using participant observation and interviews. The findings indicate that much of the time at work was spent in meetings of different kinds, to deal with change, and to guard the production teams from being disturbed by changes in the environment. It was also found that studying a multi-project environment from the sub-project’s perspective gives a different view on multi-project environments that have earlier been presented as the project managers in the short-duration project constantly have to adjust to changes, inputs and demands from the surrounding projects and functional organizations. In the end some proposals on directions for further studies of managers of short-duration projects are made.

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