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Made available in DSpace on 2019-04-05T23:08:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11-29 / A wireless sensor network (WSN) consists of groups of spatially distributed networked sensors sending data to a sink node, called base station. These sensors are usually strongly resource constrained. In a WSN, collected data are passed from sensor to sensor until the base station is reached. Considering common available bandwidths, large data volumes may produce heavy traffic congestion in WSNs. In this work, we advocate the use of database technology in sensor networks to reduce the amount of data to be transmitted by sensors and consequently the data traffic in the network. Since data communication by means of a wireless medium consumes a lot of energy, reducing data transmitted by sensors can improve significantly the sensor network lifetime. This work presents a query engine for processing queries in WSNs. The main goal of the proposed query engine is to improve significantly the sensor network lifetime. The key feature of the proposed engine is to execute queries in a distributed way through the various sensor nodes of a WSN. Experimental results presented in this work prove the efficiency of the proposed query engine. / Uma rede de sensores sem fio (RSSF) consiste de grupos de sensores em rede, distribuídos espacialmente e enviando dados a um nó sumidouro, denominado estação base. Estes sensores em geral são fortemente limitados em recursos. Em uma RSSF os dados coletados são passados de sensor a sensor até que a estação base seja alcançada. Considerando as larguras de bandas mais comuns disponíveis, grandes volumes de dados podem produzir congestionamento no tráfego das RSSFs. Neste trabalho, defendemos o uso de tecnologias de bancos de dados em redes de sensores sem fio para reduzir a quantidade de dados que devem ser transmitidos e, conseqüentemente, reduzir o tráfego de dados na rede. Pelo fato da comunicação através de um meio sem fio consumir grandes quantidades de energia, reduzir a quantidade de dados transmitidos pelos sensores pode melhorar significativamente o tempo de vida da RSSF. Este trabalho apresenta um mecanismo de processamento de consultas em RSSFs. O principal objetivo do mecanismo proposto é melhorar o tempo de vida útil da RSSF, e tem como característica fundamental à execução de consultas de maneira distribuída através de vários nós sensores. Os resultados experimentais apresentados neste trabalho provam a eficiência do mecanismo proposto.

Tato práce se zabývá aplikací metod a pravidel marketingu ve vyhledávačích na internetovou prezentaci www.archcich.cz. Základním cílem teoretické části je kvantifikování základní teorie marketingu ve vyhledávačích. Praktická část obsahuje aplikaci metod na zlepšení viditelnosti www.archcich.cz

We mainly studied the morphology of GaN structures which were grown by plasma-assisted molecular beam epitaxy. The only condition we changed is Ga/N Ratio. Based on observation of reflection high energy electron diffraction (RHEED) patterns, we found all samples belong to two-dimensional (2D) growth mode. Also, based on scanning electron microscope (SEM) analysis, we found when Ga/N Ratio is 0.13 and 0.18, the surface of sample will be smoothest. Furthermore, based on the roughness result derived from atomic force microscope (AFM), we got the same result. Then we observed the surface of samples after etching, we found all samples belong to Ga-face. Also, we can detect the degree of the state of mismatch under X-ray diffraction analysis. We found when Ga/N Ratio is 0.13, we got the lowest screw dislocation density; and when Ga/N Ratio is 0.18, we got the lowest overall dislocation density. In conclusion, we are trying to find sample growing parameters which could generate both better morphology and better structure.

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Handling of clustered or nested data structures requires the use of multilevel modeling techniques. One such multilevel modeling technique is multilevel structural equation modeling (MLSEM). While estimation of indirect effect parameters and standard errors based on the conventional multilevel model (MMM) has been assessed, this is not the case for the use of the MLSEM model for estimating indirect effects. This simulation study was designed to investigate the use of the MLSEM for estimating mediated effects for the “upper-level” mediation model as compared with the MMM. The following conditions were manipulated: number of clusters (G), within-cluster sample size (nj ), intra-class correlation, measurement error in the mediator, and the true value of the mediated effect derived from various patterns of true values for a and b. The generating model entailed an upper-level mediation model for a cluster-randomized trial that included a dichotomous level two independent variable, a cluster-level latent mediator and an individual-level latent dependent variable both with four indicators. Relative parameter and standard error bias, obtained using the MLSEM and the MMM were evaluated and compared. Percent coverage was calculated and compared when PRODCLIN was used to calculate the confidence interval estimates of the ab effect. Finally, Type I error rates for conditions when ab = 0 were assessed and compared. In addition, statistical power for detecting a truly non-zero mediated effect was tallied and compared across models. Results showed that use of the MMM provided inaccurate and misleading parameter and standard error estimates for the estimates of the mediated effect, especially when the true values of a, b and ab were not zero and the measurement error for M was large. However, the MLSEM estimates were also unacceptable in some of the conditions with small values for G and nj. Researchers are encouraged to use the MLSEM for assessing the multilevel mediated effects when either or both paths a and b are expected to be non-zero, if G is at least 40 and nj is also greater than 40. Results are presented and discussed along with implications for applied researchers intending to assess mediated effect with clustered data. / text

Zugl.: Bamberg, Univ., Diss., 2009.

O objetivo deste estudo foi registrar e analisar narrativas autobiográficas sobre o processo de saída da situação de rua de adultos com esta vivência e que alcançaram uma condição habitacional estável. O instrumento utilizado foi a Entrevista Narrativa Autobiográfica, que consiste em um convite amplo e não-diretivo para que cada participante conte a sua história de vida de forma livre. As narrativas foram transcritas integralmente e codificadas de acordo com três matrizes interpretativas: estruturas autobiográficas; temas de agência/comunhão; e temas de origem êmica. Participaram deste estudo dois adultos, com trajetórias e perfis heterogêneos, que foram contatados em serviços da rede de assistência social. As narrativas analisadas demonstraram a recusa a internalizar estigmas atribuídos à situação de rua, e foram marcadas por temas de controle de si, empoderamento, e cuidado com os outros, retratando transformações pessoais associadas à saída da situação de rua. / The aim of this study was to record and analyze autobiographical narratives about the process exiting homeless of ex-homeless adults who have achieved stable housing. The instrument used was the Autobiographical Narrative Interview, consisting of a broad and non-directive invitation to each participant tell freely his/her life history. The narratives were transcribed and coded according to three interpretive matrices: autobiographical structures; themes of agency / communion; and emic themes. The study included two adults, with heterogeneous paths and profiles, which were contacted among the social care network. The narratives analyzed demonstrated a refusal to internalize stigma attributed to homeless people, and were marked by themes of self-control, empowerment, and care for others, portraying personal transformations associated with the process of exiting homelessness.

O objetivo deste estudo foi registrar e analisar narrativas autobiográficas sobre o processo de saída da situação de rua de adultos com esta vivência e que alcançaram uma condição habitacional estável. O instrumento utilizado foi a Entrevista Narrativa Autobiográfica, que consiste em um convite amplo e não-diretivo para que cada participante conte a sua história de vida de forma livre. As narrativas foram transcritas integralmente e codificadas de acordo com três matrizes interpretativas: estruturas autobiográficas; temas de agência/comunhão; e temas de origem êmica. Participaram deste estudo dois adultos, com trajetórias e perfis heterogêneos, que foram contatados em serviços da rede de assistência social. As narrativas analisadas demonstraram a recusa a internalizar estigmas atribuídos à situação de rua, e foram marcadas por temas de controle de si, empoderamento, e cuidado com os outros, retratando transformações pessoais associadas à saída da situação de rua. / The aim of this study was to record and analyze autobiographical narratives about the process exiting homeless of ex-homeless adults who have achieved stable housing. The instrument used was the Autobiographical Narrative Interview, consisting of a broad and non-directive invitation to each participant tell freely his/her life history. The narratives were transcribed and coded according to three interpretive matrices: autobiographical structures; themes of agency / communion; and emic themes. The study included two adults, with heterogeneous paths and profiles, which were contacted among the social care network. The narratives analyzed demonstrated a refusal to internalize stigma attributed to homeless people, and were marked by themes of self-control, empowerment, and care for others, portraying personal transformations associated with the process of exiting homelessness.