La tendance actuelle des réseaux de capteurs sans fil est d'avoir un seul réseau supportant plusieurs applications et fournissant plusieurs QoS. Dans cette thèse, nous étudions les techniques de cross-layering afin d'améliorer les performances et de fournir de la QoS. Tout d'abord, nous généralisons le concept de la méthode d'accès MaCARI en proposant une architecture multi-couches où plusieurs combinaisons de protocoles MAC-routage sont utilisées. Une file d'attente est associée à chaque combinaison, et chaque combinaison est activée pour une période précise. Le but est de profiter de ces combinaisons pour offrir différentes QoS. Cependant, cette architecture cause un problème de dimensionnement des périodes, ce qui a un impact sur les performances du réseau. Nous proposons, ensuite, des techniques de cross-layering en échangeant les paquets entre les différentes files d'attente afin de résoudre le problème de dimensionnement. Durant sa période, chaque combinaison traite tous les paquets de sa file d'attente ainsi que les paquets des files d'attente d'autres périodes. Nous montrons par simulation que notre approche améliore les performances du réseau.

Mémoire (M.Ress.Renouv.)--Université du Québec à Chicoutimi, 1991. / Document électronique également accessible en format PDF. CaQCU

Made available in DSpace on 2014-08-20T13:44:27Z (GMT). No. of bitstreams: 1 dissertacao_cezar_tibola.pdf: 387820 bytes, checksum: caab51acd9c0263dbde6805435e79bec (MD5) Previous issue date: 2010-12-22 / The arrangement in the field of soybean plants may contribute to increased productivity. However much of the soybean has responded differently to row spacing. This study has the objective of evaluating the effect of row spacing on yield components of soybean. The experiment was conducted in Manoel Ribas, Paraná state, located in the central 24º28'39,9'' region of the state. The experimental design was in a random blocks. As a split split-plot with four replications. Plots consisted of spacing s (15 cm, 30 cm, 40 cm e 60cm) between rows and plots of the cultivars (BRS 206 and CD 232). The agronomic evaluations were plant height (PH), stem diameter (DC) number of pods per plant (NPP), number of seeds per pod (NSV), 1000 grain weight (P100G), percentage of lodging (AC) and productivity (PROD). The analysis of variance indicated significant interaction of spacing vs. cultivate to DC, NVP, NSV, P100G and productivity. In all spaces cultivar BRS 232 was higher in the NVP and P100G, and also row spacing of 15cm promoted increase of 2.7% in productivity in relation to CD 206. The regression study showed that both CD 206 and BRS 232, when planted to reduced row spacing have a significant linear response (R2 = 1) for lodging, and inversely proportional to NPP (R2 = 0.99) and productivity (R2 = 0.96). In addition, correlation analysis indicates that the height is positively correlated with lodging (r = 0.73), and the lodging negatively affects productivity (r = -0.77). Therefore it is concluded that the cultivars responded differently to spacing. However, both experienced significant fluctuations in the final yield. / O arranjo de plantas pode contribuir com aumento de produtividade, sendo que as cultivares de soja tem respondido de forma diferenciada aos espaçamentos. O presente trabalho teve como objetivo avaliar o efeito do espaçamento entre linhas sobre os componentes de produção de cultivares de soja. O experimento foi conduzido no município de Manoel Ribas PR, localizado na região central do estado. O delineamento experimental foi de blocos ao acaso com parcelas subsubdivididas e quatro repetições. As parcelas foram constituídas dos espaçamentos de (15 cm, 30 cm, 45 cm e 60 cm) entre linhas e as subparcelas das cultivares (CD 206 e BRS 232). As características agronômicas avaliadas foram altura de planta (AP), diâmetro caulinar (DC) número de vagens por planta (NVP), número de sementes por vagem (NSV), peso de 100 grãos (P100G), percentagem de acamamento (AC) e produtividade. A análise de variância indicou efeito significativo na interação de espaçamento vs. cultivar para DC, NVP, NSV, P100G e produtividade. Em todos os espaçamentos a cultivar BRS232 foi superior no NVP e P100G, e também no espaçamento de 15 cm promoveu incremento de 2,7% na produtividade em relação a CD 206. O estudo de regressão indicou que tanto a cultivar BRS232 quanto CD 206, quando submetidas à redução de espaçamento, apresentam resposta linear significativa (R2=1) ao acamamento, e inversamente proporcional ao NVP (R2=0,99) e produtividade (R2=0,96). Além disto, a análise de correlação indicou que a altura esta correlacionada positivamente ao acamamento com (r=0,73), e o acamamento afeta, negativamente, a produtividade (r= 0,77). Portanto conclui-se que as cultivares responderam de forma diferenciada aos espaçamentos. No entanto, ambas sofreram oscilações significativas no rendimento final.

This master‘s thesis deals with design adjustment of spark ignition combustion engine, which might offer larger share of recirculated exhaust gases in cylinder for reaching a large number of benefits that exhaust gas recirculation can offer. The introductory theoretical part describes exhaust gas recirculation and its influence on spark ignition combustion engine. In the following part the methods of mixture layering and types of intake ports are described. Further design of spiral intake port is made based on calculations. Capability of mixture layering is valuated by numerical simulation. Flow properties of intake ports are compared to production version by an experiment on flow station.

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See file 01 / Art History, Visual Arts & Music / (M.A. (Visual Arts))

The study involved BTec National (level 3) engineering students studying at a large Further Education College in the South West region. The disciplines of Electrical/Electronic, Mechanical, Operations and Maintenance, Manufacturing, Telecommunications and Fabrication where all included in the study. Several students were sent by their employers on day release programmes and apprenticeships, and these formed the majority of the part time students. There were also other employed students who attended full time for terms 1 and 3 as part of a block release programme. The remaining students were full time, and mainly 16-18 years old. The study focused upon the core mathematics module everyone studied, and mathematical resources which were available through a virtual learning environment. The resources used layering, enabling earlier work to be built on and applied. Two separate cohorts were studied after substantial changes had been made to the qualification standards. The main findings were that the mathematics resources were very useful support, had a significant positive impact on student success, and enhanced the student experience. They helped part time students, especially, to improve their confidence and their achievements. The unlimited availability of these resources were a major consideration in their usefulness. The use of layering within the mathematics unit enabled better recall and comprehension.

En mai 2009, l’Ontario a adopté la Loi sur l’énergie verte et devint ainsi la première juridiction en Amérique du Nord à promouvoir l’énergie renouvelable par le biais de tarifs de rachat garantis. En novembre 2010, dans son Plan énergétique à long terme, la province s’est engagée à déployer 10,700 MW en capacité de production d’énergie renouvelable non-hydroélectrique par 2018. Il s’agit de la cible de déploiement la plus élevée dans ce secteur au Canada. Les infrastructures de production et de distribution d’électricité comprennent des coûts d’installation élevés, une faible rotation des investissements et de longs cycles de vie, facteurs qui servent habituellement à ancrer les politiques énergétiques dans une dynamique de dépendance au sentier. Depuis le début des années 2000, cependant, l’Ontario a commencé à diverger de sa traditionnelle dépendance aux grandes centrales hydroélectriques, aux centrales à charbon et aux centrales nucléaires par une série de petits changements graduels qui feront grimper la part d’énergie renouvelable dans le mix énergétique provincial à 15% par 2018. Le but de ce mémoire est d’élucider le mécanisme de causalité qui a sous-tendu l’évolution graduelle de l’Ontario vers la promotion de l’énergie renouvelable par le biais de tarifs de rachat garantis et d’une cible de déploiement élevée. Ce mémoire applique la théorie du changement institutionnel graduel de Mahoney et Thelen au cas du développement de politiques d’énergie renouvelable en Ontario afin de mieux comprendre les causes, les modes et les effets du changement institutionnel. Nous découvrons que le contexte canadien de la politique énergétique favorise la sédimentation institutionnelle, c’est-à-dire un mode changement caractérisé par de petits gains favorisant l’énergie renouvelable. Ces gains s’accumulent pourtant en transformation politique importante. En Ontario, la mise sur pied d’une vaste coalition pour l’énergie renouvelable fut à l’origine du changement. Les premiers revendicateurs de politiques favorisant l’énergie renouvelable – les environnementalistes et les premières entreprises d’approvisionnement et de service en technologies d’énergie renouvelable – ont dû mettre sur pied un vaste réseau d’appui, représentant la quasi-totalité de la société ontarienne, pour faire avancer leur cause. Ce réseau a fait pression sur le gouvernement provincial et, en tant que front commun, a revendiqué l’énergie renouvelable non seulement comme solution aux changements climatiques, mais aussi comme solution à maints autres défis pressants de santé publique et de développement économique. La convergence favorable d’un nombre de facteurs contextuels a certes contribué à la réussite du réseau ontarien pour l’énergie renouvelable. Cependant, le fait que ce réseau ait trouvé des alliés au sein de l’exécutif du gouvernement provincial s’est révélé d’importance cruciale quant à l’obtention de politiques favorisant l’énergie renouvelable. Au Canada, les gouvernements provinciaux détiennent l’ultime droit de veto sur la politique énergétique. Ce n’est qu’en trouvant des alliés aux plus hauts échelons du gouvernement que le réseau ontarien pour l’énergie renouvelable a pu réussir. / In May 2009, Ontario adopted the Green Energy and Green Economy Act and became the first jurisdiction in North America to promote renewable energy through advanced feed-in tariffs. In November 2010, in its Long-Term Energy Plan, the province pledged to deploy 10,700 MW of non-hydroelectric renewable energy capacity by 2018, the highest such target in Canada. Electricity production and distribution infrastructure is characterized by high setup costs, low capital stock turnover and long life spans, factors that traditionally entrench energy policy in path-dependent trajectories. Since the early 2000’s, however, Ontario has diverged from its historic reliance on large hydro, coal and nuclear through a series of gradual policy shifts set to expand renewable energy’s share in the overall supply mix to 15% by 2018. The purpose of this thesis is to uncover the causal mechanism behind Ontario`s gradual shift toward the promotion of renewable energy through advanced feed-in tariffs, accompanied by high deployment targets. The thesis applies Mahoney & Thelen’s theory of gradual institutional change to the case of renewable energy policy development in Ontario, providing new insight into the causes, modes and effects of institutional change. The thesis finds that the Canadian energy policy context favors a layering pattern of change, characterized by small, yet cumulative, renewable energy policy gains. The driving force of this process involves coalition building. To achieve renewable energy policy gains, Ontario`s first renewable energy proponents, mostly environmental groups and early renewable energy supply and service firms, had to build a wide-ranging, multi-stakeholder network of allies and lobby government from a unified front, presenting renewable energy as a solution not only to climate change but a combination of other immediately pressing public health and economic challenges. Elements of timing greatly aided the renewable energy network’s campaign. Ultimately, however, the thesis finds that, given provincial governments` ultimate veto power over energy policy, finding allies in the top echelons of government was most crucial to the renewable energy network`s success.

A variabilidade das propriedades físicas do solo apresenta impacto sobre o desempenho das atividades de produção agrícola. Métodos indiretos para obtenção de informações sobre as propriedades do solo com interesse agronômico são utilizados com o intuito de favorecer o uso de insumos de modo mais adequado. A condutividade elétrica aparente do solo (CEa) é influenciada por diversas propriedades, muitas delas interrelacionadas e com variabilidade em curta distância, sendo difícil a separação dos diversos fatores. As medidas de CEa são usualmente tomadas em superfície com arranjos de eletrodos para prospecção de um volume de solo proporcional à distância entre eles. Neste trabalho foi utilizada uma metodologia que permitiu identificar algumas das propriedades com maior impacto sobre a CEa, merecendo destaque aquelas relacionadas ao espaço poroso do solo. A caracterização detalhada da variação da CEa ao longo do perfil do solo e sua comparação com aquela obtida a partir da sondagem elétrica vertical permitiram identificar algumas limitações desta técnica. A presença de camadas com variação de diversas propriedades físicas e de umidade no perfil do solo alterou os valores observados em superfície. A relação entre a distância de separação dos eletrodos no arranjo com quatro pontas igualmente espaçadas, e a profundidade de prospecção, coeficiente k, oscilou entre 0,35 e 0,70 para os solos LVd, LAd e PVe avaliados. A sondagem elétrica empregada na caracterização de variabilidade espacial na horizontal e em profundidade em uma área com teores de argila oscilando entre 150 e 379 g kg-1 na camada 0 a 0,2 m e entre 225 e 326 g kg-1 na camada 0,6 a 0,8 m apresentou resultado satisfatório. / The variability of soil physical properties has an impact on the performance of agricultural production activities. Indirect methods for obtaining information on the soil properties with agronomic interest are used to allow the use of inputs more appropriately. The apparent soil electrical conductivity ( ECa ) is influenced by several properties , many of them interrelated and presenting variability in short distances, being difficult to separate the various factors. ECa measures are usually taken in surface, using electrode arrangements for prospecting a soil volume proportional to the distance between them. In this work, a methodology was used that identified some of the properties with the greatest impact on the ECa, with emphasis to those related to soil porous space. The detailed characterization of the variation of ECw throughout the soil profile and its comparison with that obtained from the vertical electrical sounding was carried to identify certain limitations of this technique. The presence of several layers with varying physical properties and moisture in the soil profile changed values obtained from surface sounding. The relationship between the separation of the electrodes in the array with four points equally spaced, the Wenner array, and the depth of exploration, coefficient k, ranged between 0.35 and 0.70 for the soils LVd , LAd PVe and evaluated. A survey was done for the ECa characterization of spatial variability in the horizontal and along soil profile in an area with clay content ranging from 150 to 379 g kg - 1 in the layer from 0 to 0.2 m and between 225 and 326 g kg - 1 in layer 0, 6 to 0.8 m. The use of ECa for characterizing this variability showed satisfactory results.

In this thesis, we consider wireless ad hoc and sensor networks where energy matters. Indeed, sensor nodes are characterized by a small size, a low cost, an advanced communication technology, but also a limited amount of energy. This energy can be very expensive, difficult or even impossible to renew. Energy efficient strategies are required in such networks to maximize network lifetime. We distinguish four categories of strategies: 1. Energy efficient routing, 2. Node activity scheduling, 3. Topology control by tuning node transmission power and 4. Reduction of the volume of information transferred. Our contribution deals with energy efficient routing and node activity scheduling. For energy efficient routing, the idea consists in reducing the energy spent in the transmission of a packet from its source to its destination, while avoiding nodes with low residual energy. The solution we propose, called EOLSR, is based on the link state OLSR routing protocol. We show by simulation that this solution outperforms the solution that selects routes minimizing the end-to-end energy consumption, as well as the solution that builds routes based on node residual energy. We then show how we can improve the benefit of energy efficient routing using cross layering. Informa- tion provided by the MAC layer improves the reactivity of the routing protocol and the robustness of routes. Moreover, taking into account the specificities of some applications like data gathering allows the routing protocol to reduce its overhead by maintaining routes only to the sink nodes. Concerning node activity scheduling, since the sleep state is the least power consuming state, our aim is to schedule node state between sleeping and active to minimize energy consumption while ensuring network and application functionalities. We propose a solution, called SERENA, based on node coloring. The idea is to assign a color to each node, while using a small number of colors and ensuring that two nodes with the same color can transmit without interfering. This color is mapped into a slot in which the node can transmit its messages. Consequently, each node is awake during its slot and the slots granted to its one-hop neighbors. It sleeps the remaining time. We show how this algorithm can adapt to different application requirements: broadcast, immediate acknowledgement of unicast transmissions... The impact of each additional requirement is evaluated by simulation. An originality of this work lies in taking into account real wireless propagation conditions. Color conflicts are then possible. A cross-layering approach with the MAC layer is used to solve these conflicts. We also show how cross-layering with the application layer can improve the coloring per- formance for data gathering applications. This work has been done for the ANR OCARI project whose aim is to design and implement a wireless sensor network for applications in harsh environments such as power plants and war- ships. The network layer including SERENA and EOLSR has been specified and is now under implementation.