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Optimisation de la transmission d'images dans les réseaux de capteurs pour des applications critiques de surveillance / Optimization of image transmission in wireless sensor networks for mission-critical surveillance applicationsDiop, El hadji Serigne Mamour 17 June 2014 (has links)
L’émergence de petites caméras CMOS et de microphones MEMS, à coût et puissance réduits, a contribué au développement d’une technologie permettant la transmission de flux multimédia (audio, image, vidéo) : les réseaux de capteurs multimédia. Cette technologie, offrant de nouvelles perspectives d’applications potentielles où la collecte d’informations visuelles et/ou acoustiques apporte une plus- value certaine, suscite un intérêt manifeste. Avec des données multimédia, la qualité de service devient désormais une exigence fondamentale pour la transmission dans un environnement contraint en ressources. Dans le contexte spécifique de cette thèse, nous considérons un déploiement par voie aérienne d’une grande quantité de capteurs image pour des applications critiques de surveillance telles que la détection d’intrusion ou des opérations de recherche et sauvetage. La prise en compte de la criticité des applications constitue un aspect important de cette thèse, novateur par rapport aux contributions déjà effectuées dans le domaine. Nos travaux se fondent sur une méthode d’ordonnancement adaptatif de l’activité des capteurs image qui fournit, pour chacun d’entre eux, son ensemble de cover-sets. La détection d’un événement dans le réseau déclenche la transmission d’une large quantité d’informations visuelles, émanant de plusieurs sources pour résoudre les ambiguïtés. L’objectif de cette thèse est d’optimiser cette transmission simultanée d’images causant des désagréments sur le réseau. Nous avons tout d’abord proposé une stratégie de sélection des cover-sets pertinents à activer pour une transmission efficace des images capturées. Cette stratégie, basée sur des critères d’état et de voisinage, assure un compromis entre autonomie et criticité. Une extension multi-chemin de GPSR assure la remontée des images émises des sources sélectionnées au puits. Une seconde contribution, également une approche de sélection, se fonde sur les informations de chemins à 2 sauts pour la sélection des cover-sets. Contrairement à la précédente, elle accorde une priorité à la criticité par rapport à la préservation de l’énergie, même si cette préservation est faite de manière indirecte. Un protocole de routage multi-chemin T-GPSR essentiellement basé sur les informations à 2 sauts est associé à la seconde approche de sélection. Une étude de performances de la mobilité du puits sur les propositions basées sur les informations à 2 sauts constitue notre troisième contribution. / Recent advances of inexpensive and low-power CMOS cameras and MEMS mi- crophones have led to the emergence of Wireless Multimedia Sensor Networks (WMSNs). WMSNs promise a wide spectrum of potential applications which require to ubiquitously capture multimedia content (visual and audio information). To support the transmission of multimedia content in a resource constrained environment, WMSNs may require a certain level of quality of service (QoS) in terms of delay, bandwidth, jitter, reliability, quality level etc. In this thesis, we consider Wireless Image Sensor Networks (WISNs) where sensor nodes equipped with miniaturized visual cameras to provide accurate information in various geographical parts of an area of interest can be thrown in mass for mission-critical applications such as intrusion detection or search & rescue. An innovative and important aspect of this thesis is to take into account the criticality of applications. The network adopts an adaptive scheduling of image sensor node’s activity based on the application criticality level, where each node computes its cover-sets. So, event detection triggers the simulataneous transmission of a large volume of visual data from multiples sources to the Sink. The main objective of this thesis is to optimize this simultaneous transmission of images that can degrade network performance. With this goal in mind, we first proposed a multi-criteria approach to select the suitable cover-sets to be activated for reliable transmission of images in mission-critical applications. The proposed approach takes into account various parameters that affect the image quality at the Sink in a multi-hop transmission network and guarantees a compromise between autonomy and criticality. A modified version of GPSR routing protocol supporting the transmission of multimedia streams ensures the transfer of images from selected sources to the Sink. The second contribution consists in an optimized selection strategy based on 2-hop neighborhood information to determine the most relevant cover-sets to be activated to increase reliability for image transmission. This selection approach prioritizes the application’s criticality. A multipath extension of GPSR, called T-GPSR, wherein routing decisions are based 2-hop neighborhood information is also proposed. A performance study of the sink mobility on proposals based on 2-hop information is our third contribution.
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Regional character of the lower Tuscaloosa formation depositional systems and trends in reservoir qualityWoolf, Kurtus Steven 07 November 2013 (has links)
For decades the Upper Cretaceous Lower Tuscaloosa Formation of the U.S. Gulf Coast has been considered an onshore hydrocarbon play with no equivalent offshore deposits. A better understanding of the Lower Tuscaloosa sequence stratigraphic and paleogeographic framework, source-to-sink depositional environments, magnitude of fluvial systems, regional trends in reservoir quality, and structural influences on its deposition along with newly acquired data from offshore wells has changed this decades-long paradigm of the Lower Tuscaloosa as simply an onshore play.
The mid-Cenomanian unconformity, underlying the Lower Tuscaloosa, formed an extensive regional network of incised valleys. This incision and accompanying low accommodation allowed for sediment bypass and deposition of over 330 m thick gravity-driven sand-rich deposits over 400 km from their equivalent shelf edge. Subsequently a transgressive systems tract comprised of four fluvial sequences in the Lower Tuscaloosa Massive sand and an overlying estuarine sequence (Stringer sand) filled the incised valleys. Both wave- and tide-dominated deltaic facies of the Lower Tuscaloosa are located at the mouths of incised valleys proximal to the shelf edge. Deltaic and estuarine depositional environments were interpreted from impoverished trace fossil suites of the Cruziana Ichnofacies and detailed sedimentological observations. The location and trend of valleys are controlled by basement structures.
Lower Tuscaloosa rivers were 3.8m – 7.8m deep and 145m – 721m wide comparable to the Siwalik Group outcrop and the modern Missouri River. These systems were capable of transporting large amounts of sediment indicating the Lower Tuscaloosa was capable of transporting large amounts of sediments to the shelf edge for resedimentation into the deep offshore.
Anomalously high porosity (>25%) and permeability (>1200md) in the Lower Tuscaloosa at stratigraphic depths below 20,000 ft. are influenced by chlorite coating the detrital grains. Chlorite coatings block quartz nucleation sites inhibiting quartz cementation. Chlorite coats in the Lower Tuscaloosa are controlled by the presence and abundance of volcanic rock fragments supplying the ions needed for the formation of chlorite. Chlorite decrease to the east in sediments derived from the Appalachian Mountains. An increase in chlorite in westward samples correlates with an increase of volcanic rock fragments derived from the Ouachita Mountains. / text
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Investigation of novel techniques to overcome the challenges of mitral isthmus ablation in the treatment of atrial fibrillationWong, Kelvin Cheok Keng January 2013 (has links)
No description available.
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Untersuchungen zum Blatt- und Wurzelmetabolismus sowie zum Phloem- und Xylemtransport in Zusammenhang mit der Stickstoff-Effizienz bei Raps (Brassica napus L.) / Study on nitrogen efficiency of oilseed rape (Brassica napus L.) in relation to the metabolism in leaves and roots and to the transport in phloem and xylemZhou, Zewen 02 November 2000 (has links)
No description available.
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Harnessing the anabolic properties of dark respiration to enhance sink activity at elevated CO2 using Arabidopsis thaliana L. with partially-suppressed mitochondrial pyruvate dehydrogenase kinaseWeraduwage, Sarathi 17 May 2013 (has links)
Sink limitations in plants reduce the potential for photosynthesis and yield, particularly under conditions that favour enhanced source activity such as elevated CO2 (EC). Dark respiration, considered catabolic, has rarely been exploited to enhance sink activity in plants. Arabidopsis thaliana L. lines with partially-suppressed mitochondrial pyruvate dehydrogenase (mtPDH) kinase (mtPDHK), a negative post-translational regulator of the mtPDH complex, was shown previously to have both elevated mtPDH complex activity and increased seed weight and oil content at ambient CO2 (AC), suggesting an enhancement of sink activity. The mtPDH links glycolysis with the tricarboxylic acid (TCA) cycle. It was hypothesized that Arabidopsis having suppressed mtPDHK will display their greatest plant productivity at EC through a combined enhancement of source and sink activities. Control and transgenic Arabidopsis having either constitutive or seed-specific expression of antisense mtPDHK were grown at either AC or EC. Expression of mtPDHK and mtPDH complex activity in rosette leaves and reproductive tissues were measured, which required the development of an assay to quantify mtPDH activity. Vegetative and reproductive growth over time, seed oil
parameters, and leaf net C exchange were also quantified. A parabolic relationship was found between mtPDHK expression and mtPDH activity, reflecting a role for mtPDH in balancing photosynthetic and respiratory processes. A number of growth and seed oil parameters were improved in transgenic lines, particularly at EC; many of these parameters showed a
significant linear or quadratic correlation with mtPDHK expression and mtPDH activity. The proportion of very long chain fatty acids was increased in transgenic lines. Leaf net C exchange was enhanced at AC and EC, and particularly in lines showing repression of mtPDHK. The greatest enhancement in total seed and oil productivity was found for the constitutive lines 104 and 31 at EC (up to 2.8 times). These two lines exhibited a significant increase in inflorescence size, an increase in leaf water use efficiency, the lowest rate of mtPDH complex inactivation by ATP, and an intermediary enhancement of mtPDH complex
activity in seeds. Thus, it is concluded that the mtPDH plays a key role in regulating sink and source activities in plants. / Natural Sciences and Engineering Research Council (NSERC) through the Green Crop Networks Research Network; Ontario Graduate Scholarship;
Syngenta Graduate Scholarship; Ball Farm Services and Agrico Canada Ltd. Scholarship; Mrs. Fred Ball Scholarship; Arthur D. Latornell Scholarship; Hoskins Scholarship; Robb Travel Grant; Registrars and the Deans Scholarship and travel awards and bursaries from the University of Guelph, and the Ontario Agricultural College.
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Modélisation de fermes de systèmes houlomoteurs : effets d’interactions entre systèmes à l’échelle de la ferme et impact sur le climat de vagues à l'échelle régionale / Numerical modeling of arrays of wave energy converters : interaction effects between units at the scale of an array and impact on wave climatology at the regional scaleCharrayre, François 17 September 2015 (has links)
Cette thèse porte sur le développement d'un ensemble d'outils numériques destinés à simuler différents aspects des interactions vagues-structure appliquées à l'exploitation des systèmes de récupération de l'énergie des vagues (SREV). Elle a été réalisée dans le cadre du projet ANR Monacorev (projet ANR11-MONU-018-01, 2012-2015).L'objectif est de pouvoir traiter la question des interactions à l'échelle d'une ferme de SREVs (≈ 1 km), et d'étudier l'impact d'une ou plusieurs fermes de SREVs à l'échelle régionale (≈ 10km) sur le champ de vague total. Des méthodes de modélisation et de simulation adaptées sont développées pour chacune de ces deux échelles. Jusqu'à présent, les interactions entre les SREVs étaient bien souvent étudiées en considérant que le fond était plat (l'influence d'un fond variable sur le champ de houle au niveau de la ferme étant alors jugé négligeable), ce qui permet de calculer facilement et rapidement le champ de vagues et les interactions grâce à l'utilisation de la théorie linéaire potentielle. Une application pratique de cette méthode est le calcul du rendement d'une ferme de SREVs, et l'optimisation de leurs positions relatives au sein d'un parc. Dans le cadre de la théorie linéaire, cette thèse propose une méthodologie de couplage originale entre un code de tenue à la mer (Aquaplus) et un code de propagation de la houle en zone côtière (Artemis), laquelle a été développée et qualifiée. Les simulations réalisées montrent que, pour une configuration de ferme de SREVs donnée, on ne peut pas toujours négliger les effets de la bathymétrie. Par exemple, la présence d'une plage de pente 10% au large d'une ferme de SREV peut modifier la hauteur des vagues de manière significative, et affecter ainsi le rendement de la ferme de manière significative par rapport au cas où le fond est uniformément plat. A l'échelle côtière régionale, il est aussi intéressant de simuler et prédire l'impact de fermes de SREVs sur le champ de vagues. Pour des raisons d'efficacité, une approche à phases moyennées de modélisation des vagues a été privilégiée, fondée sur le code spectral d'états de mer Tomawac. La représentation des effets d'un SREV à travers l'utilisation d'un terme puits (concept permettant de soustraire au spectre d'énergie d'état de mer local l'énergie correspondant à celle absorbée par le SREV), bien qu'incomplète du fait que les effets de radiation/diffraction ne sont pas pris en compte, a été étudiée et testée. Une nouvelle méthodologie prenant en compte ces effets dans un code spectral est présentée ici et testée, avec l'objectif de pallier à ces limitations. Les discussions sur la validité de deux approches permettent d'esquisser des pistes de développements ultérieurs pour la représentation des fermes de SREV à l'échelle régionale / This thesis focuses on the development of a set of numerical tools to simulate different aspects of the wave-body interactions applied to the exploitation of wave energy converters (WEC). It was conducted under the ANR Monacorev project (project-ANR11 MONU-018-01, 2012-2015).The objective is to address the issue of the interactions at the scale of a farm of WECs (≈ 1 km), and to study the impact of one or more WEC farms at the regional scale (≈ 10km ) on the total wave field. Modeling and simulation methods adapted for each of these two scales are developed. Until now, the interactions between WECs was often studied by considering that the bottom was flat (the influence of a variable bathymetry on the wave field at the farm site being considered to be negligible), allowing to easily and quickly calculate the wave field and interactions through the use of linear potential theory. A practical application of this method is the yield estimation for a WEC farm and the optimization of the WEC position within a park. In the framework of the linear theory, this thesis proposes an original coupling methodology between a seakeeping (Aquaplus) and a wave propagation code in coastal areas (Artemis), which was developed and qualified. Simulations show that, for a given WEC farm configuration, effects of the bathymetry cannot systematically ignored. For example, the presence of a 10% slope close to a WEC farm can significantly modify the wave height, and thus affect the performance of the farm by several percent compared to the case with a uniformly flat bottom. At the regional coastal scale, it is also interesting to simulate and predict the impact of WEC farms on the wave field. At this scale, for efficiency reasons, a phase-averaged simulation of waves was preferred, based on the sea state spectral code TOMAWAC. The representation of the effects of a WEC through the use of a sink-term (concept for subtracting the energy equivalent to that absorbed by the WEC to the sea state energy spectrum), though incomplete due to the fact that the scattering effects are not taken into account, has been studied and tested. A new methodology taking into account these effects in a spectral code is presented here and tested with the aim to overcome these limitations. Discussions on the validity of these approaches allow us to propose possible future developments for the modeling of WEC farm at the regional scale
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Effect of Favourable Pressure Gradient on Turbulence in Boundary LayersPatwardhan, Saurabh Sudhir January 2015 (has links) (PDF)
This thesis explores the effects of favourable pressure gradient on the structure of turbulent boundary layers (TBL). In this context, the structure of three types of boundary layers namely a zero-pressure-gradient boundary layer, equilibrium boundary layers under favourable pressure gradient and relaminarising boundary layers is investigated mostly from the point of view of large-scale dynamics. This covers a whole range of flows on the so-called Reynolds number - pressure gradient diagram - from turbulent zero pressure gradient flows to relaminarising flows at relatively low Reynolds numbers.
The study of turbulent and relaminarising boundary layers is carried out primarily using direct numerical analyses and some limited experiments in this thesis.
The direct numerical simulations (DNS) of a zero-pressure-gradient turbulent boundary
layer (ZPG TBL) is validated against the experimental and DNS data available in the
literature. Furthermore, the important question of time-averaged signature of a large scale vortex structure and its relation with the two-point correlations in the context of ZPG TBL is addressed. In this context, a synthetic flow consisting of hairpin vortex structures is generated. The two-point correlations in the synthetic TBL and a real TBL are found to be qualitatively similar. This shows that the vortex structure leaves a time-averaged footprint in the form of correlations of velocity and vorticity. A study of two-point correlations in a real TBL shows that the structure angle deduced from two-point correlations varies with wall-normal location. The structure angle is small near the wall and increases away from the wall in agreement with the previous studies. The small angle close to the wall signifies the presence of streamwise structure. Away from the wall, this streamwise coherence is lost and the correlation contours become more
isotropic. The presence of the wall and the mean shear affects smaller scales making
them anisotropic close to the wall. Towards the edge of the boundary layer, smaller
scales tend to become isotropic leading to -5/3 law in the energy spectrum. Further, a
relation between a passive scalar in a flow and vorticity is explored. It is found that the scalar product of vorticity and scalar gradient is conserved in a non-diffusive situation.
This assertion is demonstrated under various flow conditions. Despite the differences in
Schmidt numbers, the structures observed in the outer layer are similar in both numerical
and experimental flow visualisations.
Further, the equilibrium turbulent boundary layers under favourable pressure gradient
are studied. The numerical simulations of equilibrium sink flow TBL are validated
against the experimental results of Dixit (2010). A study of two-point correlations reveals that the near-wall structure angle decreases with a favourable pressure gradient in sink flow TBLs. In the outer region, the loss of streamwise coherence occurs at a wall-normal location closer to the wall than in an ZPG TBL. Edge intermittency study reveals that the flow is non-turbulent beyond y/δ = 0.8 inside the mean boundary layer edge. The variation of the ratio of pressure gradient to Reynolds shear stress gradient shows that this ratio is very large (> 50) beyond y/δ = 0.8. The dominance of pressure gradient makes this part of sink flow TBL to behave like a Euler-region. Small scales in sink flow TBL tend to be isotropic near the edge of the boundary layer and spectra shows -5/3 law akin to ZPG TBL, albeit at lower Reynolds numbers. The concept of equilibrium is extended to flows with wall transpiration. The sink flow TBL is a special case of more
generalised equilibrium TBLs with wall transpiration. Conditions required for the flow with wall transpiration are derived. It is observed that there is a systematic variation of various statistical properties with wall velocity. Further, it is observed that the motion in these equilibrium flows is purely active like in sink flow TBL. In equilibrium TBL, the Reynolds shear stress is directly related to mean velocity. So we have at our disposal an exact relation between the Reynolds shear stress and the mean velocity gradient without the need to do any ad-hoc modelling for the sink flow. This is an interesting observation from the point of view of modelling TBLs using eddy-viscosity. Eddy-viscosity model derived from sink flow TBL data is found to predict the mean velocity profiles in flows with wall transpiration with a sufficient accuracy. Similarly, it is plausible that
any general non-equilibrium flow may be treated as a departure from equilibrium. With
suitable modifications, eddy viscosity obtained from equilibrium TBL may be used to
model them without invoking ad-hoc assumptions.
Finally, the effect of initial Reynolds number on the process of relaminarisation is
studied numerically and experimentally. ZPG TBLs with two different initial Reynolds
number are subjected to different degrees of acceleration. However, the pressure gradient
history is same in both the cases. It is observed that the flow with a higher initial
Reynolds number relaminarises at a lower pressure gradient value than the flow with a
lower initial Reynolds number. Assessment of different parameter criteria reveals that the
criterion proposed by Narasimha & Sreenivasan (1973) is appropriate for the prediction of
the onset of relaminarisation. Further, the structures in relaminarising flows are studied.
The near-wall structure angle is found to decrease with the increasing FPG and the
streamwise length of the structure also increases. The low and high speed streaks in the near-wall region are found to become longer and less undulating with an increase in the spanwise spacing. A stabilisation mechanism of near-wall streaks is also presented which suggests that the kinematic effect of mean vertical velocity directed towards the wall is responsible for the stabilisation of streaks.
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Os reservat?rios eutrofizados da regi?o tropical semi?rida atuam como emissores ou como sequestradores de di?xido de carbono? / Eutrophic semiarid reservoirs: carbon dioxide-sink or carbon dioxide-source systems?Mendon?a J?nior, Jurandir Rodrigues de 31 March 2014 (has links)
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Previous issue date: 2014-03-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The aquatic ecosystems can play a role as carbon-dioxide-source or carbon-dioxide-sink systems due to the high predominance of heterotrophic or autotrophic metabolism. The primary production can strongly affect the carbon balance (CO2) through the consumption of carbon dioxide in the photosynthesis, especially in eutrophic environment, acting as a carbon sink. The present study tested the hypothesis that the eutrophic reservoirs in tropical semi-arid region are carbon dioxide-sink systems due to the high primary productivity presented in these systems. Five Brazilian reservoirs from the semi-arid in the northeast region were monitored monthly during four years (2010 to 2013) with a prolonged drought event identified during the study. The results showed an increasing level of eutrophication over the period of prolonged drought, with the predominance of autotrophy. Significant negative correlations were observed between the partial pressure of CO2 (pCO2) (p<0,001) and chlorophyll-a in the Boqueir?o, Passagem das Tra?ras, Dourado and Gargalheiras reservoirs, showing a pattern of the carbon dioxide-sink systems. However, this pattern was not found in Cruzeta reservoir. In summary, in the tropical semi-arid region, hydrological and morphometric variables can lead to different behaviors of the water-supply reservoirs on the carbon metabolism. The eutrophic reservoirs evaluated showed a negative relationship between pCO2 and Chl-a, which suggests that these water bodies show an autotrophic metabolism and behave as carbon dioxide- sink systems / Os ecossistemas aqu?ticos podem atuar como emissores ou sequestradores de carbono em fun??o da predomin?ncia do metabolismo heterotr?fico ou autotr?fico. A produ??o prim?ria pode afetar fortemente o balan?o de carbono (CO2) atrav?s do consumo de di?xido de carbono na fotoss?ntese, especialmente em ambiente eutr?ficos, atuando como sumidouros. O presente estudo testou a hip?tese de que reservat?rios eutrofizados da regi?o tropical semi?rida s?o sequestradores de CO2 em fun??o da alta produtividade evidenciada nesses sistemas. Cinco reservat?rios da regi?o semi?rida do nordeste do Brasil foram monitorados mensalmente durante o per?odo de 2010 ? 2013, com um evento de seca prolongada identificado durante o estudo. Os resultados mostraram um crescente n?vel de eutrofiza??o ao longo do per?odo de seca prolongada com predomin?ncia de autotrofia. Foram observadas correla??es negativas significativas entre a press?o parcial de CO2 (pCO2) (p<0,001) e clorofila-a nos reservat?rios Boqueir?o, Passagem das Tra?ras, Dourado e Gargalheiras, evidenciando um padr?o de sequestro de CO2 desses sistemas. Por?m, este padr?o n?o foi encontrado no reservat?rio Cruzeta. Em s?ntese, na regi?o semi?rida tropical, as vari?veis hidrol?gicas e morfom?tricas podem direcionar diferentes comportamentos dos reservat?rios de abastecimento no metabolismo do carbono. Os reservat?rios eutrofizados avaliados apresentaram uma rela??o negativa entre pCO2 e Chl-a o que sugere que estes corpos h?dricos evidenciam um metabolismo autotr?fico e se comportam como sequestradores de CO2
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Heurísticas para o problema de cobertura em redes de sensores sem fio hierárquicas com sorvedouro móvelAraújo, André Ricardo Melo 01 March 2013 (has links)
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Previous issue date: 2013-03-01 / FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas / Wireless Sensor Network (WSN) is a special kind of ad hoc networks composed
of devices capable of processing, storing, sensing the environment, and transmitting
data via wireless communication interface. The sensor nodes have several
limitations, among them the capacity of energy because to the reduced size. For
this reason, many searches have been done with a view to improving the energy
consumption of sensor nodes.
This work aims to address the Problem of Coverage, Clustering and Routing
with Mobile Sink (PCAR-SM, in portuguese Problema de Cobertura, Agrupamento
e Roteamento com Sorvedouro Móvel) in WSN with mobile sink consisting
of: given a set of sensor nodes and a monitoring area, develop algorithms to find
the best subset of sensor nodes to cover the monitoring area, group them in a smaller
number of clusters and find the shortest route to mobile sink navigate. The
PCAR-SM is a strategy used to reduce the energy consumption of sensor nodes,
data collisions, interference and redundant data in networks with high concentration
of sensor nodes per area.
The purpose of this paper is to solve each problem separately and together,
in order to evaluate the impact of each problem on the other. The Coverage
Problem has been solved with two metaheuristics: an Genetic Algorithm (GA)
and a Greedy Randomized Adaptive Search Procedure (GRASP) algorithm. In
the latter we used two representations of solution: (a) representation by sensor,
where each element of the solution vector represents a sensor node that must
be switched on or off; (b) representation by demand, where each element of the
solution vector represents a demand point will indicate which sensor node cover
it. The AG uses only the representation by demand. The computational results for Coverage Problem used the benchmark of Beasley s
OR Library and it was possible seen that the GRASP with representation
by demand achieved better results than the GA and the GRASP with representation
by sensor when the optimization criterion is to minimize the total cost of
each sensor node used in the solution.
For Clustering Problem was created approach of virtual grids. In this approach,
we divide the area into grids and clusters are formed by a set of adjacent grids
(maximum 5 grids in group) forming a cross schematic. The aim of the problem
is to minimize the number of clusters in the area.
With this approach, we can model the Clustering Problem as a Set Cover
Problem (SCP) without overlapping (an element does not belong to more than one
set), which was treated by a greedy heuristic called Greedy Clustering Algorithm
(GCA). The virtual grids proved to be a good solution because it is simple to
identify a node which grid it belongs. Its simplicity also makes it a appropriate
method for a distributed version.
The Routing Problem of sink was modeled as the Travelling Salesman
Problem (TSP), where the mobile sink part of a corner of the monitoring area,
runs through the area visiting all clusters and returns to the starting point. For
this, we propose two greedy approaches based on nearest neighbor, the Routing
Greedy Algorithm - Center (RGA-C) and Routing Greedy Algorithm - Border
(RGA-B). The route of the sink was also solved by a heuristic based on algorithm
Centralized Spatial Partitioning (CSP). In CSP approach, the route is fixed and
reminds the movement of a snake. The results show that fixed route produces a
path with smaller size compared to the greedy heuristic for TSP.
We analyze also the PCAR-SM, creating heuristic strategies. The union of
the Clustering Problem and Routing Problem proved more beneficial in relation
to the size of the sink s route. The union of Coverage Problem and Clustering
Problem only proved beneficial when the communication radius was about 3,9
times greater than the sensing radius.
Our results show that solve problems together allows some changes in the
algorithms will lead to better results. / As Redes de Sensores Sem Fio (RSSFs) são um tipo especial de redes ad hoc
constituídas por dispositivos capazes de processar, armazenar, sensoriar o ambiente
e transmitir dados via interface de comunicação sem fio, denominados nós sensores.
Os nós sensores possuem várias limitações, dentre elas, a capacidade de energia
devido ao tamanho reduzido. Por isto, muitas pesquisas foram feitas tendo em
vista a melhoria no consumo de energia dos nós sensores.
Este trabalho tem como objetivo tratar o Problema de Cobertura, Agrupamento
e Roteamento com Sorvedouro Móvel (PCAR-SM) em RSSF com nó
sorvedouro móvel, que consiste em: dado um conjunto de nós sensores e uma área
de monitoramento, desenvolver algoritmos para encontrar o melhor subconjunto
de nós sensores que cubra a área de monitoramento, juntá-los no menor número de
grupos possíveis e encontrar a menor rota para um nó sorvedouro móvel percorrer.
O PCAR-SM é uma estratégia utilizada para diminuir o consumo de energia dos
nós sensores, a colisão de dados, as interferências e os dados redundantes em redes
com alta concentração de nós sensores por área.
A proposta deste trabalho é resolver cada problema separadamente e em
conjunto, de modo a avaliar o impacto de cada problema na solução do outro.
O Problema de Cobertura foi resolvido com duas metaheurísticas: um Algoritmo
Genético (AG) e um algoritmo Greedy Randomized Adaptive Search Procedure
(GRASP). Neste último foram utilizadas duas representações de solução: (a)
representação por sensor, onde cada elemento do vetor de solução representa um
nó sensor que estará ligado ou desligado; (b) representação por demanda, onde cada
elemento do vetor de solução representa um ponto de demanda no qual indicará
qual o nó sensor o cobre. O AG utiliza apenas a representação por demanda. Os resultados computacionais para o Problema de Cobertura utilizaram o
benchmark da Beasley s OR Library e foi possível constatar que o GRASP com
representação por demanda obteve melhores resultados que o AG e o GRASP com
representação por sensor quando o critério de otimização é minimizar a soma total
dos custos de cada nó sensor utilizado na solução.
Para o Problema de Agrupamento foi criada uma abordagem de grades virtuais.
Nesta abordagem dividimos a área em grades e os grupos são formados por
um conjunto de grades adjacentes (no máximo 5 grades) formando um esquema
de cruz. O objetivo do problema é minimizar o número de grupos na área.
A partir desta abordagem, pode-se modelar o Problema de Agrupamento
como um Problema de Cobertura de Conjuntos (PCC) sem sobreposição (um elemento
não pertence a mais de um conjunto), que foi tratada por uma heurística
gulosa denominada Greedy Clustering Algorithm (GCA). Os grades virtuais provou
ser uma boa solução por ser simples para um nó identificar a qual grade ele
pertence. Sua simplicidade ainda o torna uma método adequado para uma versão
distribuída.
O Problema de Roteamento do nó sorvedouro foi modelado como o Problema
do Caixeiro Viajante (PCV), onde o nó sorvedouro móvel parte de um canto da
área de monitoramento, percorre a área visitando todos os grupos e retorna ao
ponto inicial. Para isto, propomos duas abordagens gulosas baseadas no vizinho
mais próximo, o Routing Greedy Algorithm - Center (RGA-C) e o Routing Greedy
Algorithm - Border (RGA-B). A rota do nó sorvedouro também foi resolvida por
uma heurística baseada no algoritmo Centralized Spatial Partitioning (CSP). Na
abordagem CSP, a rota é fixa e lembra o movimento de uma cobra. Os resultados
mostram que a rota fixa gera um percurso com tamanho menor em comparação
com as heurísticas gulosas para o PCV.
Analisamos, ainda, o PCAR-SM, criando estratégias heurísticas. Aunião dos
Problema de Agrupamento e Roteamento, provou ser mais benéfica em relação ao
tamanho da rota do nó sorvedouro, já a união do Problema de Cobertura com o
Problema de Agrupamento só mostrou ser benéfica quando o raio de comunicação
era aproximadamente 3, 9 vezes maior que o raio de sensoriamento.
Nossos resultados, mostram que resolver os problemas em conjunto permite
que algumas mudanças nos algoritmos levem a melhores resultados.
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Tecnologia alternativa para tratamento dos efluentes domésticos da área rural / Alternative technology for treatment of rural areas domestic sewageLess, Diani Fernanda da Silva 14 February 2014 (has links)
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Previous issue date: 2014-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use absence of domestic systems for wastewater treatment promotes the frequent cases of soil and water resources contamination, and contributes to the spread of diseases in the population. Within this context, the work aimed the development/proposition a methodology and alternative technology for treatment domestic sewage of residences located in rural area, specifically for the treatment of effluents generated in the kitchen sink and the toilet bowl. For this, was performed the domestic effluents source characterization through the management diagnostic of domestic wastewater in Paraná state and the city of Toledo; domestic effluents qualitative (physical, chemical and biological parameters) and quantitative (daily and monthly volume) characterization; performance evaluation of the conventional methods, processes and technologies for treatment of rural areas domestic sewage; the method and the technology design/developing for the rural domestic sewage treatment from the toilet bowl and kitchen sink; the construction, operation and monitoring of alternative technology; and the agreement analysis. From the results obtained in the first step, it was found that in Paraná state rural areas are generated over 261 thousand m³ day-1 of domestic sewage, in the city of Toledo rural area are produced 37,410.8 m3 of domestic effluent monthly. In the evaluation step of treatment methods and technologies it was verified the existence of technical limitations and bottlenecks in the equipment, prevailing the low treatment efficiency. Based on detailed studies of the physical, chemical and biological fundamentals and testing bench, was developed the project of alternative technology containing a feces and urine separator; a helical anaerobic bioreactor with tubular shape for the feces. The technology alternative prototype operation showed satisfactory results with respect the feces and urine separation and the feces stabilization in the reactor was completed in just 30 days of treatment forming a residual without the E. coli presence (<1 NMP g-1). / A ausência no uso de sistemas de tratamento de efluentes domésticos na área rural promove frequentes casos de contaminação do solo e dos recursos hídricos, bem como contribui com a disseminação de doenças entre a população. Nesse contexto, o objetivo do trabalho foi o desenvolvimento/proposição de uma tecnologia alternativa para o tratamento dos efluentes gerados no vaso sanitário e na pia da cozinha de residências da área rural. Para isso, realizou-se a caracterização da fonte geradora de efluentes domésticos por meio do diagnóstico da gestão dos efluentes doméstico no estado do Paraná e no município de Toledo; a caracterização quantitativa (volume diário e mensal) e qualitativa (parâmetros físicos, químicos e biológicos) dos efluentes domésticos; a avaliação do desempenho dos métodos, processos e tecnologias convencionais para o tratamento de efluentes domésticos das áreas rurais; o projeto/desenvolvimento do método e da tecnologia alternativa para o tratamento dos efluentes domésticos rurais provenientes do vaso sanitário e da pia da cozinha; a construção, operação e monitoramento da tecnologia alternativa; e a análise de concordância. A partir dos resultados obtidos na primeira etapa, constatou-se que nas áreas rurais do estado do Paraná são gerados mais de 261 mil m³. dia-1 de efluentes domésticos, na área rural da cidade de Toledo são produzidos 37410,8 m3 de esgoto domestico mensalmente. Na etapa de avaliação dos métodos e tecnologias de tratamento, constatou-se a existência de limitações e gargalos técnicos nos equipamentos, prevalecendo à baixa eficiência no tratamento. Com base em estudos detalhados dos fundamentos físicos, químicos e biológicos e dos testes de bancada, foi desenvolvido o projeto da tecnologia alternativa contendo um separador de fezes e urina, um biorreator anaeróbico helicoidal de formato tubular para o tratamento das fezes. A operação do protótipo da tecnologia alternativa apresentou resultados satisfatórios quanto a segregação das fezes e da urina e a estabilização dos dejetos no reator foi completa em apenas 30 dias de tratamento originando um composto sem a presença de E. coli (<1 NMP g-1).
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