Wireless local area networks (WLANs) and wireless sensor networks (WSNs) technologies have been comprehensively developed and deployed during recent years. Since commercial WLAN and WSN products share the same free of license frequency band, the low power, low rate ZigBee based WSNs are vulnerable to the interference from Wi-Fi WLANs. Therefore, it is important to evaluate the performance of ZigBee WSNs that are subjected to interference generated by collocated Wi-Fi WLANs and to design effective counter-measuring techniques should performance improvement is needed. In this research, a versatile testbed for conducting various experiments is established and the ZigBee system’s performance with different clear channel assessment (CCA) modes and energy detection (ED) thresholds are evaluated through extensive experimental measurements in the testbed. It can be concluded from the results that CCA has significant impact on ZigBee’s performance. An existing theoretical analysis approach that is based on the collision time model between ZigBee and Wi-Fi packets is suitably modified to provide analytical evaluation means of the cases we examined. In order to mitigate the interference from the collocated Wi-Fi system, a novel and effective interference-aware adaptive CCA (IAACCA) scheme is proposed and implemented as firmware flashed into Crossbow motes. Experiments confirmed the ability of IAACCA to countermeasure effectively interference generated by Wi-Fi and thus improve the performance of ZigBee WSNs. Finally, a thorough statistical analysis is performed to understand the factors impacting the performance of ZigBee system and is used to further verify our experimental methods.

No description available.

Land use affects the water quality of lakes. Different land use types yield different effects due to varying amounts and constituents of runoff. In this study, the effects of surrounding land use on the water quality of 50 lakes in Seminole County, Florida was assessed. Using GIS, I placed buffers of 100 and 500 m around each lake. The percentages of land use type were calculated within these buffers for 1990 and 1995. An ordination of lakes was done using Canonical Correspondence Analysis (CCA) to determine if the surrounding land use patterns were adequate to describe the trophic status of the lakes. Correlations between land use and water quality were found to be significant for the 1990 100 and 500 m buffers. Inter-set correlations showed that among land use types: residential, urban, agriculture, hardwoods, and wetlands were the most influential in determining water quality in that they had the most positive or negative correlation with the WA scores depending on the year and buffer zone. Excessively drained and very poorly drained soils were the most influential of the soil types. A Discriminant Function Analysis (DFA) was also performed to determine which land use and soil variables were effective in discriminating between oligotrophic, mesotrophic, and eutrophic lakes. Wetlands and very poorly drained soil were the most effective in discriminating between the groups of lakes. A multiple regression analysis was performed that determined correlations for 1990 and change in land use 100 m buffers contributed to our understanding of the relationship between land use and water quality. Effects of land use on water quality need to be considered when attempting to restore a lake or subjecting it to future land development.

Le but de ce travail est d'amorcer une réflexion sur l'architecture, la pratique architecturale en tant que système signifiant, à travers lequel sont représentées des idées, des volontés, des philosophies. En fait, il s'agit de montrer que l'architecture est un outil de communication visuelle, un texte construit à travers lequel il est possible de produire un discours qui nous permet d'accéder à une réalité qui est le reflet de la société qui la produit. L'architecture est ici considérée non pas simplement en tant que forme bâtie, construite, non pas simplement comme un résultat, mais plutôt comme un processus intellectuel qui part d'un concept -le côté virtuel de l'objet, l'idée - et qui peut donner lieu à un objet réel, construit - le côté concret, matériel de l'objet -. Ce processus intellectuel permet d'établir le rapport entre les idées, l'intention du concepteur et le produit fini, soit la forme architecturale. La première partie de ce travail expose les éléments qui ont alimenté cette réflexion. Les travaux de Roland Barthes nous ont permis d'identifier un système connoté - sous-jacent - à partir d'un texte ou système dénoté. L'approche d'Aldo Rossi permèt de voir et comprendre la ville à partir d'éléments structurants qui sont en relation et par lesquels la ville évolue et se transforme; enfin, le travail de Louis Marin sur l'utopie, l'espace du neutre, permet de faire le lien entre un texte écrit et un texte construit. La seconde partie est une validation des mécanismes identifiés dans la première partie sur un objet réel coristruit, le Jardin du Centre Canadien d'Architecture de Montréal. L'analyse nous montrera que l'architecture est représentation. Elle est en fait la représentation d'idées, de savoirs, par ses formes qui agissent comme signes, en inter-relation, référant à une mémoire collective et se traduisant comme un énoncé construit dans et par son contexte de production. Il apparaît clairement que l'architecture appartient d'abord au monde des idées, de la philosophie, où se positionnent des mécanismes intellectuels et conceptuels qui permettent de construire des schèmes - ou figures - d'organisation dont la forme bâtie est la transposition dans le monde réel. Le tout est précédé d'une introduction qui situe le contexte de cette réflexion et dans laquelle est exposé le débat qui existe actuellement entre la modernité et le post-modernisme.

<p>Canonical Correlation Analysis (CCA) is one of the multivariate statistical methods that can be used to find relationship between two sets of variables. I highlighted challenges in analyzing high-dimensional data with CCA. Recently, Sparse CCA (SCCA) methods have been proposed to identify sparse linear combinations of two sets of variables with maximal correlation in the context of high-dimensional data. In my thesis, I compared three different SCCA approaches. I evaluated the three approaches as well as the classical CCA on simulated datasets and illustrated the methods with publicly available genomic and proteomic datasets.</p> / Master of Science (MSc)

This research is motivated by an issue frequently encountered in water quality monitoring and ecological assessment. One concern for researchers and watershed resource managers is how the biological community in a watershed is affected by human activities. The conventional single model approach based on regression and logistic regression usually fails to adequately model the relationship between biological responses and environmental stressors since the study samples are collected over a large spatial region and the response-stressor relationships are usually weak in this situation. In this dissertation, we propose two alternative modeling approaches to partition the whole region of study into disjoint subregions and model the response-stressor relationships within subregions simultaneously. In our examples, these modeling approaches found stronger relationships within subregions and should help the resource managers improve impairment assessment and decision making. The first approach is an adjusted Bayesian classification and regression tree (ABCART). It is based on the Bayesian classification and regression tree approach (BCART) and is modified to accommodate spatial partitions in ecological studies. The second approach is a Voronoi diagram based partition approach. This approach uses the Voronoi diagram technique to randomly partition the whole region into subregions with predetermined minimum sample size. The optimal partition/cluster is selected by Monte Carlo simulation. We propose several model selection criteria for optimal partitioning and modeling according to the nature of the study and extend it to multivariate analysis to find the underlying structure of response-stressor relationships. We also propose a multivariate hotspot detection approach (MHDM) to find the region where the response-stressor relationship is the strongest according to an R-square-like criterion. Several sets of ecological data are studied in this dissertation to illustrate the implementation of the above partition modeling approaches. The findings from these studies are consistent with other studies. / Ph. D.

The amount of CCA treated wood being removed from spent residential decks is increasing at a tremendous rate. While most spent CCA treated wood is being disposed in landfills, further useful and environmentally beneficial alternatives have to be met. This research estimated the percentage of recoverable lumber from spent CCA decks that can be recycled into other usable products. Six residential decks were removed from service, by either demolition or deconstruction procedures. It was found that 86% of the CCA treated wood from the residential decks could be recovered as reusable CCA treated lumber. It was also found that deconstruction of a residential deck, rather than demolition, was not a factor in the volume of CCA treated wood recovered. Chemical and mechanical properties of the removed CCA treated wood were also analyzed. The chemical retention of the deck material proved that most of the spent CCA treated wood could be used in above ground applications. The stiffness of spent CCA treated wood from residential decks was approximately equal to that of recently treated CCA wood. The strength properties were slightly lower than recently treated CCA wood probably due mainly to physical and climatic degradation. Products were then produced that could be successfully utilized by recycling centers or community and government organizations. Products manufactured included, pallets, picnic tables, outdoor furniture, residential decks, and landscaping components. Waste management, recycling, and government organizations were interviewed to determine what markets and barriers exist for recycled CCA treated products. Most landfill and recycling facilities do not currently sort or recycle CCA treated wood, citing the main reason as a lack of a viable market. Potential users were interested in the material but citied they did not know where to locate the material. A communication barrier exists between the waste management industry, recyclers, and users; which is preventing the successful recycling of CCA treated wood from spent residential decks. / Master of Science

Les sols sous contraintes que ce soit du point de vue charges polluantes comme avec les Métaux Traces (MT) ou bien du point de vue stress hydrique (perte des capacités de rétention menant à la désertification des sols) concernent de nombreux espaces du territoire national, de même que la région du pourtour Méditerranéen. Le nombre de sites pollués par des substances inorganiques affectant de larges espaces est en constante augmentation. Les stratégies pour leur rémédiation sont variées mais très peu envisagent la dépollution tout en restaurant les propriétés pédologiques des sols concernés. La rémédiation comme la restauration des capacités fertilisantes de sols pollués sont un enjeu international. Pour cela, la stratégie de cette étude porte sur le développement d’outils technologiques innovants basée sur la phytorémédiation assistée par des matrices duales de sols contaminés par des MT (Cuivre, Chrome, Arsenic). Ces matrices duales ont une action double concomitante en permettant une immobilisation ou un piégeage des MT tout en favorisant la repousse végétale ou la catalyse de la croissance végétale. Le piégeage peut se faire par l’apport d’amendement ayant des capacités d’échanges (généralement liées à l’existence de phase allophane et/ou d’un réseau poral important) et de rétention (liées au réseau porale et à l’existence de phases minérales type phosphates, silice amorphe, oxydes hydroxydes de fer-manganèse). L’élaboration, à partir de laitiers d’aciéries, d’une matrice susceptible d’adsorber des MT (aspect dépollution) tout en favorisant la pousse végétale (aspect amendement) nous a permis de tester ce produit de synthèse. La seconde originalité de cette étude est d’analyser le potentiel de ces matrices, non seulement à différentes échelles (du pot en passant par le stade mésocosme et jusqu’au champ), du point de vue impact écotoxique – dépollution de sols associé à une re-végétalisation. Cette dernière participe également au transfert des charges polluantes (MT) depuis l’amendement de synthèse ou du sol vers, et dans le réseau racinaire des radicelles et ainsi favoriser la réhabilitation des propriétés hydriques des sols par le développement d’un couvert végétale pérenne. On conjugue ainsi un apport dépolluant à celui de maintient de la potentielle anti-désertification grâce au développement de solutions innovantes respectueuses de l’environnement sur la base de technologie douce valorisant les co produits de l’industrie. / Soil contamination by trace elements is a widespread problem in many parts of the world. The accumulation of toxic metals in soil is mainly inherited from parent materials or inputs through human activities. In fact, one of the sources of soil contaminations is very important resulting from chemical widely used wood preservative industries in aquatic environments and storing the wood after treatment by chromated copper arsenate (CCA). Elements such as As, Cu, Cr, and Zn can be found in excess in contaminated soils at wood treatment facilities, especially when Cu sulphates and chromated copper arsenate (CCA) were used as a preservative against insects and fungi, which may result in soil phytotoxicity as well as toxic to plants, animals and humans. New techniques are being developed to remediate trace elements in contaminated soils such as phytoremediation and in situ stabilization. In situ stabilization technique or in situ immobilisation is one of the common practices for reducing negative effects of metals and metalloids such as As, Cr, Cu, Pb, Cd and Zn in contaminated soils by adding amendments. Alkaline materials are usually added to acidic soils to improve soil chemical and physical properties and also to reduce the mobility and bioavailability of contaminant. Slag, which consists of calcium oxide, phosphorus oxide, silicon oxide, iron oxide, and other metal oxides, is an alkaline by-product of metallurgical processes or a residue of incineration processes. Slags have been successfully used to soil reclamation and soil fertiliser. It has been used as a soil additive to reduce various metals contaminated soil by precipitation and adsorption on the surface of metal oxide. The objectives of this Ph.D study were to evaluate the physical, chemical soil properties and the distribution of trace elements in contaminated soil. Also to evaluate the characteristics of two different slags samples, a basic slag (BS) and a basic slag phosphate (BSP) which are alkaline by-products of the French steel industry and which used as a soil amendments to improve soil properties and for the in situ immobilisation of copper and metals in chromated copper arsenate (CCA) contaminated soil.

A preservação química visa proteger a madeira contra quaisquer ações deterioradoras, sejam elas consequências de fenômenos físico-químicos, como a ação do intemperismo, ou de fenômenos biológicos, como os organismos xilófagos. No Brasil, os preservativos mais utilizados nas usinas de preservação são o Arseniato de Cobre Cromatado (CCA) e o Borato de Cobre Cromatado (CCB). Ambos são aplicados na madeira através do processo de vácuo-pressão, método que em tese poderia aumentar a quantidade de defeitos superficiais e diminuir os valores das propriedades físico-mecânicas das madeiras. Atualmente, em decorrência da disponibilização no mercado (devida à implantação de áreas certificadas no Brasil) de espécies de madeira de média a baixa densidade, a questão da necessidade da preservação contra a demanda biológica se constitui em aspecto de fundamental importância para que se garantam as alternativas de oferta desse material para a construção de estruturas, cuja durabilidade seja equivalente à da madeira de espécies de uso consagrado, como Jatobá, Sucupira, Garapa e Itaúba, por exemplo. Neste contexto, o presente trabalho teve como objetivo investigar a influência dos tratamentos com os preservativos CCA e CCB nas propriedades físico-mecânicas das seguintes espécies de madeiras tropicais brasileiras: Simarouba amara (C20), Cedrelinga catenaeformis (C30) e Erisma uncinatum Warm (C40), escolhidas na tentativa de abranger as três classes de resistência mais baixas, de acordo com o que prescreve a ABNT NBR 7190:1997. Foi realizada a caracterização completa de cada espécie nos três tipos de tratamento (Sem tratamento &#8211; Ref; CCA; CCB) para posterior aplicação do teste de comparações múltiplas de Tukey, avaliado ao nível de 5% de significância. Para avaliar o comportamento dos preservativos a nível celular, foram geradas fotomicrografias por Microscopia Eletrônica de Varredura (MEV) e seus respectivos espectros de EDS. Os resultados obtidos mostraram que ambos os tratamentos químicos não afetaram significativamente os valores das propriedades físico-mecânicas das espécies estudadas. / The chemical preservation aims to protect the wood against any deteriorating actions, be they consequences of physical-chemical phenomena, such as weathering, or biological phenomena, such as xylophagous organisms. In Brazil, the most used preservatives in the preservation plants are Chromated Copper Arsenate (CCA) and Chromated Copper Borate (CCB). Both are applied to the wood through the vacuum-pressure process, which in theory could increase the amount of surface defects and decrease the values of the physical-mechanical properties of the wood. Currently, due to the availability in the market (due to the implantation of certified areas in Brazil) of medium to low density wood species, the question of the need for preservation against biological demand is an aspect of fundamental importance to ensure the alternatives of supply of this material for the construction of structures, whose durability is equivalent to the wood of species of consecrated use, such as Jatobá, Sucupira, Garapa and Itaúba, for example In this context, the present work had as objective to investigate the influence of the treatments with the preservatives CCA and CCB on physical-mechanical properties of the following species of Brazilian tropical woods: Simarouba amara (C20), Cedrelinga catenaeformis (C30) e Erisma uncinatum Warm (C40), chosen in an attempt to cover the three lower resistance classes, according to what ABNT NBR 7190:1997 prescribes. The complete characterization of each species in the three types of treatments (No treatment - Ref: CCA; CCB) was performed for the subsequent application of the Tukey\'s multiple comparison test, evaluated at the 5% level of significance. To evaluate the behavior of the preservatives at the cellular level, photomicrographs were generated by Scanning Electron Microscopy (SEM) and their respective EDS spectra. The results obtained showed that both chemical treatments did not affect significantly the values of the physical-mechanical properties of the studied species.

A preservação química visa proteger a madeira contra quaisquer ações deterioradoras, sejam elas consequências de fenômenos físico-químicos, como a ação do intemperismo, ou de fenômenos biológicos, como os organismos xilófagos. No Brasil, os preservativos mais utilizados nas usinas de preservação são o Arseniato de Cobre Cromatado (CCA) e o Borato de Cobre Cromatado (CCB). Ambos são aplicados na madeira através do processo de vácuo-pressão, método que em tese poderia aumentar a quantidade de defeitos superficiais e diminuir os valores das propriedades físico-mecânicas das madeiras. Atualmente, em decorrência da disponibilização no mercado (devida à implantação de áreas certificadas no Brasil) de espécies de madeira de média a baixa densidade, a questão da necessidade da preservação contra a demanda biológica se constitui em aspecto de fundamental importância para que se garantam as alternativas de oferta desse material para a construção de estruturas, cuja durabilidade seja equivalente à da madeira de espécies de uso consagrado, como Jatobá, Sucupira, Garapa e Itaúba, por exemplo. Neste contexto, o presente trabalho teve como objetivo investigar a influência dos tratamentos com os preservativos CCA e CCB nas propriedades físico-mecânicas das seguintes espécies de madeiras tropicais brasileiras: Simarouba amara (C20), Cedrelinga catenaeformis (C30) e Erisma uncinatum Warm (C40), escolhidas na tentativa de abranger as três classes de resistência mais baixas, de acordo com o que prescreve a ABNT NBR 7190:1997. Foi realizada a caracterização completa de cada espécie nos três tipos de tratamento (Sem tratamento &#8211; Ref; CCA; CCB) para posterior aplicação do teste de comparações múltiplas de Tukey, avaliado ao nível de 5% de significância. Para avaliar o comportamento dos preservativos a nível celular, foram geradas fotomicrografias por Microscopia Eletrônica de Varredura (MEV) e seus respectivos espectros de EDS. Os resultados obtidos mostraram que ambos os tratamentos químicos não afetaram significativamente os valores das propriedades físico-mecânicas das espécies estudadas. / The chemical preservation aims to protect the wood against any deteriorating actions, be they consequences of physical-chemical phenomena, such as weathering, or biological phenomena, such as xylophagous organisms. In Brazil, the most used preservatives in the preservation plants are Chromated Copper Arsenate (CCA) and Chromated Copper Borate (CCB). Both are applied to the wood through the vacuum-pressure process, which in theory could increase the amount of surface defects and decrease the values of the physical-mechanical properties of the wood. Currently, due to the availability in the market (due to the implantation of certified areas in Brazil) of medium to low density wood species, the question of the need for preservation against biological demand is an aspect of fundamental importance to ensure the alternatives of supply of this material for the construction of structures, whose durability is equivalent to the wood of species of consecrated use, such as Jatobá, Sucupira, Garapa and Itaúba, for example In this context, the present work had as objective to investigate the influence of the treatments with the preservatives CCA and CCB on physical-mechanical properties of the following species of Brazilian tropical woods: Simarouba amara (C20), Cedrelinga catenaeformis (C30) e Erisma uncinatum Warm (C40), chosen in an attempt to cover the three lower resistance classes, according to what ABNT NBR 7190:1997 prescribes. The complete characterization of each species in the three types of treatments (No treatment - Ref: CCA; CCB) was performed for the subsequent application of the Tukey\'s multiple comparison test, evaluated at the 5% level of significance. To evaluate the behavior of the preservatives at the cellular level, photomicrographs were generated by Scanning Electron Microscopy (SEM) and their respective EDS spectra. The results obtained showed that both chemical treatments did not affect significantly the values of the physical-mechanical properties of the studied species.