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Time history-analyses of building structures have been used for a quite long time for research at universities. Considering the advantage of time-history analysis relative to the equivalent static force method, the National Building of Canada and other modern building codes around the world require the use of time-history analysis in the design of specified types of buildings located in seismic regions. One of the main issues in the use of time-history analysis is related to the selection and scaling of the seismic excitations (i.e., accelerograms) to be compatible with the design spectrum for the location considered. Currently, both recorded (i.e., “real”) accelerograms and artificial accelerograms are used in the analyses. The objective of this study is to determine the effects of the selection and scaling of seismic excitations on the response of reinforced concrete frame buildings. Three reinforced concrete frame buildings with heights of 4 storey, 10 storey and 16 storey, designed for Vancouver (high seismic zone) were used in this study. Five sets of seismic excitations were used in the analysis – one set of “real” accelerograms, and four sets of artificial accelerograms obtained by different methods. All sets were scaled to be compatible with the design spectrum for Vancouver. Both linear and nonlinear time history analyses were conducted on the buildings considered. Interstorey drifts and storey shear forces were used as response parameters. The results from the linear analysis show that both the interstorey drifts and the shear forces are affected significantly by the type of the excitation set. Similarly, the effects of the type of the seismic excitations on the drifts from nonlinear analysis are substantial. On the other hand, the influence of the excitation sets on the storey shears from nonlinear analysis are quite small. Based on the results from this study, sets of scaled real records are preferred for use in time-history analysis of building structures. If such records are not available, then sets of simulated accelerograms based on the regional seismic characteristics should be used.

Establishment of relationships for predicting the lateral drift demands of near-fault ground motions is one of the major challenges in earthquake engineering. Excessive lateral drifts caused by earthquake ground motions are the major causes of structural damage observed in structures. In this study, some of the fundamental characteristics of near-fault ground motions are examined. Response characteristics of elastic frame structures to near-fault ground motions are investigated. An approximate method for estimating the elastic ground story and interstory drifts for regular frame type structures is presented. Inelastic displacement demands imposed on elasto-plastic single degree of freedom (SDOF) systems subjected to near-fault ground are examined. Three equations for estimating the maximum lateral inelastic displacement demand from the maximum elastic displacement demand are established. Two of these equations relate the inelastic and elastic displacement demands through natural period and strength reduction factor. The third equation relates the inelastic and elastic displacement demands through the ratio of natural period to pulse period and the strength reduction factor. Efficiency of the natural period to pulse period ratio for estimating the inelastic displacement ratio is shown. Error statistics of the proposed equations are presented and compared with similar studies in the literature. According to the results, these equations can be used for quick and rough estimates of displacement demands imposed on regular elastic moment resisting frames and elasto-plastic single degree of systems.

The construction of reinforced concrete buildings with unreinforced infill is common practice even in seismically active country such as Bhutan, which is located in high seismic region of Eastern Himalaya. All buildings constructed prior 1998 were constructed without seismic provisions while those constructed after this period adopted seismic codes of neighbouring country, India. However, the codes have limited information on the design of infilled structures besides having differences in architectural requirements which may compound the structural problems. Although the influence of infill on the reinforced concrete framed structures is known, the present seismic codes do not consider it due to the lack of sufficient information. Time history analyses were performed to study the influence of infill on the performance of concrete framed structures. Important parameters were considered and the results presented in a manner that can be used by practitioners. The results show that the influence of infill on the structural performance is significant. The structural responses such as fundamental period, roof displacement, inter-storey drift ratio, stresses in infill wall and structural member forces of beams and column generally reduce, with incorporation of infill wall. The structures designed and constructed with or without seismic provision perform in a similar manner if the infills of high strength are used.

Intressenter grundar många av sina investeringsbeslut på vad som presenteras i bolags finansiella rapporter. Revisorer har därmed en viktig roll i samhället eftersom deras uppgift är att bestyrka finansiella rapporter och säkerställa att de i all väsentlighet ger en rättvisande bild av bolaget. För att revisorers arbete ska kunna ses som tillförlitligt krävs det att de producerar revision av hög kvalitet, vilket kräver att de är opartiska, har rätt kompetens och följer de riktlinjer och standarder som finns. Ett vanligt sätt att mäta revisionskvalitet är genom antalet fortsatt drift-kommentarer som utfärdats i revisionsberättelsen hos konkursdrabbade bolag. Att bristande revisionskvalitet har en negativ inverkan på samhället visades tydligt efter de uppmärksammade revisionsskandaler som inträffade under början av 2000-talet. Till följd av detta blev revisionskvaliteten starkt ifrågasatt, diskussioner och arbete för att höja revisionskvaliteten påbörjades. Forskning fokuserade mycket på att finna vilka faktorer som påverkar revisionskvaliteten. Dessa visade varierade resultat och det har även efterfrågats forskning med fokus på hur en revisors egenskaper kan påverka revisionskvaliteten. Det ger tydliga indikationer till att mer forskning gällande revisorers egenskaper behövs. Syftet med studien var att genom fortsatt drift-kommentarer uppskatta revisionskvalitet för att se om det skett en förbättring mellan åren 2012–2017. Syftet var också att undersöka hur en revisors kön, erfarenhet, ålder och storleken på staden revisorn arbetar i påverkar revisionskvaliteten. Studien genomfördes med en kvantitativ metod där ett urval på 1871 på bolag gjordes. De bolag som inkluderades i urvalet var svenska aktiebolag som har inlett en konkurs mellan 2012-01-01 och 2018-03-16. Det krävdes att konkursen var inledd inom loppet av tolv månader från det senaste bokslutsåret och att bolaget har haft en årsredovisning med en revisionsberättelse tillgänglig. Resultatet visar att det skett en procentuell förbättring av revisionskvalitet mellan år 2012 och 2017. Dock har det endast skett en signifikant förbättring från år 2012 fram till 2014. Resultatet visar även att det finns ett negativt samband mellan revisionskvalitet och en revisors ålder respektive erfarenhet. Sambandet innebär att yngre och mindre erfarna revisorer håller högre revisionskvalitet jämfört med äldre och mer erfarna revisorer. Studien visar att det inte förekommer något samband mellan en revisors kön och revisionskvalitet. Det identifierades endast ett svagt samband mellan stadsstorleken på staden som revisorn arbetar i och revisionskvalitet. Dock finns indikationer att revisorer som arbetar i storstäder håller högre revisionskvalitet.

abstract: ABSTRACT This study investigated the possibility of item parameter drift (IPD) in a calculus placement examination administered to approximately 3,000 students at a large university in the United States. A single form of the exam was administered continuously for a period of two years, possibly allowing later examinees to have prior knowledge of specific items on the exam. An analysis of IPD was conducted to explore evidence of possible item exposure. Two assumptions concerning items exposure were made: 1) item recall and item exposure are positively correlated, and 2) item exposure results in the items becoming easier over time. Special consideration was given to two contextual item characteristics: 1) item location within the test, specifically items at the beginning and end of the exam, and 2) the use of an associated diagram. The hypotheses stated that these item characteristics would make the items easier to recall and, therefore, more likely to be exposed, resulting in item drift. BILOG-MG 3 was used to calibrate the items and assess for IPD. No evidence was found to support the hypotheses that the items located at the beginning of the test or with an associated diagram drifted as a result of item exposure. Three items among the last ten on the exam drifted significantly and became easier, consistent with item exposure. However, in this study, the possible effects of item exposure could not be separated from the effects of other potential factors such as speededness, curriculum changes, better test preparation on the part of subsequent examinees, or guessing. / Dissertation/Thesis / M.A. Educational Psychology 2012

Comprendre le transport des pesticides est crucial pour évaluer leur impact écologique. Les connaissances sur la variabilité spatiale des dépôts de pesticides, l'impact de l'érosion sur leur export et leur dégradation in situ restent très limitées à l'échelle des bassins versants. La caractérisation expérimentale et la modélisation ont donc été combinées à deux échelles, parcelle et bassin versant, dans deux contextes agricoles. Un formalisme a été développé pour prédire le transport des pesticides par ruissellement et a été intégré dans le modèle LISEM (LImbourg Soil Erosion Model). Les résultats montrent que les surfaces imperméables contribuent significativement à la masse exportée par ruissellement du vignoble. La partition des pesticides entre phase dissoute et particulaire diffère considérablement selon les molécules et le forçage hydrologique, et la présence de produits de dégradation et un enrichissement en R-métolachlore ont été observés ce qui souligne le potentiel des analyses énantiomériques pour évaluer la biodégradation des pesticides. Globalement, cette étude a démontré que la combinaison des échelles et des approches permet une meilleure compréhension du transport des pesticides. / Understanding pesticide transport is crucial to evaluate their ecological impact on ecosystems. Current knowledge on the spatial variability of pesticide deposition, the impact of erosion on pesticides export and the in situ pesticide degradation is very limited at the catchment scale. In this thesis, characterisation and modeling at two scales, the plot and catchment, were combined in two agricultural contexts. A formalism was developed to predict pesticide transport in runoff and was integrated in LISEM (LImbourg Soil Erosion Model). The results show that impermeable roads contributed to more than 40% to the overall load of fungicides exported via runoff from the vineyard. Pesticide partitioning between suspended solids and runoff water differed largely according to the molecules and the hydrological dynamics. The occurrence of degradation products and the enrichment of one enantiomer were observed suggesting the potential of chiral analyses for assessing biodegradation of chiral pesticides at such scale. Overall, the investigation demonstrated that combining different approaches enable a better understanding of pesticide transport.

La localisation d’un véhicule via les techniques de SLAM (Simultaneous Localization And Mapping pour cartographie et localisation simultanées) a connu un essor important durant les 20 dernières années. Pourtant, peu d’approches ont tenté d’étendre ces algorithmes à une flotte de véhicules malgré les nombreuses applications potentielles. C’est ici l’objectif de cette thèse. Pour ce faire, une approche de SLAM monoculaire pour un seul véhicule a d’abord été développée. Celle-ci propose de coupler un filtre de Kalman étendu avec une représentation cartésienne des amers afin de produire des cartes de faible densité mais de qualité. En effet, l’extension à plusieurs véhicules nécessite des échanges permanents par l’intermédiaire de communications sans fil. Avec peu d’amers dans les cartes, notre approche s’accommode bien du nombre de véhicules de la flotte. Des capteurs peu onéreux ont aussi été privilégiés (une unique caméra et un odomètre) afin de réduire le coût d’une extension multivéhicule. Des correctifs ont été proposés afin d’éviter les problèmes de divergence induits par les choix précédents. Des expérimentations ont montré que la solution de SLAM produite était légère et rapide tout en fournissant une localisation de qualité. La dérive, inhérente à tout algorithme de SLAM, a également fait l’objet d’une analyse. Celle-ci a été intégrée au SLAM par l’intermédiaire d’une architecture dédiée et d’un modèle dynamique. Le but est de pouvoir rendre consistante la localisation fournie par le SLAM, même en l’absence d’estimation de la dérive. Cela permet d’effectuer des fermetures de boucle ou encore d’intégrer des informations géo-référencées de manière naturelle tout en conservant l’intégrité de la solution. En multivéhicule, cet aspect est un point clef puisque chaque véhicule dérive différemment des autres. Il est donc important de le prendre en compte. Enfin, le SLAM a été étendu à plusieurs véhicules. Une structure générique a été prévue afin que notre approche monoculaire puisse être remplacée par n’importe quel algorithme de SLAM. Notre architecture décentralisée évite la consanguinité des données (le fait de compter deux fois une même information) et gère les défaillances réseau, que cela soit des ruptures de communication ou encore des latences dans la réception des données. La partie statique du modèle de dérive permet également de prendre en compte le fait que les positions initiales des véhicules d’une flotte puissent être inconnues. L’intégrité est ainsi maintenue en permanence. Enfin, notre approche étant entièrement décentralisée, elle a pu être testée et validée en simulation et avec des expérimentations réelles dans diverses configurations (convoi en colonne ou en ligne, avec 2 ou 3 véhicules). / The localization of a vehicle with the use of SLAM techniques (Simultaneous Localization And Mapping) has been extensively studied during the last 20 years. However, only a few approaches have tried to extend these algorithms to a fleet of vehicles despite the many potential applications. It is the objective of this thesis. First of all, a monocular SLAM for a single vehicle has been developed. This one proposes to pair an Extended Kalman Filter with a Cartesian representation for landmarks so as to produce accurate low density maps. Indeed, the extension of SLAM to several vehicles requires permanent communications inside the fleet. With only a few landmarks mapped, our approach scales nicely with the number of vehicles. Cheap sensors have been favored (a single camera and an odometer) in order to spread more easily the use of multi-vehicle applications. Correctives have been proposed in order to avoid the divergence problems induced by such a scheme. The experiments showed that our SLAM is able to furnish good localization results while being light and fast.The drift affecting every SLAM algorithm has also been studied. Its integration inside the SLAM process, thanks to a dedicated architecture and a dynamic model, allows to ensure consistency even without an estimation of it. Loop closures or the integration of geo-referenced information becomes straightforward. They naturally correct all the past positions while still maintaining consistency. In a multi-vehicle scenario, it is a key aspect as each vehicle drifts differently from one another. It is consequently important to take it into account. Our SLAM algorithm has then been extended to several vehicles. A generic structure has been used so as to allow any SLAM algorithm to replace our monocular SLAM. The multi-vehicle architecture avoids data incest (double-counting information) and handles network failures, be they communication breakdowns or latencies when receiving data. The static part of the drift model allows to take into account the fact that the initial positions of the different vehicles composing the fleet might be unknown. Consistency is thus permanently preserved. Our approach has been successfully tested using simulations and real experiments with various settings (row or column convoy with 2 or 3 vehicles) in a fully decentralized way.

Bullhead is common fish of our trout zones of streams and small rivers. It lives in mountain streams or small rivers. It needs clear water with high oxygen saturation. Therefor bullhead is used as a bioindicatorof clear waters. The aim of our experiment was compare the influence of artificial and natural flood on bullhead population in river Labe. Artificial flood was caused by wild water race competition in 2011. There was drained the water reservoir Labská during this event. The observed stretch of river Labe was fished out before and after this competition using electric generator. The fish obtained before the artificial flood were branded and released back to the river. New out fishing was done immediately after the flood. There were counted and measured the fish with or without brands. The same manner was used for obtaining of dates before and after natural flood in 2012. The main result of this experiment is showing the artificial flood is more destructive and dangerous than natural flood. The reason is faster increase and decrease of flow in river during the artificial flood.

La dérive de pulvérisation peut être mesurée au champ ou en soufflerie. Paradoxalement, les tests au champ sont sujets à de grandes variations dues aux conditions atmosphériques mais peuvent être plus facilement réalisés contrairement aux tests en soufflerie. Ainsi les principaux modèles de dérive sont basés sur des mesures au champ alors que peu de modèles s’inspirent de mesures en soufflerie. L’objectif de ce travail a été de définir un ou des descripteurs de la dérive sur la base de l’analyse de courbes de dépôts obtenues dans la soufflerie d’IRSTEA Montpellier. Par rapport aux souffleries existantes, un protocole d’exposition de longue durée a été utilisé avec une forte densité d’échantillonnage. Un plan expérimental comprenant 99 modalités a été réalisé en tenant compte de différents types de buses (FF, AI, AI Twin jet), différente hauteurs de rampe de 40 à 80cm, différentes positions de la rampe (frontale, latérale et angles intermédiaires) et différentes vitesses de vent entre 2 et 7.5m s-1. Les résultats ont montré que le taux de dérive à 5m sous le vent (DR5) correspond au descripteur le plus robuste si l’on tient compte du large spectre de paramètres et de réglages. Des modèles de premier ordre ont été définis pour l’expression de l’effet de la vitesse du vent ainsi que de la hauteur de rampe selon le temps de vol des gouttes (ToF). Ainsi il est possible de comparer des résultats issus de conditions expérimentales différentes et de simuler l’effet de la vitesse du vent et la hauteur de la rampe pour un type donné de buse. Des mesures in situ de taille de gouttes ont confirmé la pertinence du temps de vol comme base de l’expression des résultats. / Spray drift might be measured either infield or in a wind tunnel through specific sampling strategies. Paradoxically field tests are subjected to a high variability due to the atmospheric conditions but can be more easily conducted in the absence of a wind tunnel. The result is that most of spray drift models are based on infield measurements. Conversely very few models were developed on the basis of wind tunnel measurements. The objective of this work was to define spray drift descriptors from the analysis of drift curves in IRSTEA wind tunnel. Compared to the majority of existing wind tunnels, a long duration exposure protocol was applied with a high sampling density. A large experimental plan of 99 modalities were conducted including nozzle types (FF, AI, AI Twin jet), boom heights from 40 to 80cm, boom positions (frontal, lateral, and intermediate angles) and wind velocities from 2 to 7.5ms-1. Results showed that the drift ratio at 5m (DR5) was the most robust drift indicator considering the wide range of parameters and operations conditions (wind velocity, boom height). First order models were drawn for the expression of the effect of the wind velocity and the boom height according to the droplet time of flight (ToF). As a result it was possible to compare data from different experimental conditions and to simulate the effect of the wind velocity and the boom height for a given type of nozzle. In situ droplet size measurements confirmed the relevance of the time of flight expression.