Dissertations / Theses on the topic 'Panels – Tests – Analyse'

Les concentrateurs photovoltaïques sont parmi les technologies d'énergies solaires les plus prometteuses. Ils ont une efficacité allant jusqu'à deux fois celle des panneaux photovoltaïques conventionnels. Malgré les avancements en recherche et développement, les concentrateurs photovoltaïques demeurent des systèmes relativement complexes. Cette même complexité laisse place à l'innovation et à la possibilité de réduire considérablement les coûts de fabrication. Dans le cadre de cette thèse, deux sites de tests sont développés et déployés pour faire l'analyse des performances des concentrateurs photovoltaïques plats. Quatre designs de cellules solaires sont caractérisés en laboratoire et incorporés dans les panneaux prototypes pour ensuite être individuellement étudiés. Les quatre designs sont ensuite comparés l'un à l'autre, et selon leurs emplacements, pour comprendre comment le design de la cellule affecte la performance des panneaux.

Le nombre de sujets du panel détermine en grande partie le coût des études descriptives et hédoniques de l'analyse sensorielle. Une fois les risques α et β fixés, ce nombre peut théoriquement être calculé, dés lors que l'on connait la variabilité de la mesure due à l'hétérogénéité de la population visée et que l'on fixe la taille de la différence que l'on désire mettre en évidence. En général, l'ordre de grandeur du premier de ces paramètres est inconnu alors que celui du second est délicat à préciser pour l'expérimentateur. Ce travail propose une documentation systématique des valeurs prises dans la réalité par ces deux paramètres grâce à l'exploitation de deux bases de données, SensoBase et PrefBase, contenant respectivement un millier de jeux de données descriptives et quelques centaines de jeux de données hédoniques. Pratiquement, des recommandations pour la taille de panel sont établies sous forme d'abaques prenant en compte trois niveaux pour chacun des deux risques et des deux paramètres.D'autre part, ce travail étudie le nombre de sujets dans chacun des deux types de panel par une approche de ré-échantillonnage qui consiste à réduire progressivement le nombre de sujets tant que les résultats de l'analyse statistique demeurent stables. En moyenne, la taille des panels descriptifs pourrait être réduite d'un quart du nombre de sujets, mais cette moyenne cache une forte hétérogénéité selon le type de descripteurs considéré. La taille optimale des panels hédoniques serait elle très variable et cette variabilité est induite beaucoup plus par la nature et l'importance des différences entre les produits que par l'hétérogénéité des préférences individuelles. De plus, une même approche de ré-échantillonnage appliquée aux répétitions en tests descriptifs suggère que les répétitions ne sont plus nécessaires en phase de mesure, c'est-à-dire une fois le panel entraîné

Notre travail a porté sur la caractérisation instrumentale et sensorielle de la texture d'une gamme de produits modèles de types fromages fondus. Trois objectifs ont guidé cette thèse. Le premier objectif était d’utiliser une approche individuelle qui prenne en compte la diversité de perception, de manipulation et de description des panélistes pour la caractérisation sensorielle. De plus, pour étudier l'effet d’expertise préalable, deux panels ont évalué les produits : des consommateurs et des experts. Une approche combinée de deux méthodologies différentes avec deux différents types de verbalisation (Description libre suivi par un Profil Flash) a permis d’identifier des spécificités dans la façon de répondre des deux panels. La description libre a montré les similitudes et les différences entre les terminologies des deux panels. Elle a montré que les experts produisent en moyenne plus de termes que les consommateurs. Cependant, certains de leurs termes sont spécifiques et n'ont jamais été cités par les consommateurs. Le Profil Flash a montré qu'il y a quelques caractéristiques qui deviennent importantes lorsque les panélistes évaluent l’ensemble des produits simultanément. Le résultat a montré des différences importantes entre les cartes produites des consommateurs et des experts issues de la méthode de Description libre. Cependant, les cartes sensorielles obtenues après le Profil Flash étaient très semblables pour les deux panels et proche de la carte obtenue pour le jury de consommateurs avec la méthode de Description libre. Quelques attributs spécifiques ont été fréquemment cités pour des évaluations de produits par les deux méthodes appliquées, comme le terme "Collant".Le deuxième objectif était d'établir une évaluation instrumentale des produits sur la base des résultats sensoriels pour ainsi mieux déterminer des méthodes et conditions pertinentes de caractérisation en regard des perceptions identifiées. Nous avons donc utilisé les descriptions et observations de mesures sensorielles pour choisir des méthodes instrumentales appropriées. Sur cette base, des méthodes rhéologiques classiques (mesures de propriétés viscoélastiques et pénétrométrie) et une mesure de tack adaptée ont été utilisées pour la caractérisation des produits. De plus, les produits ont été caractérisés dans deux états physiques (sans ou après un traitement mécanique important). La méthode de tack adaptée et la rhéologie aux petites déformations avec une géométrie à ailette ont permis de caractériser l'ensemble des produits présentant pourtant une diversité importante de texture (solide, semi-solide, liquide). Les résultats ont montré que la combinaison des deux méthodes améliore la représentation de l’espace produits et qu’elle apporte de nouveaux axes de description. La caractérisation instrumentale sur des produits traités mécaniquement n'a pas amené à une configuration sensiblement différente des produits.Le troisième objectif était de prévoir le positionnement sensoriel de produits (la carte de produit) et plus particulièrement la perception spécifique de certains attributs comme "Collant", à partir des mesures instrumentales. Une prédiction plutôt satisfaisante de la perception des produits par le jury de consommateurs est obtenue à partir des mesures de propriétés viscoélastiques en dynamique (module conservatif et seuil de contrainte) et des paramètres issus du test de tack (énergie totale et distance à la force maximale). De plus, la perception sensorielle du terme «collant » est bien prédite par le paramètre instrumental seuil de contrainte pour la majorité de consommateurs qui ont utilisé ce terme dans leurs évaluations
In our study the texture of a set of model processed cheeses is characterized through both sensory and instrumental approaches. Three objectives guided our work. The first was using an individual approach that takes the diversity in terms of perception, manipulation and description into account for sensory characterization of products. Furthermore, to study the effect of prior expertise, two panels evaluated the products: consumer and expert panel. A combined approach with two different methodologies and verbalization (Free comment followed by Flash Profile) made it possible to identify specificities in the answer behavior between the two panels. Free comment showed the similarity and differences between the terminologies of two panels. It showed that experts generate more terms in average than consumers. However, some of their terms are specific and never was cited to consumers. Flash profile showed that there are some characteristics that become important once the assessors evaluate the products simultaneously. The result showed important differences between the resulted product maps from consumers and experts after free comment method. However, the resulted sensory maps after the Flash Profile were very similar for both panels and were close to the sensory map obtained for consumer panel after free comment. Some specific attributes were frequently cited for products evaluations in two applied methods, such as “Collant (Stickiness)”.The second objective was to establish the instrumental characterization on the basis of sensory results in order to better determine some efficient methodologies and conditions to characterize the identified perceptions. We thus used sensory descriptions and observations to choose appropriate instrumental methods. On this basis, classic rheological methods (measurement of the viscoelastic properties and penetrometry) and adapted tack method were used for product characterization. Furthermore, the products were characterized at two physical states (without or after a mechanical treatment). The adapted tack method and the rheology at small deformation with vane geometry permitted to characterize the products set with important texture diversity (solid, semi-solid, liquid). The results showed that the combination of two methods improves the product map and brings new axes of description. The instrumental characterization of mechanically treated products did not lead to a rather different products configuration.The third objective was to predict the sensory positioning of products (product map) as well as the specific multidimensional perception “Collant (Stickiness)”, by instrumental measurements. A rather satisfactory prediction of consumer perception of texture was obtained through viscoelastic measurements (storage module and yield stress) and parameters stemming from tack measurement (total energy and distance at maximum tensile force). Furthermore, the sensory perceptions relative to “Collant (Stickiness)” is well predicted by the instrumental parameter “yield stress” for the majority of the consumers who applied this term in their evaluations

Le Laos est un pays enclavé et faiblement peuplé qui se trouve aujourd’hui, après plusieurs décennies de conflits liées à la décolonisation et à la guerre froide, au cœur d’un processus d’intégration économique régionale. Une croissance économique très rapide, soutenue par le développement massif des infrastructures de transport et d'exploitation des ressources naturelles, a des conséquences aussi importantes que différenciées sur les populations et leurs moyens d’existence. Les concepts de résilience et de vulnérabilité ont été employés dans différentes disciplines pour analyser et gérer des dynamiques sociales et écologiques face à des changements rapides et incertains. Parfois mis en opposition ou imbriqués, ces deux concepts s’insèrent dans une diversité de cadres d’analyse des relations société-environnement. Si l’ensemble des travaux étudiés soulignent la nécessité d’employer de multiples échelles d’analyse pour prendre en compte la complexité des phénomènes étudiés, ils n’évaluent cependant pas la vulnérabilité et la résilience aux mêmes niveaux : certains sont centrés sur les acteurs, tandis que d’autres considèrent des systèmes socioécologiques englobants. Or, les enjeux considérés comme prioritaires par les auteurs influencent l’échelle et les limites du système dont est évaluée la résilience ou la vulnérabilité. En amont d’un tel diagnostic, il semble donc nécessaire d’identifier les enjeux de résilience et de vulnérabilité que l’on souhaite aborder. Mais cette tâche dépasse selon nous les compétences des seuls scientifiques, et doit être ouverte à d’autres acteurs. La question est alors : comment peut-on prendre en compte des points de vue multiples dans la conceptualisation du système à évaluer ? Pour cela, nous proposons un cadre conceptuel qui considère un système socioécologique à la fois comme une représentation particulière de l’environnement construite par un acteur, et comme un ensemble finalisé d’éléments, organisé en une hiérarchie de niveaux d’observation, répondant chacun à une finalité, ou fonction. Nous avons alors élaboré et testé une démarche visant à recueillir les représentations systémiques qu’ont différents acteurs de leur environnement, c’est-à- dire la façon dont ils structurent un système socioécologique qui fait sens pour eux, en fonction des finalités qu’ils assignent à leur environnement. Cette démarche a été testée dans le bassin versant de la rivière Nam Lik, district de Fuang, province de Vientiane, qui abrite depuis 2010 le barrage hydroélectrique de Nam Lik 1-2. Une série d’ateliers ont été organisés auprès d’habitants de la zone d'étude, d’employés de l’administration locale et d’enseignants de l’université nationale du Laos. En amont d’un éventuel diagnostic de la vulnérabilité ou de la résilience du terrain d'étude, la thèse propose donc une réflexion sur les différents cadrages possibles de ces concepts, et sur les méthodes permettant de les recueillir auprès d’acteurs multiples
Lao PDR is a landlocked country with low population density, which stands nowadays in a process of regional economic integration, after suffering wars related to decolonization and Cold War during several decades. A very fast economic growth, based on the development of infrastructures of transport and natural resource exploitation, has led to large differentiated impacts on populations and their resource based livelihoods. The concepts of resilience and vulnerability have been used in different disciplines to analyze and manage the dynamics of geographical areas and social groups facing rapid and uncertain changes. Both concepts are used within a variety of frameworks of analysis of society-environment relationships. While all reviewed frameworks take into account multiple scales of analysis in order to tackle the complexity of the studied phenomena, they do not, however, assess vulnerability and resilience at the same scales. In particular, some frameworks are actor-centered, while others are system-centered. The scale and limit of the socioecological system whose resilience or vulnerability is assessed depend on the issues that the authors want to tackle. Before such an assessment, it seems necessary to identify the issues of resilience and vulnerability that we want to address. This task should not be taken over by scientists alone, but by other stakeholders as well. The question is: how can we incorporate multiple viewpoints in the system design? For this, our framework considers a socioecological system both as a specific representation of the environment offered by a stakeholder, and as a set of elements contributing to one function. This system is organized in a hierarchy of levels of observation, in which each level corresponds to an intermediary function. We developed and tested a process to collect system representations of the environment from various stakeholders, that is to say, the way they structure a socioecological system that makes sense to them, according to the purposes that they assign to their environment. This approach has been tested in the catchment area of the Nam Lik river, Fuang district, Vientiane province, where the Nam Lik 1-2 hydropower dam was built in 2010. A series of workshops were held with residents of the study area, employees of local government and Lao National University teachers. At the earliest stage of a vulnerability or resilience assessment in the field study, this thesis proposes a reflection on the possible framings of these concepts, as well as methods to collect them from multiple stakeholders

Avec l'evolution de la complexite et des performances des circuits integres complexes, le test de ces circuits devient de plus en plus difficile. Une des solutions actuellement envisagee pour pallier ce probleme consiste a integrer sur le circuit une structure de test, c'est-a-dire, un generateur de vecteurs de test et un analyseur de signature. Dans le cadre de cette these, nous nous sommes plus particulierement interesses aux structures de generation de vecteurs de test integrees. Un certain nombre de structures ont ete developpees specifiquement pour generer les vecteurs de test de maniere interne. Toutefois, peu d'entre elles ont ete realisees en considerant les specificites des pannes temporelles, leur efficacite ayant en effet ete analysee surtout par rapport au modele de pannes de collage. Le but de cette these est de concevoir une structure de generation integree permettant de tester les pannes temporelles. Apres avoir presente toutes les notions fondamentales sur les pannes temporelles, nous avons ensuite aborde le probleme de generation integree de vecteurs dans le cadre du test de pannes temporelles. Compte tenu de la difficulte a produire des paires de vecteurs de test efficaces, nous avons propose une nouvelle architecture de generation de vecteurs dediee a la detection de pannes temporelles dans les circuits combinatoires. Nous avons ensuite adapte cette solution au test de circuits sequentiels dans un environnement scan. L'analyse des resultats a montre l'interet des structures proposees par rapport aux autres methodes, aussi bien en termes de surface d'implantation que de temps de test.

The Western Australian School of Mines (WASM) developed a large area static test facility to enable the evaluation of three forms of surface support; namely, mesh, shotcrete and membranes. The purpose of this thesis is to document the test conditions and procedures under which these tests were conducted and to document the outcomes from testing.A review of previous mesh testing established that the most common method used for the evaluation of mesh types was two-dimensional linear elastic analyses, often using catenary principles. These analysis techniques have been used to estimate the tension in the wires of mesh and the strength characteristics of the mesh. These methods assume that forces are only transferred along directly loaded wires and that failure of the mesh is only related to the tensile strength of the wire.The force – displacement response from fully restrained mesh tests conducted at the WASM test facility have been characterised into distinct phases, clearly demonstrating the non-linear behaviour of mesh. The initial force response to displacement is slow; however the force response increases dramatically with further displacement. This behaviour has been shown to follow a cubic relationship.The force – displacement results have also been used to develop load transfer concepts for both weld mesh and chain link mesh. These concepts suggest that forces are transferred away from the directly loaded wires through adjoining wires, distributing forces over a greater area of the mesh. The force capacity of the weld mesh is not only dependent on the tensile strength of the wire but also the quality of the welding process. Likewise, the force capacity of chain link mesh is not only dependent on the tensile strength of the wire but also diamond configuration which allows load to be shared across a greater area of mesh.Several other test conditions were evaluated as part of the test program, including mesh sheet overlaps and wire orientation. The results have demonstrated that the boundary conditions and mesh orientation alters the force – displacement response of mesh.Most current shotcrete testing techniques focus on quality assurance and quality control. Shotcrete support mechanism and failure mechanisms are complex and not well understood. The WASM punch test method was developed to evaluate shotcrete using realistic shotcrete failure mechanisms such as shear and flexural failure and adhesion loss.The behaviour of shotcrete is characterised by an initial stiff reaction followed by rupture of the cement matrix. Rupture generally occurs at displacements of less than 5mm. The rupture force of fibre reinforced shotcrete is dependent only on the cement content of the shotcrete mix and the thickness of the layer, and not on the fibre type. The post rupture reaction of shotcrete is dependent on the reinforcing material; namely fibres or mesh. Mesh reinforced shotcrete had much greater force and displacement capacity compared with fibre reinforced shotcrete.Membranes have two theoretical support models (Norcroft, 2006); namely, the membrane support model and the beam support model. A total of 6 tests were undertaken to investigate the behaviour of a particular membrane product under the two theoretical support models. These tests were aimed at determining a suitable test method that could determine the capacity of the membrane and the behaviour of the membrane under realistic loading conditions.The results from both test programs demonstrated that the membrane has limited force and displacement capacity and cannot be compared with conventional mesh and shotcrete as suggested in the product data sheet. The failure mechanism was shear failure with minimal adhesion loss observed.The development of the WASM test facility has enabled the evaluation and comparison of various surface support elements. The results of this testing have provide a valuable insight into the performance of each of the individual products.

Global-local finite element analyses were used to study the damage tolerance of curvilinearly stiffened panels; fabricated using the modern additive manufacturing process, the so-called unitized structures, and that of adhesive joints. A damage tolerance study of the unitized structures requires cracks to be defined in the vicinity of the critical stress zone. With the damage tolerance study of unitized structures as the focus, responses of curvilinearly stiffened panels to the combined shear and compression loadings were studied for different stiffenersâ height. It was observed that the magnitude of the minimum principal stress in the panel was larger than the magnitudes of the maximum principal and von Mises stresses. It was also observed that the critical buckling load factor increased significantly with the increase of stiffenersâ height. To study the damage tolerance of curvilinearly stiffened panels, in the first step, buckling analysis of panels was performed to determine whether panels satisfied the buckling constraint. In the second step, stress distributions of the panel were analyzed to determine the location of the critical stress under the combined shear and compression loadings. Then, the fracture analysis of the curvilinearly stiffened panel with a crack of size 1.45 mm defined at the location of the critical stress, which was the common location with the maximum magnitude of the principal stresses and von Mises stress, was performed under combined shear and tensile loadings. This crack size was used because of the requirement of a sufficiently small crack, if the crack is in the vicinity of any stress raiser. A mesh sensitivity analysis was performed to validate the choice of the mesh density near the crack tip. All analyses were performed using global-local finite element method using MSC. Marc, and global finite element methods using MSC. Marc and ABAQUS. Negligible difference in results and 94% saving in the CPU time was achieved using the global-local finite element method over the global finite element method by using a mesh density of 8.4 element/mm ahead of the crack tip. To study the influence of different loads on basic modes of fracture, the shear and normal (tensile) loads were varied differently. It was observed that the case with the fixed shear load but variable normal loads and the case with the fixed normal load but variable shear loads were Mode-I. Under the maximum combined loading condition, the largest effective stress intensity factor was very smaller than the critical stress intensity factor. Therefore, considering the critical stress intensity factor of the panel with the crack of size 1.45 mm, the design of the stiffened panel was an optimum design satisfying damage tolerance constraints. To acquire the trends in stress intensity factors for different crack lengths under different loadings, fracture analyses of curvilinearly stiffened panels with different crack lengths were performed by using a global-local finite element method under three different load cases: a) a shear load, b) a normal load, and c) a combined shear and normal loads. It was observed that 85% data storage space and the same amount in CPU time requirement could be saved using global-local finite element method compared to the standard global finite element analysis. It was also observed that the fracture mode in panels with different crack lengths was essentially Mode-I under the normal load case; Mode-II under the shear load case; and again Mode-I under the combined load case. Under the combined loading condition, the largest effective stress intensity factor of the panel with a crack of recommended size, if the crack is not in the vicinity of any stress raiser, was very smaller than the critical stress intensity factor. This work also includes the performance evaluation of adhesive joints of two different materials. This research was motivated by our experience of an adhesive joint failure on a test-fixture that we used to experimentally validate the design of stiffened panels under a compression-shear load. In the test-fixture, steel tabs were adhesively bonded to an aluminum panel and this adhesive joint debonded before design loads on the test panel were fully applied. Therefore, the requirement of studying behavior of adhesive joints for assembling dissimilar materials was found to be necessary. To determine the failure load responsible for debonding of adhesive joints of two dissimilar materials, stress distributions in adhesive joints of the nonlinear finite element model of the test-fixture were studied under a gradually increasing compression-shear load. Since the design of the combined load test fixture was for transferring the in-plane shear and compression loads to the panel, in-plane loads might have been responsible for the debonding of the steel tabs, which was similar to the results obtained from the nonlinear finite element analysis of the combined load test fixture. Then, fundamental studies were performed on the three-dimensional finite element models of adhesive lap joints and the Asymmetric Double Cantilever Beam (ADCB) joints for shear and peel deformations subjected to a loading similar to the in-plane loading conditions in the test-fixtures. The analysis was performed using ABAQUS, and the cohesive zone modeling was used to study the debonding growth. It was observed that the stronger adhesive joints could be obtained using the tougher adhesive and thicker adherends. The effect of end constraints on the fracture resistance of the ADCB specimen under compression was also investigated. The numerical observations showed that the delamination for the fixed end ADCB joints was more gradual than for the free end ADCB joints. Finally, both the crack propagation and the characteristics of adhesive joints were studied using a global-local finite element method. Three cases were studied using the proposed global-local finite element method: a) adhesively bonded Double Cantilever Beam (DCB), b) an adhesive lap joint, and c) a three-point bending test specimen. Using global-local methods, in a crack propagation problem of an adhesively bonded DCB, more than 80% data storage space and more than 65% CPU time requirement could be saved. In the adhesive lap joints, around 70% data storage space and 70% CPU time requirement could be saved using the global-local method. For the three-point bending test specimen case, more than 90% for both data storage space and CPU time requirement could be saved using the global-local method.
Ph. D.

During 2012, the employer of this essay carried out a telephone survey with 18000 participants and a web panel survey with 708 participants. Those who partook in the telephone survey were given a choice to join the web panel. The purpose of this work is to study the participants of the telephone survey and see if they reflect the Swedish population with regards to several socio-demographic factors. Also, we intend to investigate if the propensity to join the web panel differs for participants of the telephone survey with regards to various socio-demographic affiliations. It is also of interest to study if the response pattern is different for participants of the telephone survey that would like to join the web panel and those who reject. A comparison of response pattern between the telephone survey and web panel survey has also been done, to see if there exist any differences for these two groups of surveys. The statistical methods used in this essay are descriptive statistics, multiple logistic regression and decision trees. Conclusions to be drawn with result from these methods are that the participants from the telephone survey do reflect the Swedish population regarding certain socio-demographic factors and that there is a slight difference in propensity to join the web panel for people which have dissimilar socio-demographic affiliation. It has also been found that there is a slight difference in response pattern for participants who would or would not like to join the web panel, as well as differences in response pattern also exist between the telephone survey and the web panel survey.

Cette these s'inscrit dans le cadre du test de pannes temporelles et concerne plus particulierement le diagnostic. Les pannes temporlles, ou fautes de delai, modelisent des defauts physiques (fabrication) ou des defauts de conception qui perturbent le fonctionnement normal d'un circuit a haute frequence uniquement. Nous proposons une methode de diagnostic dediee aux pannes temporelles pour traiter les circuits sequentiels synchrones. Cette approche represente une alternative a la simulation de fautes et repose sur une simulation multi-valuee et un trace de chemins critiques. Elle permet d'obtenir, par regroupement des chemins traces, une localisation approchee du site de la panne. Les resultats obtenus avec les circuits de reference iscas'89 ont valide l'efficacite de cette methode. La precision du diagnostic depend de la sequence de test. Il est possible d'ameliorer cette precision en generant des vecteurs de test en vue du diagnostic. Compte tenu des limitations des techniques deterministes (temps d'execution prohibitifs) et aleatoires (aucun controle de la creation des vecteurs de test), nous proposons une methode de generation de vecteurs de test orientee diagnostic basee sur les algorithmes genetiques. Cette approche permet d'obtenir, a partir d'une sequence de test initiale aleatoire, des vecteurs de test qui presentent de bonnes aptitudes a distinguer des fautes de delai les unes des autres, sans augmenter la longueur de test. Les resultats obtenus avec les circuits de reference iscas'85 ont permis de valider l'efficacite de cette approche par rapport aux techniques deterministes et/ou aleatoires

Dynamic panel data models are widely used by econometricians to study over time the economics of, for example, people, firms, regions, or countries, by pooling information over the cross-section. Though much of the panel research concerns inference in stationary models, macroeconomic data such as GDP, prices, and interest rates are typically trending over time and require in one way or another a nonstationary analysis. In time series analysis it is well-established how autoregressive unit roots give rise to stochastic trends, implying that random shocks to a dynamic process are persistent rather than transitory. Because the implications of, say, government policy actions are fundamentally different if shocks to the economy are lasting than if they are temporary, there are now a vast number of univariate time series unit root tests available. Similarly, panel unit root tests have been designed to test for the presence of stochastic trends within a panel data set and to what degree they are shared by the panel individuals. Today, growing data certainly offer new possibilities for panel data analysis, but also pose new problems concerning double-indexed limit theory, unobserved heterogeneity, and cross-sectional dependencies. For example, economic shocks, such as technological innovations, are many times global and make national aggregates cross-country dependent and related in international business cycles. Imposing a strong cross-sectional dependence, panel unit root tests often assume that the unobserved panel errors follow a dynamic factor model. The errors will then contain one part which is shared by the panel individuals, a common component, and one part which is individual-specific, an idiosyncratic component. This is appealing from the perspective of economic theory, because unobserved heterogeneity may be driven by global common shocks, which are well captured by dynamic factor models. Yet, only a handful of tests have been derived to test for unit roots in the common and in the idiosyncratic components separately. More importantly, likelihood-based methods, which are commonly used in classical factor analysis, have been ruled out for large dynamic factor models due to the considerable number of parameters. This thesis consists of four papers where we consider the exact factor model, in which the idiosyncratic components are mutually independent, and so any cross-sectional dependence is through the common factors only. Within this framework we derive some likelihood-based tests for common and idiosyncratic unit roots. In doing so we address an important issue for dynamic factor models, because likelihood-based tests, such as the Wald test, the likelihood ratio test, and the Lagrange multiplier test, are well-known to be asymptotically most powerful against local alternatives. Our approach is specific-to-general, meaning that we start with restrictions on the parameter space that allow us to use explicit maximum likelihood estimators. We then proceed with relaxing some of the assumptions, and consider a more general framework requiring numerical maximum likelihood estimation. By simulation we compare size and power of our tests with some established panel unit root tests. The simulations suggest that the likelihood-based tests are locally powerful and in some cases more robust in terms of size.
Solving Macroeconomic Problems Using Non-Stationary Panel Data

Le test des circuits integres permet de verifier le fonctionnement des circuits de plus en plus complexes elabores de nos jours. En ajoutant des modules de test sur les circuits integres eux-memes (test integre), cette verification peut etre effectuee a tous les moments de la vie du composant. Le but de cette these est d'ameliorer l'architecture du module de generation de vecteurs de test (gvt) qui assure la production des stimuli de test appliques au circuit. Deux nouvelles architectures ont ete proposees permettant de mettre en evidence des defauts comme les fautes de delai ou de collage dans les circuits sequentiels et combinatoires. Elles allient toutes les deux la generation d'une sequence deterministe et d'une sequence aleatoire afin de garantir le meilleur taux de couverture. La premiere architecture basee sur un cas particulier de machine d'etat produit une suite ordonnee de vecteurs de test deterministe completee par une sequence aleatoire. On peut donc l'utiliser pour mettre en evidence des defauts dans les circuits sequentiels. La deuxieme architecture permet la detection de fautes de delai dans les circuits combinatoires en generant des paires de vecteurs de test. Elle consiste a construire un lfsr specifique en fonction des paires de vecteur a produire. Certaines optimisations (utilisation de valeurs non specifiees, simulation inverse, etude des relations gvt/generateurs automatiques de vecteurs de test) sont aussi proposees pour reduire le cout d'implantation en surface tout en garantissant la qualite maximale du test realise par le gvt

The research was focused on the three major structural elements of a typical cold-formed steel building - shear wall, floor joist, and column. Part 1 of the thesis explored wider options in the steel sheet sheathing for shear walls. An experimental research was conducted on 0.030 in and 0.033 in. (2:1 and 4:1 aspect ratios) and 0.027 in. (2:1 aspect ratio) steel sheet shear walls and the results provided nominal shear strengths for the American Iron and Steel Institute Lateral Design Standard. Part 2 of this thesis optimized the web hole profile for a new generation C-joist, and the web crippling strength was analyzed by finite element analysis. The results indicated an average 43% increase of web crippling strength for the new C-joist compared to the normal C-joist without web hole. To improve the structural efficiency of a cold-formed steel column, a new generation sigma (NGS) shaped column section was developed in Part 3 of this thesis. The geometry of NGS was optimized by the elastic and inelastic analysis using finite strip and finite element analysis. The results showed an average increment in axial compression strength for a single NGS section over a C-section was 117% for a 2 ft. long section and 135% for an 8 ft. long section; and for a double NGS section over a C-section was 75% for a 2 ft. long section and 103% for an 8 ft. long section.

The use of marketing research panels are a more and more frequently used source of information for studies within many different branches. The purpose of this report is to investigate the demographic composition of panels and compare it with the population of Sweden, a possible change in behaviour of respondents, and if the source of recruitment is the cause of possible differences in study results. The study was commissioned by Norstats Linkoping office. Sources for the data material include Norstat’s recruitment process and their two main panels with different recruitment sources. To enable a deeper investigation of behaviour we also constructed a survey that was sent to 2,714 members of Norstat’s internet panels.

The statistical analysis includes contingency table analysis, multiple logistic regression, and Poisson regression. The results show that the demographic composition does not fully cover all the aspects of the Swedish population and some groups are less represented than others. The behaviour tends to differ between panel members that have responded to three or less surveys compared to members that have responded to twenty or more surveys. Source of recruitment does not seem to affect the results of studies, but it has some effect on the demographic composition of marketing research panels.

Användandet av paneler som källa vid undersökningar har den senaste tiden blivit en allt vanligare företeelse. Denna rapport har för avsikt att undersöka panelers demografiska sammansättning och överensstämmande med Sveriges befolkning, eventuell ändring av svarsbeteende samt huruvida rekryteringskällan ger upphov till kvalitetsskillnader hos medlemmar i en panel. Företaget Norstat har med sitt kontor i Linköping figurerat som uppdragsgivare till arbetet. Datamaterialet till studien har uppkommit från Norstats rekryteringsprocess samt från företagets två huvudpaneler med olika rekryteringskällor. För att djupare undersöka svarsbeteende konstruerade vi även en enkätundersökning som skickades ut till 2 714 medlemmar i Norstats internetpaneler.

Den statiska analysen innefattar χ2-test, multipel logistisk regression samt Poissonregression. Resultaten påvisade att den demografiska sammansättningen i panelen inte fullt ut speglade Sveriges befolkning samt att vissa grupper undertäcks i högre utsträckning än andra. Svarsbeteendet hos medlemmar i paneler har en tendens att ändras från det att medlemmen har svarat på en till tre undersökningar, till det att den har svarat på tjugo undersökningar eller fler. Rekryteringskällan till en panel verkar inte ge upphov till några större skillnader i svarsresultat, men däremot finns vissa skillnader i demografisk sammansättning.

Active control has often been considered for low frequency control of noise radiated by trim panels inside aircraft or helicopter cabins. Trim panels are usually made of honeycomb core sandwich because of their high strength to mass ratio. Active control techniques applied to honeycomb panel have not always given results as good as expected and this thesis aims to understand these limitations based on validated mechanical models of the active panels. For the modeling of honeycomb panels, the main difficulty is to estimate equivalent properties for the core. A numerical homogenization procedure is introduced to estimate effective parameters of a shell/volume/shell model based on the correlation with periodic modes of a detailed 3D model. The use of periodic modes allows a detailed analysis of the influence of constituent properties, especially glue and skin. Tests show that the considered Nomex based honeycomb has significantly viscoelastic behavior. In the model, the viscoelastic behavior of the core is taken into account by a frequency dependence of material parameters. Piezoelectric actuators and sensors are included in the validated honeycomb model. Strategies for integration in a numerical design process are discussed. Finally, the static response to an applied voltage is shown to correspond to a blister shape with local bending of the skin rather than global bending of the panel. This behavior results in poor actuator performance, which is also found in a realistic panel configuration studied at ONERA.

Two studies were conducted to determine the effect of panelist participation frequency and specific aspects of questionnaire design on overall acceptance scoring in consumer central location tests. Regarding participation frequency, research subjects who participate frequently in some survey types are known to provide responses that differ from subjects who participate less frequently, known as panel conditioning. With respect to questionnaire design, overall acceptance (OA) question placement and usage of pre-evaluation instructions (PEI) in questionnaires for food sensory analysis may bias consumers' scores via carry-over effects. To investigate these concerns, data from consumer sensory panels previously conducted at a central location, spanning 11 years and covering a broad range of food product categories, was extracted, compiled, and analyzed. For the first study, data was analyzed to determine evidence of panel conditioning by measuring the effect of participation frequency on mean consumer OA scoring among frequent, moderate, and infrequent participants. Practical significance and occurrence of panel conditioning, defined as mean scoring differences of ≥ 0.50 on a discrete 9-point scale hedonic point, were examined. Results indicate that for overall acceptance, in general, mean scoring differences were not practically significant and did not signify occurrence of panel conditioning. For the second study, OA question placement was studied with categories designated as first (the first evaluation question following demographic questions), after non-gustation questions (immediately following questions that do not require panelists to taste the product), and later (following all other hedonic and just-about-right questions, but occasionally before ranking, open-ended comments, and/or intent to purchase questions). Additionally, each panel was categorized as having or not having PEI in the questionnaire; PEI are instructions that appear immediately before the first evaluation question and show panelists all attributes they will evaluate prior to receiving test samples. Post-panel surveys were administered regarding the self-reported effect of PEI on panelists' evaluation experience. OA scores were analyzed and compared (1) between OA question placement categories and (2) between panels with and without PEI. For most product categories, OA scores tended to be lower when asked later in the questionnaire, suggesting evidence of a carry-over effect. Usage of PEI increased OA scores by 0.10 of a 9-point hedonic scale point, which is not practically significant. Post-panel survey data showed that presence of PEI typically improved the panelists' experience. Using PEI does not appear to introduce a meaningful carry-over effect.

Le syndrome CHARGE (CS) est une maladie génétique rare caractérisée par de nombreuses anomalies congénitales, majoritairement causées par des altérations de novo du gène CHD7. Celui-ci code pour une protéine à chromodomaines, impliquée dans le remodelage ATP-dépendant de la chromatine. La grande majorité des altérations de CHD7 consiste en allèles nuls tels que des délétions, des substitutions non-sens ou des décalages du cadre de lecture. Nous avons réalisé le premier diagnostic moléculaire d’un patient Indonésien atteint du CS, en étudiant un panel de gènes (CHD7, EFTUD2, et HOXA1) par NGS (next-generation sequencing). Nous avons identifié une nouvelle mutation non-sens hétérozygote dans l’exon 34 du gène CHD7 (c.7234G>T ou p.Glu2412Ter). Par ailleurs, il n'existe pas d’analyse fonctionnelle qui permettrait de caractériser la pathogénicité des variants de la protéine CHD7 rencontrés chez des patients. C’est pourquoi l’objectif de ce travail est de mettre au point un test fonctionnel de la protéine CHD7, sous forme sauvage ou mutée. Pour cela, nous avons généré par mutagénèse dirigée des vecteurs codant pour trois variants faux-sens de CHD7 et le variant présentant une insertion de cinq acides aminés. Ensuite, les protéines CHD7, sous forme sauvage ou variante, ont été surexprimées dans la lignée HeLa. L’expression des protéines a été mise en évidence par western blot et par immunofluorescence. Pour étudier la fonctionnalité de CHD7, nous avons quantifié par RT-qPCR les transcrits de cinq gènes (l’ADNr 45S, SOX4, SOX10, MYRF, et ID2), dont la transcription est selon le littérature régulée par CHD7. Nous avons observé que l’expression de CHD7 sauvage entraînait une diminution significative et reproductible des quantités de transcrits correspondant à tous les gènes rapporteurs. Par contre, l’expression des quatre allèles variants de CHD7 n’avait aucun impact, ce qui suggère que ces variants ne sont pas fonctionnels. Par ailleurs, nous avons appliqué notre test biologique dans des cellules de la lignée SH-SY5Y, pour lesquelles nous avons introduit une mutation faux-sens dans le génome en utilisant la technique CRISPR/Cas9. Lorsque ce variant était exprimé, les niveaux de transcription des cinq gènes rapporteurs n’étaient pas significativement différents de ceux observés dans les cellules où les deux allèles de CHD7 avaient été invalidés. Par conséquent, les variants étudiés peuvent être répertoriés comme résultant de mutations causales du CS
CHARGE syndrome (CS) is a rare genetic disease characterized by numerous congenital abnormalities, mainly caused by de novo alterations of the CHD7 gene. It encodes a chromodomain protein, involved in the ATP-dependent remodeling of chromatin. The vast majority of CHD7 alterations consists in null alleles like deletions, non-sense substitutions or frameshift-causing variations. We report the first molecular diagnosis of an Indonesian CS patient by a targeted NGS (next-generation sequencing) gene panel (CHD7, EFTUD2, and HOXA1). We identified a novel heterozygous nonsense mutation in exon 34 of CHD7 (c.7234G>T or p.Glu2412Ter). Functional analyses to confirm the pathogenicity of CHD7 variants are lacking and urgently needed. Therefore, the aim of this study was to establish a functional test for wild-type (WT) or variants of CHD7 protein found in CS patients. Using an expression vector encoding CHD7, three variants harboring an amino acid substitution and one variant with a five-amino acid insertion were generated via site-directed mutagenesis. Then CHD7 proteins, either wild-type (WT) or variants, were overexpressed in HeLa cell line. Protein expression was highlighted by western blot and immunofluorescence. We then used real-time RT-PCR to study CHD7 functionality by evaluating the transcript amounts of five genes whose expression is regulated by CHD7 according to the literature. These reporter genes are 45S rDNA, SOX4, SOX10, ID2, and MYRF. We observed that, upon WT-CHD7 expression, the reporter gene transcriptions were downregulated, whereas the four variant alleles of CHD7 had no impact. This suggests that these alleles are not polymorphisms because the variant proteins appeared non-functional. Furthermore, we applied our biological assay in SH-SY5Y cell line in which endogenous CHD7 gene was mutated using the CRISPR/Cas9 technique. Then, we observed that when a CHD7 missense variant was expressed, the transcription levels of the five reporter genes were non-significantly different, compared with the cells in which both CHD7 alleles were knocked-out. Therefore, the studied variants can be considered as disease-causing of CS

Cette thèse est une contribution à l'analyse économique des institutions. Ces dernières années, de nombreux travaux ont permis de montrer que le retard des pays en développement (PED) en matière de développement économique, serait dû en particulier à l'inefficacité de leurs institutions. Il se dégage ainsi un consensus sur la nécessité de réformer les institutions dans les PED. Cependant, la littérature prend rarement en compte les coûts éventuels associés à l'amélioration de la qualité des institutions. De plus, on peut considérer que l'amélioration de la qualité des institutions peut induire des coûts à court terme, alors que ses bénéfices ne vont se matérialiser qu'à long terme. Ainsi, le décalage temporel des effets positifs de l'amélioration de la qualité des institutions pourrait réduire les incitations des PED à réformer leurs institutions. Par ailleurs, la littérature aborde très peu la question des facteurs susceptibles de favoriser la réforme des institutions dans les PED. Cette thèse tente d'apporter des éléments d'éclaircissement sur ces différents points et poursuit deux principaux objectifs. Notre premier objectif consiste à analyser la rationalité économique du choix d'une stratégie de développement économique basée sur l'amélioration de la qualité des institutions dans les PED. Autrement dit, en dépit d'un possible décalage temporel des effets positifs de l'amélioration de la qualité des institutions, nous cherchons à savoir s'il est économiquement justifié de réformer les institutions dans les PED. Notre second objectif consiste à analyser les facteurs susceptibles de favoriser la réforme des institutions dans les PED. Les principaux résultats issus d'analyses empiriques à base de données couvrant la période 1960-2005, confirment l'idée selon laquelle il est dans l'intérêt des PED de choisir une stratégie de développement économique basée sur la réforme de leurs institutions. De même, cette thèse montre qu'une combinaison efficace de facteurs internes -existence dans les PED d'institutions efficaces de contraintes sur l'exécutif- et de facteurs externes - participation des PED aux échanges internationaux d'investissements directs étrangers (IDE)- contribuerait à la réforme des institutions de droits de propriété privée dans les PED. En effet, nos analyses empiriques montrent que : (1) Une amélioration de la qualité des institutions démocratiques, des institutions de droits de propriété, et particulièrement des institutions de régulation est favorable à la soutenabilité de la croissance économique dans les PED. (2) L'amélioration de la qualité des institutions engendre des coûts à court terme et des bénéfices à long terme, mais les bénéfices de long terme l'emporteraient sur les coûts de court terme. Nous mettons en exergue un tel résultat à travers une comparaison des effets de court et de long terme des institutions démocratiques sur la croissance économique dans les PED. (3) La probabilité de réformer les institutions de droits de propriété privée augmente avec les flux entrants d'IDE dans les PED dotés d'institutions efficaces de contraintes sur l'exécutif.

Background: Stress tests have been increasingly used as a part of the supervisory tool by national regulators after the financial crisis, which can also be used to conduct authorities’ supervisory for determining bank capital levels, assessing the health of a bank. Purpose: The main purpose of this study is to assess whether some micro factors play important roles on the changes of Common Equity Tier One Capital Ratio (between the bank accounting value and the stress testing results under the adverse scenarios).  Our secondary purpose is to investigate if our empirical results will help to provide some theoretical suggestions to regulators when they exercise stress tests.   Method: An empirical analysis by using Panel Data, introducing GARCH model to measure volatility.   Empirical foundation: The results of EU-wide stress tests and bank financial statements   Conclusion: The coefficient associated with non-performing loans to total loans is positively significant and the coefficient associated with bank size is negatively significant.  In addition, the financial system of strong banks is better to absorb financial shocks. These findings are useful, as banks is a reflection of the financial stability of an economic entity, we can use these findings as another reason to pay attention to the process of the stress testing rather just stress testing results.

Ce travail concerne l'étude d'un système multi-modèle d'aide à la génération d'arbres de test. Son application a été menée sur les systèmes électroniques de commande embarqués sur véhicules automobiles. Le travail présenté met en évidence les problèmes actuels du développement manuel des arbres de test et propose une solution basée sur l'utilisation conjointe de plusieurs modèles du système traité. Dans l'architecture présentée, chaque modèle est considéré comme une entité indépendante qui participe à la construction de l'arbre de test en rendant des services. Ce processus est supervisé par une autre entité qui est dépositaire de la stratégie globale de test. Trois modèles ont été développés : un modèle fonctionnel, un modèle de comportement électrique normal et un modèle de comportement électrique anormal. La connaissance utilisée, les technique de génération de test et les services renuds dans un cadre multi-modèle sont décrits pour chaque modèle. Un maquette informatique a été réalisée. / Les arbres de test fournis ont été testés sur un système d'injection de carburant et évalués par rapport aux arbres de test existants.

Doutoramento em Gestão
Esta dissertação visa estudar a performance corporativa dos clubes ingleses de futebol profissional, bem como os determinantes da performance dos clubes, com destaque para o efeito dos jogadores formados pelas Academias. O estudo evidencia existir uma associação positiva e significativa entre a performance financeira e desportiva dos clubes ingleses ao longo das épocas de 1993/94 a 2010/11. Os testes de cointegração indicam a existência uma relação estrutural de longo-prazo entre as variáveis desportivas e financeiras. Este estudo proporciona suporte à corrente da literatura que refere a maximização da performance desportiva sujeita a uma restrição de sustentabilidade financeira de longo prazo, como os principais objectivos dos clubes de futebol. Os testes de causalidade de Granger mostram que existe relações causais diferenciadas entre clubes. Os jogadores formados pelos próprios clubes tiveram um impacto negativo no desempenho desportivo e receitas, mas um efeito positivo na redução dos gastos salariais. A opção por jogadores formados por outros clubes ingleses teve uma influência negativa na performance desportiva, mas um efeito positivo na rendibilidade e despesas salariais dos clubes. Os resultados sugerem a necessidade de melhorar a produtividade do sistema de desenvolvimento de jovens jogadores em Inglaterra. Finalmente, observámos que os clubes ingleses são heterogéneos sinalizando a existência de peculiaridades em cada clube que são importantes para compreender o a performance alcançada e como desenvolvem as suas vantagens competitivas sustentáveis.
This dissertation examines the corporate performance of English professional football clubs and the determinants of clubs’ performance, with particular emphasis on homegrown locally-trained players. The study shows that there is a positive and significant association between the financial and sporting performance of English clubs over the 1993/94 to 2010/11 seasons. Cointegration tests show that sporting performance and financial variables are linked by a set of long-run structural relationship. Our study lends supports to the theoretical stream that argues that the maximisation of sporting goals, subject to constraint of long- term financial sustainability, are the two main objectives of football clubs. Granger causality tests show that there are different causal relationships between clubs. Homegrown club-trained players had a negative impact on the sporting performance and revenue functions, yet they had a positive effect on reducing salary expenditure. Association-trained players option had a negative influence on the sporting performance function, but a positive effect on profitability and wage expenses for English football clubs. The results suggest that there is a need to improve the productivity of the system for developing young players in England. Finally, we observed that English clubs are heterogeneous, which signals that idiosyncrasies exist in each club, which is important for understanding both performance and how to develop sustainable competitive advantages.

The current study examined the relationship between depression and uncertainty within the stress-diathesis model. Depression is a mental health disorder that is wide spread within our society. However, few causes of this disease have been able to be identified. Studies in uncertainty have shown that it is a major stressor in day-to-day life. Previous research has shown that individuals with high levels of uncertainty show higher levels of depression. The stress-diathesis model, a model originally developed to explain differences in development of schizophrenia, provides a theoretically meaningful way to combine these two concepts. The model states that a person who is likely to develop a disease has an internal mechanism, a diathesis, that will be triggered upon presentation of a stressor. This study tested the idea that uncertainty can be used as a stressor to activate diathesis within an individual, aiding in the prediction of depression. In total, 163 participants were randomly assigned one of three conditions, an uncertainty threat, an affirmation condition, and a control condition. Participants were given pre and post independent variable measures of depression and anxiety. Findings suggest that uncertainty activated negative emotions differentially within the participants, resulting in higher levels of negative affects after the uncertainty threat, especially for participants who already scored relatively higher on depression indicators. These results hint at a possible understanding of why depression rates and diagnosis rates of mental health issues rise during economic downturn and other times of strong uncertainty.

A pesquisa trata da relação entre as transações com partes relacionadas (RPT\'s) e o desempenho nas companhias do Novo Mercado. Teve como objetivo identificar se esta relação pode ser afetada pelos mecanismos de governança corporativa, especificamente de supervisão e monitoramento por elas adotados voluntariamente. Foram consideradas as hipóteses dicotômicas apresentadas por Gordon, Henry e Palia (2004), denominadas de \"conflitos de interesse\" e \" transações eficientes\". Na tentativa de mensurar estas relações, adotou-se o modelo de análise de dados em painel por permitir a incorporação de informações temporais e reduzir o problema do viés de variáveis omitidas. Evidências sugerem que há relação entre as transações com partes relacionadas operacionais e o desempenho das companhias estudadas. No entanto, os resultados a respeito do efeito de moderação dos mecanismos de supervisão e monitoramento na utilização de tais contratos foram inconclusivos.
The study deals with the relationship between related party transactions (RPT\'s) and firm performance in the Brazilian \"Novo Mercado\", and its goal is to identify whether this relationship can be affected by mechanisms of corporate governance. Audit committee was used to measure corporate governance mechanisms. The two assumptions made by Gordon, Henry and Palia (2004), called \"conflicts of interest\" and \"efficient transactions\" were considered in this study. In an attempt to measure these relationships, it was adopted the model of panel data analysis to reduce the problem of omitted variable bias. The empirical results provide evidence that there is a relationship between related party transactions and firm performance. However, the results regarding the moderating effect of the mechanisms of supervision and use of such contracts have been inconclusive.

Na teoria clássica de finanças, o sentimento do investidor não é considerado um fator importante sobre os preços das ações. Embora a existência do sentimento do investidor não seja negada, as teorias normalmente partem do princípio de que, em mercados financeiros competitivos, comportamentos de agentes quase-racionais são rapidamente eliminados. Esta tese tem o objetivo de investigar a relação entre o sentimento de mercado e as taxas de retorno futuras das ações. É proposta uma metodologia para a criação de um índice de sentimento específico para o mercado brasileiro com uso da análise de componentes principais. Com o objetivo de verificar a relação deste índice de sentimento com as taxas de retorno das ações, foi estimado um modelo de apreçamento em que esta variável foi incluída, para o período de 1999 a 2008. A amostra foi composta por empresas não-financeiras com ações listadas na BOVESPA, com uma negociabilidade mínima que garantisse observações suficientes e representativas para validar os resultados encontrados na pesquisa. O modelo de apreçamento foi estimado por GMM, levando em consideração o índice de sentimento de mercado, o risco sistêmico das empresas (medido pelo beta) e fatores como tamanho, índice market-to-book, alavancagem, momentum e crescimento da receita. Empregaram-se diferentes procedimentos para estimar os parâmetros dos modelos empíricos formulados, com o propósito de isolar influências espúrias, ocasionadas pela presença de heterogeneidade não-observada, pela existência de eventuais observações extremas ou mesmo pela possível endogeneidade dos regressores. Os resultados deste estudo empírico sugerem que o sentimento é um fator relevante no apreçamento das ações no mercado brasileiro. A relação negativa e significante entre o índice de sentimento e as taxas de retorno, encontrada consistentemente em diferentes modelos, indica um padrão de reversão nas taxas de retornos, ou seja, após um período de sentimento positivo, o impacto nas taxas de retorno no período seguinte é negativo, e vice-versa.
In classical finance theory investor sentiment is not considered an important factor in asset pricing. Although the existence of investor sentiment is not denied, theories assume that in competitive markets quasi-rational behavior is quickly offset by rational agents. The main goal of this thesis is to investigate the relationship between investor sentiment and future stock return rates. It is proposed a methodology to create a sentiment index specifically to the Brazilian market using principal components analysis. In order to analyze the relationship between this sentiment index and the future stock returns, it was estimated a pricing model including this variable for the period comprehending 1999 to 2008. Considering a negotiability restriction to assure representative and sufficient observations to validate a pricing model, the sample consisted of non-financial firms listed at BOVESPA. The pricing model was estimated by GMM considering the sentiment index, systematic risk (market beta) and factors as firm size, market-to-book ratio, leverage and return predictability measured by momentum or income growth. Different estimation procedures were applied to find empirical models coefficients which are less affected by spurious influence such as unobserved heterogeneity, outliers or possible regressors endogeneity. Results of the empirical study suggest that sentiment is a relevant factor in Brazilian asset pricing models. A negative and statistically significant relationship between the sentiment index and stock returns was consistently found in different models specifications. These findings suggest the existence of a reversion pattern in stock returns, meaning that after a positive sentiment period, the impact on subsequent stock returns is negative and vice-versa.

Nous nous proposons d'étudier, dans cette thèse, une question essentielle et relativement peu traitée dans les recherches françaises en sciences de l'éducation, elle concerne la genèse des acquisitions des élèves et leur évolution au cours de la scolarité. En nous appuierons sur la mobilisation des données longitudinales (panel 1997) ainsi que sur la mise en œuvre d'une expérimentation musicale à l'école maternelle, nous chercherons à répondre à ces questions : Comment se structurent et évoluent les premiers apprentissages des élèves dans le contexte scolaire et socioéconomique ? En quoi les capacités cognitives des élèves ont un impact sur leurs performances scolaires ? Est-ce que des activités spécifiques peuvent avoir un effet positif sur les compétences scolaires, via un accroissement des capacités cognitives ? Des analyses implicatives menées sur les données du panel ont mis en évidence la hiérarchisation des compétences des élèves et l'importance des capacités cognitives sur leur rendement scolaire. La revue de littérature regorge d'exemples probants qui attestent qu'il est possible d'accroitre les performances scolaires des élèves en développant certaines de ces capacités cognitives, et que la musique est un outil particulièrement efficace en ce sens. Nous avons donc cherché à tester empiriquement l'impact de la musique sur les capacités cognitives et sur les performances scolaires des élèves en effectuant une recherche expérimentale. Elle repose sur une méthodologie robuste qui garanti la validité des résultats qui en sont issus. Si les résultats des analyses de différence de différences, confirmés par les modèles de réponse à l'item, sont peu concluants quant à l'impact de la musique sur les progressions des capacités cognitives, nous avons montré et vérifié via le modèle d'Heckman que le traitement expérimental a un effet sur les performances scolaires des élèves.

A compreensão da dinâmica de persistência e evasão da atividade exportadora é fundamental para o desenho de incentivos adequados às firmas estreantes no mercado internacional e encontra respaldo nos modelos da nova teoria do comércio internacional. O propósito deste trabalho é investigar os determinantes do desempenho de firmas industriais brasileiras estreantes no mercado internacional, em termos de probabilidade de sobrevivência e evolução do valor exportado, com especial atenção aos impactos dos instrumentos de apoio Drawback, BNDES Exim e Proex. Para tanto, serão analisadas empresas estreantes no comércio exterior entre os anos de 1998 e 2003, configurando um painel desbalanceado com 8,5 mil firmas. Por meio de análise econométrica para dados em painel e estimação de modelos de duração, verificou-se que a função de sobrevivência e crescimento do valor médio exportado no tempo difere claramente entre firmas que utilizam um dos benefícios e aquelas que não o fazem. Também se pode afirmar que custos irreversíveis de entrada no comércio internacional não sejam desprezíveis entre as firmas industriais analisadas, o que indica que os programas públicos de promoção de exportações devam se concentrar na (i) redução da taxa de abandono das recém-exportadoras e (ii) na minimização dos custos fixos associados aos investimentos para entrada no mercado exportador.
Understanding the dynamics of persistence and evasion of export activity is essential for the design of export promotion for new exporters and international trade policies. Several results point to the importance of taking into account the specific sector of the industry in the implementation of public policies, which is supported by the new models of international trade theory. The purpose of this work is to investigate the determinants of the performance of Brazilian industrial new exporters, with particular attention to the impacts of Drawback, BNDES Exim and Proex. For this, we analyzed firms between the 1998 and 2003, constituting an unbalanced panel with 8500 firms. By panel data analysis and estimation of duration models, we found that the survival function and the growth of exports clearly differs among companies that use one of the programs and those that do not. One can also say that sunk costs are not negligible among the industrial firms analyzed, which indicates that public export promotion should focus on (i) reducing the dropout rate of new exporters and (ii) minimize the fixed sunk costs related with initial investments to begin the export activty.

Der Vortrag beschreibt wie sich mittels der unterschiedlichen Berechnungsverfahren zur Lösung dynamischer Strukturpobleme der Einschlag eines idealisierten Bruchstücks in eine Schutzwand berechnen lässt. Dies wird mittels zweier kommerzieller FEM-Programme beschrieben: a.) Creo Simulate nutzt zur Lösung die Methode der modalen Superposition, d.h., es können nur lineare dynamische Systeme mit rein modaler Dämpfung berechnet werden. Kontakt zwischen zwei Bauteilen lässt sich damit nicht erfassen. Die unbekannte Kraft-Zeit-Funktion des Einschlagvorganges muss also geeignet abgeschätzt und als äußere Last auf die Schutzwand aufgebracht werden. Je dynamischer der Einschlagvorgang, desto eher wird der Gültigkeitsbereich des zugrunde liegenden linearen Modells verlassen. b.) Abaqus/Explicit nutzt ein direktes Zeitintegrationsverfahren zur schrittweisen Lösung der zugrunde liegenden Differentialgleichung, die keine tangentiale Steifigkeitsmatrix benötigt. Damit können sowohl Materialnichtlinearitäten als auch Kontakt geeignet erfasst und damit die Kraft-Zeit-Funktion des Einschlages ermittelt werden. Auch bei extrem hochdynamischen Vorgängen liefert diese Methode ein gutes Ergebnis. Es müssen dafür jedoch weit mehr Werkstoffdaten bekannt sein, um das nichtlineare elasto-plastische Materialverhalten mit Schädigungseffekten korrekt zu beschreiben. Die Schwierigkeiten der Werkstoffdatenbestimmung werden in den Grundlagen erläutert
The presentation describes how to analyze the impact of an idealized fragment into a stell protective panel with different dynamic analysis methods. Two different commercial Finite Element codes are used for this: a.) Creo Simulate: This code uses the method of modal superposition for analyzing the dynamic response of linear dynamic systems. Therefore, only modal damping and no contact can be used. The unknown force-vs.-time curve of the impact event cannot be computed, but must be assumed and applied as external force to the steel protective panel. As more dynamic the impact, as sooner the range of validity of the underlying linear model is left. b.) Abaqus/Explicit: This code uses a direct integration method for an incremental (step by step) solution of the underlying differential equation, which does not need a tangential stiffness matrix. In this way, matieral nonlinearities as well as contact can be obtained as one result of the FEM analysis. Even for extremely high-dynamic impacts, good results can be obtained. But, the nonlinear elasto-plastic material behavior with damage initiation and damage evolution must be characterized with a lot of effort. The principal difficulties of the material characterization are described

A agropecuária brasileira tem crescido nas últimas décadas e os ganhos de produtividade tem sido importante neste bom desempenho do setor. O presente trabalho tem dois objetivos principais. O primeiro deles foi mensurar o crescimento desta produtividade total dos fatores na agropecuária brasileira estadual, decompondo o crescimento da PTF em progresso tecnológico e eficiência técnica. O segundo objetivo foi analisar o efeito do crescimento da PTF da agropecuária brasileira sobre os preços agrícolas, no Brasil, de 1970 a 2006. O crescimento desta produtividade foi mensurado a partir dos insumos terra, trabalho e capital na função de produção translog sob orientação do produto, a partir do método de Fronteira Estocástica de Produção e do índice de produtividade de Malmquist. Para avaliar o efeito do crescimento da PTF sobre os preços agrícolas foi construído o índice de preços agrícolas utilizando-se o Índice de preços de Laspeyres para estimar o vetor autoregressivo em painel (panel- VAR), acrescentando as variáveis produtividade total dos fatores (PTF), salário rural, financiamento agrícola e renda per capita domiciliar. Além disso, foi aplicado o teste de causalidade, no sentido de Granger, e estimada a função impulso resposta. A base de dados utilizada foi, obtida do Censo Agropecuário, a nível estadual, para os anos de 1970, 1975, 1980, 1985, 1995 e 2006. Os resultados indicaram que a taxa de crescimento da PTF foi crescente no Brasil e nos estados, sendo que, na maior parte das vezes, é explicada pelo progresso tecnológico, positivo e crescente para todos os estados. A eficiência técnica variou ao longo dos anos, apresentado taxas de crescimento médias positivas para a maioria dos estados. Em média, os estados estiveram situados abaixo da fronteira de produção da agropecuária brasileira. São Paulo foi o estado com maior nível de eficiência técnica. Embora a taxa de crescimento médio anual tenha sido positiva ao longo do período analisado, a eficiência reduziu para todos os estados analisados em 2006. Da análise dos efeitos do crescimento da PTF sobre os preços agrícolas, a PTF tem causalidade, no sentido de Granger, sobre os preços agrícolas. Na função impulso resposta, o choque inicial na variável PTF reduziu os preços nos primeiros anos. Assim, o crescimento da PTF do setor agropecuário contribuiu para o aumento da oferta de produtos, reduzindo os preços agrícolas. A maior disponibilidade de alimentos e, com a redução dos preços dos alimentos, os consumidores, principalmente os de renda mais baixa puderam ter maior acesso aos alimentos.
The Brazilian agriculture has grown in recent decades and productivity gains have been important in this good performance of the sector. This work had two main objectives. The first one was measure the growth of this total factor productivity in agriculture by the Brazilian\'s states, decomposing TFP growth by technological progress, technical efficiency and economies of scale. The second objective was to analyze the effect of TFP growth of Brazilian agriculture on agricultural prices. The growth in productivity was measured from the inputs like labor, gross and capital in the translog production function, from the Stochastic Frontier Analysis and of the outputoriented Malmquist productivity index. To analyze the effect of TFP growth on agricultural prices was constructed an index of agricultural prices through the Laspeyres price index to estimate the vector autoregressive panel (panel-VAR) and establish the relationships between TFP, rural wages, agricultural finance and income per capita household. The Granger causality test and the impulse response function were used to the data panel. The database used obtained from the Agricultural Census, at the state level for the years 1970, 1975, 1980, 1985, 1995 and 2006. The results showed that the growth rate of TFP has been growing in Brazil and in the states, and technological progress explained most of the growth being positive and growing for all states. Technical efficiency varied over the years, presented positive average growth rates for most states. The states were located below the production frontier of Brazilian agriculture and São Paulo was the state with the highest level of technical efficiency. Although the average annual growth rate has been increasing over the period analyzed, the efficiency decreased to all state analyzed in 2006. The results also showed that TFP growth has causality in the sense of Granger, on agricultural prices. In the impulse response function, the initial shock in TFP decreased prices in the early years. Thus, TFP growth of the agricultural sector contributed to the increased supply of agricultural products, reducing agricultural prices. The greater availability of food and with reducing food prices, consumers, especially those from lower income might had greater access to food.

Les séismes constituent une source d’aléas importante pour l’étude de la vulnérabilité d’unbâtiment. Le comportement parasismique des bâtiments à ossatures en bois est particulièrementintéressant. Deux familles de structure à ossature en bois peuvent être distinguées : les ossaturesutilisant les produits industriels que sont les panneaux en bois reconstitué servant à contreventerla structure et les connecteurs métalliques, et les ossatures traditionnelles avec remplissage reposantsur des techniques de construction anciennes et dépendantes du contexte local. L’efficacitédu comportement parasismique des bâtiments à ossature en bois traditionnels avec remplissagereste encore peu reconnue en raison du manque de résultats issus des travaux de recherche.Les travaux présentés dans cette thèse visent ainsi à améliorer les connaissances sur le comportementparasismique de cette typologie constructive. Partant de l’hypothèse selon laquellece comportement est gouverné par la réponse des assemblages par connecteurs métalliques, uneapproche multi-échelles, couplant études expérimentales et études numériques est développée.Elle détaille l’analyse à l’échelle 1 de la connexion, en passant par l’échelle 2 des cellules élémentaires,constitutives des murs, par l’échelle 3 des murs de contreventement pour se finaliserà l’échelle 4 du bâtiment dans son ensemble.Sur le plan expérimental, cette approche permet d’une part, de réaliser des études paramétriqueset ainsi d’appréhender l’influence de la réponse de chaque élément (bois, clous, feuillard,remplissage, contreventement, ouvertures) sur le comportement local (échelles 1 et 2) et global(échelles 3 et 4) de la structure. D’autre part, elle permet de fournir une base de données pourla validation des modélisations numériques aux différentes échelles.Sur le plan de la modélisation numérique, cette approche multi-échelles est fondée sur la priseen compte du comportement non-linéaire hystérétique des assemblages à l’échelle supérieure, parl’intermédiaire d’un macro-élément, développé dans la cadre de la méthode des éléments finis.Ainsi, grâce à une modélisation simplifiée (assemblage des macro-éléments), le calcul est rapide,aussi bien à l’échelle du mur qu’à celle du bâtiment, et intègre les phénomènes non-linéaire locaux.Le modèle peut ainsi prédire de manière relativement précise le comportement dynamique de lastructure complète à l’échelle 4, testée sur table vibrante.L’étude présentée dans ce manuscrit fait partie des travaux précurseurs relatifs à l’analysede la vulnérabilité sismique des ossatures bois avec remplissage. Cette étude débouche sur denombreuses perspectives pour l’analyse de cette typologie constructive. Elle confirme que les bâtimentsà ossatures en bois avec remplissage ont un comportement parasismique très performant
The seismic vulnerabilty is an important issue in the design of a building. The seismicresistant behavior of timber-framed structures is particularly relevant. Two types of timberframedstructures can be distinguished : the timber-framed structures using industrial products,such as wood-products panels used to brace the structure or metal fasteners, and traditionaltimber-framed structures included infill made of natuarl materials (earth or stones masonry).The seismic resistant behavior efficiency of traditional structures remains poorly recognizedbecause of the lack of research results on this kind of construction.Therefore, the thesis aims at improving the seismic behavior knowledge of timber-framedmasonry. Based on the assumption that their behavior is driven by the response of the metalfasteners connections, a multi-scale approach is proposed. It couples experimental and numericalstudies. At the scale 1 of the connection, at the scale 2 of the elementary constitutive cell ofwalls, at the scale 3 of structural elements such as shear walls and finally at the scale 4 of theentire building.In regards to the experimental work, this method allows, on the one hand, to perform parametricstudies and to analyze the influence of each element (wood member, nails, steel strip,infill, bracing, openings) on the local behavior (scales 1 and 2) and on the global behavior(scales 3 and 4) of the structure. On the other hand, it allows to provide a database to validatethe numerical modeling at each scale.In regards to the numerical work, this multi-scale approach allows to take into account thehysteretic behavior of joints in the development of a macro-element at the scale 2. Thus, thanksto a simplified finite element modeling (macro-element assembly), the computational cost islimited and it allows to take into account the local phenomena. The model is able to predictrelatively accurately the dynamic behavior at the scale 4 of the building, tested on a shakingtable.The study, presented herein, is one of the pioneer work that deals with the analysis of theseismic vulnerability of timber-framed structures with infill panels. This study provides outlookfor the analysis of this type of buildings. It confirms that the timbered masonry structures havea relevant seismic resistant behavior

A análise sensorial é uma metodologia científica utilizada para mensurar, avaliar e interpretar reações relacionadas às características de produtos tais como são percebidas através dos sentidos, respondendo à bem mais que simplesmente à preferência por algum produto em detrimento de outros. Métodos científicos específicos têm sido desenvolvidos para medir ou estimar objetivamente, com precisão e reprodutibilidade, as respostas humanas aos estímulos a que são submetidos. Os testes descritivos, que compõem parte da análise sensorial, exigem controle cuidadoso das possíveis variáveis capazes de interferir no resultado, tais como ambiente do teste, armazenamento das amostras, condições da pele dos painelistas, seleção e treinamento de atributos do produto a serem avaliados. A filosofia do treinamento é proporcionar uma mesma experiência sensorial aos painelistas através do uso de uma ampla variedade de amostras de referências, conceitos, terminologias, protocolos e escalas, o que é essencial para estabelecer um quadro comum de referências, cujo propósito é remover a conotação \"subjetiva\" desta metodologia sensorial. Ao fazer uso desta metodologia, obtivemos respostas coerentes, similares e com pequenos desvios padrão após treinamento de três meses com o painel, o qual foi capaz de diferenciar sete produtos comerciais hidratantes nos atributos estudados
Sensory analysis is a scientific method used to measure, analyze and interpret reactions related to product characteristics such as perceived through the senses, responding to much more than simply preference for one product over another. Specific scientific methods have been developed to measure or estimate objectively, accurately and reproducibility human responses to stimuli that they are submitted. Descriptive tests, which are part of sensory analysis, require careful control of possible variables that can affect the results, such as test environment, sample storage, skin conditions of the panelists, product attributes selection and training. The training philosophy is to provide the same sensory experience to panelists through the use of a wide variety of references samples, concepts, terminology, protocols, and scales, which is essential to establish a common frame of reference, whose purpose is to remove the\"subjective\" connotation from this sensory methodology. By using this methodology, we achieved consistente, similar and with small standard deviations answers, after three months of training with the panel, which was able to distinguish seven moisturizers commercial products into the studied attributes

One of the goals of the economic, social and territorial cohesion is to reduce regional disparities between member states of the European Union. For this purpose the structural funds and the Cohesion Fund were established(among other things). The theoretical part of this thesis presents the issue of regional disparities and ways how to measure them. In view of the lack of consistent definition of this concept, there are number of measurement and evaluation methods. Furthermore, the work focuses on the implementation of cohesion policy and ways of measurement of their impact on development and growth of regions. The practical part of this thesis presents, evaluates and compares the regional disparities between the regions of the Czech Republic and the Slovak Republic via selected methods and assesses the impact of the financial support provided from the Structural Funds and the Cohesion Fund in the programming period 2007 - 2013 on economic growth of regions in the Czech and Slovak Republics. Following indicators are included: gross domestic product, unemployment rate, gross fixed capital formation and the rate of economic activity. The influence of the subsidy on the economic growth of regions is validated through the panel data analysis, namely a panel model with fixed effects, and Granger causality test. First, we investigated the impact of this support on the economic performance of regions where it is verified whether there is a relationship between economic performance of NUTS III regions in the Czech and Slovak Republics, characterized by gross domestic product and the unemployment rate, and the amount of the subsidy. Furthermore, it is verified whether the amount of subsidy depends on the level of regional gross domestic product. Dissertation contributes to the discussion about the impact of support from EU funds in the Czech and Slovak Republics, focusing on the regional level, and answers the question of reducing regional disparities using the Structural Funds and the Cohesion Fund.

The first chapter compares two types of univariate endogenous one-break unit root tests, namely the Dickey-Fuller (DF) type and the Schmidt-Phillips Lagrange Multiplier (LM) type tests. To investigate the small-sample properties of these tests, they are applied to the Nelson-Plosser macroeconomic time series with bootstrapped critical values used for unit root inference. Simulation results show that breaks under the null for the observed data are of sufficient magnitude to lead to size distortion for the DF-type tests, whereas the LM-type tests generally exhibit satisfactory size performance and possess the invariance property. Furthermore, in implementing the LM-type tests, the one that uses the minimum sum of squared residuals break selection method demonstrates better performance over the one that employs the minimum statistic break selection method.
The second chapter proposes LM type panel unit root test procedures with structural changes based on the group mean and combination test approaches. The proposed test procedures allow for breaks under both the null and alternative, and capture heterogeneity due to individual specific characteristics. The same set of distributions of the underlying individual LM statistics can be utilized to compute the panel statistics for the cases with no breaks and with intercept breaks as a result of the invariance property. Simulation results demonstrate that the inverse normal test exhibits the best overall finite-sample properties measured in terms of size and power. When break dates are unknown, the minimum sum of squared residuals break selection method is preferred. The bootstrap approach is suggested to account for cross-sectional dependence.
The third chapter studies panel cointegration tests dealing with two manifestations of structural changes, viz. breaks in the cointegrating relationship and breaks in the trend functions of time series. The importance of accounting for these breaks is highlighted using a simulation study. Finite-sample properties of the Gregory-Hansen (GH) type and LM type tests incorporating breaks in the cointegrating relationship are assessed. Two variants of the LM type tests are further examined in the presence of cross-sectional dependence taking on a factor structure. In the course of test comparison, some modifications are also suggested. A novel test procedure, based on the LM approach, is devised when trend functions of time series are subjected to breaks. Unlike existing tests, this procedure permits unknown breaks under both the null and alternative that can differ in locations among the variables under study.
This thesis investigates panel unit root and cointegration tests with structural changes that are generalizations of their univariate counterparts. Small-sample properties of two well-established univariate test procedures are first assessed using the bootstrap approach. Extensions of these procedures in the panel framework are then examined.
"February 2008."
Adviser: Win Lin Chou.
Source: Dissertation Abstracts International, Volume: 69-08, Section: A, page: 3266.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (p. 298-305).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. Ann Arbor, MI : ProQuest dissertations and theses, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.

The dissertation consists of three chapters that study topics related to structural change, spatial and network data. The first chapter considers the problem of testing for a structural change in the spatial lag parameter in a panel model. We propose a likelihood ratio test of the null hypothesis of no change against the alternative hypothesis of a single change. The limiting distribution of the test is derived under the null hypothesis when the number of time periods is large. We also propose a break-date estimator to determine the location of the change point following evidence against the null hypothesis. We present Monte Carlo evidence to show that the proposed procedure performs well in finite samples. We use US state budget data to investigate changes in budget spillovers and the interdependence of fiscal policy within US states. The second chapter proposes a theory of cross-country migration in the form of labor mobility based on regional and sectoral productivity shocks in a multi-country, multi-sector setting. The productivity model when applied to US state data explains both the nominal and relative flow of workers across the U.S. well, which is taken as the frictionless benchmark. On the other hand, when applied to Europe the model explains the relative flow network well, but predicts a higher nominal flow. This missing mass of migrants is explained by socio-cultural-political barriers. We use dyadic regressions to assess the effects of institutional and cultural "distance" between countries in explaining the "European immobility puzzle". The third chapter shows that the "iron-law" of convergence (2\%) still holds for the world. We document a structural break in Africa's convergence rate and argue that Africa was not converging before 2000. The world convergence rate before 2000 was driven by Asian and Latin American countries. We show that recent institutional and infrastructural developments have led the African countries on the path of "catching up". We use Least-Absolute-Shrinkage-and-Selection-Operator (LASSO) to select the variables and a double selection method to estimate the treatment effect in a partially linear model. We compare LASSO variable selections with those obtained using Gradient-Boosting-Method (GBM) and Random Forest.

Tese no âmbito do Doutoramento em Engenharia Civil, apresentada à Faculdade de Ciências Tecnologia da Universidade de Coimbra
A madeira lamelada-cruzada (cross-laminated timber, CLT), tendência moderna em termos de construção em madeira, demonstra elevado potencial para sistemas maciços de construção de madeira. O conceito dos painéis CLT (camadas ortogonais) reduz significativamente a anisotropia dos painéis, garante maior estabilidade física e permite ligações mais fáceis e eficientes entre os elementos e destes com outros componentes da construção, tornando esses painéis uma solução versátil para suportar cargas fora/ e no plano dos mesmos. Este sistema possui vantagens significativas em relação à construção das tradicionais estruturas leves de madeira, abrindo um campo completamente novo para o uso da madeira na construção. Por outro lado, como se trata de um sistema maciço de madeira, é necessário um volume significativo de matéria-prima para produzir os painéis, aspeto que é apontado como uma das principais barreiras para a implementação do CLT de uma forma mais abrangente, porventura devido aos custos associados. Neste contexto, o objetivo da presente tese consistiu no desenvolvimento de uma solução de painel alternativa, ou pelo menos complementar, baseada em CLT, mas utilizando menos quantidade de madeira, combinando desempenho mecânico com melhor isolamento térmico e peso reduzido. A solução desenvolvida, denominada madeira isolada cruzada (cross-insulated timber, CIT), consiste em substituir a camada interna de um painel CLT de cinco camadas por uma à base de material de isolamento (espuma rígida de poliuretano), tendo, por isso, algumas semelhanças com o conceito de painel de madeira estrutural isolado (SIP). Os principais aspetos focados nesta tese, tendo em vista o desenvolvimento do painel incluem: (i) a definição da estrutura do painel e dos possíveis materiais para a sua constituição; (ii) a caracterização dos materiais selecionados para o desenvolvimento do painel, incluindo as camadas adesivas; (iii) a caracterização mecânica dos painéis; (iv) a otimização funcional e económica dos painéis; (v) a avaliação do impacte ambiental dos painéis; (vi) a caracterização acústica dos painéis; e (vii) o desenvolvimento de sistemas de conexão para os painéis. No primeiro aspeto, foi definida uma estrutura composta por um núcleo em espuma rígida de poliuretano entre dois pares de camadas cruzadas em madeira de Pinho bravo. Em alternativa, para as faces exteriores dos painéis, foi também considerada a Acácia Austrália. No segundo aspeto, os resultados de caracterização dos materiais permitiram verificar o comportamento complexo da espuma de poliuretano, tendo-se observado um comportamento não-linear e rotura dúctil em compressão e um comportamento linear e rotura frágil em tração. Da adesão entre materiais, concluiu-se que as adoção de pressões de aperto mais elevadas conduzem a uma melhor adesão dos mesmos e, dos ensaios de envelhecimento, concluiu-se que ao invés de uma redução da resistência, particularmente no poliuretano, houve um aumento da mesma devido à pós-reticulação do material. No terceiro aspeto, foi possível verificar que o modo de rotura dominante nos ensaios de flexão foi o corte do núcleo. Os modelos analíticos identificados na revisão do estado-da-arte descreveram bem o comportamento inicial observado (linear) e, para descrever a fase não-linear observada, os modelos numéricos desenvolvidos demonstraram um bom nível de precisão. No quarto aspeto, concluiu-se que a exigência de um desempenho térmico mínimo (envolvente exterior do edifício) torna a solução de painel desenvolvido na tese mais competitiva face aos painéis CLT. No quinto aspeto, através de uma análise de ciclo-de-vida, concluiu-se que a produção de poliuretano e a assemblagem do painel constituem os processos de produção com maior impacte ambiental; dos cenários de fim-de-vida considerados, a opção de incineração com recuperação de energia revelou ser a que implica menores impactes. Da comparação com sistemas de CLT, concluiu-se que o painel desenvolvido implica, de uma forma geral, maiores impactes. No sexto aspeto, verificou-se, o menor isolamento dos painéis de CIT face aos de CLT de igual espessura, devido à menor massa. Os modelos analíticos identificados no estado-da-arte para painéis sanduiche não se revelaram adequados para avaliação do isolamento a sons aéreos dos painéis, pelo que o modelo de Sharp para elementos isotrópicos e homogéneos com uma adaptação revelou uma melhor descrição dos mesmos; para descrição do isolamento a sons de percussão, a lei do invariante revelou-se eficaz. No sétimo aspeto foram desenvolvidas várias ligações, sendo que uma delas foi testada experimentalmente, e cuja resistência se enquadrou dentro do previsto pelos modelos analíticos identificados no estado-da-arte. Globalmente, o estudo realizado nesta tese mostrou que os painéis desenvolvidos têm potencial para complementar os atuais sistemas em CLT, nomeadamente no que diz respeito ao aos elementos da envolvente exterior.
Cross-Laminated Timber (CLT), a modern trend in timber construction, shows high potential for massive timber construction systems. Compared to traditional systems, the CLT panels’ layout (crosswise layers) significantly reduces the anisotropy of the panels, guarantees higher physical stability and allows for easier and more efficient connections between elements and other building components, making these panels a versatile solution to bear both out-of-plane and in-plane loads. This system has also significant advantages with respect to traditional wood light-frame construction, opening a completely new field for the use of timber in construction. On the other hand, as this is a massive wood system, a significant volume of wood raw material is required to produce the panels and this is pointed out as one of the main barriers for CLT implementation, perhaps due to the associated costs. In this context, the objective of the present thesis consisted of the development of an alternative, or at least complementary, CLT based panel solution but using less amount of wood, combining mechanical performance with improved thermal insulation and reduced weight. Such solution, named cross insulated timber (CIT), consists of replacing the inner layer of a five-layer CLT panel by an alternative one made of insulation material (polyurethane rigid foam), and thus having some similarities with the structural insulated timber panel (SIP) concept. The main aspects that are focused on this thesis for the panel development, include: (i) the definition of the panel layout and potential materials for its constitution; (ii) the characterization of the selected materials for the panel development, including the adhesive layers; (iii) the mechanical characterization of the panels; (iv) the functional and economic optimization of the panels; (v) the evaluation of the environmental impact of the panels; (vi) the acoustic characterization of the panels; (vii) the development of connection systems for the panels. In the first aspect, a structure consisting of a polyurethane core between two pairs of Maritime pine crossed layers was defined. As an alternative to this, for the exterior faces of the panels, Acacia Australia was considered. In the second aspect, the results of material characterization tests allowed to verify the complex behaviour of the polyurethane foam, which presents non-linear behaviour and ductile failure in compression, and linear behaviour and brittle failure in tension. From the adhesion between materials, it was concluded that the adoption of higher bonding pressures leads to better adhesion of the same ones and, from the ageing tests, it was concluded that instead of a reduction in strength, particularly in polyurethane, there was a strength increase due to additional cross-linking due to post-curing. In the third aspect, it was possible to verify that the dominant failure mode in the bending tests was core shearing. The analytical models identified in the state-of-the-art review described well the observed initial behaviour (linear) and, to describe the observed nonlinear phase, the numerical models developed demonstrated a good level of precision. In the fourth aspect, it was concluded that the requirement of a minimum thermal performance (in the case of the exterior envelope of the building) makes the panel solution more competitive against CLT panels. In the fifth aspect, through a life-cycle analysis, it was concluded that the production of polyurethane and the assembly of the panel constitute the production processes with the greatest environmental impact; among the considered end-of-life scenarios, the option of incineration with energy recovery proved to be the one with the least impacts. From the comparison with CLT systems, it was concluded that the developed panel presented, in general, greater impacts. In the sixth aspect, less insulation of the CIT panels compared to the CLT panels of equal thickness was registered, due to the lower mass. The analytical models identified in the state-of-the-art for sandwich panels did not prove to be suitable for assessing the airborne sound insulation of the panels, so the Sharp model for isotropic and homogeneous elements with an adaptation provided more accurate predictions; for describing the insulation to impact sounds, the invariant law proved to be effective. In the seventh aspect, several connections were developed, one of which was experimentally tested, and whose resistance fit within the predictions provided by the analytical models identified in the state-of-the-art. Overall, the study conducted in this thesis showed that the developed panels have the potential to complement the current CLT systems, namely concerning the elements of the external envelope.

O pão é um dos produtos mais consumidos no mundo inteiro, sendo assim parte fundamental de uma alimentação saudável, completa e equilibrada. Em Portugal apesar de parte integral dos hábitos alimentares da população, a sua ingestão sofreu um decréscimo nos últimos anos devido às alterações dos padrões de consumo. Numa época em que os consumidores são cada vez mais exigentes, procurando produtos convenientes, frescos e de qualidade, o pão viu-se obrigado a evoluir. Hoje variadas formas e formatos são produzidos de maneira a cativar esses mesmos consumidores, contudo a avaliação do pão é fortemente influenciada por parâmetros como a frescura, a cor e a textura, sendo a perceção da frescura um parâmetro complexo e muito difícil de descrever e avaliar, dada a variedade de pães que existem no mercado. Assim, o principal objetivo deste projeto constituiu em desenvolver um painel sensorial treinado capaz de avaliar as características do pão considerado tradicional pela empresa e, desta forma, encontrar pontos que possam ser melhorados, aperfeiçoando a qualidade do pão em questão. Aliando assim o crescente destaque que a análise sensorial tem recebido nos últimos anos, à otimização de um produto tradicional. Neste trabalho encontram-se descritas as diferentes fases para a constituição de um painel de provadores treinados, bem como a sua formação e seleção de acordo com as normas da análise sensorial.
Bread is one of the most consumed products in the world, and therefore essential for a healthy, complete and balanced diet. In Portugal, despite being an integral part of population’s eating habits, its intake has declined in recent years due to changes in consumption patterns. In a time when consumers are increasingly demanding, looking for convenient, fresh and quality products, bread has been forced to evolve. Presenting a variety of shapes and formats in a way that captivates these consumers, however, bread evolution is strongly influenced by parameters such as freshness, color and texture, being freshness a complex and very difficult parameter to describe and evaluate having into account the variety of breads that exist. Concluding, the main objective of this project was to develop a trained panel as a tool to evaluate the characteristics of bread considered traditional by the company and, in this way, finding points that can be improved by improving the quality of the bread in question. Thus, combining the growing emphasis that sensorial analysis has received in recent years, to the optimization of a traditional product. In this work the different phases for the constitution of a panel of trained tasters are described, as well as their selection and training according to the standards of the sensorial analysis.

A number of recent research studies have investigated the performance of panel zones in seismic-resistant steel Special Moment Resisting Frames (SMF). These recent studies investigated various options for attaching doubler plates to the column at beam-column joints in SMF for purpose of increasing the shear strength of the panel zone. This previous work was primarily focused on doubler plates that extend beyond the top and bottom of the attached beams, and considered cases both with and without continuity plates. As an extension to this previous research, this thesis explores the situation when a doubler plate is fitted between the continuity plates. The objective of this research was to evaluate various options for welding fitted doubler plates to the column and continuity plates through the use of finite element analysis, and to provide recommendations for design. The development and validation of the finite element model are described, along with the results of an extensive series of parametric studies on various panel zone configurations and attachment details for fitted doubler plates. Based on the results of these analyses, recommendations are provided for design of welds used for attaching fitted doubler plates in the panel zone of SMF systems.
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