My dissertation is an advocacy of the idea that if aid proved to be ineffective, it is partly because of the donor and not only the recipient as it is usually argued. The thesis contributes to the theoretical and empirical literature on aid effectiveness and explores the ability of aid to achieve its goals in the presence of both incentives and informational problems. <p>The thesis consists of three essays dealing with a particular aspect of donor policies that may impact the effectiveness of aid: i) the drivers of aid allocation among recipient countries, ii) ex-post conditionality and the role of reputation in inducing compliance with aid contracts; iii) and finally, the optimal choice of aid modalities.<p>The first chapter investigates the drivers of U.S. aid policy. <p><p>I find considerable evidence that the pattern of aid is dictated as much by political and strategic considerations, as by the economic needs and merit of the recipients. Most importantly, inertia seems to impact heavily the aid allocation process. Any of these motivations, when excessive, would lead to a time inconsistency situation where the donor is not credible in his conditionality. With such an impact on aid allocation, the question arises on the effectiveness of conditioning aid provision on political, social, or economic reforms. This is precisely the scope of chapter 2.<p><p>The second chapter investigates the conditions under which reputation can serve as commitment device in order to induce donors of development aid to enforce aid contracts and recipients to comply with such contracts. The idea is that the success of conditionality rests solely on the availability of a commitment technology that ties the hands of the donor. Reputation concerns could create the required incentives and overcome the altruism effect on the donor side.<p><p>Notwithstanding that incentive creation must not be driven by the volume of aid only, but also by the way it is channelled, i.e. aid modality. This is particularly relevant for recipients with certain characteristics. Depending on the preference alignment of the donor and the recipient, the information structure in place, the optimal aid modality can change. The characteristics of the optimal aid package are investigated in chapter 3. Optimality imposes a mix of fixed project and financial transfer to recipient countries. The transfer can be negative for countries exhibiting a high willingness or ability to redistribute to the poor. This is interpreted as a contribution to the financing of the infrastructure project. The extent of the project (large or small size) is determined by the interest of government for the poor in the recipient country.<p> / Doctorat en Sciences économiques et de gestion / info:eu-repo/semantics/nonPublished

The introduction of new information technology (IT) in an organisation is one way of changing the conditions for how tasks and work processes can be designed and performed, as well as how people in the organisation interact with each other. Today, many Swedish workers rely completely on IT to be able to perform their jobs, while experiencing a combination of continuous and intermittent IT-related changes that affect this ability. The introduction of new or updated IT systems in an organisation is an example of what is referred to as an IT-related change process in this thesis. Because IT has become such an integral part of modern organisations, many change processes in organisations are simultaneously enabled and constrained by the IT systems involved in a change process. In this thesis, I introduce the concept of inertia in sociotechnical systems to analyse IT-related change processes in organisations, and how achieving the goals of these processes is complicated by organisational, social, and physical aspects in addition to technology. The context of this thesis is the Swedish public sector domains of health-care and higher education, and the result of research studies and experiences from four action research projects in these settings. The contribution of this thesis adds to the contributions of the included papers through the definition of inertia in sociotechnical systems and its subsequent application. The thesis shows that the concept of inertia in sociotechnical systems can be used to understand IT-related change processes as changes to the characteristics of a sociotechnical system, and, in the context of organisations, how these processes affect and are affected by an organisation’s characteristics. This is illustrated in the thesis through the application of the concept on examples of IT-related change processes from the included papers and research projects. In addition, the thesis shows that the use of vision seminar methods can benefit Swedish organisations, since new IT is often introduced without clearly defined, expressed, understood, and accepted goals.

Les mousses métalliques ont connu un essor important durant les dernières décennies. Leur capacité à supporter de très larges niveaux de déformation tout en transmettant de faibles contraintes les rend particulièrement adaptés à des solutions d'absorption d'énergie ou de protection contre des sollicitations intenses.Le comportement dynamique de ce type de matériau peut être influencé par les effets inertiels au niveau des parois ou des ligaments constituant son squelette (micro-inertie). Un modèle de comportement à base micromécanique a été développé pour prendre en compte les effets micro-inertiels sur le comportement macroscopique de mousses à porosités fermées. Le modèle proposé repose sur la procédure d'homogénéisation dynamique introduite par Molinari et Mercier (2001). Par cette approche, les effets micro-inertiels apparaissent sous la forme d'un terme supplémentaire dans le tenseur des contraintes, appelé contrainte dynamique. À partir de comparaisons avec des données extraites de la littérature, il est ainsi démontré qu'inclure les effets micro-inertiels permet d'obtenir une meilleure description de la réponse des mousses sous choc.L'influence d'une épaisseur de mousse localisée entre un explosif et une enveloppe cylindrique a ensuite été étudiée en suivant deux approches. La première, qui s'appuie sur les travaux de Gurney (1943), repose sur des considérations énergétiques. La seconde méthode permet d'aboutir à une description plus détaillée des tailles et vitesses de fragments. Elle repose sur la combinaison d'un modèle éléments finis pour décrire la propagation de l'onde de choc dans la mousse et l'expansion de l'enveloppe et d'un modèle de fragmentation de type Mott (1947). / Metallic foams have known a growing interest in the last decades. Their ability to undergo very large strains while transmitting only reasonable stress levels makes them particularly suitable for energy absorption applications and protection against intense solicitations. The dynamic behavior of metal foams is linked to inertial effects appearing at the walls and ligaments of the material microstructure (micro-inertia). A constitutive model has been developed to take micro-inertial effects into account when describing the macroscopic behavior of closed-cell foams submitted to dynamic loadings. The proposed approach was developed using the dynamic homogenization procedure introduced by Molinari and Mercier (2001). Within this framework, micro-inertial effects appear as an additional stress term, called dynamic stress. Comparisons with data from literature have showed that including micro-inertia effects allows one to achieve a better description of the foam response under shock loading.The influence of a foam layer placed between an explosive and a cylindrical casing has been investigated by following two approaches. The first one is based on energetic considerations, following the work of Gurney (1943). The second method allows one to obtain a more detailed description of fragment sizes and velocities. It relies on the combined use of a finite element model and a description of the shell fragmentation based on the work of Mott (1947).

L'endommagement des matériaux ductiles est un processus impliquant trois étapes : la nucléation, la croissance et la coalescence de vides. La phase de croissance des vides a été largement étudiée dans la littérature. Il a été montré que, durant cette étape, la forme des vides joue un rôle fondamental sur le comportement macroscopique du matériau. Dans le cas de sollicitations dynamiques, les effets micro inertiels, qui résultent des accélérations subies par la matrice au voisinage du vide, influent eux aussi fortement sur la croissance des vides. Cependant, les travaux intégrant simultanément ces deux contributions (effets inertiels et forme) sont très rares. L'objectif de ce travail est de proposer un modèle de comportement pour les matériaux poreux qui prend en compte la forme des vides et les effets micro inertiels. Dans une première partie, un volume élémentaire représentatif défini par deux ellipsoïdes allongés confocaux est utilisé pour représenter le matériau poreux. La matrice est rigide viscoplastique. En se basant sur les travaux de Molinari et Mercier (2001), la contrainte macroscopique se décompose en une partie statique et une partie dynamique. La contrainte statique est décrite par le modèle de Gologanu et al. (1997). La contrainte dynamique est obtenue en adoptant le champ de vitesse de Gologanu et al. (1993). Avec cette modélisation, il est montré que la contrainte dynamique est liée de façon quadratique au tenseur des vitesses des déformations et de façon linéaire à sa dérivée par rapport au temps. Le modèle fait l'objet d'une validation sur la base de comparaisons avec des résultats de calculs par éléments finis. Différentes forme de vides et valeurs de la porosité ont été considérées. Dans une seconde partie, le cas de matériaux contenant des vides aplatis est abordé ; le volume élémentaire représentatif est défini par deux ellipsoïdes confocaux aplatis. La contrainte statique est toujours décrite par le modèle de Gologanu et al. (1997). La contrainte dynamique est obtenue en adoptant le champ de vitesse de Gologanu et al. (1994). La procédure de validation est identique à celle mise en œuvre dans le cas des vides allongés. Une bonne adéquation entre les résultats du modèle et les résultats de calculs par éléments finis est retrouvée. L'utilisation des surfaces d'écoulement permet de mettre en lumière les effets de la forme des vides sur le comportement du matériau poreux sous chargement dynamique. En fonction du chargement appliqué, certaines géométries de vide favorisent la déformation du matériau. Le cas particulier du vide sphérique est étudié comme limite des deux modèles. La continuité des deux modèles est démontrée. L'évolution de la porosité et de la forme des vides dans un matériau poreux sous chargement dynamique est analysée. Des comparaisons avec des résultats de simulations par éléments finis sont proposées. L'influence de la triaxialité et de la vitesse du chargement sur le comportement dynamique du matériau poreux est étudiée, ainsi que celle de la forme initiale du vide. Au final, il est démontré que le modèle développé dans cette thèse permet de retrouver les tendances fournies par les calculs éléments finis / The ductile fracture mechanism involves three stages: void nucleation, void growth and void coalescence. Under dynamic loading conditions, void growth is strongly affected by microinertia effects resulting from the local acceleration of the matrix material in the vicinity of the void. Several works devoted to quasi-static conditions also show that void shape has a strong impact on the behavior of porous ductile materials. However, there exist only few works considering the combined effect of these two contributions. In the present work, we propose an original, multi-scale constitutive model of porous materials, taking into account void shape and micro-inertia effects. In a first step, a representative volume element defined by two confocal prolate spheroids is used to represent the porous material. The matrix behavior is assumed to be rigid-viscoplastic. Based on the work of Molinari and Mercier (2001), the macroscopic stress is the sum of a static and a dynamic part. The static contribution is described by the Gologanu et al. model (1997). The dynamic stress is derived by choosing the trial velocity field proposed by Gologanu et al. (1993). With the present modeling, a link is established between the macroscopic dynamic stress, on the one hand and, the macroscopic strain rate tensor and its time derivative on the other hand. To validate the proposed model, finite element computations have been performed for different void geometries and void volume fractions. The influence of micro-inertia on the macroscopic flow surface is analyzed and a good agreement between modeling and simulations is observed. In a second step, a representative volume element defined by two confocal oblate spheroids is used to represent the porous material. For this configuration, the static contribution is also described by using the Gologanu et al. model (1997), while the derivation of the dynamic stress is based on the trial velocity field proposed by Gologanu et al. (1994). As for the prolate case, a good agreement is retrieved between model predictions and results of finite element computations. The spherical void configuration is investigated as the limit case for the oblate and prolate models. The continuity between the two models is established. Finally, the proposed models are combined to investigate the porosity and void shape evolutions in a porous solid under dynamic loadings. A parametric study has been performed by varying the stress triaxiality, the initial void shape and the loading rate. Significant void shape variations are observed for low triaxiality loadings. With the present modeling, the void can evolve from prolate to oblate shapes (and the reverse). Model predictions are compared to finite element computations

Les objectifs de la présente thèse sont l'analyse des mécanismes de couplage surface-atmosphère contrôlant la température moyenne de surface et son cycle diurne dans les régions sèches, humides et de transition.Nous montrons le rôle clé de l'inertie thermique sur la température de surface dans les régions sèches. La sensibilité à l'inertie thermique de la température de nuit est plus élevée que la sensibilité de la température de jour, impactant la température moyenne journalière. Nous montrons que cet effet est directement lié à l'instabilité de la couche limite, plus forte le jour que la nuit. Nous mettons également en lumière le double rôle du forçage solaire : Le premier est d'être la source du contraste diurne de la couche limite, à l'origine de la dissymétrie de réponse de la température à l'inertie thermique, le second est d'atténuer cet effet, puisque la forte dissymétrie du forçage solaire favorise la sensibilité de la température de jour par rapport à la nuit.Dans les régions humides, nous constatons que la sensibilité de la température de surface à l'inertie thermique est très faible. Ceci est dû aux fortes valeurs du flux latent qui contrôle la température de surface. Néanmoins, nous signalons que l'inertie thermique peut impacter le bilan d'eau à la surface, comme dans la région de la mousson indienne par exemple.Dans les régions de transition, nous montrons que la relation entre la température et l'humidité de surface est atténuée de 20 à 50 \% environ, du fait de la dépendance de l'inertie thermique à l'humidité de surface. Nous suggérons ainsi d'intégrer l'effet de l'humidité sur l'inertie thermique en plus de son effet sur l'évaporation. / The main objectives of this study are to analyze the surface-atmosphere coupling mechanisms controlling the mean temperature and its diurnal cycle in the dry, humid and transitional zones. We show that thermal inertia plays a key role on the surface temperature in dry regions. The sensitivity of surface temperature to thermal inertia is high during the night but low during the day, impacting the mean surface temperature. We demonstrate that this effect is directly related to the instability of the planetary boundary layer, which is higher during the day compared to the night.Moreover, we emphasize the dual role of the solar forcing. The first one is to be the source of the diurnal contrast of the planetary boundary layer, which is the origin of the diurnal asymmetry of the surface temperature response to thermal inertia. The second one is to attenuate this effect, since the high asymmetry of the solar forcing foster the sensitivity of the day temperature compared to the night. In humid regions, we notice that the sensitivity of the surface temperature to thermal inertia is weak. This is due to the high values of the latent heat flux which controls the surface temperature. Nevertheless, we should point out that the thermal inertia may have an impact on the water budget at the surface, as it is the case in the Indian Monsoon region. In the transitional regions, we show that the relation between surface temperature and soil moisture is attenuated by about 20 to 50 % because of the dependency of the thermal inertia to soil water content. Hence, we suggest to integrated the effect of soil moisture on the thermal inertia in addition to its effect on evaporation.

Les instruments politiques sur les émissions de véhicules passagers visent à réduire les externalités négatives sur l'environnement causées par l'usage des véhicules. Des réglementations sur les émissions de CO2 ont été mises en place en Europe, aux États-Unis, en Chine et ailleurs. La cible réglementaire basée sur la moyenne des émissions des véhicules vendus par un constructeur devient plus contraignante au fil du temps. Cette thèse analyse comment les constructeurs automobiles anticipent et préparent leurs futurs portefeuilles de technologies afin de respecter les futurs objectifs politiques. Pour conduire cette analyse, cette thèse développe un modèle d'optimisation des choix technologiques sous la contrainte de diffusion technologique.Avec ce cadre de modélisation basé sur la limitation de la vitesse à laquelle une technologie peut se diffuser dans un marché, cette thèse étudie trois questions politiques. Dans un premier temps, nous analysons comment le type d'anticipation du futur peut modifier les choix technologiques faits à court et à long termes. Nous montrons qu'une anticipation du futur focalisée sur les objectifs de court terme peut empêcher l'atteinte de la cible à long terme. Respecter la cible à court terme n'est une condition ni nécessaire ni suffisante pour permettre le niveau d'émissions requis par la cible à long terme. De plus si l'anticipation du futur n'est pas parfaite, les choix technologiques vont être verrouillés dans des technologies à faible potentiel d'abattement créant ainsi une dépendance au sentier qui limite l'abattement potentiel à long terme.Dans un deuxième temps, nous nous intéressons à évaluer quantitativement comment l'indexation sur la masse des véhicules de la réglementation CO2 change les critères optimaux de choix. Nous montrons qu'il n'existe pas de différence significative dans le coût social de la mobilité entre les deux mécanismes de réglementation CO2 avec et sans indexation sur la masse pour une même cible d'émissions. Cependant les choix technologiques entre ces mécanismes sont différents, la réglementation CO2 indexée à la masse ne développe en aucun cas les technologies d'allègement.Dans un troisième temps, nous étudions comment les choix technologiques changent quand des politiques à objectifs multiples se superposent. Nous centrons notre analyse sur deux externalités associées à la mobilité: les émissions CO2 et la pollution de l'air locale. Nous montrons trois types d'impacts de la superposition de politiques. Premièrement, une politique technologiquement spécifique tel que le Mandat de Véhicule à Zéro Émission en combinaison avec la réglementation CO2 provoque le développement de technologies vertes coûteuses et empêche les technologies sales et peu coûteuses de disparaître. Dans le cas de l'application de la réglementation CO2 seule nous n'observons pas ce comportement. Deuxièmement, la superposition de politiques peut mener à un coût élevé quand les technologies adaptées à chacune des politiques sont très différentes. Troisièmement, nous trouvons un effet ambigu de la superposition de politiques relative à l'application d'une politique seule sur la performance environnementale. / Policy instruments on passenger vehicle emissions aim at reducing negative environmental externalities from vehicles use. To regulate CO2 emissions, fuel economy standards have been put in place in Europe and in the US, among others. These standards are made more stringent over time. This thesis analyzes how automotive firms anticipate and prepare their future technology portfolio to comply with expected future standards. To do so, we develop a model of optimal technology choice that captures technology diffusion constraints.With this framework, this thesis investigates three policy questions. First, we ask how the form of anticipation can affect near- and long-term technology choices. We find that focusing solely on near-term objectives can lead to failure to comply with a long-term target. In fact, meeting the near-term target is not a necessary nor a sufficient condition to satisfy long-term compliance. Moreover, when there is partial anticipation, as in a myopic view of the future, technology choices will be stuck with low abatement technologies creating a path dependency that limits long-term abatement potential.Second, we ask how much indexing fuel economy standard to mass (as in Europe or China) changes the optimal technology. We show that, for the same emission target, there is no significant difference in the social cost of mobility for an average vehicle with and without mass index. Thus a heavier vehicle fleet has the same cost than a lighter one. However, the technology choices are different, and mass indexed fuel economy standards lead to sidestepping lightweight technologies despite being cost effective from a CO2 emissions abatement point of view.Third, we ask how technology choices change when policies with multiple objectives overlap. We focus on two externalities associated with mobility: CO2 emissions and local air pollution. We show three type of effects of overlapping policies. First, a technology specific policy such as the Zero Emission Vehicle Mandate in combination with a fuel economy standard induces carmakers to develop more expensive green technologies and prevents cheap, dirty technologies from disappearing compared to the case of a fuel economy standard alone. Second, the combination of policies can lead to very high costs when technologies adapted to each policy are very different. Third, we find an ambiguous effect of overlapping policies relative to single-objective policy in terms of emissions performance.

There is a trend in Sweden towards increasing the electricity production from renewable energy sources in the electric grid. The increased share of renewables could be seen as essential for Sweden to be able to meet the obligated climate goals. Integration of renewables will enable Sweden to be a progressive part in reducing greenhouse gases and decreasing the global warming. However, one issue with renewable energy sources is the inverter governed production. This, together with the decommission of larger synchronous generators, results in decreasing the inertia and increasing the instability inthe grid.  This thesis is dedicated to elaborating on frequency stability issues and investigating how Variable Speed Wind Turbines (VSWT) could contribute towards stabilized operation when included in frequency support services.  The study is generated through an extensive research process where focus areas are identified. Questions are purposed and then discussed through interviews with experienced people in the field. Estimated power production series from a wind turbine park (WTP) are applied in a constructed model to study the possibilities appearing when  including VSWTs in frequency support services. The income generated from including VSWTs in different regulation power market services is with the model compared against solely procuring the production capacity on the day ahead market. The studied frequency support services are then compared altogether to generate favorable solutions. The study examines both economic as well as technical features of the inclusion of VSWTs in frequency support services.  Results found in the study were that inclusion of wind turbines for power regulation purposes could be seen as increasingly manageable and needed in the electric grid. The maturity of technical solutions alongwith a transition in the regulation power market could be observed as leading factors. The diversification of regulation abilities and the increasing economic incentives in the regulation power market was also found to be important reasons for including wind turbines in the regulation power market. In the study, it was also found thataggregating the power production from several VSWT could increase the ability to deliver the studied services.  It was concluded that inclusion of VSWT in the frequency containment reserve during disturbed operation for down-regulation purposes as well as the fast frequency reserve was the most promising frequency support products for the inclusion of wind turbines. When including battery energy storages and to a larger part managing the durability demands for the services then the frequency contain reserve for normal operation and the frequency containment reserve for disturbed operation for upregulation purposes could be observed as preferable alternatives. Regulation abilities were concluded as achievable with the use of pitch and torque regulation techniques available in the variable speed wind turbine.

This diploma thesis deals with the simulation of various operating situations in the network with many non-rotating power sources, especially focusing on frequency stability. Non-rotating power source is any source that delivers its power to the grid via power electronics. The first part of the thesis describes power system of the Czech Republic and its future development. In the next section, there is short description of today's most common non-rotating power sources. The third part deals with power regulation of the frequency in the grid. The following part describes the models of electrical circuit created for use in PSCAD simulations. The penultimate part describes simulations performed on a model of the network with many non-rotating power sources, which also includes rotating sources. The last part describes simulations performed on a model of the network that is composed of non-rotating power sources only.

This master's thesis deals with problems connected with measuring vehicle centre of gravity height. The research part summarizes generally known methods of measuring vehicle centre of gravity and moments of inertia. Essential part of this thesis is the design of a device for measuring the centre of gravity height of a road vehicle on a principle of measuring a period of oscillation. The height position of the platform of the device is adjustable through hydraulic cylinders. A stress-strain analysis of the design was executed through a combination of analytical methods and a finite element method. The process of measurement was described and an equation for determination of centre of gravity height was deduced. Error of measurement was estimated based on the knowledge of partial errors of measured values.

The diploma thesis is focused on the research of dynamics of selected heating surfaces behavior. The aim of the thesis is to determine the dynamics of heating and cooling and to determine the effect of these characteristics on energy consumption of the building. The project part deals with the design of a heating solution for a residential building in three variants. An Energetic simulation is made for the designed variants, that compares the consumption of thermal energy during one year. The next simulation research the dynamics of selected large-scale heating surfaces. For each construction, nonstationary models of heating up and cooling were made, which are compared in terms of the thermal inertia.