Light Detection and Ranging (Lidar) is a kind of active sensor that emits a laser pulse and primarily measures the time of flight of the returning pulse and uses it to construct a 3D point cloud of the scene around the lidar sensor. The constructed point cloud is an essential asset for the control of autonomous vehicles, and especially today, an essential basis for the training of autonomous vehicle control models. However, it remains time-consuming, high-risk and expensive to acquire the amounts of data necessary to train the rather complex modern control models. As such, generating the point cloud through simulations becomes a natural solution. Yet, many lidar simulations today produce ideal point clouds, corrected only by random noise, without considering the physical reasons behind the imperfections visible in real lidar point clouds. The aim of this study was to investigate real-time simulation models for disturbances that may cause imperfections in lidar data. From a base investigation of lidar, disturbances were found, models were investigated and finally a real-time implementation of Atmospheric Effects and attenuation from Beam Divergence was evaluated. It was found that the implemented models could produce physically accurate lidar point placement while keeping the computational time low enough for real-time evaluation. However, to achieve correct separation of target hit rates under Atmospheric Effects, as high as 34% of the points had to be dropped. Additionally, the intensity of the return points could not be properly verified. From these results it can be concluded that, with additional verification and adjustment, the presented models can achieve good results for evaluation in real-time. The results of this study thus serve as a support for future developments of realistic real-time lidar simulations, for use in development of autonomous vehicle control models and implementation of digital twins.

Cette thèse se situe dans le cadre d'un processus d'aide à la décision multicritère et multi-acteurs. Elle porte sur la gestion de certains aspects de l'incertitude inhérente à l'évaluation multicritère dans un tel processus. Nous proposons à cet égard une modélisation et une formalisation mathématique de ce processus via une représentation possibiliste des évaluations. Nous avons également proposé de caractériser les distributions de possibilité relatives aux évaluations des différents critères par un ensemble d'indicateurs de description tels que l'imprécision, la divergence, etc., permettant ainsi une interprétation quantitative plus aisée pour le décideur. Nous avons considéré des opérateurs d'agrégation de la famille de l'intégrale de Choquet pour propager les distributions d'évaluations de critère ainsi que les indicateurs de description de distribution, en raison de leur capacité à prendre en compte des interactions entre les critères tout en gardant un caractère de moyenne “généralisée” aisément compréhensible par le décideur. Concernant la propagation des indicateurs, nous avons établi deux théorèmes clés, l'un portant sur l'union des valeurs supérieures et inférieures de l'intervalle moyen d'une distribution de possibilité et l'autre sur l'imprécision moyenne d'une distribution de possibilité la définissant comme la somme des imprécisions moyennes de distributions partielles adjacentes dont elle est l'union. Par ailleurs, Le concept d'explication de la décision a particulièrement constitué le noyau de notre modèle de processus d'aide à la décision. Ainsi à partir des théorèmes établis, nous avons proposé des fonctionnalités explicatives basées sur une quantification de la contribution d'indicateurs décisionnels des évaluations de critères à l'évaluation globale. Nous avons ainsi montré que chaque indicateur relatif à la distribution de l'évaluation globale s'écrit simplement comme une somme pondérée de contributions de critères. Sur le plan applicatif, nous nous sommes intéressés à la formalisation du processus de gestion de mesures de satisfaction de clients dans le contexte de la e-recommandation pour le e-commerce. Nous avons présenté une méthode d'évaluation multicritère des sites de e-commerce par une communauté d'internautes qui permet à la fois de prendre en compte l'importance relative des critères d'évaluation et les interactions entre ceux-ci, mais aussi de gérer différents aspects de l'incertitude inhérents à ce processus d'évaluation. Nous avons développé un prototype logiciel servant de support d'aide à la décision. Cet outil labellisé “Feedback Based Recommendation System” (FBRS) permet de fournir aux managers d'un site de e-commerce, en particulier les équipes marketing et benchmarking, des éléments qui leur permettent de comprendre les scores qui ont été attribués à leur site lors de l'évaluation par les clients. Nous avons montré comment il est alors possible d'identifier les critères les plus influents dans cette évaluation et comment utiliser cette analyse de contributions à des fins de suivi et de management des performances par les responsables marketing et benchmarking. Ces fonctionnalités sont ainsi une base de travail pour ces derniers pour améliorer les stratégies existantes.

In this thesis, we study statistical inference for entropy, divergence, and related functionals of one or two probability distributions. Asymptotic properties of particular nonparametric estimators of such functionals are investigated. We consider estimation from both independent and dependent observations. The thesis consists of an introductory survey of the subject and some related theory and four papers (A-D). In Paper A, we consider a general class of entropy-type functionals which includes, for example, integer order Rényi entropy and certain Bregman divergences. We propose U-statistic estimators of these functionals based on the coincident or epsilon-close vector observations in the corresponding independent and identically distributed samples. We prove some asymptotic properties of the estimators such as consistency and asymptotic normality. Applications of the obtained results related to entropy maximizing distributions, stochastic databases, and image matching are discussed. In Paper B, we provide some important generalizations of the results for continuous distributions in Paper A. The consistency of the estimators is obtained under weaker density assumptions. Moreover, we introduce a class of functionals of quadratic order, including both entropy and divergence, and prove normal limit results for the corresponding estimators which are valid even for densities of low smoothness. The asymptotic properties of a divergence-based two-sample test are also derived. In Paper C, we consider estimation of the quadratic Rényi entropy and some related functionals for the marginal distribution of a stationary m-dependent sequence. We investigate asymptotic properties of the U-statistic estimators for these functionals introduced in Papers A and B when they are based on a sample from such a sequence. We prove consistency, asymptotic normality, and Poisson convergence under mild assumptions for the stationary m-dependent sequence. Applications of the results to time-series databases and entropy-based testing for dependent samples are discussed. In Paper D, we further develop the approach for estimation of quadratic functionals with m-dependent observations introduced in Paper C. We consider quadratic functionals for one or two distributions. The consistency and rate of convergence of the corresponding U-statistic estimators are obtained under weak conditions on the stationary m-dependent sequences. Additionally, we propose estimators based on incomplete U-statistics and show their consistency properties under more general assumptions.

When calculating scattering amplitudes in gauge and gravitational theories one encounters infrared (IR) divergences associated with massless fields. These are known to be artifacts of constructing a quantum field theory starting with free fields, and the assumption that in the asymptotic limit (i.e. well before and after a scattering event) the incoming and outgoing states are non-interacting. In 1937, Bloch and Nordsieck provided a technical procedure eliminating the IR divergences in the cross-sections. However, this did not address the source of the problem: A detailed analysis reveals that, in quantum electrodynamics (QED) and in perturbative quantum gravity (PQG), the interactions cannot be ignored even in the asymptotic limit. This is due to the infinite range of the massless force-carrying bosons. By taking these asymptotic interactions into account, one can find a picture changing operator that transforms the free Fock states into asymptotically interacting Faddeev- Kulish (FK) states. These FK states are charged (massive) particles surrounded by a “cloud” of soft photons (gravitons) and will render all scattering processes infrared finite already at an S-matrix level. Recently it has been found that the FK states are closely related to asymptotic symmetries. In the case of QED the FK states are eigenstates of the large gauge transformations – U(1) transformations with a non-vanishing transformation parameter at infinity. For PQG the FK states are eigenstates of the Bondi-Metzner-Sachs (BMS) transformations – the asymptotic symmetry group of an asymptotically flat spacetime. It also appears that the FK states are related the Wilson lines in the Mandelstam quantization scheme. This would allow one to obtain the physical FK states through geometrical or symmetry arguments. We attempt to clarify this relation and present a derivation of the FK states in PQG from the gravitational Wilson line in the eikonal approximation, a result that is novel to this thesis.

Cross-boundary movements of energy and material are ubiquitous. Freshwater ecosystems receive nutrients, dissolved, and particulate organic matter from adjacent terrestrial ecosystems, whereas terrestrial ecosystems mainly receive prey organisms and detritus deposited by physical processes such as floods from freshwater ecosystems. Within lakes, fish are considered as integrators between habitats due to their high mobility, although they often occupy either near-shore littoral or open-water pelagic habitats and develop habitat-specific morphologies. Such intra-population divergence in morphological traits might limit the use of multiple habitats. In this thesis, I first focused on quantity and quality of reciprocal fluxes of particulate organic matter between freshwater and terrestrial ecosystems and responses of recipient consumers. Freshwater ecosystems generally received higher amounts of externally-produced resources than terrestrial ecosystems. Despite this discrepancy, aquatic and terrestrial consumer responses were similar, likely due to the differences in resource quality. Second, I investigated the potential of particulate organic carbon (POC) supporting benthic food webs in lakes; a pathway that has largely been neglected in previous studies. I found that POC can substantially subsidize the benthic food web and that the effects on the benthic food web were transferred to the pelagic habitat, thus emphasizing the importance of benthic pathways for pelagic production. Third, I examined how water transparency can affect intra-population divergence in perch (Perca fluviatilis). I observed that increased water transparency can considerably increase morphological divergence between littoral and pelagic populations likely due to its effects on foraging. Finally, I investigated the effects of such intra-population divergence on littoral-pelagic food web coupling. I found that low morphological divergence corresponded with high overlap in resource use, whereas strong morphological divergence resulted in low overlap in resource use. Here littoral populations mainly utilized littoral resources and pelagic populations primarily utilized pelagic resources, indicating that habitat coupling might be strongly limited when intra-population divergence is high. In conclusion, although different ecosystems seem separated by distinct physical boundaries, these boundaries are often crossed. However, the development of habitat-specific adaptive traits might limit movement between apparently contiguous habitats.

The theory of economic growth predicts that poorer regions will eventually converge towards the income level of the wealthier regions (Barro & Sala-i-Martin, 2004). The aim of this Bachelor thesis is to establish if absolute convergence in Gross Regional Product (GRP) growth rates exists across LA-regions in Sweden during the period 1994-2004. The variables used in the model of absolute convergence are; the level of initial GRP per capita in the year 1994 and the growth rate of GRP per capita. The authors of this thesis find support of absolute convergence among Swedish LA-regions of 1.67 percent per year. Convergence estimations are also performed for high-, mid-, and low-performing groups of regions in respect to their income level per capita. The low-performing group of regions is in fact converging faster towards the income level of the wealthier regions in Sweden than the mid- and high-performing group. Alternative measurement of convergence is the so called sigma-convergence. The authors find that it only holds for the group of high-performing regions. However, this measurement cannot be considered reliable, as the existence of absolute convergence is necessary for sigma-convergence, but it is not sufficient. / Ekonomisk tillväxtteori förutspår att fattigare regioner med tiden kommer att konvergera mot samma inkomst nivå som rikare regioner har (Barro & Sala-i-Martin, 2004). Syftet med denna Kandidatuppsats är undersöka ifall det förekommer betingad konvergenstillväxt av Brutto Regional Produkt (BRP) nivåer mellan svenska LA-regioner under perioden 1994-2004. Variablerna som används i modellen för betingad konvergens är den ursprungliga nivån av BRP per capita under år 1994, och tillväxtnivån av BRP per capita under perioden 1994-2004. Författarna av denna uppsats har funnit stöd för betingad konvergens bland svenska LA-regioner med en konvergenstakt på 1,67 procent per år. En estimering av konvergens är därtill utförd för hög-, mellan- och lågpresterande grupper av regioner med respekt till deras inkomstnivå per capita. Den lågpresterande gruppen har en snabbare konvergeringstakt mot den inkomstnivå de rikare regionerna i Sverige har, än vad de mellan- och högpresterande grupperna. Ett alternativt mått på konvergens är den så kallade sigma-konvergensen. Författarna finner att detta mått endast håller för gruppen av högpresterande regioner. Emellertid kan inte detta mått räknas som tillförlitligt, då förekomsten av betingad konvergens är nödvändigt för sigma-konvergens, men det är inte tillräckligt.

La tesi que teniu a les mans recull quatre treballs amb un objectiu comú; determinar si els patògens (virus, bacteris, paràsits.) han exercit pressions selectives sobre els genomes dels seus hostes (com per exemple els humans).Sabent que la detecció de l'empremta de la selecció permet identificar aquelles regions del genoma que han estat rellevants al llarg de l'evolució d'una espècie, ja que a nivell local és la variació funcional qui acaba essent objecte de la selecció, ens hem disposat a estudiar els possibles senyals de selecció en gens relacionats amb la interacció hoste-patògen. En concret, hem analitzat gens que codifiquen per: a) components del sistema immunitari innat i, b) enzims de glicosilació, la majoria dels quals s'inclouen en quatre de les principals rutes biosintètiques de glicans, en diferents poblacions humanes.Com a conclusió principal; ambdós conjunts de gens mostren clars senyals de selecció. A més hem vist que segons el context biològic on és troben certs gens és veuen més afectats per l'acció de la selecció natural. / The present thesis includes four studies with a common objective: determining whether pathogens (virus, bacteria, parasites.) have exerted selective pressures on the genome of their hosts (for example, humans).Detecting signatures of positive selection is a useful tool to identify functionally relevant genomic regions since selection locally shapes the functional variation. Based on this premise, we have studied the possible signatures of selection in genes related to host-pathogen interactions. Specifically, we have analyzed those genes encoding: a) components of the innate immunity response; and ii) glycosylation enzymes most of them involved in four major glycan biosynthesis pathways, in different human populations.The main conclusion obtained from these studies is that both studied gene categories show clear signatures of selection. Moreover, we have determined that according to their biological context certain genes are more prone to the action of selection.

The linear instability of laterally diverging/converging flows is an important aspect towards understanding the laminar-transition process in many viscous flows. In this work the linear instability of constant pressure laterally diverging/converging flow has been investigated. The laminar velocity field for laterally diverging/converging flows, under the source/sink approximation, has been reduced to two-dimensional flows. This reduction is alternative to the Mangier transformation used earlier. For a constant pressure laterally strained flow, the laminar velocity is found to be governed by the Blasius equation for flow over a flat plate. The non-parallel linear instability of constant pressure laterally strained flows has been examined. The instability equation is found to be same as that for the Blasius flow. This implies that the stability is same as that for the Blasius flow. A lateral divergence/convergence is shown to alter the Reynolds number from that in a two-dimensional flow. The instability of a laterally converging/diverging flow thus can be obtained from the available results for the Blasius flow by scaling the Reynolds numbers. This leads to the result that while a diverging flow is more unstable than the Blasius flow, a converging flow is more stable. Some additional relevant results are also presented.

<p>The theory of economic growth predicts that poorer regions will eventually converge towards the income level of the wealthier regions (Barro & Sala-i-Martin, 2004). The aim of this Bachelor thesis is to establish if absolute convergence in Gross Regional Product (GRP) growth rates exists across LA-regions in Sweden during the period 1994-2004. The variables used in the model of absolute convergence are; the level of initial GRP per capita in the year 1994 and the growth rate of GRP per capita. The authors of this thesis find support of absolute convergence among Swedish LA-regions of 1.67 percent per year. Convergence estimations are also performed for high-, mid-, and low-performing groups of regions in respect to their income level per capita. The low-performing group of regions is in fact converging faster towards the income level of the wealthier regions in Sweden than the mid- and high-performing group. Alternative measurement of convergence is the so called sigma-convergence. The authors find that it only holds for the group of high-performing regions. However, this measurement cannot be considered reliable, as the existence of absolute convergence is necessary for sigma-convergence, but it is not sufficient.</p> / <p>Ekonomisk tillväxtteori förutspår att fattigare regioner med tiden kommer att konvergera mot samma inkomst nivå som rikare regioner har (Barro & Sala-i-Martin, 2004). Syftet med denna Kandidatuppsats är undersöka ifall det förekommer betingad konvergenstillväxt av Brutto Regional Produkt (BRP) nivåer mellan svenska LA-regioner under perioden 1994-2004. Variablerna som används i modellen för betingad konvergens är den ursprungliga nivån av BRP per capita under år 1994, och tillväxtnivån av BRP per capita under perioden 1994-2004. Författarna av denna uppsats har funnit stöd för betingad konvergens bland svenska LA-regioner med en konvergenstakt på 1,67 procent per år. En estimering av konvergens är därtill utförd för hög-, mellan- och lågpresterande grupper av regioner med respekt till deras inkomstnivå per capita. Den lågpresterande gruppen har en snabbare konvergeringstakt mot den inkomstnivå de rikare regionerna i Sverige har, än vad de mellan- och högpresterande grupperna. Ett alternativt mått på konvergens är den så kallade sigma-konvergensen. Författarna finner att detta mått endast håller för gruppen av högpresterande regioner. Emellertid kan inte detta mått räknas som tillförlitligt, då förekomsten av betingad konvergens är nödvändigt för sigma-konvergens, men det är inte tillräckligt.</p>

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