Texte remanié de--Leiden (Pays-Bas)--Université de Leiden, 2003. / Thèse en anglais avec un résumé et une page de garde en néerlandais. Bibliogr. en fin de chap.

Desde o início da história da aviação, cada nova aeronave é criada para que seja mais econômica, mais rápida, mais leve, melhor do que as que a antecederam. Compreender a evolução tecnológica da aviação é extremamente útil quando se deseja projetar uma nova aeronave. Saviotti (1984) e, posteriormente, Frenken (1997) propuseram um método de análise da evolução tecnológica de aeronaves. Esse método, baseado em conceitos de teoria da informação desenvolvidos por Shannon (1948), especialmente o conceito de entropia estatística, se mostrou bastante eficaz. O método, porém, é essencialmente uma ferramenta de análise, e não de projeto. Baseado em um banco de dados de aeronaves, o método é capaz de determinar em que medida cada uma delas foi influenciada por seus predecessores (o que se denomina "convergência") e, por sua vez, influenciou seus sucessores (o que se denomina "difusão"). Neste trabalho, uma ferramenta de auxílio ao projeto de aeronaves é proposta. Essa ferramenta se baseia no método de entropia estatística. Dadas especificações da aeronave que se deseja projetar, e um banco de dados com informações de diversas aeronaves, é realizada a minimização da entropia do sistema, o que conduz a uma aeronave com alto índice de convergência, ou seja, que tenha absorvido o mais possível da tecnologia de aeronaves existentes. A minimização da entropia é realizada através de um algoritmo genético. O algoritmo foi selecionado devido a sua robustez ao lidar com grandes quantidades de informação, minimizando diversas variáveis independentes simultaneamente mesmo na ausência de uma modelagem física do sistema. Foram realizadas diversas análises para avaliar a eficácia do método da entropia estatística. Em especial, um design criado pelo método foi comparado com três outros projetos com as mesmas especificações, realizados por times distintos de engenheiros utilizando-se de métodos convencionais. Além disso, foi avaliada a gama de especificações na qual o método é eficaz, e os seus limites. Como forma de avaliar mais completamente a qualidade dos resultados produzidos pelo método, estes foram testados, através de uma análise de desempenho das aeronaves obtidas, para avaliar se eram internamente consistentes.

Myndigheter inom transportsektorn, forskare och konsulter använder sig, i olika syften, av godsflödesstatistik. Med hjälp av denna statistik förklaras hur infrastrukturen av exempelvis vägar, terminaler och hamnar används. En brist i den godsflödesstatistik som används av de olika myndigheterna inom transportsektorn är att den inte ger någon information om hur hela transportkedjor av varor ser ut. Syftet med detta arbete har varit att undersöka hur privata företags varuflödesinformation, som härstammar från spårningstekniker, skulle kunna utnyttjas för att komplettera den befintliga godsflödesstatistiken. För att ta reda på hur varuflöden kontrolleras och hur dessa data skulle kunna utnyttjas har tre olika företag intervjuats; två varuägande företag och ett transportföretag. Det visade sig att varuägarna har relativt lite information kring varors transportflöden. Det borde emellertid finnas goda möjligheter att utnyttja den sändningsdata som förs av transportföretagen gällande deras kunders leveranser. I slutet ges även förslag på vidare arbete för att ta reda på hur denna information skulle kunna användas för att sammanställa statistik. / Authorities among the transport sector, researchers and consultants use statistics of goods for different purposes. The infrastructure of how, for example, roads, terminals and ports are utilized can be described using this statistics. The flow of goods statistics lacks information about the entire transport chains for goods. The purpose of this thesis was to examine how the statistics could be complemented using companies’ own information of the flow of goods from tracking techniques. By interviewing three different enterprises; two goods owners and one transport company, it has been examined how flows of goods are controlled at each one of the three case companies. It appeared that the information about the flow of goods among the goods owners is fairly small. However, there should be good opportunities to use delivery data maintained by transport companies. This thesis also proposes examples of further research to find out how this information can be used for compiling statistics.

Marknadsanalys ger en grund för antaganden som bygger på marknadsvärdebedömningen, men mest simplifierat är att beskriva marknadsanalys som, ska jag köpa eller inte köpa? Frågan innefattar många delmoment för att avgöra efterfrågan och få en korrekt prisbildning. Men i studiens innehåll har delmomentet prisstatistik på sålda objekt mest fokus. Prisstatistik på sålda objekt är otroligt viktigt för att kunna få en korrekt prisbildning, däremot enligt Riksbyggen är det ibland utmanade att finna just den statistiken i småorter. Studiens syfte är att undersöka hur Riksbyggen arbetar i småorter med bristfälligt underlag för prisstatistik, samt utreda om det finns metoder för att bemöta osäkerheten som uppstår. Studien utfördes utifrån en kvalitativ metod i form av en semistrukturerad gruppintervju med tre respondenter. Resultatet tydliggör att vid bristfällig prisstatistik framkommer en mängd osäkerheter som leder till att marknadsanalysen blir svårbedömd. Slutsatsen är att det finns metoder för att bemöta olika osäkerheter som presenterades i resultatet. Några exempel är, osäkerhetsintervall är lämplig att använda som en metod att bemöta osäkerheten som uppstår vid användandet av delmarknader och för äldre prisstatistik. Jämföra prisutveckling på villor och bostadsrätter är möjligt och kan användas som ett sätt att fylla ut statistikunderlaget. / Market analysis provides a basis for assumptions driven in the market value assessment, but to describe market analysis as whole, the most simplified way is to describe as, should I buy or build? The question includes several elements to determine demand and receive an accurate price formation. But in the content of this study, price-statistics on sold objects has the sole focus. Price-statistics on sold objects are essential to receive a correct price formation, however according to Riksbyggen, it’s sometimes challenging to find price-statistics in small towns. The purpose of the study is to investigate how Riksbyggen work in small towns with insufficient price statistics and investigate whether there are methods that can respond to the uncertainty that arises. The study was conducted based on a qualitative method in the form of a semi-structured group interview with three respondents. The result clarifies that in the event of deficient price-statistics, several uncertainties arise. Which leads to the market analysis being difficult to assess. The conclusion states that based on the theory contrary to the result, there are methods that can respond to various uncertainties that is presented in the result. Some examples are, uncertainty intervals are suitable as a method to respond to the uncertainty that arises from the use of submarkets but also for old price-statistics. Comparing price development of villas and condominiums is possible and can be used as a method to fill out the statistical data.

Negli ultimi anni le continue esigenze di mercato hanno spinto gli agricoltori a richiedere trattrici sempre più evolute e altamente specializzate al fine di limitare i costi e massimizzare le rese produttive. Per questo motivo i progettisti hanno dovuto sviluppare delle metodologie per definire con precisione il profilo di utilizzo delle macchine, al fine di ridefinire i test per la validazione finale dei componenti delle trattrici. Uno dei componenti più costosi è la trasmissione, in quanto è costituita da diversi automatismi e pertanto, in questa tesi, è stato descritto un piano sperimentale atto all’acquisizione di dati da trattrici utilizzate da clienti, con l’obiettivo di monitorare l’utilizzo delle trasmissioni. In una prima analisi sono state identificate relazioni statistiche del diverso utilizzo delle trasmissioni delle trattrici in funzione dell’area geografica di vendita e della potenza massima del motore. Sono state poi stimate le distribuzioni ed i parametri del tempo di neutro, delle gamme e retromarce, al fine di integrare le limitazioni riscontrate dalle analisi di correlazione cliente sulle trattrici. E’ stato riscontrato che la vita lavorativa di una trattrice è caratterizzata dal utilizzo del neutro e della gamma media per oltre il 75%. Non sono state evidenziate differenze significative tra i valori del 5° percentile della distribuzione del Neutro per l’intero campione rispetto a quelli calcolati per i gruppi, i quali sono stati formati in funzione dei fattori area geografica e intervalli di potenza massima motore. La gamma media, oltre ad essere la gamma più utilizzata, risulta essere influenzata dai fattori presi in esame, in particolare per le trattrici di potenza pari a A kW. / In the lasts years, the continuous demands of agricultural market, have prompted farmers of having more advanced and highly specialized tractors. This in order to limit the costs and maximize the working yields. Designers have, for the previous reasons, developed methods on the definition of machine usage profile, in order to re-define the final validation tests of tractor components. Considering that the most expensive components is the transmission, because it is constituted by various automatic functions, in this thesis it has been described an experimental acquisition data plan from tractors used by customers, to monitor the transmissions. First of all, there were identified statistical relations of the different tractor’s transmissions usage considering sale geographical areas and the maximum engine power. Therefore, there have been estimated distributions and parameters for neutral time, ranges and reverse gears, to supplement the limitations of customers correlation analysis about tractors. It has been verified that the tractor’s life time is characterized by the usage of the neutral and intermediate range for more than 75%. No significant differences were found between the values of the 5° percentile of the neutral gear distribution for the entire sample, compared to those calculated for the groups. These groups were formed considering the geographical area and maximum engine power ranges factors. The intermediate range, besides being the most used, is influenced by the considered factors, in particular for tractors with A kW of maximum engine power.

Diss--Leyden.

Diss--Leyden.

Hensen-Körper sind seit längerem in der Literatur beschrieben, jedoch ist ihre Funktion bis dato nicht hinreichend geklärt. Es wird vermutet, dass Hensen-Körpern nach Schädigung des Innenohres vermehrt in kochleären äußeren Haarzellen vorkommen. Hensen-Körper sind kreisförmige Strukturen, die aus kleinen Vesikeln aufgebaut sind. Diese liegen meist zentral im Zytoplasma der kochleären äußeren Haarzellen mit Kontakt zu den subplasmalemmalen Zisternen, einem an die Plasmamembran grenzenden Membransystem. Ziel dieser Arbeit war es zu klären, ob eine Beziehung zwischen einer Schädigung des Innenohres (chemisch-toxisch oder akustisch) und der Auftretenswahrscheinlichkeit von Hensen- Körpern besteht. Es wurden 1413 Semidünnschnitte des Cortischen Organs von Meerschweinchen lichtmikroskopisch untersucht, nachdem diese mit Salicylsäure, Chinin bzw. mit Breitbandrauschen einer Intensität von 90 bzw. 110 dB SPL behandelt wurden. Als Kontrollgruppe dienten Neugeborene, 4-6 Wochen junge und ca. 11 Wochen alte unbehandelte Tiere. Im Anschluss daran erfolgte eine statistische Auswertung. Hensen-Körper kamen vermehrt in der Gruppe der neugeborenen Meerschweinchen vor, bei älteren Tieren zeigten sich keine signifikanten Vermehrungen. Bei den Meerschweinchen, die Noxen ausgesetzt wurden, kommen sie bei den mit 90 bzw. 110 dB beschallten und den mit Salicylsäure behandelten Tieren vor, sofern in diesen Fällen eine reversible, morphologisch nachweisbare Schädigung in der Zellmembran stattgefunden hatte. Bei irreversiblen Zellschädigungen jedoch kam es nicht zur Ausbildung von Hensen-Körpern. Somit ist zu vermuten, dass Hensen-Körper im Rahmen der Zellregeneration in kochleären äußeren Haarzellen auftreten. Auch bei den chininexponierten Tieren trat eine Vermehrung von Hensen-Körpern auf. Dies ist auf eine elektrophysiologische Veränderungen am Membranpotential der äußeren Haarzellen zurückzuführen. Da Hensen-Körper Calciumspeicher sind, unterstützen sie so die Aufrechterhaltung und Wiederherstellung des Membranpotentials und werden somit im Falle einer Schädigung der äußeren Haarzellen vermehrt gebildet. In den inneren Haarzellen konnten keine Hensen-Körper nachgewiesen werden. Die erarbeiteten Befunde legen nahe, dass Hensen-Körper bei Neugeborenen physiologisch vorhanden sind und bei reversiblen Schädigungen der äußeren Haarzellen im Rahmen der Regeneration vermehrt auftreten. / Hensen bodies are known for a long time, but their function isn`t clear, yet. It´s supposed that after damaging the inner ear, Hensen bodies appear in outer cochlear hair cells. They are flat circular structures, built by small clusters of vesicles. Normally, they are situated in the central cytosol of the cochlear outer hair cells and are associated with a membranous system, called subsurface cisternae. Therefore we tried to show, if there is a correlation between damaging the inner ear by noise or chemical- toxins and the appearance of Hensen bodies. 1413 semi-thin- cuts of the organ of Corti of guinea pigs are microscopically examinated after treating them with salicylic acid, quinine or noise stimulation (90 or 110 dB SPL). These groups are compared with newborn, 4-6 weeks and 11 weeks old guinea pigs. Hensen bodies are more frequent in the newborn group. In the groups, which were treated with salicylic acid, 90 or 110 dB SPL Hensen bodies appeared more often, if there was a reversible damage of the membranous cell-structures. If it was an irreversible damage, there was no increase of Hensen bodies. So it could be assumed, that they are involved in cell regeneration process in outer hair cells. An increase of Hensen bodies was also seen in the quinine exposed guinea pigs. This might be according to electrophysiological changes in the membranes of outer hair cells. There is no evidence that Hensen bodies also appear in inner hair cells.

La présence de dépendance spatiale des prix immobiliers impose aux méthodes d’estimation de prendre en compte cet élément. Les deux approches de la statistique spatiale sont l’économétrie spatiale et la géostatistique. La géostatistique estime directement la matrice de variance-covariance en supposant que la covariance entre les observations dépend inversement de la distance séparant leur localisation. L’économétrie spatiale définit et intègre la matrice d’interaction spatiale dans un modèle de régression hédonique. Si ces deux méthodes sont possibles pour étudier la dépendance spatiale des prix immobiliers dans des contextes variés, il n’existe cependant pas de règles très claires quant au choix de la méthode à sélectionner. Cette thèse procède à un examen détaillé de ces deux approches afin de pouvoir en distinguer les ressemblances et les différences, les avantages et les inconvénients. Des exemples d’application de chaque approche dans une étude immobilière sont présentés. La géostatistique est utilisée pour analyser la stationnarité du variogramme, ainsi que la sensibilité du variogramme aux paramètres de l’estimation hédonique. Le modèle d’économétrie spatiale est utilisé pour tenter d’identifier économétriquement le quartier dominant du marché immobilier d’une ville / Geostatistics and spatial econometrics are two spatial statistical approaches used to deal with spatial dependence. Geostatistics estimates directly the variance-covariance matrix by assuming that the covariance among observations depends inversely on the distance between their locations, called the covariogram. Spatial econometrics defines and integrates the spatial interaction matrix in a hedonic regression model. In real estate, price estimation should take into account these spatial characteristics because property prices are correlated. Hence, these two approaches are commonly used to study the spatial dependence of the real estate prices in many contexts. However, a definite rule in selection these statistic approaches has not been established. This thesis examined these two approaches in order to distinguish the similarities, differences, advantages, and disadvantages of each methodology. Some examples of their applications in a real estate study. The geostatistics is used to analyze the stationarity of the variogram and its sensitivity depending on the parameters added in hedonic estimation. The spatial econometric is used to define econometrically the real estate market dominant area

Une interface est une zone de l'espace qui sépare deux régions possédant des propriétés physiques différentes. La plupart des interfaces de la nature résultent d'un processus de croissance, mêlant une composante aléatoire et une dynamique déterministe régie par les symétries du problème. Le résultat du processus de croissance est un objet présentant des corrélations à longue portée. Dans cette thèse, nous nous proposons d'étudier la statistique d'extrême de différents types d'interfaces. Une première motivation est de raffiner la compréhension géométrique de tels objets, via leur maximum. Une seconde motivation s'inscrit dans la démarche plus générale de la statistique d'extrême de variables aléatoires fortement corrélées. A l'aide de méthodes analytiques d'intégrales de chemin nous analysons la distribution du maximum d'interfaces à l'équilibre, dont l'énergie es t purement élastique à courte portée. Nous attaquons ensuite le problème d'interfaces élastiques en milieu désordonné, principalement à l'aide de simulations numériques. Enfin nous étudierons une interface hors-équilibre dans son régime de croissance. L'équivalence de ce type d'interface avec le polymère dirigé en milieu aléatoire, un des paradigmes de la physique statistique des systèmes désordonnés, donne une portée étendue aux résultats concernant la statistique du maximum de l'interface. Nous exposerons les résultats que nous avons obtenus sur un modèle de mouvements browniens qui ne se croisent pas, tout en explicitant le lien entre ce modèle, l'interface en croissance et le polymère dirigé. / An interface is an area of space that separates two regions having different physical properties. Most interfaces in nature are the result of a growth process, mixing a random behavior and a deterministic dynamic derived from the symmetries of the problem. This growth process gives an object with extended correlations. In this thesis, we focus on the study of the extremum of different kinds of interfaces. A first motivation is to refine the geometric properties of such objects, looking at their maximum. A second motivation is to explore the extreme value statistics of strongly correlated random variables. Using path integral techniques we analyse the probability distribution of the maximum of equilibrium interfaces, possessing short range elastic energy. We then extend this to elastic interfaces in random media, with essentially numerical simulations. Finally we study a particular type of out-of-equilibrium interface, in its growing regime. Such interface is equivalent to the directed polymer in random media, a paradigm of the statistical mechanics of disordered systems. This equivalence reinforces the interest in the extreme value statistics of the interface. We will show the exact results we obtained for a non-intersecting Brownian motion model, explaining precisely the link with the growing interface and the directed polymer.