Thèse qui propose d'analyser le processus de construction de la politique spatiale européenne. La question au coeur de la recherche est de comprendre pourquoi, alors qu’il fut initialement décidé de ne pas s’en remettre au cadre offert pas la Communauté pour européaniser les efforts naissants de coopération spatiale, put-on assister, à la fin des années 1980, à une implication grandissante de la Communauté européenne, qui se traduisit progressivement par une nouvelle européanisation du spatial ?La thèse défendue est que, loin de résulter uniquement de la confrontation et du choc des intérêts portés par les différents Etats, la politique spatiale européenne a été progressivement construite au travers d’un parcours historique dans lequel ont été impliqués différents espaces sociaux régis par des référentiels et des normes qui leur sont propres. / Doctorat en Sciences politiques et sociales / info:eu-repo/semantics/nonPublished

Galilée (1564-1642) a introduit dans son Il Saggiatore (1623) une nouvelle conception du corps. L’ontologie et la théorie de la connaissance des corps de Spinoza peuvent être conçues comme une réponse à Galilée. En effet, le philosophe hollandais répète de nombreuses fois que les qualités sensibles n’appartiennent pas aux corps en soi. En outre, il précise que les idées des affections sont des idées inadéquates qui représentent plutôt le corps affecté que les corps affectants. Néanmoins, Spinoza (1632-1677) donne une interprétation tout à fait particulière de cette conception galiléenne. Comme il le précise dans sa définition de l’Abrégé de physique, un corps en soi est un ensemble de parties qui sont unies par un rapport mutuel de mouvement et de repos. Ce ratio est à concevoir comme une nature, une proportion ou une loi physique d’un corps. Par sa nouvelle conception du corps, Galilée a dépassé la distinction ontologique entre les corps artificiels et les corps naturels, ouvrant la voie à l’application des modèles et des analogies. A première vue, Spinoza n’applique pas le modèle du pendule. Néanmoins, une étude plus détaillée dévoile l’importance de la physique de l’horloge pendulaire (inventée par Galilée et perfectionnée par Chr. Huygens) dans la conception spinoziste du corps. Dans sa définition du corps de l’E1, Spinoza conçoit le corps dans sa relation avec l’essence de Dieu. Néanmoins, dans sa CM, il a introduit le conatus ou l’essence d’une chose en donnant le paradigme d’un corps en mouvement. Comme Galilée l’avait démontré, le mouvement est essentiellement une force. Spinoza a généralisé cette idée de force, comme il l’a fait avec l’idée de loi de la nature. / In Il Saggiatore (1623), Galileo (1564-1642) introduced a novel conception of the body. Spinoza’s ontology and epistemology can be viewed as original responses to this. Indeed, the author of the Ethics writes repeatedly that sensible qualities do not belong to the body as such. Moreover, he clearly states that the ideas of affections are inadequate, representing much less the intrinsic properties of external bodies than the affected body itself. However, Spinoza (1632-1677) gives a very particular interpretation of the Galilean conception. As he makes clear in his Physical Interlude, a body consists in a group of parts united by a mutual relation of motion and rest. Furthermore, this relation is to conceived as a nature, proportion or physical law of the body. By means of his new conception, Galileo radically upended the ontological distinction between artificial and natural bodies, which opened the door to the application of models and analogies for the explanation of natural phenomena. At a first glance, Spinoza does not apply the model of the pendulum clock, which was a leading model of the 17th century. However, a closer look reveals the importance of the physics of the pendulum clock (invented by Galileo and perfected by Christian Huygens) for Spinoza’s conception of the body. In his definition in E1, Spinoza conceives of the body in its relation to the essence of God. In his CM, however, he had introduced the conatus, or the essence of a thing, in terms of the paradigm of the body in motion. As Galileo had shown, motion is essentially a force. Spinoza generalized this notion of force, just as he generalized the idea of the law of nature.

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Notre thèse étudie la relation entre les mécaniques classique et relativiste. Il est généralement supposé, à partir de l’hypothèse des petites vitesses, que la mécanique classique correspond à la mécanique relativiste dans les cas où la vitesse des objets est petite par rapport à la vitesse de la lumière. Cette position nous semble inadéquate pour la simple raison que la mécanique classique ne peut être restreinte au seule domaine des petites vitesses. Nous proposons l’hypothèse que les deux mécaniques ont une structure commune et que chacune se distingue sous certaines conditions. Pour appuyer cette hypothèse, nous proposons une axiomatisation de la mécanique suffisamment générale pour servir de structure commune aux mécaniques classique et relativiste. Cette axiomatisation comporte une théorie de la relativité qui précise comment les quantités relatives sont reliées entre elles lorsque déterminées par rapport à différents référentiels, et les lois du mouvement qui précisent comment les forces exercées sur un objet détermine son mouvement. Cette mécanique générale est déterminée à deux constantes près et c’est en déterminant la valeur de ces constantes qu’apparaît le bris de la structure commune qui génère la mécanique classique d’une part et la mécanique relativiste d’autre part. / Our thesis studies the relationship between classical and relativistic mechanics. It is generally assumed, based on the assumption of small velocities, that classical mechanics corresponds to relativistic mechanics in cases where the speed of objects is small compared to the speed of light. This position seems inadequate to us, for the simple reason that classical mechanics cannot be restricted to the realm of small velocities alone. We propose the hypothesis that the two mechanics have a common structure, and that each can be distinguished under certain conditions. To support this hypothesis, we propose an axiomatization of mechanics that is sufficiently general to serve as a common structure for both classical and relativistic mechanics. This axiomatization includes a theory of relativity that specifies how relative quantities are related to each other when determined with respect to different reference frames, and laws of motion that specify how forces exerted on an object determine its motion. This general mechanics is determined to within two constants, and it is by determining the value of these constants that the common structure that generates classical mechanics on the one hand and relativistic mechanics on the other is broken down.

The study aimed to examine high school student usage of licensed databases available through public libraries in Atlanta-USA. A descriptive quantitative survey was conducted via a web-based questionnaire among 135 East Cobb high school students. The findings revealed that most students are aware of these licensed databases, but their usage is low (1:10) compared to Google. However, as students advance in grade levels, their database usage increases and GALILEO is the most-used licensed resource. Factors that influence student database usage include: specific academic needs; teacher instruction to use specific databases and frequent Digital Information Literacy (DIL) instruction. Most students receive DIL instruction at school, but their DIL skills are still inadequate. To increase usage of licensed databases as reliable information resources, the study recommends collaboration between public libraries and high schools, including incorporation of Generation Y's digital information preferences such as Google-type simplified interfaces, cutting-edge technology and time-saving search features. / Information Science / M.A. (Information Science)

Cette thèse porte sur l'étude des techniques d'estimation Bayesienne non-linéaire, et leur applications aux problèmes de synchronisation pour des systèmes de communication par satellite, ainsi qu'au calcul des bornes Bayesiennes pour le problème de synchronisation suréchantillonné. D'abord, on présente le filtrage de Kalman et les méthodes particulaires, et l'on propose une nouvelle vue d'ensemble des méthodes déterministes. Ensuite, on établie la modélisation pour le probléme de la synchronisation fractionnée dans des systémes satellite, et l'on calcule la borne de Cramér-Rao Bayesienne pour le probléme d'estimation de phase, et la borne de Cramér-Rao hybride pour le probléme d'estimation conjointe de phase et d'offset de fréquence. Dans un deuxième temps, on applique les méthodes de filtrage (Kalman, particulaires et déterministes) aux problèmes d'estimation de phase, d'estimation conjointe de phase et d'offset de fréquence, d'estimation de délai et d'estimation de phase avec des bruits non-Gaussiens. Les méthodes proposées ont montré de bonnes performances pour nos problèmes de synchronisation. On présente aussi dans cette thèse, trois études liées aux travaux principaux. Le premier concerne l'estimation conjointe des gains complexes et du délai dans un canal de Rayleigh à variations lentes pour des signaux CPM. Le deuxième présente l'utilisation des méthodes déterministes pour la localisation avec un réseau de capteurs. Et finalement, le troisième présente le couplage GNSS/INS ultra précis et une solution déterministes à cette problèmatique.

The primary importance of trajectory reconstruction is to assess the accuracy of pre-flight predictions of the entry trajectory. While numerous entry systems have flown, often these systems are not adequately instrumented or the flight team not adequately funded to perform the statistical engineering reconstruction required to quantify performance and feed-forward lessons learned into future missions. As such, entry system performance and reliability levels remain unsubstantiated and improvement in aerothermodynamic and flight dynamics modeling remains data poor. The comparison is done in an effort to quantitatively and qualitatively compare Kalman filtering methods of reconstructing trajectories and atmospheric conditions from entry systems flight data. The first Kalman filter used is the extended Kalman filter. Extended Kalman filtering has been used extensively in trajectory reconstruction both for orbiting spacecraft and for planetary probes. The second Kalman filter is the unscented Kalman filter. Additionally, a technique for using collocation to reconstruct trajectories is formulated, and collocation's usefulness for trajectory simulation is demonstrated for entry, descent, and landing trajectories using a method developed here to deterministically find the state variables of the trajectory without nonlinear programming. Such an approach could allow one to utilize the same collocation trajectory design tools for the subsequent reconstruction.

The study aimed to examine high school student usage of licensed databases available through public libraries in Atlanta-USA. A descriptive quantitative survey was conducted via a web-based questionnaire among 135 East Cobb high school students. The findings revealed that most students are aware of these licensed databases, but their usage is low (1:10) compared to Google. However, as students advance in grade levels, their database usage increases and GALILEO is the most-used licensed resource. Factors that influence student database usage include: specific academic needs; teacher instruction to use specific databases and frequent Digital Information Literacy (DIL) instruction. Most students receive DIL instruction at school, but their DIL skills are still inadequate. To increase usage of licensed databases as reliable information resources, the study recommends collaboration between public libraries and high schools, including incorporation of Generation Y's digital information preferences such as Google-type simplified interfaces, cutting-edge technology and time-saving search features. / Information Science / M.A. (Information Science)

Satellite navigation (such as GPS) has become widely successful and is used by billions of users daily. Accuratepositioning and timing has a wide range of applications and is increasingly being integrated in safety criticalsystems such as autonomous operations, traffic management, navigation for airplanes and other vehicles. Thesecurity and vulnerabilities of satellite navigation is however often not considered in the same way as for exampledata security, even though the high efficacy of spoofing with off-the-self software-defined radio (SDR) has beendemonstrated repeatedly. The lack of concern comes partially from the lack of options as satellite navigationauthentication has not previously existed in the civil domain.This work benchmarks the anti-spoofing and signal level measurements of commercial receivers in both simulatedand real-world scenarios and implements additional anti-spoofing measures. The additional anti-spoofingmeasures are implemented using no additional information than what the receiver should already have accessto in any modern commercial vehicle. Upcoming EU regulation 2021/1228 for vehicles used in internationaltransport will also mandate the use of these three anti-spoofing measures by August 2023. Here receiver time isverified by the means of Network Time Protocol (NTP) and real time clock (RTC); receiver motion is verifiedby the means of dead reckoning and inertial measurement unit (IMU); receiver navigation data is verified by themeans of asymmetric cryptography and Galileo Open Service Navigation Message Authentication (OSNMA).The computational overhead is analyzed as well as cost and worldwide Market feasibility. We estimate thateven basic timing devices would only have to perform one NTP request every 17 days and a microcontrollerpowerful enough to do OSNMA costs less than $2. Finally, the benefits of multi-band receivers and futuredevelopments in both the user and space segments are discussed.

This work presents steps in creation of remote position tracking application. Document introduces history of geographical positioning and navigation, and describes development of navigation from primitive utilities to complex radio navigation systems. Global Positioning System is described in more detail including NMEA protocol used by GPS receivers. This work also presents several current navigation applications. Based on obtained information work presents analysis, object-oriented design and implementation of remote position tracking system.