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1

Strano, Bruno. "UAV: Design,Simulation and Control". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.

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Search and rescue operations in the Alpine area must be carried out as soon as possible to safeguard the lives of those involved in an accident. The use of drones in this area is of great interest due to the effectiveness with which it is possible to carry out SER operations in a short time. The AirBorne project deals with the development and study of drones to be applied in this field, in collaboration with the Aslatech company. This thesis aims to analyze the construction techniques of these drones and analyze the differences between two configurations to select the best components to be included in a final configuration. It also analyzes a key point for drones used in SER operations, ie control. An obstacle avoidance algorithm is presented and analyzed based on the use of artificial potentials. A simulation environment is then presented and analyzed in which a drone with ultrasound sensors will be simulated. A version of the obstacle avoidance control will be adapted to the specific case of ultrasonic sensors, analyzing the differences and testing their performance and feasibility
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2

Uznanski, Slawosz. "Monte-Carlo simulation and contribution to understanding of Single-Event-Upset (SEU) mechanisms in CMOS technologies down to 20nm technological node". Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10222/document.

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L’augmentation de la densité et la réduction de la tension d’alimentation des circuits intégrés rend la contribution des effets singuliers induits par les radiations majoritaire dans la diminution de la fiabilité des composants électroniques aussi bien dans l’environnement radiatif spatial que terrestre. Cette étude porte sur la modélisation des mécanismes physiques qui conduisent à ces aléas logiques (en anglais "Soft Errors"). Ces modèles sont utilisés dans une plateforme de simulation,appelée TIARA (Tool suIte for rAdiation Reliability Assessment), qui a été développée dans le cadre de cette thèse. Cet outil est capable de prédire la sensibilité de nombreuses architectures de circuits (SRAM,Flip-Flop, etc.) dans différents environnements radiatifs et sous différentes conditions de test (alimentation, altitude, etc.) Cette plateforme a été amplement validée grâce à la comparaison avec des mesures expérimentales effectuées sur différents circuits de test fabriqués par STMicroelectronics. La plateforme TIARA a ensuite été utilisée pour la conception de circuits durcis aux radiations et a permis de participer à la compréhension des mécanismes des aléas logiques jusqu’au noeud technologique 20nm
Aggressive integrated circuit density increase and power supply scaling have propelled Single Event Effects to the forefront of reliability concerns in ground-based and space-bound electronic systems. This study focuses on modeling of Single Event physical phenomena. To enable performing reliability assessment, a complete simulation platform named Tool suIte for rAdiation Reliability Assessment (TIARA) has been developed that allows performing sensitivity prediction of different digital circuits (SRAM, Flip-Flops, etc.) in different radiation environments and at different operating conditions (power supply voltage,altitude, etc.) TIARA has been extensively validated with experimental data for space and terrestrial radiation environments using different test vehicles manufactured by STMicroelectronics. Finally, the platform has been used during rad-hard digital circuits design and to provide insights into radiation-induced upset mechanisms down to CMOS 20nm technological node
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3

Mazzolo, Lisa-Marie. "Étude et développement d’un outil efficace de simulation pour l’évaluation de SER : Application à la détection d’objets enfouis à partir de plates-formes aéroportées". Electronic Thesis or Diss., Toulouse, ISAE, 2024. http://www.theses.fr/2024ESAE0047.

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La détection d'objets enfouis, qu'il s'agisse d'engins explosifs dans un contexte militaire ou de structures archéologiques dans un contexte civil, constitue une préoccupation majeure. En termes de télédétection radar, les systèmes aéroportés, comme le radar à synthèse d’ouverture (SAR), permettent une imagerie non destructive des sous-sols tout en offrant la possibilité d'explorer de vastes zones avec une distance de sécurité par rapport à celles-ci. Cependant, leur efficacité pour la détection d’objets enfouis dépend de nombreux facteurs, tels que les caractéristiques diélectriques du sol, qui affectent la profondeur de pénétration des ondes électromagnétiques, la nature des cibles, le type d'émetteur... Une étude préliminaire, permettant de prédire la réponse des cibles en fonction des caractéristiques des systèmes et de la scène, serait alors un outil précieux pour évaluer les capacités de détection avant d'engager des campagnes de mesures.Cette thèse s'inscrit dans ce contexte, en se concentrant sur la recherche, le développement et l'optimisation d'un outil de simulation numérique destiné à évaluer précisément la surface équivalente radar (SER) d'objets enfouis. L'approche proposée repose sur une stratégie d'hybridation de solveurs FVTD (Finite Volume Time Domain) appliquée à des maillages hybrides cartésiens / non-structurés dans l'optique d'optimiser les coûts de calcul. En particulier, ces maillages hybrides permettent une représentation conforme des géométries courbes et une discrétisation spatiale localement adaptée aux vitesses de propagation des ondes électromagnétiques dans les différents milieux de la scène de calcul. La procédure d'obtention de ces maillages, basée sur le découpage du domaine de calcul en sous-domaines est détaillée, et les solveurs FVTD utilisés sont décrits en soulignant les choix effectués pour optimiser leur efficacité. L'implémentation des modèles permettant une description représentative du sol, la prise en compte précise d'une source de type onde plane et le calcul de champs lointains en présence d'un milieu avec pertes, est également abordée. L'hybridation des solveurs FVTD via une stratégie multi-domaines / multi-méthodes est présentée en détail, en mettant l'accent sur l'architecture logicielle proposée et en précisant la stabilité de la solution hybride ainsi que les enjeux de l'hybridation. Enfin, une comparaison de résultats simulés avec des données expérimentales obtenues dans le cadre d'une campagne de mesures mise en œuvre pour cette thèse, fournit une première appréciation des performances de l'outil de simulation développé. Pour conclure, la thèse met en avant la possibilité d'utiliser cet outil pour étudier l'impact des paramètres de configuration des systèmes radar sur la SER d'objets enfouis pour des scénarios donnés
The detection of buried objects, whether explosive devices in a military context or archaeological structures in a civilian context, is a major concern. In radar remote sensing, airborne systems such as Synthetic Aperture Radar (SAR) allow non-destructive imaging of subsurface environments while offering the possibility of exploring large areas from a safe distance. However, their effectiveness in detecting buried objects depends on many factors, such as the dielectric properties of the soil, which affect the penetration depth of electromagnetic waves, the nature of targets, and the type of transmitter... A preliminary study that predicts target response based on system and scene characteristics would be a valuable tool for assessing detection capabilities before launching measurement campaigns.This thesis addresses such context by focusing on the research, development, and optimization of a numerical simulation tool designed to accurately evaluate the radar cross-section (RCS) of buried objects. The proposed approach is based on a hybridization strategy using Finite Volume Time Domain (FVTD) solvers applied to hybrid Cartesian/unstructured meshes to optimize computational costs. More specifically, these hybrid meshes allow for a conformal representation of curved geometries and spatial discretization adapted to the varying electromagnetic wave propagation speeds in different media. The procedure for generating these meshes, based on the subdivision of the computational domain into subdomains is detailed, and used FVTD solvers are described, highlighting the choices made to optimize their efficiency. The implementation of models for representative soil description, accurate handling of plane-wave sources, and far-field calculations in lossy media are also addressed. The hybridization of FVTD solvers through a multi-domain/multi-method strategy is presented in detail, emphasizing proposed software architecture, the stability of the hybrid solution, and the challenges of hybridization. Finally, a comparison of simulated results with experimental data obtained during a measurement campaign conducted for this thesis provides an initial assessment of the performance of developed simulation tool. In conclusion, this thesis highlights the potential of this tool in studying the impact of radar system configuration parameters on buried objects RCS in given scenarios
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4

Santos, Sunny Gabriella dos. "A DESCONSTRUÇÃO DO SER E DA ARTE NAS OBRAS PERTO DO CORAÇÃO SELVAGEM E PAIXÃO SEGUNDO GH, DE CLARICE LISPECTOR". Pontifícia Universidade Católica de Goiás, 2017. http://tede2.pucgoias.edu.br:8080/handle/tede/3640.

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This research aims to understand the artistic language of the writing of Clarice Lispector in the works Near the Wild Heart and Passion according to G.H., by Clarice Lispector. The narrative procedure adopted by Clarice Lispector in these works led us to the concepts related to modern and contemporary art, since we will investigate what are the aesthetic characteristics present in the author's writing that suggest such a connection. Thus, it is proposed to study the process of deconstruction of Being and Art from the perspective of the flow of language and the dereference of the Signature Image. The study will be based on contemporary critical theories, considering the rupture of the notion of art as a representation of reality. The theoretical reference for the analysis of the works will be Heidegger's conceptions of the notion of Being in its relationship with time and language, focusing on aspects related to the fragmentation of being-time; The deterritorialization of the artistic act in language to the infinite, in the perspectives of Michel Foucault, Gilles Deleuze and Félix Guattari and, interconnected with the notions of liquid modernity, of ZygmundBauman and the derealization of the work of art.The analysis of the works will be based on the search for the "essentialization" of the Being of the characters by the language (Near the wild heart) and the depersonalization of Being (Passion according to GH) in the context of a work marked by the principle of derealization and dereferentiation of the image -sign - a simulation process, in the view of Jean Baudrillard (1991).
Esta pesquisa visa compreender a linguagem artística da escritura de Clarice Lispector nas obras Perto do coração selvagem e Paixão segundo GH, de Clarice Lispector. O procedimento narrativo adotado por Clarice Lispector nessas obras levou-nos aos conceitos ligados a arte moderna e contemporânea, uma vez que investigaremos quais são as características estéticas presentes na escritura da autora que sugerem tal ligação. Assim, propõe-se estudar o processo de desconstrução do Ser e da Arte sob a perspectiva do fluxo da linguagem e da desreferencialização da Imagem-Signo. O estudo será fundamentado nas teorias críticas contemporâneas, considerando a ruptura da noção de arte como representação da realidade. O referencial teórico de análise das obras serão as concepções de Heidegger sobre a noção do Ser em sua relação com o tempo e a linguagem, focalizando os aspectos relativos à fragmentação do ser-tempo; a desterritorialização do ato artístico em linguagem ao infinito, nas perspectivas de Michel Foucault, Gilles Deleuze e Félix Guattari e, interconectadas às noções de modernidade líquida, de Zygmund Bauman e à desrealização da obra de arte. A análise das obras terá como norte a busca da “essencialização” do Ser das personagens pela linguagem (Perto do coração selvagem) e a despersonalização do Ser (Paixão segundo GH) no contexto de uma obra marcada pelo princípio de desrealização e de desreferencialização da imagem-signo – um processo de simulação, na visão de Jean Baudrillard (1991).
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5

Bui, Nicolas. "Méthode FDTD conforme et d’ordre (2,4) pour le calcul de SER large bande de cibles complexes". Thesis, Limoges, 2016. http://www.theses.fr/2016LIMO0118/document.

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L'évaluation précise de la surface équivalente radar (SER) large bande de cibles complexes et de grande dimension est réalisée par des méthodes numériques rigoureuses. Parmi celles-ci, la méthode des différences finies dans le domaine temporel (FDTD) est bien adaptée pour effectuer ce calcul de SER sur une large bande de fréquence et obtenir une signature temporelle de la cible. Le schéma de Yee, schéma FDTD historique pour la simulation de propagation d'ondes électromagnétiques en régime transitoire, souffre de deux points faibles cruciaux: la dispersion numérique imposant une finesse de maillage; et l'approximation de la géométrie curviligne par un maillage cartésien avec des marches d'escalier détériorant la qualité des résultats. Les schémas FDTD d'ordre supérieur en espace ont été investigués pour la réduction de l'effet de la dispersion numérique. Dans cette thèse, le schéma Conservative Modified FDTD(2,4) a été développé dont les performances, en précision et en ressources, sont très intéressantes pour le calcul de SER. Liés au problème de l'approximation de la géométrie curviligne, le traitement des bords de plaques métalliques reste une difficulté non résolue pour les schémas FDTD(2,4) à stencil élargi. Les techniques conformes sont des approches développées pour le schéma de Yee, lesquelles ont été étudiées pour les schémas FDTD(2,4) afin de prendre en compte correctement la géométrie curviligne. Nous proposons une nouvelle approche reposant sur le modèle des fils obliques pour la modélisation des éléments surfaciques métalliques. Des applications SER de cibles montrent que celle-ci est prometteuse
Rigorous numerical methods are used to compute an accurate wideband radar cross section (RCS) evaluation of large complex targets. Among these, finite differences in time domain method is appropriated for the wideband characteristic and also to obtain a transient responses of the target. The Yee scheme, known historically as an FDTD scheme for Maxwell equations, is hindered by two crucial weak points: numerical dispersion which imposes a high mesh resolution; and staircase approximation of curve geometry which deteriorates results quality. High-order space differential operator for FDTD schemes have been investigated to limit numerical dispersion errors. In this thesis, the Conservative Modified FDTD(2,4) scheme has been developed and its performance has shown very accurate results with reasonable workload for RCS computation. Relating to curve geometry modeling problem, metallic edges modeling is still an unsolved problem for FDTD(2,4) schemes with enlarged stencil. Conformal techniques have been developed for the Yee scheme and has been studied for FDTD(2,4) to accurately model curve geometry. We propose a new approach based on oblique thin wire model to model metallic surfaces. RCS computations of several targets have shown that this method is promising
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6

Oyedokun, Titus Oluwale. "Sea clutter simulation". Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/14557.

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Includes bibliograpical references.
This dissertation presents the results of a study, the aim of which was the prediction of sea clutter characteristics including the temporal properties of the return signals as observed by a maritime surveillance radar system. The compound K distribution model used to generate clutter amplitude statistic enables the simulation of sea clutter with a good level of approximation to real radar data and this model forms the basis for the simulation of sea clutter amplitude statistic in this dissertation. Using this distribution, a sea clutter simulator is designed to generate correlated K distributed random variates from a predefined correlation function using the method by Ward and Tough [1 ]. Results from the sea clutter simulator shows that the simulated correlated random variates fit the theoretical K distribution PDF. Experimental sea clutter measurements were carried out using an experimental netted radar system. This was done at Scarborough Cape Town. Result obtained from the monostatic node is presented. This shows the amplitude statistics of the clutter as well as the temporal variation of the Doppler spectrum. Conclusions are drawn based on this results and suggestions made for further work.
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7

Rogerson, Stuart Peter. "Implementation of a distributed interactive simulation interface in a Sea King flight simulator". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29371.pdf.

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8

Arzur, Fabien. "Développement de simulateurs de cibles pour radars automobiles 77 GHz". Thesis, Brest, 2017. http://www.theses.fr/2017BRES0082.

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Le travail présenté dans ce manuscrit porte sur le développement d’un simulateur de cible (RTS) pour radars automobiles 77 GHz. Afin de proposer des véhicules toujours plus sûrs, les constructeurs automobiles développent des systèmes ADAS de plus en plus performants. On assiste aujourd’hui à la démocratisation des radars automobiles d’alerte à la collision et de régulation de distance. La généralisation de tels systèmes sur des véhicules de série va nécessiter le recours accru à des moyens de tests, chez les constructeurs et dans les centres de contrôle technique. Pour pouvoir tester et calibrer les radars, il est nécessaire d’utiliser des RTS. Ces appareils permettent de simuler les scénarios rencontrés par le radar, ceux-ci devenant plus complexes avec le développement des voitures autonomes. Une cible est définie par trois paramètres : une vitesse, une distance et une SER. Afin de répondre à des exigences drastiques, Autocruise développe ses propres RTS pour des bancs de test de production et de R&D. Ils doivent s’adapter à tout radar fonctionnant sur la bande 76 – 81 GHz, avec différentes modulations et une bande de fréquence supérieure à 800 MHz. Le système doit être à bas coût, de faibles dimensions et flexible pour être intégré dans différentes applications. Le principal verrou technologique est la réalisation d’une ligne à retard variable, capable de simuler des distances comprises entre 1 m et 250 m, avec une résolution de 0,2 m et permettre le contrôle de la SER. Un compromis devra être trouvé afin de répondre aux spécifications. L’étude a montré l’impossibilité de couvrir l’ensemble de la plage de distances avec une seule technologie. Une architecture hybride est indispensable. Une ligne à retard hybride reconfigurable large bande est présentée
The work presented in this thesis concerns the development of an automotive radar target simulator for 77 GHz radar sensors. In order to continue offering safer vehicles, manufacturers develop more and more performant ADAS systems. We are witnessing a democratization of automotive radar sensors for adaptive cruise control and collision warning. The generalization of such systems on standard cars will require an increased use of test devices both at the manufacturers and in technical control centers. To test and calibrate radars, it is necessary to use Radar Target Simulators (RTS). These devices enable to simulate situations encountered by the radar. Furthermore, these scenarios are becoming increasingly complex with the arrival of autonomous vehicles. A target is defined by three parameters: distance, velocity and radar cross-section (RCS). In order to meet drastic requirements, ZF TRW Autocruise develops its own RTS for production test benches and R&D. RTS must adapt to all radars within a 76 – 81 GHz frequency band, with different modulations and a frequency bandwidth higher than 800 MHz. The system must present the advantages of being a low-cost system, with small dimensions and flexible to be integrated in different applications. The major blocking point is the design of a reconfigurable delay line, able to simulate distances between 1 m and 250 m with a resolution of 0.2 m on a large frequency band and also allowing control of RCS. A compromise will have to be found in order to meet the different specifications. The study showed the impossibility to cover the entire range of distances with one single technology. A hybrid architecture is necessary. A hybrid, tunable, wideband delay line is at study
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9

Malherbe, Victor. "Multi-scale modeling of radiation effects for emerging space electronics : from transistors to chips in orbit". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0753/document.

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En raison de leur impact sur la fiabilité des systèmes, les effets du rayonnement cosmique sur l’électronique ont été étudiés dès le début de l’exploration spatiale. Néanmoins, de récentes évolutions industrielles bouleversent les pratiques dans le domaine, les technologies standard devenant de plus en plus attrayantes pour réaliser des circuits durcis aux radiations. Du fait de leurs fréquences élevées, des nouvelles architectures de transistor et des temps de durcissement réduits, les puces fabriquées suivant les derniers procédés CMOS posent de nombreux défis. Ce travail s’attelle donc à la simulation des aléas logiques permanents (SEU) et transitoires (SET), en technologies FD-SOI et bulk Si avancées. La réponse radiative des transistors FD-SOI 28 nm est tout d’abord étudiée par le biais de simulations TCAD, amenant au développement de deux modèles innovants pour décrire les courants induits par particules ionisantes en FD-SOI. Le premier est principalement comportemental, tandis que le second capture des phénomènes complexes tels que l’amplification bipolaire parasite et la rétroaction du circuit, à partir des premiers principes de semi-conducteurs et en accord avec les simulations TCAD poussées.Ces modèles compacts sont alors couplés à une plateforme de simulation Monte Carlo du taux d’erreurs radiatives (SER) conduisant à une large validation sur des données expérimentales recueillies sous faisceau de particules. Enfin, des études par simulation prédictive sont présentées sur des cellules mémoire et portes logiques en FD-SOI 28 nm et bulk Si 65 nm, permettant d’approfondir la compréhension des mécanismes contribuant au SER en orbite des circuits intégrés modernes
The effects of cosmic radiation on electronics have been studied since the early days of space exploration, given the severe reliability constraints arising from harsh space environments. However, recent evolutions in the space industry landscape are changing radiation effects practices and methodologies, with mainstream technologies becoming increasingly attractive for radiation-hardened integrated circuits. Due to their high operating frequencies, new transistor architectures, and short rad-hard development times, chips manufactured in latest CMOS processes pose a variety of challenges, both from an experimental standpoint and for modeling perspectives. This work thus focuses on simulating single-event upsets and transients in advanced FD-SOI and bulk silicon processes.The soft-error response of 28 nm FD-SOI transistors is first investigated through TCAD simulations, allowing to develop two innovative models for radiation-induced currents in FD-SOI. One of them is mainly behavioral, while the other captures complex phenomena, such as parasitic bipolar amplification and circuit feedback effects, from first semiconductor principles and in agreement with detailed TCAD simulations.These compact models are then interfaced to a complete Monte Carlo Soft-Error Rate (SER) simulation platform, leading to extensive validation against experimental data collected on several test vehicles under accelerated particle beams. Finally, predictive simulation studies are presented on bit-cells, sequential and combinational logic gates in 28 nm FD-SOI and 65 nm bulk Si, providing insights into the mechanisms that contribute to the SER of modern integrated circuits in orbit
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10

Malherbe, Victor. "Multi-scale modeling of radiation effects for emerging space electronics : from transistors to chips in orbit". Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0753.

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Abstract (sommario):
En raison de leur impact sur la fiabilité des systèmes, les effets du rayonnement cosmique sur l’électronique ont été étudiés dès le début de l’exploration spatiale. Néanmoins, de récentes évolutions industrielles bouleversent les pratiques dans le domaine, les technologies standard devenant de plus en plus attrayantes pour réaliser des circuits durcis aux radiations. Du fait de leurs fréquences élevées, des nouvelles architectures de transistor et des temps de durcissement réduits, les puces fabriquées suivant les derniers procédés CMOS posent de nombreux défis. Ce travail s’attelle donc à la simulation des aléas logiques permanents (SEU) et transitoires (SET), en technologies FD-SOI et bulk Si avancées. La réponse radiative des transistors FD-SOI 28 nm est tout d’abord étudiée par le biais de simulations TCAD, amenant au développement de deux modèles innovants pour décrire les courants induits par particules ionisantes en FD-SOI. Le premier est principalement comportemental, tandis que le second capture des phénomènes complexes tels que l’amplification bipolaire parasite et la rétroaction du circuit, à partir des premiers principes de semi-conducteurs et en accord avec les simulations TCAD poussées.Ces modèles compacts sont alors couplés à une plateforme de simulation Monte Carlo du taux d’erreurs radiatives (SER) conduisant à une large validation sur des données expérimentales recueillies sous faisceau de particules. Enfin, des études par simulation prédictive sont présentées sur des cellules mémoire et portes logiques en FD-SOI 28 nm et bulk Si 65 nm, permettant d’approfondir la compréhension des mécanismes contribuant au SER en orbite des circuits intégrés modernes
The effects of cosmic radiation on electronics have been studied since the early days of space exploration, given the severe reliability constraints arising from harsh space environments. However, recent evolutions in the space industry landscape are changing radiation effects practices and methodologies, with mainstream technologies becoming increasingly attractive for radiation-hardened integrated circuits. Due to their high operating frequencies, new transistor architectures, and short rad-hard development times, chips manufactured in latest CMOS processes pose a variety of challenges, both from an experimental standpoint and for modeling perspectives. This work thus focuses on simulating single-event upsets and transients in advanced FD-SOI and bulk silicon processes.The soft-error response of 28 nm FD-SOI transistors is first investigated through TCAD simulations, allowing to develop two innovative models for radiation-induced currents in FD-SOI. One of them is mainly behavioral, while the other captures complex phenomena, such as parasitic bipolar amplification and circuit feedback effects, from first semiconductor principles and in agreement with detailed TCAD simulations.These compact models are then interfaced to a complete Monte Carlo Soft-Error Rate (SER) simulation platform, leading to extensive validation against experimental data collected on several test vehicles under accelerated particle beams. Finally, predictive simulation studies are presented on bit-cells, sequential and combinational logic gates in 28 nm FD-SOI and 65 nm bulk Si, providing insights into the mechanisms that contribute to the SER of modern integrated circuits in orbit
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11

Shoalehvar, Amin. "Synthetic Aperture Radar (SAR) Raw Signal Simulation". DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/755.

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Abstract Synthetic Aperture Radar (SAR) Raw Signal Simulation Author: Amin Shoalehvar Synthetic aperture radar (SAR) raw signal simulation is a useful tool for SAR system design, mission planning, processing algorithm testing, and inversion algorithm design. This thesis explores a SAR raw signal simulation. The raw signal simulation is the simulated received signal before any processing with exception of the down-converter. The simulation plays a significant role in studies concerning noise and clutter rejection and contributes toward optimizing SAR system parameters. To simulate SAR raw data, a Chirp Scaling (CS) method is used. This method [3] first stretches the input surface reflectivity of the target in the azimuth and range direction respectively. Then it derives the raw data by inverse equalizing the signal based on CS principle. This method avoids the time-domain integral operation and improves the computational efficiency. A simulation diagram, calculation and systematic process are proposed in this thesis. Finally, simulation results are presented to verify the accuracy of calculations and the efficiency of the process.
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12

Rodriguez, Milla Berta Elizabeth. "Numerical simulations for channel flow in disordered materials". Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.

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13

Bryan, Kyle A. "Simulation of sea based logistics support of operational maneuver from the sea". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA401221.

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Thesis (M.S. in Management) Naval Postgraduate School, December2001.
Thesis Advisor(s): Kang, Keebom ; Doerr, Kenneth. "December 2001." Includes bibliographical references (p. 79-80). Also available in print.
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14

Keckler, Andrew D. Weiner Donald D. "Non-Gaussian clutter simulation and distribution approximation using spherically invariant random vectors". Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.

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15

Heacock, Tony. "Simulation of the seasonal ice regime in Lancaster SoundBarrow Strait". Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=69661.

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A sea ice model developed by W. D. Hibler (1979) was applied to the Lancaster Sound/Barrow Strait channel in an effort to simulate the observed ice environment. The simulation covered a ten month period, from October 1985 until August 1986. The impact of atmospheric and oceanographic forcing on the development of characteristic ice features that develop seasonally within the channel was examined. The importance of the ice interaction component of the model when simulating a restricted channel ice environment was also examined. The model was able to simulate regional scale processes and conditions within the channel. Small scale localised processes and conditions which control the spatial variability and complexity of the ice regime were not accurately reproduced. Simulation results provided insights into the effect and importance of both the model and geophysical variables examined. The study highlighted concerns that need be addressed in future modelling work in the Lancaster Sound/Barrow Strait channel.
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16

Bazargan-Harandi, Hamid. "Neural network based simulation of sea-state sequences". Thesis, Brunel University, 2006. http://bura.brunel.ac.uk/handle/2438/379.

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The present PhD study, in its first part, uses artificial neural networks (ANNs), an optimization technique called simulated annealing, and statistics to simulate the significant wave height (Hs) and mean zero-up-crossing period ( ) of 3-hourly sea-states of a location in the North East Pacific using a proposed distribution called hepta-parameter spline distribution for the conditional distribution of Hs or given some inputs. Two different seven- network sets of ANNs for the simulation and prediction of Hs and were trained using 20-year observed Hs’s and ’s. The preceding Hs’s and ’s were the most important inputs given to the networks, but the starting day of the simulated period was also necessary. However, the code replaced the day with the corresponding time and the season. The networks were trained by a simulated annealing algorithm and the outputs of the two sets of networks were used for calculating the parameters of the probability density function (pdf) of the proposed hepta-parameter distribution. After the calculation of the seven parameters of the pdf from the network outputs, the Hs and of the future sea-state is predicted by generating random numbers from the corresponding pdf. In another part of the thesis, vertical piles have been studied with the goal of identifying the range of sea-states suitable for the safe pile driving operation. Pile configuration including the non-linear foundation and the gap between the pile and the pile sleeve shims were modeled using the finite elements analysis facilities within ABAQUS. Dynamic analyses of the system for a sea-state characterized by Hs and and modeled as a combination of several wave components were performed. A table of safe and unsafe sea-states was generated by repeating the analysis for various sea-states. If the prediction for a particular sea-state is repeated N times of which n times prove to be safe, then it could be said that the predicted sea-state is safe with the probability of 100(n/N)%. The last part of the thesis deals with the Hs return values. The return value is a widely used measure of wave extremes having an important role in determining the design wave used in the design of maritime structures. In this part, Hs return value was calculated demonstrating another application of the above simulation of future 3-hourly Hs’s. The maxima method for calculating return values was applied in such a way that avoids the conventional need for unrealistic assumptions. The significant wave height return value has also been calculated using the convolution concept from a model presented by Anderson et al. (2001).
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17

Desai, Amresh S. "Array-based GPR SAR simulation and image reconstruction". Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/7397.

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Bibliography: leaves 53-55.
Subsurface object detection has mainly been carried out using conventional ground penetrating radar (OPR) techniques, which use a single receiving antenna from which a number of range profiles (known as ""A Scope"" images) are assembled to form a two-dimensional data field (known as a ""B Scope"" image). These OPR systems have difficulties with high clutter level, surface reflections, limited ground penetration and the required fine resolution. The resolution in the across track and along track directions is limited by the physical aperture in these directions. This project aims at developing a SAR imaging technique, which uses a single transmitting/receiving antenna to synthesize a two-dimensional planar aperture. Thus a three-dimensional reflectivity image of a scene is generated. The resolution in the across track and along track directions is achieved via a SAR aperture synthesis technique. The depth/range resolution is achieved via the transmission of narrowband Stepped Frequency Continuous Wave (SFCW) signals.
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18

Lemcke, Mary D. "The sensitivity of CSIM5 sea-ice simulations to atmospheric state variables". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 156 p, 2009. http://proquest.umi.com/pqdweb?did=1886744831&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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19

Ozarkar, Shailesh. "Numerical simulations and theories for wall-bounded flows of suspensions". Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.

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20

Thomas, Creighton Kays. "Optimization and exact sampling algorithms for simulations of glassy materials". Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2009. http://wwwlib.umi.com/cr/syr/main.

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21

Nicolai, Andreas. "Modeling and numerical simulation of salt transport and phase transitions in unsaturated porous building materials". Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.

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22

Løset, Tarjei Kvamme. "Real-Time Simulation and Visualization of Large Sea Surfaces". Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8805.

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The open ocean is the setting for enterprises that require extensive monitoring, planning and training. In the offshore industry, virtual environments have been embraced to improve such processes. The presented work focuses on real-time simulation and visualization of open seas. This implies very large water surfaces dominated by wind-driven waves, but also influenced by the presence of watercraft activity and offshore installations. The implemented system treats sea surfaces as periodic elevation fields, obtained by synthesis from statistically sampled frequency spectra. Apparent repeating structures across a surface, due to this periodic nature, are avoided by decomposing the elevation field synthesis, using two or more discrete spectra with different frequency scales. A GPU-based water solver is also included. Its implementation features a convenient input interface, which exploits hardware rasterization both for efficiency and to supply the algorithm with arbitrary data, e.g. smooth, connected deflective paths. Finally, polygonal representations of visible ocean regions are obtained using a GPU-accelerated tessellation scheme suitable for wave fields. The result is realistic, unbounded ocean surfaces with natural distributions of wind-driven waves, avoiding the artificial periodicity associated with previous similar techniques. Further, the simulation allows for superposed boat wakes and surface obstacles in regions of interest. With the proposed tessellation scheme, the visualization is economic with regards to data transfer, conforming with the goal of delivering highly interactive rendering rates.

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23

Barratt, Nicholas Roy. "The simulation of SAR imagery using discretised scattering models". Thesis, King's College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283117.

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24

Letheule, Nathan. "Apports de l'Apprentissage Profond pour la simulation d'images SAR". Electronic Thesis or Diss., université Paris-Saclay, 2024. https://theses.hal.science/tel-04651643.

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La simulation est un outil précieux pour de nombreuses applications d'imagerie SAR, cependant, les images simulées de grandes tailles ne sont pas encore assez réalistes pour tromper un expert en images radar. Cette thèse propose d'évaluer dans quelle mesure l'utilisation des avancées récentes en matière d'apprentissage profond peut permettre d'améliorer la qualité des simulations. Dans un premier temps, nous proposons de définir une méthode de mesure de réalisme des images SAR simulées en les comparant à des images réelles. Les métriques ainsi établies serviront ensuite à l'évaluation des résultats de simulation. Dans un second temps, deux cadres de simulation basés sur l'apprentissage profond sont proposés, avec des philosophies différentes. Le premier ne prend pas en compte la connaissance physique de l'imagerie, et propose d'apprendre la transformation d'une image optique vers une image radar à l'aide d'une architecture cGAN. Le second s'appuie sur un simulateur physique développé à l'Onera (EMPRISE), et utilise la génération automatique d'entrées à partir d'une segmentation sémantique d'une image optique de la scène, via l'apprentissage profond. Pour cette dernière piste prometteuse, une réflexion est menée sur la description de l'entrée et son impact sur le résultat final de simulation. Enfin, des pistes d'enrichissement par apprentissage profond des images générées par le simulateur physique seront proposées, notamment à travers des réseaux de diffusion, et des approches text-to-image
Simulation is a valuable tool for many SAR imaging applications, however, large simulated images are not yet realistic enough to fool a radar image expert. This thesis proposes to evaluate to what extent the use of recent advances in deep learning can improve the quality of simulations. As a first step, we propose to define a method for measuring the realism of simulated SAR images by comparing them with real images. The resulting metrics will then be used to evaluate simulation results. Secondly, two simulation frameworks based on deep learning are proposed, with different philosophies. The first does not take into account physical knowledge of the imagery, and proposes to learn the transformation of an optical image into a radar image using a cGAN architecture. The second is based on a physical simulator developed at Onera (EMPRISE), and uses automatic input generation from semantic segmentation of an optical image of the scene, via deep learning. For this last promising avenue, we are looking into the description of the input and its impact on the final simulation result. Finally, we will be proposing ways of enriching the images generated by the physical simulator using deep learning, in particular through diffusion networks and text-to-image approaches
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25

Roser, Joseph E. Vidali Gianfranco. "Laboratory simulations of chemical reactions on dust grains in the interstellar medium". Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.

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26

Camur, Serhat. "A simulation tool for the duties of computer specialist non-commissioned officers on a Turkish Air Force Base". Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep_Camur.pdf.

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Thesis (M.S. in Modeling, Virtual Environments, and Simulation (MOVES))--Naval Postgraduate School, September 2009.
Thesis Advisor(s): Buss, Arnold H. "September 2009." Description based on title screen as viewed on November 03, 2009. Author(s) subject terms: Simulation, model, staff assignment problem, Simkit, Viskit, design of experiment, NOLH, and regression analysis. Includes bibliographical references (p. 73-74). Also available in print.
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27

Xiao, Amanda Z. Y. "Explaining chlorophyll concentration in the Sulu Sea with the aid of a numerical model". Thesis, The University of Sydney, 2010. https://hdl.handle.net/2123/28845.

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The Sulu Sea is almost an enclosed basin, characterised by a strong seasonally reversing monsoon which induces a complex circulation. Physical features significantly influence phytoplankton biomass which is an engine for the marine food chain that supports fish production. A high proportion of Philippinoes and Malaysians rely on fishing in the Sulu Sea to provide them with animal protein. Nutrients that support the production of marine protein are supplied to the photic zone either through upwelling or by horizontal transport.
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28

Kim, Angela M. "Simulating full-waveform LIDAR". Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FKim.pdf.

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Thesis (M.S. in Applied Mathematics)--Naval Postgraduate School, September 2009.
Thesis Advisor(s): Borges, Carlos F. ; Olsen, Richard C. "September 2009." Description based on title screen as viewed on 6 November 2009. Author(s) subject terms: LIDAR, Monte Carlo simulation, full-waveform, model. Includes bibliographical references (p. 105-108). Also available in print.
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29

Yam, Ontiveros Luis Eduardo. "Simulation, detection, and classification of vessels in maritime SAR images". Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/403883.

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Over the last decades, environmental and socio-economic factors have generated interest on the observation of the ocean. Thus, the monitoring of maritime human activity has become crucial for the protection of the marine environment, the sustainability of the industrial sector, and security of navigation. Spaceborne remote sensing technologies can be used to improve existing marine monitoring systems at a global level. In particular, the Synthetic Aperture Radar (SAR) spaceborne sensors offer significant advantages for global monitoring. These types of sensors acquire high-resolution radar images suitable for the identification of man-made objects such as artificial structures and vehicles. In addition, these images can be obtained from any part of the planet's surface with no need for natural illumination, and practically regardless of the weather conditions over the area of interest. The current spaceborne SAR sensors have the potential to complement traditional maritime monitoring systems by acting as an independent source of information for the detection and identification of presumed vessels. This research focuses on the analysis of the characteristics of maritime SAR images from spaceborne sensors, the improvement of simulation tools, and the development and evaluation of algorithms for extracting information of interest which can be applied to vessel monitoring. In particular, it takes the case of stripmap SAR single-look complex (SLC) images since this is the most basic SAR product that all of the current spaceborne sensors are capable of providing. Theoretical analysis and evaluation of simulations establish, firstly, the relation between the motions of the vessels and phase errors in their received SAR signals, and secondly, how these phase errors impact on the position and focus quality of the vessels¿ SAR signatures in the image. In this thesis, the defocus of the targets is identified as one of the factors that hinders the proper extraction of the characteristics of vessels from the shape of their SAR signature. Thus, this thesis proposes local application of classical autofocus techniques adapted to the case of stripmap SLC images, and evaluates their performance using simulated data and real images of vessels from sensors such as RADARSAT-2 and Cosmo-SkyMed. Moreover, by analysing the SAR signal of the vessels in both the image and Doppler domain, techniques for automatic extraction of features of the SAR signatures such as size, direction, range velocity component, and basic identification of the type of vessel are proposed. Finally, all these techniques are merged into a single postprocessing sequence, which this thesis proposes as an algorithm for automatic refocusing and feature extraction of detected vessels in stripmap SLC SAR images. The evaluation and analysis of the performance of this algorithm with RADARSAT-2 and Cosmo-SkyMed images suggest its potential use in operational applications, although as in the case of other vessel identification algorithms, its performance is dependent on the complexity of the SAR signatures of the vessels
Motivaciones ecológicas y socio-económicas han hecho que la observación del océano sea área de gran interés en las últimas décadas. Así, el monitoreo de la actividad humana marítima se ha tornado crucial para la protección del medio ambiente marino, la sustentabilidad del sector industrial, y la seguridad en la navegación. Para una perspectiva global, tecnologías espaciales de teledección pueden utilizarse para robustecer los actuales sistemas de monitoreo marítimo. En particular, los sensores espaciales Radar de Apertura Sintética (SAR, de sus siglas en inglés) ofrecen ventajas notables para el monitoreo global. Estos sensores pueden adquirir imágenes radar de alta resolución que permiten distinguir estructuras artificiales y vehículos; además, estas adquisiciones pueden ser de cualquier parte de la superficie del planeta sin necesidad de iluminación natural, y prácticamente, sin importar las condiciones climáticas sobre el área de interés. Los actuales sensores SAR espaciales tienen el potencial de complementar sistemas de monitoreo de tráfico marítimo convencionales, siendo una fuente de información independiente para la detección e identificación de embarcaciones. Este trabajo de investigación se enfoca en el análisis de las características de las imágenes SAR satelitales de barcos, en conjunto con la mejora de las herramientas de simulación, y el desarrollo y evaluación de algoritmos para la extracción de información de interés aplicable al monitoreo del tráfico marítimo. En específico, se toma el caso de imágenes SAR stripmap complejas (SLC, de sus siglas en inglés) dado que es el producto básico que todo sistema de teledección SAR es capaz de proveer. Primeramente, a través de un análisis teórico y evaluación de simulaciones, se relacionan los movimientos de los barcos con errores de fase en sus señales SAR captadas por el satélite, así como su impacto en la posición y desenfoque de sus respectivas imágenes. En esta tesis, se identifica este desenfoque como uno de los impedimentos para la correcta extracción de las características de los barcos basadas en la geometría de su imagen SAR. Así, se propone la aplicación local de técnicas de autoenfoque clásicas adaptadas al caso de imagen stripmap SLC, evaluando su desempeño mediante datos simulados e imágenes reales de embarcaciones en entornos marítimos de sensores como RADARSAT-2 y Cosmo-SkyMed. Por otra parte, mediante el análisis conjunto de las imágenes SAR de los barcos en el dominio espacial y espectral, se proponen técnicas para la automática extracción de información como sus dimensiones, rumbo, velocidad en rango, y básica identificación del tipo de embarcación. Finalmente, esta tesis propone la fusión de este postprocesado en un algoritmo para el reenfoque y extracción automática de características de interés de los barcos detectados en imágenes stripmap SLC. La evaluación y análisis de resultados con imágenes de RADARSAT-2 y Cosmo-SkyMed sugiere su potencial uso en aplicaciones operacionales, aunque como otros algoritmos de identificación de embarcaciones, su desempeño resulta dependiente de la complejidad de la imagen del barco.
Motivacions ecològiques i socioeconòmiques han fet que l'observació de l'oceà sigui un àrea de gran interès en les darreres dècades. Així, el monitoratge de l'activitat humana marítima ha esdevingut crucial per a la protecció del medi ambient marí, la sostenibilitat del sector industrial, i la seguretat en la navegació. Per a una perspectiva global, tecnologies espacials de Teledetecció poden utilitzar-se per reforçar els actuals sistemes de monitorització marítima. En particular, els sensors espacials Radar d'Obertura Sintètica (SAR, de les seves sigles en anglès) ofereixen avantatges notables per al monitoratge global. Aquests sensors poden adquirir imatges radar d'alta resolució que permeten distingir estructures artificials i vehicles; a més, aquestes adquisicions poden ser de qualsevol part de la superfície del planeta sense necessitat d'il·luminació natural, i pràcticament sense la influència de les condicions climàtiques sobre l'àrea d'interès. Els actuals sensors SAR espacials tenen el potencial de complementar sistemes de monitorització de trànsit marítim convencionals, sent una font d'informació independent per a la detecció i identificació d'embarcacions. Aquest treball de recerca s'enfoca en l'anàlisi de les característiques de les imatges SAR orbitals d'embarcacions, en conjunt amb la millora de les eines de simulació, i el desenvolupament i avaluació d'algoritmes per a l'extracció d'informació d'interès aplicable al monitoratge del trànsit marítim. En específic, es pren el cas d'imatges SAR stripmap complexes (SLC, de les seves sigles en anglès) atès que és el producte bàsic que tot sistema de Teledetecció SAR és capaç de proveir. Primerament, a través d'una anàlisi teòrica i avaluació de simulacions, es relacionen els moviments dels vaixells amb errors de fase en les seves senyals SAR captades pel satèl·lit, així com el seu impacte en la posició i desenfocament de les seves respectives imatges. En aquesta tesi, s'identifica aquest desenfocament com un dels impediments per a la correcta extracció de les característiques dels vaixells basades en la geometria de la seva imatge SAR. Així, es proposa l'aplicació local de tècniques d¿enfocament automàtic clàssiques adaptades al cas d'imatge stripmap SLC, avaluant el seu acompliment mitjançant dades simulades i imatges reals d'embarcacions en entorns marítims de sensors com RADARSAT-2 i Cosmo-SkyMed. D'altra banda, mitjançant l'anàlisi conjunta de les imatges SAR dels vaixells al domini espacial i espectral, es proposen tècniques per a la automàtica extracció d'informació com les seves dimensions, rumb, velocitat, i la identificació bàsica del tipus d'embarcació. Finalment, aquesta tesi proposa la fusió d'aquest postprocessat en un algoritme per el reenfocament i extracció automàtica de característiques d'interès dels vaixells detectats en imatges stripmap SLC. L'avaluació i anàlisi dels resultats amb imatges de RADARSAT-2 i Cosmo-SkyMed suggereix el seu ús potencial en aplicacions operacionals, encara que com altres algoritmes d'identificació d'embarcacions, el seu acompliment resulta depenent de la complexitat de la imatge del vaixell.
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30

Krus, Kristofer. "Wave Model and Watercraft Model for Simulation of Sea State". Thesis, Linköpings universitet, Teoretisk Fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-102959.

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The problem of real-time simulation of ocean surface waves, ship movement and the coupling in between is tackled, and a number of different methods are covered and discussed. Among these methods, the finite volume method has been implemented in an attempt to solve the problem, along with the compressible Euler equations, an octree based staggered grid which allows for easy adaptive mesh refinement, the volume of fluid method and a variant of the Hyper-C advection scheme for compressible flows for advection of the phase fraction field. The process of implementing the methods that were chosen proved to be tricky in many ways, as they involve a large number of advanced topics, and the implementation that was implemented in this thesis work suffered from numerous issues. There were for example problems with keeping the interface intact, as well as a harsh restriction on the time step size due to the CFL condition. Improvements required to make the method sustainable for real-time applications are discussed, and a few suggestions on alternative approaches that are already in use for similar purposes are also given and discussed. Furthermore, a method for compensating for gain/loss of mass when solving the incompressible flow equations with an inaccurately solved pressure Poisson equation is presented and discussed. A momentum conservative method for transporting the velocity field on staggered grids without introducing unnecessary smearing is also presented and implemented. A simple, physically based illumination model for sea surfaces is derived, discussed and compared to the Blinn–Phong shading model, although it is never implemented. Finally, a two-dimensional partial differential equation in the spatial domain for simulating water surface waves for mildly varying bottom topography is derived and discussed, although it is deemed to be too slow for real-time purposes and is therefore never implemented.

This publication differs from the printed version of the report in the sense that links are blue in this version and black in the printed version.

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31

Holland, David M. "Numerical simulation of the Arctic Sea ice and ocean circulation". Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41114.

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A numerical model study of the seasonal cycle of sea-ice cover and ocean circulation in the Arctic Ocean is presented. The investigation is carried out in four parts using the coupled sea ice-ocean model of Oberhuber (1993a). The Oberhuber model is the first global ocean general circulation model to use Lagrangian isopycnal coordinates. First, a sensitivity study is given of the sea-ice model, which is both dynamic and thermodynamic. The robustness of the sea-ice component in an uncoupled mode is demonstrated. Secondly, the addition of a snow model to the coupled sea ice-ocean model of Oberhuber (1993a) is described. The inclusion of snow is shown to be important for obtaining a good simulation of ice thickness in both the Arctic and Antarctic. Thirdly, the coupled ice-ocean model is used to investigate the general circulation of the Artic Ocean and its connection with the North Atlantic. The cyclonic motion of the Atlantic layer within the Arctic is correctly simulated. Fourthly, a sensitivity study of the Arctic mixed-layer circulation is presented.
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32

Elliott, John M. "Simulation of acoustic multipath arrival structure in the Barents Sea". Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/24036.

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33

Kim, Hyun Seok. "Advanced passenger evacuation simulation in a virtual sea-ship environment". Thesis, University of Strathclyde, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417336.

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34

Jafari, Seyed Ahmad. "Software tools for the simulation of oil spills at sea". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.

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This thesis aims at investigating the potentialities of two software tools performing the simulation of the transport and fate of oil spilled at sea: ADIOS2 and the WebGNOME codes, both made freely available by the US NOAA. ADIOS2 gives the oil budget evolution of the spill, that is, it solves the mass balances of the oil present in the different sea compartments. On the other hand, the WebGNOME tool is capable of both solving the oil budget and visualizing the oil slick trajectory. What comes out from the investigation carried out in this thesis is that ADIOS2 is not capable of handling a complete simulation, because it limits the simulation time to 5 days after the start of the spill. Instead, WebGNOME compensates for this lack, allowing to extend the simulation time up to 30 days. By taking a look at the images of the oil slick produced by WebGNOME, it emerges that from day 20 to 30 no major change is seen in the oil slick location. During the first 20 days after the spill, oil beaching occurs on both the northern shoreline and the southern islands of the Santa Barbara Channel, with a total amount of stranded oil equal to 4,800 m3, which accounts for 25 % of the spill. Due to the immediate start of evaporation, 28 % of the oil is transferred from the sea to the atmosphere. At the end of the simulation, floating oil accounts for 6,500 m3, that correspond to 40 % percent; the oil remaining on the sea surface is majorly placed in the outer west side of the Santa Barbara Channel, where it is quite stable, according the last 10 days of the simulation there are negligible changes in the oil budget. It can be claimed that the simulation time of 30 days is sufficient to describe the fate and the transport of the oil slick. In conclusion, the WebGNOME code, which is simple and intuitive to use, requires a limited amount of data, and has short computational times, seems a tool suitable for a preliminary analysis of the consequences of oil spill events at sea.
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35

Brandt, A. D. "Implementation of an SDH simulator using SDR". Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/2467.

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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006.
A Synchronous Digital Hierarchy (SDH) point-to-point bi-directional link was implemented at a base Synchronous Transfer Mode level 1 (STM 1) signal rate. The full STM-1 multiplexer was implemented and the functional code developed to Virtual Container level 4 (VC4) level. The implementation was realized using a Software Defined Radio (SDR) architecture that managed and linked the SDH atomic units into a STM-1 SDH multiplexing structure. These atomic units have been well defined in recommendation G.707 [1]. The functional description of each unit was based on the G.783 [8] recommendation which specifies a library of basic building blocks and set of rules by which these atomic functions should be combined into various functional layers. These layers interconnect to ultimately form a bi-directional path in the SDH network. A SDH Management Sub network (SMS) was implemented using a graphical user interface to perform a monitoring function for the bi-directional link.
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36

Fabbroni, Nicoletta <1979&gt. "Numerical simulations of passive tracers dispersion in the sea". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1733/1/Fabbroni_Nicoletta_Tesi.pdf.

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37

Fabbroni, Nicoletta <1979&gt. "Numerical simulations of passive tracers dispersion in the sea". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1733/.

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38

Li, Ching-Chung. "A numerical simulation of seasonal circulation in the South China Sea". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA283701.

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39

Isleifson, Dustin. "Simulation and measurement techniques for microwave remote sensing of sea ice". IEEE, 2010. http://hdl.handle.net/1993/4812.

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This dissertation presents new research into the study of simulation and measurement techniques for microwave remote sensing of sea ice. We have embarked on a major study of the microwave propagation and scattering properties of sea ice in an attempt to link the physics of the sea ice medium to experimentally obtained concomitant scatterometer measurements. During our fieldwork, we studied the polarimetric backscattering response of sea ice, focusing on newly-formed sea ice under a large assortment of surface coverage. Polarimetric backscattering results and physical data for 40 stations during the fall freeze-up of 2003, 2006, and 2007 are presented. Analysis of the co-polarization correlation coefficient showed its sensitivity to sea ice thickness and surface coverage and resulted in a statistically significant separation of ice thickness into two regimes: ice less than 6 cm thick and ice greater than 8 cm thick. A case study quantified the backscatter of snow-infiltrated frost fl owers on new sea ice, showing that the presence of the frost flowers enhanced the backscatter by more than 6 dB. In our simulation work, an efficient method for simulating scattering from objects in multi-layered media was incorporated into a scattered-field formulation of the FVTD method. A total-field 1D-FDTD solution to the plane-wave propagation through multi-layered meda was used as a source. The method was validated for a TE-polarized incident-field through comparisons with other numerical techniques involving examples of scattering from canonically-shaped objects. Methods for homogenization of inhomogeneous media were developed and validated using well-known dielectric mixture models. A Monte Carlo Method for simulating scattering from statistically rough surfaces was developed and was validated through favorable comparison with the SPM method for rough surface scattering. Finally, we presented a new Monte Carlo Method for simulating sea ice remote sensing that utilized the framework of the FVTD method for scattering simulations. The modeling process was driven by actual physical measurements of sea ice, wherein dielectric and physics-based modeling techniques were employed. The method was demonstrated through a series of case studies where the scattering from newly-formed sea ice was simulated using a TE-polarized incident- eld. Good agreement between experimental scatterometer measurements and simulated results was obtained for co-polarized returns, whereas cross-polarized results indicated that more depolarizing features must be taken into account.
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40

Gassot, Oriane. "Imagerie SAR du régolithe d'un astéroïde : simulation et traitement des données". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALY016.

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Les radars pénétrant sont des instruments embarqués à bord de multiples missions spatiales depuis plusieurs années. En mettant à profit des observations obtenues depuis différentes orbites séparées spatialement, ils peuvent mener à l’utilisation de techniques de tomographie radar en 3D afin d’imager la structure interne de corps planétaires, notamment des astéroïdes, et améliorer les modèles de formations et d’évolution des astéroïdes. Cependant, même si les radars à synthèse d'ouverture (SAR) spatiaux sont classiques afin de détecter et reconstruire des structures planétaires, pour une telle étude effectuée à quelques kilomètres d’un astéroïde, la taille, la vitesse de rotation et au final la géométrie d’observation elle-même remets en question les hypothèses habituellement formulées pour l'observation de la Terre. De plus, afin d’atteindre la résolution métrique nécessaire afin d'observer des astéroïdes kilométriques, le radar doit être à très large bande (UWB) en range et en doppler, ce qui remets également en cause les modèles de synthèse SAR. Puisque les performances du radar, et donc le retour scientifique de la mission, dépendent de la géométrie d’observation et de la configuration du radar, des simulations du signal radar et de la synthèse SAR dans la géométrie d’un petit corps doivent être mis en place. Le but de ma thèse est d'étudier les performances du radar UWB HFR, développé afin d’étudier les petits corps avec des fréquences allant de 300 à 800 MHz, en étudiant les retours du radar.En créant dans un premier temps des modèles numériques de terrains réalistes d’astéroïdes, plusieurs modèles de diffusions ont été étudiés afin de sélectionner le modèle le plus apte à modéliser le champ réfléchi par la surface d’un astéroïde. L’approximation de Kirchhoff (KA) a été sélectionnée et appliquée sur les modèles de terrain créés, et a permis de construire des images SAR qui localisent correctement le terrain simulé, et qui différencient les zones rugueuses des terrains des zones plus planes. Ensuite, l’approximation de Born (BA) a été sélectionnée afin de modéliser le champ réfléchi par la sous-surface d’un astéroïde, permettant de construire des images SAR qui localisent correctement une inclusion enfouie sous la surface. Avec une géométrie d’observation multipass, des algorithmes de tomographie ont été appliqués à partir des résultats obtenus avec BA, afin d’améliorer leur résolution dans la troisième dimension de l’espace, ainsi que la précision de la localisation de la cible enfouie. Enfin, l’étude des performances de la diffusion UWB a permis d’évaluer que, contrairement à ce qui était pressenti, la diffusion UWB n’entraine qu’une dégradation limitée de la résolution en range, et en azimuth
In recent years, surface-penetrating radars were part of several space missions dedicated to study the bodies of the solar system. These radars, associated with repeat-pass observations and processing, can lead to 3D radar tomography, which results in 3D imagery of the first tens of meters of the sub-surface of planetary bodies. This technique can be used to better understand and model the formation processes and post-accretion evolution of asteroids. However, even though spaceborne SAR is a classical technique used for the detection and reconstruction of planetary structures, the small body geometry of observation reconsiders the hypotheses usually formulated for Earth observation. Furthermore, in order to achieve the metric-resolution necessary to study kilometric-sized asteroids with sufficient precision, the radar has to be ultra-wideband in range and in Doppler, which also question the SAR synthesis models established for narrow band signals. As the radar geometry of study and configuration drives the instrument performance, and thus the mission science return, simulation of the radar signal and the SAR synthesis needs to be developed while taking into account the specificity of the small body geometry. Thus, my thesis aims at assessing the performances of the UWB SAR HFR, which is dedicated to the study of small bodies, with frequencies ranging from 300 to 800 MHz, by simulating the radar's return.By creating firsly realistic asteroid digital terrain models (DTM), several surface scattering models were studied in order to select the model most suited to simulate the field scattered by the surface of an asteroid. The Kirchhoff Approximation (KA) was selected and applied on the generated DTM, and was used to build SAR images which correctly locate the DTM studied, and which differenciate the terrain’s rough areas from the smooth ones. Then, the Born Approximation (BA) was selected to model the field reflected by the asteroid subsurface and was found out to correctly locate an inclusion below the surface of an asteroid. With a multipass geometry, tomography algortihms were applied to the BA results in order to improve the resolution of the results in the third dimension of space, as well as the precision of the localisation of the inclusion. Finally, the performances of UWB scattering were studied, and, unlike what was foreseen, UWB scattering generates only a small degradation of the resolution in range and in azimuth
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41

Gustafsson, Hanna, e Sofie Eskilsson. "Simulating ADS-B and CPDLC messages with SDR". Thesis, Linköpings universitet, Institutionen för datavetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-166587.

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Several studies have shown insufficient security in air traffic communication. The increase in air traffic in recent years also increases the need for improved security. CPDLC is used to communicate in text over the data link and ADS-B determines the position of an aircraft. These techniques are looked upon and simulated in the thesis. By proving that ADS-B and CPDLC messages can be transmitted and received with cheap and easy access equipment we want to show the simplicity in performing an attack. The thesis state a foundation to simulate attacks in the future so further work concerning the lack of security can be done.
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42

Nobre, Marcelo Henrique Ramalho. "An?lise de desempenho baseada em simula??o de redes WirelessHART". Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15367.

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Made available in DSpace on 2014-12-17T14:55:51Z (GMT). No. of bitstreams: 1 MarceloHRN_DISSERT.pdf: 1910960 bytes, checksum: 696b69a0c65216fcf9b33e58073b32ab (MD5) Previous issue date: 2012-08-05
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
This dissertation describes the implementation of a WirelessHART networks simulation module for the Network Simulator 3, aiming for the acceptance of both on the present context of networks research and industry. For validating the module were imeplemented tests for attenuation, packet error rate, information transfer success rate and battery duration per station
Esta disserta??o descreve a implementa??o de um m?dulo de simula??o para redes WirelessHART, utilizando o simulador de redes Network Simulator 3, tendo em vista a aceita??o que ambos possuem no atual contexto de pesquisa e na ind?stria. Para valida??o do m?dulo foram implementados testes quanto a atenua??o dos sinais transmitidos, probabilidade de perda pacotes (Packet Error Rate PER), probabilidade de que uma informa??o produzida seja recebida no destino e dura??o da bateria nas esta??es
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43

Kuny, Silvia [Verfasser], e S. [Akademischer Betreuer] Hinz. "Detection of Building Damages in High Resolution SAR Images based on SAR Simulation / Silvia Kuny ; Betreuer: S. Hinz". Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/123507238X/34.

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44

Weiss, Patrice. "Ein Modell zur Simulation der transienten Vorgänge einer Asynchronlinearmaschine Parametrierung am Beispiel eines Wirbelstromläufers /". [S.l.] : [s.n.], 2006. http://se6.kobv.de:8000/btu/volltexte/2006/17.

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45

Yannaccone, John A. "Numerical simulation of the effects of sea level rise on estuarine processes". Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/50072.

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The increasing concentration of carbon monoxide and other gases in the earth’s atmosphere is expected to cause temperatures on earth to increase. This condition, known as the greenhouse effect, could cause the sea level to rise due to the partial melting of the polar icecaps and the thermal expansion of the oceans. Such a rise in the sea level would affect the tides, currents, and sediment and salinity distributions within estuaries. To see the nature of these effects, a parametric study was performed on the Rappahannock River in Virginia with a two-dimensional, laterally averaged, time-dependent numerical model which simulates the movement of water and suspended sediment in the estuary. The model is a systematic sequence of mathematical procedures derived from the mass-balance equation and the equation of motion. These equations are solved through an explicit finite difference scheme. The astronomical tide, the increased height of the sea level due to the greenhouse effect and the additional tidal height due to a storm surge form the boundary conditions at the mouth of the river. Freshwater streamflows constitute the boundary condition at the upstream end of the estuary. A frequency analysis is performed for both the freshwater streamflows and the tidal heights. A procedure is developed which allows one to calculate the return period for various combinations of streamflow and tidal height. The results from each run of the estuary model are reviewed to study the tidal hydraulics and the longitudinal and vertical distributions of the sediment and salinity with and without the sea level rise.
Master of Science
incomplete_metadata
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46

Obino, Rodrigo S. "Simulation of the Bohai Sea circulation and theromohaline structure using COHERENS model". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FObino.pdf.

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47

Susin, Marcos José. "Estudo e desenvolvimento de um atuador planar de armadura sem núcleo ferromagnético". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/150579.

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Este trabalho apresenta a proposta de topologia para um atuador planar sem núcleo ferromagnético na armadura, sua análise teórica em termos de forças de tração que nele atuam, seu desenvolvimento e resultados teóricos e experimentais obtidos como base em um protótipo construído. O atuador planar tem características inovadoras: uma armadura estacionária sem ferro com enrolamentos ortogonais e dois carros acoplados magneticamente um ao outro com quatro ímãs permanentes de NdFeB de alto produto energético. A armadura desse estator é composta por enrolamentos planares multifases colocados de tal maneira que dois enrolamentos ortogonais independentes são produzidos e assim definem duas forças de propulsão ortogonais. Cada carro possui uma culatra de aço que suporta os ímãs permanentes e que está ligada a uma estrutura de suspensão mecânica para permitir o movimento bidirecional sobre a área definida pela armadura. Esse tipo de atuador pode ser usado em aplicações que requerem o movimento em qualquer direção ao longo de um plano. O protótipo desenvolvido neste trabalho foi testado com a finalidade de validar suas características estáticas de operação com relação à análise numérica e o modelo analítico. Os valores de densidade de fluxo magnético no entreferro e de força planar de propulsão, obtidos através de ensaios, apresentaram uma boa aproximação em relação aos valores obtidos através da simulação numérica e do modelo analítico. Para os ensaios de força normal este trabalho preocupou-se em analisar numérica e experimentalmente os resultados, que também apresentaram valores convergentes e satisfatórios para os itens propostos. Para os ensaios do atuador planar com regulagem de entreferro de 12 mm e 24 mm foram encontradas sensibilidades médias da força planar de propulsão de 7,19 N/A e 4,13 N/A respectivamente.
This work presents a proposal of topology of a planar actuator with an ironless armature core, its theoretical analysis in terms of the driving forces that acting on the actuator, its development, the theoretical and experimental results obtained for an implemented prototype. Such planar actuator has innovative features: a stationary and ironless armature core with orthogonal planar windings and two cars magnetically coupled to each other by means of four high energy-product NdFeB permanent magnets. The stator of the actuator comprehends an ironless core with two sets of multiphase windings placed in such a way that two independent orthogonal windings form the armature in a way that allows the yielding of two orthogonal propulsion forces. Each car has a back iron which supports two permanent magnets and is supported by a suspension structure to allow bidirectional movement of the coupled cars. This type of actuator can be used in applications that require the movement in any direction over a plane. The prototype of this study was tested in order to validate their static characteristics of operation with respect to the numerical analysis and the analytical model. The values of magnetic flux density in the air gap and the planar propulsion force obtained through testing, showed a good agreement with the values obtained by numerical simulation and analytical model. The normal force tests showed good agreement with the results of the numerical analysis. The tests of planar actuator with air gaps of 12 mm and 24 mm were found to produce an average sensitivity of the planar propulsion force of 7.19 N/A and 4.13 N/A respectively.
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48

Fischer, Albert S. (Albert Sok). "The upper ocean response to the monsoon in the Arabian Sea". Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/58365.

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Thesis (Ph.D.)--Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences and the Woods Hole Oceanographic Institution), 2000.
Includes bibliographical references (p. 217-222).
Estimation of the upper ocean heat budget from one year of observations at a moored array in the north central Arabian Sea shows a rough balance between the horizontal advection and time change in heat when the one-dimensional balance between the surface heat flux and oceanic heat content breaks down. The two major episodes of horizontal advection, during the early northeast (NE) and late southwest (SW) monsoon seasons, are both associated with the propagation of mesoscale eddies. During the NE monsoon, the heat fluxes within the mixed layer are not significantly different from zero, and the large heat flux comes from advected changes in the thermocline depth. During the SW monsoon a coastal filament exports recently upwelled water from the Omani coast to the site of the array, 600 km offshore. Altimetry shows mildly elevated levels of surface eddy kinetic energy along the Arabian coast during the SW monsoon, suggesting that such offshore transport may be an important component of the Arabian Sea heat budget. The sea surface temperature (SST) and mixed layer depth are observed to respond to high frequency (HF, diurnal to atmospheric synoptic time scales) variability in the surface heat flux and wind stress. The rectified effect of this HF forcing is investigated in a three-dimensional reduced gravity thermodynamic model of the Arabian Sea and Indian Ocean. Both the HF heat and wind forcing act locally to increase vertical mixing in the model, reducing the SST. Interactions between the local response to the surface forcing, Ekman divergences, and remotely propagated signals in the model can reverse this, generating greater SSTs under HF forcing, particularly at low latitudes. The annual mean SST, however, is lowered under HF forcing, changing the balance between the net surface heat flux (which is dependent on the SST) and the meridional heat flux in the model. A suite of experiments with one-dimensional upper ocean models with different representations of vertical mixing processes suggests that the rectified effect of the diurnal heating cycle is dependent on the model, and overstated in the formulation used in the three-dimensional model.
by Albert Sok Fischer.
Ph.D.
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49

Romero, Cindy G. "High Resolution Simulation of Synthetic Aperture Radar Imaging". DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/345.

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The goal of this Master’s thesis is to develop a more realistic simulation of Synthetic Aperture Radar (SAR) that has the ability to image detailed targets, and that can be used for Automatic Target Recognition (ATR). This thesis project is part of ongoing SAR ATR research at California Polytechnic State University (Cal Poly) sponsored by Raytheon Space & Airborne Systems and supervised by Dr. John Saghri. SAR is a form of radar that takes advantage of the forward motion of an antenna mounted on a moving platform (such as an airplane or spacecraft) to synthetically produce the effect of a longer antenna. Since most SAR images used for military ATR are classified and not available to the general public, all academic research to date on ATR has been limited to a small data set of Moving and Stationary Target Acquisition and Recognition Radar (MSTAR) images. Due to the unavailability of radar equipment or a greater range of SAR data, it has been necessary to create a SAR image generation scheme in which the parameters of the radar platform can be directly modified and controlled to be used for ATR applications. This thesis project focuses on making several improvements to Matthew Schlutz’s ‘Synthetic Aperture Radar Imaging Simulated in Matlab’ thesis. First, the simulation is optimized by porting the antenna pattern and echo generator from Matlab to C++, and the efficiency of the code is improved to reduced processing time. A three-dimensional (3-D) graphics application called Blender is used to create and position the target models in the scene imaged by the radar platform and to give altitude, target range (range of closest approach from the platform to the center area of the target) and elevation angle information to the radar platform. Blender allows the user to take pictures of the target as seen from the radar platform, and outputs range information from the radar platform plane to each point in the image. One of the major advantages of using Blender is that it also outputs range and reflectivity information about each pixel in the image. This is a significant characteristic that was hardcoded in the previous theses, making those simulations less realistic. For this thesis project, once the target scene is created in Blender, an image is rendered and saved as an OpenEXR file. The image is rendered in orthographic mode, which is a form of projection whereby the target plane is parallel with the projection plane. This parameter means that the simulation cannot image point targets that appear and disappear during the platform motion. The echo generation program then uses the range and reflectivity obtained from the OpenEXR file, the optimized antenna pattern, and several other user defined parameters to create the echo (received signal). Once the echo is created in the echo generation program, it is then read into Matlab in order for it to go through the Range Doppler Algorithm (RDA) and then output the final SAR image.
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Sara, Barghi. "Water Management Modelling in the Simulation of Water Systems in Coastal Communities". Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24364.

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It is no longer a question of scientific debate that research declares our climate is changing. One of the most important and visible impacts of this phenomenon is sea level rise which has impacts on coastal cities and island communities. Sea level rise also magnifies storm surges which can have severely damaging impacts on different human made infrastructure facilities near the shorelines in coastal zones. In this research we are concerned about the proximity of water systems as one of the most vulnerable infrastructures in the coastal zones because of the impact of stormwater combining with sewage water. In Canada, the government has plans to address these issues, but to date, there needs to be further attention to stormwater management in coastal zones across the country. This research discusses the impacts of severe environmental events, e.g., hurricanes and storm surge, on the water systems of selected coastal communities in Canada. The purpose of this research is to model coastal zone water systems using the open source StormWater Management Modelling (SWMM) software in order to manage stormwater and system response to storms and storm surge on water treatment plants in these areas. Arichat on Isle Madame, Cape Breton, one of the most sensitive coastal zones in Canada, is the focal point case study for this research as part of the C-Change International Community-University Research Alliance (ICURA) 2009-2015 project.
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