This thesis tests a technique based on objectively identified tropical cloud regimes, in which some cloud characteristics are extrapolated from a single site in the tropics to the entire tropics. Information on cloud top pressure, cloud optical thickness and total cloud cover from 1985-2000 has been derived from the ISCCP D1 data set and has been used to create maps of tropical cloud regimes and maps of total cloud cover over the tropics. The distribution and characteristics of the tropical cloud regimes has been discussed after which total cloud cover values were extrapolated to the cloud regimes over the tropics. After a qualitative and quantitative assessment was used to evaluate the success of the extrapolating method, it was found that the method worked especially well for time averaged extrapolated data sets using the median values of total cloud cover values. / I detta magisterexamensarbete testas en metod som baseras på objektivt framtagna molnregimer, där några molnegenskaper extrapoleras från en plats i tropikerna till resten av tropikerna. Informationen om molntoppstrycket, molnens optiska djup och det totala molntäcket från 1985-2000 har hämtats från ISCCP D1 data set och har använts till att skapa kartor för tropiska molnregimer och för det totala molntäcket över tropikerna. Distributionen och egenskaperna av de tropiska molnregimerna har diskuterats och användes sedan för att extrapolera det totala molntäcket över tropikerna. En kvalitativ och kvantitativ undersökning användes för att utvärdera framgångarna med extrapoleringsmetoden. Det framkom att metoden fungerade särskilt bra för extrapolerade data set med median totala molntäcksvärden över längre tidsperioder.

Approved for public release; distribution is unlimited / Image navigation is critical to the effective use of digital imagery for meteorological and oceanographic studies. This thesis reviews various methods used to navigate imagery to the earth and investigates the accuracy of the Naval Postgraduate School (NPS) model. An explanation of how the NPS navigation process works is included for completeness. Results from 2 2 separate runs of the NPS model are studied. / http://archive.org/details/accuracyofsatell00beth / Captain, United States Marine Corps

A novel continuous low-thrust fuel-efficient model predictive control strategy for multi-satellite formations flying in low earth orbit is presented. State prediction relies on a full nonlinear relative motion model, based on quasi-nonsingular relative orbital elements, including earth oblateness effects and, through state augmentation, differential drag. The optimal control problem is specically designed to incorporate latest theoretical results concerning maneuver optimality in the state-space, yielding to a sensible total delta-V reduction, while assuring feasibility and stability though imposition of a Lyapunov constraint. The controller is particularly suitable for networked architectures since it exploits the predictive strategy and the dynamics knowledge to provide robustness against feedback losses and delays. The Networked MPC is validated through real missions simulation scenarios using a high-fidelity orbital propagator which accounts for high-order geopotential, solar radiation pressure, atmospheric drag and third-body effects.

Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Due to the direct magnetic connection of the high-latitude ionosphere to the outer magnetosphere, a great deal of knowledge of the physics and properties of magnetospheric regions and the fundamental plasma processes operating within them can be learned from studying low-altitude particle measurements. In this thesis the temporal and spatial aspects of the low-altitude auroral particle precipitation are investigated using a unique set of particle flux observations from two Defense Meteorological Satellite Program (DMSP) spacecraft in the same orbit but with varying time separation. Three different topics are investigated in this study: auroral stability, the accuracy of the Newell-Meng criteria for region identification, and the relative importance of various magnetopause reconnection models. In the first part the prevalent timescales and spatial dimensions of low-altitude auroral formations are examined using both electron and ion data. It is found that spatial scales larger than 50-100 km are stable for up to 1.5 minutes, while smaller size features vary more rapidly. In the second topic we explore quantitative and qualitative aspects of the Newell-Meng criteria. The flexibility and limitations of the numerical values used are examined with case and statistical studies; all but one are found to be sufficiently robust. Additionally, an expansion of the criteria to include a distinction between open and closed magnetic field line geometries is considered. The last part concentrates on the evaluation of currently proposed models of magnetopause reconnection, based on a case study of ion and electron low-altitude particle reconnection signatures. We conclude that a unique combination of the multiple x-line and bursty single x-line reconnection models is required for a full interpretation of the data. This scenario also provides a comprehensive mechanism for the formation of the low-latitude boundary layer on both open and closed field lines. Finally, the common conclusion of all three studies is that two-point measurements add considerably to our understanding of the low-altitude auroral environment and thereby, the remote processes governing its dynamics. / 2031-01-01

[pt] Dois dos principais fatores que afetam o desempenho dos sistemas de comunicação sem fio são a ocorrência de chuvas ao longo do percurso de transmissão e a existência de interferências externas. Para garantir um desempenho adequado para o enlace, é usual estabelecer limites para as percentagens de tempo durante as quais o desempenho do sistema pode ficar abaixo de alguns níveis pré-estabelecidos. importante que, tanto a degradação de desempenho provocada pela chuva quanto aquela devida às interferências externas sejam tais que as restrições de desempenho sejam atendidas. A degradação devida a chuvas é usualmente considerada no dimensionamento do enlace, uma vez que os modelos matemáticos para a atenuação por chuvas são amplamente conhecidos. No caso de interferências externas, a degradação por elas causada é limitada através do estabelecimento de restrições ao comportamento estatístico das potências dos sinais interferentes. Estas restrições, atualmente em estudo no âmbito da União Internacional de Telecomunicações, devem ser tais que, independentemente das características específicas do sistema interferente considerado, as condições de desempenho requeridas para o enlace sejam satisfeitas. O presente trabalho define um problema de otimização com restrições, cuja solução permite estabelecer as condições a serem impostas ao comportamento estatístico das potências dos sinais interferentes presentes em um enlace. / [en] Two of the main factors that affect the performance of wireless communication systems are fading due to rain and interfering signals that reach the receiver. To guarantee an adequate communication link performance, it is usual to limit the percentages of time during which the system performance may be below certain predefined levels. It is important that performance degradation due to both rain and external interferences be such that these performance constraints are met. Degradation due to rain is usually considered in the communication link design, as mathematical models for rain attenuation are widely known. For external interferences, degradation is usually limited by establishing constraints to the statistical behaviour of the interfering signal power. These constraints should be such that, independently of the specific characteristics of the considered interfering system, link performance objectives can be met. Studies aiming the definition of adequate constraints are currently being developed within the International Telecommunication Union. This dissertation defines a constrained optimization problem that allows for the definition of the constraints to be satisfied by the statistical behaviour of the interfering signal power so that link performance are met.

Este trabalho apresenta o desenvolvimento de um equipamento para testes eletrônicos, GSE (Ground Support Equipment), em nível de sistema e subsistema do imageador multiespectral (MUX) do satélite CBERS3&4, a primeira câmera espacial desenvolvida no país. O projeto foi realizado com base em um modelo de referência para o desenvolvimento de produtos mecatrônicos. O GSE utiliza instrumentação virtual, um banco óptico e outros equipamentos controlados por computador e integrados por uma eletrônica própria para testar todos os requisitos funcionais do subsistema. Além disso, é capaz de simular outros subsistemas do satélite que possuam interface com a câmera MUX, tais como o DDR (Digital Data Recorder), OBDH (On-Board Data Handler) e o EPSS (Eletrical Power Supply Subsystem). Como resultado, este trabalho apresenta os testes realizados pelo equipamento desenvolvido, ressaltando sua funcionalidade. / This work presents the development of an equipment for electronic tests, GSE (Ground Support Equipment), in system and subsytem levels of the multispectral imager from CBERS3&4 satellite, the first camera for space applications developed in the country. This project was developed using a reference model for mechatronic products development. GSE utilizes virtual instrumentation, an optical bench and other equipments controled by computer and integrated by its own electronics to test all subsystem functional requirements. Besides, GSE is capable to simulate all others satellite subsystems which share interfaces with MUX, such as DDR (Digital Data Recorder), OBDH (On-Board Data Handler) and EPSS (Eletrical Power Supply Subsystem). As a result, this work presents the tests accomplished by the developed equipment, emphasizing its functionality.

No description available.

La qualité de l’air est un enjeu environnemental majeur de notre société. Cette thèse se focalise sur l’observation depuis l’espace du polluant gazeux majeur, l’ozone troposphérique. Les instruments satellitaires de nouvelle génération permettent de le mesurer journalièrement aux échelles régionales à globale. Cependant, les mesures d’un seul domaine spectral n’amène pas d’information suffisante pour quantifier les concentrations de l’ozone dans la couche limite atmosphérique, où se situe l’air que nous respirons. Le couplage des mesures de multiples domaines spectraux offre un fort potentiel pour mieux caractériser la pollution à l’ozone. La première approche multispectrale à 2 bandes combinant les mesures de l’infrarouge (IR) de IASI et l’ultraviolet (UV) de GOME-2 a été développée au laboratoire LISA, que j’ai intégré dans le cadre de ma thèse. L’objectif de mon travail de thèse est de franchir un pas supplémentaire dans la quantification de la pollution à l’ozone en incluant la bande visible (VIS) de Chappuis, afin de développer un couplage multispectral inédit à trois bandes spectrales UV+VIS+IR. Premièrement, j’ai mis au point une approche pour extraire l’information sur l’ozone des spectres VIS de GOME-2, en sélectionnant les longueurs d’onde affectées majoritairement par l’absorption à l’ozone et rejetant celles avec des absorptions d’autres gaz, ainsi que déterminant les variables d’ajustement conjoint de l’approche (profil vertical d’ozone, albédo de surface, shifts spectraux, etc) et les bases de données nécessaires pour simuler les spectres VIS (albédo de surface, spectroscopie).Ensuite, j’ai mis en œuvre la méthode multispectrale à trois bandes UV+VIS+IR, premièrement sur des observations simulées défilantes de IASI et GOME-2 et géostationnaires de MAGEAQ afin d’estimer l’amélioration en terme de sensibilité et précision, par rapport aux méthodes existantes. Dernièrement, j’ai appliqué l’approche multispectrale à 3 bandes à des observations satellitaires réelles de IASI et GOME-2. Des comparaisons avec d’autres données montrent des meilleures performances des nouvelles observations UV+VIS+IR pour caractériser des évènements de pollution à l’ozone, par rapport à l’approche à 2 bandes / Air quality is a major environmental issue for our society. This PhD thesis focuses on space borne observation of the major gaseous pollutant. Tropospheric ozone. New generation satellite instruments allow measuring it daily at regional to global scales. However, single spectral domain measurements do not provide enough information for quantifying ozone concentrations at the atmospheric boundary layer, where the air we breathe is located. Synergism of measurements from multiple spectral domains offers a great potential for better characterizing ozone pollution. The first 2-band multispectral approach combining infrared (IR) measurements of IASI and the ultraviolet (UV) of GOME-2 was developed at LISA laboratory, where I conducted my thesis. The goal of my thesis is to go a step further in the quantification of ozone pollution by including the visible (VIS) Chappuis band, in order to develop an unprecedented 3-band multispectral synergism UV+VIS+IR. First, I developed a approach for extracting ozone information from GOME-2 VIS spectra, by selecting the wavelengths mostly affected by ozone absorption and rejecting those with absorptions from other gases, as well as determining the joint adjustment variables of the approach (vertical ozone profile, surface albedo, spectral shifts, etc) and the databases needed to simulate the spectra VIS (surface albedo, spectroscopy).Then, I implemented the multispectral method with three bands UV+VIS+IR, first on simulated low-orbit and geostationary observations from respectively IASI and GOME-2 and MAGEAQ to estimate the improvement in terms of sensitivity and precision, as compared to existing methods. Last, I applied the 3-band multispectral approach to real satellite observations of IASI and GOME-2. Comparisons with other data shows enhanced performances of the new UV+VIS+IR observations to characterize ozone pollution events, with respect to the 2-band approach

OBJECTIVE: Tumor necrosis factor-alpha (TNF-α) is a multifunctional proinflammatory cytokine that plays a critical role in mediating inflammatory and immunological responses. TNF-α has been shown to elicit both beneficial and detrimental biological effects by acting through its two receptors, TNFR1/p55 and TNFR2/p75. Previous studies from this laboratory have shown that TNF-TNFR2/p75 signaling plays a critical role in ischemia-induced neovascularization in muscle and heart tissues. However, the role of TNF-TNFR2/p75 signaling in ischemia induced inflammation and muscle regeneration remains to be characterized. METHODS: To evaluate ischemia induced inflammation responses, young wild type (WT) and young TNFR2/p75 knockout (p75KO) mice were subjected to unilateral hind limb ischemia (HLI) surgery. Operated hind limb tissue samples were collected at 1, 3, 7, and 10 days post-HLI surgery and studied for neutrophil (myeloperoxidase-1 positive cells) and macrophage (F4/80 positive cells) infiltration as well as satellite-cell activation (neural cell adhesion molecule positive cells) at each time point. To determine possible synergistically negative roles of tissue aging and the absence of TNFR2/p75 in either the tissue or bone marrow (BM), two chimeric BM transplantation (BMT) models were generated where young Green Fluorescent Protein (GFP) positive (+) p75KO and WT BM-derived cells were transplanted into adult p75KO mice. HLI surgery was performed one month post-BMT, after confirming complete engraftment of the recipient BM with GFP donor cells. Operated hind limb tissue samples were evaluated up to 28 days post-surgery to examine proliferation and apoptosis of BM-derived cells in ischemic tissue. RESULTS: Ischemia induced significant and long-lasting inflammation associated with a considerable decrease in satellite-cell activation in p75KO muscle tissue 1-10 days post-HLI surgery. For the BMT studies, in adult p75KO with the WT-BMT, proliferative (Ki67+) cells were detected only by day 28 and were exclusively GFP (+), suggesting delayed contribution of young WT-BM cell to adult p75KO ischemic tissue recovery. No GFP (+) young p75KO BM cells survived in adult p75KO tissue. CONCLUSION: The data demonstrate that: (1) ischemia-induced recovery in skeletal muscle tissue is impaired in young p75KO mice; (2) inflammatory responses are significantly increased and long-lasting in p75KO mice; (3) in the absence of TNFR2/p75 signaling, satellite-cell activation is affected in p75KO mice; (4) during post-ischemic recovery, tissue aging combined with decreased/absent TNFR2/p75 signaling may have synergistically negative roles on survival and proliferation in the damaged tissue.

The evolution of software applications from single desktops to sophisticated cloud-based systems is challenging. In particular, applications that involve massive data sets, such as geospatial applications and data science applications are challenging for domain experts who are suddenly constructing these sophisticated code bases. Relatively new software practices, such as Microservice infrastructure and DevOps, give us an opportunity to improve development, maintenance and efficiency for the entire software lifecycle. Microservices and DevOps have become adopted by software developers in the past few years, as they have relieved many of the burdens associated with software evolution. Microservices is an architectural style that structures an application as a collection of services. DevOps is a set of practices that automates the processes between software development and IT teams, in order to build, test, and release software faster and increase reliability. Combined with lightweight virtualization solutions, such as containers, this technology will not only improve response rates in cloud-based solutions but also drastically improve the efficiency of software development. This thesis studies two applications that apply Microservices and DevOps within a domain-specific application. The advantages and disadvantages of Microservices architecture and DevOps are evaluated through the design and development on two different platforms---a batch-based cloud system, and a general purpose cloud environment. / Graduate