Relevant bibliographies by topics / Global attenuation

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers

Academic literature on the topic 'Global attenuation'

Author: Grafiati
Published: 4 June 2021
Last updated: 4 February 2022

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Journal articles on the topic "Global attenuation"

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Dalton, Colleen A., and Göran Ekström. "Global models of surface wave attenuation." Journal of Geophysical Research: Solid Earth 111, B5 (May 2006): n/a. http://dx.doi.org/10.1029/2005jb003997.

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Shiuly, Amit. "Global Attenuation Relationship for Estimating Peak Ground Acceleration." Journal of the Geological Society of India 92, no. 1 (July 2018): 54–58. http://dx.doi.org/10.1007/s12594-018-0952-4.

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Paz, Maria Catarina, Francisco J. Alcalá, and Luís Ribeiro. "Ground Penetrating Radar Attenuation Expressions in Shallow Groundwater Research." Journal of Environmental and Engineering Geophysics 25, no. 1 (March 2020): 153–60. http://dx.doi.org/10.2113/jeeg19-039.

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The electromagnetic-wave attenuation coefficient determines the overall resolution and effective penetration depth of ground penetrating radar (GPR) surveys. Despite this relevance to the design of proper GPR surveys, the attenuation expressions are rarely used in the applied shallow groundwater research (SGR) literature. This work examines the status of the attenuation expressions in SGR. For this, 73 GPR case studies (in 47 papers), including some information concerning the attenuation variables and parameters, were selected to build a database. From these, 18 cases (in 10 papers) provided attenuation expressions and only 11 cases (in 4 papers) used those expressions. Two types of expressions were identified, physically based global ones that try to solve a broad (but not complete) range of environmental and field technical conditions, and non-global ones adapted for specific geological environments and resolution needed. The database analysis showed that both global and non-global expressions were used exclusively in low-loss media to report an attenuation range of 0.1–21.5 dB m −1 by using common antenna frequencies in the 25–900 MHz range. The range of the attenuation expressions validity in SGR is biased because no surveys in variable-loss heterogeneous media and wider antenna frequency intervals could be compiled. The attenuation database generated seeks to improve the design of GPR surveys in SGR.
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Graizer, Vladimir, Erol Kalkan, and Kuo-Wan Lin. "Global Ground Motion Prediction Equation for Shallow Crustal Regions." Earthquake Spectra 29, no. 3 (August 2013): 777–91. http://dx.doi.org/10.1193/1.4000140.

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The Graizer-Kalkan ground-motion prediction equation (GMPE) for peak ground acceleration (PGA) constitutes a series of filters, each of which represents a certain physical phenomenon affecting the radiation of seismic waves from the source. The performance of this GMPE is examined by using about 14,000 records from 245 worldwide shallow crustal events. The recorded data and predictions show an excellent match as far as 100 km from the fault. Beyond 100 km, the data generally show faster attenuation on the order of Rrup−4 due to a relatively low Q (as in the western United States) or slower attenuation on the order of Rrup−1.5 due to a high Q (as in the central and eastern United States). An improved GMPE is developed to account for regional variations in ground motion attenuation. The The new GMPE produces a better match to recorded data up to 500 km from the fault.
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Jiang, Zhong-Ping. "Nonlinear disturbance attenuation with global stability via output feedback." IFAC Proceedings Volumes 32, no. 2 (July 1999): 2440–45. http://dx.doi.org/10.1016/s1474-6670(17)56415-0.

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Berger, G., P. Laugier, J. C. Thalabard, and J. Perrin. "Global Breast Attenuation: Control Group and Benign Breast Diseases." Ultrasonic Imaging 12, no. 1 (January 1990): 47–57. http://dx.doi.org/10.1177/016173469001200104.

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This paper deals with the estimation of the slope of attenuation in human breast tissue. The measurement is done in the reflection mode with a short time Fourier analysis. All important factors such as diffraction effect, tissue depth and specular reflectors are taken into account. A population of 49 normal women shows large inter-individual variations of the attenuation coefficient. A multiple linear regression allows correlation of this variation with the duration of the woman's genital life and pregnancies. A preliminary study is done on 10 benign diffuse breast diseases and shows a weak correlation with the type of the breast: normal or pathological. The utility of the quantification is discussed for one case of large fibrocystic disease.
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Chandrasekar, V., H. Fukatsu, and K. Mubarak. "Global mapping of attenuation at ku- and ka-band." IEEE Transactions on Geoscience and Remote Sensing 41, no. 10 (October 2003): 2166–76. http://dx.doi.org/10.1109/tgrs.2003.815973.

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Berger, G. "Global breast attenuation: Control group and benign breast diseases." Ultrasonic Imaging 12, no. 1 (January 1990): 47–57. http://dx.doi.org/10.1016/0161-7346(90)90220-r.

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Vafeidis, Athanasios T., Mark Schuerch, Claudia Wolff, Tom Spencer, Jan L. Merkens, Jochen Hinkel, Daniel Lincke, Sally Brown, and Robert J. Nicholls. "Water-level attenuation in global-scale assessments of exposure to coastal flooding: a sensitivity analysis." Natural Hazards and Earth System Sciences 19, no. 5 (May 3, 2019): 973–84. http://dx.doi.org/10.5194/nhess-19-973-2019.

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Abstract. This study explores the uncertainty introduced in global assessments of coastal flood exposure and risk when not accounting for water-level attenuation due to land-surface characteristics. We implement a range of plausible water-level attenuation values for characteristic land-cover classes in the flood module of the Dynamic and Integrated Vulnerability Assessment (DIVA) modelling framework and assess the sensitivity of flood exposure and flood risk indicators to differences in attenuation rates. Results show a reduction of up to 44 % in area exposure and even larger reductions in population exposure and expected flood damages when considering water-level attenuation. The reductions vary by country, reflecting the differences in the physical characteristics of the floodplain as well as in the spatial distribution of people and assets in coastal regions. We find that uncertainties related to not accounting for water attenuation in global assessments of flood risk are of similar magnitude to the uncertainties related to the amount of sea-level rise expected over the 21st century. Despite using simplified assumptions to account for the process of water-level attenuation, which depends on numerous factors and their complex interactions, our results strongly suggest that an improved understanding and representation of the temporal and spatial variation of water levels across floodplains is essential for future impact modelling.
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Lam, Bhan, Dongyuan Shi, Valiantsin Belyi, Shulin Wen, Woon-Seng Gan, Kelvin Li, and Irene Lee. "Active Control of Low-Frequency Noise through a Single Top-Hung Window in a Full-Sized Room." Applied Sciences 10, no. 19 (September 29, 2020): 6817. http://dx.doi.org/10.3390/app10196817.

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The push for greater urban sustainability has increased the urgency of the search for noise mitigation solutions that allow for natural ventilation into buildings. Although a viable active noise control (ANC) solution with up to 10 dB of global attenuation between 100 Hz and 1000 Hz was previously developed for an open window, it had limited low-frequency performance below 300 Hz, owing to the small loudspeakers used. To improve the low-frequency attenuation, four passive radiator-based speakers were affixed around the opening of a top-hung ventilation window. The active control performance between 100 Hz and 700 Hz on a single top-hung window in a full-sized mock-up apartment room was examined. Active attenuation came close to the performance of the passive insulation provided by fully closing the window for expressway traffic and motorbike passing noise types. For a jet aircraft flyby, the performance of active attenuation with the window fully opened was similar to that of passive insulation with fully closed windows. In the case of low-frequency compressor noise, active attenuation’s performance was significantly better than the passive insulation. Overall, between 8 dB and 12 dB of active attenuation was achieved directly in front of the window opening, and up to 10.5 dB of attenuation was achieved across the entire room.
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Dissertations / Theses on the topic "Global attenuation"

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FAGUNDES, IGOR FREITAS. "RAIN ATTENUATION PREDICTION FROM GLOBAL WEATHER DATA." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24384@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
A disponibilidade é o parâmetro chave no dimensionamento de sistemas de comunicação. Em sistema via rádio diversos fatores reduzem esta disponibilidade, entre os quais se podem citar o desvanecimento, as atenuações adicionais, as interferências externas e a ocorrência de falhas dos equipamentos. A atenuação por chuvas é o principal fenômeno de atenuação adicional para sistemas que operam em frequências superiores a 10 GHz. A chuva é um fenômeno aleatório que apresenta grande variação no espaço e no tempo. Diversos modelos teóricos e semi-empíricos foram propostos na literatura à medida que crescia a utilização de frequências mais elevadas na faixa de micro-ondas. A principal diferença entre os modelos está na maneira de representar a variação espaço-temporal da chuva e o seu efeito na onda eletromagnética em propagação. No trabalho é investigada a influência de parâmetros meteorológicos de direção e velocidade do vento, e testado o conceito de taxa de precipitação efetiva na modelagem. Dois modelos semi-empíricos são desenvolvidos com base em distribuições cumulativas de atenuação e taxas de precipitação pontuais disponíveis no banco de dados da União Internacional de Telecomunicações (UIT-R). Os testes de comparação demonstram que os modelos obtidos apresentam desempenho superior se comparados aos modelos atualmente recomendados para previsão da atenuação por chuvas. Em outra linha de investigação, foi desenvolvido um modelo estatisticamente consistente para previsão da distribuição da atenuação a partir da representação da distribuição cumulativa complementar da taxa de precipitação. A distribuição cumulativa da atenuação foi obtida a partir da suposição de um relacionamento com significado físico entre a taxa de precipitação e atenuação por chuvas. A comparação dos modelos demonstra que o modelo obtido apresenta resultados comparáveis a modelos de Recomendações do UIT-R.
Availability is the key parameter in the communication systems design. In radio system many factors impact the availability, including fading, additional loss, external interference and equipment availability. The rain attenuation is the main impairments in systems operating at frequencies above 10 GHz. The rain is a random phenomenon that is highly variable in space and time. Several theoretical and semi-empirical models have been proposed in the literature as the growing use of higher frequencies in the microwave range. The main difference between the models is the way to represent the rain variation effect on electromagnetic waves. This work investigates the meteorological parameters direction and speed of wind influence in modeling. Two semi-empirical models are developed based on attenuation and rainfall rates cumulative distributions available at International Telecommunication Union (ITU-R) database. ITU-R testing criteria shows that the obtained models have superior performance compared to currently recommended models for rain attenuation prediction. In another line of investigation, a statistically consistent model to predict attenuation distribution from the complementary cumulative distribution of rainfall rate was developed. The attenuation cumulative distribution was obtained from rainfall rate and rain attenuation physical relationship assumption. ITU-R testing criteria show that the obtained model has results comparable with Recommendations ITU-R models.
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Oliveira, Leuda da Silva [UNESP]. "Estimativa da radiação solar direta na incidência nas partições instantânea, horária e diária a partir da radiação solar global." Universidade Estadual Paulista (UNESP), 2001. http://hdl.handle.net/11449/90720.

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Made available in DSpace on 2014-06-11T19:24:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-03-01Bitstream added on 2014-06-13T19:31:43Z : No. of bitstreams: 1 oliveira_ls_me_fca.pdf: 2019828 bytes, checksum: 8dc8d60acc70b25a1970be06df70ff80 (MD5)
A partir de uma base de dados das radiações solar global e direta na incidência, desenvolveu-se no presente trabalho modelos de estimativas da radiação solar direta da incidência a partir da radiação solar global para as partições de tempo instantânea, horária e diária. Foi também equacionado o coeficiente de atenuação da radiação solar direta ela atmosfera (K) em função do índice de claridade (K). Os modelos foram gerados a partir da função logística modificada de Boltzmann, no período de março/96 a fevereiro/98, e a mensal e anual no período de março/98 a fevereiro/99, para as três partições de , obtendo-se as equações: o j 0, -0,85 2 para a partição mstantanea -* Kb = 1+eKt_O5SO95/OO7455 + 0,85, com R =0,804, II 0,00002-0,89999 2 para a partição horária -* Kb = 1 +eKt_O59228/OIO364 + 0,89999, com R =0,816 e para a partição diária -* K = 1 + et°,0°°8185 + 0,97, com R20,987.Na validação mensal dos modelos, obteve-se uma correlação de Kb em função de K de 95,1% a 98,8% para a partição instantânea; 85,5% a 96,7% para a partição horária, de 74,2% a 96,9% para a partição diária. Na validação anual do modelo obteve-se uma correlação de 97,4% para a partição instantânea, de 98,7% para a partição horária e de 96,9% para a partição diária, sendo que quando se defiuiiu o intervalo de OIn this work it was aimed at to establish the estimation models for direct normal solar irradiance (Kb) in funetion of instantaneous, hourly and daily global radiation (IÇ), as well as to set out the atmospheric attenuation coefficient (K) in function of the clearness index (K) for Botucatu-São Paulo-Brazil. The observed data of I( instantaneous, hourly and daily, were adjusted to a function growth logistic modified of Boltzmann in the period from march /96 to february/98, and the monthly and annual validation was made in the period from march/98 to february/99, with the foilowing results: - for the instantaneous, -* K, = + etO 095)10,07455 + 0,85, with R2=0,804, - for the hourly, -* K = + 0,89999, with R2=0,8 16 and - for the daily, -* = 1 + e ,08185 + 0,97, with R20,987. The atmospheric attenuation coefficient (K) had an exponential behavior in the form: K = 1 1,35.e49t with determination coefficient of 95%.
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Rosa, João Willy Corrêa. "A global study on phase velocity, group velocity and attenuation of Rayleigh waves in the period range 20 to 100 seconds." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/57630.

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Oliveira, Leuda da Silva. "Estimativa da radiação solar direta na incidência nas partições instantânea, horária e diária a partir da radiação solar global /." Botucatu : [s.n.], 2001. http://hdl.handle.net/11449/90720.

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Orientador: João Francisco Escobedo
Banca: Dinival Martins
Banca: Roberto Naves Domingues
Resumo : A partir de uma base de dados das radiações solar global e direta na incidência, desenvolveu-se no presente trabalho modelos de estimativas da radiação solar direta da incidência a partir da radiação solar global para as partições de tempo instantânea, horária e diária. Foi também equacionado o coeficiente de atenuação da radiação solar direta ela atmosfera (K) em função do índice de claridade (K). Os modelos foram gerados a partir da função logística modificada de Boltzmann, no período de março/96 a fevereiro/98, e a mensal e anual no período de março/98 a fevereiro/99, para as três partições de , obtendo-se as equações: o j 0, -0,85 2 para a partição mstantanea -* Kb = 1+eKt_O5SO95/OO7455 + 0,85, com R =0,804, II 0,00002-0,89999 2 para a partição horária -* Kb = 1 +eKt_O59228/OIO364 + 0,89999, com R =0,816 e para a partição diária -* K = 1 + et°,0"°°8185 + 0,97, com R20,987.Na validação mensal dos modelos, obteve-se uma correlação de Kb em função de K de 95,1% a 98,8% para a partição instantânea; 85,5% a 96,7% para a partição horária, de 74,2% a 96,9% para a partição diária. Na validação anual do modelo obteve-se uma correlação de 97,4% para a partição instantânea, de 98,7% para a partição horária e de 96,9% para a partição diária, sendo que quando se defiuiiu o intervalo de OAbstract: In this work it was aimed at to establish the estimation models for direct normal solar irradiance (Kb) in funetion of instantaneous, hourly and daily global radiation (IÇ), as well as to set out the atmospheric attenuation coefficient (K) in function of the clearness index (K) for Botucatu-São Paulo-Brazil. The observed data of I( instantaneous, hourly and daily, were adjusted to a function growth logistic modified of Boltzmann in the period from march /96 to february/98, and the monthly and annual validation was made in the period from march/98 to february/99, with the foilowing results: - for the instantaneous, -* K, = + etO 095)10,07455 + 0,85, with R2=0,804, - for the hourly, -* K = + 0,89999, with R2=0,8 16 and - for the daily, -* = 1 + e ,08185 + 0,97, with R20,987. The atmospheric attenuation coefficient (K) had an exponential behavior in the form: K = 1 1,35.e49t with determination coefficient of 95%.
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Anderson, Monty J. "Active Control of the Human Voice from a Sphere." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5295.

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This work investigates the application of active noise control (ANC) to speech. ANC has had success reducing tonal noise. In this work, that success was extended to noise that is not completely tonal but has some tonal elements such as speech. Limitations such as causality were established on the active control of human speech. An optimal configuration for control actuators was developed for a sphere using a genetic algorithm. The optimal error sensor location was found from exploring the nulls associated with the magnitude of the radiated pressure with reference to the primary pressure field. Both numerically predicted and experimentally validated results for the attenuation of single frequency tones were shown. The differences between the numerically predicted results for attenuation with a sphere present in the pressure field and monopoles in the free-field are also discussed.The attenuation from ANC of both monotone and natural speech is shown and a discussion about the effect of causality on the results is given. The sentence “Joe took father’s shoe bench out” was used for both monotone and natural speech. Over this entire monotone speech sentence, the average attenuation was 8.6 dB with a peak attenuation of 10.6 dB for the syllable “Joe”. Natural speech attenuation was 1.1 dB for the sentence average with a peak attenuation on the syllable “bench” of 2.4 dB. In addition to the lower attenuation values for natural speech, the pressure level for the word “took” was increased by 2.3 dB. Also, the harmonic at 420 Hz in the word “father’s” of monotone speech was reduced globally up to 20 dB. Based on the results of the attenuation of monotone and natural speech, it was concluded that a reasonable amount of attenuation could be achieved on natural speech if its correlation could approach that of monotone speech.
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Locatelli, Bruno. "Services écosystémiques et changement climatique." Habilitation à diriger des recherches, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00931871.

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Ce mémoire d'HDR présente une recherche sur le changement climatique et les services écosystémiques, en particulier ceux des forêts tropicales. Les écosystèmes jouent un rôle important dans l'atténuation du changement climatique (limitation de l'accroissement des gaz à effet de serre dans l'atmosphère) par le biais de la séquestration du carbone. Ils contribuent aussi à l'adaptation de la société (réduction des effets néfastes du changement climatique), mais cette contribution est peu explorée. L'agriculture et les forêts sont fortement liées à l'atténuation et à l'adaptation, en raison de leurs émissions de gaz à effet de serre, leur vulnérabilité et leur place dans les moyens d'existence des populations rurales. Dans ces secteurs, des recherches sont nécessaires pour analyser comment atténuation et adaptation peuvent être mises en oeuvre en synergie, mais les arbitrages entre ces deux approches sont aussi à étudier. Le mémoire introduit le cadre conceptuel utilisé pour étudier les liens entre services écosystémiques et changement climatique (chapitre 2). Il présente l'évolution des questions de recherche sur l'évaluation des services et des instruments associés, comme le Mécanisme de Développement Propre (MDP), les Paiements pour Services Environnementaux (PSE) et les plans d'action nationaux pour l'adaptation (PANA) (chapitre 3). Des recherches conduites ces dernières années sont détaillées dans le chapitre 4, comme des études locales sur l'adaptation ou le développement d'approches pour cartographier les services écosystémiques et leurs relations et évaluer des instruments politiques. Les résultats incluent une analyse de la contribution des écosystèmes à l'adaptation de la société à travers six cas de figure (produits et communautés, arbres et agriculture, bassins versants forestiers, zones côtières, villes, climat régional). Le mémoire présente un projet de recherche sur les transitions de services écosystémiques, leurs moteurs et leurs effets sur la société dans un contexte de changement global (chapitre 5). Finalement le parcours du candidat à l'HDR est détaillé dans le chapitre 6.
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Johnson, Stuart G. "Applications of global seismic tomography and analysis of variational methods for the solution of the linearly attenuating frequency domain wave equation /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9823696.

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Guilbert, Jocelyn. "Caractérisation des structures lithosphériques sous le Nord Tibet et sous le Massif Central à partir des données sismologiques du programme Lithoscope." Phd thesis, Université Joseph Fourier (Grenoble), 1995. http://tel.archives-ouvertes.fr/tel-00721900.

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L'étude des données Lithoscope permet d'étudier les structures profondes de la lithosphère. Trois méthodes ont été développées. La première porte sur l'analyse des ondes converties à l'interface croûte-manteau afin de contraindre les variations d'épaisseur de croûte. La seconde méthode caractérise l'orientation des structures dans le manteau, par la rnesure de l'anisotropie des ondes S. La troisième méthode mesure l'atténuation des milieux échantillonnés à l'aide de deux méthodes d'analyse fréquentielle et temporelle. Ces trois méthodes ont été appliquées aux enregistrements provenant du Nord Tibet, du Massif Central et de l'Abitibi, L'étude des données du plateau tibétain a permis de mettre en évidence des variations latérales très importantes de vitesse et de structure dans la lithosphère. Un saut de Moho de 20km a été observé sans qu'aucune variation de topographie ne soit observable. Ces travaux montrent que les phénomènes de l'équilibrage dans la lithosphère sont lents comparés aux mouvements horizontaux et verticaux. L'étude de l'anisotropie a permis de révéler l'importance de l'extrusion latérale le long de la faille du Kunlun. Les valeurs d'anisotropie obtenues impliquent que les mouvements horizontaux des blocs lithosphériques orientent les minéraux sur des épaisseurs mantelliques supérieures à 260 km. L'étude de l'atténuation sous le Massif Central a permis de constater qu'il existait une bonne corrélation entre les zones atténuantes et ies édifices volcaniques majeurs de cette région. Les valeurs du facteur de qualité obtenues montrent que les perturbations occasionnées par le volcanisme intéressent l'ensemble de la lithosphère mais sur de zones très étroites. Les modé!isations de perturbation thermique dans la croûte montrent de très bonnes corrélations avec les âges des différentes crises volcaniques. L'application systématique de ces trois analyses sur les enregistrements télésismiques du programme Lithoscope a permis de contraindre et de compléter les images de la lithosphère obtenues par la tomographie en vitesse des ondes P.
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Madruga, Ana Gisela Duarte. "Characterization of a global 4G mobile communications network using the commercial aircraft network." Master's thesis, 2019. http://hdl.handle.net/10071/22221.

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The ever increasing demand for high data rates and mobility, at the same time with the lowest latency possible, comes as a motivation and inspiration for the writing of this dissertation. Besides terrestrial networks, another common way to communicate nowadays is via satellite networks; low Earth orbit satellites are the ones closer to the Earth, still, they are 800km away, requiring high energetic consumption. Routes used by commercial air traffic cover great part of the globe, with higher incidence in the most populated areas, namely North America, Europe and Eastern Asia. The main objective of this project is to prove that it would be possible to have a global coverage network or, at least, a network able to fulfil the needs of users located in the most populated regions, where air traffic is denser. Users would be able to communicate to any part of the world; the nearest aircraft gets the signal and, since they are organized as a mesh network, it travels from aircraft to aircraft until it reaches its final destination. LTE frequency bands have a great margin to operate without interfering with the frequencies used in aeronautical radio communication systems, as will be seen in Chapter 3. The work developed shows that the most favourable conditions regarding the maximum distances obtained to establish the communication will be to set up the proposed system using QPSK, a 1.4 MHz channel and transmission frequency should be 737 MHz. Thus, maximum attainable distance in rural scenario is 46.62 km.
A constante procura por taxas de alto débito e mobilidade, aliado à menor latência possível, surgiram como motivação e inspiração para a escrita desta dissertação. Além das redes terrestres, outra forma comum de comunicar nos dias de hoje é recorrendo a redes de satélites; os satélites de baixa órbita são os que estão mais próximo da Terra, no entanto estão a 800km de distância, o que requer um elevado consumo energético. As rotas utilizadas pelos aviões comerciais cobrem grande parte do globo, com maior incidência nas zonas mais povoadas, nomeadamente América do Norte, Europa e Este da Asia. O maior objetivo deste projeto é provar que é possível haver uma rede de cobertura global ou, pelo menos, uma rede capaz de satisfazer as necessidades dos utilizadores localizados nas zonas mais povoadas onde o tráfego aéreo é mais frequente. Os utilizadores poderiam comunicar para qualquer parte do mundo; o avião mais próximo receberia o sinal e, como estes estão organizados numa rede mesh, o sinal viajaria de avião em avião, até chegar ao seu destino. As bandas de frequência usadas no LTE têm uma grande margem para operar sem interferir com as frequências utilizadas nas comunicações na aviação, como será visto no Capítulo 3. O A constante procura por taxas de alto débito e mobilidade, aliado à menor latência possível, surgiram como motivação e inspiração para a escrita desta dissertação. Além das redes terrestres, outra forma comum de comunicar nos dias de hoje é recorrendo a redes de satélites; os satélites de baixa órbita são os que estão mais próximo da Terra, no entanto estão a 800km de distância, o que requer um elevado consumo energético. As rotas utilizadas pelos aviões comerciais cobrem grande parte do globo, com maior incidência nas zonas mais povoadas, nomeadamente América do Norte, Europa e Este da Asia. O maior objetivo deste projeto é provar que é possível haver uma rede de cobertura global ou, pelo menos, uma rede capaz de satisfazer as necessidades dos utilizadores localizados nas zonas mais povoadas onde o tráfego aéreo é mais frequente. Os utilizadores poderiam comunicar para qualquer parte do mundo; o avião mais próximo receberia o sinal e, como estes estão organizados numa rede mesh, o sinal viajaria de avião em avião, até chegar ao seu destino. As bandas de frequência usadas no LTE têm uma grande margem para operar sem interferir com as frequências utilizadas nas comunicações na aviação, como será visto no Capítulo 3. O trabalho desenvolvido mostra-nos que as condições mais favoráveis, no que toca a distâncias máximas obtidas para estabelecer a comunicação, serão montar o sistema proposto utilizando QPSK, um canal de 1.4 MHz e cuja frequência de transmissão seja 737 MHz. Assim, consegue-se obter uma distância máxima de transmissão em ambiente rural de 46.62 km.rabalho desenvolvido mostra-nos que as condições mais favoráveis, no que toca a distâncias máximas obtidas para estabelecer a comunicação, serão montar o sistema proposto utilizando QPSK, um canal de 1.4 MHz e cuja frequência de transmissão seja 737 MHz. Assim, consegue-se obter uma distância máxima de transmissão em ambiente rural de 46.62 km.
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Book chapters on the topic "Global attenuation"

1

Weik, Martin H. "global attenuation-rate characteristic." In Computer Science and Communications Dictionary, 682. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_7971.

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2

Weik, Martin H. "fiber global attenuation rate characteristic." In Computer Science and Communications Dictionary, 581. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_6898.

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Weik, Martin H. "optical fiber global attenuation-rate characteristic." In Computer Science and Communications Dictionary, 1170. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_13019.

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Weik, Martin H. "Fiber optic global attenuation-rate characteristic." In Computer Science and Communications Dictionary, 589. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_6957.

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5

Tselentis, G.-Akis. "Intrinsic and Scattering Seismic Attenuation in W. Greece." In Q of the Earth: Global, Regional, and Laboratory Studies, 703–12. Basel: Birkhäuser Basel, 1998. http://dx.doi.org/10.1007/978-3-0348-8711-3_22.

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Der, Zoltan A. "High-frequency P- and S-wave Attenuation in the Earth." In Q of the Earth: Global, Regional, and Laboratory Studies, 273–310. Basel: Birkhäuser Basel, 1998. http://dx.doi.org/10.1007/978-3-0348-8711-3_4.

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Romanowicz, Barbara. "Attenuation Tomography of the Earth’s Mantle: A Review of Current Status." In Q of the Earth: Global, Regional, and Laboratory Studies, 257–72. Basel: Birkhäuser Basel, 1998. http://dx.doi.org/10.1007/978-3-0348-8711-3_3.

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Romanowicz, Barbara, and Joseph J. Durek. "Seismological constraints on attenuation in the Earth: A review." In Earth's Deep Interior: Mineral Physics and Tomography From the Atomic to the Global Scale, 161–79. Washington, D. C.: American Geophysical Union, 2000. http://dx.doi.org/10.1029/gm117p0161.

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Matheney, Michael P., and Robert L. Nowack. "Seismic Attenuation Computed from GLIMPCE Reflection Data and Comparison with Refraction Results." In Q of the Earth: Global, Regional, and Laboratory Studies, 539–61. Basel: Birkhäuser Basel, 1998. http://dx.doi.org/10.1007/978-3-0348-8711-3_14.

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Jackson, Ian. "Laboratory measurement of seismic wave dispersion and attenuation: Recent progress." In Earth's Deep Interior: Mineral Physics and Tomography From the Atomic to the Global Scale, 265–89. Washington, D. C.: American Geophysical Union, 2000. http://dx.doi.org/10.1029/gm117p0265.

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Conference papers on the topic "Global attenuation"

1

D'Cruz, Jonathan. "Global vibration attenuation with multiple piezoceramic actuators." In 36th Structures, Structural Dynamics and Materials Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1995. http://dx.doi.org/10.2514/6.1995-1133.

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He Wang, Ming Zhao, and M. C. Reed. "Optimal Adaptive Uplink Attenuation Algorithms for WCDMA Femtocell." In 2011 IEEE Global Communications Conference (GLOBECOM 2011). IEEE, 2011. http://dx.doi.org/10.1109/glocom.2011.6133726.

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Suzuki, Daiki, and Kazuhiro Kondo. "Application of ANC for singing voice attenuation." In 2014 IEEE 3rd Global Conference on Consumer Electronics (GCCE). IEEE, 2014. http://dx.doi.org/10.1109/gcce.2014.7031140.

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Norain Malik, Arafa Omer, Mohammad Kamrul Hasan, Rashid A. Saeed, Rania A. Mokhtar, Siti Norul Huda Sheikh Abdullah, Musse Mohamud Ahmed, and Shayla Islam. "Rain Attenuation Models for Mobile Satellite Communication in Sudan." In 2020 Global Conference on Wireless and Optical Technologies (GCWOT). IEEE, 2020. http://dx.doi.org/10.1109/gcwot49901.2020.9391615.

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Matsuura, Keisuke, and Kazuhiro Kondo. "Towards a singing voice attenuation system using active noise control." In 2015 IEEE 4th Global Conference on Consumer Electronics (GCCE). IEEE, 2015. http://dx.doi.org/10.1109/gcce.2015.7398631.

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Liu, Jie, Guohua Zhang, Chuntao Yang, Chunyue Cheng, and Ting Chen. "Attenuation measurement system in the frequency range of 140GHz–220GHz." In 2012 5th Global Symposium on Millimeter Waves (GSMM 2012). IEEE, 2012. http://dx.doi.org/10.1109/gsmm.2012.6314069.

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Boluda-Ruiz, Ruben, Pedro Rico-Pinazo, Beatriz Castillo-Vazquez, Antonio Garcia-Zambrana, and Khalid Qaraqe. "Time-Dispersion and Signal Attenuation Analysis of Underwater Optical Wireless Communication Links." In GLOBECOM 2019 - 2019 IEEE Global Communications Conference. IEEE, 2019. http://dx.doi.org/10.1109/globecom38437.2019.9013573.

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Mohsen, Mohanad, and David W. Matolak. "Vegetation Attenuation for Several Evergreen Shrubs at 31 and 5 GHz." In 2018 11th Global Symposium on Millimeter Waves (GSMM). IEEE, 2018. http://dx.doi.org/10.1109/gsmm.2018.8439189.

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Zhang, Yushu, and Hongbo Lin. "The adaptive complex shock diffusion for seismic random noise attenuation." In 2017 IEEE Global Conference on Signal and Information Processing (GlobalSIP). IEEE, 2017. http://dx.doi.org/10.1109/globalsip.2017.8308659.

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Suarez, Rodolfo, Jose Alvarez-Ramirez, and Mario Sznaier. "Global stabilization and L2 disturbance attenuation for linear systems with bounded controls." In 1997 European Control Conference (ECC). IEEE, 1997. http://dx.doi.org/10.23919/ecc.1997.7082557.

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