Change detection in vegetation cover through interpretation of Landsat images by artificial neural networks (ANN). Case study: Ecuadorian Amazon Region

[EN] The interpretation of classes and change detection in the vegetation cover of large areas are activities that are made possible by the use of technologies and methods associated to Remote Sensing. Satellite images of medium and high spatial and spectral resolution are fundamental tools for the execution of projects with objectives of classification of vegetal cover and detection of its temporal variations. To exploit the use of digital information of territory recovered by the satellite images, and in order to optimize the resources invested in the tasks of classification and interpretation, it is necessary to have tools and methods that allow the automation of the processes involved and prove to be the Artificial Neural Networks (ANNs) an adequate mechanism for the execution of these processes. The main objective of this work is to validate a methodology for the identification of changes in the vegetation cover of an area located in the Ecuadorian Amazon. The applied methodology seeks the change detection in the coverage of native forests prevailing in the study region.[ES] La interpretación de clases y detección de cambios en la cobertura vegetal de áreas extensas, son actividades que se viabilizan mediante el uso de tecnologías y métodos asociados a la Percepción Remota. Imágenes satelitales de media y alta resolución espacial y espectral, constituyen herramientas fundamentales para la ejecución de proyectos que tienen como objetivo principal la clasificación de la cobertura vegetal y la detección de sus variaciones temporales. Para explotar de mejor forma el uso de la información del territorio recuperada por las imágenes satelitales, y con el fin de optimizar los recursos invertidos en las tareas de clasificación e interpretación, es requerimiento disponer de herramientas y métodos que permitan la automatización de los procesos involucrados. Las Redes Neuronales Artificiales (RNAs) demuestran ser un mecanismo adecuado para la ejecución de estos procesos. El presente trabajo, tiene como principal objetivo validar una metodología para la identificación de cambios en la cobertura vegetal de un área localizada en la Amazonía ecuatoriana. La metodología aplicada busca principalmente la detección de cambios en la cobertura de bosques nativos predominantes en la región de estudio.Jaramillo, L.; Antunes, A. (2018). Detección de cambios en la cobertura vegetal mediante interpretación de imágenes Landsat por redes neuronales artificiales (RNA). Caso de estudio: Región Amazónica Ecuatoriana. Revista de Teledetección. (51):33-46. doi:10.4995/raet.2018.8995SWORD334651Achard, F. 2002. Determination of Deforestation Rates of the World's Humid Tropical Forests. Science, 297(5583), 999-1002. https://doi.org/10.1126/ science.1070656Ambrosio, G., González, J., Arévalo, V. 2009. Comparación de imágenes de satélite para la Detección de Cambios Temporales. Málaga, España. Dpto. Ingeniería de Sistemas y Automática. Universidad de Málaga, p. 1-6. Último acceso: 7 julio 2014, de http://mapir.isa.uma.es/varevalo/ drafts/ambrosio2003cis.pdfAngelsen, A., Kaimowitz, D. 1999. Rethinking the causes of deforestation: lessons from economic models. The World Bank Research Observer, 14(1), 73-98. https://doi.org/10.1093/wbro/14.1.73Basogain, X. 2008. Redes neuronales artificiales y sus aplicaciones. Departamento de Ingeniería de Sistemas y Automática, Escuela Superior de Ingeniería Bilbao. Open Course Ware. País Vasco. Último acceso: 28 de ctubre 2014, de https://ocw.ehu. eus/pluginfile.php/9047/mod_resource/content/1/ redes_neuro/contenidos/pdf/libro-del-curso.pdfCenteno, J. A. S. 2003. Sensoriamento remoto e processamento de imagens digitais. Curitiba: UFPR.Chander, G., Markham, B. 2003. Revised Landsat-5 TM Radiometrie Calibration Procedures and Postcalibration Dynamic Ranges. IEEE Transactions on Geoscience and Remote Sensing, 41(11) Part II, 2674-2677. https://doi.org/10.1109/ TGRS.2003.818464Cohen, J. 1960. A Coefficient of Agreement for Nominal Scales. Educational and Psychological Measurement, 20(1), 37-46. https://doi. org/10.1177/001316446002000104Crosta, A. P. 1999. Processamento digital de imagens de sensoriamento remoto. Campinas: UNICAMP/ Instituto de Geociências.Haykin, S. 2001. Redes neurais: princípios e prática. Bookman, 900.Ílsever, M., Ünsalan, C. 2012. Pixel-Based Change Detection Methods. Two-Dimensional Change Detection Methods. Springer. 7-22. https://doi.org/10.1007/978-1-4471-4255-3_2Isasi, P., Galván, I. 2004. Redes de neuronas artificiales. Un enfoque práctico. Madrid: Prentice Hall.Kaufman, Y. J., Wald, A. E., Remer, L. A., Gao, B.- C., Li, R.-R., Flynn, L. 1997. The MODIS 2.1um channel-correlation with visible reflectance for use in remote sensing of aerosol. IEEE Transactions on Geoscience and Remote Sensing, 35(5), 1286-1298. https://doi.org/10.1109/36.628795Keenan, R. J., Reams, G. A., Achard, F., De Freitas, J. V., Grainger, A., Lindquist, E. 2015. Dynamics of global forest area: results from the FAO Global Forest Resources Assessment 2015. Forest Ecology and Management, 352, 9-20. https://doi.org/10.1016/j.foreco.2015.06.014Kotchenova, S. Y., Vermote, E. F., Matarrese, R., Frank J., Klemm, J. 2006. Validation of a vector version of the 6S radiative transfer code for atmospheric correction of satellite data. Part I: Path radiance. Applied Optics, 45(26), 6762-6774, set. Disponible en: Último acceso: 22 mayo 2015, de http://ao.osa.org/abstract.cfm?URI=ao-45-26-6762Lu, D., Mausel, P., Brondízio, E., Moran, E. 2004. Change detection techniques. International Journal of Remote Sensing, 25(12), 2365-2401. https://doi.org/10.1080/0143116031000139863MAE. (2012a). Metodología para la Representación Cartográfica de los Ecosistemas del Ecuador Continental. Ministerio del Ambiente del Ecuador. Último acceso: 29 de Agosto de 2014, de http://www.ambiente.gob.ec/wp-content/ uploads/downloads/2012/09/Documento_ Metodolog+¡a_28_05_2012_v2_1.pdfMAE (2012b). Línea Base de deforestación del Ecuador Continental. Ministerio del Ambiente de Ecuador. Último acceso en: 28 de octubre de 2014, de http:// sociobosque.ambiente.gob.ec/files/Folleto%20 mapa-parte1.pdfMoya, A. 2012. Detección automática de nuevas construcciones a partir de ortofotos. Universitat de Valencia. Último acceso: 28 de agosto de 2014, de http://personales.upv.es/almofue/ curso02/26092012Tesina.pdfOpenForis 2009. Open Foris Geospatial Tools. Food and Agriculture Organization of United Nations (FA0). Último acceso: 25 de febrero de 2017, de http://www.fao.org/forestry/fma/openforis/en/Schmidt, G., Jenkerson, C., Masek, J., Vermote, E., Gao, F. 2013. Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) Algorithm DescriptionOpen-file Report 2013-1057. U.S. Geologycal Survey Home Page. Último acceso: 16/ agosto/2017, de http://pubs.usgs.gov/of/2013/1057/Singh, A. 1989. Review Article Digital change detection techniques using remotely-sensed data. International Journal of Remote Sensing, 10(6), 989-1003. https:// doi.org/10.1080/01431168908903939SUIA 1990. Sistema Único de Información Ambiental - Ministerio del Ambiente del Ecuador. Mapa Interactivo Ambiental. Último acceso en: 30 de junio de 2015, de http://mapainteractivo.ambiente.gob.ec/USGS. Landsat Surface Reflectance Higher-Level Data Products. U.S. Geologycal Survey Home Page. Último acceso: 28 de mayo de 2015, de https://landsat.usgs.gov/landsat-surface-reflectancehigh-level-data-productsValencia, R., Cerón, C., Palacios, W., Sierra, R. (1999). Las formaciones naturales de la Amazonía del Ecuador. Sierra, R. (ed) Propuesta preliminar de un sistema de clasificación de vegetación para el Ecuador continental. Proyecto INEFAN/GEF-BIRF y EcoCiencia, Quito, 109-119.Vermote, E. F., Tanré, D., Deuzé, J. L., Herman, M., Morcrette, J. J. 1997. Second simulation of the satellite signal in the solar spectrum, 6s: an overview. IEEE Transactions on Geoscience and Remote Sensing, 35(3), 675-686. https://doi.org/10.1109/36.58198

Chirped polymer optical fiber Bragg grating sensors

We report chirped fiber Bragg gratings (CFBGs) photo-inscribed in undoped PMMA polymer optical fibre (POF) for the first time. The chirped polymer optical fiber Bragg gratings (CPOFBGs) were inscribed using an UV KrF excimer laser operating at 248 nm. The rectangular gauss laser beam was expanded to 25 mm in horizontal direction along the fiber core by a cylindrical lens, giving a total of 25 mm grating length. A 25 mm long chirped phase mask chosen for 1550 nm grating inscription was used. The laser frequency was 1 Hz with an energy of 5 mJ per exposure, exposing few pulses for each grating inscription. The reflection amplitude spectrum evolution of a CPOFBG is investigated as a function of the applied strain and temperature. Also, some results regarding to group delay are collected and discussed. These results pave the way to further developments in different fields, where POFs could present some advantages preferably replacing their silica counterparts

Estudo da Sensibilização aos Aeroalergenos Phl p 1, Phl p 5, Ole e 1 e Ole e 2 em Doentes com Patologia Alérgica Sazonal

Introdução: A sensibilização aos pólenes depende de vários factores nomeadamente do tipo de vegetação local e sabe-se que a sintomatologia não está apenas associada à exposição aos pólens mas também a partículas, algumas das quais resultantes da rotura dos grãos de pólen sendo posteriormente aerossolizadas. Objectivos: Relacionar a sensibilização de doentes com a concentração polínica atmosférica e a concentração de alguns dos respectivos aerolergenos. Métodos: Das consultas externas de Imunoalergologia dos hospitais de Évora e Elvas seleccionaram-se doentes que apresentavam queixas sazonais de rinite alérgica e asma brônquica, aos quais foram realizados testes cutâneos em Prick, standardizados, aos pólenes identificados na região. A 55 doentes foram realizados testes ao extracto de Phleum, aos seus alergénios Phl p 1 e Phl p 5, bem como aos extractos das restantes gramíneas e a 47 doentes foram realizados testes ao extracto de Olea, aos seus alergénios Ole e 1 e Ole e 2. Monitorizaram-se diariamente as partículas polínicas e os aeroalergenos mediante 2 colectores específicos para cada tipo. Resultados: A percentagem de doentes que é sensível aos 3 extractos de Phleum (Phleum total, Phl p 1 e Phl p 5) é de 51% , a dos que são sensíveis aos extractos de Phleum total e Phl p 1 é de 16 % e a dos que são sensíveis a Phleum total e Phl p5 é de 2%. A percentagem de doentes que é sensível a somente um dos extractos é de 20% e os que não têm qualquer sensibilidade são 11%. A percentagem de doentes que é sensível aos 3 extractos de Olea (Olea total, Ole e 1 e Ole e 2) é de 23%, a dos que são sensíveis à Olea total e Ole e 1 é de 21 % e a dos que são sensíveis à Olea total e Ole e 2 é de apenas 4%. A percentagem dos que são sensíveis a um dos extractos é de 19% e a dos que não apresentaram qualquer sensibilidade é de 32%. Conclusões: Podemos concluir que 89% dos doentes mostraram ser sensíveis aos alergénios da gramínea Phleum pratense pois mostraram positividade tanto ao extracto de Phleum e/ou aos seus alergénios Phl p 1 e Phl p 5. Em relação à oliveira, 44% dos doentes são alérgicos a este pólen pois são sensíveis ao seu alergénio major, Ole e 1. Em ambos os casos estão correlacionados com os aeroalergenos detectados nas amostras de ar, sendo a sensibilidade aos pólenes de gramíneas maior que a sensibilidade ao pólen de oliveira. Mais estudos devem ser realizados para despiste de reacções cruzadas nomeadamente quanto à Olea com outras plantas da região

Bragg gratings inscription using PMMA polymer optical fibers drawn from preforms with specific thermal pre-treatment

In this work, fiber Bragg gratings (FBGs) are inscribed in various undoped poly(methyl methacrylate) (PMMA) polymer optical fibres (POFs) using different types of UV lasers and inscription time and their temperature and strain sensitivities are investigated. The polymer optical fiber Bragg gratings (POFBGs) were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. The PMMA POFs drawn from a preform without specific thermal pre-treatment need more inscription time than the fibers drawn from a preform that has been pre-annealed at 80ºC for 2 weeks. Using both UV lasers, for the latter fiber less than half the inscription time is needed compared with a commercial undoped PMMA POF and other homemade POFs, where the preforms have not had a well-defined thermal pre-treatment. The effect on a POF from a preform that has been annealed prior to drawing is different as previously shown in the literature, where these POFs are much less sensitive to thermal treatment. Also, a proper polymerization process plays a key role as will be discussed. These results indicate the impact of preform thermal pre-treatment as well as polymerization process before the PMMA POFs drawing, which can be an essential characteristic in view of developing POF sensors technology

High-quality Phase-Shifted Bragg grating sensor inscribed with only one laser pulse in a polymer optical fiber

We present the first phase-shifted polymer optical fiber Bragg grating sensor inscribed with only one KrF laser pulse. The phase shift defect was created directly during the grating inscription process by placing a very narrow blocking aperture, in the center of the UV beam. One laser pulse with a duration of 15 ns and energy 6.3 mJ is adequate to introduce a refractive index change of 0.69×10-4 in the fiber core. The high-quality produced Bragg grating structure rejects 16.3 dB transmitted power, thus providing 97.6% reflectivity, which is well suited for photonic applications. The transmission notch depth is about 10 dB and very sharp notches of 3 dB width ranging from 14 pm is reported. The temperature, strain, and pressure response of the sensor has been characterized showing promising results in applications that require high-precision measurements. The ability to inscribe these high-quality sensors effectively can significantly reduce their production cost in industry

Phase-shifted Bragg grating inscription in PMMA microstructured POF using 248 nm UV radiation

In this work we experimentally validate and characterize the first phase-shifted polymer optical fiber Bragg gratings (PS-POFBGs) produced using a single pulse from a 248 nm krypton fluoride laser. A single-mode poly (methyl methacrylate) optical fiber with a core doped with benzyl dimethyl ketal for photosensitivity improvement was used. A uniform phase mask customized for 850 nm grating inscription was used to inscribe these Bragg structures. The phase shift defect was created directly during the grating inscription process by placing a narrow blocking aperture in the center of the UV beam. The produced high-quality Bragg grating structures, presenting a double dips, reject 16.3 dB (97.6% reflectivity) and 13.2 dB (95.2% reflectivity) of the transmitted power, being therefore appropriate for sensing or other photonic applications. Its transmission spectrum possesses two sharp transmission notches, allowing a significant increase in measurement resolution compared to direct interrogation of a single grating. The reflection and transmission spectra when multiple phase shifts are introduced in the FBG structure are also shown. The PS-POFBG's strain, temperature, pressure, and humidity characteristics have been experimentally analyzed in detail to assess their potential usage as sensors

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters