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The parabolic equation methods are advantageous in simulating under small time frames because of their low computational complexity. Because of this they are also feasible to implement on low end hardware. Due to the parabolic approximation they are based on, much work exists on improving the error introduced from the approximation. In this publication, further effort is put into developing these methods and the result from a master thesis at Tietoevry are presented. An in-house algorithm for evaporation duct propagation has been altered to improve the terrain modeling and to include range varying refractivity in a split step Fourier method called the discrete mixed Fourier transform. Previously only the piecewise linear shift map was utilized for terrain modeling which is known to become unstable at propagation angles exceeding around 15 degrees from the horizontal. By utilizing a hybrid method between piecewise linear shift map and knife edge method the stability issues are partially avoided, hence the solutions generated with the hybrid method are stable for a larger range of slope angles than with only using piecewise linear shift map. The range varying refractivity was included in the discrete mixed fourier transform by indexing making it possible to simulate dynamic evaporation duct heights. The report starts with a review of the theoretical foundation that the algorithm is built upon. Secondly, a logical list of steps outlines the altered algorithm. To conclude, the changes to the code are presented and discussed with the new results together with remarks on possible future improvements and current problems with the algorithm.

The parabolic equation methods are advantageous in simulating under small time frames because of their low computational complexity. Because of this they are also feasible to implement on low end hardware. Due to the parabolic approximation they are based on, much work exists on improving the error introduced from the approximation. In this publication, further effort is put into developing these methods and the result from a master thesis at Tietoevry are presented. An in-house algorithm for evaporation duct propagation has been altered to improve the terrain modeling and to include range varying refractivity in a split step Fourier method called the discrete mixed Fourier transform. Previously only the piecewise linear shift map was utilized for terrain modeling which is known to become unstable at propagation angles exceeding around 15 degrees from the horizontal. By utilizing a hybrid method between piecewise linear shift map and knife edge method the stability issues are partially avoided, hence the solutions generated with the hybrid method are stable for a larger range of slope angles than with only using piecewise linear shift map. The range varying refractivity was included in the discrete mixed fourier transform by indexing making it possible to simulate dynamic evaporation duct heights. The report starts with a review of the theoretical foundation that the algorithm is built upon. Secondly, a logical list of steps outlines the altered algorithm. To conclude, the changes to the code are presented and discussed with the new results together with remarks on possible future improvements and current problems with the algorithm.

Several optimization problems have features that hinder the capabilities of searching heuristics. To cope with this issue, different methods have been proposed to manipulate search spaces and improve the optimization process. This paper focuses on Dilation Functions (DFs), which are one of the most promising techniques to manipulate the fitness landscape, by expanding or compressing specific regions. The definition of appropriate DFs is problem dependent and requires a-priori knowledge of the optimization problem. Therefore, it is essential to introduce an automatic and efficient strategy to identify optimal DFs. With this aim, we propose a novel method based on Genetic Programming, named GP4DFs, which is capable of evolving effective DFs. GP4DFs identifies optimal dilations, where a specific DF is applied to each dimension of the search space. Moreover, thanks to a knowledge-driven initialization strategy, GP4DFs converges to better solutions with a reduced number of fitness evaluations, compared to the state-of-the-art approaches. The performance of GP4DFs is assessed on a set of 43 benchmark functions mimicking several features of real-world optimization problems. The obtained results indicate the suitability of the generated DFs.

© 2011 Optical Society of America. The financial support of the Spanish Ministry of Science and Innovation under project TEC2008-04105 is acknowledged. José A. Rodrigo gratefully thanks a “Juan de la Cierva” grant and A. Cámara acknowledges the financial support of the “Comunidad de Madrid” and the European Social Fund., In this work, we propose a robust and versatile approach for the characterization of the complex field amplitude of holographically generated coherent-scalar paraxial beams. For this purpose we apply an iterative algorithm that allows recovering the phase of the generated beam from the measurement of its Wigner distribution projections. Its performance is analyzed for beams of different symmetry: Laguerre-Gaussian, Hermite-Gaussian and spiral ones, which are obtained experimentally by a computer generated hologram (CGH) implemented on a programmable spatial light modulator (SLM). Using the same method we also study the quality of their holographic recording on a highly efficient photopolymerizable glass. The proposed approach is useful for the creation of adaptive CGH that takes into account the peculiarities of the SLM, as well as for the quality control of the holographic data storage., Ministerio de Ciencia e Innovación, España, Ministerio de Economía y Competitividad, España, Comunidad de Madrid, European Social Fund, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2006 Optical Society of America. We acknowledge Spain’s Ministerio de Ciencia y Tecnologia for providing economic support for this work under the auspices of project DP12002-02104., In many fringe pattern processing applications the local phase has to be obtained from a sinusoidal irradiance signal with unknown local frequency. This process is called asynchronous phase demodulation. Existing algorithms for asynchronous phase detection, or asynchronous algorithms, have been designed to yield no algebraic error in the recovered value of the phase for any signal frequency. However, each asynchronous algorithm has a characteristic frequency response curve. Existing asynchronous algorithms present a range of frequencies with low response, reaching zero for particular values of the signal frequency. For real noisy signals, low response implies a low signal-to-noise ratio in the recovered phase and therefore unreliable results. We present a new Fourier-based methodology for designing asynchronous algorithms with any user-defined frequency response curve and known limit of algebraic error. We show how asynchronous algorithms designed with this method can have better properties for real conditions of noise and signal frequency variation., Spain’s Ministerio de Ciencia y Tecnología, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2011 Optical Society of America. The project TEC2008-04105 from the Spanish Ministry of Science and Innovation is acknowledged. A. Cámara and J. A. Rodrigo thank the financial support from the Consejería de Educación de la Comunidad de Madrid together with the European Social Fund and Juan de la Cierva grant., We show the adaptation of a multifunctional optical system consisting of two spatial light modulators for the optimal measurement of the Radon-Wigner transform of one-dimensional signals. The proposed Radon-Wigner display allows reconstructing the Wigner distribution and the phase or the mutual intensity of fully or partially coherent fields, respectively. It is also suitable for the analysis of two-dimensional rotationally symmetric or separable in Cartesian coordinates optical fields. The feasibility of the proposed scheme is experimentally demonstrated in several examples., Ministerio de Ciencia e Innovación (MICINN), España, Consejería de Educación de la Comunidad de Madrid, European Social Fund, Subprograma Juan de la Cierva, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

The authors wish to acknowledge Dr. L. Jañez Head of the Instituto Complutense de Imagen y Telemedicina, E. Ortiz co-worker in the same Institution, and Dr. Carreras Head of PET Institute, for his support in the medical image fusion applications. They have provided us with the medical images shown in this work. The constructive recommendations provided by the reviewers are also gratefully acknowledged., The objective of image fusion is to combine information from multiple images of the same scene. The result of image fusion is a new image which is more suitable for human and machine perception or further image-processing tasks such as segmentation, feature extraction and object recognition. Different fusion methods have been proposed in literature, including multiresolution analysis. This paper is an image fusion tutorial based on wavelet decomposition, i.e. a multiresolution image fusion approach. We can fuse images with the same or different resolution level, i.e. range sensing, visual CCD, infrared, thermal or medical. The tutorial performs a synthesis between the multi scale-decomposition-based image approach (Proc. IEEE 87 (8) (1999) 1315), the ARSIS concept (Photogramm. Eng. Remote Sensing 66 (1) (2000) 49) and a multisensor scheme (Graphical Models Image Process. 57 (3) (1995) 235). Some image fusion examples illustrate the proposed fusion approach. A comparative analysis is carried out against classical existing strategies, including those of multiresolution., Sección Deptal. de Arquitectura de Computadores y Automática (Físicas), Fac. de Ciencias Físicas, TRUE, pub

© 2008 Optical Society of America. We acknowledge the financial support of this work by the Ministerio de Educacion y Ciencia, project DP12005-03891., We present a spatial adaptive asynchronous algorithm for fringe pattern demodulation. The proposed algorithm is based on the standard five-step asynchronous method with the one modification that we select the best sample spacing for each point of the fringe pattern. As we show, the frequency response of any asynchronous method depends on the sample spacing. This interesting behavior is used to select the best sample spacing as the one that gives the biggest response for each location. The overall result is a spatial demodulation algorithm with an improved frequency response compared to the existing ones. We show the feasibility of the proposed method with theoretical analysis as well as experimental results., Ministerio de Educación y Ciencia, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© The 2011 Optical Society of America. This work was partially supported by the Spanish Ministry of Science and Technology under grant DPI2009-09023., In phase sampling interferometry, existing temporal analysis methods are sensitive to border effects and cannot deal with missing data. In this work we propose a quadrature filter that allows a reliable dynamic phase measurement for every sample, even in the cases involving few samples or missing data. The method is based on the use of a regularized least squares cost function that enforces the quadrature character of the filter. A comparison with existing techniques shows the effectiveness of the proposed method., Spanish Ministry of Science and Technology, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2015 SPIE. Spanish Ministerio de Economía y Competitividad is acknowledged for funding the project TEC2011-23629., Partially coherent light provides attractive benefits for different applications in microscopy, astronomy, telecommunications, optical lithography, etc. However, design and generation of partially coherent beams with desirable properties is challenging. Moreover, the experimental characterization of the spatial coherence is a difficult problem involving second-order statistics represented by four-dimensional functions that cannot be directly measured and analyzed. We discuss the techniques for design and generation of partially coherent structurally stable beams and the recently developed phase-space tomography methods supported by simple experimental setups for practical quantitative characterization of partially coherent light spatial structure, including its local coherence properties., Ministerio de Economía y Competitividad (MINECO), España, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2002 IOP Publishing Ltd. Financial assistance fromthemultidisciplinary project PR486/97-7477/97from Complutense University of Madrid and grant TIC2000-2791-E from the Spanish Ministry of Science and Technology is acknowledged. TA would like to acknowledge the financial support from Secretaría de Estado de Educación y Universidades (SB2000-0166), the Spanish Ministry of Education, Culture and Sport., The main properties of the power filtering operation in the fractional Fourier domain and its relationship to the differentiation operation are considered. The application of linear power filtering for solving the phase retrieval problem from intensity distributions only is proposed. The optical configuration for the experimental realization of the method is discussed., Universidad Complutense de Madrid (UCM), Ministerio de Ciencia y Tecnología, España, Secretaría de Estado de Educación y Universidades, Ministerio de Educación, Cultura y Deporte, España, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2003 Optical Society of America. Financial assistance from the Spanish Ministry of Science and Technology (project TIC 2002-01846) is acknowledged. T. Alieva acknowledges the financial support of Secretaría de Estado de Educación y Universidades de España (SB2000-0166) (Spanish Ministry of Education, Culture, and Sports)., The importance of the amplitude and phase in the fractional Fourier transform (FT) domain is analyzed on the basis of the rectangular signal and the real-world image. The quality of signal restoration from only the amplitude or from only the phase of its fractional FT by applying the inverse fractional FT is considered. It is shown that the signal reconstructed from the amplitude of the fractional FT usually reveals the main features of the original signal only for relatively low fractional orders. On the basis of phase information in the fractional FT domains, significant details of the signal can be obtained for nearly all fractional orders., Ministerio de Ciencia y Tecnología, España, Secretaría de Estado de Educación y Universidades de España, Ministerio de Educación, Cultura y Deporte (MECD), España, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2009 Optical Society of America. The financial support of the Spanish Ministry of Science and Innovation under project TEC 2008-04105/TEC is acknowledged. T. Alieva appreciates the financial support of the Banco Santander Central Hispano and Universidad Complutense de Madrid under project Santander-Complutense, PR-34/07-15914. J. A. Rodrigo acknowledges the Spanish Ministry of Science and Innovation for the “Juan de la Cierva” grant. We also thank G. Cristóbal for his valuable discussions on the numerical calculation of the WD., We propose a simple approach for the phase space tomography reconstruction of the Wigner distribution of paraxial optical beams separable in Cartesian coordinates. It is based on the measurements of the antisymmetric fractional Fourier transform power spectra, which can be taken using a flexible optical setup consisting of four cylindrical lenses. The numerical simulations and the experimental results clearly demonstrate the feasibility of the proposed scheme., Ministerio de Ciencia e Innovación (MICINN), España, Banco Santander Central Hispano (BSCH), Universidad Complutense de Madrid (UCM), Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

© 2006 Optical Society of America. T. Alieva thanks the Spanish Ministry of Education and Science for financial support (TEC2005-02180/MIC). M. J. Bastiaans can be reached at m.j.bastiaans@tue.nl, and T. Alieva at talieva@fis.ucm.es., On the basis of the modified Iwasawa decomposition of a lossless first-order optical system as a cascade of a lens, a magnifier, and a so-called orthosymplectic system, we show how to synthesize an arbitrary ABCD system (with two transverse coordinates) by means of lenses and predetermined sections of free space such that the lenses are located at fixed positions., Spanish Ministry of Education and Science, Depto. de Óptica, Fac. de Ciencias Físicas, TRUE, pub

The objetive of these notes is to give a brief overview of wavelet theory, both of the fundamental mathematical arguments and of the ideas it contains. In addition, the theory is suitable for multidisciplinary work., El objetivo de estas notas es dar un breve panorama de la teoría de ondículas, tanto de los argumentos matemáticos fundamentales como de las ideas que ella encierra. Además, la teoría sirve para un trabajo multidisciplinario.

The January 2022 Hunga Tonga-Hunga Ha'apai eruption was one of the most explosive volcanic events of the modern era(1,2), producing a vertical plume that peaked more than 50 km above the Earth(3). The initial explosion and subsequent plume triggered atmospheric waves that propagated around the world multiple times(4). A global-scale wave response of this magnitude from a single source has not previously been observed. Here we show the details of this response, using a comprehensive set of satellite and ground-based observations to quantify it from surface to ionosphere. A broad spectrum of waves was triggered by the initial explosion, including Lamb waves(5,6) propagating at phase speeds of 318.2 +/- 6 m s(-1) at surface level and between 308 +/- 5 to 319 +/- 4 m s(-1) in the stratosphere, and gravity waves(7) propagating at 238 +/- 3 to 269 +/- 3 m s(-1) in the stratosphere. Gravity waves at sub-ionospheric heights have not previously been observed propagating at this speed or over the whole Earth from a single source(8,9). Latent heat release from the plume remained the most significant individual gravity wave source worldwide for more than 12 h, producing circular wavefronts visible across the Pacific basin in satellite observations. A single source dominating such a large region is also unique in the observational record. The Hunga Tonga eruption represents a key natural experiment in how the atmosphere responds to a sudden point-source-driven state change, which will be of use for improving weather and climate models.

We propose an asymmetric cryptosystem based on optical scanning cryptography (OSC) and elliptic curve cryptography (ECC) algorithm. In the encryption stage of OSC, an object is encrypted to cosine and sine holograms by two pupil functions calculated via ECC algorithm from sender's biometric image, which is sender's private key. With the ECC algorithm, these holograms are encrypted to ciphertext, which is sent to the receiver. In the stage of decryption, the encrypted holograms can be decrypted by receiver's biometric private key which is different from the sender's private key. The approach is an asymmetric cryptosystem which solves the problem of the management and dispatch of keys in OSC and has more security strength than the conventional OSC. The feasibility of the proposed method has been convincingly verified by numerical and experiment results.

Low-frequency artifacts in reverse time migration result from unwanted cross-correlation of the source and receiver wavefields at nonreflecting points along ray-paths. These artifacts can hide important details in migrated models and increase poor interpretation risk. Some methods have been proposed to avoid or reduce the number of these artifacts, preserving reflections, and improving model quality, implementing other strategies such as modification of the wave equation, proposing other imaging conditions, and using image filtering techniques. One of these methods uses wavefield decomposition, correlating components of the wavefields that propagate in opposite directions. We propose a method for extracting directional information from the RTM imaging condition wavefields to obtain characteristics allowing for better, more refined imaging. The method works by separating directional information about the wavefields based on the continuous wavelet transform (CWT), and the analysis of the main changes on the frequency content revealed within the scalogram obtained by a Gaussian wavelet family. Through numerical applications, we demonstrate that this method can effectively remove undesired artifacts in migrated images. In addition, we use the Laguerre-Gauss filtering to improve the results obtained with the proposed method. © 2018 Ecopetrol S.A. All Rights Reserved.

In this paper, the representation of the situation behind the hypothalamic device by means of language units can be given in several transformational patterns. In this process, a specific paradigm of the hypothalamic device is formed and the members of the paradigm differ according to their syntactic forms and the morphological means used in them.

In this paper, the representation of the situation behind the hypothalamic device by means of language units can be given in several transformational patterns. In this process, a specific paradigm of the hypothalamic device is formed and the members of the paradigm differ according to their syntactic forms and the morphological means used in them.

In this paper, the representation of the situation behind the hypothalamic device by means of language units can be given in several transformational patterns. In this process, a specific paradigm of the hypothalamic device is formed and the members of the paradigm differ according to their syntactic forms and the morphological means used in them.

In this paper, the representation of the situation behind the hypothalamic device by means of language units can be given in several transformational patterns. In this process, a specific paradigm of the hypothalamic device is formed and the members of the paradigm differ according to their syntactic forms and the morphological means used in them.

In this paper, the representation of the situation behind the hypothalamic device by means of language units can be given in several transformational patterns. In this process, a specific paradigm of the hypothalamic device is formed and the members of the paradigm differ according to their syntactic forms and the morphological means used in them.

In this paper, the representation of the situation behind the hypothalamic device by means of language units can be given in several transformational patterns. In this process, a specific paradigm of the hypothalamic device is formed and the members of the paradigm differ according to their syntactic forms and the morphological means used in them.

In this paper, the representation of the situation behind the hypothalamic device by means of language units can be given in several transformational patterns. In this process, a specific paradigm of the hypothalamic device is formed and the members of the paradigm differ according to their syntactic forms and the morphological means used in them.

Today’s world has a markedly Dynamic character which demands the Mexican educational system as a whole, but specifically the schools where the new teachers are formed, as well as the classroom teaching practices, to be transformed to face that reality. We recognize the only unfailing agent that is able to generate that change is the teacher who embraces a critical pedagogy and who also knows the science, pedagogy and philosophy to exert a reflective practice. A critical and transforming teacher is formed in teacher education schools, developing and improving what a teacher who takes that role must have. These qualities are not attained by means of simple experience, what is truly necessary is that he or she obtains philosophic referents that allows him or her, first, to reflect on the impact of good teaching practices, then, become an agent of change. Additionally, he or she must contribute to the construction of an emerging philosophy that would help him or her solve real problems, such as the one that COVID-19 generated, where we witnessed that the educational authorities left aside this philosophic reflection by sustaining rigid, unwavering, and traditional conceptions of the curriculum, El mundo actual tiene un carácter marcadamente dinámico, por lo que el Sistema Educativo Mexicano (SEM) en su conjunto, pero particularmente las escuelas formadoras de docentes y las prácticas de enseñanza en el aula, deben transformarse para hacer frente a esa realidad. Se reconoce que el único agente indefectible que puede generar ese cambio es el docente que abrace una pedagogía crítica y que sea conocedor de la ciencia, la pedagogía y la filosofía para que ejerza una práctica reflexiva. El presente trabajo presenta una revisión teórico conceptual de la necesidad de docentes críticos transformadores en la realidad mexicana, empleando referentes como Freire y analizando también algunos elementos de la Nueva Escuela Mexicana (NEM). Un docente crítico y transformador se forja en las escuelas normales, desarrollando y potenciando lo que un profesor que asuma ese rol debe tener. Esas cualidades no se logran desde la simple experiencia, es necesario que se allegue de referentes de orden filosófico que le permitan, primero, reflexionar sobre el impacto de buenas prácticas de enseñanza, luego, tomar acción como agente de cambio. Además, debe abonar a la construcción de una filosofía emergente que le ayude a resolver problemas reales, como el generado por la COVID-19, donde se observó que la autoridad educativa dejó de lado esta reflexión filosófica y partió de concepciones rígidas, cerradas y tradicionalistas de currículo.

Today’s world has a markedly Dynamic character which demands the Mexican educational system as a whole, but specifically the schools where the new teachers are formed, as well as the classroom teaching practices, to be transformed to face that reality. We recognize the only unfailing agent that is able to generate that change is the teacher who embraces a critical pedagogy and who also knows the science, pedagogy and philosophy to exert a reflective practice. A critical and transforming teacher is formed in teacher education schools, developing and improving what a teacher who takes that role must have. These qualities are not attained by means of simple experience, what is truly necessary is that he or she obtains philosophic referents that allows him or her, first, to reflect on the impact of good teaching practices, then, become an agent of change. Additionally, he or she must contribute to the construction of an emerging philosophy that would help him or her solve real problems, such as the one that COVID-19 generated, where we witnessed that the educational authorities left aside this philosophic reflection by sustaining rigid, unwavering, and traditional conceptions of the curriculum, El mundo actual tiene un carácter marcadamente dinámico, por lo que el Sistema Educativo Mexicano (SEM) en su conjunto, pero particularmente las escuelas formadoras de docentes y las prácticas de enseñanza en el aula, deben transformarse para hacer frente a esa realidad. Se reconoce que el único agente indefectible que puede generar ese cambio es el docente que abrace una pedagogía crítica y que sea conocedor de la ciencia, la pedagogía y la filosofía para que ejerza una práctica reflexiva. El presente trabajo presenta una revisión teórico conceptual de la necesidad de docentes críticos transformadores en la realidad mexicana, empleando referentes como Freire y analizando también algunos elementos de la Nueva Escuela Mexicana (NEM). Un docente crítico y transformador se forja en las escuelas normales, desarrollando y potenciando lo que un profesor que asuma ese rol debe tener. Esas cualidades no se logran desde la simple experiencia, es necesario que se allegue de referentes de orden filosófico que le permitan, primero, reflexionar sobre el impacto de buenas prácticas de enseñanza, luego, tomar acción como agente de cambio. Además, debe abonar a la construcción de una filosofía emergente que le ayude a resolver problemas reales, como el generado por la COVID-19, donde se observó que la autoridad educativa dejó de lado esta reflexión filosófica y partió de concepciones rígidas, cerradas y tradicionalistas de currículo.

In this paper, the representation of the situation behind the hypothalamic device by means of language units can be given in several transformational patterns. In this process, a specific paradigm of the hypothalamic device is formed and the members of the paradigm differ according to their syntactic forms and the morphological means used in them.

Today’s world has a markedly Dynamic character which demands the Mexican educational system as a whole, but specifically the schools where the new teachers are formed, as well as the classroom teaching practices, to be transformed to face that reality. We recognize the only unfailing agent that is able to generate that change is the teacher who embraces a critical pedagogy and who also knows the science, pedagogy and philosophy to exert a reflective practice. A critical and transforming teacher is formed in teacher education schools, developing and improving what a teacher who takes that role must have. These qualities are not attained by means of simple experience, what is truly necessary is that he or she obtains philosophic referents that allows him or her, first, to reflect on the impact of good teaching practices, then, become an agent of change. Additionally, he or she must contribute to the construction of an emerging philosophy that would help him or her solve real problems, such as the one that COVID-19 generated, where we witnessed that the educational authorities left aside this philosophic reflection by sustaining rigid, unwavering, and traditional conceptions of the curriculum, El mundo actual tiene un carácter marcadamente dinámico, por lo que el Sistema Educativo Mexicano (SEM) en su conjunto, pero particularmente las escuelas formadoras de docentes y las prácticas de enseñanza en el aula, deben transformarse para hacer frente a esa realidad. Se reconoce que el único agente indefectible que puede generar ese cambio es el docente que abrace una pedagogía crítica y que sea conocedor de la ciencia, la pedagogía y la filosofía para que ejerza una práctica reflexiva. El presente trabajo presenta una revisión teórico conceptual de la necesidad de docentes críticos transformadores en la realidad mexicana, empleando referentes como Freire y analizando también algunos elementos de la Nueva Escuela Mexicana (NEM). Un docente crítico y transformador se forja en las escuelas normales, desarrollando y potenciando lo que un profesor que asuma ese rol debe tener. Esas cualidades no se logran desde la simple experiencia, es necesario que se allegue de referentes de orden filosófico que le permitan, primero, reflexionar sobre el impacto de buenas prácticas de enseñanza, luego, tomar acción como agente de cambio. Además, debe abonar a la construcción de una filosofía emergente que le ayude a resolver problemas reales, como el generado por la COVID-19, donde se observó que la autoridad educativa dejó de lado esta reflexión filosófica y partió de concepciones rígidas, cerradas y tradicionalistas de currículo.

In today's society, an enormous amount of data is created that is stored in various databases. Since the data is in many cases stored in different databases, there is a demand from organizations with a lot of data to be able to merge separated data and get an extraction of this resource. Extract, Transform and Load System (ETL) is a solution that has made it possible to easily merge different databases. However, the ETL market has been owned by large actors such as Amazon and Microsoft and the solutions offered are completely owned by these actors. This leaves the consumer with little ownership of the solution. Therefore, this thesis proposes a framework to create a component based ETL which gives consumers an opportunity to own and develop their own ETL solution that they can customize to their own needs. The result of the thesis is a prototype ETL solution that is built with the idea of being able to configure and customize the prototype and it accomplishes this by being independent of inflexible external libraries and a level of modularity that makes adding and removing components easy. The results of this thesis are verified with a test that shows how two different files containing data can be combined., I dagens samhälle skapas det en enorm mängd data som är lagrad i olika databaser. Eftersom data i många fall är lagrat i olika databaser, finns det en efterfrågan från organisationer med mycket data att kunna slå ihop separerad data och få en utvinning av denna resurs. Extract, Transform and Load System (ETL) är en lösning som gjort det möjligt att slå ihop olika databaser. Dock är problemet denna expansion av ETL teknologi. ETL marknaden blivit ägd av stora aktörer såsom Amazon och Microsoft och de lösningar som erbjuds är helt ägda av dem. Detta lämnar konsumenten med lite ägodel av lösningen. Därför föreslår detta examensarbete ett ramverk för att skapa ett komponentbaserat ETL verktyg som ger konsumenter en möjlighet att utveckla en egen ETL lösning som de kan skräddarsy efter deras egna förfogande. Resultatet av examensarbete är en prototyp ETL-lösning som är byggd för att kunna konfigurera och skräddarsy prototypen. Lösningen lyckas med detta genom att vara oberoende av oflexibla externa bibliotek och en nivå av modularitet som gör addering och borttagning av komponenter enkelt. Resultatet av detta examensarbete är verifierat av ett test som visar på hur två olika filer med innehållande data kan kombineras.

Today’s world has a markedly Dynamic character which demands the Mexican educational system as a whole, but specifically the schools where the new teachers are formed, as well as the classroom teaching practices, to be transformed to face that reality. We recognize the only unfailing agent that is able to generate that change is the teacher who embraces a critical pedagogy and who also knows the science, pedagogy and philosophy to exert a reflective practice. A critical and transforming teacher is formed in teacher education schools, developing and improving what a teacher who takes that role must have. These qualities are not attained by means of simple experience, what is truly necessary is that he or she obtains philosophic referents that allows him or her, first, to reflect on the impact of good teaching practices, then, become an agent of change. Additionally, he or she must contribute to the construction of an emerging philosophy that would help him or her solve real problems, such as the one that COVID-19 generated, where we witnessed that the educational authorities left aside this philosophic reflection by sustaining rigid, unwavering, and traditional conceptions of the curriculum, El mundo actual tiene un carácter marcadamente dinámico, por lo que el Sistema Educativo Mexicano (SEM) en su conjunto, pero particularmente las escuelas formadoras de docentes y las prácticas de enseñanza en el aula, deben transformarse para hacer frente a esa realidad. Se reconoce que el único agente indefectible que puede generar ese cambio es el docente que abrace una pedagogía crítica y que sea conocedor de la ciencia, la pedagogía y la filosofía para que ejerza una práctica reflexiva. El presente trabajo presenta una revisión teórico conceptual de la necesidad de docentes críticos transformadores en la realidad mexicana, empleando referentes como Freire y analizando también algunos elementos de la Nueva Escuela Mexicana (NEM). Un docente crítico y transformador se forja en las escuelas normales, desarrollando y potenciando lo que un profesor que asuma ese rol debe tener. Esas cualidades no se logran desde la simple experiencia, es necesario que se allegue de referentes de orden filosófico que le permitan, primero, reflexionar sobre el impacto de buenas prácticas de enseñanza, luego, tomar acción como agente de cambio. Además, debe abonar a la construcción de una filosofía emergente que le ayude a resolver problemas reales, como el generado por la COVID-19, donde se observó que la autoridad educativa dejó de lado esta reflexión filosófica y partió de concepciones rígidas, cerradas y tradicionalistas de currículo.

Low-frequency artifacts in reverse time migration result from unwanted cross-correlation of the source and receiver wavefields at nonreflecting points along ray-paths. These artifacts can hide important details in migrated models and increase poor interpretation risk. Some methods have been proposed to avoid or reduce the number of these artifacts, preserving reflections, and improving model quality, implementing other strategies such as modification of the wave equation, proposing other imaging conditions, and using image filtering techniques. One of these methods uses wavefield decomposition, correlating components of the wavefields that propagate in opposite directions. We propose a method for extracting directional information from the RTM imaging condition wavefields to obtain characteristics allowing for better, more refined imaging. The method works by separating directional information about the wavefields based on the continuous wavelet transform (CWT), and the analysis of the main changes on the frequency content revealed within the scalogram obtained by a Gaussian wavelet family. Through numerical applications, we demonstrate that this method can effectively remove undesired artifacts in migrated images. In addition, we use the Laguerre-Gauss filtering to improve the results obtained with the proposed method. © 2018 Ecopetrol S.A. All Rights Reserved.

Reverse time migration (RTM) solves the acoustic or elastic wave equation by means of the extrapolation from source and receiver wavefield in time. A migrated image is obtained by applying a criteria known as imaging condition. The cross-correlation between source and receiver wavefields is the commonly used imaging condition. However, this imaging condition produces spatial low-frequency noise, called artifacts, due to the unwanted correlation of the diving, head and backscattered waves. Several techniques have been proposed to reduce the artifacts occurrence. Derivative operators as Laplacian are the most frequently used. In this work, we propose a technique based on a spiral phase filter ranging from 0 to 2p, and a toroidal amplitude bandpass filter, known as Laguerre-Gauss transform. Through numerical experiments we present the application of this particular filter on three synthetic data sets. In addition, we present a comparative spectral study of images obtained by the zero-lag cross-correlation imaging condition, the Laplacian filtering and the Laguerre-Gauss filtering, showing their frequency features. We also present evidences not only with simulated noisy velocity fields but also by comparison with the model velocity field gradients that this method improves the RTM images by reducing the artifacts and notably enhance the reflective events. © 2017 Sociedade Brasileira de Geofísica.

Today’s world has a markedly Dynamic character which demands the Mexican educational system as a whole, but specifically the schools where the new teachers are formed, as well as the classroom teaching practices, to be transformed to face that reality. We recognize the only unfailing agent that is able to generate that change is the teacher who embraces a critical pedagogy and who also knows the science, pedagogy and philosophy to exert a reflective practice. A critical and transforming teacher is formed in teacher education schools, developing and improving what a teacher who takes that role must have. These qualities are not attained by means of simple experience, what is truly necessary is that he or she obtains philosophic referents that allows him or her, first, to reflect on the impact of good teaching practices, then, become an agent of change. Additionally, he or she must contribute to the construction of an emerging philosophy that would help him or her solve real problems, such as the one that COVID-19 generated, where we witnessed that the educational authorities left aside this philosophic reflection by sustaining rigid, unwavering, and traditional conceptions of the curriculum, El mundo actual tiene un carácter marcadamente dinámico, por lo que el Sistema Educativo Mexicano (SEM) en su conjunto, pero particularmente las escuelas formadoras de docentes y las prácticas de enseñanza en el aula, deben transformarse para hacer frente a esa realidad. Se reconoce que el único agente indefectible que puede generar ese cambio es el docente que abrace una pedagogía crítica y que sea conocedor de la ciencia, la pedagogía y la filosofía para que ejerza una práctica reflexiva. El presente trabajo presenta una revisión teórico conceptual de la necesidad de docentes críticos transformadores en la realidad mexicana, empleando referentes como Freire y analizando también algunos elementos de la Nueva Escuela Mexicana (NEM). Un docente crítico y transformador se forja en las escuelas normales, desarrollando y potenciando lo que un profesor que asuma ese rol debe tener. Esas cualidades no se logran desde la simple experiencia, es necesario que se allegue de referentes de orden filosófico que le permitan, primero, reflexionar sobre el impacto de buenas prácticas de enseñanza, luego, tomar acción como agente de cambio. Además, debe abonar a la construcción de una filosofía emergente que le ayude a resolver problemas reales, como el generado por la COVID-19, donde se observó que la autoridad educativa dejó de lado esta reflexión filosófica y partió de concepciones rígidas, cerradas y tradicionalistas de currículo.

In today's society, an enormous amount of data is created that is stored in various databases. Since the data is in many cases stored in different databases, there is a demand from organizations with a lot of data to be able to merge separated data and get an extraction of this resource. Extract, Transform and Load System (ETL) is a solution that has made it possible to easily merge different databases. However, the ETL market has been owned by large actors such as Amazon and Microsoft and the solutions offered are completely owned by these actors. This leaves the consumer with little ownership of the solution. Therefore, this thesis proposes a framework to create a component based ETL which gives consumers an opportunity to own and develop their own ETL solution that they can customize to their own needs. The result of the thesis is a prototype ETL solution that is built with the idea of being able to configure and customize the prototype and it accomplishes this by being independent of inflexible external libraries and a level of modularity that makes adding and removing components easy. The results of this thesis are verified with a test that shows how two different files containing data can be combined., I dagens samhälle skapas det en enorm mängd data som är lagrad i olika databaser. Eftersom data i många fall är lagrat i olika databaser, finns det en efterfrågan från organisationer med mycket data att kunna slå ihop separerad data och få en utvinning av denna resurs. Extract, Transform and Load System (ETL) är en lösning som gjort det möjligt att slå ihop olika databaser. Dock är problemet denna expansion av ETL teknologi. ETL marknaden blivit ägd av stora aktörer såsom Amazon och Microsoft och de lösningar som erbjuds är helt ägda av dem. Detta lämnar konsumenten med lite ägodel av lösningen. Därför föreslår detta examensarbete ett ramverk för att skapa ett komponentbaserat ETL verktyg som ger konsumenter en möjlighet att utveckla en egen ETL lösning som de kan skräddarsy efter deras egna förfogande. Resultatet av examensarbete är en prototyp ETL-lösning som är byggd för att kunna konfigurera och skräddarsy prototypen. Lösningen lyckas med detta genom att vara oberoende av oflexibla externa bibliotek och en nivå av modularitet som gör addering och borttagning av komponenter enkelt. Resultatet av detta examensarbete är verifierat av ett test som visar på hur två olika filer med innehållande data kan kombineras.

Today’s world has a markedly Dynamic character which demands the Mexican educational system as a whole, but specifically the schools where the new teachers are formed, as well as the classroom teaching practices, to be transformed to face that reality. We recognize the only unfailing agent that is able to generate that change is the teacher who embraces a critical pedagogy and who also knows the science, pedagogy and philosophy to exert a reflective practice. A critical and transforming teacher is formed in teacher education schools, developing and improving what a teacher who takes that role must have. These qualities are not attained by means of simple experience, what is truly necessary is that he or she obtains philosophic referents that allows him or her, first, to reflect on the impact of good teaching practices, then, become an agent of change. Additionally, he or she must contribute to the construction of an emerging philosophy that would help him or her solve real problems, such as the one that COVID-19 generated, where we witnessed that the educational authorities left aside this philosophic reflection by sustaining rigid, unwavering, and traditional conceptions of the curriculum, El mundo actual tiene un carácter marcadamente dinámico, por lo que el Sistema Educativo Mexicano (SEM) en su conjunto, pero particularmente las escuelas formadoras de docentes y las prácticas de enseñanza en el aula, deben transformarse para hacer frente a esa realidad. Se reconoce que el único agente indefectible que puede generar ese cambio es el docente que abrace una pedagogía crítica y que sea conocedor de la ciencia, la pedagogía y la filosofía para que ejerza una práctica reflexiva. El presente trabajo presenta una revisión teórico conceptual de la necesidad de docentes críticos transformadores en la realidad mexicana, empleando referentes como Freire y analizando también algunos elementos de la Nueva Escuela Mexicana (NEM). Un docente crítico y transformador se forja en las escuelas normales, desarrollando y potenciando lo que un profesor que asuma ese rol debe tener. Esas cualidades no se logran desde la simple experiencia, es necesario que se allegue de referentes de orden filosófico que le permitan, primero, reflexionar sobre el impacto de buenas prácticas de enseñanza, luego, tomar acción como agente de cambio. Además, debe abonar a la construcción de una filosofía emergente que le ayude a resolver problemas reales, como el generado por la COVID-19, donde se observó que la autoridad educativa dejó de lado esta reflexión filosófica y partió de concepciones rígidas, cerradas y tradicionalistas de currículo.

Surfing in rough waters is not always as fun as wave riding the “big one”. Similarly, in optimization problems, fitness landscapes with a huge number of local optima make the search for the global optimum a hard and generally annoying game. Computational Intelligence optimization metaheuristics use a set of individuals that “surf” across the fitness landscape, sharing and exploiting pieces of information about local fitness values in a joint effort to find out the global optimum. In this context, we designed surF, a novel surrogate modeling technique that leverages the discrete Fourier transform to generate a smoother, and possibly easier to explore, fitness landscape. The rationale behind this idea is that filtering out the high frequencies of the fitness function and keeping only its partial information (i.e., the low frequencies) can actually be beneficial in the optimization process. We prove our theory by combining surF with a settings free variant of Particle Swarm Optimization (PSO) based on Fuzzy Logic, called Fuzzy Self-Tuning PSO. Specifically, we introduce a new algorithm, named F3ST-PSO, which performs a preliminary exploration on the surrogate model followed by a second optimization using the actual fitness function. We show that F3ST-PSO can lead to improved performances, notably using the same budget of fitness evaluations.

Traffic accidents are extremely rare, creating the need for surrogate methods for safety analysis that makes efficient use of the information provided by traffic conflicts, which also are limited in availability. The severity measure time-to-collision (TTC) in combination with extreme value theory have so far been one of the primary measures used to infer traffic safety levels, but it relies on unrealistic assumptions that results in severity measures that do not always agree well with observed danger. Stochastic TTC has been proposed as an alternative, which replaces the constant velocity trajectories used to define collision course with naturalistic ones, resulting in a distribution of potential TTC values. The main focus of this thesis is to find a way to mathematically model such data. Stochastic TTC is conceptualized within the framework of mixed distributions, and equations allowing for extreme value theory to be used in such a context are derived. A second point of focus is on presenting a new method for estimating the collision probability, allowing for separate estimation of collisions that occurred with and without attempts at evasive action. Also, the effects of data-transforms were investigated in a simulation setting, which proved highly useful in reducing the tendency for underestimation which seems to be a common problem when extreme value theory is applied to traffic data, and overall improving accuracy. Stochastic TTC and the proposed methods were also tested in this simulated traffic environment, which showed that stochastic TTC can work at least as well as regular TTC, but in order for more significant differences to be seen, the simulation would have to contain more variable road user behavior and more curved trajectories.

Nonlinear characteristics in the dynamic behaviors of civil structures degrade the performance of damage detection of the linear theory based traditional time- and frequency-domain methods. To overcome this challenge, this paper proposes a damage detection approach for nonlinear structures based on Variational Mode Decomposition (VMD). In this approach, the measured dynamic responses from nonlinear structures under earthquake excitations are adaptively decomposed into a finite number of monocomponents by using VMD. Each decomposed mono-component represents an amplitude modulated and frequency modulated (AMFM) signal with a limited frequency bandwidth. Hilbert transform is then employed to identify the instantaneous modal parameters of the decomposed monomodes, including instantaneous frequencies and mode shapes. Based on the identified modal parameters from the decomposed structural dynamic responses, two damage indices are defined to identify the location and severity of structural damage, respectively. To validate the effectiveness and accuracy of the proposed approach, a nonlinear seven-storey shear building model with four different damage cases under earthquake excitations is used in the numerical studies. In experimental verifications, data from shake table tests on a 12-storey scaled reinforced concrete frame structure with different earthquake excitations are analyzed with the proposed approach. The results in both numerical studies and experimental validations demonstrate that the proposed approach can be successfully applied for nonlinear structural damage identification.

In this paper we propose a new approach for forecasting the cryptocurrency time series, which combines the fuzzy transform and the fuzzy inference system. We also test whether fuzzy transform yields better results forecasting results in comparison to Fourier transform. Finally, we will investigate whether fuzzy rules used in fuzzy inference system can successfully capture high and low volatility moments in the time series, as well as high correlations between the three different cryptocurrencies.

Traffic accidents are extremely rare, creating the need for surrogate methods for safety analysis that makes efficient use of the information provided by traffic conflicts, which also are limited in availability. The severity measure time-to-collision (TTC) in combination with extreme value theory have so far been one of the primary measures used to infer traffic safety levels, but it relies on unrealistic assumptions that results in severity measures that do not always agree well with observed danger. Stochastic TTC has been proposed as an alternative, which replaces the constant velocity trajectories used to define collision course with naturalistic ones, resulting in a distribution of potential TTC values. The main focus of this thesis is to find a way to mathematically model such data. Stochastic TTC is conceptualized within the framework of mixed distributions, and equations allowing for extreme value theory to be used in such a context are derived. A second point of focus is on presenting a new method for estimating the collision probability, allowing for separate estimation of collisions that occurred with and without attempts at evasive action. Also, the effects of data-transforms were investigated in a simulation setting, which proved highly useful in reducing the tendency for underestimation which seems to be a common problem when extreme value theory is applied to traffic data, and overall improving accuracy. Stochastic TTC and the proposed methods were also tested in this simulated traffic environment, which showed that stochastic TTC can work at least as well as regular TTC, but in order for more significant differences to be seen, the simulation would have to contain more variable road user behavior and more curved trajectories.

Surfing in rough waters is not always as fun as wave riding the “big one”. Similarly, in optimization problems, fitness landscapes with a huge number of local optima make the search for the global optimum a hard and generally annoying game. Computational Intelligence optimization metaheuristics use a set of individuals that “surf” across the fitness landscape, sharing and exploiting pieces of information about local fitness values in a joint effort to find out the global optimum. In this context, we designed surF, a novel surrogate modeling technique that leverages the discrete Fourier transform to generate a smoother, and possibly easier to explore, fitness landscape. The rationale behind this idea is that filtering out the high frequencies of the fitness function and keeping only its partial information (i.e., the low frequencies) can actually be beneficial in the optimization process. We prove our theory by combining surF with a settings free variant of Particle Swarm Optimization (PSO) based on Fuzzy Logic, called Fuzzy Self-Tuning PSO. Specifically, we introduce a new algorithm, named F3ST-PSO, which performs a preliminary exploration on the surrogate model followed by a second optimization using the actual fitness function. We show that F3ST-PSO can lead to improved performances, notably using the same budget of fitness evaluations.

The capacity of the downlink channel is a major bottleneck for applications based on remote sensing hyperspectral imagery (HSI). Data compression is an essential tool to maximize the amount of HSI scenes that can be retrieved on the ground. At the same time, energy and hardware constraints of spaceborne devices impose limitations on the complexity of practical compression algorithms. To avoid any distortion in the analysis of the HSI data, only lossless compression is considered in this study. This work aims at finding the most advantageous compression–complexity trade-off within the state of the art in HSI compression. To do so, a novel comparison of the most competitive spectral decorrelation approaches combined with the best performing low-complexity compressors of the state is presented. Compression performance and execution time results are obtained for a set of 47 HSI scenes produced by 14 different sensors in real remote sensing missions. Assuming only a limited amount of energy is available, obtained data suggest that the FAPEC algorithm yields the best trade-off. When compared to the CCSDS 123.0-B-2 standard, FAPEC is 5.0 times faster and its compressed data rates are on average within 16% of the CCSDS standard. In scenarios where energy constraints can be relaxed, CCSDS 123.0-B-2 yields the best average compression results of all evaluated methods.

Column-averaged dry-air mole fractions of carbon dioxide (XCO2) and methane (XCH4) measured by a solar viewing portable Fourier transform spectrometer (FTS, EM27/SUN) have been characterized and validated by comparison using in situ profile measurements made during the transfer flights of two aircraft campaigns: Korea-United States Air Quality Study (KORUS-AQ) and Effect of Megacities on the Transport and Transformation of Pollutants at Regional and Global Scales (EMeRGe). The aircraft flew over two Total Carbon Column Observing Network (TCCON) sites: Rikubetsu, Japan (43.46∘ N, 143.77∘ E), for the KORUS-AQ campaign and Burgos, Philippines (18.53∘ N, 120.65∘ E), for the EMeRGe campaign. The EM27/SUN was deployed at the corresponding TCCON sites during the overflights. The mole fraction profiles obtained by the aircraft over Rikubetsu differed between the ascending and the descending flights above approximately 8 km for both CO2 and CH4. Because the spatial pattern of tropopause heights based on potential vorticity values from the ERA5 reanalysis shows that the tropopause height over the Rikubetsu site was consistent with the descending profile, we used only the descending profile to compare with the EM27/SUN data. Both the XCO2 and XCH4 derived from the descending profiles over Burgos were lower than those from the ascending profiles. Output from the Weather Research and Forecasting Model indicates that higher CO2 for the ascending profile originated in central Luzon, an industrialized and densely populated region about 400 km south of the Burgos TCCON site. Air masses observed with the EM27/SUN overlap better with those from the descending aircraft profiles than those from the ascending aircraft profiles with respect to their properties such as origin and atmospheric residence times. Consequently, the descending aircraft profiles were used for the comparison with the EM27/SUN data. The EM27/SUN XCO2 and XCH4 data were derived by using the GGG2014 software without a

We revisited the formalism of 110 polarized scattering equation by Geyer and Mason from the perspective of spinor frame approach and spinor moving frame formulation of the 110 ambitwistor superstring action. In particular, we rigorously obtain the equation for the spinor function on Riemann sphere from the supertwistor form of the ambitwistor superstring action, write its general solution and use it to derive the polarized scattering equation. We show that the expression used by Geyer and Mason to motivate their ansatz for the solution of polarized scattering equation can be obtained from our solution after a suitable gauge fixing. To this end we use the hidden gauge symmetries of the 110 ambitwistor superstring, including S0(16), and the description of ambitwistor superstring as a dynamical system in an 110 superspace enlarged by bosonic directions parametrized by 517 tensorial central charge coordinates Z mu nu and Z mu nu rho sigma kappa. We have also found the fermionic superpartner of the polarized scattering equation. This happens to be a differential equation in fermionic variables imposed on the super amplitude, rather then just a condition on the scattering data as the bosonic polarized scattering equation is. D=10 case is also discussed stressing the similarities and differences with 110 systems. The useful formulation of 100 ambitwistor superstring considers it as a dynamical system in superspace enlarged with 126 tensorial central charge coordinates Z(mu nu rho sigma kappa).

The presence of branching vessels, a wide aneurysm neck, and/or fusiform morphology represents a challenge to conventional endovascular treatment of visceral artery aneurysms. A variety of techniques and devices have emerged for the treatment of intracranial aneurysms, in which more aggressive treatment algorithms aimed at smaller and morphologically diverse aneurysms have driven innovation. Here, modified neurointerventional techniques including the use of compliant balloons, scaffold- or stent-assisted coil embolization, and flow diversion are described in the treatment of visceral aneurysms. Neurointerventional devices and their mechanisms of action are described in the context of their application in the peripheral arterial system.Copyright © 2019 SIR

Today, the main research field for the automotive industry is to find solutions for active safety. In order to perceive the surrounding environment, tracking nearby traffic objects plays an important role. Validation of the tracking performance is often done in staged traffic scenarios, where additional sensors, mounted on the vehicles, are used to obtain their true positions and velocities. The difficulty of evaluating the tracking performance complicates its development. An alternative approach studied in this thesis, is to record sequences and use non-causal algorithms, such as smoothing, instead of filtering to estimate the true target states. With this method, validation data for online, causal, target tracking algorithms can be obtained for all traffic scenarios without the need of extra sensors. We investigate how non-causal algorithms affects the target tracking performance using multiple sensors and dynamic models of different complexity. This is done to evaluate real-time methods against estimates obtained from non-causal filtering. Two different measurement units, a monocular camera and a LIDAR sensor, and two dynamic models are evaluated and compared using both causal and non-causal methods. The system is tested in two single object scenarios where ground truth is available and in three multi object scenarios without ground truth. Results from the two single object scenarios shows that tracking using only a monocular camera performs poorly since it is unable to measure the distance to objects. Here, a complementary LIDAR sensor improves the tracking performance significantly. The dynamic models are shown to have a small impact on the tracking performance, while the non-causal application gives a distinct improvement when tracking objects at large distances. Since the sequence can be reversed, the non-causal estimates are propagated from more certain states when the target is closer to the ego vehicle. For multiple object tracking, we find that correct as

This bachelors thesis presents a vision based control system for the quadrotor aerial vehicle,Crazy ie 2.0, developed by Bitcraze AB. The main goal of this thesis is to design andimplement an o-board control system based on visual input, in order to control the positionand orientation of the vehicle with respect to a single ducial marker. By integrating a cameraand wireless video transmitter onto the MAV platform, we are able to achieve autonomousnavigation and landing in relatively close proximity to the dedicated target location.The control system was developed in the programming language Python and all processing ofthe vision-data take place on an o-board computer. This thesis describes the methods usedfor developing and implementing the control system and a number of experiments have beencarried out in order to determine the performance of the overall vision control system. Withthe proposed method of using ducial markers for calculating the control demands for thequadrotor, we are able to achieve autonomous targeted landing within a radius of 10centimetres away from the target location., I detta examensarbete presenteras ett visionsbaserat kontrollsystem for dronaren Crazy ie 2.0som har utvecklats av Bitcraze AB. Malet med detta arbete ar att utforma och implementeraett externt kontrollsystem baserat pa data som inhamtas av en kamera for att reglera fordonetsposition och riktning med avseende pa en markor placerad i synfaltet av kameran. Genom attintegrera kameran tillsammans med en tradlos videosandare pa plattformen, visar vi i dennaavhandling att det ar mojligt att astadkomma autonom navigering och landning i narheten avmarkoren.Kontrollsystemet utvecklades i programmeringsspraket Python och all processering avvisions-datan sker pa en extern dator. Metoderna som anvands for att utvecklakontrollsystemet och som beskrivs i denna rapport har testats under ett ertal experiment somvisar pa hur val systemet kan detektera markoren och hur val de olika ingaendekomponenterna samspelar for att kunna utfora den autonoma styrningen. Genom den metodsom presenteras i den har rapporten for att berakna styrsignalerna till dronaren med hjalp avvisuell data, visar vi att det ar mojligt att astadkomma autonom styrning och landning motmalet inom en radie av 10 centimeter.