Precision Agriculture without borders: Practical issues and improvements in farmland coverage with aerial vehicles.

This work presents a solution for the aerial coverage of a field by using a fleet of aerial vehicles. The use of Unmanned Aerial Vehicles allows to obtain high resolution mosaics to be used in Precision Agriculture techniques. This report is focus on providing a solution for the full simultaneous coverage problem taking into account restrictions as the required spatial resolution and overlap while maintaining similar light conditions and safety operation of the drones. Results obtained from real field tests are finally reported

Land cover dynamics and climate change implications on water resources in South Pacific Costa Rica

Water is fundamental to human life and the availability of freshwater is often a constraint on human welfare and economic development. Consequently, the potential effects of global changes on hydrology and water resources are considered among the most severe and vital ones. Water scarcity is one of the main problems in the rural communities of Central America, as a result of an important degradation of catchment areas and the over-exploitation of aquifers. The present Thesis is focused on two critical aspects of global changes over water resources: (1) the potential effects of climate change on water quantity and (2) the impacts of land cover and land use changes on the hydrological processes and water cycle. Costa Rica is among the few developing countries that have recently achieved a land use transition with a net increase in forest cover. Osa Region in South Pacific Costa Rica is an appealing study site to assess water supply management plans and to measure the effects of deforestation, forest transitions and climate change projections reported in the region. Rural Community Water Supply systems (ASADAS) in Osa are dealing with an increasing demand of freshwater due to the growing population and the change in the way of life in the rural livelihoods. Land cover mosaics which have resulted from the above mentioned processes are characterized by the abandonment of marginal farmland with the spread over these former grasslands of high return crops and the expansion of secondary forests due to reforestation initiatives. These land use changes have a significant impact on runoff generation in priority water-supply catchments in the humid tropics, as evidenced by the analysis of the Tinoco Experimental Catchment in the Southern Pacific area of Costa Rica. The monitoring system assesses the effects of the different land uses on the runoff responses and on the general water cycle of the basin. Runoff responses at plot scale are analyzed for secondary forests, oil palm plantations, forest plantations and grasslands. The Oil palm plantation plot presented the highest runoff coefficient (mean RC=32.6%), twice that measured under grasslands (mean RC=15.3%) and 20-fold greater than in secondary forest (mean RC=1.7%). A Thornthwaite-type water balance is proposed to assess the impact of land cover and climate change scenarios over water availability for rural communities in Osa Region. Climate change projections were obtained by the downscaling of BCM2, CNCM3 and ECHAM5 models. Precipitation and temperature were averaged and conveyed by the A1B, A2 and B1 IPCC climate scenario for 2030, 2060 and 2080. Precipitation simulations exhibit a positive increase during the dry season for the three scenarios and a decrease during the rainy season, with the highest magnitude (up to 25%) by the end of the 21st century under scenario B1. Monthly mean temperature simulations increase for the three scenarios throughout the year with a maximum increase during the dry season of 5% under A1B and A2 scenarios and 4% under B1 scenario. The Thornthwaite-type Water Balance model indicates important decreases of water surplus for the three climate scenarios during the rainy season, with a maximum decrease on May, which under A1B scenario drop up to 20%, under A2 up to 40% and under B1 scenario drop up to almost 60%. Land cover scenarios were created taking into account current land cover dynamics of the region. Land cover scenario 1 projects a deforestation situation, with forests decreasing up to 15% due to urbanization of the upper catchment areas; land cover scenario 2 projects a forest recovery situation where forested areas increase due to grassland abandonment on areas with more than 30% of slope. Deforestation scenario projects an annual water surplus decrease of 15% while the reforestation scenario projects a water surplus increase of almost 25%. This water balance analysis indicates that climate scenarios are equal contributors as land cover scenarios to future water resource estimations.

An interactive web-based learning assistant for structural analysis of continuous beams

There are significant levels of concern about the relevance and the difficulty of learning some issues on Strength of Materials and Structural Analysis. Most students of Continuum Mechanics and Structural Analysis in Civil Engineering usually point out some key learning aspects as especially difficult for acquiring specific skills. These key concepts entail comprehension difficulties but ease access and applicability to structural analysis in more advanced subjects. Likewise, some elusive but basic structural concepts, such as flexibility, stiffness or influence lines, are paramount for developing further skills required for advanced structural design: tall buildings, arch-type structures as well as bridges. As new curricular itineraries are currently being implemented, it appears appropriate to devise a repository of interactive web-based applications for training in those basic concepts. That will hopefully train the student to understand the complexity of such concepts, to develop intuitive knowledge on actual structural response and to improve their preparation for exams. In this work, a web-based learning assistant system for influence lines on continuous beams is presented. It consists of a collection of interactive user-friendly applications accessible via Web. It is performed in both Spanish and English languages. Rather than a “black box” system, the procedure involves open interaction with the student, who can simulate and virtually envisage the structural response. Thus, the student is enabled to set the geometric, topologic and mechanic layout of a continuous beam and to change or shift the loading and the support conditions. Simultaneously, the changes in the beam response prompt on the screen, so that the effects of the several issues involved in structural analysis become apparent. The system is performed through a set of web pages which encompasses interactive exercises and problems, written in JavaScript under JQuery and DyGraphs frameworks, given that their efficiency and graphic capabilities are renowned. Students can freely boost their self-study on this subject in order to face their exams more confidently. Besides, this collection is expected to be added to the "Virtual Lab of Continuum Mechanics" of the UPM, launched in 2013 (http://serviciosgate.upm.es/laboratoriosvirtuales/laboratorios/medios-continuos-en-construcci%C3%B3n)

Changes in Petrophysical Properties of the Stone Surface due to Past Conservation Treatments in Archaeological Sites of Merida (Spain)

Petrophysical properties, such as porosity, permeability, density or anisotropy de-termine the alterability of stone surfaces from archaeological sites, and therefore, the future preservation of the material. Others, like superficial roughness or color, may point out changes due to alteration processes, natural or man-induced, for ex-ample, by conservation treatments. The application of conservation treatments may vary some of these properties forcing the stone surface to a re-adaptation to the new conditions, which could generate new processes of deterioration. In this study changes resulting from the application of consolidating and hydrophobic treatments on stone materials from the Roman Theatre (marble and granite) and the Mitreo’s House (mural painting and mosaics), both archaeological sites from Merida (Spain), are analyzed. The use of portable field devices allows us to perform analyses both on site and in la-boratory, comparing treated and untreated samples. Treatments consisted of syn-thetic resins, consolidating (such as tetraethoxysilane TEOS) and hydrophobic products. Results confirm that undesirable changes may occur, with consequences ranging from purely aesthetic variations to physical, chemical and mechanical damages. This also permits us to check limitations in the use of these techniques for the evaluation of conservation treatments.

On the acquisition of high-resolution maps with open source software and commercials off-the-shelf quad-rotors

Mosaics are high-resolution images obtained aerially and employed in several scientific research areas, such for example, in the field of environmental monitoring and precision agriculture. Although many high resolution maps are obtained by commercial demand, they can also be acquired with commercial aerial vehicles which provide more experimental autonomy and availability. For what regard to mosaicing-based aerial mission planners, there are not so many - if any - free of charge software. Therefore, in this paper is presented a framework designed with open source tools and libraries as an alternative to commercial tools to carry out mosaicing tasks.

A framework for adaptive e-learning for continuum mechanics and structural analysis

This paper presents a project for providing the students of Structural Engineering with the flexibility to learn outside classroom schedules. The goal is a framework for adaptive E-learning based on a repository of open educational courseware with a set of basic Structural Engineering concepts and fundamentals. These are paramount for students to expand their technical knowledge and skills in structural analysis and design of tall buildings, arch-type structures as well as bridges. Thus, concepts related to structural behaviour such as linearity, compatibility, stiffness and influence lines have traditionally been elusive for students. The objective is to facilitate the student a teachinglearning process to acquire the necessary intuitive knowledge, cognitive skills and the basis for further technological modules and professional development in this area. As a side effect, the system is expected to help the students improve their preparation for exams on the subject. In this project, a web-based open-source system for studying influence lines on continuous beams is presented. It encompasses a collection of interactive user-friendly applications accessible via Web, written in JavaScript under JQuery and Dygraph Libraries, taking advantage of their efficiency and graphic capabilities. It is performed in both Spanish and English languages. The student is enabled to set the geometric, topologic, boundary and mechanic layout of a continuous beam. While changing the loading and the support conditions, the changes in the beam response prompt on the screen, so that the effects of the several issues involved in structural analysis become apparent. This open interaction with the user allows the student to simulate and virtually infer the structural response. Different levels of complexity can be handled, whereas an ongoing help is at hand for any of them. Students can freely boost their experiential learning on this subject at their own pace, in order to further share, process, generalize and apply the relevant essential concepts of Structural Engineering analysis. Besides, this collection is being added to the "Virtual Lab of Continuum Mechanics" of the UPM, launched in 2013 (http://serviciosgate.upm.es/laboratoriosvirtuales/laboratorios/medios-continuos-en-construcci%C3%B3n)

El vidrio y sus máscaras : el sueño de la arquitectura de cristal

Según Heidegger, la esencia de la arquitectura, de la construcción, descansa en un no espacio: en la materia con que se construyen las fronteras que otorgan espacios, irradiando sobre ellos aquello que los caracteriza. Si hay alguna materia, de las utilizadas por la arquitectura a lo largo de su historia para construir fronteras, que haya mantenido una especial relación con la luz y la visión, dando un carácter inconfundible a los espacios aviados por ellas, esta es el vidrio; algunas de las etimologías de su nombre: zakû (ser claro), hyalos (diáfano) o vitrum (ver), así lo evidencian. Posiblemente, sea la pregnancia de este modo fascinante de relacionarse con la luz, la que ha hecho del vidrio, a lo largo del tiempo que lleva siendo usado en arquitectura, y aún antes, el material que ha provocado en el imaginario humano la ilusión de ser aquel en que, en último término, podrían llegar a sublimarse todos los demás, dando lugar con ello a lo que en la tesis hemos denominado el sueño de la arquitectura de cristal. Siendo la luz, siempre, energía, consideraremos en la tesis luz-energía, a aquella que ilumina y calienta; es una luz científica y mesurable. Cuando la luz se “hace visible”, desvelando un mensaje “contenido” en el vidrio, hablaremos de luz-información. Esta luz, no puede medirse científicamente. La luz-energía y la luz-información, se manifiestan al conjuro de la arquitectura de vidrio. Es la segunda la que ha conformado las fronteras de vidrio enmascarado, y la que se estudia con más detenimiento en la tesis. Los distintos modos de usar en arquitectura la infinita combinatoria de las propiedades de absortancia, reflectancia, transmitancia y translucencia del vidrio, ha condicionado al hombre en su manera de “ver” el mundo. Unas veces, “inmerso” en él, puesto que solo lo separa del mismo, una frontera transparente, y “deseadamente” invisible: ese modo de usar el vidrio, ha sido el sueño imposible de una parte importante de la arquitectura del siglo XX. Otras veces, para “aislarse” de él, el hombre ha manipulado la luz y el vidrio para construir mundos diferentes. Las fronteras de vidrio enmascarado de color, mosaicos, vidrieras, pantallas y lo que hemos llamado vidrios complejos (con un cometido similar al que Schiller atribuía al coro en la tragedia griega, aislar a esta del “mundo real”, para mantener su libertad poética), son las fronteras que han construido el sueño posible de la arquitectura de cristal. Ambas actitudes, en distintos momentos de la historia de la arquitectura, han sido dos formas de querer materializar un mismo sueño. La capacidad del vidrio para adaptarse a tantos modos de presentarse ante nosotros, y a poder ser interpretado de tantas formas diferentes, es la que ha servido para dar título a la tesis, pues hasta en su faceta más transparente, el vidrio, de una forma o de otra, se ha mostrado siempre como un material enmascarado en el más amplio sentido de la palabra: se enmascara, incluso cuando apela a la transparencia o se convierte en espejo, para hacernos caer en la ilusión de que no está presente. Cuando el hombre construyó fronteras de vidrio e incluso antes, cuando soñó que con él podría llegar a construirlas, condensó en ellas toda la mítica, la mística y la epistemología en torno a la luz y la visión, dando lugar a una serie de arquetipos arquitectónicos. En la iglesia bizantina, la luz sobre, o la luz desde, los mosaicos, construyó una frontera titilante; y en la catedral gótica, la luz a través de las vidrieras construyó una frontera radiante; en ambos casos con el fin de alcanzar anagógicamente lo Inteligible. En el siglo XIX, con el descubrimiento de la electricidad y su incorporación a la arquitectura, las fronteras se vuelven fulgurantes, aviando, en este caso, el espacio urbano. Poco antes, en este mismo siglo, el espíritu del gótico tiene un efímero resurgir del que se nutrirá, a comienzos del siglo XX, el expresionismo cristalino, en el que la luz anagógica se hace laica. El espacio urbano fulgurante prefigurado por este movimiento y presente en las ciudades desde principios del siglo XX, fue potenciado a mediados de ese siglo con la aparición de las pantallas, extendiéndose desde entonces, imparable, por todo el planeta. La reciente emergencia de los vidrios complejos, ha abierto la posibilidad de construir fronteras a la carta (de vidrios de propiedades múltiples, seleccionadas de forma voluntaria y variable en cada momento). En principio, se pensó que, el uso de estos vidrios como cerramiento, podría llegar a constituirse como la panacea de los problemas del material relacionados con la luz-energía, sin necesidad de recurrir a “prótesis”, y manteniendo por tanto la seductora tersura de la fachada; aunque parece que, por ahora, esa posibilidad es, cuando menos, lejana. Sin embargo, en el campo de las megapantallas urbanas (y ,en general, en el de las pantallas de información), ubicuas actualmente en nuestras vidas, los vidrios complejos ayudan a construir los espesos velos de ilusión, que según Lefebvre sirven para mantener el capitalismo, siendo el último estadio de un desarrollo tecnológico, impuesto por el principio de economía del hombre, que como un metrónomo inexorable, y a modo de contrapunto, ha acompañado siempre (de nuevo en palabras de Lefebvre), a la necesidad del gasto, del juego, de la lucha, del arte, de la fiesta. La tecnología y el arte forman parte de la cultura producida por la sociedad y como señala Lévi-Strauss, esa cultura imprime orden; por el contrario, la sociedad, entendida como el conjunto de relaciones que los hombres mantienen entre sí, produce desorden. Del equilibrio entre esos extremos, surge el progreso, incluido el de la arquitectura. Las fronteras de vidrio que analizamos en la tesis –que avían espacios para la espiritualidad, el fasto y el espectáculo o, desde otro punto de vista, para las distintas manifestaciones del poder: la iglesia, la monarquía, el estado o el mercado– también han surgido de esa concomitancia entre el desorden y el orden; y forma parte de ese desorden, la aventura que ha impulsado al genio individual de místicos, alquimistas, geómetras, abades, reyes, inventores, poetas y arquitectos, a explorar, como escribe Apollinaire, vastos y extraños territorios donde el misterio en flor, se ofrece a quien quiera cogerlo, hogueras nuevas de colores nunca vistos, mil fantasmas imponderables a los que dar cuerpo. ABSTRACT According to Heidegger, the essence of architecture, building, lies in a non-space: the material that creates the boundaries from which something begins its presencing, radiating onto them that which characterizes them. If there is any single material amongst all those used throughout the history of architecture to build boundaries which has maintained a special relationship with light and vision, which has bestowed a distinctive character on spaces avid for them, it is glass. This is evidenced in some of its etymologies: zakû (to be clear), hyalos (transparent), vitrum (see). The rich potential of this fascinating way of relating to light in the history of the architectural use of glass, and even before, is possibly what has triggered the illusion in human imagination of being something that can ultimately sublimate all others, giving rise to what in this thesis we call The Dream of Crystal Architecture. Given that light is always energy, in this thesis we consider energy-light to be that which illuminates and warms. This is scientific, measurable light. When light "becomes visible" and reveals a message “contained” in glass, we speak of information-light. This light cannot be measured scientifically. Energy-light and information-light are manifested under the spell of glass architecture. The latter is what has shaped the boundaries of coloured glass, which is studied in this thesis. Architecture's different ways of using the infinite combinations of the absorptance, reflectance, transmittance and translucency of glass has affected the way we humans "see" the world. Sometimes we are "immersed" in it, since only an invisible, transparent boundary separates us from it: this use of glass has characterized a considerable part of 20th century architecture. In other cases, in order to "isolate" us from it, we have manipulated light and glass to build different worlds: the boundaries of glass "masked" by colour, mosaics, stained glass, screens and what we have called complex glazing, which plays a similar role to what Schiller attributed to the chorus in Greek tragedy, isolating it from the "real world" in order to maintain its poetic license. These are the boundaries that have built the viable dream of crystal architecture. These two approaches have been different ways of making same dream come true at different times in the history of architecture. The ability of glass to adapt to so many forms of manifestation, and interpretation, is what has given rise to the title of the thesis. Even in its most transparent facet, glass has one way or another always been a masking material in the broadest sense of the word: it is masked even when it invites transparency or becomes a mirror, triggering the illusion that it is not present. When man began to build glass boundaries, and even before, when he dreamed that he could build them, he condensed in them all the mythology, mysticism and epistemology concerning light and vision, which gave rise to a series of architectural archetypes. In the Byzantine church, light on or from mosaics created tenuous boundaries. In Gothic cathedrals, the light through the stained glass windows constructed radiant boundaries. In both cases the aim was to achieve, in an anagogical way, the Intelligible. In the 19th, the discovery of electricity and its use in architecture led to the production of dazzling boundaries, in this case employed in urban spaces. Earlier in the same century, the Gothic spirit had a short-lived revival, which in the early 20th century drew from crystalline expressionism in which anagogic light became secular. The dazzling urban space prefigured by this movement, present in cities since the early 20th century, was intensified in the mid-century with the emergence of screens, and since then it has spread unstoppably across the world. The recent emergence of complex glasses has made it possible to build boundaries on demand in glass with multiple properties, chosen at will and at whim at any time. Initially it was thought that the use of this glass as a wall could eventually become the panacea for the material problems related to energy-light, without needing to resort to "prosthesis" and thereby maintain the seductive smoothness of the facade. For now, that possibility seems remote, to say the least. In the realm of urban megascreens and information screens in general, now ubiquitous in our lives, complex glasses help to build the thick veils of illusion which, according to Lefebvre, serve to maintain capitalism. Like an inexorable metronome, in counterpoint, this ultimate state of technological development imposed by man's principle of economy has in fact always accompanied (again in the words of Lefebvre), the need to spend, play, fight, art, and party. Technology and art are part of the culture produced by society. As Levi-Strauss says, this culture imposes order. On the contrary, society, understood as a set of relationships amongst people, produces disorder. Progress, including that of architecture, arises from the balance between these two extremes. The glass boundaries analyzed in this thesis, which propitiate spaces for spirituality, pomp and spectacle or, from a different perspective, for the various manifestations of power: the church, the monarchy, the state and the market, have also emerged from the concomitance of order and disorder. One aspect of this disorder is the adventure that has inspired the individual genius of mystics, alchemists, surveyors, abbots, kings, inventors, poets and architects to explore, as Apollinaire says, vast, strange domains where flowering mystery offers itself to whoever wishes to pluck it, new fires, colours you have never seen before, a thousand intangible phantasms still awaiting reality.