612 research outputs found

    A mixed-signal integrated circuit for FM-DCSK modulation

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    This paper presents a mixed-signal application-specific integrated circuit (ASIC) for a frequency-modulated differential chaos shift keying (FM-DCSK) communication system. The chip is conceived to serve as an experimental platform for the evaluation of the FM-DCSK modulation scheme, and includes several programming features toward this goal. The operation of the ASIC is herein illustrated for a data rate of 500 kb/s and a transmission bandwidth in the range of 17 MHz. Using signals acquired from the test platform, bit error rate (BER) estimations of the overall FM-DCSK communication link have been obtained assuming wireless transmission at the 2.4-GHz ISM band. Under all tested propagation conditions, including multipath effects, the system obtains a BER = 10-3 for Eb/No lower than 28 dB.Ministerio de Ciencia y Tecnología TIC2003-0235

    Controversy between curriculum design and curriculum development of online "highly specialized" education in the field of construction

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    Nowadays, on a global level, the Higher Education System has a complex and broad horizon of curricular tools to use in the teaching and learning process. In addition to these new educational instruments, full of possibilities, we face specific socio-economic conditions that affect in a significantly way the Curriculum Development in certain knowledge areas (areas traditionally built on a methodology based on a physical presence of students in the classroom). Some areas such as Restoration, Rehabilitation or Construction Pathologies, and the construction sector in general, require very defined and particular knowledge that only a small number of experts claim as specialized training. All these aspects condition the teaching methodology performed in a physical classroom at a university campus (the only option used until recent years) and made us consider the integration of online teaching in these areas too. The present work shows the teaching methodology used for the development of two online courses, where we offer distance learning for "highly specialized" formation in the Edification area (an area where traditionally there was only classroom training). At the beginning, both courses were designed by classroom training, but got a really small number of applications due to the specialized topic proposed. Later, we proposed a "Curriculum Redesign" of the contents, offering an online modality, which implied a significant demand both within and outside the university area. A notable feature of this educational experience is the great spectrum opened for attendees of both courses in the online version. This situation improved significantly the "Curriculum Development" for the student and implied an interesting new proposal on the offered contents and materials (what would have been really difficult to get in a face to face classroom). In conclusion, the absence of certain types of specialized contents in the academic university curricula makes essential to raise new methodologies to save the gap in this area through additional training courses as those analyzed in this paper. Thus, our experience opens a debate on the appropriateness of implementing online training in relation to the face to face training in constructive content subjects and, especially, presents a new scheme, not without controversy, for the curriculum design

    Teaching-learning process of historical heritage: a Journey as a beginning, path and end

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    The implantation of new university degrees within the European Higher Education Area implies the need of innovative methodologies in teaching and learning to improve the skills and competencies of students and to answer the growing needs that society continuously demands to heritage management experts. The present work shows an application of the teaching methodology proposed during the international workshop entitled “I International Planning Preservation Workshop. Learning from Al Andalus”, which included the participation of the University of Alicante and Granada, Università Politecnico di Milano and Hunter College City University of New York; where we tried to dissolve traditional boundaries derived of interuniversity cooperation programs. The main objective of the workshop was to discuss and debate the role of urban Historical Centers within the Global Heritage by the integrated work through multidisciplinary teams and the creation of a permanent international working group between these universities to both teach and research. The methodology of this workshop was very participatory and considered the idea of a new learning process generated by "a journey experience." A trip from global to local (from the big city to the small village) but also a trip from the local (historical) part of a big city to the global dimension of contemporary historical villages identified by the students through a system of exhibition panels in affinity groups, specific projects proposed by lecturers and teachers or the generation of publications in various areas (texts, photographs, videos, etc.). So, the participation of the students in this multidisciplinary meeting has enhanced their capacity for self-criticism in several disciplines and has promoted their ability to perform learning and research strategies in an autonomous way. As a result, it has been established a permanent international work structure for the development of projects of the Historical City. This relationship has generated the publication of several books whose contents have reflected the conclusions developed in the workshop and several teaching proposals shared between those institutions. All these aspects have generated a new way of understanding the teaching process through a journey, in order to study the representative role of university in the historical heritage and to make students (from planning, heritage management, architecture, geography, sociology, history or engineering areas) be compromised on searching strategies for sustainable development in the Contemporary City

    The Havana Capitol, geometry and proportion through its original plans

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    [EN] The research on the National Capitol Building in Havana, Cuba, aims to study the building and its constructive solutions and materials, by means of the extensive graphic and photographic documentation preserved in the archives of the city. This documentation is a rigorous source of technical information, useful for analyzing the building in detail and understanding and dating its different construction phases. The research was developed in the city of Havana, Cuba, in the last five years in coordination with the Office of the City Historian, and it allowed creating a significant collection of plans, images and other graphic documents as a basis for future research. This article focuses on analyzing the work from its original plans (geometry and proportion, techniques of representation and graphic quality), which are a work of art by themselves, a meticulous handwork done by several Cuban architects and engineers. These documents have never seen the light until now.[ES] El objetivo de la investigación realizada en el Capitolio de La Habana se centra en estudiar el edificio, sus soluciones constructivas y materiales, en base a la extensa documentación gráfica y fotográfica existente en los diferentes archivos de la ciudad. Esta documentación constituye una fuente rigurosa de información técnica, útil para analizar en detalle el edificio y comprender y datar sus diferentes fases constructivas. La investigación ha sido desarrollada en La Habana, Cuba, durante los últimos cinco años en coordinación con la Oficina del Historiador de la Ciudad y ha permitido crear un archivo de planos, imágenes, y otros documentos gráficos como base de futuras investigaciones. Este artículo se centra en analizar la obra a partir de sus planos originales (geometría y proporción, técnicas de representación, calidad gráfica), que son una obra de arte en sí mismos y que nunca hasta ahora han visto la luz. Se trata de un minucioso trabajo realizado a mano por varios arquitectos e ingenieros cubanos.Mestre Martí, M.; Jiménez Delgado, A.; Ródenas López, M.; Jiménez Vicario, PM. (2018). El Capitolio de La Habana, geometría y proporción a través de sus planos originales. EGA. Revista de Expresión Gráfica Arquitectónica. 23(33):40-51. doi:10.4995/ega.2018.8859SWORD40512333DE LAS CUEVAS TORAYA, J. , (2001) . 500 years of construction in Cuba . Havana: Chavin. Servicios Gráficos y Editoriales, SLTHE ARCHITECT, (1933). No. 38. "The Capitol seen by an Architect ". The Architect, no. 38, p. 352FERNÁNDEZ, P. y Cía , (1933). The Book of the Capitol . Havana.SECRETARIAT OF PUBLIC WORKS (1931) . Inventory of non-consumable property of the Capitol. Havana: Ministry of Public Works.VEGA BOLAÑO, E., (2010). Diagnostic study of the cover of the National Capitol . Project of unpublished degree. Directors: MSc. Ing. Frank Díaz Alemán; Dr. Eng. OdalysÁlvarez Rodríguez. Havana: José Antonio Echevarría Polytechnic Higher Institute. School of Civil Engineering

    Análisis de los factores genéticos y ambientales con influencia en la circunferencia escrotal en el vacuno de carne de Raza Retinta

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    De los caracteres del vacuno de carne, los relacionados con la eficiencia reproductiva han sido considerados de una importancia fundamental. Dentro de éstos, cabe destacar la CE, parámetro correlacionado positivamente con las características cualitativas y cuantitativas del semen, asl como asociado a parámetros reproductivos en hembras (precocidad sexual y fertilidad). En este trabaja se ha estudiado la CE desde distintos aspectos como los factores ambientales que le influyen, su evolución a lo largo del tiempo, el cálculo del parámetro genético de la heredabilidad y las relaciones con otras variables como el peso vivo del animal. Para ello, se realizaron 1.020 mediciones en 281 animales pertenencientes a 20 ganaderías del núcleo de Control del plan de mejora de esta raza. la media obtenida para la circunferencia escrotal fue de 30,66 ± 0, 166 (CV. = 17,3%)y 34,38 ± 0, 140 (C.V.= 9, 1%) para an ima les de un año de edad, y la heredabilidad estimada para este carácter de 0,36. El peso vivo, y en segundo lugar la edad, fueron las dos variables con mayor influencia en la circunferencia escrotal en esta raza. Otros factores ambientales a tener en cuenta en los análisis genéticos de esta variable son la ganadería y año -estación de medida-, cuyo efecto se ha mostrado altamente significativo. Así si bien la curva de crecimiento de la CE que mejor se ajusta al intervalo de crecimiento analizado fue la logistítica 2, a efectos prácticos de tipificac ión al año, consideramos que la curva polinómica de segundo grado da un ajuste equivalente, permitienndo una mayor simplificación de los cálculos necesarios para su aplicación en un plan de mejora

    On the Reusability of User Interface Declarative Models

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    The automatic generation of user interfaces based on declarative models achieves a significant reduction of the development effort. In this paper, we analyze the feasibility of using two well-known techniques such as XInclude and Packaging in the new context of reusing user-interface model specifications. After analyzing the suitability of each technique for UI reutilization and implementing both techniques in a real system, we show that both techniques are suited to be used within the context of today’s existing model-based user interfaces

    Reusing UI elements with Model-Based User Interface Development

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    This paper introduces the potential for reusing UI elements in the context of Model-Based UI Development (MBUID) and provides guidance for future MBUID systems with enhanced reutilization capabilities. Our study is based upon the development of six inter-related projects with a specific MBUID environment which supports standard techniques for reuse such as parametrization and sub-specification, inclusion or shared repositories. We analyze our experience and discuss the benefits and limitations of each technique supported by our MBUID environment. The system architecture, the structure and composition of UI elements and the models specification languages have a decisive impact on reusability. In our case, more than 40% of the elements defined in the UI specifications were reused, resulting in a reduction of 55% of the specification size. Inclusion, parametrization and sub-specification have facilitated modularity and internal reuse of UI specifications at development time, whereas the reuse of UI elements between applications has greatly benefited from sharing repositories of UI elements at run time.Ministerio de Ciencia e Innovación DPI2010-19154Junta de Andalucía TIC-633

    Comparison between two-fluid model simulations and particle image analysis & velocimetry (PIV) results for a two-dimensional gas-solid fluidized bed

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    This work compares simulation and experimental results of the hydrodynamics of a two-dimensional, bubbling air-fluidized bed. The simulation in this study has been conducted using an Eulerian–Eulerian two-fluid approach based on two different and well-known closure models for the gas–particle interaction: the drag models due to Gidaspow and Syamlal & O'Brien. The experimental results have been obtained by means of Digital Image Analysis (DIA) and Particle Image Velocimetry (PIV) techniques applied on a real bubbling fluidized bed of 0.005 m thickness to ensure its two-dimensional behaviour. Several results have been obtained in this work from both simulation and experiments and mutually compared. Previous studies in literature devoted to the comparison between two-fluid models and experiments are usually focused on bubble behaviour (i.e. bubble velocity and diameter) and dense-phase distribution. However, the present work examines and compares not only the bubble hydrodynamics and dense-phase probability within the bed, but also the time-averaged vertical and horizontal component of the dense-phase velocity, the air throughflow and the instantaneous interaction between bubbles and dense-phase. Besides, quantitative comparison of the time-averaged dense-phase probability as well as the velocity profiles at various distances from the distributor has been undertaken in this study by means of the definition of a discrepancy factor, which accounts for the quadratic difference between simulation and experiments The resulting comparison shows and acceptable resemblance between simulation and experiments for dense-phase probability, and good agreement for bubble diameter and velocity in two-dimensional beds, which is in harmony with other previous studies. However, regarding the time-averaged velocity of the dense-phase, the present study clearly reveals that simulation and experiments only agree qualitatively in the two-dimensional bed tested, the vertical component of the simulated dense-phase velocity being nearly an order of magnitude larger than the one obtained from the PIV experiments. This discrepancy increases with the height above the distributor of the two-dimensional bed, and it is even larger for the horizontal component of the time-averaged dense-phase velocity. In other words, the results presented in this work indicate that the fine agreement commonly encountered between simulated and real beds on bubble hydrodynamics is not a sufficient condition to ensure that the dense-phase velocity obtained with two-fluid models is similar to that from experimental measurements on two-dimensional bedsThis work has been partially funded by the Spanish Government (ProjectDPI2009-10518) and the Autonomous Community of Madrid (ProjectS2009/ENE-1660). Their supports are greatly appreciatedPublicad

    Study of the transformation of boehmite into alumina by Rietveld method

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    XXII Congress and General Assembly International Union of Crystallography. IUCr2011. Madrid, 22-30 Agosto, 2011. A publicar en Acta Cryst. (2011) A67, C580The aim of this paper is to study the conversion of boehmite into alumina, by means of the application of Rietveld refinement methodPeer reviewe

    BIM Methodology Applied to Architectural Heritage Preservation: Case Study of the Medina and Dungeons of Tetuán, Morocco

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    The aim of the proposed contribution is to investigate how the application of BIM methodology in the field of the architectural heritage can avail both the study of an historical building and its subsequent preservation. Starting from the analysis carried out in the Medina and Dungeons of Tetuán (Morocco), we propose a H-BIM (Historic Building Information Modelling) methodology focused on the pathological parametric study of the buildings (as-damaged model) and therefore obtain a specific information database for each architectural element. The goal of the work is to establish a digital parametric methodology that is both inherent to the pathological and geometric study of a vivienda of the Medina as well as applicable to diverse cases within that realm, starting with a hybrid traditional (CAD) and innovative (photogrammetry) database combined. Furthermore, the hybrid workflow allows to rise above the limitations that the (geographical) distance often presents from case studies and it allows overcoming the common difficulties encountered in a traditional restoration-conservative study in finding information. The choice of this particular case study enables evaluating the updatability of an H-BIM model and therefore the possibility of containing different information dating back to different phases of survey and project that can be parameterized and compared, with the aim of ensuring both the historical traceability of the degradation of the asset and its architectural composition over time. Lastly, an H-BIM catalogue of the different viviendas which were analysed in the preliminary phase is proposed, starting from a typical house in the Medina of Tetuán, so as to initiate a realistic data collection of the Medina of Tetuán with the aim of undertaking a preventive restoration without having to resort to interventions of emergency and structural reinforcement as foreseen in the case of the Ben Marzouk house and the dungeons (mazmorras)
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