Aerodynamic Optimization of High-Speed Trains Nose using a Genetic Algorithm and Artificial Neural Network

An aerodynamic optimization of the train aerodynamic characteristics in term of front wind action sensitivity is carried out in this paper. In particular, a genetic algorithm (GA) is used to perform a shape optimization study of a high-speed train nose. The nose is parametrically defined via Bézier Curves, including a wider range of geometries in the design space as possible optimal solutions. Using a GA, the main disadvantage to deal with is the large number of evaluations need before finding such optimal. Here it is proposed the use of metamodels to replace Navier-Stokes solver. Among all the posibilities, Rsponse Surface Models and Artificial Neural Networks (ANN) are considered. Best results of prediction and generalization are obtained with ANN and those are applied in GA code. The paper shows the feasibility of using GA in combination with ANN for this problem, and solutions achieved are included

Optimal security-constrained power scheduling by Benders decomposition

This paper presents a Benders decomposition approach to determine the optimal day-ahead power scheduling in a pool-organized power system, taking into account dispatch, network and security constraints. The study model considers the daily market and the technical constraints resolution as two different and consecutive processes. The daily market is solved in a first stage subject to economical criteria exclusively and then, the constraints solution algorithm is applied to this initial dispatch through the redispatching method. The Benders partitioning algorithm is applied to this constraints solution process to obtain an optimal secure power scheduling. The constraints solution includes a full AC network and security model to incorporate voltages magnitudes as they are a critical factor in some real power systems. The algorithm determines the active power committed to each generator so as to minimize the energy redispatch cost subject to dispatch, network and security constraints. The solution also provides the reactive power output of the generators, the value of the transformers taps and the committed voltage control devices. The model has been tested in the IEEE 24-bus Reliability Test System and in an adapted IEEE 118-bus Test System. It is programmed in GAMS mathematical modeling language. Some relevant results are reported.Publicad

Cambio cultural y desarrollo humano en contextos minoritarios : el papel de la mujer en una comunidad gitana /

Consultable des del TDXTítol obtingut de la portada digitalitzadaEsta tesis es un estudio, desde el marco epistemológico de la Psicología Cultural, de los procesos de cambio cultural en una comunidad minoritaria. Parte de los datos recogidos en un proyecto de investigación - acción participante, de datos etnográficos y de entrevistas grupales. Adopta un enfoque evolutivo al afrontar el estudio de los procesos de socialización y de formación de la identidad en el marco las comunidades gitanas, orientándose a partir de los postulados teóricos y los trabajos prácticos de autores como Vygotsky, Bruner, Rogoff, Cole , Greenfield y Valsiner. Se aborda, desde un enfoque psicosocial, el estudio de los procesos de identidad minoritaria, de relaciones interculturales y de relaciones de poder, todo ello desde una perspectiva situada. Las conclusiones del estudio son las siguientes: 1. Existe actualmente un marcado proceso de cambio cultural en las sociedades gitanas. 2. Este proceso de cambio no puede desligarse de la condición de minorías culturales de las sociedades gitanas. 3. Esta nueva organización de roles supone cambios importantes en el proyecto de desarrollo de los miembros de esta cultura. 4. Este cambio, entre otras cosas, supone una nueva organización de los roles de género. 5. La nueva orientación del desarrollo de los sujetos en la cultura gitana (grupo minoritario) no puede asimilarse a la orientación del desarrollo de los sujetos del grupo dominante. 6. Los cambios en las estrategias educativas dan lugar a nuevos sujetos que contribuyen al cambio cultural.This work is an study, from Cultural Psychology epistemological frame, about cultural change processes in a minority community. Data are collected from a research-intervention project, ethnographical data and group interview. The study adopt a developmental focus in the analysis of socialisation processes and identity construction inside gypsy communities, oriented by theoretical frame developed by authors as Vygotsky, Bruner, Rogoff, Cole , Greenfield y Valsiner. A psychosocial focus is analysis of minority self, intercultural relationships and power relationships, from a situated perspective. These are the conclusions: : 7. Exists today a deep process of cultural change in gypsy societies. 8. For understand this process must be link with the condition of cultural minorities of these societies. 9. Cultural change suppose new role distribution and, consequently, important changes in the «developmental project» of memberships of culture. 10. There are a new organisation of gender roles. 11. New developmental orientation cannot be assimilated to development of members of dominant culture. 12. Changes in educational strategies produce new subjects that contribute to cultural change

Exploring Document Clustering Techniques for Personalized Peer Assessment in Exploratory Courses

Proceedings of: Computer-Supported Peer Review in Education: Synergies with Intelligent Tutoring Systems (CSPRED 2010), Pittsburgh, Pennsylvania USA, June 14th, 2010.Peer review has been proposed as a complement to project-based learning in courses covering a wide and heterogeneous syllabus. By reviewing peers' projects, students can explore other subjects thoroughly apart from their own project topic. This objective relies however in a proper distribution of the works to review, which is a complex and time-consuming task. Beyond simple topic selection, students may report different types of works, which influence their peers' assessment; for example, works focused on a project development approach versus in-depth literature researches. Introducing detailed metadata is time-consuming (thus users are typically reluctant) and, even more important, prone to error. In this paper we explore the potential of text mining and natural language processing technologies for automatic classification of texts, in order to facilitate the adaptation and diversification of the works assigned to the students for review, in the context of a course on Artificial Intelligence.This work was partially funded by Best Practice Network ICOPER (Grant No. ECP-2007-EDU-417007), Learn3 project, “Plan Nacional de I+D+I” TIN2008-05163/TSI, and eMadrid network, S2009/TIC-1650, “Investigación y Desarrollo de tecnologías para el e-learning en la Comunidad de Madrid”.Publicad

Combined hydro-wind generation bids in a pool-based electricity market

Present regulatory trends are promoting the irect participation of wind energy in electricity markets. The final result of these markets sets the production scheduling for the operation time, including a power commitment from the wind generators. However, wind resources are uncertain, and the final power delivered usually differs from the initial power committed. This imbalance produces an overcost in the system, which must be paid by those who produce it, e.g., wind generators among others. As a result, wind farm revenue decreases, but it could increase by allowing wind farms to submit their bids to the markets together with a hydro generating unit, which may easily modify its production according to the expected imbalance. This paper presents a stochastic optimization technique that maximizes the joint profit of hydro and wind generators in a pool-based electricity market, taking into account the uncertainty of wind power prediction.En prens

Real picture films of advertising cinema screened in Spain between 1957 and 1967

Esta aportación pretende contribuir a la caracterización formal de lo que desde el ámbito académico se ha dado en llamar cine publicitario. Ante la imposibilidad de una empresa totalizadora a este respecto se ha optado por el examen de una muestra espacial, temporal y formalmente acotada, en concreto el análisis de 29 spots cinematográficos de imagen real exhibidos en España entre 1957 y 1967. La selección de este corpus, geográficamente ligado al entorno del investigador, se ha fundamentado en la preponderancia e importancia de la técnica de realización en la producción publicitaria y audiovisual posterior; en las decisivas transformaciones sociales, mediáticas, publicitarias e industriales acaecidas en el periodo: el asentamiento del capitalismo de consumo, la estructuración del medio cine, la modernización de la actividad publicitaria o el surgimiento de la televisión; y en la mayor representatividad de las piezas en una etapa de monopolio sectorial nacional. La articulación del contexto de interpretación se ha edificado sobre el vaciado y contraste de fuentes. El examen del contenido muestral se ha sustentado, por su parte, sobre los procedimientos habituales en el análisis del filme no olvidando en cualquier caso las particularidades industriales, funcionales, discursivas y expresivas de la disciplina publicitaria.This paper aims to contribute to the formal characterization of what from the academic field has been called advertising cinema. Given the impossibility of a totalizing enterprise in this regard, we have chosen a spatial, temporal and formally bounded sample, specifically, the analysis of 29 real picture films of advertising cinema screened in Spain between 1957 and 1967. The selection of this corpus, geographically linked to the researcher environment, has been based, on the one hand, on the prevalence and importance of the technique in later audiovisual and advertising production; on the other hand, on the social, media, advertising and industrial mutations that took place on those years: the settlement of consumer capitalism, the emergence of cinema as an advertising media, the modernization of advertising and the arrival of television; finally, on the larger representational possibilities of the films in a national and sectorial monopoly. The research study has been based on the use of authoritative sources and film analysis, not forgetting, anyway, the distinctive features of advertising

Detectors could spot plagiarism in research proposals

Having all been involved in proposal evaluation, we believe the studies indicate that a text matching analysis of research proposals could reduce plagiarism in subsequent publications. For instance, when European Commission evaluators have met in the past to evaluate research proposals, they received printed copies which had to be returned before the panel members left, and had no computer access during deliberations. A plagiarism detector using text-mining methods could be used instead of the current security measures. Such a system could, in principle, detect similarities to previous submissions and uncited sources using advanced document segmentation. Only official agencies have access to confidential proposals and the funds to experiment with automated plagiarism-detectors. It is important that they should investigate these approaches to reducing the possibility of scientific misconduct

Digitalization of film image and the lack of technological standards

Este artículo aborda la digitalización de los procesos productivos cinematográficos para analizar uno de sus principales retos, el establecimiento de estándares digitales para le tratamiento de la imagen. Con ello se establece una relación entre tecnología digital y la evolución del cine como actividad empresarial en un entorno altamente competitivo.The purpose of this study is to analyze the digitalization of film production processes focusing on one of its major problems, the establishment of digital standards on the realm of image manipulation. This paper aims at relating digital technology and the development of cinema as a business activity in a highly competitive enviroment

Alta fidelidad. El uso inmaduro de las imágenes digitales en la arquitectura

[EN] As regards architectural digital design, computer rendered images seem to be the least accomplished and most controversial feature whereas other graphic tools have successfully developed in the realms of architectural creation and production.The wish for authenticity associated with this kind of rendering can trigger a number of malfunctions The search for role models, the fast obsolescence prompted by the consumer’s increasingly trained perception, the loss aversion factor, the unrealistic innovation expectations, and the exclusivity originated by technical complexity, in the pursuit of achieving status or concealing faulty approaches, can be counted among the factors that can help us to understand and foresee the limitations in front of us.[ES] Las imágenes generadas por ordenador (render), parecen ser el aspecto peor logrado, menos acertado y más controvertido del dibujo arquitectónico digital, mientras que otras herramientas gráficas digitales han conseguido un desarrollo satisfactorio y específico en la producción e ideación arquitectónicas. La pretensión de verosimilitud (realismo) de este tipo de visualización puede ser el desencadenante de otras muchas disfunciones. La búsqueda de referentes propios, su carácter meramente comercial como producto final, la rápida obsolescencia producida por la percepción cada vez más educada del receptor, el factor nostálgico de pérdida, el falso aporte producido por unas desvanecidas expectativas de originalidad e innovación, la exclusividad generada por las complejidades técnicas utilizadas para obtener un estatus o enmascarar planteamientos débiles, son algunos de los factores que nos pueden ayudar a comprender y pronosticar las limitaciones con que nos encontramos.García Crespo, JM. (2021). High fidelity. The immature use of digital images for architecture. EGA Expresión Gráfica Arquitectónica. 26(42):156-167. https://doi.org/10.4995/ega.2021.14628OJS156167264

Aerodynamic Optimization of a High-speed Train using Genetic Algorithms

Genetic algorithms (GA) have been used for the minimization of the aerodynamic drag of a train subject to front wind. The significant importance of the external aerodynamic drag on the total resistance a train experiments as the cruise speed is increased highlights the interest of this study. A complete description of the methodology required for this optimization method is introduced here, where the parameterization of the geometry to be optimized and the metamodel used to speed up the optimization process are detailed. A reduction of about a 25% of the initial aerodynamic drag is obtained in this study, what confirms GA as a proper method for this optimization problem. The evolution of the nose shape is consistent with the literature. The advantage of using metamodels is stressed thanks to the information of the whole design space extracted from it. The influence of each design variable on the objective function is analyzed by means of an ANOVA test