The role of motivation in the learning of English as a foreign language

This study investigates the role of motivation in foreign language learning and the factors that might affect learners' motivation. 137 secondary school students took part in the study. Correlations between the students' English proficiency and motivation were performed. Questionnaires on the ideal English teacher and the students' actual English teachers were also delivered. The purpose of correlating the ideal English teacher with the students' real English teachers was to investigate if this factor might affect student's motivation and consequen tly students' English proficiency. The results indicated that teachers affect students' motivation and that there exist significant correlations between motivation and foreign language learning

The role of motivation in the learning of English as a foreign language

[spa] La principal hipótesis que se plantea en esta tesis es que la motivación influye en el aprendizaje del inglés como lengua extranjera. Otra de las hipótesis planteadas es que el entorno socio-cultural y/o el profesor pueden influir notablemente en la motivación del alumno y, por tanto, en su aprendizaje del inglés como lengua extranjera. El estudio estadístico de datos relativos al aprendizaje del inglés, a la motivación y al entorno socio-cultural de 137 estudiantes que fueron encuestados cuando cursaban Primero y Tercero de BUP, junto con datos de personalidad y formas de enseñar de sus profesores, han validado las hipótesis mencionadas, ya que las correlaciones de estos datos han resultado significativas

Column-generation and interior point methods applied to the long-term electric power-planning problem

Aquesta tesi s'adreça al problema de planificació de la generació elèctrica a llarg termini per a una companyia específica (SGC) que participa en un mercat liberalitzat organitzat en un pool. Els objectius de la tesi són: modelitzar aquest problema, i desenvolupar i implementar tècniques apropiades i eficients que el resolguin. Un planificació òptima a llarg termini és important, per exemple, per a la confecció de pressupostos, o per a la gestió de compres/consum de combustibles. Una altra aplicació és la de guiar la planificació a curt termini perquè aquesta tingui en compte decisions preses sota una òptica de llarg termini. La nostra proposta per a fer la planificació de la generació és optimitzar la generació esperada de cada unitat (o la unió de diverses unitats de característiques semblants) del pool per a cada interval en que dividim el llarg termini. El model bàsic per la planificació de la generació a llarg termini (LTGP) maximitza el benefici de totes les unitats del pool. La constricció més important és la satisfacció de la demanda, ja que el sistema està sempre balancejat. Utilitzem la formulació de Bloom i Gallant, la qual modela la càrrega a través d'una monòtona de càrrega per cada interval i requereix un número exponencial de constriccions lineals de desigualtat, anomenades LMCs. Altres constriccions (lineals) incloses en el model són: garantia de potència, límits en la disponibilitat de combustibles, emissions màximes de CO2 o una quota de mercat mínima per a la SGC. Una extensió d'aquest model és la planificació conjunta de l'assignació de manteniments de les unitats tèrmiques d'una SGC amb la planificació de la generació. El model conjunt és un problema quadràtic amb variables binàries i contínues. Per resoldre aquest model es proposa un parell d'heurístiques i s'ha implementat un prototipus de branch and bound en AMPL.Aquesta tesi també proposa una manera per coordinar el model LTGP proposat amb una planificació a curt termini. Es desenvolupa un model de curt que inclou els resultats de llarg termini. Donat que el model de planificació a llarg termini s'ha de resoldre sovint (principalment per passar informació acurada al model de curt), les tècniques emprades per a resoldre'l han de donar resultats fiables en un espai de temps curt. Les tècniques aplicades han estat:· Donat que les constriccions de recobriment i les fites de no negativitat defineixen un políedre convex els vèrtexs del qual són fàcils de trobar el model es transforma i les variables esdevenen els coeficients convexos que defineixen un punt. Aquest nou problema es resolt amb l'algoritme de Murtagh i Saunders, que és un procediment òptim. Aquest algoritme s'aplica sota un esquema de generació de columnes donat que el número de vèrtexs del políedre és comparable al número de constriccions. L'avantatge d'aquest mètode és que els vèrtexs es van generant a mesura que es necessiten.· L'aplicació de mètodes directes és computacionalment costós donat el número exponencial de LMCs. De totes maneres, a l'òptim només un conjunt reduït de constriccions de recobriment seran actives. Hem desenvolupat una heurística, anomenada heurística GP, la qual genera un subconjunt de constriccions, entre les quals hi ha les LMCs que són actives a l'òptim. L'heurística resol una seqüència de problemes quadràtics, els quals incrementen el número de LMCs considerades a cada iteració. Els problemes es resolen amb mètodes de punt interior que s'inicialitzen amb tècniques de warm start per tal d'accelerar la convergència cap a la nova solució. Aquest procediment resulta ser molt més eficient que el de generació de columnes. La modelització i els casos de prova estan basats en dades d'un sistema de pool pur i de mercat com ha estat a Espanya fins el juliol de 2006.This thesis presents an approach to the long-term planning of power generation for a company (SGC) participating in a liberalized market organized as a pool. The goal of this thesis is two-fold: to model the problem and to develop and implement appropriate and efficient techniques for solving it.The optimization of the long-term generation planning is important for budgeting and planning fuel acquisitions, and to give a frame where to fit short-term generation planning.Our proposal for planning long-term generation is to optimize the expected generation of each unit (or the merger of several units of the same type) in the power pool over each interval into which the long-term horizon is split.The basic model for long-term generation planning (LTGP) maximizes the profit for all the units participating in the pool. The most important constraint is matching demand, since the market always clears. The Bloom and Gallant formulation is used, which models the load with a load-duration curve for each interval and requires an exponential number of linear inequality constraints, called herein LMCs. Other (linear) constraints included in the model are: minimum generation time, limits on the availability of fuel, maximum CO2 emission limits or the market share of the SGC. This thesis also proposes the way in which coordination between the LTGP model developed and a short-term plan should be considered and provides a model for short-term electrical power planning adapted to the LTGP proposed and which includes the long-term results.Another decision that needs to be taken from a long-term point of view is the joint scheduling of thermal unit maintenances with the generation planning of a particular SGC. The results of a prototype of a Branch and Bound implemented in AMPL are included in this thesis.Long-term planning needs to be considered before short-term planning and whenever the real situation deviates from the forecasted parameters, so the techniques implemented must be efficient so as to provide reliable solutions in a short time. Two methods for handling the LMCs are proposed and compared:● A decomposition technique exploits the fact that the LMCs plus the non-negativity bounds define a convex polyhedron for each interval whose vertices are easy to find. Thus, the problem is transformed and the variables become the coefficients of a convex combination of the vertices. The transformed problem is quadratic with linear constraints, making it suitable to be solved with the Murtagh & Saunders algorithm, which gives an optimal solution. A column-generation approach is used because the number of vertices of the polyhedron is comparable to the number of LMCs. The advantage of this method is that it does not require previous computation of all of the vertices, but rather computes them as the algorithm iterates.● The application of direct methods is computationally difficult because of the exponential number of inequality LMCs. However, only a reduced subset of LMCs will be active at the optimizer. A heuristic, named GP heuristic, has been devised which is able to find a reduced set of LMCs including those that are active at the optimizer. It solves a sequence of quadratic problems in which the set of LMCs considered is enlarged at each iteration. The quadratic problems are solved with an interior point method, and warm starts are employed to accelerate the solution of the successively enlarged quadratic problems. This procedure is more efficient than the column generation one.The modeling and tests of this thesis are based on the pure pool system and market data from the Spanish system up to July 2006

Economic evaluation of the water reutilization for the creation of artificial wetlands

Orígenes y tratamiento de las aguas residuales. Funcionamiento de las estaciones depuradoras de aguas residuales (EDAR'S) y de los sistemas de humedales construidos (SHC'S). Evaluación económica de los (PMV) SHC --> Ejemplo: Can Cabanyes. Precio mínimo de venta del agua regenerada en los SHC y beneficios generados por los SHC. Ingresos generados por los SHC y factores limitantes del PMV y del agua regenerada

Fiber-Optic Communications

Transparències de l'assignatura "Comunicacions Òptiques" del curs 4B d'enginyeria de telecomunicacions.2010/201

Study of the effect of lignin to a nanocellulose film

Cellulose is the most common material in nature, that is mostly used in the production of paper. Studies with this product have developed a series of sub products that have interesting properties in a variety of applications. One of these materials, obtained by chemical or mechanical processes is crystalline nanocellulose, or CNC. CNC, since it is a derivative of cellulose, holds most of its organic properties, but also allows a lot of flexibility in how it is processed. If it is disposed in thin layers and left to dry out for a period of time, it generates a thin film. This material resembles a plastic film, with the added factor of being slightly iridescent to light. Since this product has very similar properties to cellulose, adding a variety of other materials could affect its properties and allow for the creation of a film alternative. The greatest advantage of using such a product is the fact that it decomposes rapidly and doesn’t use petroleum in its production. Lignin is another sub product of the paper production industry, since this material gives paper a yellow shade that is usually not desired. Paper production plants use the lignin extracted in the pulping process to generate power by burning it down, but this material holds a very interesting property for making a film substitute. By mixing nanocellulose and lignin, it is possible to generate a film with different properties. This study intends to analyze these properties and evaluate if they could allow for this product to be an alternative to petroleum-based films. Other additives, besides lignin will also be used to allow for better sample testing, properties, or simply to allow lignin to fully dissolve in CNC. Studies in this subject, and specifically in the use of CNC have been a growing trend in an attempt to reduce the manufacturing of petroleum-based materials. Throughout this study, physical, barrier and optical properties will be evaluated in relation to the concentration of lignin and other additives used in the production of films

A universal specification for multicore fiber crosstalk

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In order to transition multi-core fiber (MCF) technologies from their research state to volume production, the key design specifications have to be broadly agreed upon, first and foremost an acceptable level of inter-core crosstalk per unit length. Against common belief, we show that MCF crosstalk requirements per unit length are fairly independent of transmission distance in the context of modern coherent optical communication systems. As a consequence, a single value for the tolerable inter-core crosstalk per unit length can be used to specify MCFs, valid from metropolitan (~100 km) to trans-pacific (~10 000 km) deployment scenarios. The notion of a universal inter-core crosstalk specification allows for application-independent MCF designs (including a distance-independent optimum core density) and will facilitate the standardization and volume manufacturing of MCF.Peer ReviewedPostprint (author's final draft