Aplicació en línia d'un sistema variable de control multivariable en un Reactor ..

L’objecte del present treball és la realització d’una aplicació que permeti portar a terme el control estadístic multivariable en línia d’una planta SBR.Aquesta eina ha de permetre realitzar un anàlisi estadístic multivariable complet del lot en procés, de l’últim lot finalitzat i de la resta de lots processats a la planta.L’aplicació s’ha de realitzar en l’entorn LabVIEW. L’elecció d’aquest programa vecondicionada per l’actualització del mòdul de monitorització de la planta que s’estàdesenvolupant en aquest mateix entorn

Modeling and control of electromechanical systems

The material presented in the these notes covers the sessions Modelling of electromechanical systems, Passive control theory I and Passive control theory II of the II EURON/GEOPLEX Summer School on Modelling and Control of Complex Dynamical Systems.We start with a general description of what an electromechanical system is from a network modelling point of view. Next, a general formulation in terms of PHDS is introduced, and some of the previous electromechanical systems are rewritten in this formalism. Power converters, which are variable structure systems (VSS), can also be given a PHDS form.We conclude the modelling part of these lectures with a rather complex example, showing the interconnection of subsystems from several domains, namely an arrangement to temporally store the surplus energy in a section of a metropolitan transportation system based on dc motor vehicles, using either arrays of supercapacitors or an electric poweredflywheel. The second part of the lectures addresses control of PHD systems. We first present the idea of control as power connection of a plant and a controller. Next we discuss how to circumvent this obstacle and present the basic ideas of Interconnection and Damping Assignment (IDA) passivity-based control of PHD systems.

Hybrid model of a double-fed induction machine and back-to-back converter

This report details the port interconnection of two subsystems: a power electronics subsystem (a back-to-back AC/AC converter (B2B), coupled to a phase of the power grid), and an electromechanical subsystem (a doubly-fed induction machine (DFIM), coupled mechanically to a flywheel and electrically to the power grid and to a local varying load). Both subsystems have been essentially described in previous reports (deliverables D 0.5 and D 4.3.1), although some previously unpublished details are presented here. The B2B is a variable structure system (VSS), due to the presence of control-actuated switches: however from a modelling and simulation, as well as a control-design, point of view, it is sensible to consider modulated transformers (MTF in the bond-graph language) instead of the pairs of complementary switches. The port-Hamiltonian models of both subsystems are presents and coupled through a power-preserving interconnection, and the Hamiltonian description of the whole system is obtained; detailed bond-graphs of all the subsystems and the complete system are provided.

Energy-based modelling and simulation of the interconnection of a back-to-back converter and a doubly-fed induction machine

This paper describes the port interconnection of two subsystems: a power electronics subsystem (a back-to-back AC/CA converter (B2B), coupled to a phase of the power grid), and an electromechanical subsystem (a doubly-fed induction machine (DFIM). The B2B is a variable structure system (VSS), due to presence of control-actuated switches: however, from a modelling simulation, as well as a control-design, point of view, it is sensible to consider modulated transformers (MTF in the bond graph language) instead of the pairs of complementary switches. The port-Hamiltonian models of both subsystems are presented and, using a power-preserving interconnection, the Hamiltonian description of the whole system is obtained; detailed bond graphs of all subsystems and the complete system are also provided. Using passivity-based controllers computed in the Hamiltonian formalism for both subsystems, the whole model is simulated; simulations are run to rest the correctness and efficiency of the Hamiltonian network modelling approach used in this work.

La segregació i l'escat de guerres civils

Tradicionalment, s’ha considerat que les característiques ètniques d’un país són un factor rellevant per a l’esclat d’una guerra civil. Han estat objecte d’una anàlisi extensa mitjançant índexs de fraccionament ètnic (quants grups diferents hi ha) i de polarització ètnica (el nombre i la mida relativa dels grups), però sense resultats concloents. Un aspecte que interiorment s’havia passat per alt és la distribució física dels grups dins d’un país. Aquest article selecciona un índex de segregació i s’analitza la relació amb l’esclat de guerres civils a través de tres bases de dades consolidades, dues de les quals amb un llindar alt de víctimes mortals i una altra amb un llindar baix. Aquesta recerca revela que l’índex de segregació és significatiu per predir l’inici d’una guerra civil. Tot i que la segregació forçosament ha de dependre del fraccionament i que probablement és condicionada per la polarització, l’anàlisi mostra que, un cop s’introdueix la segregació com a variable de control, el fraccionament i la polarització deixen de ser significatius a l’hora de calcular les probabilitats de conflicte civil a través de les bases de dades de llindar alt. L’article sosté que els efectes de la segregació es desenvolupen a través de la separació física respecte d’altres grups ètnics, la proximitat física dins d’un mateix grup i l’homogeneïtat en el si d’un territori, i que cada un d’aquests factors influeix tant sobre la motivació per rebel·lar-se com sobre la viabilitat de la rebel·lió. La significativitat de la segregació mostra que l’impacte de les característiques ètniques sobre el conflicte és complex i que el concepte de segregació aporta una dimensió útil a l’especificació de l’etnicitat.

The illusion of control, the structures of prizes and the demand for football pools in Spain

Using data for all the fixtures for the seasons from 1972-73 to 2002-03, we estimate a dynamic model of demand for football pools in Spain paying attention to whether their main economic explanatory variable is the effective price of a ticket or the jackpot. Additionally, we evaluate the importance of the composition of the list of games in terms of whether First Division matches are included or not. Results show that the jackpot model is preferred to the effective price model, having important implications in terms of how the structure of the game should be changed in order to increase demand.

Urban spatial structure and suburbanisation. The case of the Barcelona Metropolitan

The metropolitan spatial structure displays various patterns, sometimes monocentricity and sometimes multicentricity, which seems much more complicated than the exponential density function used in classic works such as Clark (1961), Muth (1969) or Mills (1973) among others, can effectively represent. It seems that a more flexible density function,such as cubic spline function (Anderson (1982), Zheng (1991), etc.) to describe the density-accessibility relationship is needed. Also, accessibility, the fundamental determinant of density variations, is only partly captured by the inclusion of distance to the city centre as an explanatory variable. Steen (1986) has proposed to correct that miss-especification by including an additional gradient for distance to the nearest transportation axis. In identifying the determinants of urban spatial structure in the context of inter-urban systems, some of the variables proposed by Muth (1969), Mills (1973) and Alperovich (1983) such as city age or population, make no sense in the case of a single urban system. All three criticism to the exponential density function and its determinants apply for the Barcelona Metropolitan Region, a polycentric conurbation structured on well defined transportation axes.

Patrones de tomate: resistencia variable frente al nematodo Meloidogyne

Los patrones de tomate se han propuesto como una alternativa no química al uso del bromuro de metilo. En este estudio se evaluó la respuesta de resistencia de diez patrones de tomate (comerciales y experimentales) a nematodos del género Meloidogyne mediante un ensayo de campo realizado en un invernadero de plástico cuyo suelo se hallaba infestado por Meloidogyne javanica. Al finalizar la campaña agrícola (marzo a julio), siete de los patrones ensayados mostraron altos niveles de resistencia, uno presentó resistencia intermedia y dos resultaron ser susceptibles al nematodo.

Technology, business models and network structure in the airline industry

Network airlines have been increasingly focusing their operations on hub airports through the exploitation of connecting traffic, allowing them to take advantage of economies of traffic density, which are unequivocal in the airline industry. Less attention has been devoted to airlines? decisions on point-to-point thin routes, which could be served using different aircraft technologies and different business models. This paper examines, both theoretically and empirically, the impact on airlines ?networks of the two major innovations in the airline industry in the last two decades: the regional jet technology and the low-cost business model. We show that, under certain circumstances, direct services on point-to-point thin routes can be viable and thus airlines may be interested in deviating passengers out of the hub.

Technology, business models and network structure in the airline industry

Network airlines have been increasingly focusing their operations on hub airports through the exploitation of connecting traffic, allowing them to take advantage of economies of traffic density, which are unequivocal in the airline industry. Less attention has been devoted to airlines' decisions on point-to-point thin routes, which could be served using different aircraft technologies and different business models. This paper examines, both theoretically and empirically, the impact on airlines' networks of the two major innovations in the airline industry in the last two decades: the regional jet technology and the low-cost business model. We show that, under certain circumstances, direct services on point-to-point thin routes can be viable and thus airlines may be interested in deviating passengers out of the hub. Keywords: regional jet technology; low-cost business model; point-to-point network; hub-and-spoke network JEL Classi…fication Numbers: L13; L2; L93

Population genetic structure and demography analysis in palinurus elephas populations from atlantic and mediterranean waters

Report for the scientific sojourn at the University of Reading, United Kingdom, from January until May 2008. The main objectives have been firstly to infer population structure and parameters in demographic models using a total of 13 microsatellite loci for genotyping approximately 30 individuals per population in 10 Palinurus elephas populations both from Mediterranean and Atlantic waters. Secondly, developing statistical methods to identify discrepant loci, possibly under selection and implement those methods using the R software environment. It is important to consider that the calculation of the probability distribution of the demographic and mutational parameters for a full genetic data set is numerically difficult for complex demographic history (Stephens 2003). The Approximate Bayesian Computation (ABC), based on summary statistics to infer posterior distributions of variable parameters without explicit likelihood calculations, can surmount this difficulty. This would allow to gather information on different demographic prior values (i.e. effective population sizes, migration rate, microsatellite mutation rate, mutational processes) and assay the sensitivity of inferences to demographic priors by assuming different priors.

Disseny i implementació d'un sistema de control de projectes

Aquest treball de fi de carrera, com descriu el seu títol, consisteix a dissenyar i implementar un sistema de control de projectes. Com tot projecte, complirà el requisit de disposar d'un pla que permeti fer un seguiment dels terminis d'execució, de les fites establertes i un control dels lliurables identificats. Pel fet de tractar-se del desenvolupament d'un sistema informàtic, considerarà les etapes d'especificació de requisits, anàlisi, disseny, codificació, proves unitàries i proves funcionals, i es generaran els informes pertinents que serveixin de documentació i de referència en les etapes posteriors. Des d'un punt de vista tecnològic, permetrà aprofundir en el coneixement de l'estructura de funcionament del PL/SQL d'Oracle (crides a procediments i, especialment, al tractament).

Diseño e Implementación de un Sistema de Control de Proyectos

Aquest treball de final de carrera té com a objectiu fer el disseny i la implementació d'un sistema de control de projectes per a una organització, de manera que la seva estructura interna i funcionament segueixin els paràmetres especificats a l'enunciat proporcionat per la consultora de l'assignatura. El sistema ha de recollir informació sobre quan de temps i en què treballa cada treballador, i quines han estat les despeses mentre ha estat assignat a cada projecte o tasca. D'aquesta manera, a més de tenir un control horari del treballador, l'organització sabrà perfectament si la realització d'un projecte ha estat rendible i disposarà, durant el desenvolupament, de dades sobre l'evolució de costos i hores per a executar les actuacions correctives pertinents.

Disseny i implementació d'un sistema de control de projectes

L'objectiu d'aquest treball és fer el disseny i la implementació d'un sistema de control de projectes per a una organització X, de manera que la seva estructura i funcionament compleixin uns requisits inicials.

Identification and Semiactive Control of Smart Structures Equipped with Magnetorheological Actuators

This paper deals with the problem of identification and semiactive control of smart structures subject to unknown external disturbances such as earthquake, wind, etc. The experimental setup used is a 6-story test structure equipped with shear-mode semiactive magnetorheological actuators being installed in WUSCEEL. The experimental results obtained have verified the effectiveness of the proposed control algorithms