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.

Passive modernization? the new human development index and its components in Italy’s regions (1871-2007)

The article presents and discusses estimates of social and economic indicators for Italy’s regions in benchmark years roughly from Unification to the present day: life expectancy, education, GDP per capita at purchasing power parity, and the new Human Development Index (HDI). A broad interpretative hypothesis, based on the distinction between passive and active modernization, is proposed to account for the evolution of regional imbalances over the long-run. In the lack of active modernization, Southern Italy converged thanks to passive modernization, i.e., State intervention: however, this was more effective in life expectancy, less successful in education, expensive and as a whole ineffective in GDP. As a consequence, convergence in the HDI occurred from the late XIX century to the 1970s, but came to a sudden halt in the last decades of the XX century.

Passive smoking in babies: The BIBE Study (Brief Intervention in babies. Effectiveness)

Background: There is evidence that exposure to passive smoking in general, and in babies in particular, is an important cause of morbimortality. Passive smoking is related to an increased risk of pediatric diseases such as sudden death syndrome, acute respiratory diseases, worsening of asthma, acute-chronic middle ear disease and slowing of lung growth.The objective of this article is to describe the BIBE study protocol. The BIBE study aims to determine the effectiveness of a brief intervention within the context of Primary Care, directed to mothers and fathers that smoke, in order to reduce the exposure of babies to passive smoking (ETS).Methods/DesignCluster randomized field trial (control and intervention group), multicentric and open. Subject: Fathers and/or mothers who are smokers and their babies (under 18 months) that attend pediatric services in Primary Care in Catalonia.The measurements will be taken at three points in time, in each of the fathers and/or mothers who respond to a questionnaire regarding their baby's clinical background and characteristics of the baby's exposure, together with variables related to the parents' tobacco consumption. A hair sample of the baby will be taken at the beginning of the study and at six months after the initial visit (biological determination of nicotine). The intervention group will apply a brief intervention in passive smoking after specific training and the control group will apply the habitual care.Discussion: Exposure to ETS is an avoidable factor related to infant morbimortality. Interventions to reduce exposure to ETS in babies are potentially beneficial for their health. The BIBE study evaluates an intervention to reduce exposure to ETS that takes advantage of pediatric visits. Interventions in the form of advice, conducted by pediatric professionals, are an excellent opportunity for prevention and protection of infants against the harmful effects of ETS.

Si3N4 single-crystal nanowires grown from silicon micro- and nanoparticles near the threshold of passive oxidation

A simple and most promising oxide-assisted catalyst-free method is used to prepare silicon nitride nanowires that give rise to high yield in a short time. After a brief analysis of the state of the art, we reveal the crucial role played by the oxygen partial pressure: when oxygen partial pressure is slightly below the threshold of passive oxidation, a high yield inhibiting the formation of any silica layer covering the nanowires occurs and thanks to the synthesis temperature one can control nanowire dimensions

Venture capital meets contract theory: risky claims or formal control?

This paper develops a theory of the joint allocation of formal control and cash-flow rights in venture capital deals. We argue that when the need for investor support calls for very high-powered outside claims, entrepreneurs should optimally retain formal control in order to avoid excessive interference. Hence, we predict that risky claims should be be negatively correlated to control rights, both along the life of a start-up and across deals. This challenges the idea that risky claims should a ways be associated to more formal control, and is in line with contractual terms increasingly used in venture capital, in corporate venturing and in partnership deals between biotech start-ups and large drug companies. The paper provides a theoretical explanation to some puzzling evidence documented in Gompers (1997) and Kaplan and Stromberg (2000), namely the inclusion in venture capital contracts of contingencies that trigger both a reduction in VC control and the conversion! of her preferred stocks into common stocks.

Estudi de casos pel control de síntesi d’instruments musicals virtuals mitjançant la veu cantada

Report for the scientific sojourn carried out at the Music Technology Area (Sound Processing and Control Lab), Faculty of Music, McGill University, Montreal, Canada, from October to December 2005.The aim of this research is to study the singing voice for controlling virtual musical instrument synthesis. It includes analysis and synthesis algorithms based on spectral audio processing. After digitalising the acoustic voice signal in the computer, a number of expressive descriptors of the singer are extracted. This process is achieved synchronously, thus all the nuance of the singer performance have been tracked. In a second stage, the extracted parameters are mapped to a sound synthesizer, the so-called digital musical instruments. In order achieve it, several tests with music students of the Faculty of Music, McGill University have been developed. These experiments have contributed to evaluate the system and to derive new control strategies to integrate: clarinet synthesis, bass guitar, visual representation of voice signals.

Freedom of choice as control over outcomes

As interactions between individuals are introduced into the freedom of choice literature by the mean of game forms, new issues appear. In particular, in this paper it is argued that individuals face uncertainty with respect to outcomes as they lose the control they implicitely exert over options in the opportunity set framework. A criterion is proposed as to compare alternative game forms in terms of the control they offer to individuals. The CardMin criterion suggests that any game form should be judged on the basis of the strategy offering the lowest number of pairwise different outcomes. An axiomatic characterization is provided in the case of two individuals.

El cop de sol en pomera: causes i control

En les condicions climàtiques del Sud d’Europa, el cop de sol és un dels factors que més incideixen en la reducció del percentatge de fruits de primera categoria, especialment en certes varietats com ‘Granny Smith’, ‘Fuji’ o ‘Gala’. Existeixen encara certs dubtes respecte les causes del desenvolupament del cop de sol, tot i que està àmpliament acceptat que les altes temperatures del fruit hi juguen un paper important. En canvi, existeix més debat pel que fa al paper de la radiació. Els mecanismes fisiològics causants dels símptomes del cop de sol no són del tot clars. Existeixen diferents hipòtesis, des de la necrosis dels teixits fins a la degradació de pigments en funció del grau de cop de sol. El mètode més efectiu pel seu control és la selecció minuciosa de varietats ben adaptades a les condicions climàtiques locals, ja que mostren diferències en quant a la sensibilitat al cop de sol. Altres experiències de control avaluades en diferents zones del món inclouen la protecció amb xarxes antipedra, refrescament evaporatiu mitjançant reg per aspersió i aplicació d’un film de partícules de caolí amb diferents graus d’èxit i implementació.

La revegetació en el control biològic de plagues

Una de les estratègies de control de les plagues d’insectes que s’estan imposant actualment és l’aplicació de programes de control integrat. Es basa a aprofitar totes les eines de control de plagues disponibles per aconseguir mantenir les poblacions d’insectes per davall d’un llindar determinat de danys. Entre les tècniques que s’utilitzen hi ha les mesures culturals, el control biològic i el control químic mitjançant insecticides específics. El control biològic es fonamenta en la utilització d’enemics naturals dels insectes plaga per controlar- ne les poblacions. Els enemics naturals poden ser parasitoides, depredadors i patògens. El control biològic pot basar-se tant en la inoculació d’enemics naturals exòtics o autòctons com en la conservació i/o augment d’enemics naturals presents en el medi. Per al control biològic de plagues en cultius hortícoles a l’àrea mediterrània s’està utilitzant majoritàriament la conservació i l’augment d’enemics naturals.

Los aceites minerales insecticidas en programas de Control Integrado de las plagas de los cítricos

Los agroecosistemas suelen tener un número reducido de especies. Sin embargo, el de los cítricos es muy rico tanto en organismos perjudiciales como beneficiosos. En él existen tres plagas (Icerya purchasi, Aleurothrixus floccosus y Panonychus citri) que pueden considerarse muy bien controladas por sus enemigos naturales y que por tanto habrá que tener siempre en cuenta a la hora de realizar cualquier intervención química. Por ello, la introducción accidental de una nueva plaga, como es Phyllocnistis citrella, puede alterar los programas de Control Integrado existentes. Los ataques más importantes de P.citrella en plantaciones adultas de cítricos se producen en la brotación de finales del verano. En este momento las poblaciones de los principales entomófagos del cultivo -Rodolia cardinalis, Cales noacki y Euseius stipulatus- son bajas, por lo que es fundamental elegir productos selectivos que los afecten lo menos posible y respeten el equilibrio plaga-entomófago. Así mismo, la proximidad de la cosecha obliga elegir materias activas que no originen problemas de residuos en la comercialización de los frutos. El empleo de aceites minerales insecticidas data de finales del siglo pasado. Desde entonces han desaparecido varias generaciones de insecticidas por problemas de resistencias, toxicidad, persistencia en el ambiente, etc. Sin embargo, los aceites minerales se han venido utilizando continuada y eficazmente en la protección de los cultivos, siguiendo el perfil de un desarrollo sostenido, y son considerados como una herramienta eficaz en la protección integrada de cultivos.