Monitoring switch-type sensors and powering autonomous sensors via inductive coupling: application to removable seats in vehicles

Aquesta tesi explora la possibilitat de fer servir enllaços inductius per a una aplicació de l’automòbil on el cablejat entre la centraleta (ECU) i els sensors o detectors és difícil o impossible. S’han proposat dos mètodes: 1) el monitoratge de sensors commutats (dos possibles estats) via acoblament inductiu i 2) la transmissió mitjançant el mateix principi físic de la potència necessària per alimentar els sensors autònoms remots. La detecció d'ocupació i del cinturó de seguretat per a seients desmuntables pot ser implementada amb sistemes sense fils passius basats en circuits ressonants de tipus LC on l'estat dels sensors determina el valor del condensador i, per tant, la freqüència de ressonància. Els canvis en la freqüència són detectats per una bobina situada en el terra del vehicle. S’ha conseguit provar el sistema en un marge entre 0.5 cm i 3 cm. Els experiments s’han dut a terme fent servir un analitzador d’impedàncies connectat a una bobina primària i sensors comercials connectats a un circuit remot. La segona proposta consisteix en transmetre remotament la potència des d’una bobina situada en el terra del vehicle cap a un dispositiu autònom situat en el seient. Aquest dispositiu monitorarà l'estat dels detectors (d'ocupació i de cinturó) i transmetrà les dades mitjançant un transceptor comercial de radiofreqüència o pel mateix enllaç inductiu. S’han avaluat les bobines necessàries per a una freqüència de treball inferior a 150 kHz i s’ha estudiat quin és el regulador de tensió més apropiat per tal d’aconseguir una eficiència global màxima. Quatre tipus de reguladors de tensió s’han analitzat i comparat des del punt de vista de l’eficiència de potència. Els reguladors de tensió de tipus lineal shunt proporcionen una eficiència de potència millor que les altres alternatives, els lineals sèrie i els commutats buck o boost. Les eficiències aconseguides han estat al voltant del 40%, 25% i 10% per les bobines a distàncies 1cm, 1.5cm, i 2cm. Les proves experimentals han mostrat que els sensors autònoms han estat correctament alimentats fins a distàncies de 2.5cm.

Simulation methods with extended stability for stiff biochemical kinetics

Background: With increasing computer power, simulating the dynamics of complex systems in chemistry and biology is becoming increasingly routine. The modelling of individual reactions in (bio)chemical systems involves a large number of random events that can be simulated by the stochastic simulation algorithm (SSA). The key quantity is the step size, or waiting time, τ, whose value inversely depends on the size of the propensities of the different channel reactions and which needs to be re-evaluated after every firing event. Such a discrete event simulation may be extremely expensive, in particular for stiff systems where τ can be very short due to the fast kinetics of some of the channel reactions. Several alternative methods have been put forward to increase the integration step size. The so-called τ-leap approach takes a larger step size by allowing all the reactions to fire, from a Poisson or Binomial distribution, within that step. Although the expected value for the different species in the reactive system is maintained with respect to more precise methods, the variance at steady state can suffer from large errors as τ grows. Results: In this paper we extend Poisson τ-leap methods to a general class of Runge-Kutta (RK) τ-leap methods. We show that with the proper selection of the coefficients, the variance of the extended τ-leap can be well-behaved, leading to significantly larger step sizes.Conclusions: The benefit of adapting the extended method to the use of RK frameworks is clear in terms of speed of calculation, as the number of evaluations of the Poisson distribution is still one set per time step, as in the original τ-leap method. The approach paves the way to explore new multiscale methods to simulate (bio)chemical systems.

Explaining parental dedication to child care in Spain

The quality of the time dedicated to child care has potential positive effects on children’s life chances. However, the determinants of parental time allocation to child care remain largely unexplored, particularly in context undergoing rapid family change such as Spain. We assess two alternative explanations for differences between parents in the amount of time spent with children. The first, based in the relative resources hypothesis, links variation in time spent with children to the relative attributes (occupation, education or income) of one partner to the other. The second, derived from the social status hypothesis, suggests that variation in time spent with children is attributable to the relative social position of the pair (i.e. higher status couples spend more time with children regardless of within-couple difference).To investigate theses questions, we use a sample of adults (18-50) from the Spanish Time Use Survey (STUS) 2002-2003 (n=7,438). Limiting the analysis to adults who are married or in consensual unions, the STUS allows to assess both the quantity and quality of parental time spent with children. We find little support for the “relative resources hypothesis”. Instead, consistent with the “social status hypothesis”, we find that time spent on child care is attributable to the social position of the couple, regardless of between-parent differences in income of education.

Productivity Growth during the English Industrial Revolution: A Dual Approach

This paper presents new estimates of total factor productivity growth in Britain for the period 1770-1860. We use a dual technique recently popularized by Hsieh (1999), and argue that the estimates we derive from factor prices are of similar quality to quantity-based calculations. Our results provide further evidence, derived from this independent set of sources, that productivity growth during the British Industrial Revolution was relatively slow. During the years 1770-1800, TFP growth was close to zero, according to our estimates. The period 1800-1830 experienced an acceleration of productivity growth. The Crafts-Harley view of the Industrial Revolution is thus reinforced. We also consider alternative explanations of slow productivity growth, and reject the interpretation that focuses on the introduction of steam as a general purpose technology.

Cyclical Skill-Biased Technological Change

Over the past two decades, technological progress has been biased towards making skilled labor more productive. The evidence for this finding is based on the persistent parallel increase in the skill premium and the supply of skilled workers. What are the implications of skill-biased technological change for the business cycle? To answer this question, we use the CPS outgoing rotation groups to construct quarterly series for the price and quantity of skill. The unconditional correlation of the skill premium with the cycle is zero. However, using a structural VAR with long run restrictions, we find that technology shocks substantially increase the premium. Investment-specific technology shocks are not skill-biased and our findings suggest that capital and skill are (mildly) substitutable in aggregate production.

Drama i espectacle operístic : la dialèctica entre espai i temps en el Parsifal de Herheim i el ritus com a obra d’art del futur

Parsifal és, segons la manera en què es mire, l’excepció dins el llistat de drames musicals wagnerians pel tractament sense precedents que fa de motius catòlics en un lloc i un moment com la recentment unificada Alemanya, on la construcció de la identitat nacional passava per un model social i cultural concret i, per tant, també religiós. Però una òptica diferent ens pot apropar a una ingent quantitat de paral·lelismes entre el model artístic expressat per Wagner en els seus escrits teòrics de joventut i alguns dels elements estètics i ideològics de la seua darrera obra. L’espectacle operístic en l’actualitat continua sent fruit de la societat en què es gesta i per això Stefan Herheim utilitza una visió diacrònica de la recepció d’aquesta obra wagneriana com a un dels motius principals sobre els quals construirà una dramatúrgia densa i meditada en què es durà a terme fins a les seues últimes conseqüències una revisió en clau contemporània del concepte d’obra d’art del futur.

Federico II de Prusia : el rey flautista

En un momento histórico en el que las tendencias musicales en Europa estaban a medio camino entre el Barroco y el Clasicismo, confluyeron en la corte de Federico el Grande una serie de músicos que trabajaron para el rey prusiano y que compusieron una gran cantidad de música para flauta, instrumento que él tocaba. La actividad musical del Berlín de esos años se convirtió así en relevante para el mundo flautístico. Profundizaremos en este trabajo en la figura del monarca, en la relación de éste con sus músicos y en las características principales de la música de la segunda mitad del siglo XVIII.

Dynamic price competition with fixed capacities

Many revenue management (RM) industries are characterized by (a) fixed capacities in theshort term (e.g., hotel rooms, seats on an airline flight), (b) homogeneous products (e.g., twoairline flights between the same cities at similar times), and (c) customer purchasing decisionslargely influenced by price. Competition in these industries is also very high even with just twoor three direct competitors in a market. However, RM competition is not well understood andpractically all known implementations of RM software and most published models of RM donot explicitly model competition. For this reason, there has been considerable recent interestand research activity to understand RM competition. In this paper we study price competitionfor an oligopoly in a dynamic setting, where each of the sellers has a fixed number of unitsavailable for sale over a fixed number of periods. Demand is stochastic, and depending on howit evolves, sellers may change their prices at any time. This reflects the fact that firms constantly,and almost costlessly, change their prices (alternately, allocations at a price in quantity-basedRM), reacting either to updates in their estimates of market demand, competitor prices, orinventory levels. We first prove existence of a unique subgame-perfect equilibrium for a duopoly.In equilibrium, in each state sellers engage in Bertrand competition, so that the seller withthe lowest reservation value ends up selling a unit at a price that is equal to the equilibriumreservation value of the competitor. This structure hence extends the marginal-value conceptof bid-price control, used in many RM implementations, to a competitive model. In addition,we show that the seller with the lowest capacity sells all its units first. Furthermore, we extendthe results transparently to n firms and perform a number of numerical comparative staticsexploiting the uniqueness of the subgame-perfect equilibrium.

Credit rationing and crowding out during the Industrial Revolution: Evidence from Hoare's Bank, 1702-1862

Crowding-out during the British Industrial Revolution has long been one of the leadingexplanations for slow growth during the Industrial Revolution, but little empirical evidence exists to support it. We argue that examinations of interest rates are fundamentally misguided, and that the eighteenth- and early nineteenth-century private loan market balanced through quantity rationing. Using a unique set of observations on lending volume at a London goldsmith bank, Hoare s, we document the impact of wartime financing on private credit markets. We conclude that there is considerable evidence that government borrowing, especially during wartime, crowded out private credit.

Factor prices and productivity growth during the British Industrial Revolution

This paper presents new estimates of total factor productivity growth in Britain for the period1770 1860. We use the dual technique and argue that the estimates we derive from factorprices are of similar quality to quantity-based calculations. Our results provide further evidence,calculated on the basis of an independent set of sources, that productivity growth duringthe British Industrial Revolution was relatively slow. The Crafts Harley view of theIndustrial Revolution is thus reinforced. Our preferred estimates suggest a modest accelerationafter 1800.

On the relevance of modeling volatility for pricing purposes

This paper presents a two-factor (Vasicek-CIR) model of the term structure of interest rates and develops its pricing and empirical properties. We assume that default free discount bond prices are determined by the time to maturity and two factors, the long-term interest rate and the spread. Assuming a certain process for both factors, a general bond pricing equation is derived and a closed-form expression for bond prices is obtained. Empirical evidence of the model's performance in comparisson with a double Vasicek model is presented. The main conclusion is that the modeling of the volatility in the long-term rate process can help (in a large amount) to fit the observed data can improve - in a reasonable quantity - the prediction of the future movements in the medium- and long-term interest rates. However, for shorter maturities, it is shown that the pricing errors are, basically, negligible and it is not so clear which is the best model to be used.

Endogenous Stackelberg leadership

We consider a linear quantity setting duopoly game and analyzewhich of the players will commit when both players have the possibility todo so. To that end, we study a 2-stage game in which each player caneither commit to a quantity in stage 1 or wait till stage 2. We show thatcommitting is more risky for the high cost firm and that, consequently,risk dominance considerations, as in Harsanyi and Selten (1988), allowthe conclusion that only the low cost firm will choose to commit.Hence, the low cost firm will emerge as the endogenous Stackelberg leader.

Immigration and the survival of the welfare state

This paper analyzes the political sustainability of the welfare state in a model where immigration policy is also endogenous. In the model, the skills of the native population are affected by immigration and skill accumulation. Moreover, immigrants affect future policies, once they gain the right to vote. The main finding is that the long-run survival of redistributive policies is linked to an immigration policy specifying both skill and quantity restrictions. In particular, in steady state the unskilled majority admits a limited inflow of unskilled immigrants in order to offset growth in the fraction of skilled voters and maintain a high degree of income redistribution.Interestingly, equilibrium immigration policy shifts from unrestricted skilled immigration,when the country is skill-scarce, to restricted unskilled immigration, as the fraction of native skilled workers increases. The analysis also suggests a new set of variables that may help explain international differences in immigration restrictions.

Drug innovation, prices and health

This article tries to reconcile economic-industrial policy with health policy when dealing with biomedical innovation and welfare state sustainability. Better health accounts for an increasingly large proportion of welfare improvements. Explanation is given to the welfare losses coming from the fact than industrial and health policy tend to ignore each other. Drug s prices reflecting their relative relative effectiveness send the right signal to the industry rewarding innovation with impact on quantity and quality of life- and to the buyers of health care services.The level of drug s public reimbursement indicates the social willingness to pay of the different national health systems, not only by means of inclusion, or rejection, in the basket of services covered, but especially establishing the proportion of the price that is going to be financed publicly.Reference pricing for therapeutic equivalents as the upper limit of the social willingness to pay- and two-tiered co-payments for users (avoidable and inversely related with the incremental effectiveness of de drug) are deemed appropriate for those countries concerned at the same time with increasing their productivity and maintaining its welfare state. Profits drive R&D but not its location. There is no intrinsic contradiction between high productivity and a consolidated National Health Service (welfare state) as the European Nordic Countries are telling us every day.

The impact of generic reference pricing interventions in the statin market

The objective of this study was to evaluate the intended and unintended impact on pharmaceutical use and sales of three public financing reforms applied to the prescription of statins: a Spanish generic reference pricing (RP) system for lovastatin and simvastatin, and two competing policies introduced by the Andalusian Public Health Service (APHS) for all statins, first a maximum consumer price (MCP) and then a so called quality prescribing incentive for general practitioners (MCP plus PI).This study is designed as an observational, retrospective, interrupted time series analysis with comparison series (APHS and the rest of Spain) of 46 monthly drug use and sales ratios from January 2001 to October 2004 for each active ingredient in the group of statins.RP has been effective at reducing the volume of sales growth of the off-patent statins, yet its overall impact on sales of all statins has been relatively modest. The quantity and volume of sales impact heavily depends on regulatory RP details such as when the system is introduced, how often it is updated, and how the reference price is calculated.