O contributo das redes sociais no processo de rebranding

Relatório de estágio de mestrado em Ciências da Comunicação (área de especialização em Publicidade e Relações Públicas)

Antibacterial properties of multifunctional coatings Ag-ZrCN for biomedical devices: a novel approach

PhD in Sciences Specialty in Physics

Operation modes for the electric vehicle in smart grids and smart homes : present and proposed modes

This paper presents the main operation modes for an electric vehicle (EV) battery charger framed in smart grids and smart homes, i.e., are discussed the present-day and are proposed new operation modes that can represent an asset towards EV adoption. Besides the well-known grid to vehicle (G2V) and vehicle to grid (V2G), this paper proposes two new operation modes: Home-to-vehicle (H2V), where the EV battery charger current is controlled according to the current consumption of the electrical appliances of the home (this operation mode is combined with the G2V and V2G); Vehicle-for-grid (V4G), where the EV battery charger is used for compensating current harmonics or reactive power, simultaneously with the G2V and V2G operation modes. The vehicle-to-home (V2H) operation mode, where the EV can operate as a power source in isolated systems or as an off-line uninterruptible power supply to feed priority appliances of the home during power outages of the electrical grid is presented in this paper framed with the other operation modes. These five operation modes were validated through experimental results using a developed 3.6 kW bidirectional EV battery charger prototype, which was specially designed for these operation modes. The paper describes the developed EV battery charger prototype, detailing the power theory and the voltage and current control strategies used in the control system. The paper presents experimental results for the various operation modes, both in steady-state and during transients.

El valor razonable como concepto vinculado a la pertinencia del valor. Fair value as a concept related to value relevance.

IDENTIFICACIÓN Y CARACTERIZACIÓN DEL PROBLEMA - HIPÓTESIS Según la NIC 39, el valor razonable es la cantidad por la que puede ser intercambiado un activo o cancelado un pasivo entre un comprador y un vendedor interesados y debidamente informados, en condiciones de independencia mutua. La definición del FASB (SFAC 7) es muy similar, y define el valor razonable como el monto mediante el que un activo podría ser enajenado en una transacción entre partes independientes, dispuestas a realizar la operación en situaciones diferentes a la de una liquidación o a la de una venta forzada. Puede apreciarse que esta definición de valor razonable es limitada porque, a excepción de escenarios que se correspondan con mercados perfectos y completos, el concepto puede abarcar valores de entrada, valores de salida y valores en uso, los cuales pueden ser muy diferentes (Beaver, 1987). El valor de entrada es el valor de adquisición o de reemplazo, el valor de salida es el precio al cual un activo puede ser vendido o liquidado, y el valor en uso es el valor incremental de una empresa atribuible a un activo (se correspondería con el valor presente mencionado anteriormente). Dado que el IASB y la FASB se ocupan de la valuación de activos que una empresa posee, y no de activos que serán adquiridos en un futuro, su definición de valor razonable debería ser interpretada desde la perspectiva del vendedor. Por lo tanto, el concepto de valor razonable que manejan el IASB y la FASB se asemeja a un valor de salida, tal como lo propusieron Chambers y Stirling hace bastantes años atrás.Planteado esto, lo que tratará de dilucidar este proyecto de investigación es si este concepto de valor razonable es realmente novedoso o es una simple regresión a los valores corrientes de salida defendidos por los autores de la década del setenta. OBJETIVOS GENERALES Y ESPECÍFICOS General Analizar si el concepto “valor razonable” tal como es definido por la normativa actual se corresponde con una definición novedosa o es una adaptación/modificación/regresión de conceptos ya existentes (valores corrientes de salida). Específicos Revisar la literatura específica desde el punto de vista de la teoría contable y las normas de las que dispone la profesión referidas a los siguientes aspectos: a) Valores corrientes b) Valor razonable MATERIALES Y MÉTODOS El análisis que se llevará a cabo comprenderá dos aspectos. El primero consiste en la revisión de la doctrina contable. Para ello se analizará bibliografía significativa y trabajos de eventos académicos relacionados con el valor razonable. En segundo término se revisará la normativa profesional a nivel nacional e internacional. Después de concluido con los pasos anteriores se analizará la novedad del concepto valor razonable y su semejanza con el valor corriente de salida planteado por los autores de la década del setenta. IMPORTANCIA DEL PROYECTO – IMPACTO Se pretende revisar si el concepto valor razonable planteado por la normativa actual resulta realmente novedoso o es una adaptación de viejos conceptos planteados en la década del setenta del siglo pasado. El proyecto resulta importante porque es un tema no desarrollado en la literatura, ni planteado en congresos. Se estima lograr material de publicación y presentación en eventos académicos. According to the NIC 39, fair value is the quantity for the one that can be exchanged an asset or cancelled a liability between a buyer and a seller interested and due informed, in conditions of mutual independence. The definition of the FASB (SFAC 7) is very similar, and defines fair value as the amount by means of which an assets might be alienated in a transaction between independent parts, ready to realize the operation in situations different from that of a liquidation or to that of a forced sale. This definition of reasonable value is limited because, with the exception of scenes that fit with perfect and complete markets, the concept can include values of entry, values of exit and values in use, which can be very different (Beaver, 1987). The value of entry is the value of acquisition or of replacement, the value of exit is the price to which an asset can be sold or liquidated, and the value in use is the incremental value of a company attributable to an asset. Provided that the IASB and the FASB deal with the appraisal of assets that a company possesses, and not of assets that will be acquired in a future, this definition of fair value should be interpreted from the perspective of the seller. Therefore, the concept of reasonable value that they handle the IASB and the FASB is alike a value of exit, as Chambers and Stirling proposed it enough years ago behind. We will review if the concept of "fair value" is really new or if it is an adaptation of old concepts.

On the identification of monetary (and other) shocks

The purpose of this paper is twofold. First, we construct a DSGE model which spells out explicitly the instrumentation of monetary policy. The interest rate is determined every period depending on the supply and demand for reserves which in turn are affected by fundamental shocks: unforeseeable changes in cash withdrawal, autonomous factors, technology and government spending. Unexpected changes in the monetary conditions of the economy are interpreted as monetary shocks. We show that these monetary shocks have the usual effects on economic activity without the need of imposing additional frictions as limited participation in asset markets or sticky prices. Second, we show that this view of monetary policy may have important consequences for empirical research. In the model, the contemporaneous correlations between interest rates, prices and output are due to the simultaneous effect of all fundamental shocks. We provide an example where these contemporaneous correlations may be misinterpreted as a Taylor rule. In addition, we use the sign of the impact responses of all shocks on output, prices and interest rates derived from the model to identify the sources of shocks in the data.

Taxation of banks: a theoretical framework

The goal of this paper is to develop a model of financial intermediation analyze the impact of various forms of taxation. The model considers in a unified framework various functions of banks: monitoring, transaction services and asset transformation. Particular attention is devoted to conditions for separability between deposits and loans. The analysis focuses on: (i) competition between banks and alternative financial arrangements (investment funds and organized security markets), (ii) regulation, and (iii) bank's monopoly power and risk taking behavior.

Stock market volatility and learning

Introducing bounded rationality in a standard consumption-based asset pricing model with time separable preferences strongly improves empirical performance. Learning causes momentum and mean reversion of returns and thereby excess volatility, persistence of price-dividend ratios, long-horizon return predictability and a risk premium, as in the habit model of Campbell and Cochrane (1999), but for lower risk aversion. This is obtained, even though our learning scheme introduces just one free parameter and we only consider learning schemes that imply small deviations from full rationality. The findings are robust to the learning rule used and other model features. What is key is that agents forecast future stock prices using past information on prices.

In Search of a theory of debt management

A growing literature integrates theories of debt management into models of optimal fiscal policy. One promising theory argues that the composition of government debt should be chosen so that fluctuations in the market value of debt offset changes in expected future deficits. This complete market approach to debt management is valid even when the government only issues non-contingent bonds. A number of authors conclude from this approach that governments should issue long term debt and invest in short term assets. We argue that the conclusions of this approach are too fragile to serve as a basis for policy recommendations. This is because bonds at different maturities have highly correlated returns, causing the determination of the optimal portfolio to be ill-conditioned. To make this point concrete we examine the implications of this approach to debt management in various models, both analytically and using numerical methods calibrated to the US economy. We find the complete market approach recommends asset positions which are huge multiples of GDP. Introducing persistent shocks or capital accumulation only worsens this problem. Increasing the volatility of interest rates through habits partly reduces the size of these simulations we find no presumption that governments should issue long term debt ? policy recommendations can be easily reversed through small perturbations in the specification of shocks or small variations in the maturity of bonds issued. We further extend the literature by removing the assumption that governments every period costlessly repurchase all outstanding debt. This exacerbates the size of the required positions, worsens their volatility and in some cases produces instability in debt holdings. We conclude that it is very difficult to insulate fiscal policy from shocks by using the complete markets approach to debt management. Given the limited variability of the yield curve using maturities is a poor way to substitute for state contingent debt. The result is the positions recommended by this approach conflict with a number of features that we believe are important in making bond markets incomplete e.g allowing for transaction costs, liquidity effects, etc.. Until these features are all fully incorporated we remain in search of a theory of debt management capable of providing robust policy insights.

Three essays on the psychology of investment and financial markets

Préface My thesis consists of three essays where I consider equilibrium asset prices and investment strategies when the market is likely to experience crashes and possibly sharp windfalls. Although each part is written as an independent and self contained article, the papers share a common behavioral approach in representing investors preferences regarding to extremal returns. Investors utility is defined over their relative performance rather than over their final wealth position, a method first proposed by Markowitz (1952b) and by Kahneman and Tversky (1979), that I extend to incorporate preferences over extremal outcomes. With the failure of the traditional expected utility models in reproducing the observed stylized features of financial markets, the Prospect theory of Kahneman and Tversky (1979) offered the first significant alternative to the expected utility paradigm by considering that people focus on gains and losses rather than on final positions. Under this setting, Barberis, Huang, and Santos (2000) and McQueen and Vorkink (2004) were able to build a representative agent optimization model which solution reproduced some of the observed risk premium and excess volatility. The research in behavioral finance is relatively new and its potential still to explore. The three essays composing my thesis propose to use and extend this setting to study investors behavior and investment strategies in a market where crashes and sharp windfalls are likely to occur. In the first paper, the preferences of a representative agent, relative to time varying positive and negative extremal thresholds are modelled and estimated. A new utility function that conciliates between expected utility maximization and tail-related performance measures is proposed. The model estimation shows that the representative agent preferences reveals a significant level of crash aversion and lottery-pursuit. Assuming a single risky asset economy the proposed specification is able to reproduce some of the distributional features exhibited by financial return series. The second part proposes and illustrates a preference-based asset allocation model taking into account investors crash aversion. Using the skewed t distribution, optimal allocations are characterized as a resulting tradeoff between the distribution four moments. The specification highlights the preference for odd moments and the aversion for even moments. Qualitatively, optimal portfolios are analyzed in terms of firm characteristics and in a setting that reflects real-time asset allocation, a systematic over-performance is obtained compared to the aggregate stock market. Finally, in my third article, dynamic option-based investment strategies are derived and illustrated for investors presenting downside loss aversion. The problem is solved in closed form when the stock market exhibits stochastic volatility and jumps. The specification of downside loss averse utility functions allows corresponding terminal wealth profiles to be expressed as options on the stochastic discount factor contingent on the loss aversion level. Therefore dynamic strategies reduce to the replicating portfolio using exchange traded and well selected options, and the risky stock.

An empirical analysis of wealth taxation: equity Vs.tax compliance

Capital taxation is currently under debate, basically due to problems of administrative control and proper assessment of the levied assets. We analyze both problems focusing on a capital tax, the annual wealth tax (WT), which is only applied in five OECD countries, being Spain one of them. We concentrate our analysis on top 1% adult population, which permits us to describe the evolution of wealth concentration in Spain along 1983-2001. On average top 1% holds about 18% of total wealth, which rises to 19% when tax incompliance and under-assessment is corrected for housing, the main asset. The evolution suggests wealth concentration has risen. Regarding WT, we analyze whether it helps to reduce wealth inequality or, on the contrary, it reinforces vertical inequity (due to especial concessions) and horizontal inequity (due to the de iure and to de facto different treatment of assets). We analyze in detail housing and equity shares. By means of a time series analysis, we relate the reported values with reasonable price indicators and proxies of the propensity to save. We infer net tax compliance is extremely low, which includes both what we commonly understand by (gross) tax compliance and the degree of under-assessment due to fiscal legislation (for housing). That is especially true for housing, whose level of net tax compliance is well below 50%. Hence, we corroborate the difficulties in taxing capital, and so cast doubts on the current role of the WT in Spain in reducing wealth inequality.

Dynamic Option Adjusted Spread and the Value of Mortgage Backed Securities (Draft 1)

We extend a reduced form model for pricing pass-through mortgage backed securities (MBS) and provide a novel hedging tool for investors in this market. To calculate the price of an MBS, traders use what is known as option-adjusted spread (OAS). The resulting OAS value represents the required basis points adjustment to reference curve discounting rates needed to match an observed market price. The OAS suffers from some drawbacks. For example, it remains constant until the maturity of the bond (thirty years in mortgage-backed securities), and does not incorporate interest rate volatility. We suggest instead what we call dynamic option adjusted spread (DOAS). The latter allows investors in the mortgage market to account for both prepayment risk and changes of the yield curve.

Can a Lucas model with habit generate realistic conditional volatility in exchange rate returns?

In this paper, we attempt to give a theoretical underpinning to the well established empirical stylized fact that asset returns in general and the spot FOREX returns in particular display predictable volatility characteristics. Adopting Moore and Roche s habit persistence version of Lucas model we nd that both the innovation in the spot FOREX return and the FOREX return itself follow "ARCH" style processes. Using the impulse response functions (IRFs) we show that the baseline simulated FOREX series has "ARCH" properties in the quarterly frequency that match well the "ARCH" properties of the empirical monthly estimations in that when we scale the x-axis to synchronize the monthly and quarterly responses we find similar impulse responses to one unit shock in variance. The IRFs for the ARCH processes we estimate "look the same" with an approximately monotonic decreasing fashion. The Lucas two-country monetary model with habit can generate realistic conditional volatility in spot FOREX return.

On the Relationship between Market Power and Bank Risk Taking

We analyse risk-taking behaviour of banks in the context of spatial competition. Banks mobilise unsecured deposits by offering deposit rates, which they invest either in a prudent or a gambling asset. Limited liability along with high return of a successful gamble induce moral hazard at the bank level. We show that when the market power is low, banks invest in the gambling asset. On the other hand, for sufficiently high levels of market power, all banks choose the prudent asset to invest in. We further show that a merger of two neighboring banks increases the likelihood of prudent behaviour. Finally, introduction of a deposit insurance scheme exacerbates banks’ moral hazard problem.

A Model of Near-Rational Exuberance

We study how the use of judgement or “add-factors” in forecasting may disturb the set of equilibrium outcomes when agents learn using recursive methods. We isolate conditions under which new phenomena, which we call exuberance equilibria, can exist in a standard self-referential environment. Local indeterminacy is not a requirement for existence. We construct a simple asset pricing example and find that exuberance equilibria, when they exist, can be extremely volatile relative to fundamental equilibria.

Hawtreyan “Credit Deadlock” or Keynesian “Liquidity Trap”? Lessons for Japan from the Great Depression

This paper outlines the ideas of Ralph Hawtrey and Lauchlin Currie on the need for monetised fiscal deficit spending in 1930s USA to combat the deep depression into which the economy had been allowed to sink. In such exceptional circumstances of “credit deadlock” in which banks were afraid to lend and households and business afraid to borrow, the deadlock could best be broken through the spending of new money into circulation via large fiscal deficits. This complementarity of fiscal and monetary policy was shown to be essential, and as such indicates the potential power of monetary policy – in contrast to the Keynesian “liquidity trap” view that it is powerless This lesson was not learned by the Japanese authorities in their response to the asset price collapse of 1991-92, resulting in a lost decade as ballooning fiscal deficits were neutralised throughout the 1990s by unhelpfully tight monetary policy with the Bank of Japan refusing to monetise the deficits.