A public key encryption based on third order linear sequences

Based on third order linear sequences, an improvement version of the Diffie-Hellman distribution key scheme and the ElGamal public key cryptosystem scheme are proposed, together with an implementation and computational cost. The security relies on the difficulty of factoring an RSA integer and on the difficulty of computing the discrete logarithm.

Public policy for entrepreneurship and innovation: impact in managed and entrepreneurial economies

Many of the most advanced economies of the world have undergone significant transformation in the last few decades. Globalization and technological changes, especially developments in information technologies, have helped to stimulate this transformation. These have contributed to changing institutional frameworks in many respects within the economies including adjustments to economic policies. The results of these transformations take many different forms and are manifested in different areas of an economy. At the heart of these changes however, has been the increasingly important role of entrepreneurship in the economy. The transformed ("new") economy stimulates and supports activities in innovation and entrepreneurship and is labelled the entrepreneurial economy. The "old" economy on the other hand restricts such activities and is referred to as the managed economy (Audretsch & Thurik, 2001).

Redistributive taxation, public expenditure, and size of governent

We introduce a model of redistributive income taxation and public expenditure. This joint treatment permits analyzing the interdependencies between the two policies: one cannot be chosen independently of the other. Empirical evidence reveals that partisan confrontation essentially falls on expenditure policies rather than on income taxation. We examine the case in which the expenditure policy (or the size of government) is chosen by majority voting and income taxation is consistently adjusted. This adjustment consists of designing the income tax schedule that, given the expenditure policy, achieves consensus among the population. The model determines the consensus in- come tax schedule, the composition of public expenditure and the size of government. The main results are that inequality is negatively related to the size of government and to the pro-rich bias in public expenditure, and positively or negatively related to the marginal income tax, depending on substitutability between government supplied and market goods. These implications are validated using OECD data.

Knowledge of Catalan, public/private sector choice and earnings: Evidence from a double sample selection model

This paper explores the earnings return to Catalan knowledge for public and private workers in Catalonia. In doing so, we allow for a double simultaneous selection process. We consider, on the one hand, the non-random allocation of workers into one sector or another, and on the other, the potential self-selection into Catalan proficiency. In addition, when correcting the earnings equations, we take into account the correlation between the two selectivity rules. Our findings suggest that the apparent higher language return for public sector workers is entirely accounted for by selection effects, whereas knowledge of Catalan has a significant positive return in the private sector, which is somewhat higher when the selection processes are taken into account.

Public and private learning from prices, strategic substitutability and complementarity, and equilibrium multiplicity

We study a general static noisy rational expectations model where investors have private information about asset payoffs, with common and private components, and about their own exposure to an aggregate risk factor, and derive conditions for existence and uniqueness (or multiplicity) of equilibria. We find that a main driver of the characterization of equilibria is whether the actions of investors are strategic substitutes or complements. This latter property in turn is driven by the strength of a private learning channel from prices, arising from the multidimensional sources of asymmetric information, in relation to the usual public learning channel. When the private learning channel is strong (weak) in relation to the public we have strong (weak) strategic complementarity in actions and potentially multiple (unique) equilibria. The results enable a precise characterization of whether information acquisition decisions are strategic substitutes or complements. We find that the strategic substitutability in information acquisition result obtained in Grossman and Stiglitz (1980) is robust. JEL Classification: D82, D83, G14 Keywords: Rational expectations equilibrium, asymmetric information, risk exposure, hedging, supply information, information acquisition.

Cronyism in Business, Public Sector and Politics

This paper contrasts the incentives for cronyism in business, the public sector and politics within an agency problem model with moral hazard. The analysis is focused on the institutional differences between private, public and political organizations. In business, when facing a residual claimant contract, a chief manager ends up with a relatively moderate …rst-best level of cronyism within a …firm. The institutional framework of the public sector does not allow explicit contracting, which leads to a more severe cronyism problem within public organizations. Finally, it is shown that the nature of political appointments (such that the subordinate's reappointment is conditioned on the chief's re-election) together with implicit contracting makes political cronyism the most extreme case. JEL classifi…cation: D72, D73, D86. Keywords: Cronyism; Meritocracy; Manager; Bureaucrat; Politician.

How much risk is mitigated by LTC Insurance? A case study of the public system in Spain

We present a methodology that allows to calculate the impact of a given Long-Term Care (LTC) insurance protection system on the risk of incurring extremely large individual lifetime costs. Our proposed methodology is illustrated with a case study. According to our risk measure, the current Spanish public LTC system mitigates individual risk by more than 30% compared to the situation where no public protection were available. We show that our method can be used to compare risk reduction of alternative LTC insurance plans.

The link between public support and private R&D effort: What is the optimal subsidy?

The effectiveness of R&D subsidies can vary substantially depending on their characteristics. Specifically, the amount and intensity of such subsidies are crucial issues in the design of public schemes supporting private R&D. Public agencies determine the intensities of R&D subsidies for firms in line with their eligibility criteria, although assessing the effects of R&D projects accurately is far from straightforward. The main aim of this paper is to examine whether there is an optimal intensity for R&D subsidies through an analysis of their impact on private R&D effort. We examine the decisions of a public agency to grant subsidies taking into account not only the characteristics of the firms but also, as few previous studies have done to date, those of the R&D projects. In determining the optimal subsidy we use both parametric and nonparametric techniques. The results show a non-linear relationship between the percentage of subsidy received and the firms’ R&D effort. These results have implications for technology policy, particularly for the design of R&D subsidies that ensure enhanced effectiveness.

Haar wavelets-based approach for quantifying credit portfolio losses

This paper proposes a new methodology to compute Value at Risk (VaR) for quantifying losses in credit portfolios. We approximate the cumulative distribution of the loss function by a finite combination of Haar wavelet basis functions and calculate the coefficients of the approximation by inverting its Laplace transform. The Wavelet Approximation (WA) method is specially suitable for non-smooth distributions, often arising in small or concentrated portfolios, when the hypothesis of the Basel II formulas are violated. To test the methodology we consider the Vasicek one-factor portfolio credit loss model as our model framework. WA is an accurate, robust and fast method, allowing to estimate VaR much more quickly than with a Monte Carlo (MC) method at the same level of accuracy and reliability.

Credit risk contributions under the Vasicek one-factor model: a fast wavelet expansion approximation

To measure the contribution of individual transactions inside the total risk of a credit portfolio is a major issue in financial institutions. VaR Contributions (VaRC) and Expected Shortfall Contributions (ESC) have become two popular ways of quantifying the risks. However, the usual Monte Carlo (MC) approach is known to be a very time consuming method for computing these risk contributions. In this paper we consider the Wavelet Approximation (WA) method for Value at Risk (VaR) computation presented in [Mas10] in order to calculate the Expected Shortfall (ES) and the risk contributions under the Vasicek one-factor model framework. We decompose the VaR and the ES as a sum of sensitivities representing the marginal impact on the total portfolio risk. Moreover, we present technical improvements in the Wavelet Approximation (WA) that considerably reduce the computational effort in the approximation while, at the same time, the accuracy increases.

Public Monitoring with Uncertainty in the Time Repetitions

This paper study repeated games where the time repetitions of the stage game are not known or controlled by the players. We call this feature random monitoring. Kawamori's (2004) shows that perfect random monitoring is always better than the canonical case. Surprisingly, when the monitoring is public, the result is less clear-cut and does not generalize in a straightforward way. Unless the public signals are sufficiently informative about player's actions and/or players are patient enough. In addition to a discount effect, that tends to consistently favor the provision of incentives, we found an information effect, associated with the time uncertainty on the distribution of public signals. Whether payoff improvements are or not possible, depends crucially on the direction and strength of these effects. JEL: C73, D82, D86. KEYWORDS: Repeated Games, Frequent Monitoring, Random Public Monitoring, Moral Hazard, Stochastic Processes.

Abortion in public reason

What abortion laws a liberal political community ought to have? Much has been said about the moral problem of abortion, but there has not been yet (to my knowledge) a fully articulate account of the bearing of the competing answers to this ethical problem on liberal public reason. The first part of my project consists in a critical review of the different attempts to solve the various philosophical puzzles, both metaphysical and moral, posed by the abortion problem. Why is it wrong to kill beings like you and me? By answering this question we shall gain a better insight into those properties we have that give us such strong reasons against killing beings like us. Here we face a tremendous philosophical diffuculty, for it is not possible to determine what the robustest account of the wrongness of killing is without dealing with deeper metaethical and metaphysical problems. Indeed, consequentialist and nonconsequentialist moral theories differ in what it is that makes an action morally wrong -is it just the outcome of the action as compared with the outcomes of its alternatives? Or is it something else? Also, what are we essentially? Is the foetus merely our precursor? Then killing a foetus is relevantly similar to contraception. Or is the foetus one of us? If so, when we kill it, are we depriving it of a future as valuable as ours? Perhaps the relation of identity (the fact that it is its future as opposed to someone else's) doesn't matter. That may be because the foetus is an aggregate of biological and psychological facts and perhaps aggregates are not substances. Or maybe it is a substance but only psychological realtions matter, not personal identity. The second part of my project has to do with the different status these metaphisical and ethical positions ought to have in liberal public reason. Though this is the part in which most research is still needed, my own intuition is that, given the depth of the philosphical views in competition, restrictive abortion laws ought to be considered unrespectful to citizens' autonomy.

Credit consulting : anàlisi de l'amortització anticipada de crèdits mitjançant el VAD

El projecte que he dut a terme és la implementació d'una pàgina web orientada a aquells usuaris que necessiten assessorament davant d'un crèdit bancari que ja posseeixen o que vulguin realitzar. Aquesta web financera té com a objectiu donar un cop de mà a tota aquella gent que té demanat un crèdit bancari a interès fixe i vol saber en un moment determinat si és convenient o no amortitzar anticipadament tenint en compte variables com: interès del mercat, penalització deguda a l'anticipació, la fiscalitat en el cas de les empreses, anys que queden per acabar de pagar el crèdit, sistema d'amortització financera utilitzat, etc.

Neither Private nor Public: The Effects of Communal Provision of Water on Child Health in Peru

The literature on local services has focused on the effects of privatization and, if anything, has compared the effects of private and mixed public-private systems versus public provision. However, alternative forms of provision such as cooperatives, which can be very prevalent in many developing countries, have been completely ignored. In this paper, we investigate the effects of communal water provison (Comités Vecinales and Juntas Administrativas de Servicios de Saneamiento) on child health in Peru. Using detailed survey data at the household- and child-level for the years 2006-2010, we exploit the cross-section variability to assess the differential impact of this form of provision. Despite controlling for a wide range of household and local characteristics, the municipalities served by communal organizations are more likely to have poorer health indicators, what would result in a downward bias on the absolute magnitude of the effect of cooperatives. We rely on an instrumental variable strategy to deal with this potential endogeneity problem, and use the personnel resources and the administrative urban/rural classi fication of the municipalities as instruments for the provision type. The results show a negative and signi cant effect of comunal water provision on diarrhea among under- five year old children. Keywords: water utilities, cooperatives, child health, regulation, Peru. JEL Classi fication Numbers: L33; L50; L95

Creació d'un sistema de gestió d'averies en un Sistema d'Informació Geográfica de distribució d'aigües creat amb Geomedia Public Works

L'objectiu d'aquest document serà el de desenvolupar, progressivament des dels aspectes genèrics fins el detall, la realització pràctica requerida a l'elaboració del SIG.