In this paper we investigate how in commons based peer production a large community of contributors coordinates its efforts towards the production of high quality open content. We carry out our empirical analysis at the level of articles and focus on the dynamics surrounding their production....

In the paper we investigate an organizational practice meant to increase the quality of commons-based peer production: the use of template messages in wiki collections to highlight editorial bugs and call for intervention. In the context of SimpleWiki, an online encyclopedia of the Wikipedia...

Current trends in international banking supervision following the 1996 Amendment to the Basel Accord emphasise market risk control based upon internal Value-at-risk (VaR) models. This paper discusses the merits and drawbacks of VaR models in the light of their impact on market liquidity. After a...

The aim of this paper consists in testing the profitability of simple technical trading rules in the Italian stock market. By means of a recently developed bootstrap methodology we assess whether technical rules based on moving averages are capable of producing excess returns with respect to the...

We propose a stochastic model for the probability of default based on diffusions with given marginal distribution and autocorrelation function. The model tries to capture stylized features observed in historical default rates and is analytically tractable. Estimation procedures and expressions...

This paper describes the implied volatility function computed from options on the Italian stock market index between 1995 and 1998 and tries to find out potential explanatory variables. We find that the typical smirk observed for S&P500 stock index characterizes also Mib30 stock index. When...

When young people drop out of school they are in great danger of being marginalized in society. Immigrants are another group of people who for several reasons often find it difficult to become integrated into their new home country. In both cases some less formal way of learning might help these...

Continuous non-Gaussian stationary processes of the OU-type are becoming increasingly popular given their flexibility in modelling stylized features of financial series such as asymmetry, heavy tails and jumps. The use of non-Gaussian marginal distributions makes likelihood analysis of these...

We study the structure of business firm networks in the Life Sciences (LS) and the Information and Communication Technology (ICT) sectors. We analyze business firm networks and scale-free models with degree distribution P(q) proportional to (q + c)^-λ using the method of k-shell decomposition....

The relationship between the size and the variance of firm growth rates is known to follow an approximate power-law behavior σ(S) similar to S^-β(S) where S is the firm size and β(S) almost equal to 0.2 is an exponent weakly dependent on S. Here we show how a model of proportional growth...