In credit risk modelling, the correlation of unobservable asset returns is a crucial component for the measurement of portfolio risk. In this paper, we estimate asset correlations from monthly time series of Moody’s KMV asset values for around 2,000 European firms from 1996 to 2004. We compare correlation and value-atrisk (VaR) estimates in a one–factor or market model and a multi-factor or sec...

Over the last half of the twentieth century, a number of purely empirical and mechanismbased correlations have been developed for pool nucleate boiling. Empirical correlations differ from each other substantially with respect to the functional dependence of heat flux on fluid and surface properties, including gravity. The mechanism-based correlations require knowledge of the number density of a...

In SAC 2010, Sepehrdad, Vaudenay and Vuagnoux have reported some empirical biases between the secret key, the internal state variables and the keystream bytes of RC4, by searching over a space of all linear correlations between the quantities involved. In this paper, for the first time, we give theoretical proofs for all such significant empirical biases. Our analysis not only builds a framewor...

In semi-supervised learning on graphs, response variables observed at one node are used to estimate missing values at other nodes. The methods exploit correlations between nearby nodes in the graph. In this paper we prove that many such proposals are equivalent to kriging predictors based on a fixed covariance matrix driven by the link structure of the graph. We then propose a data-driven estim...

In semi-supervised learning on graphs, response variables observed at one node are used to estimate missing values at other nodes. The methods exploit correlations between nearby nodes in the graph. In this paper we prove that many such proposals are equivalent to kriging predictors based on a covariance matrix driven by the link structure of the graph. We then propose a data-driven estimator o...

A major issue in nancial economics is the behaviour of stock returns over long horizons. This study provides empirical evidence of the long-range behaviour of various speculative returns. Using di erent techniques such as R=S and modi ed R=S analysis, detrended uctuation analysis (DFA), fractional di erencing test (GPH) and ARFIMA maximum likelihood estimation, we nd little evidence of long mem...

Geomechanical studies are very important in the development stages of oil fields to solve many problems such as wellbore instability and sand production. However, this study is not complete without availability mechanical properties rocks. These estimate from petrophysical logs based on compressional shear wave velocities. But often missing most wells, reason might be cost-saving. Therefore, ai...