Let ξ1,ξ2,… be an iid sequence with negative mean. The (m,n)-segment is the subsequence ξm+1,…,ξn and its score is given by max{∑m+1nξi,0}. Let Rn be the largest score of any segment ending at time n, Rn∗ the largest score of any segment in the sequence ξ1,…,ξn, and Ox the...

Purpose – Turvey (2007, Physica A) introduced a scaled variance ratio procedure for testing the random walk hypothesis (RWH) for financial time series by estimating Hurst coefficients for a fractional Brownian motion model of asset prices. The purpose of this paper is to extend his work by...

In this document we use the Expectations Survey conducted monthly by the Central Bank of Colombia during the period of October 2003 - August 2012. We find that exchange rate revaluations were generally followed by expectations of further revaluation in the short run (1 month), but by...

This book gives an authoritative overview of the literature on non-stationarity, integration and unit roots, providing direction and guidance. It also provides detailed examples to show how the techniques can be applied in practical situations and the pitfalls to avoid.