Most financial markets produce inhomogeneous (i.e. unequally spaced) tick-by-tick data at high frequency. Recently developed time series operators can be used to directly compute statistical variables such as volatility from inhomogeneous data. This is not possible with traditional time series...

In the late 1980s, as the empirical appeal of macro-economic exchange rate models began to fade, a few people including Professor Charles Goodhart at the London School of Economics and researchers at Olsen & Associates in Zurich, started to collect intra-daily exchange rate data. The resulting...