This paper demonstrates two advantages of well-known block variants of standard algorithms for solving nonlinear systems. First, if a problem is suf­ficiently close to block-diagonal, block algorithms may offer significant speed advantages on a single processor. Second, block Jacobi algorithms...

Textbook approaches to forming asymptotically justified confidence intervals for the spectrum under very general assumptions were developed by the mid-1970s. This paper shows that under the textbook assumptions, the true confidence level for these intervals does not converge to the asymptotic...

Many authors have investigated the possibility of long memory in asset returns. Generally, very little evidence has been found for long memory in either stock returns or exchange rate returns. This paper applies the log-periodogram regression to a wide range of emerging market stock returns and...

We investigate the power and size performance of unit root tests when the true data generating process undergoes Markov regime-switching. All tests, including those robust to a single break in trend growth rate, have very low power against a process with a Markov-switching trend growth rate as...

This paper considers the statistical and econometric effect that fixed n-period phase-averaging has on time series generated by some simple dynamic processes. We focus on the variance and autocorrelation of the data series and of the disturbance term for levels and difference equations involving...

Many recent papers have used semiparametric methods, especially the log-periodogram regression, to detect and estimate long memory in the volatility of asset returns. In these papers, the volatility is proxied by measures such as squared, log-squared and absolute returns. While the evidence for...

In this paper the class of admissable tests for unit roots in panel data sets of autoregressive, Gaussian time series will be partially characterized. Using this characterization, several recently suggested tests are shown to be inadmissable. Since the sufficient statistic for this testing...