It has been suggested that existing estimates of the long-run impact of a surprise move in income may have a substantial upward bias due to the presence of a trend break in 1970s (1350s) and 1980s (1360s) gross domestic product (contained oil) data of Iran. This article shows that the statistical evidence does not warrant abandoning the no-trend-break null hypothesis at the 5% significance leve...

abstract: enviromental concerns, improvements in renewable energy technologies, governmental incentives for the use of these resources, and increased t&d; costs, are the main factors driving the energy sector into a new era, where considerable portions of electrical demand will be met through widespread installation of distributed energy resources (ders). the virtual power plant (vpp) is a dece...

While there is good reason to expect crude oil production to be non-linear, previous studies that have examined the stochastic properties of crude oil production have assumed that crude oil production follows a linear process. If crude oil production is a non-linear process, conventional unit root tests, which assume linear and systematic adjustment, could interpret departure from linearity as ...

A time series with a unit root or fractional unit root can be miscategorized in stationarity tests if the series has structural breaks. This finding is tested on Finnish and Swedish party popularity series. The composition and nature of popularity series provide reasons to assume fractional dynamics. The years included, 1987-2001, offer several reasons for the existence of structural breaks. Th...

It is well known that some XML elements correspond to objects (in the sense of object-orientation) and others do not. The question we consider in this paper is what benefits we can derive from paying attention to such object semantics, particularly for the problem of keyword queries. Keyword queries against XML data have been studied extensively in recent years, with several lowest-common-ances...

Let p be a prime. We prove that if a modular unit has a pth root that is again a modular unit, then the level of that root is at most p times the level of the original unit.