Reliable scaling exponent estimation of long-range correlated noise in the presence of random spikes

Detrended fluctuation analysis (DFA) has been used widely to determine possible long-range correlations in data obtained from diverse settings. In a recent study [1], uncorrelated random spikes superimposed on the long-range correlated noise (LR noise) were found to affect DFA scaling exponent estimates. In this brief communication, singular-value decomposition (SVD) filter is proposed to minimize the effect random spikes superimposed on LR noise, thus facilitating reliable estimation of the scaling exponents. The effectiveness of the proposed approach is demonstrated on random spikes sampled from normal and uniform distributions.Comment: 36 Pages, 20 Figure

Comment of Global dynamics of biological systems

In a recent study, (Grigorov, 2006) analyzed temporal gene expression profiles (Arbeitman et al., 2002) generated in a Drosophila experiment using SSA in conjunction with Monte-Carlo SSA. The author (Grigorov, 2006) makes three important claims in his article, namely: Claim1: A new method based on the theory of nonlinear time series analysis is used to capture the global dynamics of the fruit-fly cycle temporal gene expression profiles. Claim 2: Flattening of a significant part of the eigen-spectrum confirms the hypothesis about an underly-ing high-dimensional chaotic generating process. Claim 3: Monte-Carlo SSA can be used to establish whether a given time series is distinguishable from any well-defined process including deterministic chaos. In this report we present fundamental concerns with respect to the above claims (Grigorov, 2006) in a systematic manner with simple examples. The discussion provided especially discourages the choice of SSA for inferring nonlinear dynamical structure form time series obtained in any biological paradigm.Comment: 6 pages, 2 figure

Regionalism and the WTO: New Rules for the Game?

The recent growth of regional integration agreements (customs unions and free-trade areas) has been accompanied by a mounting concern for the health of the multilateral trading system. Much of this concern stems from the generally accepted view that the current WTO rules do not provide an adequate set of disciplines on regional arrangements. The EU has been one of the main driving forces behind the recent growth of regionalism, but its interests are increasingly affected by regional arrangements formed between other countries. This paper argues that the lack of clear WTO disciplines on regional arrangements may have already had adverse consequences for the EU. Given that the EU has declared its support for a clarification of the rules, the paper tries to identify where its priorities should lie. It is argued that there should be two such priorities. The first should be to define more precisely what is meant by an "applicable" tariff. It has never been clear whether this refers to applied tariff rates or to bound ceilings. Because of this ambiguity, Mexico was able to raise applied tariffs (within bound ceilings) on imports from the EU and other third countries in response to the peso crisis, whilst lowering tariffs on her NAFTA partners. Secondly, the EU and other major WTO players need to address the problem of different rules of origin emerging from the proliferation of regional arrangements.world trade organisation

Effective of Passive Devices in Alleviation of Flow-induced oscillations of he nozzles of a Multi-Booster Launch vehicle

Wind tunnel tests to quantify the flow induced oscillations of nozzles of strap-on boosters of a typical launch vehicle have been performed under jet-off conditions in the Mach number range 0.8 to 2.5. The effects of gymballing the nozzles on the steady and unsteady radial and tangential moments acting at the simulated position of gymbal actuators have been studied. The loads are seen to increase as the gymbal angle increases. The effectiveness of various load alleviating passive devices in reducing steady and unsteady loads was evaluated. The most effective device was found to be a semi-circular segment. The spectra of unsteady moments indicate that the loads alleviating devices do not significantly alter the magnitude as compared to that of the baseline data