Predicting chaotic time-series with wavelet networks

A new technique, wavelet network, is introduced to predict chaotic time series. By using this technique, firstly, we make accurate short-term predictions of the time series from chaotic attractors. Secondly, we make accurate predictions of the values and bifurcation structures of the time series from dynamical systems whose parameter values are changing with time. Finally we predict chaotic attractors by making long-term predictions based on remarkably few data points, where the correlation dimensions of predicted attractors are calculated and are found to be almost identical to those of actual attractors.

Direct dynamical test for deterministic chaos and optimal embedding of a chaotic time-series

We propose here a local exponential divergence plot which is capable of providing an alternative means of characterizing a complex time series. The suggested plot defines a time-dependent exponent and a ''plus'' exponent. Based on their changes with the embedding dimension and delay time, a criterion for estimating simultaneously the minimal acceptable embedding dimension, the proper delay time, and the largest Lyapunov exponent has been obtained. When redefining the time-dependent exponent LAMBDA(k) curves on a series of shells, we have found that whether a linear envelope to the LAMBDA(k) curves exists can serve as a direct dynamical method of distinguishing chaos from noise.

Local exponential divergence plot and optimal embedding of a chaotic time-series

we propose here a local exponential divergence plot which is capable of providing a new means of characterizing chaotic time series. The suggested plot defines a time dependent exponent LAMBDA and a ''plus'' exponent LAMBDA+ which serves as a criterion for estimating simultaneously the minimal acceptable embedding dimension, the proper delay time and the largest Lyapunov exponent.

Singularity criteria for perturbation series

This paper is concerned with some mathematical aspects of the Van Dyke method inperturbation theory, i.e. the singularity criteria of perturbation series. The author suggestsa sign criterion and a Domb-syke plot for the cases with complex conjugate singularities, thussucceeding in extending the conclusions of Van Dyke's. Subsequently. effects of singularitiesof the lower order upon the criteria are taken into account. In addition, a method of locat-ing singular points is developed by analysing the new perturbation series derived by the Eulertransformation.

Series representation of the Gaussian beam far-field diffracted by annular aperture

Accurate, analytical series expressions for the far-field diffraction of it Gaussian beam normally incident on a circular and central obscured aperture are derived with the help of the integration of parts method. With this expression, the far-field intensity distribution pattern can be obtained and the divergence angle is deduced too. Using the first five items of the series, the accuracy can satisfy most laser application fields. Compared with the conventional numerical integral method, the series representation is very convenient for understanding the physical meanings. (C) 2007 Elsevier GmbH. All rights reserved.

Theoretical investigation on the one- and two-photon absorption properties for a series of symmetrical charge transfer fluorene-phenylene and fluorene-thiophene derivatives

One- and two-photon absorption properties of a series of fluorene derivatives with symmetrical charge transfer D-IT-D and A-IT-A structural motifs have been theoretically investigated with ZINDO/S method. The optimized structures and the characterization of frontier molecular orbitals were obtained by using AMI calculations. Two-photon absorption properties of molecules have been studied using three-state model. The calculation results have shown that fluorene-thiophene derivatives exhibit larger two-photon absorption cross-section as compared with other studied molecules. To illustrate the results, the crucial effects of thiophene ring on fluorenethiophene derivatives and the net charge changes on the pi-conjugated bridges are analyzed theoretically. (c) 2006 Elsevier B.V. All rights reserved.

ISOLATION AND PROPERTIES OF A BLOOD-COAGULATION FACTOR-X ACTIVATOR FROM THE VENOM OF KING COBRA (OPHIOPHAGUS HANNAH)

A specific blood coagulation factor X activator was purified from the venom of Ophiophagus hannah by gel filtration and two steps of FPLC Mono-Q column ion-exchange chromatography. It showed a single protein band both in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and alkaline polyacrylamide gel electrophoresis. The mol. wt was estimated to be 62,000 in non-reducing conditions and 64,500 in reducing conditions by SDS-PAGE. The isoelectric point was found to be pH 5.6. The enzyme had weak amidolytic activities toward CBS 65-25, but it showed no activities on S-2266, S-2302, thrombin substrate S-2238, plasmin substrate S-2251 or factor Xa substrate S-2222. It had no arginine esterase activity toward substrate benzoylarginine ethylester (BAEE). The enzyme activated factor X in vitro and the effect was absolutely Ca2+ dependent, with a Hill coefficient of 6.83. It could not activate prothrombin nor had any effect on fibrinogen and thus appeared to act specifically on factor X. The procoagulant activity of the enzyme was almost completely inhibited by serine protease inhibitors like PMSF, TPCK and soybean trypsin inhibitor; partially inhibited by L-cysteine. Metal chelator EDTA did not inhibit its procoagulant activity. These results suggest that the factor X activator from O. hannah venom is a serine protease.

Cloning and purification of alpha-neurotoxins from king cobra (Ophiophagus hannah)

Thirteen complete and three partial cDNA sequences were cloned from the constructed king cobra (Ophiophagus hannah) venom gland cDNA library. Phylogenetic analysis of nucleotide sequences of king cobra with those from other snake venoms revealed that obta

Isolation and cloning of a metalloproteinase from king cobra snake venom

A 50 kDa fibrinogenolytic protease, ohagin, from the venom of Ophiophagus hannah was isolated by a combination of gel filtration, ion-exchange and heparin affinity chromatography. Ohagin specifically degraded the alpha-chain of human fibrinogen and the pr

Molecular characterization of L-amino acid oxidase from king cobra venom

An L-amino acid oxidase from Ophiophagus hannah snake venom (Oh-LAAO) was purified by successive gel filtration, ion-exchange and heparin chromatography. Oh-LAAO did not induce platelet aggregation; however, it had potent inhibitory activity on platelet a