A new complexity measure for time series analysis and classification

Complexity measures are used in a number of applications including extraction of information from data such as ecological time series, detection of non-random structure in biomedical signals, testing of random number generators, language recognition and authorship attribution etc. Different complexity measures proposed in the literature like Shannon entropy, Relative entropy, Lempel-Ziv, Kolmogrov and Algorithmic complexity are mostly ineffective in analyzing short sequences that are further corrupted with noise. To address this problem, we propose a new complexity measure ETC and define it as the “Effort To Compress” the input sequence by a lossless compression algorithm. Here, we employ the lossless compression algorithm known as Non-Sequential Recursive Pair Substitution (NSRPS) and define ETC as the number of iterations needed for NSRPS to transform the input sequence to a constant sequence. We demonstrate the utility of ETC in two applications. ETC is shown to have better correlation with Lyapunov exponent than Shannon entropy even with relatively short and noisy time series. The measure also has a greater rate of success in automatic identification and classification of short noisy sequences, compared to entropy and a popular measure based on Lempel-Ziv compression (implemented by Gzip).     

Incompressibility of strange matter

Strange stars (ReSS) calculated from a realistic equation of state (EOS), that incorporate chiral symmetry restoration as well as deconfinement at high density [Phys. Lett. B 438 (1998) 123; Phys. Lett. B 447 (1999) 352, Addendum; Phys. Lett. B 467 (1999) 303, Erratum; Indian J. Phys. B 73 (1999) 377] show compact objects in the mass radius curve. We compare our calculations of incompressibility for this EOS with that of nuclear matter. One of the nuclear matter EOS has a continuous transition to ud-matter at about five times normal density. Another nuclear matter EOS incorporates density dependent coupling constants. From a look at the consequent velocity of sound, it is found that the transition to ud-matter seems necessary.     

Spectroscopic study of a representative polar cap of buckminsterfullerene: Cyclopentacorannulene

The spectroscopic properties of corannulene and cyclopentacorannulene are examined by use of absorption and steady-state fluorescence measurements. A red shift in the emission maxima of cyclopentacorannulene is noted with respect to the emission maxima in the corannulene spectrum. Similar differences in the absorption spectra of both molecules are also observed. Reasons for the dissimilarities in the absorption and emission spectra of these molecules are discussed. The fluorescence quantum yields and lifetimes of the molecules measured in organic solvents are reported. The fluorescence quantum yield and lifetime of cyclopentacorannulene are lower than those of corannulene. This difference is attributed to the highly strained and nonplanar structure of cyclopentacorannulene. The effectiveness of nitromethane as a quencher of corannulene and cyclopentacorannulene fluorescence is examined. In contrast to previously reported results, the fluorescence of these molecules is quenched by nitromethane. Fluorescence quenching of the molecules has been attributed to complex formation in the ground state, i.e., static quenching.     

Spectroscopy of two coincident charged particles emitted following bound pion absorption in 12C, 59Co and 197Au

Energy spectra and angular distributions of two coincident charged particles emitted following stopped negative pion absorption in ¹²C, ⁵⁹Co and ¹⁹⁷Au were measured. Most of the data can be understood within the framework of a pair absorption model including final-state interactions. Ground-state transitions in the missing mass spectra of ⁴H and ⁴He deduced from the αα and tα spectra of ¹²C, respectively, show that reactions involving a large part of the nucleus also occur.     

Electrophoretic study of alpha-D-galactosidases from seeds of Glycine soja and Vigna radiata possessing erythroagglutinating activity

Polyacrylamide gel electrophoresis in an acidic buffer system was used to study the electrophoretic behaviour of two forms of alpha-D-galactosidase from seeds of soy bean (Glycine soja) and mung bean (Vigna radiata). The interaction of the enzymes with saccharides was monitored by affinity electrophoresis; for the preparation of affinity gels, water-soluble O-glycosyl polyacrylamide copolymers and polysaccharides were used. alpha-D-Galactosidases from both sources interact with immobilized alpha-D-galactosyl residues. On the basis of the results of affinity electrophoresis performed in the presence of various free sugars, dissociation constants for the complexes between alpha-D-galactosidase and free sugars were calculated.     

Single-photon exchange quasi-potentials ofN-particle systems

The covariant single-time approach of quantum field theory and perturbation theory are used to construct an explicit form of the electromagnetic interaction operator for mixedN-particle systems consisting of spinor and scalar particles. F. Skoriny State University, Gomelsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 13–25, September, 1997.     

On construction and uses of balancedn-ary designs

Summary Methods of construction of balancedn-ary designs using difference sets have been studied in this paper. Some properties of balancedn-ary designs are studied. Use of balanced ternary designs has been made to construct some efficient weighing designs. Institute of Agricultural Research Statistics     

A novel study of charged carbon clusters using a tandem Van de Graaff accelerator

A conventional tandem Van de Graaff accelerator is used to produce charged carbon cluster beams. The unique capability of the method for studying highly charged clusters unaccessible to other methods of producing cluster beams is demonstrated.