In direct spread CDMA systems, codebooks meeting the Welch bounds are used to distinguish among the signals of different users. Recently, constructions of codebooks with difference sets meeting Welch’s bound on the maximum cross-correlation amplitude were developed. In this paper, a generic construction of codebooks using almost difference sets is considered and several classes of codebooks nea...

Many new binary sequences are obtained from Jacobi sequences with arbitrary starting points and investigated from the cryptographic viewpoint. Autocorrelation values of these new sequences and cross-correlation values between of them are calculated. The results show that these values may be very low and distributed flatly under certain conditions. Linear complexity of them can be proved always ...

S U M M A R Y The Green’s function that describes wave propagation between two receivers can be reconstructed by cross-correlation provided that the receivers are surrounded by sources on a closed surface. This technique is referred to as ‘interferometry’ in exploration seismology. The same technique for Green’s function extraction can be applied to the solution of the diffusion equation if the...

For the wave equation, the Green’s function that describes the wave propagating between two receivers can be reconstructed by cross-correlation if the receivers are enclosed by sources on a closed surface. This technique is normally called interferometry. The ordinary operator used in this technique is cross-correlation. The same technique for Green’s function extraction can be applied to the s...

This paper proposes new methods for the econometric analysis of outlier contaminated multivariate conditionally heteroscedastic time series. Robust alternatives to the Gaussian quasi-maximum likelihood estimator are presented. Under elliptical symmetry of the innovation vector, consistency results for M-estimation of the general conditional heteroscedasticity model are obtained. We also propose...

A combination of borehole Stoneley waves from full waveform acoustic logs and direct shear wave logs was used to estimate formation permeability and shear wave velocity. Data sets used here were collected by ARea's array full waveform acoustic logging tool and shear wave logging tool. The Pand S-wave velocities of the formation are determined by threshold detection with cross-correlation correc...

An iterative algorithm that reconstructs the attenuation map and emission activity distribution from SPECT emission data is proposed. The algorithm is based on the quasilinearized attenuated Radon transform. At each iteration of the algorithm, emission activity distribution is reconstructed using the attenuation map from the previous iteration. Then, the attenuation map is estimated by using th...

We discuss a simple methodology to enable a statistical comparison of human population with the vegetation of North America over the past 13000 years. Nonparametric kernel methods are applied for temporal and spatial smoothing of point data obtained from the Neotoma Paleoecology Database and the Canadian Archaeological Radiocarbon Database, which results in sequences of maps showing the develop...