An Engineering Guide To Spectral Analysis

An Engineering Guide to Spectral Analysis

The document is aimed at providing insight into the various aspects of spectral analysis of samples drawn from populations generally representing oceanographic and geophysical events. Hypothetical spectra, with more or less typical shapes, are developed and from these are generated a series of 'time histories'. The records are subjected to spectral analysis with systematic variation of number of points, sampling interval and number of lags. From the results of computing several hundred spectra, it is seen that estimation of the true spectrum is affected in various ways by: length of record, resolution, aliasing, spectral window and confidence bounds. Since it is impossible to specify a set of rules for every conceivable spectral density calculation, this paper shows how consideration of the elements mentioned above leads to design of the analysis experiment most likely to extract maximum reliable information from the data. In general, the work described here applies to stationary processes, but the treatment of non-stationary events is also discussed briefly. (Author).

An Engineering Guide to Spectral Analysis

Random Processes in Geology

The International Association for Mathematical Geology, in conjunc tion with the International Geological Congress, sponsored two symposia in Montreal, Canada, September 1972. The first symposium, Random Processes in Geology, consisted of two, half-day sessions and featured ten major papers on various aspects of stochastic models as applied to geologic problems. The invited speakers were selected by the Projects Committee of the IAMG so as to represent a wide spectrum of geologic disciplines. The topics fell naturally into two categories: those dealing with continuous stochastic processes and those concerned with point processes and branch ing operations. The program, as presented, was Introduction: R. A. Reyment Ideal granites and their metasomatic transformation: stochastic model, statistical description, and natural rocks: A. B. Vistelius (read by G. Lea) The influence of greisenization on the Markovian properties of grain sequences in granitic rocks: M. A. Romanova The mechanism of bed formation in a limestone-shale environment: W. Schwarzacher Volcanic eruptions as random events: F. E. Wickman Statistical geometric similarity in drainage networks: J. S. Smart Length and gradient properties of stochastic streams: M. F. Dacey Application of stochastic point processes to volcanic eruptions: R. A. Reyment Applications of random process models to the description of spatial distributions of qualitative geologic variables: P. Switzer Sedimentary porous materials as a realization of a stochastic process: F. W. Preston and J. C. Davis Stochastic process models in geology: W. C. Krumbein. This volume consists of eight of the ten presented papers.