Boundary Element-Image Method Approach to Seismic Modeling

The Boundary Element-Image Method is Proposed as a Method for Generating Synthetic Seismograms in a System of Piecewise Homogeneous Layers. the Present Approach Uses the Boundary Conditions Explicitly in Order to Develop a System of Integral Equations. Although This Method Can Be Formulated in a General Way, Specific Computational Advantages Occur When the Basis and Testing Functions Are Chosen as Harmonically Related Complex Sinusoids. -From Author

Improved Wavenumber Resolution for Small Arrays

The Objective of the Method Described is to Compute the Fourier Transform of a Function of Space and Time with a Significant Improvement in the Resolution of Spatial Frequencies, particularly in the Case of Small Arrays for Which the Size of the Array is on the Order of One Wavelength (Or less). This Improvement is Initially Developed by Considering the Conversion of Spatial Frequency into Temporal Frequency through the Oscillatory Motion of a Single Receiver. a More Practical Scheme is Next Presented in Which the Oscillatory Motion is Created Synthetically by the Appropriate Sequential Sampling of Individual Elements in a Receiving Array. Both Forms of This Method (Real and Synthetic Motion) Besides Providing Some Degree of Super-Resolution Are Linear and Indicative of Amplitude as Well as Phase. Copyright © 1983 by the Institute of Electrical and Electronics Engineers, Inc

The Effective Autocorrelation Function of Maximum Entropy Spectra

The technique and the relative advantages of maximum entropy spectrum analysis have been discussed by Burg [1], [2]. Evaluation of the inverse Fourier transform of the maximum entropy spectrum shows that this method does, indeed, correspond to a reasonable nonzero extension of the autocorrelation function

FOURIER TRANSFORMS over WARPED DOMAINS.

The Author Shows that There May Be an Advantage to Computing Fourier Transforms Over Warped Domains. an Example of Such an Improvement is Provided. It is Also Shown How the Fourier Transform May Be Evaluated from Data Observed over a Warped Domain

The Estate Tax Marital Deduction

The estate tax marital deduction, section 2056 of the Internal Revenue Code, was enacted in 1948, along with the split-income provisions of the income tax law and the marital deduction and split-gift provisions of the gift tax law. The purpose was to give married residents of common law states approximately the same federal tax advantages that were available to married residents of community property states. Ordinarily, upon the death of a married resident of a community property state, only one-half of the community property is taxed in the decedent\u27s estate. Section 2056 achieves approximately the same result for married residents of common law states by providing a deduction - limited, in general, to the greater of $250,000 or one-half of the estate - for the value of property interests included in the decdent\u27s gross estate that pass from the decedent to the surviving spouse

A very high frequency radio interferometer for investigating ionospheric disturbances using geostationary satellites. Determination of changes in exospheric electron content by a comparison of group delay and Faraday rotation

The theory and development of a VHF correlation radio interferometer for investigating ionospheric disturbances are discussed. The system was developed to receive signals from the geostationary Applications Technology Satellites. Amplitude and phase variations of the signal passing through the ionosphere can be detected by this instrument. The system consists of two superheterodyne receivers separated by a distance known as the baseline of the system. Since the system is a phase sensitive instrument, the local oscillators of the two receivers must be phase coherent. This is accomplished by using phase-locked loops for generating the local oscillators. The two signals from the separate receivers are cross-correlated by multiplying the two signals together and then time averaging the result. The sensitivity of the instrument is increased by off-setting one of the local oscillators by a small amount