By Topic

IBM Journal of Research and Development

Issue 4 • July 1989

Filter Results

Displaying Results 1 - 8 of 8
  • Modeling and image processing for visualization of volcanic mapping

    Publication Year: 1989, Page(s):406 - 416
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1091 KB)

    In countries such as Italy, Japan, and Mexico, where active volcanoes are located in highly populated areas, the problem of risk reduction is very important. Actual knowledge about volcanic behavior does not allow deterministic event prediction or the forecasting of eruptions. However, areas exposed to eruptions can be analyzed if eruption characteristics can be inferred or assumed. Models to simu... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Natural quadrics: Projections and intersections

    Publication Year: 1989, Page(s):417 - 446
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (2004 KB)

    Geometrical modelers usually strive to support at least solids bounded by the results of Boolean operations on planes, spheres, cylinders, and cones, that is, the natural quadrics. Most often this set is treated as a subset of the set of quadric surfaces. Although the intersection of two quadrics is a mathematically tractable problem, in implementation it leads to complexity and stability problems... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Femtosecond laser studies of the relaxation dynamics of semiconductors and large molecules

    Publication Year: 1989, Page(s):447 - 455
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (758 KB)

    The use of femtosecond lasers and the related optical correlation spectroscopic technique for studying the relaxation dynamics of semiconductors and photoexcited molecules are reviewed. In particular, the results on the intraband relaxation of nonequilibrium carriers in GaAs and related compounds and quantum well structures are summarized. The optical correlation technique also led to the observat... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effects of quasiperiodic (Penrose tile) symmetry on the eigenvalues and eigenfunctions of the wave equation

    Publication Year: 1989, Page(s):456 - 463
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (660 KB)

    In addition to the basic crystalline and amorphous structures for solids, it is possible that solids may also form with a quasiperiodic, or Penrose tile, structure. A current problem in condensed-matter physics is to determine how this structure affects the various physical properties of a material. A fundamental question involves the consequences of quasiperiodic symmetry in the eigenvalue spectr... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Time series in M dimensions: The power spectrum

    Publication Year: 1989, Page(s):464 - 469
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (499 KB)

    The approach presented here extends the modeling of M-dimensional (spatial) time series from the time domain into the frequency domain. The autocovariance function for an M-dimensional time series is transformed to obtain the power spectrum in M dimensions. The latter describes the variance within the series and can be used to identify dependencies and/or test the adequacy of a fitted model. An ex... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Two-level coding for error control in magnetic disk storage products

    Publication Year: 1989, Page(s):470 - 484
    Cited by:  Papers (8)  |  Patents (4)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1164 KB)

    Error-control coding has played a significant role in the design and development of magnetic recording storage products. The trend toward higher densities and data rates presents continuing demands for an ability to operate at a lower signal-to-noise ratio and to tolerate an increased number of correctable errors. Heretofore, the magnetic disk storage products used coding schemes that provided cor... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Recent publications by IBM authors

    Publication Year: 1989, Page(s):485 - 497
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1149 KB)

    The information listed here is supplied by the Institute for Scientific Information and other outside sources. Reprints of the papers may be obtained by writing directly to the first author cited. Information on books may be obtained by writing the publisher. Papers and books are listed alphabetically by author. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Recent IBM patents

    Publication Year: 1989, Page(s):498 - 500
    IEEE is not the copyright holder of this material | PDF file iconPDF (258 KB)
    Freely Available from IEEE

Aims & Scope

Meet Our Editors

Editor-in-Chief
Clifford A. Pickover
IBM T. J. Watson Research Center