The linear theory of oscillations traditionally operates with frequency representa tions based on the concepts of a transfer function and a frequency response. The universality of the critria of Nyquist and Mikhailov and the simplicity and obvi ousness of the application of frequency and amplitude - frequency characteristics in analysing forced linear oscillations greatly encouraged the development of practi cally important nonlinear theories based on various forms of the harmonic balance hypothesis . Therefore mathematically rigorous frequency methods of investi gating nonlinear systems, which appeared in the 60s, also began to influence many areas of nonlinear theory of oscillations. First in this sphere of influence was a wide range of problems connected with multidimensional analogues of the famous van der Pol equation describing auto oscillations of generators of various radiotechnical devices. Such analogues have as a rule a unique unstable stationary point in the phase space and are Levinson dis sipative. One of the pioneering works in this field, which started the investigation of a three-dimensional analogue of the van der Pol equation, was K. O. Friedrichs's paper . The author suggested a scheme for constructing a positively invariant set homeomorphic to a torus, by means of which the existence of non-trivial periodic solutions was established. That scheme was then developed and improved for dif ferent classes of multidimensional dynamical systems [131, 132, 297, 317, 334, 357, 358]. The method of Poincare mapping [12, 13, 17] in piecewise linear systems was another intensively developed direction.
Tailored especially for the working health professional, Radio Frequency and ELF Electrogmagnetic Energies is a practical guide to understanding, evaluating, and controlling the human health effects of radio-frequency (RF) and extremely low frequency (ELF) electromagnetic fields. Providing a perfect blend of applied information and theory, you'll find all you need to know about radiation safety, from the basic physics to how to set up a safety program. This book brings you cutting-edge discussions of exposure limits, monitoring instrumentation, new measurements required by human exposure standards, induced currents and contact currents, and the latest data on biological effects.
Due to the explosive global growth in the number of mobile subscribers, as well as the growth predicted in the mobile data segment, the need for improved spectrum efficiency on the radio interface becomes more and more important. Frequency hopping (FH) is an effective method for improving the spectrum efficiency. One of the advantages of FH is that it can be combined with other spectral efficiency improving features like power control, handover and reuse partitioning.
Clinical Radiology of the Horse is the best-selling, practical guide to all areas of equine radiography and radiology written by an experienced group of clinicians with a broad range of backgrounds.
Floods constitute a persistent and serious problem throughout the United States and many other parts of the world. They are responsible for losses amounting to billions of dollars and scores of deaths annually. Virtually all parts of the nation--coastal, moun- tainous and rural--are affected by them. Two aspects of the problem of flooding that have long been topics of scientific inquiry are flood frequency and risk analyses. Many new, even improved, tech- niques have recently been developed for performing these analyses. Nevertheless, actual experience points out that the frequency of say a 100-year flood, in lieu of being encountered on the average once in one hundred years, may be as little as once in 25 years. It is there- fore appropriate to pause and ask where we are, where we are going and where we ought to be going with regard to the technology of flood frequency and risk analyses. One way to address these questions is to provide a forum where people from all quarters of the world can assemble, discuss and share their experience and expertise pertaining to flood frequency and risk analyses. This is what constituted the motivation for organizing the International Symposium on Flood Frequency and Risk Analyses held May 14-17, 1986, at Louisiana State University, Baton Rouge, Louisiana.