Synthesis of a Zobel “M-Derived Half Section” and “Constant K” Filter
(A Human-Competitive Result Produced by Genetic Programming)
Genetic programming evolved a Zobel “M-derived half section” and “constant K” filter circuit as described in Section 25.15.2 of Genetic Programming III: Darwinian Invention and Problem Solving (Koza, Bennett, Andre, and Keane 1999). The “M-derived half section” in this figure is the vertical shunt containing capacitor C3 and inductor L11.
The
circuit in the figure has the recognizable features of the circuit for which
Otto Zobel of American Telephone and Telegraph received U.S. patent1,538,964
(Zobel 1925). Zobel invented the idea of adding an "M-derived half
section" to one or more "constant K" sections. As he explains in
U.S. patent 1,538,964 (Zobel 1925),
“The
principal object of my invention is to provide a new and improved network for the
purpose of transmitting electric currents having their frequency within a
certain range and attenuating currents of frequency within a different range. .
. . Another object of my invention is to provide a wave-filter with recurrent
sections not all of which are alike, and having certain advantages over a
wave-filter with all its sections alike.”
The
advantage of Zobel's approach is a "sharper transition" in the
frequency domain behavior of the filter. Claim 1 of Zobel's 1925 patent covers
“A
wave-filter having one or more half-sections of a certain kind and one or more
other half-sections that are M-types thereof, M being different from unity.”
Claim 2
covers
“A
wave-filter having its sections and half-sections so related that they comprise
different M-types of a common prototype, M having several values for
respectively different sections and half-sections.”
Claim 3
goes on to cover
“A
wave-filter having one or more half-sections of a certain kind and one or more
half-sections introduced from a different wave-filter having the same
characteristic and the same critical frequencies and a different attenuation
characteristic outside the free transmitting range.”
Viewed as
a whole, the differences between the teachings of Zobel's 1925 patent and the
evolved circuit are minor and unsubstantial. Thus, under the "doctrine of
equivalences," the evolved circuit infringes on the claims of the
now-expired Zobel patent.
Referring to the eight criteria in chapter 1 of Genetic Programming III: Darwinian Invention and Problem Solving (Koza, Bennett, Andre, and Keane 1999) for establishing that an automatically created result is competitive with a human-produced result, the automatic synthesis of the Zobel “M-derived half section” filter circuit satisfies the following two criteria:
(A) The
result was patented as an invention in the past, is an improvement over a
patented invention, or would qualify today as a patentable new invention.
(F) The
result is equal to or better than a result that was considered an achievement
in its field at the time it was first discovered.
Johnson,
Walter C. 1950. Transmission Lines and Networks. New York: McGraw-Hill.
Koza, John R., Bennett III, Forrest H, Andre, David, and Keane, Martin A. 1999a. Genetic Programming III: Darwinian Invention and Problem Solving. San Francisco, CA: Morgan Kaufmann.
Zobel, Otto
Julius. 1925. Wave Filter. U.S. Patent 1,538,964. Filed January 15,
1921. Issued May 26, 1925.
· The home page of Genetic Programming Inc. at www.genetic-programming.com.
· For information about the field of genetic programming and the field of genetic and evolutionary computation, visit www.genetic-programming.org
· The home page of John R. Koza at Genetic Programming Inc. (including online versions of most published papers) and the home page of John R. Koza at Stanford University
· For information about John Koza’s course on genetic algorithms and genetic programming at Stanford University
· Information about the 1992
book Genetic
Programming: On the Programming of Computers by Means of Natural Selection,
the 1994 book Genetic
Programming II: Automatic Discovery of Reusable Programs, the 1999
book Genetic
Programming III: Darwinian Invention and Problem Solving, and the
2003 book Genetic
Programming IV: Routine
Human-Competitive Machine Intelligence. Click here to read chapter 1 of Genetic
Programming IV book in PDF format.
· 3,440
published papers on genetic programming (as of November 28, 2003) in a
searchable bibliography (with many on-line versions of papers) by over 880
authors maintained by William Langdon’s and Steven M. Gustafson.
· For information on the Genetic Programming and Evolvable Machines journal published by Kluwer Academic Publishers
· For information on the Genetic Programming book series from Kluwer Academic Publishers, see the Call For Book Proposals
· For information about the annual Genetic and Evolutionary Computation (GECCO) conference (which includes the annual GP conference) to be held on June 26–30, 2004 (Saturday – Wednesday) in Seattle and its sponsoring organization, the International Society for Genetic and Evolutionary Computation (ISGEC). For information about the annual Euro-Genetic-Programming Conference to be held on April 5-7, 2004 (Monday – Wednesday) at the University of Coimbra in Coimbra Portugal. For information about the 2003 and 2004 Genetic Programming Theory and Practice (GPTP) workshops held at the University of Michigan in Ann Arbor. For information about Asia-Pacific Workshop on Genetic Programming (ASPGP03) held in Canberra, Australia on December 8, 2003. For information about the annual NASA/DoD Conference on Evolvable Hardware Conference (EH) to be held on June 24-26 (Thursday-Saturday), 2004 in Seattle.
Last updated on December 28, 2003