? Ochiai coefficient ?

• To: mdsm@gpsrv1.gpsr.colostate.edu
• Subject: ? Ochiai coefficient ?
• From: Tugjayzhab Bai <jbai@lamar.ColoState.EDU>
• Date: Sun, 19 Jan 1997 22:02:40 -0700 (MST)
• Cc: jbai@lamar.ColoState.EDU (Tugjayzhab Bai), sino-ecol@biomod.fw.vt.edu, STATSOC-L@mhc.mtholyoke.edu

Is there any body knows anything about "Ochiai Coefficient"?

Dear friends, 

I used to think that cosine value as a similarity coefficient was
mentioned in "Multivariate Analysis in Community Ecology" (Gauch,
1982, Cambridge), and discussed and applied in vegetation
classification in "Exploration of Numerical Classification of Form
Leymus Chinensis ..." (Bai, 1982, University of Inner Mongolia ).
However, recently, when I was reading "Data Analysis in Community and
Landscape Ecology" (Jongman et. al., 1995, Cambridge), I found that
the cosine was named as "Ochiai coefficient". However, I could not
find related reference in the book. 

Is there anybody can tell me more detail about the Ochiai' work, such
as, is he a mathematician or an ecologist, is he the same person as
the editor of "Advanced Studies in Pure Mathematics 18", and when he
used cosine value as similarity of coefficient?

Thank you very much.

Jay Bai

(Jongman, et. al., 1995, page 178)--"More emphasis is given to
qualitative aspects by not considering a site as point but as a
vector.Understandably, the direction of this vector tells us something
about the relative abundances of species. The similarity of two sites
can be expressed as some function of the angle between the vector of
these sites. Quite common is the use of the cosine (or Ochiai
coefficient):
cos=OS
=sigma(k)Y(ki)Y(kj)/sqrt{[sigma(k)(y(ki)^2)][sigma(k)(Y(kj))^2)]}" 

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