IDET =
(5)
A more elaborate measure is the Yan and Ames (1963) interrelatedness measure (M6 -
YAAM), defined as:
11
yaam = ʒ ∑ OA (6)
n i , j Oij
where OYijA is the Order Matrix, with each entry representing the smallest order of
interrelatedness between i and j, i.e. given the series A, A2, A3, ..., Ak, and with k consisting
of the exponent necessary to convert the corresponding cell to nonzero.
Dietzenbacher (1992) proposed as an alternative measure of connectedness the Dominant
Eigenvalue of Matrix A (M7 - DEVA):
DEVA = λ (7)
with λ being the dominant eigenvalue of matrix A. This measure was recently used and
refined by Midmore et al. (2006).
Of particular importance for the study of ecological systems are the following measures
of connectedness proposed by Finn (1976) and Ulanovics (1983): the Mean Path Length and
the Cycling Index.
The Mean Path Length (M8 - MPLE) is:
i Xi
MPLE = — (8)
i'y