AscInd {NetIndices}R Documentation

Ascendency network indices

Description

Calculates measures of system growth and development: Ascendency, Overhead and Capacity for several (sub)networks

Usage

AscInd(Flow=NULL, Tij=t(Flow), Import=NULL, 
  Export=NULL, Dissipation=NULL)

Arguments

Flow Network matrix with Flow[i,j] the flow from i (row) to j (column); component positions in rows and columns must be the same; if present, rownames or columnnames denote the compartment names
Tij Network matrix where connectance is from column j to row i; component positions in rows and columns must be the same ; if present, rownames or columnnames denote the compartment names
Import Vector with either the *indices* or the *names* of external compartmens from where flow enters the network; the indices point to the column positions in Tij (and the row positions in Flow)
Export Vector with either the *indices* or the *names* of external compartmens to where flow leaves the network; the indices point to the row positions in Tij (and the column positions in Flow)
Dissipation Vector with either the *indices* or the *names* to external compartments that dissipate flows (e.g. respiration); the indices point to the row positions in Tij (and the column positions in Flow)

Details

The mathematical formulation of these indices can be found in the package vignette - vignette("NetIndices").

The PDF can be found in the subdirectory ‘doc’ of the NetIndices package

Value

A matrix with ascendency values (columns) for several subnetworks (rows).
The subnetworks (rows) are:

total network
internal network (excluding flows from and to external)
import flows
export flows; this includes the usuable and unusable flows (i.e. +dissipation)
dissipation flows
asc the ascendency of the network, a measure of growth and development
overh the overhead of the network
cap the development capacity of the network, an upper bound on ascendency
ACratio the ratio of ascendency and capacity

Author(s)

Karline Soetaert <k.soetaert@nioo.knaw.nl>, Julius Kipyegon Kones<jkones@uonbi.ac.ke>

References

Latham LG. 2006. Network flow analysis algorithms. Ecological Modelling 192: 586-600.
Ulanowicz RE. 2000. Ascendency: a measure of ecosystem performacne. Jorgensen SE, Muller F, editors. Handbook of Ecosystem Theories and Management. Lewis Publishers, Boca Raton, p303-315.
Ulanowicz RE, Norden JS. 1990. Symmetrical overhead in flow networks. International Journal of System Science 21: 429-437.

Examples

# The takapoto atoll network
AscInd(Takapoto,Import ="CO2",
       Export=c("CO2","Sedimentation","Grazing"),
       Dissipation="CO2")
       
# Conesprings is the example set 1a from Latham 2006.
as.data.frame(AscInd(Tij=Conesprings,Import="Inflows",
    Export=c("Export","Dissipation"),Dissipation="Dissipation"))

[Package NetIndices version 1.2 Index]