Network calculations and ascendency based on eco-exergy |
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Authors: | Sven Erik Jørgensen Robert Ulanowicz |
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Institution: | 1. Copenhagen University, University Park 2, Institute A, Section of Environmental Chemistry, 2100 Copenhagen Ø, Denmark;2. University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Solomons, MD 20688-0038, USA |
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Abstract: | Ascendency is an index of activity and organization in living systems calculated in terms of flows. The concern here is with how that quantity behaves when the flows in question are measured in terms of eco-exergy. The storage of eco-exergy has served as a goal function in assessing parameter values for structurally dynamic models, but network magnitudes and topologies can change in response to significant changes in the forcing functions. As storages are relatively insensitive to such changes, it is advisable in such cases to explore how changes in a flow variable, like ascendency, might capture network adaptations. It happens that changes in ascendency calculated in terms of flows of simple energy are small in comparison to corresponding variations in the storages of eco-exergy. But when ascendency is reckoned in terms of flows of eco-exergy, its changes in response to network changes are more comparable to those in the storages. Ascendency seems to be more sensitive to changes in flow topology, however, so that a combination of eco-exergy storage and eco-exergy ascendency would probably be most appropriate for situations where changes in flow topology are significant. |
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Keywords: | Ascendency Eco-exergy Eco-exergy storage Networks Information Kullbach's measure of information |
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