musings on metrics for service systems
TRANSCRIPT
Chaisson, Cosmic Evolution,
Harvard Univ Press, 2001
Cosmic Evolution’s Basic Premise
• 2nd Law of Thermodynamics, Entropy, Free energy (available to do work)
• Systems with “dynamic steady state” are far from thermodynamic
equilibrium
• Systems feed off energy flow
• More complex systems require larger energy flow
• Chaisson’s primary metric is “free energy rate density”
lake
river
total energyentropy
free energy
dam
system
Hidden Assumption
≠?
• Evolved systems are likely relatively efficient
• Are (new) man-made service systems equally efficient ?
Actual
Energy
Minimal
EnergyComplexity
inefficient ?
measure
Actual
Energy
Minimal
EnergyComplexity
efficient
≈
measure
proportionalEvolved
Systems
Human
Systems
assumed proportional
assumed proportional
Free Energy Rate Density
Measurements
System Energy Flow Mass erg/sec/g
civilization (society) 18 trillion watts 6 billion
inhabitants
500,000
animal (human body) 2800 kcal/day =
1.36E9 erg/sec
70 kg =
70,000 g
20,000
star (Sun) luminosity=
4E33 erg/sec
mass=
2E33 g
2
Free Energy Rate Density
Measurements
System erg/sec/g
society (modern culture) 500,000
brain (human cranium) 150,000
animal (human body) 20,000
plant (biosphere) 900
planet (Earth) 75
star (Sun) 2
galaxy (Milky Way) 0.5
Free Energy Rate Density
for Service Systems
System erg/sec/g
society (modern culture) 500,000
United States Government ?
Hilton Hotel (chain) ?
McDonalds (chain) ?
sports complex ?
single site restaurant ?
Salvation Army ?
Boy Scouts ?
single family household ?
others ?
brains (human cranium) 150,000
animals (human body) 20,000
Service Metric Possibilitiesdriver rate density
free energy per second per gram
information
information (entropy)
bits of client insight
service hours of op
consumer hours of op
total service knowledge (bits)
size of data stores
value
service’s utility
client’s utility
money
revenue
after-tax revenue
book/liquidation value
market value
Ph
ysic
al
Info
rma
tio
na
lF
ina
nci
al
Va
lue
Related Works
• Prigogine, From Being to Becoming: Time and Complexity in the Physical Sciences, Freeman, 1980.
– Winner of 1977 Nobel Prize in Chemistry
– discusses dissipative structures and their role in thermodynamic systems far from equilibrium
– how systems far from equilibrium evolve elaborate structures
• Tainter, The Collapse of Complex Societies, Cambridge, 2013. – “Human societies and political organizations, like all living systems, are
maintained by a continuous flow of energy”
– “diminishing returns … are a recurrent aspect of sociopolitical evolution, and of investment in complexity”
– “the increased costs of sociopolitical evolution frequently reach a point of diminishing marginal returns”
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