|Look up self-sustaining in Wiktionary, the free dictionary.|
A system is self-sustaining (or self-sufficient) if it can maintain itself by independent effort. The system self-sustainability is:
- the degree at which the system can sustain itself without external support
- the fraction of time in which the system is self-sustaining
Self-sustainability is considered one of the "ilities" and is closely related to sustainability and availability. In the economics literature, a system that has the quality of being self-sustaining is also referred to as an autarky.
- Let be a random variable that denotes the steady state number of external entities on which the system depends. Let be the probability that the system depends on external entities, . Then, the system self-sustainability, , is .
- Let be the expected time during which the system is self-sustaining from time 0 up to time . Then, the system self-sustainability is the steady state fraction of time in which it is self-sustaining,
Autarky exists whenever an entity can survive or continue its activities without external assistance. Autarky is not necessarily economic. For example, a military autarky would be a state that could defend itself without help from another country.
According to the Department of Labor of the state of Idaho, an employed adult shall be considered self-sufficient if the family income exceeds 200% of the Office of Management and Budget poverty income level guidelines.
In peer-to-peer swarming systems, a swarm is self-sustaining if all the blocks of its files are available among peers (excluding seeds and publishers).
Self-sustainability and survivability
Whereas self-sustainability is a quality of one’s independence, survivability applies to the future maintainability of one’s self-sustainability and indeed one’s existence. Many believe that more self-sustainability guarantees a higher degree of survivability. But just as many oppose this, arguing that it is not self-sustainability that is essential for survivability, but on the contrary specialization and thus dependence.
Consider the first two examples presented above. Among countries, commercial treats are as important as self-sustainability. An autarky is usually inefficient. Among people, social ties have been shown to be correlated to happiness and success as much as self-sustainability.
Notes and references
- IDAHO Department of Labor (1999). "Definition of Self-sufficiency." Retrieved on 2010-06-26.
- Menasche, Rocha, de Souza e Silva, Leao, Towsley, Venkataramani (2010). "Estimating self-sustainability in peer-to-peer swarming systems" Retrieved on 2010-06-26.
- What and Who is Self-Sufficient? by Katrien Vander Straeten
- on YouTube