Self-sustainability

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A system is self-sustaining (or self-sufficient) if it can maintain itself by independent effort. The system self-sustainability is:

1. the degree at which the system can sustain itself without external support
2. 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.

Video Self-sustainability

Formal definition

1. Let ${\displaystyle E}$ be a random variable that denotes the steady state number of external entities on which the system depends. Let ${\displaystyle p(v)}$ be the probability that the system depends on ${\displaystyle v}$ external entities, ${\displaystyle p(v)=P(E=v)}$. Then, the system self-sustainability, ${\displaystyle S}$, is ${\displaystyle S=p(0)}$.
2. Let ${\displaystyle e_{t}}$ be the expected time during which the system is self-sustaining from time 0 up to time ${\displaystyle t}$. Then, the system self-sustainability is the steady state fraction of time in which it is self-sustaining, ${\displaystyle S=\lim _{t\rightarrow \infty }{e_{t}}/{t}}$

Maps Self-sustainability

Examples

Political states

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.

Labor

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.

Peer-to-peer swarming

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).

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Discussion

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.

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Notes and references

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See also

• Availability
• Homesteading
• Independence
• List of system quality attributes
• Self-sufficiency
• Survivalism

Source of the article : Wikipedia