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Most scheduling systems are "feedback systems." Such systems can become unstable under
certain conditions and produce erratic and unpredictable behaviors. Instability and fast
response are often opposed in such systems. This creates significant problems for the designers
and users.
Automatic Control and System Theory along with the new
branch of Physics known as Chaos
also contributes to our understanding. Chaos is quite common in scheduling and other business
systems.
While these pages are conceptual and theoretical, a basic understanding helps to understand
real scheduling systems and improve their performance.
Series Summary
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Scheduling systems are feedback systems, i.e., a controller
measures the current system state, compares it to a desired state and takes action to
eliminate the difference.
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Chaotic systems are similar to feedback systems in that the
future state depends on the current state plus some action. They are governed by precise
deterministic evolution equations, but have unpredictable and seemingly random behavior.
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Such systems are subject to instability and chaos.
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Ashby's Law implies that complex processes require complex
scheduling systems. When processes are simplified (as in Cellular Manufacturing) the
scheduling system can be simplified.
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Since complexity is a root cause of chaos and instability,
simple processes and simple control systems are highly beneficial.
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To Minimize
instability and chaos:
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Keep It Simple
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Implement Flow Lines & Cells
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Employ Kanban, Direct Link &
Broadcast
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Reduce All Time Delays
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Schedule Frequently
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Increase Linearity
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Minimize Unnecessary amplification
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