Scenario Control Units
.
To sustain life, a living system's governance mechanism must continually take corrective actions to maintain its internal conditions within prescribed limits. These corrective actions are accomplished through scenarios, which consist of sequences of action steps to restore the required homeostatic balance.


Scenarios for Life's Actions
.
To sustain its life, a living system must maintain homeostasis, where all of its internal conditions are balanced and kept within prescribed limits. There must be a constant supply of nutrients being transformed into energy and needed materials. Temperature must be kept within certain bounds, and metabolic processes must be sustained while the external environment constantly changes.
.
Scenarios are the internal model's way of defining the action sequences that carry out the living system's life functions. The process of living can be thought of as a myriad of scenarios being acted out in concert. Each individual scenario represents an effort to help satisfy some real or perceived need of the living system.
.
Hierarchical Structures
.
Scenarios are usually grouped into hierarchical structures, that reflect abstractions of the higher- and lower-level actions to be taken. For example "dining" would be a high-level sequence of actions, from sitting down at table to loading food on plate, eating food, etc. Lower-level actions might include picking up fork, spearing morsel of food, and lifting fork to mouth. Further scenario details might include operating muscles in arm to move hand toward fork, closing fingers around fork, etc.
.
Because a living system is continuously impacted by ongoing interactions with its environment, higher-level scenarios are seldom carried to completion without some corrective intervention. Suppose the morsel is stuck to the dish? The resulting situation will require some kind of change in the scenarios. The higher-level scenario of "eating" may continue as planned, but at a lower level a new scenario must be introduced to compensate for the disturbance.
.
Scenario Structure
.
Unless interrupted, a scenario proceeds as an orderly sequence of steps, that can be viewed as a process:
.
action
step
check
result
action
step
check
result

However, a scenario does not exist in isolation. Within the governance mechanism, each scenario is linked to other scenarios and sensed patterns, forming a complex network of relationships that facilitate their identification and retrieval for a particular situation or condition. When a scenario is activated, its sequential process is incorporated in a control unit that monitors each action step to see if the process is on track.
.
As each action step is taken, the expected resulting sensory pattern is checked against the actual pattern coming in from the senses. If they match, the scenario continues to the next action step. If they do not match (exceed some threshold of difference), corrective action is taken by substituting a different scenario.
.
When such a discrepancy occurs, a more appropriate scenario can usually be found within the internal model's memory, which stores the entire repertoire of existing scenarios and indicates which ones may be related to the current situation. An appropriate matching scenario is then activated to replace the original one. If no such substitute can be found, a higher level reasoning capability is invoked to develop a new, more suitable scenario to deal with the new situation or condition.

Scenario Control Unit




In this diagram, the Director determines how to respond to a new situation or condition. The Administrator presides over the repertoire of existing scenarios in memory, activates the one that is needed, and constantly tests its progress against actual sensory input. As the Administrator initiates each action step, the Implementor orchestrates relevant organization units to carry out the action in a coordinated manner.
.
This control unit structure is invoked for each active scenario, whether conscious or autonomic. When a hierarchy of scenarios is required, they are activated and controlled within a hierarchy of scenario control units.



Who is in Control examines the underlying nature of control and who applies it.


©1995-2012 Ackley Associates   Last revised: 7/19/11
.