Network/Interactive Activation


Interactive activation network boxes contain nodes with associated activation values. Nodes within an interactive activation network may be created or deleted and excited (or inhibited). Their activation values may also be queried.

The initial contents of an interactive activation network are the set of (names of) nodes initially contained in that network. Initial activation values are set with reference to the box's properties.

Nodes may be added to an interactive activation network at any stage in processing through the use of add actions:

Nodes may be deleted from an interactive activation network at any stage in processing through the use of clear actions, delete actions, and delete all actions:

The first of these removes all nodes from a network. The second deletes one node (whose name unifies with NodeName). The third deletes all nodes whoses name unify with NodeName.

Interactive activation networks will normally co-exist with a process which sends appropriate excite messages to control the node activations.

On each processing cycle, the total excitation to each node within the network is summed. This net excitation is then used, along with the current activation and network activation properties to determine the new activation of each node.

In addition to external input, node activations may be subject to internal competition, using Lateral Inhibition and Self Activation. Each of these can be configured by additional properties, allowing them to be enabled separately, scaled appropriately, and to use alternative baselines. Lateral Inhibition can be configured to use any of several different functions, and it can be calculated over the whole network or within subnets, which partition the set of nodes in the box into several effectively separate networks.

If Subnet competition is selected, NodeName must be specified as a binary structure using the slash operator ("/"), in which the first argument is the name of the node, and the second is the name of the subnet, e.g. mynode/mysubnet. Then this node will only compete with others belonging to the mysubnet subnet.

The last operation available on networks is matching. The activation value of a node may be queried by matching against the node's name:

The above code segment may occur in the conditions of any rule or condition definition that can read Network. Normally Activation will be an uninstantiated variable, and execution of the conditon will bind that variable to the activation of the node whose name is bound to Name. As with buffers, the match operation will attempt to resatisfy if any part of the node definition is uninstantiated.


Interactive activation networks are highly configurable. A total of sixteen properties govern their behaviour: