In BAsCET, the activation value is propagated from a semantic node to another.

Let's start from the example shown in the link explanation.

/----------------\ /--------------\
| S: birthday | | S: cake |
+----------------+ +--------------+
| CI: 80 | /-----------------\ | CI: 70 |
| AV: 100 % +-----+ T: eat | W: 95% +-----+ AV: 0% |
| DR: 2 | \-----------------/ | DR: 5 |
| Ag: ComputeDay | | Ag: CookCake |
\----------------/ \--------------/

Propagating the activation value of `birthday` through the link `eat` to the node `cake` will give the following Concept Network:

/----------------\ /--------------\
| S: birthday | | S: cake |
+----------------+ +--------------+
| CI: 80 | /-----------------\ | CI: 70 |
| AV: 98 % +-----+ T: eat | W: 95% +-----+ AV: 86% |
| DR: 2 | \-----------------/ | DR: 5 |
| Ag: ComputeDay | | Ag: CookCake |
\----------------/ \--------------/

The activation value *AV*^{t+1}_{i} of a node *i* at the instant *t + 1*, after propagation, is expressed as the sum of its old activation value *AV*^{t}_{i} and the other nodes' influence *I*_{i}, minus a deactivation *D*_{i}, depending on its decay rate *DR*_{i}.

AV^{t+1}_{i} = AV^{t}_{i} + I_{i} - D_{i}

The influence of other nodes could be given by this classical formula:

I_{i} = (Σ_{j≠i} A_{j} x W_{ij}) / 100

but it lets an unbalanced influence between nodes with many neighbours (influencing them) and nodes with almost none.

That's the reason why BAsCET use a little more complicated influence, with a logarithmic behaviour.

As the `birthday` node has no incoming link, *I*_{birthday} is null.

D_{birthday} = 100 x 2 / 100 = 2

So, its new activation value *AV*^{1} = AV^{0} + I - D = 100 + 0 - 2 = 98.

As far as the `cake` node is concerned, it is different: its activation value is null, and so is its deactivation. However, it is influenced by `birthday`:

I_{cake} = (A^{0}_{birthday} x W_{birthday,cake}) / ( 100 x Div_{cake} ) = 100 x 95 / ( 100 x Div_{cake} ) = 95 / Div_{cake}

Div_{cake} = ln 4 / ln 3 ~ 1.0986, so I_{cake} ~ 86.

At last, A^{1}_{birthday} = 0 + 86 - 0 = 86

In this example, one could add a `candle` node, that would be associated to the `cake` and `birthday` symbols. One could add a link from `cake` to `candle` *labeled* by `birthday`; so, when `birthday` and `cake` are both activated, this link activate `candle`.