The Similarity measure between object X and

the center of cluster Z is written as follows, okay.

This is the similarity, we can see distance measured,

distance function, okay.

For the jth field of object x, that means x sub j, and

look at the jth field of the cluster center z, what's a distance?

It essentially is if this object is not equal to the center on the same attribute,

essentially say they are different, then we just say the distance

is one because it's very dissimilar, or the distance is largest.

However, when this value is equal

to this attribute center here then we use this formula.

This formula actually means if there are many many objects occur

the same in this cluster, okay.

Then, this value actual be very small.

For example if the attribute cluster, there's only one value.

But if very frequent, then this guy have to equal to this value.

Then, this division where it lead to one, and the distance is smallest.

In most cases, the more frequent for this j value,