In the figure above, which number refers to the current reference point?

How can a website distinguish between lack of capacity and a denial-of-service attack? For example, websites often experience a tremendous increase in volume of traffic right after an advertisement with the site's URL is shown on television during the broadcast of a popular sporting event. That spike in usage is the result of normal access that happens to occur at the same time. How can a site

determine that high traffic is reasonable? What will be an ideal response?

For binary data, the L1 distance corresponds to the Hamming distance; that is, the number of bits that are different between two binary vec- tors. The Jaccard similarity is a measure of the similarity between two binary vectors. Compute the Hamming distance and the Jaccard simi- larity between the following two binary vectors.

This exercise compares and contrasts some similarity and distance measures.