1. What data do Hare et al use?

The data format that Hare et al used was 3D topographical images, they also used 3 R packages which were randomForest, x3pr, and bulletr.

  1. In what ways do the methods used by Hare et al differ from the “traditional” methods of bullet matching?

Instead of using a comparison microscope they used algorithms to help measure striae and land impressions on the bullet. So rather than using the manpower on matching bullets they use more adavanced technology to help in their research.

  1. How do Hare et al use clustering to help perform bullet matching tasks?

In the video Hare et al did not specifically say the word cluster but we can see that they had seprated the known non-matching bullets, the known matching bulles, and the degraded bullets into cluster samples from using the R-code RandomForest.

  1. Identify one statistics and/or probability concept in the presentation that you have not heard of before. Do a little bit of research (Wikipedia is ok) and try to describe it to someone who doesn’t know about it. You don’t need to read it in its entirety, but you should also consult this paper to see if there is more detail on your chosen topic than is presented in the webinar.

In this presentation they talk about cross-correlation which is a measure of similarity of two series as a function of the displacement of one relative to the other. When it comes to statistics cross-correlation is used to refer the correlations of two random vectors such as X and Y. They use cross-correlation in order to search for matching striae and grooves on the bullets surafce.