White hat (computer security) certification covers orderly, ethical hacking techniques and team-management. Aggressor teams are called "red" teams. Defender teams are called "blue" teams. When the agency recruited at DEF CON in 2012, it promised applicants that "If you have a few, shall we say, "indiscretions" in your past, don't be alarmed. You shouldn't automatically assume you won't be hired". White hat (computer security) The term "white hat" in Internet slang refers to an ethical computer hacker, or a computer security expert, who specializes in penetration testing and in other testing methodologies that ensures the security of an organization's information systems. Ethical hacking is
Item-item collaborative filtering Earlier collaborative filtering systems based on rating similarity between users (known as user-user collaborative filtering) had several problems: Item-item models resolve these problems in systems that have more users than items. Item-item models use rating distributions "per item", not "per user". With more users than items, each item tends to have more ratings than each user, so an item's average rating usually doesn't change quickly. This leads to more stable rating distributions in the model, so the model doesn't have to be rebuilt as often. When users consume and then rate an item, that item's similar items are picked from