Given who-watched-which TV transaction data, how can we recommend relevant TV programs for a given user? Given a frienship social network, how can we recommend friends that are likely to make connections to a given user? Recommendation is an important application of data mining, and is widely used in movie recommendation, restaurant recommendation, job recommenation, article recommendation, and friend recommendation. In this project, we work on designing and developing models, algorithms, and systems for recommendation. We focus on the following two types of data.