More than 350 teens are expected to attend the eighth annual Somerville Youth Peace Conference on Saturday . The conference will feature performances by Somerville teens and is being presented by the Center for Teen Empowerment, a Boston-based nonprofit organization, along with city agencies and the school district, with Mayor Joseph Curtatone expected to attend. The conference, which will be held from 5 to 8:30 p.m. at the East Somerville Community School at 50 Cross St. , will examine teen violence, substance abuse, immigration, bullying, and other issues. Teens will also be able to share their experiences in an open-microphone session. Tickets to the conference will be $3 at the door.