The senior class of 2010 graduated from South Philadelphia High today, ending a tumultuous year defined by the violence of Dec. 3, when 30 Asian students were attacked by mostly African American classmates.

Philadelphia Schools Superintendent Arlene Ackerman, who normally does not attend graduations, made a special trip to speak at the ceremony, saying it had been "an unusually difficult year for the students at Southern."

Like other speakers, she did not directly acknowledge the violence that sent seven students to hospitals and spurred three separate investigations.

She asked graduating members of the Student Ambassadors and the 50-50 Club, designed to promote understanding at the school, to stand and be acknowledged. They "help bring different cultures together in a positive and productive way." Ackerman said.

Since Dec. 3, the district has installed 126 additional security cameras, which students say has decreased commotion in the schools.

Top Philadelphia school officials also say that students at Southern, as the school is known, have responded to new programs aimed at building bridges. However, Asian students and advocates say that serious, systemic bias issues persist - and that district officials refuse to address them.

Senior Wei Chen, who helped lead a weeklong 50-student boycott of classes after Dec. 3 stood dressed in a black graduation gown, pants, and cap, awaiting his diploma.

"I'm happy I'm graduating. I'm so glad. I've done my job - almost done," Chen said.

Otis D. Hackney III, the principal of Springfield High School in Montgomery County, will become the permanent principal for next school year. He takes over a school that has long failed to meet state performance standards and been labeled "persistently dangerous" under federal law.