Who were the students who failed the course "Applied Deep Learning"? Give the full name.
If grade is null or empty, it means that this student fails to pass the course in which grade = NULL;
SELECT T1.f_name, T1.l_name FROM student AS T1 INNER JOIN registration AS T2 ON T1.student_id = T2.student_id INNER JOIN course AS T3 ON T2.course_id = T3.course_id WHERE T3.name = 'Applied Deep Learning ' AND T2.grade IS NULL