http://www.newgradiance.com

From Stanford University:
We have developed innovative technology, namely root questions, to get students to solve long-answer questions through the multiple-choice question format in a way that their evaluation can be easily automated. Unlike conventional homeworks, which are really little tests, Gradiance homeworks and labs are designed so the student is encouraged to learn from mistakes and, eventually, to get the assignment completely correct. Gradiance materials include explanations that help students whenever they miss a component of an assignment.

CSC 455 Students:
You will have unlimited attempts at each set of homework questions, but you must repeat every question in the set each time you retake it. Work the problem out on paper because when you retake it, you may have a different set of answers to select from. Note that the references to chapters or page numbers in the feedback do not apply to our book, so just disregard those. Gradiance uses an alternative style for E-R diagrams, so keep this reference handy as you work these problems.