Abstract
Plagiarism is a common problem in education, and detecting it is a very difficult task if a marker is
responsible for marking only some of the scripts. The situation becomes worse for distance learning
as some students are allowed to submit assignments after the due dates and markers may have to
mark assignments over quite a long period of time. They might forget ësimilarí scripts that they
marked some time before. This chapter introduces an integrated online assessment system for
markers to detect plagiarism of program codes in a more structured, less computational and more
flexible way. We propose a new algorithm using parse tree for detecting plagiarism of programming
codes. The use of parse tree introduces a structured and systematic way for detecting similarities
among computer programs. The assessment system provides multiple features to aid in the effective
marking of assignments, such as plagiarism detection, automatic program testing and students
performance statistics. The aim of these features is to relieve the burden of teaching staff and
provide an alternative way to paper-based marking.