LTSN-ICS Plagiarism Workshop 2002 Prevention better than cure? The case for Plagiarism Detection...

LTSN-ICS Plagiarism Workshop 2002

Prevention better than cure? The case for Plagiarism

Detection

H.C. Davis

IAM: Learning Technologies

Electronics and Computer Science

University of Southampton


Structure of this Talk

(Largely concerned with Source Code Plagiarism)

• What is plagiarism?

• The causes of plagiarism?

• Approaches to preventing plagiarism

• Detecting Source Code Plagiarism

• Case Study using JPlag


What is Plagiarism

Obviously direct wholesale copying of source…but– How much source should be the same in

well written solutions to a small problem?– What about buddying and team working?– How are we going to catch sub-contractors?


Some Thoughts

• It is very difficult to prove copying

• It is even more difficult to prove sub-contracting

• This talk assumes that our intention is to prevent plagiarism rather than to get involved in post-hoc legislatation


The causes of plagiarism?

• Over assessment

• Unrealistic expectations

• Strategic/cynical time management

• Cultural expectation

• Team working

• Fear of failure

• Laziness


Approaches to preventing plagiarism (1)

• Clear university/departmental policyNeeds to define– What is plagiarism?– What will be done?– The borderline between acceptable collaboration

and unacceptable plagiarism



• Signed statements from students

Give them the opportunity to admit to what they needed to borrow in order to complete the assignment



• Logbooks

and

• Time-stamped code development

It is hard to reverse engineer this stuff (especially without learning!)



• Reduce assessment load

• Diversify type of assessments– (peer marking and review, multiple choice

questions, self assessed team assignments)

• Establishing a culture of learning (rather than mark grubbing)



• Detection

• Naming and shaming


Detecting Source Code Plagiarism

• Must have all code on-line (floppies or hard copy not helpful)

• Simple searching for suspicious strings

• Scripts as above

• Simple byte code comparisons

• Specialised tools (JPLAG, MOSS, Coursemaster)


Case Study Using JPLAG

Getting Started

• First get yourself registered with JPlag at http://www.jplag.de/

• (email [email protected])

• Download the JPlag applet


2. Collect Student Assignments

• JPLAG expects one directory per student. That coursework can have subdirectories and JPLAG doesn’t care what the files are called.

• At Soton we have a handin machine which supplies a ZIP file of exactly such a directory file with the student’s username as the directory name, so all you have to do is unpack it where you want it.


Run the Applet>c:\jdk1.3\bin\java –jar C:\jdk1.3\jplagapplet.jar

After a few minutes you will be able to see the results

LTSN-ICS Plagiarism Workshop 2002 Prevention better than cure? The case for Plagiarism Detection...

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