Searching for Similar Files

The content of files in the IS VŠEM data repository, for which a plain text version is available, is continuously machine-analyzed. Each document (final work, seminar work, essay, presentation, ...) that the user finds in the system can be compared and displayed with resources that have a similar text:

• click on the line with the file (right-click will bring up the details panel on the right, left-click will bring up the context menu),
• use the "Find similar documents" operation (two eggs icon),
• use the displayed similarities (or adjust the settings and have the similarities recalculated) to assess whether it may be plagiarism or not.

For similar documents found, IS VŠEM will list the degree of similarity in percent. There is also an overall calculated similarity of the document with others:

The similarity percentage is only an indication, the document or part of it may be plagiarism, even if the percentage is significantly low. Counting similar documents is fast, checking for similarities is possible immediately after creating a text version of the file.

People who have led or opposed the final work now or in the past are allowed to print the report in PDF format by expanding the "Modify search or select another document" menu, where they will find the "PDF output" option. Click this option and click the View button to open the log.

The system searches for similarities across the shared database of compared documents, which includes, in addition to the IS VŠEM document server, final theses of participating schools in the Theses.cz system, seminar and other theses in the Odevzdej.cz, system, scientific publications in the Repozitar.cz system and other documents in information systems operated by MU.

Because a significant amount of work and documents are not public, searching the common database is an effective tool for finding possible plagiarism. A student cannot just submit a seminar paper to a friend from another school, because there is a high probability that he is already in the system and there would be similarities. The assignment of seminar and final thesis topics is often repeated, and it is therefore likely that the system will already know about the source documents from which this topic is usually drawn.

The search for similarities also includes an algorithm that analyzes the document being compared and examines it from sources on the Internet. This procedure has various technical limitations and is computationally and time consuming. Therefore, it is preferably used for archives of final theses. Due to the speed of processing, seminar papers in submission offices and long answers in ROPOTs are primarily compared against a shared database of all source documents. This includes, among other things, resources from the Internet, which have been traced in the past for the purpose of checking some of the millions of final theses being compared.

However, there is a difference between finding similarities to seminar papers (for which the shared resource database is used) and final papers (for which the shared resource database is enriched with newly downloaded resources from the Internet). But there is no need to worry, the database is really large, so in most cases the system "knows" enough resources that students usually draw from, as well as enough resources that students usually describe.

The supervisor, who usually wants to check the quality of the work when writing the report, proceeds with the help of

and select "Find similar documents". They will see the total percentage of similarities and marked similarities, which they can use to scroll through the arrows and assess whether the sections are properly cited.

If you have a document in the form from which a text version can be created (it is not a picture, for example), insert it anywhere in the IS VŠEM (eg in the Provider, in the Study Materials of the subject or in My website) and IS VŠEM in the similarity search mechanism includes.

By default, documents from the same depositor are not compared. It is therefore necessary to click on the option "Modify search or select another document", select the option "include documents of the same uploader" and display:

This is a comparison of documents with each other:

• A text searchable version is generated for each document in the database. In this text version, the algorithm focuses on similar or paraphrased sections of text and evaluates the degree of agreement across the entire shared document database, including Internet resources.
• Texts in Czech, English and Slovak are compared, the condition is that they have at least a few sentences or paragraphs (in very small files there is not enough text for their analysis and finding similarities).
• Before the result is presented to the user, those documents that overlap only in passages that are the same as for previously found sources are omitted. Practically, for example, it is a citation of a certain law in another hundred final theses and documents on the Internet. If there are less than 10 similar sources, they will all be displayed without omission.
• The user is shown the most relevant documents that have a significant similarity to the document being searched, and the percentage of that similarity.

If students copy from each other, the system evaluates their answers as similar and displays the percentage of similarity. You can find more on this topic in the question How works compare similarities?

Authors can verify that their text has not been used in another author's work.

What the similarity search interface shows and how to use it:

Some similar documents do not provide information about the new match, only recurring similar passages of the displayed source documents. The system skips these documents. In practice, for example, these are more extensive citations of a certain law in another hundred final theses and documents on the Internet. Therefore, users will now not see all documents in which copyright law paragraphs are quoted, but will see only one of them. The one that has the most other similarities with the selected document.

First of all, you need to see if you just see another document that contains the similarity. For example, whether the system did not mark an equal collection of laws with the text of the law, and not a newspaper article commenting on the same article.

The system also checks longer texts entered as answers to ROPOTs. Answers to questions of the type "Enter text" (: a) are checked if more than 50 characters were entered. The system automatically inserts these answers into the Study Materials of the subject if the ROPOT is in the study materials. If the ROPOT is not in the study materials, then it is stored under the ROPOT description file. These files are not available to students by default.

The following can be used to check the answers in the ROPOTs:

The individual files, student names and similarity percentage are displayed. You can click on the similarities for each file (ie the individual long answers in the ROPOT) for a more detailed examination.

The similarity search tool can help prevent copying or resubmission of senior classmates' essays. If students copy from each other, the system evaluates their answers as similar and displays the percentage of similarity. To check the work in the delivery room, use:

The individual files, student names and similarity percentage are displayed.

Plagiarism (copying, imitations) is an unethical activity and fraud that has no place in college. Acceptance of the text of another author without a visible indication of the copied text with the exact citation of the source constitutes an unauthorized infringement of copyright in violation of copyright law. There is a risk of sanctions for the offense, even after graduation.