OJS Plugin: Recommender System

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Posts: 6
Joined: Fri Oct 28, 2011 2:07 am

OJS Plugin: Recommender System

Postby junsky » Fri Oct 28, 2011 2:55 am

--Edit 25.09.2012 --
The current plugin has been attached in a post below.

Hello everybody

I'm developping a Plugin for OJS (2.3.6) for my Master Thesis (TU Graz - Austria). It is a recommender system, one part of the recommendations is content based by computing the cosinus-distances between the abstract texts, the second part is done by tracing the user paths.

I used a Generic Plugin and started to build my plugin like the existing plugins in the generic folder.
Everything works fine on my tesing system (xampp, OJS (2.3.6) on windows) but on the live systems ( OJS (2.3.6), linux) there is some sort of strange behaviour.

If I activate my plugin, the download of pdf files is broken - the browser renders the content of the pdf-file directy instead of downloading it.
(The last line of the output displays an error:
Call to a member function getRouter() on a non-object in /home/zfhe/public_html/ojs-2.3.6/lib/pkp/classes/template/PKPTemplateManager.inc.php)
This happens even if I dont use any Hook.

The rest of the plugin works - the recommendations are displayed correctly under the article abstract, the hooks for downloading and viewing a file are called too (the user paths are written into the databse) only the download of a pdf file itself does not work anymore. (the viewing of a pdf file works)

I attached the plugin if someone wants to try it out (If the plugin is enabled the first time it fills its content-based database tables - depending on the amout of published articles this can take some time - 80 articles around 1min - 300articles ~8min)

I would be glad if you could take some time to try it out and see if the error occurs too in an other test system, or if someone has an idea where I made the mistake.

thank you

buggy plugin removed.
Last edited by junsky on Tue Sep 25, 2012 5:23 am, edited 4 times in total.

Posts: 6
Joined: Fri Oct 28, 2011 2:07 am

Re: Plugin development - download PDF does not work anymore

Postby junsky » Sat Oct 29, 2011 3:49 am


sorry for bugging you, but i found the error. I had an additonal newline in one of my plugin-files. So it broke the html-header and the pdf was not recognized as downloadable file.

I attached the final plugin version - It is running on three journal installations to see if the algorithms produce some useful results. Feel free to test it yourself.
Localization is english and german.

Thank you.

edit: Plugin removed - current version added in last post
Last edited by junsky on Fri Nov 25, 2011 4:16 am, edited 1 time in total.

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Joined: Tue Feb 14, 2006 10:50 am

OJS Plugin: Recommender System

Postby jmacgreg » Thu Nov 03, 2011 5:13 pm

Hi Martin,

Thanks for letting us know what you are up to, and providing the plugin as well! I've moved this thread to the Plugin Galley forum, where we typically store and track user-supported plugins. Do you have any research documentation, etc. online related to this project? We'd love to hear how you came about doing this for a Master's Thesis.


Posts: 6
Joined: Fri Oct 28, 2011 2:07 am

Re: OJS Plugin: Recommender System

Postby junsky » Fri Nov 11, 2011 12:38 am

Hello James,

i'm working on the plugin to improve the results. Some minor bugs will be removed with next version.

Unfortunately I'm writing my Thesis in German and the Plugin is built for German language analysis (the content-based-filtering approach)
For dealing with english language, you have to add a stopword-list for english words and to implement the stemming algorithm for english.
This classes can be found in the /utils/lib Folder of the Plugin.
Or just remove the PorterStemFilter from filtering pipeline (in Class RSTextAnalyzer -> /utils).

I'll post the next version if its ready to use.


Posts: 6
Joined: Fri Oct 28, 2011 2:07 am

OJS Plugin: Recommender System: Current Version

Postby junsky » Fri Nov 25, 2011 4:15 am


here is the next version. Some bugs with the collaborative filtering part are fixed and the algrithm is extended. For best performance, a clean re-install of the plugin is recommended. (Remove the plugin and delete the rs_* tables in the database.)

greetings martin

edit 25.09.2012
some warnings created by the plugin have been reported and are removed now in the current version.
current version
(34.61 KiB) Downloaded 221 times
Last edited by junsky on Tue Sep 25, 2012 5:35 am, edited 2 times in total.

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Location: delhi

Re: OJS Plugin: Recommender System

Postby ushasharma84 » Wed Jan 04, 2012 4:42 am

Hi all
can this recommender system plugin be used with ojs-2.3.4. when i am trying to install it I am getting errorInstallation failed DB: ##installer.installParseEmailTemplatesFileError##. waiting for a reply.

Thanks in advance

Posts: 6
Joined: Fri Oct 28, 2011 2:07 am

Re: OJS Plugin: Recommender System

Postby junsky » Mon Jan 09, 2012 7:37 am

Hi ushasharma84,

this plugin is only available for OJS 2.3.6. There are no plans to develop a OJS 2.3.4-Version.

greetings martin

Posts: 6
Joined: Fri Oct 28, 2011 2:07 am

Update v 1.6.105

Postby junsky » Tue Sep 25, 2012 5:37 am


a new version has been added. See post above

greetings martin

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