FAQ - CMUCTAT/CTAT GitHub Wiki

Q: What is the goal of CTAT?
A: To significantly reduce the amount of time needed to create a tutor, and to lower the amount of artificial intelligence programming expertise needed.

Q: Who is using CTAT?
A: Learning science researchers, online course developers, teachers, and students of cognitive science.

Q: What software do I need to develop tutors with CTAT?
A: Besides CTAT, you will need either Firefox or Chrome and the Google Drive app or the Dropbox app. If you're interested in authoring production rules, you will need an editor such as Eclipse. All of the software is free.

Q: What skills do I need to build tutors with CTAT?
A: You don't need any programming experience to create Example-tracing tutors; creating Cognitive tutors, however, requires familiarity with the Jess production rule language.

Q: I've modified my HTML interface after creating a behavior graph, but when I open the interface, the changes I've made to the HTML interface are not displayed.
A: When you create the start state for a behavior graph, values from the interface are stored in the graph (prior to CTAT 4.2). If you change the HTML interface, you need to update these values in the graph. To update the graph:
1. Open the graph.
2. Open the modified HTML interface.
3. Select Graph > Revise Start State with UI from the menu.
4. Reload the HTML interface, verify that the interface now displays the changes as defined in the modified interface, and save the graph.

Q: I've downloaded an HTML example interface, and when I try to launch it from the authoring tools, the tutor isn't connecting to the Behavior Recorder.
A: In the .html file, change the reference to JQuery to point to the version on the CTAT CDN:
<script src="https://cdn.ctat.cs.cmu.edu/releases/latest/jquery.min.js"></script>

Q: Can a tutor-performed action (TPA) execute a JavaScript function I've defined in the user interface?
A: Yes. In a TPA, if the Selection is "root" (entered in the Edit Student Input Matching dialogue), then the Action will be interpreted as a function name on the JavaScript global object (the window object), and the entire Input will be a single string argument passed to the function. For example, a TPA with Selection-Action-Input (root, alert, Hello there) will call the alert() function to pop up a dialogue showing "Hello there" on the student interface.

Q: When I use the HTML5 Project Wizard to create my tutor, should I elect to include local JavaScript and CSS files?
A: In most cases, no. By default, your tutor will include references to the JavaScript and CSS files hosted on the web (e.g., http://cdn.ctat.cs.cmu.edu/releases/latest/). The advantage of using the files hosted on the web is that your tutors will always have access to the latest version.

If you choose to use local files, however, those files are downloaded from the internet and saved in your project, and the generated .html file will include references to these files. Your tutor will always use the version of the files saved in your package, so when you deploy your tutor, you will also need to deploy these files.

Q: I've got Flash installed with the components but the resulting tutor I create isn't connecting to the Behavior Recorder.
A: Please try the following. From the File menu select Publish Settings. You should see a setting on the lower right called: Local playback security. Please make sure that "Access network only" is selected. Click OK and try running the tutor again.

Q: Why doesn't CTAT evaluate actions when I work with the Flash tutor?
A: A number of things could prevent CTAT from evaluating user actions. Here are some things to check:
- Author Mode not set to Test Tutor. Make sure "Author Mode" is set to "Test Tutor" in CTAT. Not using "CTAT for Flash". Perhaps you mistakenly launched "CTAT for Java"? Components don't each have a unique instance name. Check this by selecting each component and examing the instance name in the Properties panel. Alternatively, you can select Window > Movie Explorer and scan the list of component instance names (the text inside the brackets).
- Behavior Recorder Mode is set incorrectly. If you're working from the Flash IDE, check the Behavior Recorder Mode parameter of the CommShell component. If you're viewing the tutor from a web page, check the BehaviorRecorderMode parameter of flashvars. If you're connecting to the Behavior Recorder, it should be set to "AuthorTime".Using "screens" in Flash. CTAT currently does not support Flash interfaces that contain screens. Made changes to the Flash interface—renamed components, for example—after building a behavior graph. Either recreate the graph, or change the instance names in the interface back to the way they were when the graph was created.

Q: Start State doesn't load.
A: The two relatively common causes for this:
- The Flash Player's security settings are restricting it from sending data to CTAT (this may be the case when using the Tutoring Service). See Flash Player security for information on allowing the Flash movie (SWF) to communicate with CTAT.
- The behavior graph is not loaded, either because the path to the graph (specified in the flashvar "question_file") is incorrect, or the file doesn't exist. If using Flash's "Runtime" mode, the path should be relative to the HTML document; if using "AuthorTimeTutoring" mode (Tutoring Service), the path is relative to the CTAT executable (ie, the Tutoring Service).

Q: When I try to build a tutor in CTAT, Eclipse won't run my code and gives me an error in the console that certain classes aren't found.
A: On the Libraries tab, select all entries beginning with CTAT/deploy and click Remove. Note: Failure to do this step will result in an error when you try to run your tutor: "(java.lang.SecurityException: class someClassName's signer information does not match signer information of other classes in the same package". For more informatin please visit the CTAT Java Configuration Help Page.