url - Universität zu Lübeck
url - Universität zu Lübeck
url - Universität zu Lübeck
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154 CHAPTER 8. KEYX IMPLEMENTATION DETAILS<br />
Figure 8.9: Managing lectures with XDLT<br />
The teacher groups exercises to courses and assigns them to students. The learning<br />
progress can be monitored because exercises passed by an individual student<br />
are tracked and stored on the web server. An exercise based on XPath is shown in<br />
figure 8.10. This exercise has a task description that is not part of the figure. The<br />
selected nodes are highlighted and compared with a predefined correct solution.<br />
A context-sensitive assistance is offered by the system if the students proposed<br />
answer is not fully correct. For further details on this educational system we refer<br />
to [48].<br />
Figure 8.10: The XDLT query interface<br />
The XPath interface of KeyX and its established indexes are accessed by a servlet<br />
that generates HTML pages to create new indexes and to use them in order to<br />
execute ad-hoc queries. The queries can be performed with and without a suitable<br />
index in order to see the difference in execution time. Additionally, XDLT<br />
measures the time needed for the query execution. Therefore, XDLT can be seen
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