Sketchmate: A Computer-Aided Sketching and Simulation Tool for Teaching Graph Algorithms Dissertation Proposal Kristy VanHornweder April 11, 2011

Disadvantages of Traditional Teaching Methods Transitions between steps not clear Hand drawn diagrams are time consuming and prone to errors Difficult to revert to previous steps Erasing/redrawing diagram loses history of algorithm’s progression Recopying data structure is inefficient

Advantages of Computerized Simulations Transitions between steps more clear No need to erase or recopy diagrams Can contain domain-specific knowledge Can provide immediate feedback on solution Can easily revert to previous steps Could function as enhanced whiteboard

Sketchmate for Graphs Will build on Mike Orsega’s Sketchmate for splay trees Will demonstrate shortest path and network flow algorithms Two versions –Instructor tool: For teaching graph algorithms during lecture –Student tool: For students practicing homework exercises and obtaining a grade and feedback Fundamental difference: Will involve simulations manually executed by human users, in addition to automated slide shows

General Outline Related Work Research Goals Sketchmate Environment Walk-through example Experiments Conclusion Timeline

Related Work Outline Effectiveness of AV Tools AV Tools for Computer Science General Presentation and Annotation Tools AV Tools for Graphs Sketchmate for Splay Trees

Effectiveness of AV Tools More effective if students actively engaged Text & images together more effective than text & images separate Must carefully choose text accompanying an image Detailed feedback more effective than no feedback, but verbose feedback less effective

AV Tools for Computer Science Playback –e.g., PowerPoint, Flash Programmatic –e.g., BALSA, XTANGO Tutorial –e.g., Problets

General Presentation and Annotation Tools Annotating slides with notes –e.g., ScreenCrayons Connect to shared whiteboard –e.g., PDAs, handheld devices

AV Tools for Graphs: Features of Interest Continuous display of steps Discrete step-by-step display with pauses Stepping back to previous steps History list of operations for reversion Animations of objects (moving, flashing)

AV Tools for Graphs: Features of Interest, con’t. Allows creation of custom graph Textual description of each step Allows manual practicing of problems Grading user’s solution Providing detailed feedback of solution

AV Tools for Graphs: Taxonomy Tree

Sketchmate for Splay Trees Similarities –Both instructor and student tools –Create custom graph, simulate, revert –Practice problems, grade, feedback –Experiments with usability and learning rate Differences –Graphs instead of splay trees –Instructor manually simulate algorithm –Manually simulate arbitrary graph algorithm –Notepad feature –Student can practice with any input graph

Research Goals: Instructor Tool Additional Features Manual simulation mode Can manually simulate arbitrary graph algorithm Revert pane for viewing any previous step Display both previous and current steps Notepad feature for explanations Checking manual solution with automatic solution Easy, fast, convenient, efficient, low learning curve Mixed modes of delivery: visual and audio

Research Goals: Student Tool Additional Features Display both previous and current steps Easy, fast, convenient to use Can practice on any custom-made graph Increase student learning rate

Sketchmate Environment Create Pane Simulate Pane Revert Pane Student Simulate Pane

Sketchmate Create Pane

Sketchmate Simulate Pane

Sketchmate Revert Pane

Sketchmate Student Simulate Pane

Walk-through: Initial State

Walk-through: After Visiting s

Walk-through: While Visiting x and Updating y

Walk-through: While Visiting x and Updating u

Walk-through: While Visiting x and Updating v

Walk-through: After Visiting y

Walk-through: After Visiting u

Walk-through: After Visiting v

Experiments: Instructor Tool Group of CS graduate students Half will present lecture with Sketchmate, other half will present with whiteboard on same graph problem Will use Create, Simulate, Revert Measures –Likert scale for usefulness and appeal –Time to prepare lecture –Time to present lecture –Accuracy of lecture

Experiments: Student Tool Group of CS undergraduates Half will use Sketchmate to do HW problem, half will use paper & pencil Two problems: Dijkstra’s shortest path and network flow Each student use both methods: one method for one problem, other method for other problem Each student: pre-test and post-test Measures –Likert scale: which technique preferred –Learning outcome –Learning rate

Conclusions Want to create an interactive, dynamic classroom environment –Goal: Easier, faster, more efficient preparation and presentation of lectures Students can practice exercises and obtain detailed immediate feedback –Goal: Improve learning rate and reduce amount of time to complete homework

Timeline