We are introducing an online tool for solving signal flow graphs (http://en.wikipedia.org/wiki/Signal-flow_graph
We are targeting the "Educational App" category for Google Developers challenge by providing a new interactive tool for drawing and solving signal flow graphs. The app also can be used for demonstrating the concept of loops and cycle finding involved in the process of solving signal flow graphs.
Thanks for Google APIs, we were able to enhance the app and provide additional features including the interactive and cooperative environment that allows several Google+ hangouts participants to build and solve the signal flow graphs simultaneously and face-to-face.
We have also used the Google Drive API to provide features like saving and loading of graphs to the users' Google drive accounts.
Once the user loads the app main page, the user can start adding nodes directly to the sketching canvas. The user can also connect the nodes with Line or Arc Edges. By Clicking on an Edge the user can adjust its curvature or label (gain). Also Movement of nodes or edges is possible. The User can also change the numeric value of any symbol from the symbol table that appears beside the sketching canvas.
Once the user finishes building the Signal flow graph, the user can click on the solve button to get the Symbolic as well as the numeric transfer functions.
At any time the user can save the graph to his Google Drive account by clicking the save button. (providing that he has already authorized the application with his account from the button on the top right corner of the app).
To use the hangout feature, the user can click on the hangout button on the top right corner of the app page.The user can invite several participants from his Google+ Circles. Updates to the graph is synced automatically to all participants.