CSEE : Communication System for Electronic Education

last update: 01 May 2007

source code:  CSEE-source.zip
executable:  CSEE.zip

Requirement for Compilation

1. Overview of CSEE

 We developed a multi-directional on-line lecturing system that shares 2D/3D geometric figures among multi-users over the network.  Instructor can share the display of PPT/PDF/image files with students at distant locations using the Internet communication.  The display is controlled in the same as the instructor and the students would control the same computer.  They can draw underlines and scribble notes and marks on the slides.  The result is shared among all users participating in the lecture.

 The system also supports a simple 2D/3D geometric modeler for drawing conic curves, function graphs up to quadric functions, and 3D figures such as spheres, cubes, cylinders, cones, and extruded polyhedra.  Lectures can easily be saved with voice, display control, handwriting, all recorded as an animation. The developed system has been successfully used in distance lecturing between Seoul and Busan, which are two cities located more than 400 km away.

2. Slideshow View

In Slideshow view, you can load PPT/PDF or image files into CSEE, and start a lecture.


Figure 1: CSEE

Click File-Open... to load a file, there will be a progress dialog popping up. (Figure 2)


Figure 2: File is being read

Once the file has been loaded, the lecture file will appear on the screen. Now we can draw on the slides using Tablet pen or move to other pages.


Figure 3: Lecture slide


Figure 4: Drawing on the slide

To start distance lecture between an instructor and students, select Network-Connect..., and a connect dialog will show up. The instructor sets his/her computer as a server, and students connect to the instructor’s computer to participate in the lecture. In the current implementation, the instructor needs an IP address. The system automatically sets an IP address from network configuration. The instructor needs to set a port number and press Create button. The students need to type in the instructor’s IP address and press Connect button to participate in the lecture. Once the connection between the instructor and students is established, their activities are synchronized.


Figure 5: Instructor’s computer


Figure 6: Instructor’s computer


Figure 7: Student’s computer

3. Lecture recording

You can record your own lecture using CSEE.


Figure 8: Start lecture recording

Lecture recording toolbar is similar to those of a cassette player. You can start recording by pressing a button with small red circle. Voice, scribbles, transitions between views on CSEE will be recorded during the lecture recording.


Figure 9: Recording tool bar

When you select View-Recording Window, you can edit a recorded file.


Figure 10: Edit recorded file

4. 2D Board

1.      2D Drawing Features Supported by CSEE.
(1) Conic section drawing by free-hand sketch and interactive editing.
      - Parabola, Ellipse, Hyperbola
(2) Conic section drawing by entering coefficients.
(3) Fitting free-hand sketch to a conic section by the SVD method.
(4) Polynomial function drawing (up to quartic).


2.      Conic section drawing by free-hand sketch and interactive editing.


(1) Conic primitive drawing and editing.
      Step 1. Select    (parabola drawing tool) on the toolbar.
      Step 2. Sketch a parabola in one stroke as follows.

      Step 3. CSEE will automatically change the above sketch to a fitted parabola.
                    You can also see the equation of this curve on the right tab view.


      Step 4. Drawing an ellipse.
                    Select ellipse tool  on the toolbar.
                    Sketch an ellipse within one stroke.


                    A fitted ellipse of the above sketch will show up as follows.


      Step 5. Drawing a hyperbola.
                    Select the hyperbola tool .      
                    First, click the center position of the hyperbola.
                    Then sketch a half of the hyperbola (right, left, upper or lower half).


                    A fitted hyperbola will show up as follows.


      Step 6. How to edit…


                     First, select the object you want to edit.
               Find the equation of the object on the right side and select it, then the selected object can be edited.
                In the editing mode, the object will change its color and its control points will show up.
                If you want to drag one of the control points,
                you have to select “Operation > drag to modify (discrete)” on menu and drag a central point.
                Changes in control points produce different effects according to the object type and the role of each control point of that type.

      - Parabola -
      1, 5, 2, 4 : Control the width of parabola.
                  3 : Control the position of parabola (center position)
      - Ellipse -
      1, 3 : Control the height of ellipse.
      2, 4 : Control the width of ellipse.
          5 : Control the height and width of ellipse simultaneously.
          6 : Control the center point of ellipse.

      - Hyperbola -
      1, 3, 4, 6 : Control asymptotic curves of hyperbola.
              2, 5 : Control focus distance of hyperbola.
                  7 : Control center position of hyperbola.

3.      Conic section drawing by entering coefficients.
You can draw a general conic section by entering coefficients of each term in a dialog box.
First select “Operation > Conic Drawing” on menu.
Then enter coefficients into edit boxes of each term, and set a bounding box in which the conic section will be drawn.
You can select the number of samples of the “Marching Cube” algorithm.
Then push the (re)Draw button to draw it on the canvas.


This figure shows 2x^2 + xy + 2y^2 + 4x + 6y – 9 = 0.

4.      Fitting free-hand sketch to a conic section by the SVD method.
Your freehand sketch can be fitted into a general conic section by CSEE.
Select “Operation > Semi-Automatic Conic Fitting” on menu.
Sketch any shape you want, then a conic equation (fitted by the minimum square solution of the SVD method) will show up.


This figure shows a freehand sketch (red curve) and a fitted conic section (black ellipse) and its equation on the right dialog.

5.      Polynomial function drawing. (up to quartic)
You can draw a graph of polynomial functions up to quartic polynomial.
Select “Operation > f(x) Function Drawing”.
Enter coefficients and domain range and line segment sampling intervals, then push the draw button.


Example screen of f(x) Function Drawing operation.

5. 3D Board

You can create 3D objects using toolbar. For a free drawing, the default drawing plane is the XZ plane. You can draw a point and extrude it to a line, extrude a line to a plane, and extrude a plane to an object. There are also predefined primitives.


Figure 11: 3D Board tool bar


Figure 12: Free drawing


Figure 13: Extruding from polygon

You can select an object by clicking. Every time you click on the window, CSEE decides which one to select. If there are more than one object, you can select one by clicking twice or more on the same point. You can also put auxiliary information.


Figure 14: Show auxiliary information


Figure 15: Show auxiliary information

Objects created in 3D Board can be imported into Slideview.


Figure 16: Import from 3D Board