Notes From Class
Notes From Class
Week 1: August 30. September 1 and 3, 2004
Week 2: September 8 and 10, 2004
Week 3: September 13, 15 and 17, 2004
Site IP addresses
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wam.umd.edu 128.8.10.141
128.8.10.142
128.8.10.143
glue.umd.edu 128.8.10.68
128.8.10.71
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Week 4: September 20, 22 and 24, 2004
Week 5: September 27 and 29, and October 1, 2004
You are all invited to attend the CS Department's first Colloquium of this academic year which will be held in the CSIC Lecture Hall, room 1115 on Thursday, September 30 beginning at 3pm. Dr. Michael Kass from Pixar Animation Studios will speak about the fascinating work being done by Pixar animators. He, along with David Baraff and Andrew Witkin, developed physically-based clothing and hair animation software that was used in "Monsters Inc." and a forthcoming film The Incredibles.
Week 6: October 4, 6 and 8, 2004
Week 7: October 11, 13 and 15, 2004
Week 8: October 18, 20 and 22, 2004
Week 10: November 1, 3 and 5, 2004
For each problem, hand in a copy of your program source code and a script file showing the I/O of typical program runs.
Due date: November 10, 9am.
Week 11: November 8, 10 and 12, 2004
Problem 3.8 can be solved in at least two ways. One approach is to write a loop that computes the compound interest from years 1 through N and then prints the final result. A second approach would compute the result directly via the Math.pow() method. In Problem 3.9 you will need to use both a loop -- for or while will both work -- and a branching construct to compute the increment of the water flow, as defined by equation (3.17).
For each problem, hand in a copy of your program source code and a script file showing the I/O of typical program runs.
Due date: November 17, 9am.
For example, JavaView is a 3D geometry viewer and a mathematical visualization software. The web-integration allows display of 3D geometries and interactive geometry experiments in any HTML document on the internet.
Week 12: November 15, 17 and 19, 2004
Week 13: November 22 and 24, 2004
Week 13: November 29. December 1 and 3. 2004
Question 5.1. Write a Java Program to solve Problem 3.11. You will need to evaluate the Horner's rule and geometic summation formulae using complext number arithmetic -- these details can be computed with the source code file Complex.java .
To help you get started I have written the first part of the geometric series program ... please download GeometricSeries.java and fill in the blocks of code that are missing.
Question 5.2. Download the files Vector.java , Node.java , Edge.java and Triangle.java . Fill in the missing details in the Triangle class.
Question 5.3. Download the source code files PolygonGUI.java and PolygonAnalysis.java , and polygon.txt , a text file containing the (x,y) coordinates for the polygon vertices.
Write a suitable "html" file to run the applet. Extend the capability of the applet so that it will compute and draw the principal axes....we will cover the relevant theory in class. As a starting point, you will need to compute I_xx, I_yy and I_xy. See equations 12.8 and 12.9 in the "computation of engineering properties" section of the red book.
What to hand in. For questions 5.1 and 5.2, hand in a copy of your java source code and a script file showing I/O for a working program. For Problem 5.3, hand in the java source code and a screendump of the polygon gui showing the centroid, properties, and the principal axes!
Due date. Dec. 10, 9am (no extensions).
Week 14: December 7, 9 and 11. 2004
The block of code
// Transform graphics coordinate system ....
AffineTransform at = new AffineTransform();
at.translate( 20, getHeight() - 20 );
at.scale( 1, -1);
transforms the graphics coordinate system from the top left-hand corner of the canvas to the coordinate (20,20) pixels measured from bottom left-hand corner, and then flips the y axis.
Notice that Ixx, Iyy and Ixy are computed about the x- and y- axes. But the principal axes calculation uses these quantities computed about the centroid. The "axes" and "centroid" moments of inertia are related by the parallel axes theorem, namely:
Iyy (axes) = Iyy (centroid) + x^2 A
Ixx (axes) = Ixx (centroid) + y^2 A
Ixy (axes) = Ixy (centroid) + x*y A
Here "x" and "y" are the x- and y- coordinates of the polygon centroid and "A" is the polygon area.
When the contents of polygon.txt are:
1.0 1.0 1.0 5.0 5.0 5.0 5.0 3.0 4.0 3.0 3.0 2.0 3.0 1.0
the textual output generated by "my version" of the program is:
1.0 1.0 1.0 5.0 5.0 5.0 5.0 3.0 4.0 3.0 3.0 2.0 3.0 1.0 fIxxCentroid = 14.907776 fIyyCentroid = 14.9077835 fIxyCentroid = 5.133896 dAngle (rad) = -1.5707955837534795
You should find that the principal axes is oriented at a 45 degree angle, which happens to be parallel to the axis of symmetry in the polygon.
Final Exam: December 16, 8.00am-10.00am. Open book and open notes. There are three questions for a total of 80 points. The first is on object-oriented program development and a few basic things about Java. Two and three are Java programs followed by multi-part questions (just like midterm 2).
Developed in August 2004 by Mark Austin
Copyright © 2004, Department of Civil and Environmental Engineering,
University of Maryland