1. CS112 Scientific Computation Department of Computer Science Wellesley College Scientific Computation What’s the big idea?

2. Big ideas1-2 A scientific toolbox ● A computer is a general-purpose tool for processing information ● Main goal of CS112 is to learn how to build your own specialized tools for scientific work ● Your tools will be computer programs written in MATLAB

3. Big ideas1-3 Data visualization and analysis ● Graphical display of data ● Statistical analysis of data ● Fitting functions to data

4. Big ideas1-4 Sunspots ● Discovered independently by Christoph Scheiner (1610) and Galileo (1613) ● Indicate disturbances in the sun’s magnetic field ● The number of sunspots varies over time in a cyclical way ● Sunspot Cycle* discovered by Samuel Schwabe (1843) * There is some connection between sunspots and extreme weather

5. Big ideas1-5 The sunspot data: How can we determine the length of the sunspot cycle?

6. Big ideas1-6 The length of the sunspot cycle: ~ 12 years Note: virtually no sunspot activity in the years 1650-1700 (Europe’s mini ice-age) and we’re currently in a low spot in the cycle!

7. Big ideas1-7 Visualizing data

8. Big ideas1-8 Whodunit?

9. Big ideas1-9 Create synthetic data and images Perceptual experiments: collect data from human subjects, analyze data, implement and test models of human visual processing simultaneous contrast illusion

10. Big ideas1-10 Ribonucleic acid ● An RNA molecule is a sequence of nucleotides drawn from Adenine (A), Guanine (G), Cytosine (C), and Uracil (U) ● Three adjacent nucleotides form a triplet called a codon that corresponds to a single amino acid ● You’ll write a MATLAB program that translates a sequence of RNA nucleotides to an amino-acid sequence: UANCUAUCUAUCUUCCGGUC...  Tyr Leu Ser Ile Phe Gln Val....

11. Big ideas1-11 Searching databases ● What is the average cholesterol level for women in their twenties who exercise at least 30 minutes a day? 189 cholesterol 239 178185 251 25 age 35 2840 28 sex exercise 165... 22... ‘m’ ‘f’‘m’ ‘f’ 30 15 4025 15 60

12. Big ideas1-12 Designing GUI’s* ● Graphical User Interfaces simplify communication with our programs by using text boxes, pop-up windows, buttons, menus, check boxes, sliders, etc. ● We’ll use MATLAB’s GUI facilities to build our own interactive programs * Pronounced “gooey”

13. Big ideas1-13 Physical simulation ● Prof. Yue Hu in Physics, together with students Nicole DuRand ‘06 and Christina Miller ‘08, created animations in MATLAB that simulate simple physical systems animations in MATLAB ● The MathWorks website has many more examplesMathWorks website

14. Big ideas1-14 Credits Plotting emissions test data: http://www.mathworks.com/demos/matlab/... analyzing-data-overview-matlab-video-demonstration.html Sunspot data and image: http://www.macalester.edu/~kaplan http://web.me.com/uriarte/Earths_Climate/... Sunspots_and_solar_cycles_files/sunspot032901.gif Visualization examples: http://scv.bu.edu/SCV/vizgal http://visualizationlab.vassar.edu/instvishome MATLAB Help: Visualizing MRI data http://www.mathworks.com/products/matlab/demos.html