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Scientific Computation What’s the big idea? CS112 Scientific Computation Department of Computer Science Wellesley College 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 Big ideas 1-2 Data visualization and analysis ● Graphical display of data ● Statistical analysis of data ● Fitting functions to data Big ideas 1-3 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 Big ideas 1-4 The sunspot data: How can we determine the length of the sunspot cycle? Big ideas 1-5 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! Big ideas 1-6 Visualizing data Big ideas 1-7 Whodunit? Big ideas 1-8 Create synthetic data and images simultaneous contrast illusion Perceptual experiments: collect data from human subjects, analyze data, implement and test models of human visual processing Big ideas 1-9 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 .... Big ideas 1-10 Searching databases ● What is the average cholesterol level for women in their twenties who exercise at least 30 minutes a day? cholesterol age sex exercise 189 239 178 185 251 165 ... 25 35 28 40 28 22 ... ‘f’ ... 60 ... ‘m’ 30 ‘m’ 15 ‘f’ 40 ‘m’ 25 ‘m’ 15 Big ideas 1-11 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” Big ideas 1-12 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 ● The MathWorks website has many more examples Big ideas 1-13 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 Big ideas 1-14