Computational Thinking Jeannette M. Wing Assistant Director Computer and Information Science and Engineering Directorate National Science Foundation and President’s Professor of Computer Science Carnegie Mellon University GIScience 2008, Park City, UT 24 September 2008

2CT&TCJeannette M. Wing My Grand Vision for the Field Computational thinking will be a fundamental skill used by everyone in the world by the middle of the 21 st Century. –Just like reading, writing, and arithmetic. –Incestuous: Computing and computers wll enable the spread of computational thinking. –In research: scientists, engineers, …, historians, artists –In education: K-12 students and teachers, undergrads, … J.M. Wing, “Computational Thinking,” CACM Viewpoint, March 2006, pp Paper off CISE AC website; paper and talks off

3CT&TCJeannette M. Wing The First A to Computational Thinking Abstractions are our “mental” tools The abstraction process includes –Choosing the right abstractions –Operating simultaneously at multiple layers of abstraction –Defining the relationships the between layers

4CT&TCJeannette M. Wing The Second A to Computational Thinking The power of our “mental” tools is amplified by our “metal” tools. Automation is mechanizing our abstractions, abstraction layers, and their relationships –Mechanization is possible due to precise and exacting notations and models –There is some “computer” below (human or machine, virtual or physical)

5CT&TCJeannette M. Wing Two A’s to C.T. Combined Computing is the automation of our abstractions –They give us the audacity and ability to scale. Computational thinking –choosing the right abstractions, etc. –choosing the right “computer” for the task

6CT&TCJeannette M. Wing Research Implications

7CT&TCJeannette M. Wing CT in Other Sciences, Math, and Engineering Biology - Shotgun algorithm expedites sequencing of human genome - DNA sequences are strings in a language - Protein structures can be modeled as knots - Protein kinetics can be modeled as computational processes - Cells as a self-regulatory system are like electronic circuits Credit: Wikipedia Brain Science - Modeling the brain as a computer - Vision as a feedback loop - Analyzing fMRI data with machine learning Credit: LiveScience

8CT&TCJeannette M. Wing CT in Other Sciences, Math, and Engineering Geology - Modeling the earth’s surface to the sun, from the inner core to the surface - Abstraction boundaries and hierarchies of complexity model the earth and our atmosphere Credit: NASA Credit: University of Minnesota Chemistry [Madden, Fellow of Royal Society of Edinburgh] - Atomistic calculations are used to explore chemical phenomena - Optimization and searching algorithms identify best chemicals for improving reaction conditions to improve yields

9CT&TCJeannette M. Wing CT in Other Sciences, Math, and Engineering Mathematics - Discovering E8 Lie Group: 18 mathematicians, 4 years and 77 hours of supercomputer time (200 billion numbers). Profound implications for physics (string theory) - Four-color theorem proof Credit: Wikipedia Astronomy - Sloan Digital Sky Server brings a telescope to every child - KD-trees help astronomers analyze very large multi-dimensional datasets Credit: SDSS Engineering (electrical, civil, mechanical, aero & astro,…) - Calculating higher order terms implies more precision, which implies reducing weight, waste, costs in fabrication - Boeing 777 tested via computer simulation alone, not in a wind tunnel Credit: Boeing

10CT&TCJeannette M. Wing CT for Society Economics - Automated mechanism design underlies electronic commerce, e.g., ad placement, on-line auctions, kidney exchange - Internet marketplace requires revisiting Nash equilibria model Social Sciences - Social networks explain phenomena such as MySpace, YouTube - Statistical machine learning is used for recommendation and reputation services, e.g., Netflix, affinity card

11CT&TCJeannette M. Wing CT for Society Law - Stanford CL approaches include AI, temporal logic, state machines, process algebras, petri nets - POIROT Project on fraud investigation is creating a detailed ontology of European law - Sherlock Project on crime scene investigation Medicine - Robotic surgery - Electronic health records require privacy technologies - Scientific visualization enables virtual colonoscopy Credit: University of Utah Humanities - What do you do with a million books? Nat’l Endowment for the Humanities Inst of Museum and Library Services

12CT&TCJeannette M. Wing CT for Society Entertainment - Games - Movies - Dreamworks uses HP data center to renderShrek and Madagascar - Lucas Films uses 2000-node data center to produce Pirates of the Caribbean. Credit: Dreamworks SKG Credit: Carnegie Mellon University Sports - Lance Armstrong’s cycling computer tracks man and machine statistics - Synergy Sports analyzes digital videos NBA games Credit: Wikipedia Arts - Art (e.g., Robotticelli) - Drama - Music - Photography Credit: Christian Moeller

13CT&TCJeannette M. Wing Educational Implications

14CT&TCJeannette M. Wing Pre-K to Grey K-6, 7-9, Undergraduate courses –Freshmen year “Ways to Think Like a Computer Scientist” aka Principles of Computing –Upper-level courses Graduate-level courses –Computational arts and sciences E.g., entertainment technology, computational linguistics, …, computational finance, …, computational biology, computational astrophysics Post-graduate –Executive and continuing education, senior citizens –Teachers, not just students

15CT&TCJeannette M. Wing Question and Challenge to Community What are effective ways of learning (teaching) computational thinking by (to) children? - What concepts can students best learn when? What should we teach when? What is our analogy to numbers in K, algebra in 7, and calculus in 12? - We uniquely also should ask how best to integrate The Computer with learning and teaching the concepts.

16CT&TCJeannette M. Wing Example Concepts

17CT&TCJeannette M. Wing Recursion: Towers of Hanoi Goal: Transfer the entire tower to one of the other pegs, moving only one disk at a time and never a larger one onto a smaller.

18CT&TCJeannette M. Wing Data Abstraction and Representation stack tree (upside down) queue array and pointer representation invariant Credit: Wikipedia

19CT&TCJeannette M. Wing Composition and Decomposition Credit: The LEGO Group Credit: Meccano

20CT&TCJeannette M. Wing Sorting and Search

21CT&TCJeannette M. Wing Intractability: Traveling Salesman Problem: A traveling salesperson needs to visit n cities. Is there a route of at most d in length? O(n!) n = 16  242 days n = 25  5x10^15 centuries

22CT&TCJeannette M. Wing Undecidability: Tiling Can we tile the entire plane Z 2 ? Example from David Harel

23CT&TCJeannette M. Wing Data as Code and Code as Data unrecognized attachment

24CT&TCJeannette M. Wing Correctness: Avoiding Bugs to Save Money and Lives Now Microsoft uses formal verification. Intel Pentium FPU error Credit: BYTE Magazine Now Intel uses formal verification. Credit: Intel Ariane 5 failure Credit: ESA

25CT&TCJeannette M. Wing Caching locker knapsack home Credit: Wikipedia

26CT&TCJeannette M. Wing Pipelining: Doing Laundry 6 hours to do 4 loads 3.3 hours to do 4 loads

27CT&TCJeannette M. Wing Concurrency: Dining Philosophers Five philosophers sit around a circular table. Each philosopher spends his life alternately thinking and eating. In the centre of the table is a large bowl of spaghetti. A philosopher needs two forks to eat a helping of spaghetti.

28CT&TCJeannette M. Wing Distributed Computing: The Internet Asynchronous communication Failures Speed of light

29CT&TCJeannette M. Wing Distributed Computing: The Internet Asynchronous communication Failures Speed of light

30CT&TCJeannette M. Wing Reach Through NSF

31CT&TCJeannette M. Wing CDI: Cyber-Enabled Discovery and Innovation Paradigm shift –Not just our metal tools (transistors and wires) but also our mental tools (abstractions and methods) It’s about partnerships and transformative research. –To innovate in/innovatively use computational thinking; and –To advance more than one science/engineering discipline. FY08: 1800 Letters of Intent, 1300 Preliminary Proposals, 200 Final Proposals, 36 Awards ~$50M invested by all directorates and offices Computational Thinking for Science and Engineering

32CT&TCJeannette M. Wing Range of Disciplines in CDI Awards Aerospace engineering Atmospheric sciences Biochemistry Biophysics Chemical engineering Communications science and engineering Computer science Geosciences Linguistics Materials engineering Mathematics Mechanical engineering Molecular biology Nanocomputing Neuroscience Robotics Social sciences Statistical physics … advances via Computational Thinking

33CT&TCJeannette M. Wing Range of Societal Issues Addressed Cancer therapy Climate change Environment Visually impaired Water

34CT&TCJeannette M. Wing CISE Educational Programs CPATH –Revisiting undergrad curricula –Enlarge scope to include outreach to K-12 –National Academies workshops on Computational Thinking for Everyone Broadening Participation in Computing –Women, underrepresented minorities, people with disabilities –Alliances and demo projects –Image of computing –Re-envisioning Computer Science AP exam

35CT&TCJeannette M. Wing Spread the Word! Help make computational thinking commonplace To fellow faculty, students, researchers, administrators, teachers, parents, principals, guidance counselors, school boards, teachers’ unions, congressmen, policy makers, …

Thank you!

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