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Computational Thinking. What is it? Computer Science Unplugged. Computational Thinking (CT) (from Jeannette Wing’s website). Computational thinking will be a fundamental skill used by everyone in the world by the middle of the 21 st Century.
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Computational Thinking What is it?Computer Science Unplugged
Computational Thinking (CT)(from Jeannette Wing’s website) • Computational thinking will be a fundamental skill used by everyone in the world by the middle of the 21st Century. • J.M. Wing, “Computational Thinking,” CACM Viewpoint, March 2006, pp. 33-35. http://www.cs.cmu.edu/~wing/
Examples of CT(from Jeannette Wing’s website) • Determining how difficult a problem is to solve. Thinking recursively. • Choosing an appropriate representation for data to simplify the solution to problems. • Reformulating a seemingly difficult problem into one which we know how to solve. • Using abstraction and decomposition in tackling a large complex task. • Using the difficulty of solving hard AI problems to foil computing agents.
Examples of CT in daily life(from Jeannette Wing’s website) • Sorting important documents. • Choosing a line at the supermarket. (queuing and scheduling) • Putting things in your child’s knapsack for the day. (caching) • Running errands (Traveling salesperson) • Cooking dinner or washing loads of laundry (parallel processing/pipelining)
CT in STEM(from Jeannette Wing’s website) • Biology • Shotgun algorithm expedites sequencing of human genome • DNA sequences are strings in a language • Brain Science • Analyzing fMRI data with machine learning algorithms • Chemistry • Optimization and searching algorithms identify best chemicals for improving reaction conditions to improve yields
CT in STEM(from Jeannette Wing’s website) • Earth Science • Modeling the earth or the sun: inner core, surface, atmosphere • Astronomy • Sloan Digital Sky Server brings a telescope to every child • Mathematics • Discovering E8 Lie Group: Profound implications for physics (string theory) • Engineering • Boeing 777 tested via computer simulation alone, not in a wind tunnel
Computational ThinkingAn Operational Definition for K-12 Computational thinking (CT) is a problem-solving process that includes (but is not limited to) the following characteristics: • Formulating problems in a way that enables us to use a computer and other tools to help solve them. • Logically organizing and analyzing data • Representing data through abstractions such as models and simulations • Automating solutions through algorithmic thinking (a series of ordered steps) • Identifying, analyzing, and implementing possible solutions with the goal of achieving the most efficient and effective combination of steps and resources • Generalizing and transferring this problem solving process to a wide variety of problems
Computational ThinkingAn Operational Definition for K-12 These skills are supported and enhanced by a number of dispositions or attitudes that are essential dimensions of CT. These dispositions or attitudes include: • Confidence in dealing with complexity • Persistence in working with difficult problems • Tolerance for ambiguity • The ability to deal with open ended problems • The ability to communicate and work with others to achieve a common goal or solution
Count The Dots • Data in computers is stored and transmitted as a series of zeros and ones. • How can we represent words and numbers using just these two symbols?
Count The Dots • Letters are represented in computers in binary also. • Blank 0 000002 A 1 000012 B 2 000102 C 3 000112 ... Z 26 110102
Count The Dots 01001 00011 00101 00000 00011 10010 00101 00001 01101 blank 0 A 1 B 2 C 3 D 4 E 5 F 6 G 7 H 8 I 9 J 10 K 11 L 12 M 13 N 14 O 15 P 16 Q 17 R 18 S 19 T 20 U 21 V 22 W 23 X 24 Y 25 Z 26 I C E _ C R E A M
Color By Numbers • Computer screens are divided up into a grid of small dots called pixels (picture elements). In a black and white picture, each pixel is either black or white. • Computers store drawings, photographs and other pictures using only numbers. • The following activity demonstrates how a computer image can be stored efficiently.
Color By Numbers • The letter a has been magnified to show the pixels. When a computer stores a picture, all that it needs to store is which dots are black and which are white. 1,3 4,1 1,4 0,1,3,1 0,1,3,1 1,4
Color By Numbers 6,5,2,3 4,2,5,2,3,1 3,1,9,1,2,1 3,1,9,1,1,1 2,1,11,1 2,1,10,2 2,1,9,1,1,1 2,1,8,1,2,1 2,1,7,1,3,1 1,1,1,1,4,2,3,1 0,1,2,1,2,2,5,1 0,1,3,2,5,2 1,3,2,5
Color By Numbers • This technique is called run-length encoding. • Fax transmission • Compression of images • Color encoding • Use two numbers per run • First number is how many pixels as before • Second number is what color (1=red, 2=green, ...)
Information Theory • How much information is there in a book? Is there more information in a telephone book, or in Harry Potter and the Deathly Hallows? • If we can measure this, we can estimate how much space is needed to store the information. • Can you read the following sentence? Ths sntnc hs th vwls mssng.
Twenty Guesses • I am thinking of a number between0 and 127. • You may only ask questions that have a "yes" or "no" answer. • For each question, you will lose one piece of candy. • Once you guess the number correctly, you can keep whatever candy remains.
Twenty Guesses • To pick a number between 0 and 127, you only need 7 guesses. • Always shoot for the middle number of the range and eliminate half the possibilities! • This concept is called binary search. • If the number was between 0 and 1,023, you would only need 3 additional guesses. • You can guess a number between 0 and 1,048,575 in only 20 guesses!
