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Social Networks as a Foundation for Computer Science

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as a Foundation for Computer Science Owen Astrachan http://www.cs.duke.edu/~ola – PowerPoint PPT presentation

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Title: Social Networks as a Foundation for Computer Science


1
Social Networksas a Foundationfor Computer
Science
  • Owen Astrachan
  • http//www.cs.duke.edu/ola

2
Where are we going Questions
  • What should our concerns be for those choosing to
    major in Computer Science?
  • courses, research, jobs,
  • Should we be concerned by the precipitous decline
    in those taking our courses or majoring or ?
  • majors, technical students, non-technical
  • What can we do to ensure the ongoing success of
    our academic discipline?
  • Look inward, look to others

3
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4
WWDD?
5
Questions
  • If you gotta ask, youll never know
  • Louis Armstrong Whats jazz?
  • If you gotta ask, you aint got it
  • Fats Waller Whats rhythm?
  • What
    questions did you ask in school
  • today?
  • Arno Penzias via Isaac Isadore Rabi

6
Questions and Answers
  • Judge a man by his questions rather than by his
    answers

  • Voltaire

7
Computer Science
  • What is the foundation of computer science?
  • Historically, now, in the future
  • What changes are here, on the horizon?
  • From theory to practice to education
  • Can we relate to what and how students learn?
  • Is every generation different, the same,

8
History and Computer Science
  • Those who cannot remember the past are condemned
    to repeat it.
  • Dont know much about history, dont know much
    about biology, dont know much about a science
    book

9
Who, when?
  • No stretching is required to envision computer
    consoles installed in every home.
  • Everyone will have better access to the Library
    of Congress than the librarian himself now has.
  • Full reports on current events, whether baseball
    scores, the smog index in Los Angeles or the
    minutes of the 178th Korean Truce Commission will
    be available for the asking.
  • John, McCarthy, Information, Chapter 1, 1966

10
You win some, you lose some
  • People will soon become discontented with the
    canned programs available they will want to
    write their own. The ability to write a computer
    program will be as widespread as the ability to
    drive a car.
  • Not knowing how to program will be like living in
    a house full of servants and not speaking their
    language.
  • Many people can write simple programs after an
    hour or two of instruction. Programming is far
    easier to learn than a foreign language or
    algebra.

11
Then and Now
kentlew.com
  • Bailey, SIGCSE 1972
  • It is remarkable that the majority of students
    can indeed handle fairly complex (Fortran) I/O by
    the end of the first six lessons, even though
    they have not actually been formally taught how
    to do it.
  • Roberts et al, SIGCSE 2006
  • The problem most often cited by those attempting
    to teach Java to novices is the lack of a simple
    input mechanism,

12
Teaching Compsci in 1984
  • 64K memory, 128K extended
  • 8-bit, 1 Mhz 6502 processor
  • 5Mb drive 3500
  • UCSD Pascal gt100
  • Owen's machine 3000
  • 677.80 in 1984 has 1200 "purchase power" in
    2003
  • http//eh.net/hmit/ppowerusd/

13
Typical machine in 2006?
  • 1 Gb memory
  • 3 GHz, 32-bit chip
  • Cache,
  • 160 Gb disk
  • Lots of free resources
  • Good academic pricing
  • Under 600 (priced 6/19/06)

14
What has changed in 20 years?
  • Machines
  • Characteristics and Availability
  • Internet
  • Availability, IM, web, Google,
  • Students
  • Comfort with technology, Expectations

15
The more things change?
  • Assume I took your first course(s) in 1984 and
    understood the concepts so completely that I
    could still get a 100 on the final from 1984 if I
    took it today (e.g., I've been in a cryogenic
    chamber). How would I do on the 2004 final exam?

16
What has changed in Physics?
  • "You'd get a 100 plus or minus sigma. Intro
    classical physics hasn't really changed that much
    over the last 100 years. In graduate level e.g.
    EM or quantum classes I think ditto, although
    sigma would be bigger (and might depend more on
    the instructor variation than on any real
    variation in the material). The main difference
    is, I think, that your chances of GETTING 100 now
    would be much higher."
  • Rob Brown,
  • Poohbah of Physics Instruction

17
What has changed in Biology?
  • "The basic principles and concepts of biology
    haven't changed much in 20 years.  What has
    changed relates to specific content, and in this
    arena the changes have been enormous.  20 years
    ago, we barely knew how to sequence DNA today
    information of this kind has had a major impact
    on just about every topic in the biological
    sciences.  Thus, some questions on an exam today
    would address topics that would be completely
    unfamiliar to a 1984 time-traveller. "
  • Greg Wray,
  • Director of Undergraduate Studies, Biology

18
What has changed in Economics?
  • " we now cover material that was only introduced
    in an advanced or intermediate course in 1984. In
    1984 we spent the bulk of the time dealing with
    the Keynesian model and virtually no dialogue
    about supply side policies. Now the Keynesian
    stuff is a small subset of a much broader
    exposure to Aggregate demand and supply Also
    there is more international coverage now - as
    opposed to 20 years ago for obvious reasons."
  • Lori Leachman,
  • Director of Undergraduate Studies, Economics

19
What has changed in Calculus?
  • We have two varieties of calculus courses, the
    lab courses and the traditional ...  The latter
    two have not changed significantly in decades,
    and I think that a student who fared well on the
    1984 exam in those courses would do well today,
    and vice versa.
  • In the lab courses You would ace about half the
    exam.  The other half would be unfamiliar to
    you.  For example, you would probably not know
    how to answer a problem on modeling a set of
    data, creating an approximation using Euler's
    method, interpreting derivatives in the context
    of applications in other fields, or giving
    explanations of ideas
  • Lewis Blake,
  • Supervisor of First-year Instruction

20
Changes in Computer Science?
21
Changing CS? Rock, Hard place
  • If Computer Science has changed drastically is it
    to keep up with fads and stylistic changes or
    because of fundamental changes in the discipline?
  • Are we leveraging the technological and
    intellectual resources at our disposal
  • If we havent changed, is it because of a solid
    bedrock of principles that endures? Or because
    were lazy, good-for-nothing,

22
1985, AP Computer Science, Q2
  • Write a procedure Compact that eliminates all
    elements with value 0 from its argument, a list.
    Compact leaves the order of the other elements
    unchanged. For example, if list is
  • (0,9,7,0,0,23,4,0)
  • When the procedure is called, it should be
  • (9,7,23,4)
  • After the procedure executes. All local
    variables should be scalar.
  • (declaration for Pascal record with array and
    count)

23
2004, AP, Question 1
  • public class WordList
  • private ArrayList myList
  • public void removeWordsOfLength(int len)
  • // you write this

24
Details of Question Revisited
  • Write the WordList method removeWordsOfLength.
    Method removeWordsOfLength removes all words
    from the WordList that are exactly len lettters
    long leaving the order of the remaining words
    unchanged.
  • For example assume that the instance variable
    myList of the WordList animals contains the
    following
  • cat, mouse, frog, dog, dog
  • After the call animals.removeWordsOfLength(3)
  • mouse, frog

25
What is CS? Who wants to study it? Why do they
want to?
26
What is Computer Science?
What is the central core of the subject? What
is it that distinguishes it from the separate
subjects with which it is related?
  • What is the linking thread which gathers these
    disparate branches into a single discipline? My
    answer to these questions is simple --- it is the
    art of programming a computer.

27
Is this Computer Science?
  • public static void stuff(int n)
  • doit(n,0,1,2)
  • public static void
  • doit(int n,int f, int t, int a)
  • if (n 1) move(n,f,t)
  • else
  • doit(n-1,f,a,t)
  • move(n,f,t)
  • doit(n-1,a,t,f)

28
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29
NYTimes in 1984
30
What is CS? Why study it?
  • Do we have Physics (Math, ) Envy?
  • It's hard for voice over Internet Protocol or
    e-commerce to compete with finding the age of the
    universe, Peter Lee, CMU
  • Does familiarity breed contempt?
  • What was different in 1984 than today?

31
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32
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33
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34
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35
COHFE
  • Amherst College, Barnard College, Brown
    University, Bryn Mawr College, Carleton College,
    Columbia University, Cornell University,
    Dartmouth College, Duke University, Georgetown
    University, Harvard University, Johns Hopkins
    University, Massachusetts Institute of
    Technology, Mount Holyoke College, Northwestern
    University, Oberlin College, Pomona College,
    Princeton University, Rice University, Smith
    College, Stanford University, Swarthmore College,
    Trinity College, University of Chicago,
    University of Pennsylvania, University of
    Rochester, Washington University in St. Louis,
    Wellesley College, Wesleyan University, Williams
    College, Yale University

36
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37
Whats wrong with this picture?
  • Why is the first year different from all other
    years?

38
Algorithm Arch OS AI
CMU
MIT
Stanford
Berkeley
UIUC
Cornell
UTexas
UW
Cal Tech
Wisc
G. Tech
Maryland
Brown
UCLA
Michigan
UNC
Penn
Duke
Harvard
Purdue
UCSD
39
Books and Approaches Used
40
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41
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42
If you dont take a course in CS, you wont major
in it.
  • Why is the first year different from all other
    years?

43
Who's going to College?
44
Who's going to College?
45
Who's going to College?
46
How do we get Studentsinto the Compsci Tent?
  • Why is the first year different from all other
    years?

47
Interdisciplinary minors
  • At Duke it is difficult to double major in
    sciences
  • Too many requirements, 17 courses in biology
  • Students are interested in credentials
  • No business major/minor, certificate program
    (requires intro, capstone, six courses)
  • Minor requires five courses, double counting ok
  • Three courses in CS, two in econ or biology
  • From gene to social networks, data mining,

48
Genome Revolution Focus Course
  • Arts in Contemporay Society, Exploring the Mind,
    Evolution and Humankind, 20th Century Europe,
    Visions of Freedom, The Genome Revolution and its
    Impact on Society,
  • Three of four courses, one writing, two others.
    Interdisciplinary 0.5 credit seminar P/F
  • Seminars, students live in same dorm
  • 600 out of 1600 in FOCUS course
  • For Genome, 80 applicants for 30 slots, 65 women
  • In CS Genomics course 8 women, 9 men

49
Simple examples
  • Given strand of DNA, calculate CG ratio
  • Potential source of proteins CGGATTATC
  • Given protein HLVWW calculate number of
    different DNA strands that could code for it
  • 64 codons, 20 amino acids
  • Find heaviest protein in array of proteins
  • Given atomic mass of amino acids
  • Interpret ORF data from NCBI website

50
From Algorithms to Objects
  • Read DNA assumed to be in 5 to 3 orientation
  • Use BioJava to read via http
  • Construct reverse complement (3 to 5)
  • From CAATT produce AATTG
  • How big is the human genome?
  • Runtime of algorithm O(1)

51
Computer Science is filled with real-world
examples.
  • Why is the first year different from all other
    years?

52
A picture is worth
53
A thousand words
  • Write class Cat that says 'meow'
  • Write LoudDog that says 'bark-bark' when Dog
  • says 'bark'

54
How do we teach CS?
55
Putting it all together
  • we conclude that students are not given
    sufficient instruction in how to "put the pieces
    together." Focusing explicitly on specific
    strategies for carrying out the coordination and
    integration of the goals and plans that underlie
    program code may help to reverse this trend.
  • Sporher and Soloway,
  • Novice mistakes Are the folks wisdoms correct?
    Studying the Novice Programmer, 1989

56
Changing Data into Knowledge
  • We provide an unjust education if we do not
    give every student the maximum opportunity for
    learning. Depending on their natural abilities,
    imbalance in education deprives some students of
    learning more than others. Those who are
    naturally more creative, or have better memories,
    or are more reflective, or are more active have
    different opportunities if we do not provide
    balance. That is unjust.
  • James Zull The Art of Changing the Brain

57
Teaching as
  • English is not history and history is not
    science and science is not art and art is not
    music, and art and music are minor subjects and
    English, history and science major subjects, and
    a subject is something you 'take' and when you
    have taken it, you have 'had' it, and if you have
    'had' it, you are immune and need not take it
    again." (The Vaccination Theory of Education?)

58
Back to the Future
  • How will we know when we get there?

59
A Future for Computer Science?
60
What does the Internet look like?
61
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62
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63
Is there a Science of Networks?
  • From Erdos numbers to random graphs to Internet
  • From FOAF to Selfish Routing
  • Modeling, simulation, and hypotheses
  • Computer Science?
  • From the facebook to tomogravity
  • How do we model networks, measure them?
  • What mathematics is necessary?
  • Will the real-world intrude?

64
Network Models (Barabasi)
  • Differences between Internet, Kazaa, Chord
  • Building, modeling, predicting
  • Static networks, Dynamic networks
  • Modeling and simulation
  • Random and Scale-free
  • Implications?
  • Structure and Evolution
  • Modeling via Touchgraph

65
Web-based social networks
  • http//trust.mindswap.org
  • Myspace 73,000,000
  • Passion.com 23,000,000
  • Friendster 21,000,000
  • Black Planet 17,000,000
  • Facebook 8,000,000
  • Whos using these, what are they doing, how often
    are they doing it, why are they doing it?

66
Golbecks Criteria
  • Accessible over the web via a browser
  • What about the new MOG.com?
  • Users explicitly state relationships
  • Not mined or inferred
  • Relationships visible and browsable by others
  • Reasons?
  • Support for users to make connections
  • Simple HTML pages dont suffice

67
CSE 112, Networked Life (UPenn)
  • Find the person in Facebook with the most friends
  • Document your process
  • Find the person with the fewest friends
  • What does this mean?
  • Search for profiles with some phrase that yields
    30-100 matches
  • Graph degrees/friends, what is distribution?

68
What can we do with real data?
  • How do we find a graphs diameter?
  • This is the maximal shortest path between any
    pair of vertices
  • Can we do this in big graphs?
  • What is the center of a graph?
  • From rumor mills to terrorists
  • How is this related to diameter?
  • Demo GUESS (as augmented at Duke)
  • IM data, Audioscrobbler data

69
My recommendations at Amazon
70
And again
71
Finally,
72
From Pigou to Braess
  • Roughgarden terminology
  • Selfish Routing
  • Cost as measure of social welfare
  • Non-cooperative agents
  • Nash flows
  • Optimality
  • Game Theoretic

SCH
73
Alan Kay
  • "Simple things should be simple. Complex things
    should be possible".
  • "The best way to predict the future is to invent
    it"
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