Missing Image
  Missing Image
  Missing Image
  Missing Image
  Missing Image

Networked and Social Systems Engineering (NETS) 112
Fall 2016
Tuesdays and Thursdays 10:30-12, Berger Auditorium, Skirkanich Hall
Prof. Michael Kearns

Jump to the course schedule.


  • What science underlies companies like Facebook and Twitter?
  • What are the economics of email spam?
  • How much is revealed by who you call, text, or friend?
  • Why do some social networking services take off, and others die?
  • What do game theory and the Paris subway have to do with Internet routing?
  • How does Google find what you're looking for... and exactly how do they make money doing so?
  • How might a social network influence election outcomes?
  • What problems can be solved by crowdsourcing?
  • How does your position in a social network (dis)advantage you?

    Networked Life looks at how our world is connected -- socially, strategically and technologically -- and why it matters.

    The answers to the questions above are related. They have been the subject of a fascinating intersection of disciplines, including computer science, physics, psychology, sociology, mathematics, economics and finance. Researchers from these areas all strive to quantify and explain the growing complexity and connectivity of the world around us, and they have begun to develop a rich new science along the way.

    Networked Life will explore recent scientific efforts to explain social, economic and technological structures -- and the way these structures interact -- on many different scales, from the behavior of individuals or small groups to that of complex networks such as the Internet and the global economy.

    This course covers computer science topics and other material that is mathematical, but all material will be presented in a way that is accessible to an educated audience with or without a strong technical background. The course is open to all majors and all levels, and is taught accordingly. There will be ample opportunities for those of a quantitative bent to dig deeper into the topics we examine. The majority of the course is grounded in scientific and mathematical findings of the past two decades or less (often much less).

    Fall 2016 is the thirteenth offering of Networked Life. You can get a detailed sense for the course by visiting the extensive course web pages from past years:
    [Fall 2015]   [Fall 2014]   [Fall 2013]   [Fall 2012]   [Fall 2011; hosted by now-defunct startup so lost forever]   [Spring 2010]   [Spring 2009]   [Spring 2008]   [Spring 2007]   [Spring 2006]   [Spring 2005]   [Spring 2004]

    There is also a greatly condensed version of this class offered to the general public as part of the online education platform Coursera. While the Coursera version is not being offered online this semester, we will make the corresponding videos available in the Penn offering.

    Networked Life is the flagship course for Penn Engineering's recently launched Networked and Social Systems Engineering (NETS) program. Throughout the course we will foreshadow material that is covered in greater depth in later NETS program courses.


    The following book is recommended but not required; it is easy and entertaining reading, and provides a high-level introduction to some course themes:

  • The Tipping Point, by Malcolm Gladwell. Paperback. Little Brown & Company, 2000.

    The following two books are required; we will read most but not all of them:

  • Six Degrees: The Science of a Connected Age, by Duncan J. Watts. Paperback. W.W. Norton, 2003.
  • Micromotives and Macrobehavior, by Thomas C. Schelling. Paperback. W.W. Norton, 1978.

    In addition to readings from these texts, there will be frequent articles from the recent scientific and popular literature that will be provided directly on this web page at the appropriate points in the syllabus.


    Prof. Michael Kearns, Course Instructor
    Levine Hall 509
    Office hours: Tuesdays 12-1 PM (right after lecture), or by appointment

    Adel Boyarsky, Teaching Assistant
    Office hours: Mondays 12-1 PM, bump space next to 502 Levine

    Mary Peyton Sanford, Teaching Assistant
    Office hours: Sundays 3:30-4:30 PM, bump space next to 502 Levine

    Brad Thompson, Teaching Assistant
    Office hours: Wednesdays 11AM-12, bump space next to 502 Levine


    Attendance at the main lectures is considered mandatory for all enrolled students. They are held Tuesdays and Thursdays 10:30-12 in Berger Auditorium of Skirkanich Hall. There are no recitations for the course.


    Networked Life has no formal prerequisites, and is meant to be accessible to a broad range of students across SEAS, the College, and Wharton. No computer programming background is required, but students should be comfortable using computers and the Web, and accessing resources on the Internet.

    The course is open to all majors and all levels.


  • Networked Life is one of the courses satisfying the College of Arts and Sciences' Quantitative Data Analysis Requirement.
  • Networked Life can be counted as an official Engineering Elective course in CIS and SEAS.
  • Networked Life can be counted for credit in the Philosophy, Politics and Economics (PPE) and Science, Technology and Society (STSC) programs. Check with your academic advisor in these programs to confirm exactly how you can count the course.


    The main lectures for Networked Life will be in fairly traditional format, including class participation, discussion, and communal in-class experiments. PDF slides for all lectures will be provided, usually at least slightly in advance of the lecture itself.

    There will be two or three homework assignments. These will include simple quantitative exercises, as well as essay questions, computer and web exercises. Collaboration on the homeworks is not permitted.

    There will be a midterm, and a final exam. We may have a quiz or two as well.

    It is anticipated that the homeworks/quizzes, midterm and final will each count for approximately a third of the overall grade.

    Students are encouraged to bring articles, demos, web pages, news events, etc. that are relevant to course topics to the attention of Prof. Kearns. Extra credit will be given if the suggested material is used in the course (see the "Fourth Column" below).


    Except for occasional hard-copy handouts distributed in lectures, all of the material for the course will be posted in the table below. Lecture slides, reading and homework assignments, in-class and out-of-class experiments, due dates, exam information, etc. will all be provided below. The materials posted are initially those from the last offering of the class, and will be gradually updated and possibly altered as we progress through the course. New materials and topics may be added as well. Reading and working ahead are encouraged, just be aware that things may change a bit as we proceed. It is every student's responsibility to monitor this schedule closely and regularly.

    In the assigned readings below, "Watts" and "Schelling" refer to the two required texts cited above. Other readings will be directly provided as links to PDF documents. Unless specified otherwise, you should generally try to complete the assigned reading during roughly the period spanned by the dates given in the same row of the table.

    The lecture slides are all in PDF format, but they may often contain links to documents in other formats, including Postscript, JPEG, video, etc. In order to view all of the linked content you may need to be using a computer with viewers installed for these formats. Note that since slides are revised shortly in advance of each lecture date, links to future decks may not yet be active.

    In the "DATES" column of the table below, our current place in the schedule will be highlighted in red.

    "THE FOURTH COLUMN" will be used to put links to class-related materials from the popular media, the web, etc. Extra credit will be provided to those who send me such material if it is used.

    Tu Aug 30
    Course Introduction and Overview
    [PDF] [PPT]
    (Rev. 8/29)

    Here is the Coursera course overview video.

    Here is a document containing a brief background survey and our second communal social experiment. Please print them out, complete them (which should only take a few minutes), and return them at the start of the second lecture (Tue Sep 1), as we will analyze the results of the social experiment on the fly in class.

    As sample Fourth Column material, A contagion oldie but goodie.

    Th Sep 1
    Tu Sep 6
    Th Sep 8
    Structural Properties of Networks: Introduction
    [PDF] [PPT]
    (Rev. 9/8)

    Please read this lightweight introduction to some course concepts via a network analysis of squash matches.

    Link to the Erdos Number Project.

    Here are two Coursera videos that are related to this set of lectures:

    What is a Network?

    The Erdos Number Project

    TA office hours have been announced, see Course Personnel section above.

    From TA Brad Thompson, and apropos of my comments in the first lecture about phantom traffic jams.

    While we're on the topic of the sociology of mathematical collaboration, First-to-Field-Agent honors go to Colin Roberts for pointing out this recent article on the mega-ancestors of math.

    Tu Sep 13
    Th Sep 15
    Tu Sep 20
    Th Sep 22
    Contagion in Networks
    [PDF] [PPT]
    (Rev. 9/5)
    The following three assigned papers will be discussed in lecture. At a minimum you should know what the main results are, but try to understand as much as you can.

    Can Cascades be Predicted? Cheng, Adamic, Dow, Kleinberg, Leskovec.

    Structural Diversity in Social Contagion. Ugander, Backstrom, Marlow, Kleinberg.

    The Structural Virality of Online Diffusion. Goel, Anderson, Hofman, Watts.

    Here is a link where you can download NetLogo, a very nice app with many scientific simulations and models. Throughout the term we'll be examining several of the simulations under the Networks section, including this one, which we'll play around in class with.

    Here is a Coursera video related to this topic:

    Contagion in Networks

    From F.A. Enoch Solano, an amusing introduction to Internet contagion.

    Th Sep 22
    Tu Sep 27
    Th Sep 29
    Navigation in Networks
    [PDF] [PPT]
    (Rev. 9/20)

    During this set of lectures, we will discuss the following five articles.

    ``An Experimental Study of the Small World Problem'', by J. Travers and S. Milgram.

    ``An Experimental Study of Search in Global Social Networks'', by P. Dodds, R. Muhamad, and D. Watts.

    Navigation in a Small World, Kleinberg.

    Identity and Search in Social Networks, Watts, Dodds, Newman.

    The Scaling Laws of Human Travel, Brockmann, Hufnagel, Geisel.

    There are two Coursera videos associated with this lecture:

    Navigation in (Social) Networks

    Navigation in Networks, Revisited

    Here is Homework 1, which is due at the start of lecture on Thursday September 29 in hard-copy format.

    The date of the midterm will be Thursday, October 20.

    Tu Oct 4
    Th Oct 6
    How Do Real Networks Look?
    [PDF] [PPT]
    (Rev. 10/4)

    For these lectures and the next set, you should read Chapters 2, 3 and 4 in "Six Degrees". (I recommend simply reading the book in its entirety, but will not require it.)

    We will also be discussing the following paper:

    Four Degrees of Separation. Backstrom et al, 2012.

    Here are Coursera videos associated with this set of lectures:

    How Do Real Networks Look? I. Heavy Tails

    How Do Real Networks Look? II. Small Diameter

    How Do Real Networks Look? III. Clustering of Connectivity


    Tu Oct 11
    Th Oct 13
    Models of Network Formation
    [PDF]   [PPT]
    (Rev. 10/4)

    Coursera videos associated with these lectures:

    Models of Network Formation I. The Erdos-Renyi Model

    Models of Network Formation II. Clustering Models

    Models of Network Formation III. Preferential Attachment


    Tu Oct 18
    Midterm Review Session During this lecture, the TAs will hold a review session in preparation for Thursday's midterm exam.

    Here are solutions to Homework 1. The average score was 88 and the standard deviation 15.6.

    Th Oct 20
    MIDTERM EXAMINATION The midterm will be held in class on Thursday, October 20. It will a closed-book, closed-note exam covering all material in the course to date.

    To help you prepare for the midterm, here are past midterm examinations (some but not all with solutions) from 2015,   2014,   2013,   2012,   2011,   2010,   2009,   2008,   2007, and 2006. Please remember that course content and schedule changes from year to year, so these midterms definitely cover material we have not yet, or will not, discuss this term; and conversely, there are new topics we've introduced this term that are not represented on these past midterms.

    Th Oct 27
    Incentives and Collective Behavior
    [PDF]   [PPT]
    (Rev. 10/25)

    Read Schelling, "Micromotives and Macrobehavior", Chapters 1, 3 and 4.

    Coursera video associated with this lecture:

    Towards Rational Dynamics in Networks

    Tu Nov 1
    Th Nov 3

    Introduction to (Networked) Game Theory
    [PDF]   [PPT]
    (Rev. 10/27)

    Coursera videos associated with this lecture:

    Basics of Game Theory

    Games on Networks: Preview

    Th Nov 3
    Tu Nov 8
    Tu Nov 15
    Networked Games: Coloring, Consensus and Voting
    [PDF]   [PPT]
    (Rev. 11/2)

    Read the following articles associated with these lectures:

    Experiments in Social Computation, MK.

    Behavioral Experiments on a Network Formation Game, MK, S. Judd, Y. Vorobeychik.

    Coursera videos associated with these lectures:

    Games on Networks: Coloring and Consensus

    Games on Networks: Biased Voting

    Here is the midterm solution set.

    Th Nov 10
    QUIZ #1

    This lecture we'll have a quiz that consists of multiple-choice questions covering all course material to date. It will be closed-book and closed-notes.

    Th Nov 17
    Tu Nov 22
    Tu Nov 29
    Th Dec 1
    Trading in Networks
    [PDF]   [PPT]
    (Rev. 11/15)

    Coursera videos associated with these lectures:

    Trading in Networks: I. Model

    Trading in Networks: II. Network Structure and Equilibrium

    Trading in Networks: III. Behavioral Experiments

    Here is Homework 2, which is due in hardcopy format by 10AM on Tuesday, December 13 (at the final exam review session).

    Tu Dec 6
    Th Dec 8
    Internet Economics
    [PDF]   [PPT]
    (Rev. 12/6)
    Coursera videos associated with these lectures:

    Internet Games: I. Packet Routing

    Internet Games: II. Sponsored Search

    Internet Games: III. Other Economic Problems

    THURSDAY DEC 15 FINAL EXAM The final exam for the course will be held Thursday, Deecember 15 from 9 to 11 AM in Stitler Hall room B6. It will be closed-note, closed-book, and inclusive of all material from the entire course.

    There will be a review session for the final on Tuesday, December 13 from 10 to noon in our usual Berger Auditorium location. Homework 2 should be turned in at the start of the review.

    Here are summary statistics from the assignments so far:
    Homework 1 average 88, standard deviation 15.6;
    Midterm average 73.5, standard deviation 13.4;
    Quiz average 81.7, standard deviation 9.6.
    As a very rough guide, if you were exactly at the average on all these assignments, you'd probably be in approximately B/B+ territory so far. Please remember that the midterm and final together will determine more than half your course grade.

    Here are some past final exams, some with solutions, to help you study. Please note that some of the questions are on topics we did not cover this year, and that we covered topics this year that are not represented on the exams.

    [2004]   [2005]   [2006]   [2007]   [2008]   [2009]   [2011]   [2012]   [2013]   [2014]   [2015]