Economics of Information Networks

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This is the home page for Economics of Information Networks in the Master Program of Service Engineering.

Please, please, please send me email if there are any problems with any materials or links posted here.

Previous Updates

Thu Dec 16 13:20:41 2021

• I'm still working on Lecture 5. Gradually catching up to myself this term. :-(

• The raw video (lecturer only, no slides) for Lecture 4, Part 2 and Lecture 4, Part 3 are now available. These videos will be replaced with "lecturer on slide" versions when processing is complete.

Thu Dec 16 09:35:17 2021

• The slides for the full Lecture 4 are now available.

• In Part 2 (slides 18-34), we go into more detail about some basic features of graphs, and useful measurements.

• Part 3 (slides 35-45) follows up on Lecture 3's discussion of information cascades with a more general discussion of cascading behavior in networks.

Thu Dec 9 12:41:27 2021

• Video for Parts 2 and 3 of Lecture 4 are delayed. The slides for Part 3 are also delayed. Slides for Part 3 will be posted later today. I am not sure when the videos will be done.

• The slides for Lecture 4, Parts 1 and 2 are now available.

• Lecture 4, Part 1 is now available as video (45m57s), corresponding to slides 1-17. We look at power laws, a kind of statistical distribution that seems to characterize many economic collections: sales of books, videos, and music recordings, number of followers in social networks, and other measures of "popularity".

Thu Dec 2 02:22:49 2021

Note: In the lecture videos and the slides, all parts are dated 2020, and parts 3 and 4 are labeled "Lecture 3". That's because I'm recycling the videos from last year. But if you search on Microsoft Stream, they are labeled Lecture 2, Parts 1-4.

As last week, I will be available in the Teams team for the course during the scheduled hours, 12:15 to 15:00. I should be monitoring most of the time, but it you don't get a response in a few seconds, leave a message in the meeting chat and I'll get back to you fairly soon.

• This week the slides for Lecture 3 are in one file, but the page numbers for each lecture are listed.

• Lecture 3, Part 1 is now available as video (49m34s), corresponding to slides 1-26. We look at Granovetter's arguments about "the strength of weak ties," and at some quantitative analysis of social network data.

• Lecture 3, Part 2 is now available as video (27m10s), corresponding to slides 27-39. We discuss more quantitative measures in networks, such as betweenness and embeddedness, and relates them to ideas in social behavior such as power and trust. Finally we describe the Girvan-Newman graph partitioning algorithm which accurately predicts the split of a club into two.

• Lecture 3, Part 3 is now available as video (42m07s), corresponding to slides 40-66. We discuss the structure of the World Wide Web at several levels of detail, and its relation to the Internet. Then it turns to the problem of automatically determining "importance" of web resources.

• Lecture 3, Part 4 is now available as video (33m18s), corresponding to slides 67-82. We discuss information cascades: dynamic processes where information spreads through a network. These processes are related to "flame wars" and "disinformation campaigns" on social networks, as well as to some kinds of behavior in markets.

• I will update the list of homeworks available with due dates, and the table on this page, later. Note: I will probably improve the instructions for some of the homeworks in that document.

Thu Nov 18 03:14:00 2021

Note: In the lecture videos and the slides, all parts are dated 2020, and parts 3 and 4 are labeled "Lecture 3". That's because I'm recycling the videos from last year. But if you search on Microsoft Stream, they are labeled Lecture 2, Parts 1-4.

As last week, I will be available in the Teams team for the course during the scheduled hours, 12:15 to 15:00. I should be monitoring most of the time, but it you don't get a response in a few seconds, leave a message in the meeting chat and I'll get back to you fairly soon.

• Lecture 2, Part 1 is now available as slides and video (34m27s). It treats network externalities which are asymmetric, and the dynamic evolution of markets with changing technology.

• Lecture 2, Part 2 is now available as slides and video (40m26s). It treats network flows, optimization, and the Braess Paradox (a dynamic version of the Prisoner's Dilemma in which the Nash equilibrium induces socially optimal allocation of traffic to two possible routes, but adding capacity to the network results in the worst possible outcome in which all traffic uses one route.

• Lecture 2, Part 3 is now available as slides and video (21m07s). It describes a number of networks that are really used in daily life and in academic research. Where relevant, it explains some of the economics associated with each network.

• Lecture 2, Part 4 is now available as slides and video (27m41s). It describes a number of basic network structures, and some quantitative measure that attach to them.

• I have made a complete list of homeworks available with due dates. The later lectures of assignments and due dates are probably late! They will move forward in time. Others may be added or substituted.

Thu Nov 10 15:26:11 2021

• Part 1 of the lecture notes and audio recording (52m25s) for the Introduction to these lectures are available.

• Part 2 of the lecture notes and audio recording (53m57s) on market graphs, network externalities, Metcalfe's Law, and logistic growth with network externalites are available.

• For reasons I don't understand, graphics are displayed in the wrong place. I'll try to fix them this weekend.

Thu Dec 24 12:05:38 2020

• Due to the coronavirus, the final exam is in take-home format plus a short interview. Send me email or contact me on Teams in the Economics of Information Networks channel if you want to consult about grading or the assignments.

  1. Hand in the homework. A full list of homework is now available, separate from the lectures. Send me email, or contact me on Teams, if you do not understand a problem.

  2. By December 29, choose a research topic related to the economics of information networks. Think of this as if you were going to use it to apply to the graduate program with this topic. I suggest you propose several topics and indicate your preferences. Send me email to submit. You may write in the body of the email, or submit a Word document or PDF as an attachment.

  3. Make an appointment to discuss your topic by Teams or Zoom. This will take about 10 minutes.

  4. Based on the discussion write a research proposal for your topic of about 1-2 A4 pages, and submit it by January 15. Your proposal should explain

     • why it interests you,

     • what scientific, policy, or business benefits flow from solving the research problem

     • at least one specific research question or hypothesis

     • necessary data and means of collection

     • method of analysis

     • expected or hoped-for results.

  Remember, this is of the scale of the proposal you submitted to apply for the graduate program.

Fri Dec 18 10:57:58 2020

• Lecture 5 Part 2 is now available as slides and video.

Thu Dec 17 15:56:27 2020

• Lecture 5 Part 1 is now available as slides and video.

Thu Dec 10 19:01:58 2020

• Lecture 4, Part 2 is now available as slides and video.

Thu Dec 10 14:42:48 2020

• Lecture 4, Part 1 is now available as slides and video.

Thu Dec 10 13:06:02 2020

• An improved version of the slides has been uploaded (with slide 13 completed).

Thu Dec 10 12:06:03 2020

• Lecture 4, Part 1 is now available as slides. Video software is still processing, and will be uploaded when done.

Fri Dec 4 10:37:07 2020

-Lecture 3, Part 3 is now available as slides and video.

Thu Dec 3 23:05:07 2020

-Lecture 3, Part 2 is now available as slides and video.

Thu Dec 3 10:59:02 2020

• Lecture 3, Part 1 is now available as slides and video.

Wed Dec 2 23:49:33 2020

• Lecture 3, Part 1 is now available as slides. Video is coming soon.

Wed Dec 2 21:12:20 2020

• It looks like I failed to upload Lecture 2, Part 2. Here's the video and slides.

Thu Nov 19 15:34:41 2020

• Lecture 2, Part 1 is now available as video (including the slides) and slides (same as earlier).

Thu Nov 19 12:48:03 2020

• Part 1 of the lecture notes and video recordings of the lecturer part 1a and part 1b have been uploaded while software processes combined slides and video.

Thu Nov 12 15:26:11 2020

• Part 2 of the lecture notes and audio recording (53m57s) on market graphs, network externalities, Metcalfe's Law, and logistic growth with network externalites has beem posted.

• The previous news was updated with the duration of the audio recording.

Thu Nov 12 12:51:52 2020

• The lecture notes and audio recording (52m25s) for the introduction part of this lecture have been posted. A second part will be posted shortly. Two videos containing the same material are still being processed by editing software, and will be posted tonight.

Thu Nov 14 02:17:41 2019

• Previous Updates are currently entirely from last year, and perhaps before. Eventually I will delete all updates from previous years.

Thu Nov 15 16:06:15 2018

• Lecture 2 corrections uploaded.

• Lecture 3 draft uploaded. Very incomplete.

• Homeworks have been uploaded due to a change in format template. No content, including instructions and deadlines, was changed.

Thu Nov 15 11:44:59 2018

• Homework 6 and Homework 7 have been posted.

• Homeworks have been updated with correct due dates and submission instructions. If you have already submitted to turnbull@sk.tsukuba.ac.jp with the correct Subject:, there is no need to resubmit.

  Homework 1 Homework 2 Homework 3 Homework 4 (all due 11/15) Homework 5 (due 11/22).

Thu Nov 15 03:39:36 2018

• Notes for Lecture 2 have been uploaded. This is a draft, there will probably be changes before lecture.

Wed Nov 7 18:35:38 2018

• Lectures are work-in-progress, and usually are updated both just before and just after class.

• Homework has not yet been reviewed for accuracy for this year. In particular you should not trust due dates in the homework assignments. The table in Links to Homework Assignments is tentative, but correct at this point in time.

Thu Nov 15 16:06:15 2018

• Lecture 2 corrections uploaded.

• Lecture 3 draft uploaded. Very incomplete.

• Homeworks have been uploaded due to a change in format template. No content, including instructions and deadlines, was changed.

Thu Nov 15 11:44:59 2018

• Homework 6 and Homework 7 have been posted.

• Homeworks have been updated with correct due dates and submission instructions. If you have already submitted to turnbull@sk.tsukuba.ac.jp with the correct Subject:, there is no need to resubmit.

  Homework 1 Homework 2 Homework 3 Homework 4 (all due 11/15) Homework 5 (due 11/22).

Thu Nov 15 03:39:36 2018

• Notes for Lecture 2 have been uploaded. This is a draft, there will probably be changes before lecture.

Wed Nov 7 18:35:38 2018

• Lectures are work-in-progress, and usually are updated both just before and just after class.

• Homework has not yet been reviewed for accuracy for this year. In particular you should not trust due dates in the homework assignments. The table in Links to Homework Assignments is tentative, but correct at this point in time.

Tue Dec 20 12:25:40 2017

• The testbank has been updated. No more questions will be posted.

  The set of problems in this testbank is at least twice as long as the test will be. It probably is no more than three times as long (some of the problems are "large" so if they were included as is the test would probably be 7 or 8 problems).

• You should also look at the exercises for Ch. 2 (Sec. 2.5) and Ch. 3 (Sec. 3.7) of Kleinberg and Easley.

Tue Dec 19 23:25:40 2017

• The testbank has been posted. Watch for more questions to be added around 12:00 tomorrow. No more after that.

Mon Dec 18 23:43:54 2017

• The testbank has been posted. Watch for more questions to be added.

Thu Dec 14 11:40:01 2017

• Partial Lecture 5 notes have been posted.

• Minor updates to Lecture 4 notes have been posted.

Mon Dec 11 18:08:12 2017

• Lecture 3 notes have been updated, but are still incomplete. More notes, homework coming soon.

Mon Dec 11 00:34:37 2017

• Lecture 4 notes have been posted.

• Lecture 3 notes will be posted soon.

Thu Nov 16 16:19:30 2017

• Homeworks will be posted soon, but will be due November 30. Note that there is no class that day due to undergraduate entrance examinations.

• Lecture 1 notes were updated to reflect the material actually covered, and to use figures of reasonable size.

• Lecture 2 notes were updated to reflect the material actually covered, and to use figures of reasonable size.

• Homework 5 was not actually assigned yet, and you should ignore it for now.

Thu Nov 9 15:48:17 2017

• Lecture 1 notes were updated.

• Homework 1, Homework 2, Homework 3, and Homework 4 were uploaded. These are all due November 16, 11:00am.

  Instructions for Homework Submission and some Homework Hints were also made available.

Wed Nov 8 21:42:12 2017

• This page has been partly updated for Autumn 2017, Module B

Thu Dec 15 15:39:57 2016

• Final exam with sample answers has been posted.

Tue Dec 6 15:30:11 2016

• Homework 5 has been posted.

• The first four homeworks had dates "2015" not "2016". This has been corrected. (The month and day were correct.) Your browser may show that they have been updated, but you do not need to download them again.

Thu Nov 24 01:34:45 2016

• Lecture 1, Lecture 2, Homework 1, Homework 2, Homework 3, and Homework 4 have been posted, as well as the Homework Submission policy and some Homework Hints.

• Note: The urls to lecture files have changed from ``ohp#.pdf`` to ``lec#.pdf``. This doesn't affect you much if you always use the link, but if you've saved the file you need to remember which one you've got. (I did this for convenience of sorting the files in my workspace.)

Thu Nov 12 16:01:55 2015

• Notes for Lecture 1 updated: Introduction to networks, graphs, and information networks. Only typos were corrected. To do later: fix the image for "matching markets", add due dates to homeworks.

• Lectures 2 and 3 are stubs (basically empty).

Thu Nov 12 12:15:52 2015

• Notes for Lecture 1 updated: Introduction to networks, graphs, and information networks.

Wed Nov 11 22:57:32 2015

• Notes for Lecture 1: Introduction to networks, graphs, and information networks are available.

• Future schedules for lecture and homeworks are not up to date yet. The first homeword assignment(s) will be announced in class.

• Old news was moved to Previous Updates.

Fri Oct 31 08:07:45 2014

• Uploaded partial notes for Lecture 3.

• More complete notes for Lecture 2 are available.

Fri Oct 10 08:00:28 2014

• Uploaded partial notes for Lecture 2.

• Full notes for Lecture 1 are available.

Fri Oct 3 03:19:35 2014

• Uploaded partial notes for Lecture 1.

Thu Oct 2 21:37:38 2014

• This is a new course, offered for the first time in Fall 2014. There are no past materials (such as final examinations or homework assignments available for this course. However, the format of the course will be overall similar to Basic Data Analysis (for the now-abandoned MBA program).