Jeffrey D. Ullman
Jeff Ullman is the Stanford W. Ascherman
Computer Science (Emeritus).
His interests include database theory, database integration, data
education using the information infrastructure.
What's New |
Third Edition of Mining of Massive Datasets
The third edition is now available in hardcopy from
By agreement with Cambridge University Press, it may be downloaded gratis Here.
Gradiance is a system for creating and administering class exercises.
These homeworks and progamming labs are designed to teach students, rather than merely
to test. Through the concept of a "root question," students can repeat the same
work several times, and are given advice when they make an error.
Directions for using the system, either as a student or an instructor can
be found Here.
Free Book: Foundations of Computer Science
In 1992, Al Aho and I published a book called Foundations of
Computer Science, whose goal was to present CS theory as something
integrally connected to CS practice. For example, we viewed recursive
programs, recursive definitions, and inductive proofs as the same thing.
We believe the book deserved a better fate, but the publisher took it
out of print years ago. Having received back the rights to the book, we
are happy to make it freely available Here.
I Would Like to Hear From You, But...
I generally enjoy getting emails, even if it is to tell me of a mistake
in a book.
In fact, those notes are particularly important; they help not only me
and my coauthors, but more importantly, later readers of the book.
I try to respond helpfully and in a timely manner to email that isn't spam.
However, there are two classes of emails that I think should not be
written and that get a form response.
As part of my role as old curmudgeon (replacing my previous role as
young curmudgeon), I have been writing a few articles about things I
think especially stupid. I hope to write more.
Experiments as Research Validation -- Have We Gone too Far?.
For a long time, I've had the feeling that we -- the database community and maybe the CS community at large -- put too much
stock in experiments to justify research, and not enough stock in traditional analysis of algorithms. So I wrote a little
essay on the topic.
Answers to All Questions Iranian.
Am I the only one who gets peppered with questions from Iranians? They're
technical questions or political questions, but there seems to be a system
behind them. So I decided to save time and answer them all here.
Shortly after 9/11/01, I wrote this article on
fundamentalism --- the nonnegotiable belief in some unproven hypothesis.
It's been added to periodically, and rambles a bit, over the foolishness
of the Palestinian leadership, the drug warriors, the politically correct, the
anti-abortion crowd, and a few others.
This article also advocated research on a system like "Total
Information Awareness," although I doubt that it had any
influence on that development.
4-Way Stop Signs.
Dumb traffic policies have always been way up on my list of things I'd
like to fix but can't. The global problem is that those with the power
to decide, focus on specific risks, which they can see.
But in solving one problem, they
often introduce far more harmful effects --- e.g., pollution.
The problem is that the harm is distributed sufficiently widely so that
no one can point to a particular death and attribute it to a particular
instance of some dumb
traffic policy. This polemic, originally written for Club Nexus (the
prototype for Orkut),
focuses on the 4-way stop signs on Stanford Campus, but the principles
Attack of the Fifty Foot NIMBY's.
Throughout my life, I've been infuriated by the tendency of our social
structure to allow theft, as long as the loss is distributed in tiny
parcels among a large number of people. "Affirmative action" is probably
the best known of
these subtle thefts, but this essay is not about affirmative action.
Rather, it's about a theft that occurs on our streets every day, yet no
This article was written for the Knuth Prize. Don, who is of course
ineligible for the Knuth Prize, would probably say we should get rid of
all patents. I don't agree, but I do feel that in the software area,
things have gotten out of hand. Here, I tried to argue that courts
should apply the same standards that are used when choosing papers
worthy of presentation at a conference, to the matter of whether a
certain software idea deserves a patent.
University of California
The UC system, unlike every other
university in this country,
refuses to offer the maximum
confidentiality that the law allows for letters of recommendation that
they solicit. Members of the various
computer-science departments in the UC system
understand that this policy makes letter-writing irrelevant and deprives
them of an important source of advice. However, the policy comes from
so high up that it is impossible for them to do anything about it. I
have therefore endeavored to put in place a solution similar to that
used in response to the equally foolish "Buckley amendment," which gave
student applicants the right to see their recommendations. The document
referred to is a pledge that the person about whom you are writing a
letter can sign, to assure you that you can write an honest and frank
letter without fear of later reprisal or embarrassment. I wish the UC
departments would themselves solicit this pledge, in order to preserve
your anonymity as well as your privacy, but apparently they are
forbidden to do so.
Books --- Past and Future
For some sets of notes and materials for supplementing current books,
Jeffrey D. Ullman
ullman @ cs.stanford.edu