Archive for Brown

Thesis turned in!

sortingIt’s been a hectic few weeks, but it felt great to finally hand in my thesis this afternoon. I have dropped on a page the abstract of my paper and a graphical walk-through of my findings. The paper itself is available here. I’m especially grateful to my thesis advisor, Oded Galor, for so many conversations and comments. I’m also very appreciative of many friends for helpful discussions along the way about my findings (and particularly to Chris and Christine for comments this week!).

I’ll be presenting my thesis to the Economics department May 1 (anyone is welcome to attend). I’ll also be making a less technical presentation at Theories in Action on Sunday, April 28.

Submarine Patents from a 21st Century Vantage Point: Honors Thesis Proposal

I am writing an interdisciplinary senior thesis at Brown spanning the fields of computer science and economics. The subject is submarine patents.

A submarine patent is a patent whose prosecution review at the US Patent & Trademark Office is purposefully prolonged by the applicant, in the hopes of “emerging” some years later with a patent on what has become a fundamental technology, extracting licensing fees from businesses who have already built upon this technology without knowledge of the patent’s filing.

Two reforms made submarine patents much less worthwhile to pursue. While patent terms used to be determined from issue date, starting in June of 1995, all new patent filings would receive terms from date of filing — the fact that the clock was ticking during prosecution made stalling at this stage much less desirable. A further reform came in November of 2000, when the USPTO announced that most patent applications would be published to the world 18 months after filing. Given the changes in patent term structure and the lifting of the veil of secrecy surrounding patent applications, the ability for inventors to unexpectedly corner a market long after filing their invention has been effectively eliminated.

Despite the closure of these loopholes, submarine patents continue to issue. In examining all patents that have issued over the past several decades, a single anomaly is prominent: many applications self-sorted to file prior to the closing of the loophole. A tremendous number of patent applications were filed in these days and weeks, and we now see that these were no ordinary applications. In fact, applications filed in these few weeks represent the most pronounced spike in average pendency in modern history. Identifying submarine patents as those filing prior to this discontinuity offers a unique vantage point from which to study the motives for and outcomes of submarine patents.

First, I have downloaded the full text of every patent granted in the past three decades.

I transformed these documents into roughly the following relations (number of tuples in parentheses):

  • Basic bibliographic info — one line for each patent grant (4.8M) (dta sample)
  • Assignee: name, address, etc. (for all assignees of patent) (4.3M) (dta sample)
  • Inventor: name, address, etc. (for all assignees of patent) (11M) (dta sample)
  • References to other patents (in the US and abroad) (55M) (dta sample)
  • References to “non-patent literature” (papers, brochures, etc.) (16M) (dta sample)
  • Parents (1.8M) (dta sample)
  • Fields searched by examiner as prior arts (11M) (dta sample)

Presentation to Brown’s Economics Honors Thesis Class Nov. 20, 2012 (PDF):

Global Interplays of Values, Wealth, and Geography

I wrote a research paper for my course in Geographic Information Systems (GIS). I had a blast writing it, and there was plenty of Stata and ArcGIS play to be done. I’m posting a download link here, in case anyone is as excited about this kind of stuff as I am.


  • It’s true that distance to the equator is a good predictor of wealth. It predicts 28% of the variance in per-capita GDP! This was a satisfying result — highly significant.
  • We can do similar studies with measures of cultural values. It seems that many values also change similarly with geography.
  • Using four fairly arbitrarily selected values as regressors, about two thirds of the variance in per-capita income can be predicted. This was really surprising to me, and it seems like there’s a lot of similar work to be done here regarding mapping and cultural values.

Weaker Consistency Models

Here are slides I created for my databases class. The theme is weaker consistency models, and they cover the following papers:

  1. Werner Vogels, Eventually Consistent, Communications of the ACM, 2009
  2. J. Baker, et al., Megastore: Providing Scalable, Highly Available Storage For Interactive Services, CIDR, 2011
  3. Pat Helland, Life Beyond Distributed Transactions: An Apostate’s Opinion, CIDR, 2007

Slides in:

I’ve reached Google Images Fame

A search for "Christina Paxson"A friend just pointed this out to me. It’s quite touching, actually. If only I can find a way to jump ahead of that female inmate, I’ll be all set.

Parking tickets in Providence, rents for farmers

I got a ticket over a month ago for parking in an unmarked bus stop.

I sent in a letter to the court showing irrefutable photographic evidence that there were no signs marking a bus stop visible from where I was parked. In response, I got a court summons. It’s for 8 a.m. on the Friday of Spring Weekend. The letter also came with an extra envelope, just in case I’ve changed my mind about refuting my ticket. Oh, and for my convenience, I can also pay online or over the phone. Something tells me the city is very interested in seeing more money from my hands go into its groping fists.

I remember a question on one of my exams for David Weil’s Economic Growth class. The question was along the lines of: A farmer works his land, and he has to pay an exorbitant rent to the landowner. He could work his land more productively it weren’t for this rent-seeker. Is the rent inefficient? That is, does it reduce the total size of the pie for society?

I and several others said yes; now the farmer can’t produce as much crop. But the rational answer is that it depends on what his rent money is going toward. If it goes toward buying the landlord booze, then the rent is inefficient. If it goes toward investing in worthy endeavors, there is nothing inefficient about that use of money. Perhaps the size of the pie would even grow.

Let’s be honest. Providence needs to close a budget shortfall, and this parking ticket is more of a desperate tax than a parking ticket. A part of me wants to say it’s okay just to go ahead and pay the ticket — sure it’s $30 out of my pocket, but it’s not like I’m wasting it by throwing it into the toilet.

On the other hand, a growing part of me remembers that test question, and I am beginning to wonder whether this really is the inefficient sort of rent — the type of rent that would do more good for society in my hands than in the irresponsible ones of the city. Just something to think about.

I’d also be curious to know how many people take off from work or school to attend 8 a.m. court over a $30 parking ticket. That just sounds like extortion to me.

PawPrints from a Macbook

Update: You can now also use PawPrints from any computer by following these instructions from Brown. They’re probably much easier. Also, the print driver is already installed on the latest Mac operating systems anyway.

Audience: The intended audience of this post is Brown students who have CS department logins and use Macs, and from time to time need to print at the libraries. I suspect this strategy can be adapted for Windows users or for similar systems at other schools. Let me know if you have anything to share.

If you have a CS department account and SSH set up on your laptop, you don’t need to bother searching for a free computer in the SciLi next time you need to print. If you run Mac OS, copy the script below into an empty text file (or you can download it here.) You should name the file “pawprint” (with no extension) and change my CS department username (ambell) to your own.

The file should be put in /usr/local/bin. If your account doesn’t have have admin capabilities for your laptop, you may need to use a command like “sudo mv pawprint /usr/local/bin.” Then navigate to that directory, and add executable permissions to the file: type into the terminal “sudo chmod +x pawprint.”

To print a file from your Mac to PawPrints, just navigate to the directory where your files are and type pawprint filenames. You can type as many file names as you want at a time from your laptop, then walk over to a print station. If you entered multiple filenames, I believe PawPrints will bundle them all into one print item, named after the first file.

Thanks to Chris Sulawko for suggesting a few days ago that I try printing to PawPrints over ssh!


echo “starting print of:” $@
scp $@
ssh lpr -P pawprints $@
ssh rm -f $@
echo “files have been sent to pawprints”


  1. Tell the user the parameters passed to the function
  2. Copy the files to your home directory on your departmental account.
  3. Order the print of the files.
  4. Remove the files.
  5. Tell the user that the files have been sent.

Brown’s new president reflects growing academic interests of students (with graphs)

Brown’s Chancellor Tom Tisch announced yesterday to an impromptu horde of students and staff in Sayles Hall that Princeton economist Christina Paxson would replace Brown’s President Ruth Simmons at the end of the year. A professor of Economics and Public Affairs, Paxson is also dean of Princeton’s Woodrow Wilson School of Public and International Affairs. She chaired Princeton’s Economics department from 2008-2009.

Paxson might not be on the types of high-profile boards outgoing president Simmons sat on (Goldman Sachs, Pfizer, and Texas Instruments), but she has been elected to serve a year-long term as vice president of the American Economic Association and is a director of the non-profit social research group MDRC.

She is in the top 5% of the world’s economists ranked by citations (#401) according to RePEc‘s rating system. Her areas of interest according to her Princeton bio are health policy, child well-being, and economic development. (When I have more time, I hope to look over some of her papers, listed at the RePec link above.)

Ties like hers to economic research organizations are new for Brown’s presidency, but with a quarter of Brown undergraduates concentrating in Economics or International Relations, it seems that Paxson is a fitting choice. Not long after the announcement came out, I heard at least two comments from students seeking to get recommendations to the Woodrow Wilson School from Paxson. As best I can tell, she is the first Brown president to call herself an economist, judging by Brown’s biographies of past presidents and other online sources.

Plus, from what she said in her acceptance speech in Sayles yesterday, she seems already familiar with the Brown way:

“My big brother, this clean-cut, studious kid, went off to Brown and came back at Thanksgiving vacation to Pittsburgh,” she said. “He had long hair, he was listening to new music and he argued with my mother about the ethics of eating meat.”

Below are a few quick-n-dirty graphs of Brown Econ(-related) and IR concentrations completed by year; data is from Brown’s Institutional Research Office.


Providence: Don’t bite the hand that wants to feed you

I remember reading a provocatively headlined article over winter break stating that Brown had “reneged” on a deal with Providence to shell out some extra cash ontop of the payments in lieu of taxes it already makes. GoLocalProv obtained a copy of the letter from Providence’s mayor to Brown’s president. I found the tone of the letter striking; here is their description:

“Unfortunately, our agreement never reached the Brown Corporation for their consideration,” Taveras writes in the letter. “Instead, the Corporation approved two of your agenda items – ROTC and athletics—as well as received $34.2 million in gifts to the University. The Corporation also received news that Brown’s endowment grew to a market value of $2.5 billion. The future of Brown and Providence was never discussed or voted upon.”

Taveras said that a Dec. 15 letter from Simmons was “substantially different from our December 12 conversation and a far cry from our original agreement which provided for close to $4 million annually and valued at $39.5 million over 10 years with a view towards an additional 10 year extension.”

Near the end of the letter, Taveras said that the city must obtain $7.1 million from the tax-exempt universities and hospitals and the money expected to come from Brown is an integral part of its budget. He also made it clear that the city will take legal action to pursue the funds that were agreed to if the Corporation does not sign off.

“If that is the case, the City will pursue that revenue from Brown using alternate legal pathways,” the letter states.

Earlier this month, Taveras began not-so-subtly intimating that Providence could be the next to follow nearby Central Falls into the b-word (bankruptcy — quite the buzzword in RI nowadays).

A few weeks ago, when Providence’s Johnson and Wales University tripled their concessions to the city, the mayor spoke as if JWU was the only one who cared about the city. Try to picture him scowling up the hill at Brown while he says this.

“I am pleased to announce this new agreement with Johnson & Wales, and am grateful to the university for being a strong partner to the City of Providence,” said Mayor Taveras. “Johnson & Wales and all of our city’s major tax-exempt institutions provide great economic and cultural value to Providence. At the same time, our tax-exempts cannot thrive if our city is in continual fiscal crisis. This agreement helps to address an unsustainable structural imbalance in our city’s finances caused by the great and growing percentage of tax-exempt land in Providence.”

As a Brown student and as someone who has spent a year covering the top-brass beat for Brown’s newspaper, I can assure any reader that President Simmons and the rest of the Brown administration do care about Providence, and they do realize Brown will feel ramifications of a crippled Providence. And Brown doesn’t necessarily mind contributing money and resources to Providence, which Brown already does voluntarily.

What the people up on College Hill don’t see eye to eye on with the people down across the river is how to avoid that. Taveras needs to understand that when you court potential investors, you can’t just size them up for what they’re worth then shake them down. A more amenable approach to any investor, especially the people who run this university, would be presenting them with some sort of business plan for the city: a way for Brown to contribute more, but to see increasing returns.

To my knowledge, Taveras hasn’t coughed that up. But if he did, I’m sure his talks with Brown would go very differently. It isn’t that Brown doesn’t want to shell out a few million dollars to help save the city. It’s that they don’t want to see a few million dollars go down the toilet in the hands of a city with a record of inflating pensions and mismanaging its finances.

I miss the days when David Cicilline would talk about the city’s need to work with Brown to develop his idea of the “Knowledge District,” a run-down manufacturing sector that planners aimed to revitalize by relocating I-195 away from it to make space for high-tech ventures, like Brown’s new medical school.

That was a partnership Brown could get behind. Taveras’ vague demand for sacrifices from every imaginable constituency — nonprofits, unions, Joe the Plummer’s — is not an endorsable venture. Nonprofits shouldn’t be bullied into that type of financial black hole without assurance that Providence’s situation will in fact better and that the city won’t become dependent on the temporary relief for its operating expenses.