Tales from the ArXiv: Modeling Stupid People

I am intrigued by this paper, which is called Cipolla’ s game: playing under the laws of human stupidity.

Here is a screenshot to whet your appetite.

Finding Identical Packs of Skittles

One blogger has examined the probability of finding identical packs of skittles and posted their data online.

In my new lower-division mathematical modeling course (Math 42; "Introduction to Data-Driven Mathematical Modeling: Life, The Universe, and Everything"), we started our unit on discrete stochastic modeling today, so this post makes me very happy! I have, of course, e-mailed my students about this.

(Tip of the cap to Jeremy Jay.)

Course Nomenclature in our Imminent Data Theory Major

The UCLA mathematics department has a course called "Math 142: Mathematical Modeling", and my new lower-division mathematical-modeling course for our new Data Theory major was thus given the label "Math 42".

Given such an opportunity, I needed an appropriate name for the course. pic.twitter.com/mUGK1th012

— Mason Porter (@masonporter) March 1, 2019

Proof of Existence of Sunlight in England

At least it was a book that was published in The Other Place. ;)

“Mason’s knowledge was as faded as the book from the British sun.”

Proof of existence of sunlight in England. :) pic.twitter.com/d7z7YbgLAy

— Mason Porter (@masonporter) July 20, 2018

Children to be Named Later (Best. Erratum. Ever.)

The excellent new book by Kiss, Miller, and Simon on epidemics and networks also has an erratum that is one of my all-time favorites. (See their website of errata.)

In fact, I think this error is a feature of the book, rather than a bug (especially given that I automatically think of Paul Erdős). By the way, the book itself is awesome, so go take a look at it. Here is a screenshot of the erratum.

(Tip of the cap to my Ph.D. student Yacoub Kureh for pointing this out to me in our meeting today. This erratum is an instant classic.)

The Random Walker then Heads Towards the Hills

Here is a sign that you know you're tired: You are looking at a description of a random-walk model, and it looks like the text says "the walker then heads towards the hills". (It actually says "tills" rather than hills, as we're modeling shopper trajectories.)

But this gave me a wonderful mental picture of an exhausted random walker leaving a network in disgust and heading off towards the hills. My picture also has a sunset in it.

A Video of My Seminar on "A Simple Generative Model of Collective Online Behavior"

On Friday 27 May, I gave a talk at the Oxford Internet Institute on "A Simple Generative Model of Collective Online Behavior". The video was posted online today. My talk, which took place at the Oxford Internet Institute, was part of an event for the Computational Social Science Initiative London.

I spoke about this paper, which I like to call our "Small Data" paper.

You may also be interested in videos of some of my other presentations.

Limit-Cycle-Oscillator Models of Bipolar Disorder: Revisited

Years ago, Steve Wirkus and I coauthored (with several undergraduate students) a paper that first introduced the idea of using limit-cycle oscillators to model bipolar patients. Our model was a toy model, but years later several of my colleagues at Oxford have been doing amazing things from a more data-centric perspective. Their latest paper is especially exciting for me. It does what we dreamed about and speculated about 12 years ago in our paper: taking the basic idea of a limit-cycle oscillator and combining it with clinical data in a realistic way. (The authors of this work understandably also incorporate noise into their model.)

Quoting the last few lines of our conclusions: "In this respect, we view our work as a first step in developing mathematical models of the mood swings of bipolar individuals. Our intent is to provide a mathematical framework that ultimately leads to the development of more detailed models of bipolar disorder that incorporate clinical data. With this work, we hope to motivate the collection of time-series data from clinical trials that will lead to refinements of our model that incorporate such data. In our view, dynamical systems theory and mathematical modeling in general can lead to important advancements in the understanding of bipolar disorder."

(Tip of the cap to Society for Industrial and Applied Mathematics, who shared a popular account of the work on Facebook.)

Mathematical Modeling Problem: Just How Many Suckers Are There Right Now?

The phrase "There's a sucker born every minute." was allegedly uttered by a famous person during the 19th century. Assuming it was true and estimating the year based on the possible people to whom the phrase has been attributed, and birth and death rates at appropriate times, estimate how many suckers occupied Earth on 1 January 2015. Be sure to state all of your assumptions explicitly and clearly.

Note: Considerations could include, e.g., whether the rate of births resulting in suckers has changed over time, whether somebody who was born a sucker must necessarily remain so, etc.

Extra credit: Derive from physical principles how many licks it takes to get to the Tootsie Roll center of a Tootsie Pop.

If you look at the Wikipedia entry, you'll see that the quote is of unknown origin and that the attribution to P. T. Barnum is apparently almost certainly wrong.