Tuesday, August 14, 2018

What Happens at WorldCon 76 Stays at WorldCon 76

I am at the airport — experiencing a lovely 2.5-hour delay in my flight — and will be flying to San Jose, California to attend this year's WorldCon. Several of my friends will be there, so it should be lots of fun.

I am looking forward to geeking out!

(I am also looking forward to getting out of this crowded, shitty airport. LAX is awful.)

Monday, August 13, 2018

A Wassermanian–Faustian Bargain

Friday, August 10, 2018

"Network Analysis of Particles and Grains"

Our review article on granular and particulate networks, which appeared in advanced access a few months ago, is now out in final form (with its page numbers and other coordinates). Here are some details.

Title: Network Analysis of Particles and Grains

Authors: Lia Papadopoulos, Mason A. Porter, Karen E. Daniels, and Danielle S. Bassett

Abstract: The arrangements of particles and forces in granular materials have a complex organization on multiple spatial scales that range from local structures to mesoscale and system-wide ones. This multiscale organization can affect how a material responds or reconfigures when exposed to external perturbations or loading. The theoretical study of particle-level, force-chain, domain and bulk properties requires the development and application of appropriate physical, mathematical, statistical and computational frameworks. Traditionally, granular materials have been investigated using particulate or continuum models, each of which tends to be implicitly agnostic to multiscale organization. Recently, tools from network science have emerged as powerful approaches for probing and characterizing heterogeneous architectures across different scales in complex systems, and a diverse set of methods have yielded fascinating insights into granular materials. In this article, we review work on network-based approaches to studying granular matter and explore the potential of such frameworks to provide a useful description of these systems and to enhance understanding of their underlying physics. We also outline a few open questions and highlight particularly promising future directions in the analysis and design of granular matter and other kinds of material networks.

Thursday, August 09, 2018

A Touching Song about a Matrix Entry that is not Well-Defined

This is a touching song about a matrix entry that is very sad because it is not well-defined.

Monday, August 06, 2018

Workshop on Evidence-Based Diversity Initiatives

I hope that some of my mathematics, networks, and complex-systems peeps attend this workshop! It looks good.

(P.S. Jess Wade has been doing amazing things in her prolific writing of Wikipedia entries.)

Saturday, August 04, 2018

What Happens in San José (Costa Rica) Stays in San José (Costa Rica)

I am heading off to Costa Rica for a visit related to an epidemiology project related to combatting Dengue Fever, Zika, and Chikungunya using mathematical modeling and network analysis.

Thursday, August 02, 2018

An Author Named "Tapas Bar"

The first author of this new paper is named "Tapas Bar".

Suddenly, I feel hungry.

Our Physics Today Obituary of Norman Zabusky

David Campbell, Alan Newell, and I wrote an obituary of Norman Zabusky for Physics Today. It just came out.

Previously, we wrote an obituary of Zabusky for DSWeb.

Wednesday, August 01, 2018

2018 Fields Medals

The 2018 Fields Medals in mathematics have been announced!

You can also read short prize citations for the four Fields Medalists and the Nevanlinna Prize (in theoretical computer science).

Tuesday, July 31, 2018

"Topological Data Analysis of Continuum Percolation with Disks"

One of my papers came out in final form today. Here are some details and a story.

Title: Topological Data Analysis of Continuum Percolation with Disks

Authors: Leo Speidel, Heather A. Harrington, S. Jonathan Chapman, and Mason A. Porter

Abstract: We study continuum percolation with disks, a variant of continuum percolation in two-dimensional Euclidean space, by applying tools from topological data analysis. We interpret each realization of continuum percolation with disks as a topological subspace of [0,1]^2 and investigate its topological features across many realizations. Specifically, we apply persistent homology to investigate topological changes as we vary the number and radius of disks, and we observe evidence that the longest persisting invariant is born at or near the percolation transition.

And to give a story, or at least the hint of the interesting relationship that I sometimes have with typesetters and editors, here is a note that I received from them while we were working on the galley proofs.

Update (8/05/18): A nice way of phrasing things is that we're in a nonassociative situation, and hyphens are a great tool to indicate exactly (and tersely) where the parentheses should be to group terms in a way that renders their meaning unambiguous. (And, naturally, if somebody makes a change in my text that I don't like, my immediate desire is to change it back.)

Monday, July 30, 2018

A Cartoon Depiction of Deep Learning Versus Traditional Machine Learning

So true. :)

(Tip of the cap to Michael Stumpf.)

The Paradox of PLOS One and Scientific Reports

Whenever I see somebody bragging about getting a paper published by a trashy journal like PLOS One or Scientific Reports, I inevitably wonder whether they're being serious (but naive) or whether they're trolling people. Seriously, I can't tell.

Also, remember the mantra: FIPO (= "Fuck it. PLOS One.")

Sunday, July 29, 2018

Tales from the ArXiv: "Blueberry Earth"

I am amused. :)

(However, I do wish that the author had used the subjunctive in the 'what if' question.)

Update: Here is the first paragraph of the Summary: So, to sum up, to a person standing on the surface of the Earth when it turns into blueberries, the first effect would be a drastic reduction of gravity. Standing on the blueberries might be possible in theory, except that almost immediately they begin to compress rapidly and air starts erupting everywhere. The effect is basically the worst earthquake ever, and it keeps on going until everything has fallen 715 km. While this is going on everything heats up drastically until the entire environment is boiling jam and steam. The end result is a world that has a steam atmosphere covering an ocean of jam on top of warm blueberry granita.

Saturday, July 28, 2018

Complex Variables and the Meaning of 𝛏

This tweet speaks the truth!

Two remarks:

(1) One of the main purposes of taking complex analysis is learning how to properly write Greek letters.

(2) I specifically practiced how to draw \xi when I took complex analysis.

(Tip of the cap to Dave Richeson.)

Smurfy Peer Review

Resolved: I am going to start taking inspiration from The Smurfs when I write referee reports for articles that particularly annoy me.

To wit:

"Where did the authors smurf up this idea?"

"This figure is smurfed."

"The authors might want to consider smurfing the abstract a little bit more."

Update: I know; I know: this isn't very smurfy of me.

Update 2: "A total smurf job."

Tuesday, July 24, 2018

Tales from the ArXiv: Low and High Mason Numbers

Here is a new paper on the ArXiv.

Here is a quote from the abstract: In the limit of low Mason number, the dynamical system admits a periodic solution in which the magnetic moment of the swimmer tends to align with the magnetic field. In the limit of large Mason number, the magnetic moment tends to align with the average magnetic field, which is parallel to the axis of rotation.

I operate in the limit of low Mason number, and I claim that this limit is singular.

Monday, July 23, 2018

Opinion: "Are Theoretical Results 'Results'?"

I agree strongly with Ray Goldstein: YES!!!!!!

Moreover: Hell yes!

This is a major issue for interdisciplinary students and postdocs (and more senior scholars), and this is a very helpful paper for them to read as they navigate these waters. I also really like the fact that Ray included two different versions of a 'Results' section in his opinion article.

"Quasiperiodic Granular Chains and Hofstadter Butterflies"

Our article just came out in final form today. It provides the cover picture of an issue of Philosophical Transactions of the Royal Society A. Here are some details.

Title: Quasiperiodic Granular Chains and Hofstadter Butterflies

Authors: Alejandro J. Martínez, Mason A. Porter, and Panayotis G. Kevrekidis

Abstract: We study quasiperiodicity-induced localization of waves in strongly precompressed granular chains. We propose three different set-ups, inspired by the Aubry–André (AA) model, of quasiperiodic chains; and we use these models to compare the effects of on-site and off-site quasiperiodicity in nonlinear lattices. When there is purely on-site quasiperiodicity, which we implement in two different ways, we show for a chain of spherical particles that there is a localization transition (as in the original AA model). However, we observe no localization transition in a chain of cylindrical particles in which we incorporate quasiperiodicity in the distribution of contact angles between adjacent cylinders by making the angle periodicity incommensurate with that of the chain. For each of our three models, we compute the Hofstadter spectrum and the associated Minkowski–Bouligand fractal dimension, and we demonstrate that the fractal dimension decreases as one approaches the localization transition (when it exists). We also show, using the chain of cylinders as an example, how to recover the Hofstadter spectrum from the system dynamics. Finally, in a suite of numerical computations, we demonstrate localization and also that there exist regimes of ballistic, superdiffusive, diffusive and subdiffusive transport. Our models provide a flexible set of systems to study quasiperiodicity-induced analogues of Anderson phenomena in granular chains that one can tune controllably from weakly to strongly nonlinear regimes.

This article is part of the theme issue ‘Nonlinear energy transfer in dynamical and acoustical systems’.

Sunday, July 22, 2018

I Would Code Anything for Love (but I Won't Code That)

Somebody clearly wants an Ig Nobel... Wow.

(Also, I am highly amused!)

Money quote from the programming language's GitHub page:

"Rockstar is a dynamically typed Turing-complete programming language.

Rockstar is designed for creating computer programs that are also song lyrics, and is heavily influenced by the lyrical conventions of 1980s hard rock and power ballads."

Update (7/23/18): I wrote a blurb about Rockstar for the Improbable Research blog.

Saturday, July 21, 2018

Scientific Nomenclature: The "Thagomizer"

This is so awesome!

(Tip of the cap to C E Watkins.)

"Smooths" Versus "Smoothes"

A new champion was crowned recently.

Update: Also, this may be Microsoft's fault.

Friday, July 20, 2018

Proof of Existence of Sunlight in England

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

Thursday, July 19, 2018

A Buzzcock Conjecture

Just give me an excuse to make music-lyric (or certain other pop culture) jokes — any excuse at all.

You can also take a look on Twitter.

Wednesday, July 18, 2018

Tales from the ArXiv: Don't Feed Random Walkers After Midnight

There is a new paper on arXiv about reactive random walkers.

Quoting from the abstract: "The model is highly versatile, as the motion of the walkers can be fed on topological properties of the nodes..."

Comment: But don't feed them after midnight.

Dodgers Trade for Manny Machado!

It's now official (after some increasingly hot rumors, especially yesterday at the All-Star Game): The Dodgers have traded for Manny Machado, the biggest ticket on this season's trade market. Hell yes!!!!

With Corey Seager out for the year, having Machado to play shortstop the rest of the year is most excellent indeed!

Tuesday, July 17, 2018

Medieval Fantasy City Generator

This is so cool!

I also wonder if it uses any generative-model ideas from urban analytics and/or complex systems?

(Tip of the cap to Dungeons and Dragons Memes.)

Monday, July 16, 2018

Heart and Caffeine Plushies

I bought Heart a couple of months ago, and Caffeine just arrived today.

"Message-Passing Methods for Complex Contagions"

Here is the published version of a the chapter that James Gleeson and I wrote for the book Complex Spreading Phenomena in Social Systems, which was edited by Sune Lehmann and YY Ahn. You can also find preprint versions of many chapters available for free on this website.

XKCD: "Negative Results"

I am amused.

Friday, July 13, 2018

Creating Wikipedia Entries for Underrepresented Scientists and Engineers

As described in this article, physicist Jess Wade has been doing incredible work on writing new Wikipedia entries.

Wednesday, July 11, 2018


If I recall correctly, I encountered this one when purchasing theatre tickets at a certain venue in Oxford.

Real-Life Elliptical Billiard Table

I approve!

Now we just need real-life Sinai and stadium billiards (and, of course, a mushroom billiard, to make Lyonia happy).

(Tip of the cap to Alex Bellos.)

Update: The table pictured in the article appears to be a circle, rather than a more general ellipse.

Algorithmic Author Ordership

I am amused. :)

Tuesday, July 10, 2018

Awesome Close-Up Photos of Snails

You can snail, you can snail...

(Tip of the cap to Invisible Scientist.)

Thursday, July 05, 2018

My Eponymous Agent-Based-Model (ABM) Simulator

(Tip of the cap to Sang Hoon Lee.)

Tuesday, July 03, 2018

"My" Eponymous Band

As some of you know, there is a band called Mason Porter. We both show up near the top of Google search for "Mason Porter" (and similar items). Over the years, I have been tagged on several Twitter posts instead of them. I am also followed by a few random people who are interested in folk and bluegrass music, and I have even had some good-natured Twitter battles with the band when I visit Philadelphia.

And now, on this occasion, even the band itself accidentally tagged me in their Facebook post instead of themselves!

Rock on! ("Folk on?")

One of these years, I seriously need to crash one of their shows with a short mathematics lecture.

Monday, July 02, 2018

"International Conference on Newfangled Methods"


Sunday, July 01, 2018

What Happens in Newcastle Stays in Newcastle (2018 Edition)

I've been visiting friends in Newcastle the last couple of days.

Thursday, June 28, 2018

RIP Harlan Ellison (1934–2018)

The great writer Harlan Ellison (who contributed much to science fiction, as well as other genres) died today.

Here is a picture with him at Dragon*Con in 2003. He complimented me on the shirt I was wearing, and rolled his eyes to signal to me (while I was waiting patiently at the front of the line) that the person in front of me in line for his autograph (who gave him tons and tons of things to sign) was an idiot. For me, he signed a well-read copy of the 35-year retrospective of his work, and he agreed to be in the picture below. Unlike recent Dragon*Cons, Ellison's autograph was free. He seemed to appreciate the fact that I had obviously read the book that I asked him to sign.

Update: Here is an obituary from The Nerdist.

Tuesday, June 26, 2018

Another Living Network

Here is another living network, as one can see especially prominently in the right panel.

Other examples of living networks are fungal networks.

(Tip of the cap to Jessica Rosenkrantz.)

Monday, June 25, 2018

"Detecting Sarcasm with Deep Convolutional Neural Networks"

I think they found it.

(Tip of the cap to Peter Rothman.)

Sunday, June 24, 2018

Yet Another Amazing Tiling from Tiling Bot

Tiling Bot has been producing lots of amazing (and often gorgeous) tilings on Twitter. Today's is one of my favorites.

I strongly recommend looking through Tiling Bot's feed.

Saturday, June 23, 2018

What Happens in Oxford Stays in Oxford

I arrived in Oxford last Sunday and will be here for a while, staying in Somerville and hanging out with my peeps (including some of my former students) from College as well as the Mathematical Institute. It's great to still be part of the extended family!

I'll also be participating and speaking at Howison-fest, a workshop in honor of Sam Howison's 60th birthday.

Thursday, June 21, 2018

"FU" Stands for "Fundamental Unit"

Naturally, when I see "FU", the first term that comes to mind is "fundamental unit".

Remember: "FUs are biologically well defined".

This screenshot is from this new paper.

(Tip of the cap to Alex Vespignani.)

Ground Control to Major Tom: Perfect Photographic Timing

I approve!

Wednesday, June 20, 2018

Poincaré Disk: Fantasy Edition

I love it!

A Bulging Visual Illusion

This is a great visual illusion!

(Tip of the cap to Ben Orlin.)

Scholarship: Part of the Scientific Reward System

I may have been slightly snarky. :)

Tuesday, June 19, 2018

Apple Seismology

Here is a cool 'Quick Study' about "apple seismology".

Quoting the article's lead: Just as an earthquake’s seismic waves reveal properties of Earth’s interior, elastic surface waves on an apple can tell us about what’s going on inside the fruit.

This research may be a contender for an Ig Nobel prize.

Update: Apple seismology was discussed originally in a 1973 mathematical modeling paper by J.R. Cooke and Richard Rand. (This paper is cited in the Physics Today article above.)

An Alternative to a Faculty Retreat

Instead of having a Faculty Retreat, why don't we have a Faculty Victory this time?


Hitting a Major League Home Run Before One's First Major League Home Run

"Yesterday's" home run by Juan Soto, in a game that was suspended May 15th and completed yesterday, will be part of a great trivia question in the future.

Quoting from the article to which I linked:

On Monday, the Washington Nationals rookie crushed a tiebreaking, pinch-hit, two-run homer against the New York Yankees in the continuation of a game that started May 15 — five days before his big league debut.

According to the Elias Sports Bureau, Soto's blast will not be considered his first major league homer, but it will be counted as a home run hit on May 15.

Saturday, June 16, 2018

"Female Drosophila melanogaster Respond to Song-Amplitude Modulations"

One of my papers came out in final published form a few days ago. Here are some details. (Also see the paper's supplementary material for an interview with the first author, my former D.Phil. student Birgit Brüggemeier.)

Title: Female Drosophila melanogaster Respond to Song-Amplitude Modulations

Authors: Birgit Brüggemeier, Mason A. Porter, Jim O. Vigoreaux,and Stephen F. Goodwin

Abstract: Males in numerous animal species use mating songs to attract females and intimidate competitors. We demonstrate that modulations in song amplitude are behaviourally relevant in the fruit fly Drosophila. We show that Drosophila melanogaster females prefer amplitude modulations that are typical of melanogaster song over other modulations, which suggests that amplitude modulations are processed auditorily by D. melanogaster. Our work demonstrates that receivers can decode messages in amplitude modulations, complementing the recent finding that male flies actively control song amplitude. To describe amplitude modulations, we propose the concept of song amplitude structure (SAS) and discuss similarities and differences to amplitude modulation with distance (AMD).

Thursday, June 14, 2018

Adrián Beltré Now has More Hits than All Other Non-US-Born Players

Adrián Beltré now has more MLB hits than any other non-US-born player who ever played the game!

He passed Ichiro in the game that ended a few hours ago.

Saturday, June 09, 2018

What Happens in Paris Stays in Paris

I am at the airport. I'll be heading to Paris for NetSci 2018!

Sunday, June 03, 2018

Excellent Notation for Predator–Prey Dynamics

I approve!

(Tip of the cap to Karen Daniels.)

Triumphant Return of The Power Law Shop

Saturday, June 02, 2018

Jack and Jill had Issues

Mathematics is an Experimental Science


(Tip of the cap to Steve Strogatz.)

Friday, June 01, 2018

A Brief Celebration of #NationalDonutDay

Thursday, May 31, 2018

Tales from the ArXiv: "Calculating Spherical Harmonics Without Derivatives"

There is a new paper on the arXiv that apparently includes a new way of calculating spherical harmonics.

A part that some of you may find interesting is the pedagogical discussion at the beginning of Section 5, which starts: "Historically, there are five ways that spherical harmonics can be derived."

The one that is easiest (by far) for me to understand is the oldest method, which is by solving the differential equation. But I am mathematically inclined, and people with more physical intuition may prefer other methods.

(People who are more comfortable than I am with Lie manipulations may also prefer other approaches.)

Anyway, I appreciate the discussion in this paper.

Sunday, May 27, 2018

"Can Multilayer Networks Advance Animal Behavior Research?"

The final version of a new paper of mine now has its final coordinates in a journal. Here are some details.

Title: Can Multilayer Networks Advance Animal Behavior Research?

Authors: Matthew J. Silk, Kelly R. Finn, Mason A. Porter, and Noa Pinter-Wollman

Abstract: Interactions among individual animals — and between these individuals and their environment — yield complex, multifaceted systems. The development of multilayer network analysis offers a promising new approach for studying animal social behavior and its relation to eco-evolutionary dynamics.

Thursday, May 24, 2018

Innovative Pitching Usage: Micro-Starts by Relievers

The Rays started playing around with an interesting innovation in their pitcher usage in a recent series against the Angels: They started a reliever for one inning to face the tough top of their lineup, and then they brought in their scheduled "starter" for the second inning.

The Rays are doing this again in their upcoming series against the Orioles.

I think there is a lot of traction for more of this, though it will depend on a team's rotation (e.g., if you have one like the Astros, this is probably not as helpful as for the Rays), player, player egos, and so on.

Thursday, May 17, 2018

"The Pole Arm of Archaeology" and Other Epic Scholar Visualizations

Dan Hicks posted some epically bad scholar visualizations as a Twitter thread. My favorite one is The Pole Arm of Archaeology, which is about as epic as it sounds. ;)

(Tip of the cap to Brian Cox.)

Tuesday, May 15, 2018

'Working Paper' in Collaboration with International Monetary Fund: "Evolution of the Global Financial Network and Contagion: A New Approach"

A 'working paper' from a collaboration with folks from the International Monetary Fund (IMF) came out today. You can download it from this website. We also hope to submit a version of this work to a journal for publication. Here are some details.

Title: Evolution of the Global Financial Network and Contagion: A New Approach

Authors: Yevgeniya Korniyenko, Manasa Patnam, Rita Maria del Rio-Chanon, and Mason A. Porter

Abstract: This paper studies the interconnectedness of the global financial system and its susceptibility to shocks. A novel multilayer network framework is applied to link debt and equity exposures across countries. Use of this approach—that examines simultaneously multiple channels of transmission and their important higher order effects—shows that ignoring the heterogeneity of financial exposures, and simply aggregating all claims, as often done in other studies, can underestimate the extent and effects of financial contagion.The structure of the global financial network has changed since the global financial crisis, impacted by European bank’s deleveraging and higher corporate debt issuance. Still, we find that the structure of the system and contagion remain similar in that network is highly susceptible to shocks from central countries and those with large financial systems (e.g., the USA and the UK). While, individual European countries (excluding the UK) have relatively low impact on shock propagation, the network is highly susceptible to the shocks from the entire euro area. Another important development is the rising role of the Asian countries and the noticeable increase in network susceptibility to shocks from China and Hong Kong SAR economies.

Compilation of "Awesome" #BadStockPhotosOfMyJob

These stock photos of jobs (with much focus on scientific ones) are indeed hilariously bad.

Mathematics and physics get the familiar, cheesy writing-in-the-mirror treatment in some of these.

(Tip of the cap to Justin Howell.)

Fun Fact: My First Publication was a Dungeons & Dragons Character!

Saturday, May 12, 2018

You Wouldn't Like These Functions When They're Angry

There is a family of special functions called Anger functions. You wouldn't like them when they're angry.

Here is the context: Physics Today has agreed to publish an obituary for Norman Zabusky, so I needed to find some information that they require to be part of it. This led me to Norman's PhD thesis, which I found online. It briefly mentions something called Lommel polynomials, with which I wasn't familiar. The definition in a thesis appendix was terse — it's not exactly an important part of the thesis — so I looked at Wikipedia, and I kept seeing links to special functions that weren't familiar to me, and I have followed a couple of them. Anger functions are one family.

These various special functions are closely related to Bessel functions.

Thursday, May 10, 2018

Meaningless Connections and Empty Entities

And I spend lots and lots of time studying these things, including in the context of applications like social media. ;)

(Tip of the cap to Jane Shevtsov.)

Wednesday, May 09, 2018

The Pulse of Manhattan


Taking the First Stab at "Taking the First Stab"

I couldn't find this with a simple Google search, but if you think about it, the origin of the phrase "take the first stab" has to be rather violent.

Maybe a nice piece of art to go with somebody starting to write the initial draft of an academic paper would be a picture of a scientist quite literally taking an initial stab through a pile or papers or perhaps through a laptop.

(If anybody has a favored website for etymology and similar matters, please let me know. I was hoping my global search would turn up a good answer on one of those pages.)

And, by all means, somebody should take the first stab at answering my query.

Video of my Tutorial in Paper-Writing in Applied Mathematics

Here is a video of my recent (4/20) tutorial on paper-writing in applied mathematics.

You can also download the slides.

I hope that people find it helpful!

Tuesday, May 08, 2018

Important Paper on Seussian Configurations of Random-Graph Models

In network science, it is with very good reason that one should speak of "a" configuration model rather than "the" configuration model. To see an excellent discussion of this and related issues, be sure to go through this paper by Bailey Fosdick, Daniel Larremore, Joel Nishimura, and Johan Ugander.

Title: Configuring Random Graph Models with Fixed Degree Sequences

Authors: Bailey K. Fosdick, Daniel B. Larremore, Joel Nishimura, and Johan Ugander

In 2014, Aaron Clauset, David Kempe, and I (with help from Dan Larremore) organized a Mathematics Research Community in Network Science.

In addition to creating a network of network scientists from diverse backgrounds, some work was started there, and today the published version of what is in my opinion an extremely important paper has come out in final form in SIAM Review's 'Research Spotlights' section. I am, of course, talking about the aforementioned paper.

I'm very happy indeed for such excellent work to arise from this.

Congratulations to authors Bailey Fosdick, Daniel Larremore, Joel Nishimura, and Johan Ugander for creating this awesome paper!

I am posting this with an absolutely lovely Seussian picture from an arXiv version of the paper. This picture doesn't appear to have made the cut for the published piece. In addition to its wit and whimsy, a really great thing about the picture and its accompanying verse is that it also encodes the main message of the paper.

Note: I am on the editorial board of the Research Spotlights section of SIAM Review, but I had nothing whatsoever to do with the handling of this paper.

Friday, May 04, 2018

Albert Pujols gets his 3000th Career Hit!

Albert Pujols collected his 3000th career hit tonight, becoming the 32nd member of the club. He is one of four Major Leaguers with at least 600 homeruns and at least 3000 hits.

Thursday, May 03, 2018

Awesome Google Doodle

The new Google Doodle, which celebrates Georges Méliès, is really, really cool. Go interact with it!

Tuesday, May 01, 2018

Our Memorial Article for Norman J. Zabusky (1929–2018)

Along with David Campbell and Alan Newell, I have written a memorial article for my collaborator Norman Zabusky, who died in February. It was posted online earlier today.

Sunday, April 29, 2018

Crib Notes on a Fingernail (with \latex Notation)

If I were going to put mathematical formulas on my fingernail as crib notes, I'd also use \latex notation. :)

My favorite is the use of " \; ", which would allow the cheating student being modeled by the picture to ensure legible symbol spacing when writing exam solutions.

Saturday, April 28, 2018

Number of Spaces and Periods

Let the debating commence.

Tuesday, April 24, 2018

Balloon Skeleton Animals

These are amazing!

Monday, April 23, 2018

"Nanoptera in a Period-2 Toda Chain"

One of my papers recently came out in final form (with its volume and all of its other publication coordinates). Here are some details.

Title: Nanoptera in a Period-2 Toda Chain

Authors: Christopher J. Lustri and Mason A. Porter

Abstract: We study asymptotic solutions to a singularly perturbed, period-2 Toda lattice and use exponential asymptotics to examine "nanoptera," which are nonlocal solitary waves with constant-amplitude, exponentially small wave trains. With this approach, we isolate the exponentially small, constant-amplitude waves, and we elucidate the dynamics of these waves in terms of the Stokes phenomenon. We fi nd a simple asymptotic expression for these waves, and we study con figurations in which these waves vanish, producing localized solitary-wave solutions. In the limit of small mass ratio between the two types of particles in the lattice, we derive a simple antiresonance condition for the manifestation of such solutions.

Thursday, April 19, 2018

Manifolds Lying in a Higher-Dimensional Space

We often view manifolds as lying in some higher-dimensional space, but shouldn't we also consider ones that are telling the truth? 🤔

Tuesday, April 17, 2018

Tales from the ArXiv: "26 pages and 10 gorgeous figures"

The authors of this paper, in the comments field, advertised their paper as having "26 pages and 10 gorgeous figures".

They’re not bad. I wouldn’t call them gorgeous, though.

Resistance is for the Birds

Damn right. #resist

Sunday, April 15, 2018

Shopping for Groceries and Solving the Reimann Hypothesis

I love it!

Monday, April 09, 2018

Awesome Journal Idea: Young-Researcher, First-Author Interviews for Accepted Papers

Today, one of my papers was accepted by Biology Open, with which I didn't previously have any experience.

As part of their correspondence today, they also let the first author (my former doctoral student) know about the option of a young-scientist, first-author spotlight. They wrote the following (which you can also find on their website):

Congratulations on acceptance of your article in Biology Open. To help early-career researchers promote themselves alongside their papers, we have launched a series of interviews with the first authors of a selection of papers published in BiO. If you would like to be included in this interview series, please tell us more about yourself by answering the questions below. You can answer all or just some of the questions, and you may also suggest additional questions and provide your answers to them if you wish.

How interesting! I have never seen a journal do this before. What a great idea! We really need to do something like this in the mathematics and physics communities.

Here are their suggested questions:

What is your scientific background and the general focus of your lab?

How would you explain the main findings of your paper to non-scientific family and friends?

What are the potential implications of these results for your field of research?

What has surprised you the most while conducting your research?

What, in your opinion, are some of the greatest achievements in your field and how has this influenced your research?

What changes do you think could improve the professional lives of early career scientists?

What's next for you?

They then added the following:

So that we can create a short biography to accompany your interview, please ensure that you include your job title, the name of the Principal Investigator of your lab, your contact address and a one-line synopsis of your research interests. Include your Twitter handle, if you have one, so we can tag you in any related tweets.

They also asked for a picture of the first author and "a particularly striking, interesting or unusual image" from their research (along with a caption describing it).

Thursday, April 05, 2018

Tales from the ArXiv: Centenary of Emmy Noether's Invariante Variationsprobleme

This article commemorates the centenary of Emmy Noether's article Invariante Variationsprobleme.

Title: On the Wonderfulness of Noether's Theorems, 100 Years Later, and Routh Reduction

Author: Raphaël Leone

Abstract: This paper is written in honour of the centenary of Emmy Amalie Noether's famous article entitled Invariante Variationsprobleme. It firstly aims to give an exposition of what we believe to be the most significant and elegant issues regarding her theorems, through the lens of classical mechanics. Despite the limitation to this field, we try to illustrate the key ideas of her work in a rather complete and pedagogical manner which, we hope, presents some original aspects. The notion of symmetry coming naturally with the idea of simplification, the last part is devoted to the interplay between Noether point symmetries and the reduction procedure introduced by Edward John Routh in 1877.

Sunday, April 01, 2018

XKCD: "Right Click"

The new XKCD is another one of those that needs to be mapped out. I'm looking forward to seeing the resulting network. We should calculate some properties of it. :)

While navigating the menus, I managed to get eaten by a grue.

There are errors in some of the D & D categorizations.

Some April Fool's Day Stuff

I'll try to keep a running tab of some of the April Fool's Day stuff I notice. As I write this, I haven't tried to look very much.

The first one that I want to mention is ThinkGeek's catalog. (Tip of the cap to Jennifer Ouellette.)

As usual, there are some special papers on the arXiv, including this one and this one.

Here is another joke arXiv paper. (Tip of the cap to Chad Topaz.)

Here is a roundup of Google's jokes, including the ability to play "Where's Waldo?" on Google Maps.

Saturday, March 31, 2018

Research Soundtrack

There are rare times when research feels like "Chariots of Fire", and others (usually) when it's more like "March of the Toreadors".

Friday, March 30, 2018

A Pitch for My New Novel

As determined from my dice (and this handy chart), here is the pitch for my new novel: A dystopian fairy tale about a dissatisfied doctor's vacation to expose her social media addiction.

By the way, my d30 (where I rolled again for any results from 27–30) rolled 20 three times during this process, and its only roll below 18 was a single 14, with all but those two rolls in the 20s (including a few of at least 27). Clearly, this is a damage die.

Also, can we get a chart like this for cover letters and grant proposals, please?

P.S. A social media addiction should be contrasted with an antisocial media addiction.

(Tip of the cap to Jennifer Ouellette.)

Wednesday, March 28, 2018

Cover Letters When Responding Reviewers

This "sample cover letter" is hilarious!

I read this before at some point, and it's still really funny now. (And also way too close to the truth.)

Tuesday, March 27, 2018

"Interval Signatures of Celebrities and Researchers on Twitter"

In case you ever wanted to compare my tweeting behavior to that of Lance Armstrong and other celebrities (and several network and data scientists), here is your chance.

It's always nice to be analyzed (for my tweeting behavior) alongside luminaries like Katy Perry, Shaquille O'Neal, and Steve Martin. Lots of my peeps from network and data science are also put under the data-analytic microscope (or perhaps I should write 'mesoscope') on this page.

The Perils of Generating Functions (and Submitting a Note from a Parent with an Exam)

When I taught Math 1d, my exam instructions included a joke line that went something along the lines of "You may also use a note from your mother, though you won't need one." One student (and fellow Caltech undergrad) actually got her mother to write this note, which is fantastic (despite the threats against both Lloyd House and the Los Angeles Dodgers).

I had this posted on my door at Georgia Tech when I was a postdoc, and I found the note a year ago today when I was going through an old spiral notebook.

Sunday, March 25, 2018

Congratulations to Dr. Se-Wook Oh!

Congratulations to my D.Phil. student, Dr. Se-Wook Oh, who has officially earned his doctorate from the Mathematical Institute at University of Oxford. (Jon Chapman was nominally added as a local co-supervisor after I moved to UCLA.) His thesis, in corrected form, has officially been approved.

The title of Se-Wook's thesis is Complex Contagions with Lazy Adoption. You can read about some of Se-Wook's work in our joint paper, which was published recently in Chaos.

Tuesday, March 20, 2018

In Conclusion, Hilarity Ensues.

"Hilarity ensues." is acceptable for the Conclusions section of a paper, right?

What Happens in Provo Stays in Provo

I am at the airport — with a 165-minute delay (sigh...) in my flight — to visit the mathematics department at BYU. I am being hosted by Emily Evans, who is on their faculty and is also a friend of mine from college.

I will somehow deal with the fact that I am not allowed to have coffee on campus. :)

Sunday, March 18, 2018

Algorithms in the Form of IKEA Instructions

I think my life could not possibly have been complete without seeing algorithms presented in the form of IKEA instructions. I am highly amused. :)

(Tip of the cap to Lior Pachter.)

We Kid the Statisticians Because We Love Them


(Tip of the cap to Kerstin Nordstrom.)

Saturday, March 17, 2018

Some Really Old Boardgames

Take a look at this article about some really old boardgames (and one from 1940), including one from the 17th century, that are in a collection in the Houghton Library.

I like the cover of "The Magic Ring". :)

(Tip of the cap to Gabrielle Birkman.)

Society for Impure Mathematics (SIM)

I am an active member of SIAM, the Society for Industrial and Applied Mathematics.

Here's a Fun (Alternative) Fact: The Society for Industrial and Applied Mathematics used to be known as "Society for Impure Mathematics" (SIM), because those of us who do applied mathematics are less pure than other types of mathematicians, bless their hearts.

But perhaps this great organization really ought to change its name to "Society for Impure Mathematics", to appease the theoretical mathematicians who like to call themselves "pure" mathematicians.

As you may have gathered, I find the phrasing "pure mathematics" to be incredibly demeaning towards applied mathematics and applied mathematicians. (The term "unadulterated mathematics" is even worse, so I suppose that my subject of choice is "adulterated mathematics".) I really dislike being considered impure, by implication of the term in use. "Pure mathematics" should really be called "theoretical mathematics", just like in every other science.

Additionally, here are two of my tweets on this and related subjects.

Update: I corrected the acronym (I had written "SIP"), because apparently I am having a problem with English today.

Update: If we want to preserve the acronym SIAM and don't mind a bit of redundancy, it can stand for "Society for Impure and Adulterated Mathematics". :)

Visual Illusion: Snakes on a Plane

Enough is enough. I've had it with these ****** illusory snakes on this ******-****** plane.

(Tip of the cap to Maggie Koerth-Baker.)

Friday, March 16, 2018

Old Article: "On the Fracture of Pencil Points"

I got my first taste of solid mechanics (and fracture mechanics) as a kid when attempting to use 'Number 2' pencils, on which I gave up rather quickly. Once they break once, they will soon break again. I switched to "mechanical pencils" (I like the .07 size) when I was very young.

Here is an old article on pencil-tip fracture (by Henry Petroski). The picture below, which comes from an even earlier article, sets up the the geometry of a pencil tip.

(I was thinking about this because a 'Number 2' pencil showed up in The Grimm Legacy, which I am currently reading.)

Thursday, March 15, 2018

RIP Philip J. Davis (1923–2018) and Writing Uncountably Many Articles

Philip J. Davis, an applied mathematician and very prolific writer, died on Tuesday.

I have a pet peeve in the above obituary: Don't write sentences like "He wrote countless books, articles, and book reviews imbued with his personal perspective." in the obituary of a mathematician, especially if he is an analyst (with much work in numerical analysis, in this case). Trust me: it's countable (and, actually, it's finite).

For most of us, we'll be more familiar with the many essays and (especially) book reviews that Davis wrote for SIAM News.

(Tip of the cap to the SIAM Twitter account.)

"Title of a Paper"

Update: It turns out that I did this so quickly that I mixed my Oxford and UCLA affiliations. Oops.

Tuesday, March 13, 2018

Best. Erratum. Ever.

Because they have so many coauthors, one letter wrong in a name led to this. :)

(Tip of the cap to Nalini Joshi, whose 'liking' of this tweet led me to find it.)

Saturday, March 10, 2018

Playing Mario Kart on Google Maps to Celebrate Mario Day!

In celebration of Mario Day (Mar 10), Google is letting people play a version of Mario Kart on Google Maps.

I have a key question: Where are the best places to inflict lightning bolts on people?

In conclusion, come get some!

(Tip of the cap to Gabrielle Birkman, who indicates that there are places to get banana peels and turtle shells.)

The Multiplex Social–Slayage Network of Buffy the Vampire Slayer

Here is the multiplex social–slayage network of Buffy the Vampire Slayer.

This figure is definite fodder for talks. Also, if somebody sets up the adjacencies, we should compute some centrality and versatility measures.

Friday, March 09, 2018

Pure Evil Versus Applied Evil

The new SMBC is brilliant! I love the caption: "Most of the time when people call something pure evil, they're actually talking about applied evil." ;)

Feedback on Homework Assignments: Getting the Important Stuff Right

As part of the feedback that I once gave to Teaching Committee (to be passed on to the lecturer) on some of the mathematics material in Oxford, I once wrote: "dynamics: The Roadrunner's name is incorrect on homework sheet 2."

You've got to get the important stuff right.

(My submitted feedback also included more substantial comments.)

I also told the lecturer about this in person, of course. :)


New Word Proposal: "Scientificially"

I asked a student if a paper draft of mine passes muster with her "scientificially".

It was just a typo, but I may have to adopt this as a new word for when somebody does something artificial in science.

Example usage: "Those data were estimated scientificially to follow a power law."

Wednesday, March 07, 2018

Video project: "Faces of Women in Mathematics"

Last month, Irina Linke (Director) and Eugénie Hunsicker (Producer) collected videos of women mathematicians, and today they released their compilation video.

Quoting the project page: "In February 2018, women mathematicians from all over the world responded to a call for clips in which they were asked to introduce themselves. The result includes 146 clips of 243 women mathematicians from 36 different countries and speaking 31 different languages. Supported by the Committee for Women in Mathematics of the International Mathematical Union."

Take a look at the video!

I met Eugénie, a fellow Somervillian, at last summer's Somerville mathematics reunion (and informal Erdmann-fest). I just found out that she is also a fellow Project NExTer (i.e., a fellow 'dot').

Tuesday, March 06, 2018

"Hyperchaos" in the White House

I saw "CHAOS" trending on Twitter this morning, so I automatically looked it up, before seeing that it was about politics and then moving on to something else.

And now I see this article, which predominantly consists of an interview with nonlinear dynamicist (and pioneer of chaos) Jim Yorke, including discussions about both mathematical chaos and hyperchaos.

Here is how the part with Yorke begins: "That's not chaos, according to James A. Yorke, Distinguished University Professor of Mathematics and Physics at the University of Maryland at College Park." It goes on from there.

Just think about it: Jim Yorke, an expert in chaotic dynamics, was interviewed by CNN about Donald Trump, precisely because of the former's expertise in mathematical chaos. Yup, we've gone full Illuminati.

(Tip of the cap to Bruno Eckhardt and fuzzy sweatshirt particle.)

Monday, March 05, 2018

"Making Sense of Complexity": A Very Nice Introductory Comic Strip

Sarah Firth's comic strip, Making Sense of Complexity, provides a very nice introduction to complex systems.

Friday, March 02, 2018

Important Advice from Lego Grad Student to Prospective Graduate Students

Pay attention to this excellent advice from Lego Grad Student.

Reaction: YES! YES! A million times YES! (And, for the top tweet, I would change "seriously consider" to "absolutely go to".)

P.S. Lego Grad Student is awesome.

Playing "Soliton" in "Scrabble" (Lexulous)

Take a look at what I just played in “Scrabble” (Lexulous).

Proposal: Use Computational Topology to Study Aversion to Pictures of Holes

Clearly, we need to use topological data analysis (in which one tries to algorithmically compute things like holes and their generalizations) to study aversions to images of clusters of holes.

For science!

Thursday, March 01, 2018

Is 1 the Loneliest Number?

I like (several renditions of) the song "One (is The Loneliest Number)", but I get irked every time I hear following line "One is a number divided by two", because that is just a trivial existence statement.

(Some — most? — versions of the song actually have the line "One is the number divided by two", which is even worse, because of the "the".)

I suppose that this doesn't bother anybody else?

Is There a Mathematical Formula for How Long it Takes for a Child to Ask "Are We There Yet?"?

Well, I find the formula to be rather dubious, though I am highly amused to see it.

I was looking at Dwight Barkley's Wikipedia page, and I noticed that apparently he is also known for deriving an equation to estimate how long it will be until a child in a car asks the question "are we there yet?"

You can read about it (and see the equation) in this short article.

"Complex Contagions with Timers"

A new paper of mine just came out today. This paper was such a pain to write and the page proofs were also a royal pain, so it's a relief that it's finally out. Here are the details.

Title: Complex Contagions with Timers

Authors: Se-Wook Oh and Mason A. Porter

Abstract: There has been a great deal of effort to try to model social influence—including the spread of behavior, norms, and ideas—on networks. Most models of social influence tend to assume that individuals react to changes in the states of their neighbors without any time delay, but this is often not true in social contexts, where (for various reasons) different agents can have different response times. To examine such situations, we introduce the idea of a timer into threshold models of social influence. The presence of timers on nodes delays adoptions—i.e., changes of state—by the agents, which in turn delays the adoptions of their neighbors. With a homogeneously-distributed timer, in which all nodes have the same amount of delay, the adoption order of nodes remains the same. However, heterogeneously-distributed timers can change the adoption order of nodes and hence the “adoption paths” through which state changes spread in a network. Using a threshold model of social contagions, we illustrate that heterogeneous timers can either accelerate or decelerate the spread of adoptions compared to an analogous situation with homogeneous timers, and we investigate the relationship of such acceleration or deceleration with respect to the timer distribution and network structure. We derive an analytical approximation for the temporal evolution of the fraction of adopters by modifying a pair approximation for the Watts threshold model, and we find good agreement with numerical simulations. We also examine our new timer model on networks constructed from empirical data.

Tuesday, February 27, 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.)

Some Very Cool Outdated Words

This is brilliant. (I have heard of some of these before.) We need to bring back some of these words.

Sunday, February 25, 2018

Gummy Bear Genetics

Stripe orientation appears to be independent of genetic inheritance in Gummy Bears.

Thursday, February 22, 2018

Alan Kay's 1972 Vision of the Personal Computer

This is very, very cool!

"Opinion Formation and Distribution in a Bounded-Confidence Model on Various Networks"

Another of my papers came out in final form today. This work was led by my former (and excellent) undergraduate student Flora Meng. Here are the details.

Title: Opinion Formation and Distribution in a Bounded-Confidence Model on Various Networks

Authors: X. Flora Meng, Robert A. Van Gorder, and Mason A. Porter

Abstract: In the social, behavioral, and economic sciences, it is important to predict which individual opinions eventually dominate in a large population, whether there will be a consensus, and how long it takes for a consensus to form. Such ideas have been studied heavily both in physics and in other disciplines, and the answers depend strongly both on how one models opinions and on the network structure on which opinions evolve. One model that was created to study consensus formation quantitatively is the Deffuant model, in which the opinion distribution of a population evolves via sequential random pairwise encounters. To consider heterogeneity of interactions in a population along with social influence, we study the Deffuant model on various network structures (deterministic synthetic networks, random synthetic networks, and social networks constructed from Facebook data). We numerically simulate the Deffuant model and conduct regression analyses to investigate the dependence of the time to reach steady states on various model parameters, including a confidence bound for opinion updates, the number of participating entities, and their willingness to compromise. We find that network structure and parameter values both have important effects on the convergence time and the number of steady-state opinion groups. For some network architectures, we observe that the relationship between the convergence time and model parameters undergoes a transition at a critical value of the confidence bound. For some networks, the steady-state opinion distribution also changes from consensus to multiple opinion groups at this critical value.

Wednesday, February 21, 2018

Mathematical Haiku

(Thanks to Paul Glendinning for the Twitter 'mention', from which I learned that my haiku made it into the article.)

What Happens in Knoxville Stays in Knoxville

I'll be heading to my first visit to Tennessee to participate in a NIMBioS working group at University of Tennessee.

I'd try to link to a relevant website, except that my internet connection at the airport is glacially slow, so I'm not going to even try for now. We'll be formulating some forward-looking big problems in network neuroscience to think about together and then hopefully start thinking deeply about and trying to solve.

Update: Here is the link to our working group.

Tuesday, February 20, 2018

Danger in the Nth Dimension: A 1950s Comic with N = 4

The cover of this 1950s comic book is adorable.

And this was with only a 4th dimension!

This will be great fodder for some math and physics talks... "NO! Don't enter that manifold!"

(Tip of the cap to James Gleick.)

Monday, February 19, 2018

Tales from the ArXiv: Building on "Seminal but Laconic" Findings

I am highly amused by one of the sentences in the abstract of this paper, which is called "Systematic elimination of Stokes divergences emanating from complex phase space caustics".

The sentence in the abstract reads as follows: Building on the seminal but laconic findings of Adachi, we show that the deviation from second order can be used to rigorously determine the Stokes lines and therefore the region of the space that should be removed.

I think I need to steal the first part of that sentence, and I know that I have felt that way on many occasions (e.g., with respect to work by Nesterenko) in my career.

"Neither Global nor Local: Heterogeneous Connectivity in Spatial Network Structures of World Migration"

One of my papers, which has had a DOI for about half a year, finally has its final publication coordinates. Notably, this is my first paper in a sociology journal. Here are some details.

Title: Neither Global nor Local: Heterogeneous Connectivity in Spatial Network Structures of World Migration

Authors: Valentin Danchev and Mason A. Porterc

Abstract: For a long time, geographic regions were considered the dominant spatial arbiter of international migration of people. However, since the late 1970s, many scholars have argued that movements reach beyond contiguous regions to connect distant, dispersed, and previously disconnected countries across the globe. The precise structure of world migration, however, remains an open question. We apply network analysis that incorporates spatial information to international migration-stock data to examine what multilateral structures of world migration have emerged from the interplay of regional concentration (local cohesion)and global interconnectedness (global cohesion) for the period 1960–2000. In the world migration network (WMN), nodes represent countries located in geographic space, and edges represent migrants froman origin country who live in a destination country during each decade. We characterize the large-scale structure and evolution of the WMN by algorithmically detecting international migration communities (i.e., sets of countries that are densely connected via migration) using a generalized modularity function for spatial, temporal, and directed networks. Our findings for the whole network suggest that movements in the WMN deviate significantly from the regional boundaries of the world and that international migration communities have become globally interconnected over time. However, we observe a strong variability in the distribution of strengths, neighborhood overlaps, and lengths of migration edges in the WMN. This manifests as three types of communities: global, local, and glocal. We find that long-distance movements in global communities bridge multiple non-contiguous countries, whereas local (and, to a lesser extent, glocal) communities remain trapped in contiguous geographic regions (or neighboring regions) for almost the whole period, contributing to a spatially fragmented WMN. Our findings demonstrate that world migration is neither regionally concentrated nor globally interconnected, but instead exhibits a heterogeneous connectivity pattern that channels unequal migration opportunities across the world.