My name is Mason Porter. I am a Professor in the Department of Mathematics at UCLA. Previously I was Professor of Nonlinear and Complex Systems in the Mathematical Institute at University of Oxford. I was also a Tutorial Fellow of Somerville College.
Sunday, December 27, 2020
Brilliant Headstones
RIP Phil Niekro (1939–2020)
Yet another great baseball player has left us this year.
Friday, December 18, 2020
Gollum's Cover of "Nothing Compares 2 U"
Witness the power of deepfakes! If I ever again speak at a workshop about deepfakes, I am whipping out this video.
(This cover needs to be used as a Ride chaser.)
(Tip of the cap to Jennifer Ouellette.)
RIP Peter Neumann (1940–2020)
I had the chance to interact with Peter quite a few times at Oxford. When I knew him, he was concentrating on mathematics history, and I contacted him with a query about some mathematical linguistics (concerning, for example, the use of "topological" only versus both "geometric" and "geometrical"). I knew that Peter was the right person to approach when I wanted to dive deeper than what I was able to do via Google. Here is my 2013 blog entry about that.
Peter was one of the people in Oxford who was always so kind and supportive of me (and, from what I can tell, of many others as well). When I got some pointed negative teaching evaluations, Peter invited me to The Queen's College to dinner to chat about things (and to give gentle advice and so on). But if I am getting rewarded with a dinner like that for messing up, it does create strange incentives. My students in my courses now are certainly benefiting from advice Peter gave me over the years. He also supported me in various fights on committees (we were on Teaching Committee together) and particularly in efforts that I made against "We've always done it this way." comments to try to change things in Oxford's Mathematical Institute.
(Tip of the cap to Card Colm Mulcahy.)
Wednesday, December 16, 2020
"Inference of Edge Correlations in Multilayer Networks"
Title: Inference of Edge Correlations in Multilayer Networks
Authors: A. Roxana Pamfil, Sam D. Howison, and Mason A. Porter
Abstract: Many recent developments in network analysis have focused on multilayer networks, which one can use toencode time-dependent interactions, multiple types of interactions, and other complications that arise in complexsystems. Like their monolayer counterparts, multilayer networks in applications often have mesoscale features,such as community structure. A prominent approach for inferring such structures is the employment of multilayerstochastic block models (SBMs). A common (but potentially inadequate) assumption of these models is thesampling of edges in different layers independently, conditioned on the community labels of the nodes. In thispaper, we relax this assumption of independence by incorporating edge correlations into an SBM-like model. Wederive maximum-likelihood estimates of the key parameters of our model, and we propose a measure of layercorrelation that reflects the similarity between the connectivity patterns in different layers. Finally, we explainhow to use correlated models for edge “prediction” (i.e., inference) in multilayer networks. By incorporating edgecorrelations, we find that prediction accuracy improves both in synthetic networks and in a temporal network ofshoppers who are connected to previously purchased grocery products.
Sunday, December 13, 2020
The Cleveland Baseball Team
Tales from the ArXiv: "A Nudge Framework"
Tuesday, December 08, 2020
RIP Jean-Paul Revel (1931–2020)
À bientôt, Dean Revel.
Update (12/09/20): I am aware of what "À bientôt" means. I used that line because Dean Revel ended all of his articles with it. (So, in case you were worrying about me, there is no need to worry!)
What Happens on Zoom Stays on Zoom
Wednesday, November 25, 2020
XKCD: Linguists (and Probably How My Coauthors Feel)
And don't forget to read the mouseover text.
Sunday, November 22, 2020
A Visual Illusion: Game-and-Watch Style
(Tip of the cap to Sydney Padua.)This may be the strongest optical illusion I’ve ever seen.pic.twitter.com/J8fCqbQUJ1
— Siqi Chen (@blader) November 22, 2020
Sunday, November 15, 2020
Revenge of the Oxford Comma: 2020 Edition
Update your lesson plans, we have a new perfect example for Oxford commas. https://t.co/gm1K8IHkGv
— Laura Ansley (@lmansley) November 14, 2020
(Tip of the cap to Jan van den Heuvel.)
Thursday, November 12, 2020
2020 Most Valuable Player Awards
The top-10 vote-getters in each league are available at the above hyperlinks, and the entire list of vote-getters is available at this web page.
Wednesday, November 11, 2020
2020 Cy Young Awards
Tuesday, November 10, 2020
2020 Managers of the Year
Monday, November 09, 2020
2020 Rookies of the Year
Update: The above page about the NL award doesn't (yet) include the vote totals; you can find them on this page.
Sunday, November 08, 2020
Tuesday, November 03, 2020
Wednesday, October 28, 2020
"Forecasting Elections Using Compartmental Models of Infection"
Title: Forecasting Elections Using Compartmental Models of Infection
Authors: Alexandria Volkening, Daniel F. Linder, Mason A. Porter, and Grzegorz A. Rempala
Abstract: Forecasting elections---a challenging, high-stakes problem---is the subject of much uncertainty, subjectivity, and media scrutiny. To shed light on this process, we develop a method for forecasting elections from the perspective of dynamical systems. Our model borrows ideas from epidemiology, and we use polling data from United States elections to determine its parameters. Surprisingly, our model performs as well as popular forecasters for the 2012 and 2016 U.S. presidential, senatorial, and gubernatorial races. Although contagion and voting dynamics differ, our work suggests a valuable approach for elucidating how elections are related across states. It also illustrates the effect of accounting for uncertainty in different ways, provides an example of data-driven forecasting using dynamical systems, and suggests avenues for future research on political elections. We conclude with our forecasts for the senatorial and gubernatorial races on 6 November 2018 (which we posted on 5 November 2018).
The published version of our paper on forecasting elections using dynamical systems (with compartmental models of infection) is now live: https://t.co/t2IXPBiXSG
— Mason Porter (@masonporter) October 28, 2020
On my webpage: https://t.co/YVfya7jbjy
2020 election forecasts: https://t.co/UQ9MXqAJLh
[cc @al_volkening] pic.twitter.com/CKBbrzt8Vj
Tuesday, October 27, 2020
2020* World Champion Los Angeles Dodgers!!!
Monday, October 19, 2020
"Songs and Lyrics by Tom Lehrer"
Here's some great news!
— Mason Porter (@masonporter) October 19, 2020
Tom Lehrer has released, into the public domain, the lyrics of his songs (also including sheet music for some), including many that you've probably never heard of!!!
There are also alternative lyrics for several songs.
Go here: https://t.co/VKtRztNu1Q
Sunday, October 18, 2020
The Dodgers are Heading to the World Series! (2020 Edition)
The Dodgers have come from behind from a deficit of 3 games to 1 to defeat the Atlanta Braves in game 7 of the National League Championship Series. We're heading to the World Series!
(It hasn't been announced yet as I write this, but I assume that Corey Seager is going to be named the Most Valuable Player of the NLCS.)
Update: As expected, Seager has been named the MVP.
Saturday, October 17, 2020
"Stochastic Block Models are a Discrete Surface Tension"
Tuesday, October 13, 2020
"The Multiplex Nature of Global Financial Contagions"
Our new article came out today. Here are some details.
Monday, October 12, 2020
RIP Joe Morgan (1943–2020)
The baseball world has lost another great one. Second baseman Joe Morgan died today. We have lost a lot of Hall of Famers in the past few weeks (most recently Whitey Ford, before today).
Thursday, October 08, 2020
Dodgers Advance to the National League Championship Series!
The Dodgers have just finished sweeping the San Diego Padres in their National League Division Series matchup and are heading to the National League Championship Series, where they will face (and hopefully defeat) the Atlanta Braves.
Wednesday, October 07, 2020
Some Notable American Physical Society Spring 2021 Prizes
Tuesday, October 06, 2020
2020 Nobel Prize in Physics
Friday, October 02, 2020
RIP Bob Gibson (1935–2020)
Thursday, October 01, 2020
Dodgers Advance to the Division Series!
Monday, September 28, 2020
RIP Jay Johnstone (1945–2020)
Saturday, September 26, 2020
Personal Dice
Thanks very much to @chadtopaz for designing these dice for me!
— Mason Porter (@masonporter) September 27, 2020
It was awesome to wake up to these designs on social media.
I need to get these made in physical form. I especially want something in d20 form. pic.twitter.com/20gx0Vy6fq
Thursday, September 17, 2020
2020 Ig Nobel Laureates
(奚广安) Xi Guang-An, (莫天祥) Mo Tian-Xiang, (杨康生) Yang Kang-Sheng, (杨广生) Yang Guang-Sheng, and (凌显四) Ling Xian Si, five professional hitmen in Guangxi, China, who managed a contract for a hit job (a murder performed for money) in the following way: After accepting payment to perform the murder, Xi Guang-An then instead subcontracted the task to Mo Tian-Xiang, who then instead subcontracted the task to Yang Kang-Sheng, who then instead subcontracted the task to Yang Guang-Sheng, who then instead subcontracted the task to Ling Xian-Si, with each subsequently enlisted hitman receiving a smaller percentage of the fee, and nobody actually performing a murder.
Wednesday, September 16, 2020
"Spatial Applications of Topological Data Analysis: Cities, Snowflakes, Random Structures, and Spiders Spinning Under the Influence"
Title: Spatial Applications of Topological Data Analysis: Cities, Snowflakes, Random Structures, and Spiders Spinning Under the Influence
Authors: Michelle Feng and Mason A. Porter
Abstract: Spatial networks are ubiquitous in social, geographical, physical, and biological applications. To understand the large-scale structure of networks, it is important to develop methods that allow one to directly probe the effects of space on structure and dynamics. Historically, algebraic topology has provided one framework for rigorously and quantitatively describing the global structure of a space, and recent advances in topological data analysis have given scholars a new lens for analyzing network data. In this paper, we study a variety of spatial networks—including both synthetic and natural ones—using topological methods that we developed recently for analyzing spatial systems. We demonstrate that our methods are able to capture meaningful quantities, with specifics that depend on context, in spatial networks and thereby provide useful insights into the structure of those networks. We illustrate these ideas with examples of synthetic networks and dynamics on them, street networks in cities, snowflakes, and webs that were spun by spiders under the influence of various psychotropic substances.
Saturday, September 12, 2020
Usage of the Word 'Oy'
Usage of the word 'oy' from The Joys of Yiddish: "It is uttered in as many ways as the utterer's histrionic ability permits." pic.twitter.com/Jwz5YmK5oM
— Mason Porter (@masonporter) September 13, 2020
Friday, September 11, 2020
"{Location, Location, Location}"
I am going to steal the mouseover text for other nefarious purposes: "The most important attributes of a vector in 3-space are {Location, Location, Location}"
Tuesday, September 08, 2020
RIP Paul Steen (?? – 2020)
I took a class on bifurcation theory from Paul, who was very supportive. My class project, in which I needed to use AUTO (an important aspect of the course), led to this publication.
Here is an excerpt from the Acknowledgements section:
Additionally, we express our gratitude toward Alan Champneys for several productive suggestions regarding the numerics, Alejandro Rodríguez-Luis for providing a preprint of his manuscript, and Paul Steen, whose guidance for this work as a project for ChE 753 (on which this paper is based) was particularly valuable.
Sunday, September 06, 2020
RIP Lou Brock (1939–2020)
(Tip of the cap to Gregg Schneider.)
Wednesday, September 02, 2020
RIP Tom Seaver (1944–2020)
Tuesday, September 01, 2020
UCLA's New Undergraduate Major in "Data Theory"
The video blurb about @UCLA's new undergraduate major (which I helped design) in "Data Theory" went live a week and a half ago, and I managed not to notice until now.
— Mason Porter (@masonporter) September 1, 2020
Here it is: https://t.co/iIZVPxUCK8
Update: Also see some hyperlinks in my previous blog entry about our new major.
Tuesday, August 25, 2020
"Networks of Necessity: Preventing COVID-19 Among Disabled People and Their Caregivers"
New white paper: "Networks of Necessity: Preventing COVID-19 Among Disabled People and Their Caregivers": ftp://ftp.math.ucla.edu/pub/camreport/cam20-33.pdf
— Mason Porter (@masonporter) August 25, 2020
by Michael R. Lindstrom, MAP, Hannah Shoenhard, Sarah Trick, Thomas Valles, Joseph M. Zinski
Please read and circulate. pic.twitter.com/z33lSFx8dE
Saturday, August 22, 2020
Ice Cream: Essential Ingredients for Marking Exams
On a somewhat related note, I have been known to consume ice cream when marking exams and assigning grades because it puts me in a better mood. https://t.co/adQcI2mamD
— Mason Porter (@masonporter) August 22, 2020
Thursday, August 20, 2020
August Madness
I am laughing to keep from crying. It's always been an important survival skill for me.
Also, I wish I had thought of this particular piece of snark.
(Tip of the cap to Barry Wellman.)
Sunday, August 16, 2020
Establish Dominance in Academia
Further pedagogical counsel from @ProfChrisMJones and @nlmtys.
— Carl T. Bergstrom (@CT_Bergstrom) August 16, 2020
You could be a hardass about attendance, or.... pic.twitter.com/Pa8095kmGA
"Rotating" Cubes: An Impressive Visual Illusion
One of the most powerful motion illusions I've seen: The cubes appear to be rotating in opposite directions – but they're not actually moving at all… 😮
— Steve Stewart-Williams (@SteveStuWill) August 15, 2020
Credit: @jagarikin pic.twitter.com/RgUFskZbZU
(Tip of the cap to Philip E. Tetlock.)
Friday, August 14, 2020
A Four-Base Error
It is the 1st of these that went over the wall.
(Note: The ball that went off of José Canseco's head was ruled a home run.)
Friday, August 07, 2020
Tuesday, August 04, 2020
When a Math Problem Comes Along, You Must Whip it!
When I return to teaching offline, clearly I should go full Devo. pic.twitter.com/udqmPGZ9Kw
— Mason Porter (@masonporter) August 5, 2020
Be Both the Doctor and the Kid
The Doctor.
— Jordi Lafebre (@jordilafebre) August 4, 2020
The Kid.
Be both.
🦋A new post about creativity👇:https://t.co/E7vaCJbOT2 pic.twitter.com/uKAcHMzUzX
(Tip of the cap to Sydney Padua.)
Thursday, July 30, 2020
"How to Move a SIAM Minisymposium Online from the Comfort of your Home"
Authors: Heather Z. Brooks, Yuxin Chen, Michelle Feng, Yacoub H. Kureh, Mason A. Porter, Alexandria Volkening
Thursday, July 23, 2020
Play Ball!
Given the circumstances, I'm much less excited than usual about the baseball season. But, anyway: Play ball!
Wednesday, July 22, 2020
Mookie is Here to Stay!
Monday, July 20, 2020
Cardboard "Fans" at Dodger Stadium
To make the cardboard fans at Dodger Stadium more realistic, one should only start placing them in the stands after the 3rd inning starts. ;)
— Mason Porter (@masonporter) July 21, 2020
(I write this as a die-hard, lifelong @Dodgers fan!) pic.twitter.com/t3EXkIXF2w
Sunday, July 12, 2020
"FIPO"
It is best used in verb form.
Example usage: "My paper got rejected from more than half a dozen journals and I wanted it out of my life, so I decided to FIPO it."
Friday, July 10, 2020
The Princess Bride: The Home Movie
As it turns out, this movie also includes Carl Reiner's last screen performance.
If you have seen The Princess Bride, you definitely need to watch this version.
(And if you haven't seen the original version of The Princess Bride, you have some catching up to do!)
P.S. I have the right hair for Inigo Montoya (but I think that I would make a great Dread Pirate Roberts).
Update (7/11/20): I really enjoyed this version of the movie. It is kitschy, of course, but it's supposed to be. There are some really cool performances and choices of actors in it. And some cool bits of humor with improved props. It's definitely worth watching. Obviously, it's not polished like the original, but it isn't supposed to be.
Thursday, June 18, 2020
"I Am Here to Help"
I am here to help. pic.twitter.com/JBQbTAPTQX
— Mason Porter (@masonporter) June 17, 2020
Wednesday, June 17, 2020
Congratulations to the 2020 Graduates from Our Research Group! (Humans First; Mathematicians Second)
CONGRATULATIONS to the Class of 2020 from the research group!
And thanks to Prof. Chad Topaz for a wonderful commencement speech (one of the best I ever heard and so meaningful to me). Thanks to the guests who joined us.
The graduating class of 2020:
Postdoc: Heather Zinn Brooks
Undergrads: Qinyi Chen, Unchitta Kanjanasaratool, Tony Liu
PhD students: Michelle Feng, Yacoub Kureh, William Oakley
#truecolors
Here are a couple of pictures.
And here is the text of Chad's speech.
"Are mathematicians human?"
I was very unsure of how to begin this speech, and so I did the natural thing: I Googled “graduation speech opening” and I found a site with the following advice, which I am going to obey.
1. Offer formal words recognizing the honored guests.
I hereby decree that this honored group seems familiar; have we met before?
2. Use humor. If you are confident that your humor will work, making everyone laugh will be a great start.
I am confident. Please go ahead and laugh now.
3. Enthusiastically congratulate graduates on their success.
From my heart, congratulations.
4. State the topic of your speech.
Those of you who know me know that I often go against the crowd. Some graduation speech themes are all too common, so I’ll be avoiding the following messages in this speech:
- Challenges are opportunities
- Be yourself
- The world is your oyster
- Love will triumph over all
- With great power comes great responsibility
So, for this speech, I have chosen the topic “Are mathematicians human?"
I was a postdoctoral fellow in this department from 2003 - 2006. During the last year of my postdoc, and wanting desperately to stay in academia, I applied for tenure track jobs. While I was lucky to get a couple of offers, none of the offers would have resolved my dual career couple issues. It seemed reasonable that I'd have a better chance of finding work in Los Angeles than my husband would in rural Maine. So I made one of the hardest decisions of my life: I stayed in Los Angeles and, in doing so, quit being a mathematician. But not before, in a moment of extreme frustration and angst, I committed the only physically violent act of my adult life by hurling a bowl of oatmeal at the wall of my apartment.
Sometimes we don't realize what part of our identity means until we don't have it anymore. I didn't see this coming, but when I could no longer call myself a mathematician, or at least not professionally, I wasn't sure what I was anymore.
The next year of my life began fairly miserably. I worked as a college administrator on another campus in a unit that was a poor fit for me. I had few personal goals other than feeling sorry myself. Gradually, though, things turned around. I slowly built stronger relationships with friends. I got involved in service work related to issues I cared about. I rediscovered how much I loved playing chamber works with other musicians. I reconnected with all of the parts of myself that I had let shrink.
I stopped identifying principally as a mathematician and started identifying principally as a human.
But what makes us human? Characteristics and abilities once thought to distinguish us from other animals -- the use of tools, the ability to recognize ourselves, the size of our brains, and much more -- turn out to be found in various corners of the animal kingdom. Some evidence from the natural sciences, though, does suggest what makes humans unique.
First, we are human because of the degree to which we are wired to help each other. In psychology experiments, children as young as 14 months will spontaneously help a person who is struggling or who looks worried or who drops an item. At age two years, children will help someone who isn't even aware of their own need for help, say, because they didn't realize they had dropped an item. And rewards don't seem to play a role. In experiments on 20 month old toddlers, those who had previously received rewards for being helpful acted equally helpfully as a control group that hadn't received rewards. Other species certainly have been observed to engage in helping behavior, but within different parameters. For instance, close by on the evolutionary tree, chimpanzees will share food. Chimps, however, appear to be far more selective about their helping behavior, sharing only with close relatives or potential mates. In short, humans appear to be wired to be indiscriminately cooperative.
Second, we are human because of our ability to imagine and know things beyond our senses. Take the famous psychology experiment called the Sally-Anne task. In this task, there are two dolls named Sally and Anne. A young child, who is the subject of the experiment, sees Sally putting a marble in a basket while Anne watches. Then Sally leaves the room. While she's gone, Anne removes the marble from the basket and puts it inside a box. Then Sally comes back into the room. The experimenter asks the child where Sally will look for the marble, most children answer that Sally will look in the basket, where she had originally left it. The child knows that the marble is not there, but understands that Sally will have a different thought. Let me emphasize this: it's not merely that the child knows that the marble moved. The child can put themself in the mindset of another person and imagine what that person thinks. On the other hand, in a version of the experiment designed to assess chimpanzees, the chimps generally failed the test.
So two possible answers to "what makes us human" are our level of radical, selfless cooperation and our capacity to put ourselves in the shoes of another, a quality we sometimes refer to as empathy.
This speech would not be authentic if I did not call out that we are living during challenging times. Now let's be real: epidemic disease has been with humankind for a long time, with the earliest records of an influenza-like epidemic coming from central and Southern Asia around 1200 BC. Racial injustice has been with us in the United States since before we even WERE the United States. Still, we seem to be in an especially challenging moment right now, with bungled public health efforts and the continued killing of Black people by the police. It can be hard to believe that cooperation and empathy are our nature. So I take solace in the aforementioned scientific evidence and I say thank goodness for lab experiments.
It's not just on the national and international stages that the better parts of human nature can be obscured. You will have moments in your professional and personal lives when you will have the opportunity to put your humanity second to more immediate or more tangible or just plan easier ends. My message to you today is simple: always, first and foremost, be a human.
I asked Mason to give me a few very brief words about the human qualities of each of you, graduates. Mason respected my request... except for the brevity part! So please know that when I mention each of you, the brevity is mine, not his.
Heather, you are a valued and highly respected source of wisdom.
Michelle, your creativity and passion are inspirational.
Yacoub, you are driven to help, from each individual student up to saving the world.
Will, your good cheer powers not only your own efforts, but lifts those around you.
Quinyi, you have a rare blend of determination and humility.
Unchitta, you have limitless compassion.
Tony, you fearlessly reach out to those in need.
By the way, while today is mostly about you, graduates, it is also a little bit about Mason. It doesn't escape my notice that your advisor displays stellar human qualities as well, which is perhaps why we are drawn to him.
To the seven honored and accomplished celebrants, I wish you hearty congratulations and all the best for the future. Thanks to your hard work and dedication, you are outstanding students, scholars, teachers, mathematicians, thinkers. But most of all, you are outstanding humans.
Tuesday, June 09, 2020
"Spatial Strength Centrality and the Effect of Spatial Embeddings on Network Architecture"
Title: "Spatial Strength Centrality and the Effect of Spatial Embeddings on Network Architecture"
Authors: Andrew Liu and Mason A. Porter
Abstract: For many networks, it is useful to think of their nodes as being embedded in a latent space, and such embeddings can affect the probabilities for nodes to be adjacent to each other. In this paper, we extend existing models of synthetic networks to spatial network models by first embedding nodes in Euclidean space and then modifying the models so that progressively longer edges occur with progressively smaller probabilities. We start by extending a geographical fitness model by employing Gaussian-distributed fitnesses, and we then develop spatial versions of preferential attachment and configuration models. We define a notion of “spatial strength centrality” to help characterize how strongly a spatial embedding affects network structure, and we examine spatial strength centrality on a variety of real and synthetic networks.
Sunday, June 07, 2020
The COVID-19 Graduating Class
I bought one of these for each graduating member of my research group. pic.twitter.com/H8W7Dxg2aF
— Mason Porter (@masonporter) June 7, 2020
Thursday, June 04, 2020
A Great Ph.D. Defense by Dr. Will Oakley
Congratulations to Dr. Will Oakley for a successful defense of his Ph.D. dissertation, titled "Strong Consensus-Seeking in a Model of Social Consensus Formation"! pic.twitter.com/SxCEOkMpdr
— Mason Porter (@masonporter) June 4, 2020
Tuesday, June 02, 2020
"Fitting in and Breaking Up: A Nonlinear Version of Coevolving Voter Models"
Title: Fitting in and Breaking Up: A Nonlinear Version of Coevolving Voter Models
Authors: Yacoub H. Kureh and Mason A. Porter
Abstract: We investigate a nonlinear version of coevolving voter models, in which node states and network structure update as a coupled stochastic process. Most prior work on coevolving voter models has focused on linear update rules with fixed and homogeneous rewiring and adopting probabilities. By contrast, in our nonlinear version, the probability that a node rewires or adopts is a function of how well it “fits in” with the nodes in its neighborhood. To explore this idea, we incorporate a local-survey parameter σ_i that encodes the fraction of neighbors of an updating node i that share its opinion state. In an update, with probability σ^q_i(for some nonlinearity parameter q), the updating node rewires; with complementary probability 1 − σ^q_i, the updating node adopts a new opinion state. We study this mechanism using three rewiring schemes: after an updating node deletes one of its discordant edges, it then either (1) “rewires-to-random” by choosing a new neighbor in a random process; (2) “rewires-to-same” by choosing a new neighbor in a random process from nodes that share its state; or (3) “rewires-to-none” by not rewiring at all (akin to “unfriending” on social media). We compar eour nonlinear coevolving voter model to several existing linear coevolving voter models on various network architectures. Relative to those models, we find in our model that initial network topology plays a larger role in the dynamics and that the choice of rewiring mechanism plays a smaller role. A particularly interesting feature of our model is that, under certain conditions, the opinion state that is held initially by a minority of the nodes can effectively spread to almost every node in a network if the minority nodes view themselves as the majority. In light of this observation, we relate our results to recent work on the majority illusion in social networks.
Saturday, May 30, 2020
"Nonlinearity + Networks: A 2020 Vision"
Title: Nonlinearity + Networks: A 2020 Vision
Abstract: I briefly survey several fascinating topics in networks and nonlinearity. I highlight a few methods and ideas, including several of personal interest, that I anticipate to be especially important during the next several years. These topics include temporal networks (in which a network’s entities and/or their interactions change in time), stochastic and deterministic dynamical processes on networks, adaptive networks (in which a dynamical process on a network is coupled to dynamics of network structure), and network structure and dynamics that include “higher-order” interactions (which involve three or more entities in a network). I draw examples from a variety of scenarios, including contagion dynamics, opinion models, waves, and coupled oscillators.
And in case you want to help spread the word, here is my recent tweet.
Here's the final, published version of my forward-looking chapter, "Nonlinearity + Networks: A 2020 Vision": https://t.co/eLdlD45oe8
— Mason Porter (@masonporter) May 30, 2020
It appears in the book "Emerging Frontiers in Nonlinear Science" (https://t.co/IBGX7bMyeA)
Friday, May 29, 2020
Topography Will Tear Us Apart
Unknown Topographies https://t.co/uyNZF9G7TX
— Brian Glaser (@bsglaser) May 29, 2020
(Tip of the cap to Dave Richeson.)
Thursday, May 28, 2020
An Awesome Ph.D. Defense by Dr. Yacoub Kureh!
CONGRATULATIONS to Dr. Yacoub Kureh (@Yacoub_Kureh) on a successful and very impressive defense of his PhD thesis, called "Nonlinear opinion models and other networked systems"!!! pic.twitter.com/fXDNIE1GRX
— Mason Porter (@masonporter) May 28, 2020
Tuesday, May 26, 2020
Starting Out the Hard Way
Two decades later, I am still the most opinionated TA that he's ever had with respect to how to teach a course. People should get the most difficult person out of the way at the beginning, right?
He confirmed this and found out about the ducks at our meeting this morning! It’s perfect bc he tells me that when I need a debugging break, I should talk with a rubber duck, so I think the rubber duck that is living in the tex doc right now has a permanent home 😊 (for now)
— Mallory Gaspard (@mallorygaspard) May 27, 2020
Thursday, April 30, 2020
"Community Matters"
Title: Community Matters
Authors: Anna C. F. Lewis, Nick S. Jones, Mason A. Porter, and Charlotte M. Deane
"A Framework for the Construction of Generative Models for Mesoscale Structure in Multilayer Networks"
Title: A Framework for the Construction of Generative Models for Mesoscale Structure in Multilayer Networks
Authors: Marya Bazzi, Lucas G. S. Jeub, Alex Arenas, Sam D. Howison, and Mason A. Porter
Software: You can find code for the model, as well as the outputs of the computational experiments in our paper, at this page.
Abstract: Multilayer networks allow one to represent diverse and coupled connectivity patterns—such as time-dependence, multiple subsystems, or both—that arise in many applications and which are difficult or awkward to incorporate into standard network representations. In the study of multilayer networks, it is important to investigate mesoscale (i.e., intermediate-scale) structures, such as dense sets of nodes known as communities, to discover network features that are not apparent at the microscale or the macroscale. The ill-defined nature of mesoscale structure and its ubiquity in empirical networks make it crucial to develop generative models that can produce the features that one encounters in empirical networks. Key purposes of such models include generating synthetic networks with empirical properties of interest, benchmarking mesoscale-detection methods and algorithms, and inferring structure in empirical multilayer networks. In this paper, we introduce a framework for the construction of generative models for mesoscale structures in multilayer networks. Our framework provides a standardized set of generative models, together with an associated set of principles from which they are derived, for studies of mesoscale structures in multilayer networks. It unifies and generalizes many existing models for mesoscale structures in fully ordered (e.g., temporal) and unordered (e.g., multiplex) multilayer networks. One can also use it to construct generative models for mesoscale structures in partially ordered multilayer networks (e.g., networks that are both temporal and multiplex). Our framework has the ability to produce many features of empirical multilayer networks, and it explicitly incorporates a user-specified dependency structure between layers. We discuss the parameters and properties of our framework, and we illustrate examples of its use with benchmark models for community-detection methods and algorithms in multilayer networks.
Tuesday, April 28, 2020
A Spectacular Ph.D. Thesis Defense by Michelle Feng!
CONGRATULATIONS to Dr. Michelle Feng (@michellehfeng ) on a successful — and, in fact, spectacular — defense of her Ph.D. thesis, called "Topological Tools for Understanding Complex Systems"!!!!
— Mason Porter (@masonporter) April 28, 2020
You will be hearing a lot from her in the future. pic.twitter.com/gpjueTA6CW
Monday, April 27, 2020
Short Course on "Mathematical and Computational Methods for Complex Social Systems" at the 2021 Joint Mathematics Meetings!
An exciting announcement!
— Mason Porter (@masonporter) April 28, 2020
We (@hzinnbrooks + @michellehfeng + Me + @al_volkening) are organizing an @amermathsoc 'Short Course' on "Mathematical and Computational Methods for Complex Social Systems" at the 2021 Joint Mathematics Meetings (@JointMath)! https://t.co/A4rXWVOWSU pic.twitter.com/e9hTEDLCN4
Sunday, April 26, 2020
"And Then the Dragons Arrived."
Let's try this with my own book: "Traditionally, much of the study of networks has focused on structural features. And then the dragons arrived."
— Mason Porter (@masonporter) April 27, 2020
You know, that kind of works. I want to write this book!
This is the book (coauthored with @gleesonj): https://t.co/PtNjiV7voB https://t.co/lZevcObzYt
Saturday, April 25, 2020
Dramatic Readings of Academic Research and Other Scholarly Works
I am doing "dramatic readings" of scholarly research as part of a series of short podcasts for the Annals of Improbable Research (@improbresearch).
— Mason Porter (@masonporter) April 25, 2020
A new one dropped today ("Mask Wiggling"): https://t.co/I9zhPODp1H
Another one ("Cocker’s Arithmetick"): https://t.co/66twU8zjqn
Monday, April 20, 2020
A Paper Called "Lunch Menu" on Google Scholar
"Lunch Menu" by T. B. Dishes and P. Kids also exists, cited 14 times https://t.co/8RR1rvYfKs
— Hiroki Sayama (@HirokiSayama) April 21, 2020
Tuesday, April 14, 2020
"A Model for the Influence of Media on the Ideology of Content in Online Social Networks"
Title: A Model for the Influence of Media on the Ideology of Content in Online Social Networks
Authors: Heather Z. Brooks and Mason A. Porter
Abstract: Many people rely on online social networks as sources of news and information, and the spread of media content with ideologies across the political spectrum influences online discussions and impacts offline actions. To examine the impact of media in online social networks, we generalize bounded-confidence models of opinion dynamics by incorporating media accounts as influencers in a network. We quantify partisanship of content with a continuous parameter on an interval, and we formulate higher-dimensional generalizations to incorporate content quality and increasingly nuanced political positions. We simulate our model with one and two ideological dimensions, and we use the results of our simulations to quantify the “entrainment” of content from nonmedia accounts to the ideologies of media accounts in a network. We maximize media impact in a social network by tuning the number of media accounts and the numbers of followers of those accounts. Using numerical computations, we find that the entrainment of the ideology of content that is spread by nonmedia accounts to media ideology depends on a network's structural features, including its size, the mean number of followers of its nodes, and the receptiveness of its nodes to different opinions. We then introduce content quality—a key novel contribution of our work—into our model. We incorporate multiple media sources with ideological biases and quality-level estimates that we draw from real media sources and demonstrate that our model can produce distinct communities (“echo chambers”) that are polarized in both ideology and quality. Our model provides a step toward understanding content quality and ideology in spreading dynamics, with ramifications for how to mitigate the spread of undesired content and promote the spread of desired content.
Friday, April 10, 2020
Los Angeles Without Smog
Los Angeles with no smog..
— Bill Gross (@Bill_Gross) April 10, 2020
Aerial view of downtown from Silverlake via @alanwdang pic.twitter.com/qOxAAzDzmX
(Tip of the cap to Predrag Cvitanovic.)
Sunday, March 29, 2020
RIP Philip Anderson (1923–2020)
I can't yet find an obituary to include as a hyperlink.
Update (3/30/20): The New York Times has published an obituary.
Update (3/30/20): Here is an obituary from Princeton University.
Saturday, March 28, 2020
RIP Nate 'n Al Delicatessen (1945–2020)
I have been getting food from there for more than 40 years, and it has my favorite corned-beef sandwiches.
Well, I guess I ordered my last two corned beef sandwiches from them last night. :( I got it delivered. (I'll nuke the second one for dinner today or tomorrow.)
I was going to eat dinner there with some of my students on 14 March, but I necessarily cancelled that dinner. Some of them have tried it before, and I have now informed the one who mentioned last night that she might try it that today is the day for her if it's ever going to happen.
I'll share a different one of my childhood restaurants with my students. (The Apple Pan is a difficult choice when things get back to normal, though, given the way that seating works there.)
Update (3/29/20): Nate 'n Al's isn't quite dead yet. Hopefully, they'll make it through this crisis and come back around when we get past it.
Friday, March 20, 2020
Cooking: Yet Another Sign of the Apocalypse
And, well, here we are.
(The picture above is the first in a sequence of five pictures. I ate those noodles out of sheer stubbornness.)
Another Sign of the Apocalypse: Oxford has Cancelled its Conventional Exams
Thankfully, Coffee is an Essential Service.
Time has no Meaning.
Also, space has no meaning.
Also, spacetime has no meaning.
(In addition to the fact that now I end up using the same technology to talk to somebody who is 1 mile away as somebody who is on the other side of the world, and that I can be anywhere in the world when I teach my courses online — which is inspiring these "delightful" thoughts — I naturally thought of a line from this sketch. One of my friends has subsequently reminded me of the quote "Time is an illusion. Lunchtime, doubly so.")
My mood is also captured by this video.
It's (Probably Not) the End of the World as we Know it (and I Feel Fine)
(Tip of the cap to the Improbable Research blog.)
Tuesday, March 17, 2020
A Real-World Devilish Wish
It is very strange to wake up in that kind of world. Most people are trying their best to do more extreme forms of many of the things that I try to do anyway in my normal life.
This is the type of thing that I would do as a Dungeon Master to a wish-maker who didn't phrase their wish very carefully.
Monday, March 16, 2020
Way Ahead of My Time
I was way ahead of my time.
Saturday, March 14, 2020
A Song for Today's Era of Social Distancing
Second: I am proud that one of my PhD students brought up this song in his e-mail just now. Between that and the fact that another of my PhD students has The Princess Bride as one of her favorite movies.
(In case you needed even more evidence that I have awesome students...)
Preparing to Teach Classes in Cyberspace
In preparation for online lecturing, I am practicing using Zoom with my cousin.
— Mason Porter (@masonporter) March 14, 2020
There appears to be a time lag. pic.twitter.com/GgRI95tku9
Friday, March 13, 2020
Behind-the-Scenes Pictures of Professors Suddenly Transitioning to Online Teaching
I am greatly looking forward to behind-the-scenes pix of profs improvising while abruptly transitioning to remote teaching. https://t.co/Lww5ZHzfY5
— Mika McKinnon (@mikamckinnon) March 13, 2020
A Sign of the End of Days
Now we know that we've reached the end of days.
(That said, they were faster than UCLA for blanket approval.)
Thursday, March 12, 2020
The Major League Baseball Season is Delayed
This is perhaps the first time in my life that I have ever been strongly in favor of baseball being cancelled. Simply, it's the right thing to do.
Baseball is one of my coping mechanisms, but I will find others.
Glora Gayner Demonstrating Thorough Hand-Washing by Singing "I Will Survive"
Tuesday, March 10, 2020
My Personalized Pandemic Card
Here is my personalized Pandemic card. pic.twitter.com/WRnyw60clU
— Mason Porter (@masonporter) March 10, 2020
In case you're interested, you can find templates on this website.
Friday, March 06, 2020
"Dominance, Sharing, and Assessment in an Iterated Hawk–Dove Game"
(I write this even though they pulled the trigger without showing us the final version — despite our explicit request — and a couple of minor glitches with the references reflect this. Following instructions was consistently very difficult for these typesetters.)
Anyway, I really like this paper, and I think there are some very cool avenues to pursue with it as a starting point. Our public code will hopefully help encourage such efforts. Here are some details.
Title: Dominance, Sharing, and Assessment in an Iterated Hawk–Dove Game
Authors: Cameron L. Hall, Mason A. Porter, and Marian S. Dawkins
Abstract: Animals use a wide variety of strategies to reduce or avoid aggression in conflicts over resources. These strategies range from sharing resources without outward signs of conflict to the development of dominance hierarchies, in which initial fighting is followed by the submission of subordinates. Although models have been developed to analyse specific strategies for resolving conflicts over resources, little work has focused on trying to understand why particular strategies are more likely to arise in certain situations. In this paper, we use a model based on an iterated Hawk–Dove game to analyse how resource holding potentials (RHPs) and other factors affect whether sharing, dominance relationships, or other behaviours are evolutionarily stable. We find through extensive numerical simulations that sharing is stable only when the cost of fighting is low and the animals in a contest have similar RHPs, whereas dominance relationships are stable in most other situations. We also explore what happens when animals are unable to assess each other’s RHPs without fighting, and we compare a range of strategies for contestants using simulations. We find (1) that the most successful strategies involve a limited period of assessment followed by a stable relationship in which fights are avoided and (2) that the duration of assessment depends both on the costliness of fighting and on the difference between the animals’ RHPs. Along with our direct work on modelling and simulations, we develop extensive software to facilitate further testing. It is available at https://bitbucket.org/CameronLHall/dominancesharingassessmentmatlab/.
A Physical Hand-Washing Mnemonic
An easy way to remember hand-washing procedure. pic.twitter.com/zjwnEZIq5D
— Chris Ferrie (@csferrie) March 5, 2020
(Tip of the cap to Eva Miranda.)
Wednesday, March 04, 2020
A Great 'Team' Page
Take a look at it for the short video clips!
(Tip of the cap to Carl Bergstrom.)
Sunday, March 01, 2020
Attention, Reuters: Proper Use of Colons is Important
Gosh, I hope the governor recovers soon. 🙄
— Dr. Jonathan Foley (@GlobalEcoGuy) March 2, 2020
(Reuters needs to make sure everyone on staff takes an English class.) https://t.co/Kh6KtDlUej
(Tip of the cap to Calling Bullshit.)
Update: Well, from the link (below) that Gregg Schneider just sent me, it appears that Reuters may have a writer who does not understand how to use colons properly.
Just one American with coronavirus still in hospital: Vice President Pence https://t.co/0aM9djXlEx pic.twitter.com/Zha44JLUmb
— Reuters (@Reuters) February 28, 2020
Friday, February 28, 2020
An Otter's "Careless Whisper"
For the love of god UNMUTE THIS pic.twitter.com/MA48mit8MX
— Nerd Girl Says (@Rachael_Conrad) February 23, 2020
(Tip of the cap to Card Colm Mulcahy.)
Monday, February 24, 2020
"Automatic Generation of School Bus Routes in Los Angeles"
Title: Automatic Generation of School Bus Routes in Los Angeles
Authors: Mason A. Porter, David J. Spender, and Cu Hauw ("Willy") Hung
Abstract: The goal of our project is to automatically generate school bus routes for the Los Angeles Unified School District (LAUSD). We examined four algorithms, including two from the existing literature and two new ones that we developed. A major focus of our work was the construction of “mixed-load routes,” which transport students from multiple schools. Based on our measurements (whose imperfections we discuss), three of the four algorithms perform at least as well as the existing route plan, and one of those three performs better than the existing route plan. We also delivered a user-friendly routing program to LAUSD that uses one of these algorithms, and we have made our software publicly available. Our insights and results are also applicable to other school districts that permit mixed-load routing.
Sunday, February 23, 2020
A Comic-Book Café in Korea
I want to go and hang out in this café.
(And I want to play "Take On Me" as background music while I am there.)
Saturday, February 22, 2020
Remote Login: "A Lot Like Astral Projection"
— Science Diagrams that Look Like Shitposts (@scienceshitpost) January 26, 2020
(Tip of the cap to Charles W. Clark.)
Sunday, February 16, 2020
Stay Tuned for My Mathematics Opinion Piece :)
Achievement Unlocked: I'm pretty sure that this is the first time I've felt the need to promise to an editor that I would not swear in an opinion piece that I'm going to write about mathematics.
— Mason Porter (@masonporter) February 17, 2020
Note: You should have seen the smile on my face when I was asked to write this. :P
In case you're wondering, the correct analogy (which you'll understand if you are familiar with Dragonlance) is "Tasslehoff was bored." (Nothing on Krynn is more dangerous than a bored kender.)
A sudden thought: I wonder if this counts as an Invited Tirade?
Saturday, February 15, 2020
"Contributed Tirades"
My contribution is "Contributed Tirades". I wonder if I have ever had any Invited Tirades?
Thanks to Dan Larremore for the inspiration!
Tuesday, February 04, 2020
Dodgers Acquire Mookie Betts (and David Price)!
Wow!
Update: And right after the big trade above, the Dodgers traded Joc Pederson to the Los Angeles Angels for infielder Luis Rengifo.
Update (2/09/20): After the original version of the trade hit a snag (because of a medical test on Brusdar Graterol), the Dodgers, Red Sox, and Twins have now officially agreed on a trade (so it's now a done deal). Our trades with the Red Sox and Twins are now two separate deals, and a couple of other Dodger prospects (shortstop Jeter Downs and catcher Connor Wong) are now also going to the Red Sox.
Update (2/09/20): The Dodgers also get another prospect and a draft pick from the Twins, and (according to David Schoenfield) the trade of Joc Pederson to the Angels (which apparently was contingent on the trade for Betts) appears to be a casualty of the delay in finalizing the trade for Betts.
Monday, February 03, 2020
"Online Reactions to the 2017 ‘Unite the Right’ Rally in Charlottesville: Measuring Polarization in Twitter Networks Using Media Followership"
Title: Online Reactions to the 2017 ‘Unite the Right’ Rally in Charlottesville: Measuring Polarization in Twitter Networks Using Media Followership
Authors: Joseph H. Tien, Marisa C. Eisenberg, Sarah T. Cherng, and Mason A. Porter
Abstract: Network analysis of social media provides an important new lens on politics, communication, and their interactions. This lens is particularly prominent in fast-moving events, such as conversations and action in political rallies and the use of social media by extremist groups to spread their message. We study the Twitter conversation following the August 2017 ‘Unite the Right’ rally in Charlottesville, Virginia, USA using tools from network analysis and data science. We use media followership on Twitter and principal component analysis (PCA) to compute a ‘Left’/‘Right’ media score on a one-dimensional axis to characterize Twitter accounts. We then use these scores, in concert with retweet relationships, to examine the structure of a retweet network of approximately 300,000 accounts that communicated with the #Charlottesville hashtag. The retweet network is sharply polarized, with an assortativity coefficient of 0.8 with respect to the sign of the media PCA score. Community detection using two approaches, a Louvain method and InfoMap, yields communities that tend to be homogeneous in terms of Left/Right node composition. We also examine centrality measures and find that hyperlink-induced topic search (HITS) identifies many more hubs on the Left than on the Right. When comparing tweet content, we find that tweets about ‘Trump’ were widespread in both the Left and Right, although the accompanying language (i.e., critical on the Left, but supportive on the Right) was unsurprisingly different. Nodes with large degrees in communities on the Left include accounts that are associated with disparate areas, including activism, business, arts and entertainment, media, and politics. By contrast, support of Donald Trump was a common thread among the Right communities, connecting communities with accounts that reference white-supremacist hate symbols, communities with influential personalities in the alt-right, and the largest Right community (which includes the Twitter account FoxNews).
Note: And only now after several rounds of page proofs, right after it's too late, do I notice that the typesetters changed "Right" to "right" in the paper title, even though it is a proper noun. Well, we had plenty of chances to notice this typo that they introduced, so it's frustrating that this is another one of those that I notice immediately as soon as it's published (while not catching it in my numerous chances to see it).
Tuesday, January 28, 2020
Boycotting a Coin Over a "Missing" Oxford Comma
(Tip of the cap to Sam Howison.)
Monday, January 27, 2020
"Quantifying “Political Islands” with Persistent Homology"
I finally get to share my new @TheSIAMNews article (by @michellehfeng and me): "Quantifying “Political Islands” with Persistent Homology"https://t.co/ocpZN43EHg
— Mason Porter (@masonporter) January 28, 2020
You may also be interested in our associated research article and our recent follow-up article.
Saturday, January 25, 2020
New 2020 Baseball Hall of Famers
Anyway, the new Major League Baseball Hall of Famers that were just elected by the writers are Derek Jeter (in his first year of eligibility) and Larry Walker (in his 10th and final year on the writers' ballot). I'm really pleased that Larry Walker was voted in by the writers! He should have made it years ago, but thankfully he made huge gains in each of the last three years (and especially in each of the last two years). For Jeter, the only question was whether he'd be unanimous; one person left him off of their ballot. Jeter and Walker join Ted Simmons and Marvin Miller as 2020's inductees into the Hall of Fame.
This year's vote totals are available at this website, and you can also take a look at the Hall of Fame Voter Tracker, which I was following assiduously in the weeks leading up to the announcement of the new inductees.
Scott Rolen was polling at close to 50% before the results were announced. He gained a ton of votes, but after seeing where he was before the announcement, I was a bit surprised to see the final total at "only" about 35%. Todd Helton made major gains to almost 30%, perhaps because he's no longer on his first ballot. They're in good shape, but it will take a while.
Curt Schilling got to 70%, so he'll make it in 2021. Nobody who has a shot is debuting on the ballot next year (well, maybe Tim Hudson will make it eventually), so 2021 is Schilling's year.
Rogers Clemens and Barry Bonds crept over 60%. I'll be very surprised if the writers elect them, as people have drawn lines in the sand, but one of the current incarnations of the Veterans Committees will put them in the Hall someday.
Omar Vizquel (sigh) broke the 50% barrier, and his eventual election is inevitable.
Billy Wagner, Gary Sheffield, and Andruw Jones made big gains. (I wonder if the latter two were helped not only by there being only one obvious newcomer but also by Harold Baines now being in the Hall? Both Jones and Sheffield were much better players than Baines.) We'll see how much Wagner gains over the next years.
Jeff Kent also made major inroads, and he'll likely make it eventually via one of the Veterans Committees.
A bunch of others (such as Manny Ramirez and Sammy Sosa) also gained a decent amount, but I doubt they'll go much of anywhere on the regular ballot (and Sosa has achieved around this many votes in some past years as well, I believe).
Bobby Abreu managed to get just enough votes to stay on the ballot next year. That's good.
And the latest entries in the exactly-one-vote club are Adam Dunn, Brad Penny, Raúl Ibañez, and J. J. Putz (who once hit Kevin Mench with a pitch, marking the only time in Major League Baseball history that a Mench got hit by a Putz).
There aren't any Hall-of-Fame-caliber standouts debuting on the 2021 ballot, so perhaps it will only be Curt Schilling from the regular ballot next year.
David Schoenfield wrote about this year's winners and losers in the Hall of Fame voting.
Here is my blog entry about the result of last year's writers' votes.