Friday, December 31, 2021

RIP Betty White (1922–2021)

Iconic actress Betty White died today at age 99. January 17 was going to be her 100th birthday. You can read a lot about her on her Wikipedia page.

Thursday, December 30, 2021

"Epidemic Thresholds of Infectious Diseases on Tie-Decay Networks"

Another paper of mine has just been published in final form. (Technically, one could say that it's almost in final form; the issue number has been determined, but its stamp is not yet on the .pdf file as I write this blog entry because some other articles from the same issue haven't yet been published.) Here are some details.

Title: "Epidemic Thresholds of Infectious Diseases on Tie-Decay Networks"

Authors: Qinyi Chen and Mason A. Porter

Abstract: In the study of infectious diseases on networks, researchers calculate epidemic thresholds to help forecast whether or not a disease will eventually infect a large fraction of a population. Because network structure typically changes with time, which fundamentally influences the dynamics of spreading processes and in turn affects epidemic thresholds for disease propagation, it is important to examine epidemic thresholds in models of disease spread on temporal networks. Most existing studies of epidemic thresholds in temporal networks have focused on models in discrete time, but most real-world networked systems evolve continuously with time. In our work, we encode the continuous time-dependence of networks in the evaluation of the epidemic threshold of a susceptible–infected–susceptible (SIS) process by studying an SIS model on tie-decay networks. We derive the epidemic-threshold condition of this model, and we perform numerical experiments to verify it. We also examine how different factors—the decay coefficients of the tie strengths in a network, the frequency of the interactions between the nodes in the network, and the sparsity of the underlying social network on which interactions occur—lead to decreases or increases of the critical values of the threshold and hence contribute to facilitating or impeding the spread of a disease. We thereby demonstrate how the features of tie-decay networks alter the outcome of disease spread.

Thursday, December 23, 2021

"Classical and Quantum Random-Walk Centrality Measures in Multilayer Networks"

Another paper of mine just came out in final form. Here are some details about it.

Title: Classical and Quantum Random-Walk Centrality Measures in Multilayer Networks

Authors: Lucas Böttcher and Mason A. Porter

Abstract: Multilayer network analysis is a useful approach for studying networks of entities that interact with each other via multiple relationships. Classifying the importance of nodes and node-layer tuples is an important aspect of the study of multilayer networks. To do this, it is common to calculate various centrality measures, which allow one to rank nodes and node-layers according to a variety of structural features. In this paper, we formulate occupation, PageRank, betweenness, and closeness centralities in terms of node-occupation properties of different types of continuous-time classical and quantum random walks on multilayer networks. We apply our framework to a variety of synthetic and real-world multilayer networks, and we identify notable differences between classical and quantum centrality measures. Our computations give insights into the correlations between certain centralities that are based on random walks and associated centralities that are based on geodesic paths.

Tuesday, December 14, 2021

"Motifs for Processes on Networks"

Another paper of mine has just been published in final form. Here are some details.

Title: "Motifs for Processes on Networks"

Authors: Alice C. Schwarze and Mason A. Porter

Abstract: The study of motifs can help researchers uncover links between the structure and function of networks in biology, sociology, economics, and many other areas. Empirical studies of networks have identified feedback loops, feedforward loops, and several other small structures as "motifs" that occur frequently in real-world networks and may contribute by various mechanisms to important functions in these systems. However, these mechanisms are unknown for many of these motifs. We propose to distinguish between "structure motifs" (i.e., weakly connected graphlets) in networks and "process motifs" (which we define as structured sets of walks) on networks and consider process motifs as building blocks of processes on networks. Using steady-state covariance and steady-state correlation in a multivariate Ornstein--Uhlenbeck process on a network as examples, we demonstrate that distinguishing between structure motifs and process motifs makes it possible to gain quantitative insights into mechanisms that contribute to important functions of dynamical systems on networks.

Friday, December 10, 2021

"Finding Your Way: Shortest Paths on Networks"

Another article of mine just came out in final form. Here are some details.

Title: Finding Your Way: Shortest Paths on Networks

Authors: Teresa Rexin and Mason A. Porter

Abstract: Traveling to different destinations is a major part of our lives. We visit a variety of locations both during our daily lives and when we are on vacation. How can we find the best way to navigate from one place to another? Perhaps we can test all of the different ways of traveling between two places, but another method is to use mathematics and computation to find a shortest path between them. In this article, we discuss how to construct shortest paths and introduce Dijkstra’s algorithm to minimize the total cost of a path, where the cost may be the travel distance, the travel time, or some other quantity. We also discuss how to use shortest paths in the real world to save time and increase traveling efficiency.

Tuesday, December 07, 2021

Sunday, December 05, 2021

New Hall of Famers from Two of the Era Committees

We have some new Hall of Famers!

The Golden Days Era Committee has elected Tony Oliva, Jim Kaat, Minnie Miñoso, and Gil Hodges to the Hall of Fame. I'm glad that Oliva, Hodges, and (especially) Miñoso are finally in the Hall of Fame. However, Jim Kaat should not have made it, and fellow Golden Era candidate Dick Allen bloody well should be in the Hall of Fame. Take a look at this series of articles for discussions of each of the candidates.

The Early Baseball Era Committee has elected Bud Fowler and Buck O'Neil to the Hall of Fame. Take a look at this series of articles for discussions of each of the candidates.

You can track the regular Hall of Fame ballotting on the usual ballot tracker. I am guessing that they're going to throw a shutout for the second year in a row, but players such as Todd Helton and Scott Rolen (and some others) should make good progress towards eventual election.

Update (12/06/21): As discussed in this article, Dick Allen fell one vote short for the second time in a row. :( Maybe next time, although even then he is no longer alive to enjoy it.

Wednesday, December 01, 2021

What Happens in Salt Lake City Stays in Salt Lake City

I am heading off to Salt Lake City to give a talk at University of Utah!