Work & writings | John Wang

Here’s some of the work that I’ve written or been a part of writing:

Rain-induced Ejection of Pathogens from Leaves. I worked under Lydia Bourouiba and Tristan Gilet to study how diseases spread across plants during rainfall. Previously, scientists believed that raindrops would fall onto a thin film of water on a leaf, splashing pathogens to other plants. We showed that a more likely mechanism was a slingshot-like flinging of water droplets when rain hits a leaf. We also developed math models to characterize this behavior.
The Chaotic Dynamics of Aquatic Interactions. This paper studied limit cycles and interactions of different aquatic creatures. I love this paper because it demonstrates how seemingly simple equations can lead to the intricate dynamical systems characteristic of Chaos Theory.

The Rise and Fall of American Growth. I was a research assistant for Robert J. Gordon’s book focusing on the quality of American housing between 1870 and 1940 (Chapter 4). This period saw massive improvements in quality of life from indoor plumbing, appliances, and especially electricity.
School Structure and Academic Achievement. Michael Mirski and I spent a few years studying the black white achievement gap under Emily Oster and Kerwin Charles. We showed that placing 6th graders into middle schools hurt academic achievement, especially black students.
Security on Networks. I worked with Bonny Jain and Iris Xu to investigate infection spread across random graphs and the effectiveness of network security at preventing infection spread.

Quickselect. A Golang library to find the smallest k elements in a set. I originally wrote this for Assembled, but open sourced it because of the lack of selection algorithm libraries in Golang. Quickselect uses Hoare’s Selection Algorithm which is asymptotically optimal, but switches to a naive algorithm for small sets to optimize speed.
Creditly. A credit card input form, written before the days when Stripe Elements and other credit card processing forms became ubiquitous and easily available.
Wallace. A framework for training machine learning models with evolutionary algorithms. It takes in a dataset and determines the best machine learning model and parameters to use using differential evolution. It’s named after Alfred Russel Wallace, someone who never got any credit for his work on natural selection and evolution.
EagerDB. A database management tool that predictively preloads queries and warms your SQL cache. Here’s the paper describing how it works.

Course notes from MIT. In college, I took notes primarily in LaTeX, which means I’ve been able to accumulate a ton of interesting knowledge in digital form.
How Garbage collection in Python works. I read the CPython garbage collection code and wrote a Quora post about it.
Python implementation of perfect hashing. When I was learning to code, I would take algorithms that I learned in class and convert them into code. This is one of my favorites.