Sam Zhang

The illusion of predictability in common scientific visualizations

Even experts think / that well-estimated means / are certain outcomes. (Haiku summary due to MSR poets Dan and Jake). Click the thumbnail for a mini-explainer.

The illusion of predictability in common scientific visualizations

Sam Zhang, Patrick R Heck, Michelle Meyer, Christopher F Chabris, Daniel G Goldstein, Jake M Hofman socRxiv, 2022 [paper]

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Elliptic curves and traveling wave solutions to the KdV equations

View traveling wave solutions to the KdV equations associated with (points of) elliptic curves.

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Ridge unfolding polytopes

Unfold 4-dimensional polytopes using their spanning trees. Joint work with Matt Harvey and Satyan Devadoss.

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Bayesian inference for COVID-19 testing

My brief foray into epidemiology at the start of COVID-19. Bayesian methods and interactive tools for informing COVID-19 surveillance testing strategies.

Estimating SARS-CoV-2 seroprevalence and epidemiological parameters with uncertainty from serological surveys

Daniel B Larremore, Bailey K Fosdick, Kate M Bubar, Sam Zhang, Stephen M Kissler, C Jessica E Metcalf, Caroline O Buckee, Yonatan H Grad eLife, 2021 [paper]

Jointly modeling prevalence, sensitivity and specificity for optimal sample allocation

Daniel B Larremore, Bailey K Fosdick, Sam Zhang, Yonatan H Grad bioRxiv, 2020 [paper]

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Curve shortening

Deform a curve with a discrete curve shortening flow.

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A catastrophe machine

Move the center of gravity of a wedge balancing on a table, and observe its corresponding catastrophe surface.

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Linear regression, the old fashioned way

Perform ordinary least squares through a set of points with nails, springs, sleeves, and a frictionless rod.

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A moduli space for triangles

A solution to a problem by Lewis Carroll using a clever moduli space. For fun, pick points on the moduli space, and watch triangles deform between them along geodesics.

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The cross-section of a cylinder is an ellipse

A classical proof that the cross-section of a cylinder is an ellipse. I have no idea why, but this is the most popular blog post on my website.

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Whitney's Umbrella

First steps in visualizing 3d mathematics using javascript. A famous surface with a cuspidal point.

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Voronoizer bookmarklet

Draw a Voronoi diagram over any webpage with this bookmarklet.

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Voronoize this page!

This page has a Voronoi diagram drawn over it, with link and input HTML elements as points.

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Treasure hunting

You have been given flawed instructions for finding treasure on an island, but geometry may be able to help.

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An ascii implicit function plotter

Plot an elliptic curve (or any implicit function) using ASCII art!

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Hypocycloids

What happens if you rotate a smaller circle inside of a larger circle?

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Cats on ladders

A cat is sitting on a ladder leaning against the wall, and the ladder slips. What shape does the cat draw through the air?

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A network look at integer sequences

The Online Encyclopedia of Integer Sequences (OEIS) from a 10,000 foot view.

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A visualization of a geometric bound on convex hulls

A lemma that bounds the size of a convex hull of points based off circles centered at those points.

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Building a municipal land use code search engine using a graph of word embeddings

Using the geometry of language to help permit-seekers find the right municipal land use codes.

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