Alexander Wei, Author at Alexander Wei, B.A. M.S.

Solution Space Techniques for Faster Convergence, an introduction

Many strategies in Machine Learning involve the iterative search of a solution space Ω. We begin with an initial solution ω₀ and update ωₙ to minimize an objective function f(x)

Solve a Substitution Cipher with a Markov chain

Photo by Mauro Sbicego on Unsplash

There are k! substitution ciphers for an alphabet with k letters—too many for an exhaustive search. With a frequency-based approach adapted to the graph of alphabetic ciphers, we redefine the act of deciphering as a sampling problem suitable for a Metropolis-Hastings random walk. A substitution cipher is thus solvable with a Markov chain. Let’s begin… Continue reading Solve a Substitution Cipher with a Markov chain

Plant Pairs on the Tufts Campus

Photo by Markus Spiske on Unsplash

In Spring of 2019 my Environmental Fieldwork class surveilled the herbaceous plants growing on and around the Tufts campus, recording their identities and locations into a GIS database. For a final project I created a simple Cartesian quadrature algorithm in Python to identify the distinct plant pairs most likely to share the same soil. Whether… Continue reading Plant Pairs on the Tufts Campus