Past Meetup

PWL#19 => Jason Brown on Epidemic Algorithms for Replicated Database Maintenance

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PWL Mini

Stephen Tu ( presents: "Random features for large-scale kernel machines" ( ) by Ali Rahimi and Ben Recht

Kernel methods in machine learning are a popular tool used to express richer function classes. These methods work via access to a kernel function, which can be thought of as a measure of similarity between two vectors. The standard method of optimization via kernels requires solving a program with decision variable the size of the number of data points. As dataset sizes grow, this becomes prohibitive.

This paper addresses this issue in a surprisingly practical way. Specifically, the authors show that by using a multiple of d random projections based on the Fourier transform of the kernel function (where d is the ambient dimension), one can accurately approximate the kernel function. This allows practitioners to use fast linear solvers and retain the benefits of more expressive function classes.

Stephen ( is a graduate student in EECS at UC Berkeley.

Main talk

Jason Brown ( on the Epidemic Algorithms for Replicated Database Maintenance paper (

From Jason: "While published in 1987, 'Epidemic Algorithms for Replicated Database Maintenance' describes an early distributed system that uses gossip replication and eventual consistency (the latter uncannily like modern NoSQL databases).

The subject of gossip branched into some interesting directions since the '80s, I'll primarily concentrate on the Demers paper, give a brief survey of the gossip literature, and tie those papers into some modern, well-known systems (namely, Cassandra and Riak)."

Jason Brown ( is a Senior Software Engineer at Apple, as well as being an Apache Cassandra Committer. He holds a Master’s degree in Music Composition is searching for time to write a second string quartet.

Meeting mechanics

Doors open at 6:30 pm; the presentation will begin at 7:00 pm; and, yes, there will be food.

After the paper is presented, we will open up the floor for discussion and questions.