blog @ johnemmons.com

A no-frills blog about my life and work as a PhD student



AWSLambdaFace: serverless face recognition
April 26, 2017
TL;DR: Serverless compute platforms such as Amazon Web Services (AWS) Lambda were intended to be used for web microservices and to handle asynchronous events generated by other Amazon web services (DynamoDB, S3, SNS, etc.). However, AWS Lambda also allows users to upload arbitrary linux binaries along with their lambda functions. These binaries can be executed during a lambda invocation, effectively turning AWS Lambda into a supercomputer that can be started on-demand in seconds and billed at a 100ms granularity. In this post, I will show you how I deployed a full-blown deep convolutional neural network based face recognition tool on AWS Lambda and used the system to query for faces in videos in a massively parallel way (skip to figure 2 to see the end result!). Read more...

RAID in the Wild
April 23, 2017
TL;DR: Redundant array of independent disks (RAID) is an old technology (first conceived in 1977) for improving the reliability, availability, and performance of disk drives. You likely interact with systems that use RAID on a daily basis as it backs almost all storage systems and is used in applications ranging from commercial cloud storage to supercomputing. However for me (and probably many others), RAID was only ever a clever idea discussed on the chalkboard for ~10 minutes in a college computer systems course. Well, I just experienced a disk failure on my personal file server and the RAID1 setup I had saved the day (no data loss!); even though this is not remarkable from a theoretical standpoint, there is something satisfying about seeing this classroom concept work in the wild. Read more...

First Day as a PhD Student at Stanford
September 26, 2016
TL;DR: I have worked in worked in eight different research groups across five universities since I started performing research my first semester of undergrad. As far as understanding what it means to be a grad student (specifically a PhD student) in the sciences, I am more informed than just about anyone my age. I have seen both the good and the bad parts (especially the bad parts) of academia first hand; and in my opinion, anybody that is not absolutely sure they want a PhD (or has a halfway decent alternative) that chooses to attend graduate school is almost certainly an idiot. Read more...

Last updated: June 17, 2017