About Me

I am a passionate machine learning engineering leader empowering high performing teams to deliver measurable results with AI/ML. I instill engineering excellence into my team for high velocity delivery of solutions aligned with business goals. I have expertise in leadership, motivation, recommender systems, software engineering best practices, and kubernetes. I currently work for Paramount Streaming in the Applied Machine Learning Group improving personalization across services including Paramount+ and Pluto TV.

News

Aug 2022	I was promoted to Director of Machine Learning Engineering and Personalization in the Applied Machine Learning Group within Paramount Global Streaming
Jan 2021	I was promoted to Principal Machine Learning Engineer in the Applied Machine Learning Group within ViacomCBS Streaming
Mar 2020	I will be presenting "Deploying Machine Learning Models with Flask and Docker" at PyTennessee 2020
Oct 2019	I attended ODSC West 2019 in San Francisco, California
Apr 2019	I was promoted to Lead Machine Learning Engineer in the Applied Machine Learning Group within CBS Interactive
Apr 2019	I presented "A Glimpse into CBS Interactive's AI/ML Group" at Google Next 2019 in San Francisco, California Available on YouTube
Aug 2018	I presented "Serverless Streaming Web Analytics with AWS Kinesis and Lambda" at the Nashville Analytics Summit and Nashville AWS users group meetup
Jul 2018	I was promoted to Senior Machine Learning Engineer in the Applied Machine Learning Group within CBS Interactive.
Mar 2018	I presented "Building a Serverless Recommendation Engine" at the Brentwood Artificial Intelligence meetup discussing how to use AWS Lambda and PySpark on AWS ElasticMapReduce using collaborative filtering to generate personalized recommendations for millions of users for just a few dollars.
Feb 2018	I attended PyTennessee 2018 in Nashville, Tennessee
Nov 2017	I attended AWS re:Invent 2017 in Las Vegas, Nevada
Jul 2017	I presented my work integrating our custom analytics with Splunk into our chatbot for on-demand analytics queries by our publishers at the Splunk Nashville Users Group.
Apr 2017	I began work as a Data Engineer at 247Sports.com within CBS Interactive
Mar 2017	I successfully defended my PhD in Electrical Engineering from Vanderbilt Univeristy entitled "Optic Nerve Characterization using Magnetic Resonance Imaging: The Search for Biomarkers" under the supervision of Dr. Bennett Landman (Electrical Engineering) and Dr. Seth Smith (Radiology and Biomedical Engineering).
Feb 2017	I attended SPIE Medical Imaging in Orlando, FL

Work Experience

Aug 2022 - Present	Paramount Global Streaming - Applied ML Group, Director, Machine Learning Engineering and Personalization
Lead a team of seven MLEs to develop and deploy production-quality machine learning models Interface with multiple engineering teams across streaming services to spearhead new personalization opportunities Coordinate personalization priorities with global product stakeholders balancing product goals and engineering resources Improve search page engagement by 50% through personalization of landing page Expand personalization to dozens of countries worldwide with unique consumption patterns and content catalogs
Jan 2021 - Jul 2022	Paramount Global Streaming - Applied ML Group, Principal Machine Learning Engineer
Lead a team of four MLEs to develop and deploy production-quality machine learning models Architect integration of personalization features on Paramount+ to deliver a fully-personalized experience to drive content discovery through a large rebrand and catalog expansion Implemented homepage personalization which increased viewing hours from the homepage 14% in 2021 Personalized the order of items within carousels on the homepage increasing clicks by 20%
Apr 2019 - Dec 2020	CBS Interactive - Applied ML Group, Lead Machine Learning Engineer
Lead a team of two MLEs working on recommendations and video processing Spearhead new ML product opportunities including HLS live-stream processing and personalization of CBS All Access.
Jul 2018 - Mar 2019	CBS Interactive - Applied ML Group, Senior Machine Learning Engineer
Search and recommendations product lead: algorithm development, deployment and monitoring for multiple brands including CNET, TV Guide, Metacritic, CBS Sports and CBS All Access Created scalable deep learning based content-to-content recommendations platform utilizing a distributed celery queue to rapidly ingest and recommend content Designed serverless ALS collaborative filtering recommendations platform using Google Cloud Dataproc which went on to be the most clicked-on carousel on the CBS All Access homepage Created highly available and scalable generic recommendation selection and serving API run on Kubernetes serving 1 million recommendations per day
Apr 2017 - Jul 2018	CBS Interactive - 247Sports.com, Data Engineer
Created machine learning spam detection algorithm using Naive Bayes TF-IDF classifier Migrated analytics from custom PHP+MySQL application to AWS Kinesis streaming while maintaining reporting

Skills

Languages	Python, SQL, Bash, terraform
Frameworks	Django, NumPy, Pandas, matplotlib, scikit-learn, Flask, TensorFlow, PySpark
Technologies	Kubernetes, Google Cloud, microservices, Redis, BigQuery
ML Topics	Recommendations, image segmentation, classification, collaborative filtering

Education

Aug 2013 - Mar 2017	Ph.D. in Electrical Engineering Vanderbilt University
Aug 2011 - May 2013	Master's in Business Administration The University of Tennessee at Martin
Aug 2007 - Feb 2011	B.S. in Imaging Science Rochester Institute of Technology

Honors & Awards

2014 - 2017	NEI T32 Training Grant Award
2015	ISMRM Trainee Educational Stipend Award Winner
2012 and 2013	UT Martin Faculty Scholar
2011	RIT Outstanding Undergraduate Scholar Nominee
2010 - 2011	RIT Academic Achievement Scholarship

Speaking Engagements

Apr 2019	A Glimpse into CBS Interactive's AI/ML Group	Google Next '19
Aug 2018	Serverless Streaming Web Analytics with AWS Kinesis and Lambda	Nashville Analytics Summit
Aug 2018	Serverless Streaming Web Analytics with AWS Kinesis and Lambda	Nashville AWS Meetup
Mar 2018	Building a Serverless Recommendation Engine	Brentwood AI Meetup
Apr 2017	On-demand analytics for publishers using a splunk powered chatbot	Nashville Splunk User Group

Teaching Experience

Fall 2015	Vanderbilt University (VU Athletics), Tutor
Spring 2014	Digital Signal Processing (EECE256), TA
Spring 2013	Image Processing (EECE253), TA
Spring 2008 - Spring 2011	RIT Academic Support Center (Drop in calculus and physics tutoring), Lead Tutor

All Publications

Google Scholar

Journal Articles

Synthetic Atlases Improve Segmentation Consistency between T1-Weighted Imaging Sequences A. Plassard, S. Rane, P. D'Haese, S. Pallavaram, D. Claassen, B. Dawant, R. Harrigan, and B. Landman Magnetic Resonance Imaging under review [J1]

Assessment of Orbital Computed Tomography (CT) Imaging Biomarkers in Patients with Thyroid Eye Disease S. Chaganti, K. Mundy, M. DeLisi, K. Nelson, R. Harrigan, R. Galloway, B. Landman, and L. Mawn Journal of Digital Imaging 2019 [J2]

Imaging biomarkers in thyroid eye disease and their clinical associations S. Chaganti, K. Nelson, K. Mundy, R. Harrigan, R. Galloway, L. Mawn, and B. Landman Journal of Medical Imaging 2018 [J3]

Robust Multicontrast MRI Spleen Segmentation for Splenomegaly Using Multi-Atlas Segmentation Y. Huo, J. Liu, Z. Xu, R. Harrigan, A. Assad, R. Abramson, and B. Landman IEEE TBE 2018 [J4]

Quantitative characterization of optic nerve atrophy in patients with multiple sclerosis R. Harrigan, A. Smith, B. Lyttle, B. Box, B. Landman, F. Bagnato, S. Pawate, and S. Smith MSJ-ETC 2017 [J5]

Estimated Incidence of Ophthalmic Conditions Associated with Optic Nerve Disease in Middle Tennessee S. Chaganti, K. Nelson, R. Harrigan, K. Nabar, N. Nandakumar, T. Goecks, S. Smith, B. Landman, and L. Mawn arXiv 2017 [J6]

Disambiguating the optic nerve from the surrounding cerebrospinal fluid: Application to MS-related atrophy R. Harrigan, A. Plassard, F. Bryan, G. Caires, L. Mawn, L. Dethrage, S. Pawate, R. Galloway, S. Smith, and B. Landman ISMRM 2016 [J7]

Automatic Measurement of Optic Nerve Atrophy in Multiple Sclerosis Patients with and without Optic Neuritis in MRI (P3. 013) R. Harrigan, B. Landman, L. Mawn, S. Pawate, and S. Smith AAN 2016 [J8]

Vanderbilt University Institute of Imaging Science Center for Computational Imaging XNAT: A multimodal data archive and processing environment R. Harrigan, B. Yvernault, B. Boyd, S. Damon, K. Gibney, B. Conrad, N. Phillips, B. Rogers, Y. Gao, and B. Landman Neuroimage 2016 [J9]

Robust optic nerve segmentation on clinically acquired computed tomography R. Harrigan, S. Panda, A. Asman, K. Nelson, S. Chaganti, M. DeLisi, B. Yvernault, S. Smith, R. Galloway, and L. Mawn SPIE MI 2014 [J10]

Conference Proceedings

Improved automatic optic nerve radius estimation from high resolution MRI R. Harrigan, A. Smith, L. Mawn, S. Smith, and B. Landman Orlando, Florida 2017 [C1]

Multi-atlas segmentation enables robust multi-contrast MRI spleen segmentation for splenomegaly Y. Huo, J. Liu, Z. Xu, R. Harrigan, A. Assad, R. Abramson, and B. Landman Orlando, Florida 2017 [C2]

Effects of b-value and number of gradient directions on diffusion MRI measures obtained with Q-ball imaging K. Schilling, V. Nath, J. Blaber, R. Harrigan, Z. Ding, A. Anderson, and B. Landman Orlando, Florida 2017 [C3]

Short term reproducibility of a high contrast 3-D isotropic optic nerve imaging sequence in healthy controls R. Harrigan, A. Smith, L. Mawn, S. Smith, and B. Landman San Diego, California 2016 [C4]

Structural functional associations of the orbit in thyroid eye disease: Kalman filters to track extraocular rectal muscles S. Chaganti, K. Nelson, K. Mundy, Y. Luo, R. Harrigan, S. Damon, D. Fabbri, L. Mawn, and B. Landman San Diego, California 2016 [C5]

On the fallacy of quantitative segmentation for T1-weighted MRI A. Plassard, R. Harrigan, A. Newton, S. Rane, S. Pallavaram, P. D'Haese, B. Dawant, D. Claassen, and B. Landman San Diego, California 2016 [C6]

Constructing a statistical atlas of the radii of the optic nerve and cerebrospinal fluid sheath in young healthy adults R. Harrigan, A. Plassard, L. Mawn, R. Galloway, S. Smith, and B. Landman Orlando, Florida 2015 [C7]

TRADITIONAL MBA ADMISSIONS CRITERIA AND GRADUATE SCHOOL SUCCESS: HOW ARE GMAT SCORES, UNDERGRADUATE GPA, AND GRADUATE BUSINESS SCHOOL PERFORMANCE CORRELATED? K. Hammond, M. Cook-Wallace, E. Moser, and R. Harrigan AELJ 2015 [C8]

Posters

Automatic Measurement of Optic Nerve Atrophy in Multiple Sclerosis Patients with and without Optic Neuritis in MRI R. Harrigan, S. Smith, and B. Landman Vancouver, BC, Canada 2016 [S1]

Imaging in the Optic Nerve: Insights into Optic Nerve Pathology R. Harrigan, S. Chaganti, S. Smith, and B. Landman Nashville, Tennessee 2015 [S2]

Optic Nerve Mapping in Multiple Sclerosis Patients with and without Optic Neuritis R. Harrigan, S. Smith, and B. Landman Nashville, Tennessee 2015 [S3]

Mapping of the Optic Nerve in MS Patients with and without Optic Neuritis R. Harrigan, S. Smith, and B. Landman Toronto, ON, Canada 2015 [S4]