Professional Experiences

Facebook in Seattle, WA
01/2018 - present. Tech Lead, Ads Ranking
  • Lead a team of 7 engineers responsible for the training data infrastructure, powering model training for ads ranking
  • Drive roadmap, directions, and prioritization for building the new generation of ads training data platform to scale up the ads' end-to-end machine-learning model training systems
07/2017 - 12/2017. Senior Software Engineer, Ads Ranking
  • Designed and built the framework to create long-aggregation features in order to capture the ranking signals in a longer history of ads data, delivering +1% incremental Facebook revenue. 
  • Built asynchronous model selection logic in core ads ranking business logic flow, cutting +3% latency in serving relevant ads on Facebook
  • Orchestrated the migration of training data pipelines at PB level with 5+ machine learning engineers onto a new training data service, which resulted in +2% incremental Facebook revenue. 
  • Supported ~5 ads product teams and 20+ machine learning engineers for training data infra needs
08/2016 - 06/2017. Software Engineer, Ads Ranking
  • Built the unified calculation of ads' bidding prices in mobile news feed for ads ranking products, enabling easier customization and faster development of new ads products for our machine learning engineers. 
  • Designed and built a new offline-data-based ads training data joiner to enable long-attribution-window ads conversion ranking products, which account for >10% of Facebook ads revenue. 
  • Built and launched the shadow-traffic-based testing framework for the ads training data stream joining service, shortening the develop/test cycle of this service to <10 minutes. 

06/2015 - 08/2016. Cambridge, MA
Senior Software Engineer, Cloud Foundation (07/2016 - 08/2016)
Software Engineer, Cloud Foundation (06/2015 - 06/2016)
  • Project: Platform as a Service (PaaS) for Hybrid Cloud (11/2015 - 08/2016)
    • Tech lead on designing and developing a PaaS system for enterprises in hybrid-cloud environment. 
    • Built the PaaS system to automatically deploy and manage virtual machines and Docker container applications across EVO-based private cloud and Amazon Web Services. 
  • Project: Automatic Server Provisioning in Datacenters (06/2015 - 05/2016)
    • Built software to automatically discover, bootstrap, and provision servers for datacenter expansion. 
    • Shortened the server addition process from several days to <20 minutes. 
    • Released the software as part of VMware Cloud Foundation software suite. 
06/2012 - 05/2014. Redmond, WA
Software Engineer (in absentia from Princeton University)
Azure Cloud Networking Team (a.k.a., Bing Autopilot Team)
  • Project: Network-State Management Service (03/2013 - 05/2014)
    • Designed and built a network operating system for automatic and safe infrastructure management.
    • Deployed the system in over 10 Azure datacenters across the globe, managing over 10 thousand devices.
    • Reduced the development cost of management applications by 5 times.
    • The system is now the foundation layer of Azure's networking services to its customers (part of Azure Service Fabric).
  • Project: Automatic Latency Diagnosis in Multi-tier Web Services (06/2012 - 02/2013)
    • Designed and built a self-adapting real-time diagnosis system for high search-query latencies.
    • Integrated into Bing's index service, document service, and internal big-data analysis platform.
    • Accurately pinpointed the services and servers that caused high search latencies in several incidents.
    • Contributed to the improvement of user-experiencing latency of Bing.

Princeton University
12/2010 - 05/2012 & 06/2014 - 05/2015. Princeton, NJ
Research Assistant & PhD student in Prof. Jennifer Rexford's group
  • Project: Sprite: Scalable Programmable Inbound Traffic Engineering (06/2014 - 05/2015)
    • Designed and built a scalable distributed system to directly control the entrance point of traffic from cloud services to enterprises in per-connection granularity.
    • In collaboration with and being deployed on the campus network of Princeton University. 
  • Project: HONE: Programmable Host-Network Traffic Management (06/2011 - 05/2012)
    • Realized more effective datacenter-traffic management by extending to include Linux network stack.
    • Integrated with Verizon/Overture Networks's products for business cloud services at the edge.
  • Project: Identifying Performance Bottlenecks in CDNs through TCP-Level Monitoring (12/2010 - 05/2011)
    • Built a TCP profiler in Linux network stack for performance diagnosis of web services.
    • Deployed in the Coral content distribution network.
    • Improved the CDN's overall latency by 10% by locating and resolving its bottlenecks.

Microsoft Research Asia
12/2009 - 03/2010. Beijing, China
Research Intern in Datacenter Network group with Dr. Chuanxiong Guo
  • Project: Virtualized Datacenter Network
    • Built the control module in a virtualized data center network architecture with bandwidth guarantees. 
    • Carried out experiments in datacenters to validate link failure handling and adjustment of bandwidth guarantees.

University of Southern California
07/2009 - 08/2009. Los Angeles, CA
Research Intern in Prof. Urbashi Mitra's group
  • Project: Underwater Acoustic Communication System
    • Designed a channel estimator to improve underwater acoustic wireless communication.
    • Deployed and tested in a Naval testbed.