Bitcoin development platform

Work on the Connectivity Lab project Terragraph, which was just announced @ FB. One major part I'm working on is Open/R (https://code.facebook.com/posts/1142111519143652/introducing-open-r-a-new-modular-routing-platform/), a new modular routing platform.

(1) Physical-Ratio-K based Scheduling Protocol (PRKS)PRKS is the first-ever practical distributed scheduler to ensure reliability of wireless communication while maximizing throughput, eliminating the fundamental decade-old hidden-terminal issue.o Designed the architecture of PRKS: split code into reusable encapsulated components, grouped components with coupled functionalities, and organized groups in a tree hierarchy.o Implemented, single-handedly, PRKS, its two variants, and four state-of-the-art protocols from scratch, on sensors with only 48kB ROM, 10kB RAM, and 8MHz 16-bit MCU using TinyOS. The source code (~58,000 lines) is available at \url{https://github.com/xhliu/prks}.o Deployed these protocols in two sensor network testbeds of 127+ nodes.o Increased link reliability from as low as 0\% in the state of the art to 95\% in PRKS.(2) Multi-Timescale Adaptation (MTA) Routing Protocol MTA is the best distributed routing protocol for delivering probabilistic real-time traffic.o Implemented, independently, MTA, its seven variants, and four other protocols from the ground up in TinyOS. Code (~16,000 lines) is at \url{https://github.com/xhliu/mta}.o Modified TinyOS kernels systematically to make code run concurrently and enable real-time computing, including radio stack, time synchronization, and resource arbitration.o Increased deadline success ratio by 89\% and reduced transmission cost by a factor of 9.7, shown by measurements in two testbeds of 127+ nodes.

Organized programming competitions and invited speakers to give technical talks.

LifeCode is a remote health monitoring system to compete in Microsoft Imagine Cup.o Built a Windows mobile phone application in C# to receive and display real-time heartbeat rates collected by sensors and transmitted to the phone via Bluetooth.

(1) Students in lab course CSC1000 report machine breakdowns by filing tickets in this web-based system, where IT personnel can track and update the status of each ticket.o Modified database schema and wrote PHP code to enable users to insert, update, delete, search, and dump tickets via a web interface using the Linux, Apache, MySQL, and PHP (LAMP) stack.(2) Taught CSC1000 Introduction to Computer Science.

Microsoft Forefront Security (MFS) is a business anti-virus software product that can be controlled over the network.o􏰀 Automated tests using MS-DOS scripting by partnering with the development team.o􏰀 Run unit and end-to-end tests of MFS on remote machines with different Windows families, CPUarchitectures, and languages; investigated test failures and performed root-cause analysis.􏰀o Found bugs and filed detailed and high-quality error reports in the bug tracking database; trackedthem and verified they were fixed.

Trinity Studio is a studio I co-founded with three classmates, building websites for small businesses, government agencies, and universities.o Designed database schema using SQL Server and Access.o Developed back end using ASP, IIS, and ODBC.