Principal Member of Technical Staff - Research @ AT&T Labs - Research
Postdoctoral Research Associate @ Princeton University
Shanghai Jiao Tong University
Senior Software Engineer @ Build an exchange platform to store network configuration data on a globally-distributed database. Key challenges are to store/retrieve millions of records on the fly and quickly respond to an arbitrary query from billions of records. In particular, I optimize database design and rewrite the core code to reach performance goals with saving space
Senior Software Engineer @ Build an exchange platform to store network configuration data on a globally-distributed database. Key challenges are to store/retrieve millions of records on the fly and quickly respond to an arbitrary query from billions of records. In particular, I optimize database design and rewrite the core code to reach performance goals with saving space usage by 95% and speeding up 100+ times for most latency-sensitive APIs. I also develop the distributed locking and rollback scheme to ensure atomicity and consistency. In addition, I design and implement a novel and scalable access control based on prefix for general usages.
Prototype an Android App for social networks. From January 2014 to Present (2 years) Greater New York City AreaPrincipal Member of Technical Staff - Research @ Designed and implemented BIRDSEYE for information retrieval and flexible graphical user interaction for network design and management. BIRDSEYE has been successfully used in various internal tools, including AT&T long-haul DWDM network planning, AT&T IPTV network (UVerse) topology monitoring, AT&T metro network design, etc. (Java).
Core AT&T investigator for DARPA CORONET project to architect next-generation long-distance IP-over-Optical-Layer networks. Built a routing engine for very rapid provisioning of new IP/private line connections or dynamic wavelength services with very fast restoration (C++).
Developed a novel two-step approach to provision multiple physically-diverse high-speed circuits over AT&T core DWDM network with pre-processing using Integer Linear Programming for diverse routing and post-processing for regenerator placement and wavelength assignment. The approach produces most near-optimal routes within 1 minute, which is fully acceptable to network planners for real-time interaction.
Led a multi-institution team to investigate the interference of data and voice on drop calls in AT&T cellular network.
Led the research on simple and efficient failure resilient load balancing, which is awarded as the best student paper in ACM SIGMETRICS'11. From October 2007 to January 2014 (6 years 4 months) Postdoctoral Research Associate @ Solved optimal traffic engineering using link-state routing with convex optimization.
Investigated ubiquitous 100Mbps broadband access over twisted pair (telephone) network through joint optimization of resources in Frequency, Amplitude, Space, and Time domains.
Explored secure communication protocols for lightweight ad hoc networks made of pocket devices, embedded systems and portable mobile devices. From August 2005 to October 2007 (2 years 3 months)
Ph.D., Computer Science and Engineering @ University at Buffalo From 1999 to 2005 B.S, Applied Electronics @ Shanghai Jiao Tong University From 1992 to 1996 Dahai Xu is skilled in: Perl, Linux, Wireless, Algorithms, C++, LTE, Distributed Systems, Java, Optimization, LaTeX, OPNET, PHP, AMPL, CPLEX, Matlab
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