Liu Gang

Liu Gang
Born	(1961-01-30) January 30, 1961 China
Occupation(s)	Aerospace engineer, optical physicist, computer scientist, political activist, author
Years active	1982–present
Known for	Leadership in 1989 Tiananmen Square protests; A*Prune algorithm; SPIDER optical devices

Liu Gang (Chinese: 刘刚; born 30 January 1961) is an aerospace engineer, optical physicist, computer scientist, political activist, and author originally from China who later became an American citizen. He established the Beijing Students' Autonomous Federation and emerged as a prominent student leader during the Tiananmen Square protests of 1989. Liu earned a master's degree in physics from Peking University and another in computer science from Columbia University. After being exiled to the United States in 1996, he engaged in research at Bell Labs located in New Jersey and served as an IT analyst at Morgan Stanley on Wall Street.

Student activist

During his undergraduate studies at the University of Science and Technology of China in Hefei, Liu encountered the pro-democracy advocate Fang Lizhi. While attending Peking University, he organized "Democracy Salons," which featured participants such as Wang Dan.

At age 28, Liu played a central role in founding the Beijing Students' Autonomous Federation amid the 1989 protests and was part of the movement's leadership team. He was ranked sixth on a government list of twenty-one activists targeted for detention. After going underground, he was arrested on 15 June 1989 and accused of attempted subversion against the Chinese Communist Party. In 1991, Liu received a six-year prison sentence at Qincheng Prison.

Upon his release in 1996, Liu persisted in his human rights advocacy within China and contributed to organizing a covert democracy movement. After moving to the United States, he resumed his academic pursuits at Columbia University and remained engaged in promoting Chinese democratic reforms, including spearheading demonstrations during the 2011 Chinese pro-democracy movement.

China

Liu graduated with a bachelor's degree in modern mechanics from the University of Science and Technology of China in 1982, after which he joined the Aviation Industry Corporation of China in Shenyang, concentrating on aerodynamics. Collaborating with Luo Yang, he advanced to lead aircraft design processes. His scientific investigations focused on aerodynamic resistance theories, bidirectional entry phenomena, and aspects of radar technology.

In 1984, Liu earned a master's degree specializing in optics from the Department of Physics at Peking University in Beijing, where he also held a position as assistant instructor. Subsequently, he returned to work at the China Soft Science Research Institute and took on responsibilities as assistant director at the University of Science and Technology of China.

By 1988, Liu held roles as assistant and associate researcher at the Wear-Resistant Materials Development Company affiliated with the National Ministry of Higher Education & the Dalian Institute of Technology, before transferring to the Department of Physics at the Chinese Academy of Sciences.

United States

In 1996, Liu completed his master's degree in computer science at Columbia University and was invited to present at the New York Academy of Sciences. He joined Bell Laboratories in Murray Hill, New Jersey, serving as technical staff within the Mathematics of Networks and Systems Research Department. His research encompassed optical telecommunication network architecture, routing algorithms, optimization strategies, economic modeling, and strategic evaluations.

Among his projects were SPIDER, designed for rapid restoration in all-optical networks; VPNStar, which provisions multi-service VPNs with Quality of Service assurances over Internet Protocol; Lambda Router management systems; and analyses related to Internet pricing structures.

At Bell Labs, Liu co-created the A*Prune algorithm (1999) alongside K. G. Ramakrishnan. This algorithm contributed to theoretical advancements by efficiently identifying multiple constrained shortest paths while pruning infeasible routes early to streamline pathfinding.

He also introduced SPIDER optical devices (2001), including optical routers and dense wavelength division multiplexing (DWDM) systems with substantial capacity. His team made significant progress toward designing optical networks that are both efficient and reliable by implementing decentralized protection schemes and shared path-based mesh restoration techniques.

External links

• Quatratic.com — Online solver specializing in Convex Nonlinear Programming