ArticleslgStudy

computer science

Liu Gang

Liu Gang is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Liu Gang rather than just read about it. In short: Liu Gang (Chinese: 刘刚; born 30 January 1961) is a Chinese-born American aerospace engineer, computer scientist, optical physicist, political activist, and writer. He founded the Beijing Students' Autonomous Federation.

Key takeaways

  • Liu Gang belongs to computer science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Liu Gang to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Liu Gang from memory before moving on to harder problems.

Reference excerpt

Liu Gang (Chinese: 刘刚; born 30 January 1961) is a Chinese-born American aerospace engineer, computer scientist, optical physicist, political activist, and writer. He founded the Beijing Students' Autonomous Federation. He was a prominent student leader at the Tiananmen Square protests of 1989. Liu holds an M.A. in physics from Peking University and an M.A. in computer science from Columbia University. After his exile to the United States in 1996, Liu studied technology and physics at Bell Labs in New Jersey. Liu was employed at Morgan Stanley as a Wall Street IT analyst.

Student activist As an undergraduate student at University of Science and Technology of China in Hefei, Liu met Fang Lizhi, a pro-democracy activist. Then, at Peking University, Liu organized "Democracy Salons". Wang Dan later held a position there. Liu was a 28-year-old graduate when the 1989 demonstrations began. He organized the Beijing Students' Autonomous Federation and joined the movement's organizing body. As a result, he was sixth on a list of twenty-one activists whose arrests were ordered by the government. Liu went into hiding as a fugitive, but on 15 June 1989, Liu was arrested and charged with attempted subversion of the Chinese Communist Party. In 1991, he was convicted and sentenced to six years imprisonment at Qincheng Prison. After his release from prison in 1996, Liu continued to advocate for human rights in China and organized an underground democracy movement. After moving to the United States, Liu continued his studies at Columbia University in New York City. From there, he continued to support the Chinese democracy movement and in 2011, initiated further pro-democracy protests.

Scientific research

China In 1982, Liu received a bachelor's degree in modern mechanics from the University of Science and Technology of China. He was employed by the Aviation Industry Corporation of China in Shenyang in the field of aerodynamics. He worked in partnership with Luo Yang, and was promoted to head of aircraft design. Liu's field of research was the theory of air resistance, and he worked on problems of double-sided entry and radar technology. In 1984, Liu received a master's degree in optics from the Department of Physics at Peking University in Beijing. While there, he was an assistant teacher. Liu returned to work at the China Soft Science Research Institute but was also acting assistant director at the University of Science and Technology of China. In 1988, Liu became an assistant and associate researcher at the Wear-Resistant Materials Development Company of the National Ministry of Higher Education and the Dalian Institute of Technology. He was then transferred to research in the Department of Physics at the Chinese Academy of Sciences.

United States In 1996, Liu received a master's degree in computer science from Columbia University. He was invited to speak at the New York Academy of Sciences. Liu gained employment as a member of technical staff (MTS) at the Mathematics of Networks and Systems Research Department at Bell Laboratories in Murray Hill, New Jersey. There he worked on Optical telecommunication network design and planning, routing algorithms, optimization techniques, and economic models and strategy analysis. Liu's areas of research included: SPIDER, a design tool for fast-restoration in all-optical networks; VPNStar, a system for provisioning multi-service VPNs with Quality of service guarantees over Internet Protocol; in software design, a management system for Lambda Router in all-optical networks; and analysis of Internet pricing. During his days at Bell Laboratories, Liu introduced the A*Prune (1999, ISSN 0743-166X) with K. G. Ramakrishnan, to describe a new class of algorithm. This opened a new research direction in theoretical science. He found that A*Prune is comparable to the current best known-approximate algorithms for most randomly generated graphs. The algorithm constructs paths, starting at the source and going towards the destination. But, at each iteration, the algorithm is rid of all paths that are guaranteed to violate the constraints, thereby keeping only those partial paths that have the potential to be turned into feasible paths, from which the optimal paths are drawn. Liu also proposed a special class of Optical devices called SPIDER (2001, ISSN 1089-7089); optical routers, dense wavelength division multiplexing (DWDM) systems, and cross-connects of unprecedented capacities. Liu and his colleagues are developing techniques for efficient and reliable optical network design, covering decentralized dedicated protection to shared path-based mesh restoration.

References

External links Quatratic.com — A website solver for Convex Nonlinear Programming

Worked examples

Example 1 — a first encounter with Liu Gang

Start with the simplest possible case. Write down what Liu Gang claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Liu Gang before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Liu Gang ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Liu Gang

In research
Liu Gang appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Liu Gang in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Liu Gang is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1961 births, 1989 Tiananmen Square protesters, 21st-century American engineers, so understanding it makes those chapters shorter.
In everyday life
Look for Liu Gang outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Liu Gang in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Liu Gang means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Liu Gang out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Liu Gang in simple terms?

Liu Gang (Chinese: 刘刚; born 30 January 1961) is a Chinese-born American aerospace engineer, computer scientist, optical physicist, political activist, and writer. He founded the Beijing Students' Autonomous Federation.

Why does Liu Gang matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Liu Gang?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Liu Gang.

Tags

  • 1961 births
  • 1989 Tiananmen Square protesters
  • 21st-century American engineers
  • 21st-century American physicists
  • American aerospace engineers
  • American computer programmers
  • American computer scientists
  • Chinese dissidents
  • Chinese emigrants to the United States
  • Chinese human rights activists
  • Chinese political writers
  • Chinese revolutionaries

Keep exploring