Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

China's Eye on the Internet

13.09.2007
The "Great Firewall of China," used by the government of the People's Republic of China to block users from reaching content it finds objectionable, is actually a "panopticon" that encourages self-censorship through the perception that users are being watched, rather than a true firewall, according to researchers at UC Davis and the University of New Mexico.

The researchers are developing an automated tool, called ConceptDoppler, to act as a weather report on changes in Internet censorship in China. ConceptDoppler uses mathematical techniques to cluster words by meaning and identify keywords that are likely to be blacklisted.

Many countries carry out some form of Internet censorship. Most rely on systems that block specific Web sites or Web addresses, said Earl Barr, a graduate student in computer science at UC Davis who is an author on the paper. China takes a different approach by filtering Web content for specific keywords and selectively blocking Web pages.

In 2006, a team at the University of Cambridge, England, discovered that when the Chinese system detects a banned word in data traveling across the network, it sends a series of three "reset" commands to both the source and the destination. These "resets" effectively break the connection. But they also allow researchers to test words and see which ones are censored.

Barr, along with Jed Crandall, a recent UC Davis graduate who is now an assistant professor of computer science at the School of Engineering, University of New Mexico; UC Davis graduate students Daniel Zinn and Michael Byrd; and independent researcher Rich East sent messages to Internet addresses within China containing a variety of different words that might be subject to censorship.

If China's censorship system were a true firewall, most blocking would take place at the border with the rest of the Internet, Barr said. But the researchers found that some messages passed through several routers before being blocked.

A firewall would also block all mentions of a banned word or phrase, but banned words reached their destinations on about 28 percent of the tested paths, Byrd said. Filtering was particularly erratic at times of heavy Internet use.

The words used to probe the Chinese Internet were not selected at random.

"If we simply bombarded the Great Firewall with random words, we would waste resources and time," Zinn said.

The researchers took the Chinese version of Wikipedia, extracted individual words and used a mathematical technique called latent semantic analysis to work out the relationships between different words. If one of the words was censored within China, they could look up which other closely related words are likely to be blocked as well.

Examples of words tested by the researchers and found to be banned included references to the Falun Gong movement and the protest movements of 1989; Nazi Germany and other historical events; and general concepts related to democracy and political protest.

"Imagine you want to remove the history of the Wounded Knee massacre from the Library of Congress," Crandall said. "You could remove 'Bury My Heart at Wounded Knee' and a few other selected books, or you could remove every book in the entire library that contains the word 'massacre.'"

By analogy, Chinese Internet censorship based on keyword filtering is the equivalent of the latter -- and indeed, the keyword "massacre" (in Chinese) is on the blacklist.

Because it filters ideas rather than specific Web sites, keyword filtering stops people from using proxy servers or "mirror" Web sites to evade censorship. But because it is not completely effective all the time, it probably acts partly by encouraging self-censorship, Barr said. When users within China see that certain words, ideas and concepts are blocked most of the time, they might assume that they should avoid those topics.

The original panopticon was a prison design developed by the English philosopher Jeremy Bentham in the 18th century. Bentham proposed that a central observer would be able to watch all the prisoners, while the prisoners would not know when they were being watched.

The work will be presented at the Association for Computing Machinery Computer and Communications Security Conference in Alexandria, Va., Oct. 29-Nov. 2, 2007.

Andy Fell | EurekAlert!
Further information:
http://www.ucdavis.edu

More articles from Information Technology:

nachricht Stable magnetic bit of three atoms
21.09.2017 | Sonderforschungsbereich 668

nachricht Drones can almost see in the dark
20.09.2017 | Universität Zürich

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>