Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

From butterfly wings to single e-mail, if one action can cause a torrent

16.02.2004


"Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?" Zoologist Konrad Lorenz once asked in postulating the "butterfly effect," the idea that the flapping of fragile wings could start a chain reaction in the atmosphere. In today’s world of the Internet the question might be rephrased: Can a single e-mail from Brazil set off a torrent of action in Texas?



Sociologists postulate that what a few influential leaders think and say can spread and grow and bring about big changes in the thinking of large numbers of people. The Internet offers a compelling new place to look for this phenomenon by studying very large groups and especially, seeing how groups change over time.

But how do you find those influential people? Computer scientists at Cornell University, Ithaca, N.Y., have some suggestions. Their ideas could be applied to such diverse goals as selling a new product, promoting new agricultural techniques in developing countries, predicting the spread of a disease or identifying leaders of terrorist organizations.


Jon Kleinberg, Cornell professor of computer science, discussed the problem, and some computer algorithms to solve it, in a talk on Feb. 15 at the annual meeting of the American Association for the Advancement of Science (AAAS) in Seattle. His talk was part of a symposium on "Community Structure of the Internet and World Wide Web: Mathematical Analyses." His research collaborators were Eva Tardos, Cornell professor of computer science, and former post-doctoral research associate David Kempe, now at the University of Washington.

A common approach used by sociologists is to interview every member of a group and find out who associates with whom -- essentially a snapshot of one moment. Collaboration with computer scientists now makes it possible to send out Web crawlers to map the communications links in a group, something that can be done repeatedly over time, and with much larger groups.

Groups on the Internet can take many forms, including Usenet and chatroom discussion groups, e-mail mailing lists and links between Web sites on related topics. Most recently, the writers of personal online journals known as Web logs, or "blogs," have begun to link to one another and comment on each other’s work.One way to find the influential people would be to identify those who have the most links to others, or the ones who can reach the largest number of others with the fewest "hops" through other people. That, Kleinberg says, introduces redundancy: the two or three top candidates could all link to the same subset of the network. So, Kleinberg suggests, "After targeting the first few people you discount others, then you look for people who are still influential but in diverse parts of the network."

The researchers tested their algorithm on another kind of network, the pattern of co-authorship in scientific papers. Their data pool was the online E-print Archive of physics and mathematics publications, commonly known as the arXiv, maintained by Cornell University Library. People were considered to be linked when they co-authored papers. The studies ignored any real-world information, such as whether two people might be at the same institution. In simulations Kleinberg and colleagues found that their method significantly outperformed methods that rely solely on counting links or measuring the distance between candidates and the rest of the network.

Kleinberg also has been studying the way networks grow over time, working with David Liben-Nowell, a Ph.D. student at the Massachusetts Institute of Technology. One goal is to try to predict where new links will form in a network. In the arXiv network, the researchers hypothesized that two people who haven’t been linked would be likely to form a link if they are near one another in linkage terms. What they found, however, was that the number of hops was not the best measure of nearness. The reason, Kleinberg says, is the "small world phenomenon" -- the fact that everyone is on average "six degrees of separation" from everyone else -- so counting the number of hops between people doesn’t help. "It’s better to look for people who have many different short paths connecting them, " he says. "This is an interesting open question with a lot of room for further research."

Bill Steele | Cornell News
Further information:
http://www.news.cornell.edu/releases/Feb04/AAAS.Kleinberg.ws.html

More articles from Communications Media:

nachricht On patrol in social networks
25.01.2017 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO

nachricht Tile Based DASH Streaming for Virtual Reality with HEVC from Fraunhofer HHI
03.01.2017 | Fraunhofer-Institut für Nachrichtentechnik Heinrich-Hertz-Institut

All articles from Communications Media >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>