>From: Francis Heylighen <email@example.com>
>>September 13, 2001
>>Better Networks: Look to Nature
>>By KATIE HAFNER
>>Benoît Doppagne for The New York Times
>>Marco Dorigo, a computer scientist at the Free University of Brussels, in
>>his office. Guided by ant behavior, he is studying ways to improve
>>HE Internet is an engineering feat of no small magnitude. It operates
>>using a method of data transmission invented in the 1960's called packet
>>switching. Send e-mail, for instance, and your message is broken into any
>>number of little bundles; each takes a separate route and reunites with
>>the others at the destination.
>>Over the ensuing decades, as the Internet turned from an academic and
>>military tool into a mass medium, only the efficiencies of packet
>>switching have enabled it to meet demand. Even so, as any Web user or
>>e-mail correspondent can attest, traffic can still be congested and
>>Now ideas for advances in data routing are beginning to emerge from a
>>surprisingly simple model: the ant.
>>Indeed, applying the study of ants to complex engineering problems is
>>something of an intellectual trend. The topic drew attention at a recent
>>international conference on artificial intelligence in Seattle. It has
>>been discussed in a variety of scientific journals. And a new book by
>>Steven Johnson, "Emergence: The Connected Lives of Ants, Brains, Cities
>>and Software" (Scribner), points to ant behavior as a way to further,
>>among other things, understanding of the World Wide Web.
>>What makes ants worth studying, if not emulating? For one thing, they
>>exhibit something called swarm intelligence. That is, the teamwork of
>>social insects is decentralized. Individually, an ant's actions are
>>primitive, but collectively, they result in efficient solutions to
>>complex problems like finding the shortest route between the nest and a
>>The key to ants' efficiency is their ability to lay down trails in their
>>communal travels with a chemical called pheromone. Over time, those
>>trails result in a system of routing. The lesson, in short, is follow the
>>So to build better data networks, researchers are creating what might be
>>viewed as artificial ants: small pieces of software that travel through a
>>network depositing artificial pheromone (pronounced FARE-uh-moan) as they
>>seek optimal routes.
>>"By bending the rules of behavior, you can increase the performance of
>>the system while keeping the spirit of what the ants do," said Vincent
>>Darley, an ant-behavior specialist and research scientist in the London
>>office of BiosGroup, a company based in Santa Fe, N.M., that develops
>>science-based software, routing and marketing strategies for corporations.
>>Bending the rules can involve giving the ants a memory and enabling them
>>to retrace a particularly good route so that they can mark it with extra
>>pheromone — something that real ants do not do.
>>"Throw a bunch of virtual ants into the cities and each tries to build a
>>route," said Éric Bonabeau, a physicist and network engineer who has
>>studied ants and data networks and is the chairman and chief scientist of
>>Icosystem, a consulting company in Cambridge, Mass.
>>Marco Dorigo, a professor of computer science at the Free University of
>>Brussels, has borrowed the ant approach to solve a classic puzzle in
>>mathematics called the traveling salesman problem. The challenge is to
>>find the shortest route connecting many different cities — a priority not
>>only for sales forces but also for systems delivering people, parcels or
>>packets of Internet data.
>>As the number of cities involved increases, the difficulty of the problem
>>can increase exponentially. Just a dozen cities present billions of
>>possibilities. Apply ant behavior to the traveling salesman problem,
>>however, and solutions start to present themselves.
>>In Dr. Dorigo's model, the pheromone deposited along the longer routes
>>evaporates, leaving the links to the greatest number of short routes most
>>densely covered with the chemical. When the artificial ants go out again,
>>they rely on tables storing information about the amount of pheromone on
>>Dr. Dorigo has found that repeated trips result in progressively shorter
>>overall trips. Such work is directly applicable to data networks,
>>especially the Internet, where traffic is highly unpredictable. Because
>>the artificial ants in such a model are constantly exploring different
>>routes, a host of alternatives surface whenever a particular route goes
>>out of commission.
>>Dr. Dorigo, who has tested the formulas that he has developed on a
>>simplified simulator of a packet-switched network that he calls AntNet,
>>said his aim was to address the shortcomings of routing mechanisms in
>>systems like the Internet.
>>The experimental models "are a method for finding very good solutions in
>>a reasonably short time," he said. "They may not be provably optimal, but
>>they're very good, which is often what is required in real-world applications."
>>Dr. Bonabeau said that such models would lead to more efficient, reliable
>>and robust networks. "But I think the revolution is in the way people
>>think about networks," he added.
>>"The Internet is a deeply distributed system, yet people think about how
>>to regulate its traffic with a centralized mind-set. Swarm-base
>>decentralized control will lead to entirely new ways of designing networks."
>>Still, the advances in ant-based networking research have yet to be put
>>into practice on an actual commercial network, Dr. Bonabeau said. To do
>>so would require expensive and cumbersome modifications to routing equipment.
>>Decision makers at communications companies have generally been slow to
>>embrace the concept, he said. "Especially at France Télécom," where he
>>was a network engineer, "it's very hard to convince them to let go and
>>leave the network to ants," he said.
>>Southwest Airlines (news/quote) has applied some of the lessons of the
>>ant model to its cargo shipping with aid from BiosGroup. The cargo
>>solution, said Ruud Schoonderwoerd, a consultant at Pricewaterhouse
>>Coopers who did some of the early work on ants and routing, illustrated
>>the importance of balancing network traffic.
>>"You can optimize something locally but it won't have a global effect,"
>>he said. "Sometimes it's better to have some routes go a longer distance
>>so the network as a whole is more balanced." For example, if Southwest
>>tried to route each package on the first or shortest flight, bottlenecks
>>could develop that would hamper its routing over all.
>>Dr. Darley of BiosGroup has applied ant behavior to solving scheduling
>>problems in complex manufacturing settings and to routing and production
>>decisions at a natural gas company in Texas.
>>"In any of these problems, we take the abstract idea of ants' depositing
>>pheromone and we try to form the right analogy so we can apply the right
>>technique," Dr. Darley said. "By attaching artificial pheromones to these
>>various possible decisions, a colony of ants can learn over time what the
>>best things to do are. So the idea is when this factory breaks down, they
>>learn they have to start buying gas from a different factory."
>>Or consider the exploration of a big database of clients, like that
>>maintained by a bank. Virtual ants can be set loose to wander the
>>database, picking up pieces of information and depositing them according
>>to various criteria, resulting in clusters of clients with common
>>attributes — much the way ants amass clusters of seeds for their
>>pantries, for example.
>>"Ant-based algorithms have the potential to improve the efficiency and
>>reliability of many kinds of complex, dynamically changing systems which
>>involve routing," Mr. Schoonderwoerd said. "This could be a
>>telecommunications network such as the Internet, logistic systems such as
>>factory lines or public transport systems, or perhaps even the design of
>>Understanding ant behavior could also lead to more effective use of the Web.
>>Mr. Johnson, the author of "Emergence," said that there are distinct
>>parallels between ant colonies and cities — and by extension, the Web —
>>in the ways communities are formed.
>>"If you have an ant colony that only has five ants in it, you can't do
>>the kind of complex processing that an ant colony does so well," he said.
>>"You need 10,000 ants for it to do its magic. And for a city neighborhood
>>to form, you need a big population to see these self-organizing clusters
>>of like-minded people forming."
>>Similarly, he said, the seeming chaos of the Web's unfettered expansion
>>could in fact make it more efficient. "We're now building structures on
>>the Web that get more useful and more organized as they get bigger, and
>>in some ways that's what ant colonies and cities do," he said.
>>The Google search engine, for example, "tracks local decisions made by
>>individuals to surf from one site to another or add a link from one page
>>to another, and looks for larger patterns in those decisions," he said.
>>Thus it ranks results based on the "shared sensibility" of a community.
>>Likewise, he cited the software program Alexa, a type of Web directory
>>that can show sites related to the one the user is visiting. Like Google,
>>Alexa inspects patterns of Web traffic and links sites in a way that
>>might not otherwise seem obvious.
>>"Alexa is a way of solving the problem of organizing the Web from the
>>bottom up instead of the top down," he said. "Alexa says, `O.K., these
>>sites are related because of the patterns of usage,' so out of that a
>>higher-level intelligence emerges."
>>Dr. Bonabeau said he saw a strong similarity between an ant colony and a
>>so-called peer-to-peer community, a network in which individual computers
>>are directly connected without the need for a central intermediary.
>>Napster and other music-sharing services have been prominent if not
>>notorious examples of such networks; others have been set up to evade
>>government censorship of the Web in some countries.
>>Dr. Bonabeau is working to develop ant- based technology that would make
>>peer-to- peer communities more efficient and foster more synergy within them.
>>"Peer-to-peer computing, be it peer-to- peer communities, instant
>>messaging or distributed computing, is a terrific example of where
>>networks might go," Dr. Bonabeau said. "The question is, do networks as
>>they exist today really support what people want to do with them? The
>>answer is clearly no."
>Dr. Francis Heylighen <firstname.lastname@example.org> -- Center "Leo Apostel"
>Free University of Brussels, Krijgskundestr. 33, 1160 Brussels, Belgium
>tel +32-2-6442677; fax +32-2-6440744; http://pespmc1.vub.ac.be/HEYL.html
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