Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sensor network mimics synchronized calling by frogs and cicadas

17.11.2004


The modern world is filled with the uncoordinated beeping and buzzing of countless electronic devices. So it was only a matter of time before someone designed an electronic network with the ability to synchronize dozens of tiny buzzers, in much the same way that frogs and cicadas coordinate their night-time choruses.



"Several years ago I was on a camping trip and we pitched our tent in an area that was filled with hundreds of tree frogs," says Kenneth D. Frampton, an assistant professor of mechanical engineering at Vanderbilt University, who dreamed up the project. "The frogs were so loud that I couldn’t get to sleep. So I began listening to the chorus and was fascinated by how the pattern of synchronized calling moved around: Frogs in one area would croak all together for a while, then gradually one group would develop a different rhythm and drift off on its own."

Last summer’s emergence of cicada brood X brought back that memory and prompted Frampton to assign undergraduates Efosa Ojomo and Praveen Mudindi--working under the supervision of graduate student Isaac Amundson--with the task of simulating this complex natural behavior using a wireless distributed sensor network. They presented the results of their project on Nov. 16 at the annual meeting of the American Acoustical Society in San Diego.


Consulting the literature about animal vocalizations, the engineers discovered that a number of different theories have been advanced to explain such naturally occurring synchronized behaviors. They may have evolved cooperatively in order to maximize signal loudness, to confuse predators or to improve call features that attract potential mates. Or they may have evolved competitively in order to mask or jam the calls of nearby animals. "Whichever theory is true, it is clear that these behavior patterns are complex and offer an interesting inspiration for group behaviors," says Frampton.

One thing that these behaviors have in common is that they are produced by groups of animals who are in communication with each other but who are acting on their own. Networks consisting of nodes that communicate with each other but act independently according to simple rules are becoming increasingly popular and were the obvious system to use. "There is a great deal that we do not yet know about the group behavior of such systems," says Frampton. "So, in addition to being a lot of fun, the synchronized calling experiment is adding to our understanding of the behavior of this kind of network."

The engineers began with a wireless network of 15 to 20 "Motes," a wireless network designed by computer scientists at the University of California, Berkeley and manufactured commercially by Crossbow Inc. These are small microprocessors equipped with wireless communications. The researchers added a microphone and a buzzer to each node.

To mimic synchronized calling behaviors, the researchers first programmed a single leader, dubbed the alpha node, to begin calling (buzzing) with an arbitrary duration and frequency. The alpha node was set so it called at this rate regardless of any other calling in its vicinity. The remainder of the devices, referred to as beta nodes, were programmed differently. They were instructed to listen with their microphones and when they hear a call that is sufficiently loud, to estimate its duration and frequency and then begin calling in synch with the detected call. "Although this behavioral algorithm is quite simple, it produces some interesting group behaviors," Frampton reports.

When all is quiet and an alpha node begins calling, at first only those beta nodes nearby hear the call and respond. Then, as more betas swell the chorus, nodes farther away hear the call and join in. In this fashion, synchronized calling gradually spreads concentrically out from the alpha node until all the nodes are synchronized.

A second interesting behavior occurs when a beta node "hiccups" and starts buzzing out of synch with its neighbors. Such hiccups can be caused by measurement noise, operating system jitter and other factors. Occasionally, when such a hiccup occurs, neighboring nodes resynchronize to the errant node. Normally, these transients quickly disappear as the wayward group resynchronizes with the larger group.

The most interesting behavior pattern appeared when the researchers introduced a third kind of node that they labeled omega. This node was programmed identically to an alpha node but set to a different duration and frequency. When introduced into the array, an omega node begins to attract neighboring nodes to its call cycle. Unlike the hiccup case, however, the omega group does not resynchronize with the original group. Rather, the omega node eventually recruits a growing number of nodes to its calling cycle until a "balance of power" is reached with the alpha node. The eventual balance between the two groups depends strongly on the initial arrangement of the sensors.

"While this is a rather whimsical application of a sensor network, it demonstrates the unique system behaviors that can arise in truly distributed processing," says Frampton. Even when nodes follow very simple rules, the behavior of the group can be quite complex. Although this project is not likely to improve knowledge on synchronized calling in nature, it does demonstrate the types of complex behavior patterns that will be important for future developments in sensor networks, Frampton says.

David F. Salisbury | EurekAlert!
Further information:
http://www.vanderbilt.edu

More articles from Power and Electrical Engineering:

nachricht Silicon solar cell of ISFH yields 25% efficiency with passivating POLO contacts
08.12.2016 | Institut für Solarenergieforschung GmbH

nachricht Robot on demand: Mobile machining of aircraft components with high precision
06.12.2016 | Fraunhofer IFAM

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

Decoding cement's shape promises greener concrete

08.12.2016 | Materials Sciences

Will Earth still exist 5 billion years from now?

08.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>