Search Pattern Algorithm Inspired by Moths and Bird Flocking

Innovation: Academia

University of Trieste

2020

Image: Martin Vysoudil / Unsplash / CC BY SA - Creative Commons Attribution + ShareAlike

Sense Chemicals (Odor, Taste, etc.) From the Environment

Chemicals are important for signaling and communication among living systems, either intentionally (such as when two living systems try to find one another) or unintentionally (such as when a plant emits a chemical signal that an herbivore can use to find a tasty bite). They are also important for other uses, such as navigating or finding sources for minerals. But chemical signals are often relatively weak and disperse when moving through water or gases. Therefore, detecting them requires specialized abilities, including a way to determine where they are coming from. A well known example of sensing chemicals can be seen in ants following a pheromone trail laid down by others in their colony to locate a quality and abundant food source.

Search this Function

Coordinate by Self-Organization

To create and maintain a healthy community of individuals and ecosystems requires that living systems coordinate their activities. Coordination doesn’t necessarily mean that there’s a leader orchestrating what happens. In nature, coordination is usually achieved through self-organization. In a flock of geese flying in a V-formation, for example, there’s no lead goose controlling where all of the others fly. The flock uses this formation because each goose gains energy from air vortices created by the goose in front of it. The lead goose doesn’t gain that benefit, so when it tires, it moves back and another goose takes the front position.

Search this Function

Efficient search algorithm from University of Trieste uses a combination of individual and neighboring data to improve the detection of harmful substances.

Benefits

Increased efficiency
Improved search time

Applications

Chemical detection
Search and rescue

UN Sustainable Development Goals Addressed

Goal 3: Good Health & Wellbeing

The Challenge

Certain harmful gases and volatile substances can be undetectable by humans but still have the potential to be deadly. The United States’ Occupational Health and Safety Administration (OSHA) estimates approximately 50,000 deaths each year are related to chemical exposures in the workplace. Some of these deaths are related to undetected gaseous hazards, and could be mitigated with earlier detection.

Innovation Details

The search algorithm is used by a group of robots trying to detect a harmful gas. It is based on the assumption that swarms may be better at detecting smells than individuals, since there are more organisms to detect and track the odor. To do this, individuals would have to ‘trust’ their neighbors and follow them for part of the search. Researchers modeled organisms that followed both their own paths (moths) and their neighbors’ flight patterns (bird flocks). They found that a group of robots most efficiently located a source when individuals trusted their neighbors’ senses over their own about 80% of the time.

Biological Model

Moths have sensitive antennae that help them detect the presence of pheromones released by other moths. Wind often affects the pheromone location, causing moths to take indirect, zigzagging paths to their destinations, usually by heading upwind of the most recent pheromone smell they encountered.

Birds such as starlings fly together in large groups of hundreds or thousands of individuals. They manage to stay within inches of other starlings, turning at high speeds, without ever colliding. They do this by paying close attention to the speed and direction of the seven other starlings closest to it. Any fewer, and there’s not enough reliable information for a starling to maintain flying with precision within the flock. Any more, and there’s too much information to process quickly and make real-time decisions.

See Related Content

flock of black birds flying across green grass and blue sky

Biological Strategy

Starlings Coordinate Movements Within a Flock

European starling

Starlings stay together within a flock by paying attention to the movements of the seven other birds closest to it

a brown moth with large antennae sits on a grass stem against a grassy background and blue sky

Biological Strategy

Moths Make Sense of Barely-There Scents

Moths

Moth antennae sense specific airborne molecules in minute concentrations.

References

Journal article

Collective olfactory search in a turbulent environment

Physical Review E

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