Stigmergy

Stigmergy is a concept used to describe a particular form of coordination of communication in a decentralized system which includes a large number of individuals. The individuals of the system do not communicate directly, but only indirectly with one another by modifying their local environment. The jointly started is as it were the trigger (see emergence) of follow-up activities and for general instructions for how to proceed with its creation.

Differences is the sematektonische of the marker-based stigmergy. When sematektonischen stigmergy, the current state of the task performance ( for example, the status and characteristics of the nest building ) influences the behavior of the communicating individuals; in the marker-based stigmergy it, however, are task-independent markers (for example, odor and other chemical messengers ) that were placed in the environment.

The term is derived from the Greek words stigma ( στιγμα ) for marking and Ergon ( εργον ) for work.

Principle of operation

The principle is based on that set out in an ambient track stimulates the execution of the next activity - by the same or other parties. In this way, each subsequent activities tend to reinforce and build on each other, leading to spontaneous emergence of coherent and apparently systematic activity. Stigmergy is a form of self-organization. It produces complex, possibly intelligent structures, without any need for planning, control, or even direct communication between the parties.

Stigmergy in nature

Stigmergy was first observed in nature. For example, ants communicate indirectly with each other in the search for food by leaving along its streets Pheromones: An ant colony is thus a stigmergisches system.

Another example are the hills that are built by termites. These insects communicate when building their highly complex structures are also using pheromones: Each animal has a humid soil particles from the environment brought about, provides the particles with pheromones and places it in the shared building. Termites are attracted to the pheromones from conspecifics their colony, and it is therefore in a higher degree likely that they will be placing their soil particles near a location at which other termites that have left her. This leads eventually saw columns, arches, tunnels and chambers are built. However, markers can become obsolete, diffuse, evaporate, etc., so that does not always produce an effective coordinated approach.

Stigmergy in technical systems

Stigmergy has its place on the Internet where many users (agents) communicate with one another by modifying their common virtual environment ( commons- based peer production ). A direct message exchange would thereby dysfunctional. Instead, messages are stored locally and retrieved by the agents involved, their next actions they determine. However, the locally stored information may become out of date. So is not always an optimal solution is guaranteed.

Another possible application is the optimization of transport routes in logistics. This could eg transport vehicles put markers (eg Infochemicals ) visited on them stations. The property of the marker, to diffuse or evaporate may be used technically targeted.

Historical Background

The term stigmergy was introduced in 1959 by the French biologist Pierre -Paul Grasse with respect to the behavior of termites. He defined it as: stimulation of workers through the light they created things. Stigmergy was later also used in experimental research related to automation, multi-agent systems, swarm intelligence and communication in computer networks.