CONTEXT

Animals like insects or birds look for food and other animals by locating odorous sources. Semiconductor sensor detect substances and evaluate their concentration, however such task must take into account the environment like air flow which impact the diffusion characteristics. Chemotactic strategies are based on gradient of concentration measurement but mixing in a flowing medium breaks up regions of high concentration into random and disconnected patches and average concentration may decay rapidly with distance from the source. So a macroscopic searcher must devise a strategy of movement based on sporadic cues and partial information