Fluctuation-enhanced sensing (FES) is a specific type of chemical or biological sensing where the stochastic component, ''noise'', of the sensor signal is analyzed. The stages following the sensor in a FES system typically contain filters and preamplifier(s) to extract and amplify the stochastic signal components, which are usually microscopic temporal fluctuations that are orders of magnitude weaker than the sensor signal. Then selected statistical properties of the amplified ''noise'' are analyzed, and a corresponding pattern is generated as the stochastic fingerprint of the sensed agent. Often the power density spectrum of the stochastic signal is used as output pattern however FES has been proven effective with more advanced methods, too, such as

higher-order statistics In statistics, the term higher-order statistics (HOS) refers to functions which use the third or higher power of a sample, as opposed to more conventional techniques of lower-order statistics, which use constant, linear, and quadratic terms (zero ...

History

During the 1990s, several authors (for example, Bruno Neri and coworkers, Peter Gottwald and Bela Szentpali) had proposed using the spectrum of measured noise to obtain information about ambient chemical conditions. However, the first systematic proposal for a generic

electronic nose An electronic nose is an electronic sensing device intended to detect odors or flavors. The expression "electronic sensing" refers to the capability of reproducing human senses using sensor arrays and pattern recognition systems. Since 1982, rese ...

utilizing chemical sensors in FES mode, and the related mathematical analysis with experimental demonstration, were carried out only in 1999 by

Laszlo B. Kish Laszlo Bela Kish (born László Béla Kiss) is a physicist and professor of Electrical Engineering, Electrical and Computer Engineering at Texas A&M University. His activities include a wide range of issues surrounding the physics and technical ...

, Robert Vajtai and C.G. Granqvist at

Uppsala University Uppsala University ( sv, Uppsala universitet) is a public research university in Uppsala, Sweden. Founded in 1477, it is the oldest university in Sweden and the Nordic countries still in operation. The university rose to significance durin ...

. The name "fluctuation-enhanced sensing" was created by John Audia (

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

), in 2001, after learning about the published scheme. In 2003, Alexander Vidybida fro
Bogolyubov Institute for Theoretical Physics
of the National Academy of Sciences of Ukraine has proven mathematically that adsorption–desorption fluctuations during odor primary reception can be used for improving selectivity. During the years, FES has been developed and demonstrated in many studies with various types of sensors and agents in chemical and biological systems. Bacteria have also been detected and identified by FES, either by their odor in air, or by the " SEPTIC" method in liquid phase. In the period of 2006–200
Signal Processing Inc
(Chiman Kwan) developed a portable FES device in collaboration with

Texas A&M University Texas A&M University (Texas A&M, A&M, or TAMU) is a public, land-grant, research university in College Station, Texas. It was founded in 1876 and became the flagship institution of the Texas A&M University System in 1948. As of late 2021, T ...

(Laszlo B. Kish) and

University of Szeged , mottoeng = Truth. Bravery. Freedom. , established = , type = Public research university , founder = Emperor Franz Joseph I , affiliation = European University Association, Science Without Borders, Confucius Institute , budget = US$220 m ...

(Zoltan Gingl and Peter Heszler). Efforts to explore

for FES purposes were led by

Janusz Smulko Janusz Smulko (born April 25, 1964 in Kolno, Poland) is a Polish electronics engineer, full professor of Gdańsk University of Technology. Research Interests: reliability assessment of electronic devices (electrochromic materials, supercapacit ...

. SPAWAR (

) related FES projects were led by Gabor Schmera (see the

US Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

patent site below).

References

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External links

FES website at Texas A&M University.

Summary of three FES-related patents on the US Navy website.
Biological techniques and tools Laboratory equipment Olfaction