Fluctuation-Enhanced Sensing
Encyclopedia
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
.
utilizing chemical sensors in FES mode, and the related mathematical analysis with experimental demonstration, were carried out only in 1999 by Laszlo B. Kish
, Robert Vajtai and C.G. Granqvist
at Uppsala University
. The name "fluctuation-enhanced sensing" was created by John Audia (United States Navy
), in 2001, after learning about the published scheme.
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 "sensing of phage-triggered ion cascades (SEPTIC)
" method in liquid phase.
In the period of 2006–2009 Signal Processing Inc (Chiman Kwan) developed a portable FES device in collaboration with Texas A&M University
(Laszlo B. Kish) and University of Szeged
(Zoltan Gingl and Peter Heszler
). Efforts to explore higher-order statistics
for FES purposes were led by Janusz Smulko. SPAWAR (United States Navy
) related FES projects were led by Gabor Schmera (see the US Navy
patent site below).
Noise (electronics)
Electronic noise is a random fluctuation in an electrical signal, a characteristic of all electronic circuits. Noise generated by electronic devices varies greatly, as it can be produced by several different effects...
, 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
Noise (electronics)
Electronic noise is a random fluctuation in an electrical signal, a characteristic of all electronic circuits. Noise generated by electronic devices varies greatly, as it can be produced by several different effects...
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
Higher-order statistics
Higher-order statistics are descriptive measures of, among other things, qualities of probability distributions and sample distributions, and are, themselves, extensions of first- and second-order measures to higher orders. Skewness and kurtosis are examples of this...
.
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 noseElectronic nose
An electronic nose is a device intended to detect odors or flavors.Over the last decade, “electronic sensing” or “e-sensing” technologies have undergone important developments from a technical and commercial point of view...
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 B. Kish
László Bela Kish is a physicist and professor of Electrical and Computer Engineering at Texas A&M University. His activities include a wide range of issues surrounding the physics and technical applications of stochastic fluctuations in physical, biological and technological systems, including...
, Robert Vajtai and C.G. Granqvist
Claes-Göran Granqvist
Claes-Göran Granqvist was born in Helsingborg, Sweden, in 1946. He is one of the leading figures of Swedish and international science in various fields including nanomaterials; green nanotechnology; materials for solar energy utilization and energy efficiency , electrochromic materials...
at Uppsala University
Uppsala University
Uppsala University is a research university in Uppsala, Sweden, and is the oldest university in Scandinavia, founded in 1477. It consistently ranks among the best universities in Northern Europe in international rankings and is generally considered one of the most prestigious institutions of...
. The name "fluctuation-enhanced sensing" was created by John Audia (United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
), in 2001, after learning about the published scheme.
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 "sensing of phage-triggered ion cascades (SEPTIC)
Sensing of phage-triggered ion cascades (SEPTIC)
Sensing of phage-triggered ion cascades is a bacterium identification method based on fluctuation-enhanced sensing in fluid medium. The advantages of SEPTIC are the specificity and speed offered by the characteristics of phage infection, the sensitivity due to fluctuation-enhanced sensing, and...
" method in liquid phase.
In the period of 2006–2009 Signal Processing Inc (Chiman Kwan) developed a portable FES device in collaboration with Texas A&M University
Texas A&M University
Texas A&M University is a coeducational public research university located in College Station, Texas . It is the flagship institution of the Texas A&M University System. The sixth-largest university in the United States, A&M's enrollment for Fall 2011 was over 50,000 for the first time in school...
(Laszlo B. Kish) and University of Szeged
University of Szeged
The University of Szeged is one of Hungary's most distinguished universities, and is among the most prominent higher education institutions in Central Europe...
(Zoltan Gingl and Peter Heszler
Peter Heszler
Peter Heszler was a Hungarian physicist. He is well known for, among others, his research on laser-assisted nanoparticle synthesis...
). Efforts to explore higher-order statistics
Higher-order statistics
Higher-order statistics are descriptive measures of, among other things, qualities of probability distributions and sample distributions, and are, themselves, extensions of first- and second-order measures to higher orders. Skewness and kurtosis are examples of this...
for FES purposes were led by Janusz Smulko. SPAWAR (United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
) related FES projects were led by Gabor Schmera (see the US Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
patent site below).