Ternary Fingerprints with Reference Odor for Fluctuation-Enhanced Sensing

Abstract

An improved method for fluctuation-enhanced sensing (FES) is introduced. We enhanced the old binary fingerprinting method, where the fingerprint bit values were ±1, by introducing ternary fingerprint bits utilizing a reference odor. In the ternary method, the fingerprint bit values are −1, 0, and +1, where the 0 value stands for the situation where the slope of the spectrum is identical to that of the reference odor. The application of the reference odor spectrum makes the fingerprint relative to the reference. The ternary nature and the reference feature increase the information entropy of the fingerprints. The method is briefly illustrated by sensing bacterial odor in cow manure isolates.

Flicker Noise in Resistive Gas Sensors—Measurement Setups and Applications for Enhanced Gas Sensing

“…Thus, much simpler and more direct approaches have also been tested with good results, for example, the binary [ 97 , 109 ] and ternary [ 11 ] fingerprint methods that extract a bit string from the measured PSD, generating a bit pattern characterizing the chemical agent that can be used as an address that directly calls the name of the chemical agent itself, requiring only a very low energy dissipation.…”

“…We estimate the power spectral density of resistance fluctuations to gather more information about the sensors’ ambient atmosphere. Its intensity and changing slope versus frequency depend on ambient atmosphere composition [ 11 , 12 ]. The main component of the observed 1/f noise uses the Hooge semiempirical formula [ 13 ]: where S I ( f ), S U ( f ), and S R ( f ) are the current, voltage, and resistance spectral densities of the sample polarized by I current, U voltage, and DC resistance R , respectively; N is the number of carriers in the sample; and α H is the Hooge constant representing flicker noise intensity in the studied sample.…”

A Two-Channel DFT Spectrum Analyzer for Fluctuation Enhanced Sensing Based on a PC Audio Board

“…The development of advanced sensing techniques requires the availability of dedicated instrumentation which, not being commercially available, must be custom developed. Among the advanced sensing techniques, the Fluctuation Enhanced Sensing (FES) technique shows great potential as it extends the range of information that can be extracted from a single sensor [ 1 , 2 , 3 , 4 , 5 ]. FES is based on the principle that the stochastic fluctuations of the sensor signal, due to the interactions at the microscopic level between the sensor surface and the agents to detect, are recorded and analyzed rather than its average value.…”

Optimum Choice of Randomly Oriented Carbon Nanotube Networks for UV-Assisted Gas Sensing Applications

“…The sensitivity of the sensors can be further enhanced by utilizing the power spectral density of resistance, current, or voltage fluctuations at low frequencies, where 1/ f noise dominates. ,– Noise is one of the essential parameters of electronic devices, which can limit the sensors’ sensitivity. However, the specific features (e.g., changes in the slope of the noise spectra induced by Lorentzian components), together with resistive responses, can also be used as sensing parameters. , …”

“…However, the specific features (e.g., changes in the slope of the noise spectra induced by Lorentzian components), together with resistive responses, can also be used as sensing parameters. 23,24 In several cases, low-frequency fluctuations are more sensitive to gas molecules than the DC resistance of the device itself. Various reports demonstrated low-frequency noise measurements to examine the response characteristics of the sensors.…”