Novel Applications of Noise in Sensing and Communications

Fluctuation and Noise Letters, 2012

Fluctuation-enhanced sensing (FES) comprises the analysis of the stochastic component of the sensor signal and the utilization of the microscopic dynamics of the interaction between the agent and the sensor. We study the relationship between the measurement time window and the statistical error of the measurement data in the simplest case, when the output is the mean-square value of the stochastic signal. This situation is relevant at any practical case when the time window is finite, for example, when a sampling of the output of a fluctuation-enhanced array takes place; or a single sensor's activation (temperature, etc.) is stepped up; or a single sensor's output is monitored by sampling subsequently in different frequency windows. Our study provides a lower limit of the relative error versus data window size with different types of power density spectra: white noise, 1/f (flicker, pink) noise, and 1/f 2 (red) noise spectra.

Chaos: An Interdisciplinary Journal of Nonlinear …, 2001

—Both selectivity and sensitivity of chemical sensors can be considerably improved by exploiting the information contained in microfluctuations present in the sensor system. We call our collection of methods and algorithms to extract information from these microfluctuations, fluctuation enhanced sensing. In this paper, we present a short survey of results with Taguchi sensors, surface acoustic wave devices, MOSFET-based sensors, and nanosensors.

We present a short survey on fluctuation-enhanced gas sensing. We compare some of its main characteristics with those of classical sensing. We address the problem of linear response, information channel capacity, missed alarms and false alarms.

2003

A short review of our recent research involving the role of noise in a variety of systems is given. Two classes of problems are discussed. The first is the effect of fluctuations on cellular and intercellular calcium oscillations. Oscillations in intracellular calcium ion concetrations are responsible for the regulation of a remarkable number of different cellular processes in the human body. Fluctuation effects taht are ignored in deterministic models of these oscillations are discussed.

Fluctuations or noise have played a changing role in the history of science. Historically, we can identify three views of noise. In the first, up to the end of the 19th century, noise was considered a nuisance to be avoided or eliminated. This is still the implication of the definition of the word noise in any standard dictionary. A second stage dates from the beginning of the 20th century, when it became clear from the study of fluctuations via Onsager relations and fluctuation-dissipation relations that one can obtain useful information about a physical system from its fluctuations. The third stage started about three decades ago, and is marked by the realization that noise can actually play a central role in inducing new phenomena. Examples where noise leads to organized behavior include stochastic resonance, noise-induced phase transitions, noise-induced pattern formation, and noise-induced transport. In this minicourse we sample some such noise-induced phenomena. While many of these fluctuation-induced phenomena involve temporal fluctuations, spatial fluctuations (disorder) can also play a similar organizing role. We briefly illustrate this scenario as well.

IEEE Instrumentation & Measurement Magazine, 2003

M easuring physical constants by examining suitable types of noise has a long history. In 1918, Shottky described two types of noise: thermal noise and shot noise. By the 1920s, measurements of thermal noise had been used to measure the Boltzmann constant, K B , and measurements of shot noise had been used to measure the charge on the electron, e 0 .

Applied Sciences

Fluctuation-enhanced sensing (FES) is a very powerful odor and gas sensing technique and as such it can play a fundamental role in the control of environments and, therefore, in the protection of health. For this reason, we conduct a comprehensive survey on the state-of-the-art of the FES technique, highlighting potentials and limits. Particular attention is paid to the dedicated instrumentation necessary for the application of the FES technique and also in this case limits and possible future developments are highlighted. In particular, we address resolution, measurement speed, reproducibility, memory, noise, and other problems such as the influence of humidity. A number of techniques and guidelines are proposed to overcome these problems. Circuit solutions are also discussed.

2011

We survey and show our earlier results about three different ways of fluctuation-enhanced sensing of bio agent, the phage-based method for bacterium detection published earlier; sensing and evaluating the odors of microbes; and spectral and amplitude distribution analysis of noise in light scattering to identify spores based on their diffusion coefficient.

2006

In systems far from equilibrium, such as cellular biomolecular assemblies, energetic input is converted into systematic execution of function. The functional machinery comprises transport and interconversion of matter, as well as signalling systems and the regulation of other functional components. Within the microscopic dimensions of the cell, these processes are carried out by discrete co-ordinated interactions among molecules in a noisy environment. We take the position that given the pronounced effects noise can have in such small volumes having low copy numbers of molecular species, cells have harnessed evolutionary pressures into making productive use of noise. Correspondingly, given the drive towards miniaturisation in future computational hardware, we can view the attendant concerns about "taming" the noise inherent to this regime as an opportunity to learn from the way cells fulfil their transport and information processing needs. In particular, we shall look at how molecular ratchets exploit thermal noise, how signalling processes may exploit fluctuations in the number of enzymes, and how the ability to read out from conformational substates of enzymes can enable targeted low-pass filtering to guide computational steps through a suitably mapped state space.