| 1. |
- Kish, Eszter A., et al.
(författare)
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Lognormal distribution of firing time and rate from a single neuron?
- 2015
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Ingår i: Cognitive Neurodynamics. - : Springer Science and Business Media LLC. - 1871-4080 .- 1871-4099. ; 9:4, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- Even a single neuron may be able to produce significant lognormal features in its firing statistics due to noise in the charging ion current. A mathematical scheme introduced in advanced nanotechnology is relevant for the analysis of this mechanism in the simplest case, the integrate-and-fire model with white noise in the charging ion current.
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| 2. |
- Kish, Lazar L, et al.
(författare)
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Log-normal distribution of single molecule fluorescence bursts in micro/nano-fluidic channels
- 2011
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 99:14, s. 143121-
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Tidskriftsartikel (refereegranskat)abstract
- The width and shape of photon burst histograms pose significant limitations to the identification of single molecules in micro/nano-fluidic channels, and the nature of these histograms is not fully understood, To reach a deeper understanding, we performed computer simulations based on a Gaussian beam intensity profile with various fluidic channel diameters and assuming (1) a deterministic (noise-free) case, (2) photon emission/absorption noise, and (3) photon noise with diffusion. Photon noise in narrow channels yields a Gaussian burst distribution while additional strong diffusion produces skewed histograms. We use the fluctuating residence time picture Soderlund et al., Phys. Rev, Lett, 80, 2386 (1998)1 and conclude that the skewness of the photon number distribution is caused by the longitudinal diffusive component of the motion of the molecules as they traverse the laser beam. In the case of strong diffusion in narrow channels, this effect leads to a log-normal distribution. We show that the same effect can transform the separate peaks of the photon burst histograms of multiple molecule mixtures into a single log-normal shape.
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| 3. |
- Kish, Lazar L., et al.
(författare)
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Optimum drift velocity for single molecule fluorescence bursts in micro/nano-fluidic channels
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 101:4, s. 043120-
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Tidskriftsartikel (refereegranskat)abstract
- Photonic burst histograms can be used to identify single protein molecules in micro/nano-fluidic channels provided the width of the histogram is narrow. Photonic shot noise and residence time fluctuations, caused by longitudinal diffusion, are the major sources of the histogram width. This paper is a sequel to an earlier one of ours [L. L. Kish et al., Appl. Phys. Lett. 99, 143121 (2011)] and demonstrates that, for a given diffusion coefficient, an increase of the drift velocity enhances the relative shot noise and decreases the relative residence time fluctuations. This leads to an optimum drift velocity that minimizes the histogram width and maximizes the ability to identify single molecules, which is an important result for applications.
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| 4. |
- Aroutiounian, Vladimir M., et al.
(författare)
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Noise spectroscopy of gas sensors
- 2008
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:5-6, s. 786-790
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Tidskriftsartikel (refereegranskat)abstract
- We study current-voltages and low-frequency noise characteristics of the metal-porous silicon-silicon single crystal-metal structure with 50% and 73% porosity of porous silicon. The study is performed in dry air and in a mix of dry air with carbon monoxide of different concentrations. The Hooge noise parameter alpha(H) and the parameter gamma in the frequency dependence of the noise voltage spectral density S-U (f) were determined from experimental data. High sensitivity of spectral dependence of noise to gas concentration allows offering powerful method for determination of gas concentration in the air or environment.
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| 5. |
- Chen, Hsien-Pu, et al.
(författare)
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Do Electromagnetic Waves Exist in a Short Cable at Low Frequencies? : What Does Physics Say?
- 2014
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Ingår i: Fluctuation and Noise Letters. - 0219-4775 .- 1793-6780. ; 13:2, s. 1450016-
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Tidskriftsartikel (refereegranskat)abstract
- We refute a physical model, recently proposed by Gunn, Allison and Abbott (GAA) [http://arxiv.org/pdf/1402.2709v2.pdf], to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN) secure key distribution. Their model, and its theoretical underpinnings, is found to be fundamentally flawed because their assumption of electromagnetic waves violates not only the wave equation but also the second law of thermodynamics, the principle of detailed balance, Boltzmann's energy equipartition theorem, and Planck's formula by implying infinitely strong blackbody radiation. We deduce the correct mathematical model of the GAA scheme, which is based on impedances at the quasi-static limit. Mathematical analysis and simulation results confirm our approach and prove that GAA's experimental interpretation is incorrect too.
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| 6. |
- Chen, Hsien-Pu, et al.
(författare)
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On The "Cracking" Scheme in The Paper "A Directional Coupler Attack Against the Kish Key Distribution System" by Gunn, Allison And Abbott
- 2014
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Ingår i: METROLOGY AND MEASUREMENT SYSTEMS. - : Polish Academy of Sciences Chancellery. - 0860-8229 .- 2300-1941. ; 21:3, s. 389-400
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Tidskriftsartikel (refereegranskat)abstract
- Recently, Gunn, Allison and Abbott (GAA) [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN) secure key distribution. We proved in a former paper [Fluct. Noise Lett. 13 (2014) 1450016] that GAA's mathematical model is unphysical. Here we analyze GAA's cracking scheme and show that, in the case of a loss-free cable, it provides less eavesdropping information than in the earlier (Bergou)-Scheuer-Yariv mean-square-based attack [Kish LB, Scheuer J, Phys. Lett. A 374:2140-2142 (2010)], while it offers no information in the case of a lossy cable. We also investigate GAA's claim to be experimentally capable of distinguishing-using statistics over a few correlation times only-the distributions of two Gaussian noises with a relative variance difference of less than 10(-8). Normally such distinctions would require hundreds of millions of correlations times to be observable. We identify several potential experimental artifacts as results of poor KLJN design, which can lead to GAA's assertions: deterministic currents due to spurious harmonic components caused by ground loops, DC offset, aliasing, non-Gaussian features including non-linearities and other non-idealities in generators, and the time-derivative nature of GAA's scheme which tends to enhance all of these artifacts.
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| 7. |
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| 8. |
- Frenning, Göran, et al.
(författare)
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Spectral analysis of force fluctuations during probe penetration into cohesive powders
- 2008
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910 .- 1873-328X. ; 187:1, s. 62-67
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Tidskriftsartikel (refereegranskat)abstract
- We investigate force fluctuations during probe penetration into cohesive powders consisting of ∼5 μm lactose particles with varying surfaceproperties prepared by spray drying. The results obtained for the more cohesive powders were remarkably similar to those previously reported fororders of magnitude larger noncohesive particles. For the less cohesive powders, the spectral densities were instead found to exhibit two distinctpower-law regions. Furthermore, the spectra were found to be independent of the geometry of the penetrating probe and dimensions of the diecavity. These findings suggest that the response is dominated by particle aggregate or agglomerate movement for the more cohesive powders,whereas the behaviour of the less cohesive ones is consistent with a response dominated by relatively weak force chains, with the fluctuations resulting from the recurring creation and collapse of jammed states being damped for length scales N0.1 mm.
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| 9. |
- Gingl, Zoltan, et al.
(författare)
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Fluctuation-Enhanced Sensing With Zero-Crossing Analysis for High-Speed and Low-Power Applications
- 2010
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10:3, s. 492-497
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Tidskriftsartikel (refereegranskat)abstract
- A new method to generate fingerprints of chemical agents has been introduced in this paper. The method is based on the use of the zero-crossing statistics at fluctuation-enhanced sensing. It is a new version of Ben Kedem's original method based on low-pass filters. To improve computation time and energy efficiency, high-pass filtering is used, and in doing this in the simplest possible way, local zero levels for short-time subwindows are defined and a zero-crossing counting by the use of such windows is carried out. The method turns out to be an effective tool to identify noise processes with different spectra or amplitude distribution, with at least 1000 times less calculation and correspondingly lower energy need than that of the Kedem or the fast Fourier transform methods. We demonstrate the usability of the method by the analysis and recognition of different stochastic processes with similar and different spectra.
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| 10. |
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