| 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
-
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
-
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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| 11. |
- Kish, Laszlo B., et al.
(författare)
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Analysis of an Attenuator Artifact in an Experimental Attack by Gunn-Allison-Abbott Against the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange System
- 2015
-
Ingår i: Fluctuation and Noise Letters. - 0219-4775 .- 1793-6780. ; 14:1, s. 1-8
-
Tidskriftsartikel (refereegranskat)abstract
- A recent paper by Gunn-Allison-Abbott (GAA) [L. J. Gunn et al., Scientific Reports 4 (2014) 6461] argued that the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system could experience a severe information leak. Here we refute their results and demonstrate that GAA's arguments ensue from a serious design flaw in their system. Specifically, an attenuator broke the single Kirchhoff-loop into two coupled loops, which is an incorrect operation since the single loop is essential for the security in the KLJN system, and hence GAA's asserted information leak is trivial. Another consequence is that a fully defended KLJN system would not be able to function due to its builtin current-comparison defense against active (invasive) attacks. In this paper we crack GAA's scheme via an elementary current-comparison attack which yields negligible error probability for Eve even without averaging over the correlation time of the noise.
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| 12. |
- Kish, Laszlo B., et al.
(författare)
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Comments On "A New Transient Attack On The Kish Key Distribution System"
- 2016
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Ingår i: METROLOGY AND MEASUREMENT SYSTEMS. - : Walter de Gruyter GmbH. - 0860-8229 .- 2300-1941. ; 23:3, s. 321-331
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Tidskriftsartikel (refereegranskat)abstract
- A recent IEEE Access Paper by Gunn, Allison and Abbott (GAA) proposed a new transient attack against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system. The attack is valid, but it is easy to build a defense for the KLJN system. Here we note that GAA's paper contains several invalid statements regarding security measures and the continuity of functions in classical physics. These deficiencies are clarified in our present paper, wherein we also emphasize that a new version of the KLJN system is immune against all existing attacks, including the one by GAA.
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| 13. |
- Kish, Laszlo B., et al.
(författare)
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Critical Analysis of the Bennett-Riedel Attack on Secure Cryptographic Key Distributions via the Kirchhoff-Law-Johnson-Noise Scheme
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12, s. e81810-
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Tidskriftsartikel (refereegranskat)abstract
- Recently, Bennett and Riedel (BR) (http://arxiv.org/abs/1303.7435v1) argued that thermodynamics is not essential in the Kirchhoff-law-Johnson-noise (KLJN) classical physical cryptographic exchange method in an effort to disprove the security of the KLJN scheme. They attempted to demonstrate this by introducing a dissipation-free deterministic key exchange method with two batteries and two switches. In the present paper, we first show that BR's scheme is unphysical and that some elements of its assumptions violate basic protocols of secure communication. All our analyses are based on a technically unlimited Eve with infinitely accurate and fast measurements limited only by the laws of physics and statistics. For non-ideal situations and at active (invasive) attacks, the uncertainly principle between measurement duration and statistical errors makes it impossible for Eve to extract the key regardless of the accuracy or speed of her measurements. To show that thermodynamics and noise are essential for the security, we crack the BR system with 100% success via passive attacks, in ten different ways, and demonstrate that the same cracking methods do not function for the KLJN scheme that employs Johnson noise to provide security underpinned by the Second Law of Thermodynamics. We also present a critical analysis of some other claims by BR; for example, we prove that their equations for describing zero security do not apply to the KLJN scheme. Finally we give mathematical security proofs for each BR-attack against the KLJN scheme and conclude that the information theoretic (unconditional) security of the KLJN method has not been successfully challenged.
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| 14. |
- Kish, Laszlo B., et al.
(författare)
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Does Information Have Mass?
- 2013
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Ingår i: Proceedings of the IEEE. - 0018-9219 .- 1558-2256. ; 101:9, s. 1895-1899
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This article addresses the fundamental question of minimum mass related to a bit of information from the angles of quantum physics and special relativity. The results indicate that there are different answers depending on the physical situation, and sometimes the mass can even be negative. It tends to be skeptical about the earlier mass estimations, mentioned above, because the results indicate that the electron's mass does not play a role in any one of them. Finally, in a seemingly related but actually different and independent context of measured inaccuracies of the gravitation constant, it refers to experiments on the weight transient of memory devices after information writing and erasure.
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| 15. |
- Kish, Laszlo B., et al.
(författare)
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Elimination of a Second-Law-Attack, and All Cable-Resistance-Based Attacks, in the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange System
- 2014
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Ingår i: Entropy. - : MDPI AG. - 1099-4300. ; 16:10, s. 5223-5231
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Tidskriftsartikel (refereegranskat)abstract
- We introduce the so far most efficient attack against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system. This attack utilizes the lack of exact thermal equilibrium in practical applications and is based on cable resistance losses and the fact that the Second Law of Thermodynamics cannot provide full security when such losses are present. The new attack does not challenge the unconditional security of the KLJN scheme, but it puts more stringent demands on the security/privacy enhancing protocol than for any earlier attack. In this paper we present a simple defense protocol to fully eliminate this new attack by increasing the noise-temperature at the side of the smaller resistance value over the noise-temperature at the side with the greater resistance. It is shown that this simple protocol totally removes Eve's information not only for the new attack but also for the old Bergou-Scheuer-Yariv attack. The presently most efficient attacks against the KLJN scheme are thereby completely nullified.
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| 16. |
- Kish, Laszlo B., et al.
(författare)
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Enhanced Usage of Keys Obtained by Physical, Unconditionally Secure Distributions
- 2015
-
Ingår i: Fluctuation and Noise Letters. - 0219-4775 .- 1793-6780. ; 14:2, s. 1-3
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Tidskriftsartikel (refereegranskat)abstract
- Unconditionally secure physical key distribution schemes are very slow, and it is practically impossible to use a one-time-pad based cipher to guarantee unconditional security for the encryption of data because using the key bits more than once gives out statistical information, for example via the known-plain-text-attack or by utilizing known components of the protocol and language statistics. Here, we outline a protocol that reduces this speed problem and allows almost-one-time-pad based communication with an unconditionally secure physical key of finite length. The physical, unconditionally secure key is not used for data encryption but is employed in order to generate and share a new software-based key without any known-plain-text component. The software-only-based key distribution is then changed from computationally secure to unconditionally secure, because the communicated key-exchange data (algorithm parameters, one-way functions of random numbers, etc.) are encrypted in an unconditionally secure way with a one-time-pad. For practical applications, this combined physical/software key distribution based communication looks favorable compared to the software-only and physical-only key distribution based communication whenever the speed of the physical key distribution is much lower than that of the software-based key distribution. A mathematical security proof of this new scheme remains an open problem.
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| 17. |
- Kish, Laszlo B., et al.
(författare)
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Fluctuation-Enhanced Sensing for Biological Agent Detection and Identification
- 2011
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Ingår i: IEEE transactions on nanotechnology. - 1536-125X .- 1941-0085. ; 10:6, s. 1238-1242
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Tidskriftsartikel (refereegranskat)abstract
- We survey and show our earlier results about three different ways of fluctuation-enhanced sensing of bio agent, 1) the phage-based method for bacterium detection published earlier; 2) sensing and evaluating the odors of microbes; and 3) spectral and amplitude distribution analysis of noise in light scattering to identify spores based on their diffusion coefficient.
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| 18. |
- Kish, Laszlo B, et al.
(författare)
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Information, Noise, and Energy Dissipation: : Laws, Limits, and Applications
- 2017
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Ingår i: Molecular Architectonics. - Cham : Springer. - 9783319570952 ; , s. 27-44
-
Bokkapitel (refereegranskat)abstract
- This chapter addresses various subjects, including some open questions related to energy dissipation, information, and noise, that are relevant for nano- and molecular electronics. The object is to give a brief and coherent presentation of the results of a number of recent studies of ours
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| 19. |
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| 20. |
- Kish, Laszlo B., et al.
(författare)
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On the security of the Kirchhoff-law-Johnson-noise (KLJN) communicator
- 2014
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Ingår i: Quantum Information Processing. - : Springer Science and Business Media LLC. - 1570-0755 .- 1573-1332. ; 13:10, s. 2213-2219
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Tidskriftsartikel (refereegranskat)abstract
- A simple and general proof is given for the information theoretic (unconditional) security of the Kirchhoff-law-Johnson-noise key exchange system under practical conditions. The unconditional security for ideal circumstances, which is based on the second law of thermodynamics, is found to prevail even under slightly non-ideal conditions. This security level is guaranteed by the continuity of functions describing classical physical linear, as well as stable non-linear, systems. Even without privacy amplification, Eve's probability for successful bit guessing is found to converge toward 0.5-i.e., the perfect security level-when ideal conditions are approached.
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| 21. |
- Kish, Laszlo B., et al.
(författare)
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Random-Resistor-Random-Temperature Kirchhoff-Law-Johnson-Noise (RRRT-KLJN) Key Exchange
- 2016
-
Ingår i: METROLOGY AND MEASUREMENT SYSTEMS. - : Walter de Gruyter GmbH. - 0860-8229 .- 2300-1941. ; 23:1, s. 3-11
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Tidskriftsartikel (refereegranskat)abstract
- We introduce two new Kirchhoff-law-Johnson-noise (KLJN) secure key distribution schemes which are generalizations of the original KLJN scheme. The first of these, the Random-Resistor (RR-) KLJN scheme, uses random resistors with values chosen from a quasi-continuum set. It is well-known since the creation of the KLJN concept that such a system could work in cryptography, because Alice and Bob can calculate the unknown resistance value from measurements, but the RR-KLJN system has not been addressed in prior publications since it was considered impractical. The reason for discussing it now is the second scheme, the Random Resistor Random Temperature (RRRT-) KLJN key exchange, inspired by a recent paper of Vadai, Mingesz and Gingl, wherein security was shown to be maintained at non-zero power flow. In the RRRT-KLJN secure key exchange scheme, both the resistances and their temperatures are continuum random variables. We prove that the security of the RRRT-KLJN scheme can prevail at a non-zero power flow, and thus the physical law guaranteeing security is not the Second Law of Thermodynamics but the Fluctuation-Dissipation Theorem. Alice and Bob know their own resistances and temperatures and can calculate the resistance and temperature values at the other end of the communication channel from measured voltage, current and power-flow data in the wire. However, Eve cannot determine these values because, for her, there are four unknown quantities while she can set up only three equations. The RRRT-KLJN scheme has several advantages and makes all former attacks on the KLJN scheme invalid or incomplete.
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| 22. |
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| 23. |
- Kish, Laszlo B., et al.
(författare)
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Unconditionally Secure Credit/Debit Card Chip Scheme and Physical Unclonable Function
- 2017
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Ingår i: Fluctuation and Noise Letters. - : WORLD SCIENTIFIC PUBL CO PTE LTD. - 0219-4775 .- 1793-6780. ; 16:1
-
Tidskriftsartikel (refereegranskat)abstract
- The statistical-physics-based Kirchhoff-law-Johnson-noise (KLJN) key exchange offers a new and simple unclonable system for credit/ debit card chip authentication and payment. The key exchange, the authentication and the communication are unconditionally secure so that neither mathematics-nor statistics-based attacks are able to crack the scheme. The ohmic connection and the short wiring lengths between the chips in the card and the terminal constitute an ideal setting for the KLJN protocol, and even its simplest versions offer unprecedented security and privacy for credit/debit card chips and applications of physical unclonable functions (PUFs).
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| 24. |
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| 25. |
- Kish, Laszlo B., et al.
(författare)
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Zero-point term and quantum effects in the Johnson noise of resistors : a critical appraisal
- 2016
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Ingår i: Journal of Statistical Mechanics. - : IOP Publishing. - 1742-5468.
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Tidskriftsartikel (refereegranskat)abstract
- There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor. This term originates from a quantum-theoretical treatment of the fluctuation-dissipation theorem (FDT). Is the zero-point term really there, or is it only an experimental artifact, due to the uncertainty principle, for phase-sensitive amplifiers? Could it be removed by renormalization of theories? We discuss some historical measurement schemes that do not lead to the effect predicted by the FDT, and we analyse new features that emerge when the consequences of the zero-point term are measured via the mean energy and force in a capacitor shunting the resistor. If these measurements verify the existence of a zero-point term in the noise, then two types of perpetual motion machines can be constructed. Further investigation with the same approach shows that, in the quantum limit, the Johnson-Nyquist formula is also invalid under general conditions even though it is valid for a resistor-antenna system. Therefore we conclude that in a satisfactory quantum theory of the Johnson noise, the FDT must, as a minimum, include also the measurement system used to evaluate the observed quantities. Issues concerning the zero-point term may also have implications for phenomena in advanced nanotechnology.
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| 26. |
- Kish, Laszlo B., et al.
(författare)
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Zero Thermal Noise in Resistors at Zero Temperature
- 2016
-
Ingår i: Fluctuation and Noise Letters. - : World Scientific. - 0219-4775 .- 1793-6780. ; 15:3
-
Tidskriftsartikel (refereegranskat)abstract
- The bandwidth of transistors in logic devices approaches the quantum limit, where Johnsonnoise and associated error rates are supposed to be strongly enhanced. However, the related theory — asserting a temperature-independent quantum zero-point (ZP) contribution to Johnson noise, which dominates the quantum regime — is controversial and resolution of the controversy is essential to determine the real error rate and fundamental energy dissipation limits of logic gates in the quantum limit. The Callen–Welton formula (fluctuation–dissipation theorem) of voltage and current noise for a resistance is the sum of Nyquist’s classical Johnson noise equation and a quantum ZP term with a power density spectrum proportional to frequency and independent of temperature. The classical Johnson–Nyquist formula vanishes at the approach of zero temperature, but the quantum ZP term still predicts non-zero noise voltage and current. Here, we show that this noise cannot be reconciled with the Fermi–Dirac distribution, which defines the thermodynamics of electrons according to quantum-statistical physics. Consequently,Johnson noise must be nil at zero temperature, and non-zero noise found for certain experimental arrangements may be a measurement artifact, such as the one mentioned in Kleen’s uncertainty relation argument.
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| 27. |
- Kwan, Chiman, et al.
(författare)
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Advanced agent identification with fluctuation-enhanced sensing
- 2008
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:5-6, s. 706-713
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Tidskriftsartikel (refereegranskat)abstract
- Conventional agent sensing methods normally use the steady state sensor values for agent classification. Many sensing elements (Hines et al., 1999, Ryan et al., 2004, Young et al.,, 2003, Qian et al., 2004, Qian et al.,, 2006, Carmel et ad., 2003) are needed in order to correctly classify multiple agents in mixtures. Fluctuation-enhanced sensing (FES) looks beyond the steady-state values and extracts agent information from spectra and bispectra. As a result, it is possible to use a single sensor to perform multiple agent classification. This paper summarizes the application of some advanced algorithms that can classify and estimate concentrations of different chemical agents. Our tool involves two steps. First, spectral and bispectral features will be extracted from the sensor signals. The features contain unique agent characteristics. Second, the features are fed into a hyperspectral signal processing algorithm for agent, classification and concentration estimation. The basic idea here is to use the spectral/bispectral shape information to perform agent classification. Extensive simulations have been performed by using simulated nanosensor data, as well as actual experimental data using commercial sensor (Taguchi). It was observed that our algorithms are able to accurately classify different agents, and also can estimate the concentration of the agents. Bispectra contain more information than spectra at the expense of high-computational costs. Specific nanostructured sensor model data yielded excellent performance because the agent responses are additive with this type of sensor. Moreover, for measured conventional sensor outputs, our algorithms also showed reasonable performance in terms of agent classification.
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| 28. |
- Lentka, Lukasz, et al.
(författare)
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DETERMINATION OF GAS MIXTURE COMPONENTS USING FLUCTUATION ENHANCED SENSING AND THE LS-SVM REGRESSION ALGORITHM
- 2015
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Ingår i: METROLOGY AND MEASUREMENT SYSTEMS. - : Walter de Gruyter GmbH. - 0860-8229 .- 2300-1941. ; XXII:3, s. 341-350
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Tidskriftsartikel (refereegranskat)abstract
- This paper analyses the effectiveness of determining gas concentrations by using a prototype WO3 resistive gas sensor together with fluctuation enhanced sensing. We have earlier demonstrated that this method can determine the composition of a gas mixture by using only a single sensor. In the present study, we apply Least-Squares Support-Vector-Machine-based (LS-SVM-based) nonlinear regression to determine the gas concentration of each constituent in a mixture. We confirmed that the accuracy of the estimated gas concentration could be significantly improved by applying temperature change and ultraviolet irradiation of the WO3 layer. Fluctuation-enhanced sensing allowed us to predict the concentration of both component gases.
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| 29. |
- Saez, Yessica, et al.
(författare)
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Current and voltage based bit errors and their combined mitigation for the Kirchhoff-law-Johnson-noise secure key exchange
- 2014
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Ingår i: Journal of Computational Electronics. - : Springer Science and Business Media LLC. - 1569-8025 .- 1572-8137. ; 13:1, s. 271-277
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Tidskriftsartikel (refereegranskat)abstract
- We classify and analyze bit errors in the current measurement mode of the Kirchhoff-law-Johnson-noise (KLJN) key distribution. The error probability decays exponentially with increasing bit exchange period and fixed bandwidth, which is similar to the error probability decay in the voltage measurement mode. We also analyze the combination of voltage and current modes for error removal. In this combination method, the error probability is still an exponential function that decays with the duration of the bit exchange period, but it has superior fidelity to the former schemes.
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| 30. |
- Schmera, Gabor, et al.
(författare)
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Separating Chemical Signals of Adsorption-Desorption and Diffusive Processes
- 2010
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10:3, s. 461-464
-
Tidskriftsartikel (refereegranskat)abstract
- We present a new sensor signal processing method that improves selectivity, sensitivity, and processing speed in systems, using fluctuation-enhanced sensing. We consider the output signal of a symmetric two-sensor arrangement and generate two independent output spectra by separating the adsorption-desorption signal component from the diffusion signal component. We demonstrate the key features of our method by computer modeling and simulation.
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| 31. |
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| 32. |
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| 33. |
- Topalian, Zareh, et al.
(författare)
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Resistance noise at the metal-insulator transition in thermochromic VO2 films
- 2015
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 117:2, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Thermochromic VO2 films were prepared by reactive DC magnetron sputtering onto heated sapphire substrates and were used to make 100-nm-thick samples that were 10 lm wide and 100 lm long. The resistance of these samples changed by a factor similar to 2000 in the 50T-c. These exponents can be reconciled with the Pennetta-Trefan-Reggiani theory [Pennetta et al., Phys. Rev. Lett. 85, 5238 (2000)] for lattice percolation with switching disorder ensuing from random defect generation and healing in steady state. Our work hence highlights the dynamic features of the percolating semiconducting and metallic-like regions around T-c in thermochromic VO2 films. (C) 2015 AIP Publishing LLC.
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| 34. |
- Trawka, Maciej Pawel, et al.
(författare)
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UV-Light-Induced Fluctuation Enhanced Sensing by WO3-Based Gas Sensors
- 2016
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 16:13, s. 5152-5159
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Tidskriftsartikel (refereegranskat)abstract
- WO3-based gas sensors were investigated under UV-light irradiation and at different working temperatures with the object of achieving superior sensitivity and selectivity. Resistance fluctuations in the WO3 layer were studied together with dc resistance measurements. The data were taken in synthetic air, ethanol, nitrogen dioxide, and mixtures of these gases. We conclude that UV irradiation can easily be applied to enhance the gas sensing properties of a WO3 layer.
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