Interaction of noise with excitable dynamics

2007 ◽  
Vol 366 (1864) ◽  
pp. 369-380 ◽  
Author(s):  
Gerardo J.Escalera Santos ◽  
M Rivera ◽  
J Escalona ◽  
P Parmananda
Keyword(s):  
Nonlinear Dynamics ◽  
Stochastic Resonance ◽  
Electrochemical Noise ◽  
Electrochemical Cell ◽  
Internal Noise ◽  
External Noise ◽  
Chloride Ions ◽  
System Response ◽  
Noise Sources

In this paper, the interaction of noise with excitable dynamics of a three-electrode electrochemical cell is examined. Different scenarios involving both external and internal noise sources are considered. In the case of external noise, aperiodic stochastic resonance and regulation of the noise-induced spiking behaviour are investigated. In the case of internal noise, the interaction of intrinsic electrochemical noise with autonomous nonlinear dynamics is studied. The amplitude of this internal noise, determined by the concentration of chloride ions, is monotonically increased and the provoked dynamics are analysed. Our results indicate that internal noise, similar to its external counterpart, is able to induce regularity in the system response.

WATERMARK DETECTION USING DYNAMIC STOCHASTIC RESONANCE

2013 ◽  
Vol 12 (03) ◽  
pp. 1350010 ◽  
Author(s):  
RAJIB KUMAR JHA ◽  
APOORV CHATURVEDI ◽  
RAJLAXMI CHOUHAN
Keyword(s):  
Stochastic Resonance ◽  
Spread Spectrum ◽  
Internal Noise ◽  
External Noise ◽  
Detection Technique ◽  
Discrete Wavelet ◽  
Detection Techniques ◽  
Dynamic Stochastic Resonance ◽  
Watermark Embedding ◽  
Dynamic Stochastic

In this paper, a dynamic stochastic resonance (DSR) based watermark detection technique in discrete wavelet transform (DWT) domain is presented. Pseudo random bit sequence having certain seed value is considered as a watermark. Watermark embedding is done by embedding random bits in spread-spectrum fashion to the significant DWT coefficients. Watermark detection is quantitatively characterized by the value of correlation. The performance of watermark detection is improved by DSR which is an iterative process that utilizes the internal noise present in the image or external noise which is added during attacks. Even under various noise attacks, geometrical distortions, image enhancement and compression attacks, the DSR-based random bits detection is observed to give noteworthy improvement over existing watermark detection techniques. DSR-based technique is also found to give better detection performance when compared with the suprathreshold stochastic resonance-based detection technique.

scholarly journals Acoustical Evaluation of Six ‘Green’ Office Buildings

2008 ◽  
Vol 3 (4) ◽  
pp. 108-118 ◽  
Author(s):  
Murray Hodgson
Keyword(s):  
Speech Intelligibility ◽  
Sound Absorption ◽  
Internal Noise ◽  
External Noise ◽  
Office Buildings ◽  
Performance Criteria ◽  
Noise Levels ◽  
Noise Sources ◽  
Design Decisions ◽  
Speech Intelligibility Index

To explain the reactions of the building occupants to their acoustical environments, meetings with the designers, walk-through surveys, and detailed acoustical measurements were done. The objective was to determine how design decisions affect office acoustical environments, and how to improve the acoustical design of ‘green’ office buildings. Design-performance criteria were established. Measurements were made of noise level, reverberation time, speech-intelligibility index (SII), and noise isolation. Noise levels were atypically low in unoccupied buildings with no mechanical ventilation, but excessive in areas near external walls next to noisy external noise sources—especially with windows open for ventilation—and in occupied buildings. Reverberation times were excessive in areas with large volumes and insufficient sound absorption. Speech intelligibility was generally adequate, but speech privacy was inadequate in shared and open-office areas, and into private offices with the doors open for ventilation. Improvement of the acoustical design of ‘green’ buildings must include increasing the external-internal noise isolation and that between workplaces, and the use of adequate sound absorption to control reverberation and noise.

Improving AFM Images with Harmonic Interference by Spectral Analysis

2012 ◽  
Vol 18 (1) ◽  
pp. 186-195
Author(s):  
Marek Kiwilszo ◽  
Artur Zieliński ◽  
Janusz Smulko ◽  
Kazimierz Darowicki
Keyword(s):  
Internal Noise ◽  
External Noise ◽  
Noise Sources ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mode Of Operation ◽  
Nanoscale Imaging ◽  
Harmonic Cancellation ◽  
Scanned Images

AbstractAtomic force microscopy (AFM) is one of the most sensitive tools for nanoscale imaging. As such, it is very sensitive to external noise sources that can affect the quality of collected data. The intensity of the disturbance depends on the noise source and the mode of operation. In some cases, the internal noise from commercial AFM controllers can be significant and difficult to remove. Thus, a new method based on spectrum analysis of the scanned images is proposed to reduce harmonic disturbances. The proposal is a post-processing method and can be applied at any time after measurements. This article includes a few methods of harmonic cancellation (e.g., median filtering, wavelet denoising, Savitzky-Golay smoothing) and compares their effectiveness. The proposed method, based on Fourier transform of the scanned images, was more productive than the other methods mentioned before. The presented data were achieved for images of conductive layers taken in a contact AFM mode.

scholarly journals Duplicate Detection of Spike Events: A Relevant Problem in Human Single-Unit Recordings

2021 ◽  
Vol 11 (6) ◽  
pp. 761
Author(s):  
Gert Dehnen ◽  
Marcel S. Kehl ◽  
Alana Darcher ◽  
Tamara T. Müller ◽  
Jakob H. Macke ◽  
...  
Keyword(s):  
Data Quality ◽  
Single Unit ◽  
Human Subjects ◽  
External Noise ◽  
Hospital Environment ◽  
Noise Sources ◽  
Recording Channels ◽  
Waveform Similarity ◽  
Therapeutic Procedures ◽  
Single Unit Recordings

Single-unit recordings in the brain of behaving human subjects provide a unique opportunity to advance our understanding of neural mechanisms of cognition. These recordings are exclusively performed in medical centers during diagnostic or therapeutic procedures. The presence of medical instruments along with other aspects of the hospital environment limit the control of electrical noise compared to animal laboratory environments. Here, we highlight the problem of an increased occurrence of simultaneous spike events on different recording channels in human single-unit recordings. Most of these simultaneous events were detected in clusters previously labeled as artifacts and showed similar waveforms. These events may result from common external noise sources or from different micro-electrodes recording activity from the same neuron. To address the problem of duplicate recorded events, we introduce an open-source algorithm to identify these artificial spike events based on their synchronicity and waveform similarity. Applying our method to a comprehensive dataset of human single-unit recordings, we demonstrate that our algorithm can substantially increase the data quality of these recordings. Given our findings, we argue that future studies of single-unit activity recorded under noisy conditions should employ algorithms of this kind to improve data quality.

scholarly journals Localization of Increased Noise at Operating Speed of a Passenger Wagon

2021 ◽  
Vol 13 (2) ◽  
pp. 453
Author(s):  
Ján Ďungel ◽  
Peter Zvolenský ◽  
Juraj Grenčík ◽  
Lukáš Leštinský ◽  
Ján Krivda
Keyword(s):  
Natural Frequencies ◽  
Internal Noise ◽  
High Volume ◽  
Acoustic Properties ◽  
Normal Operation ◽  
Mode Shapes ◽  
Railway Transport ◽  
Noise Sources ◽  
Sound Fields ◽  
Real Picture

Noise generated by railway wagons in operation is produced by large numbers of noise sources. Although the railway transport is considered to be environmental friendly, especially in production of CO2 emissions, noise is one of problems that should be solved to keep the railway transport competitive and sustainable in future. In the EU, there is a strong permanent legislation pressure on interior and exterior noise reduction in railway transport. In the last years in Slovakia, besides modernization of existing passenger wagons fleet as a cheaper option of transport quality improvement, quite a number of coaches have been newly manufactured, too. The new design is usually aimed at increased speed, higher travel comfort, in which reduction of noise levels is expected. However, not always the new designs meet all expectations. Noise generation and propagation is a complex system and should be treated such from the beginning. There are possibilities to simulate the structural natural frequencies to predict vibrations and sound generated by these vibrations. However, the real picture about sound fields can be obtained only by practical measurements. Simulations of the wagon’s natural frequencies and mode shapes and measurements in real operation using a digital acoustic camera Soundcam have been done, which showed that for the calculated speeds the largest share of noise from the chassis was not radiated through the floor of the wagon, as was expected, but through the ceiling of the wagon. To improve the acoustic properties of the wagon at higher speed, it was proposed to use high-volume textile insulation in the ceiling of the wagon. The paper briefly presents modern research approaches in the search for ways to reduce internal noise in selected wagons used in normal operation on the Slovak railways.

How does stochastic resonance work within the human brain? – Psychophysics of internal and external noise

2010 ◽  
Vol 375 (2-3) ◽  
pp. 616-624 ◽  
Author(s):  
Takatsugu Aihara ◽  
Keiichi Kitajo ◽  
Daichi Nozaki ◽  
Yoshiharu Yamamoto
Keyword(s):  
Human Brain ◽  
Stochastic Resonance ◽  
External Noise

Acoustic Performance of Louvred Facades for Brisbane Domestic Airport: An Integrated Approach

2012 ◽  
Author(s):  
Frank Butera ◽  
Keith Hewett
Keyword(s):  
Natural Ventilation ◽  
Transmission Loss ◽  
Internal Noise ◽  
Building Design ◽  
Integrated Approach ◽  
External Noise ◽  
Climatic Conditions ◽  
Sustainable Building ◽  
Heating And Cooling ◽  
Airport Terminals

Maximising cross ventilation is a low energy method of naturally ventilating and providing heating and cooling to deep plan spaces. Significant reduction in the emission of greenhouse gases can be achieved through minimising the use of mechanical systems in regions with climatic conditions that support the use of natural ventilation. Arup has provided input into the design of a louvered facade for the control of external noise for Brisbane Domestic Airport. A full scale prototype facade was constructed and noise transmission loss measurements were undertaken. The results indicate that significant noise reduction can be achieved to enable compliance with the internal noise limits for airport terminals, whilst using natural ventilation. The findings from this research will directly benefit building designers and innovators in the pursuit of achieving sustainable building design.

Stochastic Resonance in crayfish hydrodynamic receptors stimulated with external noise

1993 ◽  
Author(s):  
J. K. Douglass ◽  
L. A. Wilkens ◽  
E. Pantazelou ◽  
F. Moss
Keyword(s):  
Stochastic Resonance ◽  
External Noise
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