Acoustic Scene Classification by Enhanced High-Frequency Weak Signal Characteristic Spectrum

2019 ◽  
Author(s):  
Wenjie Hao ◽  
Lasheng Zhao ◽  
Qiang Zhang
Keyword(s):  
High Frequency ◽  
Weak Signal ◽  
Scene Classification ◽  
Signal Characteristic ◽  
Characteristic Spectrum

An improved adaptive stochastic resonance with general scale transformation to extract high-frequency characteristics in strong noise

2018 ◽  
Vol 32 (15) ◽  
pp. 1850185 ◽  
Author(s):  
Dawen Huang ◽  
Jianhua Yang ◽  
Jingling Zhang ◽  
Houguang Liu
Keyword(s):  
Stochastic Resonance ◽  
High Frequency ◽  
Signal To Noise Ratio ◽  
Scale Transformation ◽  
Weak Signal ◽  
Signal Features ◽  
Signal Characteristics ◽  
Periodic Signals ◽  
Sr Method ◽  
General Scale

The idea of general scale transformation is introduced in detail. Based on this idea, an improved adaptive stochastic resonance (SR) method is proposed to extract weak signal features. Different periodic signals are considered to verify the proposed method. Compared with the normalized scale transformation, the output signal-to-noise ratio (SNR) of the proposed method is increased to a greater extent. Further, the influences of some key parameters on the responses of the two methods are discussed minutely. Results show that the improved adaptive SR method with general scale transformation is obviously superior to the traditional normalized scale transformation that is used in the former literatures. For different noise intensities and time scales, the proposed approach can always obtain the optimal response of SR to enhance the weak signal characteristics.

Application with Wavelet Detection to Signal Process of SINS

2012 ◽  
Vol 571 ◽  
pp. 671-675
Author(s):  
Xiang Yuan Huang ◽  
Xia Qing Tang ◽  
Li Bi Guo ◽  
Xu Wei Cheng
Keyword(s):  
High Frequency ◽  
Simulation Experiment ◽  
Detection Method ◽  
Low Frequency ◽  
Frequency Noise ◽  
Wavelet Filter ◽  
Initial Alignment ◽  
Signal Process ◽  
Signal Characteristic ◽  
Alignment Process

Aimed at disturbance caused from motor running and personnel ambulation during initial alignment process of SINS, a new signal detection method of disturbance based on wavelet analysis is brought out. Through analyzing original signal characteristic of FOG and the data with wavelet filter on disturbance base, finds out wavelet filter just have effectiveness to high frequency noise. Then T&L signal detecting law is introduced, and builds T&L signal with high frequency part of wavelet decomposing to estimates interfere time and then resample. Offline simulation experiment results indicate the method can eliminate low frequency disturbance effectively and has certain apply value.

scholarly journals Evaluating the dendroclimatological potential of blue intensity on multiple conifer species from Australasia

2021 ◽  
Author(s):  
Rob Wilson ◽  
Kathy Allen ◽  
Patrick Baker ◽  
Sarah Blake ◽  
Gretel Boswijk ◽  
...  
Keyword(s):  
New Zealand ◽  
Tree Ring ◽  
High Frequency ◽  
Ring Width ◽  
Signal Strength ◽  
Summer Temperature ◽  
Weak Signal ◽  
Conifer Species ◽  
Blue Intensity ◽  
Blue Reflectance

Abstract. We evaluate a range of blue intensity (BI) tree-ring parameters in eight conifer species (12 sites) from Tasmania and New Zealand for their dendroclimatic potential, and as surrogate wood anatomical proxies. Using a dataset of ca. 10–15 trees per site, we measured earlywood maximum blue reflectance intensity (EWB), latewood minimum blue reflectance intensity (LWB) and the associated delta blue intensity (DB) parameter for dendrochronological analysis. No resin extraction was performed, impacting low frequency trends. Therefore, we focused only on the high frequency signal by detrending all tree-ring and climate data using a 20-year cubic smoothing spline. All BI parameters express low relative variance and weak signal strength compared to ring-width. Correlation analysis and principal component regression experiments identified a weak and variable climate response for most ring-width chronologies. However, for most sites, the EWB data, despite weak signal strength, expressed strong calibrations with summer temperatures. Significant correlations for LWB were also noted, but the sign of the relationship for most species is opposite to that reported for all conifer species in the Northern Hemisphere. DB performed well for the Tasmanian sites but explained minimal temperature variance in New Zealand. Using the full multi-species/parameter network, excellent summer temperature calibration was identified for both Tasmania and New Zealand ranging from 52 % to 78 % explained variance, with equally robust independent validation (Coefficient of Efficiency = 0.41 to 0.77). Comparison of the Tasmanian BI reconstruction with a wood anatomical reconstruction shows that these parameters record essentially the same strong high frequency summer temperature signal. Despite these excellent results, a substantial challenge exists with the capture of potential secular scale climate trends. Although DB, band-pass and other signal processing methods may help with this issue, substantially more experimentation is needed in conjunction with comparative analysis with ring density and quantitative WA measurements.

Enhancing the Weak Signal With Arbitrary High-Frequency by Vibrational Resonance in Fractional-Order Duffing Oscillators

2017 ◽  
Vol 12 (5) ◽  
Author(s):  
J. H. Yang ◽  
Miguel A. F. Sanjuán ◽  
H. G. Liu
Keyword(s):  
Fractional Order ◽  
High Frequency ◽  
Low Frequency ◽  
Original System ◽  
Scale Transformation ◽  
Weak Signal ◽  
Vibrational Resonance ◽  
High Frequency Signal ◽  
System A ◽  
Auxiliary Signal

When the traditional vibrational resonance (VR) occurs in a nonlinear system, a weak character signal is enhanced by an appropriate high-frequency auxiliary signal. Here, for the harmonic character signal case, the frequency of the character signal is usually smaller than 1 rad/s. The frequency of the auxiliary signal is dozens of times of the frequency of the character signal. Moreover, in the real world, the characteristic information is usually indicated by a weak signal with a frequency in the range from several to thousands rad/s. For this case, the weak high-frequency signal cannot be enhanced by the traditional mechanism of VR, and as such, the application of VR in the engineering field could be restricted. In this work, by introducing a scale transformation, we transform high-frequency excitations in the original system to low-frequency excitations in a rescaled system. Then, we make VR to occur at the low frequency in the rescaled system, as usual. Meanwhile, the VR also occurs at the frequency of the character signal in the original system. As a result, the weak character signal with arbitrary high-frequency can be enhanced. To make the rescaled system in a general form, the VR is investigated in fractional-order Duffing oscillators. The form of the potential function, the fractional order, and the reduction scale are important factors for the strength of VR.

scholarly journals FENOMENA SPORADIC E FREKUENSI 5.2 MHZ PADA KONDISI SOLAR MINIMUM TAHUN 2019

2020 ◽  
Vol 7 (2) ◽  
pp. 116
Author(s):  
Zulmi Zakariyah ◽  
Titon Dutono ◽  
Tri Budi Santoso ◽  
Bustamir Arif
Keyword(s):  
High Frequency ◽  
Solar Minimum ◽  
Data Retrieval ◽  
Signal Propagation ◽  
Propagation Path ◽  
Weak Signal ◽  
Radio Stations ◽  
Observation Process ◽  
Sporadic E ◽  
Hf Wave

<p><em>High Frequency (HF) Communication is very dependent on the condition of the ionosphere which changes conditions over time. 2019 is a year with minimum solar conditions marked by a lack of solar cold spots. This condition can cause interference with the propagation path of radio waves in the ionosphere. In this research, a report on HF wave propagation observations is presented using a retrospective method to determine the sporadic E intensity at minimum solar conditions. Data retrieval is done by beacon / sounding system between radio stations by using a low power signal processing software that is Weak Signal Propagation Report (WSPR). Observations were made by building 2 radio stations in Surabaya (7.30S, 112.78E) as transmitter and radio stations in Jombang (7.61S, 112.31E) as receiver. Observations were carried out for one year from November 2018 until October 2019. During the observation process, a frequency of 5.2 MHz </em><em>is</em><em> used and the results showed that there were several days that described a favorable phenomenon for HF communication at close range (below 500 km), namely Sporadic E. During the observation it was obtained 8 times the Sporadic E phenomenon that is quite long with a time span of occurrence between 1 hour to 3 hours. Overall observations show that in May to August is the time when most Sporadic E phenomena occur. So from this </em><em>research,</em><em> it can be concluded that the sporadic E phenomenon can still occur when the sun enters the minimum solar conditions.</em></p><p><em><strong>Keywords</strong></em><em>: </em><em>HF, Solar Minimum, Ionospher, Sporadic E</em><strong><em> </em></strong></p><p><em>Komunikasi High Frequency (HF) sangat bergantung pada kondisi ionosfer yang mengalami perubahan kondisi dari waktu ke waktu. Tahun 2019 merupakan tahun dengan kondisi solar minimum yang ditandai dengan minimnya nilai titik dingin matahari. Kondisi ini dapat mengakibatkan gangguan pada jalur propagasi gelombang radio di lapisan ionosfer. Pada penelitian ini, disajikan laporan pengamatan propagasi gelombang HF menggunakan metode retrospektif untuk mengetahui intensitas sporadic E saat kondisi solar minimum. Pengambilan data dilakukan dengan sistem beacon / sounding antar stasiun radio dengan memanfaatkan software pengolahan sinyal daya rendah yaitu Weak Signal Propagation Report (WSPR). Pengamatan dilakukan dengan membangun 2 stasiun radio yang berada di Surabaya (7.30S, 112.78E) sebagai pemancar dan stasiun radio di Jombang (7.61S, 112.31E) sebagai penerima. Pengamatan dilakukan selama satu tahun dari bulan November 2018 sampai dengan bulan Oktober 2019. Pada proses pengamatan digunakan frekuensi 5.2 MHz dan hasilnya menunjukkan terdapat beberapa hari yang menggambarkan fenomena menguntungkan untuk komunikasi HF jarak dekat (dibawah 500 km) yaitu Sporadic E. Selama pengamatan telah didapatkan 8 kali fenomena Sporadic E yang cukup lama dengan rentang waktu kejadian antara 1 jam hingga 3 jam. Secara keseluruhan hasil pengamatan menunjukkan bahwa pada bulan Mei hingga bulan Agustus merupakan waktu paling banyak terjadinya fenomena Sporadic E. Sehingga dari penelitian ini dapat disimpulkan bahwa fenomena sporadic E masih bisa terjadi ketika matahari memasuki kondisi solar minimum.</em></p><p><em><strong>Kata kunci</strong></em><em>: </em><em>HF, Solar Minimum, Ionosfer, Sporadic E</em></p>

scholarly journals Vibrational resonance in a neuron–astrocyte coupled model

2021 ◽  
Vol 379 (2198) ◽  
Author(s):  
Ali Calim ◽  
Andre Longtin ◽  
Muhammet Uzuntarla
Keyword(s):  
High Frequency ◽  
Resonance Effect ◽  
Coupled Model ◽  
Underlying Mechanism ◽  
Weak Signal ◽  
Weak Signal Detection ◽  
Theme Issue ◽  
Vibrational Resonance ◽  
Key Factor ◽  
And Control

Recent findings have revealed that not only neurons but also astrocytes, a special type of glial cells, are major players of neuronal information processing. It is now widely accepted that they contribute to the regulation of their microenvironment by cross-talking with neurons via gliotransmitters. In this context, we here study the phenomenon of vibrational resonance in neurons by considering their interaction with astrocytes. Our analysis of a neuron–astrocyte pair reveals that intracellular dynamics of astrocytes can induce a double vibrational resonance effect in the weak signal detection performance of a neuron, exhibiting two distinct wells centred at different high-frequency driving amplitudes. We also identify the underlying mechanism of this behaviour, showing that the interaction of widely separated time scales of neurons, astrocytes and driving signals is the key factor for the emergence and control of double vibrational resonance. This article is part of the theme issue ‘Vibrational and stochastic resonance in driven nonlinear systems (part 2)’.

scholarly journals Evaluating the dendroclimatological potential of blue intensity on multiple conifer species from Tasmania and New Zealand

2021 ◽  
Vol 18 (24) ◽  
pp. 6393-6421
Author(s):  
Rob Wilson ◽  
Kathy Allen ◽  
Patrick Baker ◽  
Gretel Boswijk ◽  
Brendan Buckley ◽  
...  
Keyword(s):  
New Zealand ◽  
High Frequency ◽  
Ring Width ◽  
Principal Component Regression ◽  
Principal Component ◽  
Signal Strength ◽  
Summer Temperature ◽  
Weak Signal ◽  
Conifer Species ◽  
Blue Intensity

Abstract. We evaluate a range of blue intensity (BI) tree-ring parameters in eight conifer species (12 sites) from Tasmania and New Zealand for their dendroclimatic potential, and as surrogate wood anatomical proxies. Using a dataset of ca. 10–15 trees per site, we measured earlywood maximum blue intensity (EWB), latewood minimum blue intensity (LWB), and the associated delta blue intensity (DB) parameter for dendrochronological analysis. No resin extraction was performed, impacting low-frequency trends. Therefore, we focused only on the high-frequency signal by detrending all tree-ring and climate data using a 20-year cubic smoothing spline. All BI parameters express low relative variance and weak signal strength compared to ring width. Correlation analysis and principal component regression experiments identified a weak and variable climate response for most ring-width chronologies. However, for most sites, the EWB data, despite weak signal strength, expressed strong coherence with summer temperatures. Significant correlations for LWB were also noted, but the sign of the relationship for most species is opposite to that reported for all conifer species in the Northern Hemisphere. DB results were mixed but performed better for the Tasmanian sites when combined through principal component regression methods than for New Zealand. Using the full multi-species/parameter network, excellent summer temperature calibration was identified for both Tasmania and New Zealand ranging from 52 % to 78 % explained variance for split periods (1901–1950/1951–1995), with equally robust independent validation (coefficient of efficiency = 0.41 to 0.77). Comparison of the Tasmanian BI reconstruction with a quantitative wood anatomical (QWA) reconstruction shows that these parameters record essentially the same strong high-frequency summer temperature signal. Despite these excellent results, a substantial challenge exists with the capture of potential secular-scale climate trends. Although DB, band-pass, and other signal processing methods may help with this issue, substantially more experimentation is needed in conjunction with comparative analysis with ring density and QWA measurements.

Sign in / Sign up

Export Citation Format

Share Document