Noise Mitigation Methods Research Articles

Acoustic resonant metasurfaces with roughened necks for effective low-frequency sound absorption

The rise in environmental low-frequency noise from human-induced activities due to global urbanization has had a noticeable effect on the health and life quality of urban residents. Despite the implementation of conventional noise mitigation methods, they are only effective within a narrowband frequency range and their efficiency deteriorates when dealing with low-frequency noise. To address the existing problem in noise attenuation, an acoustic resonant metasurface that incorporates sliced Helmholtz-resonator-like substructures with embedded roughened necks is designed to achieve low-frequency sound absorption within a subwavelength scale. The theoretical model of this metasurface is first established, and then parametric studies are conducted to analyze the impact of various geometrical parameters on the sound absorption effect of the proposed metasurface. Subsequently, the sound absorption performance of the proposed design is investigated through numerical and experimental studies using two samples at both single and broadband frequencies. Excellent absorption performances by the samples at a low-frequency spectrum have been achieved. To understand the underlying absorptive mechanism of the proposed metasurface models, theoretical investigations are conducted for acoustic impedance and complex frequency, while numerical studies are also carried out to examine the distribution of acoustic pressure, acoustic velocity and thermoviscous power dissipation density. The research findings presented in this study may facilitate the development of an effective acoustic barrier for low-frequency noise (≤ 200 Hz).

Noise mitigation method for power line communication based on cross-correlation analysis

Abstract Noise has a significant impact on the transmission rate and reliability of power line communication(PLC), which has become a crucial factor affecting PLC. In order to enhance the noise resistance of PLC, this paper proposes a noise mitigation method for PLC based on cross-correlation analysis. Firstly, the characteristics of OFDM signals based on PSK modulation are analyzed. Subsequently, reference signals are created for the purpose of cross-correlation with the PLC signal. Then, the phase of each subcarrier can be obtained. The PLC signal is reconstructed by utilizing the obtained phase, thereby achieving noise mitigation. Finally, the algorithmic program has been written for the simulation of the method in MATLAB. The simulation results show that the noise mitigation method can successfully remove the noise from PLC signals with signal-to-noise ratios within -20dB.

Analyzing VNO Airport Traffic Data of 2023: Specific Aircraft Noise Measurement and Mitigation Recommendations

The expansion of airport operations worldwide yields numerous advantages, yet it also brings about certain adverse consequences, notably noise pollution. In addressing noise pollution, airports deploy a range of noise control strategies, which can be broadly classified into four categories: passive noise mitigation methods, active noise mitigation strategies, regulatory measures, and technological innovations. The paper investigates the feasibility of Balanced Approach (BA) implementation at Vilnius International Airport (VNO according to IATA). In this study, an in depth analysis was conducted on the data pertaining to the frequency of movements, the distinct types, models and age of aircraft that utilized VNO facilities during the calendar year of 2023. Following the analysis conducted throughout 2023, a total of 38 699 aircraft movements were recorded, from which predominant aircraft types were identified: Boeing B737 (A1), Airbus A320 (A2), Airbus A220 (A3), Bombardier CRJ/Challenger (A4), Embraer (A5) and ATR 72-500 (A6). Average age of aircraft most frequently arriving and departing at VNO is 14.35 years. The sound measurements for A1, A3 and A6 were done with Bruel&Kjaer 2270 Investigator sound analyzer. Data then was post processed by BZ-5503 Measurement Partner Suite and measured data Leq, LMAX, different noise levels were compared. Measurements show that permitted noise levels are exceeded, especially by older age aircraft. Reducing air fleet age would be most efficient noise mitigation measure according to BA.

Impulse Noise Mitigation and Channel Estimation Method in OFDM Systems Based on TMSBL

Impulse Noise Mitigation and Channel Estimation Method in OFDM Systems Based on TMSBL

Extracting quantum dynamical resources: consumption of non-Markovianity for noise reduction

A great many efforts are dedicated to developing noise reduction and mitigation methods. One remarkable achievement in this direction is dynamical decoupling (DD), although its applicability remains limited because fast control is required. Using resource theoretic tools, we show that non-Markovianity is a resource for noise reduction, raising the possibility that it can be leveraged for noise reduction where traditional DD methods fail. We propose a non-Markovian optimisation technique for finding DD pulses. Using a prototypical noise model, we numerically demonstrate that our optimisation-based methods are capable of drastically improving the exploitation of temporal correlations, extending the timescales at which noise suppression is viable by at least two orders of magnitude, compared to traditional DD which does not use any knowledge of the non-Markovian environment. Importantly, the corresponding tools are built on operational grounds and can be easily implemented to reduce noise in the current generation of quantum devices.

Ocean 2D eddy energy fluxes from small mesoscale processes with SWOT

Abstract. We investigate ocean dynamics at different scales in the Agulhas Current system, a region of important interocean exchange of heat and energy. While ocean observations and some of the most advanced climate models capture the larger mesoscale dynamics (> 100 km), the smaller-scale fronts and eddies are underrepresented. The recently launched NASA–CNES Surface Water and Ocean Topography (SWOT) wide-swath altimeter mission observes the smaller ocean geostrophic scales down to 15 km in wavelength globally. Here we will analyse different eddy diagnostics in the Agulhas Current region and quantify the contributions from the larger mesoscales observable today and the smaller scales to be observed with SWOT. Surface geostrophic diagnostics of eddy kinetic energy, strain, and energy cascades are estimated from modelled sea surface height (SSH) fields of the Massachusetts Institute of Technology general circulation model (MITgcm) latitude–longitude polar cap (LLC4320) simulation subsampled at 1/10∘. In this region, the smaller scales (<150 km) have a strong signature on the horizontal geostrophic strain rate and for all eddy diagnostics in the Western Boundary Current and along the meandering Agulhas Extension. We investigate the horizontal cascade of energy using a coarse-graining technique, and we observe that the wavelength range where the inverse cascade occurs is biased towards larger mesoscale wavelengths with today’s altimetric sampling. We also calculate the projected sampling of the eddy diagnostics under the SWOT swaths built with the NASA–CNES simulator to include the satellite position and realistic noise. For the swaths, a neural network noise mitigation method is implemented to reduce the residual SWOT random error before calculating eddy diagnostics. In terms of SSH, observable wavelengths of 15 to 20 km are retrieved after neural network noise mitigation, as opposed to wavelengths larger than 40 km before the noise reduction.

Advanced Power Cycling Test Integrated With Voltage, Current, Temperature, and Humidity Stress

In this article, an advanced power cycling test with high voltage, large current, high temperature, and high humidity stress is proposed to get closer to the actual working conditions of power electronics in the accelerated aging test. The proposed test, integrated with High-Voltage High Humidity High Temperature Reverse Bias Test (HV-H3TRB) and standard DC Power Cycling Test (PCT), achieves precise measurement at the microsecond, millivolt, and microampere accuracy. A 6-kV/750-A prototype is built to verify the feasibility and effectiveness, and the noise mitigation method for measurement under high voltage is analyzed. The proposed test was carried out on the full-bridge power modules for electric vehicles, and the lifetime exhibits lower than the standard PCT. The root cause is the increment of thermal resistance at an early stage due to moisture invasion, which results in a failure mode change. Finally, the electrochemical corrosion signs induced by sulfur/carbon under voltage, temperature, and humidity stress are also revealed by optical inspection and Scanning Electron Microscope (SEM).

Adjusted Controlled Pass-By (CPB) Method for Urban Road Traffic Noise Assessment

Noise associated with road infrastructure is a prominent problem in environmental acoustics, and its implications with respect to human health are well documented. Objective and repeatable methodologies are necessary for testing the efficacy of sustainable noise mitigation methods such as low noise emission pavement. The Controlled Pass-By (CPB) method is used to measure the sound generated by passing vehicles. Despite its popularity, the applicability of CPB is compromised in urban contexts, as its results depend on test site conditions, and slight changes in the experimental setup can compromise repeatability. Moreover, physical conditions, reduced space, and urban elements risk confine its use to only experimental road sites. In addition, vehicle speed represents a relevant factor that further contributes to the method’s inherent instability. The present paper aims to extend the applicable range of this method and to provide more reliable results by proposing an adjusted CPB method. Furthermore, CPB metrics such as LAmax do not consider the travelling speed of the vehicle under investigation. Our proposed method can yield an alternative metric that takes into account the duration of the noise event. A hypothetical urban case is investigated, and a signal processing pipeline is developed to properly characterize the resulting data. Speed cushions, manhole covers, and other spurious effects not related to the pass-by sound emissions of ordinary vehicles are pinpointed as well.

Sheet Pile Tuned Mass Damper for Construction Noise Control

Sheet piles are often used for underground retaining structures. For dense geology, vibratory driven method is more cost-effective than press-in driven method, but noisier. Conventional mitigations such as noise barrier or enclosure are not applicable due to the large size of pile wall (generally >12m high and >10m width). Acoustic camera images revealed that noise radiation was dominant at 630Hz to 2000Hz and mainly came from the sheet-pile wall rather than the vibratory exciter. Vibration response measurement showed the sheet piles had two major resonance modes at 1000 and 2000Hz. An innovative noise mitigation method was developed with 14 nos. of tuned mass dampers (TMD) distributed along a 5m long aluminum tube for vibration energy dissipation at the pile wall. Specific magnetic mounts were developed for quick and easy attachment of the TMDs at the construction site. In the site test, total 6 aluminum tubes (i.e., 84 TMDs) were mounted to the 1st, 2nd and 3rd piles adjacent to the driven pile on both sides. Vibration reduction was measured ~9 to 14dB at the pile wall. Noise reduction was measured 7 to 9dB(A) at 2 noise monitoring locations (~7m and ~22m from the pile wall).

Noise and Vibration in Switched Reluctance Motors: A Review on Structural Materials, Vibration Dampers, Acoustic Impedance, and Noise Masking Methods

Today, the majority of the commercial electrified vehicles use Interior Permanent Magnet Motors (IPMSMs) for propulsion. An IPMSM can deliver high starting torque and high efficiency in the low- and medium-speed operation, which makes it attractive for propulsion applications. However, IPMSMs generally utilize rare-earth permanent magnets and there are growing concerns about the price volatility and supply chain of these materials. Switched Reluctance Motors (SRMs) can potentially replace IPMSMs in various applications including propulsion. An SRM has a simple and low-cost construction, and it can provide reliable operation at high-speed and high-temperature conditions. Compared to IPMSMs, SRMs radiate considerably higher acoustic noise, which have historically hindered their widespread acceptance. Various approaches to mitigate acoustic noise and vibration at the source level have already been explored in the literarture by improving the electromagnetic design and current control. This paper explores multiple noise and vibration mitigation methods that can be applied at the transmission stage. First, the noise comparison between the Internal Combustion Engine (ICE) and SRMs is discussed, and then the methods used for ICEs are presented for their applicability to SRMs.

A SPICE-Compatible Model to Simulate RFI-Induced Buzz Noise Problem in a Camera

This article proposeda SPICE-compatible model to fast simulate the buzz noise problem in a camera device. Based on the reciprocity theorem, the proposed SPICE-compatible model consists of cascaded scattering (S) parameters extracted from the field coupling. It can provide an accurate estimation of the buzz noise transfer function (TF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">total</sub> ) between the radio-frequency antenna and the audio system within an average error of 1 dB. Besides, the proposed model allows for coupling decomposition by separating the audio system into different regions, fast buzz noise mitigation by adding filtering circuits, and fast antenna evaluation/selection by characterizing the TF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">total</sub> with different antenna structures. The advantage of the proposed model is that, instead of multiple 3-D simulations during the predesign-stage troubleshooting, it is a fast SPICE-compatible method with SPICE simulation time of 4.5 min and one-time 3-D full-wave simulation on the camera system studied. It provides quick estimation on the potential buzz noise problems, coupling decomposition,buzz noise mitigation methods, and selection of antenna structures.

A REVIEW OF THE PSYCHOLOGICAL EFFECT OF ENVIRONMENTAL SOUND

Few studies have stressed how access to high-quality acoustic environment affects wellbeing, quality of life, and environmental health. The acoustic environment influenced by noise pollution reduces the restorative effect generated by the natural environment. Noise policies which focus on noise level as a determinant of wanted and unwanted sounds are inadequate to control the acoustic quality of the environment. Therefore, this paper aims to identify the psychological effect of environmental sound and the direction of study for environmental sound research from 1993 to 2020. Review works of literature were identified through multiple interdisciplinary health, environmental, and urban planning databases in available open access journals. The focus of the study will look into keywords of "environmental sound", "noise", “acoustic environment” and "mental health". The review showed that previous study focused on the negative effect of noise and noise mitigation methods through the noise level controls in the guidelines. On the other hand, recent reviews continue to discuss the impact of noise further and add on a positive view of the psychological effect of environmental sound. Noise mitigation methods also focused on enhancing positive sounds and methods for a more comprehensive study of the environmental sound.

Review of the CM noise mitigation methods for the single-phase power factor correction converter

Several techniques to mitigate conducted electromagnetic interference (EMI) in single-phase power factor correction (PFC) converters have been reported in literatures. This paper mainly focuses on the review and classifications of the common-mode (CM) noise mitigation methods based on the novel structures, balance concept, novel modulation methods and so on. Through eliminating the noise generation or cut off the propagation path, those methods can mitigate the CM noise caused by the single-phase PFC converter. Besides, the comparisons and limitations are also discussed. It is believed that this review will be helpful to the design of the EMI filter for the switch-mode power system, which includes the PFC stages.

Effects of Dynamical Decoupling and Pulse-Level Optimizations on IBM Quantum Computers

Currently available quantum computers are prone to errors. Circuit optimization and error mitigation methods are needed to design quantum circuits to achieve better fidelity when executed on NISQ hardware. Dynamical decoupling (DD) is generally used to suppress the decoherence error and different DD strategies have been proposed. Moreover, the circuit fidelity can be improved by pulse-level optimization, such as creating hardware-native pulse-efficient gates. This paper implements all the popular DD sequences and evaluates their performances on IBM quantum chips with different characteristics for various well-known quantum applications. Also, we investigate combining DD with pulse-level optimization method and apply them to QAOA to solve Max-Cut problem. Based on the experimental results, we found that DD can be a benefit for only certain types of quantum algorithms, while the combination of DD and pulse-level optimization methods always has a positive impact. Finally, we provide several guidelines for users to learn how to use these noise mitigation methods to build circuits for quantum applications with high fidelity on IBM quantum computers.

Review of the CM noise mitigation methods for the single-phase power factor correction converter

Review of the CM noise mitigation methods for the single-phase power factor correction converter

Indexed improvements for real-time trotter evolution of a (1 + 1) field theory using NISQ quantum computers

Today’s quantum computers offer the possibility of performing real-time calculations for quantum field theory scattering processes motivated by high energy physics. In order to follow the successful roadmap which has been established for the calculation of static properties at Euclidean time, it is crucial to develop new algorithmic methods to deal with the limitations of current noisy intermediate-scale quantum (NISQ) devices and to establish quantitative measures of the progress made with different devices. In this paper, we report recent progress in these directions. We show that nonlinear aspects of the trotter errors allow us to take much larger step then suggested by low-order analysis. This is crucial to reach physically relevant time scales with today’s NISQ technology. We propose to use an index averaging absolute values of the difference between the accurately calculated trotter evolution of site occupations and their actual measurements on NISQ machines (G index) as a measure to compare results that have been obtained from different hardware platforms. Using the transverse Ising model in one spatial dimension with four sites we apply this metric across several hardware platforms. We study the results including readout mitigation and Richardson extrapolations and show that the mitigated measurements are very effective based on the analysis of the trotter step size modifications. We discuss how this advance in the trotter step size procedures can improve quantum computing physics scattering results and how this technical advance can be applied to other machines and noise mitigation methods.

A Novel 1/f Noise Mitigation Technique Applied to a 670 GHz Receiver

In this letter, a novel 1/f noise mitigation technique is presented to improve the receiver 1/f noise performance of a 670 GHz receiver. The time-domain 1/f noise corrected samples are compared with the samples obtained without the correction. The spectral-domain analysis shows that the 1/f noise mitigation method improves the receiver noise performance by 19 dB in the receiver under test. The presented 1/f noise mitigation technique can be applied to any direct-detection receiver in the terahertz frequency range.

High-resolution reconstructions and GPS estimates of India–Eurasia and India–Somalia plate motions: 20 Ma to the present

SUMMARY We reconstruct the movement of the India Plate relative to Eurasia at ≈1-Myr intervals from 20 Ma to the present from GPS site velocities and high-resolution sequences of rotations from the India–Somalia–Antarctic–Nubia–North America–Eurasia Plate circuit. The plate circuit rotations, which are all estimated using the same data fitting functions, magnetic reversal sampling points, calibrations for magnetic reversal outward displacement, and noise mitigation methods, include new India–Somalia rotations estimated from numerous Carlsberg and northern Central Indian ridge plate kinematic data and high-resolution rotations from the Southwest Indian Ridge that account for slow motion between the Nubia and Somalia plates. Our new rotations indicate that India–Somalia plate motion slowed down by 25–30 per cent from 19.7 to 12.5–11.1 Ma, but remained steady since at least 9.8 Ma and possibly 12.5 Ma. Our new India–Eurasia rotations predict a relatively simple plate motion history, consisting of NNE-directed interplate convergence since 19 Ma, a ≈50 per cent convergence rate decrease from 19.7 to 12.5–11.1 Ma, and steady or nearly steady plate motion since 12.5–11.1 Ma. Instantaneous convergence rates estimated with our new India–Eurasia GPS angular velocity are 16 per cent slower than our reconstructed plate kinematic convergence rates for times since 2.6 Ma, implying either a rapid, recent slowdown in the convergence rate or larger than expected errors in our geodetic and/or plate kinematic estimates. During an acceleration of seafloor faulting within the wide India–Capricorn oceanic boundary at 8–7.5 Ma, our new rotations indicate that the motions of the India Plate relative to Somalia and Eurasia remained steady. We infer that forces acting on the Capricorn rather than the India Plate were responsible for the accelerated seafloor deformation, in accord with a previous study. India–Eurasia displacements that are predicted with our new, well-constrained rotations are fit poorly by a recently proposed model that attributes the post-60-Ma slowdown in India–Eurasia convergence rates to the steady resistance of a strong lithospheric mantle below Tibet.

Striping Noise Analysis and Mitigation for Microwave Temperature Sounder-2 Observations

The Microwave Temperature Sounder (MWTS)-2 has a total of 13 temperature-sounding channels with the capability of observing radiance emissions from near the surface to the stratosphere. Similar to the Advanced Technology Microwave Sounder (ATMS), striping pattern noise, primarily in the cross-track direction, exists in MWTS-2 radiance observations. In this study, an algorithm based on principal component analysis (PCA) combined with ensemble empirical mode decomposition (EEMD) is described and applied to MWTS-2 brightness temperature observations. It is arguably necessary to smooth the first three principal component (PC) coefficients by removing the first four intrinsic mode functions (IMFs) using the EEMD method (denoted as PC3/IMF4). After the PC3/IMF4 noise mitigation, the striping pattern noise is effectively removed from the brightness temperature observations. The noise level in MWTS-2 observations is significantly higher than that detected in ATMS observations. In May 2014, the scanning profile of MWTS-2 was adjusted from varying-speed scanning to constantspeed scanning. The impact on striping noise levels brought on by this scan profile change is also analyzed here. The striping noise in brightness temperature observations worsened after the profile change. Regardless of the scan profile change, the striping noise mitigation method reported in this study can more or less suppress the noise levels in MWTS-2 observations.

A Robust Noise Mitigation Method for the Mobile RFID Location in Built Environment.

The exact location of objects, such as infrastructure, is crucial to the systematic understanding of the built environment. The emergence and development of the Internet of Things (IoT) have attracted growing attention to the low-cost location scheme, which can respond to a dramatic increasing amount of public infrastructure in smart cities. Various Radio Frequency IDentification (RFID)-based locating systems and noise mitigation methods have been developed. However, most of them are impractical for built environments in large areas due to their high cost, computational complexity, and low noise detection capability. In this paper, we proposed a novel noise mitigation solution integrating the low-cost localization scheme with one mobile RFID reader. We designed a filter algorithm to remove the influence of abnormal data. Inspired the sampling concept, a more carefully parameters calibration was carried out for noise data sampling to improve the accuracy and reduce the computational complexity. To achieve robust noise detection results, we employed the powerful noise detection capability of the random sample consensus (RANSAC) algorithm. Our experiments demonstrate the effectiveness and advantages of the proposed method for the localization and noise mitigation in a large area. The proposed scheme has potential applications for location-based services in smart cities.