Equivalent Noise Level Research Articles

Spherical near-field measurement of the offset vehicle antenna mounted on a vehicle

For the vehicle antenna measurement mounting on a vehicle, the offset mounting of the antenna will increase the maximum spherical wave expansion modes, with the increasing calculation time and the increasing risk of introducing environmental reflection noise. Therefore, basing on the matrix form of the traditional spherical wave expansion (TSWE) algorithm, this paper introduces the offset spherical wave expansion (OSWE) algorithm of the offset mounting antenna under test (AUT) aiming to decrease the maximum modes, shorten the calculation time and reduce the environmental noise with the method of spherical wave expansion. Taking LTE antenna and GPS antenna as examples, this paper analyzes the improved performance of OSWE algorithm comparing with TSWE algorithm on the vehicle antenna mounting on a vehicle, as well as the parameters like equivalent noise level (ENL), omnidirectional standard deviation (σ).

Evaluating the aircraft noise level and acoustic performance of the buildings in the vicinity of Dubai International Airport

Airports, especially international ones, within the urban context should have a specific consideration so they do not affect human lives. The planes fly a few hundred meters above these urban fabrics, and when they are landing, they fly slightly over 20–40 m above the ground. This paper aims to measure aircraft noise, conduct a survey on the subjective reaction of residents to aircraft noise, and present primary data necessary to secure the acoustic performance of residential buildings neighboring an international airport. The methodology used a field survey for six buildings neighboring Dubai International Airport in the United Arab Emirates, analyzed building/window material, and a subjective reaction survey. The result showed that the average equivalent noise level (Leq) was 66.4 dB(A), and the average maximum noise level (Lmax) was 73.3 dB(A). The indoor noise of the target buildings was found to be in the range of NC-35 to NC-53, exceeding NC-30, the permissible noise standard. The average noise level difference between indoors and outdoors was 13.6–30.5 dB(A). It was statistically proven that aircraft noise is a significant source of sound pollution and occurs all day throughout the year, regardless of the season. The response rate for loudness and noisiness was found to be very high. Regarding the disturbance in daily life due to annoyance, aircraft noise is significantly affected in the order of telephone calls, conversations, listening to TV and radio, sleep disturbance, concentration disturbance, and rest disturbance. This study will serve as primary data to present basic data necessary to secure an optimum acoustic performance of a residential building against aircraft noise.

CT image quality evaluation in the age of deep learning: trade-off between functionality and fidelity.

To quantitatively compare DLIR and ASiR-V with realistic anatomical images. CT scans of an anthropomorphic phantom were acquired using three routine protocols (brain, chest, and abdomen) at four dose levels, with images reconstructed at five levels of ASiR-V and three levels of DLIR. Noise power spectrum (NPS) was estimated using a difference image by subtracting two matching images from repeated scans. Using the max-dose FBP reconstruction as the ground truth, the structure similarity index (SSIM) and gradient magnitude (GM) of difference images were evaluated. Image noise magnitude (σ), frequency location of the NPS peak (fpeak), mean SSIM (MSSIM), and mean GM (MGM) were used as quantitative metrics to compare image quality, for each anatomical region, protocol, algorithm, dose level, and slice thickness. Image noise had a strong (R2 > 0.99) power law relationship with dose for all algorithms. For the abdomen and chest, fpeak shifted from 0.3 (FBP) down to 0.15 mm-1 (ASiR-V 100%) with increasing ASiR-V strength but remained 0.3 mm-1 for all DLIR levels. fpeak shifted down for the brain protocol with increasing DLIR levels. Three levels of DLIR produced similar image noise levels as ASiR-V 40%, 80%, and 100%, respectively. DLIR had lower MSSIM but higher MGM than ASiR-V while matching imaging noise. Compared to ASiR-V, DLIR presents trade-offs between functionality and fidelity: it has a noise texture closer to FBP and more edge enhancement, but reduced structure similarity. These trade-offs and unique protocol-dependent behaviors of DLIR should be considered during clinical implementation and deployment. • DLIR reconstructed images demonstrate closer noise texture and lower structure similarity to FBP while producing equivalent noise levels comparable to ASiR-V. • DLIR has additional edge enhancement as compared to ASiR-V. • DLIR has unique protocol-dependent behaviors that should be considered for clinical implementation.

Acoustic Indicators for Motor Race Noise: Definition, Validation, and Tests in Simulated and Real Races

Although the road transport sector, together with railways, airports, and industries represent the major contributors to noise pollution in Europe, also other minor activities, scarcely explored in the literature, can have a non-negligible role on a local scale. This is the case of motorsport races. During these types of events, vehicles produce notable noise emissions while are on track during tests, qualifying, and race sessions. As a consequence, they may, directly or indirectly, affect the well-being of inhabitants in the surrounding area of the circuit, and expose the public, workers, and all the other possible Noise Sensitive Receivers (NSRs) to high noise levels. Therefore, a thorough analysis of the noise levels produced during motorsport events at sensible receivers is strongly needed, to better assess NSRs’ exposure and gather information on the possible measures to reduce noise to acceptable levels.This works aims to address this topic, by proposing the definition of two noise indicators: the Lap Equivalent Level (LEL) and the Race Equivalent Level (REL). LEL defines the equivalent noise level at a certain receiver due to a single-vehicle track lap, and REL the equivalent noise level produced during a race.Noise data were collected on different points along a racing circuit during a single-vehicle track test and different car races, to apply in practice the defined indicators. Measurements show that the REL tends to stabilize its values during a race, suggesting that its modeling can be achieved based on the average LEL and the number of vehicles participating in a race. Instead, the duration of the race does not play a key role in the estimation of REL values but, rather, gives information on the NSRs’ exposure time to race noise levels. Estimations of RELs were carried out for real and simulated races. A comparison with available measured values shows good performance of the indicators suggesting that the proposed approach could be appropriate.

Effect of wearing helmet on traffic noise-induced health issues of motorcycle riders

IntroductionTransportation noise is a major source of concern in urban areas. Motorcycle riders, on the other hand, are the most exposed to traffic noise while riding. This study was carried out on 363 respondents (no-helmet: 121 respondents, half-face helmet: 121 respondents, and full-face helmet: 121 respondents) who were exposed to traffic noise while riding their motorcycles on the same noisy route, having the same exposure hours. The purpose of this study was to determine whether wearing a helmet protects against various traffic noise-induced psychophysiological health issues. It also tried to determine whether the riders were more affected than the pillion riders as a result of traffic noise exposure. MethodThe psychophysiological factors of the respondents, such as annoyance, tiredness, depression, headache, and sleeping problem, were obtained using a standard questionnaire in accordance with ISO 15666, Beck et al. (1961), and Eriksen et al. (1999), respectively. The effect of wearing a helmet on traffic noise-induced psychophysiological reactions was investigated using structural equation modelling. ResultsSEM route analysis revealed these significant relationships: (i) helmet use and gender (p-value: 0.017), (ii)) helmet use and marital status (p-value: 0.043), (iii) riders/pillion-riders and annoyance (p-value: < 0.001), (iv) riders/pillion-riders and gender (p-value: < 0.001). It was also observed that motorcyclists suffer from higher traffic noise-related health issues than pillion riders. SEM analysis further revealed that use of helmet can negatively affect the traffic noise induced annoyance, tiredness, depression, headache, and sleeping problem. Paired test data shows that there are significant differences in traffic noise induced annoyance level, tiredness, headache, depression, sleeping problems, and equivalent noise level. ConclusionThe use of a full-face helmet protects motorcyclists against a variety of traffic noise-related health problems. Practical implicationsThis study presents a thorough overview of the benefits of wearing a helmet against traffic noise pollution.

METHODS OF EXPERIMENTAL RESEARCH OF NOISE POLLUTION FROM ROAD TRANSPORT AND ACOUSTIC PARAMETERS OF NOISE PROTECTION SCREENS

A review of scientific work on the main sources of noise from road transport and its impact on human health. Measures to reduce the level of noise load on the environment are analyzed. It is established that in projects of construction and reconstruction of highways measures of reduction of noise loading of motor transport on adjoining territories to highways, especially within settlements, should be considered. The method is given and experimental measurements of noise load from highways to the adjacent territories depending on the distance from the noise source to the residential area are carried out. It was found that the equivalent sound level in the area adjacent to the residential area, at a distance of 2 m is 74.4 dBA, and the maximum sound level ‒ 78.0 dBA. When measuring the noise characteristics at a distance of 1 m in front of the noise shield, the equivalent sound level was 88.6 dBA, and the maximum sound level was 103.9 dBA. At a distance of 2.4 m from the noise shield, the equivalent sound level was 70.7 dBA, and the maximum sound level was 89.8 dBA. It was found that during the experimental measurements at a distance of 19.5 m from the existing highway and at a distance of 2 m from residential buildings, the measured equivalent noise level exceeded the established normative value by 19.4 dBA, and the measured maximum noise level exceeded the established normative value by 8.0 dBA. Experimental measurements of acoustic efficiency parameters of noise protection screens were performed. It is established that noise protection screens are effective means of reducing the noise transport load on the environment. At a distance of 2 m from the noise protection screen, the acoustic efficiency of the screen is 11-16 dBA.

Identification of monitoring stations for noise levels in Durrës city, Albania

Abstract This paper represents a noise pollution survey in Durrës city, Albania. There are four survey areas defined: A (central), B (industrial), C (suburban), D (residential + beach) during two intervals times (morning and night). The equipment used for noise measurement was Testo 816-1 where data were categorized according to levels L eq , L min, L max, and L ave . The contrast of L eq levels versus the standard levels based on the 2002/49/EC Directive showed that L eq levels overcome the limits. In conclusion, the high equivalent noise level mostly has been during the morning with L eq &gt; 55 dB, which brings serious health concerns to residents near these regions. At night in most of these stations, the equivalent noise levels resulted higher than 45 dB, which is above EU directive and Albanian standards. The survey results will also serve local institutions to manage the situation and to address problems at the governmental level.

Time-series prediction and forecasting of ambient noise levels using deep learning and machine learning techniques

Ambient day and night noise levels prediction problems have traditionally been addressed using various statistical and machine learning methods. This paper presents the time-series predictions and forecasting of ambient noise levels using support vector machine (SVM) and deep learning method such as convolutional neural network (CNN) approach. This approach has been rarely reported for modeling ambient noise levels so far, although it has been widely used in air and water pollution predictions and forecasting. The study presents the applications of these techniques in time-series modeling of ambient day and night equivalent noise levels. A case study of ambient noise levels of one site each lying in commercial, residential, industrial and silence zone is presented. Ten-fold cross-validation is used in SVM model to train the model effectively and determine the optimized value of hyper-parameter (g, «, C). Also, CNN with a convolutional and pooling layer architecture framework is designed with optimum value of batch size, activation function, and filter size, among others. The validation and suitability of developed SVM and CNN models are ascertained by various statistical tests. Convolutional neural network approach is observed to outperform SVM model and thus can be a reliable approach for time-series modeling of ambient noise levels with a prediction error of 2.1 dB(A). The forecasting root mean squared error obtained for all the four zones using CNN model is observed to be less than 2.1 dB(A) for day equivalent noise levels and 1.9 dB(A) for night equivalent noise levels.

Effect of lockdown amid second wave of COVID-19 on environmental noise scenario of the megacity Delhi, India.

This paper analyzes the impact of second wave of COVID-19 lockdown on environmental noise levels of 25 sites in Delhi city and compares the noise scenario during pre-lockdown, lockdown, and post-lockdown periods. The study utilized the noise monitoring data acquired from 25 real-time ambient noise monitoring stations, installed by the Delhi Pollution Control Committee, Delhi, at various sites throughout Delhi city. A significant reduction of up to 10 and 3 dB(A) in day and night equivalent noise levels, respectively, had been observed during the lockdown period as compared to the pre-lockdown and post-lockdown periods. The study also revealed that only nine sites, including four industrial and five commercial zone sites, complied with the ambient noise standards during lockdown period, and no silence or residential zone sites complied with the ambient noise standards even during the lockdown period. A roadmap for environmental noise management and control is suggested. The study also reports the community's perception toward the change in acoustic environment of Delhi city during the lockdown period by conducting an environmental noise perception survey. The present study should be helpful in devising noise control action plans and policy interventions for environmental noise management and control in the metropolitan city Delhi, India.

Analysis Noise Level in Production the Palm Oil: A Case Study

Excessive noise exposure during the manufacturing process is a widespread issue. This research aimed to analyze noise exposure in the kernel recovery station in the manufacturing process of palm oil. We conduct some measurements and calculations for noise exposure analysis to get the Equivalent Noise Level (Leq) value during the daytime for each measurement point. The noise measurement was conducted on four machines, including a depericarper and polishing drum machine, ripple mill machine, silo dryer machine, and clay bath machine. In addition, this research showed noise contour mapping to define the noise distribution. The results of this research are that only the clay bath machine had Ls below the threshold. The clay bath machine workstation has good noise levels. The Depericarper, Polishing Drum, Ripple Mill, and Silo Dryer Machine must be quieter. Thus, this research used the Hierarchy of Control Approach to reduce and control hazardous noise exposure. The stage of HOC includes elimination, substitution, engineering, administrative control, and Personal Protective Equipment (PPE).

Music Therapy Intervention in an Open Bay Neonatal Intensive Care Unit Room Is Associated with Less Noise and Higher Signal to Noise Ratios: A Case-Control Study.

Background: Noise reduction in the Neonatal Intensive Care Unit (NICU) is important for neurodevelopment, but the impact of music therapy on noise is not yet known. Objective: To investigate the effect of music therapy (MT) on noise levels, and whether individual MT (IMT) or environmental MT (EMT) increases meaningful signal-to-noise ratios (SNR). Study design: This case-control study was conducted in a level III NICU. Noise levels were recorded simultaneously from two open bay rooms, with a maximum of 10 infants in each room: one with MT and the other without. MT sessions were carried out for approximately 45 min with either IMT or EMT, implemented according to the Rhythm Breath and Lullaby principles. Noise production data were recorded for 4 h on 26 occasions of EMT and IMT, and analyzed using R version 4.0.2 software. Results: Overall average equivalent continuous noise levels (Leq) were lower in the room with MT as compared to the room without MT (53.1 (3.6) vs. 61.4 (4.7) dBA, p = 0.02, d = 2.1 (CI, 0.82, 3.42). IMT was associated with lower overall Leq levels as compared to EMT (51.2 vs. 56.5 dBA, p = 0.04, d = 1.6 (CI, 0.53, 1.97). The lowest sound levels with MT occurred approximately 60 min after the MT started (46 ± 3.9 dBA), with a gradual increase during the remaining recording time, but still significantly lower compared to the room without MT. The SNR was higher (18.1 vs. 10.3 dBA, p = 0.01, d = 2.8 (CI, 1.3, 3.86)) in the room with MT than in the room without MT. Conclusion: Integrating MT modalities such as IMT and EMT in an open bay NICU room helps reduce noise. Both MT modalities resulted in higher SNR compared to the control room, which may indicate that they are meaningful for the neurodevelopment of preterm infants.

Soundscape Assessment for Indoor Spaces: A case of the Higher Education Environment

As a concept, an indoor soundscape is an innovative approach to building environments with a shape that "sounds good," meeting the preferences and needs of the occupants and established according to their unique indoor soundscape perception. This paper presents the assessment of the indoor soundscape regarding objective acoustic parameters such as the equivalent noise levels (Leq) and the reverberation time (RT), and subjective method including a questionnaire survey (n = 403) in three buildings of Engineering in Al-Azhar university. The data analyses were conducted using SPSS v.21 statistical software. Overall, results show that indoor assessment is associated with five factors that are: acoustic environment factors, demographics and social factors, sound sources, duration and time of measurement, and non-acoustic parameters. The conceptual framework showed the relations between the acoustic environment, built environment, and auditory perception of university students and staff. Various buildings present a series of acoustic problems based on different activities that change the perception of users, so the outcomes feature the importance in the future considering the type of activity as a key factor in assessing the effects of noise on humans.

Prediction of traffic noise induced annoyance of vendors through noise indices using structural equation modeling: Artificial neural network model

AbstractUrbanization and population growth, as well as the movement of diverse vehicles on urban roadways, all contribute to excessive noise in the urban acoustic environment. Annoyance, cardiovascular disease, dementia, hypertension, stress, sleeping problem, irritation, hair‐fall, headache, are the most common reported problems due to traffic noise exposure. The “Structural Equation Modeling–Artificial Neural Network Model” was used in the current study to predict traffic noise induced annoyance among 100 vendors whose shops are located from Khandagiri to Baramunda along the National Highway 16 of the smart city Bhubaneswar Odisha. Due to the movement of large number of heavy vehicles as well as medium and light weight vehicles, these roadways remain noisy throughout the day. Moreover, the annoyance questionnaire was developed in compliance with ISO/TS 15666 criteria for assessing annoyance level. The combination of SEM and ANN is rarely seen in acoustics, especially in noise studies. However, in this study, both SEM and ANN are used to predict annoyance using various noise indices. Moreover, the SEM model revealed a significant association between “Equivalent Noise Level” (Leq) and annoyance (p‐value = 0.031), “Minimum Noise Level” (LMin) and annoyance (p‐value = 0.049), “Background Noise Level” (L90) and annoyance (p‐value = 0.047), “Noise Pollution Level” (NPL) and annoyance (p‐value = 0.038). These associations indicate that Leq, LMin, L90 and NPL have a significant effect on annoyance. Furthermore, the PLS algorithm output from the measurement model verified a 47 percent variance in annoyance level. The ANN model confirmed that NPL is the most significant predictor of noise annoyance, followed by LMin, Leq, and L90. Moreover, the ANN model can predict annoyance with an accuracy of 68.5 percent.

Assessment of Indoor Climate for Infants in Nursery School Classrooms in Mild Climatic Areas in Japan

In Japan, the standard of indoor climate in nursery school classrooms has not been established, and the control and maintenance of indoor climate in the classrooms are entrusted to individual childminders. Therefore, indoor climate in nursery school classrooms was measured to prepare fundamental information for proper environmental design and environmental control, considering infants’ comfort and health. The climate of 0-year-old and 1-year-old children’s rooms in 15 nursery schools located in mild climatic areas in Japan were measured in the summer and winter over four years. Consequently, a lower average temperature was found during winter at lower heights at which infants spend time and indoor air quality was found to be poor in both summer and winter due to a lower ventilation rate in some classrooms with a smaller area per infant compared to the minimum standards for child welfare institutions. One classroom with an average CO2 concentration of over 1500 ppm was found in both summer and winter due to less ventilation. Illumination less than 300 lx in one-third of the studied classrooms and high equivalent noise level in most classrooms were measured. The need for indoor environmental standards was indicated in terms of infants’ comfort and health.

Creation of an incus recess for a middle-ear microphone using a drill or laser ablation: a comparison of equivalent noise level and middle ear transfer function

PurposeStudies have assessed the trauma and change in hearing function from the use of otological drills on the ossicular chain, but not the effects of partial laser ablation of the incus. A study of the effectiveness of a novel middle-ear microphone for a cochlear implant, which required an incus recess for the microphone balltip, provided an opportunity to compare methods and inform a feasibility study of the microphone with patients.MethodsWe used laser Doppler vibrometry with an insert earphone and probe microphone in 23 ears from 14 fresh-frozen cadavers to measure the equivalent noise level at the tympanic membrane that would have led to the same stapes velocity as the creation of the incus recess.ResultsDrilling on the incus with a diamond burr created peak noise levels equivalent to 125.1–155.0 dB SPL at the tympanic membrane, whilst using the laser generated equivalent noise levels barely above the baseline level. The change in middle ear transfer function following drilling showed greater variability at high frequencies, but the change was not statistically significant in the three frequency bands tested.ConclusionsWhilst drilling resulted in substantially higher equivalent noise, we considered that the recess created by laser ablation was more likely to lead to movement of the microphone balltip, and therefore decrease performance or result in malfunction over time. For patients with greatly reduced residual hearing, the greater consistency from drilling the incus recess may outweigh the potential benefits of hearing preservation with laser ablation.

Assessment of Noise Exposure Indices at Kanchijhuli and Townhall Moor in Mymensingh City

Mymensingh, one of Bangladesh's most densely populated and urbanized cities, could not avoid a noise-related problem that has now turned out into a severe environmental issue. It is indispensable to assess the current noise propagation scenario and its repercussions for urban planners to manage the noise problem. This research endeavours to construct noise pollution indices viz. noise levels (L10, L50, L90), noise climate (NC), equivalent continuous noise level (Leq), noise pollution level (Lnp), and noise exposure index (NEI) were computed for two important particular locations, namely Kanchijhuli and Townhall moor. It was also observed that most of the time, the noise level exceeded 80 dB, which is beyond the recommended level of silent zone, commercial zone and traffic zone according to the DoE (1997). The indices indicated that the noise level of the study area surpassed the normal noise level in all indices. NC, Leq and Lnp were estimated to have a maximum value of 17.32 dB, 94.29 dB and 110.30 dB, respectively, while the minimum value of the study area were 10.71 dB, 82.07 dB and 95.5 dB, respectively. Therefore, it can be stated from the assessment that both Kanchijhuli and Townhall moor are under alarming noise pollution conditions. This research may aid in taking necessary measures to cut off the noise propagation and subsequent noise pollution control for the urban planners and related authorities.&#x0D; Environ. Sci. &amp; Natural Resources, 13(1&amp;2): 19-24, 2020

Association between traffic noise-induced psychophysiological, and socio-demographic factors of motorcycle riders

This is an exposure effect research carried out in Bhubaneswar with 363 motor cycle riders (equal exposure hours) who go to and from work every day on a specific path. The acoustic environment of 14 major squares along this route was measured, and the equivalent noise level was found to be higher than the permissible limit. The demographics and psychophysiological (annoyance, sleeping problem, tiredness, headache, and depression) responses of the participants were collected using standard questionnaires. Blood pressure responses were acquired by monitoring blood pressure before and after being exposed to traffic noise in the morning and evening for further analysis. Moreover, Structural Equation Model (SEM) revealed a significant relationship between “gender and blood pressure,” “gender and headache,” “gender and tiredness,” “marital status and blood pressure,” “profession and annoyance,” “sleeping problem and depression,” “annoyance and blood pressure,” “annoyance and depression,” “annoyance and headache,” “annoyance and sleeping problem,” “annoyance and tiredness,” “blood pressure and depression,” “blood pressure and sleeping problem.” However, Artificial Neural Network (ANN) model found blood pressure as the most significant outcome of annoyance, followed by depression, sleeping problems, tiredness, and headache. Furthermore, depression and sleep problems are found to be the second most important outcomes, with a normalized importance of 91%.

Traffic Noise Pollution Assessment in Major Road Junctions of Imphal City, Manipur (India)

Noise pollution assessment was carried out in selected traffic junctions of Imphal city of Manipur, India, using noise parameters and indices such as L10, L50, L90, Leq for the different periods of the day, i.e., morning, noon, and evening hours. The study of equivalent noise level (Leq), noise parameters, and various noise indices have enabled the evaluation of the overall traffic noise environment of the city. The noise indices such as traffic noise index (TNI), noise climate (NC), traffic noise pollution level (LNP), noise exposure index (NEI) along with day time (LD), night time (LN) average, and day-night (Ldn) noise levels were assessed for the selected traffic junctions. Moreover, spatial noise mapping was carried out using the geostatistical interpolation technique to evaluate the changes of traffic noise scenarios during the different time zones of the day. The Leq values in a few traffic junctions exceeded the required noise standards. The study shows equivalent noise levels ranging between 52.2-69.9 dB(A) during the morning (7-10 am), 52.4 -69.3 dB(A) during noon (12 noon-2 pm), and 54.6-71.1 dB(A) during the evening (4-7 pm) hours, respectively.

Case study of noise pollution from vehicles and legal mechanisms for road noise control

Among the many environmental problems of the modern world one of the important ones is noise pollution. Currently, noise pollution from vehicles requires special attention in densely populated and industrial cities, as there is a trend towards an increase in the areas of acoustic discomfort in built-up areas. The noise that occurs on the roadway of the highway extends not only to the territory near the highway, but also deep into the housing development. Study' objective was to assess noise pollution from vehicles in the most densely populated area of Poltava (Ukraine), as well as to establish the possibility of influencing the situation through legal mechanisms to have an understanding of further research directions and ways to achieve a comfortable urban environment in Ukraine. The noise levels from traffic flows were measured in accordance with GOST 20444-2014, using the Testo 815. To determine the equivalent noise level from the traffic flows movement, an empirical dependence was applied in accordance with the methodology of the State Agency for Highways of Ukraine. Determined that the daytime threshold values are exceeded by 20–28.9 dB(A), which is not acceptable. The reasons for the increase in noise are the road bumps, a significant number of cars and number of stops and streets junctions, the movement of vehicles at a non-constant speed, lack of roadside landscaping. About 62,550 people live in areas where the noise level exceeds the permissible value for the area near residential buildings. The calculation method used turned out to be more accurate than the measured results and showed a significant effect of traffic intensity on noise pollution. Apparently, the low measurement accuracy is justified by outdated road noise measurement standards, which, in turn, need to be seriously revised. Reducing noise levels by optimizing traffic flows is one of the priority areas in which it is necessary to bring the environmental legislation of Ukraine. Ukrainian legislation still needs to undergo many changes to reach a level where it can be used as a control lever to achieve a safe ecological environment.

Improving the reproducibility of proton magnetic resonance spectroscopy brain thermometry: Theoretical and empirical approaches.

In proton magnetic resonance spectroscopy (1 H MRS)-based thermometry of brain, averaging temperatures measured from more than one reference peak offers several advantages, including improving the reproducibility (i.e., precision) of the measurement. This paper proposes theoretically and empirically optimal weighting factors to improve the weighted average of temperatures measured from three references. We first proposed concepts of equivalent noise and equivalent signal-to-noise ratio in terms of frequency measurement and a concept of relative frequency that allows the combination of different peaks in a spectrum for improving the precision of frequency measurement. Based on these, we then derived a theoretically optimal weighting factor and proposed an empirical weighting factor, both involving equivalent noise levels, for a weighted average of temperatures measured from three references (i.e., the singlets of NAA, Cr, and Ch in the 1 H MR spectrum). We assessed these two weighting factors by comparing their errors in measurement of temperatures with the errors of temperatures measured from individual references; we also compared these two new weighting factors with two previously proposed weighting factors. These errors were defined as the standard deviations in repeated measurements or in Monte Carlo studies. Both the proposed theoretical and empirical weighting factors outperformed the two previously proposed weighting factors as well as the three individual references in all phantom and in vivo experiments. In phantom experiments with 4-or 10-Hz line broadening, the theoretical weighting factor outperformed the empirical one, but the latter was superior in all other repeated and Monte Carlo tests performed on phantom and in vivo data. The proposed weighting factors are superior to the two previously proposed weighting factors and can improve the reproducibility of temperature measurement using 1 H MRS-based thermometry.