A Low-Noise Amplifier for Submarine Electric Field Signal Based on Chopping Amplification Technology.

In the exploration of ocean resources, the submarine electric field signal plays a crucial role through marine electromagnetic methods. However, due to the field signal's low-frequency and weak characteristics, it often encounters interference from the instrument's own 1/f noise during its acquisition. To address this issue, we developed a low-noise amplifier for the submarine electric field signal based on chopping amplification technology. This amplifier utilizes low-temperature electronic components to adapt to the cold submarine environment and enhances its independence by incorporating a square wave generator. Additionally, we conducted simulations and experimental tests on the designed chopper amplifier circuit, evaluating the equivalent input voltage noise spectrum (EIVNS) and the frequency response within 1 mHz~100 Hz. The experimental results indicate that the amplifier designed in this study achieves sufficiently low noise 2 nV/√Hz@1 mHz, effectively amplifying the submarine electric field signal measured with the electric field sensor.

Nível de ruídos na unidade neonatal / Noise level in the neonatal unit / Nivel de ruido en la unidad neonatal

Objetivo: verificar os níveis de pressão sonora, a influência do turno e das ocorrências nesses níveis em uma unidade neonatal do Rio de Janeiro. Método: estudo longitudinal, exploratório, descritivo, com dados coletados entre novembro de 2021 e janeiro de 2022. As variáveis categóricas foram descritas por meio de frequências absoluta e relativa. A aderência à distribuição normal foi verificada pelo teste Shapiro-Wilk. Para a análise da associação entre variáveis de exposição e desfecho, utilizou-se teste Mann-Whitney, Kruskal Wallis e Qui-quadrado. Considerou-se estatisticamente significativos resultados de p<0,05. Resultados: foram coletados 10.122 registros de decibéis e 56 eventos relacionados as atividades, que ocorreram predominantemente no período diurno. Houve variação de 38,6 a 93,1 decibéis (dB). Em 96,3% do período observado, os níveis de pressão sonora estiveram acima do recomendado. Na comparação entre os períodos, o noturno apresentou menores níveis (p=0,000). Conclusão: os níveis de pressão sonora registrados estão acima do recomendado para um ambiente seguro(AU)

Objective: to verify the sound pressure levels (SPL) and the influence of the shift and the occurrences in these levels in a neonatal unit in Rio de Janeiro. Method: longitudinal, exploratory, descriptive study. Collected from November 2021 to January 2022. Categorical variables were described using absolute and relative frequencies. To verify adherence to the normal distribution, the Shapiro-Wilk test was used. For the association between exposure and outcome variables, the Mann-Whitney, Kruskal Wallis and Qui-square tests were used. Results of p < 0.05 were considered statistically significant. Results: 10,122 decibel records and 56 events related to activities were collected, these occurred predominantly during the day. There was a variation from 38.6 to 93.1 decibels (dB). In 96.3% of the observed period, the NPS were above the recommended. Comparing the periods, nighttime had lower SPL (p=0.000). Conclusion: the registered NPS are above the recommended for a safe environment(AU)

Objetivo: Verificar los niveles de presión sonora y la influencia del turno y de las incidencias en esos niveles en una unidad neonatal en Rio de Janeiro. Método: Estudio longitudinal, exploratorio, descriptivo, cuyos datos se recopilaron de noviembre de 2021 a enero de 2022. Las variables categóricas se describieron mediante frecuencias absoluta y relativa. Para verificar la adherencia a la distribución normal se utilizó la prueba de Shapiro-Wilk. Para el análisis de la asociación entre variables de exposición y de resultado se utilizaron las pruebas de Mann-Whitney, Kruskal Wallis y Qui-quadrado. Los resultados de p < 0,05 se consideraron estadísticamente significativos. Resultados: se recolectaron 10.122 registros de decibelios y 56 eventos relacionados con actividades, que ocurrieron predominantemente durante el día. Hubo una variación de 38,6 a 93,1 decibelios (dB). En el 96,3% del período observado, los niveles de presión sonora estuvieron por encima de lo recomendado. Comparando los períodos, el nocturno presentó niveles más bajos (p=0,000). Conclusión: Los niveles de presión sonora registrados están por encima de lo recomendado para un ambiente seguro(AU)

Design of a Compact Analog Complex Correlator for Millimeter-Wave Radiation Temperature Measurement System.

Human body temperature is a fundamental physiological sign that reflects the state of physical health. It is important to achieve high-accuracy detection for non-contact human body temperature measurement. In this article, a Ka band (32 to 36 GHz) analog complex correlator using the integrated six-port chip is proposed, and a millimeter-wave thermometer system based on the designed correlator is completed for human body temperature measurement. The designed correlator utilizes the six-port technique to achieve large bandwidth and high sensitivity, and miniaturization of the correlator is achieved through an integrated six-port chip. By performing the single-frequency test and the broadband noise measurement on the correlator, we can determine that the dynamic range of input power of the correlator is -70 dBm to -35 dBm, and the correlation efficiency and equivalent bandwidth are 92.5% and 3.42 GHz, respectively. Moreover, the output of the correlator varies linearly with the input noise power, which reveals that the designed correlator is suitable for the field of human body temperature measurement. Then, a handheld thermometer system, with a size of 140 mm × 47 mm × 20 mm, is proposed using the designed correlator, and the measurement results show that the temperature sensitivity of the thermometer is less than 0.2 K.

Evaluation of small-scale touristic coastal town by noise mapping.

Tourism and the city are in a mutual relationship. Tourism affects the city and is affected by the city. In this context, smart environments that focus on the environment and quality of life come to the forefront in ensuring sustainability in tourism. In sustainable smart environments, noise pollution and control are important in terms of producing plan decisions and determining design criteria. In the study, it was aimed to obtain basic data for the measures to reduce and distribute the noise effect by mapping the noise caused by tourism density in Amasra, which is a small-scale touristic coastal town. In this context, noise maps were created by measuring the noise levels caused by tourism density for the city of Amasra, which is a touristic coastal settlement. In order to determine the noise levels, a total of 15 points were randomly selected, taking into account the proximity to urban uses such as hotels and restaurants as well as urban units such as avenues, streets, open spaces, or squares, provided that they are from various places in the city. Measurements were made regularly on weekdays and weekends in July. As a result of the data obtained, noise pollution levels for the city of Amasra were mapped for different situations (morning, noon, evening, weekdays, weekend, July general) using the Inverse Distance Weighting method. As a result of the measurements and maps prepared, it has been determined that the noise levels of the areas where the vehicle road, parking lot use, shopping and food and beverage places are located are mainly high. Finally, measures for noise control within the scope of sustainable smart environment were created in the study.

Performance improvement in multi-label thoracic abnormality classification of chest X-rays with noisy labels.

PURPOSE: This study aimed at developing a deep learning-based method for multi-label thoracic abnormality classification on frontal view chest X-ray (CXR). To improve the performance of classification, issues of class imbalance, noisy labels and ensemble of networks are addressed in the paper. METHODS: The experiments were performed on a public dataset called Chest X-ray 14 (CXR14), which includes 112,120 frontal view CXRs from 30,805 patients. We came up with an ensemble learning framework to improve the classification and a noisy label detection method to detect the CXRs with noisy labels. The detected CXRs were reviewed by two board-certificated radiologists in a consensus fashion to evaluate detected noisy labels. The classification was assessed on CXR14 with area under the receiver operating characteristic curve (AUC). RESULTS: Report from the radiologists indicated that detected noisy labels had high possibility to be true positives. A notable improvement from baseline in performance of classification was observed with the ensemble learning framework. After removing the CXRs with detected noisy labels, 8 out of 14 abnormalities improved significantly on CXR14. The suggested framework achieved AUC score of 0.827 on CXR14. CONCLUSION: The methods of this study boost the classification on CXR with awareness of the label noise. Expanded experimental results show that all of them were able to improve multi-label thoracic abnormality classification performance, respectively. A new state-of-the-art is achieved in this study.

Statistical Pass-By for Unattended Road Traffic Noise Measurement in an Urban Environment.

Low-noise surfaces have become a common mitigation action in the last decade, so much so that different methods for feature extraction have been established to evaluate their efficacy. Among these, the Close Proximity Index (CPX) evaluates the noise emissions by means of multiple runs at different speeds performed with a vehicle equipped with a reference tire and with acoustic sensors close to the wheel. However, signals acquired with CPX make it source oriented, and the analysis does not consider the real traffic flow of the studied site for a receiver-oriented approach. These aspects are remedied by Statistical Pass-By (SPB), a method based on sensor feature extraction with live detection of events; noise and speed acquisitions are performed at the roadside in real case scenarios. Unfortunately, the specific SPB requirements for its measurement setup do not allow an evaluation in urban context unless a special setup is used, but this may alter the acoustical context in which the measurement was performed. The present paper illustrates the testing and validation of a method named Urban Pass-By (U-SPB), developed during the LIFE NEREiDE project. U-SPB originates from standard SPB, exploits unattended measurements and develops an in-lab feature detection and extraction procedure. The U-SPB extends the evaluation in terms of before/after data comparison of the efficiency of low-noise laying in an urban context while combining the estimation of long-term noise levels and traffic parameters for other environmental noise purposes, such as noise mapping and action planning.

Impact of ROI Size on the Accuracy of Noise Measurement in CT on Computational and ACR Phantoms.

Background: The effect of region of interest (ROI) size variation on producing accurate noise levels is not yet studied. Objective: This study aimed to evaluate the influence of ROI sizes on the accuracy of noise measurement in computed tomography (CT) by using images of a computational and American College of Radiology (ACR) phantoms. Material and Methods: In this experimental study, two phantoms were used, including computational and ACR phantoms. A computational phantom was developed by using Matlab R215a software (Mathworks Inc., Natick, MA Natick, MA) with a homogeneously +100 Hounsfield Unit (HU) value and an added-Gaussian noise with various levels of 5, 10, 25, 50, 75, and 100 HU. The ACR phantom was scanned with a Philips MX-16 slice CT scanner in different slice thicknesses of 1.5, 3, 5, and 7 mm to obtain noise variation. Noise measurement was conducted at the center of the phantom images and four locations close to the edge of the phantom images using different ROI sizes from 3 × 3 to 41 × 41 pixels, with an increased size of 2 × 2 pixels. Results: The use of a minimum ROI size of 21 × 21 pixels shows noise in the range of ± 5% ground truth noise. The measured noise increases above the ± 5% range if the used ROI is smaller than 21 × 21 pixels. Conclusion: A minimum acceptable ROI size is required to maintain the accuracy of noise measurement with a size of 21 × 21 pixels.

Area Noise Assessment at Surface Stone, Sand, and Gravel Mines: Application for Reducing Worker Noise Exposure.

Repeated noise exposure and occupational hearing loss are common health problems across industries and especially within the mining industry. Large mechanized processes, blasting, grinding, drilling, and work that is often in close quarters put many miners at an increased risk of noise overexposure. In stone, sand, and gravel mining, noise is generated from a variety of sources, depending on the type of ore being mined as well as the final consumer product provided by that mine. Depending on the source of noise generation, different strategies to reduce and avoid that noise should be implemented. The National Institute for Occupational Safety and Health (NIOSH) has evaluated the noise profile at three operational surface stone, sand, and gravel mines. A-weighted sound level meter data as well as phase array beamforming data were collected throughout the mines in areas with high noise exposure or high personnel foot or vehicle traffic. Sound level meter data collected on a grid pattern was used to develop sound profiles of the working areas. These sound contour maps as well as phase array beamforming plots were provided to the mines as well as guidance to modify work areas or personnel traffic to reduce noise exposure.

Impact of improved spatial resolution on radiomic features using photon-counting-detector CT.

Radiomics is a promising mathematical tool for characterizing disease and predicting clinical outcomes from radiological images such as CT. Photon-counting-detector (PCD) CT provides improved spatial resolution and dose efficiency relative to conventional energy-integrating-detector CT systems. Since improved spatial resolution enables visualization of smaller structures and more details that are not typically visible at routine resolution, it has a direct impact on textural features in CT images. Therefore, it is of clinical interest to quantify the impact of the improved spatial resolution on calculated radiomic features and, consequently, on sample classification. In this work, organic samples (zucchini, onions, and oranges) were scanned on both clinical PCD-CT and EID-CT systems at two dose levels. High-resolution PCD-CT and routine-resolution EID-CT images were reconstructed using a dedicated sharp kernel and a routine kernel, respectively. The noise in each image was quantified. Fourteen radiomic features of relevance were calculated in each image for each sample and compared between the two scanners. Radiomic features were plotted pairwise to evaluate the resulting cluster separation of the samples by their type between PCD-CT and EID-CT. Thirteen out of 14 studied radiomic features were notably changed by the improved resolution of the PCD-CT system, and the cluster separation was better when assessing features derived from PCD-CT. These results show that features derived from high-resolution PCD-CT, which are subject to higher noise compared to EID-CT, may impact radiomics-based clinical decision making.

Assessment of in-cabin noise of wide-body aircrafts.

The aviation industry has seen dramatic growth over the decades till the recent disruption due to the COVID-19 pandemic. Moreover, long-haul routes with a distance of more than 4000 km are common for major airlines worldwide. Therefore, aircraft cabin noise assessment is essential, especially in long-haul flights, for passenger and flight crew health wellness. In this paper, the cabin noise of five wide-body aircraft, namely Airbus A330-300ER, A350-900, A380-800, and Boeing B777-200ER and B787-900, was recorded using a calibrated in-house developed smartphone application. The sound pressure levels of in-cabin noise have been measured on two different decibel scales, namely, A-weighted [dB(A)] and C-weighted scales [dB(C)]. The sound pressure levels of Airbus A380-800 were lowest among selected models, while the in-cabin pressure level values of Airbus A350-900 were maximum. However, the difference in decibel levels between the aircraft is minimal as it is within 3 dB.

[Investigation and analysis of underground noise in Sichuan coal mines].

Objective: To understand the harm degree of underground noise and provide basis for noise control. Methods: In November 2019, 13 typical coal mines in Sichuan Province were selected as the research objects, and a total of 1203 sites and 609 jobs of noise exposure were investigated. Results: The noise intensity P75 >80 dB (A) was measured. The noise intensity of the inspection place of the air compressor is >86 dB (A) , the noise intensity of the inspection place of the gas drainage and the operation place of the main fan is between 80-85 dB (A) . Conclusion: Besides the harm of dust, noise exposure should also be paid attention to, and the measures of sound absorption and sound insulation should be taken or personal protection should be strengthened.

Síntomas de hipoacusia y exposición al ruido recreativo en jóvenes universitarios, Barranquilla, Colombia / Hearing loss symptoms and leisure noise exposure in university students in Barranquilla, Colombia

RESUMEN Objetivo Investigar la participación de estudiantes universitarios en actividades de ocio productoras de ruido y la relación entre los niveles de exposición semanal al ruido recreativo y síntomas de hipoacusia auto reportados, en la ciudad de Barranquilla, Colombia. Método Se realizó un estudio transversal mediante encuesta virtual, basada en el Cuestionario de Exposición al Ruido, más 11 preguntas de síntomas auditivos, a una muestra aleatoria de 730 sujetos. El nivel de exposición semanal al ruido recreativo se estimó a partir del tiempo dedicado al total de actividades recreativas reportadas por los participantes y su evaluación subjetiva de la intensidad de ruido producida por cada actividad, transformada en niveles de ruido continuo equivalente. La asociación entre la exposición al ruido recreativo y la presencia de síntomas de hipoacusia se analizó mediante la prueba de Chi-cuadrado. Resultados El 93% de los participantes manifestó al menos un síntoma de hipoacusia y la mitad reportó cuatro o más. El síntoma más frecuente de hipoacusia asociada al ruido fue el tinnitus (72%). El 55% tenía una exposición semanal de ruido por encima de 85 dBA y en éstos la prevalencia de síntomas de hipoacusia fue mayor (p < 0.05). Conclusión Se sugiere la presencia de deterioro auditivo en gran parte la población universitaria, asociado con altas dosis de exposición semanal al ruido recreativo. Es necesario fortalecer los programas de promoción de la salud auditiva en la academia, y desde los servicios de salud, la valoración objetiva y periódica de la audición.

ABSTRACT Purpose The aim of this study was to investigate the total weekly exposure to leisure noise among university students and to assess its association with self-reported symptoms of hypoacusis. Methods This is a cross-sectional survey. An online questionnaire based on the "Noise Exposure Questionnaire", plus 11 questions regarding hearing loss were sent to 730 randomly selected students. Participants self-reported time spent on different leisure noise activities and their subjective evaluation of the loudness of these activities, converted into equivalent noise levels, were used to estimate weekly noise exposure levels that were compared to occupational noise limits (> 85 dBA = hazardous). Inference statistics was applied to relate hearing symptoms and "likely or having some degree of hearing loss" with hazardous weekly leisure noise exposure levels. Results Ninety-three percent of the participants reported at least one hypoacusis symptom. The most frequent sound-related ear symptom was tinnitus (72%). Fifty-five percent of the individuals presented weekly exposure to noise >85 dBA. Symptoms of hearing loss were more prevalent in those exposed to weekly noise levels >85 dBA. Conclusion This study suggests that there may be hearing loss caused by exposure to high levels of leisure noise in a large part of the study population. Health promotion of hearing conservation should be emphasized at university level. Objective repeated measurement of hearing acuity should be part of integral health services for the youth population.

Investigation and analysis of underground noise in Sichuan coal mines / 中华劳动卫生职业病杂志

Objective: To understand the harm degree of underground noise and provide basis for noise control. Methods: In November 2019, 13 typical coal mines in Sichuan Province were selected as the research objects, and a total of 1203 sites and 609 jobs of noise exposure were investigated. Results: The noise intensity P75 >80 dB (A) was measured. The noise intensity of the inspection place of the air compressor is >86 dB (A) , the noise intensity of the inspection place of the gas drainage and the operation place of the main fan is between 80-85 dB (A) . Conclusion: Besides the harm of dust, noise exposure should also be paid attention to, and the measures of sound absorption and sound insulation should be taken or personal protection should be strengthened.

Analysis of Magnetic Nondestructive Measurement Methods for Determination of the Degradation of Reactor Pressure Vessel Steel.

Nondestructive magnetic measurement methods can be successfully applied to determine the embrittlement of nuclear pressure vessel steel caused by neutron irradiation. It was found in previous works that reasonable correlation could be obtained between the nondestructively measured magnetic parameters and destructively determined ductile-to-brittle transition temperature. However, a large scatter of the measurement points was detected even in the cases of the non-irradiated reference samples. The reason for their scattering was attributed to the local inhomogeneity of material. This conclusion is verified in the present work by applying three different magnetic methods on two sets of Charpy samples made of two different reactor steel materials. It was found that by an optimal magnetic pre-selection of samples, a good, linear correlation can be found between magnetic parameters as well as the ductile-to-brittle transition temperature with low scattering of points. This result shows that neutron irradiation embrittlement depends very much on the local material properties.

Comparative UAV Noise-Impact Assessments through Survey and Noise Measurements.

Possibilities to use unmanned aerial vehicles (UAVs) are rapidly growing. With the development of battery technologies, communication, navigation, surveillance, and autonomous systems in general, many UAVs are expected to operate at relatively low altitudes. Thus, the problem of UAV noise impact on human health and well-being will be more pronounced. In this paper, we conducted noise measurements of two UAVs of different performance (quadrotor and hexarotor) in flying up and down, hovering, and overflight procedures. Respondents of good hearing who were confirmed by audiogram measurement and had participated in the survey during UAV noise measurement gave their subjective assessments on the UAV noise perception. UAV noise measurements and subjective respondents' assessments were analysed and related. UAV noise analysis showed that the parameters measured at the same measurement point for the hexarotor were higher than those for the quadrotor in flying up and down and flying-over procedures. Low frequency noise was present in the noise spectrum of both drones. Participants were able to distinguish between the noise of UAVs and had a generally more negative experience with the hexarotor. Regardless of the noise perception, more than 80% of the respondents believe there are more pros than cons for UAV introduction into everyday life.

A Comparative Study of the Methods to Assess Occupational Noise Exposures of Fish Harvesters.

BACKGROUND: Noise-induced hearing loss is a well-known occupational disease that affects many fish harvesters from many fisheries worldwide, whose risk factor is prolonged exposure to hazardous noise levels. To date, academic research activities and regulatory bodies have not provided any comparative analysis among the existing methods to assess noise exposure levels of fish harvesters. This paper provides a comparison of four relevant assessment methods of noise exposure, examining the results of a measurement campaign performed onboard small fishing vessels from Newfoundland and Labrador. METHODS: We traveled onboard 11 vessels engaged in multiple fisheries from Newfoundland and Labrador and performed extensive noise exposure surveys using the simplified International Maritime Organization method, the full-day measurement method, and the two methods provided by ISO 9612:2009, the task-based method and job-based method (JBM). RESULTS: The results showed that the four methods yield similar values when the noise components are dominated by the engine and auxiliaries (steady-state sources); when noise components are dominated by the fishing gear, task-based method and the simplified International Maritime Organization method estimates are less accurate than JBM, using full-day measurements as baseline. CONCLUSION: The JBM better assesses noise exposure in small-scale fisheries, where noise exposure has significant variance and uncertainties on the exposure levels are higher.

Land use regression modelling of community noise in São Paulo, Brazil.

Noise pollution has negative health consequences, which becomes increasingly relevant with rapid urbanization. In low- and middle-income countries research on health effects of noise is hampered by scarce exposure data and noise maps. In this study, we developed land use regression (LUR) models to assess spatial variability of community noise in the Western Region of São Paulo, Brazil.We measured outdoor noise levels continuously at 42 homes once or twice for one week in the summer and the winter season. These measurements were integrated with various geographic information system variables to develop LUR models for predicting average A-weighted (dB(A)) day-evening-night equivalent sound levels (Lden) and night sound levels (Lnight). A supervised mixed linear regression analysis was conducted to test potential noise predictors for various buffer sizes and distances between home and noise source. Noise exposure levels in the study area were high with a site average Lden of 69.3 dB(A) ranging from 60.3 to 82.3 dB(A), and a site average Lnight of 59.9 dB(A) ranging from 50.7 to 76.6 dB(A). LUR models had a good fit with a R2 of 0.56 for Lden and 0.63 for Lnight in a leave-one-site-out cross validation. Main predictors of noise were the inverse distance to medium roads, count of educational facilities within a 400 m buffer, mean Normalized Difference Vegetation Index (NDVI) within a 100 m buffer, residential areas within a 50 m (Lden) or 25 m (Lnight) buffer and slum areas within a 400 m buffer. Our study suggests that LUR modelling with geographic predictor data is a promising and efficient approach for noise exposure assessment in low- and middle-income countries, where noise maps are not available.

A proposal for producing calculated noise mapping defining the sound power levels of roads by street stratification.

The European Noise Directive proposes using strategic noise maps as tools to assess populations affected by environmental noise. It recommends using computational methods instead of in situ measurements when possible. A sound source's emission power is an important factor in the calculation of noise indicators. For traffic noise, this parameter is usually defined based on vehicle flow considering an emission spectrum that depends on the type of vehicle and its speed. This study analysed the possibility of using the categorisation method to propose an alternative method of defining a sound source's emission power to develop noise maps. This was accomplished using previously published values of the emission power per unit length. Another method is also proposed that estimates traffic flows. To verify their estimation capacity, the results of both methods were compared with the values obtained from in situ measurements. The results demonstrated similar uncertainties in both methods and were in the range of expected average uncertainties compared to the results obtained by calculating a noise map with the measured experimental values. In particular, for the differences between calculations and measurements, in absolute values, the mean uncertainties were approximately 2 dBA in estimating different long-term noise indicators. For the differences, the mean of the uncertainties obtained via the categorisation method did not present significant differences for the null value for all the analysed noise indicators. Street stratification is a rapid and low-cost approach for road traffic noise mapping without increasing uncertainties.

Review of Low-Frequency Noise Properties of High-Power White LEDs during Long-Term Aging.

Low-frequency noise investigation is a highly sensitive and very informative method for characterization of white nitride-based light-emitting diodes (LEDs) as well as for the evaluation of their degradation. We present a review of quality and reliability investigations of high-power (1 W and 3 W) white light-emitting diodes during long-term aging at the maximum permissible forward current at room temperature. The research was centered on the investigation of blue InGaN and AlInGaN quantum wells (QWs) LEDs covered by a YAG:Ce3+ phosphor layer for white light emission. The current-voltage, light output power, and low-frequency noise characteristics were measured. A broadband silicon photodetector and two-color (blue and red) selective silicon photodetectors were used for the LED output power detection, which makes it possible to separate physical processes related to the initial blue light radiation and the phosphor luminescence. Particular attention was paid to the measurement and interpretation of the simultaneous cross-correlation coefficient between electrical and optical fluctuations. The presented method enables to determine which part of fluctuations originates in the quantum well layer of the LED. The technique using the two-color selective photodetector enables investigation of changes in the noise properties of the main blue light source and the phosphor layer during the long-term aging.

Towards the Interpretation of Sound Measurements from Smartphones Collected with Mobile Crowdsensing in the Healthcare Domain: An Experiment with Android Devices.

The ubiquity of mobile devices fosters the combined use of ecological momentary assessments (EMA) and mobile crowdsensing (MCS) in the field of healthcare. This combination not only allows researchers to collect ecologically valid data, but also to use smartphone sensors to capture the context in which these data are collected. The TrackYourTinnitus (TYT) platform uses EMA to track users' individual subjective tinnitus perception and MCS to capture an objective environmental sound level while the EMA questionnaire is filled in. However, the sound level data cannot be used directly among the different smartphones used by TYT users, since uncalibrated raw values are stored. This work describes an approach towards making these values comparable. In the described setting, the evaluation of sensor measurements from different smartphone users becomes increasingly prevalent. Therefore, the shown approach can be also considered as a more general solution as it not only shows how it helped to interpret TYT sound level data, but may also stimulate other researchers, especially those who need to interpret sensor data in a similar setting. Altogether, the approach will show that measuring sound levels with mobile devices is possible in healthcare scenarios, but there are many challenges to ensuring that the measured values are interpretable.