scholarly journals Low Cost Omnidirectional Sound Source Utilizing a Common Directional Loudspeaker for Impulse Response Measurements

2018 ◽  
Vol 8 (9) ◽  
pp. 1703 ◽  
Author(s):  
Nikolaos Papadakis ◽  
Georgios Stavroulakis
Keyword(s):  
Standard Deviation ◽  
Impulse Response ◽  
Sound Source ◽  
Mean Absolute Error ◽  
Low Cost ◽  
Absolute Error ◽  
Primary Method ◽  
Reverberation Time ◽  
Impulse Responses ◽  
Acoustic Parameters

Alternative low-cost sources (e.g., balloons, gun fires) are used for impulse response measurements when a dodecahedron speaker is not available. This study sets to explore the applicability of a method utilizing a common directional loudspeaker as a sound source. For this purpose measurements were performed in three spaces with three different common directional loudspeakers. Different placements of the loudspeakers were performed (twelve positions similar to the twelve positions of the faces of a dodecahedron speaker, different rotations of the loudspeakers for a total sum of twenty six and fourteen positions). The impulse responses obtained were added up creating a single impulse response for each case. Comparisons of the acoustic parameters measured with the proposed method and with a dodecahedron speaker are presented and suggest the expected mean absolute error and standard deviation for similar measurements. Reverberation time measurements show a mean absolute error of less than 0.08 s, as compared with measurements with a dodecahedron speaker. The proposed method can be the primary method for measuring impulse responses when a dodecahedron speaker is not available. Suggested improvements may lead to better omnidirectionality as compared with a dodecahedron loudspeaker, and set the method applicable to be utilized for auralization purposes.

scholarly journals A Novel Method for Estimating Throwing Speed in Handball using a Wearable Device

2020 ◽  
Author(s):  
Sebastian D Skejø ◽  
Jesper Bencke ◽  
Merete Møller ◽  
Henrik Sørensen
Keyword(s):  
Cross Validation ◽  
Prediction Models ◽  
Mean Absolute Error ◽  
Low Cost ◽  
Absolute Error ◽  
Shoulder Injuries ◽  
Specific Load ◽  
Cheap Method ◽  
Novel Method ◽  
3D Motion Capture

Understanding the shoulder-specific load in handball is important for both prevention and rehabilitation of shoulder injuries. The shoulder-specific load is largely a result of the number and speed of throws. However, it is difficult to quantify number and speed of throws in handball due to limitations in the current technology. Therefore, the purpose of this study was to develop a novel method to estimate throwing speed in handball using a low-cost accelerometer-based device. Nineteen experienced handball players each performed 25 throws of varying types while we measured the acceleration of the wrist using the accelerometer and the throwing speed using 3D motion capture. Using cross-validation, we developed four prediction models using combinations of the logarithm of the peak total acceleration, sex and throwing type as the predictor and the throwing speed as the outcome. We found that all models were well-calibrated (mean calibration of all models: 0.0 m/s, calibration slope range: 0.99-1.00) and precise (R2 = 0.71-0.85, mean absolute error = 1.32-1.82 m/s). We conclude that the developed method appear to provide practitioners and researchers with a feasible and cheap method to estimate throwing speeds in handball.

scholarly journals Archaeoacoustic Research of Ljubostinja and Naupara Medieval Monastic Churches

2019 ◽  
Vol 5 (1) ◽  
pp. 274-283
Author(s):  
Zorana Đorđević ◽  
Dragan Novković
Keyword(s):  
Impulse Response ◽  
Sound Source ◽  
Religious Practice ◽  
Orthodox Church ◽  
Architectural Style ◽  
Acoustic Parameters ◽  
Acoustical Properties

AbstractThe overall experience of religious practice is significantly affected by the acoustical properties of temples. Divine service is the most important act in the Orthodox Church, which equally demands intelligibility of speech for preaching and as well as adequate acoustics for Byzantine chanting as a form of a song-prayer. In order to better understand and contribute to unlocking the role of sound in these historical sacral spaces, this paper explores the acoustics of two well-preserved Orthodox churches, from Ljubostinja and Naupara monastery, built in the last building period of medieval Serbia (1371–1459). These represent two types of the Morava architectural style – triconch combined with a developed and compressed inscribed cross, respectively. Using EASERA software, we measured the impulse response for two sound source positions – in the altar and in the southern chanting apse, as the main points from which the Orthodox service is carried out. Thus obtained acoustic parameters (RT, EDT, C50 and STI) were further analysed, pointing out the differences in experiencing sound between naos and narthex, as well as how the position of the sound source influenced the experience of sound. Finally, we compared the results with previous archaeoacoustic research of the churches from the same building period.

scholarly journals Evaluation and Application of a Novel Low-Cost Wearable Sensing Device in Assessing Real-Time PM2.5 Exposure in Major Asian Transportation Modes

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 270
Author(s):  
Wen-Cheng Vincent Wang ◽  
Shih-Chun Candice Lung ◽  
Chun-Hu Liu ◽  
Tzu-Yao Julia Wen ◽  
Shu-Chuan Hu ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Real Time ◽  
Mean Absolute Error ◽  
Low Cost ◽  
Absolute Error ◽  
Laboratory Evaluation ◽  
Sensing System ◽  
Transportation Modes ◽  
Pm2.5 Exposure ◽  
Device Location

Small low-cost sensing (LCS) devices enable assessment of close-to-reality PM2.5 exposures, though their data quality remains a challenge. This work evaluates the precision, accuracy, wearability and stability of a wearable particle LCS device, Location-Aware Sensing System (LASS, with Plantower PMS3003), which is 104 × 66 × 46 mm3 in size and less than 162 g in weight. Real-time particulate matter (PM) exposures in six major Asian transportation modes were assessed. Side-by-side laboratory evaluation of PM2.5 between a GRIMM aerosol spectrometer and sensors yielded a correlation of 0.98 and a mean absolute error of 0.85 µg/m3. LASS readings collected in the summer of 2016 in Taiwan were converted to GRIMM-comparable values. Mean PM2.5 concentrations obtained from GRIMM and converted LASS values of the six different transportation microenvironments were 16.9 ± 11.7 (n = 1774) and 17.0 ± 9.5 (n = 3399) µg/m3, respectively, showing a correlation of 0.93. The average one-hour PM2.5 exposure increments (concentration increase above ambient levels) from converted LASS values for Mass Rapid Transit (MRT), bus, car, scooter, bike and walk were 15.6, 6.7, −19.2, 8.1, 6.1 and 7.1 µg/m3, respectively, very close to those obtained from GRIMM. This work is one of the earliest studies applying wearable particulate matter (PM) LCS devices in exposure assessment in different transportation modes.

The Assessment of Sports Halls – The Analysis of Reverberation Time, Strength and Clarity

2014 ◽  
Vol 899 ◽  
pp. 517-521
Author(s):  
Martin Jedovnický ◽  
Peter Tomašovič
Keyword(s):  
Sound Source ◽  
In Situ Measurement ◽  
Reverberation Time ◽  
Impulse Responses ◽  
Frequency Range ◽  
Time Strength

This article presents the results of analysis of impulse responses which were obtained from in situ measurement in sports hall called Karlovka. The experiment deals with the comparison of two positions of the measuring microphone which had the identical distance from the sound source and the reverberation time was different in the whole frequency range. The attention was focused on the analysis of suitability of Reverberation time RT, Strength G and Clarity C80 to be used for the assessment of sports halls.

scholarly journals Upgraded global mapping information for earth system modelling: an application to surface water depth at the ECMWF

2019 ◽  
Vol 23 (10) ◽  
pp. 4051-4076 ◽  
Author(s):  
Margarita Choulga ◽  
Ekaterina Kourzeneva ◽  
Gianpaolo Balsamo ◽  
Souhail Boussetta ◽  
Nils Wedi
Keyword(s):  
Standard Deviation ◽  
Surface Water ◽  
Lake Water ◽  
Water Surface ◽  
Mean Absolute Error ◽  
Absolute Error ◽  
Ice Formation ◽  
Lake Depth ◽  
Water Surface Temperature ◽  
Error Standard Deviation

Abstract. Water bodies influence local weather and climate, especially in lake-rich areas. The FLake (Fresh-water Lake model) parameterisation is employed in the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) model which is used operationally to produce global weather predictions. Lake depth and lake fraction are the main driving parameters in the FLake parameterisation. The lake parameter fields for the IFS should be global and realistic, because FLake runs over all the grid boxes, and then only lake-related results are used further. In this study new datasets and methods for generating lake fraction and lake depth fields for the IFS are proposed. The data include the new version of the Global Lake Database (GLDBv3) which contains depth estimates for unstudied lakes based on a geological approach, the General Bathymetric Chart of the Oceans and the Global Surface Water Explorer dataset which contains information on the spatial and temporal variability of surface water. The first new method suggested is a two-step lake fraction calculation; the first step is at 1 km grid resolution and the second is at the resolution of other grids in the IFS system. The second new method involves the use of a novel algorithm for ocean and inland water separation. This new algorithm may be used by anyone in the environmental modelling community. To assess the impact of using these innovations, in situ measurements of lake depth, lake water surface temperature and ice formation/disappearance dates for 27 lakes collected by the Finnish Environment Institute were used. A set of offline experiments driven by atmospheric forcing from the ECMWF ERA5 Reanalysis were carried out using the IFS HTESSEL land surface model. In terms of lake depth, the new dataset shows a much lower mean absolute error, bias and error standard deviation compared to the reference set-up. In terms of lake water surface temperature, the mean absolute error is reduced by 13.4 %, the bias by 12.5 % and the error standard deviation by 20.3 %. Seasonal verification of the mixed layer depth temperature and ice formation/disappearance dates revealed a cold bias in the meteorological forcing from ERA5. Spring, summer and autumn verification scores confirm an overall reduction in the surface water temperature errors. For winter, no statistically significant change in the ice formation/disappearance date errors was detected.

scholarly journals Logatome and Sentence Recognition Related to Acoustic Parameters of Enclosures

2017 ◽  
Vol 42 (3) ◽  
pp. 385-394
Author(s):  
Jedrzej Kocinski ◽  
Edward Ozimek
Keyword(s):  
Speech Recognition ◽  
Reverberation Time ◽  
Impulse Responses ◽  
Acoustic Parameters ◽  
Music School ◽  
Sentence Recognition ◽  
Speech Reception ◽  
Middle Range ◽  
Transmission Index ◽  
Speech Transmission

AbstractThe paper deals with relationship between speech recognition and objective parameters of enclosures. Six enclosures were chosen: a church, an assembly hall of a music school, two courtrooms of different volumes, a typical auditorium and a university concert hall. Dirac 4.1 software was used to record impulse responses (IRs) in the chosen measurement points of each enclosure. On this base, the following objective parameters of the enclosure were determined: Reverberation Time (RT), Early Decay Time (EDT), Weighted Clarity (C50) and Speech Transmission Index (STI). A convolution of the IRs with logatome tests and the Polish Sentence Test (PST) was made. Logatome recognition and speech reception threshold (SRT - i.e., SNR yielding 50% speech recognition) were evaluated and their dependence on the objective parameters were determined. Generally a linear relationship between logatome or SRT and RT or EDT was found. However, speech recognition was nonlinearly related (according to psychometric function) to STI values. The most sensitive range of the logatome and sentence recognition relative to STI changes corresponded to the middle range of STI values. Below and above this range, logatome and sentence recognition were much less dependent of STI changes.

scholarly journals Estimating Throwing Speed in Handball Using a Wearable Device

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4925
Author(s):  
Sebastian D. Skejø ◽  
Jesper Bencke ◽  
Merete Møller ◽  
Henrik Sørensen
Keyword(s):  
Cross Validation ◽  
Prediction Models ◽  
Mean Absolute Error ◽  
Low Cost ◽  
Absolute Error ◽  
Specific Load ◽  
Cheap Method ◽  
Novel Method ◽  
3D Motion Capture ◽  
Acceleration Signals

Throwing speed is likely a key determinant of shoulder-specific load. However, it is difficult to estimate the speed of throws in handball in field-based settings with many players due to limitations in current technology. Therefore, the purpose of this study was to develop a novel method to estimate throwing speed in handball using a low-cost accelerometer-based device. Nineteen experienced handball players each performed 25 throws of varying types while we measured the acceleration of the wrist using the accelerometer and the throwing speed using 3D motion capture. Using cross-validation, we developed four prediction models using combinations of the logarithm of the peak total acceleration, sex and throwing type as the predictor and the throwing speed as the outcome. We found that all models were well-calibrated (mean calibration of all models: 0.0 m/s, calibration slope of all models: 1.00) and precise (R2 = 0.71–0.86, mean absolute error = 1.30–1.82 m/s). We conclude that the developed method provides practitioners and researchers with a feasible and cheap method to estimate throwing speed in handball from segments of wrist acceleration signals containing only a single throw.

scholarly journals Modeling Superconducting Critical Temperature of 122-Iron-Based Pnictide Intermetallic Superconductor Using a Hybrid Intelligent Computational Method

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4604
Author(s):  
Oluwatobi Akomolafe ◽  
Taoreed O. Owolabi ◽  
Mohd Amiruddin Abd Rahman ◽  
Mohd Mustafa Awang Kechik ◽  
Mohd Najib Mohd Yasin ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Structural Transformation ◽  
Mean Absolute Error ◽  
Low Cost ◽  
Absolute Error ◽  
Computational Method ◽  
Hole Doping ◽  
Support Vector ◽  
Ionic Radii ◽  
Iron Based

Structural transformation and magnetic ordering interplays for emergence as well as suppression of superconductivity in 122-iron-based superconducting materials. Electron and hole doping play a vital role in structural transition and magnetism suppression and ultimately enhance the room pressure superconducting critical temperature of the compound. This work models the superconducting critical temperature of 122-iron-based superconductor using tetragonal to orthorhombic lattice (LAT) structural transformation during low-temperature cooling and ionic radii of the dopants as descriptors through hybridization of support vector regression (SVR) intelligent algorithm with particle swarm (PS) parameter optimization method. The developed PS-SVR-RAD model, which utilizes ionic radii (RAD) and the concentrations of dopants as descriptors, shows better performance over the developed PS-SVR-LAT model that employs lattice parameters emanated from structural transformation as descriptors. Using the root mean square error (RMSE), coefficient of correlation (CC) and mean absolute error as performance measuring criteria, the developed PS-SVR-RAD model performs better than the PS-SVR-LAT model with performance improvement of 15.28, 7.62 and 72.12%, on the basis of RMSE, CC and Mean Absolute Error (MAE), respectively. Among the merits of the developed PS-SVR-RAD model over the PS-SVR-LAT model is the possibility of electrons and holes doping from four different dopants, better performance and ease of model development at relatively low cost since the descriptors are easily fetched ionic radii. The developed intelligent models in this work would definitely facilitate quick and precise determination of critical transition temperature of 122-iron-based superconductor for desired applications at low cost with experimental stress circumvention.

scholarly journals Inter-Floor Noise Monitoring System for Multi-Dwelling Houses Using Smartphones

2020 ◽  
Vol 12 (12) ◽  
pp. 5065
Author(s):  
Suhyun Kang ◽  
Seungho Kim ◽  
Dongeun Lee ◽  
Sangyong Kim
Keyword(s):  
Noise Source ◽  
Mean Absolute Error ◽  
Low Cost ◽  
Monitoring And Evaluation ◽  
Absolute Error ◽  
Maximum Error ◽  
Sound Level ◽  
Apartment Buildings ◽  
The Mean

The noise between the floors in apartment buildings is becoming a social problem, and the number of disputes related to it are increasing every year. However, laypersons will find it difficult to use the sound level meters because they are expensive, delicate, bulky, etc. Therefore, this study proposes a system to monitor the noise between the floors, that will measure the sound and estimate the location of the noise using the sensors and applications in smartphones. To evaluate how this system can be used effectively within an apartment building, a case study has been performed to verify its validity. The result shows that the mean absolute error (MAE) between the actual noise generating position and the estimated noise source location was measured at 2.8 m, with a minimum error of 1.2 m and a maximum error of 4.3 m. This means that smartphones, in the future, can be used as low-cost monitoring and evaluation devices to measure the noise between the floors in apartment buildings.

scholarly journals The Effects of Adding Pyramidal and Convex Diffusers on Room Acoustic Parameters in a Small Non-Diffuse Room

Acoustics ◽  
2019 ◽  
Vol 1 (3) ◽  
pp. 618-643
Author(s):  
Hassan Azad ◽  
Julie Meyer ◽  
Gary Siebein ◽  
Tapio Lokki
Keyword(s):  
Statistical Analysis ◽  
Large Scale ◽  
Reverberation Time ◽  
Impulse Responses ◽  
Acoustical Parameters ◽  
Acoustic Parameters ◽  
Acoustical Properties ◽  
Measurement Results ◽  
The Difference ◽  
Rectangular Room

This paper presents an investigation of the effects of relatively large-scale pyramidal and convex-shaped diffusers on the acoustical properties of a small non-diffuse rectangular room. Room impulse responses (RIRs) were measured in various room configurations to extract the early decay time (EDT), reverberation time (T20), early-to-late arriving sound ratio (C50), and clarity (C80). The difference between the parameters measured in the empty room were chosen to be the reference, and those measured in other room configurations was calculated. Statistical analysis of the measurement results supplements the investigation to determine whether the coverage and type of diffusers contribute significantly to the variation of the acoustical parameters. The results show that adding diffusers in the room generally decreases EDT as well as T20, and increases C50 as well as C80 for both diffuser types. The statistical analysis shows that the coverage of diffusers significantly contributes to the variation of the acoustical parameters in most conditions (octave band, diffuser type). The effect of the diffuser shape is only significant for some of the conditions (at 4 kHz, the number of diffusers). The data presented demonstrate that in a small non-diffuse room the reverberation can be controlled efficiently by redirecting the sound energy towards the most absorbing surfaces.

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