Microphone array speech enhancement algorithm uses temporal and spatial informa- tion to improve the performance of speech noise reduction significantly. By combining noise estimation algorithm with microphone array speech enhancement, the accuracy of noise estimation is improved, and the computation is reduced. In traditional noise es- timation algorithms, the noise power spectrum is not updated in the presence of speech, which leads to the delay and deviation of noise spectrum estimation. An optimized im- proved minimum controlled recursion average speech enhancement algorithm, based on a microphone matrix is proposed in this paper. It consists of three parts. The first part is the preprocessing, divided into two branches: the upper branch enhances the speech signal, and the lower branch gets the noise. The second part is the optimized improved minimum controlled recursive averaging. The noise power spectrum is updated not only in the non-speech segments but also in the speech segments. Fi- nally, according to the estimated noise power spectrum, the minimum mean-square error log-spectral amplitude algorithm is used to enhance speech. Testing data are from TIMIT and Noisex-92 databases. Short-time objective intelligibility and seg- mental signal-to-noise ratio are chosen as evaluation metrics. Experimental results show that the proposed speech enhancement algorithm can improve the segmental signal-to-noise ratio and short-time objective intelligibility for various noise types at different signal-to-noise ratio levels.
{"title":"Microphone array speech enhancement based on optimized IMCRA","authors":"Qiuying Li, Tao Zhang, Yanzhang Geng, Zhenke Gao","doi":"10.3397/1/376944","DOIUrl":"https://doi.org/10.3397/1/376944","url":null,"abstract":"Microphone array speech enhancement algorithm uses temporal and spatial informa- tion to improve the performance of speech noise reduction significantly. By combining noise estimation algorithm with microphone array speech enhancement, the accuracy of noise estimation is improved, and\u0000 the computation is reduced. In traditional noise es- timation algorithms, the noise power spectrum is not updated in the presence of speech, which leads to the delay and deviation of noise spectrum estimation. An optimized im- proved minimum controlled recursion average speech enhancement\u0000 algorithm, based on a microphone matrix is proposed in this paper. It consists of three parts. The first part is the preprocessing, divided into two branches: the upper branch enhances the speech signal, and the lower branch gets the noise. The second part is the optimized improved minimum\u0000 controlled recursive averaging. The noise power spectrum is updated not only in the non-speech segments but also in the speech segments. Fi- nally, according to the estimated noise power spectrum, the minimum mean-square error log-spectral amplitude algorithm is used to enhance speech. Testing\u0000 data are from TIMIT and Noisex-92 databases. Short-time objective intelligibility and seg- mental signal-to-noise ratio are chosen as evaluation metrics. Experimental results show that the proposed speech enhancement algorithm can improve the segmental signal-to-noise ratio and short-time\u0000 objective intelligibility for various noise types at different signal-to-noise ratio levels.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43088634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roberto Zárate Espinosa, J. Poblet-Puig, Martín Ortega Breña, Marcelo López Parra
The sources of noise and vibration of a refrigerator are characterized by means of laboratory measurements. Three different elements are considered: compressor, evaporator fan, and condenser fan. Both the radiated acoustic energy and the mechanical power injected to the refrigerator structure are measured. Acoustic intensity maps on the refrigerator faces at different frequencies are also provided They are helpful in visualizing the more problematic zones in terms of noise emis- sion. The devices are tested in vacuo or working inside the refrigerator. The provided information can be used as input data for vibroacoustic simulation models such as statistical energy analysis. It is also of interest in order to improve the refrigerator acoustic design.
{"title":"Case study: Experimental characterization of noise and vibration sources in a refrigerator","authors":"Roberto Zárate Espinosa, J. Poblet-Puig, Martín Ortega Breña, Marcelo López Parra","doi":"10.3397/1/376945","DOIUrl":"https://doi.org/10.3397/1/376945","url":null,"abstract":"The sources of noise and vibration of a refrigerator are characterized by means of laboratory measurements. Three different elements are considered: compressor, evaporator fan, and condenser fan. Both the radiated acoustic energy and the mechanical power injected to the refrigerator\u0000 structure are measured. Acoustic intensity maps on the refrigerator faces at different frequencies are also provided They are helpful in visualizing the more problematic zones in terms of noise emis- sion. The devices are tested in vacuo or working inside the refrigerator. The provided information\u0000 can be used as input data for vibroacoustic simulation models such as statistical energy analysis. It is also of interest in order to improve the refrigerator acoustic design.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46663311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuichi Sakamoto, Kohei Il, Ibuki Katayama, Kyosuke Suzuki
A structure that possesses a continuous pore space packed with a granular material exhibits acoustic characteristics based on the principle similar to that of a porous material. Such a structure is used in low-noise pavement and ballast track. Therefore, predicting the sound absorption characteristics of a clearance generated in a granular material from the particle diameter and the physical property of gas is useful for engineering. This article deals with two packing models, namely, the simple cubic lattice model and the hexagonal lattice model, to measure the sound absorption coefficient of the structure packed with a granular material whose particle diameter is a few mm. Furthermore, a simple and accurate theoretical analysis that uses a one-dimensional transfer matrix method, which does not require numerous parameters, was performed. Comparing experimental values, when the particle diameter of the granular material was 4 mm, the percentage of the boundary layer in the clearance was moderately larger than when the diameter was 8 mm; therefore, the effect of viscosity on it was larger, and its sound absorption coefficient peak was higher. Moreover, compared with the simple cubic lattice, the hexagonal lattice had a higher percentage of boundary layer in the clearance because of its smaller volume of pore space. Then, the influence of friction due to the viscosity on it was higher, and its sound absorption coefficient peak was higher. In addition, the theoretical values obtained by the proposed analysis method typically matched the experiment values.
{"title":"Measurement and theoretical analysis of sound absorption of simple cubic and hexagonal lattice granules","authors":"Shuichi Sakamoto, Kohei Il, Ibuki Katayama, Kyosuke Suzuki","doi":"10.3397/1/376937","DOIUrl":"https://doi.org/10.3397/1/376937","url":null,"abstract":"A structure that possesses a continuous pore space packed with a granular material exhibits acoustic characteristics based on the principle similar to that of a porous material. Such a structure is used in low-noise pavement and ballast track. Therefore, predicting the sound absorption\u0000 characteristics of a clearance generated in a granular material from the particle diameter and the physical property of gas is useful for engineering. This article deals with two packing models, namely, the simple cubic lattice model and the hexagonal lattice model, to measure the sound absorption\u0000 coefficient of the structure packed with a granular material whose particle diameter is a few mm. Furthermore, a simple and accurate theoretical analysis that uses a one-dimensional transfer matrix method, which does not require numerous parameters, was performed. Comparing experimental values,\u0000 when the particle diameter of the granular material was 4 mm, the percentage of the boundary layer in the clearance was moderately larger than when the diameter was 8 mm; therefore, the effect of viscosity on it was larger, and its sound absorption coefficient peak was higher. Moreover, compared\u0000 with the simple cubic lattice, the hexagonal lattice had a higher percentage of boundary layer in the clearance because of its smaller volume of pore space. Then, the influence of friction due to the viscosity on it was higher, and its sound absorption coefficient peak was higher. In addition,\u0000 the theoretical values obtained by the proposed analysis method typically matched the experiment values.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41418828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A sirocco fan (forward-curved centrifugal fan), including impeller blades and volute, is designed, and the empirical value ranges of several significant design parameters are discussed and summarized fromthe perspective of both aerodynamics and practical structure. Unsteady-flow numerical simulation and radiated sound-field calculation by indirect boundary element method are combined to evaluate its aerodynamic and acoustic performances. Both the discrete noise source from the rotating impeller and broadband noise source from the volute are considered. Obvious flow separation occurs in the flow passage of impeller blades due to large angle of attack, and the tongue region is the major noise source area due to the small impeller-tongue gap. Therefore, parametric studies for blade installation angle and impeller-tongue gap are performed. Analyses of flow- and sound-field indicate that appropriate reduction of blade geometry incidence angle weakens the flow separation, thereby improving both the aerodynamic and acoustic performances, and reasonable increase of the impeller-tongue gap has a remarkable noise reduction effect for the major noise source area near the volute tongue. The optimized sirocco fan meets the requirement of the industrial project, i.e., the far-field A-weighted sound power level lower than 64.0 dB(A), and achieves larger volume flow rate and total pressure rise. The results also imply that fast steady-flow numerical simulation result is indicative of the acoustic performance to some extent if the acoustic evaluation is urgent. Furthermore, optimization of the key structural parameters in the stage of design is preferable in practical engineering, instead of taking follow-up noise reduction measures.
{"title":"Aerodynamic design and acoustic effect study of key geometric parameters of a sirocco fan","authors":"Chen Wang, Kai Mai, Lanhao Fang, Naitong Liu","doi":"10.3397/1/376940","DOIUrl":"https://doi.org/10.3397/1/376940","url":null,"abstract":"A sirocco fan (forward-curved centrifugal fan), including impeller blades and volute, is designed, and the empirical value ranges of several significant design parameters are discussed and summarized fromthe perspective of both aerodynamics and practical structure. Unsteady-flow numerical\u0000 simulation and radiated sound-field calculation by indirect boundary element method are combined to evaluate its aerodynamic and acoustic performances. Both the discrete noise source from the rotating impeller and broadband noise source from the volute are considered. Obvious flow separation\u0000 occurs in the flow passage of impeller blades due to large angle of attack, and the tongue region is the major noise source area due to the small impeller-tongue gap. Therefore, parametric studies for blade installation angle and impeller-tongue gap are performed. Analyses of flow- and sound-field\u0000 indicate that appropriate reduction of blade geometry incidence angle weakens the flow separation, thereby improving both the aerodynamic and acoustic performances, and reasonable increase of the impeller-tongue gap has a remarkable noise reduction effect for the major noise source area near\u0000 the volute tongue. The optimized sirocco fan meets the requirement of the industrial project, i.e., the far-field A-weighted sound power level lower than 64.0 dB(A), and achieves larger volume flow rate and total pressure rise. The results also imply that fast steady-flow numerical simulation\u0000 result is indicative of the acoustic performance to some extent if the acoustic evaluation is urgent. Furthermore, optimization of the key structural parameters in the stage of design is preferable in practical engineering, instead of taking follow-up noise reduction measures.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48207409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the design of multichannel active noise control filters, the disturbance enhancement phenomenon will sometimes occur, i.e., the resulting sound is enhanced instead of being reduced in some frequency bands, if the control filter is designed to minimize the power of error signals in other frequency bands or across all frequencies. In previous work, a truncated singular value decomposition method was applied to the system autocorrelation matrix to mitigate the disturbance enhancement. Some small singular values and the associated singular vectors are removed, if they are responsible for unwanted disturbance enhancement in some frequency bands. However, some of these removed singular vectors may still contribute to the noise control performance in other frequency bands; thus, a direct truncation will degrade the noise control performance. In the present work, through an additional filtering process, the set of singular vectors that causes the disturbance enhancement is replaced by a set of new singular vectors whose frequency responses are attenuated in the frequency band where disturbance enhancement occurs, while the frequency responses in other frequency bands are unchanged. Compared with truncation approach, the proposed method can maintain the performance in the noise reduction bands, while mitigating the influence in disturbance enhancement bands.
{"title":"Singular vector filtering method for mitigation of disturbance enhancement in multichannel active noise control systems","authors":"Yongjie Zhuang, Xuchen Wang, Yangfan Liu","doi":"10.3397/1/376941","DOIUrl":"https://doi.org/10.3397/1/376941","url":null,"abstract":"In the design of multichannel active noise control filters, the disturbance enhancement phenomenon will sometimes occur, i.e., the resulting sound is enhanced instead of being reduced in some frequency bands, if the control filter is designed to minimize the power of error signals in\u0000 other frequency bands or across all frequencies. In previous work, a truncated singular value decomposition method was applied to the system autocorrelation matrix to mitigate the disturbance enhancement. Some small singular values and the associated singular vectors are removed, if they are\u0000 responsible for unwanted disturbance enhancement in some frequency bands. However, some of these removed singular vectors may still contribute to the noise control performance in other frequency bands; thus, a direct truncation will degrade the noise control performance. In the present work,\u0000 through an additional filtering process, the set of singular vectors that causes the disturbance enhancement is replaced by a set of new singular vectors whose frequency responses are attenuated in the frequency band where disturbance enhancement occurs, while the frequency responses in other\u0000 frequency bands are unchanged. Compared with truncation approach, the proposed method can maintain the performance in the noise reduction bands, while mitigating the influence in disturbance enhancement bands.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43160190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sound transmission loss (TL) through mechanically linked aircraft double-walls is studied with a statistical energy analysis method. An overview of the method is given with details on acoustic and structural transfer path analysis. The studied structure is composed of a thick composite sandwich panel representative of a skin panel, lined with an acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a thin composite sandwich lining panel representative of a trim panel. Two types of vibration isolators are considered: a soft and rigid mechanical link. Various experimental methods were used to assess the accuracy of this model. This study shows the robustness of the simple four-pole modeling of isolators, which depends mainly on the importance of correctly determining the experimental dynamic stiffness of typical aircraft vibration isolators. The prediction of the TL while acceptable was, however, found less satisfactory for the soft configuration. This is traced to the uncertainties on the used coupling loss factor. Finally, a transfer path analysis is performed to identify the contribution of each transmission path in the entire frequency range of interest. Results show that non-resonant airborne transmission dominates in low frequencies, the airborne radiation is significant in the critical frequency region of the panels, while the structure-borne radiation increases the noise transmitted in the mid- and high-frequency ranges.
{"title":"Sound transmission paths through a statistical energy analysis model of mechanically linked aircraft double-walls","authors":"Raef Chérif, A. Wareing, N. Atalla","doi":"10.3397/1/376938","DOIUrl":"https://doi.org/10.3397/1/376938","url":null,"abstract":"Sound transmission loss (TL) through mechanically linked aircraft double-walls is studied with a statistical energy analysis method. An overview of the method is given with details on acoustic and structural transfer path analysis. The studied structure is composed of a thick composite\u0000 sandwich panel representative of a skin panel, lined with an acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a thin composite sandwich lining panel representative of a trim panel. Two types of vibration isolators are considered: a soft and rigid\u0000 mechanical link. Various experimental methods were used to assess the accuracy of this model. This study shows the robustness of the simple four-pole modeling of isolators, which depends mainly on the importance of correctly determining the experimental dynamic stiffness of typical aircraft\u0000 vibration isolators. The prediction of the TL while acceptable was, however, found less satisfactory for the soft configuration. This is traced to the uncertainties on the used coupling loss factor. Finally, a transfer path analysis is performed to identify the contribution of each transmission\u0000 path in the entire frequency range of interest. Results show that non-resonant airborne transmission dominates in low frequencies, the airborne radiation is significant in the critical frequency region of the panels, while the structure-borne radiation increases the noise transmitted in the\u0000 mid- and high-frequency ranges.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42307189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Impedance tube method is widely used to measure acoustic properties of materials. Although this method yields reliable acoustic properties for soft textured materials, uncertainty levels of measured acoustic properties for hard materials, including biocomposites, can be quite large, mainly due to uncertain mounting conditions. Here, the effects of mounting conditions on the acoustic properties of biocomposites in an impedance tube are investigated. First, nominally identical biocomposite samples with a diameter equal to the inner diameter of impedance tube are manufactured and their acoustic properties are determined. As hard materials practically cause fitting problems in the impedance tube, the diameters of samples are reduced, as in practice, by small amounts and acoustic properties of modified samples are determined. Furthermore, in order to match the diameters of samples to the inner diameter of impedance tube, different materials such as tape, petroleum jelly and cotton are applied around samples to close the air gap between the samples and the tube's inner wall. All the results are compared, and the uncertainty levels caused by different mounting conditions on the acoustic properties of biocomposites are identified. The results show that the transmission loss (TL) measurements are dramatically affected by the mounting conditions while the sound absorption conditions are less sensitive to the mounting conditions. The deviations in the measured TL levels are highest for the samples with tape and wax (10–15 dB). On the other hand, the deviations in the measured sound absorption coefficients are highest for the samples with cotton and tape (1–2%).
{"title":"Identification of uncertainty levels of acoustic properties of biocomposites under different mounting conditions in impedance tube tests","authors":"H. Koruk, Y. Saygili, Garip Genc, K. Sanliturk","doi":"10.3397/1/376936","DOIUrl":"https://doi.org/10.3397/1/376936","url":null,"abstract":"Impedance tube method is widely used to measure acoustic properties of materials. Although this method yields reliable acoustic properties for soft textured materials, uncertainty levels of measured acoustic properties for hard materials, including biocomposites, can be quite large,\u0000 mainly due to uncertain mounting conditions. Here, the effects of mounting conditions on the acoustic properties of biocomposites in an impedance tube are investigated. First, nominally identical biocomposite samples with a diameter equal to the inner diameter of impedance tube are manufactured\u0000 and their acoustic properties are determined. As hard materials practically cause fitting problems in the impedance tube, the diameters of samples are reduced, as in practice, by small amounts and acoustic properties of modified samples are determined. Furthermore, in order to match the diameters\u0000 of samples to the inner diameter of impedance tube, different materials such as tape, petroleum jelly and cotton are applied around samples to close the air gap between the samples and the tube's inner wall. All the results are compared, and the uncertainty levels caused by different mounting\u0000 conditions on the acoustic properties of biocomposites are identified. The results show that the transmission loss (TL) measurements are dramatically affected by the mounting conditions while the sound absorption conditions are less sensitive to the mounting conditions. The deviations in the\u0000 measured TL levels are highest for the samples with tape and wax (10–15 dB). On the other hand, the deviations in the measured sound absorption coefficients are highest for the samples with cotton and tape (1–2%).","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44964267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Underwater acoustic detection sensors are mounted on the outside of the submarine; the acoustic window for protecting these sensors must be structurally robust while also minimizing any deterioration of sensor's sound detection performance. These two conditions are typically satisfied simultaneously by using composite materials with acoustic window materials. However, since such composite material is manufactured by laminating fibers, there is the probability that delamination occurs, in which an air layer is formed inside, due to manufacturing process errors. Delamination inside the acoustic window degrades the sensor's acoustic performance and results in a failure of military operations. In the case of composites composed of sandwich structures located in the central part, the possibility of internal delamination is higher than in a single composite material. Therefore, it is very important to discriminate the presence or absence of internal delamination after producing an acoustic window. This article uses numerical and analytical methods to determine the internal delamination of the acoustic window fabricated with a sandwich structure. In addition, the results were analyzed and compared through ultrasonic measurement and acoustic transmission loss test.
{"title":"Prediction and measurement of acoustic transmission loss of acoustic window with composite sandwich structure","authors":"C. M. Lee, K. Jeon, B. Jung, Y. M. Lee, M. Kang","doi":"10.3397/1/376939","DOIUrl":"https://doi.org/10.3397/1/376939","url":null,"abstract":"Underwater acoustic detection sensors are mounted on the outside of the submarine; the acoustic window for protecting these sensors must be structurally robust while also minimizing any deterioration of sensor's sound detection performance. These two conditions are typically satisfied\u0000 simultaneously by using composite materials with acoustic window materials. However, since such composite material is manufactured by laminating fibers, there is the probability that delamination occurs, in which an air layer is formed inside, due to manufacturing process errors. Delamination\u0000 inside the acoustic window degrades the sensor's acoustic performance and results in a failure of military operations. In the case of composites composed of sandwich structures located in the central part, the possibility of internal delamination is higher than in a single composite material.\u0000 Therefore, it is very important to discriminate the presence or absence of internal delamination after producing an acoustic window. This article uses numerical and analytical methods to determine the internal delamination of the acoustic window fabricated with a sandwich structure. In addition,\u0000 the results were analyzed and compared through ultrasonic measurement and acoustic transmission loss test.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49030501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Verification and validation represent an important procedure for model-based systems engineering design processes. One of the crucial tasks for verification and validation is to test whether the control system has reached performance limit. This is challenging since complicated theories and complex steps are often involved to achieve such an objective; meanwhile, the state of the art for testing performance limit requires iterative procedures. A simple and one-off experimental design for telling whether a control system reaches its performance limit is thus necessitated. This article introduces a remarkable test criterion for fulfilling the requirement. Both theoretical foundation and experiment design procedures are presented. Numerical examples are illustrated for the proposed method, where it is also shown that the simple method can be generalized to determining performance limit maps over both frequencies and physical parameters.
{"title":"Experimental design for verification and validation of harmonic vibration control systems","authors":"J. Wang","doi":"10.3397/1/376942","DOIUrl":"https://doi.org/10.3397/1/376942","url":null,"abstract":"Verification and validation represent an important procedure for model-based systems engineering design processes. One of the crucial tasks for verification and validation is to test whether the control system has reached performance limit. This is challenging since complicated theories\u0000 and complex steps are often involved to achieve such an objective; meanwhile, the state of the art for testing performance limit requires iterative procedures. A simple and one-off experimental design for telling whether a control system reaches its performance limit is thus necessitated.\u0000 This article introduces a remarkable test criterion for fulfilling the requirement. Both theoretical foundation and experiment design procedures are presented. Numerical examples are illustrated for the proposed method, where it is also shown that the simple method can be generalized to determining\u0000 performance limit maps over both frequencies and physical parameters.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45411327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Noise is one of the most frequent consequences of traffic. Public transportation systems, such as the Dallas Area Rapid Transit (DART) authority provides various modes of transportation. Even though the availability of commuting service for the public is a boon to communities, mass transit systems are potential sources of excessive sound levels in daily urban life. This article examines the nexus between the transit station facilities of light rail train (LRT) stations and noise implications at both station and neighborhood scales by studying selected LRT stations. A multilevel linear analysis was conducted to understand the degree of train station amenities and neighborhood characteristics that affect sound levels. Using a type II sound pressure level (SPL)meter, sound measurements were obtained during the weekdays and weekends over several weeks. Upon examining the station amenities, and built environment and sociodemographic characteristics of the neighborhood, findings of this comprehensive research reveal significant implications for sound levels. Stations with ticket vending machines and informative message boards include a higher degree of significance on SPLs, while shelters, crew rooms, bike lockers, restrooms, and windshields are significantly and negatively associated with the noise levels. Additionally, neighborhoods with dense roads, higher speed limits, more neighborhood facilities, and a higher number of transit routes have an increased likelihood of noise levels. Recommendations include creating transformative policies for implementation, and approaches addressing noise for transit authorities, transportation engineers, and planners are presented. Planning and engineering aspects of comfort, aesthetics, safety, and public health, as train stations are daily use spaces for commuters and surrounding communities, should also be considered.
{"title":"Station facilities and noise assessment: A multilevel analysis on light rail train stations","authors":"Yalcin Yildirim, D. Allen","doi":"10.3397/1/376933","DOIUrl":"https://doi.org/10.3397/1/376933","url":null,"abstract":"Noise is one of the most frequent consequences of traffic. Public transportation systems, such as the Dallas Area Rapid Transit (DART) authority provides various modes of transportation. Even though the availability of commuting service for the public is a boon to communities, mass\u0000 transit systems are potential sources of excessive sound levels in daily urban life. This article examines the nexus between the transit station facilities of light rail train (LRT) stations and noise implications at both station and neighborhood scales by studying selected LRT stations. A\u0000 multilevel linear analysis was conducted to understand the degree of train station amenities and neighborhood characteristics that affect sound levels. Using a type II sound pressure level (SPL)meter, sound measurements were obtained during the weekdays and weekends over several weeks. Upon\u0000 examining the station amenities, and built environment and sociodemographic characteristics of the neighborhood, findings of this comprehensive research reveal significant implications for sound levels. Stations with ticket vending machines and informative message boards include a higher degree\u0000 of significance on SPLs, while shelters, crew rooms, bike lockers, restrooms, and windshields are significantly and negatively associated with the noise levels. Additionally, neighborhoods with dense roads, higher speed limits, more neighborhood facilities, and a higher number of transit routes\u0000 have an increased likelihood of noise levels. Recommendations include creating transformative policies for implementation, and approaches addressing noise for transit authorities, transportation engineers, and planners are presented. Planning and engineering aspects of comfort, aesthetics,\u0000 safety, and public health, as train stations are daily use spaces for commuters and surrounding communities, should also be considered.","PeriodicalId":49748,"journal":{"name":"Noise Control Engineering Journal","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44280922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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