Kyushu Shinkansen and conventional railway lines run parallel in the areas 5 km north of Kumamoto Station (northern area) and 12 km south of the station (southern area). Following the operation of the Kyushu Shinkansen Line in 2011, the adjacent conventional railway line in the north was elevated, a new station was operated in the south, and large earthquakes struck the Kumamoto area from March to April 2016. Sleep disturbances were compared before and after the interventions and earthquakes based on noise source (Shinkansen and conventional railways), area (northern and southern), and house type (detached and apartment) through socio-acoustic surveys from 2011 to 2017. The Shinkansen railway caused significantly less sleep disturbances in detached houses in the north after compared to before the earthquakes, presumably due to more frequent closures of bedroom windows in northern detached houses following the earthquakes. The Shinkansen railway caused significantly more sleep disturbances in apartments in the south after compared to before the earthquakes, presumably because the Shinkansen slowed down immediately after the earthquakes and returned to normal speed during the survey, suddenly increasing the noise exposure. There was no significant difference in the other six cases investigated. Overall, the interventions may not have caused significant differences in sleep disturbances. This article expands on the congress paper by Morihara et al. presented in the “Community Response to Noise” session at the 52nd International Congress and Exhibition on Noise Control Engineering in Makuhari, Japan, organized by the International Institute of Noise Control Engineering.

Air traffic bans in response to the spread of the coronavirus have changed the sound situation of urban areas around airports. This study aimed to investigate the effect of this unprecedented event on the community response to noise before and after the international flight operation at Tan Son Nhat Airport (TSN) in March 2020. The “before” survey was conducted in August 2019, and the two “after” surveys were conducted in June and September 2020. Structural equation models (SEMs) for noise annoyance and insomnia were developed by linking the questionnaire items of the social surveys. The first effort aimed to achieve a common model of noise annoyance and insomnia, corresponding to the situation before and after the change, respectively. Approximately, 1200 responses were obtained from surveys conducted in 12 residential areas around TSN in 2019 and 2020. The average daily flight numbers observed in August 2019 during the two surveys conducted in 2020 were 728, 413, and 299, respectively. The sound pressure levels of the 12 sites around TSN decreased from 45–81 dB (mean = 64, SD = 9.8) in 2019 to 41–76 dB (mean = 60, SD = 9.8) and 41–73 dB (mean = 59, SD = 9.3) in June and September 2020, respectively. The SEM indicated that the residents’ health was related to increased annoyance and insomnia.

地表面音響特性の広域における空間分布データは，未整備である。そこで，ハイパスペクトル航空画像を用いて地表面をその音響特性に応じて分類する手法を開発する。3 季節に複数種の地表面の音響特性を測定し，実効的流れ抵抗を推定して地表面の状態の分類クラスを決める。教師付き分類手法のMED-SD法を用い，教師スペクトルと適用する画像の撮影季節を12パターンに組み合わせ，分類精度を評価する。最 後に，886 m × 445 mの範囲を分類する。その結果，秋に撮影した航空画像から求めた教師スペクトルが最も分類に適した。これにより，広域の地表面の音響特性を実際の状態に基づき，的確かつ効率的に設定できる可能性が示された。

The change in the self-reported health status of residents associated with the reduced aircraft noise around Tan Son Nhat airport (TSN) after the epidemic outbreak in early 2020 was investigated in three stages. Stage 1 is pre-outbreak when the airport was operating at its highest capacity. Phases 2 and 3 are three months and six months after the stop of international flight operation implemented in March 2020. Data on the residents' health status was obtained from face-to-face interviews. The questionnaire items were composed of Noise annoyance questions using the 11-point ICBEN scale, the Total Health Index, Health and lifestyle questionnaire, Depression Scale revised questionnaire, and questionnaires to identify insomnia, hypertension, and hearing loss. Other factors related to living conditions such as education, income, or housing were also collected as health adjustment factors. The noise levels of phases 2 and 3 were estimated by updating the noise contour map of phase 1 using the TSN airport's operation data in corresponding periods in 2020. This study provided evidence relating to variation of the residents' health status due to the noise situation change.

The travel restrictions caused by the epidemic outbreak in early 2020 worldwide have caused many changes in all aspects of life, especially in the acoustic environment. This study examines the impact of this environmental change at Tan Son Nhat International Airport (TSN), the largest airport in Vietnam, by comparing the situations before and after the airport stopped operating all international flights in March 2020. The after-the-change survey was conducted in 2 phases, June and September 2020, three months and six months after the stop decision. The number of flights observed in August 2019 was 728; this number is 413 and 299 for the two surveys in 2020. The range of noise levels estimated for 12 sites around TSN decreased from 63-81 dB in 2019 to 32-67 dB in June 2020 and 33-69 dB in September 2020. At the same aircraft noise level, the percentage of highly annoyed (% HA) and the percentage of insomnia (%ISM) in the 2020 survey are higher than those in the 2019 survey. The comparison results of reaction to noise before and after the TSN's noise change indicated an increase in negative responses to noise might happen in the increased noise and reduced noise situation.

There have been many arguments about findings of an increase in noise annoyance over time and a recommendation of stricter limits on aircraft noise levels to protect the health of residents around airports. It is crucial to examine if the established exposure–response relationship is suitable for designing future aircraft noise regulations. This study was focused on identifying changes in response to noise over time by comparing community responses from two surveys conducted in 2008 and 2019 at Tân Sơn Nhất (TSN) international airport. Annoyance was found to significantly reduce in 2019 compared to 2008; however, changes in sleep quality were relatively small. Unexpectedly, a gradual increase in the annoyance due to aircraft noise was not found. Results of multiple regression analysis indicated that differences in the reaction of the residents to noise in the two studies were significantly attributed to nonacoustic factors. Noise sensitivity and dissatisfaction with the living environment (e.g., inconvenience in accessing workplace) considerably affect noise annoyance, whereas noise sensitivity, age, and dissatisfaction with the green environment of living areas affect sleep quality. These findings suggest the fulfillment of desired living environment as effective measures for mitigating noise impacts on residents in the vicinity of busy airports.

On Hashima Island (commonly known as Gunkanjima) in Nagasaki, Japan, where Hashima Coal Mine was formally approved as a part of the World Heritage Site, there are many reinforced concrete (RC) structures constructed several decades to a century ago. Continuous evaluation of their deterioration properties generates data regarding historic buildings and helps understand the progress of deterioration in RC buildings. A visual inspection (VI) is generally used for deterioration surveys however, determining the internal deterioration using this method alone is difficult. In this study, the hammering method is used, which analyzes the acoustic characteristics of impact echoes to determine the deterioration condition. The impact sound on the concrete surface is analyzed and compared with the VI results to improve the deterioration investigation accuracy. A steel ball impacts the columns of RC buildings, and the radiated sound from the concrete surface is recorded using a microphone. Next, the sound pressure level at the maximum amplitude of the impact sound is obtained. The above levels are compared with the VI results in general, the worse the visual results, the louder are the levels. On the other hand, although visual results are suitable, some data have higher sound pressure levels. According to a 1/3 octave band analysis, the data having similar sound pressure levels show similar frequency characteristics regardless of the visual results, indicating that such data have similar deterioration properties. These results show that the hammering method can provide information regarding the deterioration of the RC buildings on Hashima that cannot be obtained via the VI alone.

The sounds from childcare facilities are often a cause of noise problems with neighbors. However since the sound power levels of children's play and other sounds in child-care facilities have not become clear, evaluation methods have not been established, making countermeasures difficult. In order to evaluate the noise, it is necessary to model the location of the sound source and the sound power level. We have been developing a sound source identification system that uses multiple Raspberry Pi-based recording devices to estimate the location of a sound source and sound power levels. By using GPS for time synchronization, the system can be distributed and placed without connecting cables, which is expected to expand the measurement area significantly. As a method of estimation, the arrival time difference is calculated by cross-correlation from the signals input to each recording device, and the sound source location is estimated from the calculated arrival time difference and the location information of the device. The effectiveness of this system was verified in an anechoic chamber and outdoor fields.

Noise map provides a basis for land-use and flight path planning to limit the noise impact on residents around airports. This study is one of the first attempts to access an appropriate method to create noise maps for airports in Vietnam. In this study, the L-den around Noi Bai International Airport (NBIA) was predicted by using the Integrated Noise Model (INM) with available Noise-Power-Distance (NPD) data in INM and NPD data of military airplane created based on the field measurement. Besides, to assess the validity of the prediction, the predicted L-den was compared with the measured L-den, which were defined by field measurements conducted at ten residential sites around NBIA in November 2017. The noise levels were estimated with 3 cases: (1) Civil aircraft only, using INM' s NPD; (2) Civil aircraft & military aircraft, using INM' s NPD for military aircraft; (3) Civil aircraft & military aircraft, using measurement-based NPD for military aircraft. By comparing the root mean square error between the predicted and the measured values, it could be found that the prediction in Case 3 is the most consistent with the measured L-den. In other words, the prediction validity was improved by using measurement-based NPD of military aircraft.

In this study, we applied a non-contact mat sensor to measure the body motion and the heart rate (HR) of human examinees during the experiment under different conditions. This mat sensor be able to avoid any restriction of human body movement that may affect the sleeping condition. The obtained HR data from the mat sensor was transformed into LF/HF as an indicator of HRV. Then Structural Equation Modeling was performed to identify of the relation between Environmental factors, the body motion, the HRV and results on subjective feeling of sleep from OSA sleep inventory MA version.

A representative exposure-response relationship for aircraft noise annoyance in Vietnam was established partly based on data obtained from a social survey on community response to aircraft noise carried out around Tan Son Nhat International Airport (TIA), Vietnam's largest airport, in 2008. The question is whether the response to noise changes throughout the time and if the established relationship is suitable for the present consideration for future aircraft noise regulations. This study provided a comparison between the previous survey in 2008 and the recent investigation on noise impact conducted at the same residential areas near TIA in 2019. The average flight number increased from 200 in 2008 to more than 720 in 2019. Accordingly, the day-evening-night noise level (Lden) ranged from 53 to 71 dB and from 63 to 81 in 2008 and 2019, respectively. The percentage of highly annoyed respondents in an area of above 70 dB (Lden) was 52% in the 2008 survey, while this number only 12 percent in the 2019 survey. The residents living in the noisier environment seem to be more tolerant of noise.

Tan Son Nhat International Airport (TIA) is Vietnam's largest airport with more than 700 take-offs and landings per day and is surrounded by densely populated areas of Ho Chi Minh City. A health survey was carried out to investigate the association of aircraft noise with the prevalence of annoyance, insomnia and other risks of physical and mental health problems such as obesity, hypertension, stress, depression and so on in the community living near TIA in August 2019. In total, 502 responses obtained in 12 residential areas including ten target sites which scattered under the landing and take-off route of the airplanes and exposed to different aircraft noise ranging from low to high levels, and two control sites which are not affected by aircraft noise. Out of 294 in the total of 502 respondents exposed to day-evening-night noise levels of above 65 dB. The results of multiple logistic regression analysis showed that aircraft noise significantly affected the prevalence of annoyance but have no direct effect on insomnia and hypertension. The indirect effect of noise on other health indicators was also investigated.

Herein, the effects of changes in acoustic and non-acoustic factors on public health and reactions were assessed using two follow-up investigations; this was achieved after three surveys were conducted on the impact of the step change in noise caused by the increased number of flights at the Noi Bai International Airport in Hanoi (Vietnam) after the new terminal building was opened to the public. Exposure-response relationships established in the follow-up studies were less in number than those established in 2015 after the step change had occurred, and were almost similar to the relationship established in the survey conducted before the step change; however, these relationships were significantly greater than those established in the European Union position paper. Comparisons between respondents with high blood pressure and insomnia ratios at different noise level ranges showed that there is no significant association between ratios of high blood pressure and day-evening-night noise levels; however, an exposure-response relationship was discovered between insomnia and night-time noise levels. Non-acoustic factors such as noise sensitivity, sound insulation capacity of houses, and length of residence were found to curb the respondents' annoyance, insomnia, and high blood pressure. Thus, an improvement in residence quality and a restriction on nighttime flight operation is necessitated.

Heart rate variability (HRV) is the temporal fluctuation of heart rate (HR) and has been often used in the study of autonomic nerve activity of a human body. In this study, we applied a non-contact mat sensor to measure the HRV of human examinees during sleep in order to avoid any restriction of human body movement that may affect the sleeping condition during the experiment. The obtained HR data from the mat sensor was transformed into LF/HF (the ratio of a low frequency factor to a high frequency factor of the power spectrum of the HR) as an indicator of HRV. Then correlation analysis was performed to identify the strength of the relation between environmental factor, the Vital signs including LF/HF, and results from OSA sleep inventory MA version. The most significant correlation was found between the body motion and OSA subjective feeling of sleep.

The rapid development of air transport resulted in increased levels and wider influential scale of noise due to the airport operation. The number of flights operated and the housing conditions at residential areas around Noi Bai International Airport has increased significantly in the past nine years. The exposure noise levels (Lden) at surveyed sites ranged between 48 and 61 dB in 2009, but increased to range between 54 and 76 dB in 2017. General health indicators such as Body Mass Index (BMI), blood pressure, etc. were investigated in two surveys conducted in November 2017 and August 2018. Exposure-response relationships established in the five surveys conducted from 2014 to 2018 were found to be higher than that established in 2009 survey. Comparisons of respondents with high blood pressure and insomnia ratios at different noise exposure level ranges showed that there is no significant association between ratios of hypertension and noise exposure levels (Lden) but a significant exposure-response relationship was found between night-time noise exposure levels and insomnia. This study results suggested that improvement of residence quality and a restriction on nighttime flight operation should be considered to protect health of resident living around airports in Vietnam.

We refer to “Multi-group conversation space (MGCS)” as a space where more than one groups share a space and make conversations within the groups, such as restaurant or café. In this study, we investigated acoustic comfort in MGCS considering speech intelligibility and speech privacy as major factors by conducting acoustic measurements and a questionnaire survey to the customers for four days in an actual café. The volume of background music (BGM) during operating hours was changed each day at three levels of low, middle and high and no BGM. The indoor noise levels were measured at six representative points with six sound level meters hung from the ceiling. The questionnaire consisted of eight items including ease of making conversation, comfort, and atmosphere (lively/relaxed). The customers were asked to answer questions at their table after having their meal or drink and, at the same time, the occupancy of neighboring table and the number of customers in the café were recorded. Results show that the ease of conversation tended to be evaluated better when the volume setting of the BGM was middle level than other settings. Also the impression evaluation varied by gender, age, or seat position and occupancy.

Up until now, in Japan, the dose-response relationship of Shinkansen railway noise has been estimated using measurement-based noise exposure levels as dose value. The noise exposure levels at the house of respondents were calculated by assuming a line sound source and a noise attenuation due to buildings was not considered. In this paper, we propose a noise mapping technique of Shinkansen-railway by using a point sound source model and re-estimate the dose-response relationship of Shinkansen railway noise.

The rapid development of air traffic in Asia along with the urbanization process made the increasing population living around airports exposed to higher noise levels. A noise map is helpful to track the level of change and evaluate the environmental impact due to the airport noise for appropriate countermeasures. This study is one of the first attempts to access an appropriate method to create noise maps for Vietnam in the absence of required data and limited technical means. Field measurements were conducted at Noi Bai International Airport (HNBIA) and Da Nang International Airport (DNIA), which were jointly used by the military and the civil aviation, in November 2017 and August 2018, respectively. Data related to the flight paths and operation of the aircraft were processed and input in the Integrated Noise Model (INM). Particular characteristics of the two airports such as climate conditions, geographical location, and operation of specific military aircraft types caused the difference between Noise-Power-Distance (NPD) data created by field measurement data and available NPD data in INM. The estimated noise levels using INM's existing and measurement-based NPD were compared with field measurement data to clarify the accuracy of the estimation process proposed in this study.

The number of studies on the impact of noise on health is very limited especially for people living around major airports in developing countries. Two surveys on health effects of aircraft noise were conducted at 13 sites around Noi Bai International Airport (HNBIA) in November 2017 and August 2018. The surveyed contents included aircraft noise exposure levels, noise annoyance, sleep disturbance and general health indicators such as Body Mass Index (BMI), blood pressure, etc. Exposure levels were obtained by field measurement and noise map estimation. Community responses were investigated by face-to-face interview. Blood pressure of the respondents was assessed by self-reported method and measurement. Comparisons of respondents with high blood pressure and insomnia ratios at different noise exposure level ranges showed that there is no significant association between ratios of hypertension and noise exposure levels (Lden) but a significant exposure-response relationship was found between night-time noise exposure levels and insomnia. This result suggested that a restriction on nighttime flight operation and a specific regulation for aircraft noise limit should be considered to protect the health of residents living around airports for sustainable and balanced development of air transport in Vietnam.

Noi Bai International Airport (HNBIA) is the second largest airport in Vietnam. Recently, the rapid development of air transport in Vietnam, together with the urbanization of the area around the airport, resulted in increased levels and wider influential scale of noise due to the airport operation. This study summarizes the results of socio-acoustic surveys on community response to noise conducted around NBIA from 2009 to 2018. The number of flights operated at NBIA and the population density at residential areas around the airport has increased significantly in the past nine years. The exposure noise levels (Lden) at surveyed sites ranged between 48 and 61 dB in 2009, but increased to range between 54 and 76 dB in 2017. Exposure-response relationships established in the five surveys conducted from 2014 to 2018 were found to be higher than that established in 2009 survey. Especially, an excess response due to the step-change of noise exposure was found when the airport operation changed after the opening of the new terminal at the end of 2014. This effect seems to decline over time but responses remain high when compared to that of the steady state at the same noise exposure level.

In order to obtain sound power level in a single event of aircraft noise, not only successive series of noise levels in each 1/3 octave band under the flight path, but also distance between the measuring site and the aircraft is needed to measure the sound power level is estimated by correcting for the amount of sound attenuation due to spherical spreading and air absorption based on the distance to the noise level obtained at the measuring site. As the technique for measuring this distance, we developed an aircraft-tracking camera system by combining a hemispheric camera and motion-tracking. The effectiveness of this system was examined by means of a case study, and it was confirmed that the distance can be reasonably measured just by leaving this system unattended.

This paper reports a follow-up investigation of the three surveys on step-change noise impact due to the increase of flight number in Hanoi Noi Bai International Airport (HNBIA) after the new terminal building opened in December 2014. The follow-up survey was conducted in November 2017, two years and 11 months after the step-change occurred. About 623 responses were obtained from 13 sites around HNBIA by interview method. Noise exposure levels was obtained by field measurement and using a noise map model. In addition to the main survey items about respondents' living conditions, noise annoyance and activity disturbance, data of residents' health conditions such as Body Mass Index and blood pressure were accessed by self-reported method. The changes in percentages of highly annoyed to noise and insomnia are found to be greatly various among sites. Nonetheless, an exposure-response relationship established in this follow-up study was found to be more parallel to that in the EU position paper than the relationships established in previous surveys but located significantly higher. In other words, though the excess response due to the step-change seems to decline over time but still stay higher than that of the steady state at the same noise exposure level.

© 2016, German Acoustical Society (DEGA). All rights reserved. Recent advances in outdoor acoustic propagation modeling and simulation techniques have enabled wide-area environmental noise assessment as represented by noise mapping. However, among main input information for such an assessment, ground acoustic properties are not available as a geographical dataset, whereas topography is readily obtainable as a digital surface model (DSM). In this paper, a wide-area estimation technique of ground acoustic absorption coefficient using remote sensing is explored. The selected sensor is a CASI-3 airborne hyperspectral imager, which provides high spectral and spatial resolutions in visible and near-infrared optical wavelengths. Hyperspectral images of 34 bands with a ground sampling distance of 1 m was acquired for a region of approximately 1570x3730 m2. Simultaneously, ground acoustic properties were measured using an in-situ technique at 8 locations in the imaged region, each of which has 36 measurement points. A modeling process using single and multiple regression analyses derived a set of equations that estimates the acoustic absorption coefficient from 160 to 3150Hz one-third-octave bands using the optical spectral reflectance tracked down to 3 bands. The acoustic absorption maps obtained by applying the derived model to the entire image provided qualitative validity of the model.

Knowledge of distinct effects of moisture content and air volume on acoustic properties of soil is sought to predict the influence of human activities such as cultivation on acoustic propagation outdoors. This work used an impedance tube with the two-thickness method to investigate such effects. For a constant moisture weight percentage, the magnitude of the characteristic impedance became smaller and the absorption coefficient became higher with increase of the air space ratio. For a constant air space ratio, the absorption coefficient became larger and the magnitude of the propagation constant became smaller with increasing moisture weight percentage. (C) 2015 Acoustical Society of America

With the recent progresses in computer performance and simulation techniques, it is becoming feasible to apply full three-dimensional wave-based numerical simulation techniques to large-scale problems of real-life sound propagation outdoors. In the present paper, a reconstruction technique for real-life urban geometries with full reproduction of the roof shapes and for the ground profiles using digital geographic information is presented. Also, a generation technique for the uniform rectilinear grid used in finite-difference time-domain simulations is presented. The types of geographic dataset used for the reconstruction are a digital surface model and a two-dimensional building outline map. For comparison, another geometry with flat building roofs, which is the type of geometry used in former noise-mapping studies using empirical models, is created. Comparison of the results of finitedifference time-domain acoustic simulations performed over the geometries shows sound pressure level differences above and behind buildings. The maximum level difference of 10 dB in magnitude indicates the necessity of proper reconstruction of the roof shapes in real-life urban acoustic simulations. © 2014 The Acoustical Society of Japan.

The procedure of sound propagation calculation employing the linearized Euler (LE) model has been known to be complex because the procedure requires a chaining of two distinct simulations, namely a fluid dynamics simulation (CFD) in order to solve the background flow field, and a succeeding sound propagation simulation using the LE model over the flow field. The complexity is considered one of the main reasons why the most of the applications of the model remain in investigations assuming highly abstract geometries. In the study, a streamlined workflow is established for LE simulations over a complex urban terrain with its reconstruction utilizing digital geographic models which provide building outline maps and digital surface elevation information. Focus is given to automatic geometry reconstruction and mesh generations of realistic urban terrain. Subsequent processes of CFD and LE simulations are validated through comparisons with published results of wind-tunnel tests and with theoretical solutions. The workflow is deployed to an actual urban terrain of Nagaoka, Japan. The present technique generates a good reconstruction of urban geometry and subsequent split-hexahedral unstructured grid for CFD software and uniform structured mesh for finite-difference LE simulation. The numerical experiments show differences of up to 5 dB between sound pressure levels obtained by the present reconstruction technique and those by a flat-roof geometry. Also, the wind effects are mostly representable in terms of the source-observation point distance in spite of the complex urban configuration. Subtle wind effects of less than 0.5 dB are observed in crosswind condition as well. (c) 2013 Elsevier Ltd. All rights reserved.

The article examines time-domain outdoor acoustic simulation of a real-life area using land cover classification identified by airborne hyperspectral imagery. In order to solve the identification problem, the authors presented a classification technique of using airborne hyperspectral imagery for land cover types in a real-life area. The simulation employs a porous-medium model for the solution of acoustic absorption by the surfaces. A validation of the porous-medium model through comparisons with exact solutions is given. The results are compared with those obtained assuming perfectly reflecting surfaces. The source is a coherent linear Gaussian pulse with a full width at half maximum of 1.25m and an amplitude of 1 Pa placed on a road, assuming a road traffic noise source.

The article presents a possible land cover classification estimation technique specialized for acoustic simulations using high-accuracy hyperspectral imaging data through a case study using a Nagaoka sample. The image was obtained by PASCO Corp. on 5 June 2004 using the Airborne Imaging Spectroradiometer for Application (AISA), which is a hyperspectral sensor with a 1m spatial resolution developed by Spectral Imaging Ltd. The image data comprise 67 bands, covering both the visible and a part of near-infrared wavelengths from 400 nm to 1,000 nm. Spectral band widths are equally spaced by 8-9 nm. The spectrum value at each picture element indicates a normalized spectral reflectance, which is calculated based on the spectral radiance of the ground surface and the sun observed simultaneously. The land cover classification that should be estimated is determined by referring to ASJ RTN-Model 2008 in the first step to discuss classification methods.

雨天時に発生する傘の雨滴衝撃音は,視覚障害者が歩行時に手かがりにしている音の聴取妨害になり交通事故等の原因となっていることから,視覚障害者の雨天時の歩行の安全を確保するために,傘の雨滴衝撃音を低減させることは重要である。本研究は,傘の雨滴衝撃音低減のための基礎的検討として,自作した人工降雨装置による試験方法の有効性とそれを用いて測定した傘の雨滴衝撃音の音響特性について検討した。その結果,点滴針を用いて製作した装置によって自然降雨の雨滴に近い周波数特性を有する衝撃音を発生させることができた。更にその装置を用いて10種類の傘の布の雨滴衝撃音を測定したところ,傘の素材や厚さ,傘の面や水滴の大きさ,張力の違いによる雨滴衝撃音のレベル差が確認でき,傘の雨滴衝撃音を低減させるためには,傘の面を大きくし,雨滴を拡散させて小さくする,布の張力をある程度弱くすることによって雨滴衝撃音を小さくすることができることを示した。

The Acoustical Society of Japan's prediction model for road traffic noise, ASJ RTN- Model 2003, which is generally used for the evaluation of the 'Environmental Quality Standards for Noise in Japan' (EQS), estimates the average noise level as the representative value in the evaluated area. However, because the noise level at each building changes greatly depending on the arrangement of buildings, it is necessary, for the evaluation of EQS, to consider the distribution of noise levels in an evaluated section. From that perspective, a new concept to adopt the most frequent level of insertion loss of road traffic noise as a representative value of the evaluated section is proposed. A simple method to predict the most frequent level of insertion loss is presented that is based on the authors' simulation method of the insertion losses attributable to detached houses. Furthermore, the validity of the proposed equation for evaluating EQS is verified by comparing this method with ASJ RTN-Model 2003, which consists of identical parameters. The result confirms that the proposed prediction equation is appropriate for evaluating EQS.©2010 The Acoustical Society of Japan.

Preservation of silence in the house is important for comfortable living environment. Ventilation openings, which are indispensable to keep indoor air clean, might be a bottleneck in the noise insulation. This study aims at improving noise reduction of the ventilation openings in low-frequency using active noise control(ANC) technique. In our previous study, basic performance of the ANC system for ventilation openings was examined. However, when the living sound is mixed into the ANC system, it is doubtful whether the noise reduction performance of the ANC will be ensured. In this paper, therefore, one tactic distinguishing between outdoor noise and indoor living sound with the difference of sound pressure level acquired by omni-directional and uni-directional microphones of the system is investigated to improve the ANC performance degraded by the living sound.

ASJ RTN-Model 2003, which is generally used for the evaluation of 'the Environmental Quality Standards for Noise' in Japan, estimates the averaged noise levels as the representative value in each estimate section. However, the noise level at each building is greatly changed by the arrangement of buildings. Therefore, it is necessary for the evaluation of the Standards to take the distribution of noise levels in the estimate sections into consideration. From the above viewpoint, we propose a new concept to adopt the most frequent level of insertion loss of road traffic noise as the representative value of each estimate section, and a simple method to predict the most frequent level of insertion loss is presented based on the simulation of the insertion losses caused by detached houses by the authors' method.

In the "Environmental Quality Standards for Noise," the problem of environmental noise in areas facing roads is evaluated by obtaining the numbers and the rates of the buildings at which noise levels exceed the environmental quality standards. In order to estimate noise distribution in the residential area facing roads, it is necessary to grasp the insertion loss caused by the buildings. The authors proposed in the previous study a simple method to predict the insertion loss of road traffic noise caused by detached houses when the road is at the same level with that of the houses. However, there are lots of residential areas where are located around an embanked road. In such residential areas, the noise would be expected to be higher. The purpose of this paper is to derive a new method to predict the insertion loss of road traffic noise caused by detached houses when a road is embanked. A one-twentieth scale model experiment is performed. On the basis of the experimental results, to extend the authors' previous predicting method to be applicable when a road is embanked is examined, and then a simple procedure to compensate the increase of noise level caused by the increase of the height of a road is derived. The results of an additional experiment, comparison with the former studies, and comparison with the measurement verify the validity of the proposed method.

ASJ RTN-Model 2003, which is generally used for the evaluation of the Environmental Quality Standards for Noise in Japan, estimates the averaged noise levels as the representative value in each estimate section. However, the noise level of each building is greatly changed by the arrangement of buildings. Therefore, it is necessary for the evaluation of the Standards to take the distribution of noise levels in the estimate sections into consideration. From the above viewpoint, we propose a new concept to adopt the highest frequency level of insertion loss of road traffic noise as the representative value of each estimate section, and a simple method to predict the highest frequency level of insertion loss is presented based on the simulation of the insertion losses caused by detached houses by the authors' method(F2006).

Design of sound environment of urban shopping arcades is important for promotion of a lively atmosphere and better speech/sound transmission. In this study sound environments in arcades of two cities were surveyed for 1) sound levels and audible distances of sounds from loudspeakers, 2) time of day variation of the sound environment with regard to sound levels and types of audible sounds, and 3) reverberation characteristics. The results were: 1) loudspeakers were widely used and sometimes set toward the street; 2) L_ values in the arcades were around 70dB in the daytime; 3) The reverberation times were around 1.5 seconds at 500Hz when stores opened.

In this study, we obtained an overview of the sound environment in large-scale stores, with the aim of providing better sound conditions in them. We measured the noise levels and the types of audible sound in 139 large-scale stores, selling groceries, electrical appliances, or household equipment. The overall noise level in the stores varied from 52 to 76 dBA. A cluster analysis, which produced groups of stores based on similarities between the patterns of audible time of each sound, revealed that specific sounds, such as information from loudspeakers, were found in the group of stores with a relatively high noise level.

In order to confirm the effect of the shield cloths, the thermal environment, especially air temperature distribution, inside an enclosed arcade with the shield cloths was investigated both in summer 2001 and 2002. At the point without the shield cloths, vertical distribution of air temperature showed a sharp slope in the upper part inside the arcade. However, at the point with the shield cloths, vertical distribution showed a blunt slope. The outside air temperature just on the arcade and under the shield cloths was higher than without the shield cloths.

In order to confirm the effect of the shield cloths, the thermal environment inside an enclosed arcade with the shield cloths was investigated in summer 2001 and 2002. The thermal environment was evaluated by calculating the SET^* and the equivalent air temperature and by voting on thermal comfort. In daytime, air temperature inside the arcade without shield cloths was lower than with shield cloths. From the viewpoint of the penetration ratio of solar radiation, the change 2001 to 2002 wasn't found. The shield cloths on the arcade improved the thermal environment inside the arcade in daytime, but in nighttime some new problems were found.