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With the continuous advancement of deep space exploration missions, the solar system boundary exploration mission is established as one of the China's most important deep space scientific exploration missions. The mission of the solar system boundary exploration has many challenges such as ultra-remote detection distance, ultra-long operation time, and ultra-long communication delay. Therefore, the problem of high-precision autonomous navigation needs to be solved urgently. This paper designs an autonomous intelligent navigation method based on X-ray pulsars in the cruise phase, which estimate the motion state of the probe in real time. The proposed navigation method employs the Q-learning Extended Kalman filter (QLEKF) to improve navigation accuracy during long periods of self-determining running. The QLEKF selects automatically the error covariance matrix parameter of the process noise and the measurement noise by the reward mechanism of reinforcement learning. Compared to the traditional EKF and AEKF, the QLEKF improves the estimation accuracy of position and velocity. Finally, the simulation result demonstrates the effectiveness and the superiority of the intelligent navigation algorithm based on QLEKF, which can satisfy the high-precision navigation requirements in the cruise phase of the solar system boundary exploration. [ABSTRACT FROM AUTHOR]

An assessment of workers at the mechanized mining face of coal mines was conducted in China. The survey on the current status of subject exposure to noise of coal miners was administered by occupational health investigation and detailed record of work days. The noise dosimeter measurements of 211 workers were obtained, including coal cutting, supporting, transportation, crushing, and auxiliary (such as air pressure, pump, and maintenance). A total of 56.4% of the LEX,8h exceeded 85 dB(A), and the average 8-hour equivalent sound level of the workers at the mechanized mining face of these coal mines was 91.2 dB(A). Within the noise frequency from 500 to 6000 Hz, there was a "V" shift in the displacement value of hearing threshold. At the noise frequency of 4000 Hz, the hearing loss N50 (dB) of workers reached the maximum. The longer the exposure time, the higher risk both in high-frequency hearing loss and noise-induced deafness. The risk of high-frequency hearing loss reached the high-risk level at 25 years of work, while the risk of noise deafness reached the high-risk level after 30 years of work. In addition, the Pearson correlation coefficient between the noise exposure time and the risk of noise-induced hearing loss was high and positively correlated. The results show that the production noise hazards at the mechanized mining face of coal mine are relatively large. High levels of hazardous noise exposure are typical in coal mines. The noise exposure data can help to develop more feasible noise controls for the employer. [ABSTRACT FROM AUTHOR]

Hong Kong Cantonese (HKC) and Guangzhou Cantonese (GZC) are two major accents of Cantonese spoken in two geographically non-contiguous cities in Southern China. Previous studies were unable to identify the phonetic features that discern the two accents since they share the same phonological system. This study attempted to solve the puzzle by investigating the voice quality differences between the two accents through acoustic analysis on the speech output of 191 talkers in three age groups ranging from 18 to 65 years old. Among the various spectral and noise measurements of voice quality, we found that Cepstral Peak Prominence (CPP) was the best acoustic measure to discern the two accents. Based on the CPP measure, GZC had overall increased noise than HKC. Covariation of voice quality and tones was studied. The greatest CPP differences between the two accents were found in the two extreme tones: the high-level and the extra-low-level tones. Furthermore, creaky voice was found mainly tied to the extra-low-level tone in both accents. However, HKC exhibited higher frequency of creaky voice than GZC. The creaky voice in GZC was characterized by increased noise and increased tension, compared to those of HKC. Finally, age was found to be a mediating factor in the voice quality of the two accents. Adopting the Apparent Time Framework, voice quality in the two cities has undergone changes over time. The voice quality of the young generations of the two accents have become merged among the three low tones. Furthermore, the prevalence of creaky voice was increasing across age groups in both accents, and it increased at a faster rate in HKC than GZC. [ABSTRACT FROM AUTHOR]

In the Gobi desert region, the predominant frequency of the horizontal-to-vertical spectral ratio (HVSR) curve of seismic noise ( f H / V ) is typically above 3 Hz. However, most of the existing formulas for estimating cover thickness (H) based on f H / V are only applicable for f H / V values below 5 Hz. Therefore, new formulas that can accurately calculate H in this region are crucially needed. To this end, a case study was conducted where noise measurements were carried out in the Gobi region in China, as well as in the east and northeast regions of China. The HVSR curves and f H / V were calculated, and a formula that correlates f H / V with H was derived. In addition, formulas that correlate with Vs20 (average shear-wave velocities to depth 20 m) and Vs30 (average shear-wave velocities to depth 30 m) f H / V were fitted. The relationship between the site fundamental period ( T s ) and T H / V (1 / f H / V ) was also investigated. Finally, by using all of the noise measurements and applying the derived relationships, a method for rapidly measuring the site type was proposed. The results showed that the equation for calculating H in this paper is highly reliable, with relative errors less than 30% compared to other researchers. The correlation between f H / V and Vs30 was higher than that between f H / V and Vs20. The accuracy rate of the proposed method for fast identification of ground types was greater than 80%. [ABSTRACT FROM AUTHOR]

High-resolution land cover mapping over large areas is a challenging task due to the lack of high-quality labels. A potential solution is to leverage the existing knowledge contained in the freely available lower-resolution land cover products. However, the relatively low resolution and low accuracy of the products lead to numerous inaccurate labels, which harms the performance of the neural network. This article addresses the challenge by jointly optimizing the network parameters and correcting the noisy labels with a novel online noise correction approach and a synergistic noise correction loss. By incorporating the information entropy as a measurement to determine the probable correct labels, the proposed noise correction approach learns to make effective correction of the noisy labels during training and eventually boosts the performance with a training set containing less noisy labels. Experimental results show that the proposed method can effectively correct the noisy labels and reduce their negative impact on network training. By employing the proposed method, we produce a refined high-resolution (3-m) land cover map from a lower-resolution (10-m) product in China and improve the accuracy from 74.96% (10-m) to 81.32% (3-m). Such an approach that can effectively learn from noisy data sets leads to many potential opportunities for using and magnifying existing knowledge and results. [ABSTRACT FROM AUTHOR]

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Background: The purpose of this study was twofold: (1) to measure the personal attenuation ratings (PARs) in Chinese workers wearing hearing protection devices (HPDs), to evaluate the effectiveness of the single number rating (SNR), the noise reduction rating (NRR), and the associated derated values of earplugs; and (2) to evaluate the effectiveness of one‐on‐one training along with earplug fit testing on PAR improvement. Methods: Noise exposure measurements, one‐on‐one training, and fit tests to measure earplug attenuation were conducted at nine manufacturing facilities located in eastern China from 2016 to 2017. 503 workers participated in the study. Ninety‐three percent were male. 199 workers were provided one‐on‐one training. Results: Before training, 14% and 15% of the workers achieved the attenuation predicted by the manufacturer's SNR and NRR, 56% and 65% exceeded the derated SNR and NRR, respectively. Following one‐on‐one training, mean PAR improved significantly by 15 dB (p < 0.01); 26% of the workers achieved SNR and NRR, 79% and 91% met the associated derated values, respectively. Conclusions: Labeled noise attenuation ratings and their derated values overestimated the actual level of attenuation among workers wearing HPDs. One‐on‐one training along with earplug fit testing contributed to improved PARs. [ABSTRACT FROM AUTHOR]

As urbanization grows at an unexpectedly rapid pace around the world, the underground space is gradually regarded as a largely undeveloped natural resource. Passive surface wave methods based on short-time traffic-induced noise measurements have been shown to be powerful tools for underground imaging and monitoring in urban areas. The common surface-wave investigations mainly focus on the use of Rayleigh waves in vertical components. We have developed an application of using three-component traffic-induced surface waves to investigate near-surface structures in Hangzhou City, Eastern China. With the deployment of two dense linear arrays along the orthogonal roads, we analyze the temporal and spectral characteristics of the three-component traffic noise. The retrieval of Rayleigh and Love waves using the horizontal components could be biased due to the uneven noise source distribution and errors in the orientation of the horizontal receivers. We use the match-field processing technique to obtain the direction of noise source distribution, and apply polarization analysis to evaluate the misorientation of the horizontal components. Subsequently, high-quality Rayleigh and Love waves are retrieved based on seismic interferometry within 1 h noise recordings. We invert the multicomponent surface waves to determine near-surface shear (S)-wave velocity structures. The joint analysis of Rayleigh and Love waves improves the reliability and stability of the result. Comparisons among the results from the individual inversion of Rayleigh waves, the joint inversion of Rayleigh and Love waves, and the logging data demonstrate that the jointly inverted S-wave velocity profiles provide better correspondence with the logging results, which confirms that the combined use of Rayleigh and Love waves from multicomponent traffic noise can be a more powerful technique for near-surface characterization in urban areas. • Developed an application using three-component traffic-induced surface waves to investigate urban near-surface structures. • We analyze the noise sources direction by MFP method and the misorientation of horizontal component by polarization analysis. • Combined use of Rayleigh and Love waves from traffic noise offers an efficient method for urban subsurface characterization. [ABSTRACT FROM AUTHOR]

Over-track buildings have been increasingly favored in the construction of metro depots and freight depots in China in the last decade due to advantages of intensive utilization of land resources and high-profits. However, due to the relatively heavy transportation mass and high-operating frequency of bridge cranes, over-track buildings are often complained by occupants for annoying noise and vibrations. So far this issue is rarely concerned and the characteristics of noise and vibrations under bridge crane loading remain unclear. In this study, field measurements of two full-scale over-track buildings, including a seven-story building over a metro depot and a three-story building over a freight depot, were conducted. Vibration characteristics of both the structure and the bridge crane were obtained. The transmission of vibrations from bridge crane system to the over-track building was obtained by transfer function (TF) of vibration from the column bracket towards the outdoor platform or building floors. The structure-borne noise inside the building was also captured and evaluated. The effect of bridge crane operational parameters (loading capacity and running velocity) and structural dynamic properties (non-structural components) on system responses was further discussed. Results show that the bridge crane–induced vibrations are comparable to the levels of train-induced vibrations. Besides, both buildings tested in this study suffer from unacceptable structure-borne noise, although the building vibration is acceptable. We recommend to carefully examining design of new over-track buildings to avoid annoying indoor noise and improve the living or working environment of occupants. It is demonstrated that vibrations of over-track buildings are more sensitive to running velocity than load capacity of bridge crane. It could be expected that the future increase of velocity will worsen the noise and vibration environment of over-track buildings. Furthermore, it is seen that non-structural components would remarkably affect dynamic responses of the building. [ABSTRACT FROM AUTHOR]

In this paper, a novel descriptor estimator-based incipient fault estimation scheme is designed for Lipschitz nonlinear descriptor systems with process disturbances and measurement output noises. By using the proposed estimator, incipient sensor faults, abrupt actuator faults, and measurement noises can be estimated asymptotically. Application results conducted on a three-phase inverter system of China railway high-speed trains are given to illustrate the effectiveness of the developed approach. The main contributions are summarized in two aspects: 1) the unified framework designed for actuator and sensor fault reconstruction/estimation problem is capable of dealing with actuator and sensor faults at the same time and 2) a linear matrix inequality optimization method is formulated to achieve optimal performance of signal estimation. [ABSTRACT FROM AUTHOR]

Context: Noise sensitivity may mediate or moderate the influences of noise exposure on health, and it needs to be reliably evaluated. The 21-item Weinstein's noise sensitivity scale (WNSS) has been the most popular scale for assessing noise sensitivity, but it is not yet available in traditional Chinese.Aims: This study aimed to conduct linguistic and psychometric performance of WNSS in Hong Kong (HK) Chinese.Settings and Design: A population-based telephone survey with 1-week follow-up.Materials and Methods: The HK Chinese WNSS was obtained after forward-backward translation from the original English version and cognitive debriefing in five Chinese adults. Its measurement properties were assessed in 569 Chinese adults aged 18 years or above.Statistical Analysis Used: The sample was randomly split into two halves. The first half was used to explore a scale structure of the WNSS by exploratory factor analysis (EFA) with the number of factors determined by the optimal comparison data technique and tested for being artifactual. The second half was used for confirmatory factor analysis. Convergent validity and test-retest validity were also assessed.Results: EFA identified two unipolar factors and removed three items poorly associated with the factors. The factors were likely artifactual and a unidimensional structure was assessed in CFA, which showed a satisfactory fit (root mean square error of approximation = 0.055; comparative fit index = 0.904; standardized root mean square residual = 0.061). The HK Chinese WNSS had good internal consistency (Cronbach's α = 0.83) and test-retest reliability (intraclass correlation coefficient = 0.87). Furthermore, it confirmed the expected association with extraversion (r = -0.14, P < 0.001) and neuroticism (r = 0.28, P < 0.001).Conclusion: The 18-item HK Chinese WNSS was reliable and valid for assessing noise sensitivity in the Chinese population. [ABSTRACT FROM AUTHOR]

In this study, the impact of noise and jump on the forecasting ability of volatility models with high-frequency data is investigated. A signed jump variation is added as an additional explanatory variable in the volatility equation according to the sign of return. These forecasting performances of models with jumps are compared with those without jumps. Being applied to the Chinese stock market, we find that the jump variation has a significant in-sample predictive power to volatility and the predictive power of the negative one is greater than the positive one. Furthermore, out-of-sample evidence based on the fresh model confidence set (MCS) test indicates that the incorporation of singed jumps in volatility models can significantly improve their forecasting ability. In particular, among the realized variance (RV)-based volatility models and generalized autoregressive conditional heteroscedasticity (GARCH) class models, the heterogeneous autoregressive model of realized volatility (HAR-RV) model with the jump test and a decomposed signed jump variation have better out-of-sample forecasting performance. Finally, the use of the decomposed signed jump variations in predictive regressions can improve the economic value of realized volatility forecasts. [ABSTRACT FROM AUTHOR]

This paper aimed at proposing an inland waterway traffic noise prediction model for environmental assessment in China. The study was the first to predict inland waterway traffic noise levels considering water surface condition and absorption influence in China. The analysis results indicated that the inland waterway traffic noise exposure levels can be influenced by water surface. The model was developed based on the Germany Schall 03 model by adding the water surface condition and absorption correction terms to the governing equations. Results showed that the predicted noise levels by the developed model correlated well with the measurements. In addition, the developed model had higher precision compared with the existing models such as the Schall 03 model, the modified US Federal Highway Administration (FHWA) model and the modified Germany Richtlinien für den Lärmschutz an Straßen (RLS 90) model. The proposed model can be utilized to assess inland waterway traffic noise exposure in China. [ABSTRACT FROM AUTHOR]

Based on the local environmental standards, vessels types and traffic conditions, an inland waterway traffic noise prediction model was developed for use in China. This model was modified from the US FHWA model by adding the ground absorption and water surface attenuation correction terms to the governing equations. The parameters that were input into the equations, including traffic flow, vessel speed, distance from the center of the inland waterway to the receiver, position and height of the barriers and buildings, location of the receiver, type of ground, percentage of soft ground cover within the segment, and water surface conditions were re-defined. The model was validated by comparing the measured noise levels obtained at 33 sampling sites from Shugang Channel, Yanhe Channel and Danjinlicaohe Channel in China with the predicted values. The deviation between the predicted and measured noise levels within the range of ±1.5dB(A) was 81.8%. The mean difference between the predicted and measured noise levels was 0.15±1.75dB(A). However, the noise levels predicted developed model are generally higher than the measured levels. Overall, the comparison has proved that the developed method is of a high precision, and that it can be applied to estimate the traffic noise exposure level on inland waterway in China. [ABSTRACT FROM AUTHOR]

In Yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis, the effects of fatiguing noise on hearing thresholds at frequencies of 32, 45, 64, and 128 kHz were investigated. The noise parameters were: 0.5-oct bandwidth, -1 to +0.5 oct relative to the test frequency, 150 dB re 1 μPa (140-160 dB re 1 μPa in one measurement series), with 1-30 min exposure time. Thresholds were evaluated using the evoked-potential technique allowing the tracing of threshold variations with a temporal resolution better than 1 min. The most effective fatiguing noise was centered at 0.5 octave below the test frequency. The temporary threshold shift (TTS) depended on the frequencies of the fatiguing noise and test signal: The lower the frequencies, the bigger the noise effect. The time-to-level trade of the noise effect was incomplete: the change of noise level by 20 dB resulted in a change of TTS level by nearly 20 dB, whereas the tenfold change of noise duration resulted in a TTS increase by 3.8-5.8 dB. [ABSTRACT FROM AUTHOR]

The article presents a research study concerning the 1/f-noise measurement and its significance in climate and weather observations in Yangtze River, China. Researchers cited the usefulness of such measurement in determining the variations and spectrum of humidity, precipitation, temperature, and wind speed. The river's high volatility and its intra-annual 1/f spectrum is also determined.

Traffic noise is one of the major global concerns regarding impacts on the quality of the human environment. A number of predicted noise analysis methodologies have been developed to evaluate these impacts, but few studies have been conducted on the differences in noise analysis methods between developing countries and developed countries. This paper examines the differences in traffic noise policies and analysis methods between Guangzhou City and New York City, in an effort to represent a general case for traffic noise analysis between China and the USA. In Guangzhou City, Technical Guidelines for Noise Impact Assessment (HJ/T2.4-1995), issued by Ministry of Environmental Protection of the People's Republic of China, outlines appropriate methods for environmental noise assessment. In New York City, the City Environmental Quality Review Technical Manual outlines appropriate methods for environmental noise assessment. This paper briefly demonstrates for each the relevant noise policy, standards, predicted models, and methodologies for traffic noise analyses. This paper also presents detailed traffic noise analysis procedures for two Environmental Impact Statement studies. Finally, experimental findings are summarized to explore differences in traffic noise assessment between China and the USA. The findings in this study may be beneficial to the Global Noise Policy for the implementation of effective traffic noise control technology. [ABSTRACT FROM AUTHOR]

In Hong Kong, approximately one million people are affected by severe road traffic noise. It is crucial to estimate the vertical distribution of traffic noise levels at different levels in high-rise buildings during the planning and design stages for new residential buildings. The Calculation of Road Traffic Noise (CRTN) has been adopted in Hong Kong to estimate traffic noise from the road. However, there have been criticisms of the CRTN model's accuracy and suitability for predicting road traffic noise in Hong Kong. This study examines and evaluates the accuracy of the CRTN method in predicting the vertical distribution of traffic noise level LA10 at different floor levels of a 20-storey residential building in Hong Kong. Also, measurements have been conducted of the traffic noise levels at each floor level of the building. Both the predicted and measured LA10 show a similar trend: the higher the floor level, the lower the traffic noise levels. However, the predicted LA10 at the building façade has a tendency of overestimation, especially at the higher floor levels, with a mean difference of +2.0 dBA between the predicted and measured results. A correlation coefficient (R2) of 0.9331 between the predicted and the measured LA10 indicates that the predicted levels correlate closely with the measured levels. The CRTN is therefore a useful tool in predicting traffic noise levels at different floor levels during the building planning stage. Practical application: This study provides an evaluation of the accuracy of the CRTN method in predicting the vertical distribution of traffic noise level at different floor levels of a residential building. It suggests that the CRTN is a useful tool in predicting traffic noise levels at different floor levels during the building planning stage. [ABSTRACT FROM AUTHOR]

• The influence of rail corrugation on environments was investigated by field measurement. • Subway induced high-frequency noise and vibration of surrounding buildings was proved not negligible. • Indoor noise and vibrations were greatly alleviated after rail grinding. • The influence of high-frequency excitations should be concerned in environmental assessment standards. Environmental noise and vibration induced by subways can cause human annoyance near the lines. Rail corrugation, one of the most serious defects in subway lines, can cause high-frequency vibration. Previous research findings showed that the influence of high-frequency vibration on surrounding environment is insignificant. However, in a case reported from China, residents living nearby a subway line felt the effects of high-frequency noise and vibration even though the impact did not exceed the Chinese standard JGJ/T 170-2009. A field measurement was presented to study the high-frequency influence of rail corrugation. Noise, vibration and rail corrugation tests were carried out. A high-frequency peak above 200 Hz was captured. It was identified to be related to rail corrugation by comparison tests. The case indicates that the high-frequency influence should not be neglected. The risk of neglecting high-frequency noise and vibration of subways should be considered during the revision of environmental assessment standards. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess employees' exposure to lead and noise, and to recommend control strategies for reducing these exposures at eight registered electronics recycling facilities in Eastern China. Jiangsu Provincial Center for Disease Control and Prevention (JSCDC) performed a walkthrough and review of health and safety programs during a first visit and conducted full-shift personal and area air monitoring for lead, as well as personal noise exposure measurements on a second visit. Monitoring was performed over two work shifts for a total of 168 employees. Results indicated that employees working at glass breaking and cathode ray tubes dismantling were overexposed both to noise and lead. Airborne lead concentration ranged from 0.1 to 148 μg/m3; and 4 of the 101 samples were above the Chinese permissible exposure limit of 50 μg/m3. Overexposures to lead involved cathode ray tubes dismantling and glass breaking. Employees working at plastics shredding and glass breaking areas were overexposed to noise. Full-shift time-weighted average noise levels ranged from 64 to 107 dBA; and 85 of the 123 samples were above the Chinese permissible exposure limit of 85 dBA. Control measures to reduce exposure to lead and noise, including improvements in their lead protection and hearing conservation programs, at these electronics recycling facilities were recommended. [ABSTRACT FROM AUTHOR]