51 results about "Acoustic pollution" patented technology

The present invention provides an urban road noise prediction system based on the Internet of Things and cloud computing technology. The system realizes real-time prediction of road environmental noise and predicts the impact of the noise level on urban residents through the Internet of Things and cloud computing technology. Population ratio thereby realizes the noise pollution control to road; Described system comprises: real-time data collection platform, data processing platform and road management platform; Described real-time data collection platform is respectively connected with described data processing platform, road management platform data; The purpose of the present invention is to solve the current environmental problem of urban road noise pollution, and reduce or prevent urban residents from being exposed to the noise environment to cause harmful effects by means of detection and prediction.

A method for managing knock in a cylinder of an internal combustion engine, in a system including at least one acoustic sensor and a processor, in order to take into account acoustic pollution resulting from a noise, the method including: forming and digitizing the signals of the acoustic sensor, applying a bandpass filter to obtain a filtered noise, determining an adjustable gain-correction function using a gain-correction curve and, depending on the angular position of the end of injection, the point on the gain-correction curve to be used to convert the filtered noise into a corrected knock score, comparing a corrected knock score thus obtained to a knock decision threshold, to correct the timing advance, the gain-correction curve being defined by a calibration value and four angular points obtained by calculation based on the start and end positions of a knock-observation window and on a known characteristic of the noise.

The invention discloses a method, device, equipment and storage medium for purifying the shaft center track of a rotating machine, which solves the problem of inaccurate purification of the shaft center track caused by signal denoising only in the existing rotor shaft center track purification method; Obtain the vibration signal during the operation of the rotating machinery for harmonic wavelet decomposition to obtain the time-domain characteristics of the vibration signal, and eliminate the influence of noise in the axis track signal; and correct the time-domain characteristics of the vibration signal according to the rotational speed information of the rotating machinery, Extract the time-domain characteristics of the vibration signal corresponding to the rotational speed information of the rotating machinery from the time-domain characteristics of the vibration signal, further filter the noise in the axis track signal, eliminate the interference of complex noise pollution and non-stationary components caused by faults, and accurately The center track of the rotating shaft is purified, and at the same time, the influence of the bandwidth of the frequency band and the constant amplitude of the harmonic wavelet decomposition on the signal reconstruction is reduced.

The invention discloses an adaptive gain control method of a sound reinforcement system. The method comprises the following steps: S1, presetting an initial system gain, and directly picking up a played sound reinforcement source signal in a circuit of the sound reinforcement system; S2, multiplying the sound reinforcement source signal by the initial system gain, and then playing the sound reinforcement source signal through a loudspeaker in the sound reinforcement system; S3, picking up an onsite sound reinforcement mixed signal by setting a microphone on a sound reinforcement site, that is,a signal obtained by performing convolution on a product of the sound reinforcement source signal and the system gain with a sound field pulse, and then adding a noise signal; S4, calculating an estimated onsite signal to noise ratio according to a selected function relationship by using an MSC signal to noise characterization value; and S5, adjusting the gain of the sound reinforcement system according to the estimated onsite signal to noise ratio. By adoption of the adaptive gain control method of the sound reinforcement system provided by the invention, the gain setting of the sound reinforcement system is more accurate, the sound reinforcement volume is suitable, and the adjusted sound signal on the sound reinforcement site is obviously clearer than the onsite sound signal performed with no adaptive adjustment without increasing sound pollution.

The invention discloses a multi-net type foldable underwater piling noise reduction device and its implementation method, including a fixing device, a power and data feedback device, a telescopic lifting net cage and a control device. The power and data feedback device can be detachably set on the pile foundation on the lower side of the fixing device, and the power and data feedback device can be detachably connected with the telescopic lifting net cage. Each layer of the multi-layer net curtain is equipped with a vertical lifting rod vertically. The power and data feedback device includes an infrared receiver, a battery motor and a Bluetooth signal device. The battery motor drives the horizontal telescopic rod or the vertical telescopic rod according to the signal received from the control device. The Bluetooth signal device collects the noise from the acoustic sensor on the horizontal telescopic rod and feeds it back to the control device. The invention can be used for underwater noise reduction of piling, in order to reduce noise pollution of marine environment.

The present invention proposes an intelligent evaluation method for ECG signal noise pollution degree and category, including the following steps: S1, ECG signal preprocessing; S2, ECG signal component characteristic mathematical statistical calculation; S3, ECG signal noise pollution degree judgment; S4, low frequency baseline Judgment of drift noise pollution degree; S5, judgment of high-frequency component noise pollution category and pollution degree; S6, comprehensive evaluation of ECG signal overall noise pollution degree and category. The evaluation method of the present invention integrates the M-CEEMD signal decomposition and the SVC network cluster to accurately complete the evaluation of the noise pollution degree of the ECG signal and the automatic classification of pollution types. Realize the screening of available ECG signals, provide a basis for the selection of targeted filtering methods, improve the filtering effect while retaining the original ECG data information to the greatest extent, reduce the false positive rate of ECG intelligent diagnosis, and improve the diagnostic accuracy rate , has the characteristics of strong clinical generalization and high classification accuracy.