Acoustic Spectral Analysis Research Articles

Acoustic Spectral Analysis for Emergency Vehicle Detection: Symbolic and CNN Approaches

During emergencies, ambulances on city streets face delays due to traffic obstacles. This paper addresses two efficient emergency vehicle detection (EVD) methods for restricted hardware implementation considering noisy conditions: a symbolic processing-based algorithm and a convolutional neural network (CNN) model, both of which utilize Mel spectrogram representations of Hi-Lo siren audio records. The symbolic method employs regular expressions and acceptance criteria to process text-pattern features extracted from spectrograms, offering a self-explanatory, easily tunable, and resource-efficient solution suitable for lowcost hardware platforms. On the other hand, the CNN model directly processes spectrogram representations, leveraging spatial correlation for classification with a streamlined architecture consisting of very few layers. The experimental results demonstrate that both approaches achieve high accuracy (97-98%) in classifying Hi-Lo sirens, with the CNN model exhibiting slightly better performance. Challenges such as signal noise and harmonics are addressed through iterative algorithms and signal reconstruction considerations. Future directions include identifying additional siren effects and conducting performance measurements on constrained hardware devices. Overall, this study presents viable EVD solutions suitable for real-time implementation and underscores the importance of adaptable and explainable AI methods in enhancing road safety.

Identification of soils, grounds and lands strata using the acoustic spectral analysis

One of the important tasks of computer technology for the dispersed systems’ analysis of soils, grounds and lands strata is the determination of their qualitative (elemental) composition and quantitative ratio. Due to the complexity and cumbersomeness of traditional methods of chemical analysis, to solve such problems, modern technologies for the express analysis of the disperse systems under study, based on indirect measurements and computer calculation methods, are required.The developed computer technology for determining the elemental composition of the studied disperse systems is based on the acoustic emission signal (AE) Fourier spectrum analysis emitted by these systems as a result of vibro-acoustic exposure. The (AE) signal of the studied systems is recorded in the form of phonograms, which are converted to digital form and processed using the fast Fourier transform. The result of this transformation is the total (AE) signal spectrum, which is a superposition of the spectra belonging to the elements of the studied system.To determine the qualitative (elemental) composition of the studied system, signs are taken that uniquely identify the elements of the system. In the study of dispersed systems, the eigenfrequencies of the particle particles are taken as such signs. These frequencies make it possible to distinguish frequency sub-spectra corresponding to one or another element in the general signal spectrum (AE). Based on the sub-spectra analysis, the presence degree of these elements is considered. Thus, the task of determining the elemental composition is reduced to the selection and analysis in the (AE) total spectrum of the studied sub-spectra system corresponding to each element.

Acoustic Signatures of Left Ventricular Assist Device Thrombosis.

Left ventricular assist devices (LVADs) are life-saving, surgically implanted mechanical heart pumps used to treat patients with advanced heart failure (HF). While life-saving, LVAD support is associated with a high incidence of complications, making early recognition and management of LVAD complications a critical need. Blood clot formation within the LVAD, known as LVAD thrombosis, is a catastrophic complication of LVAD therapy that often requires LVAD exchange due to delayed diagnosis and treatment. Using digital stethoscopes, we identified differences in acoustic spectra from two patients presenting with LVAD thrombosis compared with normally functioning LVAD pumps within the same patient. Importantly, these acoustic changes were present even in the absence of typical signs of HF that are often present in LVAD thrombosis patients. Our work suggests that acoustic spectral analysis of digital stethoscope signals could be used for early detection and mitigation of LVAD complications.

Research Nature of Damage Parts Machines for the Purpose of Optimization Technology Recovery

The results of metallographic studies and microhardness damaged sections detail “axis” the excavator P & H 2800 XPC, subjected to accelerated deterioration the local. Lots of studies to be removed during the repairs identified by magnetic noise control and acoustic spectral analysis. A repair technology.

레일표면 측정장치의 설계변수가 음향조도 스펙트럼 분석에 미치는 영향

레일표면 측정장치의 설계변수가 음향조도 스펙트럼 분석에 미치는 영향

Temperature-controlled acoustic surface waves

Conventional approaches to the control of acoustic waves propagating along boundaries between fluids and hard grooved surfaces are limited to the manipulation of surface geometry. Here we demonstrate for the first time, through theoretical analysis, numerical simulation as well as experimentally, that the velocity of acoustic surface waves, and consequently the direction of their propagation as well as the shape of their wave fronts, can be controlled by varying the temperature distribution over the surface. This significantly increases the versatility of applications such as sound trapping, acoustic spectral analysis and acoustic focusing, by providing a simple mechanism for modifying their behavior without any change in the geometry of the system. We further discuss that the dependence between the behavior of acoustic surface waves and the temperature of the fluid can be exploited conversely as well, which opens a way for potential application in the domain of temperature sensing.

Optimization design of the valve spring for abnormal noise control in a single-cylinder gasoline engine

To address the abnormal noise problem of single-cylinder gasoline engines in the idle condition, acoustic spectral and intensity analysis was carried out. Then the noises were identified as valve impact noises caused by the anomalous dynamic performance of the engine valve mechanism. To improve further the dynamic performance of the mechanism by optimization of the valve spring, a multi-body dynamic model of the valve mechanism was developed on the basis of the key performance and the structure parameters of the valve spring. By using the optimization strategy, the oscillation amplitude of the valve spring and the valve impact force can be reduced by about 62.5% and 27% respectively. Finally, optimized sample pieces were produced for acoustic verification tests. The obtained results showed that the engine’s overall working noise was reduced by about 2.0 dB(A), and the sound quality of the engine was determined using both objective measurements and subjective evaluation of the noise, vibration and harshness performance. It can be concluded that the valve impact noise can be reduced by optimization of the valve springs.

Acoustic spectral analysis for determining pump thrombosis in rotary blood pumps.

Implantation of rotary blood pumps is an established treatment for end-stage heart failure. Anticoagulation is routinely used for reducing pump thrombosis, but this severe complication still occurs in 5-8% of patients. In 105 patients, the sound produced by the left ventricular assist device HeartWare HVAD was prospectively and sequentially recorded. The acoustic spectra calculated by runtime fast Fourier transformation were investigated. Results were compared with respect to patients without thrombotic complications (97 patients) and those with signs of pump thrombosis (8 patients). All eight pumps exchanged were opened and investigated. Thrombus formation was confirmed in all eight exchanged pumps. The existence of a sound peak with the threefold frequency of the pump speed correlated with the presence of thrombi inside the pump (p < 0.001). An increase in the sound amplitude of the rotary frequency of approximately 75% compared to previous measurements also denotes pump thrombosis. Analysis of the acoustic spectrum of the HVAD pump can be used as a reliable method to detect pump thrombosis. The appearance of third harmonics indicates the presence of thrombotic particles independently of previous baseline measurements. The goal of this study is to define and validate such a method.

Acoustic spectral analysis: a new method for thrombus detection in the HeartWare HVAD pump

Objectives: Pump thrombosis is a severe and life-threatening complication in patients supported by rotary blood pumps. Early detection and treatment is crucial to prevent further damage caused by hemolysis or low pump output. Analysis of the sound generated by the running HVAD pump reveals thrombus formation independently of other clinical or technical signs.

Acoustic spectral analysis for determining pump thrombosis in the HeartWare HVAD pump

Objectives: Implantation of a rotary blood pump (RBP) is an established treatment for end-stage heart failure. Patients supported by a RBP need anticoagulation medication to prevent thrombosis. Pump thrombosis is a severe complication occurring in up to 5% of patients and its early and exact detection is crucial for optimal treatment. Analysis of the acoustic spectrum emitted by the HeartWare HVAD indicates the presence of thrombi in the pump.

Lateral Phase Mucosal Wave Asymmetries in the Clinical Voice Laboratory

Summary: Anecdotally, in some persons it has been observed by the Senior Author (K.K.) that asymmetries of the mucosal wave exist when examined videostroboscopically. In the vast majority of these people, no pathology is ever discovered. Mucosal wave asymmetries could cause concern for the otolaryngologist, who may consider them to be a forewarning of subclinical pathology and subject the patient to unnecessary, expensive, and anxiety-provoking investigations or interventions. The purpose of this study was to establish the prevalence of mucosal wave asymmetries in an asymptomatic population lacking laryngeal pathology. Acoustic spectral analysis is also utilized to determine if the presence of subharmonics might be associated. A hospital-based, cross-sectional study design was used. The subjects had no known vocal or medical pathologies, and were nonsmoking. The study group was composed of 30 males aged 35–50 years and 30 women between 22–55 years. Each of the males underwent acoustic spectral analysis; and all subjects completed a medical questionnaire, subjective talkativeness rating, and videostroboscopic laryngeal examination. 10.5% of the subjects (exact 95% CI = 4.0–21.5%) exhibited mucosal wave variations at stroboscopy, characterized as periodic lateral phase asymmetries found consistently in both the modal and upper registers. There was no association with the chosen acoustic spectral parameters, talkativeness scales, or questionnaire-based variables. Mucosal wave asymmetries may be a variance of normal, and are likely to be far more common in the general population than previously believed. The prevalence detected here is expected to be important in the clinical laryngology practice, where these asymmetries may be frequently encountered and influencing management decisions. There has been little normative data published for variations of the mucosal wave specifically for epidemiological purposes. Clinically, in the absence of such data, otolaryngologists may over interpret videostroboscopic findings, leading to unnecessary investigations or interventions.

Improved Interpretation of the Acoustic Response Spectrum to Identify Types of Component Deviations

The evaluation of components by acoustic spectral analysis is a widely applied tool in nondestructive testing. This method requires reasonable effort, is fast, and can be easily integrated into the production process. Specimens whose acoustic spectra at a given excitation deviate beyond certain margins are isolated and rejected. An essential disadvantage of this method, however, is that there is no distinction between acceptable deviations from the design structure (e.g., tolerable thickness variations) and critical defects (e.g., flaws). Thus a method has been developed that in many cases allows us to identify the type of imperfection and to distinguish between tolerable deviations from the design shape and critical defects such as cracks. The basic idea is to correlate the shift of the acoustic spectrum to typical changes of the geometry or the material and to correlate the shift of the spectrum to the shift in geometry. The method has been improved on several academic and industrial applications and proven to be powerful. Nevertheless, there are some limitations to its applicability, and a lot of experience is required for successful use in the manufacturing process.

Improved Interpretation of the Acoustic Response Spectrum to Identify Types of Component Deviations

The evaluation of components by acoustic spectral analysis is a widely applied tool in nondestructive testing. This method requires reasonable effort, is fast, and can be easily integrated into the production process. Specimens whose acoustic spectra at a given excitation deviate beyond certain margins are isolated and rejected. An essential disadvantage of this method, however, is that there is no distinction between acceptable deviations from the design structure (e.g., tolerable thickness variations) and critical defects (e.g., flaws). Thus a method has been developed that in many cases allows us to identify the type of imperfection and to distinguish between tolerable deviations from the design shape and critical defects such as cracks. The basic idea is to correlate the shift of the acoustic spectrum to typical changes of the geometry or the material and to correlate the shift of the spectrum to the shift in geometry. The method has been improved on several academic and industrial applications and proven to be powerful. Nevertheless, there are some limitations to its applicability, and a lot of experience is required for successful use in the manufacturing process.

Mucosal wave asymmetries in the clinical voice laboratory.

Anecdotally, it has been observed that in some healthy middle-aged men, who have neither vocal complaints nor known vocal pathology, asymmetries of the mucosal wave exist when examined videostroboscopically. This may cause concern on the part of the otolaryngologist, who might consider mucosal wave asymmetries to be a forewarning of subclinical pathology and subject the patient to unnecessary, expensive, and anxiety-provoking investigations or interventions. The purpose of this study is to establish the presence of mucosal wave asymmetries in a healthy, asymptomatic subpopulation. Acoustic spectral analysis is also used to determine if the presence of subharmonics might be associated. A prospective, cohort study design was used. The population was randomly selected, healthy, asymptomatic, nonsmoking men aged 35 to 50 years. Each subject completed acoustic spectral analysis and a medical questionnaire, followed by videostroboscopic laryngeal examination. Thirty-seven percent of the subjects exhibited mucosal wave variations at stroboscopy, characterized as periodic lateral phase asymmetries. There was no association with the acoustic spectral parameters chosen. Mucosal wave asymmetries may be a variance of normal. The 37% found here is expected to be very significant. Mucosal wave asymmetries are likely to be far more common in the general population than previously believed. There have been few normative data published for variations of the mucosal wave specifically for epidemiologic purposes. These results establish a starting point and justification for the normative population studies under way at our institution. Clinically, in the absence of such data, otolaryngologists may overinterpret videostroboscopic findings, leading to unnecessary investigations or interventions.

Acoustic and airflow spectral analysis of voice tremor.

Acoustic spectral analysis has been used to describe voice tremor with some success, but no feature distinguishing pathological from normal tremor has been clearly identified. To assist in monitoring voice tremor associated with neurological diseases, objective and quantifiable measures that can distinguish between normal and pathological tremor are desired. This study explored the plausibility of using airflow and acoustic signals to quantify the frequency and amplitude of voice tremor and potentially to distinguish pathological from normal tremor. Subjects were 10 individuals with pathological tremor, most of them individuals with Parkinson's disease, and 10 gender and age-matched individuals with no voice disorder. Simultaneous acoustic and airflow signals were recorded during sustained vowel phonation. The acoustic intensity contours and the airflow signals were submitted to spectral analysis. A peak prominence ratio, defined as the ratio of the spectral peak energy to the overall signal energy, was calculated for each spectral peak below 30 Hz. For each subject, the 6 spectral peaks with the highest peak prominence ratios were selected. Frequency values of the 6 selected acoustic or airflow spectral peaks failed to distinguish tremor group from control group. Peak prominence ratios of the 6 selected acoustic spectral peaks were significantly higher for tremor group than for control group. Although spectral analysis of airflow signals was not useful in differentiating tremor group from control group, acoustic intensity contours and airflow time waveforms were highly and positively correlated in more tremor subjects (90%) than control subjects (40%). This finding suggests that the relationship between acoustic intensity contours and airflow time waveforms may reflect the presence and the source of voice tremor.

Acoustic spectral analysis of three tornadoes

Three sound recordings of tornadoes have been spectrally analyzed over the frequency interval between 100 and 2000 Hz. The low-frequency analysis was limited by the response of the microphones used for the recordings; the upper frequency limit was imposed both the microphone response and the low-signal level. One recording was made by James Cramer of a tornado which passed through Clay Center, Kansas on 25 September 1973. A second recording was made by Richard Allen Lindley of a tornado that passed through Guin, Alabama on 3 April 1974, and a third recording was made by Tom Bittman of a tornado which damaged his home in Tulsa, Oklahoma on 8 June 1974. All of the recordings are of low quality and the audio information required major spectral corrections, but the data analysis does indicate that the audio emissions from the tornadoes decrease in intensity as a function of increasing frequency. An attempt has been made to correlate the data with real (and conjectured) physical characteristics of the tornadoes and attendent atmospheric phenomena. It is clear to us from an objective analysis (and the more difficult subjective evaluation of the recordings) that identification of tornadoes based on acoustic emissions is possible . A study of tornadic sounds can not only provide a new tool for gaining insight into electrical and mechanical disturbances within a tornadic storm, but will also allow acoustic detection of a tornadic storm. A study of the change in intensity of the sounds emitted by the approaching Guin storm at both high and low frequencies suggests that noises generated by the high-speed winds of the principal tornado vortex as its base scoured the ground might be discerned from noises generated by the winds of one or more smaller vortices moving around the tornado, and/or electrical discharges aloft. Subject Classification: [43]28.45, [43]28.65.

Acoustic spectral analysis of three tornadoes

Three sound recordings of tornadoes have been analyzed over the frequency interval between 100 and 2000 Hz. The low-frequency analysis was limited by the spectral response of the microphones, and the upper limit was imposed both by the microphone response and the low signal level. Although the recordings are of low quality and the audio information required major spectral corrections, the data do indicate that the recorded audio emissions from the tornadoes decrease in intensity as a function of increasing frequency. An attempt has been made to correlate the spectra with real (and conjecture) physical properties of the tornadoes. It is clear to us from our objective analysis (and the more difficult subjective evaluation of the recordings) that audible identification of tornadoes is possible, and a study of tornadic sounds might provide a new tool for gaining insight into electrical and mechanical disturbances within a tornado's funnel system. Study of the change in intensity of the sounds emitted by the approaching Guin storm at both high and low frequencies suggests that noises generated by the high speed winds of the tornado cyclone as it scours the ground can be discerned from noises associated with the winds and/or electrical discharges aloft.

Computer Synthesis of Acoustic Processor Performance

The technique of acoustic spectral analysis by use of a recirculating delay line has been reported in the literature by J. Capon and others. This technique involves summation of M samples in a delay-line loop, in which successive samples are frequency shifted by an amount equal to the reciprocal of the delay time. Performance degradation occurs when there is a mismatch between the incremental frequency shift and the loop delay. This paper examines the quantitative effect of this mismatch upon processor performance. A computer model is developed and its performance perturbed by introducing a parametric series of design tolerances. The computer model is analyzed from two separate approaches, a deterministic and a probabilistic method. Effects on system Q and the number of recirculated samples M are presented.