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In this paper, matched-field localization with a single vector hydrophone is researched. In condition of ideal waveguide, the sound pressure field and vertical velocity were analyzed theoretically. The relationship between acoustic pressure field and vector field achieved that a vector hydrophone can be equivalent to vertical two element array with a certain vertical aperture. The depth of vector...
Humans infer rich knowledge of objects from both auditory and visual cues. Building a machine of such competency, however, is very challenging, due to the great difficulty in capturing large-scale, clean data of objects with both their appearance and the sound they make. In this paper, we present a novel, open-source pipeline that generates audiovisual data, purely from 3D object shapes and their...
Here, we present an affordable Augmented Reality (AR) based system to quantify postural stability of an individual which can be used in tele-rehabilitation and personalized health care applications. Postural instability is a prominent symptom of many physiological disorders and is a major precursor of fall risk. Conventional stability scoring techniques require presence of physiotherapist and are...
This paper introduces sparse low-power sensor networks using passive seismic sensors for crowd-aware smart buildings, resulting in an “Internet of Ears (IoE)” that can hierarchically detect human footsteps, estimate walk direction, and track person position. An energy-based thresholding footstep detector was developed using wavelet transform for pre-filtering the noise-prone ambient vibrations detected...
This paper presented a numerical simulation of an electrochemical seismometer, which provided an effective approach to study its transfer functions. The fluid-solid coupling model was firstly used in this paper to establish the link between the external vibrations and the internal velocities of the liquid inertial mass of the electrochemical seismometer. Some key parameters in the numerical simulation...
In this paper, a secure acoustic communication system using a loudspeaker, vibration motor and microphone is proposed. The transmitter (smartphone) transmits an encrypted message and the encryption key from the loudspeaker and the vibration motor, respectively. While the sound emitted from the loudspeaker propagates long distances, the vibration emitted from the vibration motor propagates short distances...
Humans can distinguish between objects of different hardness by tapping on their surfaces. The frequency and amplitude of the damped natural vibration caused by tapping are known to be cues for the perception of hardness. However, the relationship between them has yet to be entirely understood. We performed a psychophysical experiment using the method of adjustment, wherein participants adjusted the...
This paper proposes a sensorless chatter detection method for a ball screw drive system used in milling, by introducing the mechanical energy factor (MEF). The MEF is an indicator for detecting self-excited chatter, based on the power factor theory used in electric systems, and monitors the phase difference between dynamic cutting force and displacement. By monitoring the MEF, the self-excited chatter...
In underground low-pressure gas pipelines, a leak may result in a complication more dangerous and difficult to detect, known as the water ingress problem. Groundwater enters the gas pipeline through a crack, and eventually blocks the gas flow. Vibration sensors are used to detect the water ingress problem. The sensor output indicates a marked increase in the occurrence of spikes from the vibration...
Structural Health Monitoring (SHM) is one of the most interesting research topics into civil engineering field. SHM consists of the processing and interpretation of the acquired data of a structure in order to evaluate its condition. An accurate early damage detection is an important task in SHM, as a reduction of both required time and repairing costs can be achieved. One of the most common damage...
Chatter vibration highly limits the accuracy and the material removal rate of numerical control (NC) machining operations. In this paper, an adaptive spindle speed selection method, based on an analysis using the semi-discretization method, is proposed to avoid and minimize chatter vibration in high-precision NC machining. Moreover, the proposed method is robust to modeling uncertainty and changing...
This paper presents a prototype of magnetostrictive material-based vibration energy harvester, which is used to generate electricity during human walking with high power density. According to Villari effect (inverse-magnetostrictive effect), the harvester consists of a coil-wound magnetostrictive rod. In order to improve the harvesting effect, a magnetostrictive/electromagnetic hybrid configuration...
In view of the support vector machine (SVM) model applied in vibrant fault diagnosis for hydro-turbine generating unit, it exists problems of parameter settings and classification-plane incline due to unequal sample, which leads to lower diagnosis accuracy. As a new bionic intelligent optimization algorithm for glowworm swarm optimization(GSO), it has the characteristics of strong versatility and...
The paper presents a mathematical model of a piston compressor which is a part of an oxygen gas generator. Taking into account the structural parameters of the compressor, as well as the suction and pressurization valves, such model allows one to obtain the dynamics of the pressure amplitude under the compressor's piston with the vibration velocity and vibration acceleration that are transmitted in...
In this work Integral Force Feedback and Multiple Positive position Feedback techniques are evaluated in active vibration suppression of a flexible beam. Integral Force Feedback (IFF) and Multiple Positive Position Feedback (MPPF) are independently applied as the controlling inputs to a PZT patch actuator attached to the flexible beam. Finite Element and modal models of the flexible beam are then...
According to the concept of electromagnetic aeroelastic energy harvesting system, two kinds of magnetic levitation-based electromagnetic energy conversion devices with different winding schemes are designed, and the flutter is simulated by the simple harmonic motion with given amplitude and frequency. The energy conversion capacity of this device was calculated and analyzed. The output voltage and...
Vibration monitoring and analysis is a powerful and recommended tool for preventive maintenance and early detection of impending failures in rotary machine. The demand for cost efficient, reliable and safe rotating machinery requires accurate fault diagnosis, classification and prognosis systems. This work presents a study to explore the performances of bearing fault diagnosis by using wavelet neural...
Vibrotactile systems are convenient solutions for managing interaction between automatic control systems and humans. This paper develops a vibrotactile assistance system (VAS) for high performance bicycles. The system is designed to assist the rider during braking in order to minimize the time to stop, increasing performances and safety. The proposed control architecture is the result of the low cost...
It is necessary to monitor the operation state of the High voltage circuit breaker (HVCB) and analyze the fault by the related signal, the fault of HVCB operating mechanism is closely associated with coil current, mechanical vibration and other factors. The method of fault diagnosis for HVCB based on Hilbert-Huang transform (HHT) and support vector machine is proposed to analyze faults accurately...
Fault detection and diagnosis is a research area that has a significant impact due to commercial and industrial implications. The study presented in this paper is based on the idea that mathematical models can be assigned to any processes so, in this context, we have started from the assumption that the fault monitoring and detection in industrial processes could be made using frequency model of the...
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