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Literatura académica sobre el tema "Acoustic wake-up systems"

Autor: Grafiati

Publicado: 25 de mayo de 2024

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Artículos de revistas sobre el tema "Acoustic wake-up systems"

Yang, Deng y Jiahao Zhao. "Acoustic Wake-Up Technology for Microsystems: A Review". Micromachines 14, n.º 1 (3 de enero de 2023): 129. http://dx.doi.org/10.3390/mi14010129.

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Microsystems with capabilities of acoustic signal perception and recognition are widely used in unattended monitoring applications. In order to realize long-term and large-scale monitoring, microsystems with ultra-low power consumption are always required. Acoustic wake-up is one of the solutions to effectively reduce the power consumption of microsystems, especially for monitoring sparse events. This paper presents a review of acoustic wake-up technologies for microsystems. Acoustic sensing, acoustic recognition, and system working mode switching are the basis for constructing acoustic wake-up microsystems. First, state-of-the-art MEMS acoustic transducers suitable for acoustic wake-up microsystems are investigated, including MEMS microphones, MEMS hydrophones, and MEMS acoustic switches. Acoustic transducers with low power consumption, high sensitivity, low noise, and small size are attributes needed by the acoustic wake-up microsystem. Next, acoustic features and acoustic classification algorithms for target and event recognition are studied and summarized. More acoustic features and more computation are generally required to achieve better recognition performance while consuming more power. After that, four different system wake-up architectures are summarized. Acoustic wake-up microsystems with absolutely zero power consumption in sleep mode can be realized in the architecture of zero-power recognition and zero-power sleep. Applications of acoustic wake-up microsystems are then elaborated, which are closely related to scientific research and our daily life. Finally, challenges and future research directions of acoustic wake-up microsystems are elaborated. With breakthroughs in software and hardware technologies, acoustic wake-up microsystems can be deployed for ultra-long-term and ultra-large-scale use in various fields, and play important roles in the Internet of Things.

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Schmidt, Jan H. y Aleksander M. Schmidt. "Wake-Up Receiver for Underwater Acoustic Communication Using in Shallow Water". Sensors 23, n.º 4 (13 de febrero de 2023): 2088. http://dx.doi.org/10.3390/s23042088.

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A data frame transmitted over the underwater acoustic channel usually begins with a preamble. Therefore, underwater communication systems have a dedicated receiver that constantly listens to the preamble signals. A receiver that is to work effectively in shallow waters must have solutions that effectively reduce the impact of the permanently occurring multipath propagation. The article presents a solution based on complementary broadband signals. Initial tests were carried out using the Watermark simulator to determine its reliability in such a difficult propagation environment. The results of experimental tests carried out in a model pool are also included. Details of the implementation of the wake-up receiver are presented.

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Gazivoda, Marko, Dinko Oletić y Vedran Bilas. "Features and Always-On Wake-Up Detectors for Sparse Acoustic Event Detection". Electronics 11, n.º 3 (6 de febrero de 2022): 478. http://dx.doi.org/10.3390/electronics11030478.

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The need to understand and manage our surroundings has led to increased interest in sensor networks for the continuous monitoring of events and processes of interest. To reduce the power consumption required for continuous monitoring, dedicated always-on wake-up detectors have been designed, with an emphasis on their low power consumption, simple and robust design, and reliable and accurate detection. An especially interesting application of these wake-up detectors is in detecting acoustic signals. In this paper, we present a study on the features and detectors applicable for the detection of sporadic acoustic events. We perform a state-of-the-art acoustic detector analysis, grouping the detectors based on the features they utilize and their implementations. This analysis shows that acoustic wake-up detectors predominantly utilize spectro-temporal (56%) and temporal features (36%). Following the state-of-the-art analysis, we select two detector architecture candidates for a case study on passing motor vehicle detection. We utilize our previously developed spectro-temporal decomposition detector and develop a novel level-crossing rate detector. The results of the case study shows that the proposed level-crossing rate detector has lower component count (44 compared to 70) and power consumption (9.1 µW compared to 34.6 µW) and is an optimal solution for SNRs over 0 dB.

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Marzetti, Sebastián, Valentin Gies, Paul Best, Valentin Barchasz, Sébastien Paris, Hervé Barthélémy y Hervé Glotin. "A 30 μW Embedded Real-Time Cetacean Smart Detector". Electronics 10, n.º 7 (30 de marzo de 2021): 819. http://dx.doi.org/10.3390/electronics10070819.

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Cetacean monitoring is key to their protection. Understanding their behavior relies on multi-channel and high-sampling-rate underwater acoustic recordings for identifying and tracking them in a passive way. However, a lot of energy and data storage is required, requiring frequent human maintenance operations. To cope with these constraints, an ultra-low power mixed-signal always-on wake-up is proposed. Based on pulse-pattern analysis, it can be used for triggering a multi-channel high-performance recorder only when cetacean clicks are detected, thus increasing autonomy and saving storage space. This detector is implemented as a mixed architecture making the most of analog and digital primitives: this combination drastically improves power consumption by processing high-frequency data using analog features and lower-frequency ones in a digital way. Furthermore, a bioacoustic expert system is proposed for improving detection accuracy (in ultra-low-power) via state machines. Power consumption of the system is lower than 30 μW in always-on mode, allowing an autonomy of 2 years on a single CR2032 battery cell with a high detection accuracy. The receiver operating characteristic (ROC) curve obtained has an area under curve of 85% using expert rules and 75% without it. This implementation provides an excellent trade-off between detection accuracy and power consumption. Focused on sperm whales, it can be tuned to detect other species emitting pulse trains. This approach facilitates biodiversity studies, reducing maintenance operations and allowing the use of lighter, more compact and portable recording equipment, as large batteries are no longer required. Additionally, recording only useful data helps to reduce the dataset labeling time.

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Brungart, Timothy A., Eric C. Myer, Dean E. Capone, Robert L. Campbell y Howard L. Petrie. "Hydrofoil Leading Edge Isolation for Vibration and Noise Reduction in Marine Systems". Journal of Vibration and Acoustics 128, n.º 6 (5 de julio de 2006): 772–77. http://dx.doi.org/10.1115/1.2346697.

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A technique for reducing the vibration and noise from hydrofoils subject to unsteady lift is examined experimentally. Since the unsteady lift is known to be concentrated in the leading edge vicinity, a single-stage vibration isolation mount is integrated into a hydrofoil near its leading edge to inhibit the leading edge-generated unsteady forces from being transmitted to the remainder of the foil and any structures coupled to it. A single layer of elastomer forms the mount and is used to isolate the leading 20% chord of the hydrofoil from the remainder of the structure. The hydrofoil is excited into vibration by turbulence from an upstream wake generator in a water tunnel facility. Compared to a nonisolated hydrofoil, vibration reductions up to 10dB in level are recorded on the portion of the hydrofoil isolated from the leading edge.

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Michetti, Giuseppe, Luca Colombo, Gabriel Giribaldi, Ankit Mittal, Hussain Elkotby, Ravikumar Pragada, Aatmesh Shrivastava y Matteo Rinaldi. "A Micro-Acoustic Enhanced Low-Impedance Antenna System for IoT Wake-Up Receivers". IEEE Internet of Things Journal, 2023, 1. http://dx.doi.org/10.1109/jiot.2022.3233355.

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Zhang, Yamin. "Deep neural networks for multimodal perception and human-computer interaction technology in art design". Applied Mathematics and Nonlinear Sciences, 21 de octubre de 2023. http://dx.doi.org/10.2478/amns.2023.2.00702.

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Abstract The first part of this paper examines the aesthetic and application advantages of art design using human-computer interaction technology and develops a multimodal perceptual human-computer interaction system for art design. Multimodal data is obtained using multi-scale convolutional kernels for acoustic feature extraction and deep convolutional neural networks for multiple interaction image feature fusion. Finally, a test analysis is conducted to verify the system's effectiveness in this paper. According to the results, the system has an average wake-up success rate of 99.51% and a wake-up response time of 0.3665 seconds. Implementing human-computer interaction technology and deep neural networks in art design is effective and promotes the development of art design.

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Saravana Prabahar, Nimal Sudhan, Sam Fredriksson y Göran Broström. "Comparison of Actuator Line Modelling of Tidal Power Kites with ADCP Measurements". Proceedings of the European Wave and Tidal Energy Conference 15 (2 de septiembre de 2023). http://dx.doi.org/10.36688/ewtec-2023-544.

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The potential for tidal energy to be a part of future renewable energy systems is expanding. Tidal turbines deployed in open waters or channels are effective methods to harness energy from tidal currents. Sharing similar functionality with wind turbines, horizontally mounted tidal turbines require a minimum tidal current velocity to operate effectively. The Deep Green (DG) power plant which is based on a tethered kite model aims, however, to operate efficiently in tidal current velocities as low as 1.2 m/s. The kite wing is steered in a lemniscate trajectory ( ) almost perpendicular to the tidal current. In the trajectory, the relative flow velocity through the turbine attached to the wing reaches several times the tidal current velocity, enabling efficient operation of the turbine in relatively low-velocity tidal currents. This could reduce geographical limitations in installing large-scale tidal power arrays. In a previous project, numerical modelling of the DG was carried out in a tidal flow using Large Eddy Simulations (LES) and Actuator Line Modelling (ALM) implemented in OpenFOAM solver. ALM using momentum sources has been used in modelling wind turbines and has been validated against experimental data and observations. The ALM has been further developed in order to be able to model wings (here the kite) that move in arbitrary paths compared to horizontally mounted turbines with rotational paths. This numerical model for the DG kite in a tidal flow has, however, up to now not been validated against observations, which is beneficial before further analyses are made, e.g., optimization studies. In this study, Acoustic Doppler Current Profiler (ADCP) observations taken in the wake of a DG are compared to the results from the numerical model under similar conditions. Comparing the numerical results directly with the observations leads to discrepancies, hence the model data is resampled in a similar way that the ADCP would measure and process data using a virtual ADCP for the model. Flow properties such as the instantaneous and time-averaged stream velocities are in turn compared for both the tidal flow without the DG and with a DG. The effect of the DG on the tidal flow is analysed using the model and the observations. After resampling the model data, the model and observations show good agreement. This suggests 1) that the DG model using ALM can be used for further analysis and 2) that whilst comparing model data with ADCP observations for studying the small-scale effects of tidal turbine wakes, care should be taken to sample the model data consistently with observations.

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Actas de conferencias sobre el tema "Acoustic wake-up systems"

Sanchez, A., S. Blanc, P. Yuste y J. J. Serrano. "RFID Based Acoustic Wake-Up System for Underwater Sensor Networks". En 2011 IEEE 8th International Conference on Mobile Ad-Hoc and Sensor Systems (MASS). IEEE, 2011. http://dx.doi.org/10.1109/mass.2011.103.

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Li, Haiyu, Deqing Wang, Yongjun Xie y Xiaoyi Hu. "A LFM-based adaptive wake-up signal detection approach for underwater acoustic communication system". En WUWNet'18: The 13th ACM International Conference on Underwater Networks & Systems. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3291940.3291962.

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Fourniol, Manon, Valentin Gies, Valentin Barchasz, Edith Kussener, Herve Barthelemy, Remy Vauche y Herve Glotin. "Analog Ultra Low-Power Acoustic Wake-Up System Based on Frequency Detection". En 2018 IEEE International Conference on Internet of Things and Intelligence System (IOTAIS). IEEE, 2018. http://dx.doi.org/10.1109/iotais.2018.8600849.

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Abughannam, Saed y J. Christoph Scheytt. "System Analysis of a Wake-Up Receiver Based on Surface Acoustic Wave Correlator". En 2018 2nd URSI Atlantic Radio Science Meeting (AT-RASC). IEEE, 2018. http://dx.doi.org/10.23919/ursi-at-rasc.2018.8471531.

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Thurman, Christopher, Nikolas Zawodny y James Baeder. "Computational Prediction of Broadband Noise from a Representative Small Unmanned Aerial System Rotor". En Vertical Flight Society 76th Annual Forum & Technology Display. The Vertical Flight Society, 2020. http://dx.doi.org/10.4050/f-0076-2020-16492.

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This work details the application of a lattice-Boltzmann method-very-large-eddy simulation (LBM-VLES) employed by the software suite, PowerFLOW. This LBM-VLES simulation predicted the aeroacoustic noise emanating from a representative, small unmanned aircraft system rotor, namely, the DJI-9450 in a hover condition. Predicted total aerodynamic loading as well as 2D aerodynamic loading along discrete spanwise sections of a rotor blade were compared to lower fidelity predictions and experimental results acquired in the Structural Acoustic Loads and Transmission anechoic chamber facility at the NASA Langley Research Center. The total acoustic spectra were decomposed into tonal and broadband components, which showed that broadband noise was a dominant contributor above 1 kHz for this rotor. These data were then compared to experimentally acquired data, showing good agreement up to approximately 11 kHz. Above 11 kHz, however, a grid sensitivity study showed dependency of the highest resolvable frequency on the spatial resolution of the computational domain, explaining the roll off in predicted data. Individual broadband noise sources were further investigated by calculating one-third octave sound pressure levels of the unsteady pressure fluctuations acting on the rotor, providing evidence that blade self-noise was the prominent noise source. Using these results, blade wake interaction noise was seen to be negligible for this particular rotor, which was further validated by calculating blade vortex miss distances and comparing to theory.

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Weiland, Chris y Pavlos Vlachos. "Analysis of the Parallel Blade Vortex Interaction With Leading Edge Blowing Flow Control Using the Proper Orthogonal Decomposition". En ASME/JSME 2007 5th Joint Fluids Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/fedsm2007-37275.

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Interactions of vortical unsteady flows with structures are often encountered in several engineering applications. Such flow structure interactions (FSI) can be responsible for generating significant loads and can have many detrimental structural and acoustic side effects, such as structural fatigue, radiated noise and even catastrophic results. Amongst the different types of FSI, the parallel Blade-Vortex Interaction (BVI) is one of the most prominent. The authors in a previous work (Weiland and Vlachos, 2006) reported an active flow control technique that successfully minimizes the parallel BVI. This technique is based on disrupting the incident vortex using a jet issued via Leading Edge Blowing (LEB), hence, hereon we term the method LEB. The effectiveness of the method was experimentally analyzed using Time-Resolved Digital Particle Image Velocimetry (TRDPIV) recorded at a rate sufficient to fully resolve the spatio-temporal dynamics of the flow field combined with simultaneous accelerometer measurements of the structure. These measurements quantitatively document the FSI dynamics. While our results demonstrated that for the range of our experimental parameters the LEB is successful in dramatically modifying the BVI, the question still remains as to which physical processes are responsible for this reduction. This paper represents a continuation of our effort to further understand the dynamics of using active flow control to mitigate BVI. We present Proper Orthogonal Decomposition (POD) analysis of the temporally resolved planar flow fields for two extreme cases that were reported in the previous work. The two cases correspond to a large wake generator and a small wake generator. The POD technique was chosen specifically for its ability to reduce a complicated flow field into its optimal fundamental modes with a description of the energy contained in each mode, thereby simplifying the dynamics of a flow-field system for analysis. Results of the POD analysis for the small wake generator indicate that for no LEB, the fundamental (i.e. most energetic) mode is given by the vortex shedding of the circular cylinder upstream. The addition of LEB reduces the energy contained in this fundamental mode. Thus the LEB jet has the effect of reducing the flow field coherency; the structure of the exciting vortices is broken up into smaller vortices which have less or little effect on the transfer of energy from the wake to the airfoil. For the case of the large wake generator, the LEB jet has the opposite effect: the jet organizes the circular cylinder wake into flow structures that maintain their form, and thus the wake retains its ability to excite the airfoil into vibrations.

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Druzhinin, Iaroslav, Victor Mileshin y Vladimir Korzhnev. "Numerical and Experimental Investigation of Aerodynamic Characteristics of Model Ultra High Bypass Ratio Counter Rotating Fan". En ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-76861.

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One of the perspective schemes of air breathing engine is a scheme with Ultra High Bypass Ratio (BPR 16...25) Counter Rotating Fan. This solution potentially allows significant increase of fuel efficiency compared to modern conventional turbofans. The model UHBR counter rotating fan named COBRA-1 was developed by CIAM within the framework of European Project COBRA (Innovative Counter rOtating fan system for high Bypass Ratio Aircraft engine). The fan was designed using up-to-date 1D, 2D and 3D methods. COBRA-1 is a 0.7 m diameter model of counter rotating fan driven by a planetary reduction gearbox. The bypass ratio of COBRA-1 is 20. The R2/R1 torque ratio was chosen to obtain 1.42-muliple prevalence in power for 2nd row. The blade numbers are 8/12 for R1/R2 correspondingly. Final geometry of airfoils was defined by 3D profiling process to achieve required aerodynamics and acoustic parameters. Application of control-diffusion airfoils allows reaching high integral performances: specific mass flow equals 211 kg/(s*m^2) and isentropic efficiency at design point is higher than 0.93. The paper presents results of computational simulation of the flow in UHBR fan COBRA-1 based on 3D steady RANS method, 3D URANS and Non-Linear Harmonic method for different operation conditions in comparison with experimental data. Numerical simulation was carried out using Numeca FINE TURBO software package. Steady RANS approach was used during design process to make quick estimation of performances at different rpm. 3D URANS simulation was conducted to analyze unsteady wake-blade and shock-wave interaction and to make a decision about sufficient value of axial gap between rotors. The COBRA-1 fan was tested in CIAM at C3-A test facility which allows conducting a wide range of measurements of local and integral parameters including acoustics of ducted counter rotating fan at different operating conditions. Experimental results demonstrate a high level of integral performances and good agreement with computed values. Significant part of numerical and experimental investigation is devoted to effect of gear-box requirements on aerodynamics. C3-A rig allows to set rotational speed of rotors independently and measure torques at each shaft to achieve required torque ratio and study the influence of small (3–5%) deviation in rpm on aerodynamic characteristics.

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