8 research outputs found

    Cows vocalization and behavioral characterization during eutocic and dystocic calvings

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    Oral session 3[EN] Calving is a painful and stressful event for dairy cows. Continuous monitoring can provide quick and accurate assistance to the cow, reducing stress, pain, and preventing calving difficulties (dystocia). Vocalizations can provide information on cow welfare problems, such as pain. The aims of the current study were: (1) to characterize cows' vocalizations before and during calving and (2) to determine the relationship between cow vocalizations and painrelated behavior in eutocic and dystocic calvings

    Might cows have accents? Acoustic characterization of calves vocalizations from two different geographical locations

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    Oral session 2[EN] The development of artificial intelligence algorithms and monitoring technologies has led to the increased use of sensors in animal production. Animal production stakeholders have emphasized the importance of non-invasive methods that provide accurate information without compromising the physical integrity of the animals. Animal vocalizations offer an opportunity to capture data of biological relevance without animal manipulation

    Design and validation of probes and sensors for the characterization of magneto-ionic radio wave propagation on Near Vertical Incidence Skywave paths

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    his article describes the design and validation of deployable low-power probes and sensors to investigate the influence of the ionosphere and the Earth’s magnetic field on radio wave propagation below the plasma frequency of the ionosphere, known as Near Vertical Incidence Skywave (NVIS) propagation. The propagation of waves that are bent downward by the ionosphere is dominated by a bi-refractive mechanism called ‘magneto-ionic propagation’. The polarization of both downward waves depends on the spatial angle between the Earth’s magnetic field and the direction of propagation of the radio wave. The probes and sensors described in this article are needed to simultaneously investigate signal fading and polarization dynamics on six radio wave propagation paths. The 1-Watt probes realize a 57 dB signal-to-noise ratio. The probe polarization is controlled using direct digital synthesis and the cross-polarization is 25–35 dB. The intermodulation-free dynamic range of the sensor exceeds 100 dB. Measurement speed is 3000 samples/second. This publication covers design, practical realization and deployment issues. Research performed with these devices will be shared in subsequent publications

    Separation of Ambient Radio Noise and Radio Signals Received via Ionospheric Propagation

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    Systems for atmospheric research and wireless communication use the High Frequency (HF) ra-dio spectrum. At these frequencies, typically up to 20 MHz, the ambient electromagnetic noise is stronger than the noise generated by the receiver itself, thereby limiting the sensitivity of the instruments. Especially in urban areas, the noise level is high. In remote rural environments, where artificial noise sources are absent, a much lower noise level is observed. It has been shown that this noise arrives via ionospheric propagation and consists of impulsive noise from lightning and a background component that resembles additive white Gaussian noise. To estab-lish the absolute field strength of this background noise component, a direction- and polariza-tion-agnostic antenna is realized by adding the power of two orthogonal antenna elements in the digital domain. To suppress radio signals arriving via ionospheric propagation—of which the spectral and temporal aspects are not known a priori—a novel adaptive filter is demonstrat-ed that separates the background noise from the radio signals in the joint frequency-time do-main. This method is demonstrated using measurements from a polarimetric experiment on 7 MHz in a remote rural area in Catalonia. The results are submitted to the International Tele-communication Union for the validation of ambient noise models

    A transportable hybrid antenna-transmitter system for the generation of elliptically polarized waves for NVIS propagation research

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    For empirical research on Near Vertical Incidence Skywave (NVIS) characteristic wave propagation, a beacon transmitter system is needed that can be programmed to emit precisely defined elliptically and circularly polarized waves at high elevation angles. This paper proposes a novel hybrid antenna-transmitter system, a combination of a synchronous dual channel transmitter and a turnstile antenna. The polarization emitted by the turnstile antenna is defined by the power ratio and phase difference of the outputs of the transmitter. Operating frequency is between 3 to 10 MHz. An automated and transportable solution is described, which can be fed by battery or solar power. Power consumption is 5.7 W
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