Within the MARCET European project and community framework, a Waveglider®™ SV2 vehicle was deployed, equipped with a passive acoustic monitoring (PAM) device, in a Special Area of Conservation (SAC) ...of Gran Canaria (Canary Islands, Spain). The soundscape was continuously recorded from 23 July 2018 until 30 July 2018 and was primarily used for marine mammal sound detection. This study aims to compare these automatically embedded detections from the Waveglider®™ with human expert detections. Furthermore, it provides an assessment of the performance of the automatic detector and discusses the use of this type of technology to monitor wildlife, particularly cetaceans. The MARCET project and this study are only possible due to the multidisciplinary integration of veterinary sciences, ecological, zoological, and biological knowledge and mechanical, communication, and electronics engineering. It represents an excellent example of new technologies, capacities, skills, and cutting-edge knowledge where veterinary science education and training should progressively be involved to contribute to the surveillance and control of ocean health.
•Under human care dolphins use echolocation towards immersed non-alimentary objects.•Acceleration of the Inter-Click-Interval (ICI) in approach phase.•ICI deceleration before touch of the object ...takes over from echolocation.•No sound production while contact lasts.
Odontocetes modulate the rhythm of their echolocation clicks to draw information about their environment. When they approach preys to capture, they speed up their emissions to increase the sampling rate of “distant touch” and improve information update. This global acceleration turns into a “terminal buzz” also described in bats, which is a click train with drastic increase in rate, just as reaching the prey. This study documents and analyses under human care bottlenose dolphins’ echolocation activity, when approaching non-alimentary targets. Four dolphins’ locomotor and clicking behaviours were recorded during training sessions, when sent to immersed objects pointed by their trainers. Results illustrate that these dolphins profusely use echolocation towards immersed non-alimentary objects. They accelerate click emission when approaching the target, thus displaying a classical terminal buzz. However, their terminal buzz slackens off within a quarter of second before the end of click train. Typically, they decelerate to stop clicking just before they touch the object using their rostrum lower tip. They do not emit clicks as the contact lasts. In conclusion, when exploring inert objects, bottlenose dolphins under human accelerate clicking like other odontocetes or bats approaching preys. Bottlenose dolphins’ particular slackening-off profile at the end of the buzz shows that they anticipate the moment of direct contact, and they stop just as real touch relays distant touch of the object.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Les ondes acoustiques subissent peu de dispersion dans le milieu marin, comparé au milieu aérien. Certaines espèces de cétacés communiquent ainsi à grande distance, d'autres utilisent leurs émissions ...sonores pour s'orienter. La bioacoustique consiste à étudier ces espèces à partir de l'analyse de leurs sons, c'est-à-dire à les détecter, classer, localiser. Cela peut se faire via un réseau d'hydrophones au déploiement fastidieux. Afin de contribuer au passage à l'échelle de la bioacoustique, cette thèse propose des modèles originaux mono-hydrophone pour l'analyse de ces signaux stationnaires ou transitoires. Premièrement, nous dérivons un nouveau modèle d'estimation de la distance entre une source impulsive (ex. biosonar) et un hydrophone. Notre modèle théorique, l'Intra Spectral ATténuation(ISAT), dérive des lois acoustiques de déformation spectrale du signal transitoire induite par l'atténuation durant sa propagation. Ce modèle relie les rapports énergétiques des bandes de fréquences pondérés par un modèle de perte par atténuation fréquentielle (Thorp ou Leroy) à la distance de propagation. Nous approximons aussi ISAT par un modèle neuromimétique. Ces deux modèles sont validés sur le sonar du cachalot (Physeter macrocephalus) enregistré avec notre bouée acoustique autonome BOMBYX et notre système d'acquisition DECAV en collaboration avec le Parc National de Port-Cros et le sanctuaire Pelagos pour la protection des mammifères marins en Méditerranée. Les mesures d'erreur (RMSE) d'environ 500 mètres sur nos références du centre d'essai OTAN aux Bahamas présentent un intérêt opérationnel. Deuxièmement, nous proposons une analyse originale de l'évolution des voisements de cétacé par codage parcimonieux. Notre encodage des cepstres par apprentissage non supervisé d'un dictionnaire met en évidence l'évolution temporelle des bigrammes des chants que les baleines à bosse mâles émettent durant la période de reproduction. Nous validons ce modèle sur nos enregistrements du canal de Sainte-Marie à Madagascar entre 2008 et 2014, via notre réseau d'hydrophones BAOBAB qui constitue une première dans l'Océan Indien. Nos modèles s'inscrivent dans le projet Scaled Bioacoustics (SABIOD, MI CNRS) et ouvrent de nouvelles perspectives pour les passages à l'échelle temporelle et spatiale de la bioacoustique.
Acoustic waves show low dispersion due to the underwater propagation, compared to the propagation in the air. Some species of cetaceans communicate at long distance, others use their sound production for orientation. The goal of the scientic area called bioacoustics is to study animal species based on the analysis of their emitted sound. Their sounds can be used to detect, to classify and to locate the cetaceans. Recordings can be done with an passive acoustic array of multiple hydrophones, but this method is expensive and difficult to deploy. Thus, in order to scale this approach, we propose in this Phd thesis several original single hydrophone models to analyze these stationary or transient signals.Firstly, we provide a new theoretical model to estimate the distance between the impulsive source (ex. biosonar of the cetacean) and the hydrophone. Our model, the Intra Spectral ATtenuation (ISAT), is based on the spectral signal alteration due to the underwater acoustic propagation, especially the differences in different frequency bands. We also approximated ISAT by an artificial neural network. Both models are validated on clicks emitted by sperm whales (Physeter macrocephalus) recorded by our sonobuoy BOMBYX and our data-acquisition system DECAV developed incollaboration with the National Park of Port-Cros (France) and the Pelagos sanctuary for the protection of marine mammals in the Mediterranean sea (France). The error (RMSE) measures on the recordings of the NATO test center in the Bahamas are about500 meters, promising further real applications. Secondly, we worked on the variations of the cetacean vocalizations using the sparse coding method. The encoding of thecepstrums by unsupervised learning of a dictionary shows bigrammic time changes of the songs of humpback whales (Megaptera novaeangliae). We validate this model on signals recorded in the Ste Marie Channel (Madagascar) between 2008 and 2014, through our network of hydrophones BAOBAB which is the first passive acoustic array deployed in the Indian Ocean.Our models are part of the Saled Bioacoustics project (SABIOD, MI CNRS) and open perspectives for temporal and spatial scaling of bioacoustics.
Au cours de la période de reproduction, les baleines à bosse mâles émettent des vocalises organisées et, pour certaines, répétées formant ainsi le leitmotiv d’un chant. Principalement, dans le but de ...mieux appréhender le comportement de ces baleines et notamment les interactions entre individus (mâle/mâle, mâle/femelle), plusieurs études sont actuellement menées sur ces chants. Dans cette étude, nous nous intéressons aux unités sonores, vocalises séparées par 2 silences, qui composent ces chants, à leurs récurrences, et à leurs structurations. Cependant, tous ces paramètres dépendent de l’année et du lieu d’enregistrement. Des travaux antérieurs ont souligné la nécessité de méthodes objectives pour la classification de ces unités sonores. L’analyse détaillée des vocalisations a montré que les caractéristiques d’une unité peuvent changer brusquement pendant toute sa durée, ce qui les rend difficiles à caractériser et à grouper systématiquement. Cet article propose un codage parcimonieux des chants afin de déterminer leurs composantes stables de celles qui varient, pour différentes échelles de temps. Une définition de la complexité du code est également proposée afin de séparer les composantes du chant du bruit mer. Notre méthode est illustrée sur un chant précédemment analysé. Les résultats sont donnés pour le classement d’unités sonores et aussi de sous-unités sonores, notion que notre équipe a introduite précédemment. Cette étude montre statistiquement que les codes les plus courts sont les plus stables et surviennent avec une fréquence similaire sur deux années consécutives, tandis que les plus longues unités sont clairement différentes.
Male humpback whales emit songs during the breeding season. These songs are made with successive vocalizations called sound units. The study of these songs is based on the classification of these sound units, especially to extract the song theme of the singers in a specific area during a specific season. Recently, some approaches are proposed for automatic classification of these sound units. This paper introduces the sparse coding as a robust unsupervised classifier to generate efficient time-frequency representation of the calls of the whale. Secondly, the subunit shows to be interesting to analyze the evolution ofthe humpback whale songs during two years. It is statistically shown that the shortest units are the most stable (occurring with similar time frequency shape across the two years), while the longest units are evolving from one year to one other.
The Sperm whale (Physeter macrocephalus) produces clicks of a few milliseconds composed by a sequence of short pulses. The spacing of some pulses (IPI) is a key measure to discriminate the whales and ...to assess their length. The IPI is usually estimated manually based on average autocorrelation, cepstrum or waveform. However, these methods are time-consuming and biased by the orientation of the hydrophone, thus they are unreliable for discriminating individuals. We propose a new IPI (automatic) algorithm allowing to segregate and to count precisely the whales. Using published allometric rules, this method can be used to estimate the size of each detected sperm whale, even when simultaneous recordings are made. Our algorithm has been validated, based on recordings done in the northwest of the Pelagos Sanctuary, around the Hyeres archipelago and Port-Cros national Park during the 2009-2012 DECAV research program. We demonstrate in this paper a significant improvement of the whale detection (by a factor 4 compared to visual detection), a 86% achievable determination of whales through acoustic detection of their size. We conclude with a discussion on the composition of the observed population.Original Abstract: Le cachalot (Physeter macrocephalus) emet des clics de quelques millisecondes composes d'une sequence de pulses. L'intervalle de temps entre ces pulses (IPI) depend entre autres parametres de la taille de l'animal. L'IPI est dans l'etat de l'art estime manuellement par moyenne d'auto-correlation de clics, ou par leur cepstre moyen. Couteuses en temps, ces methodes sont faussees par l'orientation du cachalot par rapport a l'hydrophone et donc imprecises, et sont peu fiables pour discriminer les individus. Nous proposons un algorithme (BIVIP) plus rapide et robuste a l'orientation de l'animal et a des emissions concomitantes de plusieurs cachalots. Les relations allometriques de la bibliographie permettent alors d'estimer la taille de chaque cachalot detecte, meme en cas d'enregistrements simultanes de plusieurs individus. BIVIP est valide sur le corpus que nous avons enregistre dans le nord-ouest du Sanctuaire Pelagos, autour des iles d'or du Parc national de Port-Cros durant le programme de recherche Pelagos DECAV 2009-2012. Nous montrons un gain significatif des contacts par acoustique comparativement au transect visuel (facteur 4 environ), ainsi qu'une faisabilite a 86 % de la determination par acoustique de la taille. Nous concluons sur une discussion de la composition de la population observee.
Bioacoustic monitoring, such as surveys of animal populations and migration, needs efficient data mining methods to extract information from large datasets covering multi-year and multi-location ...recordings. This paper introduces a method for sparse coding of bioacoustic recordings in order to efficiently compress and automatically extract patterns in data. We demonstrate the proposed method on the analysis of humpback whale songs. Previous work suggests that the structure of these songs can be characterized by successive vocalizations called sound units. Most of these analyses are currently done with expert intervention, but the volume of recordings drive the need for automated methods for sound unit classification. This paper proposes that sparse coding of the song at different time scales supports the distinction of stable song components versus those which evolve year to year. The approach is summarized as: first, an unsupervised method is used to encode the entire bioacoustic dataset into a dictionary, second, sparse coding is used to limit the number of elements in the dictionary, third, salient features are identified using the Lasso algorithm, and finally, an interpretation of the evolving and stable components of the songs is derived, supporting an analysis of year to year variation. It is shown that shorter codes are more stable, occurring with similar frequency across two consecutive years, while the occurrence of longer units varies across years as expected based on the prior manual analysis. 250 ms segments appear to be an appropriate length for encoding stable features of whale songs, possibly corresponding to subunits. We conclude by exploring further possibilities of the application of this method for biopopulation analysis.
This paper presents a spermwhale' localization architecture using jointly a bag-of-features (BoF) approach and machine learning framework. BoF methods are known, especially in computer vision, to ...produce from a collection of local features a global representation invariant to principal signal transformations. Our idea is to regress supervisely from these local features two rough estimates of the distance and azimuth thanks to some datasets where both acoustic events and ground-truth position are now available. Furthermore, these estimates can feed a particle filter system in order to obtain a precise spermwhale' position even in mono-hydrophone configuration. Anti-collision system and whale watching are considered applications of this work.
EDF scheduling using two-mode voltage-clock-scaling for hard real-time systems Lee, Yann-Hang; Doh, Yoonmee; Krishna, C. M.
International Conference on Compilers, Architecture and Synthesis for Embedded Systems: Proceedings of the 2001 international conference on Compilers, architecture, and synthesis for embedded systems; 16-17 Nov. 2001,
11/2001
Conference Proceeding
Scaling down power supply voltage yields a quadratic reduction in dynamic power dissipation and also requires a reduction in clock frequency. In order to meet task deadlines in hard real-time ...systems, the delay penalty in voltage scaling needs to be carefully considered to achieve low power consumption. In this paper, we focus on dynamic reclaiming of early released resources in Earliest Deadline First (EDF) scheduling using voltage scaling. In addition to a static voltage assignment, we propose a new dynamic-mode assignment, which has a flexible voltage mode setting at run-time enabling much larger energy savings. Using simulation results and exploiting the interplay between power supply voltage, frequency, and circuit delay in CMOS technology, we find the optimal two-level voltage settings that minimize energy consumption.
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