1,720,963 research outputs found
I vertebrati della collezione A. Vencherutti. Museo naturalistico F. Minà Palumbo di Castelbuono.
No full textAdaptive plasticity of blue tits (parus caeruleus) and great tits (parus major) breeding in natural and semi-natural insular habitats
No full textThe breeding performance and foraging of blue and great tits, and the abundance of arthropods living on the trees of an oak-wood and of a coniferous reafforestation were studied in Sicily, in order to: 1) compare breeding parameters in natural and semi-natural habitats within the same area; 2) estimate the degree of overlap in peak resource and peak demand of young tits, and the overlap of nestling diet of the two species in the two habitats. Both species had earlier laying dates, laid more eggs and raised more fledglings in the oakwood than in the reafforestation; they achieved the same fledging success within the same habitat type. These differences are probably due to the earlier and higher food peak in oak compared to pine. Food brought to the nestlings differed between habitats and between species: blue tits always brought small prey from a limited number of taxa, while great tits changed both prey taxa and size depending on habitat. The more flexible food of the great tit is in line with the smaller reduction in number of fledglings in pine reafforestation compared to oak-wood. It is suggested that tits have developed a mechanism to lay eggs at different dates in accordance with the habitat resource where adults catch prey for nestlings. Finally, mean clutch sizes of blue tits between habitats were well correlated, but the process seemed different in the great tit. Significant correlation was indeed detected between the proportion of great tits breeding in oakwood and the difference in the clutch size between the habitats. This suggests that more great tits settled in oakwood in years when conditions were more suitable to produce bigger clutches. © 2004 Taylor & Francis Group, LLC
Microcontroller Based Edge Computing for Pipe Leakage Detection
No full textIn the embedded system field a correct resource management is crucial, especially in systems that use Machine Learning (ML) algorithms. The resources in that case are in terms of memory, footprint and time used to compute the tasks. The system should be able to be both accurate and compact although the precision is directly proportional to the memory used to storage data. In this paper we describe a comparison between three ML models implemented in a microcontroller, with an application scenario devoted to monitor a Water Distribution Network by using vibrations input and trying to investigate the computational complexity of each tested solution
A distributed analysis of vibration signals for leakage detection in Water Distribution Networks
Full text linkIt is well known that Water Distribution Networks (WDNs) are very inefficient and, in Italy, 40% of water is lost during distribution. In this paper, we present a solution for detecting leakages in WDNs, based on three main components: i) an innovative sensing element to be deployed at the sensor nodes, which analyses vibrations in the acoustic range for classifying external noise sources, induced by water leakages, by means of suitable machine learning techniques; ii) an Internet of Things (IoT) system of sensors, deployed at the junctions of the WDNs, for comparing the measurements collected at different critical points of the network; iii) a machine learning algorithm for processing the data. After the definition of the WDN structure, we introduce some numerical simulation tools suitable for studying our system and modeling the proposed sensing solution. Given the geometry, physical properties (pipe lengths, diameters, roughness, reservoir shapes and levels, pump and valve characteristic curves) and nodal demands, the simulation tool is able to compute leakages in pipes or nodes over time. In parallel, we simulate our IoT system coupled to the WDN, by logging partial information about the WDN status, which corresponds to the demand readings at the edge nodes or at some junction nodes, together with the (optional) measurements of the deployed sensing elements. On the basis of this data, we analyze the possibility of identifying the leakages in the network, even without knowing the exact or complete topology of the WDN. Our solution exploits different machine learning techniques devised to indirectly retrieve topological information, by correlating the balance of the flows as the water demand varies over time
Portable Multi-sensor System for Digital Processing of Electrocardiographic Signals
No full textIn the field of medicine and wearable health devices, the need of monitoring the cardiac activity continuously represents a challenge. Electrocardiography is the analysis of cardiac electrical activity, that can be conducted in a clinic with the electrocardiograph. This represents an accurate way to do the analysis, but it is necessary for the patient to go to the clinic, and that can limit the possibility of detecting random cardiac pathological events. In fact, some cardiac pathologies can manifest themselves as non-permanent variations in one or more electrocardiographic leads. As a result, the patient may complain of the symptom but come to the clinic and show a healthy ECG. A portable cardiac monitoring system have to be able to take over on every difference in the acquired cardiac signal from the reference labelled as healthy. Thus, it is essential to ensure that the patient, during the monitoring activity, can carry out daily activities. The aim of this paper is to present a 12-lead ECG portable system based on TI ADS1298. It is an 8 channel, 24 bit analog-to-digital sigma-delta converter. Two ADS1298 connected in daisy-chain mode have been integrated on a single board, in order to be able to acquire from 12 channels (i.e. all 12 cardiac leads). The board communicates with an STM32H743ZI microcontroller. In order to pick up the motion signal, a 6-axis small IMU was integrated in the system, LSM6DSV16X from STMicroelectronics. A threshold mechanism was therefore implemented to allow the acquisition of the ECG signal based on the signal read by the accelerometer
Synchronized Vibration Data Acquisition for Seismocardiography
No full textSeismocardiography (SCG) is a non-invasive technique that detects the heart’s vibrations to evaluate its mechanical activity. This research presents the design of a SCG device that utilizes a sensor fusion algorithm accurate detection of heart vibrations. The hardware comprises a main board with a high-performance microcontroller and multiple satellite boards, each equipped with MEMS sensors. The system’s signal analysis involves a correlation-based sensor fusion algorithm for noise reduction. Preliminary results demonstrate the system’s efficacy in reducing noise and cleaning the acquired signal. The study concludes with the benefits of the described SCG system when compared to single-sensor setups. As a future step we will work on systems with an increased number of sensors for simultaneous and precise detection of various heart sounds
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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