1,720,968 research outputs found
Simulation of UWSNs performance evaluation
No full textAn extremely influential phenomenon in Underwater Sensor Networks shallow areas is the multipath effect. The transmission in underwater is being applied in depth areas up to 200 m. The receiving nodes receive the signal both from the direct path as well as from the other paths formed as result of the sea surface and bottom reflections. Losses from the surface reflections will increase if the surface roughness increases or, in other words, if the wind speed blowing in the surface increases. On the other hand, losses introduced from the bottom reflections will depend from the material composition. The total delay increases for more reflections as the signal that propagates from a longer path takes more time to reach the receiver when compared to the signal from the direct path. If we want to estimate the communication ability of acoustic channel, we need to consider the different materials that build the bottom of ocean and the reflection and dispersion of the signal during transmission in such links. © 2020, World Academy of Research in Science and Engineering. All rights reserved
Patients Behaviour Monitoring Inside a Hospital Garden: Comparison Between RADAR and GPS Solutions
No full textMonitoring the behaviors of inpatients with reduced cognitive abilities within an area of a hospital can provide important information on how patients live in that space and which part is of most interest. In this paper two different techniques are applied to perform this monitoring in an outdoor space; the former is based on the GPS positioning and timing, and the subjects must wear a suitable device, while the latter is based on a non-contact radar technology. Radar sensors are in fact nowadays very powerful even for medical applications and can be used to monitor patients within environments. In this work, the behaviors monitoring of the people inside the garden of a retirement house is considered. The two different techniques are used for tracking the subjects and the results are compared
Underwater wireless sensor networks: Estimation of acoustic channel in shallow water
Get PDFUnderwater sensor networks (UWSN) include a large number of devices and sensors which are positioned in a specific area to carry out monitoring in cooperation with each other as well as data collection. In this paper it has been studied and simulated the performance of an extremely important parameter for communication in UWSN such as the acoustic channel capacity as function of water temperature and salinity arise. The performance's knowledge on acoustic channel may be improved with a deep study of its dependence by season, weather conditions or environmental parameters variation. If an accurate estimation of the acoustic communication capacity utilization for a given area is required, we must consider also the bottom materials of this area. The simulation results presented in this study through an improved algorithm, will help to understand better the underwater acoustic channel performance as a function of all these factors. This is of particular importance for acoustic modems designing, in order to implement suitable functionalities able to adapt the data transmission capacity of the acoustic link to the structure of the oceanic bottom and its component material
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Performance evaluation of vibrational measurements through mmwave automotive radars
Get PDFThanks to the availability of a significant amount of inexpensive commercial Frequency Modulated Continuous Wave Radar sensors, designed primarily for the automotive domain, it is interesting to understand if they can be used in alternative applications. It is well known that with a radar system it is possible to identify the micro-Doppler feature of a target, to detect the nature of the target itself (what the target is) or how it is vibrating. In fact, thanks to their high transmission frequency, large bandwidth and very short chirp signals, radars designed for automotive applications are able to provide sub-millimeter resolution and a large detection bandwidth, to the point that it is here proposed to exploit them in the vibrational analysis of a target. The aim is to evaluate what information on the vibrations can be extracted, and what are the performance obtainable. In the present work, the use of a commercial Frequency Modulated Continuous Wave radar is described, and the performances achieved in terms of displacement and vibration frequency measurement of the target are compared with the measurement results obtained through a laser vibrometer, considered as the reference instrument. The attained experimental results show that the radar under test and the reference laser vibrometer achieve comparable outcomes, even in a cluttered scenario
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Global Positioning System measurements: Comparison of IoT wearable devices
No full textGlobal Positioning System (GPS) receivers can be commonly found onboard Internet of Things devices, including wearables such as smartwatches and smart wristbands, thanks to miniaturization and power consumption reduction currently achieved by industrial processes. In recent applications, GPS-enabled smartwatches have been used also to monitor outdoor mobility of impaired or ageing users in free-living conditions. This work compares the GPS measurements performed by three commercial smartwatches in several outdoor positions. The results show that the devices present different measurement precision, depending on the chosen propagation scenario
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