1,720,961 research outputs found
A novel experimental-based tool for the design of LoRa networks
No full textThe use of Long Range (LoRa) technology in Internet of Things (IoT) deployments is exponentially increasing, as it allows to form one-hop networks linking tiny nodes to one (or more) gateways and ensuring a low power consumption. In dense networks, predicting the number of supported nodes in relation to their position and the propagation environment is essential to ensure a reliable and stable communication and limit costs. In this paper, after comparing different path loss models based on a field measurement campaign of LoRa Received Signal Strength Indicator (RSSI) values within our University campus, we implement two main modifications to the LoRa Simulator tool, in order to improve its accuracy in the prediction of the number of sustainable nodes, according to the target Data Extraction Rate. By an improved path loss evaluation, and using three gateways, the number of nodes could increase theoretically from about 100 to about 6000. Future work includes the possibility to validate the accuracy of the tool, by designing a dense network operating in real conditions (i.e. large industrial plant, small/medium size city area) and testing its performances
A field-measurements-based LoRa network planning tool
Full text linkLong range (LoRa) transmission technology enables energy-constrained devices such as the tiny sensor systems used in internet-of-things applications that are distributed over wide areas while still being able to establish appropriate connectivity. This has resulted in the development of an exponentially increasing number of different solutions and services based on LoRa, be they dedicated to the long-term monitoring of distributed plants and infrastructures or to human-centred applications such as safety-oriented sensor systems for use in the workplace. In dense LoRa networks, predicting the number of supported nodes in relation to their position and the propagation environment is essential for ensuring reliable and stable communication and minimising costs. In this paper, after comparing different path loss models based on a field measurement campaign for LoRa received signal strength indicator values within a university campus, two main modifications of the LoRa simulator tool were implemented. These were aimed at improving the accuracy of the prediction of the number of sustainable nodes in relation to the target data extraction rate set. The simulations based on field measurements demonstrated that through an improved path loss evaluation and the use of three gateways, the number of nodes could be increased theoretically from around 100 to around 6,000
LoRa Evaluation in Mobility Conditions for a Connected Smart Shoe Measuring Physical Activity
No full textA strong and positive association between increased levels of physical activity, exercise participation and improved health in older adults emerges from research studies. It is consequently relevant to measure not only the amount of physical exercise performed during planned sessions, but also the level of activity all over the daytime. This paper presents a wearable solution that exploits properly instrumented shoes and a low power Long Range communication interface, to measure the user's activity levels in a minimally invasive way. The paper considers the features and limits of the Long Range transmission technology tested in mobility conditions, with a specific focus on the packet loss rate, to evaluate if they match with the requirements of a wearable solution designed to measure the subject's physical activity levels
Sensors Characterization for a Calibration-Free Connected Smart Insole for Healthy Ageing
No full textThe design of technological aids to assist older adults in their ageing process and to ensure proper attendance and care, despite the decreasing percentage of young people in the demographic profiles of many developed countries, requires the proper selection of sensing components, in order to come up with devices that can be easily used and integrated into everyday life. This paper addresses the metrological characterization of pressure sensors to be inserted into smart insoles aimed at monitoring the older adult’s physical activity levels. Two types of sensing elements are evaluated and a recommendation provided, based on the main requirement of designing a calibration-free insole: in this case, the pressure sensor should act as a switch, and the FSR 402 Short sensing element appears to be the proper solution to adopt
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
Variations on the Author
Full text link“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
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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