1,720,963 research outputs found
Estimation of Maximum RF-EMF Exposure by Single-User MIMO mmWave 5G Systems
Full text linkThe assessment of maximum exposure levels generated by 5G base stations via the Maximum-Power Extrapolation (MPE) procedure defined in international standards is challenged by the technical traits of next-generation signals. Dynamic resource allocation to multiple users produces highly non-uniform signal frames in both frequency and time, complicating worst-case exposure evaluation. Furthermore, massive MIMO beamforming reduces the reliability of control channel–based measurements, motivating traffic-forcing techniques. The wide frequency span of 5G necessitates measurement protocols applicable to both FR1 and FR2 bands. In this paper, we compare conventional methods–namely, Channel Power (CP) and Zero Span (ZS)–against vector-based techniques like Vector Channel Power (VCP) and PDSCH Power (PP), based on the demodulation of the received signal. Unlike most studies focused on FR1, our measurements target a 5G millimeter-wave MIMO signal under realistic network conditions, including multi-user setups and diverse traffic-forcing scenarios. The results show that decoding-based procedures analyzing the PDSCH traffic channel reliably estimate maximum exposure, even when network operation deviates from ideal scenarios. These findings support integrating PDSCH-based methodologies into future revisions of standards such as IEC 62232
Preliminary Results of Maximum RF Power Measurement for 4G/5G Dynamic Spectrum Sharing Systems
No full textFacing Challenges in Zero-Span Measurements of 5G mm-Wave EMF Power in LoS and NLoS Propagation
Full text linkWe present a methodology for on-site zero-span (ZS) measurement of incident power generated by 5G base stations (BSs) that operate at millimeter-waves (mm-waves), analyzing the challenges offered by the new frequency band and nonline-of-sight (NLoS) propagation, which is the most common situation for mobile network users. We also investigate the impact of omnidirectional and directional measurement antennas. This is the first research on this topic available in scientific literature. Our results reveal that the measurement method designed for frequencies below 6 GHz in line-of-sight (LoS) conditions is also applicable in the mm-wave range. At the same time, in NLoS, mitigation strategies are suggested to measure signals accurately. That is, an omnidirectional antenna is recommended since a directional one requires an initial assessment to align the probe with the direction of the strongest signal. In addition, directional antennas under NLoS conditions do not guarantee that the power density coming from different directions due to reflections is measured entirely. This study holds significant importance for international standardization bodies focusing on establishing measurement methods to evaluate exposure originating from mobile network BSs
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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