1,720,968 research outputs found
Machine Learning based Beamwidth Adaptation for mmWave Vehicular Communications
Get PDFThe incorporation of mmWave technology in vehicular networks has unlocked a realm of possibilities, propelling the advancement of autonomous vehicles,enhancing interconnectedness, and facilitating communication for intelligent transportation systems (ITS). Despite these strides in connectivity, challenges such as high path-loss have arisen, impacting existing beam management procedures. This work aims to address this issue by improving beam management techniques, specifically focusing on enhancing the service time between vehicles and base stations through adaptive mmWave beamwidth adjustments, accomplished using a Contextual Multi-Armed Bandit Algorithm. By leveraging various conditions to train the ML agent of the Contextual Multi-Armed Bandit Algorithm, it seeks to learn about vehicle mobility profiles and optimize the usage of differentantenna beamwidth settings to maximize seamless connection time. The extensive simulation results showcase the effectiveness of an adaptive beamwidth for mobility profiles, extending the connection time a vehicle experiences with a base station when compared to the existing strategies
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
Influences of wind and rain on radio wave propagation in foliated fixed wireless access at 5.8 GHz
Get PDFMovement of objects due to wind and rain in the vicinity of fixed wireless access introduces an adverse environment for high frequency radio wave propagation. In recent years, fixed wireless access deployed in suburban and rural areas are surrounded by large number of trees and hills. Although the transmitter and receiver of fixed wireless access remain in stationary positions, movement of trees in this foliated fixed wireless access would scatter, diffract and absorb the wireless signal causing signal fading. In this study, the focus was on the measurement temporal scale of the received signal strength in foliated fixed wireless access operating at the 5.8 GHz frequency of the Unlicensed National Information Infrastructure band. Based on the temporal scale of the measured received signal strength profiles of three different links comprising one line-of-sight and two non line-of-sight links, it was observed that line-of-sight link worked well even when it rained. The existence of trees in the vicinity of the transmission path caused signal deterioration where the received signal strength faded from 3 dB to 16 dB as the rain intensity increased. The wetness in the trees caused by rain had affected the received signal strength. To characterize the measured received signal strength, statistical characterization of the combined effects of several typical weather phenomena often experienced in a tropical region was also presented. The Rician distribution was used to characterize the fast fading effect due to both wind and rain. A smaller K-factor of the distribution represented more intense wind and rain conditions. Meanwhile, Lognormal distribution was found to be suitable in describing the slow fading characteristics in a foliated channel. The work reported in this thesis has determined the effects of wind and rain in the deployment of fixed wireless access in foliated channel to ensure optimized links be provided for end users
Millimeter Wave Outdoor Cellular Networks: Stochastic Geometry Channel Modeling And Performance Analysis
Get PDFFuture cellular networks will use millimeter wave (MMW) spectrum to enable extremely high data rates. Although this spectrum offers numerous significant performance improvements in wireless networks, MMW frequencies also have unique propagation characteristics and hardware constraints, which require revisiting the prior channel modeling and system design. In this thesis, we develop a geometry-based stochastic channel model to characterize the effect of the first-order reflection paths. We consider random locations, sizes and orientations of buildings and derive a closed-form expression for the power delay profile contributed by the first-order reflection paths. We show that wireless networks can benefit from buildings in the communication area, as the external building surfaces render reflection paths whose signal powers are comparable to that of the direct path. Dense base station (BS) deployments are required to overcome the signal losses due to blockages, which unfortunately introduce additional interference at the receiver. We propose a BS coordination scheme to improve the user performance in the dense MMW cellular networks. We derive expressions for the signal-to-interference and noise ratio (SINR) coverage probability and area spectral efficiency (ASE) by incorporating the peculiarity characteristics of MMW communications. Our results show a significant improvement in performance in terms of SINR coverage probability and ASE. In this thesis, we also investigate the uplink performance of the MMW cellular networks. We model the locations of users as of a Poisson cluster process and develop an analytical expression to evaluate the SINR coverage probability. We study the performances of a typical BS for two association strategies, i.e., the closest-selection (CS) and the strongest-selection (SS). Our results show that regarding SINR coverage probability, the SS strategy outperforms the CS strategy in the environment with dense blockages
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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