1,720,959 research outputs found
Analysis of GNSS data at the Moon for the LuGRE project
Full text linkThe Lunar GNSS Receiver Experiment (LuGRE) aims at testing positioning and navigation at the Moon by using Earth Global Navigation Satellite Systems. Within this framework, to support the scientific mission definition and to process on-ground the data that will be collected, a proper GNSS software receiver is needed, implementing advanced signal processing algorithms that enable it to work in the Moon scenario. This paper discusses the issues and potentialities, presenting the preliminary results of the simulation of the Moon environment, as far as the navigation tasks are concerned
A Sequence Matching Approach for GNSS-Based Orbit Determination Using Dynamic Time Warping
Full text linkAccurate navigation in deep space and lunar environments poses significant challenges due to limited GNSS signal availability and the need for robust state estimation that may take advantage of additional trajectory information. This paper investigates the application of sequence matching (SM) techniques to align a GNSS-based trajectory with a pre-designed aiding trajectory (AT), a crucial step in enhancing GNSS-based Position, Navigation, and Timing (PNT) solutions. We formulate the SM problem as a generalized constrained optimization problem and introduce, as a solution, a locally weighted Dynamic Time Warping (DTW) method tailored for GNSS state estimation fusion in challenging environments. The proposed approach is validated through comparisons with an exhaustive search benchmark and extended to assess different local cost functions---based on quasi-norm operators and angular distance---within both classical DTW and the locally weighted DTW framework. Performance analysis, conducted using realistic RF signal simulations for the cislunar environment and trajectories with error-affected sampling rate, demonstrates the effectiveness of the proposed method in handling signal degradation and time misalignment. These findings contribute to advancing autonomous space navigation, reducing reliance on ground-based tracking, and supporting future deep-space missions
LuNART-q: The LuGRE Quick Navigation Analysis and Reporting Tool
Full text linkThe Lunar GNSS Receiver Experiment (LuGRE) quick Navigation Analysis and Reporting Tool (LuNART-q) is a MATLAB-based platform developed by Politecnico di Torino for the Italian Space Agency (ASI) and in collaboration with NASA's SCAN program and Qascom S.r.l. Derived from a broader scientific framework for the LuGRE mission, it enables rapid visualization, validation and exploitation of GNSS data acquired in lunar and cislunar environments. LuNART-q automates telemetry parsing, analysis and post-processing of GNSS observables and I/Q batch analysis, navigation performance evaluation, and structured reporting. Twelve configurable "quick experiments", derived from LuGRE Science Definition Team Report objectives, produce experiment reports that can be consolidated into operation summary reports for immediate assessment. Visualization modules allow prompt analysis of signal availability, occultations, and receiver performance, while compliance with Ground System Working Group standards ensures interoperability. An open project based on LuNART-q will be released to allow the community to immediately explore LuGRE open data from the mission, fostering reproducibility, education, and collaborative research. By integrating predictive analysis, adaptive experiment execution, and reproducible reporting, LuNART-q provides an innovative framework that maximized the scientific return of the LuGRE mission and paves the way for companion software designed to support and advance scientific objectives in future missions
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
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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