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Armstrong, J W (John William), VX32560
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/369047Surname: ARMSTRONG
Given Name(s) or Initials: J W (JOHN WILLIAM)
Military Service Number or Last Known Location: VX32560
Missing, Wounded and Prisoner of War Enquiry Card Index Number: 23755179089
Item: [2016.0049.01374] "Armstrong, J W (John William), VX32560
Spacecraft Doppler tracking: Noise budget and accuracy achievable in precision radio science observations
No full textReducing Doppler noise with multi-station tracking: The Cassini test case
No full textDoppler tracking of Solar System probes is used for spacecraft navigation, planetary geodesy, and tests of the theory of General Relativity. The spacecraft radial velocity is measured by observing the Doppler shift of a radio signal transmitted from an Earth station to the spacecraft and then re-transmitted back, while preserving phase coherence, to the same station (two-way link) or to a different station (three-way link). Specialized orbit determination software is then used to reconstruct the spacecraft trajectory and estimate planetary gravity field coefficients or relativistic parameters. The measurement noise is a crucial element for the accuracy of the final estimates, thus considerable effort has been devoted to improve the range rate accuracy by adopting higher frequency links to reduce the dispersive noise from interplanetary and ionospheric plasmas, and by calibrating the tropospheric path delays with microwave radiometers. While Ka-band radio links (32–34 GHz) allowed a successful suppression of plasma noise, reducing tropospheric noise and ground antenna mechanical noise has been more challenging. The Time-Delay Mechanical noise Cancellation (TDMC) technique is a promising method to reduce mechanical and tropospheric noises and to improve further the accuracy of Doppler measurements. The TDMC is a linear combination of simultaneous Doppler data from a main antenna providing the two-way link and a three-way antenna (generally smaller and stiffer). If the listen-only, three-way antenna is also located in a particularly dry site, the TDMC can considerably reduce both tropospheric and antenna mechanical noises, which are the leading disturbances in two-way Ka-band radio links. For an operational test of this method, we applied the TDMC to Doppler data at X-band (7.2–8.4 GHz) from the Cassini spacecraft acquired during the Saturn tour phase of the mission. Although X-band links are generally dominated by the highly-variable interplanetary plasma noise and are not suitable for the TDMC, we found that, when local noises are particularly large at the two-way antenna, this technique may still lead to up to a factor-of-three noise reduction (at 60-s integration time) with respect to the two-way link. The TDMC can maximize the data quality during unique events, mainly planetary or satellite flybys (such as those considered in the Europa Clipper and JUICE missions), where the scientific results could be severely hampered by adverse conditions at the tracking station
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
Armstrong, J. W.
No full textSee entry in Marion County volume 1, page 18: https://digital.archives.alabama.gov/digital/collection/voter/id/201
Armstrong, J. W.
No full textSee entry in Lawrence County volume 1, page 62: https://digital.archives.alabama.gov/digital/collection/voter/id/195
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
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