1,354,793 research outputs found
Closed-loop stability analysis of a gantry crane with heavy chain and payload
No full textIn this paper, we analyze a systematically designed and easily tunable backstepping-based boundary control concept developed by Thull, Wild, and Kugi (2006) for a gantry crane with heavy chain and payload. The corresponding closed-loop system is formulated as an abstract evolution equation in an appropriate Hilbert space. Non-restrictive conditions for the controller coefficients are derived, under which the solutions are described by a C0-semigroup of contractions, and are asymp-totically stable. Moreover, by applying Huang's theorem we can finally even show that under these conditions the controller renders the closed-loop system exponen-tially stable
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
Iterative shaping of optical potentials for one-dimensional Bose-Einstein condensates
No full textThe ability to manipulate clouds of ultra-cold atoms is crucial for modern experiments on quantum many-body systems and quantum thermodynamics as well as future metrological applications of Bose-Einstein condensate. While optical manipulation offers almost arbitrary flexibility, the precise control of the resulting dipole potentials and the mitigation of unwanted disturbances is quite involved and only heuristic algorithms with rather slow convergence rates are available up to now. This paper thus suggests the application of iterative learning control (ILC) methods to generate fine-tuned effective potentials in the presence of uncertainties and external disturbances. Therefore, the given problem is reformulated to obtain a one-dimensional tracking problem by using a quasicontinuous input mapping which can be treated by established ILC methods. Finally, the performance of the proposed concept is illustrated in a simulation scenario
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
On the Passivity Based Impedance Control of Flexible Joint Robots
No full textIn this paper, a novel type of impedance controllers for
flexible joint robots is proposed. As a target impedance, a desired
stiffness and damping are considered without inertia shaping. For
this problem, two controllers of different complexity are proposed.
Both have a cascaded structure with an inner torque feedback loop
and an outer impedance controller.For the torque feedback, a physical
interpretation as a scaling of the motor inertia is given, which
allows to incorporate the torque feedback into a passivity-based
analysis. The outer impedance control law is then designed differently
for the two controllers. In the first approach, the stiffness and
damping terms and the gravity compensation term are designed
separately. This outer control loop uses only the motor position
and velocity, but no noncollocated feedback of the joint torques or
link side positions. In combination with the physical interpretation
of torque feedback, this allows us to give a proof of the asymptotic
stability of the closed-loop system based on the passivity properties
of the system. The second control law is a refinement of this
approach, in which the gravity compensation and the stiffness implementation
are designed in a combined way. Thereby, a desired
static stiffness relationship is obtained exactly. Additionally, some
extensions of the controller to viscoelastic joints and to Cartesian
impedance control are given. Finally, some experiments with the
German Aerospace Center (DLR) lightweight robots verify the developed
controllers and show the efficiency of the proposed control
approach
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
Get PDFThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
The Thursday Murder Club: Launching a megabrand author - a publishing case study
Get PDFIn 2020, the Christmas book charts in the UK made headlines: Barack Obama’s eagerly awaited autobiography, The Promised Land, was beaten to the top spot by The Thursday Murder Club by Richard Osman, a debut cosy crime novel set in a retirement village. Not only did Osman’s book beat the former US president’s expected bestseller, it also broke records, becoming the fastest-selling debut crime novel of all time. Although Osman has a certain level of fame in the UK from his TV appearances on shows such as Pointless, his celebrity status does not entirely explain the novel’s huge sales. This article tracks the acquisition, publication, and promotion journey of The Thursday Murder Club in order to understand the industry and cultural context of its success and to interrogate the role of celebrity in the creation of author brands. The findings suggest that the unexpected scale of the success of the book owed to a number of factors, including in-depth editing by the novel’s agent, editor, and author to tighten up the plot, an extensive and strategic promotional campaign, the pandemic (which drove interest in the book’s genre and themes), and the quality of the writing. We find that the book’s success was accentuated by Osman’s celebrity status rather than being entirely reliant on it. This research adds to the growing scholarship on celebrity authorship by means of an in-depth case study and provides insight into the processes behind publishing a ‘celebrity’ book and launching a megabrand author
Čustva strahu v pripovedih o kugi in sodobni pandemiji Covid-19
No full textNarratives about the plague and other pandemics essentially induce fear and predict death and hunger, triggering a variety of emotions among people, particularly anxiety. The paper discusses how the motifs of plague narratives – despite being ancient, traditional and old – resurface from the collective memory and the subconscious as people now have experiences comparable to those endured by humanity centuries ago. Although the COVID-19 pandemic that confronted the planet from 2019 to 2022 is not as deadly as the plague, it is still an ongoing existential threat. A discussion is also presented of the ways that old traditions and social constructs re-emerge in contemporary narratives and discourses about COVID-19, and how the atmosphere of fear affects the emotional and social lives of the people, along with their narratives, jokes, fake news, and the conspiracy theories that have been circulating online.Pripovedi o kugi in drugih pandemijah povzročajo strah in napovedujejo smrt in lakoto ter povzročajo vrsto čustev med ljudmi, predvsem nelagodje. V tem članku je analizirano, kako pripovedno izročilo o kugi, čeprav staro in preživeto, ponovno prihaja na dan v kolektivnem spominu in podzavesti, ko ljudje ponovno doživljajo podobne izkušnje, kot jih je izkusilo človeštvo pred stoletji. Čeprav pandemija Covid-19 – s katero se soočamo med leti 2019 in 2022 – ni tako smrtonosna kot kuga, jo vendar občutimo, kot stalno grožnjo. V članku je predstavljeno, kako stari tradicionalni družbeni konstrukti ponovno prihajajo na dan v sodobnih povedkah in pripovednih diskurzih o Covidu-19 in kako se občutje strahu odraža v družbenem življenju ljudi, kakor tudi v njihovih pripovedih, vicih, teorijah zarote in lažnih novicah, ki krožijo po spletu
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