1,720,958 research outputs found
Design of remotely located and multi-loop vibration controllers using a sequential loop closing approach
Full text linkIn some applications, vibration control objectives may require reduction of levels at locations where control system components cannot be sited due to space or environmental considerations. Control actuators and error sensors for such a scenario will need to be placed at appropriate locations which are potentially remote from the points where ultimate attenuation is desired. The performance of the closed loop system, therefore, cannot be assessed simply by the measurement obtained at this local error sensor. The control design objective has to take into account the vibration levels at the remote locations as well. A design methodology was recently proposed that tackles such problems using a single-loop feedback control architecture. The work in this paper describes an extension of this control design procedure to enable the systematic design of multiple decentralised control loops. The approach is based upon sequential loop closing and conditions are provided that ensure that closed loop stability is maintained even in the event of failure in some control loops. The design procedure is illustrated through its application to a laboratory scale slab floor that replicates the problems associated with human induced vibration in large open-plan office buildings. The experimental results demonstrate the efficacy of the approach and significant suppression of the dominant low frequency modes in the floor is achieved using two independent acceleration feedback control loop
Experimental validation of a geometric method for the design of stable and broadband vibration controllers using a propeller blade test rig
No full textA systematic geometric design methodology to generate a stable controller for simultaneous local and remote attenuation that was previously proposed is experimentally validated on a structure. The local control path transfer function for this experimental system is non-minimum phase due to which the original broadband controller design would yield an unstable controller. Here a modified procedure for systems with local non- minimum phase dynamics is used to generate a stable controller. According to this method, reduction in vibration at local and remote points on a structure can be parameterised in terms of the available design freedom and a controller is realised in terms of the optimal selection of this using the minimum phase counterpart of the local control path transfer function. The modified method results in a controller that is both stable and stabilizing and which achieves the desired vibration attenuation at the local and remote points on the structure. An experimental facility that replicates the vibration transmission through the shaft of a propeller blade rig system is used to demonstrate the method. Vibration for excitation near the first bending mode frequency of the resonating part of this structure is attenuated at the non-resonating part of the system without deteriorating vibration at the resonating en
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
CROWDFUNDING-WAQF MELALUI PLATFORM WAKAF KITA UNTUK PROYEK INFRASTRUKTUR PENDIDIKAN
No full textCrowdfunding-Waqf merupakan pengumpulan dana wakaf dari masyarakat secara turun dana melalui teknologi, yaitu dikumpulkan pada platform Crowdfunding. Wakaf Kita di Kabupaten Jombang adalah salah satu lembaga yang menerapkan Crowdfunding-Waqf. Crowdfunding-Waqf yang dilakukan oleh lembaga Wakaf Kita berorientasi pada pendanaan proyek infrastruktur pendidikan. Tujuan dalam penelitian ini adalah untuk menganalisis strategi dan peran Crowdfunding-Waqf melalui platform Wakaf Kita untuk proyek infrastruktur pendidikan serta untu mengetahui pendapatan lembaga Wakaf Kita. Penelitian ini menggunakan pendekatan kualitatif dengan jenis penelitian deskriptif. Hasil penelitian menunjukan bahwa strategi Crowdfunding-Waqf melalui Platform Wakaf Kita untuk Proyek Infrastruktur Pendidikan lebih mudah, jangkauan syiar yang lebih luas, dan efisien. Peran Crowdfunding-Waqf terhadap Proyek Infrastruktur Pendidikan yaitu sebelum dilakukan Crowdfunding-Waqf Wakaf Kita, terdapat pelaku utama yaitu pencari dana atau fundraiser, donatur atau crowdfunder, dan penghubung di antara keduanya. Crowdfunding-Waqf terhadap Proyek Infrastruktur Pendidikan dengan langkah operasional mengunggah dan mengajukan usulan proyek, memilih proyek yang ingin mereka bantu pendanaannya yaitu proyek pendidikan, Wakif mentransfer/mengirim dana, dan Wakif dalam hal ini menerima jaminan berupa sertifkan atau tanda terima. Pendapatan lembaga Wakaf Kita melalui strategi Crowdfunding-Waqf berasal dari pengelolaan wakaf produktif, yaitu dengan memproduktifkan donasi tersebut
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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