1,720,970 research outputs found
Development of SMEs in Bangladesh : lessons from the German Experience
No full textResearchers: M. A. Baqui Kahlily, Mohammed Jamal, Uddin, Muhammad Shariat Ullah, Mohammad Tare
An analysis of the role of stakeholders in TVET and apprenticeship in Bangladesh
No full textresearch team: Muhammad Shariat Ullah, PhD, professor and chariman Department of Organization Strategy and Leadership, University of Dhaka - Mohammad Abdul Jabber, associate professor, Department of Management, University Dhak
Micromagnetic tests of techniques for reducing pole tip remanence of high density perpendicular write heads.
No full textUniversity of Minnesota Ph.D. dissertation. September 2010. Major: Electrical Engineering. Advisor: Randall H. Victora. 1 computer file (PDF); xiii, 134 pages. Ill. (some col.)A multi-scale fast Fourier transform (FFT) based micromagnetic model has been developed to simulate erase after write (EAW) for a 2.4 T FeCo solid pole writer. The simulated remnant state of the writer shows vortices at the pole tip, break and paddle regions that qualitatively matches an experimental MFM image. Dynamic responses show that EAW worsens with a longer breakpoint. Sensitivity of EAW with breakpoint is in good agreement with the experimental data. Modeling suggests that cross track anisotropy reduces EAW risks; however, perpendicular anisotropy is found to be detrimental to EAW. Simulations show that EAW risks are substantially reduced when a uni-polar demagnetization pulse of polarity opposite to that of the last write is applied to the writer.
Using the model, the response functions of uni-polar demagnetization pulses have been modeled for reducing EAW events. Simulations show that the value of the initial field created by the demagnetization current is the most effective parameter in reducing pole tip remanence. To avoid driving the head in the opposite direction with the demagnetization pulse, it is important to ramp down quickly with a time constant of about 500 psec. In-plane exchange is found to affect EAW quite significantly; just 25% lower exchange reduces EAW fields by 30%. Modeling shows that introduction of antiferromagnetic coupling in the write pole reduces EAW significantly. Modeling also suggests that non-magnetic holes with in plane dimensions of 35 nm in the middle of the breakpoint region reduce EAW by ~35%. The underlying mechanism to reduce EAW is to make vortex formation in the pole tip energetically inexpensive.
Micromagnetics is used to design an unshielded perpendicular writer for an areal density of 1 Tb/in 2 . The head consists of a probe-type tip protruding from a collar. The tip has saturation magnetization ( M S ) of 24 kG while the collar has lower M S . The magnitude and orientation of anisotropy field ( H k ) in the tip is varied to obtain the best recording performance. The combination of high anisotropy write tip with low M S collar is shown to produce effective write fields in excess of 19 kOe and less than 20% track erasure for 10 7 passes. Introduction of in-plane anisotropy within the pole tip reduces head remanence sufficiently that on-track erasure exceeds a benchmark of 10 8 passes. The damping constant in the Landau-Lifshitz-Gilbert equation is varied to improve the frequency response. With damping constant equal to 1.0, simulations show that the head is capable of switching in approximately 0.15 ns.Patwari, Mohammed Shariat Ullah. (2010). Micromagnetic tests of techniques for reducing pole tip remanence of high density perpendicular write heads.. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/99054
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
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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