3,822 research outputs found
On the convex components of a set in
No full textWe prove a lower bound on the number of the convex components of a compact
set with non-empty interior in for all . Our result
generalizes and improves the inequalities previously obtained in M. Carozza, F.
Giannetti, F. Leonetti and A. Passarelli di Napoli, "Convex components", in
Communications in Contemporary Mathematics, Vol. 21, No. 06, 1850036 (2019) and
in M. La Civita and F. Leonetti, "Convex components of a set and the measure of
its boundary", Atti. Sem. Mat. Fis. Univ. Modena Reggio Emilia 56 (2008-2009)
71-78.Comment: 16 pages, 6 figure
ON THE LIPSCHITZ REGULARITY FOR MINIMA OF FUNCTIONALS DEPENDING ON x, u, AND ∇u UNDER THE BOUNDED SLOPE CONDITION
No full textWe prove the existence of a global Lipschitz minimizer of functionals of the form
I (u) =
\int
\Omega f(\nabla u(x)) + g(x, u(x)) dx, u \in \phi + W1,1
0 (\Omega ), assuming that \phi satisfies the bounded slope
condition (BSC). Our assumptions on the Lagrangian allow the function f to be strongly degenerate
Structural sensitivity of the finite-amplitude vortex shedding behind bluff bodies
No full textInthispaperwestudythestructuralsensitivityofthenonlinearperiodic oscillation arising in the wake of a circular cylinder for Re47. The sensibility of the periodic state to a spatially localised feedback from velocity to force is anal- ysed by performing a structural stability analysis of the problem. The sensitivity of the vortex shedding frequency is analysed by evaluating the adjoint eigenvectors of the Floquet transition operator. The product of the resulting neutral mode with the nonlinear periodic state is then used to localise the instability core. The results ob- tained with this new approach are then compared with those derived by Giannetti & Luchini [8]. An excellent agreement is found comparing the present results with the experimental data of Strykowski & Sreenivasan
WKBJ analysis in the periodic wake of a cylinder
No full textAbstractThe nature of the three-dimensional transition arising in the flow past a cylinder is investigated by applying the Lifschitz–Hameiri theory along special Lagrangian trajectories existing in its wake. Results show that the von Kármán street is unstable with regard to short-wavelength perturbations. The asymptotic analysis predicts the possible existence of both synchronous (as modes A and B) and asynchronous (as mode C) instabilities, each associated to specific Lagrangian orbits. The proposed study provides useful qualitative information on the origin of the different modes but no quantitative agreement between the growth rates predicted by the asymptotic analysis and by a global stability analysis is observed. The reasons for such mismatch are briefly discussed and possible improvements to the present analysis are suggested
Structural sensitivity of the finite-amplitude vortex shedding behind a circular cylinder
No full textIn this paper we study the structural sensitivity of the nonlinear periodic oscillation arising in the wake of a circular cylinder for Re47. The sensibility of the periodic state to a spatially localised feedback from velocity to force is analysed by performing a structural stability analysis of the problem. The sensitivity of the vortex shedding frequency is analysed by evaluating the adjoint eigenvectors of the Floquet transition operator. The product of the resulting neutral mode with the nonlinear periodic state is then used to localise the instability core. The results obtained with this new approach are then compared with those derived by Giannetti & Luchini [8]. An excellent agreement is found comparing the present results with the experimental data of Strykowski & Sreenivasan [7]. © 2009 Springer Science+Business Media B.V
A Twitter Case Study for Assessing Digital Sound
No full textAcademic and cultural heritage institutions around the world have made measurable strides in the development of digital sound archives oriented towards research and access, but their impact on scholarship and society has been little studied. Traditionally, impact has been measured by citations; yet these are problematic metrics for non-traditional outputs like sound recordings. Social media data provide a promising avenue of investigation for measuring scholarly as well as societal impact. Twitter in particular has been shown to provide a high number of references for cultural and research outputs in all disciplines. This study analyzes Twitter references pertaining to the collections of five digital sound archives: British Library Sounds, Europeana Sounds, the Internet Archive Audio Archive, PennSound and UbuWeb. Using text analysis methods to identify high frequency events and trends, and labeling them with a rubric designed for measuring the impact of digital heritage resources, this study provides preliminary insights on user values as they relate to digital sound collections. Despite the limitations of using social media data, the evidence gathered in this case study characterizes aspects of the use of digital sound collections, and may point to future priorities for the digital preservation of sound.Peer reviewe
A DH-Leavened Musicological Toolbox
No full textGraduate-level training in music research methodologies tends to ignore digital humanities work and overlook the use of digital tools created in support of new forms of reading. Training instead focuses on source material in the student’s area of interest. This material includes secondary and primary (archival) resources, as well as information resources, such as: monuments of music and critical editions; indexes; bibliographies and thematic catalogs; dictionaries and encyclopedias; digital libraries of scores or editions; and databases of period-specific newspapers or journals. Graduate students taking research methods courses already have a toolbox built from their experiences as musicians and students of music, including the ability to read and interpret music notation, to understand theoretical and analytical concepts in music, as well as a command of music history, including the canon of musical works.
Digital humanities has become a major area of academic endeavor at the “interface of technological development, epistemological change and methodological concerns." An important characteristic of digital humanities research has been its interdisciplinarity. We argue that graduate training in musicology needs to include coverage of methodologies applied by digital humanists in support of new forms of reading, not only to broaden the canon of research topics in musicology, but also to build common ground with researchers of other disciplines. We propose that librarians are well positioned to provide this expertise and training
Against the Grain: Reading for the Challenges of Collaborative DH Pedagogy
No full textThis article provides a critical review of the past five years of literature in digital humanities pedagogy and faculty-librarian collaboration, commingled with reflections on personal practice, which extend findings from the literature. Faculty-librarian partnerships in DH pedagogy reflect a rapidly evolving area of engagement calling for expertise in teaching, subject knowledge, scholarly communication, digital technologies, and DH research methodologies. Although there is a rapidly expanding body of literature on these partnerships, the challenges of the work tend to be minimized. This article expands upon commonly encountered difficulties, and it points to potential solutions and best practices.Peer reviewe
Review of Digital humanities in the library: challenges and opportunities for subject specialists
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