37 resultados para VOICE INSTABILITIES
Resumo:
User-generated content (UGC) is attracting a great deal of interest - some of it effective, some misguided. This article reviews the marketing-related factors that gave rise to UGC, tracing the relevant development of market orientation, social interaction, word of mouth, brand relationships, consumer creativity, co-creation, and customization, largely through the pages of the Journal of Advertising Research over the last 40 (or so) of its 50 years. The authors then discuss the characteristic features of UGC and how they differ from (and are similar to) these concepts. The insights thus gained will help practitioners and researchers understand what UGC is (and is not) and how it should (and should not) be used.
Resumo:
This article compares the results obtained from using two different methodological approaches to elicit teachers’ views on their professional role, the key challenges and their aspirations for the future. One approach used a postal/online questionnaire, while the other used telephone interviews, posing a selection of the same questions. The research was carried out on two statistically comparable samples of teachers in England in spring 2004. Significant differences in responses were observed which seem to be attributable to the methods employed. In particular, more ‘definite’ responses were obtained in the interviews than in response to the questionnaire. This article reviews the comparative outcomes in the context of existing research and explores why the separate methods may have produced significantly different responses to the same questions.
Resumo:
Data assimilation algorithms are a crucial part of operational systems in numerical weather prediction, hydrology and climate science, but are also important for dynamical reconstruction in medical applications and quality control for manufacturing processes. Usually, a variety of diverse measurement data are employed to determine the state of the atmosphere or to a wider system including land and oceans. Modern data assimilation systems use more and more remote sensing data, in particular radiances measured by satellites, radar data and integrated water vapor measurements via GPS/GNSS signals. The inversion of some of these measurements are ill-posed in the classical sense, i.e. the inverse of the operator H which maps the state onto the data is unbounded. In this case, the use of such data can lead to significant instabilities of data assimilation algorithms. The goal of this work is to provide a rigorous mathematical analysis of the instability of well-known data assimilation methods. Here, we will restrict our attention to particular linear systems, in which the instability can be explicitly analyzed. We investigate the three-dimensional variational assimilation and four-dimensional variational assimilation. A theory for the instability is developed using the classical theory of ill-posed problems in a Banach space framework. Further, we demonstrate by numerical examples that instabilities can and will occur, including an example from dynamic magnetic tomography.
Resumo:
A weak instability mode, associated with phase-locked counterpropagating coastal Kelvin waves in horizontal anticyclonic shear, is found in the semigeostrophic (SG) equations for stratified flow in a channel. This SG instability mode approximates a similar mode found in the Euler equations in the limit in which particle-trajectory slopes are much smaller than f/N, where f is the Coriolis frequency and N > f the buoyancy frequency. Though weak under normal parameter conditions, this instability mode is of theoretical interest because its existence accounts for the failure of an Arnol’d-type stability theorem for the SG equations. In the opposite limit, in which the particle motion is purely vertical, the Euler equations allow only buoyancy oscillations with no horizontal coupling. The SG equations, on the other hand, allow a physically spurious coastal “mirage wave,” so called because its velocity field vanishes despite a nonvanishing disturbance pressure field. Counterpropagating pairs of these waves can phase-lock to form a spurious “mirage-wave instability.” Closer examination shows that the mirage wave arises from failure of the SG approximations to be self-consistent for trajectory slopes f/N.
Resumo:
A novel method is presented for obtaining rigorous upper bounds on the finite-amplitude growth of instabilities to parallel shear flows on the beta-plane. The method relies on the existence of finite-amplitude Liapunov (normed) stability theorems, due to Arnol'd, which are nonlinear generalizations of the classical stability theorems of Rayleigh and Fjørtoft. Briefly, the idea is to use the finite-amplitude stability theorems to constrain the evolution of unstable flows in terms of their proximity to a stable flow. Two classes of general bounds are derived, and various examples are considered. It is also shown that, for a certain kind of forced-dissipative problem with dissipation proportional to vorticity, the finite-amplitude stability theorems (which were originally derived for inviscid, unforced flow) remain valid (though they are no longer strictly Liapunov); the saturation bounds therefore continue to hold under these conditions.
Resumo:
Nonlinear stability theorems are presented for axisymmetric vortices under the restriction that the disturbance is independent of either the azimuthal or the axial coordinate. These stability theorems are then used, in both cases, to derive rigorous upper bounds on the saturation amplitudes of instabilities. Explicit examples of such bounds are worked out for some canonical profiles. The results establish a minimum order for the dependence of saturation amplitude on supercriticality, and are thereby suggestive as to the nature of the bifurcation at the stability threshold.
Resumo:
This article analyses how listening is used to develop performances in Alecky Blythe’s verbatim theatre. Listening includes Blythe’s use of recorded oral interviews for devising performances, and also the actors’ creation of performance by precisely imitating an interviewee’s voice. The article focuses on listening, speaking and embodiment in London Road, Blythe’s recent musical play at London’s National Theatre, which adopted and modified theatre strategies used in her other plays, especially The Girlfriend Experience and Do We look Like Refugees. The article draws on interviews with performers and with Blythe herself, in its critical analysis of how voice legitimates claims to authenticity in performance. The work on Blythe is contextualised by brief comparative analyses. One is Clio Barnard’s film The Arbor, a ‘quasi-documentary’ on the playwright, Andrea Dunbar which makes use of an oral script to which the actors lip-sync. The other comparator is the Wooster Group’s Poor Theater, which attempts to recreate Grotowski's Akropolis via vocal impersonation. The article argues that voice in London Road both claims and defers authenticity and authority, inasmuch as voice signifies presence and embodied identity but the reworking of speech into song signals the absence of the real. The translation of voice into written surtitles works similarly in Do We Look Like Refugees. Blythe’s theatre, Barnard’s film and The Wooster Group’s performances are a useful framework for addressing questions of voice and identity, and authenticity and replication in documentary theatre. The article concludes by placing Blythe’s oral texts amid current debates around theatre’s textual practices.
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This paper is an attempt to explore the challenges of defining intangible heritage and ‘community’ in England. It uses as its case study the Museum of English Rural Life, University of Reading: an urban museum with a rural theme. The paper examines current theoretical discourse around the concept of the ‘first voice’ and debate about the role of museums in the preservation of intangible heritage. It then examines the relevance of these concepts to the identification of ‘rural’ intangible heritage stake holders in England. In this way, it shows the potential for concepts of intangible heritage to influence national museums. However, by applying theory and practice which is designed to support work with well-defined ‘originating communities’ to a national museum, it also highlights the challenges of initiating community engagement in a multicultural society.
Resumo:
Trade unions provide a voice in the way firms are run, an input into reward systems and increased security of employment. But these vary with national context. Using transnational survey evidence, this article explores the relative impact of setting, and of unions and collective bargaining, on these issues. It is found that, irrespective of context, organizations are significantly more likely to make use of compulsory redundancies in the absence of unions and collective bargaining. However, in other areas, the impact of unions appeared less pronounced than that of the wider context. The article explores the reasons behind this, and the broader policy implications thereof.
Resumo:
Adults diagnosed with autism spectrum disorder (ASD) show a reduced sensitivity (degree of selective response) to social stimuli such as human voices. In order to determine whether this reduced sensitivity is a consequence of years of poor social interaction and communication or is present prior to significant experience, we used functional MRI to examine cortical sensitivity to auditory stimuli in infants at high familial risk for later emerging ASD (HR group, N = 15), and compared this to infants with no family history of ASD (LR group, N = 18). The infants (aged between 4 and 7 months) were presented with voice and environmental sounds while asleep in the scanner and their behaviour was also examined in the context of observed parent-infant interaction. Whereas LR infants showed early specialisation for human voice processing in right temporal and medial frontal regions, the HR infants did not. Similarly, LR infants showed stronger sensitivity than HR infants to sad vocalisations in the right fusiform gyrus and left hippocampus. Also, in the HR group only, there was an association between each infant's degree of engagement during social interaction and the degree of voice sensitivity in key cortical regions. These results suggest that at least some infants at high-risk for ASD have atypical neural responses to human voice with and without emotional valence. Further exploration of the relationship between behaviour during social interaction and voice processing may help better understand the mechanisms that lead to different outcomes in at risk populations.