167 research outputs found
Square root-based multi-source early PSD estimation and recursive RETF update in reverberant environments by means of the orthogonal Procrustes problem
Multi-channel short-time Fourier transform (STFT) domain-based processing of
reverberant microphone signals commonly relies on power-spectral-density (PSD)
estimates of early source images, where early refers to reflections contained
within the same STFT frame. State-of-the-art approaches to multi-source early
PSD estimation, given an estimate of the associated relative early transfer
functions (RETFs), conventionally minimize the approximation error defined with
respect to the early correlation matrix, requiring non-negative inequality
constraints on the PSDs. Instead, we here propose to factorize the early
correlation matrix and minimize the approximation error defined with respect to
the early-correlation-matrix square root. The proposed minimization problem --
constituting a generalization of the so-called orthogonal Procrustes problem --
seeks a unitary matrix and the square roots of the early PSDs up to an
arbitrary complex argument, making non-negative inequality constraints
redundant. A solution is obtained iteratively, requiring one singular value
decomposition (SVD) per iteration. The estimated unitary matrix and early PSD
square roots further allow to recursively update the RETF estimate, which is
not inherently possible in the conventional approach. An estimate of the said
early-correlation-matrix square root itself is obtained by means of the
generalized eigenvalue decomposition (GEVD), where we further propose to
restore non-stationarities by desmoothing the generalized eigenvalues in order
to compensate for inevitable recursive averaging. Simulation results indicate
fast convergence of the proposed multi-source early PSD estimation approach in
only one iteration if initialized appropriately, and better performance as
compared to the conventional approach
Localization of a Virtual Wall by Means of Active Echolocation by Untrained Sighted Persons
The active sensing and perception of the environment by auditory means is
typically known as echolocation and it can be acquired by humans, who can
profit from it in the absence of vision. We investigated the ability of twentyone
untrained sighted participants to use echolocation with self-generated oral
clicks for aligning themselves within the horizontal plane towards a virtual wall,
emulated with an acoustic virtual reality system, at distances between 1 and 32
m, in the absence of background noise and reverberation. Participants were able
to detect the virtual wall on 61% of the trials, although with large di↵erences
across individuals and distances. The use of louder and shorter clicks led to an
increased performance, whereas the use of clicks with lower frequency content
allowed for the use of interaural time di↵erences to improve the accuracy of
reflection localization at very long distances. The distance of 2 m was the most
difficult to detect and localize, whereas the furthest distances of 16 and 32 m
were the easiest ones. Thus, echolocation may be used e↵ectively to identify
large distant environmental landmarks such as buildings
Localization Experiments with Reporting by Head Orientation: Statistical Framework and Case Study
This research focuses on sound localization experiments in which subjects report the position of an active sound source by turning toward it. A statistical framework for the analysis of the data is presented together with a case study from a large-scale listening experiment. The statistical framework is based on a model that is robust to the presence of front/back confusions and random errors. Closed-form natural estimators are derived, and one-sample and two-sample statistical tests are described. The framework is used to analyze the data of an auralized experiment undertaken by nearly nine hundred subjects. The objective was to explore localization performance in the horizontal plane in an informal setting and with little training, which are conditions that are similar to those typically encountered in consumer applications of binaural audio. Results show that responses had a rightward bias and that speech was harder to localize than percussion sounds, which are results consistent with the literature. Results also show that it was harder to localize sound in a simulated room with a high ceiling despite having a higher direct-to-reverberant ratio than other simulated rooms
Marketing (as) Rhetoric: paradigms, provocations, and perspectives
In this collection of short, invited essays on the topic of marketing (as) rhetoric we deal with a variety of issues that demonstrate the centrality of rhetoric and rhetorical considerations to the pursuit of marketing scholarship, research and practice. Stephen Brown examines the enduring rhetorical power of the 4Ps; Chris Hackley argues for the critical power of rhetorical orientations in marketing scholarship but cautions us on the need to work harder in conceptually connecting rhetorical theory and modern marketing frameworks; Shelby Hunt explains how rhetorical processes are incorporated in his inductive realist model of theory generation, using one of his most successful publications as an illustration; Charles Marsh demonstrates what Isocrates’ broad rhetorical project has to teach us about the importance of reputation cultivation in modern marketing; Nicholas O’Shaughnessy uses an analysis of Trump’s discourse to argue that political marketing as it is currently conceived is ill-equipped to engage effectively with the rhetorical force of Trump’s ‘unmarketing’; Barbara Phillips uses Vygotsky’s work on imagination to investigate the important of pleasure and play in advertising rhetoric; and finally, David Tonks, who in many ways started it all, reiterates the need for marketers to recognise the strength of the relationship between marketing and persuasion
Envelhecimento em um aço inoxidável AISI 304 contendo martensita induzida por deformação
Cost-effectiveness of 40-hour versus 100-hour vocational rehabilitation on work participation for workers on sick leave due to subacute or chronic musculoskeletal pain: study protocol for a randomized controlled trial
A global experiment on motivating social distancing during the COVID-19 pandemic
Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges
Patent cliff and strategic switch: exploring strategic design possibilities in the pharmaceutical industry
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