1,720,955 research outputs found
Nonlinear modeling for audio and acoustic systems
No full textThe market for technology incorporating voice-based interfaces is experiencing rapid expansion. The main reason for this growth is people's desire to use devices without their hands. A diverse range of applications such as voice-controlled gadgets, systems that can recognize voices or speakers, hands-free communication devices, systems for talking in noisy places without needing to speak directly into a microphone, and tools to help people with hearing problems. Nevertheless, in most scenarios, these systems suffer from acoustic feedback and ambient noise, which significantly reduce their effectiveness. Because of this, the people who design speech processing systems are very interested in finding ways to eliminate echoes and reduce background noise. In telecommunications remote conference is used to facilitate hands-free communication between users in multi-source environments without a body-attached mic or a wired microphone. As a result, this advancement brings challenges, as interfering sounds may disrupt both the quality and comprehensibility of your target speech. In hands-free communication, a conversation typically occurs between speakers at the near-end and far-end points. The near-end microphone picks up the intended speech signal and two interfering signals: the echo from a loudspeaker recreating the far-end signal and background noise. This acoustic coupling between the loudspeaker and microphone can reduce speech clarity at the far-end due to the echo. These issues arise from linear or nonlinear processes hence requiring similar adaptive solutions. Designing adaptive filters for this purpose presents various challenges related to modeling the acoustic pathway. This investigation deals with these modeling concerns by recommending new adaptive algorithms that enhance robustness against interferences on audio processing systems. With this novel technique, conventional design approaches can be bypassed leading to more efficient and effective adaptive filters. In this thesis, we illustrate our framework by focusing on audio applications where we developed a type of Linear-in-parameter nonlinear adaptive filter that is suitable for nonlinear acoustic echo cancellation applications. We set: Develop a new nonlinear model for efficient online processing in real-time applications, focusing on LIP filters implemented as Functional Link Adaptive Filters (FLAF). It will explore a novel class of FLAF using transformed domain adaptive filters, particularly Frequency Domain Adaptive Filters (FDAF) and their Partitioned Block variant (PBFDAF). The research will design a new algorithm for Nonlinear Acoustic Echo Cancellation (NAEC), investigate various expansion methods for the Functional Expansion Block (FEB), conduct experiments using simulated and real audio data, compare performance and computational complexity of different adaptation algorithms. Introduces a new class of FLAFs based on nearest Kronecker product (NKP) decomposition. These filters are designed for nonlinear system identification, capable of handling unknown degrees of nonlinearity by updating the most influential coefficients. Recognizing that not all weights significantly contribute to the model, the approach leverages the low-rank nature of weight vectors to improve convergence and tracking performance compared to traditional FLAFs. The proposed NKP-based FLAFs also aim to enhance noise mitigation, particularly in nonlinear acoustic echo cancellation scenarios, offering improved adaptability and performance for practical nonlinear system identification applications. Introduces robust filtering architectures based on a novel framework using an Adaptive Exponential Functional Link (AEFL) that is preceding spline nonlinearity. This approach aims to improve performance consistency for various nonlinear systems. Simulations show that this method outperforms traditional FLAF models in tackling nonlinear distortions and enhancing signal quality. These filters have been extensively tested under different situations of acoustic audio applications ranging from nonlinear acoustic echo cancellation to reverberation detection. The results obtained using our method surpass those based on other techniques. The evaluation will encompass both computational efficiency and performance metrics. The discourse will conclude by presenting potential avenues for future research and development in this field
A New Class of Efficient Adaptive Filters for Online Nonlinear Modeling
Full text linkNonlinear models are known to provide excellent performance in real-world applications that often operate in nonideal conditions. However, such applications often require online processing to be performed with limited computational resources. To address this problem, we propose a new class of efficient nonlinear models for online applications. The proposed algorithms are based on linear-in-the-parameters (LIPs) nonlinear filters using functional link expansions. In order to make this class of functional link adaptive filters (FLAFs) efficient, we propose low-complexity expansions and frequency-domain adaptation of the parameters. Among this family of algorithms, we also define the partitioned-block frequency-domain FLAF (FD-FLAF), whose implementation is particularly suitable for online nonlinear modeling problems. We assess and compare FD-FLAFs with different expansions providing the best possible tradeoff between performance and computational complexity. Experimental results prove that the proposed algorithms can be considered as an efficient and effective solution for online applications, such as the acoustic echo cancellation, even in the presence of adverse nonlinear conditions and with limited availability of computational resources
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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