335 research outputs found
Application of sound source separation methods to advanced spatial audio systems
This thesis is related to the field of Sound Source Separation (SSS). It addresses the development
and evaluation of these techniques for their application in the resynthesis of high-realism sound scenes by
means of Wave Field Synthesis (WFS). Because the vast majority of audio recordings are preserved in twochannel
stereo format, special up-converters are required to use advanced spatial audio reproduction formats,
such as WFS. This is due to the fact that WFS needs the original source signals to be available, in order to
accurately synthesize the acoustic field inside an extended listening area. Thus, an object-based mixing is
required.
Source separation problems in digital signal processing are those in which several signals have been mixed
together and the objective is to find out what the original signals were. Therefore, SSS algorithms can be applied
to existing two-channel mixtures to extract the different objects that compose the stereo scene. Unfortunately,
most stereo mixtures are underdetermined, i.e., there are more sound sources than audio channels. This
condition makes the SSS problem especially difficult and stronger assumptions have to be taken, often related to
the sparsity of the sources under some signal transformation.
This thesis is focused on the application of SSS techniques to the spatial sound reproduction field. As a result,
its contributions can be categorized within these two areas. First, two underdetermined SSS methods are
proposed to deal efficiently with the separation of stereo sound mixtures. These techniques are based on a
multi-level thresholding segmentation approach, which enables to perform a fast and unsupervised separation of
sound sources in the time-frequency domain. Although both techniques rely on the same clustering type, the
features considered by each of them are related to different localization cues that enable to perform separation
of either instantaneous or real mixtures.Additionally, two post-processing techniques aimed at
improving the isolation of the separated sources are proposed. The performance achieved by
several SSS methods in the resynthesis of WFS sound scenes is afterwards evaluated by means of
listening tests, paying special attention to the change observed in the perceived spatial attributes.
Although the estimated sources are distorted versions of the original ones, the masking effects
involved in their spatial remixing make artifacts less perceptible, which improves the overall
assessed quality. Finally, some novel developments related to the application of time-frequency
processing to source localization and enhanced sound reproduction are presented.Cobos Serrano, M. (2009). Application of sound source separation methods to advanced spatial audio systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8969Palanci
Perception of Reverberation in Domestic and Automotive Environments
nrpages: 227status: publishe
Terahertz Communications and Sensing for 6G and Beyond: A Comprehensive View
The next-generation wireless technologies, commonly referred to as the sixth
generation (6G), are envisioned to support extreme communications capacity and
in particular disruption in the network sensing capabilities. The terahertz
(THz) band is one potential enabler for those due to the enormous unused
frequency bands and the high spatial resolution enabled by both short
wavelengths and bandwidths. Different from earlier surveys, this paper presents
a comprehensive treatment and technology survey on THz communications and
sensing in terms of the advantages, applications, propagation characterization,
channel modeling, measurement campaigns, antennas, transceiver devices,
beamforming, networking, the integration of communications and sensing, and
experimental testbeds. Starting from the motivation and use cases, we survey
the development and historical perspective of THz communications and sensing
with the anticipated 6G requirements. We explore the radio propagation, channel
modeling, and measurements for THz band. The transceiver requirements,
architectures, technological challenges, and approaches together with means to
compensate for the high propagation losses by appropriate antenna and
beamforming solutions. We survey also several system technologies required by
or beneficial for THz systems. The synergistic design of sensing and
communications is explored with depth. Practical trials, demonstrations, and
experiments are also summarized. The paper gives a holistic view of the current
state of the art and highlights the issues and challenges that are open for
further research towards 6G.Comment: 55 pages, 10 figures, 8 tables, submitted to IEEE Communications
Surveys & Tutorial
Contextual Beamforming: Exploiting Location and AI for Enhanced Wireless Telecommunication Performance
The pervasive nature of wireless telecommunication has made it the foundation
for mainstream technologies like automation, smart vehicles, virtual reality,
and unmanned aerial vehicles. As these technologies experience widespread
adoption in our daily lives, ensuring the reliable performance of cellular
networks in mobile scenarios has become a paramount challenge. Beamforming, an
integral component of modern mobile networks, enables spatial selectivity and
improves network quality. However, many beamforming techniques are iterative,
introducing unwanted latency to the system. In recent times, there has been a
growing interest in leveraging mobile users' location information to expedite
beamforming processes. This paper explores the concept of contextual
beamforming, discussing its advantages, disadvantages and implications.
Notably, the study presents an impressive 53% improvement in signal-to-noise
ratio (SNR) by implementing the adaptive beamforming (MRT) algorithm compared
to scenarios without beamforming. It further elucidates how MRT contributes to
contextual beamforming. The importance of localization in implementing
contextual beamforming is also examined. Additionally, the paper delves into
the use of artificial intelligence schemes, including machine learning and deep
learning, in implementing contextual beamforming techniques that leverage user
location information. Based on the comprehensive review, the results suggest
that the combination of MRT and Zero forcing (ZF) techniques, alongside deep
neural networks (DNN) employing Bayesian Optimization (BO), represents the most
promising approach for contextual beamforming. Furthermore, the study discusses
the future potential of programmable switches, such as Tofino, in enabling
location-aware beamforming
Recent Developments in Smart Healthcare
Medicine is undergoing a sector-wide transformation thanks to the advances in computing and networking technologies. Healthcare is changing from reactive and hospital-centered to preventive and personalized, from disease focused to well-being centered. In essence, the healthcare systems, as well as fundamental medicine research, are becoming smarter. We anticipate significant improvements in areas ranging from molecular genomics and proteomics to decision support for healthcare professionals through big data analytics, to support behavior changes through technology-enabled self-management, and social and motivational support. Furthermore, with smart technologies, healthcare delivery could also be made more efficient, higher quality, and lower cost. In this special issue, we received a total 45 submissions and accepted 19 outstanding papers that roughly span across several interesting topics on smart healthcare, including public health, health information technology (Health IT), and smart medicine
A Comprehensive Model and Modulation of Cellular Signaling Involved in Early Mammary Development and Aggressive Cancer Using a Novel Recombinant Protein of the G3 Domain of Laminin-5
The mammary gland is a unique and specialized epidermal organ; mammary organogenesis begins in the embryo but is not fully complete until puberty. As such, formation of the mammary gland depends on temporally and spatially regulated developmental steps that require coordination of multiple biological and cell signaling processes; many of which have parallels with cancer development. Research describing the events that occur between birth and puberty is lacking and little is known about human breast development of youth. Since mammary gland development requires a coordinated balance between cell growth, proliferation, and apoptosis, it is critical to understand which signaling pathways are utilized to relay developmental signals, and how these pathways and their targets interact and cooperate with age. Additionally, interactions between integrin molecules and their laminin ligands, especially Laminin-5 (Ln-5; also known as Laminin-332), regulate multiple facets of both embryonic development and tumor growth, invasion, and metastasis. α6β4 integrin serves as a marker to detect distant metastases in the early stages of specific malignancies and β4 integrin overexpression has been found in basal-like breast cancers, correlating with aggressiveness to institute a prognostic β4 signature that increases with tumor grade. The mechanism α6β4 integrin utilizes to modulate oncogenic signaling through association with Ln-5 molecules in the ECM is the basis for the recombinant protein (rG3, the third of five G domains of Ln-5) produced for the work reported in this dissertation. Here, it is shown there are specific transcriptional differences and a unique interaction of a gene set over time that contributes to postnatal mammary gland development, and this model clearly shares similarities and signaling pathways with oncogenic development. Especially important are pathways of the adaptive and innate immunities, ECM remodeling and integrin interactions, and extrinsic and intrinsic TP53-mediated apoptosis, greater understanding of which could lead to early detection of potential tumorigenic growth and identification of potential treatment avenues. Presented is a comprehensive model of early mammary development along with several panels of biomarkers that possess a role in normal mammary development, are involved in aggressive cancers, and are affected by apoptosis induced by rG3 treatment. rG3 has proven to be a valuable tool to study apoptotic pathways and the crosstalk among those pathways
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