Browsing by Subject "noise"

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  • Knuutila, Antti (Helsingfors universitet, 2012)
    Brains are capable of processing information with remarkable efficiency under constraints set by the limited supply of physical resources such as the amount of space and the availability of metabolic energy. Natural selection has optimised the structure and function of brain networks using simple design rules similar to those found in man-made electronic and information systems. This study presents findings concerning a number of general principles of brain design governing the evolution and organisation of neural information processing. The rule of minimising wiring in neuronal networks is one such principle operating on multiple levels of brain organisation. Both individual components and larger brain architectural units are seen to feature characteristics of near-optimal wiring. Miniaturisation of neuronal components conserves space but raises problems about noise in signalling. Small-world organisation of anatomical and functional networks is widely employed in the brain, contributing to high global efficiency at low cost. Metabolic costs severely constrain signal traffic in the human brain, necessitating the use of energy-efficient sparse neural representations. Extensive evidence is presented of anatomical and physiological optimisations facilitating efficient information processing in brain networks. Limitations of current experimental techniques are discussed, with a view on possible future avenues of research.
  • Pareyon, Gabriel (2015)
    This essay is simultaneously registered in social and socio-acoustic anthropology focused on a Latin American context, adopting concepts from sociolinguistics and semiotics to formulate the hypothesis that, in urban postmodernity, when the social tissue is broken down by the violence of the structure of a concentrated power, the subjugated groups and individuals replicate violence in the form of noise. As part of this game of forces, some “social lifestyles” are created, fostered by a dynamic of flows between human groups with different behaviors, and nevertheless with negotiation spheres, in the field and the habitus of social theory (adapted from Attali and Bourdieu). It is in these areas of power and negotiation where noise plays a crucial role in the social dynamics contained in "socio-acoustic bands", transient processes of sound signs, eloquent about a specific community. Finally, it is explained how these dynamics can configure coexistence modalities, that is, socio-acoustic damping systems between different social groups. The work is also a detailed critique against conventional "solutions" to the noises of postmodern society, with special attention to the Mexican case.
  • Marsh, John E.; Ljung, Robert; Nostl, Anatole; Threadgold, Emma; Campbell, Tom A. (2015)
    A dynamic interplay is known to exist between auditory processing and human cognition. For example, prior investigations of speech-in-noise have revealed there is more to learning than just listening: Even if all words within a spoken list are correctly heard in noise, later memory for those words is typically impoverished. These investigations supported a view that there is a "gap" between the intelligibility of speech and memory for that speech. Here, the notion was that this gap between speech intelligibility and memorability is a function of the extent to which the spoken message seizes limited immediate memory resources (e.g., Kiellberg et al., 2008). Accordingly, the more difficult the processing of the spoken message, the less resources are available for elaboration, storage, and recall of that spoken material. However, it was not previously known how increasing that difficulty affected the memory processing of semantically rich spoken material. This investigation showed that noise impairs higher levels of cognitive analysis. A variant of the Deese-Roediger-McDermott procedure that encourages semantic elaborative processes was deployed. On each trial, participants listened to a 36-item list comprising 12 words blocked by each of 3 different themes. Each of those 12 words (e.g., bed, tired, snore...) was associated with a "critical" lure theme word that was not presented (e.g., sleep). Word lists were either presented without noise or at a signal-to-noise ratio of 5 decibels upon an A-weighting. Noise reduced false recall of the critical words, and decreased the semantic clustering of recall. Theoretical and practical implications are discussed.
  • Hoegaerts, Josephine; Kilpiö, Kaarina (2019)
    Sound ‘does’ things to places, to people and to time: it can affect change. This collection focuses specifically on the role sound has played as an agent of modernity. How were sound and music used as the material of modernization, how did they help create group identities, how were they mobilized in asserting power? In order to study this active quality of sound and music in the formation of the modern world, the contributors to this collection propose an interdisciplinary approach, including methods from sound studies and cultural musicology, and data from archives as well as record collections and catalogues.
  • Lehtola, Ville; Hyyti, Heikki; Keränen, Pekka; Kostamovaara, Juha (Copernicus Publications, 2019)
    The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
    Single photon lidars (in solid state form) offer several benefits over pulsed lidars, such as independence of micro-mechanical moving parts or rotating joints, lower power consumption, faster acquisition rate, and reduced size. When mass produced, they will be cheaper and smaller and thus very attractive for mobile laser scanning applications. However, as these lidars operate by receiving single photons, they are very susceptible to background illumination such as sunlight. In other words, the observations contain a significant amount of noise, or to be specific, outliers. This causes trouble for measurements done in motion, as the sampling rate (i.e. the measurement frequency) should be low and high at the same time. It should be low enough so that target detection is robust, meaning that the targets can be distinguished from the single-photon avalanche diode (SPAD) triggings caused by the background photons. On the other hand, the sampling rate should be high enough to allow for measurements to be done from motion. Quick sampling reduces the probability that a sample gathered during motion would contain data from more than a single target at a specific range. Here, we study the exploitation of spatial correlations that exist between the observations as a mean to overcome this sampling rate paradox. We propose computational methods for short and long range. Our results indicate that the spatial correlations do indeed allow for faster and more robust sampling of measurements, which makes single photon lidars more attractive in (daylight) mobile laser scanning.
  • Kellomäki, Seppo; Haapanen, Antti; Salonen, Hellevi (Suomen metsätieteellinen seura, 1976)