535,781 research outputs found

    Statistical Properties of Single and Competing Non-Linear Fast-Slow Oscillators in Noise

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    Statistical properties offast-slow Ellias-Grossberg oscillators are studied in response to deterministic and noisy inputs. Oscillatory responses remain stable in noise due to the slow inhibitory variable, which establishes an adaptation level that centers the oscillatory responses of the fast excitatory variable to deterministic and noisy inputs. Competitive interactions between oscillators improve the stability in noise. Although individual oscillation amplitudes decrease with input amplitude, the average to'tal activity increases with input amplitude, thereby suggesting that oscillator output is evaluated by a slow process at downstream network sites.Air Force Office of Scientific Research (F49620-92-J-0225); Defense Advanced Research Projects Agency (ONR N00014-92-J-4015); National Science Foundation (IRI-90-24877); Office of Naval Researc

    Signal and noise in regime systems: a hypothesis on the predictability of the North Atlantic Oscillation

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    Studies conducted by the UK Met Office reported significant skill at predicting the winter NAO index with their seasonal prediction system. At the same time, a very low signal-to-noise ratio was observed, as measured using the `ratio of predictable components' (RPC) metric. We analyse both the skill and signal-to-noise ratio using a new statistical toy-model which assumes NAO predictability is driven by regime dynamics. It is shown that if the system is approximately bimodal in nature, with the model consistently underestimating the level of regime persistence each season, then both the high skill and high RPC value of the Met Office hindcasts can easily be reproduced. Underestimation of regime persistence could be attributable to any number of sources of model error, including imperfect regime structure or errors in the propagation of teleconnections. In particular, a high RPC value for a seasonal mean prediction may be expected even if the models internal level of noise is realistic.Comment: Published in the Quarterly Journal of the Royal Meteorological Society (2019

    A noise assessment and prediction system

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    A system has been designed to provide an assessment of noise levels that result from testing activities at Aberdeen Proving Ground, Md. The system receives meteorological data from surface stations and an upper air sounding system. The data from these systems are sent to a meteorological model, which provides forecasting conditions for up to three hours from the test time. The meteorological data are then used as input into an acoustic ray trace model which projects sound level contours onto a two-dimensional display of the surrounding area. This information is sent to the meteorological office for verification, as well as the range control office, and the environmental office. To evaluate the noise level predictions, a series of microphones are located off the reservation to receive the sound and transmit this information back to the central display unit. The computer models are modular allowing for a variety of models to be utilized and tested to achieve the best agreement with data. This technique of prediction and model validation will be used to improve the noise assessment system

    Kepstrum approach to real-time speech-enhancement methods using two microphones

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    The objective of this paper is to provide improved real-time noise canceling performance by using kepstrum analysis. The method is applied to typically existing two-microphone approaches using modified adaptive noise canceling and speech beamforming methods. It will be shown that the kepstrum approach gives an improved effect for optimally enhancing a speech signal in the primary input when it is applied to the front-end of a beamformer or speech directivity system. As a result, enhanced performance in the form of an improved noise reduction ratio with highly reduced adaptive filter size can be achieved. Experiments according to 20cm broadside microphone configuration are implemented in real-time in a real environment, which is a typical indoor office with a moderate reverberation condition

    Influence of Work Environment Noise to Productivity of Employee Performance of Sidoarjo District

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    Employees of the Sidoarjo Regency Health Office have a great responsibility in developing and improving health, especially in Sidoarjo Regency but the location of the Sidoarjo Regency Health Office is less strategic because it is located in the center of the traffic crowd which has an impact on employee performance. This study aims to analyze the noise of the work environment on the productivity of the performance of the employees of the Sidoarjo Regency Health Office. This research was observational analytic type. The sampling technique in this study used total sampling, as many as 30 people. The instruments of this research were questionnaire and sound level meter. Data analysis techniques include editing, coding, data entry, and conducting univariate and bivariate analysis techniques.The results of this study are: the majority of Sidoarjo Health Office employees experience high noise with an average noise intensity of 71.01 dBA; most employees of the Sidoarjo Health Office (56.7%) had good work productivity; and there is an influence of environmental noise on employee performance productivity Sidoarjo Health Office with a pvalue of 0.020 <0.05. To improve employee productivity, employees of the Sidoarjo Health Office are expected to submit noise complaints to the leaders of the Sidoarjo Health Office so that they can be addressed immediately and arrange sitting positions while working away from sources of noise and the Health Office is expected to be able to monitor the noise levels of the workspace of employees and immediately make efforts to reduce employee room noise

    Recognition of 3-D Objects from Multiple 2-D Views by a Self-Organizing Neural Architecture

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    The recognition of 3-D objects from sequences of their 2-D views is modeled by a neural architecture, called VIEWNET that uses View Information Encoded With NETworks. VIEWNET illustrates how several types of noise and varialbility in image data can be progressively removed while incornplcte image features are restored and invariant features are discovered using an appropriately designed cascade of processing stages. VIEWNET first processes 2-D views of 3-D objects using the CORT-X 2 filter, which discounts the illuminant, regularizes and completes figural boundaries, and removes noise from the images. Boundary regularization and cornpletion are achieved by the same mechanisms that suppress image noise. A log-polar transform is taken with respect to the centroid of the resulting figure and then re-centered to achieve 2-D scale and rotation invariance. The invariant images are coarse coded to further reduce noise, reduce foreshortening effects, and increase generalization. These compressed codes are input into a supervised learning system based on the fuzzy ARTMAP algorithm. Recognition categories of 2-D views are learned before evidence from sequences of 2-D view categories is accumulated to improve object recognition. Recognition is studied with noisy and clean images using slow and fast learning. VIEWNET is demonstrated on an MIT Lincoln Laboratory database of 2-D views of jet aircraft with and without additive noise. A recognition rate of 90% is achieved with one 2-D view category and of 98.5% correct with three 2-D view categories.National Science Foundation (IRI 90-24877); Office of Naval Research (N00014-91-J-1309, N00014-91-J-4100, N00014-92-J-0499); Air Force Office of Scientific Research (F9620-92-J-0499, 90-0083

    Sound Event Detection in Synthetic Audio: Analysis of the DCASE 2016 Task Results

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    As part of the 2016 public evaluation challenge on Detection and Classification of Acoustic Scenes and Events (DCASE 2016), the second task focused on evaluating sound event detection systems using synthetic mixtures of office sounds. This task, which follows the `Event Detection - Office Synthetic' task of DCASE 2013, studies the behaviour of tested algorithms when facing controlled levels of audio complexity with respect to background noise and polyphony/density, with the added benefit of a very accurate ground truth. This paper presents the task formulation, evaluation metrics, submitted systems, and provides a statistical analysis of the results achieved, with respect to various aspects of the evaluation dataset

    High quality indoor environments for sustainable office buildings

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    The quality of office indoor environments is considered to consist of those factors that impact occupants according to their health and well-being and (by consequence) their productivity. Indoor Environment Quality (IEQ) can be characterized by four indicators: ‱ Indoor air quality indicators ‱ Thermal comfort indicators ‱ Lighting indicators ‱ Noise indicators. Within each indicator, there are specific metrics that can be utilized in determining an acceptable quality of an indoor environment based on existing knowledge and best practice. Examples of these metrics are: indoor air levels of pollutants or odorants; operative temperature and its control; radiant asymmetry; task lighting; glare; ambient noise. The way in which these metrics impact occupants is not fully understood, especially when multiple metrics may interact in their impacts. While the potential cost of lost productivity from poor IEQ has been estimated to exceed building operation costs, the level of impact and the relative significance of the above four indicators are largely unknown. However, they are key factors in the sustainable operation or refurbishment of office buildings. This paper presents a methodology for assessing indoor environment quality (IEQ) in office buildings, and indicators with related metrics for high performance and occupant comfort. These are intended for integration into the specification of sustainable office buildings as key factors to ensure a high degree of occupant habitability, without this being impaired by other sustainability factors. The assessment methodology was applied in a case study on IEQ in Australia’s first ‘six star’ sustainable office building, Council House 2 (CH2), located in the centre of Melbourne. The CH2 building was designed and built with specific focus on sustainability and the provision of a high quality indoor environment for occupants. Actual IEQ performance was assessed in this study by field assessment after construction and occupancy. For comparison, the methodology was applied to a 30 year old conventional building adjacent to CH2 which housed the same or similar occupants and activities. The impact of IEQ on occupant productivity will be reported in a separate future pape

    From Bentham to Guadet: ‘auditory visibility’ in nineteenth-century theories on government offices

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    Architectural historiography is seldom concerned with the antithetical notions of ‘noise’ and ‘silence’. In this case study, I tentatively explore the theme in the context of nineteenth-century administrative buildings. More particularly, I investigate the normative views of British and French authors concerning acoustic perception in one subtype of ‘bureaucratic’ architecture: the ministerial office building. Drawing examples from the work of, among others, ‘panopticon’ theorist Jeremy Bentham and the architect Julien Guadet, I point at the centrality of ‘sound control’ or ‘sound management’ in architectural discourses on office buildings. In the specific domain of ministerial offices, moreover, these discourses were rife with ideological views on the nature and the functioning of government itself
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