535,781 research outputs found
Statistical Properties of Single and Competing Non-Linear Fast-Slow Oscillators in Noise
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
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
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
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
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
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
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Assisting the autistic To reduce anxiety caused by their environment
Many people with Autistic Spectrum Disorder (ASD) find certain sounds so unpleasant that their lifestyle can be severely impaired by the need to avoid these noises. This paper considers several common sources of such anxietyinducing noise in the normal home and working environments, and considers whether this problem could be addressed with mechatronic concepts. People with ASD were tested for their reactions to a range of noises, and to the same noises filtered through noise reduction devices. Analysis of the probable characteristics of the anxiety- causing noise features was made. The noises were varying in time and pitch. In addition to anecdotal and survey evidence some carefully structured tests were carried out on some participants using the devices. Based on this investigation, specific mechatronic devices are proposed, using active noise control to selectively soften the sounds, which may be suitably used by those suffering ASD. A smart home or office could deploy multiple devices, in the optimal locations to reduce any offensive noise, whilst preserving a pleasant environment that allows the user the ability to communicate. Furthermore the environment could be tuned to the needs of specific individuals, and switched when they are present
Sound Event Detection in Synthetic Audio: Analysis of the DCASE 2016 Task Results
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
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:
âą Indoor air quality indicators
âą Thermal comfort indicators
âą Lighting indicators
âą 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 Australiaâs first âsix starâ
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: âauditory visibilityâ in nineteenth-century theories on government offices
Architectural historiography is seldom concerned with the antithetical notions of ânoiseâ and âsilenceâ. 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 âbureaucraticâ architecture: the ministerial office building. Drawing examples from the work of, among others, âpanopticonâ theorist Jeremy Bentham and the architect Julien Guadet, I point at the centrality of âsound controlâ or âsound managementâ 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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