scholarly journals Sensorimotor priors in nonstationary environments

2013 ◽  
Vol 109 (5) ◽  
pp. 1259-1267 ◽  
Author(s):  
Devika Narain ◽  
Robert J. van Beers ◽  
Jeroen B. J. Smeets ◽  
Eli Brenner
Keyword(s):  
Environmental Variables ◽  
A Priori ◽  
Past Research ◽  
Systematic Change ◽  
Recent Experience ◽  
Environmental Variance ◽  
Adaptive Models ◽  
Priori Information ◽  
Human Nervous System ◽  
Better Than

In the course of its interaction with the world, the human nervous system must constantly estimate various variables in the surrounding environment. Past research indicates that environmental variables may be represented as probabilistic distributions of a priori information (priors). Priors for environmental variables that do not change much over time have been widely studied. Little is known, however, about how priors develop in environments with nonstationary statistics. We examine whether humans change their reliance on the prior based on recent changes in environmental variance. Through experimentation, we obtain an online estimate of the human sensorimotor prior (prediction) and then compare it to similar online predictions made by various nonadaptive and adaptive models. Simulations show that models that rapidly adapt to nonstationary components in the environments predict the stimuli better than models that do not take the changing statistics of the environment into consideration. We found that adaptive models best predict participants' responses in most cases. However, we find no support for the idea that this is a consequence of increased reliance on recent experience just after the occurrence of a systematic change in the environment.

scholarly journals CONSIDERATIONS ON THE APPLICATION OF THE MAGNETOTELLURIC METHOD WITH NUMERIC MODELING FOR EXPLORATION OF BASINS CONTAINING MAFIC SILLS: THE EXAMPLE OF THE SOLIMÕES UPPER AMAZON BASIN

2017 ◽  
Vol 35 (2) ◽  
Author(s):  
Lúcia Maria da Costa e Silva ◽  
Marcos Kaíre Miguel Sobrinho
Keyword(s):  
Amazon Basin ◽  
A Priori ◽  
Petroleum Exploration ◽  
Seismic Section ◽  
Early Results ◽  
Numeric Modeling ◽  
Magnetotelluric Method ◽  
Priori Information ◽  
Depth Of Investigation ◽  
Better Than

ABSTRACT. The use of the magnetotelluric method (MT) in Brazil has been predominantly focused on understanding large geological structures. In the 80’s the method began to be used in petroleum exploration. Early results have been considered unsatisfactory. We modeled the MT response for the geology of the Solimões Upper Amazon Basin, one of the first basins where MT work was done in Brazil, where basalts sills are common, and showed its difference in comparison with the seismic section. The synthetic seismic sect obtained for the Solimões Basin allows observation of the shallow diabase sill only. However, for MT, the presence of the sill, especially if it is slightly magnetic, increases the depth of investigation possible, or allows the MT method at the very least to investigate the basement better than is possible with the seismic method.Keywords: magnetotelluric, MT, Solimões Basin, diabase sill, modeling, a priori information. RESUMO. O uso do método magnetotelúrico (MT) no Brasil tem sido predominantemente focado na compreensão de grandes estruturas geológicas. Nos anos 80, o método começou a ser usado na exploração de petróleo. Os primeiros resultados foram considerados insatisfatórios. Modelamos a resposta MT para a geologia da Bacia do Solimões, uma das primeiras bacias onde foi realizado levantamento MT no Brasil, onde soleiras de diabásio são comuns, para comparação com a seção sísmica modelada para o mesmo local. A seção sísmica sintética obtida para a Bacia do Solimões permite a observação apenas da soleira de diabásio mais rasa. Entretanto, para o MT, a presença da soleira, especialmente se ela é ligeiramente magnética, aumenta a profundidade de investigação possível, ou ao menos permite que o método MT investigue o embasamento melhor do que é possível com a secção sísmica.Palavras-chave: magnetotelúrico, MT, Bacia do Solimões, soleira de diabásio, modelagem, informação a priori. 

scholarly journals Neural Network for Aerosol Retrieval from Hyperspectral Imagery

2019 ◽  
Author(s):  
Steffen Mauceri ◽  
Bruce Kindel ◽  
Steven Massie ◽  
Peter Pilewskie
Keyword(s):  
Neural Network ◽  
Radiative Transfer ◽  
Surface Albedo ◽  
Hyperspectral Image ◽  
A Priori ◽  
Image Data ◽  
Aerosol Retrieval ◽  
Hyperspectral Image Data ◽  
Priori Information ◽  
Better Than

Abstract. We retrieve aerosol optical thickness (AOT) independently for brown carbon-, dust and sulfate from hyperspectral image data. The model, a neural network, is trained on atmospheric radiative transfer calculations from MODTRAN 6.0 with varying aerosol- concentration and type, surface albedo, water vapor and viewing geometries. From a set of test radiative transfer calculations, we are able to retrieve AOT with a standard error of better than ±0.05. No a priori information of the surface albedo or atmospheric state is necessary for our model. We apply the model to AVIRIS-NG imagery from a recent campaign over India and demonstrate its performance under high and low aerosol loadings and different aerosol types.

scholarly journals Adaptive Randomness: A New Population Initialization Method

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Weifeng Pan ◽  
Kangshun Li ◽  
Muchou Wang ◽  
Jing Wang ◽  
Bo Jiang
Keyword(s):  
A Priori ◽  
Optimization Methods ◽  
Search Space ◽  
Population Based ◽  
Convergence Speed ◽  
Initial Population ◽  
Wide Range ◽  
Priori Information ◽  
Better Than

Population initialization is a crucial task in population-based optimization methods, which can affect the convergence speed and also the quality of the final solutions. Generally, if no a priori information about the solutions is available, the initial population is often selected randomly using random numbers. This paper presents a new initialization method by applying the concept of adaptive randomness (AR) to distribute the individuals as spaced out as possible over the search space. To verify the performance of AR, a comprehensive set of 34 benchmark functions with a wide range of dimensions is utilized. Conducted experiments demonstrate that AR-based population initialization performs better than other population initialization methods such as random population initialization, opposition-based population initialization, and generalized opposition-based population initialization in the convergence speed and the quality of the final solutions. Further, the influences of the problem dimensionality, the new control parameter, and the number of trial individuals are also investigated.

scholarly journals Neural network for aerosol retrieval from hyperspectral imagery

2019 ◽  
Vol 12 (11) ◽  
pp. 6017-6036 ◽  
Author(s):  
Steffen Mauceri ◽  
Bruce Kindel ◽  
Steven Massie ◽  
Peter Pilewskie
Keyword(s):  
Neural Network ◽  
Radiative Transfer ◽  
Surface Albedo ◽  
Hyperspectral Image ◽  
A Priori ◽  
Image Data ◽  
Aerosol Retrieval ◽  
Hyperspectral Image Data ◽  
Priori Information ◽  
Better Than

Abstract. We retrieve aerosol optical thickness (AOT) independently for brown carbon, dust and sulfate from hyperspectral image data. The model, a neural network, is trained on atmospheric radiative transfer calculations from MODTRAN 6.0 with varying aerosol concentration and type, surface albedo, water vapor, and viewing geometries. From a set of test radiative transfer calculations, we are able to retrieve AOT with a standard error of better than ±0.05. No a priori information on the surface albedo or atmospheric state is necessary for our model. We apply the model to AVIRIS-NG imagery from a recent campaign over India and demonstrate its performance under high and low aerosol loadings and different aerosol types.

Innovative Approach to Information Search by Example of a Patent Analysis of an Important Substitution Plan

2020 ◽  
pp. 143-157
Author(s):  
Maria A. Milkova
Keyword(s):  
Information Search ◽  
Topic Modeling ◽  
Cognitive Biases ◽  
A Priori ◽  
Import Substitution ◽  
Innovative Approach ◽  
Iterative Search ◽  
Comprehensive Picture ◽  
Priori Information ◽  
Selection Of

Nowadays the process of information accumulation is so rapid that the concept of the usual iterative search requires revision. Being in the world of oversaturated information in order to comprehensively cover and analyze the problem under study, it is necessary to make high demands on the search methods. An innovative approach to search should flexibly take into account the large amount of already accumulated knowledge and a priori requirements for results. The results, in turn, should immediately provide a roadmap of the direction being studied with the possibility of as much detail as possible. The approach to search based on topic modeling, the so-called topic search, allows you to take into account all these requirements and thereby streamline the nature of working with information, increase the efficiency of knowledge production, avoid cognitive biases in the perception of information, which is important both on micro and macro level. In order to demonstrate an example of applying topic search, the article considers the task of analyzing an import substitution program based on patent data. The program includes plans for 22 industries and contains more than 1,500 products and technologies for the proposed import substitution. The use of patent search based on topic modeling allows to search immediately by the blocks of a priori information – terms of industrial plans for import substitution and at the output get a selection of relevant documents for each of the industries. This approach allows not only to provide a comprehensive picture of the effectiveness of the program as a whole, but also to visually obtain more detailed information about which groups of products and technologies have been patented.

From Isovist to Spatial Perception: Wayfinding in Historic Quarter

2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Chih-Hung Chen ◽  
Ting-Ju Lin ◽  
Chih-Yu Chen
Keyword(s):  
Social Interactions ◽  
Spatial Perception ◽  
Publishing House ◽  
A Priori ◽  
Relative Area ◽  
Social Stimuli ◽  
Historical District ◽  
International Publishing ◽  
A Priori Analysis ◽  
Better Than

Based on the assumption that human behaviours are mainly affected by physical and animate environments, this empirical research takes the changeful and complex historical district in Tainan to observe wayfinding behaviours. An a priori analysis of the isovist fields is conducted to identify spatial characteristics. Three measures, the relative area, convexity, and circularity, are applied to scrutinize the possible stopping points, change of speed, and route choices. Accordingly, an experiment is carried out to observe spatial behaviours and different influences of social stimuli. Results show that social interactions afford groups and pairs to perform better than individual observers in wayfinding.© 2016. The Authors. Published for AMER ABRA by e-International Publishing House, Ltd., UK. Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies, Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, MalaysiaKeywords: wayfinding; isovist; spatial perception and social stimuli; historic quarter

scholarly journals Computational Method for Wavefront Sensing Based on Transport-Of-Intensity Equation

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 177
Author(s):  
Iliya Gritsenko ◽  
Michael Kovalev ◽  
George Krasin ◽  
Matvey Konoplyov ◽  
Nikita Stsepuro
Keyword(s):  
A Priori ◽  
Spherical Wave ◽  
Computational Method ◽  
Optical Systems ◽  
Radius Of Curvature ◽  
Imaging Method ◽  
Wavefront Sensing ◽  
Phase Imaging ◽  
Transport Of Intensity Equation ◽  
Priori Information

Recently the transport-of-intensity equation as a phase imaging method turned out as an effective microscopy method that does not require the use of high-resolution optical systems and a priori information about the object. In this paper we propose a mathematical model that adapts the transport-of-intensity equation for the purpose of wavefront sensing of the given light wave. The analysis of the influence of the longitudinal displacement z and the step between intensity distributions measurements on the error in determining the wavefront radius of curvature of a spherical wave is carried out. The proposed method is compared with the traditional Shack–Hartmann method and the method based on computer-generated Fourier holograms. Numerical simulation showed that the proposed method allows measurement of the wavefront radius of curvature with radius of 40 mm and with accuracy of ~200 μm.

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