scholarly journals REASONABLE SAMPLING SCALE OF MACROPORE BASED ON GEOSTATISTIC THEORY

2009 ◽  
pp. 1443-1450
Author(s):  
Mingyao Zhou ◽  
Zhaodi Lin ◽  
Peng Wu ◽  
Susheng Wang ◽  
Fei Zhang
Keyword(s):  
Sampling Scale

scholarly journals Deep Active Learning for Surface Defect Detection

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1650 ◽  
Author(s):  
Xiaoming Lv ◽  
Fajie Duan ◽  
Jia-Jia Jiang ◽  
Xiao Fu ◽  
Lin Gan
Keyword(s):  
Active Learning ◽  
Object Detection ◽  
Defect Detection ◽  
Surface Defect ◽  
Candidate List ◽  
Detection Model ◽  
Detection Systems ◽  
Learning Framework ◽  
Surface Defect Detection ◽  
Sampling Scale

Most of the current object detection approaches deliver competitive results with an assumption that a large number of labeled data are generally available and can be fed into a deep network at once. However, due to expensive labeling efforts, it is difficult to deploy the object detection systems into more complex and challenging real-world environments, especially for defect detection in real industries. In order to reduce the labeling efforts, this study proposes an active learning framework for defect detection. First, an Uncertainty Sampling is proposed to produce the candidate list for annotation. Uncertain images can provide more informative knowledge for the learning process. Then, an Average Margin method is designed to set the sampling scale for each defect category. In addition, an iterative pattern of training and selection is adopted to train an effective detection model. Extensive experiments demonstrate that the proposed method can render the required performance with fewer labeled data.

scholarly journals Disentangling the effects of sampling scale and size on the shape of species abundance distributions

PLoS ONE ◽  
2020 ◽  
Vol 15 (9) ◽  
pp. e0238854
Author(s):  
Renato A. Ferreira de Lima ◽  
Paula Alves Condé ◽  
Cristina Banks-Leite ◽  
Renata C. Campos ◽  
Malva I. Medina Hernández ◽  
...  
Keyword(s):  
Species Abundance ◽  
Species Abundance Distributions ◽  
Sampling Scale

Spatial sampling scale implications for rainfall induced landslide forecasting

2019 ◽  
Vol 39 (1) ◽  
pp. 42
Author(s):  
Prebble ◽  
Nicol ◽  
Sutherland-Stacey
Keyword(s):  
Spatial Sampling ◽  
Landslide Forecasting ◽  
Sampling Scale

scholarly journals An Interpretation of Cloud Overlap Statistics

2015 ◽  
Vol 72 (8) ◽  
pp. 2877-2889 ◽  
Author(s):  
Adrian M. Tompkins ◽  
Francesca Di Giuseppe
Keyword(s):  
Spatial Scales ◽  
Physical Phenomenon ◽  
Cloud System ◽  
Length Scale ◽  
Clear Sky ◽  
Data Truncation ◽  
Sampling Scale ◽  
The Tropics ◽  
The Impact ◽  
Fractal Cloud

Abstract Observational studies have shown that the vertical overlap of cloudy layers separated by clear sky can exceed that of the random overlap assumption, suggesting a tendency toward minimum overlap. In addition, the rate of decorrelation of vertically continuous clouds with increasing layer separation is sensitive to the horizontal scale of the cloud scenes used. The authors give a heuristic argument that these phenomena result from data truncation, where overcast or single cloud layers are removed from the analysis. This occurs more frequently as the cloud sampling scale falls progressively below the typical cloud system scale. The postulate is supported by sampling artificial cyclic and subsequently more realistic fractal cloud scenes at various length scales. The fractal clouds indicate that the degree of minimal overlap diagnosed in previous studies for discontinuous clouds could result from sampling randomly overlapped clouds at spatial scales that are 30%–80% of the cloud system scale. Removing scenes with cloud cover exceeding 50% from the analysis reduces the impact of data truncation, with discontinuous clouds not minimally overlapped and the decorrelation of continuous clouds less sensitive to the sampling scale. Using CloudSat–CALIPSO data, a decorrelation length scale of approximately 4.0 km is found. In light of these results, the previously documented dependence of overlap decorrelation length scale on latitude is not entirely a physical phenomenon but can be reinterpreted as resulting from sampling cloud systems that increase significantly in size from the tropics to midlatitudes using a fixed sampling scale.

Effects of Heterogeneity in the Spatial and Temporal Pattern of Juvenile Alewife (Alosa pseudoharengus) and Blueback Herring (A. aestivalis) Density on Estimation of an Index of Abondance

1989 ◽  
Vol 46 (9) ◽  
pp. 1564-1574 ◽  
Author(s):  
B. M. Jessop ◽  
W. E. Anderson
Keyword(s):  
Temporal Pattern ◽  
Survey Design ◽  
Simple Random Sampling ◽  
Spatial Density ◽  
Significant Heterogeneity ◽  
Alosa Pseudoharengus ◽  
Near Surface ◽  
Blueback Herring ◽  
Sampling Scale ◽  
Density Pattern

Significant heterogeneity occurred in the spatial and temporal pattern of the nocturnal, near-surface (0 to 1.5 m depth) density of juvenile anadromous alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis) in the Mactaquac Dam headpond, Saint John River, New Brunswick. Juvenile alewife were less available to a pushnet than were blueback herring. Patches of higher density persisted for up to 4 wk for both species. Estimates of patch size depended upon the sampling scale, with larger patches (16 to 58 km long) composed of smaller patches (0.5 to 2.2 km long). The index of aggregation of Taylor's power law was similar for both species pooled value 2.20) Lloyd's index of patchiness varied significantly, for both species, spatially but not temporally, and tended to be higher for blueback herring than for alewife. Density and patchiness differed for both species within and between an upriver, lotic zone and downriver, lentic zone. Mean densities were more precisely estimated at high than at low densities and for alewife than for blueback herring (n = 61). Stratification increased the precision, relative to simple random sampling, of estimates of mean density, particularly at high densities of the more patchily dispersed blueback herring. Autocorrelation occurred in the spatial density pattern of both species at coarse (1–100 km) and medium (0.1–4 km) sampling scales. Variations in the intensity and grain of patchiness may affect the choice of survey design, sample and sample unit size, and frequency of sampling required for a desired precision of density estimates.

scholarly journals Habitat association of plaice, sole, and lemon sole in the English Channel

2006 ◽  
Vol 63 (5) ◽  
pp. 912-927 ◽  
Author(s):  
Hilmar Hinz ◽  
Melanie Bergmann ◽  
Richard Shucksmith ◽  
Michel J. Kaiser ◽  
Stuart I. Rogers
Keyword(s):  
Large Scale ◽  
Prey Availability ◽  
Spatial Scales ◽  
Life Stage ◽  
Adult Life ◽  
Benthic Habitat ◽  
Physical Parameters ◽  
Sampling Scale ◽  
The Subject ◽  
The 19Th Century

Abstract Flatfish have been the subject of scientific research since the beginning of the 19th century, but information on specific habitat requirements of adult life stages is incomplete. This study investigates the association between benthic habitat and the adult life stage of three flatfish species (plaice, sole, and lemon sole). Data from groundfish surveys spanning nine years were used to identify three distinct site groups: sites where a species was consistently abundant, sites of variable or low abundance, and sites at which no fish were caught. We hypothesize that these three site groups should represent a gradient in habitat suitability from highly suitable to unsuitable. Habitat parameters for each site group and species are described and analysed. Besides large-scale physical parameters, the importance of structuring epifauna and prey availability was investigated. Plaice and sole showed similar trends for most abiotic parameters, whereas lemon sole was found over distinctly different habitats. Sediment associations differed between the three species. No clear association was found between flatfish abundance, structuring epifauna, and prey availability within this study. Contradictory results between prey abundance assessed by grab samples and the nutritive state of plaice suggested that the sampling scale used might have been inappropriate to determine prey availability accurately. Plaice appear to sample prey more effectively at the appropriate spatial scales, so the nutritive state of the fish might be a more reliable indicator for prey availability and thus habitat quality.

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