Introduction to Sampling in Space

2006 ◽  
pp. 67-71
Keyword(s):  
Sampling In Space

Corralling of larvae in the deep sea

2001 ◽  
Vol 81 (5) ◽  
pp. 823-826 ◽  
Author(s):  
Cindy Lee Van Dover ◽  
Cheryl D. Jenkins ◽  
Mary Turnipseed
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Frequency Distributions ◽  
Sources And Sinks ◽  
Size Frequency ◽  
Large Numbers ◽  
Local Sources ◽  
Sampling In Space

Large numbers of small individuals (pediveligers and juveniles <5 mm) are routinely recorded in size–frequency distributions of mussel samples collected from deep-sea chemosynthetic environments. If recruitment of invertebrates to deep-sea hydrothermal vent sites were via long-distance dispersal, as is typically assumed, one would expect recruitment ‘events’ recorded in size–frequency distributions to be difficult to detect, due to loss of larvae in an open system over large distances. If one imposes mesoscale oceanographic phenomena that minimize dilution of larvae (such as eddies shed from hydrothermal vent plumes) and episodic spawning, expression of this mesoscale corralling at the level of population structure would likely be limited to discrete records of recruitment events encountered serendipitously during haphazard sampling in space and time. The ubiquity of large numbers of post-larvae in mussel samples from a number of disparate sites is likely not serendipitous, but instead may reflect the importance of local sources and sinks of propagules in maintenance of mussel populations.

scholarly journals Sampling in Space Restricted Settings

Algorithmica ◽  
2017 ◽  
Vol 80 (5) ◽  
pp. 1439-1458
Author(s):  
Anup Bhattacharya ◽  
Davis Issac ◽  
Ragesh Jaiswal ◽  
Amit Kumar
Keyword(s):  
Sampling In Space

Sampling head–rock contact identification for regolith sampling in space

2013 ◽  
Vol 31 (1) ◽  
pp. 108-114 ◽  
Author(s):  
Yun Ling ◽  
Wei Lu ◽  
Aiguo Song ◽  
Hong Zeng
Keyword(s):  
Sampling In Space

Reliability Simulation Combining Kriging and Monte Carlo Radius-outside Importance Sampling in Space Structure Latch

2012 ◽  
Vol 166-169 ◽  
pp. 1872-1878
Author(s):  
Qi Gong ◽  
Jian Guo Zhang ◽  
Duo Su
Keyword(s):  
Monte Carlo ◽  
Importance Sampling ◽  
Limit State ◽  
Joint Probability ◽  
Kriging Model ◽  
Space Structure ◽  
State Function ◽  
Lifetime Analysis ◽  
Initial Sampling ◽  
Sampling In Space

Concerning the issue of high dimensions and low failure probabilities including implicit and highly non-linear limit state function (LSF), the approach of reliability simulation combing Kriging and Monte Carlo Radius-Outside Importance Sampling (MCROIS) is presented, and the Kriging model is to approximate the unknown LSF, then calculate the initial sampling radius of the sphere, and the optimal radius is gained through the iterative algorithm. As such, the joint probability density function of importance sampling is constructed, which ensures that sampling domain is restricted to values outside the sphere located in the design point, and the efficiency is improved. The numerical example of space structure latch demonstrates the efficiency, accuracy and robustness compared with Crude Mote Carlo (CMC), which is validated that the method is of particular interest in applications with a low failure probability of failure, and it realizes the comprehensive design of reliability and wear lifetime on-orbit, and makes contributions to the exploration of reliability and lifetime analysis for the complex aerospace equipment

ELEMENTS OF MIGRATION AND VELOCITY ANALYSIS

Geophysics ◽  
1974 ◽  
Vol 39 (6) ◽  
pp. 811-825 ◽  
Author(s):  
G. H. F. Gardner ◽  
W. S. French ◽  
T. Matzuk
Keyword(s):  
Experimental Model ◽  
Seismic Data ◽  
Random Noise ◽  
Velocity Analysis ◽  
Model Data ◽  
Range Finding ◽  
Adaptive Weighting ◽  
Finite Sampling ◽  
Sampling In Space ◽  
Finding Method

This paper describes a theory for combining migration and velocity analysis of seismic data and uses experimental model data to illustrate some of the practical problems. It is shown that adaptive weighting of the data, based on a measure of coherence, can be effective in suppressing false images and noisy backgrounds caused by finite migration apertures, finite sampling in space and time, and random noise in the data. Velocity analysis is presented as a “range finding” method in which images for two different constant offset profiles are brought into coincidence by using the correct velocity. The method is valid even in the presence of diffraction, dipping interfaces, or curved reflectors.

The nimble node — Million-channel land recording systems have arrived

2019 ◽  
Vol 38 (9) ◽  
pp. 706-714 ◽  
Author(s):  
Ted Manning ◽  
Dinara Ablyazina ◽  
John Quigley
Keyword(s):  
Seismic Data ◽  
Capital Expenditure ◽  
Field Tests ◽  
Environmental Footprint ◽  
Channel System ◽  
Seismic Surveys ◽  
Hot Weather ◽  
Nodal System ◽  
Sampling In Space ◽  
Operational Expenditure

A new nodal land acquisition system is being developed with successful field tests in both cold- and hot-weather settings and is being compared against several existing industry acquisition systems. This nodal system differs from others in that it has been designed to deliver affordable high-quality seismic data with the lightest, smallest, and lowest-cost seismic channel system in the industry by significant margins. There are three main drivers for this innovation. First, it will significantly improve data quality by reducing the current cost barriers to acquiring high-density seismic surveys (i.e., full sampling in space, azimuth, and offset). Second, it will reduce the environmental footprint of land operations (less line clearance required). Third, it will improve the safety of land operations (fewer people and vehicles required per channel). All three have been achieved by dramatically reducing both the capital expenditure to build a one-million-channel highly portable recording system and the operational expenditure needed to operate such a system in the field.

scholarly journals Detecting dominant changes in irregularly sampled multivariate water quality data sets

2018 ◽  
Vol 22 (8) ◽  
pp. 4401-4424
Author(s):  
Christian Lehr ◽  
Ralf Dannowski ◽  
Thomas Kalettka ◽  
Christoph Merz ◽  
Boris Schröder ◽  
...  
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Shallow Groundwater ◽  
Irregular Sampling ◽  
Quality Data ◽  
Data Sets ◽  
Water Quality Data ◽  
Data Set ◽  
Sampling In Space

Abstract. Time series of groundwater and stream water quality often exhibit substantial temporal and spatial variability, whereas typical existing monitoring data sets, e.g. from environmental agencies, are usually characterized by relatively low sampling frequency and irregular sampling in space and/or time. This complicates the differentiation between anthropogenic influence and natural variability as well as the detection of changes in water quality which indicate changes in single drivers. We suggest the new term “dominant changes” for changes in multivariate water quality data which concern (1) multiple variables, (2) multiple sites and (3) long-term patterns and present an exploratory framework for the detection of such dominant changes in data sets with irregular sampling in space and time. Firstly, a non-linear dimension-reduction technique was used to summarize the dominant spatiotemporal dynamics in the multivariate water quality data set in a few components. Those were used to derive hypotheses on the dominant drivers influencing water quality. Secondly, different sampling sites were compared with respect to median component values. Thirdly, time series of the components at single sites were analysed for long-term patterns. We tested the approach with a joint stream water and groundwater data set quality consisting of 1572 samples, each comprising sixteen variables, sampled with a spatially and temporally irregular sampling scheme at 29 sites in northeast Germany from 1998 to 2009. The first four components were interpreted as (1) an agriculturally induced enhancement of the natural background level of solute concentration, (2) a redox sequence from reducing conditions in deep groundwater to post-oxic conditions in shallow groundwater and oxic conditions in stream water, (3) a mixing ratio of deep and shallow groundwater to the streamflow and (4) sporadic events of slurry application in the agricultural practice. Dominant changes were observed for the first two components. The changing intensity of the first component was interpreted as response to the temporal variability of the thickness of the unsaturated zone. A steady increase in the second component at most stream water sites pointed towards progressing depletion of the denitrification capacity of the deep aquifer.

scholarly journals Sampling in Space Restricted Settings

2015 ◽  
pp. 483-494
Author(s):  
Anup Bhattacharya ◽  
Davis Issac ◽  
Ragesh Jaiswal ◽  
Amit Kumar
Keyword(s):  
Sampling In Space
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