نتایج جستجو برای: spatial estimates

تعداد نتایج: 527599  

2001
J. Michael Jech John K. Horne

One goal of acoustic-based abundance estimates is to accurately preserve spatial distributions of organism density and size within survey data. We simulated spatiallyrandom and spatially-autocorrelated fish density and bs distributions to quantify variance in density, abundance, and backscattering cross-sectional area estimates, and to examine the sensitivity of abundance estimates to organism ...

2012
Rahel Sollmann Beth Gardner Jerrold L. Belant

When estimating population density from data collected on non-invasive detector arrays, recently developed spatial capture-recapture (SCR) models present an advance over non-spatial models by accounting for individual movement. While these models should be more robust to changes in trapping designs, they have not been well tested. Here we investigate how the spatial arrangement and size of the ...

2007
Danqing Xiao Yu Liu

This paper examined cultural impacts on absolute and relative location estimates of 12 Eastern Chinese cities, based on questionnaires of each city’s latitude and distances between city pairs. Linear regression analysis of the latitude estimates revealed that the estimated latitude of a city is statistically significantly related to its actual latitude. MDS analysis of the distance estimates re...

Journal: :Vision research 1985
R Blake K Holopigian

A two-alternative, spatial forced-choice procedure was used to measure contrast thresholds for detection of sinusoidal gratings that appeared within one-dimensional random noise. The orientation of the noise was symmetrically varied relative to the orientation of the test grating to derive estimates of orientation tuning at two spatial frequencies for both cats and humans. For cats, orientation...

2007
Danqing Xiao Yu Liu Chaowei Yang

This paper examined cultural impacts on absolute and relative location estimates of 12 Eastern China cities, based on questionnaires of each city’s latitude and distances between city pairs. Linear regression analysis of the latitude estimates revealed that estimated latitude of a city is significantly related to its actual latitude. MDS analysis of the distance estimates revealed the gap that ...

Journal: :International Journal of Health Geographics 2004
Olaf Berke

BACKGROUND: There is considerable interest in the literature on disease mapping to interpolate estimates of disease occurrence or risk of disease from a regional database onto a continuous surface. In addition to many interpolation techniques available the geostatistical method of kriging has been used but also criticised. RESULTS: To circumvent these critics one may use kriging along with alre...

2014
Felix Oteng Mensah Clement Alo Sandow Mark Yidana

This study tests the representativeness of groundwater recharge estimates through the chloride mass balance (CMB) method in a tropical environment. The representativeness of recharge estimates using this methodology is tested using evaporation estimates from isotope data, the general spatial distribution of the potential field, and the topographical variations in the area. This study suggests t...

Journal: :Ecological applications : a publication of the Ecological Society of America 2008
Nicholas Wolf Marc Mangel

We describe a novel spatially and temporally detailed approach for determining the cause or causes of a population decline, using the western Alaskan population of Steller sea lions (Eumetopias jubatus) as an example. Existing methods are mostly based on regression, which limits their utility when there are multiple hypotheses to consider and the data are sparse and noisy. Our likelihood-based ...

2006
Moulinath Banerjee

The behavior of maximum likelihood estimates (MLEs) and the likelihood ratio statistic in a family of problems involving pointwise nonparametric estimation of a monotone function is studied. This class of problems differs radically from the usual parametric or semiparametric situations in that the MLE of the monotone function at a point converges to the truth at rate n (slower than the usual √ ...

2002
Kimberly Weems K. S. Weems P. J. Smith

Mixed Poisson regression models, a class of generalized linear mixed models, are commonly used to analyze count data that exhibit overdispersion. Because inference for these models can be computationally difficult, simplifying distributional assumptions are often made. We consider an influence function representing effects of infinitesimal perturbations of the mixing distribution. This function...

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