Search results for "canonical analysis"
showing 7 items of 7 documents
A matching task as a potential technique for descriptive profile validation
2003
If panellists can successfully match products to the corresponding descriptive profiles, then the profiles can be regarded as product-relevant and valid. This work examined the ability of a trained panel to perform a matching task between products and their descriptive profiles. A 13-member panel, trained to assess eight cheeses in terms of 19 flavour attributes, performed the task based on their individually developed profiles. The panel's ability to match products to profiles was well above that expected by chance, and chi-square statistics for each of the products were significant (P<0.05). A correspondence analysis based on the group results indicated that all the products were relative…
FLASH table and canonical mapping of potato varieties
2000
International audience
Natural variation of profundal macroinvertebrate communities in boreal lakes is related to lake morphometry: implications for bioassessment
2009
Modern biological assessment of aquatic systems is often based on the reference condition approach, which requires characterization of biota in undisturbed conditions. For this approach, it is essential to recognize the origins and degree of natural variation in communities. We used data from 55 minimally disturbed Finnish lake basins to investigate the natural variation of profundal macroinvertebrate community composition in relation to environmental factors. Partial canonical correspondence analysis showed that most (68% combined, 39% uniquely) of the total explained compositional variation (29%) was correlated with environmental variables insensitive to human activities, especially lake …
Comparison of sampling methods and habitat types for detecting impacts on lake littoral macroinvertebrate assemblages along a gradient of human distu…
2010
We explored environmental variables structuring littoral macroinvertebrate communities in a large lake basin along a gradient of nutrient enrichment. Furthermore, we evaluated sensitivity and cost-effi ciency of different sampling schemes (i.e. combinations of three habitat types and a number of standard sampling methods) to detect changes in macroinvertebrate communities along this anthropogenic disturbance gradient. Partial canonical ordination analysis showed that habitat characteristics accounted for a major part (56 % uniquely) of the explained variation in the species composition of invertebrate communities. When different mesohabitats were examined separately, assemblage variation of…
Influence functions and efficiencies of the canonical correlation and vector estimates based on scatter and shape matrices
2006
In this paper, the influence functions and limiting distributions of the canonical correlations and coefficients based on affine equivariant scatter matrices are developed for elliptically symmetric distributions. General formulas for limiting variances and covariances of the canonical correlations and canonical vectors based on scatter matrices are obtained. Also the use of the so-called shape matrices in canonical analysis is investigated. The scatter and shape matrices based on the affine equivariant Sign Covariance Matrix as well as the Tyler's shape matrix serve as examples. Their finite sample and limiting efficiencies are compared to those of the Minimum Covariance Determinant estima…
On the calculation of derived variables in the analysis of multivariate responses
1992
AbstractThe multivariate regression of a p × 1 vector Y of random variables on a q × 1 vector X of explanatory variables is considered. It is assumed that linear transformations of the components of Y can be the basis for useful interpretation whereas the components of X have strong individual identity. When p ≥ q a transformation is found to a new q × 1 vector of responses Y∗ such that in the multiple regression of, say, Y1∗ on X, only the coefficient of X1 is nonzero, i.e. such that Y1∗ is conditionally independent of X2, …, Xq, given X1. Some associated inferential procedures are sketched. An illustrative example is described in which the resulting transformation has aided interpretation.
Phase transitions in a single polymer chain: A micro-canonical analysis of Wang–Landau simulations
2008
Abstract We present simulation results for the phase behavior of a single chain for a flexible lattice polymer model using the Wang–Landau sampling idea. Using the micro-canonical density of states obtained with this method we will discuss the ability of an analysis in the micro-canonical ensemble to locate the coil-globule (continuous) and liquid–solid (first-order) transitions found for this problem using a canonical analysis.