terfezia, picoa and tirmania, so called desert truffles, are mycorrhizal fungi mostly endemic to arid and semi-arid areas of the mediterranean region, where they are associated with helianthemum and carexspecies. the aim of this work was to study the identification, molecular analysis, distribution and hosts of these pezizalean hypogeous fungi in iran. among the specimens, terfezia claveryi, ti...

We compare the statistical analysis of indicator matrices and Burt tables by correspondence analysis (CA) and taxicab correspondence analysis (TCA). There are two new results in this paper. First, TCA of a Burt table corresponds to a particular kind of CA of the indicator matrix based on the centroid decomposition. Second, the response patterns in multiple TCA will be represented as (number of ...

In correspondence analysis, rows and columns of a data matrix are depicted as points in low-dimensional space. The row and column profiles are approximated by minimizing the so-called weighted chisquared distance between the original profiles and their approximations, see or example, Greenacre (1984). In this paper, we will study the inverse correspondence analysis problem, that is, the possibi...

Nonsymmetric correspondence analysis (NSCA) is designed to analyze two-way contingency tables in which rows and columns assume an asymmetric role, e.g., columns depend on rows, but not vice versa. A ridge type of regularization was incorporated into a variety of NSCA: Ordinary NSCA, and Partial and/or Constrained NSCA. The regularization has proven useful in obtaining estimates of parameters, w...

This paper is a non-standard introduction to (multiple) correspondence analysis and nonlinear principal component analysis. We start with a brief introduction to the classical (geometrical) motivation for the technique. We then restart from scratch, using the problem of maximizing an aspect of a multivariable or its correlation matrix. Some general algorithmic considerations are briefly discuss...