Search results for "correspondence analysis"
showing 10 items of 53 documents
Exploring automatic grouping procedures in ceramic petrology
2004
Although a small number of studies have attempted to introduce automatic grouping procedures into thin section petrography of archaeological ceramics, the majority of studies continue to be carried out by non-automatic means. Although such an approach with the single observer grouping samples has a number of advantages, it is problematic when dealing with large numbers of samples. This paper aims to explore different coding systems and statistical analyses for grouping ceramic thin sections. In the example discussed a number of variables are defined, codified and analysed by correspondence analysis, classical multidimensional scaling, non-metric isotonic multidimensional scaling and Sammon …
A 350,000-year climatic record from the loess sequence of Achenheim, Alsace, France
2008
Up to now the best Quaternary climatic sequences come from oceanic isotope studies, but terrestrial sequences are also well known, usually for pollen or ice core data. A new sequence providing climatic information for the last 500,000 years has been studied in the loess series of Achenheim (Alsace), using the mollusc record in relation to other stratigraphical data. Mollusc assemblages are analysed using a multivariate method. The correspondence analysis used here allows us to explain, in ecological terms, the general variability of the Achenheim set. Most Pleistocene mollusc species have the advantage that modem individuals live in the same assemhlages. So, the known ecology and distributi…
Sign and Rank Covariance Matrices: Statistical Properties and Application to Principal Components Analysis
2002
In this paper, the estimation of covariance matrices based on multivariate sign and rank vectors is discussed. Equivariance and robustness properties of the sign and rank covariance matrices are described. We show their use for the principal components analysis (PCA) problem. Limiting efficiencies of the estimation procedures for PCA are compared.
New insights into the reading of Paleozoic plant fossil record discontinuities
2011
Studying the discontinuity patterns of Paleozoic vascular plants provides a global vision of these key events from the multivariate methods viewpoint. Non-metric multidimensional scaling, detrended correspondence analysis and cluster analysis have been employed together with a set of diversity and abundance measures and an evaluation of the geologic constraints from the plant fossil record data. The results reveal four clear significant discontinuities in terms of taxonomic composition and record representativeness during the early-middle Devonian, Devonian–Carboniferous, Mississippian–Pennsylvanian and early-late Permian. Due to the controversial character of the plant fossil record data a…
Scale-related patterns in the spatial and environmental components of stream macroinvertebrate assemblage variation
2007
Aim We examined the relative contributions of spatial gradients and local environmental conditions to macroinvertebrate assemblages of boreal headwater streams at three hierarchical extents: bioregion, ecoregion and drainage system. We also aimed to identify the environmental variables most strongly related to assemblage structure at each study scale, and to assess how the importance of these variables is related to regional context and spatial structuring at different scales. Location Northern Finland (62–68° N, 25–32° E). Methods Variation in macroinvertebrate data was partitioned using partial canonical correspondence analysis into components explained by spatial variables (nine terms…
Robust Principal Component Analysis of Data with Missing Values
2015
Principal component analysis is one of the most popular machine learning and data mining techniques. Having its origins in statistics, principal component analysis is used in numerous applications. However, there seems to be not much systematic testing and assessment of principal component analysis for cases with erroneous and incomplete data. The purpose of this article is to propose multiple robust approaches for carrying out principal component analysis and, especially, to estimate the relative importances of the principal components to explain the data variability. Computational experiments are first focused on carefully designed simulated tests where the ground truth is known and can b…
Application of the new multimetric MMI_PL index for biological water quality assessment in reference and human-impacted streams (Poland, the Slovak R…
2014
Abstract A new multimetric MMI_PL index, which is based on the macroinvertebrate composition and combines six single key metrics, has already been implemented in Poland according to the requirements of the EU Water Framework Directive. The objectives of our survey were to assess the biological water quality using the new multimetric MMI_PL index in both reference and human-impacted streams, to analyze whether the values of the new multimetric index properly reflect the ecological status of the water in upland and mountain streams as well as to determine which environmental factors influence the distribution of benthic macroinvertebrates and the values of the metrics. The study was carried o…
Ordination analysis and bioindices based on zoobenthos communities used to assess pollution of a lake in southern Finland
1990
The suitability of an ordination method, detrended correspondence analysis (DCA), was tested in assessing the degree of pollution of a large lake on the basis of the zoobenthos communities. Lake Etela-Saimaa, in southern Finland, was originally oligotrophic but is now heavily loaded by effluents from the wood-processing industry. Comparison between areas was complicated by variation in the water depths of the lake sub-basins. A horizontal pollution gradient could, however, easily be detected by means of the DCA in both the profundal and sublittoral zones. The benthic quality index (BQI) based on the composition of the profundal chironomid fauna failed at some stations because the indicator …
Visualization of Jacques Lacan’s Registers of the Psychoanalytic Field, and Discovery of Metaphor and of Metonymy. Analytical Case Study of Edgar All…
2017
International audience; We start with a description of Lacan’s work that we then take into our analytics methodology. In a first investigation, a Lacan-motivated template of the Poe story is fitted to the data. A segmentation of the storyline is used in order to map out the diachrony. Based on this, it will be shown how synchronous aspects, potentially related to Lacanian registers, can be sought. This demonstrates the effectiveness of an approach based on a model template of the storyline narrative. In a second and more comprehensive investigation, we develop an approach for revealing, that is, uncovering, Lacanian register relationships. Objectives of this work include the wide and genera…
European public perceptions of homelessness: A knowledge, attitudes and practices survey
2019
peer-reviewed Background Addressing Citizen’s perspectives on homelessness is crucial for the design of effective and durable policy responses, and available research in Europe is not yet substantive. We aim to explore citizens’ opinions about homelessness and to explain the differences in attitudes within the general population of eight European countries: France, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, and Sweden. Methods A nationally representative telephone survey of European citizens was conducted in 2017. Three domains were investigated: Knowledge, Attitudes, and Practices about homelessness. Based on a multiple correspondence analysis (MCA), a generalized linear mod…