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  • 1
    Electronic Resource
    Electronic Resource
    An Objective Method of Weighting in Similarity Analysis (1964)
    [s.l.] : Nature Publishing Group
    Nature 201 (1964), S. 426-426 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It has always been known that these methods may fail if very few attributes are available or if many of the attributes are lacked (or possessed) by nearly all the individuals. This disadvantage is not so marked in Tanimoto's5 method, where the individuals are clustered about a number of apices, or ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/201426a0
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  • 2
    Electronic Resource
    Electronic Resource
    Dissimilarity Analysis: a new Technique of Hierarchical Sub-division (1964)
    [s.l.] : Nature Publishing Group
    Nature 202 (1964), S. 1034-1035 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In the present communication we describe a technique which combines the three advantages of being divisive rather than agglomerative polythetic rather than monothetic, and computationally manageable even on a fairly large scale. Between any two individuals or groups a coefficient of dissimilarity ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/2021034a0
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  • 3
    Electronic Resource
    Electronic Resource
    Partition Correlation Matrices for Heterogeneous Quantitative Data (1962)
    [s.l.] : Nature Publishing Group
    Nature 196 (1962), S. 602-602 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Let the set of values for an attribute x, some of which are zeros, be denoted by a vector [0, x], and let mx be the mean of the non-zero values. Let this vector be regarded as the sum of a qualitative (L) vector [0, mx], in which all non-zero values are replaced by mXf and a quantitative (N) vector ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/196602b0
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  • 4
    Electronic Resource
    Electronic Resource
    Computer assisted tabular sorting of phytosociological data (1973)
    Springer
    Plant ecology 28 (1973), S. 57-73 
    Details
    ISSN: 1573-5052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Sommario Lo scopo di questo articolo monografico è quello di presentare un' applicazione del metodo tradizionale di classificazione ad un computer. In esso vi è descritto l'operazione e l'uso del programma, accompagnato da risultati ottenuti usando due serie di dati ecologici. I'articolo conclude facendo un confronto fra i metodi numerici e il metodo tradizionale ed, in fine, un'introduzione ad un nuovo metodo per la classificazione di dati ecologici con l'assistenza di computers. (Computer-assisted Organisation of Ecological Data).
    Notes: Summary This paper reports an implementation, on a computer, of tabular sorting in the traditional manner. A description is given of the use and usefulness of the program, and an account of its performance with two sets of data is presented. The paper concludes with a comparison of numerical and traditional approaches and an introduction to a new approach for computer assisted organisation of ecological data (COED).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386214
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  • 5
    Electronic Resource
    Electronic Resource
    Numerical methods for the establishment of associations (1975)
    Springer
    Plant ecology 30 (1975), S. 77-87 
    Details
    ISSN: 1573-5052
    Keywords: Association ; Classification ; Simulation ; Vegetation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung In dieser Arbeit werden einige der möglichen Gründe für die Diskrepanz zwischen den üblichen Tabellen-Ordnungsverfahren und numerischen Klassifikationsmethoden besonders in der Vegetation des tropischen Regenwaldes, untersucht. Ein neues Verfahren für die Organisation numerischer Daten wird vorgeschlagen. Mit diesem Verfahren wird diese Diskrepanz vermieden und eine natürliche und operationelle Definition der Assoziation erreicht. Diese Definition verbindet die Assoziation mit dem Organisationsniveau auf welchem die Struktur der Daten von diskontinu in kontinu übergeht. Das Verfahren stellt auch die Konstanz- und Dominanzkoeffizienten fest und ermöglicht eine numerische Schätzung des Treuegrads. Ein Beispiel der Anwendung dieses Verfahrens wird für tropische Regenwaldvegetation in North Queensland gegeben.
    Notes: Summary This paper examines some of the possible reasons for discord between traditional tabular sorting and methods of numerical classification particularly in rainforest vegetation. A new method of numerical data organisation is introduced to avoid these problems which leads to a natural and operational definition of the Association. This definition relates the Association to the organisational level at which data structure changes from discontinuous to continuous. The method also establishes coefficients of constancy and dominance for species and permits numerical assessment of fidelity. An example is given of the application of the method to tropical rainforest vegetation in North Queensland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02389609
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  • 6
    Electronic Resource
    Electronic Resource
    On objectives of methods of ordination (1975)
    Springer
    Plant ecology 30 (1975), S. 15-32 
    Details
    ISSN: 1573-5052
    Keywords: Catenation ; Factor analysis ; Interpretation ; Ordination ; Path Seeking ; Principal Components Analysis ; Scaling ; Simplification ; Unfolding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The objectives of a number of methods of ordination are examined and a major distinction made between two approaches. The first of these has as a primary objective the efficient redescription of data, and is typified by principal components analysis. However the linear additive model implied in component analysis and the predominance of unique variance, together with lack of scale invariance suggests that other methods of dimensionality reduction might be more appropriate ecologically—either the non-metric methods of multidimensional scaling or the methods of factor analysis. The second approach, typified by Curtis and McIntosh continuum analysis, seeks to order the stands so that the resulting data matrix has a particular form, and is not directly concerned with dimensionality reduction. Continuum analysis is not the only such pathseeking method, and the objectives of several others are briefly examined. Finally the methods of Hill for seriation and the intrinsic dimensionality approach of Trunk seem to provide methods close to those required for the examination of ecological data. Concluding comments are made on problems of interpretation and the effects of sampling and description on the value of the results, especially in the light of the present tendency to employ simulated data to test the efficacy of methods of analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02387874
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  • 7
    Electronic Resource
    Electronic Resource
    Similarity measures for structured data: a general framework and some applications to vegetation data (1989)
    Springer
    Plant ecology 81 (1989), S. 41-60 
    Details
    ISSN: 1573-5052
    Keywords: Classification ; Frequency distribution ; Graph ; Levenshtein distance ; Profile ; Richness ; String ; Succession ; Transect ; Tree ; Weighting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although there are many measures of similarity existing in the phytosociological literature, these almost all apply to data for which the describing attributes have only single values. In many cases, however, there can be a richer structure in the attribute values, either directly from the nature of the attributes or derived from relationships between the stands. In this paper, I first examine a range of possible sources of such structure in phytosociological data, and then propose a similarity measure sufficiently general to be applicable to all the variant types. Finally I present some examples of applying such measures to frequency data from tropical grasslands and to successional data from subtropical rain forest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045512
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  • 8
    Electronic Resource
    Electronic Resource
    Dissimilarity for partially ranked data and its application to cover-abundance data (1989)
    Springer
    Plant ecology 82 (1989), S. 1-12 
    Details
    ISSN: 1573-5052
    Keywords: Distance ; Hausdorf distance ; Levenshtein distance ; Ordered category ; Rank correlation ; Similarity ; String ; Transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cover-abundance estimates are commonly employed in phytosociological investigations to record the performance of species. Because the coded values are on an ordinal scale of measure, various authors have suggested that some transformation is necessary before such values can be used for classification and ordination. However, it is not clear that transformation is a sufficient treatment, and it would seem preferable to use ordinal data directly. In this paper we examine such direct use of partial rankings and show that several dissimilarity measures can be defined for this case without invoking any transformations. They include dissimilarity measures associated with various rank correlation measures and with distances between strings; all the measure are variant forms of Hausdorf's interset distance. Certain other kinds of data, such as those employing dominant and subdominant species and the dry-weight-rank estimation of biomass, are also on an ordinal scale and could be analysed using similar techniques. To illustrate the approach, a string dissimilarity measure is used to analyse a set of data from Slovakian grasslands which appear to reflect a simple gradient. The original data were recorded with 10 classes of performance and are analysed using hierarchical and nondeterministic, overlapping, classifications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217977
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  • 9
    Electronic Resource
    Electronic Resource
    A syntactic basis of classification (1980)
    Springer
    Plant ecology 42 (1980), S. 93-98 
    Details
    ISSN: 1573-5052
    Keywords: Classification ; Ecological grammar ; Semantics ; Syntax
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00048875
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  • 10
    Electronic Resource
    Electronic Resource
    Classification of vegetation sequences in Toohey Forest, Queensland (1988)
    Springer
    Plant ecology 76 (1988), S. 113-129 
    Details
    ISSN: 1573-5052
    Keywords: Levenshtein distance ; Sequence ; Transect ; Vegetation landscape ; Vegetation unit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this paper we consider one method of mapping larger units identified from the spatial pattern of sequences of vegetation types. The basic data were presence/absence data for 6450 stands arranged in 90 transects. A second set of data was derived by averaging the species occurrences in non-overlapping groups of 5 stands. A divisive numerical classification was used to determine the primary vegetation units. In all, 5 different sets of primary types were derived, using different species suites, different sample sizes and different numerical methods. We briefly discuss the types identified and their spatial patterns in the area. Each of these types was then used to define a string of ‘type-codes’ for every transect so that each transect represents a sample from the landscape containing information on the frequency and spatial distribution of the primary vegetation types. The transects may be classified using a Levenshtein dissimilarity measure and agglomerative hierarchical classification, giving 5 analyses of transects, one for each of the primary types discussed above. We then examine these transect classifications to investigate the stability of the vegetation landspace patterns under changes in species used for the primary classification, in size of sample unit and in method of primary classifications. There is a considerable degree of stability in the results. However it seems with this vegetation that the tree species and non-tree species have considerable independence. We also indicate some problems with this approach and some possible extensions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045473
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