The Levenshtein metric, a new means for soil classification tested by data from a sand-podzol chronosequence and evaluated by discriminant function analysis

Soil Research ◽  
1985 ◽  
Vol 23 (2) ◽  
pp. 115 ◽  
Author(s):  
IP Little ◽  
DR Ross

Soil profiles are difficult to compare by statistical methods because sampling depths and intervals and the number of samples per profile may vary. This paper discusses a novel method for handling the problem. Chemical data from 52 soil profiles, which formed a chronosequence of podzols from Fraser Island, south-eastern Queensland, was classified using the Levenshtein metric. The soils varied from undifferentiated sands to deeply weathered podzols with many metres of bleached A, horizon. The data used were the proportions by weight in the soil samples of Na, K, Ca, Mg, Fe and Al extracted by mild acid digests. A polythetic divisive program was used to form seven groups from a matrix of six attributes and 573 samples. These groups were used to code profiles into strings of digits whose length equalled the number of samples in a profile. The Levenshtein metric then formed these strings into a dissimilarity matrix, which in turn was used to produce groups by an agglomerative hierarchical procedure. The groups produced by this procedure were checked using discriminant function analysis applied to depth function parameters derived from the original data set used in the pattern analysis procedures. These parameters were derived from a model which is consistent with ideas of soil genesis, hence their use should favour a classification related to soil development. The classificatory procedure could also be weighted for the depth to the B horizon, a procedure that was considered to be a direct weighting for the degree of soil development. Discriminant function analysis showed that the groups produced could be discriminated on the basis of depth function parameters regardless of any depth weighting. The groups were consistent with the known geochronology, but contained an important component due to other factors such as parent material and surface accumulation due to plant activity. Classification involving the Levenshtein metric proved to be a sound means of taking adequate account of the variation present in the data. Supplementary procedures provided by TAXON enable fresh insights into the nature of the individuals and their interrelationships to be obtained.

2006 ◽  
Vol 23 (3) ◽  
pp. 106-118 ◽  
Author(s):  
Gordon E. Sarty ◽  
Kinwah Wu

AbstractThe ratios of hydrogen Balmer emission line intensities in cataclysmic variables are signatures of the physical processes that produce them. To quantify those signatures relative to classifications of cataclysmic variable types, we applied the multivariate statistical analysis methods of principal components analysis and discriminant function analysis to the spectroscopic emission data set of Williams (1983). The two analysis methods reveal two different sources of variation in the ratios of the emission lines. The source of variation seen in the principal components analysis was shown to be correlated with the binary orbital period. The source of variation seen in the discriminant function analysis was shown to be correlated with the equivalent width of the Hβ line. Comparison of the data scatterplot with scatterplots of theoretical models shows that Balmer line emission from T CrB systems is consistent with the photoionization of a surrounding nebula. Otherwise, models that we considered do not reproduce the wide range of Balmer decrements, including ‘inverted’ decrements, seen in the data.


1988 ◽  
Vol 30 (3) ◽  
pp. 270-283 ◽  
Author(s):  
Stephen Stokes ◽  
David J. Lowe

The microprobe-determined glass shard major element chemistry of tephras derived from five North Island, New Zealand volcanoes (Mayor Island, Okataina, Taupo, Tongariro, and Mount Egmont) and younger than ca. 20,000 yr B.P. was subjected to discriminant function analysis. Four separate approaches were adopted to test the match of the tephras with their known sources: (1) an analysis of raw microprobe data; (2) an analysis of normalized data; (3) an analysis of the data transformed by calculating the log10 of oxide scores divided (arbitrarily) by the chlorine content; and (4) a repeat of (3) with multivariate outlier scores, as determined by principal components analysis, deleted. All yielded excellent classification functions (efficiencies of 91–100%), with the eruptives associated with each of the five volcanoes being chemically distinct from one another. In each approach, the first two canonical discriminant functions accounted for >90% of the variation between groups. The removal of multivariate outliers from the data set had only minor effects on the performance of the discriminant function procedures. Separate discriminant function analysis of the relatively alike Taupo and Okataina eruptives gave a greater degree of multivariate separation. The numerical classifications generated should enable unidentified tephras erupted since ca. 20,000 yr B.P. from the five volcanoes to be provisionally matched with their sources.


1980 ◽  
Vol 19 (04) ◽  
pp. 205-209
Author(s):  
L. A. Abbott ◽  
J. B. Mitton

Data taken from the blood of 262 patients diagnosed for malabsorption, elective cholecystectomy, acute cholecystitis, infectious hepatitis, liver cirrhosis, or chronic renal disease were analyzed with three numerical taxonomy (NT) methods : cluster analysis, principal components analysis, and discriminant function analysis. Principal components analysis revealed discrete clusters of patients suffering from chronic renal disease, liver cirrhosis, and infectious hepatitis, which could be displayed by NT clustering as well as by plotting, but other disease groups were poorly defined. Sharper resolution of the same disease groups was attained by discriminant function analysis.


Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 18
Author(s):  
Long Kim Pham ◽  
Bang Van Tran ◽  
Quy Tan Le ◽  
Trung Thanh Nguyen ◽  
Christian C. Voigt

This study is the first step towards more systematic monitoring of urban bat fauna in Vietnam and other Southeast Asian countries by collecting bat echolocation call parameters in Ho Chi Minh and Tra Vinh cities. We captured urban bats and then recorded echolocation calls after releasing in a tent. Additional bat’s echolocation calls from the free-flying bats were recorded at the site where we captured bat. We used the obtained echolocation call parameters for a discriminant function analysis to test the accuracy of classifying these species based on their echolocation call parameters. Data from this pilot work revealed a low level of diversity for the studied bat assemblages. Additionally, the discriminant function analysis successfully classified bats to four bat species with an accuracy of >87.4%. On average, species assignments were correct for all calls from Taphozous melanopogon (100% success rate), for 70% of calls from Pipistrellus javanicus, for 80.8% of calls from Myotis hasseltii and 67.3% of calls from Scotophilus kuhlii. Our study comprises the first quantitative description of echolocation call parameters for urban bats of Vietnam. The success in classifying urban bats based on their echolocation call parameters provides a promising baseline for monitoring the effect of urbanization on bat assemblages in Vietnam and potentially also other Southeast Asian countries.


2012 ◽  
Vol 60 (4) ◽  
pp. 387-404 ◽  
Author(s):  
Mohamed Agha ◽  
Ray E. Ferrell ◽  
George F. Hart

1986 ◽  
Vol 23 (6) ◽  
pp. 804-812 ◽  
Author(s):  
A. B. Beaudoin ◽  
R. H. King

The magnetite composition from three sets of samples of Mazama, St. Helens set Y, and Bridge River tephras from Jasper and Banff national parks are used to test whether discriminant function analysis can unambiguously distinguish these tephras. The multivariate method is found to be very sensitive to the change in reference samples. St. Helens set Y tephra is clearly distinguished. However, discrimination between Mazama and Bridge River tephras is less distinct. A set of unknown tephras from the Sunwapta Pass area was used to test the classification schemes. Unknown tephras are assigned to different tephra types depending on which reference tephra set is used in the discriminant function analysis.


1967 ◽  
Vol 25 (2) ◽  
pp. 421-436
Author(s):  
Rayman W. Bortner

When statements of formal eligibility requirements fail to account for the characteristics of institutional populations, there is a tendency to resort to speculative explanations. This study examined some methods for empirical evaluations of these speculative notions. Univariate and step-down analyses did not aid in conceptualizing informal selection processes in this study; a discriminant function analysis seemed to provide an adequate approach to a synthesis. The method was illustrated by examining definable subsamples in a VA domiciliary which were compared with a non-institutional, community sample; means of the standardization samples for the tests used provided additional reference points for comparison. For these particular subsamples from this institution, alterations in self concept appeared to provide the single unifying theme which best integrated the diverse differences among the groups.


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