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In this paper, we present an empirical study on convergence nature of Differential Evolution (DE) variants to solve unconstrained global optimization problems. The aim is to identify the convergence behavior of DE variants and compare. We have chosen fourteen benchmark functions grouped by feature: unimodal separable, unimodal nonseparable, multimodal separable and multimodal nonseparable. Fourteen variants of DE were implemented and tested on these problems for dimensions of 30. The variants are well compared by their Convergence Speed, Quality Measure and Population Convergence Measure. [ABSTRACT FROM AUTHOR]

Koinéisation in medieval times may have involved the emergence in Paris of a new, relatively stable mixture of dialect features, but it did not entail homogeneity, as we have seen. Persistent and often violent demographic fluctuation in the ‘proto-industrial period’ favoured more variation in language, not less. The first explicit moves to suppress such variation and establish a standard language come with the Renaissance, and it is the process of disentangling standard and vernacular in the speech of the early modern city which will provide the focus for Part 3. In the fourteenth century, according to Hohenberg and Lees (1985), European cities entered a new stage of development, which lasted until the onset of industrialisation four hundred years later. The feature of proto-industrial development that impacts most on the sociolinguistic situation in Paris is an increase in hierarchical thought, which widens the gulf between the culture and life-style of the elites and those of the population at large. This is compounded in Renaissance Europe by the spread of literacy, which accentuates the divergence between the written culture of the elites and the traditional oral culture of the masses. A new polarity crystallises in the social psychology of the city, setting ‘urbanity’ against ‘rusticity’. In this new cultural setting, Latin is progressively restricted to its religious functions, and variation within the vernacular takes on a social importance that it appears not to have had previously. [ABSTRACT FROM AUTHOR]