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The paper considers a problem of gemstones valuation, based on real data. The main goal includes constructing a model that determines the evaluated price of a given stone on the basis of its description, expressed as a set of input variables values. A classic approach, utilising a multiple linear regression tool, is compared with nonlinear multilayer perceptrons. As the dataset contains a number of qualitative variables (e.g. gemstone colour purity, the clarity of the structure and a symbol of the certifying autho...

Clustering techniques are frequently applied in business and economy, for example in customer classification, enterprise grouping and in other economic data analysis. This paper presents a new clustering method, based on Delaunay triangulation and iterative aggregation of points distributed in the feature space. In the first part of the article we propose a clustering algorithm that utilises this concept. The algorithm iteratively connects specially selected pairs of nodes in the triangulation mesh and leads to sy...

The paper presents a new, developed by the author, concept of an artificial neural map, named COMSOM and inspired by classic SOM neural networks. The initial part of the article shows a general idea of COMSOM model and its structure, which includes two layers of artificial neurons: input layer (with typical task of distributing input values to data processing neurons) and basic layer containing usually a great number of processing elements, located inside a rectangular part of an XY plane, and able to move freely ...