Search results

Graph rewriting concerns the technique of transforming a graph; it is thus natural to conceive its application in the evolution of graph databases. This paper aims to propose a two-step framework where rewriting rules formalize instance or schema changes, ensuring graph’s consistency with respect to constraints, and updates are managed by ensuring rule applicability through the generation of side effects: new updates which guarantee that rule application conditions hold.

This paper proposes Schema Evolution Through UPdates, optimized version (SetUp_OPT), a theoretical and applied framework for the management of resource description framework (RDF)/S database evolution on the basis of graph rewriting rules. The framework is an improvement of SetUp which avoids the computation of superfluous side effects and proposes, via SetUpoptND, a flexible and extensible package of solutions to deal with non-determinism.

This paper shows graph rewriting into a practical and useful application which ensures consistent evolution of RDF databases. It introduces an optimised approach for dealing with side effects and a flexible and customizable way of dealing with non-determinism. Experimental evaluation of SetUpoptND demonstrates the importance of the proposed optimisations as they significantly reduce side-effect generation and limit data degradation.

SetUp originality lies in the use of graph rewriting techniques under the closed world assumption to set an updating system which preserves database consistency. Efficiency is ensured by avoiding the generation of superfluous side effects. Flexibility is guaranteed by offering different solutions for non-determinism and allowing the integration of customized choice functions.

The purpose of this study is to test the segmentation based on the usage of sales channels and to compare the segments with each other in terms of socio-demographic and behavioural characteristics.

This study was conducted using representative data collected in Germany through a face-to-face interview. 2,000 German consumers answered questions towards the usage of different sales channels when purchasing wine as well as socio-demographic and other behavioural questions. A hierarchical cluster analysis was run, to classify the respondents into segments.

The results illustrate the usefulness of this kind of segmentation and show significant differences between the six consumer groups: discount-customers, food-retail-customers, supermarket-customers, cellar-door-customers, wine-store-customers and multichannel-customers. These segments differ in their socio-demographic as well as in their behavioural structure. Furthermore, the six segments could be split into two groups depending on their average purchase value: a basic group and a premium group.

This segmentation provides an analysing tool for the German retailers, which is able to identify the loyal and potential consumers of the different sales channels.

This segmentation was conducted using the purchase activity of German consumers in different sales channels. This segmentation approach has been never used to identify, describe and classify wine consumers.