Modern Technologies of Information Integration from Independent Sources and their Application in the Construction of an Information System that Combines Transport Timetables

The problem of constructing an integrating system combining bus timetables of different bus depots is considered. We suppose that these bus depots are independent and, possibly, located at different regions of the country. The purpose of this integrated system is, in particular, the easement of finding available bus routes between two given points. To solve this problem, it is proposed to use an approach combining the advantages of mediator and data repository technologies. The article considers a model of three data sources, which are bus depots that display information about their timetables. It is assumed that all sources have similar conceptual schemes, but they have their own specific characteristics. In particular, there may be different names of tables and attributes in different sources and different distribution of attributes throw tables. Also at some sources may be an absence of certain attributes. We construct correspondence tables and a mediator that translate user queries to the sources. To identify the necessary sources, a small auxiliary repository is maintained that contains information about the stop points served by each of the sources. We describe the technology for updating the repository and the executing strategy for the user query, using the information contained in the repository.