Telos: Representing Knowledge About Information Systems

John Mylopoulos, Alex Borgida, Matthias Jarke, Manolis Koubarakis

Research output: Contribution to journalArticlepeer-review

467 Scopus citations


We describe Telos, a language intended to support the development of information systems. The design principles for the language are based on the premise that information system development is knowledge intensive and that the primary responsibility of any language intended for the task is to be able to formally represent the relevent knowledge. Accordingly, the proposed language is founded on concepts from knowledge representations. Indeed, the language is appropriate for representing knowledge about a variety of worlds related to a particular information system, such as the subject world 1990, the usage world (user models, environments), the system world (software requirements, design), and the development world (teams, metodologies). We introduce the features of the language through examples, focusing on those provided for desribing metaconcepts that can then be used to describe knowledge relevant to a particular information system. Telos' fetures include an object-centered framework which supports aggregation, generalization, and classification; a novel treatment of attributes; an explicit representation of time; and facilities for specifying integrity constraints and deductive rules. We review actual applications of the language through further examples, and we sketch a formalization of the language.

Original languageEnglish (US)
Pages (from-to)325-362
Number of pages38
JournalACM Transactions on Information Systems (TOIS)
Issue number4
StatePublished - Jan 10 1990

All Science Journal Classification (ASJC) codes

  • Information Systems
  • Business, Management and Accounting(all)
  • Computer Science Applications


  • belief time
  • class
  • deductive rules
  • history time
  • instance
  • integrity constraints
  • knowledge base
  • metaclass
  • proposition
  • temporal knowledge

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