A Coalgebraic Description of Web Interactions

  • Daniela Cancila
  • Furio Honsell
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2841)


We introduce a coalgebraic description of static web sites, whereby pages are modeled by their links to other pages together with some extra information. This information can be either related to the contents or to the presentation or to the architecture of the page, etc., and its granularity can vary. This coalgebraic model provides a formal framework for the analysis of the design of single web sites and for the comparison of different sites. We give two alternative coalgebraic accounts of user visits to a web site, as they arise by extracting the information contained in the log file of the web server. The first one is defined in terms of the notion of injective simulation, the latter in terms of an appropriate lax morphism in Rel. These notions provide formal descriptions of user behaviours and can suggest formal tools for the study of the usability of a site.


Web Site Log File User-Visit Coalgebra Coalgebraic Bisimulation Simulation Relators 


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  1. 1.
    Aczel, P.: Non-Well Founded Sets, Stanford. CSLI Lecture Notes, vol. 14 (1988)Google Scholar
  2. 2.
    Aczel, P., Mendler, N.: A Final Coalgebra Theorem. In: Dybjer, P., Pitts, A.M., Pitt, D.H., Poigné, A., Rydeheard, D.E. (eds.) Category Theory and Computer Science. LNCS, vol. 389, pp. 357–365. Springer, Heidelberg (1989)CrossRefGoogle Scholar
  3. 3.
    Atzeni, P., Mecca, G., Meraildo, P.: To Weave the Web. In: International Conf. on Very Large Data Bases, VLDB 1997, pp. 206–215 (1997)Google Scholar
  4. 4.
    Baltag, A.: A Logic for Coalgebraic Simulation. Electronic Notes in Theoretical Computer Science, vol. 33. Elsevier Science Publishers, Amsterdam (2000)Google Scholar
  5. 5.
    Barwise, J., Moss, L.: Vicious Circles. Lecture Notes, vol. 60. CSLI Publications, Stanford (1996)zbMATHGoogle Scholar
  6. 6.
    Forti, M., Honsell, F.: Set Theory with Free Construction Principles. In: Classe di Scienze, vol. 10(4), pp. 493–522. Annali Scuola Normale Sup. di Pisa (1983)Google Scholar
  7. 7.
    Goguen, J.: An Introduction to Algebraic Semiotics, with Applications to User Interface Design. In: Nehaniv, C.L. (ed.) CMAA 1998. LNCS (LNAI), vol. 1562, pp. 242–291. Springer, Heidelberg (1999)CrossRefGoogle Scholar
  8. 8.
    Goguen, J.: CSE 271 Homepage. User Interface Design: Social and Techinical Issue (Spring 2002),
  9. 9.
    Jacobs, B., Rutten, J.: A Tutorial on (Co)Algebras and (Co)Induction. Bulletin 62, 222–259 (1997)zbMATHGoogle Scholar
  10. 10.
    Lenisa, M.: Themes in Final Semantics. PhD thesis, Dipartimento di Informatica, Università di Pisa (1998)Google Scholar
  11. 11.
    Lisitsa, A., Sazonov, V.: Bounded Hyperset Theory and Web-like data bases. In: Gottlob, G., Leitsch, A., Mundici, D. (eds.) KGC 1997. LNCS, vol. 1289, pp. 172–185. Springer, Heidelberg (1997)Google Scholar
  12. 12.
    Mecca, G., Merialdo, P., Atzeni, P., Crescenzi, V.: The (Short) Araneus Guideto Web-Site Development. In: Second Intern. Workshop on the Web and Databases(WebDB 1999) (1999)Google Scholar
  13. 13.
    Nielsen, J.: Usability Inspection Methods. John Wiley and Sons, Inc., Chichester (1994)Google Scholar
  14. 14.
    Nielsen, J.: Designing Web Usability. New Riders, Indianapolis (2000)Google Scholar
  15. 15.
    Pirolli, P., Pitkow, J., Rao, R.: Silk from a sow’s ear: Extracting esable structures from the web. In: Proceeding of Human Factors in Computing Systems (CHI 1996) Conference, Vancouver, British Columbia, Canada (1996)Google Scholar
  16. 16.
    Rosenfeld, L., Morville, P.: Information Architecture for the World Wide Web. O’Reilly, Sebastopol (1998)Google Scholar
  17. 17.
    Rutten, J.: Relators and metric bisimulations. In: CMCS 1998, Conference Proceeding. ENTCS, vol. 11 (1998)Google Scholar
  18. 18.
    Rutten, J.: Universal coalgebra: a theory of systems. TCS 249, 3–80 (2000)zbMATHCrossRefMathSciNetGoogle Scholar
  19. 19.
    Sazonov, V.: Using Agents for Concurrent Querying of Web-like Databases via a Hyper-Set-Theoretic Approach. In: Bjørner, D., Broy, M., Zamulin, A.V. (eds.) PSI 2001. LNCS, vol. 2244, p. 378. Springer, Heidelberg (2001)CrossRefGoogle Scholar
  20. 20.
    Thijs, A.: Simulation and Fixpoint Semantics. PhD thesis, University of Groningen (1996)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2003

Authors and Affiliations

  • Daniela Cancila
    • 1
  • Furio Honsell
    • 1
  1. 1.Dipartimento di Matematica e InformaticaUniversità di UdineUdineItaly

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