![](bg9.png)
The first three elements are used to calculate the
reputation, while the two last elements are included
to ensure the integrity and authenticity of the recom-
mendations. The calculation of the reputation score
is based on the dynamic trust evolution model defined
in this paper.
5.2.4 Summary
The dynamic trust evolution model was simple to im-
plement and required no particular configuration by
the users of the WRS. Our preliminary evaluation of
the ratings of recommendations (trust values) deliv-
ered by the WRS indicate that the model behaves as
expected and that the results conform to human intu-
itions.
6 CONCLUSIONS
In this paper, we addressed the problem of auto-
configuration of a trust based security mechanism for
pervasive computing. We presented a novel dynamic
trust evolution function that requires no initial con-
figuration by the user, which makes it particularly
suitable for embedding into mass produced consumer
products. Our evaluation shows that the proposed
function satisfies all the requirements of a trust evo-
lution function and preliminary experiments indicate
results that correspond to human intuition.
Directions for future work include an extension of
the proposed dynamic trust evaluation function to in-
corporate temporal aspects of trust, such as ageing
and forgetability along the lines suggested in Sec-
tion 4.2. We would also like to explore different rates
of adjustments of the shape of the dynamic trust evo-
lution function, i.e., the rate of change of the n value.
REFERENCES
Blaze, M., Feigenbaum, J., Ioannidis, J., and Keromytis, A.
(1999). The role of trust management in distributed
systems security. In Secure Internet Programming,
volume 1603 of Lecture Notes in Computer Science,
pages 185–210. Springer Verlag.
Cahill, V., Gray, E., Seigneur, J.-M., Jensen, C., Chen,
Y., Shand, B., Dimmock, N., Twigg, A., Bacon,
J., English, C., Wagealla, W., Terzis, S., Nixon, P.,
di Marzo Serugendo, G., Bryce, C., Carbone, M.,
Krukow, K., and Nielsen, M. (2003). Using trust for
secure collaboration in uncertain environments. IEEE
Pervasive computing, 2(3):52–61.
eBlogger (2005). EBlogger: On vandalism.
http://eblogger.blogsome.com/2005/10/
24/on-vandalism, accessed 10 June 2008.
Grandison, T. and Sloman, M. (2000). A survey of trust in
internet application. IEEE Communications Surveys
& Tutorials, 3(4):2–16.
Gray, E., Jensen, C., O’Connell, P., Weber, S., Seigneur,
J.-M., and Chen, Y. (2006). Trust evolution poli-
cies for security in collaborative ad hoc applications.
Electronic Notes in Theoretical Computer Science,
157(3):95–111.
Jonker, C. M., Schalken, J., Theeuwes, J., and Treur, J.
(2004). Human experiments in trust dynamics. In
Proceedings of the Second International Conference
on Trust Management (iTrust), pages 206–220, Ox-
ford, U.K.
Jonker, C. M. and Treur, J. (1999). Formal analysis of
models for the dynamics of trust based on experi-
ences. In Proceedings of the 9th European Workshop
on Modelling Autonomous Agents in a Multi-Agent
World : Multi-Agent System Engineering (MAAMAW-
99), pages 221–231, Berlin, Germany.
Korsgaard, T. R. (2007). Improving trust in the wikipedia.
Master’s thesis, Department of Informatics and Math-
ematical Modelling, Technical University of Den-
mark.
Korsgaard, T. R. and Jensen, C. (2008). Reengineering the
wikipedia for reputation. In Proceedings of the 4th
International Workshop on Security and Trust Man-
agement, Trondheim, Norway.
Marsh, P. S. (1994). Formalising Trust as a Computational
Concept. PhD thesis, Department of Mathematics and
Computer Science, University of Stirling.
McKnight, D. and Chervany, N. (1996). The Meanings of
Trust. Technical Report 96-04, University of Min-
nesota, Management Informations Systems Research
Center.
Seigneur, J.-M., Farrell, S., Jensen, C., Gray, E., and Chen,
Y. (2003a). End-to-end trust in pervasive computing
starts with recognition. In Proceedings of the First In-
ternational Conference on Security in Pervasive Com-
puting, Boppard, Germany.
Seigneur, J.-M., Farrell, S., Jensen, C., Gray, E., and Chen,
Y. (2003b). Towards security auto-configuration for
smart appliances. In Proceedings of the Smart Objects
Conference, Grenoble, France.
Weiser, M. (1991). The computer for the 21st century. Sci-
entific American Special Issue on Communications,
Computers, and Networks.
DYNAMICS OF TRUST EVOLUTION - Auto-configuration of Dispositional Trust Dynamics
517