I’m glad to say that the TRECK track of SAC went quite well and did not suffer from some of the things I mentioned in my previous rant. The track was organized by Dr. Jean-Marc Seigneur of the University of Geneva, and the two sessions were chaired by Dr. Virgilio Almeida of the Federal University of Minas Gerais (who I had an interesting discussion with after the track), and was broadly divided into two themes: trust and recommender systems. The trust session had an overall focus on peer-to-peer systems, here are some quick samples:

  • Francesco Santini presented the idea of multitrust, which aims at computing trust in a dynamically created group of trustees who all have different subjective trust values ["Propagating Multitrust Within Trust Networks, " Bistarelli/Santini].
  • Asmaa Adnane presented the application of trust to detecting misbehaviour in link-state routing algorithms. I always wonder how well these cool ideas will work in practice; if information is lost or delayed they will deduce that another node is untrustworthy! ["Autonomic Trust Reasoning Enables Misbehavior Detection in OLSR," Adnane/Timoteo de Sousa/Bidan/Me']
  • The Surework Framework extended the current operation of trust in p2p networks to include the idea of super-peers; nodes with very high reputation can, in fact, become reputation servers. ["Surework: A Super-peer Reputation Framework for p2p Networks," Rodriguez-Perez/Esparza/Munoz]
  • The CAT Model was introduced and explained- it is a model of open and dynamic systems that considers services as contexts.. The 15 minute time-limit was a bit constraining and I’ll have to read the full paper!  ["CAT: A Context-Aware Trust Model for Open and Dynamic Systems" Uddin/Zulkernine/Ahamed]
  • Rowan Martin-Hughes applied a game-theoretic analysis to understand why people would defect in a large-scale open system, like eBay. The analysis was based on a modified version of the Prisoner’s dilemma, which was very interesting; the only question that arises is, as Daniele mentioned, is this appropriate when users may very well behave irrationally? ["Examining the Motivations of Defection in Large-Scale Open Systems," Martin-Hughes/Renz]

The second session focused on recommender systems:

  • Karen Tso-Sutter presented her work on combining user-item tags into the collaborative filtering process. Interestingly, tags did not improve accuracy until the algorithm was already boosted by using both user- and item- based algorithms. ["Tag-Aware Recommender Systems by Fusion of Collaborative Filtering Algorithms," Tso-Sutter/Marinho/Schmidt-Thieme]
  • My work! Looking at the similarity distribution over a graph generated by a nearest-neighbour algorithm. ["The Effect of Correlation Coefficients on Communities of Recommenders," Lathia/Hailes/Capra].
  • Patricia Victor‘s paper discussed an extension to Paolo Massa’s work on trust-aware recommender systems, which concluded that the cold-start problem in recommender systems can be avoided by having users express trust values in other users, which can then be propagated. The problem is: which users should they connect to? The paper has an interesting analysis of the different kind of users in the epinions dataset. ["Whom Should I Trust? The Impact of Key Figures on Cold-Start Recommendations," Victor/Cornelis/Teredesai/De Cock].
  • The last paper veered away from collaborative filtering to look at the role of keywords and taxonomies in content-based recommender systems. The taxonomy vs. folksonomy war continues! ["Comparing Keywords and Taxonomies in the Representation of Users Profiles in a Content-Based Recommender System" Loh/Lorenzi/Simoes/Wives/Oliveira]

The full list of abstracts can be read on the trustcomp-treck web site. If any of the attendees or authors are reading this post: we welcome your thoughts and comments, and officially invite you to contribute to this blog! To write a guest-post about your research, please get in touch! (n.lathia @

7 Responses to “SAC TRECK 2008”

  1. Mohammad Gias Uddin says:

    One paper is missing from this discussion:”CAT: A Context-Aware Trust Model for Open and Dynamic Systems”, Authors: Mohammad Gias Uddin, Mohammad Zulkernine, Sheikh Iqbal Ahamed.

  2. Neal Lathia says:

    Oh no! I’m really sorry; my notes from the track were quite messy :)
    I’ve updated the post. Would you like to write a separate post about the CAT model and your research?

  3. Asmaa Adnane says:

    I am very pleased to participate in this blog. About my work, we are not interested in loss of data because the routing protocol is in the application layer, and thus the problem of data loss is not our problem. After your question at the presentation, I checked the trust rules, and there is only one which poses the problem that you have raised: the rule used to supervise the MPR nodes (if they are sending TC and forwarding data and TC messages of its selector). Thus, we define a period of time to monitor the MPR, and if after that period, the MPR is still inactive (either corrupted or just because of the breakdown in the link), the MPR will be considered as misbehavior! And the node must select another MPR instead of this one.

    Using simulation, we have demonstrated the effectiveness of the verification based on mistrust reasoning in the attack detection. The results allow us to set up verifications that each node can perform to assess the correct behavior of the other nodes and detect attacks against OLSR. this results are submitted in a new paper at WOSIS 2008 (under review:d)

  4. Neal Lathia says:

    hi! welcome to mobblog!
    The reason I asked the question at treck is that evaluating any new, original algorithms in a realistic way seems to still be open to interpretation: just like recommender systems rely on mean error, and routing protocols depend on simulation. In fact- this question reminds me of work being done in the department by Lu Yan.

    As above, would you like to write a separate (more general) post about your work or about the WOIS paper?

  5. Mohammad Gias Uddin says:

    Hi Neal:

    No problem!! Sorry for the late response :-) I was quite busy and forgot the visit the blog. This blog is very good and I will be really happy to participate from now on !!

  6. Michel De Avignon says:

    Dear coleagues, I am trully skeptical about trust systems. One of the authors of the paper about trust in olsr (Timoteo) is very polemic in the university he teaches (Brazil). (he is not considered a serious person there).So, I am very conservative regarding this theme.
    Best regards, but this is my opinion.

  7. It’s sensible to be skeptical. But one also needs to be open-minded – I’m sure you will find few interesting papers on trust management ;-) If you are interested in a particular aspect, pls drop us a line. We will point you to good papers ;-)