(Semantic) Similarity-Blog

Why ballpoint pens and pencils are similar?

Archive for November, 2006

Similarity & GIS - Talks from the SeBGIS 2006 Workshop

Good news for GI scientists interested in semantic similarity and its applications: out of 15 papers accepted for presentation at the SeBGIS workshop co-located with the OTM 2006 Federated Conferences, 3 (in fact 4) were about semantic similarity. The talks are available at http://cs.ulb.ac.be/conferences/sebgis06/ . I will also put the references into the literature section.

Human Subject Test about Role-Filler Similarity

Over the last weeks I have developed a small, web-based human subject test to compare three models of role-filler similarity against human judgments. After an introduction and motivation section, people are asked to rate the similarity between spatial relations, objects and finally combinations of both. The results are compared to those of the computational theories. It turns out that both, the multiplicative approach and the weighted average with automatically determined flexible weightings are potential candidates whereas the simple (unweighted) average does not performed very well (as expected). Moreover there is evidence, that the multiplicative approach tends to underestimate while the weighted average overestimates in general. It took quite a while to really understand how the test should look like, which kind of rating system (sliders) to choose and how to randomize the questions - however I am still not satisfied, especially because sometimes the randomization leads to pairs that are really hard to compare or all dissimilar. I will report on all design decisions made later on.

At the moment the test is available only in German language, but an English version will be online within the next weeks. I will also give full access to the underlaying database, so that everyone interested in human similarity judgments can download and use the results. Until now more than 40 people have participated in the test. Note however, that it is still a pre-test and I will run a face-to-face test with selected participants and a slightly modified test settings in December. Human subject testing is a difficult task and there is a lot of ‘noise’ to be removed (or taken into account) before getting useful result - if you have ideas what can be improved, please comment on this posting.

Role & Filler -Test:  [German Version]

Sim-DL Slides form SeBGIS 2006

Here are the slides from my talk about measuring semantic similarity between concept representations phrased in description logics (such as ALCNR) given at the SeBGIS 2006 workshop in Montpellier/France.You can find all the math behind the framework in the paper. Comments are welcome! [PPT]

SimCat-Project

I am very happy to announce that we, the Ifgi Cognitive Engineering Group (ICEL) and the Muenster Semantic Interoperability Lab (MUSIL), have finally started our SimCat Project. The kickoff meeting was at the 19th October and the Project (funded by the German Research Foundation) will run until November 2008. Of course I will report on the ongoing work, for now here is just a list of topics that we will deal with or have already first results from our previous work. Moreover we have started to develop a similarity server basing on the SIM-DL [73] theory to measure similarity between concepts phrased in various description logics.

List of Topics:

Semantic Similarity (and)
   •Time:
       Concepts evolve over time and therefore also their similarity.

   •Context:
        As Goodman puts it, there is no meaning of similarity without defining its respects.

   •Goals / Affordances:
        Beside context, the goals and abilities of the user have influence on
similarity.
   •Structured Representation:
        Concepts are not bags of features, but have a structure that influences similarity.

   •Representation Extraction:
        How to extract dimensions for geometric similarity approaches out of  databases?

   •As Compromise: 
        The role of similarity in decision support systems involving several users.

   •Generalization:
        Levels of abstractions and their influence on similarity.

   •Description Logics:
        How to measure similarity between DL-concepts (see [73]).

   •Activation/Artificial Neural Networks:
        Can we use neural networks as activation & alignment structures for similairty?

List of Project Participants:

  • Boris Bäumer
  • Martin Espeter
  • Krzysztof Janowicz
  • Carsten Keßler
  • Ilija Panov
  • Martin Raubal
  • Mirco Schwarz
  • Marc Wilkes

Our Project Logo:


[73] Janowicz, K. (2006). Sim-DL: Towards a Semantic Similarity Measurement Theory for the Description Logic ALCNR in Geographic Information Retrieval. R. Meersman, Z. Tari, P. Herrero et al. (Eds.): SeBGIS 2006, OTM Workshops 2006, LNCS 4278, pp. 1681 – 1692, 2006. [PDF] (external link)