Cool stuff

Mole Group
MM Project
VRML widgets





Work phone:
Home phone:
Thomas Kolenda
Trørødkollegiet 2B
DK-2950 Vedbæk
+45 4525 3920
+45 7742 5506
- I received my M.Sc. degree in engineering from the Technical University of Denmark in the fall of 1998. My thesis concerned independent component analysis (ICA), where I studied the principle idea and limits. Also I used the algorithm for analysis of functional brain data in PET and fMRI. I have resently recived my Ph.D in “Modelling tools for shared virtual worlds”. The idea is to apply different statistical modelling techniques to make it easier to navigate and search virtual worlds like the Internet, and combine different multimedia techniques. 

Research activities 

  •  Independent Component Analysis (ICA)

    The activities around ICA has grown fast the last few years and has been applied to many different applications and research areas. As part of my Ph.D. project one objective is to develop tools that can work in different multimedia environments. At the time being I have used ICA in separating sound, pictures and text. A small demonstration file can be downloaded to see ICA preformed on sound and text, click here, or use the DTU:Toolbox.

    Master thesis:

    Introducing ICA in a Bell MME framework and exploring the limits and properties. Problems concerning choosing the unlinear function are looked at experimental by observing the parameter space of the costfunction, and showing that it only results in a scaling of the output. Comparing gradient assent, Natural gradient and the Newton method, different optimization techniques are compared. Especially by looking into the natural gradient the reason for its good performens is explained, partially by the algorithm itself and partially by the parameter space only dependent on the curtosis of the source signals. Finally ICA is used for decomposing fMRI and PET images and showing how well the independents criteria works in comparison to the variance criteria used in PCA. Reducing the number of outputs using PCA the ICA algorithm shows evidence of clustering the components most dependent. For more details se publications.

  • Text analysis

    In the recent years the need to search and maintain and overview in large amounts of data has grown rapidly. This is not only because of the Internet but also because of the growing use of computeres in general.

    Latent semantic analysis (LSA):

    Without having any knowledge of text grammatic and structure in general the LSA method represents the data in such a way that regular statistical methods can be applied directly. 
    Using LSA first, we have used Gaussian-mixture models to cluster the data both using labeled and unlabeled data. One application for this method, is to use this structure directly in the Web SHERPA. For more details se publications.

    ICA applied to text:
    As already suspected in my master thesis the ICA algoritme can be used as an clustering method. As such, using LSA and applying ICA on top of that, can separate groups within the data that results in most independence between the groups. For more details se publications.

  • Virtual worlds

    The two main applications for virtual world modelling are presentation for seismic data and developing tool to help navigate and search. The later is part of a greater ongoing multimedia project by which my Ph.D. grant is given. 

  • Web SHERPA:

    The project develops a WEB-Site HelpER Personalized Agent (WEB-SHERPA) which assists navigation in complex virtual environments. We envision an adaptive agent that can assist in search for specific objects/behaviors in rich 3D environments. Further, as virtual environments proliferate we will need help in negotiating these unknown worlds. WEB-SHERPA shall assist in spatial indexing: by adaptive exploration of a virtual environment, it provides an annotated, view based, overview of a 3D environment (a 3D "street map"). For this we will develop adaptive systems that can resolve spatial and behavioral (incl. emotional) ambiguities, relate 3D structures to object databases, and communicate these in terms of a hyperscript street map. In a later stage we envision WEB-SHERPA to learn from other agents under development, and in this process be enhanced with enhanced communication skills and visualisation capabilities. 
    Try out a demonstration mock-up,  click her.

    Seismic World:
    In order to visualise huge amount of seismic data a VRML model was build with sliding walls, based on the principle used by Finn Nielsen in examining brain data. Doing so makes it easier to find compartments with possible oil or gas resources. Also the model serves as a demonstration and a verification tool. To view screen dumps press [1] or [2].

    Models/Widgets VRML:
    When developing applications different widgets come to life that other VRML 2.0 developer might find useful and are free to use. Click here.


Other activities 

  • Software development

    In order to supply my income during my engineering studies, I have been part of a small consortium that made custom software solutions. The consortium is called CodeGroup and is basically made up of engineers in the fields of information, electronic and construction. Our current project is a program called Sigma for calculating overhead and construction cost in engineering applications. The program is currently available in Danish, German and English and a free trial version can be downloaded from the CodeGroup web page

  • Sports/hobbies

    I have been playing paintball since 1989 and it is one of my biggest passions. Paintball started out in Denmark in 1988 and has ever since been growing steady. I’m currently involved in the Danish Paintball Federation (DPF) that helps to develop and structure paintball in Denmark. Since my studies has been taking up most of my time the resent years, I had to quit my team the Ugly Ducklings in 1997, but hope to take up the more serious part of paintball soon again.