Computer Science Colloquium, Groningen Colloquium Informatica and Johann-Bernoulli-Colloquium

Johann Bernoulli Institute for Mathematics and Computer Science, University of Groningen

coordinators: Michael Biehl (m dot biehl at rug dot nl) and Marco Aeillo (aiellom at cs dot rug dot nl)

Talks should be addressed to a rather broad audience, including advanced students, who we encourage to attend the colloquia. As a speaker, please provide an abstract and title at least two weeks before the talk so we can advertise it properly.

  Please contact M. Biehl or M. Aiello for suggestions of talks.
Note: Every second Monday of the month is reserved for the Faculty Spotlight talks of FWN


Earlier talks

if not otherwise indicated, the colloquium will be
held in room 5161.0267 (Bernoulliborg), Monday, 16:00

click title for abstract (if available)

2010

  •   Wednesday, 24 November
    Johann Bernoulli Colloquium
    Massimo Franceschet
    Univ. Udine, Italy
    Details to be announced
    invited by: JBI

  •   15 November
    P.J. Neirotti
    How to construct a good student
    Aston University, Birmingham/UK
    invited by: M. Biehl

  •   18 October
    Anne Hoffmann
    Siemens Wind Power A/S, Brande/Denmark
    IMProject - Using Improvisation Theater Techniques in Project Management
    invited by: P. Avgeriou

  •   11 October
    Pieter R. Roelfsema
    Netherlands Inst. of Neuroscience, Amsterdam
    Seeing and feature-binding in the visual brain
    invited by: N. Petkov

  •   22 September (Wednesday!)
    N.C. Narendra
    IBM Research India, Bangalore
    Dynamic Provisioning in Multi-Tenant Service Clouds
    invited by: M. Aiello

  •   Monday, 20 September
    Johann Bernoulli Colloquium
    Peter Grünwald
    CWI Amsterdam and Universiteit Leiden
    Updating probabilities and characterizing CAR: when conditioning succeeds and when it fails
    invited by: JBI

  •   13 September
    M. Aksit
    Twente University
    Software Composition: from Objects, Aspects to Architecture Composition
    invited by: P. Avgeriou

  •   2 September (Thursday)
    F. Smeraldi
    Queen Mary, University of London
    Ranklets: a family of multiscale orentation selective rank features
    invited by: G. Azzopardi

  •   9 August
    D. Zühlke
    Fraunhofer Institute FIT, St. Augustin, Germany
    Neural Computation in industrial applications of life science informatics
    invited by: M. Biehl

  •   5 July
    Tobias Hesselmann
    OFFIS, Oldenburg/Germany
    to be announced
    invited by: T. Isenberg

  •   21 June, Monday, 14:00-18:00
    Harmoniegebouw, Oude Kijk in't Jatstraat 26, room 15.00.42
    Second Mini Symposium "Machine Learning and beyond"
    Tentative program:
    14:00     T. Heskes (Nijmegen): Approximating marginals in latent Gaussian models
    14:40     T. Villmann (Mittweida): Divergence based similarity measures
    15:20     break
    15:50     J. van Mourik (Aston): New strategies for agent based optimisation
    16:30     P. Tino (Birmingham): One-shot Learning of Poisson Distributions
                - Information Theory of Audic-Claverie Statistics for Analysing cDNA Arrays
    17:10     M. Opper (Berlin): Switching regulatory models
    17:50     conclusion

    for last minute information, please contact M. Biehl (m.biehl at rug.nl)

  •   15 June, Tuesday, Room 0267, 8:45-14:00
    First Mini Symposium "Machine Learning and beyond"
    Tentative list of speakers and preliminary program:
    8:45     Opening
    9:00     F.-M. Schleif (Bielefeld): Recent extensions of evolving trees for the identification of bacteria spectra
    9:45     B. Hammer (Bielefeld): Topographic maps for very large relational data sets
    10:30   coffee break
    11:00   J. Steil (Bielefeld): Constraint regularization of recurrent networks
    11:45   M. Verleysen (Louvain La Neuve): Using SVMs with randomized feature spaces: an extreme learning approach
    12:30   coffee break
    13:00   T. Martinetz (Lübeck): LVQ-Neural-Gas
    13:45   conclusion, lunch

    For the final program, visit this web page or contact M. Biehl (m.biehl at rug.nl) shortly before the event

  •   9 June (Wednesday, room to be announced)
    Joyce Westerink
    Philips Research, Eindhoven
    Unobtrusive Emotion Sensing in Everyday Life
    invited by: N. Petkov

  •   31 May
    Dusko Jovanovic
    Neopost Technologies
    to be announced
    invited by: P. Avgeriou

  •   17 May
    Thomas Villmann
    Divergence based on-line Vector Quantization for functional data
    Hochschule Mittweida/Germany
    invited by: M. Biehl

  •   10 May
    Giacomo Cabri
    Univ. di Modena e Reggio Emilia
    Engineering interactions between distributed components: some approaches applied to software agents
    invited by: M. Aiello

  •   26 April
    Bernhard Burgeth
    Saarland University
    to be announced
    invited by: J. Roerdink

  •   Wednesday, 17 March
    Johann Bernoulli Colloquium (room 267, 16:15)
    Freek Wiedijk
    Nijmegen
    Why most proofs eventually will be computer checked, and why this time has not arrived yet
    invited by: JBI

  •   8 March
    Natasa Grgurina
    RUG Centre for Learning and Teaching
    CS in Dutch Secondary Education
    invited by: G. Renardel and J. Roerdink

  •   22 February
    no colloquium, date reserved for docent-van-het-jaar-uitreiking
    contact: Inge Slingerland (ingeslingerland at gmail dot com)

  •   16 February (TUESDAY, 16:00, Room 289)
    Peter Riegler
    University of Applied Sciences Wolfenbüttel/Germany
    Computer Assisted Evaluation
    invited by: M. Biehl and S. Achterop

  •   15 February
    Luca Di Gaspero
    University of Udine
    to be confirmed
    invited by: M. Aiello

  •   12 February (FRIDAY)
    Han Slootweg
    Enexis and TU/e
    details to be announced
    invited by: M. Aiello


    2009

  •   30 November
    Fons Verbeek
    Leiden Inst. of Advanced Computer Science
    details to be announced
    invited by: J. Roerdink

  •   23 November
    Klaus Toennies
    Univ. Magdeburg / Germany
    Hierarchical models of shape and appearance for segmentation and object detection in medical images
    invited by: N. Petkov

  •   16 November
    Frank-Michael Schleif
    Univ. Leipzig / Germany
    Sparse Models for the Decomposition of Spectral Data
    invited by: M. Biehl

  •   Thursday 12 November, 16:00, room 280
    John Quinn
    Makerere University, Kampala/Uganda
    Extreme Traffic Monitoring using Probabilistic Inference
    invited by: M. Biehl

  •   19 October
    Jasper van de Gronde
    The iGem project
    invited by: J. Roerdink

  •   29 June
    Thomas Villmann
    Hochschule Mittweida / Germany
    details to be announced
    invited by: M. Biehl

  •   Thursday 25 June, Room 267 Bernoulliborg, 15:30
    Michael Seifert
    Leibniz Institute for Plant Genetics, Gatersleben/Germany
    HMM-based detection of polymorphic regions in genomes of Arabidopsis ecotypes
    invited by: M. Biehl

  •   15 June
    Nicolas Guelfi
    University of Luxembourg
    details to be announced
    invited by: P. Avgeriou

  •   11 May
    Stephan Lukosch
    TU Delft
    Facilitating Audio-based Collaborative Storytelling for Informal Knowledge Management
    invited by: P. Avgeriou

  •   27 April
    date reserved for
    Master meeting for CS students
    details to be announced

  •   Thursday, 23 April, Room 253 (Bernoulliborg), 14:00
    Chris Huyck, Middlesex University
    Cell Assembly Robots: Vision and Cognitive Modelling
    invited by: N. Petkov

  •   20 April
    Lai Xu (SAP Research)
    SOA4All: Service Oriented Architectures for All
    Paul de Vrieze (SAP Research)
    An ontological approach to handling web service change
    invited by: M. Aiello

  •   19 January
    David J. Smith
    University of Birmingham, UK
    to be announced
    invited by: M. Biehl


    2008

  •   1 December
    Michel Wermelinger
    The Open University, UK
    Design Principles in Architectural Evolution: a Case Study
    invited by: P. Avgeriou

  •   6 November (Thursday, 16:00 !!!)
    Jesper Anderson
    Vaxjo University, Sweden
    details to be announced
    invited by: P. Avgeriou

  •   30 October (Thursday!)
    Uwe Zdun
    TU Vienna
    Compliance in service-oriented architectures: a model driven and view-based approach
    invited by: P. Avgeriou

  •   23 October (Thursday!)
    David G. Stork
    Ricoh Innovations and Stanford University
    When computers look at art: Computer vision and image analysis in humanistic studies of visual arts
    invited by: M. Wilkinson

  •   20 October
    Barbara Hammer
    TU Clausthal
    Clustering and Visualization of Large Dissimilarity Datasets
    invited by: M. Biehl

  •   13 October
    Stefan Tai
    Univ. Karlsruhe
    Cloud Computing: On-demand compute utilities - and opportunities - in the hands of many
    invited by: M. Aiello

  •   6 October (2 talks in room 5161.0253, 15:00 and 16:00)
    Antony Tang (15:00)
    Swinburne University of Technology, Australia
    Towards Independent Software Architecture Review
    invited by: P. Avgeriou

    Sheelagh Carpendale (16:00)
    Univ. of Calgary
    Observation for design
    invited by: T. Isenberg

  •   8 September
    Olaf Zimmermann
    IBM Zurich
    Reusable Architectural Decision Models for Enterprise Application Develpment
    invited by: Paris Avgeriou

  •   16 July
    Lorenzo Alvisi
    Univ. of Texas
    (to be announced)
    invited by: M. Aiello

  •   30 June
    Loris Penserini
    Univ. Utrecht
    Dealing with Adaptivity Qualities within different Agent-Oriented Development Frameworks
    invited by: M. Aiello

  •   23 June
    Gintautas Dzemyda
    Inst. of Mathematics and Informatics, Vilnius/Lithania
    Visualization of Multidimensional Data by Using Neural Networks: Methods and Applications
    invited by: J. Roerdink

  •   20 June
    Esra Erdem
    Inferring phylogenetic trees using answer set programming
    invited by: M. Aiello

  •   16 June
    Wiero Niessen
    Image Analysis for developing Quantitative Imaging Biomarkers
    invited by: N. Petkov

  •   9 June
    Til Ach
    RWTH Aachen
    Analysing Superimposed Oriented Patterns
    invited by: N. Petkov

  •   19 May
    Jan Sijbers
    Univ. of Antwerp
    Diffusion tensor imaging: current and future research at Vision Lab Antwerp
    invited by: Jos Roerdink

  •   6 May (Tuesday!), 11:00, room 105 (Bernoulliborg)
    Isabelle Bloch
    Telecom Paris Tech (ENST)
    Fuzzy morphology and its applications to spatial reasoning
    invited by: M. Aiello

  •   14 April
    Arnold Smeulders
    Intelligent Systems Lab Amsterdam
    The notion of an object in computer vision
    invited by: N. Petkov

  •   7 April
    Dr. Frank-Michael Schleif
    Univ. Leipzig/Germany
    Algorithms for spectral data analysis and applications
    invited by: M. Biehl

  •   31 March
    Johan Jeuring
    Univ. Utrecht and OU
    Strategies for exercises
    invited by: P. Avgeriou

  •   17 March
    Georgios Ouzounis
    Intelligent Systems
    Hyper-connectivity, operators and applications
    invited by: M. Wilkinson

  •   10 March
    Gerard de Haan
    Video Processing Group, Philips Research, Eindhoven
    Moving images on modern displays: How to choose your next flat screen TV
    invited by: N. Petkov

  •   3 March
    Thomas Villmann
    Univ. Leipzig
    Fuzzy classification and class-imaging using fuzzy-labelled self-organizing maps
    invited by: M. Biehl

  •   25 February
    Fabrice Rossi
    INRIA Rocquencourt/France
    An introduction to functional data analysis
    invited by: M. Biehl

  •   22 February
    Maia Angelova
    Northumbria University, Newcastle/UK
    Combined clustering models for the analysis of gene expression of prokaryotic organisms
    invited by: N. Petkov

  •   18 February
    Max Viergever
    Univ. Utrecht
    Image Registration and Fusion for Medical Research, Diagnosis and Intervention
    invited by: N. Petkov

  •   11 February
    Lucas J. van Vliet
    Pattern Recognition Group, Dept. Applied Physics, TU Delft
    Robust Super-Resolution: Algorithms and Performance Measures
    invited by: N. Petkov

  •   4 February
    Tobias Isenberg, IWI
    Illustrative Computer Graphics, Visualization, and Interaction

  •   1 February (FRIDAY!), room 267 (Bernouilliborg), 11:00 -13:00
    B. Preim, Univ. Magdeburg
    Visual Computing for medical education, diagnosis and treatment planning
    and
    J.J. van Wijk, TU Eindhoven
    Visualization of Seifert Surfaces

  •   28 January
    Farhad Arbab
    CWI, Amsterdam and Univ. Leiden
    Third-Party Coordination of Distributed Services
    invited by: M. Aiello

  •   21 January
    Natasa Grgurina
    Computer Science in Higher Education
    invited by: G. Renardel

  •   14 January
    I. Aizenberg
    Texas A&M University, Computer and Information Sciences
    Multi-Valued and Universal Binary Neurons
    Presentation (pdf) available here
    invited by: N. Petkov


    2007

  •   17 December
    Alex Telea, IWI
    t.b.a.

  •   3 December (Monday, 15:30)
    Michel Verleysen
    Univ. catholique de Louvain
    High-dim. data analysis: the curse of dimensionality, feature selection and dimensionality reduction
    invited by: M. Biehl

  •   26 November
    E.A. Valentijn
    FWN - Sterrenkunde
    t.b.a.
    invited by: N. Petkov

  •   19 November
    Jose Quenum
    Makerere University, Kampala/Uganda
    Interaction Design in Complex Adaptive Systems: A Generic Protocol-based Approach
    invited by: M. Aiello

  •   6 November (Tuesday, 13:00, room WSN 5412.0035)
    John Quinn
    Makerere University, Kampala/Uganda
    Detecting unusual dynamics in sequences of physiological data
    invited by: M. Biehl

  •   5 November (Monday, 15:30)
    Pierre America
    Philips Researchs, Healthcare Systems Architecture, Eindhoven
    How to get your architecture prepared for the future?
    invited by: P. Avgeriou

  •   29 October (Monday, 15:30)
    W.J. van den Heuvel
    Tilburg University
    t.b.a.
    invited by: M. Aiello

  •   22 October (Monday, 15:30)
    Paolo Ferragina
    University of Pisa
    Compressing and indexing strings and labeled trees
    invited by: M. Aiello

  •   8 October (Monday, 16:15)
    Krysztof R. Apt
    CWI and University of Amsterdam
    Infinite Qualitative Simulations by Means of Constraint Programming
    invited by: M. Aiello

  •   11 June (Monday, 15:30) no colloquium, reserved for an afstudeercolloquium

  •   21 May (Monday, 15:30)
    Andrea Cali
    Univ. Bozen - Bolzano
    Checking conjunctive query containment under relational constraints
    invited by: M. Aiello

  •   2 April (Monday, 15:30)
    Dr. Frank-Michael Schleif
    Univ. Leipzig/Germany
    New perspectives in data analysis and biomarker detection for spectrometric measurements in medicine
    invited by: M. Biehl

  •   26 March (Monday, 15:30)
    Hans van Hateren
    new group member, Intelligent Systems
    Encoding of high dynamic range video with a model of human cones
    invited by: Intelligent Systems group

  •   19 March (Monday, 15:30) (WSN 25!)
    Prof. Alexander Tuzikov
    National Academy of Sciences of Belarus
    Geometric moment computation for polygonal shapes and objects with a spline boundary
    invited by: J. Roerdink

  •   12 March (Monday, 15:30)
    Prof. Peter Riegler
    FH Wolfenbüttel/Germany
    Culinary Informatics
    invited by: M. Biehl

  •   26 February (Monday, 15:30, room BB217)
    Dr. Maarten W.A. Steen
    Telematica Instituut
    Modelling service semantics for discovery and integration
    invited by: M. Aiello

  •   26 January (Friday, 10:00, room BB 217 )
    Prof. Reinhard Klette
    Auckland University, New Zealand
    Rubberband algorithms for solving various 2D or 3D shortest path problems
    invited by: N. Petkov

  •   22 January (Monday, 10:00, room BB217)
    Prof. Barbara Hammer
    Technical University Clausthal, Germany
    Recent advances in clustering
    invited by: M. Biehl

    2006

  •   30 October (Monday, 15:30)
    talk postponed, new date to be announced

  •   23 October (Monday, 15:30)
    Dr. Anna Vilanova i Bartroli
    TU Eindhoven, Dept. of Biomedical Engineering
    Transfer functions in volume rendering
    invited by: Jos Roerdink

  •   25 September (Monday, 15:30) Zernikeborg, Room 17
    Juriaan Mulder, Marc Lausberg, Arjen Brinkman
    Personal Space Technologies
    Introduction and demonstration of a Desktop Virtual Reality Personal Space Station (with demo and hands-on experiments)
    invited by: Jos Roerdink

    (joint CS and Mathematics colloquium)
  •   26 June (Monday, 15:30)
    Herman te Riele
    CWI Amsterdam
    Factoring large numbers: easy or hard?
    invited by: Jaap Top

    The entire presentation (pdf) is available here

  •   22 June (Thursday, 11:00, room BB217)
    Ingrid Rewitzky
    University of Stellenbosch, South Africa
    Duality as a unifying framework for program semantics
    invited by: G. Renardel

  •   21 June (Wednesday, 16:00, room RC250)
    Vasile Palade
    University of Oxford
    Multi-Classifier Systems for Bioinformatics Problems
    invited by: N. Petkov

  •   24 April (Monday, 15:30)
    Marc Strickert
    Leibniz Inst. of Plant Genetics, Gatersleben/Germany
    New clustering and classification techniques for detecting gene expression patterns
    invited by: M. Biehl

  •   24 April (Monday, 13:30, WSN 35)
    Gerald Sommer
    University of Kiel, Germany
    Local analysis of multi-dimensional signals
    invited by: N. Petkov

  •   27 March (Monday, 15:30)
    Joost Batenburg
    Discrete Tumography and its applications
    invited by: J. Roerdink

  •   16 March (Thursday, 11:00, room t.b.a.)
    Jesper Andersson (Växjö University, Sweden)
    Software Quality Platforms

  •   27 February (Monday, 15:30)
    talk had to be postponed, new date t.b.a.
    Frederic Chazal (Dijon, France)
    invited by: G. Vegter

  •   20 February (changed!) (Monday, 15:30)
    Jean Serra (Fontainebleau, France)
    invited by: M. Wilkinson

  •   6 February no colloquium, reserved for "discipline overleg Informatica"

  •   27 January (Friday, room BB 210, 15:30)
    Ioannis Patras (York, UK)
    Recognition of body and facial gestures
    invited by: N. Petkov

  •   23 January (Monday, 15:30) Astrid Sturm, FU Berlin
    Approximation of an open polygonal curve with mininimal number of circular arcs (work in progress)
    invited by: G. Vegter

  •   16 January (Monday, 15:30)
    Jean-Bernard Martens (TU Eindhoven)
    Psychophysical measurement and modeling of human impressions
    invited by: J. Roerdink

    2005

  •   12 December (Monday, 15:30)
    Frits Post, TU Delft
    Visualization of Diffusion Tensor Imaging Data
    invited by: J. Roerdink

  •   5 December (Monday, 15:30)
    Th. Villmann, Univ. Leipzig
    Neural Maps and Learning Vector Quantization for Faithful Data Mining in Medical Data Analysis
    invited by: M. Biehl

  •   28 November (Monday)
    Lidia Sanchez, Univ. of Leon,
    Statistical approach to boar semen evaluation using intracellular intensity distribution of head images
    invited by: N. Petkov

  •   21 November (Monday, 15:30)
    Christian Wöhler (Daimler Chrysler Research, Ulm)
    A framework for image-based 3D scene reconstruction based on photometric, polarimetric, and real-aperture methods
    invited by: M. Biehl

  •   17 November (Thursday!)
    Andreas Dengel (Univ. Kaiserslautern)
    Knowledge Management: From Documents to Organization Memories
    invited by: N. Petkov

  •   14 November (Monday 11:00, room t.b.a.)
    W. Kropatsch (TU Wien)
    Hierarchies relating Topology and Geometry
    invited by: N. Petkov

  •   7 November (Monday 15:30)
    D. Reniers (TU Eindhoven)
    Feature Transforms and Their Applications to Skeletonization (preliminary title)
    invited by: J. Roerdink

  •   19 September (Monday, 15:30)
    Aleksandra Pizurica (University of Gent)
    Wavelet domain image and video denoising and applications in medical imaging
    invited by: J. Roerdink

  •   18 July (Monday, 2 talks)
    Reinhard Klette, Gisela Klette (University of Auckland)
    to be announced
    invited by: N. Petkov

  •   27 June 2005 (Monday, 15:30)
    Hugues Talbot, ESIEE Paris
    n-D globally minimal surfaces for segementation
    invited by: J. Roerdink

  •   20 June 2005 (Monday, 15:30) AIO colloqium
    to be announced

  •   1 June 2005 (Wednesday, 16:00, BB216)
    Emanuele Trucco, Heriot Watt University, Edinburgh
    3-D Computer Vision And Immersive Communications
    invited by: M. Wilkinson
  •   30 May 2005 (Monday, 15:30, room BB217)
    Meltem Ballan, AIO Colloquium
    A cognitive task and a basic EEG application
  •   23 May 2005 (Monday, 15:30, room BB217)
    Laurant Najman, ESIEE Paris,
    Topological Watershed Transform
    invited by: M. Wilkinson
  •   2 May 2005 (Monday, room BB210)
    AIO Colloqium: Ronald van den Berg
    Simultaneous colour search renders other object properties less noticeable
  •   26 April 2005 (Tuesday)
    Ian McDonald, Head of Computer Science Department, Otago University (New Zealand)
    Extracting useful information from free text medical data / Computer Science at the University of Otago
    invited by: G. Renardel
  •   25 April 2005 (Monday, Room BB 217)
    Marc Timme , MPI für Dynamik und Selbstorganisation, Göttingen,
    Precise Dynamics of Spiking Neural Networks - Unstable Attractors, Synchronization, and Natural Computation
    invited by: M. Biehl
  •   14 April 2005 (Thursday, Room ZG 7)
    M. Herlihy, Brown University, Computer Science
    The Transactional Manifesto: Toward a Low-Level API for Scalable Synchronization
    invited by: W. Hesselink
  •   11 April 2005 (Monday, Room ZG 7)
    D. Saad, Aston University, Neural Computing Research Group
    Getting the message across - the statistical physics of error-correcting codes
    invited by: M. Biehl
  •   21 March 2005 (Monday, Room RC 250) AIO colloqium
    Erik Urbach, Intelligent Systems
  •   21 February 2005 (monday) AIO colloqium
    S. Deelstra (Software Engineering)
    Variability Assessment for Evolving Software Product Families
  •   14 February 2005 (monday)
    Robert Urbanczik (Bern, Switzerland)
    Describing metabolic network conversion cones
    invited by: M. Biehl
  •   24 January 2005 (AIO Colloqium)
    G. Ouzounis (Intelligent Systems)
    Second Order Connected Attribute Filters
  •   10 January 2005 (monday)
    Michael Biehl (Intelligent Systems)
    The dynamics of Learning Vector Quantization
    invited by: M. Biehl :-)
  • 2004

  •   6 December (monday)
    Gyan Bhanot, IBM Research and IAS Princeton
    Robust meta-classification strategy for cancer detection from mass sprectroscopy data
    invited by: N. Petkov
  •   15 November (monday)
    Peter Riegler (Braunschweig/Wolfenbüttel)
    Maximum Entropy Sequential Sampling
    invited by: M. Biehl
  •   8 November (monday)
    Heiko Neumann (Ulm)
    Neural Models of Recurrent Processing in Form and Motion Perception
    invited by: N. Petkov
  •   11 October (monday)
    Peter Desain (Nijmegen):
    Detection of Perceived and Imagined Rhythm from single trial ERP
  •   4 October (monday)
    Gerrit van der Hoeven (Twente):
    The Computer Science Curriculum in Twente
    invited by: G. Renardel
  •   20 September (monday)
    Gerard Renardel (Groningen):
    Computing Science in Uganda
  •   13 September (monday)
    Luc Florack (Eindhoven)
    Geometrical models for early vision
    invited by: N. Petkov
  •   1 September (wednesday, room RC59, 16:00)
    Sanjit K. Mitra (UC Santa Barbara):
    Efficient nonlinear image processing algorithms
    invited by: N. Petkov