Petros Koumoutsakos

Dr. Petros Koumoutsakos

Computational Science, ETH Zurich, Clausiusstrasse 33, CLT, F12, CH-8092, Zurich, Switzerland
orcid

Research Focus & Metrics

Academic Career Length

40Years (1987-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2003 in Evolutionary Computation
Verified
Journal Article
Closed access
NHNikolaus Hansen
Nikolaus Hansen
SMSibylle D. Müller
Sibylle D. Müller
PKPetros Koumoutsakos
Petros Koumoutsakos
This paper presents a novel evolutionary optimization strategy based on the derandomized evolution strategy with covariance matrix adaptation (CMA-ES). This new approach is intended to reduce the number of generations required for convergence to the optimum. Reducing the number of generations, i.e., the time complexity of the algorithm, is important if a large population size is desired: (1) to reduce the effect of noise; (2) to improve global search properties; and (3) to implement the algorithm on (highly) parallel machines. Our method results in a highly parallel algorithm which scales favorably with large numbers of processors. This is accomplished by efficiently incorporating the available information from a large population, thus significantly reducing the number of generations needed to adapt the covariance matrix. The original version of the CMA-ES was designed to reliably adapt the covariance matrix in small populations but it cannot exploit large populations efficiently. Our modifications scale up the efficiency to population sizes of up to 10n, where n is the problem dimension. This method has been applied to a large number of test problems, demonstrating that in many cases the CMA-ES can be advanced from quadratic to linear time complexity.

1 August 2005 in Journal of Structural Biology
Verified
Journal Article
Closed access
ISI.F. Sbalzarini
I.F. Sbalzarini
PKPetros Koumoutsakos
Petros Koumoutsakos

16 January 2003 in The Journal of Physical Chemistry B
Verified
Journal Article
Closed access
TWT. Werder
T. Werder
JWJens Honore WALTHER
Jens Honore WALTHER
RJR. L. Jaffe
R. L. Jaffe
THT. Halicioglu
T. Halicioglu
PKPetros Koumoutsakos
Petros Koumoutsakos

6 May 2015 in eLife
Verified
Journal Article
Open access
PRPierre Barbier de Reuille
Pierre Barbier de Reuille
ARAnne-Lise Routier-Kierzkowska
Anne-Lise Routier-Kierzkowska
DKDaniel Kierzkowski
Daniel Kierzkowski
GBGeorge W Bassel
George W Bassel
TSThierry Schüpbach
Thierry Schüpbach
RSRichard S. Smith
Richard S. Smith
Morphogenesis emerges from complex multiscale interactions between genetic and mechanical processes. To understand these processes, the evolution of cell shape, proliferation and gene expression must be quantified. This quantification is usually performed either in full 3D, which is computationally expensive and technically challenging, or on 2D planar projections, which introduces geometrical artifacts on highly curved organs. Here we present MorphoGraphX (www.MorphoGraphX.org), a software that bridges this gap by working directly with curved surface images extracted from 3D data. In addition to traditional 3D image analysis, we have developed algorithms to operate on curved surfaces, such as cell segmentation, lineage tracking and fluorescence signal quantification. The software's modular design makes it easy to include existing libraries, or to implement new algorithms. Cell geometries extracted with MorphoGraphX can be exported and used as templates for simulation models, providing a powerful platform to investigate the interactions between shape, genes and growth.

25 April 2009 in BioTechniques
Verified
Journal Article
Open access
TGTobias Gebäck
Tobias Gebäck
MSMartin Michael Peter Schulz
Martin Michael Peter Schulz
PKPetros Koumoutsakos
Petros Koumoutsakos
MDMichael Detmar
Michael Detmar
Cell migration plays a major role in development, physiology, and disease, and is frequently evaluated in vitro by the monolayer wound healing assay. The assay analysis, however, is a time-consuming task that is often performed manually. In order to accelerate this analysis, we have developed TScratch, a new, freely available image analysis technique and associated software tool that uses the fast discrete curvelet transform to automate the measurement of the area occupied by cells in the images. This tool helps to significantly reduce the time needed for analysis and enables objective and reproducible quantification of assays. The software also offers a graphical user interface which allows easy inspection of analysis results and, if desired, manual modification of analysis parameters. The automated analysis was validated by comparing its results with manual-analysis results for a range of different cell lines. The comparisons demonstrate a close agreement for the vast majority of images that were examined and indicate that the present computational tool can reproduce statistically significant results in experiments with well-known cell migration inhibitors and enhancers.