3 Search Results for "Hofmann, Andreas G."

Document
DOI: 10.4230/DagSemProc.10081.8
Exploiting Spatial and Temporal Flexibility for Exploiting Spatial and Temporal Flexibility for Plan Execution of Hybrid, Under-actuated Systems

Authors: Andreas G. Hofmann and Brian C. Williams

Published in: Dagstuhl Seminar Proceedings, Volume 10081, Cognitive Robotics (2010)

Abstract
Robotic devices, such as rovers and autonomous spacecraft, have been successfully controlled by plan execution systems that use plans with temporal flexibility to dynamically adapt to temporal disturbances. To date these execution systems apply to discrete systems that abstract away the detailed dynamic constraints of the controlled device. To control dynamic, under-actuated devices, such as agile bipedal walking machines, we extend this execution paradigm to incorporate detailed dynamic constraints. Building upon prior work on dispatchable plan execution, we introduce a novel approach to flexible plan execution of hybrid under-actuated systems that achieves robustness by exploiting spatial as well as temporal plan flexibility. To accomplish this, we first transform the high-dimensional system into a set of low dimensional, weakly coupled systems. Second, to coordinate these systems such that they achieve the plan in real-time, we compile a plan into a concurrent timed flow tube description. This description represents all feasible control trajectories and their temporal coordination constraints, such that each trajectory satisfies all plan and dynamic constraints. Finally, the problem of runtime plan dispatching is reduced to maintaining state trajectories in their associated flow tubes, while satisfying the coordination constraints. This is accomplished through an efficient local search algorithm that adjusts a small number of control parameters in real-time. The first step has been published previously; this paper focuses on the last two steps. The approach is validated on the execution of a set of bipedal walking plans, using a high fidelity simulation of a biped.
Cite as

Andreas G. Hofmann and Brian C. Williams. Exploiting Spatial and Temporal Flexibility for Exploiting Spatial and Temporal Flexibility for Plan Execution of Hybrid, Under-actuated Systems. In Cognitive Robotics. Dagstuhl Seminar Proceedings, Volume 10081, pp. 1-8, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2010)

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@InProceedings{hofmann_et_al:DagSemProc.10081.8,
  author =	{Hofmann, Andreas G. and Williams, Brian C.},
  title =	{{Exploiting Spatial and Temporal Flexibility for Exploiting Spatial and Temporal Flexibility for Plan Execution of Hybrid, Under-actuated Systems}},
  booktitle =	{Cognitive Robotics},
  pages =	{1--8},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2010},
  volume =	{10081},
  editor =	{Gerhard Lakemeyer and Hector J. Levesque and Fiora Pirri},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.10081.8},
  URN =		{urn:nbn:de:0030-drops-27740},
  doi =		{10.4230/DagSemProc.10081.8},
  annote =	{Keywords: }
}
Document
DOI: 10.4230/DagSemProc.08141.4
A Virtual Layer for FPGA Based Parallel Systems (MP-SoCs)

Authors: Andreas Hofmann and Klaus Waldschmidt

Published in: Dagstuhl Seminar Proceedings, Volume 8141, Organic Computing - Controlled Self-organization (2008)

Abstract
Besides performance and time to market, robustness and reliability are important design targets for modern Systemson- Chip (SoCs). Despite these features the power consumption must be as low as possible. To meet these design goals parallel, flexible, and adaptive architectures are required [1]. Today, dynamically reconfigurable FPGAs are well suited to form a parallel architecture because they incorporate serveral hard- and softcores. To efficiently use such multicore systems a hardware independent system must be created which handles all cores. Further, optimizing the power management the number of active cores must be adapted dynamically to the current workload. To make these features manageable and augment the system with adaptivity a virtual layer is required which hides the – due to runtime reconfiguration – changing hardware system from the application software. The Scalable Dataflow-driven Virtual Machine [2] is such a virtualization of a parallel, adaptive and heterogeneous cluster of processing elements (PE). Thus, it is well suited to serve as a managing firmware for multicore FPGAs.
Cite as

Andreas Hofmann and Klaus Waldschmidt. A Virtual Layer for FPGA Based Parallel Systems (MP-SoCs). In Organic Computing - Controlled Self-organization. Dagstuhl Seminar Proceedings, Volume 8141, pp. 1-2, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2008)

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@InProceedings{hofmann_et_al:DagSemProc.08141.4,
  author =	{Hofmann, Andreas and Waldschmidt, Klaus},
  title =	{{A Virtual Layer for FPGA Based Parallel Systems (MP-SoCs)}},
  booktitle =	{Organic Computing - Controlled Self-organization},
  pages =	{1--2},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2008},
  volume =	{8141},
  editor =	{Kirstie Bellman and Michael G. Hinchey and Christian M\"{u}ller-Schloer and Hartmut Schmeck and Rolf W\"{u}rtz},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.08141.4},
  URN =		{urn:nbn:de:0030-drops-15610},
  doi =		{10.4230/DagSemProc.08141.4},
  annote =	{Keywords: }
}
Document
DOI: 10.4230/DagSemProc.05471.8
Glycosylation Patterns of Proteins Studied by Liquid Chromatography-Mass Spectrometry and Bioinformatic Tools

Authors: Hansjörg Toll, Peter Berger, Andreas Hofmann, Andreas Hildebrandt, Herbert Oberacher, Hans Peter Lenhof, and Christian G. Huber

Published in: Dagstuhl Seminar Proceedings, Volume 5471, Computational Proteomics (2006)

Abstract
Due to their extensive structural heterogeneity, the elucidation of glycosylation patterns in glycoproteins such as the subunits of chorionic gonadotropin (CG), CG-alpha and CG-beta remains one of the most challenging problems in the proteomic analysis of posttranslational modifications. In consequence, glycosylation is usually studied after decomposition of the intact proteins to the proteolytic peptide level. However, by this approach all information about the combination of the different glycopeptides in the intact protein is lost. In this study we have, therefore, attempted to combine the results of glycan identification after tryptic digestion with molecular mass measurements on the intact glycoproteins. Despite the extremely high number of possible combinations of the glycans identified in the tryptic peptides by high-performance liquid chromatography-mass spectrometry (> 1000 for CG-alpha and > 10.000 for CG-beta), the mass spectra of intact CG-alpha and CG-beta revealed only a limited number of glycoforms present in CG preparations from pools of pregnancy urines. Peak annotations for CG-alpha were performed with the help of an algorithm that generates a database containing all possible modifications of the proteins (inclusive possible artificial modifications such as oxidation or truncation) and subsequent searches for combinations fitting the mass difference between the polypeptide backbone and the measured molecular masses. Fourteen different glycoforms of CG-alpha, including methionine-oxidized and N-terminally truncated forms, were readily identified. For CG-beta, however, the relatively high mass accuracy of ± 2 Da was still insufficient to unambiguously assign the possible combinations of posttranslational modifications. Finally, the mass spectrometric fingerprints of the intact molecules were shown to be very useful for the characterization of glycosylation patterns in different CG preparations.
Cite as

Hansjörg Toll, Peter Berger, Andreas Hofmann, Andreas Hildebrandt, Herbert Oberacher, Hans Peter Lenhof, and Christian G. Huber. Glycosylation Patterns of Proteins Studied by Liquid Chromatography-Mass Spectrometry and Bioinformatic Tools. In Computational Proteomics. Dagstuhl Seminar Proceedings, Volume 5471, pp. 1-6, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2006)

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@InProceedings{toll_et_al:DagSemProc.05471.8,
  author =	{Toll, Hansj\"{o}rg and Berger, Peter and Hofmann, Andreas and Hildebrandt, Andreas and Oberacher, Herbert and Lenhof, Hans Peter and Huber, Christian G.},
  title =	{{Glycosylation Patterns of Proteins Studied by Liquid Chromatography-Mass Spectrometry and Bioinformatic Tools}},
  booktitle =	{Computational Proteomics},
  pages =	{1--6},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2006},
  volume =	{5471},
  editor =	{Christian G. Huber and Oliver Kohlbacher and Knut Reinert},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.05471.8},
  URN =		{urn:nbn:de:0030-drops-5431},
  doi =		{10.4230/DagSemProc.05471.8},
  annote =	{Keywords: Liquid chromatography, mass spectrometry, glycoproteins, glycosylation, peak annotation}
}
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