Waldminghaus T.,University of Oslo |
Waldminghaus T.,University of Marburg |
Weigel C.,HTW Berlin University of Applied Sciences |
Skarstad K.,University of Oslo
Nucleic Acids Research | Year: 2012
In Escherichia coli, the SeqA protein binds specifically to GATC sequences which are methylated on the A of the old strand but not on the new strand. Such hemimethylated DNA is produced by progression of the replication forks and lasts until Dam methyltransferase methylates the new strand. It is therefore believed that a region of hemimethylated DNA covered by SeqA follows the replication fork. We show that this is, indeed, the case by using global ChIP on Chip analysis of SeqA in cells synchronized regarding DNA replication. To assess hemimethylation, we developed the first genome-wide method for methylation analysis in bacteria. Since loss of the SeqA protein affects growth rate only during rapid growth when cells contain multiple replication forks, a comparison of rapid and slow growth was performed. In cells with six replication forks per chromosome, the two old forks were found to bind surprisingly little SeqA protein. Cell cycle analysis showed that loss of SeqA from the old forks did not occur at initiation of the new forks, but instead occurs at a time point coinciding with the end of SeqA-dependent origin sequestration. The finding suggests simultaneous origin de-sequestration and loss of SeqA from old replication forks. © The Author(s) 2012. Published by Oxford University Press.
Mutterer J.,French National Center for Scientific Research |
Zinck E.,HTW Berlin University of Applied Sciences
Journal of Microscopy | Year: 2013
We created FigureJ a new ImageJ plugin dedicated to scientific article figures preparation. Building a convincing figure is a demanding task that covers different steps ranging from content acquisition to figure assembly in editing software. Notions of image processing are required when it comes to even simple tasks such as cropping or resizing images and assembling them in a single figure. Scientific images are typically well handled in dedicated software but poorly supported in software used for laying out the final version of a figure for submission to review process. © 2013 Royal Microscopical Society.
Jung K.,HTW Berlin University of Applied Sciences
IEEE International Conference on Consumer Electronics - Berlin, ICCE-Berlin | Year: 2012
An image classification approach is presented that uses a combination of low-level image features with features obtained from interest point detection. A support vector machine is used for classification. The approach focuses on the recognition of three-dimensional objects captured with the camera of a smartphone under different perspectives. Recognition as well as the training of new objects can be performed by the smartphone within reasonable processing time. © 2012 IEEE.
Bailleu A.,HTW Berlin University of Applied Sciences
SAS 2016 - Sensors Applications Symposium, Proceedings | Year: 2016
The positions of the ultrasonic transducers of clamp-on flowmeters have a determining influence on the precision and the accuracy of the measurement results. In this paper a transducer positioning system for ultrasonic clamp-on sensor applications is presented. It was designed in result of studies of the sensitivity and works automatically. The positioning system found an optimal transducer position for a special application by itself. So, the user can operate the clamp-on flowmeter with neither finding out some special information of the application process nor setting any parameters in the system before. © 2016 IEEE.
Schulte H.,HTW Berlin University of Applied Sciences |
Georg S.,HTW Berlin University of Applied Sciences
Journal of Physics: Conference Series | Year: 2014
A nonlinear model-based control concept for wind turbines with hydrostatic transmission is proposed. The complete mathematical model of a wind turbine drive train with variable displacement pump and variable displacement motor is presented. The controller design takes into consideration the nonlinearity of the aerodynamic maps and hydrostatic drive train by an convex combination of state space controller with measurable generator speed and hydraulic motor displacement as scheduling parameters. The objectives are the set point control of generator speed and tracking control of the rotor speed to reach the maximum power according to the power curve in the partial-load region. © Published under licence by IOP Publishing Ltd.
Porschen S.,HTW Berlin University of Applied Sciences
IMECS 2011 - International MultiConference of Engineers and Computer Scientists 2011 | Year: 2011
We consider a specific class of combinatorial search or optimization problems where the search space gives rise to a closure operator and essentially the hulls are the only relevant subsets that must be checked in a brute force approach. We suggest that such a closure property can help to reduce time complexities. Moreover we propose two types of (structural) parameterization of instance classes based on the closure property and outline how it could be used to achieve FPT characterizations. In this setting, three example problems are considered: a covering problem from combinatorial geometry, a variant of the autarky problem in propositional logic, and a specific graph problem on finite forests.
Kraume M.,TU Berlin |
Drews A.,HTW Berlin University of Applied Sciences
Chemical Engineering and Technology | Year: 2010
Due to their unique advantages like controlled biomass retention, improved effluent quality, and decreased footprint, membrane bioreactors (MBRs) are being increasingly used in waste water treatment up to a capacity of several 100,000 p.e. This article reviews the current status of MBRs and reports trends in MBR design and operation. Typical operational and design parameters are given as well as guidelines for waste water treatment plant revamping. To further improve the biological performance, specific or hybrid process configurations are shown to lead to, e.g., enhanced nutrient removal. With regards to reducing membrane fouling, optimized modules, advanced control, and strategies like the addition of flux enhancers are currently emerging. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Baar T.,HTW Berlin University of Applied Sciences
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016
A Domain-Specific Language (DSL) allows the succinct modeling of phenomena in a problem domain. Modern DSL-tools make it easy for a language designer to define the syntax of a new DSL, to specify code generators or to build a new DSL on top of existing DSLs. Based on the language specification, the DSL-tool then generates rich editors. Often, these editors support features such as syntax highlighting, code completion or automatic refactoring. In this paper, we describe an approach of adding verification support for DSLs defined within the Eclipse-framework Xtext. Xtext provides good support for checking the well-formedness rules of the DSL’s syntax. In contrast, support for specifying the language’s semantics as well as verification support have been rather neglected so far. Our approach of incorporating semantic verification techniques is illustrated by a very simple State-Transition-DSL, which has been fully implemented in Xtext. The DSL’s editor verifies on the fly that the current model holds some semantic properties such as deterministic execution and invariant preservation. The verification services for this DSL are based on the theorem prover PRINCESS. © Springer International Publishing Switzerland 2016.
Porschen S.,HTW Berlin University of Applied Sciences
Lecture Notes in Engineering and Computer Science | Year: 2016
Some structural aspects in the area of propositional satisfiability of CNF formulas are discussed. We consider decompositions of formulas and introduce a decomposition of the class of unsatisfiable formulas. Further we investigate specific base hyper- graphs of formulas recalling the fibre perspective.
Bohm L.,TU Berlin |
Drews A.,HTW Berlin University of Applied Sciences |
Kraume M.,TU Berlin
Journal of Membrane Science | Year: 2013
With regard to the improvement of the cleaning process of flat sheet membrane modules by aeration, a statistical analysis of the shear stress generated by single bubbles is shown for 21 different parameter combinations of varied channel depths, bubble sizes and liquid velocities. A fully automated rig allowed the generation of a sufficient database of shear stress data gained with the electrodiffusion method (EDM). The maximum shear stresses and the global shear stress levels, where the latter represents the global shear stress fluctuations, were determined. To the authors' knowledge, for the first time in membrane research a transient correction of the EDM data was performed which is necessary in cases of highly transient processes. By showing different probability ranges gained from cumulative distribution functions in bar plots, a way of presenting the data was introduced that simplifies the comparison between the different geometrical and operating parameter combinations. Additionally, this type of diagram offers a very comprehensive overview of the measured data. Both the maximum shear stress and the global shear stress levels are larger when the bubble is larger than the channel depth and when an additional liquid velocity is superimposed. In all cases, the transient correction yielded higher values. Thus it is necessary to take this measure.In the investigated range, the highest maximum values were obtained for the case with superimposed liquid velocity, a channel depth of 5. mm and a bubble size of 9. mm with appr. 1.3. Pa (steady analysis) or 4.7. Pa (transient corrected analysis), respectively. The largest fluctuation ranges of the global shear stress levels were obtained for a channel depth of 5. mm and a bubble size of 9. mm with values from appr. 0.2 to 1.1. Pa (steady analysis) or 0 to 2.6. Pa (transient corrected analysis). © 2013 Elsevier B.V.