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ERROR REDUCTION IN ADAPTIVE FINITE ELEMENT APPROXIMATIONS OF ELLIPTIC OBSTACLE PROBLEMS

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Journal of Computational Mathematics 2009年第2期27卷 148-169页

作者： Dietrich Braess carsten carstensen Ronald H.W.Hoppe Faculty of Mathematics Ruhr University BochumD-44780 BochumGermany Institute of Mathematics Humboldt University of BerlinD-10099 BerlinGermany Department of Mathematics University of HoustonHoustonTX 77204-3008USA Institute of Mathematics University at AugsburgD-86159 AugsburgGermany

We consider an adaptive finite element method （AFEM） for obstacle problems associated with linear second order elliptic boundary value problems and prove a reduction in the energy norm of the discretization error which leads to R-linear convergence. This result is shown to hold up to a consistency error due to the extension of the discrete multipliers （point functionals） to H^-1 and a possible mismatch between the continuous and discrete coincidence and noncoincidence sets. The AFEM is based on a residual-type error estimator consisting of element and edge residuals. The a posteriori error analysis reveals that the significant difference to the unconstrained case lies in the fact that these residuals only have to be taken into account within the discrete noncoincidence set. The proof of the error reduction property uses the reliability and the discrete local efficiency of the estimator as well as a perturbed Galerkin orthogonality. Numerical results are given illustrating the performance of the AFEM.

关键词： Adaptive finite element methods Elliptic obstacle problems Convergence analysis

Forensic Readiness: Emerging Discipline for Creating Reliable and Secure Digital Evidence

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Journal of Harbin Institute of Technology(New Series) 2015年第1期22卷 1-8页

作者： Barbara Endicott-Popovsky Nicolai Kuntze carsten Rudolph Institute of Technology University of Washington Fraunhofer Institute of Technology

Traditional approaches to digital forensics reconstruct events within digital systems that often are not built for the creation of evidence; however,there is an emerging discipline of forensic readiness that examines what it takes to build systems and devices that produce digital data records for which admissibility is a requirement. This paper reviews the motivation behind research in this area,a generic technical solution that uses hardware-based security to bind digital records to a particular state of a device and proposed applications of this solution in concrete,practical scenarios. Research history in this area,the notion of secure digital evidence and a technical solution are discussed. A solution to creating hardware-based security in devices producing digital evidence was proposed in 2012. Additionally,this paper revises the proposal and discusses three distinct scenarios where forensic readiness of devices and secure digital evidence are relevant. It shows,how the different requirements of the three scenarios can be realized using a hardware-based solution. The scenarios are:lawful interception of voice communication,automotive black box,precise farming. These three scenarios come from very distinctive application domains. Nevertheless,they share a common set of security requirements for processes to be documented and data records to be stored.

关键词： digital forensics forensic readiness calibration d

Continuous size fractionation of magnetic nanoparticles by using simulated moving bed chromatography

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Frontiers of Chemical Science and Engineering 2021年第5期15卷 1346-1355页

作者： carsten-Rene Arlt Dominik Brekel Stefan Neumann David Rafaja Matthias Franzreb Institute of Functional Interfaces Karlsruhe Institute of Technology76344Eggenstein-LeopoldshafenKarlsruheGermany Institute of Materials Science TU Bergakademie Freiberg09599FreibergGermany

The size fractionation of magnetic nanoparticles is a technical problem,which until today can only be solved with great ***,there is an important demand for nanoparticles with sharp size distributions,for example for medical technology or sensor *** magnetic chromatography,we show a promising method for fractionation of magnetic nanoparticles with respect to their size and/or magnetic *** was achieved by passing magnetic nanoparticles through a packed bed of fine steel spheres with which they interact magnetically because single domain ferro-/ferrimagnetic nanoparticles show a spontaneous *** the strength of this interaction is related to particle size,the principle is suitable for size *** concept was transferred into a continuous process in this work using a so-called simulated moving bed *** a suspension of magnetic nanoparticles within a size range from 20 to 120 nm,the process showed a separation sharpness of up to 0.52 with recovery rates of 100%.The continuous feed stream of magnetic nanoparticles could be fractionated with a space-time-yield of up to 5 mg/(L∙min).Due to the easy scalability of continuous chromatography,the process is a promising approach for the efficient fractionation of industrially relevant amounts of magnetic nanoparticles.

关键词： magnetic chromatography simulated moving bed chromatography magnetic nanoparticles size fractionation

i2dash:Creation of Flexible,Interactive,and Web-based Dashboards for Visualization of Omics Data

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Genomics, Proteomics & Bioinformatics 2022年第3期20卷 568-577页

作者： Arsenij Ustjanzew Jens Preussner Mette Bentsen carsten Kuenne Mario Looso Max Planck Institute for Heart and Lung Research Bioinformatics UnitD-61231 Bad NauheimGermany

Data visualization and interactive data exploration are important aspects of illustrating complex concepts and results from analyses of omics data.A suitable visualization has to be intuitive and ***-based dashboards have become popular tools for the arrangement,consolidation,and display of such ***,the combination of automated data processing pipelines handling omics data and dynamically generated,interactive dashboards is poorly ***,we present i2dash,an R package intended to encapsulate functionality for the programmatic creation of customized *** supports interactive and responsive(linked)visualizations across a set of predefined graphical layouts.i2dash addresses the needs of data analysts/software developers for a tool that is compatible and attachable to any R-based analysis pipeline,thereby fostering the separation of data visualization on one hand and data analysis tasks on the other *** addition,the generic design of i2dash enables the development of modular extensions for specific *** a proof of principle,we provide an extension of i2dash optimized for single-cell RNA sequencing analysis,supporting the creation of dashboards for the visualization needs of such *** with these features,i2dash is suitable for extensive use in large-scale sequencing/bioinformatics *** this line,we provide i2dash as a containerized solution,enabling a straightforward large-scale deployment and sharing of dashboards using cloud services.i2dash is freely available via the R package archive CRAN(https://***/package=i2dash).

关键词： Data visualization Dashboard Cloud Data analysis Automation

Difference in formation of plasma electrolytic oxidation coatings on MgLi alloy in comparison with pure Mg

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Journal of Magnesium and Alloys 2021年第5期9卷 1745-1760页

作者： Ting Wu carsten Blawert Xiaopeng Lu Maria Serdechnova Mikhail L.Zheludkevich Institute of Surface Science Helmholtz-Zentrum Hereon21502 GeesthachtGermany Shenyang National Laboratory for Materials Science Northeastern University110819 ShenyangChina Institute for Materials Science Faculty of EngineeringKiel UniversityKaiserstrasse 224143 KielGermany

In order to study the substrate lattice structure(Li addition)on the growth of plasma electrolytic oxidation(peO)coatings,Mg Li alloy(11.36 wt.%of Li,cubic)and pure Mg(hexagonal)were treated under a pulsed direct peO mode in a phosphate electrolyte for different periods of *** results revealed that the presence of Li and Li-rich phases in the cubic Mg alloy seems to be essential for the treatment result rather than the original lattice structure.A modified discharge behavior of Mg Li alloy finally led to a different microstructure of the *** unstable coatings of Mg Li alloy tended to dissolve rapidly though shared the similar composition to that of pure *** was incorporated only in the primary conversion products at the interface of coating/Mg *** spite of the advanced efficiency of energy input during processing,the more porous and thinner peO coatings on the Mg Li alloy were less resistant to abrasion and corrosion.

关键词： Plasma electrolytic oxidation Magnesium lithium alloy Pure magnesium Microstructure

Coating performance on glutaraldehyde-modified wood

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Journal of Forestry Research 2019年第1期30卷 353-361页

作者： Zefang Xiao Haiou Chen carsten Mai Holger Militz Yanjun Xie Key Laboratory of Bio-based Material Science and Technology (Ministry of Education) Northeast Forestry University Wood Biology and Wood Products Burckhardt–InstituteGeorg August University of G?ttingen

Scots pine(Pinus sylvestris L.) panels were modified with glutaraldehyde(GA) to various weight percent gains and subsequently coated with several commercial coatings. The drying rate and adhesion of the coatings on the modified wood were measured; the coated/modified woods were exposed outdoors to analyze how the wood modifications influence the coating deterioration. The results showed that GA modification caused an increase in the drying rate of the waterborne coatings, but had no influence on drying of tested solvent-borne coatings. GAmodification did not change the dry adhesion but reduced the wood strength in a pull-off test. Wet adhesion of waterborne coatings was improved, while that of the solvent-borne coatings tended to be somewhat reduced. During 22 months of outdoor weathering, the coated/modified samples exhibited lower moisture content than the coated/unmodified samples, but GA modification didn't contribute a substantially synergistic effect with surface coatings on resistance to weathering.

关键词： Chemical modification Glutaraldehyde Coating Adhesion Weathering

Optical Design of Multilayer Achromatic Waveplate by Simulated Annealing Algorithm

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Chinese Journal of Astronomy and Astrophysics 2008年第3期8卷 349-361页

作者： Jun Ma Jing-Shan Wang carsten Denker Hai-Min Wang Big Bear Solar Observatory 40386 North Shore Lane Big Bear City CA 92314 USA New Jersey Institute of Technology Center for Solar-Terrestrial Research 323 Martin Luther Kind Blvd. Newark NJ 07102 USA Astrophysikalisches Institut Potsdam An der Sternwarte 16 D- 14482 Potsdam Germany Currently working at Thorlabs Inc. 435 Route 206 Newton NJ 07860 USA

We applied a Monte Carlo method -- simulated annealing algorithm -- to carry out the design of multilayer achromatic waveplate. We present solutions for three-, six- and ten-layer achromatic waveplates. The optimized retardance settings are found to be 89°51′39″ ± 0°33′37″ and 89°54′46″ ± 0°22′4″ for the six- and ten-layer waveplates, respectively, for a wavelength range from 1000 nm to 1800 nm. The polarimetric properties of multilayer waveplates are investigated based on several numerical experiments. In contrast to previously proposed three-layer achromatic waveplate, the fast axes of the new six- and ten-layer achromatic waveplate remain at fixed angles, independent of the wavelength. Two applications of multilayer achromatic waveplate are discussed, the general-purpose phase shifter and the birefringent filter in the Infrared Imaging Magnetograph （IRIM） system of the Big Bear Solar Observatory （BBSO）. We also checked an experimental method to measure the retardance of waveplates.

关键词： instrumentation spectrographs -- methods numerical -- methods laboratory-- Sun infrared

Lithocholic acid induction of the FGF19 promoter in intestinal cells is mediated by PXR

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World Journal of Gastroenterology 2007年第31期13卷 4230-4235页

作者： Wolfgang Wistuba carsten Gnewuch Gerhard Liebisch Gerd Schmitz Thomas Langmann Institute of Clinical Chemistry and Laboratory Medicine University of Regensburg Regensburg 93053 Germany

To study the effect of the toxic secondary bile acid lithocholic acid （LCA） on the expression of fibroblast growth factor 19 （FGF19） in intestinal cells and to characterize the pregnane-X-receptor （PXR） response of the FGF19 promoter region. METHODS： The intestinal cell line LS174T was stimulated with various concentrations of chenodeoxy- cholic acid and lithocholic acid for several time points. FGF19 mRNA levels were determined with quantitative realtime RT-PCR. FGF19 deletion promoter constructs were generated and the LCA response was analzyed in reporter assays. Co-transfections with PXR and RXR were carried out to study FGF19 regulation by these factors, RESULTS： LCA and CDCA strongly up-regulate FGF19 mRNA expression in LS174T cells in a time and dose dependent manner. Using reporter gene assays with several deletion constructs we found that the LCA responsive element in the human FGF19 promoter maps to the proximal regulatory region containing two poten- tial binding sites for PXR. Overexpression of PXR and its dimerization partner retinoid X receptor （RXR） and stimulation with LCA or the potent PXR ligand rifampicin leads to a significant induction of FGF19 promoter activ- ity in intestinal cells. CONCLUSION： LCA induced feedback inhibition of bile acid synthesis in the liver is likely to be regulated by PXR inducing intestinal FGF19 expression.

关键词： Pregnane X receptor Detoxification Fibroblast growth factor 19 Lithocholic acid

An arctic low-energy house as experimental setup for studies of heat dynamics of buildings

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Frontiers of Architectural Research 2013年第4期2卷 488-499页

作者： Philip Delft Andersen carsten Rode Henrik Madsen DTU Compute Richard Pedersens Plads Technical University of Denmark Building 322 Kongens Lyngyb DK-2800 Denmark DTU Civil Engineering Brovej Bygning 118 Technical University of Denmark Kongens Lyngyb DK-2800 Denmark

This paper addresses the difficulties in pinpointing reasons for unexpectedly high energy consumption in construction, and in low-energy houses especially. Statistical methods are applied to improve the insight into the energy performance and heat dynamics of a building based on consumption records and weather data. Dynamical methods separate influences from outdoor temperature, solar radiation, and wind on the energy consumption in the building. The studied building is a low-energy house in Sisimiut, GreenLand. Weather conditions like large temperature differences between indoors and outdoors throughout tong winters, strong winds, and very different circumstances regarding solar radiation compared to areas where Low-energy houses are usually built, make the Location very interesting for modeling and testing purposes. In 2011 new measurement equipment was installed in the house, which will be used to develop more detailed models of the heat dynamics and energy performance in relation to different meteoroLogicaL variables, heating systems, and user behavior. This type of models is known as a graybox model and is been introduced in this paper.

关键词： Low-energy houses Heat dynamics Arctic climate Statistical modeling Graybox modeling