2,032 Works

„How we bec[o]me metadata“ : Beschreiben, Finden, Weitergeben und Verändern von Open Educational Resources (OER)

Thomas Hapke
Metadaten beeinflussen die Qualität des Findens und Nutzens von Open Educational Resources (OER). Aufgrund der Vielfalt der medialen Formate und inhaltlichen Komponenten von OER mit ihrer spezifischen Granularität und ihren Möglichkeiten zum Weiternutzen und Verändern steht die Integration von Metadaten in Informations-Infrastrukturen für OER vor spezifischen Herausforderungen. OER-Metadaten enthalten optimalerweise neben allgemeinen, beschreibenden Elementen auch Daten zu technischen, pädagogischen und rechtlichen Randbedingungen der Nutzung. Gleichzeitig muss die Praktikabilität der Metadaten-Erfassung und -Weitergabe berücksichtigt werden, um...

Pelvic girdle reconstruction based on spinal fusion and ischial screw fixation in a case of aneurysmal bone cyst

Matthias Honl, Florian Westphal, Volker Carrero, Michael Morlock, Karsten Schwieger, Ekkehard Hille & Günter Delling
A case of lytic lesion of the pelvis in a 23-year-old woman is presented. A biopsy led to the diagnosis aneurysmal bone cyst(ABC). Due to the histologically very aggressive growth of the tumor, a low malignant osteosarcoma could not be excluded.In an initial operation the tumour, affecting the sacrum, the iliac crest and the lower lumbar spine was resected. Temporaryrestabilisation of the pelvic ring was achieved by a titanium plate. The histological examination of the...

Treatment of dredged sludge for demobilization of pollutants, including development of methods for assessing its efficiency

Reza Khorasani, Wolfgang Calmano & Ulrich Förstner
Highly contaminated dredged harbour sludge has been mixed with lime, calcium carbonate, gypsum, waste kiln dust, cement, coal fly ash, and red mud for mechanical and/or chemical stabilization. Analyzing the products by electron microscope, microprobe and chemical extraction methods indicate, that new mineral formations fill the pores and stabilize the material. Heavy metals are incorporated into carbonates, sulfates and hydroxides; they show a shift in their phase specific bonding, but not always towards stronger fixation...

LPV control of a 2-DOF robot using parameter reduction

Andreas Kwiatkowski & Herbert Werner
This paper demonstrates the benefit of a new method for reducing the number of scheduling parameters of LPV controllers, by applying it to a robot manipulator. A full LPV representation of a planar two-link robot with ten scheduling parameters is considered. The number of parameters can be reduced by applying principal components analysis to typical scheduling trajectories. The proposed method enables a systematic trade-off between the number of reduced parameters and the desired accuracy of...

Information optimum design of discrete LDPC decoders for irregular codes

Maximilian Stark
Powerful forward error correction is inevitable for every modern communication system. However, leveraging all error correction capabilities offered by channel codes like low density parity check (LDPC) codes, introduces the burden of computationally demanding decoding at the receiver. Especially in power or latency restricted scenarios, efficient decoding algorithms are of crucial importance. In this thesis a novel decoding approach combining ideas from information theory and machine learning was developed, resulting in a so-called information-optimum LDPC...

Optimization of a composite latent heat storage (CLHS) with non-uniform heat fluxes using a genetic algorithm

Henrik Veelken & Gerhard Schmitz
The scope of this work is to show optimization potential for regularly structured composite latent heat storage (CLHS) devices with non-uniform heat loads by varying the distribution of fins on the contact surface to an electronic component. The modeling of the CLHS is carried out in 2D using Matlab in combination with Comsol and the effective heat capacity method for the melting process. The link between Matlab and Comsol is carried out with the Comsol–Matlab...

Über Grundlagen für den mathematischen Linienriß eines Frachtschiffes

Hans Thieme
Über Grundlagen für den mathematischen Linienriß eines Frachtschiffes

Chemical mobility and bioavailability of sediment-bound heavy metals influenced by salinity

Wolfgang Calmano, Wolfgang Ahlf & Jan-Christian Bening
The transfer of metals from contaminated sediments to algal cell walls (Scenedesmus quadricauda) and organisms from various trophic levels (euryhaline osmoconform hydroid Cordylophora caspia and algae Brachiomonas submarina) was studied with a multichamber device. The system consists of a central chamber which contained the mud suspension and six external chambers containing the different biological indicators. The solids in the central and external chambers are separated by 0.45 µm-diameter membranes which allow diffusion of the mobilized,...

Finite volume schemes for multi-dimensional hyperbolic systems based on the use of bicharacteristics

Mária Medviďová-Lukáčová & Jitka Saibertova
In this paper we present recent results for the bicharacteristic based finite volume schemes, the so-called finite volume evolution Galerkin (FVEG) schemes. These methods were proposed to solve multi-dimensional hyperbolic conservation laws. They combine the usually conflicting design objectives of using the conservation form and following the characteristics, or bicharacteristics. This is realized by combining the finite volume formulation with approximate evolution operators, which use bicharacteristics of multi-dimensional hyperbolic system. In this way all of...

High-energy X-rays : a tool for advanced bulk investigations in materials science and physics

Klaus-Dieter Liss, Arno Bartels, Andreas Schreyer & Helmut Clemens
The combination of these techniques is a strong issue for the construction and development of futureinstruments.

Computational model of gastric motility with active-strain electromechanics

Sebastian Brandstäter, Alessio Gizzi, Sebastian L. Fuchs, Amadeus M. Gebauer, Roland Aydin & Christian J. Cyron
We present an electro-mechanical constitutive framework for the modeling of gastric motility, including pacemaker electrophysiology and smooth muscle contractility. In this framework, we adopt a phenomenological description of the gastric tissue. Tissue electrophysiology is represented by a set of two minimal two-variable models and tissue electromechanics by an active-strain finite elasticity approach. We numerically investigate the implication of the spatial distribution of pacemaker cells on the entrainment and synchronization of the slow waves characterizing gastric...

The temperatures distributions of a single-disc clutches using heat partitioning and total heat generated approaches

Oday Ibraheem Abdullah, Josef Schlattmann, Mahir H. Majeed & Laith Abed Sabri
An accurate estimation of temperature distribution is considered necessary to avoid the premature failure of friction clutches. In this work, different approaches were used to compute the surface temperatures of the friction clutch disc. The results presented the maximum surface temperature when the contact occurs between the rubbing surfaces during a single engagement and repeated engagements. Two approaches were used to simulate the thermal models of the automotive clutches to obtain the temperature field are...

Evolutionary-based design and control of geometry aims for AMD-manufacturing of Ti-6Al-4V parts

Mauritz Möller, Nicolaj Baramsky, Ake Ewald, Claus Emmelmann & Josef Schlattmann
Additive Metal Deposition (AMD) is an additive manufacturing process building parts based on a nozzle-fed powder by laser assisted solidification. The AMD technology offers unique advantages for the production of near net-shape parts. In contrast to the powder bed-based technologies it provides a high productivity grade. Today AMD lacks reproducible process strategies manufacturing large parts in narrow tolerances. The building height of a single layer and the geometrical shape of a whole part alter progressively...

Theoretische und experimentelle Untersuchungen über die Verringerung des Wellenwiderstandes gegebener Schiffsformen durch den Bugwulst (Abschlußbericht)

Alfred Kracht
Theoretische und experimentelle Untersuchungen über die Verringerung des Wellenwiderstandes gegebener Schiffsformen durch den Bugwulst

Validated solution of large linear systems

Siegfried M. Rump
Some new methods will be presented for computing verified inclusions of the solution of large linear systems. The matrix of the linear system is typically of band or sparse structure. There are no prerequisites to the matrix such as being M-matrix, symmetric, positive definite or diagonally dominant. (...) Examples with up to 1.000.000 unknowns will be presented.

Assessing India's lead market potential for cost‐effective innovations

Rajnish Tiwari & Cornelius Herstatt
The purpose of the present study is to assess India’s potential as a lead market for cost-effective frugal innovations. This is of special interest since lead markets have traditionally existed in economically highly developed countries, whereas developing countries have faced negative country-of-origin effects. In the case of India a reversal of this trend may be observed, for some time. The paper aims to identify factors which are impacting India’s emerging role as a fountainhead of...

Die Berechnung der Bewegungsgrößen der gekoppelten Tauch- und Stampfschwingungen nach der erweiterten Streifentheorie von Grim und die Berechnung der Wahrscheinlichkeit für das Überschreiten bestimmter Schranken durch diese Größen

Maria Kirsch
Die Berechnung der Bewegungsgrößen der gekoppelten Tauch- und Stampfschwingungen nach der erweiterten Streifentheorie von Grim und die Berechnung der Wahrscheinlichkeit für das Überschreiten bestimmter Schranken durch diese Größen

Über den Einfluß nichtlinearer Effekte auf hydrodynamische Kräfte bei erzwungenen Tauchbewegungen prismatischer Körper

Cheung Hun Kim
Über den Einfluß nichtlinearer Effekte auf hydrodynamische Kräfte bei erzwungenen Tauchbewegungen prismatischer Körper

Finite volume schemes for multidimensional hyperbolic systems based on the use of bicharacteristics

Mária Medviďová-Lukáčová
In this survey paper we present an overview on recent results for the bicharacteristics based finite volume schemes, the so-called finite volume evolution Galerkin (FVEG) schemes. These methods were proposed to solve multidimensional hyperbolic conservation laws. They combine the usually conflicting design objectives of using the conservation form and following the characteritics, or bicharacteritics. This is realized by combining the finite volume formulation with approximate evolution operators, which use bicharacteristics of multidimensional hyperbolic system. In...

Comparative study of the path integration method and the stochastic averaging method for nonlinear roll motion in random beam seas

Wei Chai, Leo Dostal, Arvid Naess & Bernt J. Leira
In this work, the path integration method and the energy-based stochastic averaging method are introduced in order to study the stochastic responses of ship roll motion in random beam seas. Based on the Markov property of the dynamical system, the path integration (PI) method provides approximate solution to the governing Fokker-Planck (FP) equation. On the other hand, the stochastic averaging method leads to a dimension reduction of the original system, but the essential behavior is...

Ultrasonic joining of through-the-thickness reinforced metal-composite hybrid structures

Eduardo Etzberger Feistauer
Verbindungskonzepte, die traditionell für den Verbinden von Metall-Verbundstoff-Strukturen verwendet werden, weisen mehrere Beschränkungen in Bezug auf den Lasttransfer zwischen den Materialien. Die vorliegende Doktorarbeit zielt auf die Einführung von Ultrasonic Joining (U-Joining) ab, einem neuen Fügeverfahren zur Herstellung von throught-the-thickness verstärkten Hybridverbindungen aus Metall und Faserverbundwerkstoff mit verbesserter out-of-plane Festigkeit. Um die Machbarkeit des Fügeprozesses zu demonstrieren und die Korrelation zwischen Prozess- und Fügeeigenschaften zu beschreiben, wurde ein Fallstudienansatz gewählt, der kommerziell erhältliches glasfaserverstärktes Polyetherimid...

Autonomous vehicles and autonomous driving in freight transport

Heike Flämig
The degree of vehicle automation is continuously rising in all modes of transport both on public traffic infrastructure and in-house transport within company grounds, in order to improve the productivity, reliability, and flexibility of transport.

Nonlinear model parameter identification for ice-induced vibrations

Leo Dostal, Eliz-Mari Lourens & Andrei Metrikine
The problem of level ice interacting with compliant structures is addressed, where the ice loads can depend on the dynamical behavior of the structures. We are interested in a special type of ice-induced vibration, known as frequency lock-in, and characterized by having the dominant frequency of the ice forces near a natural frequency of the structure. It is shown that accurate estimates of the model parameters for the well-known Määttänen's model for ice-induced vibrations can...

Wie zuverlässig sind die Ergebnisse unserer Rechenanlagen?

Siegfried M. Rump
Mit dem Aufkommen preiswerter elektronischer Geräte in den letzten Jahren hat die Verbreitung von Rechenhilfsmitteln stark zugenommen. ...

Auswertung von Bahnkurven freifahrender Schiffsmodelle

Peter Oltmann
Auswertung von Bahnkurven freifahrender Schiffsmodelle

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