@inproceedings{NiemuellerFerreinBecketal.2010, author = {Niem{\"u}ller, Tim and Ferrein, Alexander and Beck, Daniel and Lakemeyer, Gerhard}, title = {Design principles of the component-based robot software framework Fawkes}, series = {Simulation, Modeling, and Programming for Autonomous Robots}, booktitle = {Simulation, Modeling, and Programming for Autonomous Robots}, publisher = {Springer}, address = {Berlin}, doi = {10.1007/978-3-642-17319-6_29}, pages = {300 -- 311}, year = {2010}, abstract = {The idea of component-based software engineering was proposed more that 40 years ago, yet only few robotics software frameworks follow these ideas. The main problem with robotics software usually is that it runs on a particular platform and transferring source code to another platform is crucial. In this paper, we present our software framework Fawkes which follows the component-based software design paradigm by featuring a clear component concept with well-defined communication interfaces. We deployed Fawkes on several different robot platforms ranging from service robots to biped soccer robots. Following the component concept with clearly defined communication interfaces shows great benefit when porting robot software from one robot to the other. Fawkes comes with a number of useful plugins for tasks like timing, logging, data visualization, software configuration, and even high-level decision making. These make it particularly easy to create and to debug productive code, shortening the typical development cycle for robot software.}, language = {en} } @inproceedings{NiemuellerFerreinLakemeyer2010, author = {Niem{\"u}ller, Tim and Ferrein, Alexander and Lakemeyer, Gerhard}, title = {A Lua-based behavior engine for controlling the humanoid robot Nao}, series = {RoboCup 2009: Robot Soccer World Cup XIII}, booktitle = {RoboCup 2009: Robot Soccer World Cup XIII}, publisher = {Springer}, address = {Berlin}, doi = {10.1007/978-3-642-11876-0_21}, pages = {240 -- 251}, year = {2010}, abstract = {The high-level decision making process of an autonomous robot can be seen as an hierarchically organised entity, where strategical decisions are made on the topmost layer, while the bottom layer serves as driver for the hardware. In between is a layer with monitoring and reporting functionality. In this paper we propose a behaviour engine for this middle layer which, based on formalism of hybrid state machines (HSMs), bridges the gap between high-level strategic decision making and low-level actuator control. The behaviour engine has to execute and monitor behaviours and reports status information back to the higher level. To be able to call the behaviours or skills hierarchically, we extend the model of HSMs with dependencies and sub-skills. These Skill-HSMs are implemented in the lightweight but expressive Lua scripting language which is well-suited to implement the behaviour engine on our target platform, the humanoid robot Nao.}, language = {en} } @article{FerreinSiebelSteinbauer2010, author = {Ferrein, Alexander and Siebel, Nils T. and Steinbauer, Gerald}, title = {Hybrid control for autonomous systems — Integrating learning, deliberation and reactive control}, series = {Robotics and Autonomous Systems}, volume = {58}, journal = {Robotics and Autonomous Systems}, number = {9}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0921-8890}, doi = {10.1016/j.robot.2010.06.003}, pages = {1037 -- 1038}, year = {2010}, language = {en} } @article{LeimenaArtmannDachwaldetal.2010, author = {Leimena, W. and Artmann, Gerhard and Dachwald, Bernd and Temiz Artmann, Ayseg{\"u}l and Gossmann, Matthias and Digel, Ilya}, title = {Feasibility of an in-situ microbial decontamination of an ice-melting probe}, series = {Eurasian Chemico-Technological Journal}, volume = {12}, journal = {Eurasian Chemico-Technological Journal}, number = {2}, publisher = {Institute of Combustion Problems}, address = {Almaty}, isbn = {1562-3920}, doi = {10.18321/ectj37}, pages = {145 -- 150}, year = {2010}, abstract = {Autonomous robotic systems for penetrating thick ice shells with simultaneous collecting of scientific data are very promising devices in both terrestrial (glacier, climate research) and extra-terrestrial applications. Technical challenges in development of such systems are numerous and include 3D-navigation, an appropriate energy source, motion control, etc. Not less important is the problem of forward contamination of the pristine glacial environments with microorganisms and biomolecules from the surface of the probe. This study was devoted to establishing a laboratory model for microbial contamination of a newly constructed ice-melting probe called IceMole and to analyse the viability and amount of the contaminating microorganisms as a function of distance. The used bacterial strains were Bacillus subtilis (ATCC 6051) and Escherichia coli (ATCC 11775). The main objective was development of an efficient and reliable in-situ decontamination method of the melting probe. Therefore, several chemical substances were tested in respect of their efficacy to eliminate bacteria on the surface of the melting probe at low temperature (0 - 5 °C) and at continuous dilution by melted water. Our study has shown that at least 99.9\% decontamination of the IceMole can be successfully achieved by the injection of 30\% (v/v) hydrogen peroxide and 3\% (v/v) sodium hypochlorite into the drilling site. We were able to reproduce this result in both time-dependent and depth-dependent experiments. The sufficient amount of 30\% (v/v) H₂O₂ or 3\% (v/v) NaClO has been found to be approximately 18 L per cm² of the probe's surface.}, language = {en} } @misc{BehbahaniMaiWalugaetal.2010, author = {Behbahani, Mehdi and Mai, A. and Waluga, C. and Bergmann, B. and Tran, L. and Vonderstein, K. and Behr, Marek and Mottaghy, K.}, title = {Numerical Modeling of Flow-Related Thrombus Formation under Physiological and Non-Physiological Flow Conditions}, series = {Acta Physiologica}, volume = {198}, journal = {Acta Physiologica}, number = {Supplement 677}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {1748-1716}, pages = {185}, year = {2010}, abstract = {Aims: Thrombotic complications due to activation of platelets and plasmatic clotting factors belong still to the most investigated topics in the field of study of patho-physiological mechanisms. Mathematical modeling of thrombotic reactions is established and validated in test cases. Aim of this study is to experimentally evaluate and computationally simulate platelets under the influence of well-defined shear flow conditions. Platelet behaviour and reactions are experimentally reproduced, measured and used for validation of the numerical simulation. Methods: A mathematical model of platelet activation, adhesion and aggregation has been implemented into a finite element CFD (Computational Fluid Dynamics) code. The approach is based on the advective and diffusive transport equations for resting platelets, activated platelets and platelet released agonists. Adhesion rates for the reactive surfaces depend on the hemocompatibility properties of the surface and the local shear rate. Experiments with citrate-anticoagulated freshly-drawn whole blood are performed in a perfusion flow chamber as well as in a system of rotating cylinders for Couette and Taylor-vortex flow. Different biomaterials are used. The activation, drop of platelet concentration, adhesion and aggregation are quantified using scanning electron microscopy (SEM) and flow cytometry. Results: Regions and flow conditions with a high potential for thrombus growth could be identified. The experiments clearly show the influence of the blood contacting material and flow properties. By means of SEM diverse platelet adhesion patterns are observed. Numerical analysis can explain the patterns and the degree of thrombus formation. Conclusion: The numerical method shows good agreement with experimental data indicating a possible prediction of initiation of activation and detection of the local adhesion areas in connection with the role of Von-Willebrand-Factor.}, language = {en} } @article{BehbahaniMaiBergmannetal.2010, author = {Behbahani, Mehdi and Mai, A. and Bergmann, B. and Waluga, C. and Behr, Marek and Tran, L. and Vonderstein, K. and Mottaghy, K.}, title = {Modeling and Numerical Simulation of Blood Damage}, year = {2010}, language = {en} } @article{BehbahaniProbstMaietal.2010, author = {Behbahani, Mehdi and Probst, M. and Mai, A. and Behr, Marek and Tran, L. and Vonderstein, K. and Mottaghy, K.}, title = {Numerical Prediction of Blood Damage in Biomedical Devices}, year = {2010}, language = {en} } @article{ProbstBehbahaniBorrmannetal.2010, author = {Probst, M. and Behbahani, Mehdi and Borrmann, E. and Elgeti, S. and Nicolai, M. and Behr, Marek}, title = {Hemodynamic Modeling for Numerical Analysis and Design of Medical Devices}, year = {2010}, language = {en} } @misc{BehbahaniNamWalugaetal.2010, author = {Behbahani, Mehdi and Nam, J. and Waluga, C. and Behr, Marek and Pasquali, M. and Mottaghy, K.}, title = {Modeling and Numerical Analysis of Platelet Activation, Adhesion and Aggregation in Artificial Organs}, series = {ASAIO Journal}, volume = {56}, journal = {ASAIO Journal}, number = {2}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1538-943X}, doi = {10.1097/01.mat.0000369377.65122.a3}, pages = {85}, year = {2010}, abstract = {Purpose of Study: Thrombosis-related complications are among the leading causes for morbidity and mortality in patients who depend on artificial organs. For the prediction of platelet behavior both the flow conditions inside the device and the thrombogenic properties of the blood-contacting surfaces must be considered. Platelet reactions under the influence of well-defined shear rates are experimentally evaluated and numerically simulated. The approach is intended for the analysis of VAD and oxygenator design. Methods Used: A mathematical model of platelet activation, adhesion and aggregation has been implemented into a finite element CFD (Computational Fluid Dynamics) code. The approach is based on the advective and diffusive transport equations for resting and activated platelets and platelet released agonists. Experiments with citrate-anticoagulated freshly-drawn whole blood are performed in a perfusion flow chamber as well as in a system of rotating cylinders for Couette and Taylor-vortex flow. Different biomaterials are used. The activation, adhesion and aggregation are quantified using scanning electron microscopy and flow cytometry. Summary of Results: Regions and flow conditions with a high potential for thrombus growth could be identified. The experiments clearly show the influence of the blood contacting material and governing shear rates. Numerical analysis can explain observed adhesion patterns and the degree of thrombus formation}, language = {en} } @article{JansenBehbahaniLaumenetal.2010, author = {Jansen, S. V. and Behbahani, Mehdi and Laumen, M. and Kaufmann, T. and Hormes, M. and Behr, Marek and Schmitz-Rode, T. and Steinseifer, U.}, title = {Investigation of Steady Flow Through a Realistic Model of the Thoracic Human Aorta Using 3D Stereo PIV and CFD-Simulation}, series = {ASAIO Journal}, volume = {56}, journal = {ASAIO Journal}, number = {2}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, doi = {10.1097/01.mat.0000369377.65122.a3}, pages = {98}, year = {2010}, language = {en} } @misc{NamAroraBehbahanietal.2010, author = {Nam, J. and Arora, D. and Behbahani, Mehdi and Probst, M. and Benkowski, R. and Behr, Marek and Pasquali, M.}, title = {New computational method in hemolysis analysis for artificial heart pump}, series = {ASAIO Journal}, volume = {56}, journal = {ASAIO Journal}, number = {2}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, doi = {10.1097/01.mat.0000369377.65122.a3}, pages = {98}, year = {2010}, abstract = {The MicroMed DeBakey ventricular assist device is an axial flow pump designed for providing long-term support to end-stage heartfailure patients. Previously, we presented computational analysis of the blood pump flow. From the analysis, we were able to identify regions of high shear and recirculating flow that may cause blood damage, for example, deformation and fragmentation of the red blood cell (RBC). This mechanical hemolysis can be predicted using a tensor-based blood damage model that is based on the physical properties of the RBCs, for example, the relaxation time of the RBC membrane. However, an extensive and detailed analysis was complicated by the fact that the previous method predicts hemolysis along a finite number of pathlines traversed by the RBCs, possibly omitting parts of the flow domain. Furthermore, it is computationally expensive and is not easily parallelizable. Here, we propose a new method to estimate hemolysis. The method is based on treating the shape of droplet (tensor) as a field variable, like velocity in the Navier-Stokes system. The governing equation for the RBC shape is treated by least-squares finite element method and the volume conservation of the RBC is augmented by Lagrangian multiplier. Unlike the previous method, the proposed method can visualize areas of high RBC strain that is potentially dangerous for mechanical hemolysis. Also, the amount of plasma-free hemoglobin and, consequently, normalized index of hemolysis can be computed as a byproduct. The method is tested in a simple shear flow for validation and an artery graft flow is chosen to show its potential usefulness. Finally, the method is applied to the blood damage estimation for the pump.}, language = {en} } @article{GoettscheHoffschmidtSchmitzetal.2010, author = {G{\"o}ttsche, Joachim and Hoffschmidt, Bernhard and Schmitz, Stefan and Sauerborn, Markus}, title = {Solar Concentrating Systems Using Small Mirror Arrays}, series = {Journal of solar energy engineering}, volume = {132}, journal = {Journal of solar energy engineering}, number = {1}, publisher = {ASME}, address = {New York}, issn = {0199-6231}, doi = {10.1115/1.4000332}, pages = {4 Seiten}, year = {2010}, abstract = {The cost of solar tower power plants is dominated by the heliostat field making up roughly 50\% of investment costs. Classical heliostat design is dominated by mirrors brought into position by steel structures and drives that guarantee high accuracies under wind loads and thermal stress situations. A large fraction of costs is caused by the stiffness requirements of the steel structure, typically resulting in ~ 20 kg/m² steel per mirror area. The typical cost figure of heliostats (figure mentioned by Solucar at Solar Paces Conference, Seville, 2006) is currently in the area of 150 €/m² caused by the increasing price of the necessary raw materials. An interesting option to reduce costs lies in a heliostat design where all moving parts are protected from wind loads. In this way, drives and mechanical layout may be kept less robust, thereby reducing material input and costs. In order to keep the heliostat at an appropriate size, small mirrors (around 10x10 cm²) have to be used, which are placed in a box with a transparent cover. Innovative drive systems are developed in order to obtain a cost-effective design. A 0,5x0,5 m² demonstration unit will be constructed. Tests of the unit are carried out with a high-precision artificial sun unit that imitates the sun's path with an accuracy of less than 0.5 mrad and creates a beam of parallel light with a divergence of less than 4 mrad.}, language = {en} } @article{Hillgaertner2010, author = {Hillg{\"a}rtner, Michael}, title = {Normative Regulations}, series = {ECPE Cluster Seminar EMC in Hybrid and Electric Vehicles : 18 May 2010, Fraunhofer Institute Erlangen}, journal = {ECPE Cluster Seminar EMC in Hybrid and Electric Vehicles : 18 May 2010, Fraunhofer Institute Erlangen}, publisher = {European Center for Power Electronics}, address = {N{\"u}rnberg}, year = {2010}, language = {en} } @inproceedings{BoernerFunkeHendricketal.2010, author = {B{\"o}rner, Sebastian and Funke, Harald and Hendrick, P. and Recker, E.}, title = {Control system modifications for a hydrogen fuelled gas-turbine}, series = {Proceedings of ISROMAC 13}, booktitle = {Proceedings of ISROMAC 13}, publisher = {Curran}, address = {Red Hook, NY}, isbn = {978-1-617-38848-4}, pages = {665 -- 670}, year = {2010}, language = {en} } @misc{JansenBehbahaniLaumenetal.2010, author = {Jansen, Sebastian and Behbahani, Mehdi and Laumen, Marco and Kaufmann, Tim and Hormes, Marcus and Schmitz-Rode, Thomas and Behr, Marek and Steinseifer, Ulrich}, title = {3D stereo-PIV validation for CFD-simulation of steady flow through the human aorta using rapid-prototyping techniques}, year = {2010}, language = {en} } @article{BehbahaniProbstMaietal.2010, author = {Behbahani, Mehdi and Probst, M. and Mai, A. and Tran, L. and Vonderstein, K. and Keschenau, P. and Linde, T. and Steinseifer, U. and Behr, Marek and Mottaghy, K.}, title = {The influence of high shear on thrombosis and hemolysis in artificial organs}, series = {The International Journal of Artificial Organs}, volume = {33}, journal = {The International Journal of Artificial Organs}, number = {7}, publisher = {Sage}, address = {Thousand Oaks}, issn = {0391-3988}, pages = {426 -- 426}, year = {2010}, language = {en} } @misc{MaiwaldDachwald2010, author = {Maiwald, Volker and Dachwald, Bernd}, title = {Mission design for a multiple-rendezvous mission to Jupiter's trojans}, pages = {3}, year = {2010}, abstract = {In this paper, we will provide a feasible mission design for a multiple-rendezvous mission to Jupiter's Trojans. It is based on solar electric propulsion, as being currently used on the DAWN spacecraft, and other flight-proven technology. First, we have selected a set of mission objectives, the prime objective being the detection of water -especially subsurface water -to provide evidence for the Trojans' formation at large solar distances. Based on DAWN and other comparable missions, we have determined suitable payload instruments to achieve these objectives. Afterwards, we have designed a spacecraft that is able to carry the selected payload to the Trojan region and rendezvous successively with three target bodies within a maximum mission duration of 15 years. Accurate low-thrust trajectories have been obtained with a global low-thrust trajectory optimization program (InTrance). During the transfer from Earth to the first target, the spacecraft is propelled by two RIT-22 ion engines from EADS Astrium, whereas a single RIT-15 is used for transfers within the Trojan region to reduce the required power. For power generation, the spacecraft uses a multi-junction solar array that is supported by concentrators. To achieve moderate mission costs, we have restricted the launch mass to a maximum of 1600 kg, the maximum interplanetary injection capability of a Soyuz/Fregat launcher. Our final layout has a mass of 1400 kg, yielding a margin of about 14\%. Nestor (a member of the L4-population) was determined as the first mission target. It can be reached within 4.6 years from launch. The fuel mass ratio for this transfer is about 35\%. The stay time at Nestor is 1.2 years. Eurymedon was selected as the second target (transfer time 3.5 years, stay time 3.0 years) and Irus as the third target (transfer time 2.2 years). The transfers within the Trojan L4-population can be accomplished with fuel mass ratios of about 3\% for each trajectory leg. Including the stay times in orbit around the targets, the mission can be accomplished within a total duration of about 14.5 years. According to our mission analysis, it is also feasible to fly to the L5-population with similar flight times. It has to be noted that -for a first analysis -we have taken only the named targets into account. Allowing also rendezvous with unnamed objects will very likely decrease the mission duration. Based on a scaling of DAWN's mission costs (due to comparable scientific instruments and mission objectives), and taking into account the longer mission duration and the potential re-use of already developed technology, we have estimated that these three rendezvous can be accomplished with a budget of about 250 Million Euros, i.e. about 25\% of ROSETTA's budget.}, language = {en} } @misc{AlexopoulosHoffschmidt2010, author = {Alexopoulos, Spiros and Hoffschmidt, Bernhard}, title = {Solarthermische Kraftwerke mit thermischen Speichern}, series = {Chemie Ingenieur Technik}, volume = {82}, journal = {Chemie Ingenieur Technik}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, isbn = {1522-2640}, doi = {10.1002/cite.201050678}, pages = {1606}, year = {2010}, abstract = {Solarthermische Kraftwerke stellen eine bedeutende Technologieoption f{\"u}r einen nachhaltigen Energiemix der Zukunft dar. Sie konzentrieren die Strahlung der Sonne, erzeugen W{\"a}rme und wandeln diese mit konventioneller Kraftwerkstechnik in Strom um. Die W{\"a}rme kann auch gespeichert werden, so dass der Betrieb w{\"a}hrend des Durchzugs von Wolken m{\"o}glich ist und bis in die Abendstunden hinein verl{\"a}ngert werden kann. Zu den solarthermischen Kraftwerken geh{\"o}ren neben der Parabolrinne und dem Solarturm der Fresnel-Kollektor und die Dish-Stirling-Systeme. Im Zuge einer sp{\"a}teren Vergr{\"o}ßerung des Solarfeldes von Solarkraftwerken kann mithilfe von thermischen Energiespeichern die solare Energieerzeugung bei gleichbleibender Kraftwerksleistung sukzessiv bis um den Faktor 3 erweitert werden. Es besteht so die M{\"o}glichkeit einer massiven Substitution von fossilen Brennstoffen.Bei den ersten solarthermischen Speichern f{\"u}r die SEGS-Parabolrinnekraftwerke wurde {\"O}l als Speichermedium eingesetzt. Ein weiteres Speichermedium ist Salzschmelze, die im Andasol-1-Projekt in Spanien sowie bei Solarturmkraftwerken eingesetzt wird. Beton ist ein weiteres m{\"o}gliches Speichermaterial f{\"u}r Parabolrinnensysteme. Eine weitere Alternative bei einem Solarturmkraftwerk mit Luft als W{\"a}rmetr{\"a}germedium ist die Verwendung von keramischen Feuerfestmaterialien in Form von Sch{\"u}ttungen oder stapelbaren, por{\"o}sen Elementen. In J{\"u}lich wurde das weltweit erste solarthermische Turmkraftwerk mit einer Leistung von 1,5 MWe, das Luft als W{\"a}rmetr{\"a}germedium einsetzt und einen solchen Speicher verwendet, gebaut.}, language = {de} } @inproceedings{GeimerSauerbornHoffschmidtetal.2010, author = {Geimer, Konstantin and Sauerborn, Markus and Hoffschmidt, Bernhard and Schmitz, Mark and G{\"o}ttsche, Joachim}, title = {Test facility for absorber specimens of solar tower power plants}, series = {Advances in Science and Technology}, volume = {74}, booktitle = {Advances in Science and Technology}, publisher = {Trans Tech Publications}, address = {Baech}, doi = {10.4028/www.scientific.net/AST.74.266}, pages = {266 -- 271}, year = {2010}, abstract = {The Solar-Institute J{\"u}lich (SIJ) has initiated the construction of the first and only German solar tower power plant and is now involved in the accompanying research. The power plant for experimental and demonstration purposes in the town of J{\"u}lich started supplying electric energy in the beginning of 2008. The central receiver plant features as central innovation an open volumetric receiver, consisting of porous ceramic elements that simultaneously absorb the concentrated sunlight and transfer the heat to ambient air passing through the pores so that an average temperature of 680°C is reached. The subsequent steam cycle generates up to 1.5 MWe. A main field of research at the SIJ is the optimization of the absorber structures. To analyze the capability of new absorber specimens a special test facility was developed and set up in the laboratory. A high-performance near-infrared radiator offers for single test samples a variable and repeatable beam with a power of up to 320 kW/m² peak. The temperatures achieved on the absorber surface can reach more than 1000°C. To suck ambient air through the open absorber - like on the tower - it is mounted on a special blower system. An overview about the test facility and some recent results will be presented.}, language = {en} } @article{GebhardtSchmidtHoetteretal.2010, author = {Gebhardt, Andreas and Schmidt, Frank-Michael and H{\"o}tter, Jan-Steffen and Sokalla, Wolfgang and Sokalla, Patrick}, title = {Additive manufacturing by selective laser melting the realizer desktop machine and its application for the dental industry}, series = {Physics Procedia}, volume = {5 B}, journal = {Physics Procedia}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1875-3892}, doi = {10.1016/j.phpro.2010.08.082}, pages = {543 -- 549}, year = {2010}, abstract = {Additive Manufacturing of metal parts by Selective Laser Melting has become a powerful tool for the direct manufacturing of complex parts mainly for the aerospace and medical industry. With the introduction of its desktop machine, Realizer targeted the dental market. The contribution describes the special features of the machine, discusses details of the process and shows manufacturing results focused on metal dental devices.}, language = {en} }