@inproceedings{FunkeBoernerRobinsonetal.2010, author = {Funke, Harald and B{\"o}rner, Sebastian and Robinson, A. and Hendrick, P. and Recker, E.}, title = {Low NOx H2 combustion for industrial gas turbines of various power ranges}, year = {2010}, 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} } @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} } @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} } @inproceedings{FerreinSteinbauer2010, author = {Ferrein, Alexander and Steinbauer, Gerald}, title = {On the Way to High-Level Programming for Resource-Limited Embedded Systems with Golog}, 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_23}, pages = {229 -- 240}, year = {2010}, abstract = {In order to allow an autonomous robot to perform non-trivial tasks like to explore a foreign planet the robot has to have deliberative capabilities like reasoning or planning. Logic-based approaches like the programming and planing language Golog and it successors has been successfully used for such decision-making problems. A drawback of this particular programing language is that their interpreter usually are written in Prolog and run on a Prolog back-end. Such back-ends are usually not available or feasible on resource-limited robot systems. In this paper we present our ideas and first results of a re-implementation of the interpreter based on the Lua scripting language which is available on a wide range of systems including small embedded systems.}, language = {en} } @inproceedings{RensVarzinczakMeyeretal.2010, author = {Rens, Gavin and Varzinczak, Ivan and Meyer, Thomas and Ferrein, Alexander}, title = {A Logic for Reasoning about Actions and Explicit Observations}, series = {AI 2010: Advances in Artificial Intelligence}, booktitle = {AI 2010: Advances in Artificial Intelligence}, publisher = {Springer}, address = {Berlin}, doi = {10.1007/978-3-642-17432-2_40}, pages = {395 -- 404}, year = {2010}, abstract = {We propose a formalism for reasoning about actions based on multi-modal logic which allows for expressing observations as first-class objects. We introduce a new modal operator, namely [o |α], which allows us to capture the notion of perceiving an observation given that an action has taken place. Formulae of the type [o |α]ϕ mean 'after perceiving observation o, given α was performed, necessarily ϕ'. In this paper, we focus on the challenges concerning sensing with explicit observations, and acting with nondeterministic effects. We present the syntax and semantics, and a correct and decidable tableau calculus for the logic}, 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} } @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} } @inproceedings{GerhardsBelloumBerretzetal.2010, author = {Gerhards, Michael and Belloum, Adam and Berretz, Frank and Sander, Volker and Skorupa, Sascha}, title = {A history-tracing XML-based provenance framework for workflows}, series = {The 5th Workshop on Workflows in Support of Large-Scale Science}, booktitle = {The 5th Workshop on Workflows in Support of Large-Scale Science}, publisher = {IEEE}, address = {New York}, isbn = {978-1-4244-8989-3}, doi = {10.1109/WORKS.2010.5671873}, pages = {10 Seiten}, year = {2010}, abstract = {The importance of validating and reproducing the outcome of computational processes is fundamental to many application domains. Assuring the provenance of workflows will likely become even more important with respect to the incorporation of human tasks to standard workflows by emerging standards such as WS-HumanTask. This paper addresses this trend by an actor-based workflow approach that actively support provenance. It proposes a framework to track and store provenance information automatically that applies for various workflow management systems. In particular, the introduced provenance framework supports the documentation of workflows in a legally binding way. The authors therefore use the concept of layered XML documents, i.e. history-tracing XML. Furthermore, the proposed provenance framework enables the executors (actors) of a particular workflow task to attest their operations and the associated results by integrating digital XML signatures.}, language = {en} }