@inproceedings{Dachwald2007, author = {Dachwald, Bernd}, title = {Low-Thrust Mission Analysis and Global Trajectory Optimization Using Evolutionary Neurocontrol: New Results}, series = {European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007}, booktitle = {European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007}, year = {2007}, abstract = {Interplanetary trajectories for low-thrust spacecraft are often characterized by multiple revolutions around the sun. Unfortunately, the convergence of traditional trajectory optimizers that are based on numerical optimal control methods depends strongly on an adequate initial guess for the control function (if a direct method is used) or for the starting values of the adjoint vector (if an indirect method is used). Especially when many revolutions around the sun are re- quired, trajectory optimization becomes a very difficult and time-consuming task that involves a lot of experience and expert knowledge in astrodynamics and optimal control theory, because an adequate initial guess is extremely hard to find. Evolutionary neurocontrol (ENC) was proposed as a smart method for low-thrust trajectory optimization that fuses artificial neural networks and evolutionary algorithms to so-called evolutionary neurocontrollers (ENCs) [1]. Inspired by natural archetypes, ENC attacks the trajectoryoptimization problem from the perspective of artificial intelligence and machine learning, a perspective that is quite different from that of optimal control theory. Within the context of ENC, a trajectory is regarded as the result of a spacecraft steering strategy that maps permanently the actual spacecraft state and the actual target state onto the actual spacecraft control vector. This way, the problem of searching the optimal spacecraft trajectory is equivalent to the problem of searching (or "learning") the optimal spacecraft steering strategy. An artificial neural network is used to implement such a spacecraft steering strategy. It can be regarded as a parameterized function (the network function) that is defined by the internal network parameters. Therefore, each distinct set of network parameters defines a different network function and thus a different steering strategy. The problem of searching the optimal steering strategy is now equivalent to the problem of searching the optimal set of network parameters. Evolutionary algorithms that work on a population of (artificial) chromosomes are used to find the optimal network parameters, because the parameters can be easily mapped onto a chromosome. The trajectory optimization problem is solved when the optimal chromosome is found. A comparison of solar sail trajectories that have been published by others [2, 3, 4, 5] with ENC-trajectories has shown that ENCs can be successfully applied for near-globally optimal spacecraft control [1, 6] and that they are able to find trajectories that are closer to the (unknown) global optimum, because they explore the trajectory search space more exhaustively than a human expert can do. The obtained trajectories are fairly accurate with respect to the terminal constraint. If a more accurate trajectory is required, the ENC-solution can be used as an initial guess for a local trajectory optimization method. Using ENC, low-thrust trajectories can be optimized without an initial guess and without expert attendance. Here, new results for nuclear electric spacecraft and for solar sail spacecraft are presented and it will be shown that ENCs find very good trajectories even for very difficult problems. Trajectory optimization results are presented for 1. NASA's Solar Polar Imager Mission, a mission to attain a highly inclined close solar orbit with a solar sail [7] 2. a mission to de ect asteroid Apophis with a solar sail from a retrograde orbit with a very-high velocity impact [8, 9] 3. JPL's \2nd Global Trajectory Optimization Competition", a grand tour to visit four asteroids from different classes with a NEP spacecraft}, language = {en} } @inproceedings{WolfUlbrich2007, author = {Wolf, Martin R. and Ulbrich, Daniel}, title = {Decision-Support-System kokas zur Sanierungsplanung und Strategieentwicklung}, year = {2007}, abstract = {Dr.-Ing. Martin Wolf ; Dipl.-Kaufm. Daniel Ulbrich , Dr. Pecher und Partner Ingenieurgesellschaft mbH, M{\"u}nchen. 31 S. (S. 139-168). Beitrag zum 1. Aachener Softwaretag in der Wasserwirtschaft < 1, 2007, Aachen>. Zusammenfasung [der Autoren] Die {\"o}ffentlichen Kanalnetze Deutschlands stellen mit einem Wert von rd. 330 Mrd. € ein enormes Anlageverm{\"o}gen dar. Auf Grund des oft schlechten Zustandes und geringer Ausgaben zur Instandhaltung und Erneuerung ist zu erwarten, dass durch die gegenw{\"a}rtige Sanierungspraxis eher ein Substanzwertverzehr des Kanalnetzes als ein Substanzwerterhalt im Sinne des Generationenvertrages erzielt wird. F{\"u}r einen nachhaltigen Betrieb und Erhalt der Kanalnetze sind deshalb Sanierungsstrategien erforderlich, die neben den technischen und gesetzlichen Anforderungen auch den mittel- und langfristigen Substanzwertverlauf ber{\"u}cksichtigen. Dieser wird beeinflusst vom erforderlichen oder durchgef{\"u}hrten Sanierungsumfang, Art und Zusammensetzung der ausgew{\"a}hlten Maßnahmen sowie der zeitlichen Abfolge der Sanierungsmaßnahmen. Erheblichen Einfluss auf den Substanzwertverlauf hat zudem die Ber{\"u}cksichtigung der hydraulischen Verh{\"a}ltnisse sowie der optisch nicht sichtbaren Undichtheiten. Entsprechend ist es erforderlich, die tats{\"a}chlich vorhandenen Defizite zu ermitteln und die Sanierungsmaßnahmen sowie eine Strategie zur Umsetzung zu erarbeiten. Da sich gezeigt hat, dass alleine die Einhaltung der technischen und gesetzlichen Anforderung f{\"u}r einen Substanzwerterhalt nicht ausreicht, muss die geplante Strategie im Dr.-Ing. Martin Wolf 139 von 170 Decision-Support-System kokas zur Sanierungsplanung und Strategieentwicklung 1. Aachener Softwaretag in der Wasserwirtschaft Hinblick auf die nachhaltige Wertentwicklung {\"u}berpr{\"u}ft und ggf. Anpassungen vorgenommen werden. Kurzfristig erzielte Einsparungen durch reduzierten Schadensumfang oder einseitige Maßnahmenwahl erm{\"o}glichen zwar im g{\"u}nstigsten Fall, die Anforderungen einzuhalten, gehen jedoch zwangsl{\"a}ufig zu Lasten des Substanzwertes und f{\"u}hren mittel- und langfristig zu einer Versch{\"a}rfung der Kosten- und Geb{\"u}hrensituation. Der monet{\"a}re, am konkreten Sanierungsaufwand orientierte Substanzwertansatz erm{\"o}glicht dabei, technische und kaufm{\"a}nnische Gesichtspunkte praxisnah zu verkn{\"u}pfen und den bestm{\"o}glichen Ausgleich zwischen den gegenl{\"a}ufigen Zielen Substanzwerterhalt und Geb{\"u}hrenkonstanz zu finden.}, subject = {Kanalisation}, language = {de} } @inproceedings{WeissAbanteribaEsch2007, author = {Weiss, Alexander and Abanteriba, Sylvester and Esch, Thomas}, title = {Investigation of Flow Separation Inside a Conical Rocket Nozzle With the Aid of an Annular Cross Flow}, series = {Proceedings of the ASME/JSME 2007 5th Joint Fluids Engineering Conference. Volume 1: Symposia, Parts A and B}, booktitle = {Proceedings of the ASME/JSME 2007 5th Joint Fluids Engineering Conference. Volume 1: Symposia, Parts A and B}, publisher = {American Society of Mechanical Engineers (ASME)}, address = {New York}, isbn = {0-7918-4288-6}, doi = {10.1115/FEDSM2007-37387}, pages = {1861 -- 1871}, year = {2007}, abstract = {Flow separation is a phenomenon that occurs in all kinds of supersonic nozzles sometimes during run-up and shut-down operations. Especially in expansion nozzles of rocket engines with large area ratio, flow separation can trigger strong side loads that can damage the structure of the nozzle. The investigation presented in this paper seeks to establish measures that may be applied to alter the point of flow separation. In order to achieve this, a supersonic nozzle was placed at the exit plane of the conical nozzle. This resulted in the generation of cross flow surrounding the core jet flow from the conical nozzle. Due to the entrainment of the gas stream from the conical nozzle the pressure in its exit plane was found to be lower than that of the ambient. A Cold gas instead of hot combustion gases was used as the working fluid. A mathematical simulation of the concept was validated by experiment. Measurements confirmed the simulation results that due to the introduction of a second nozzle the pressure in the separated region of the conical nozzle was significantly reduced. It was also established that the boundary layer separation inside the conical nozzle was delayed thus allowing an increased degree of overexpansion. The condition established by the pressure measurements was also demonstrated qualitatively using transparent nozzle configurations.}, language = {en} } @inproceedings{KoellenspergerBragardPlumetal.2007, author = {K{\"o}llensperger, P. and Bragard, Michael and Plum, T. and De Doncker, R. W.}, title = {The dual GCT : a new high-power device using optimized GCT technology}, series = {Conference record of the 2007 IEEE Industry Applications Conference : 42. IAS annual meeting ; September 23 - 27, 2007, New Orleans, Louisiana, USA}, booktitle = {Conference record of the 2007 IEEE Industry Applications Conference : 42. IAS annual meeting ; September 23 - 27, 2007, New Orleans, Louisiana, USA}, publisher = {IEEE Operations Center}, address = {Piscataway, NJ}, isbn = {978-1-4244-1260-0 (Online)}, doi = {10.1109/07IAS.2007.76}, pages = {358 -- 365}, year = {2007}, language = {en} } @inproceedings{Jacobs2007, author = {Jacobs, Stephan}, title = {Towards integration driven design : experience report}, series = {Software Engineering 2007 : Beitr{\"a}ge zu den Workshops ; Fachtagung des GI-Fachbereichs Softwaretechnik ; 27. - 30.03.2007 in Hamburg. - (GI-Edition : Proceedings ; 106)}, booktitle = {Software Engineering 2007 : Beitr{\"a}ge zu den Workshops ; Fachtagung des GI-Fachbereichs Softwaretechnik ; 27. - 30.03.2007 in Hamburg. - (GI-Edition : Proceedings ; 106)}, editor = {Bleek, Wolf-Gideon}, publisher = {Ges. f{\"u}r Informatik}, address = {Bonn}, isbn = {978-3-88579-200-0}, pages = {143 -- 150}, year = {2007}, language = {en} } @inproceedings{HagebeukerRingbeckFrydlewiczetal.2007, author = {Hagebeuker, Bianca and Ringbeck, Thorsten and Frydlewicz, Paul and Jesorsky, Oliver and S{\"u}nkel, Thomas}, title = {PMD-Sensoren als Schl{\"u}sselkomponenten f{\"u}r die mehrdimensionale Umfelderfassung des Fahrzeuginnenraums}, series = {Begleittexte zum Entwicklerforum KFZ-Elektronik \& FlexRay Solution Day : 15.Mai 2007, Ludwigsburg}, booktitle = {Begleittexte zum Entwicklerforum KFZ-Elektronik \& FlexRay Solution Day : 15.Mai 2007, Ludwigsburg}, editor = {Grote, Caspar}, publisher = {WEKA-Fachzeitschr.-Verl.}, address = {Poing}, pages = {287 -- 296}, year = {2007}, language = {en} } @inproceedings{TippkoetterStueckmannWinkelmannetal.2007, author = {Tippk{\"o}tter, Nils and St{\"u}ckmann, H. and Winkelmann, G. and Noack, U. and Beutel, S. and Scheper, T. and Ulber, Roland}, title = {Optimisation of antibody-labelling of gold colloids for their application in an immunchromatographic assay for microcystin-LR}, series = {European BioPerspectives : celebrating the 25th DECHEMA annual convention of biotechnologists ; 30 May - 1 June 2007, Cologne, Germany ; book of abstracts ; abstracts, poster programme}, booktitle = {European BioPerspectives : celebrating the 25th DECHEMA annual convention of biotechnologists ; 30 May - 1 June 2007, Cologne, Germany ; book of abstracts ; abstracts, poster programme}, publisher = {Dechema}, address = {Frankfurt am Main}, pages = {126}, year = {2007}, language = {en} } @inproceedings{Ritz2007, author = {Ritz, Thomas}, title = {Die benutzerzentrierte Entwicklung mobiler Unternehmenssoftware}, series = {MMS 2007: Mobilit{\"a}t und mobile Informationssysteme : 2nd conference of GI-Fachgruppe MMS ; March 6th, 2007 in Aachen, Germany}, booktitle = {MMS 2007: Mobilit{\"a}t und mobile Informationssysteme : 2nd conference of GI-Fachgruppe MMS ; March 6th, 2007 in Aachen, Germany}, editor = {K{\"o}nig-Ries, Brigitta}, publisher = {Ges. f{\"u}r Informatik}, address = {Bonn}, isbn = {978-3-88579-198-0}, pages = {23 -- 35}, year = {2007}, language = {de} } @inproceedings{WellmerChenBraunetal.2007, author = {Wellmer, Georg and Chen, B.-H. and Braun, Carsten and Ballmann, Josef}, title = {Numerical prediction of aeroelastic effects on twin-sting-rig mounted models for rear fuselage and empennage flow investigation in transonic windtunnel}, series = {Proceedings / IFASD 2007, CEAS/AIAA/KTH International Forum on Aeroelasticity and Structural Dynamics, June 18 - 21, 2007, Stockholm, Sweden}, booktitle = {Proceedings / IFASD 2007, CEAS/AIAA/KTH International Forum on Aeroelasticity and Structural Dynamics, June 18 - 21, 2007, Stockholm, Sweden}, publisher = {KTH}, address = {Stockholm}, organization = {Confederation of European Aerospace Societies ; American Institute of Aeronautics and Astronautics, Reston, Va. ; Kungliga Tekniska H{\"o}gskolan, Stockholm}, pages = {1 CD-ROM}, year = {2007}, language = {en} } @inproceedings{BragardKoellenspergerDeDoncker2007, author = {Bragard, Michael and K{\"o}llensperger, P. and De Doncker, R. W.}, title = {Der Internally Commutated Thyristor (ICT) : ein neuartiger GCT mit integrierter Ausschalteinheit}, series = {"Nowoczesne urządzenia zasilające w energetyce" : X międzynarodowa konferencja naukowo techniczna, Zakopane, 14-16 marca 2007 r. : materiały konferencyjne}, booktitle = {"Nowoczesne urządzenia zasilające w energetyce" : X międzynarodowa konferencja naukowo techniczna, Zakopane, 14-16 marca 2007 r. : materiały konferencyjne}, editor = {Dmowski, Antoni}, publisher = {APS Energia}, address = {Warszawa}, isbn = {83-918709-7-9}, pages = {7.1 -- 7.9}, year = {2007}, language = {de} }