TY - CHAP A1 - Götten, Falk A1 - Havermann, Marc A1 - Braun, Carsten A1 - Gomez, Francisco A1 - Bil, Cees T1 - On the Applicability of Empirical Drag Estimation Methods for Unmanned Air Vehicle Design Read More: https://arc.aiaa.org/doi/10.2514/6.2018-3192 T2 - 2018 Aviation Technology, Integration, and Operations Conference, AIAA AVIATION Forum Y1 - 2018 U6 - https://doi.org/10.2514/6.2018-3192 SN - 1533-385X N1 - AIAA 2018-3192 SP - Article 3192 ER - TY - CHAP A1 - Weiss, Christian A1 - Heslenfeld, Jonas A1 - Saewe, Jasmin Kathrin A1 - Bremen, Sebastian A1 - Häfner, Constantin Leon T1 - Investigation on the influence of powder humidity in Laser Powder Bed Fusion (LPBF) T2 - Procedia CIRP 12th CIRP Conference on Photonic Technologies [LANE 2022] N2 - In the Laser Powder Bed Fusion (LPBF) process, parts are built out of metal powder material by exposure of a laser beam. During handling operations of the powder material, several influencing factors can affect the properties of the powder material and therefore directly influence the processability during manufacturing. Contamination by moisture due to handling operations is one of the most critical aspects of powder quality. In order to investigate the influences of powder humidity on LPBF processing, four materials (AlSi10Mg, Ti6Al4V, 316L and IN718) are chosen for this study. The powder material is artificially humidified, subsequently characterized, manufactured into cubic samples in a miniaturized process chamber and analyzed for their relative density. The results indicate that the processability and reproducibility of parts made of AlSi10Mg and Ti6Al4V are susceptible to humidity, while IN718 and 316L are barely influenced. KW - LPBF KW - Additive Manufacturing KW - Powder Material KW - Humidity Y1 - 2022 U6 - https://doi.org/10.1016/j.procir.2022.08.102 SN - 2212-8271 N1 - 12th CIRP Conference on Photonic Technologies [LANE 2022], 04. September 2022 bis 08. September 2022, Fürth VL - 111 SP - 115 EP - 120 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Butenweg, Christoph ED - Kuzmanović, Vladan ED - Ignjatović, Ivan T1 - Integrated approach for monitoring and management of buildings with digital building models and modern sensor technologies T2 - Proceedings of the International Conference Civil Engineering 2021 - Achievements and Visions N2 - Nowadays modern high-performance buildings and facilities are equipped with monitoring systems and sensors to control building characteristics like energy consumption, temperature pattern and structural safety. The visualization and interpretation of sensor data is typically based on simple spreadsheets and non-standardized user-oriented solutions, which makes it difficult for building owners, facility managers and decision-makers to evaluate and understand the data. The solution of this problem in the future are integrated BIM-Sensor approaches which allow the generation of BIM models incorporating all relevant information of monitoring systems. These approaches support both the dynamic visualization of key structural performance parameters, the effective long-term management of sensor data based on BIM and provide a user-friendly interface to communicate with various stakeholders. A major benefit for the end user is the use of the BIM software architecture, which is the future standard anyway. In the following, the application of the integrated BIM-Sensor approach is illustrated for a typical industrial facility as a part of an early warning and rapid response system for earthquake events currently developed in the research project “ROBUST” with financial support by the German Federal Ministry for Economic Affairs and Energy (BMWI). Y1 - 2021 N1 - Civil Engineering 2021 – Achievements and Visions, University of Belgrade, October 25 – 26, 2021 Belgrade, Serbia SP - 67 EP - 75 PB - University of Belgrade CY - Belgrade ER - TY - CHAP A1 - Lu, S. A1 - Beyer, K. A1 - Bosiljkov, V. A1 - Butenweg, Christoph A1 - D’Ayala, D. A1 - Degee, H. A1 - Gams, M. A1 - Klouda, J. A1 - Lagomarsino, S. A1 - Penna, A. A1 - Mojsilovic, N. A1 - da Porto, F. A1 - Sorrentino, L. A1 - Vintzileou, E. ED - Modena, Claudio ED - da Porto, F. ED - Valluzzi, M.R. T1 - Next generation of Eurocode 8, masonry chapter T2 - Brick and Block Masonry Proceedings of the 16th International Brick and Block Masonry Conference, Padova, Italy, 26-30 June 2016 N2 - This paper describes the procedure on the evaluation of the masonry chapter for the next generation of Eurocode 8, the European Standard for earthquake-resistant design. In CEN, TC 250/SC8, working group WG 1 has been established to support the subcommittee on the topic of masonry on both design of new structures (EN1998-1) and assessment of existing structures (EN1998-3). The aim is to elaborate suggestions for amendments which fit the current state of the art in masonry and earthquake-resistant design. Focus will be on modelling, simplified methods, linear-analysis (q-values, overstrength-values), nonlinear procedures, out-of-plane design as well as on clearer definition of limit states. Beside these, topics related to general material properties, reinforced masonry, confined masonry, mixed structures and non-structural infills will be covered too. This paper presents the preliminary work and results up to the submission date. Y1 - 2016 SN - 978-1-138-02999-6 (Print) SN - 9781315374963 (E-Book) SP - 695 EP - 700 PB - Taylor & Francis CY - London ER - TY - CHAP A1 - Pirovano, Laura A1 - Seefeldt, Patric A1 - Dachwald, Bernd A1 - Noomen, Ron T1 - Attitude and orbital modeling of an uncontrolled solar-sail experiment in low-Earth orbit T2 - 25th International Symposium on Space Flight Dynamics ISSFD N2 - Gossamer-1 is the first project of the three-step Gossamer roadmap, the purpose of which is to develop, prove and demonstrate that solar-sail technology is a safe and reliable propulsion technique for long-lasting and high-energy missions. This paper firstly presents the structural analysis performed on the sail to understand its elastic behavior. The results are then used in attitude and orbital simulations. The model considers the main forces and torques that a satellite experiences in low-Earth orbit coupled with the sail deformation. Doing the simulations for varying initial conditions in attitude and rotation rate, the results show initial states to avoid and maximum rotation rates reached for correct and faulty deployment of the sail. Lastly comparisons with the classic flat sail model are carried out to test the hypothesis that the elastic behavior does play a role in the attitude and orbital behavior of the sail KW - Solar sail KW - Gossamer structures KW - Attitude dynamics KW - Orbital dynamics Y1 - 2015 N1 - 25th International Symposium on Space Flight Dynamics ISSFD October 19 – 23, 2015, Munich, Germany https://issfd.org/2015/ SP - 1 EP - 15 ER - TY - CHAP A1 - Dachwald, Bernd A1 - Seboldt, Wolfgang A1 - Loeb, Horst W. A1 - Schartner, Karl-Heinz T1 - A comparison of SEP and NEP for a main belt asteroid sample return mission T2 - 7th International Symposium on Launcher Technologies, Barcelona, Spain, 02-05 April 2007 N2 - Innovative interplanetary deep space missions, like a main belt asteroid sample return mission, require ever larger velocity increments (∆V s) and thus ever more demanding propulsion capabilities. Providing much larger exhaust velocities than chemical high-thrust systems, electric low-thrust space-propulsion systems can significantly enhance or even enable such high-energy missions. In 1995, a European-Russian Joint Study Group (JSG) presented a study report on “Advanced Interplanetary Missions Using Nuclear-Electric Propulsion” (NEP). One of the investigated reference missions was a sample return (SR) from the main belt asteroid (19) Fortuna. The envisaged nuclear power plant, Topaz-25, however, could not be realized and also the worldwide developments in space reactor hardware stalled. In this paper, we investigate, whether such a mission is also feasible using a solar electric propulsion (SEP) system and compare our SEP results to corresponding NEP results. Y1 - 2007 SP - 1 EP - 10 ER - TY - CHAP A1 - Zähl, Philipp M. A1 - Theis, Sabine A1 - Wolf, Martin R. A1 - Köhler, Klemens ED - Chen, Jessie Y. C. ED - Fragomeni, Gino T1 - Teamwork in software development and what personality has to do with it - an overview T2 - Virtual, Augmented and Mixed Reality N2 - Due to the increasing complexity of software projects, software development is becoming more and more dependent on teams. The quality of this teamwork can vary depending on the team composition, as teams are always a combination of different skills and personality types. This paper aims to answer the question of how to describe a software development team and what influence the personality of the team members has on the team dynamics. For this purpose, a systematic literature review (n=48) and a literature search with the AI research assistant Elicit (n=20) were conducted. Result: A person’s personality significantly shapes his or her thinking and actions, which in turn influences his or her behavior in software development teams. It has been shown that team performance and satisfaction can be strongly influenced by personality. The quality of communication and the likelihood of conflict can also be attributed to personality. KW - Teamwork KW - Software KW - Personality KW - Performance KW - Elicit Y1 - 2023 SN - 978-3-031-35633-9 (Print) SN - 978-3-031-35634-6 (Online) U6 - https://doi.org/10.1007/978-3-031-35634-6_10 N1 - Virtual, Augmented and Mixed Reality: 15th International Conference. VAMR 2023. Held as Part of the 25th HCI International Conference. HCII 2023. Copenhagen, Denmark. July 23–28, 2023. SP - 130 EP - 153 PB - Springer CY - Cham ER - TY - CHAP A1 - Eggert, Mathias A1 - Dyong, Julian T1 - Applying process mining in small and medium sized IT enterprises – challenges and guidelines T2 - Business Process Management, 20th International Conference, BPM 2022, Proceedings N2 - Process mining gets more and more attention even outside large enterprises and can be a major benefit for small and medium sized enterprises (SMEs) to gain competitive advantages. Applying process mining is challenging, particularly for SMEs because they have less resources and process maturity. So far, IS researchers analyzed process mining challenges with a focus on larger companies. This paper investigates the application of process mining by means of a case study and sheds light into the particular challenges of an IT SME. The results reveal 13 SME process mining challenges and seven guidelines to address them. In this way, the paper contributes to the understanding of process mining application in SME and shows similarities and differences to larger companies. KW - Process mining KW - Challenges KW - Guidelines KW - SME KW - Case Study Y1 - 2022 SN - 978-3-031-16103-2 U6 - https://doi.org/10.1007/978-3-031-16103-2_11 N1 - International Conference on Business Process Management (BPM 2022), Münster, Germany, Sept. 11-16, 2022 SP - 125 EP - 142 PB - Springer CY - Cham ER - TY - CHAP A1 - Dachwald, Bernd A1 - Seboldt, Wolfgang A1 - Häusler, Bernd T1 - Performance requirements for near-term interplanetary solar sailcraft missions T2 - 6th International AAAF Symposium on Space Propulsion: Propulsion for Space Transportation of the XXIst Century N2 - Solar sailcraft provide a wide range of opportunities for high-energy low-cost missions. To date, most mission studies require a rather demanding performance that will not be realized by solar sailcraft of the first generation. However, even with solar sailcraft of moderate performance, scientifically relevant missions are feasible. This is demonstrated with a Near Earth Asteroid sample return mission and various planetary rendezvous missions. Y1 - 2002 N1 - 6th International AAAF Symposium on Space Propulsion: Propulsion for Space Transportation of the XXIst Century, Versailles, France, 14-16 May 2002 ER - TY - CHAP A1 - Bung, Daniel Bernhard A1 - Valero, Daniel ED - Dewals, Benjamin T1 - Image processing techniques for velocity estimation in highly aerated flows: bubble image velocimetry vs. optical flow T2 - Sustainable Hydraulics in the Era of Global Change : Proceedings of the 4th IAHR Europe Congress (Liege, Belgium, 27-29 July 2016) Y1 - 2016 SN - 978-1-138-02977-4 SN - 978-1-4987-8149-7 (eBook) U6 - https://doi.org/10.1201/b21902-31 SP - 151 EP - 157 PB - CRC Press ER - TY - CHAP A1 - Oertel, M. A1 - Bung, Daniel Bernhard ED - Crookston, B. ED - Tullis, B. T1 - Scouring processes downstream a crossbar block ramp BT - Session 3: Scour, erosion, sedimentation T2 - Hydraulic Structures and Water System Management. 6th IAHR International Symposium on Hydraulic Structures, Portland, OR, 27-30 June 2016 Y1 - 2016 SN - 978-1-884575-75-4 U6 - https://doi.org/10.15142/T3340628160853 SP - 549 EP - 559 ER - TY - CHAP A1 - Alexopoulos, Spiros A1 - Kluczka, Sven A1 - Vaeßen, Christiane A1 - Roeb, M. A1 - Neises, M. T1 - Scenario development for efficient methanol production using CO2 and solar energy T2 - Eurosun 2012 : Solar energy for a brighter future : conference proceedings : Rijeka, 18.-22.09.2012 Y1 - 2012 SP - ID 99 CY - Rijeka ER - TY - CHAP A1 - Dachwald, Bernd A1 - Kahle, Ralph A1 - Wie, Bong T1 - Head-on impact deflection of NEAs: a case study for 99942 Apophis T2 - Planetary Defense Conference 2007 N2 - Near-Earth asteroid (NEA) 99942 Apophis provides a typical example for the evolution of asteroid orbits that lead to Earth-impacts after a close Earth-encounter that results in a resonant return. Apophis will have a close Earth-encounter in 2029 with potential very close subsequent Earth-encounters (or even an impact) in 2036 or later, depending on whether it passes through one of several less than 1 km-sized gravitational keyholes during its 2029-encounter. A pre-2029 kinetic impact is a very favorable option to nudge the asteroid out of a keyhole. The highest impact velocity and thus deflection can be achieved from a trajectory that is retrograde to Apophis orbit. With a chemical or electric propulsion system, however, many gravity assists and thus a long time is required to achieve this. We show in this paper that the solar sail might be the better propulsion system for such a mission: a solar sail Kinetic Energy Impactor (KEI) spacecraft could impact Apophis from a retrograde trajectory with a very high relative velocity (75-80 km/s) during one of its perihelion passages. The spacecraft consists of a 160 m × 160 m, 168 kg solar sail assembly and a 150 kg impactor. Although conventional spacecraft can also achieve the required minimum deflection of 1 km for this approx. 320 m-sized object from a prograde trajectory, our solar sail KEI concept also allows the deflection of larger objects. For a launch in 2020, we also show that, even after Apophis has flown through one of the gravitational keyholes in 2029, the solar sail KEI concept is still feasible to prevent Apophis from impacting the Earth, but many KEIs would be required for consecutive impacts to increase the total Earth-miss distance to a safe value Y1 - 2007 N1 - Planetary Defense Conference 2007, Wahington D.C., USA, 05-08 March 2007 SP - 1 EP - 12 ER - TY - CHAP A1 - Ferrein, Alexander A1 - Maier, Christopher A1 - Mühlbacher, Clemens A1 - Niemüller, Tim A1 - Steinbauer, Gerald A1 - Vassos, Stravros T1 - Controlling logistics robots with the action-based language YAGI T2 - Intelligent Robotics and Applications: 9th International Conference, ICIRA 2016, Tokyo, Japan, August 22-24, 2016, Proceedings, Part I Y1 - 2016 SN - 978-3-319-43505-3 (Print) SN - 978-3-319-43506-0 (Online) U6 - https://doi.org/10.1007/978-3-319-43506-0_46 N1 - Series: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) VL - 9834 SP - 525 EP - 537 PB - Springer ER - TY - CHAP A1 - Braun, Carsten A1 - Boucke, Alexander A1 - Ballmann, Josef T1 - Numerical prediction of the wing deformation of a high speed transport aircraft type wind tunnel model by direct aeroelastic simulation T2 - Conference proceedings : CEAS/AIAA/DGLR International Forum on Aeroelasticity and Structural Dynamics IFASD 2005 : München, June 28 - July 1, 2005. DGLR-Bericht. 2005,04 Y1 - 2005 SN - 3-932182-43-X PB - DGLR CY - Bonn ER - TY - CHAP A1 - Eichenbaum, Julian A1 - Nikolovski, Gjorgji A1 - Mülhens, Leon A1 - Reke, Michael A1 - Ferrein, Alexander A1 - Scholl, Ingrid T1 - Towards a lifelong mapping approach using Lanelet 2 for autonomous open-pit mine operations T2 - 2023 IEEE 19th International Conference on Automation Science and Engineering (CASE) N2 - Autonomous agents require rich environment models for fulfilling their missions. High-definition maps are a well-established map format which allows for representing semantic information besides the usual geometric information of the environment. These are, for instance, road shapes, road markings, traffic signs or barriers. The geometric resolution of HD maps can be as precise as of centimetre level. In this paper, we report on our approach of using HD maps as a map representation for autonomous load-haul-dump vehicles in open-pit mining operations. As the mine undergoes constant change, we also need to constantly update the map. Therefore, we follow a lifelong mapping approach for updating the HD maps based on camera-based object detection and GPS data. We show our mapping algorithm based on the Lanelet 2 map format and show our integration with the navigation stack of the Robot Operating System. We present experimental results on our lifelong mapping approach from a real open-pit mine. Y1 - 2023 SN - 979-8-3503-2069-5 (Online) SN - 979-8-3503-2070-1 (Print) U6 - https://doi.org/10.1109/CASE56687.2023.10260526 N1 - 19th International Conference on Automation Science and Engineering (CASE), 26-30 August 2023, Auckland, New Zealand. PB - IEEE ER - TY - CHAP A1 - Niemueller, Tim A1 - Reuter, Sebastian A1 - Ewert, Daniel A1 - Ferrein, Alexander A1 - Jeschke, Sabina A1 - Lakemeyer, Gerhard ED - Almeida, Luis T1 - The Carologistics Approach to Cope with the Increased Complexity and New Challenges of the RoboCup Logistics League 2015 T2 - RoboCup 2015: Robot World Cup XIX Y1 - 2016 SN - 978-3-319-29339-4 U6 - https://doi.org/10.1007/978-3-319-29339-4_4 N1 - Lecture Notes in Computer Science ; 9513 SP - 47 EP - 59 PB - Springer International Publishing CY - Cham ER - TY - CHAP A1 - Konstantinidis, K. A1 - Kowalski, Julia A1 - Martinez, C. F. A1 - Dachwald, Bernd A1 - Ewerhart, D. A1 - Förstner, R. T1 - Some necessary technologies for in-situ astrobiology on enceladus T2 - Proceedings of the International Astronautical Congress Y1 - 2015 SN - 978-151081893-4 N1 - 6th International Astronautical Congress 2015: Space - The Gateway for Mankind's Future, IAC 2015; Jerusalem; Israel; 12 October 2015 through 16 October 2015 SP - 1354 EP - 1372 ER - TY - CHAP A1 - Dachwald, Bernd T1 - Low-Thrust Mission Analysis and Global Trajectory Optimization Using Evolutionary Neurocontrol: New Results T2 - European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007 N2 - 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 Y1 - 2007 ER - TY - CHAP A1 - Loeb, Horst W. A1 - Schartner, Karl-Heinz A1 - Seboldt, Wolfgang A1 - Dachwald, Bernd A1 - Streppel, Joern A1 - Meusemann, Hans A1 - Schülke, Peter T1 - SEP for a lander mission to the jovian moon europa T2 - 57th International Astronautical Congress N2 - Under DLR-contract, Giessen University and DLR Cologne are studying solar-electric propulsion missions (SEP) to the outer regions of the solar system. The most challenging reference mission concerns the transport of a 1.35-tons chemical lander spacecraft into an 80-RJ circular orbit around Jupiter, which would enable to place a 375 kg lander with 50 kg of scientific instruments on the surface of the icy moon "Europa". Thorough analyses show that the best solution in terms of SEP launch mass times thrusting time would be a two-stage EP module and a triple-junction solar array with concentrators which would be deployed step by step. Mission performance optimizations suggest to propel the spacecraft in the first EP stage by 6 gridded ion thrusters, running at 4.0 kV of beam voltage, which would save launch mass, and in the second stage by 4 thrusters with 1.25 to 1.5 kV of positive high voltage saving thrusting time. In this way, the launch mass of the spacecraft would be kept within 5.3 tons. Without a launcher's C3 and interplanetary gravity assists, Jupiter might be reached within about 4 yrs. The spiraling-down into the parking orbit would need another 1.8 yrs. This "large mission" can be scaled down to a smaller one, e.g., by halving all masses, the solar array power, and the number of thrusters. Due to their reliability, long lifetime and easy control, RIT-22 engines have been chosen for mission analysis. Based on precise tests, the thruster performance has been modeled. Y1 - 2006 U6 - https://doi.org/10.2514/6.IAC-06-C4.4.04 N1 - 57th International Astronautical Congress, 02 October 2006 - 06 October 2006, Valencia, Spain. SP - 1 EP - 12 ER -