@incollection{HoffschmidtAlexopoulosRauetal.2022,
  author    = {Hoffschmidt, Bernhard and Alexopoulos, Spiros and Rau, Christoph and Sattler, Johannes, Christoph and Anthrakidis, Anette and Teixeira Boura, Cristiano Jos{\´e} and O'Connor, B. and Chico Caminos, R.A. and Rend{\´o}n, C. and Hilger, P.},
  title     = {Concentrating solar power},
  series = {Comprehensive Renewable Energy (Second Edition) / Volume 3: Solar Thermal Systems: Components and Applications},
  booktitle = {Comprehensive Renewable Energy (Second Edition) / Volume 3: Solar Thermal Systems: Components and Applications},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {978-0-12-819734-9},
  pages     = {670 -- 724},
  year      = {2022},
  abstract  = {The focus of this chapter is the production of power and the use of the heat produced from concentrated solar thermal power (CSP) systems. The chapter starts with the general theoretical principles of concentrating systems including the description of the concentration ratio, the energy and mass balance. The power conversion systems is the main part where solar-only operation and the increase in operational hours. Solar-only operation include the use of steam turbines, gas turbines, organic Rankine cycles and solar dishes. The operational hours can be increased with hybridization and with storage. Another important topic is the cogeneration where solar cooling, desalination and of heat usage is described. Many examples of commercial CSP power plants as well as research facilities from the past as well as current installed and in operation are described in detail. The chapter closes with economic and environmental aspects and with the future potential of the development of CSP around the world.},
  language  = {en}
}
@inproceedings{EggertKriska2022,
  author    = {Eggert, Mathias and Kriska, Melina},
  title     = {Gamification for software development processes - relevant affordances and design principles},
  series = {Proceedings of the 55th Hawaii International Conference on System Sciences},
  booktitle = {Proceedings of the 55th Hawaii International Conference on System Sciences},
  publisher = {HICSS Publishing},
  address   = {Honolulu},
  isbn      = {978-0-9981331-5-7},
  doi       = {10.24251/HICSS.2022.200},
  pages     = {1614 -- 1623},
  year      = {2022},
  abstract  = {A Gamified Information System (GIS) implements game concepts and elements, such as affordances and game design principles to motivate people. Based on the idea to develop a GIS to increase the motivation of software developers to perform software quality tasks, the research work at hand aims at investigating relevant requirements from that target group. Therefore, 14 interviews with software development experts are conducted and analyzed. According to the results, software developers prefer the affordances points, narrative storytelling in a multiplayer and a round-based setting. Furthermore, six design principles for the development of a GIS are derived.},
  language  = {en}
}
@article{DefosseKleinschmidtSchmutzetal.2022,
  author    = {Defosse, Jerome and Kleinschmidt, Joris and Schmutz, Axel and Loop, Torsten and Staat, Manfred and Gatzweiler, Karl-Heinz and Wappler, Frank and Schieren, Mark},
  title     = {Dental strain on maxillary incisors during tracheal intubation with double-lumen tubes and different laryngoscopy techniques - a blinded manikin study},
  series = {Journal of Cardiothoracic and Vascular Anesthesia},
  volume    = {36},
  journal   = {Journal of Cardiothoracic and Vascular Anesthesia},
  number    = {8, Part B},
  publisher = {Elsevier},
  address   = {New York, NY},
  issn      = {1053-0770},
  doi       = {10.1053/j.jvca.2022.02.017},
  pages     = {3021 -- 3027},
  year      = {2022},
  language  = {en}
}
@article{MandekarHollandThielenetal.2022,
  author    = {Mandekar, Swati and Holland, Abigail and Thielen, Moritz and Behbahani, Mehdi and Melnykowycz, Mark},
  title     = {Advancing towards Ubiquitous EEG, Correlation of In-Ear EEG with Forehead EEG},
  series = {Sensors},
  volume    = {22},
  journal   = {Sensors},
  number    = {4},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1424-8220},
  doi       = {10.3390/s22041568},
  pages     = {1 -- 19},
  year      = {2022},
  abstract  = {Wearable EEG has gained popularity in recent years driven by promising uses outside of clinics and research. The ubiquitous application of continuous EEG requires unobtrusive form-factors that are easily acceptable by the end-users. In this progression, wearable EEG systems have been moving from full scalp to forehead and recently to the ear. The aim of this study is to demonstrate that emerging ear-EEG provides similar impedance and signal properties as established forehead EEG. EEG data using eyes-open and closed alpha paradigm were acquired from ten healthy subjects using generic earpieces fitted with three custom-made electrodes and a forehead electrode (at Fpx) after impedance analysis. Inter-subject variability in in-ear electrode impedance ranged from 20 kΩ to 25 kΩ at 10 Hz. Signal quality was comparable with an SNR of 6 for in-ear and 8 for forehead electrodes. Alpha attenuation was significant during the eyes-open condition in all in-ear electrodes, and it followed the structure of power spectral density plots of forehead electrodes, with the Pearson correlation coefficient of 0.92 between in-ear locations ELE (Left Ear Superior) and ERE (Right Ear Superior) and forehead locations, Fp1 and Fp2, respectively. The results indicate that in-ear EEG is an unobtrusive alternative in terms of impedance, signal properties and information content to established forehead EEG.},
  language  = {en}
}
@article{HagenkampBlankeDoering2021,
  author    = {Hagenkamp, Markus and Blanke, Tobias and D{\"o}ring, Bernd},
  title     = {Thermoelectric building temperature control: a potential assessment},
  series = {International Journal of Energy and Environmental Engineering},
  volume    = {13},
  journal   = {International Journal of Energy and Environmental Engineering},
  publisher = {Springer},
  address   = {Berlin},
  doi       = {10.1007/s40095-021-00424-x},
  pages     = {241 -- 254},
  year      = {2021},
  abstract  = {This study focuses on thermoelectric elements (TEE) as an alternative for room temperature control. TEE are semi-conductor devices that can provide heating and cooling via a heat pump effect without direct noise emissions and no refrigerant use. An efficiency evaluation of the optimal operating mode is carried out for different numbers of TEE, ambient temperatures, and heating loads. The influence of an additional heat recovery unit on system efficiency and an unevenly distributed heating demand are examined. The results show that TEE can provide heat at a coefficient of performance (COP) greater than one especially for small heating demands and high ambient temperatures. The efficiency increases with the number of elements in the system and is subject to economies of scale. The best COP exceeds six at optimal operating conditions. An additional heat recovery unit proves beneficial for low ambient temperatures and systems with few TEE. It makes COPs above one possible at ambient temperatures below 0 ∘C. The effect increases efficiency by maximal 0.81 (from 1.90 to 2.71) at ambient temperature 5 K below room temperature and heating demand Q˙h=100W but is subject to diseconomies of scale. Thermoelectric technology is a valuable option for electricity-based heat supply and can provide cooling and ventilation functions. A careful system design as well as an additional heat recovery unit significantly benefits the performance. This makes TEE superior to direct current heating systems and competitive to heat pumps for small scale applications with focus on avoiding noise and harmful refrigerants.},
  language  = {en}
}
@article{TopcuMadabhushiStaat2022,
  author    = {Top{\c{c}}u, Murat and Madabhushi, Gopal S.P. and Staat, Manfred},
  title     = {A generalized shear-lag theory for elastic stress transfer between matrix and fibres having a variable radius},
  series = {International Journal of Solids and Structures},
  volume    = {239-240},
  journal   = {International Journal of Solids and Structures},
  number    = {Art. No. 111464},
  publisher = {Elsevier},
  address   = {New York, NY},
  issn      = {0020-7683},
  doi       = {10.1016/j.ijsolstr.2022.111464},
  year      = {2022},
  abstract  = {A generalized shear-lag theory for fibres with variable radius is developed to analyse elastic fibre/matrix stress transfer. The theory accounts for the reinforcement of biological composites, such as soft tissue and bone tissue, as well as for the reinforcement of technical composite materials, such as fibre-reinforced polymers (FRP). The original shear-lag theory proposed by Cox in 1952 is generalized for fibres with variable radius and with symmetric and asymmetric ends. Analytical solutions are derived for the distribution of axial and interfacial shear stress in cylindrical and elliptical fibres, as well as conical and paraboloidal fibres with asymmetric ends. Additionally, the distribution of axial and interfacial shear stress for conical and paraboloidal fibres with symmetric ends are numerically predicted. The results are compared with solutions from axisymmetric finite element models. A parameter study is performed, to investigate the suitability of alternative fibre geometries for use in FRP.},
  language  = {en}
}
@article{EngemannCoenenDawaretal.2021,
  author    = {Engemann, Heiko and C{\"o}nen, Patrick and Dawar, Harshal and Du, Shengzhi and Kallweit, Stephan},
  title     = {A robot-assisted large-scale inspection of wind turbine blades in manufacturing using an autonomous mobile manipulator},
  series = {Applied Sciences},
  volume    = {11},
  journal   = {Applied Sciences},
  number    = {19},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2076-3417},
  doi       = {10.3390/app11199271},
  pages     = {1 -- 22},
  year      = {2021},
  abstract  = {Wind energy represents the dominant share of renewable energies. The rotor blades of a wind turbine are typically made from composite material, which withstands high forces during rotation. The huge dimensions of the rotor blades complicate the inspection processes in manufacturing. The automation of inspection processes has a great potential to increase the overall productivity and to create a consistent reliable database for each individual rotor blade. The focus of this paper is set on the process of rotor blade inspection automation by utilizing an autonomous mobile manipulator. The main innovations include a novel path planning strategy for zone-based navigation, which enables an intuitive right-hand or left-hand driving behavior in a shared human-robot workspace. In addition, we introduce a new method for surface orthogonal motion planning in connection with large-scale structures. An overall execution strategy controls the navigation and manipulation processes of the long-running inspection task. The implemented concepts are evaluated in simulation and applied in a real-use case including the tip of a rotor blade form.},
  language  = {en}
}
@inproceedings{NikolovskiRekeElsenetal.2021,
  author    = {Nikolovski, Gjorgji and Reke, Michael and Elsen, Ingo and Schiffer, Stefan},
  title     = {Machine learning based 3D object detection for navigation in unstructured environments},
  series = {2021 IEEE Intelligent Vehicles Symposium Workshops (IV Workshops)},
  booktitle = {2021 IEEE Intelligent Vehicles Symposium Workshops (IV Workshops)},
  publisher = {IEEE},
  isbn      = {978-1-6654-7921-9},
  doi       = {10.1109/IVWorkshops54471.2021.9669218},
  pages     = {236 -- 242},
  year      = {2021},
  abstract  = {In this paper we investigate the use of deep neural networks for 3D object detection in uncommon, unstructured environments such as in an open-pit mine. While neural nets are frequently used for object detection in regular autonomous driving applications, more unusual driving scenarios aside street traffic pose additional challenges. For one, the collection of appropriate data sets to train the networks is an issue. For another, testing the performance of trained networks often requires tailored integration with the particular domain as well. While there exist different solutions for these problems in regular autonomous driving, there are only very few approaches that work for special domains just as well. We address both the challenges above in this work. First, we discuss two possible ways of acquiring data for training and evaluation. That is, we evaluate a semi-automated annotation of recorded LIDAR data and we examine synthetic data generation. Using these datasets we train and test different deep neural network for the task of object detection. Second, we propose a possible integration of a ROS2 detector module for an autonomous driving platform. Finally, we present the performance of three state-of-the-art deep neural networks in the domain of 3D object detection on a synthetic dataset and a smaller one containing a characteristic object from an open-pit mine.},
  language  = {en}
}
@inproceedings{HauggKreyerKemperetal.2020,
  author    = {Haugg, Albert Thomas and Kreyer, J{\"o}rg and Kemper, Hans and Hatesuer, Katerina and Esch, Thomas},
  title     = {Heat exchanger for ORC. adaptability and optimisation potentials},
  series = {IIR International Rankine 2020 Conference},
  booktitle = {IIR International Rankine 2020 Conference},
  doi       = {10.18462/iir.rankine.2020.1224},
  pages     = {10 Seiten},
  year      = {2020},
  abstract  = {The recovery of waste heat requires heat exchangers to extract it from a liquid or gaseous medium into another working medium, a refrigerant. In Organic Rankine Cycles (ORC) on Combustion Engines there are two major heat sources, the exhaust gas and the water/glycol fluid from the engine's cooling circuit. A heat exchanger design must be adapted to the different requirements and conditions resulting from the heat sources, fluids, system configurations, geometric restrictions, and etcetera. The Stacked Shell Cooler (SSC) is a new and very specific design of a plate heat exchanger, created by AKG, which allows with a maximum degree of freedom the optimization of heat exchange rate and the reduction of the related pressure drop. This optimization in heat exchanger design for ORC systems is even more important, because it reduces the energy consumption of the system and therefore maximizes the increase in overall efficiency of the engine.},
  language  = {en}
}
@inproceedings{SchaenzleAltherrEdereretal.2015,
  author    = {Sch{\"a}nzle, Christian and Altherr, Lena and Ederer, Thorsten and Pelz, Peter},
  title     = {TOR - Towards the energetically optimal ventilation system},
  pages     = {1 Seite},
  year      = {2015},
  language  = {en}
}
@inproceedings{LorenzAltherrPelz2020,
  author    = {Lorenz, Imke-Sophie and Altherr, Lena and Pelz, Peter F.},
  title     = {Resilience enhancement of critical infrastructure - graph-theoretical resilience analysis of the water distribution system in the German city of Darmstadt},
  series = {14th WCEAM Proceedings},
  booktitle = {14th WCEAM Proceedings},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-030-64228-0},
  doi       = {10.1007/978-3-030-64228-0_13},
  pages     = {137 -- 149},
  year      = {2020},
  abstract  = {Water suppliers are faced with the great challenge of achieving high-quality and, at the same time, low-cost water supply. Since climatic and demographic influences will pose further challenges in the future, the resilience enhancement of water distribution systems (WDS), i.e. the enhancement of their capability to withstand and recover from disturbances, has been in particular focus recently. To assess the resilience of WDS, graph-theoretical metrics have been proposed. In this study, a promising approach is first physically derived analytically and then applied to assess the resilience of the WDS for a district in a major German City. The topology based resilience index computed for every consumer node takes into consideration the resistance of the best supply path as well as alternative supply paths. This resistance of a supply path is derived to be the dimensionless pressure loss in the pipes making up the path. The conducted analysis of a present WDS provides insight into the process of actively influencing the resilience of WDS locally and globally by adding pipes. The study shows that especially pipes added close to the reservoirs and main branching points in the WDS result in a high resilience enhancement of the overall WDS.},
  language  = {en}
}
@incollection{LeiseAltherr2021,
  author    = {Leise, Philipp and Altherr, Lena},
  title     = {Experimental evaluation of resilience metrics in a fluid system},
  series = {Mastering Uncertainty in Mechanical Engineering},
  booktitle = {Mastering Uncertainty in Mechanical Engineering},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-030-78356-3},
  pages     = {442 -- 447},
  year      = {2021},
  language  = {en}
}
@incollection{AltherrLeisePfetschetal.2021,
  author    = {Altherr, Lena and Leise, Philipp and Pfetsch, Marc E. and Schmitt, Andreas},
  title     = {Optimal design of resilient technical systems on the example of water supply systems},
  series = {Mastering Uncertainty in Mechanical Engineering},
  booktitle = {Mastering Uncertainty in Mechanical Engineering},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-030-78356-3},
  pages     = {429 -- 433},
  year      = {2021},
  language  = {en}
}
@incollection{AltherrLeise2021,
  author    = {Altherr, Lena and Leise, Philipp},
  title     = {Resilience as a concept for mastering uncertainty},
  series = {Mastering Uncertainty in Mechanical Engineering},
  booktitle = {Mastering Uncertainty in Mechanical Engineering},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-030-78353-2},
  doi       = {10.1007/978-3-030-78354-9},
  pages     = {412 -- 417},
  year      = {2021},
  language  = {en}
}
@incollection{Golland2020,
  author    = {Golland, Alexander},
  title     = {Struggling with users' consent: Economic approach to solve the issue of coupling},
  series = {Turning Point in Data Protection Law},
  booktitle = {Turning Point in Data Protection Law},
  publisher = {Nomos},
  address   = {Baden-Baden},
  isbn      = {978-3-8487-6909-4},
  doi       = {10.5771/9783748921561-121},
  pages     = {121 -- 126},
  year      = {2020},
  language  = {en}
}
@incollection{GollandOhrtmann2020,
  author    = {Golland, Alexander and Ohrtmann, Jan-Peter},
  title     = {Video surveillance: The supervisory authorities' view andrecent case law},
  series = {Turning Point in Data Protection Law},
  booktitle = {Turning Point in Data Protection Law},
  publisher = {Nomos},
  address   = {Baden-Baden},
  isbn      = {978-3-8487-6909-4},
  doi       = {10.5771/9783748921561-175},
  pages     = {175 -- 178},
  year      = {2020},
  language  = {en}
}
@article{PoettgenEdererAltherretal.2015,
  author    = {P{\"o}ttgen, Philipp and Ederer, Thorsten and Altherr, Lena and Pelz, Peter F.},
  title     = {Developing a control strategy for booster stations under uncertain load},
  series = {Applied Mechanics and Materials},
  volume    = {807},
  journal   = {Applied Mechanics and Materials},
  number    = {807},
  publisher = {Trans Tech Publications},
  address   = {B{\"a}ch},
  isbn      = {1662-7482},
  doi       = {10.4028/www.scientific.net/AMM.807.241},
  pages     = {241 -- 246},
  year      = {2015},
  abstract  = {Booster stations can fulfill a varying pressure demand with high energy-efficiency, because individual pumps can be deactivated at smaller loads. Although this is a seemingly simple approach, it is not easy to decide precisely when to activate or deactivate pumps. Contemporary activation controls derive the switching points from the current volume flow through the system. However, it is not measured directly for various reasons. Instead, the controller estimates the flow based on other system properties. This causes further uncertainty for the switching decision. In this paper, we present a method to find a robust, yet energy-efficient activation strategy.},
  language  = {en}
}
@article{AltherrEdererPoettgenetal.2015,
  author    = {Altherr, Lena and Ederer, Thorsten and P{\"o}ttgen, Philipp and Lorenz, Ulf and Pelz, Peter F.},
  title     = {Multicriterial optimization of technical systems considering multiple load and availability scenarios},
  series = {Applied Mechanics and Materials},
  volume    = {807},
  journal   = {Applied Mechanics and Materials},
  editor    = {Pelz, Peter F. and Groche, Peter},
  isbn      = {1660-9336},
  doi       = {10.4028/www.scientific.net/AMM.807.247},
  pages     = {247 -- 256},
  year      = {2015},
  abstract  = {Cheap does not imply cost-effective -- this is rule number one of zeitgeisty system design. The initial investment accounts only for a small portion of the lifecycle costs of a technical system. In fluid systems, about ninety percent of the total costs are caused by other factors like power consumption and maintenance. With modern optimization methods, it is already possible to plan an optimal technical system considering multiple objectives. In this paper, we focus on an often neglected contribution to the lifecycle costs: downtime costs due to spontaneous failures. Consequently, availability becomes an issue.},
  language  = {en}
}
@inproceedings{AltherrEdererFarnetaneetal.2017,
  author    = {Altherr, Lena and Ederer, Thorsten and Farnetane, Lucas S. and P{\"o}ttgen, Philipp and Verg{\´e}, Angela and Pelz, Peter F.},
  title     = {Multicriterial design of a hydrostatic transmission system via mixed-integer programming},
  series = {Operations Research Proceedings 2015},
  booktitle = {Operations Research Proceedings 2015},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-42901-4},
  doi       = {10.1007/978-3-319-42902-1_41},
  pages     = {301 -- 307},
  year      = {2017},
  abstract  = {In times of planned obsolescence the demand for sustainability keeps growing. Ideally, a technical system is highly reliable, without failures and down times due to fast wear of single components. At the same time, maintenance should preferably be limited to pre-defined time intervals. Dispersion of load between multiple components can increase a system's reliability and thus its availability inbetween maintenance points. However, this also results in higher investment costs and additional efforts due to higher complexity. Given a specific load profile and resulting wear of components, it is often unclear which system structure is the optimal one. Technical Operations Research (TOR) finds an optimal structure balancing availability and effort. We present our approach by designing a hydrostatic transmission system.},
  language  = {en}
}
@article{PoettgenEdererAltherretal.2015,
  author    = {P{\"o}ttgen, Philipp and Ederer, Thorsten and Altherr, Lena and Lorenz, Ulf and Pelz, Peter F.},
  title     = {Examination and optimization of a heating circuit for energy-efficient buildings},
  series = {Energy Technology},
  volume    = {4},
  journal   = {Energy Technology},
  number    = {1},
  publisher = {WILEY-VCH Verlag},
  address   = {Weinheim},
  isbn      = {2194-4296},
  doi       = {10.1002/ente.201500252},
  pages     = {136 -- 144},
  year      = {2015},
  abstract  = {The conference center darmstadtium in Darmstadt is a prominent example of energy efficient buildings. Its heating system consists of different source and consumer circuits connected by a Zortstr{\"o}m reservoir. Our goal was to reduce the energy costs of the system as much as possible. Therefore, we analyzed its supply circuits. The first step towards optimization is a complete examination of the system: 1) Compilation of an object list for the system, 2) collection of the characteristic curves of the components, and 3) measurement of the load profiles of the heat and volume-flow demand. Instead of modifying the system manually and testing the solution by simulation, the second step was the creation of a global optimization program. The objective was to minimize the total energy costs for one year. We compare two different topologies and show opportunities for significant savings.},
  language  = {en}
}
@incollection{AltherrDoerigEdereretal.2017,
  author    = {Altherr, Lena and D{\"o}rig, Bastian and Ederer, Thorsten and Pelz, Peter Franz and Pfetsch, Marc and Wolf, Jan},
  title     = {A mixed-integer nonlinear program for the design of gearboxes},
  series = {Operations Research Proceedings 2016},
  booktitle = {Operations Research Proceedings 2016},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-55701-4},
  doi       = {10.1007/978-3-319-55702-1_31},
  pages     = {227 -- 233},
  year      = {2017},
  abstract  = {Gearboxes are mechanical transmission systems that provide speed and torque conversions from a rotating power source. Being a central element of the drive train, they are relevant for the efficiency and durability of motor vehicles. In this work, we present a new approach for gearbox design: Modeling the design problem as a mixed-integer nonlinear program (MINLP) allows us to create gearbox designs from scratch for arbitrary requirements and—given enough time—to compute provably globally optimal designs for a given objective. We show how different degrees of freedom influence the runtime and present an exemplary solution.},
  language  = {en}
}
@article{AltherrBroetzDietrichetal.2018,
  author    = {Altherr, Lena and Br{\"o}tz, Nicolas and Dietrich, Ingo and Gally, Tristan and Geßner, Felix and Kloberdanz, Hermann and Leise, Philipp and Pelz, Peter Franz and Schlemmer, Pia and Schmitt, Andreas},
  title     = {Resilience in mechanical engineering - a concept for controlling uncertainty during design, production and usage phase of load-carrying structures},
  series = {Applied Mechanics and Materials},
  volume    = {885},
  journal   = {Applied Mechanics and Materials},
  publisher = {Trans Tech Publications},
  address   = {B{\"a}ch},
  isbn      = {1662-7482},
  doi       = {10.4028/www.scientific.net/AMM.885.187},
  pages     = {187 -- 198},
  year      = {2018},
  abstract  = {Resilience as a concept has found its way into different disciplines to describe the ability of an individual or system to withstand and adapt to changes in its environment. In this paper, we provide an overview of the concept in different communities and extend it to the area of mechanical engineering. Furthermore, we present metrics to measure resilience in technical systems and illustrate them by applying them to load-carrying structures. By giving application examples from the Collaborative Research Centre (CRC) 805, we show how the concept of resilience can be used to control uncertainty during different stages of product life.},
  language  = {en}
}
@inproceedings{SchaenzleAltherrEdereretal.2015,
  author    = {Sch{\"a}nzle, Christian and Altherr, Lena and Ederer, Thorsten and Lorenz, Ulf and Pelz, Peter F.},
  title     = {As good as it can be: Ventilation system design by a combined scaling and discrete optimization method},
  series = {Proceedings of FAN 2015},
  booktitle = {Proceedings of FAN 2015},
  pages     = {1 -- 11},
  year      = {2015},
  abstract  = {The understanding that optimized components do not automatically lead to energy-efficient systems sets the attention from the single component on the entire technical system. At TU Darmstadt, a new field of research named Technical Operations Research (TOR) has its origin. It combines mathematical and technical know-how for the optimal design of technical systems. We illustrate our optimization approach in a case study for the design of a ventilation system with the ambition to minimize the energy consumption for a temporal distribution of diverse load demands. By combining scaling laws with our optimization methods we find the optimal combination of fans and show the advantage of the use of multiple fans.},
  language  = {en}
}
@inproceedings{AltherrEdererSchaenzleetal.2017,
  author    = {Altherr, Lena and Ederer, Thorsten and Sch{\"a}nzle, Christian and Lorenz, Ulf and Pelz, Peter F.},
  title     = {Algorithmic system design using scaling and affinity laws},
  series = {Operations Research Proceedings 2015},
  booktitle = {Operations Research Proceedings 2015},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-42901-4},
  doi       = {10.1007/978-3-319-42902-1},
  pages     = {605 -- 611},
  year      = {2017},
  abstract  = {Energy-efficient components do not automatically lead to energy-efficient systems. Technical Operations Research (TOR) shifts the focus from the single component to the system as a whole and finds its optimal topology and operating strategy simultaneously. In previous works, we provided a preselected construction kit of suitable components for the algorithm. This approach may give rise to a combinatorial explosion if the preselection cannot be cut down to a reasonable number by human intuition. To reduce the number of discrete decisions, we integrate laws derived from similarity theory into the optimization model. Since the physical characteristics of a production series are similar, it can be described by affinity and scaling laws. Making use of these laws, our construction kit can be modeled more efficiently: Instead of a preselection of components, it now encompasses whole model ranges. This allows us to significantly increase the number of possible set-ups in our model. In this paper, we present how to embed this new formulation into a mixed-integer program and assess the run time via benchmarks. We present our approach on the example of a ventilation system design problem.},
  language  = {en}
}
@article{AltherrEdererLorenzetal.2014,
  author    = {Altherr, Lena and Ederer, Thorsten and Lorenz, Ulf and Pelz, Peter F. and P{\"o}ttgen, Philipp},
  title     = {Experimental validation of an enhanced system synthesis approach},
  series = {Operations Research Proceedings 2014},
  journal   = {Operations Research Proceedings 2014},
  editor    = {L{\"u}bbecke, Marco and Koster, Arie and Letmathe, Peter and Madlener, Reihard and Peis, Britta and Walther, Grit},
  publisher = {Springer},
  address   = {Basel},
  isbn      = {978-3-319-28695-2},
  doi       = {10.1007/978-3-319-28697-6_1},
  pages     = {6},
  year      = {2014},
  abstract  = {Planning the layout and operation of a technical system is a common task for an engineer. Typically, the workflow is divided into consecutive stages: First, the engineer designs the layout of the system, with the help of his experience or of heuristic methods. Secondly, he finds a control strategy which is often optimized by simulation. This usually results in a good operating of an unquestioned sys- tem topology. In contrast, we apply Operations Research (OR) methods to find a cost-optimal solution for both stages simultaneously via mixed integer program- ming (MILP). Technical Operations Research (TOR) allows one to find a provable global optimal solution within the model formulation. However, the modeling error due to the abstraction of physical reality remains unknown. We address this ubiq- uitous problem of OR methods by comparing our computational results with mea- surements in a test rig. For a practical test case we compute a topology and control strategy via MILP and verify that the objectives are met up to a deviation of 8.7\%.},
  language  = {en}
}
@inproceedings{EnglhardWeberArent2021,
  author    = {Englhard, Markus and Weber, Tobias and Arent, Jan-Christoph},
  title     = {Efficiency enhancement for CFRP-Prepregautoclave manufacturing by means of simulation-assisted loading optimization},
  series = {Proceedings of SAMPE Europe Conference 2021},
  booktitle = {Proceedings of SAMPE Europe Conference 2021},
  pages     = {8 Seiten},
  year      = {2021},
  abstract  = {A new method for improved autoclave loading within the restrictive framework of helicopter manufacturing is proposed. It is derived from experimental and numerical studies of the curing process and aims at optimizing tooling positions in the autoclave for fast and homogeneous heat-up. The mold positioning is based on two sets of information. The thermal properties of the molds, which can be determined via semi-empirical thermal simulation. The second information is a previously determined distribution of heat transfer coefficients inside the autoclave. Finally, an experimental proof of concept is performed to show a cycle time reduction of up to 31\% using the proposed methodology.},
  language  = {en}
}
@book{Pieper2021,
  author    = {Pieper, Martin},
  title     = {Quantum mechanics: Introduction to mathematical formulation},
  publisher = {Springer},
  address   = {Wiesbaden},
  isbn      = {978-3-658-32644-9},
  doi       = {10.1007/978-3-658-32645-6},
  pages     = {XIII, 33},
  year      = {2021},
  abstract  = {Anyone who has always wanted to understand the hieroglyphs on Sheldon's blackboard in the TV series The Big Bang Theory or who wanted to know exactly what the fate of Schr{\"o}dinger's cat is all about will find a short, descriptive introduction to the world of quantum mechanics in this essential. The text particularly focuses on the mathematical description in the Hilbert space. The content goes beyond popular scientific presentations, but is nevertheless suitable for readers without special prior knowledge thanks to the clear examples.},
  language  = {en}
}
@inproceedings{KernImaniVashianiTimmermanns2021,
  author    = {Kern, Alexander and Imani Vashiani, Anahita and Timmermanns, Tobias},
  title     = {Threat for human beings due to touch voltages and body currents caused by direct lightning strikes in case of non-isolated lightning protection systems using natural components},
  series = {35th International Conference on Lightning Protection (ICLP) and XVI International Symposium on Lightning Protection (SIPDA)},
  booktitle = {35th International Conference on Lightning Protection (ICLP) and XVI International Symposium on Lightning Protection (SIPDA)},
  publisher = {IEEE},
  isbn      = {978-1-6654-2346-5},
  doi       = {10.1109/ICLPandSIPDA54065.2021.9627465},
  pages     = {8 Seiten},
  year      = {2021},
  abstract  = {For typical cases of non-isolated lightning protection systems (LPS) the impulse currents are investigated which may flow through a human body directly touching a structural part of the LPS. Based on a basic LPS model with conventional down-conductors especially the cases of external and internal steel columns and metal fa{\c{c}}ades are considered and compared. Numerical simulations of the line quantities voltages and currents in the time domain are performed with an equivalent circuit of the entire LPS. As a result it can be stated that by increasing the number of conventional down-conductors and external steel columns the threat for a human being can indeed be reduced, but not down to an acceptable limit. In case of internal steel columns used as natural down-conductors the threat can be reduced sufficiently, depending on the low-resistive connection of the steel columns to the lightning equipotential bonding or the earth termination system, resp. If a metal fa{\c{c}}ade is used the threat for human beings touching is usually very low, if the fa{\c{c}}ade is sufficiently interconnected and multiply connected to the lightning equipotential bonding or the earth termination system, resp.},
  language  = {en}
}
@article{GrundlachBaumannEngelmann2021,
  author    = {Grundlach, Michael and Baumann, Martin and Engelmann, Ulrich M.},
  title     = {How Multimodal Examinations Can Increase Sustainable Student Gain by Aligning Teaching and Assessment},
  series = {Current Directions in Biomedical Engineering},
  volume    = {7},
  journal   = {Current Directions in Biomedical Engineering},
  number    = {7/2},
  editor    = {D{\"o}ssel, Olaf},
  publisher = {De Gruyter},
  address   = {Berlin},
  isbn      = {2364-5504},
  doi       = {10.1515/cdbme-2021-2019},
  pages     = {73 -- 76},
  year      = {2021},
  abstract  = {Modern industry and multi-discipline projects require highly trained individuals with resilient science and engineering back-grounds. Graduates must be able to agilely apply excellent theoretical knowledge in their subject matter as well as essential practical "hands-on" knowledge of diverse working processes to solve complex problems. To meet these demands, university education follows the concept of Constructive Alignment and thus increasingly adopts the teaching of necessary practical skills to the actual industry requirements and assessment routines. However, a systematic approach to coherently align these three central teaching demands is strangely absent from current university curricula. We demonstrate the feasibility of implementing practical assessments in a regular theory-based examination, thus defining the term "blended assessment". We assessed a course for natural science and engineering students pursuing a career in biomedical engineering, and evaluated the benefit of blended assessment exams for students and lecturers. Our controlled study assessed the physiological background of electrocardiograms (ECGs), the practical measurement of ECG curves, and their interpretation of basic pathologic alterations. To study on long time effects, students have been assessed on the topic twice with a time lag of 6 months. Our findings suggest a significant improvement in student gain with respect to practical skills and theoretical knowledge. The results of the reassessments support these outcomes. From the lecturers' point of view, blended assessment complements practical training courses while keeping organizational effort manageable. We consider blended assessment a viable tool for providing an improved student gain, industry-ready education format that should be evaluated and established further to prepare university graduates optimally for their future careers.},
  language  = {en}
}
@article{WerfelGuenthnerHapfelmeieretal.2022,
  author    = {Werfel, Stanislas and G{\"u}nthner, Roman and Hapfelmeier, Alexander and Hanssen, Henner and Kotliar, Konstantin and Heemann, Uwe and Schmaderer, Christoph},
  title     = {Identification of cardiovascular high-risk groups from dynamic retinal vessel signals using untargeted machine learning},
  series = {Cardiovascular Research},
  volume    = {118},
  journal   = {Cardiovascular Research},
  number    = {2},
  editor    = {Guzik, Tomasz J.},
  publisher = {Oxford University Press},
  address   = {Oxford},
  issn      = {0008-6363},
  doi       = {10.1093/cvr/cvab040},
  pages     = {612 -- 621},
  year      = {2022},
  abstract  = {Dynamic retinal vessel analysis (DVA) provides a non-invasive way to assess microvascular function in patients and potentially to improve predictions of individual cardiovascular (CV) risk. The aim of our study was to use untargeted machine learning on DVA in order to improve CV mortality prediction and identify corresponding response alterations.},
  language  = {en}
}
@article{AlbannaConzenWeissetal.2021,
  author    = {Albanna, Walid and Conzen, Catharina and Weiss, Miriam and Seyfried, Katharina and Kotliar, Konstantin and Schmidt, Tobias Philip and Kuerten, David and Hescheler, J{\"u}rgen and Bruecken, Anne and Schmidt-Trucks{\"a}ss, Arno and Neumaier, Felix and Wiesmann, Martin and Clusmann, Hans and Schubert, Gerrit Alexander},
  title     = {Non-invasive assessment of neurovascular coupling after aneurysmal subarachnoid hemorrhage: a prospective observational trial using retinal vessel analysis},
  series = {Frontiers in Neurology},
  volume    = {12},
  journal   = {Frontiers in Neurology},
  number    = {12},
  issn      = {1664-2295},
  doi       = {10.3389/fneur.2021.690183},
  pages     = {1 -- 15},
  year      = {2021},
  abstract  = {Delayed cerebral ischemia (DCI) is a common complication after aneurysmal subarachnoid hemorrhage (aSAH) and can lead to infarction and poor clinical outcome. The underlying mechanisms are still incompletely understood, but animal models indicate that vasoactive metabolites and inflammatory cytokines produced within the subarachnoid space may progressively impair and partially invert neurovascular coupling (NVC) in the brain. Because cerebral and retinal microvasculature are governed by comparable regulatory mechanisms and may be connected by perivascular pathways, retinal vascular changes are increasingly recognized as a potential surrogate for altered NVC in the brain. Here, we used non-invasive retinal vessel analysis (RVA) to assess microvascular function in aSAH patients at different times after the ictus.},
  language  = {en}
}
@article{KuertenKotliarFuestetal.2021,
  author    = {Kuerten, David and Kotliar, Konstantin and Fuest, Matthias and Walter, Peter and Hollstein, Muriel and Plange, Niklas},
  title     = {Does hemispheric vascular regulation differ significantly in glaucoma patients with altitudinal visual field asymmetry? A single-center, prospective study},
  series = {International Ophthalmology},
  volume    = {41},
  journal   = {International Ophthalmology},
  number    = {41},
  editor    = {Neri, Piergiorgio},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {1573-2630},
  doi       = {10.1007/s10792-021-01876-0},
  pages     = {3109 -- 3119},
  year      = {2021},
  abstract  = {Purpose Vascular risk factors and ocular perfusion are heatedly discussed in the pathogenesis of glaucoma. The retinal vessel analyzer (RVA, IMEDOS Systems, Germany) allows noninvasive measurement of retinal vessel regulation. Significant differences especially in the veins between healthy subjects and patients suffering from glaucoma were previously reported. In this pilot-study we investigated if localized vascular regulation is altered in glaucoma patients with altitudinal visual field defect asymmetry. Methods 15 eyes of 12 glaucoma patients with advanced altitudinal visual field defect asymmetry were included. The mean defect was calculated for each hemisphere separately (-20.99 ± 10.49 pro- found hemispheric visual field defect vs -7.36 ± 3.97 dB less profound hemisphere). After pupil dilation, RVA measurements of retinal arteries and veins were conducted using the standard protocol. The superior and inferior retinal vessel reactivity were measured consecutively in each eye. Results Significant differences were recorded in venous vessel constriction after flicker light stimulation and overall amplitude of the reaction (p \ 0.04 and p \ 0.02 respectively) in-between the hemispheres spheres. Vessel reaction was higher in the hemisphere corresponding to the more advanced visual field defect. Arterial diameters reacted similarly, failing to reach statistical significance. Conclusion Localized retinal vessel regulation is significantly altered in glaucoma patients with asymmetri altitudinal visual field defects. Veins supplying the hemisphere concordant to a less profound visual field defect show diminished diameter changes. Vascular dysregulation might be particularly important in early glaucoma stages prior to a significant visual field defect.},
  language  = {en}
}
@incollection{Kotliar2021,
  author    = {Kotliar, Konstantin},
  title     = {Ocular rigidity: clinical approach},
  series = {Ocular Rigidity, Biomechanics and Hydrodynamics of the Eye},
  booktitle = {Ocular Rigidity, Biomechanics and Hydrodynamics of the Eye},
  editor    = {Pallikaris, I. and Tsilimbaris, M. K. and Dastiridou, A. I.},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-030-64422-2},
  doi       = {10.1007/978-3-030-64422-2_2},
  pages     = {15 -- 43},
  year      = {2021},
  abstract  = {The term ocular rigidity is widely used in clinical ophthalmology. Generally it is assumed as a resistance of the whole eyeball to mechanical deformation and relates to biomechanical properties of the eye and its tissues. Basic principles and formulas for clinical tonometry, tonography and pulsatile ocular blood flow measurements are based on the concept of ocular rigidity. There is evidence for altered ocular rigidity in aging, in several eye diseases and after eye surgery. Unfortunately, there is no consensual view on ocular rigidity: it used to make a quite different sense for different people but still the same name. Foremost there is no clear consent between biomechanical engineers and ophthalmologists on the concept. Moreover ocular rigidity is occasionally characterized using various parameters with their different physical dimensions. In contrast to engineering approach, clinical approach to ocular rigidity claims to characterize the total mechanical response of the eyeball to its deformation without any detailed considerations on eye morphology or material properties of its tissues. Further to the previous chapter this section aims to describe clinical approach to ocular rigidity from the perspective of an engineer in an attempt to straighten out this concept, to show its advantages, disadvantages and various applications.},
  language  = {en}
}
@incollection{AltherrEdererLorenzetal.2016,
  author    = {Altherr, Lena and Ederer, Thorsten and Lorenz, Ulf and Pelz, Peter F. and P{\"o}ttgen, Philipp},
  title     = {Designing a feedback control system via mixed-integer programming},
  series = {Operations Research Proceedings 2014: Selected Papers of the Annual International Conference of the German Operations Research},
  booktitle = {Operations Research Proceedings 2014: Selected Papers of the Annual International Conference of the German Operations Research},
  editor    = {L{\"u}bbecke, Marco E. and Koster, Arie and Letmathe, Peter and Madlener, Reihard and Preis, Britta and Walther, Grit},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-28695-2},
  doi       = {10.1007/978-3-319-28697-6_18},
  pages     = {121 -- 127},
  year      = {2016},
  abstract  = {Pure analytical or experimental methods can only find a control strategy for technical systems with a fixed setup. In former contributions we presented an approach that simultaneously finds the optimal topology and the optimal open-loop control of a system via Mixed Integer Linear Programming (MILP). In order to extend this approach by a closed-loop control we present a Mixed Integer Program for a time discretized tank level control. This model is the basis for an extension by combinatorial decisions and thus for the variation of the network topology. Furthermore, one is able to appraise feasible solutions using the global optimality gap.},
  language  = {en}
}
@book{Altherr2016,
  author    = {Altherr, Lena},
  title     = {Algorithmic System Design under Consideration of Dynamic Processes},
  publisher = {Shaker},
  address   = {Aachen},
  isbn      = {978-3-8440-4848-3},
  pages     = {94},
  year      = {2016},
  abstract  = {Nach Stand von Wissenschaft und Technik werden Komponenten hinsichtlich ihrer Eigenschaften, wie Lebensdauer oder Energieeffizienz, optimiert. Allerdings k{\"o}nnen selbst hervorragende Komponenten zu ineffizienten oder instabilen Systemen f{\"u}hren, wenn ihr Zusammenspiel nur unzureichend ber{\"u}cksichtigt wird. Eine Systembetrachtung schafft ein gr{\"o}ßeres Optimierungspotential - dem erh{\"o}hten Potential steht jedoch auch ein erh{\"o}hter Komplexit{\"a}tsgrad gegen{\"u}ber. Die vorliegende Arbeit ist im Rahmen des Sonderforschungsbereichs 805 entstanden, dessen Ziel die Beherrschung von Unsicherheit in Systemen des Maschinenbaus ist. Die Arbeit zeigt anhand eines realen Systems aus dem Bereich der Hydraulik, wie Unsicherheit in der Entwicklungsphase beherrscht werden kann. Hierbei ist neu, dass die durch den sp{\"a}teren Betrieb zu erwartende Systemdegradation eines jeden m{\"o}glichen Systemvorschlags antizipiert werden kann. Dadurch k{\"o}nnen Betriebs- und Wartungskosten vorausgesagt und minimiert werden und durch eine optimale Betriebs- und Wartungsstrategie die Verf{\"u}gbarkeit des Systems garantiert werden. Wesentliche Fragen bei der optimalen Auslegung des betrachteten hydrostatischen Getriebes sind dessen physikalische Modellierung, die Darstellung des Optimierungsproblems als gemischt-ganzzahliges lineares Programm, und dessen algorithmische Behandlung zur L{\"o}sungsfindung. Hierzu werden Heuristiken zum schnelleren Auffinden sinnvoller Systemtopologien vorgestellt und mittels mathematischer Dekomposition eine Bewertung des dynamischen Verschleiß- und Wartungsverlaufs m{\"o}glicher Systemvorschl{\"a}ge vorgenommen. Die Arbeit stellt die Optimierung technischer Systeme an der Schnittstelle von Mathematik, Informatik und Ingenieurwesen sowohl gr{\"u}ndlich als auch anschaulich und nachvollziehbar dar.},
  language  = {en}
}
@inproceedings{RauschLeiseEdereretal.2016,
  author    = {Rausch, Lea and Leise, Philipp and Ederer, Thorsten and Altherr, Lena and Pelz, Peter F.},
  title     = {A comparison of MILP and MINLP solver performance on the example of a drinking water supply system design problem},
  series = {ECCOMAS Congress 2016 VII European Congress on Computational Methods in Applied Sciences and Engineering},
  booktitle = {ECCOMAS Congress 2016 VII European Congress on Computational Methods in Applied Sciences and Engineering},
  editor    = {Papadrakakis, M. and Ppadopoulos, V. and Stefanou, G. and Plevris, V.},
  isbn      = {978-618-82844-0-1},
  pages     = {8509 -- 8527},
  year      = {2016},
  abstract  = {Finding a good system topology with more than a handful of components is a highly non-trivial task. The system needs to be able to fulfil all expected load cases, but at the same time the components should interact in an energy-efficient way. An example for a system design problem is the layout of the drinking water supply of a residential building. It may be reasonable to choose a design of spatially distributed pumps which are connected by pipes in at least two dimensions. This leads to a large variety of possible system topologies. To solve such problems in a reasonable time frame, the nonlinear technical characteristics must be modelled as simple as possible, while still achieving a sufficiently good representation of reality. The aim of this paper is to compare the speed and reliability of a selection of leading mathematical programming solvers on a set of varying model formulations. This gives us empirical evidence on what combinations of model formulations and solver packages are the means of choice with the current state of the art.},
  language  = {en}
}
@inproceedings{RauschFriesenAltherretal.2018,
  author    = {Rausch, Lea and Friesen, John and Altherr, Lena and Pelz, Peter F.},
  title     = {Using mixed-integer programming for the optimal design of water supply networks for slums},
  series = {Operations Research Proceedings 2017},
  booktitle = {Operations Research Proceedings 2017},
  editor    = {Kliewer, Natalia and Ehmke, Jan Fabian and Bornd{\"o}rfer, Ralf},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-89919-0 (Print)},
  doi       = {10.1007/978-3-319-89920-6_68},
  pages     = {509 -- 516},
  year      = {2018},
  abstract  = {The UN sets the goal to ensure access to water and sanitation for all people by 2030. To address this goal, we present a multidisciplinary approach for designing water supply networks for slums in large cities by applying mathematical optimization. The problem is modeled as a mixed-integer linear problem (MILP) aiming to find a network describing the optimal supply infrastructure. To illustrate the approach, we apply it on a small slum cluster in Dhaka, Bangladesh.},
  language  = {en}
}
@incollection{LeiseAltherrPelz2018,
  author    = {Leise, Philipp and Altherr, Lena and Pelz, Peter F.},
  title     = {Energy-Efficient design of a water supply system for skyscrapers by mixed-integer nonlinear programming},
  series = {Operations Research Proceedings 2017},
  booktitle = {Operations Research Proceedings 2017},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-89919-0},
  doi       = {10.1007/978-3-319-89920-6_63},
  year      = {2018},
  abstract  = {The energy-efficiency of technical systems can be improved by a systematic design approach. Technical Operations Research (TOR) employs methods known from Operations Research to find a global optimal layout and operation strategy of technical systems. We show the practical usage of this approach by the systematic design of a decentralized water supply system for skyscrapers. All possible network options and operation strategies are modeled by a Mixed-Integer Nonlinear Program. We present the optimal system found by our approach and highlight the energy savings compared to a conventional system design.},
  language  = {en}
}
@inproceedings{LeiseAltherrPelz2018,
  author    = {Leise, Philipp and Altherr, Lena and Pelz, Peter F.},
  title     = {Technical Operations Research (TOR) - Algorithms, not Engineers, Design Optimal Energy Efficient and Resilient Cooling Systems},
  series = {FAN2018 - Proceedings of the International Conference on Fan Noise, Aerodynamics, Applications and Systems},
  booktitle = {FAN2018 - Proceedings of the International Conference on Fan Noise, Aerodynamics, Applications and Systems},
  pages     = {1 -- 12},
  year      = {2018},
  abstract  = {The overall energy efficiency of ventilation systems can be improved by considering not only single components, but by considering as well the interplay between every part of the system. With the help of the method "TOR" ("Technical Operations Research"), which was developed at the Chair of Fluid Systems at TU Darmstadt, it is possible to improve the energy efficiency of the whole system by considering all possible design choices programmatically. We show the ability of this systematic design approach with a ventilation system for buildings as a use case example. Based on a Mixed-Integer Nonlinear Program (MINLP) we model the ventilation system. We use binary variables to model the selection of different pipe diameters. Multiple fans are model with the help of scaling laws. The whole system is represented by a graph, where the edges represent the pipes and fans and the nodes represents the source of air for cooling and the sinks, that have to be cooled. At the beginning, the human designer chooses a construction kit of different suitable fans and pipes of different diameters and different load cases. These boundary conditions define a variety of different possible system topologies. It is not possible to consider all topologies by hand. With the help of state of the art solvers, on the other side, it is possible to solve this MINLP. Next to this, we also consider the effects of malfunctions in different components. Therefore, we show a first approach to measure the resilience of the shown example use case. Further, we compare the conventional approach with designs that are more resilient. These more resilient designs are derived by extending the before mentioned model with further constraints, that consider explicitly the resilience of the overall system. We show that it is possible to design resilient systems with this method already in the early design stage and compare the energy efficiency and resilience of these different system designs.},
  language  = {en}
}
@incollection{StengerAltherrMuelleretal.2018,
  author    = {Stenger, David and Altherr, Lena and M{\"u}ller, Tankred and Pelz, Peter F.},
  title     = {Product family design optimization using model-based engineering techniques},
  series = {Operations Research Proceedings 2017},
  booktitle = {Operations Research Proceedings 2017},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-89919-0},
  doi       = {10.1007/978-3-319-89920-6_66},
  pages     = {495 -- 502},
  year      = {2018},
  abstract  = {Highly competitive markets paired with tremendous production volumes demand particularly cost efficient products. The usage of common parts and modules across product families can potentially reduce production costs. Yet, increasing commonality typically results in overdesign of individual products. Multi domain virtual prototyping enables designers to evaluate costs and technical feasibility of different single product designs at reasonable computational effort in early design phases. However, savings by platform commonality are hard to quantify and require detailed knowledge of e.g. the production process and the supply chain. Therefore, we present and evaluate a multi-objective metamodel-based optimization algorithm which enables designers to explore the trade-off between high commonality and cost optimal design of single products.},
  language  = {en}
}
@inproceedings{LeiseAltherr2018,
  author    = {Leise, Philipp and Altherr, Lena},
  title     = {Optimizing the design and control of decentralized water supply systems - a case-study of a hotel building},
  series = {EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization},
  booktitle = {EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-97773-7},
  doi       = {10.1007/978-3-319-97773-7_107},
  pages     = {1241 -- 1252},
  year      = {2018},
  abstract  = {To increase pressure to supply all floors of high buildings with water, booster stations, normally consisting of several parallel pumps in the basement, are used. In this work, we demonstrate the potential of a decentralized pump topology regarding energy savings in water supply systems of skyscrapers. We present an approach, based on Mixed-Integer Nonlinear Programming, that allows to choose an optimal network topology and optimal pumps from a predefined construction kit comprising different pump types. Using domain-specific scaling laws and Latin Hypercube Sampling, we generate different input sets of pump types and compare their impact on the efficiency and cost of the total system design. As a realistic application example, we consider a hotel building with 325 rooms, 12 floors and up to four pressure zones.},
  language  = {en}
}
@article{SunAltherrPeietal.2018,
  author    = {Sun, Hui and Altherr, Lena and Pei, Ji and Pelz, Peter F. and Yuan, Shouqi},
  title     = {Optimal booster station design and operation under uncertain load},
  series = {Applied Mechanics and Materials},
  volume    = {885},
  journal   = {Applied Mechanics and Materials},
  publisher = {Trans Tech Publications},
  address   = {B{\"a}ch},
  issn      = {1662-7482},
  doi       = {10.4028/www.scientific.net/AMM.885.102},
  pages     = {102 -- 115},
  year      = {2018},
  abstract  = {Given industrial applications, the costs for the operation and maintenance of a pump system typically far exceed its purchase price. For finding an optimal pump configuration which minimizes not only investment, but life-cycle costs, methods like Technical Operations Research which is based on Mixed-Integer Programming can be applied. However, during the planning phase, the designer is often faced with uncertain input data, e.g. future load demands can only be estimated. In this work, we deal with this uncertainty by developing a chance-constrained two-stage (CCTS) stochastic program. The design and operation of a booster station working under uncertain load demand are optimized to minimize total cost including purchase price, operation cost incurred by energy consumption and penalty cost resulting from water shortage. We find optimized system layouts using a sample average approximation (SAA) algorithm, and analyze the results for different risk levels of water shortage. By adjusting the risk level, the costs and performance range of the system can be balanced, and thus the system's resilience can be engineered},
  language  = {en}
}
@article{AltherrJoggerstLeiseetal.2018,
  author    = {Altherr, Lena and Joggerst, Laura and Leise, Philipp and Pfetsch, Marc E. and Schmitt, Andreas and Wendt, Janine},
  title     = {On obligations in the development process of resilient systems with algorithmic design methods},
  series = {Applied Mechanics and Materials},
  volume    = {885},
  journal   = {Applied Mechanics and Materials},
  number    = {885},
  publisher = {Trans Tech Publications},
  address   = {B{\"a}ch},
  isbn      = {1662-7482},
  doi       = {10.4028/www.scientific.net/AMM.885.240},
  pages     = {240 -- 252},
  year      = {2018},
  abstract  = {Advanced computational methods are needed both for the design of large systems and to compute high accuracy solutions. Such methods are efficient in computation, but the validation of results is very complex, and highly skilled auditors are needed to verify them. We investigate legal questions concerning obligations in the development phase, especially for technical systems developed using advanced methods. In particular, we consider methods of resilient and robust optimization. With these techniques, high performance solutions can be found, despite a high variety of input parameters. However, given the novelty of these methods, it is uncertain whether legal obligations are being met. The aim of this paper is to discuss if and how the choice of a specific computational method affects the developer's product liability. The review of legal obligations in this paper is based on German law and focuses on the requirements that must be met during the design and development process.},
  language  = {en}
}
@inproceedings{MuellerAltherrAholaetal.2019,
  author    = {M{\"u}ller, Tim M. and Altherr, Lena and Ahola, Marja and Schabel, Samuel and Pelz, Peter F.},
  title     = {Multi-Criteria optimization of pressure screen systems in paper recycling - balancing quality, yield, energy consumption and system complexity},
  series = {EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization},
  booktitle = {EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization},
  editor    = {Rodrigues, H. C.},
  publisher = {Springer International Publishing},
  address   = {Basel},
  isbn      = {978-3-319-97773-7},
  doi       = {10.1007/978-3-319-97773-7_105},
  year      = {2019},
  abstract  = {The paper industry is the industry with the third highest energy consumption in the European Union. Using recycled paper instead of fresh fibers for papermaking is less energy consuming and saves resources. However, adhesive contaminants in recycled paper are particularly problematic since they reduce the quality of the resulting paper-product. To remove as many contaminants and at the same time obtain as many valuable fibres as possible, fine screening systems, consisting of multiple interconnected pressure screens, are used. Choosing the best configuration is a non-trivial task: The screens can be interconnected in several ways, and suitable screen designs as well as operational parameters have to be selected. Additionally, one has to face conflicting objectives. In this paper, we present an approach for the multi-criteria optimization of pressure screen systems based on Mixed-Integer Nonlinear Programming. We specifically focus on a clear representation of the trade-off between different objectives.},
  language  = {en}
}
@article{RauschFriesenAltherretal.2018,
  author    = {Rausch, Lea and Friesen, John and Altherr, Lena and Meck, Marvin and Pelz, Peter F.},
  title     = {A holistic concept to design optimal water supply infrastructures for informal settlements using remote sensing data},
  series = {Remote Sensing},
  volume    = {10},
  journal   = {Remote Sensing},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  isbn      = {2072-4292},
  doi       = {10.3390/rs10020216},
  pages     = {1 -- 23},
  year      = {2018},
  abstract  = {Ensuring access to water and sanitation for all is Goal No. 6 of the 17 UN Sustainability Development Goals to transform our world. As one step towards this goal, we present an approach that leverages remote sensing data to plan optimal water supply networks for informal urban settlements. The concept focuses on slums within large urban areas, which are often characterized by a lack of an appropriate water supply. We apply methods of mathematical optimization aiming to find a network describing the optimal supply infrastructure. Hereby, we choose between different decentral and central approaches combining supply by motorized vehicles with supply by pipe systems. For the purposes of illustration, we apply the approach to two small slum clusters in Dhaka and Dar es Salaam. We show our optimization results, which represent the lowest cost water supply systems possible. Additionally, we compare the optimal solutions of the two clusters (also for varying input parameters, such as population densities and slum size development over time) and describe how the result of the optimization depends on the entered remote sensing data.},
  language  = {en}
}
@inproceedings{LorenzAltherrPelz2019,
  author    = {Lorenz, Imke-Sophie B. and Altherr, Lena and Pelz, Peter F.},
  title     = {Graph-theoretic resilience analysis of a water distribution system's topology},
  series = {World Congress on Resilience, Reliability and Asset Management 2019},
  booktitle = {World Congress on Resilience, Reliability and Asset Management 2019},
  pages     = {106 -- 109},
  year      = {2019},
  abstract  = {Water suppliers are faced with the great challenge of achieving high-quality and, at the same time, low-cost water supply. In practice, the focus is set on the most beneficial maintenance measures and/or capacity adaptations of existing water distribution systems (WDS). Since climatic and demographic influences will pose further challenges in the future, the resilience enhancement of WDS, i.e. the enhancement of their capability to withstand and recover from disturbances, has been in particular focus recently. To assess the resilience of WDS, metrics based on graph theory have been proposed. In this study, a promising approach is applied to assess the resilience of the WDS for a district in a major German City. The conducted analysis provides insight into the process of actively influencing the resilience of WDS},
  language  = {en}
}
@inproceedings{LeiseBreuerAltherretal.2020,
  author    = {Leise, Philipp and Breuer, Tim and Altherr, Lena and Pelz, Peter F.},
  title     = {Development, validation and assessment of a resilient pumping system},
  series = {Proceedings of the Joint International Resilience Conference, JIRC2020},
  booktitle = {Proceedings of the Joint International Resilience Conference, JIRC2020},
  isbn      = {978-90-365-5095-6},
  pages     = {97 -- 100},
  year      = {2020},
  abstract  = {The development of resilient technical systems is a challenging task, as the system should adapt automatically to unknown disturbances and component failures. To evaluate different approaches for deriving resilient technical system designs, we developed a modular test rig that is based on a pumping system. On the basis of this example system, we present metrics to quantify resilience and an algorithmic approach to improve resilience. This approach enables the pumping system to automatically react on unknown disturbances and to reduce the impact of component failures. In this case, the system is able to automatically adapt its topology by activating additional valves. This enables the system to still reach a minimum performance, even in case of failures. Furthermore, timedependent disturbances are evaluated continuously, deviations from the original state are automatically detected and anticipated in the future. This allows to reduce the impact of future disturbances and leads to a more resilient system behaviour.},
  language  = {en}
}
@article{LeiseEsserEichenlaubetal.2021,
  author    = {Leise, Philipp and Eßer, Arved and Eichenlaub, Tobias and Schleiffer, Jean-Eric and Altherr, Lena and Rinderknecht, Stephan and Pelz, Peter F.},
  title     = {Sustainable system design of electric powertrains - comparison of optimization methods},
  series = {Engineering Optimization},
  journal   = {Engineering Optimization},
  publisher = {Taylor \& Francis},
  address   = {London},
  issn      = {0305-215X},
  doi       = {10.1080/0305215X.2021.1928660},
  year      = {2021},
  abstract  = {The transition within transportation towards battery electric vehicles can lead to a more sustainable future. To account for the development goal 'climate action' stated by the United Nations, it is mandatory, within the conceptual design phase, to derive energy-efficient system designs. One barrier is the uncertainty of the driving behaviour within the usage phase. This uncertainty is often addressed by using a stochastic synthesis process to derive representative driving cycles and by using cycle-based optimization. To deal with this uncertainty, a new approach based on a stochastic optimization program is presented. This leads to an optimization model that is solved with an exact solver. It is compared to a system design approach based on driving cycles and a genetic algorithm solver. Both approaches are applied to find efficient electric powertrains with fixed-speed and multi-speed transmissions. Hence, the similarities, differences and respective advantages of each optimization procedure are discussed.},
  language  = {en}
}
@inproceedings{Huening2021,
  author    = {H{\"u}ning, Felix},
  title     = {Sustainable changes beyond covid-19 for a second semester physics course for electrical engineering students},
  series = {Blended Learning in Engineering Education: challenging, enlightening - and lasting?},
  booktitle = {Blended Learning in Engineering Education: challenging, enlightening - and lasting?},
  isbn      = {978-2-87352-023-6},
  pages     = {1405 -- 1409},
  year      = {2021},
  abstract  = {The course Physics for Electrical Engineering is part of the curriculum of the bachelor program Electrical Engineering at University of Applied Science Aachen. Before covid-19 the course was conducted in a rather traditional way with all parts (lecture, exercise and lab) face-to-face. This teaching approach changed fundamentally within a week when the covid-19 limitations forced all courses to distance learning. All parts of the course were transformed to pure distance learning including synchronous and asynchronous parts for the lecture, live online-sessions for the exercises and self-paced labs at home. Using these methods, the course was able to impart the required knowledge and competencies. Taking the teacher's observations of the student's learning behaviour and engagement, the formal and informal feedback of the students and the results of the exams into account, the new methods are evaluated with respect to effectiveness, sustainability and suitability for competence transfer. Based on this analysis strong and weak points of the concept and countermeasures to solve the weak points were identified. The analysis further leads to a sustainable teaching approach combining synchronous and asynchronous parts with self-paced learning times that can be used in a very flexible manner for different learning scenarios, pure online, hybrid (mixture of online and presence times) and pure presence teaching.},
  language  = {en}
}
@inproceedings{UlmerBraunChengetal.2021,
  author    = {Ulmer, Jessica and Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg},
  title     = {Adapting Augmented Reality Systems to the users' needs using Gamification and error solving methods},
  series = {Procedia CIRP},
  volume    = {104},
  booktitle = {Procedia CIRP},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2212-8271},
  doi       = {10.1016/j.procir.2021.11.024},
  pages     = {140 -- 145},
  year      = {2021},
  abstract  = {Animations of virtual items in AR support systems are typically predefined and lack interactions with dynamic physical environments. AR applications rarely consider users' preferences and do not provide customized spontaneous support under unknown situations. This research focuses on developing adaptive, error-tolerant AR systems based on directed acyclic graphs and error resolving strategies. Using this approach, users will have more freedom of choice during AR supported work, which leads to more efficient workflows. Error correction methods based on CAD models and predefined process data create individual support possibilities. The framework is implemented in the Industry 4.0 model factory at FH Aachen.},
  language  = {en}
}