@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}
}