@phdthesis{Rizzi2024, author = {Rizzi, Tommaso}, title = {Investigation of the different abstraction levels for the design of RRAM-based systems}, doi = {10.26127/BTUOpen-6867}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68677}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {The great capabilities of modern electronics have brought in any aspect of our life innovations that were inconceivable before. This progress is enabled by a microelectronic market in continuous evolution, where novel solutions are introduced in order to fulfil the increasing requirements in terms of computing speed, energy efficiency, and area miniaturization. Among the various possibilities under the spotlight for thrusting the performance advancement in the next generation of computing systems, major chip manufacturers are carefully investigating emerging Non-Volatile Memory (eNVM) technologies, in particular Resistive Random Access Memory (RRAM). While it was originally studied as an alternative non-volatile memory medium, the research community has soon realized how this family of devices with their tunable resistance can lead to new efficient designs in a variety of applications. The protagonist of the renewed enthusiasm for this technology is the thriving Artificial Intelligence (AI) field, where RRAM can support the fabrication of analogue accelerators. More precisely, the dual nature of an RRAM array as memory block and computing unit has the potential to implement novel hardware solutions that take inspiration from the human brain to efficiently execute Artificial Neural Networks (ANNs). However, the establishment of RRAM devices in the customer market is delayed by the on-going research to optimize the fabrication process. The contrast between the unsettled underlying hardware and the great interest toward emerging RRAM-based designs resulted in a performance gap between the envisioned RRAM systems and the prototyped ones. In order to transition the RRAM technology from the academic research to real-world scenarios, more circuits need to be designed, implemented, and tested. At the same time, the complexity and cost of modern electronics production impose high reliability and performance standard on the fabricated chip that can only be met by a tight link between the circuit-level validation and any stage of the design development. Unfortunately, the available tools to support the designer at the application- and system-level do not generally offer this cross-layer interface. This work investigates how important the electrical validation can be to guide the designer by comparing the circuital reliability aspects of a traditional routing component and an alternative RRAM-based implementation. Moreover, two different approaches are proposed to bridge the gap between the electric domain and the higher abstraction layers. First, SystemC-AMS is analysed as a viable option to include analogue simulations in Electronic System Level (ESL) evaluation. Several optimization techniques are also proposed to improve the framework performance. Finally, a Pytorch/Spectre tool-chain is implemented to enable circuit-level co-simulation during the testing of ANN models. The tool-chain is validated by considering the end-to-end accuracy for two classification tasks, namely MNIST and CIFAR10 datasets.}, subject = {RRAM; Multiplexer; SystemC; In-Memory Computing; Artificial Neural Network; Resistiver Direktzugriffsspeicher; Rechnen im Speicher; K{\"u}nstliches Neuronales Netzwerk (KNN); Resistive RAM; Routing; Neuronales Netz; Entwicklung; Simulation}, language = {en} } @phdthesis{Suetbaş2024, author = {S{\"u}tba{\c{s}}, Batuhan}, title = {61 GHz ultra-low-power chipset in 130-nm SiGe BiCMOS technology for CW radar applications}, doi = {10.26127/BTUOpen-6871}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68715}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Advances in the semiconductor technology and RF integrated circuits have been the main driver in broadening the diverse field of applications for CW radars. High performance millimeter-wave chipsets are proven essential and viable for realizing complex sensors. Nevertheless, the supply voltage and dc power consumption requirements remain a major impediment to achieve battery-powered operation and energy-efficient scalable MIMO solutions. This thesis presents the system- and circuit-level design considerations, implementation, and demonstration of a low-voltage and ultra-low-power chipset at 61 GHz to take the unprecedented step for enabling highly efficient radar sensors. A system-level study is conducted initially to link a medical radar application to circuit-level specifications. Novel building block circuits have been introduced to operate with the reduced supply voltage and current without compromising the target performance and functionality. The developed blocks are used to realize fully integrated VCO and TRX chips that are fabricated in IHP SG13G2 130-nm SiGe BiCMOS technology and verified individually on-wafer. The presented ultra-low-power chipset is employed in a radar demonstrator board and validated in laboratory environment for human vital signs detection. In addition, two methods are proposed to undertake the dc offset problem and are verified with measurements. The millimeter-wave chipset established by this work stands out with the reduced supply voltage and minimized dc power consumption compared to the state of the art. The scalable aspects of the proposed chipset support energy-efficient, battery-powered, and portable MIMO operation which are promising highlights for many future applications.}, subject = {Continuous-wave radar; Low-power; Low-voltage; Millimeter-wave; Silicon-germanium; Dauerstrichradar; Leistungseffizient; Niedrige Spannung; Millimeterwellen; Silizium-Germanium; Dauerstrichradar; Radarsensor; Chip; Millimeterwelle; Effizienz; Versorgungsspannung; Elektrizit{\"a}tsverbrauch; VCO; MIMO}, language = {en} } @phdthesis{Richter2024, author = {Richter, Lukas}, title = {Formulierung eines kontinuumsthermomechanischen Ansatzes zur FE-Modellierung von ratenabh{\"a}ngigen Materialverhalten unter Ber{\"u}cksichtigung von Sch{\"a}digungseffekten}, doi = {10.26127/BTUOpen-6868}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68680}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Additiv gefertigte Materialien erm{\"o}glichen im Bereich der Bauteilkonstruktion die Umsetzung von komplexen Geometrien. Mit den Prozessparametern kann zus{\"a}tzlich die finale Mikrostruktur des Materials beeinflusst werden. Das Beispiel der Aluminiumlegierung AlSi10 Mg zeigt, dass anhand von optimierten Prozessparametern ein zu den konventionell hergestellten Materialien vergleichbares mechanisches Verhalten zu erreichen ist. Aufgrund des sensitiven Verhaltens der mechanischen Eigenschaften gegen{\"u}ber {\"A}nderungen im Fertigungsprozess sind die sp{\"a}teren Bauteile vom Sch{\"a}digungsverhalten des Materials betroffen. Die vorliegende Arbeit verwendet daher f{\"u}r die numerische Beschreibung des Materialverhaltens von AlSi10 Mg ein gekoppeltes Chaboche-Gurson-Tvergaard-Needleman Modell und implementiert es {\"u}ber eine User Material Subroutine in das FE-Programm Abaqus. Dieser numerische Ansatz erm{\"o}glicht die Beschreibung eines ratenabh{\"a}ngigen Materialverhaltens unter Ber{\"u}cksichtigung von Sch{\"a}digungsmechanismen. Die vorliegende Dissertation entwickelt eine Methodik zur Parameteridentifizierung, die in eine Optimierungsaufgabe {\"u}bergeht. Zur Verbesserung der Zielfunktion wird das gekoppelte Chaboche-Gurson-Tvergaard-Needleman Modell um thermomechanische Ans{\"a}tze erweitert. Dadurch k{\"o}nnen aus thermomechanischen Experimenten neben der Spannungsantwort des Materials auch Temperatur{\"a}nderungen infolge mechanischer Deformationen erfasst werden. Die Optimierung erfolgt im Mathematikprogramm Matlab, wobei das thermomechanische Modell als adiabatisches System formuliert ist. F{\"u}r die Realisierung eines ann{\"a}hernd adiabaten Systemzustandes werden Versuche mit hohen Deformationsgeschwindigkeiten integriert. Weiterhin besch{\"a}ftigt sich diese Arbeit mit der Erweiterung des Gurson-Tvergaard-Needleman Modells um einen Ansatz, der den Einfluss von Schubspannungen auf das Sch{\"a}digungsverhalten des Materials ber{\"u}cksichtigt. F{\"u}r die Parameteridentifikation und die Validierung werden Zugversuche, Versuche mit geringen Spannungstriaxialit{\"a}ten und zyklische Versuche durchgef{\"u}hrt. Die Validierung der optimierten Parameter erfolgt durch FE-Berechnungen. Die Ergebnisse zeigen eine hohe Genauigkeit zur Darstellung des realen Materialverhaltens durch die Simulation.}, subject = {Thermomechanik; Chaboche; GTN; Sch{\"a}digung; Additive Fertigung; Thermomechanics; Chaboche; GTN; Damage; Additive Manufacturing; Rapid Prototyping ; Chaboche-Modell; Thermomechanik; Werkstoff; Sch{\"a}digung}, language = {de} } @phdthesis{BesongBesong2024, author = {Besong Besong, Lemopi Isidore}, title = {Development of novel hole-flanging processes}, doi = {10.26127/BTUOpen-6859}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68597}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Flanges are essential elements in sheet metal parts, where they perform important functions such as increasing structural stiffness, serve as bearing seats and positioning aids. Currently, flanges are mainly formed by the conventional hole-flanging process, which uses dedicated dies and punches. The limitations of conventional hole-flanging include the high cost involved in die design and manufacture, poor accessibility to form flanges in some complicated dies, and low formability. High-speed tool rotation is introduced in hole-flanging processes to increase the process temperature and forming limit of hard-to-form materials. This is done using paddle-shaped tools and spherical punches in existing production lines. In addition, strategies are explored to enhance the geometrical accuracy in robot-based hole-flanging by single-point incremental forming (SPIF). This thesis investigates new hole-flanging process variants by using experiments and finite element (FE) analysis. Empirical material models are used to study the effects of the process parameters on flange shape, forming limits, process temperature, and forming mechanics. The process formability is highest in hole-flanging with punch rotation and reduces for paddle forming and hole-flanging by SPIF. The least formability is observed in conventional hole-flanging. High-speed tool rotation and tool feeds form flanges with high formability. Surface strain measurements of the flanges show that low-speed tool rotation combined with high tool feeds favor crack formation. Tensile tests revealed that the material's formability increases with temperature and strain rate. From FE analyses of the process variants, the deformation in hole-flanging was determined to be mainly because of membrane stretching and bending. Some shear was present in paddle forming and SPIF. Based on FE analyses and experiments, the temperature and strain rate are determined to be the main parameters that account for the difference in process formability. Hole-flanging by SPIF is conducted on a robot manipulator to enhance geometrical accuracy. New tool paths are explored to prevent flange conicity. A parametric study is conducted to determine the process's feasibility. The stiffness of a robot is compensated to achieve the target flange geometry.}, subject = {Bohrungsflanschen; Hole-flanging; Paddle forming; Robot incremental forming; Process development; Deformation analysis; Schaufelumformung; Inkrementelle Roboterumformung; Verformungsanalyse; Prozessentwicklung; Kragenziehen; Flansch; Prozessentwicklung ; Deformation; Blechumformen; Finite-Elemente-Methode}, language = {en} } @phdthesis{JaramilloCajica2024, author = {Jaramillo Cajica, Ismael}, title = {A switched systems approach for voltage regulation in smart grids}, doi = {10.26127/BTUOpen-6873}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68734}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Smart grids provide state-of-the-art communication and information technologies that facilitate the integration of distributed generation units (DGUs) as well as the design of novel and flexible control strategies. In particular, the design of control strategies for DGUs in medium- and low-voltage (MV/LV) distribution microgrids, as well as for load tap changer transformers (LTCs) in extra high- and high-voltage (EHV/HV) transmission grids, is considered in this work. On the one hand, the DGUs are enabled to provide voltage control support by adopting a grid-aware operation paradigm, which allows them to autonomously switch between grid-forming and grid-feeding schemes whenever necessary. On the other hand, LTCs are equipped with a control strategy that imposes a coordinated sequence of discrete tap changes to ensure voltage regulation and prevent undesired transient phenomena. From a control systems perspective, ensuring stability in the presence of discontinuous phenomena, e.g., grid-aware switches and LTC taps, demands the explicit consideration of such features. Hence, the contributions of the present work are derived within the framework of switched systems theory and are characterized by the following aspects: (i) A passivity-based grid-feeding DGU controller is designed by taking inspiration from a similar grid-forming controller proposed in the literature. By taking this approach, stabilization results can be extended to microgrids with an arbitrary topology. (ii) A grid-aware DGU control strategy for autonomously switching between controllers is designed as a state- and time-dependent switching logic, which ensures that the closed-loop switched microgrid dynamics possesses a unique equilibrium point. (iii) Stability guarantees of the equilibrium point are provided by deriving sufficient tuning conditions for the control parameters via dwell-time methods within a multiple Lyapunov functions framework. The points (i)-(iii) are addressed separately for DC and AC microgrids. (iv) The discontinuous features of a class of LTC-controlled AC transmission grids are captured by a switched dynamic model. Based on this, a coordinated control strategy for LTCs is proposed, together with sufficient tuning conditions for its control parameters that ensure convergence of the regulated voltage and prevent undesired voltage oscillations known as voltage hunting. The viability of the abovementioned results is validated via illustrative simulation examples.}, subject = {Grid-aware control; Switched systems; Voltage hunting; Netzbewusste Regelung; Geschaltete Systeme; Intelligentes Stromnetz; Spannungsregelung; Schaltvorgang; Regelungssystem}, language = {en} } @phdthesis{Wolf2024, author = {Wolf, Adrian}, title = {Thermochemische Untersuchungen des Systems [C₄mim]Cl/AlCl₃ und ausgew{\"a}hlter Modellreaktionen}, doi = {10.26127/BTUOpen-6857}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68571}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {1-Butyl-3-methylimidazoliumchlorid in Kombination mit Aluminiumchlorid fand bereits bei vielen unterschiedlichen Synthesen Anwendung. Dennoch gibt es bisher wenig thermodynamische Daten zu diesem bin{\"a}ren System. Daher wurde mittels dynamischer Differenzkalorimetrie dieses System charakterisiert und das Phasendiagramm modelliert. Weiterhin wurden in der Literatur beschriebenen Synthesen in diesem Stoffsystem mit Hilfe der Mikroreaktionskalorimetrie analysiert. Diese kam hier erstmals zur Untersuchung ionischer Fl{\"u}ssigkeiten zum Einsatz. Dabei sollte {\"u}berpr{\"u}ft werden, ob sich verschiedene Teilvorg{\"a}nge, wie Phasenbildung oder Ausf{\"a}llen des Produkts, messtechnisch erfassen und quantifizieren lassen. Zur Erg{\"a}nzung beider thermochemischer Schwerpunkte wurden spektroskopische Methoden, dabei haupts{\"a}chlich die Ramanspektroskopie, eingesetzt. Es sollten die in der ionischen Fl{\"u}ssigkeit vorliegenden Spezies identifiziert werden, um R{\"u}ckschl{\"u}sse auf die ablaufenden Reaktionen ziehen zu k{\"o}nnen.}, subject = {Ionische Fl{\"u}ssigkeiten; Ionic liquids; Thermochemische Modellierung; Thermochemical modeling; Kalorimetrie; Calorimetry; 1-Butyl-3-methylimidazoliumchlorid; 1-butyl-3-methylimidazolium chloride; Phasendiagramm; Phase diagram; Thermochemie; Ionische Fl{\"u}ssigkeit; Mikrokalorimetrie; Differential scanning calorimetry; Phasendiagramm; Raman-Spektroskopie}, language = {de} } @techreport{ZellSchneidereitFuegenschuhetal.2024, type = {Working Paper}, author = {Zell, Sascha and Schneidereit, Toni and F{\"u}genschuh, Armin and Breuß, Michael}, title = {Advanced search and rescue operations for drowning swimmers using autonomous unmanned aircraft systems : location optimization, flight trajectory planning and image-based localization}, doi = {10.26127/BTUOpen-6866}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68669}, year = {2024}, abstract = {Drowning is among the most prevalent causes of death from unintentional injuries worldwide. Because of the time-sensitive nature of swimming accidents and the shortage of lifeguard staff resulting in unsupervised swimming areas, interest in supportive rescue methods increases. In this paper, we propose an autonomous Unmanned Aircraft System (UAS) usable by Emergency Medical Service (EMS) providers in swimmer rescue scenarios additionally to Standard Rescue Operation (SRO) equipment. The UAS consists of Unmanned Aerial Vehicles (UAVs) and purpose-built hangars located near the swimming area to store the UAVs. When receiving an alert, the UAVs autonomously navigate to the emergency site to conduct a Search and Rescue (S\&R) operation for the drowning person. We introduce a Mixed-Integer Linear Programming (MILP) model to address the Facility Location Problem (FLP), assisting with identification of accessibility-optimal UAV hangar placements near the swimming area. Additionally, we present a MILP model to optimize the UAV flight trajectories in advance of the operation, allowing for efficient coordination of a heterogeneous UAV fleet. We apply the presented MILP models to a real-world scenario in the Lusatian Lake District using the state-of-the-art commercial solver CPLEX to solve the instances. Furthermore, we present a method for automated image-based swimmer localization using the state-of-the-art neural network You Only Look Once (YOLO). Finally, we use a Discrete-Event Simulation (DES) approach to quantify how much time is saved by using additional resources.}, subject = {Unmanned Aerial Vehicle; Unmanned Aircraft System; Water Rescue; Mixed-Integer Linear Programming; You Only Look Once; Drohne; Drohnenhangar; Wasserrettung; Gemischt-ganzzahlige Programmierung; Standortoptimierung; Drohne ; Wasserrettung; Lineare Optimierung}, language = {en} } @misc{OPUS4-6778, title = {Amtliches Mitteilungsblatt der BTU Cottbus-Senftenberg, 2024, 34 (13.11.2024)}, doi = {10.26127/BTUOpen-6778}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-67780}, year = {2024}, abstract = {Beitragsordnung der Studierendenschaft der Brandenburgischen Technischen Universit{\"a}t Cottbus-Senftenberg vom 15. Oktober 2024 f{\"u}r das Sommersemester 2025 und Wintersemester 2025/2026}, language = {de} } @phdthesis{Sporleder2024, author = {Sporleder, Maximilian}, title = {Design optimization of decarbonized district heating systems}, doi = {10.26127/BTUOpen-6852}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68526}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Reducing CO₂ emissions is crucial to combat global warming, especially as district heating sector emissions have increased by 25 \% since 2010. This dissertation addresses the need for decarbonizing district heating systems through a Python package designed for optimizing sustainable heat solutions. It explores three main research questions: integrating renewable heat sources, modeling pit thermal energy storage systems, and comparing central supply networks with those incorporating booster heat pumps. The research includes a systematic literature review focused on optimizing district heating, identifying gaps in integrating renewable energy and storage capacities. A modeling approach to assess storage capacity within optimization problems is developed, along with a mixed-integer linear programming model for designing supply systems. The model considers network topology, demand, weather, and component data, optimizing mass flows and minimizing costs. Key findings indicate that integrating large-scale heat pumps and waste heat can compete economically with traditional systems. Pit thermal energy storage systems, particularly in high-temperature networks (>70 °C), can be designed effectively using mixed-integer linear programming combined with simulations. Charging strategies, such as solar thermal energy for low-density areas or Power-to-Heat technologies for urban settings, enhance economic performance. The study suggests that a combination of central and decentralized units, like booster heat pumps, can optimize performance and reduce investment costs. Overall, the research emphasizes the importance of integrating waste heat and thermal storage in creating decarbonized district heating systems that can supply heat for 15 ct/kWh by 2030.}, subject = {Design optimization; District heating; Mixed-integer linear programming; Auslegungsoptimierung; Gemischt-ganzzahlige lineare Optimierung; Fernw{\"a}rmesysteme; Fernw{\"a}rmeversorgung; Abw{\"a}rme; Großw{\"a}rmepumpe; W{\"a}rmespeicher; Ganzzahlige lineare Optimierung}, language = {en} } @article{HuberHeinrichsJaegerErben2024, author = {Huber, Andreas and Heinrichs, Harald and Jaeger-Erben, Melanie}, title = {Promoting neighbourhood sharing : infrastructures of convenience and community}, series = {Buildings \& Cities}, volume = {5}, journal = {Buildings \& Cities}, number = {1}, publisher = {Ubiquity Press}, address = {London}, issn = {2632-6655}, doi = {10.5334/bc.442}, pages = {349 -- 367}, year = {2024}, abstract = {Against the background of high levels of energy and resource demand in the residential sector, this paper investigates one potential way of making housing more sufficient: sharing at the neighbourhood level. Evidence from French and German case studies of 'collaborative housing' and 'developer-driven neighbourhood sharing' is used to identify two types of popular sharing practices: community-oriented and convenience-oriented. The first group of sharing practices is underpinned by creating, maintaining and experiencing social ties with neighbours. The second group of practices is guided by getting day-today tasks done smoothly and efficiently. To support the establishment of such sharing practices, some social and organisational measures are suggested. Thus, convenience-oriented sharing practices may be promoted by infrastructures and associated services that optimise the availability of sharing facilities and minimise temporal stretches and consumption work involved in practice performances. Community-oriented sharing practices may benefit from infrastructural arrangements that enable chance encounters, privilege community spaces over private areas and create welcoming spatial atmospheres.}, subject = {Housing; Sustainability; Neighbourhood; Sharing; Sufficiency; Wohnen; Nachbarschaft; Suffizienz; Nachhaltigkeit}, language = {en} } @article{RiedelMeissnerKaschubowskietal.2024, author = {Riedel, Ramona and Meißner, Karsten and Kaschubowski, Arne and Benndorf, Dirk and Martienssen, Marion and Braun, Burga}, title = {Laundry isolate Delftia sp. UBM14 capable of biodegrading industrially relevant aminophosphonates}, series = {Microorganisms}, volume = {12}, journal = {Microorganisms}, publisher = {MDPI}, address = {Basel}, issn = {2076-2607}, doi = {10.3390/microorganisms12081664}, year = {2024}, abstract = {Phosphonates such as ethylenediaminetetra (methylenephosphonic acid) (EDTMP) and aminotris (methylenephosphonic acid) (ATMP) are used every day in water treatment processes or in household products. Their consumption is still increasing, regardless of the debates on their environmental impact. Here, the microbial characterisation and determination of the biodegradation potential of selected industrially relevant phosphonates for the isolate Delftia sp. UMB14 is reported. The opportunistic strain was isolated from a biofilm that was derived from a conventional washing machine using conventional detergents containing phosphonates. In antimicrobial susceptibility testing, the strain was only susceptible to sulfonamide, tetracycline, and chloramphenicol. Physiological and biochemical characteristics were determined using the BIOLOG EcoPlate assay. Most importantly, the strain was shown to convert D-malic acid and D-mannitol, as confirmed for strains of Delftia lacustris, and thus the new isolate could be closely related. Biodegradation tests with different phosphonates showed that the strain preferentially degrades ATMP and EDTMP but does not degrade glyphosate (GS) and amino (methylphosphonic acid) (AMPA). A specific gene amplification confirmed the presence of phnX (phosphonoacetaldehyde hydrolase) and the absence of PhnJ (the gene for the core component of C-P lyase). The presence of PhnCDE is strongly suggested for the strain, as it is common in Delftia lacustris species.}, subject = {Phosphonates; Biodegradation; PhnX; PhnJ; PhnCDE; Phosphonate; Biologischer Abbau; Mikrobieller Abbau; Waschmittel}, language = {en} }