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In 2015, Google engineer Alexander Mordvintsev presented DeepDream as technique to visualise the feature analysis capabilities of deep neural networks that have been trained on image classification tasks. For a brief moment, this technique enjoyed some popularity among scientists, artists, and the general public because of its capability to create seemingly hallucinatory synthetic images. But soon after, research moved on to generative models capable of producing more diverse and more realistic synthetic images. At the same time, the means of interaction with these models have shifted away from a direct manipulation of algorithmic properties towards a predominance of high level controls that obscure the model's internal working. In this paper, we present research that returns to DeepDream to assess its suit-ability as method for sound synthesis. We consider this research to be necessary for two reasons: it tackles a perceived lack of research on musical applications of DeepDream, and it addresses DeepDream's potential to combine data driven and algorithmic approaches. Our research includes a study of how the model architecture, choice of audio data-sets, and method of audio processing influence the acoustic characteristics of the synthesised sounds. We also look into the potential application of DeepDream in a live-performance setting. For this reason, the study limits itself to models consisting of small neural networks that process time-domain representations of audio. These models are resource-friendly enough to operate in real time. We hope that the results obtained so far highlight the attractiveness of Deep-Dream for musical approaches that combine algorithmic investigation with curiosity driven and open ended exploration.
This paper describes the authors' first experiments in creating an artificial dancer whose movements are generated through a combination of algorithmic and interactive techniques with machine learning. This approach is inspired by the time honoured practice of puppeteering. In puppeteering, an articulated but inanimate object seemingly comes to live through the combined effects of a human controlling select limbs of a puppet while the rest of the puppet's body moves according to gravity and mechanics. In the approach described here, the puppet is a machine-learning-based artificial character that has been trained on motion capture recordings of a human dancer. A single limb of this character is controlled either manually or algorithmically while the machine-learning system takes over the role of physics in controlling the remainder of the character's body. But rather than imitating physics, the machine-learning system generates body movements that are reminiscent of the particular style and technique of the dancer who was originally recorded for acquiring training data. More specifically, the machine-learning system operates by searching for body movements that are not only similar to the training material but that it also considers compatible with the externally controlled limb. As a result, the character playing the role of a puppet is no longer passively responding to the puppeteer but makes movement decisions on its own. This form of puppeteering establishes a form of dialogue between puppeteer and puppet in which both improvise together, and in which the puppet exhibits some of the creative idiosyncrasies of the original human dancer.
Generative machine learning models for creative purposes play an increasingly prominent role in the field of dance and technology. A particularly popular approach is the use of such models for generating synthetic motions. Such motions can either serve as source of ideation for choreographers or control an artificial dancer that acts as improvisation partner for human dancers. Several examples employ autoencoder-based deep-learning architectures that have been trained on motion capture recordings of human dancers. Synthetic motions are then generated by navigating the autoencoder's latent space. This paper proposes an alternative approach of using an autoencoder for creating synthetic motions. This approach controls the generation of synthetic motions on the level of the motion itself rather than its encoding. Two different methods are presented that follow this principle. Both methods are based on the interactive control of a single joint of an artificial dancer while the other joints remain under the control of the autoencoder. The first method combines the control of the orientation of a joint with iterative autoencoding. The second method combines the control of the target position of a joint with forward kinematics and the application of latent difference vectors. As illustrative example of an artistic application, this latter method is used for an artificial dancer that plays a digital instrument. The paper presents the implementation of these two methods and provides some preliminary results.
Strings P
(2021)
Strings is an audiovisual performance for an acoustic violin and two generative instruments, one for creating synthetic sounds and one for creating synthetic imagery. The three instruments are related to each other conceptually , technically, and aesthetically by sharing the same physical principle, that of a vibrating string. This submission continues the work the authors have previously published at xCoAx 2020. The current submission briefly summarizes the previous publication and then describes the changes that have been made to Strings. The P in the title emphasizes, that most of these changes have been informed by experiences collected during rehearsals (in German Proben). These changes have helped Strings to progress from a predominantly technical framework to a work that is ready for performance.
Strings
(2020)
This article presents the currently ongoing development of an audiovisual performance work with the title Strings. This work provides an improvisation setting for a violinist, two laptop performers, and two generative systems. At the core of Strings lies an approach that establishes a strong correlation among all participants by means of a shared physical principle. The physical principle is that of a vibrating string. The article discusses how this principle is used in both natural and simulated forms as main interaction layer between all performers and as natural or generative principle for creating audio and video.
Variable refrigerant flow (VRF) and variable air volume (VAV) systems are considered among the best heating, ventilation, and air conditioning systems (HVAC) thanks to their ability to provide cooling and heating in different thermal zones of the same building. As well as their ability to recover the heat rejected from spaces requiring cooling and reuse it to heat another space. Nevertheless, at the same time, these systems are considered one of the most energy-consuming systems in the building. So, it is crucial to well size the system according to the building’s cooling and heating needs and the indoor temperature fluctuations. This study aims to compare these two energy systems by conducting an energy model simulation of a real building under a semi-arid climate for cooling and heating periods. The developed building energy model (BEM) was validated and calibrated using measured and simulated indoor air temperature and energy consumption data. The study aims to evaluate the effect of these HVAC systems on energy consumption and the indoor thermal comfort of the building. The numerical model was based on the Energy Plus simulation engine. The approach used in this paper has allowed us to reach significant quantitative energy saving along with a high level of indoor thermal comfort by using the VRF system compared to the VAV system. The findings prove that the VRF system provides 46.18% of the annual total heating energy savings and 6.14% of the annual cooling and ventilation energy savings compared to the VAV system.
The increasing diffusion of rapidly developing AI technologies led to the idea of the experiment to combine TRIZ-based automated idea generation with the natural language processing tool ChatGPT, using the chatbot to interpret the automatically generated elementary solution principles. The article explores the opportunities and benefits of a novel AI-enhanced approach to teaching systematic innovation, analyses the learning experience, identifies the factors that affect students' innovation and problem-solving performance, and highlights the main difficulties students face, especially in interdisciplinary problems.
Inner Congo
(2023)
This research-creation project, part of the DE\GLOBALIZE artistic research cycle presented at the #IFM2022 Conference, investigates the complexities of Congo violence, care, and colonialism. Drawing on Michel Serres' metaphor of the great estuaries, the study explores the topology of interactive documentaries, blending theory, emotion, and personal experiences. Accessible through the interactive web documentation at http://deglobalize.com, the platform offers a media-archaeological archive for speculative ethnography, enabling the forensic processing of single documents in line with actor-network theory.
Enhancing engineering creativity with automated formulation of elementary solution principles
(2023)
The paper describes a method for the automated formulation of elementary creative stimuli for product or process design at different levels of abstraction and in different engineering domains. The experimental study evaluates the impact of structured automated idea generation on inventive thinking in engineering design and compares it with previous experimental studies in educational and industrial settings. The outlook highlights the benefits of using automated ideation in the context of AI-assisted invention and innovation.
Established robot manufacturers have developed methods to determine and optimize the accuracy of their robots. These methods vary from robot manufacturers to their competitors. Due to the lack of published data, a comparison of robot performance is difficult. The aim of this article is to find methods to evaluate important characteristics of a robot with an accurate and cost-effective setup. A laser triangulation sensor and geometric referenced spheres were used as a base to compare the robot performance.
The paper compares different anti-windup strategies for the current control of inverter-fed permanent magnet synchronous machines (PMSM) controlled by pulse-width modulation. In this respect, the focus is on the drive behavior with a relatively large product of stator frequency and sampling time. A requirement for dynamically high-quality anti-windup measures is, among other things, a sufficiently accurate decoupling of the stator current direct axis and quadrature axis components even at high stator frequencies. Discrete-time models of the electrical subsystem of the PMSM are well suited for this purpose, of which the method found to be the most accurate in a preliminary investigation is used as the basis for all anti-windup methods examined. Simulation studies and measurement results document the performance of the compared methods.
Digital, virtual environments and the metaverse are rapidly taking shape and will generate disruptive changes in the areas of ethics, privacy, safety, and how the relationships between human beings will be developed. To uncover some of some of the implications that will impact those areas, this study investigates the perceptions of 101 younger people from the generations Y and Z. We present a first exploratory analysis of the findings, focusing on knowledge and self-perception. Results show that these young generations are seriously doubting their knowledge on the metaverse and virtual worlds – regarding both the definition and the usage. It is interesting to see only a medium confidence level, considering that the participants are young and from an academic environment, which should increase their interest in and the affinity towards virtual worlds. Males from both generations perceive themselves as significantly more knowledgeable than females. Regarding a fitting definition, almost 40% agreed on the metaverse as a “universal and immersive virtual world that is made accessible using virtual reality and augmented reality technologies”. Regarding the topic in general, several participants (almost 40%) considered themselves sceptics or “just” users (38%). Interestingly, generation Y participants were more likely than the younger generation Z participants to identify themselves as early adopters or innovators. In result, the considerable amount of “mixed feelings” regarding digital, virtual environments and the metaverse shows that in-depth studies on the perception of the metaverse as well as its ethical and integrity implications are required to create more accessible, inclusive, safe, and inclusive digital, virtual environments.
Als Fortsetzung des FHOP-Projektes wurde an der Fachhochschule Offenburg auf Basis des bestehenden Mikroprozessorkerns im Rahmen einer Diplomarbeit ein Mikrocontroller in ES2-0.7 μm-Technologie entworfen. Der Controller wurde modular aufgebaut mit den Komponenten: FHOP-Mikroprozessor, Buscontroller, Waitstate-Chipselect-Einheit, 16x16 Bit Multiplizierer, 2KB ROM, 256 Byte RAM, Watchdog, PIO mit 16 konfigurierbaren Ports, SIO, 2 Timer und ein Interruptcontroller für 8 Interrputquellen.
Der Chip benötigt bei einer Komplexität von ca. 65400 Transistoren eine Siliziumfläche von etwa 27 mm². Er wurde im September 1996 zur Fertigung gegeben und mittlerweile erfolgreich getestet. Das interne ROM des Mikrocontrollers enthält das BIOS sowie ein Testprogramm. Zur Erstellung der Software steht eine komplette Entwicklungsumgebung zur Verfügung. Sämtliche Komponenten stehen im FHOP-Design-Kit in Kürze zur Verfügung.
Nach dem Nachweis der Funktionalität des an der Fachhochschule Offenburg entwickelten Mikroprozessorkernels FHOP (First Homemade Operational Processor), wird eine Anwendung des Kernels in einem Applikationschip beschrieben.
Der Thermologger-ASIC soll mit Hilfe eines Temperatursensors die Umgebungstemperatur bei technischen Prozessen in regelmäßigen Zeitabständen erfassen und abspeichern. Die Meßwerte werden bei Bedarf ber eine serielle Schnittstelle des Thermologger-ASICs an einen PC übertragen und ausgewertet. Zur Verringerung der Leistungsaufnahme wird zwischen zwei Temperaturmessungen in einen Power-Down-Mode geschaltet.
Der ASIC soll später in einer Chipkarte integriert werden.
Im Frühjahr 1995 entstand die Idee, einen Lottozahlengenerator als Demonstrations- und Studienobjekt, für die Anwendung komplexer digitaler Entwurfsmethoden, zu entwerfen. Mit Hilfe der Schaltung ist es möglich, 6 verschiedene Zahlen zufällig aus 49 Zahlen zu ermitteln. Bei der Ziehung der einzelnen Zahlen werden verschiedene Töne und Melodien erzeugt. Die Schaltung ist so konzipiert, daß eine einfache Bedienung möglich ist. Der Chip wurde als Standardzellen-Entwurf mit einer Fläche von ca. 7 um² geroutet.
An der Fachhochschule Offenburg wurde im Sept. 93 das Projekt eines implantierbaren 16 Bit Mikroprozessor-Kernels FHOP ins Leben gerufen. Ausgehend von dem in einem Testchip erfolgreich erprobten umstrukturierten Entwurf wurde durch gezielten Einsatz von strukturiertem Routen unter Nutzung der Fähigkeiten zum hierarchischen Arbeiten in der MENTOR-IC-Station eine erheblich verkleinerte und flächenmäßig optimierte Struktur abgeleitet, die sich mit 4 Quadratmilimetern Fläche durchaus mit kommerziellen Mikroprozessor-Kerneln vergleichen läßt.
FHOP-Mikroprozessor-Kernel
(1995)
Für die Implementation in ASIC's wurde ein kompakter Mikroprozessor-Kernel als Standardzellen-Makro entworfen. Durch konsequenten Einsatz von Hochsprachen und CAE-Werkzeugen (VHDL, Synthese) konnte ein vollständiges Design in nur vier Monaten durchgeführt werden. Der Prozessor wird in einem Testchip erprobt.
Erstellen von Hardmakros und Aufbau einer Zellbibliothek unter Verwendung des ES2-Library-Kits
(1993)
Es wird eine Anleitung zur Erstellung von Hardmakros mit der Mentor-Graphics-Software gegeben. Die Hardmakros werden mit Standardzellen aus der ES2-Bibliothek der Firma EUROCHIP aufgebaut. Die Hardmakros werden in eine eigenständige Bibliothek abgelegt und können in neuen Chip-Designs verwendet werden.
Mit zunehmend komplexer werdenden Schaltungen wachsen auch die Anforderungen an die Entwicklung einer entsprechenden Leiterplatte. Mit der BOARD-Station von MENTOR-Graphics können professionelle Leiterplatten entwickelt werden.
Im Rahmen dreier Entwicklungsprojekte an der Fachhochschule Offenburg wurden mehrere aufwendige Layoutentwürfe mit der BOARD-Station in verschiedenen Diplomarbeiten durchgeführt. Im Folgenden wird über die dabei gewonnenen Erfahrungen berichtet.
Digitaler Phasenreglerkreis mit numerisch gesteuertem Oszillator als LCA-Microcontroller Kombination
(1992)
Am Beispiel einer Schrittmotor-Indexerschaltung wird der effektive Einsatz von konfigurierbaren Logic Cell Arrays in Zusammenwirkung mit einem Mikrokontroller demonstriert, wobei die hohe Arbeitsgeschwindigkeit des LCAs den Bereich der Schaltung übernimmt und im Regelkreis die arithmetrische Berechnung durchführt. Die Konfiguration des LCA aus dem EPROM des Controllers führt zu einer ungewöhnlichen Flexibilität des Entwurfs und ermöglicht zahlreiche andere Anwendungen mit dieser Architektur.
Die Fachhochschule Offenburg bietet den Studenten des Fachbereichs Nachrichtentechnik seit Ende 1990 das Wahlfach "Entwicklung integrierter Anwenderschaltkreise (ASIC)" an. Ziel des Wahlfachs ist es, den Studenten Grundkenntnisse im Entwurf eines ASIC's zu vermitteln, und wie im folgenden Beitrag aufgezeigt, die Möglichkeit zu bieten, den gesamten Entwurfszyklus von der Schaltungsentwicklung bis hin zur Fertigungsmaske zu durchlaufen.
Die Fachhochschule Offenburg bietet seit dem Wintersemester 1990/91 den Studenten des Fachbereichs Nachrichtentechnik das Wahlpflichtfach ASIC-Design an. Schon kurz nach der Errichtung des ASIC-Design-Centers im Frühjahr 1990 ermöglicht sie damit künftigen Ingenieuren eine Ausbildung in einem Bereich, der in der modernen Schaltungsentwicklung nicht mehr wegzudenken ist.
Im Rahmen eines GPS-Projektes ist an der Fachhochschule Offenburg ein Konzept für einen experimentellen Navigationsempfänger entstanden. Hierfür wurde der digitale Teil entwickelt und aufgebaut. Für die Realisierung der Schaltung sollten benutzerprogrammierbare Gate Arrays von Xilinx (LCAs) verwendet werden, die sich schon bei einer anderen Arbeit an der Fachhochschule bewährt hatten.
Nachfolgend möchte ich dem Leser einen Überblick über das GPS-System und die Entwicklung der LCAs geben.
An der FH Offenburg arbeiten seit Ende 1989 in einem Team die Professoren Dr. Jansen, Dr. Schüssele, die wissenschaftlichen Mitarbeiter Bernd Reinke, Martin Jörger und die Diplomanden Hans Fiesel, Otmar Feißt an dem Entwurf eines Nachrichtenempfängers. Im Rahmen dieses Projekts, genannt GPS-Projekt (GPS = Global Positioning System), wurde im Herbst 1990 ein experimenteller Empfänger in Betrieb genommen. Nachdem die Testergebnisse gezeigt hatten,daß das Konzept der Anlage stimmte, ging es nun um die Miniaturisieriung, Integration und Optimierung der Schaltung. Außerdem sollte der bisher verwendete PC durch einen auf der Platine befindlichen Mikroprozessor ersetzt werden. Im Zusammenhang mit dem GPS-Projekt wurden bisher im Offenburger ASIC-Labor eine Analogschaltung auf einem B500, drei LCA Designs und diverse GAL's entwickelt.
Zur Zeit arbeiten mehrere Diplomanden an der zweiten Generation des Empfängers. Meine Aufgabe besteht darin, die dort noch in drei LCA's untergebrachte digitale Logik sowie einen Teil des bisherigen PC-Interface in einem IMS Gate Forrest zu integrieren. Außerdem muß die Logik von 8 Bit auf einen 16 Bit breiten Datenbus umgestellt und an die neue Peripherie des Mikroprozessors angepasst werden. Damit soll die jetzige Digital-Platine noch weiter verkleinert werden. Wesentlich ist dabei die Umsetzung der zahlreichen Zähler- und Registerstrukturen in einem Gate Forrest. Als Arbeitsmittel stehen Apollo Workstations mit Mentor Software zur Verfügung.
Die Elektronikindustrie bietet für die Realisierung digitaler Logik eine Vielzahl integrierter Bausteine an, die ein Höchstmaß an Zuverlässigkeit als auch Integrationsdichte ermöglichen.
Je nach Integrationsdichte unterscheidet man hierbei zwischen Standardlogik (TTL,CMOS,DTL...), programmierbarer Logik (PLA, GAL...), Gate Arrays und ASIC-Bausteinen. Mit steigender Integrationsdichte werden Systemeigenschaften verbessert, wie Leistungsverbrauch, Platzbedarf, und Zuverlässigkeit.
Jedoch steht ihr auch ein stark erhöhter Kosten- und Entwicklungsaufwand gegenüber, der den Einsatz hochintegrierter Bausteine in Einzelfertigung bzw. Kleinserien verhindert.
Xilinx bietet nun mit seiner LCA-Produktreihe (logic cell array) eine Alternative zu bestehender hochintegrierbarer Logik an, mit der es möglich sein soll, Vorteile der genannten Einzelproduktgruppen zu übernehmen, und deren Nachteile zu beseitigen.
Im Rahmen einer Diplomarbeit wurde ein solcher LCA-Baustein (XC3020) eingesetzt. Anhand der gegebenen konkreten Anwendung konnte hierbei untersuch twerden, wie schnell sich ein solcher Baustein in bestehende Hardware eingliedern läßt, und welche Integrationsdichte er ermöglicht.
Im Folgenden sollen nun als Schwerpunkte das Einsatzgebiet, die Entwicklung und die Simulation des LCA bei vorliegender Aufgabenstellung aufgezeigt werden.
Seit einiger Zeit wird an der Fachhochschule in Offenburg ein Entwicklungsprojekt verfolgt, an dessen Ende ein GPS Empfänger stehen soll. Dabei handelt es sich um einen Satellitenempfänger, mit dem weltweit eine genaue dreidimensionale Standortbestimmung durchgeführt werden kann. Für diesen Empfänger sollte ein Großteil der Analogschaltung, bestehend aus ZF Verstärker, Costas Loop Synchrondemodulator und Pegeldetektor, in das Transistorarray B500a von AEG intgriert werden. Das Chipdesign wurde im Labor für ASIC Design an der FH Offenburg während des Wintersemesters 1990/91 erstellt. Gefertigt wurde der Chip von der Firma AEG in Ulm, wobei die Fertigungszeit des ASIC 6 Wochen betragen hat.
The variable refrigerant flow system is one of the best heating, ventilation, and air conditioning systems (HVAC) thanks to its ability to provide thermal comfort inside buildings. But, at the same time, these systems are considered one of the most energy-consuming systems in the building sector. Thus, it is crucial to well size the system according to the building’s cooling and heating needs and the indoor temperature fluctuations. Although many researchers have studied the optimization of the building energy performance considering heating or cooling needs, using air handling units, radiant floor heating, and direct expansion valves, few studies have considered the use of multi-objective optimization using only the thermostat setpoints of VRF systems for both cooling and heating needs. Thus, the main aim of this study is to conduct a sensitivity analysis and a multi-objective optimization strategy for a residential building containing a variable refrigerant flow system, to evaluate the effect of the building performance on energy consumption and improve the building energy efficiency. The numerical model was based on the EnergyPlus, jEPlus, and jEPlus+EA simulation engines. The approach used in this paper has allowed us to reach significant quantitative energy saving by varying the cooling and heating setpoints and scheduling scenarios. It should be stressed that this approach could be applied to several HVAC systems to reduce energy-building consumption.
Organized by the Fraunhofer Additive Manufacturing Alliance, the bi-annual Direct Digital Manufacturing Conference brings together researchers, educators and practitioners from around the world. The conference covers the entire range of topics in additive manufacturing, starting with methodologies, design and simulation, right up to more application-specific topics, e.g. from the realm of medical engineering and electronics.
The sharp rise in electricity and oil prices due to the war in Ukraine has caused fluctuations in the results of the previous study about the economic analysis of electric buses. This paper shows how the increase in fuel prices affects the implementation of electric buses. This publication is constructing the Total Cost of Ownership (TCO) model in the small-mid-size city, Offenburg for the transition to electric buses. The future development of costs is estimated and a projection based on learning curves will be carried out. This study intends to introduce a new future prospect by presenting the latest data based on previous research. Through the new TCO result, the cost differences between the existing diesel bus and the electric bus are updated, and also the future prospects for the economic feasibility of the electric bus in a small and midsize city are presented.
Im Projekt „BioMeth“ wurden zwei neuartige und bislang noch nicht für die biologische Methanisierung beschriebene Anlagenkonzepte entwickelt. Der neuentwickelte Invers-Membranreaktor (IMR) ermöglicht es, den Eintrag der erforderlichen Eduktgase Wasserstoff H2 und Kohlendioxid CO2 über kommerziell erhältliche Ultrafiltrationsmembranen und den Entgasungsbereich für den Methanaustrag räumlich zu trennen und zusätzlich einen hydraulischen Druck zur Steigerung des Wasserstoffeintrages zu nutzen. Ein Vorteil des Verfahrens ist, dass perspektivisch sowohl das CO2 aus klassischem Biogas als auch CO2-Quellen aus industriellen Abluftströmen, z. B. aus der Zementindustrie als Kohlenstoffquelle genutzt werden können.
Über die biologische Methanisierung hinaus eignet sich der Invers-Membranreaktor der Einschätzung der Autoren nach auch generell zur biotechnologischen Herstellung nicht-flüchtiger Wertstoffe ausgehend von gasförmigen Substraten. Im IMR kann z. B. ein Membranmodul zum Eintrag der Eduktgase verwendet werden, während ein weiteres Hohlmembranmodul zur zyklischen oder kontinuierlichen Abtrennung der wertstoffhaltigen Reaktionslösung unter Rückhaltung der Mikrobiologie im Sinne eines In-situ Product Recovery (ISPR)-Konzeptes genutzt werden kann.
Als herausragendes Ergebnis erwies sich während der Untersuchung des IMR, dass mit dem Konzept der Membranbegasung CH4-Konzentrationen von > 90 Vol.-% über eine einjährige Versuchsreihe kontinuierlich und mit flexiblem Gaseintrag erzielt werden konnten. Nach Inbetriebnahme war dabei außer der Zugabe von H2 und CO2 als Energie- bzw. C-Quelle lediglich eine zweimalige Ergänzung von Supplementen erforderlich. Die maximal erreichte membranflächen-spezifische Methanbildungsrate ohne Gaszirkulation lag bei 83 LN Methan pro m2 Membranfläche und Tag bei einer Produktgaszusammensetzung von 94 Vol.% Methan, 2 Vol.% H2, und 4 Vol.% CO2.
Das zweite noch in der frühen Testphase befindliche Verfahren nutzt Druckunterschiede in einer 10 m hohen gepackten Gegenstromblasensäule, die mit einem ebenfalls 10 m hohen separaten Entgasungs-Reaktor kombiniert wurde. Diese Verfahrenskonzept soll es ermöglichen, eine hohe Wasserstofflöslichkeit aufgrund des am Säulenfuß vorliegenden hydrostatischen Druckes zu erreichen und dabei gleichzeitig den Energiebedarf zu minimieren, die Investitionskosten zu reduzieren und optimale zeitliche und räumlichen Bedingungen für die mikrobiologische Umsetzung von H2 und CO2 zu schaffen. Erste Untersuchungen am Gegenstromblasensäulenreaktor zum Stoffübergang von Luft bestätigten eine gute Anreicherung der im Kreislauf geführten Flüssigkeit bereits bei verhältnismäßig niedrigen Gasleerrohrgeschwindigkeiten. In der zweiten Säule des Reaktoraufbaus sollte am Kopf aufgrund der Druckentspannung ein Ausgasen der im Vergleich zu Atmosphärendruck mit Gas übersättigten Flüssigkeit erfolgen. Das Ausgasen der Flüssigkeit konnte ebenfalls am Beispiel des Lufteintrages bestätigt werden.
An import ban of Russian energy sources to Germany is currently being increasingly discussed. We want to support the discussion by showing a way how the electricity system in Germany can manage low energy imports in the short term and which measures are necessary to still meet the climate protection targets. In this paper, we examine the impact of a complete stop of Russian fossil fuel imports on the electricity sector in Germany, and how this will affect the climate coals of an earlier coal phase-out and climate neutrality by 2045.
Following a scenario-based analysis, the results gave a point of view on how much would be needed to completely rely on the scarce non-renewable energy resources in Germany. Huge amounts of investments would be needed in order to ensure a secure supply of electricity, in both generation energy sources (RES) and energy storage systems (ESS). The key findings are that a rapid expansion of renewables and storage technologies will significantly reduce the dependence of the German electricity system on energy imports. The huge integration of renewable energy does not entail any significant imports of the energy sources natural gas, hard coal, and mineral oil, even in the long term. The results showed that a ban on fossil fuel imports from Russia outlines huge opportunities to go beyond the German government's climate targets, where the 1.5-degree-target is achieved in the electricity system.
During the coronavirus crisis, labs had to be offered in digital form in mechanical engineering at short notice. For this purpose, digital twins of more complex test benches in the field of fluid energy machines were used in the mechanical engineering course, with which the students were able to interact remotely to obtain measurement data. The concept of the respective lab was revised with regard to its implementation as a remote laboratory. Fortunately, real-world labs were able to be fully replaced by remote labs. Student perceptions of remote labs were mostly positive. This paper explains the concept and design of the digital twins and the lab as well as the layout, procedure, and finally the results of the accompanying evaluation. However, the implementation of the digital twins to date does not yet include features that address the tactile experience of working in real-world labs.
The energy system is changing since some years in order to achieve the climate goals from the Paris Agreement which wants to prevent an increase of the global temperature above 2 °C [1]. Decarbonisation of the energy system has become for governments a big challenge and different strategies are being stablished. Germany has set greenhouse gas reduction limits for different years and keeps track of the improvement made yearly. The expansion of renewable energy systems (RES) together with decarbonisation technologies are a key factor to accomplish this objective.
This research is done to analyse the effect of introducing biochar, a decarbonisation technology, and study how it will affect the energy system. Pyrolysis is the process from which biochar is obtained and it is modelled in an open-source energy system model. A sensibility analysis is done in order to assess the effect of changing the biomass potential and the costs for pyrolysis.
The role of pyrolysis is analysed in the form of different future scenarios for the year 2045 to evaluate the impact when the CO2 emission limit is zero. All scenarios are compared to the reference scenario, where pyrolysis is not considered.
Results show that biochar can be used to compensate the emissions from other conventional power plant and achieve an energy transition with lower costs. Furthermore, it was also found that pyrolysis can also reduce the need of flexibility. This study also shows that the biomass potential and the pyrolysis costs can strongly affect the behaviour of pyrolysis in the energy system.
In this paper, we study the runtime performance of symmetric cryptographic algorithms on an embedded ARM Cortex-M4 platform. Symmetric cryptographic algorithms can serve to protect the integrity and optionally, if supported by the algorithm, the confidentiality of data. A broad range of well-established algorithms exists, where the different algorithms typically have different properties and come with different computational complexity. On deeply embedded systems, the overhead imposed by cryptographic operations may be significant. We execute the algorithms AES-GCM, ChaCha20-Poly1305, HMAC-SHA256, KMAC, and SipHash on an STM32 embedded microcontroller and benchmark the execution times of the algorithms as a function of the input lengths.
In recent years, the topic of embedded machine learning has become very popular in AI research. With the help of various compression techniques such as pruning, quantization and others compression techniques, it became possible to run neural networks on embedded devices. These techniques have opened up a whole new application area for machine learning. They range from smart products such as voice assistants to smart sensors that are needed in robotics. Despite the achievements in embedded machine learning, efficient algorithms for training neural networks in constrained domains are still lacking. Training on embedded devices will open up further fields of applications. Efficient training algorithms would enable federated learning on embedded devices, in which the data remains where it was collected, or retraining of neural networks in different domains. In this paper, we summarize techniques that make training on embedded devices possible. We first describe the need and requirements for such algorithms. Then we examine existing techniques that address training in resource-constrained environments as well as techniques that are also suitable for training on embedded devices, such as incremental learning. At the end, we also discuss which problems and open questions still need to be solved in these areas.
Teaching and learning concepts that are adapted to the constantly evolving requirements due to rapid technological progress are essential for teaching in media photonics technology. After the development of a concept for research-oriented education in optics and photonics, the next step will be a conceptual restructuring and redesign of the entire curriculum for education in media photonics technology. By including typical research activities as essential components of the learning process, a broad platform for practical projects and applied research can be created, offering a variety of new development opportunities.
To achieve Germany's climate targets, the industrial sector, among others, must be transformed. The decarbonization of industry through the electrification of heating processes is a promising option. In order to investigate this transformation in energy system models, high-resolution temporal demand profiles of the heat and electricity applications for different industries are required. This paper presents a method for generating synthetic electricity and heat load profiles for 14 industry types. Using this methodology, annual profiles with a 15-minute resolution can be generated for both energy demands. First, daily profiles for the electricity demand were generated for 4 different production days. These daily profiles are additionally subdivided into eight end-use application categories. Finally, white noise is applied to the profile of the mechanical drives. The heat profile is similar to the electrical but is subdivided into four temperature ranges and the two applications hot water and space heating. The space heating application is additionally adjusted to the average monthly outdoor temperature. Both time series were generated for the analysis of an electrification of industrial heat application in energy system modelling.
The contribution of the RoofKIT student team to the SDE 21/22 competition is the extension of an existing café in Wuppertal, Germany, to create new functions and living space for the building with simultaneous energetic upgrading. A demonstration unit is built representing a small cut-out of this extension. The developed energy concept was thoroughly simulated by the student team in seminars using Modelica. The system uses mainly solar energy via PVT collectors as the heat source for a brine-water heat pump (space heating and hot water). Energy storage (thermal and electrical) is installed to decouple generation and consumption. Simulation results confirm that carbon neutrality is achieved for the building operation, consuming and generating around 60 kWh/m2a.
Peer-to-peer energy trading and local electricity markets have been widely discussed as new options for the transformation of the energy system from the traditional centralized scheme to the novel decentralized one. Moreover, it has also been proposed as a more favourable alternative for already expiring feed in tariff policies that promote investment in renewable energy sources. Peer-to-peer energy trading is usually defined as the integration of several innovative technologies, that enable both prosumers and consumers to trade electricity, without intermediaries, at a consented price. Furthermore, the techno-economic aspects go hand in hand with the socio-economic aspects, which represent at the end significant barriers that need to be tackled to reach a higher impact on current power systems. Applying a qualitative analysis, two scalable peer-to-peer concepts are presented in this study and the possible participant´s entry probability into such concepts. Results show that consumers with a preference for environmental aspects have in general a higher willingness to participate in peer-to-peer energy trading. Moreover, battery storage systems are a key technology that could elevate the entry probability of prosumers into a peer-to-peer market.
Robust scheduling problem is a major decision problem that is addressed in the literature, especially for remanufacturing systems; this problem is complex because of the high uncertainty and complex constraints involved. Generally, the existing approaches are dedicated to specific processes and do not enable the quick and efficient generation and evaluation of schedules. With the emergence of the Industry 4.0 paradigm, data availability is now considered an opportunity to facilitate the decision-making process. In this study, a data-driven decisionmaking process is proposed to treat the robust scheduling problem of remanufacturing systems in uncertain environments. In particular, this process generates simulation models based on a data-driven modeling approach. A robustness evaluation approach is proposed to answer several decision questions. An application of the decision process in an industrial case of a remanufacturing system is presented herein, illustrating the impact of robustness evaluation results on real-life decisions.
Most recently, the federal government in Germany published new climate goals in order reach climate neutrality by 2045. This paper demonstrates a path to a cost optimal energy supply system for the German power grid until the year 2050. With special regard to regionality, the system is based on yearly myopic optimization with the required energy system transformation measures and the associated system costs. The results point out, that energy storage systems (ESS) are fundamental for renewables integration in order to have a feasible energy transition. Moreover, the investment in storage technologies increased the usage of the solar and wind technologies. Solar energy investments were highly accompanied with the installation of short-term battery storage. Longer-term storage technologies, such as H2, were accompanied with high installations of wind technologies. The results pointed out that hydrogen investments are expected to overrule short-term batteries if their cost continues to decrease sharply. Moreover, with a strong presence of ESS in the energy system, biomass energy is expected to be completely ruled out from the energy mix. With the current emission reduction strategy and without a strong presence of large scale ESS into the system, it is unlikely that the Paris agreement 2° C target by 2050 will be achieved, let alone the 1.5° C.
In the railway technical centers, scheduling the maintenance activities is a very complex task, it consists in ordering, in the time, all the maintenance operations on the workstations, while respecting the number of resources, precedence constraints, and the workstations' availabilities. Currently, this process is not completely automatic. For improving this situation, this paper presents a mathematical model for the maintenance activities scheduling in the case of railway remanufacturing systems. The studied problem is modeled as a flexible job-shop, with the possibility for a job to be executed several times on a stage. MILP formulation is implemented with the Makespan as an objective, representing the time for remanufacturing the train. The aim is to create a generic model for optimizing the planning of the maintenance activities and improving the performance of the railway technical centers. At last, numerical results are presented, discussing the impact of the instances size on the computing time to solve the described problem.
Lithium-ion batteries show strongly nonlinear behaviour regarding the battery current and state of charge. Therefore, the modelling of lithium-ion batteries is complex. Combining physical and data-driven models in a grey-box model can simplify the modelling. Our focus is on using neural networks, especially neural ordinary differential equations, for grey-box modelling of lithium-ion batteries. A simple equivalent circuit model serves as a basis for the grey-box model. Unknown parameters and dependencies are then replaced by learnable parameters and neural networks. We use experimental full-cycle data and data from pulse tests of a lithium iron phosphate cell to train the model. Finally, we test the model against two dynamic load profiles: one consisting of half cycles and one dynamic load profile representing a home-storage system. The dynamic response of the battery is well captured by the model.
iSign - internet based simulation of guided wave propagation - ist eine Lernumgebung für Online-Laborversuche. Die Client-Serverarchitektur nutzt server-seitig das Tool F3D, das elektromagnetische Felder in 3D-Strukturen berechnet. Ein Apache-Webserver (unter Linux) bedient den Theorie-/Aufgaben-Teil und die Lernsystemadministration. Ein HPUX Simulationsserver steuert und kontrolliert den mehrstufigen Simulationsvorgang. Eine MySQL-Datenbank erlaubt dynmaische Webseiten-Generierung und Simulations-, Projekt- und Userdatenhaltung. Java-Applets, JavaServer Pages und JavaBeans erzeugen die interaktive Client-Oberfläche zur Eingabe, Ergebnisdarstellung und für Online-Virtual Reality. Die einheitlich gestaltete Benutzeroberfläche verbirgt die Systemkomplexität.
Die hochfrequente, feldnumerische Analyse mit der Finite-Differenzen Methode erfordert die Diskretisierung der zu untersuchenden Struktur in einem nichtäquidistanten Gitter. Vorschriften zur Diskretisierung kreiszylindrischer Strukturen wie sie z.B. bei Durchkontaktierungen auftreten, werden untersucht und eine optimierte Lösung vorgestellt.
Virtual-Reality-Darstellung elektromagnetischer Felder in dreidimensionalen Mikrowellenstrukturen
(2000)
Untersuchungen haben gezeigt, daß der Mensch ein Vielfaches an Informationen in Form von visuellen Eindrücken, im Gegensatz zur textuellen Darstellung, verarbeiten kann. Mit Hilfe des numerischen Feld-Simulationsprogramms F3D können Mikrowellenstrukturen auf die Wechselwirkung mit elektromagnetischen Feldern untersucht werden. Das Programm F3D2VRML stellt die Ergebnisse in einer dreidimensionalen Virtual-Reality-Darstellung (VR) dar.
Damit ist es dem Betrachter möglich, mehr Informationen aufzunehmen, da die Informationen mit Formen und Farben im dreidimensionalen Raum visualisiert werden.